Costco Wholesale Essay

1. Executive Summary Costco Wholesale Corporation founded in 1983 by Jim Sinegal in Seatle Washington with a vision & mission â€Å"to continually provide members with quality of goods and services at the lowest possible price control inventory.† Part of their strategy include direct buying relationship that ensures an efficient & strong SC management, high standard staffing plans, high quality products at lower prices and assessable to members who are considered more loyal. Efforts are made to develop strategic options in line with these strategies while focusing on the supply chain parameters that span from order placement to receipt of goods at the warehouse and made available to customers in the warehouse shop floor using the most cost effective processes in order to ensure they support the mission of the company. By assessing Costco’s external opportunities and threats as well as the internal strengths and weaknesses (using SWOT & Porter’s Five Forces analysis), one can infer they are doing well within their industry. More options were generated to increase sales and awareness of the retail warehouses. The report concludes with recommendations for Costco to sustain it’s market edge and advance by expanding into the European & Asian markets more as their presence is still very weak in these regions as well as add other services & goods to their already existing list. 2. Introduction Costco Wholesale Corporation founded in 1983 within the retail industry is the largest warehouse club in the world based on sales volume. A major wholesale business offering three levels of membership and the largest wholesale club operator in the US with membership/warehouse locations spread across Asia, Europe, North & South America with headquarters based in Washington, US. Their main competitors operating membership warehouses include Sam’s Club & BJ’s wholesale club. Jim Sinegal, the founder defines the company vision as â€Å"giving the best to the customer at the best value possible†. Here best value (in quality of goods & services offered) at low prices are the driving force. Costco backs up it’s products with a return policy within a time frame of average 90 days, a highly endearing attraction to it’s members. The business model focuses on low prices & volume purchase in order to achieve profit at low margin with stores offering discounts on an average of 4,000 products out of which roughly a thousand are ‘treasure hunt’ referring to goods that are scarcely available for purchase always. Volume purchase from few vendors yielding further reduction in price and lowers cost in marketing. With low prices, quality goods in limited selection based on forecast lead to quick turnover in inventory. The high volume purchase and efficient network distribution yield efficiency in operations for Costco. With a stipulated membership fee, Costco warehouses are designed to help small to medium size businesses reduce purchasing costs as well as serving large families with the goods packaged in bulk ranging from alcoholic beverages, electronics, fresh food/produce, household & office supplies, pharmaceuticals & tires. Also available are special memberships with services like car & home insuranc e, mortgage and real estate services, and packages for travels. 3.Purpose and Main Areas Of the Research (Concepts & Techniques) Analyzing the supply chain operations at Costco wholesales, in line with the business focus while limiting to it’s supply chain operations strategy for maintaining a competitive edge as it relates to SC operations (from sourcing to arrival on pallets and or display at their various warehouses racks), their challenges and options for improvement will be the focus of this report. The following issues will form questions that will give a frame for this report: †¢ What are the key issues facing Costco in line with (efficient) Supply Chain Operations? †¢ What would be options to compete with these issues?  Ã¢â‚¬ ¢ Which options best suits the business focus and would yield better growth financially? The sections thereafter will consider trying to answer the questions above by applying SWOT analysis (see appendix 1) and Porter’s five forces framework (see appendix 2). Areas needing improvement will be obvious from such, options that would generate better performance after localizing issues peculiar to Costco. These would ultimately lead to clear recommendations for Costco’s improvement. Due to inaccessibility of authentic and current data for successive years on sales, further analysis could not be carried out to compare Costco for accurate sales assessment in the last three years or compare with the other two leading club wholesalers (Sam’s & BJs). Identifying, analyzing key parameters with Supply chain operations processes at Costco and suggest areas of possible improvement. Inventory Management: Since good are moved straight to the selling floor and inventory is not held by Costco but managed by vendors, inventory & labor cost of handling is avoided. In their meat & grocery section for instance, they focus on low-price & high volume strategies hence, Costco carry very limited amounts of grocery & perishables whereas Wal-Mart is known to have weakness in the area of perishables (Petrak, 2006) Partnership/Collaboration with suppliers: Costco has buying relationships with many producers of national brands and are supplied directly from suppliers routing to the warehouses of docking points that serve as distribution points. Partnership market is an attribute of Costco, for instance by partnering with American Express to create a Costco-AMEX credit card, discounts & cash cards as offered to customers while Costco markets Amex cards, thereby helping them to acquire more customers. Distribution Strategies/Transportation: The redesign of product packages to fit into pallets and thereby maximize space has led to reduction of trucks used to transport goods. Cross-docking of goods by delivering directly to Costco stores while some are kept in the distribution centers saves a lot of time & cost along the SC. Utilization of buzzers for truck drives at delivery points to indicate when trucks have been unloaded can save time as against the truck driver’s physical movement within the warehouse is a time saver. Their warehouses are not situated on prime locations hence cost is saved from unnecessary high property cost; again, they own over 80% of the warehouses. Green Logistics: Costco Kirkland signature has launched eco friendly cleaning products. It maximizes the use of solar power in it’s warehouses, it’s delivery trucks are better packaged to allow maximization of space so as to reduce fleets of transportation and hence environmental pollution. Energy is better conserved with timed lighting and construction of warehouses that can maximize skylight during the day. Food products are packaged in recyclable and more environmentally friendly materials. Customers are paid to recycle their old electronics at the green sight. Information Technology: This retailer prides itself in it’s connection of all warehouses to the headquarters in Washington. By using the EFIM which provides real time information, manages control systems and inventory management system. The ECR is used to achieve profitability, improvement in efficiency, logistics, procurement and overall cost control. Kumar (2008) records that approximately $6 billion in a year is lost in the USA by supermarkets due to out of stock products among 25 top retailers as a result of inefficiency in their logistics. Vertical Integration: Costco practices a partial vertical integration with it’s cross-dock distribution. By gaining control of either its inputs or its outputs or both in sourcing directly from suppliers they have more control over innovation & delivery of those services. Cost is also reduced which is ultimately transferred to customers. Further optimization of operational performance through SC operations options that can sustain a competitive edge and improve customer satisfaction through service improvement and cost reduction. 4. Description Of The Separate Areas 4.1Description of The SC Operations Performance & Improvement. The measurement of SC performance can be based on profit, customer service or sales maximization (Chow, 1994). While the traditional method majorly measured product costs, identification of costs related to customer service is key. Elimination of various extraneous costs like plastic shopping bags, fewer shop floor staff, limited product variety & brands on shelf and also slowing down on capital expenditure like expansion, Costco has been able to focus on improving buying power for achieving greater output. Since inventory rates are quickly turned over, payments to suppliers is fast tracked hence they are able to benefit from discounted early payments. Cost is involved in sourcing products from suppliers, shipment to depots & warehouses, distribution to warehouses & storage in inventory. By considering the concept of avoidable cost (possibly considering packaging & storage), efforts can be made to improve on SC performance by implementing better SC integration program. Partnering with more suppliers and or service providers for better flow of operations as well as building keener competition can enhance better efficiency leading to more profit in the long run. More side business services can be added at Costco like money order and cash transfers to attract more customers and make Costco a one stop store. Aside from email messages being sent to existing members on promotions, greater awareness can create a more organized means to lure more customers on the expanding array of products & services such that new & more revenue streams are attained. 4.2 Issues Affecting Supply Chain and Possible Solutions Analysis of SC at Costco using SWOT analysis (appendix 1) reveals Costco is doing really well. Growth opportunities exist for business by entering the European & Asian markets as these have not been exploited. From present methods of operations, the high staff salary and low margins maintenance amongst other issues need to be looked into for future prospects. The aging and close exit of the CEO along with growing competition and other threats in intended foreign markets such as political and religious wars, foreign exchange & bank issues are threats to consider. In dealing with these issues, it will be important to assess briefly lead time management, product handling, transportation, quality, inventory as well as possible process solutions. Where possible, promotions should be done to enhance more sales though with the low prices and already highlighted low margin & high employee, this may eat into the profitability but if well planned can create more publicity for the company which can yield quick inventory turnover. Since low overhead & tight operation is the practice, better savings can be passed on to customers in form of promotion or otherwise. Exploration of overseas market is still a strong force and will yield greater profit considering the existing reputation Costco has and understudying how business is executed in such regions. Development of more private labels on wider product range and increased focus on customer loyalty programs are worth considering as well. It is advisable the board of management put in place a business plan before the exit/retirement of the CEO. Porter’s Five Forces analysis (see appendix 2) could identify an overall attractive industry, with the following power and threat situation: The buyer power was determined to have a positive potential impact on Costco business as it portray that buyers have the requisite level of expendable incomes to provide effective demand for goods & services. In a similar manner, low threat of new entrants and substitute products portray an attractive industry whereas moderate internal rivalry and supplier power have a positive impact on Costco operations as it kept the company alert and devoid of complacency. 4.3 Analyzing The Contribution Of SCOM to Competitive Business Performance To further highlight the role of SCOM in enhancing business performance and maintaining a competitive edge, a few activities like volume purchasing, efficient packaging & distribution, supplier integration & customer integration have contributed to give a close picture of Costco capabilities and business level performance with each activity having unique benefits and detriments. Again, constant review of SCM practices may further help management in Costco to further match demand with SC requirements like efficient, lean SC (Cook et al , 2011). Their Network design, JIT resource planning distribution, optimization of transport & replenishment policies have impacted positively and should be subject to constant review for sustaining a competitive edge. 5. Conclusion Finally, it is believed that some useful contributions are being developed to improve supply chain and it’s operation in line with the objective of Costco in delivering quality at lowest cost to customers on time with the aim of sustaining a more competitive advantage. Some useful SC options have been suggested above which support these objectives. While the ultimate goal remains to sustainably increase market share by achieving more qualitative growth and at the same time expand on the earning base through exploitation of the European market and already existing markets, Mascarehas et al (2004) adds that â€Å"competitive advantage must be won again and again† in other words, giving the current ever changing business world we live in, customer tastes and priorities are changing hence the need for Costco to be better positioned in order to respond always to it’s members needs while expanding on new fronts.

Gun Control Research Essay

ProCon. org recently featured an article that studied gun control. â€Å"Stricter state gun laws associated with fewer gun deaths, study finds. † The article discussed gun control laws in states with stricter laws tend to have lower rates of gun related homicides, and a suicide (ProCon para. 1) Gun control in the United States is becoming a wide spread issue and is becoming a problem everywhere. Although I am living in a city with uprising crime that has been skyrocketing over the years, I wasn’t aware of this being an issue all over the United States.I decided to do some research to find out whether I am in favor of Gun control laws or not. After reviewing many articles for and against gun control, I found out that I do in fact agree with gun control laws. It became difficult to determine my side of the controversy due to there being a lot of negative and positive opinions about the issue. I feel like gun laws should be in place to restore our countries gun related cri me rates in the U. S. The ProCon article argues that states with the strictest gun control laws have lower rates of gun related homicides and suicides.The argument for gun control laws revolve around the statistics of gun control laws being stricter in certain states verses states with not so strict gun control laws. According to ProCon, â€Å"the most restrictive gun control laws have an average of 6. 64 fewer deaths per 100,000 people per year than those with the least restrictive laws† (ProConpara. 1). ProCon continues on to discuss the study â€Å"Firearm Legislation and Firearm Related Fatalities in the United States,† that was studied by different researchers that measured the association between the â€Å"legislative strength of state gun control policies† (ProCon para.1). The researchers then began to study the five categories used to create the legislative strength score which included laws designed to: curb firearm trafficking; strengthen background ch ecks on purchasers of firearms beyond those required by Brandy Handgun Violence Prevention Act; ensure child safety; ban military style assault weapons; and restrict guns in public places (ProCon para. 1). The researchers then ranked all 50 states from 0 to 28 based on their score (ProCon para. 2). â€Å"The higher the score, the more restrictive the gun lawsin that state,† stated the researchers (ProCon para. 2). â€Å"This study is a very important addition to our understanding of the connection between gun control and gun violence,† said John Roman, a PhD, senior fellow. â€Å"In addition to the general relationship between gun safety laws firearm deaths, also suggests that increasing the number of gun safety laws increases the reductions in firearm related deaths. So the benefits just get bigger with more laws† (ProCon para. 3). After reading the ProCon article, I found myself agreeing with the researchers.I can see different levels of gun related crimes all over the United States. Just by living in Fort Wayne, IN where there has been a peak in gun related crimes and deaths gives me proof that their study was indeed accurate. If more states had stricter gun control laws they would start to have lower rates of gun related homicides and suicides. Next, I went to an article by Chuck Baldwin, an American Politician, who disagreed with gun control laws: â€Å"Here we go again. We have another mass shooting at yet another â€Å"gun free† zone.Not only was the location a â€Å"gun free zone, it was located inside the nation’s capital, which has some of the strictest gun-control laws in the entire country,† Stated Chuck Baldwin, (Baldwin para. 1). Mr. Baldwin clearly has a strong disagreement about gun control laws in the United States. In the title of the article, he stated, â€Å"Guns don’t kill people; gun control laws kill people† (Baldwin para. 1). Mr. Baldwin then proceeds to talk about people basicall y abusing gun control laws and that they are useless because people are still using guns in â€Å"gun free† zones. Mr.Baldwin argued, â€Å"I thought gun-control laws and â€Å"gun-free† zones were supposed to protect people from gun violence† (Baldwin para. 1). Mr. Baldwin proceeded to argue that â€Å"Gun-Free† zones are actually â€Å"Free Killing† zones (Baldwin para. 1). He then went on to explain how â€Å"This is the second time in recent memory when some wacko shoots up a military installation† (Baldwin para. 2). I feel like Mr. Baldwin’s logic behind gun control laws is kind of persuasive because even though there are gun control laws, and â€Å"gun free† zones, doesn’t mean that people are going to stop committing gun related crimes in places where there are laws in place.I expected that I might be swayed by Mr. Baldwin’s information, but I was not. I am definitely in favor of gun control laws. I also th ink that Mr. Baldwin’s argument was kind of true and he had a lot of good reasoning, but I still think that by enforcing gun control laws helps a lot of states to lower their gun related crimes. However, I did not see anything on Chuck Baldwin’s article that proved gun control laws were good or bad. The final article that convinced me of my position came from the Congressional Digest.The article, â€Å"Prevalence of Gun Use and the Regulatory Response† doesn’t focus on one side of the issue. Instead, it focuses on the different reasons gun control laws could or could not be effective. Some argue that the low violent crime rates of other countries have nothing to do with gun control, maintaining instead that multiple cultural differences are responsible (Gun para. 1). â€Å"Through the years, legislative proposals to restrict the availability of firearms to the public have raised the following questions: â€Å"What restrictions on firearms are permissibl e under the Constitution?Does gun control constitute crime control? Can the Nation’s rates of homicide, robbery, and assault be reduced by the stricter regulation of firearms commerce or ownership? Would restrictions stop attacks on public figures or thwart deranged persons and terrorists? Would household, street corner, and schoolyard disputes are less lethal if firearms were more difficult and expensive to acquire? Would more restrictive gun control policies have the unintended effect of impairing citizens’ means of self-defense? † (Gun para.2) This article provided a lot of questions that I asked myself and I answered â€Å"yes† to more than half of the previous questions. I had not considered these questions until I read the Congressional Digest. I think that if the government really cracked down on gun control laws, people would actually see a change in gun related crimes. I feel like yes, more restrictive gun control policies have unintended effect o f impairing citizens’, and yes different cultural differences have nothing to do with gun control issues.After reading these articles on gun control laws, I am now more informed and can still say that gun control laws still should be enforced. I am surprised at the different views this issue has received. I found out that I do in fact agree with gun control laws. It became difficult to determine my side of the controversy due to there being a lot of negative and positive opinions about the issue. I feel like gun laws should be in place to restore our countries gun related crime rates and fatalities in the U. S.

Statement of Intent

Statement of Intent The title of my Final Major Project is â€Å"Military Hero†. I will focus on the area of fashion and will work towards producing a small capsule collection consisting of a jacket/coat and a dress that I hope to create and display on show. It will be based around the ever popular military style; which has always been a favourite of mine. In my pathway project my theme was â€Å"Architecture in Fashion† of where I looked at structure and form, I found this theme to be very broad and endless.I also produced a garment based on the theme of shirt-making for a design competition, as I am progressing to University of Ulster to study the BA Hons Degree in Textile Art, Design and Fashion I feel I have made the right area and theme to work with for this project. I will start by looking at period weapons, medals, and armour of which I will use to produce a range of observational studies at A1 size.As I am focusing on Military Fashion I will take my inspiration from fashion designers Frida Giannini, Christopher Bailey, Alexander McQueen and John Galliano as I find their work and style to have elements of what I’m aiming to achieve as a final outcome for my final major project. I will also refer back to the uniforms worn by the armed forces and paramilitaries of various nations. Fashion magazines and the internet as well as my college’s library are also resources I will use. On completion of my visual recording and references I intend to begin the design cycle of the final outcome.I will start by researching the style of garments I shall design through creating moodboard’s relating to colour, style and my military theme; I will then produce a capsule collection board of fashion designs which I will then develop further. Through completing class critiques I will refer to my peer comments and advice from specialism tutors to make a final decision. Once decided I will move on to creating a pattern that will then lead on to the making of a toile this will help me to make any adjustments needed. After this is completed I will compose the final pieces onto fabric that I have chosen.To make sure I do not have to deal with any complications I aim to do each stage two weeks in advance. All work that I do will be critically evaluated as I go along, this will help me to stay on track and I will also record websites, ideas and my schedule in my daily diary. The military styled capsule collection will be on exhibition and modelled on two size 10 mannequins at my college’s end of year show. I will have couture photography of the garments mounted in the background and will also have my project sketchbook displayed on a plinth.If I have any spare time I will also make myself a top based around my military theme. Appendix Bibliography Books: Antonio Mancinelli, (2010), â€Å"Fashion Box: The Immortal Icons of Style†, Thames & Hudson. Richard Martin, (2001), â€Å"The Fashion Book†, Phaidon. Kr istin Knox, (2010), â€Å"Alexander McQueen: Genius of a Generation†, A & C Black Publishers. Bonnie English, (2010), â€Å"Fashion: The 50 Most Influential Fashion Designers of All Time (Icons of Culture)†, Barrons. Websites: Who What Wear http://www. whowhatwear. com/Style http://www. style. com/ Vogue http://www. vogue. co. uk/ Lookbook http://lookbook. nu/ Fashion Is My Inspiration http://fashionismy-inspiration. blogspot. co. uk/ Polyvore http://www. polyvore. com/ Wikipedia http://www. wikipedia. org/ Trendstop http://www. trendstop. com/ Fashion Era http://www. fashion-era. com/ What I Wore http://whatiwore. tumblr. com/ Gucci http://www. gucci. com/ Fashion Net http://fashion. net/ Style and the City http://www. styleandthecity. com/ Alexander McQueen http://www. alexandermcqueen. co. uk .

Case study 4 -BUDGETING STATEMENTS Essay Example | Topics and Well Written Essays - 750 words

Case study 4 -BUDGETING STATEMENTS - Essay Example Hence for 4000 patients visited during the month, the number of hours expected to be spent by the nurses is (4000 * 0.5) 2000 hours. But the actual time spent by the nurses on the patients is 2080 hours. This indicates that an additional 80 hours, i.e, (80 * 12)  £ 960 was spent on the patients. It is essential to investigate the reasons for this variance as the effect of this variance is adverse. As this measure is directly related to the efficiency of the nurses working at the hospital, one of the reasons for this variance might be that some of the nurses might be inefficient (Drury, 2005). The other possible reason could be that, some of the patients might have required additional care and attention which could have resulted in additional hours spent by the nurses. Appropriate action can be taken to improve the efficiency of the nurses can control this variance to a great extent (Blocker, 1951). The cost incurred in terms of the payment made to the nurses amounts to  £ 33,180. However the estimated pay based on the average pay per hour ( £ 12) is computed as (2080 * 12)  £ 24,960. This additional  £ 8,220 also has an adverse effect on the budget. Hence it is essential to understand the reasons for this variance in order to adjust the budgeting accordingly for the future periods. It is known that the pay for the nurses vary from  £ 7 to  £ 28, whereas the average is  £ 12. In the budget prepared, this average was only taken into account. However, the reason for the variance might be that more number of nurses with payment more than  £ 12 were on duty during the month. This variance can be controlled by noting the nurses who will be on duty for the following month and estimating the pay based on their pay scales, instead of using the average pay value. The quantity of supplies and variable heads are associated with the nursing hours as per the statistical studies. According to the standard, an average of  £ 10 worth of supplies and variable overheads are

Wellness project Essay Example | Topics and Well Written Essays - 1750 words - 1

Wellness project - Essay Example First, the physical dimension refers to the physiological state of the body system, ensuring that a person is free from illnesses and maintains physical activity through exercise and healthy diet. If a person is physically healthy, he can function well in the society and make significant contribution to the community. As such, being involved in one’s community also entails responsibility with the surrounding environment. Environmental dimension of health means that a person is able to take responsibility over his environment through protection and conservation of nature. Doing one’s part for environmental conservation also means involving one’s self in the community. As such, a person who builds good relationship with the people in the community shows a healthy social dimension (Corbin et. al., 2008). In a way, building relationships in one’s community is related to emotional dimension because person is capable of recognizing his and other people’s personal feelings. Aside from this, emotional dimension includes the ability handle stress and copes with life’s challenges. While emotional dimension deals with feeling, mental dimension of health deals with cognition or thought. A person is in good mental health if he does not suffer from anxiety and depression. Lastly, if one able to establish inner peace and find deeper purpose in life, it means that the individual is in good spiritual health. Spiritual dimension refers to one’s inner values and realization that we exist for a reason and that each of us has a higher purpose in life. It is only when an individual is able to develop his spiritual dimension, along with other five health dimensions, that we can say one

Should drugs and steroids be legalized in professional sports Research Paper

Should drugs and steroids be legalized in professional sports - Research Paper Example III. Negative Effects of Steroid Use. (i) Risks for the human body (ii) Risks for Men (iii) Risks for Women IV. Steroids in College Athletics and Professional Sports (i) Reasons for steroids use (ii) Testing for Steroid Use (iii) Incidents in the lives of Professional Athletes as a result of Steroid Use V. Steroid Use in the Adolescent Population (i) The "Hero Factor" (ii) Peer Pressure (iii) Risks for Teenagers who abuse steroids VI. Conclusion Ways of discouraging steroid use Name Professor Module Date Should Drugs and Steroids be legalized in Professional Sports? INTRODUCTION Eitzen, Stanley, & George, Sage. Sociology of North American Sport 7th Edition. California: McGraw Hill, 2003. Anabolic steroids refer to group molecules that contain synthetic analogs of testosterone as well as the authentic male sex hormone, testosterone. In the present sports scene, many athletes use anabolic steroids in order to build up on muscle mass. The history of the use of steroids goes back to the 1930s. Steroids first appeared in World War 2 when they were developed for the German army and legalized so that German soldiers could use them to be more destructive in war. After the war, American as well as European doctors often used steroids to take care of blood disorders such as anemia. Today, most steroids are utilized in veterinary medicine in the production of meat. Steroids help in building more muscle in lean beef cattle. Steroids are also used to generate muscle mass in race dogs and horses. According to this Sage and Fitzen, there is evidence to suggest that there are more than 3,000,000 standard anabolic steroid users in America even though they have not been legalized. Most of these users procure anabolic steroids through illegal means. ... Most of these users procure anabolic steroids through illegal means. According to these authors, who have comprehensively addressed different issues concerning the use of anabolic steroids, it is mainly the healthy athletes who turn to steroids in order to improve their already amazing performances in sports. The colloquial name for steroids, by which it is commonly referred in the streets, is ‘juice’ or ‘roids’. Benefits of Steroid Usage Assael, Shaun. Steroid Nation: Juiced Home Run Totals, Anti-aging Miracles and a Hercules in Every High School: The Secret History of America's True Drug Addiction. New York: ESPN, 2007. According to Assael, who has given a graphic account of the extent of steroid abuse among teenagers as well as professional athletes, steroids are not just the preference of athletes in sports that value a ragged physique (Assael 93). Some male and female athletes in different sports fields such as weightlifters, body builders, football pla yers, baseball players, runners, tennis players, basket ballers and swimmers have in the past used steroids to enhance their performances. In the present sports culture where many sport’s body’s have began to institute regulations that call for regular testing of athletes in order to counter steroid use, there are many tests that athletes in competitions like the Olympics have to undergo. This has not been successful in lessening steroid use, but has simply served to cause athletes to come up with more ingenious ways of ingesting steroids. By imitating the anabolic impact of testosterone, athletes believe that steroids help in generating additional tissues, contributes towards muscle recovery when they experience injuries in the field and

Review of the Economic Development Theories in Africa Essay

Review of the Economic Development Theories in Africa - Essay Example This paper offers an analysis of practical implementation of the four models of development in African countries. These models includes Harrod-Domar Model, Exogenous Growth model, Surplus Labor Model, and Harris-Todaro Model. Economic development theories and models are built on three main blocks; the saving function, the production function and labor supply function. Growth rate and saving function are equal to s/AY (where s is the saving rate and AY is the output ratio). South Africa is one of the developing countries in Africa that has implemented the Exogenous Growth Model since it has acknowledged the inclusion of technology and innovation in its plans. This model explains the importance of technological change (and capital accumulation in an economic growth. In Ethiopia Harrod-Domar model applies where high population growth rate is constraint to the rate of technological change. Harrod-Domar model outlines an economic function relationship in which the â€Å"growth rate of gross domestic product (g) depend directly on the national saving ratio (s) and inversely on the national capital/output ration ratio (k) Libya is one of the developing countries in Africa with the highest income per capita GDP, however, most of its population still remain poor and unemployed because of the rural-urban migration in accordance to the Harris-Todaro Model. This is a theory of rural-urban migration and it is strives to address the high rates of unemployment problem issue in the developing countries (Ezeala-Harrison,p3). Rural to urban migration is mainly fueled by the creation of more employment opportunities in the urban areas than the rural areas. This is the reason why most of the Africa’s developing countries such as Kenya have introduced policy of rural industrialization and development to help deal with the problem of high population and unemployment rates in the urban areas. Creation of more industries and other employment opportunities in the rural areas has attracted more people to the rural areas and this is one of the policies required for a balanced development in any country. In developing countries such as Algeria and Tunisia most of the citizens move from their rural homes to urban areas in search of education, employment and high living standards. Some people are also driven away by the poor status of their lands which are unproductive. The current surveys show that about 53 per cent of the populations of Kenya, Tunis, Algeria and South Africa reside in the urban areas. Rapid urban growth rate in the current economic status of the developing countries is a strain to the level of national and local governments to provide basic necessities such as electricity, sewerage, water and adequate health facilities. In such situations, squatter settlements and over crowded slums begin sprawling up. In a country like Kenya over-crowded slums are the homes to millions of the citizens. In most developing countries, this growth rate reflects rural crisis other than urban-based development (Ezeala-Harrison, p5). Harrod-Domar Model Harrod-Domar model outlines an economic function relationship in which the â€Å"growth rate of gross domestic product (g) depend directly on the national saving ratio (s) and inversely on the national capital/output ration ratio (k) (Jurgen & Paul, p257). Mathematically it is expressed as g= s/k. This equation derived its name from two economists (E.V Domar of U.S and Sir Roy Harrod of Britain) who proposed it. This th eory has been majorly utilized by the developing countries in planning their economy in the early post wars. For a targeted growth rate to be realized, a required growth rate must be set. Countries which are unable to set this require savings can resort to a jurisdiction for borrowing from international agencies such as International Monetary Funds and World Bank. Most of the African countries are developing countries which are unable to set the required savings to meet the targeted growth rate. They therefore resort to borrowing from international agencies. Huge debts are disadvantages to developing countries because of the higher interest rates and poor credit (Jurgen & Paul, p257). Problems usually a rise when these countries make irregular loan payment and underestimate the project cost. Every country

China increasing presence in sub-saharan africa Dissertation

China increasing presence in sub-saharan africa - Dissertation Example China despite having high population (over 1 billion people) compared to numerous states globally, the state continues to exhibit a remarkable economic improvement each year (Bloomberg 2010). This is due to its insistence on economic investment not only inside the state but also globally whereby China attains incomparable benefits in return. Some of these benefits/returns to the China embrace available market for their exports, raw materials, imports and even oil. The latter commodity (oil) is almost getting exhausted in the states which China used to rely on besides the US developing political interests in these regions with the intention of dominating the states (Middle East states), hence yielding to stiff competition. Relationship between China and Sub Saharan African region that has yielded to current strong involvement between the two sides is mutually beneficial. This implies the involved parties regardless of their varying economic grounds, maximally benefit from each though due to China’s high demand for raw materials it ended up initiating the move. This is evident from the China’s numerous economic activities evident in SSA region contrary to those of the western states that had initially and up to date invested in Africa (Kaplinsky, McCormick, and Morris 2007). Hence, exhibiting China is out to compete with its rivals (Europe and US) though the tactic is not political as witnessed with US seeming to dominate the other region. China in its quest to attain and ensure cordial relationship with SSA region, embarked on heavy investing that will not only guarantee present benefits but also the future (Kaplinsky, McCormick, and Morris 2007). Hence, being prudent in their actions especially in shunning the areas that have for long maintained a high reputation of rich oil reserves, though currently are undergoing depletion (Broadman 2007). This has prompted China to focus on developing SSA region via establishing and supporting varied key proje cts. Most of these projects encompass those, which for long superpower states (west and US) evaded or heightened their bids especially when negotiating about terms once they finance them. Hence, prompting China to use this opportunity to offer interest-free loans meant for varied states’ projects in this region to back and fund their projects. For instance, this is evident in Libreville where China gave $2 billion and an additional of $6 million loan in return for timber (Ministry of Foreign Affairs, and PRC.2000). This is among numerous interventions and incidences regarding trade, which China has involved itself by concentrating on ensuring cordial relationship with SSA region besides constant flow of raw materials for their home industries. The inception of china’s interest in SSA region started with the tour of President Hu Jintao who ended up entering into various agreements with the key SSA states, for instance, Algerian and Gabon regimes. His core intention enco mpassed seeking constant suppliers of oil for his states. Consequently, this prompted china to finanncing oil exploration projects after signing an agreement with Omar Bongo in Lbreville (China Monitor 2006). In addition, Sinopec and Total-Gabon company made an agreement where the latter was to export 1Millions tons of oil to china (China Monitor 2006). This prompted China to give a loan of 420 Million euro meant to develop Zarzaitine oil field, which was after signing agreement in 2002 (China Monitor 20

Organic compound boiling points Essay Example | Topics and Well Written Essays - 1000 words

Organic compound boiling points - Essay Example In order to figure out the order of organic compound boiling point, it is important to understand their trends. The important thing to make into consideration is that the boiling point is usually indicative of the force strength bonding its molecules together. When many molecules stick together, they will consequently need more energy to break the bonds and release the molecules as gases. Three important trends are considered including branching, which decreases the compound’s boiling point, and the number of carbons as boiling points increases with the increase in carbon atoms. Additionally, the relative strength of intermolecular forces is important (Hill & John, 2011: p32). The strength of the bonds in descending order is; Ionic> Hydrogen bonding> dipole- dipole> Van der Waals forces of dispersion. The influence of these attractive forces is dependent on the present, functional groups. The first trend is the strength, relative for all four compounds, of the intermolecular f orces. Molecules that are held together by dipole- dipole interactions, formed by the polarization of C-O bonds have a lower intermolecular energy when compared to compounds with hydroxyl groups, which are, in turn, capable of forming hydrogen bonds (Macomber, 2009: p11). Organic alcohols have significantly higher boiling points than other organic compounds because of this property, as can be derived. Molecules that have relatively the same molecular weights have their boiling points determined by the present, functional group. 3-Methyl-2-Butanone has a dipole-dipole intermolecular interaction model, and so it has a significantly low boiling point as compared to the other organic alcohols with hydrogen intermolecular bonding (Macomber, 2009: p12). The positive end of one molecule is attracted and bonded to a negative region of another molecule. For molecules with a similar functional group, such as the organic compounds under investigation, the boiling points increase with a rise in molecular weight. The key force that connects molecular size and intermolecular strength is the Van der Waals forces of dispersion that are proportional to the molecules’ surface area (Mehta & Manju, 2009: p29). Therefore, as the length of the chain increases, the surface area of the molecules also increases. Consequently, this results in an increased capability of the molecules in the compound to be attracted to each other. As the length of the chain increases, regions where they line up with each other increase. Each interaction may not be worth a lot, but added up over the entire chain length, the Van der Waals forces of dispersion have the ability to exert tremendous effects (Mehta & Manju, 2009: p29). 1-Hexanol has the highest molecular weight, coming in at 102.67 g/mol1, thus provides more surface area for intermolecular interaction. With the increased energy required to separate the molecules, the boiling point is high. Both 1-Pentanol and 3-Methyl-1-butanol have a mo lecular weight of 88.15 g/mol1, which is still higher than 3-methyl-2-butanone, which has a molecular weight of 86.13 g/ mol. Molecular symmetry is yet another by-product of Van der Waals forces of dispersion’s dependence on surface area. The straighter the compound’s molecules are, the better they line up, as well as bond. The spherical the molecules become, due to branching, the lower the surface area left for intermolecula

Managing Patient safety Assignment Example | Topics and Well Written Essays - 2750 words

Managing Patient safety - Assignment Example The person on whom the medication/ treatment is administered is harmed, and the person who recommends, performs or prescribes the use of the treatment is at fault (MAC, 2010). Each year more than 98, 000 individuals have fatal outcomes medical errors. The errors may arise as a result of doing the wrong treatment wrong treatment, going ahead with the treatment with insufficient information, or due to inefficient processes. About 10 to 20 % of the medical errors are as a result of errors in prescription of drugs or known as ‘medical errors’ (Patel, 2004). The cost of medical errors are very high and this may result in longer hospital stay, post-treatment complications that require a lot of care, etc (Patel, 2004). A more universal definition of a medication consists of any deviation away from the normal intention, expectation or desirability. There are many other ways of perceiving errors includes psychological ways, sensory events, perceptual occasions, cognitively, motor events, any action in well-managed system, and a negative output in a controlled environment Usually an error is related to an adverse effect and even if errors are not caused, they can still occur. For instance even if a drug is perfectly administered according to doses, indications, contraindications, prevention of interaction, etc, an adverse event can still occur as the (Kopec, 2007). Goldberg 2001 considers that the medical errors may have a serious effect on the system such as increasing the patient stay by a couple of days, which adds on to about a spending of $4600 per patient. Overall, with the total number of medical error cases reported every year, about 2.4 million hospital days would be spend and $9.3 billion. The impact is that patients have longer stay (LOS increased), the return to work is longer (indirect costing), and both these direct and indirect costing is preventable to a large extent (Patel, 2004). Most of the medical errors occur at the rate of 1 per day in a hospital, and they have the chance of causing serious negative outcomes for the hospital. Following the medical error, the aggrieved patient has the right to seek damages and compensation. In the year 2008, Medicare declared it would no longer cover for preventable medical errors in healthcare. Today with the introduction of such measures from the CMS and insurance companies, greater efforts are being laid in reducing medical errors as the hospitals are being held responsible (Patel, 2004). A medical error can be related to various aspects of healthcare including:- On a large scale, it is found that from the physician quarters about 57 to 60% of the errors can be prevented if a computerized ordering system is implemented and can be used appropriately (Maganelli, 2009). Patient Safety According to the AHRQ, patient safety is defined as â€Å"...as a discipline in the health care professions that applies safety science methods toward the goal of achieving a trustworthy system of he alth care delivery...’. Here greater efforts are being placed on trust in the healthcare delivery system (AHRQ, 2008). According to the IOM, patient safety is defined as â€Å"...the prevention of harm to patients...† They have placed greater emphasis preventing errors, learning from past errors, building a culture that is safe for the patients including efforts from organisation, professionals and the patients (Mitchell 2008). During

Research a Fortune 500 company Paper Example | Topics and Well Written Essays - 1250 words

A Fortune 500 company - Research Paper Example Introduction Wal-Mart is regarded as an American based multinational retail business corporation. It is one of the top companies which regained its position in the Fortune 500 list as per the 2012 report. The company emphasized providing quality products to the customers at a reasonable price which supported it to regain its position in the market (Duke, 2012). The management and the marketing strategies that adopted and used by Wal-Mart have a great impact on its increasing sales and the revenue earned. The foremost reasons for the success of Wal-Mart include its effective management, making deliberate efforts to attain its vision and growth among others which are in turn providing the business of the company an edge over others. Management and Marketing Strategies Wal-Mart developed a business model which focused on providing greater satisfaction to the customer with the deliverance of low price products to them. The management of the company followed upon developing its marketing mix strategy. In terms of analyzing management strategies of Wal-Mart, it can be viewed that the management of the company took steps to offer reasonable prices to the different product ranges that they deliver to the customers. The management segments the product type based on the buying capacity of the individuals. In relation to marketing strategies, the company emphasized promoting its broad assortment of products through using hoardings, leaflets and offering special discounts. In this regard, it can be affirmed that the management of the company desires to attract the customers by creating a positive brand name and recognition in the business markets where it operates. Relating to marketing strategy, the management team of the company developed a slogan as a way of promoting its varied products i.e. "Everyday Low Prices."Â   Continuous innovation and the use of technology for making the customers more satisfied are the other managerial approaches that used by Wal-Mart. It can be apparently observed that technology innovation at Wal-Mart typically involves process and service invention that helps in reducing operational costs and time at large. In this context, the management followed three policy goals i.e. respect for individuals, facility to customers and determination for excellence (Hayden et. al., 2002). Different Business Life Cycles that Endured By Wal-Mart The Prosperity Phase- This phase is regarded as the growth phase of any company which is marked by strong economy and market presence. In this similar concern, Wal-Mart maintained this particular phase by offering "high-quality," along with branded products at low prices and also by forming several stores in small towns. Wal-Mart uses the discount merchandising strategy in order to increase the demand and the sales of its products and hence accomplished superior competitive position over others. In relation to this particular phase, the company is growing rapidly due to diversification strateg y that it follows and expanding its outlets in small towns. Another reason for the company to flourish in this modern business market is focusing on delivering high customer services. Due to excessive demand of the products, the management of the company absorbed more employees during this phase (Hayden et. al., 2002). The Recession and Recovery Phase- This is the business phase which exhibits expansion by a significant level. This particular pha

Discuss the role played by Mr. Morrison Essay Example for Free

Discuss the role played by Mr. Morrison Essay Mr. Morrison symbolises the strength of Afro-Americans in the face of adversity. He is a source of courage and protection for the Logan family, acting almost as a guardian angel when papa is not home. There is an air of myth surrounding Mr. Morrison, created by factors such as his stature, his deep voice and scarred features. This makes him an interesting and thus successful character for Mildred Taylor. When the children first meet Mr. Morrison, his description relates directly to Mildred Taylors imagery. The attention that she pays to the significance of trees as an emblem of strength, influences her description of the powerful Mr. Morrison: The man was a human tree in height, towering high above papas six feet two inches. The long trunk of his massive body bulged with muscles The living strength and permanence of trees are a symbol of the strength which the black community draws from its history, tradition and inheritance, and the roots which have been put down in their land. Thus, the description of Mr. Morrison is in keeping with such imagery. The timing of Mr. Morrisons arrival assists Mildred Taylor in developing tension and suspense. He arrives on the scene in the wake of the news of the attack on The Berry Family. Mr. Morrison, we learn, was wrongly accused of starting a fight and then sacked from his job. This gives us an example of institutionalised racism and also hints that there may well be more incidents and fights. The children immediately warm to him and are deeply fascinated by his giant-like appearance. Mr. Morrisons attributes make him immune to the physical threats by which the local whites terrorise the black community. This gives the children courage and inspiration. As a result he is a figure who earns Staceys respect. Stacey becomes much closer to Mr. Morrison after he makes it plain that he will not be reporting the matter of the fight to with T. J to Staceys mother. Indeed, such is Mr. Morrisons positive influence, that Stacey shows increased maturity by telling his mother about the fight himself. On their way back from shopping in Vicksburg, Papa, Stacey and Mr. Morrison are ambushed by the Wallaces. Mr. Morrison shows his tremendous power by taking on three attackers and badly injuring two of them. In the following chapter he again demonstrates power and shrewd judgement too by lifting Kaleb Wallaces truck. This act is enough for him to avoid being drawn into fighting whilst still standing up for himself. By checking the truck for a gun first, Mr. Morrison shows an admirable measured determination not to be bullied. Furthermore, Mr. Morrison is a vital calming influence upon the headstrong Hammer when the childrens uncle is seeking to avenge Cassies humiliation in strawberry. The image of Mr. Morrison sat watching on the porch for the nightmen is a very powerful one. To the Logans he is a guardian angel figure, who protects with great strength, yet is otherwise the perfect example of calm. In the stories he tells to the family we learn of an horrific past in which his family were murdered by racists. His scars symbolise the healing power and capacity to endure that are characterstic of the persecuted black people. His voice like the roll of low thunder further emphasises Mr. Morrison as a key symbolic figure in the book, as this simile echoes the title. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Mildred Taylor section.

Installation Of Storage Tanks Construction Essay

Installation Of Storage Tanks Construction Essay The proposal contains the detailed scope of works on various discipline of the tender, procedures developed for execution of Storage tank construction of the project Construction of Oil Terminal, the purpose of this technical proposal is to provide clear direction in the form of procedures, controls and administration practices in order that the services provided by contractor are in accordance with the tender and contractual requirements and in accordance with CGL internal quality systems and procedures. The intent of this document is also to communicate the execution strategy to all concerned. Proposal Purpose : This proposal sets out the scope, programme and terms to provide a single window service, with all the expertise and technical competence for the entire work related to the storage tank construction as given below. Design and engineering Procurement of materials for the tanks Fabrication Field erection , welding and testing Surface preparation , painting Assistance during Pre commissioning, commissioning and training All the works shall be carried out as for the completeness of the project. This proposal is in accordance with the engineering specifications, drawings, all the statutory regulations and international codes and standards have been considered in our proposal for this Job. Basis of offer Proposal is based on tender enquiry, data sheets, specifications, drawings issued as the tender documents. Validity This proposal will be valid for acceptance within 60 days from the date of commercial tender submission any further extension on proposal validity shall be subject to mutual agreement between the client and contractor. B. Detailed Scope of Works 1 Proposed List of Tanks Sr. No Tank Tag no Product Type Qty (Nos.) Capacity m3 Size in Meter Diameter Height 1 T-2011/2012 Gas oil / UGL EFR (single deck ) 2 750 11.5 8.5 2 V-4011 Jet A1 Horizontal 1 10 2 3 3 TF-T-2005 ULG 98 EFR (single deck ) 1 5000 22.5 15 4 V-2011 ULG 91/95/98 Horizontal 1 10 2 3 5 T-7001/T-7002 Firewater CS Dome 2 6500 22.5 19 6 TF-T-2003/2004 ULG 95 EFR (single deck ) 2 20000 36 22 7 V-1011 Gas oil Horizontal 1 10 2 3 8 TF-T-1001/1002/1003 Gas oil EFR (single deck ) 3 20000 36 22 9 TF-T-2001/2002 ULG 91 EFR (single deck) 2 20000 36 22 10 T-5001/5002/5003/5004 Jet A1 CS Dome 4 24000 41 22 2. Scope of Supply and Works 2.1 Scope of Supply All permanent material for tanks such as Plate Materials, nozzles manholes, wind girder and stiffener etc. required for the tanks. Internal External floating roof, Floating roof Seal, all the permanent accessories of the Floating roof. Internal and external accessories indicated on data sheet Clips for platform/ladder/pipe support directly welded on tank body. Bolts/nuts, clamps, gaskets for internal Blind flanges together with bolts/nuts and gaskets for blinded nozzles and manholes Davits and/or hinge for manholes. Vortex breaker (if required). Platforms, spiral stairway with handrails, roof handrail. Internal pipe with support Breather valves/ emergency drain / Rim vents and gauge hatch (if required). Name plates with bracket Earth bosses or lugs Settlement check lugs Support clip for firewater and Foam system piping connected to the tank. Surface preparation and Painting material for equipment Test plate for PQT and WPQT Spare parts of gasket and B/N for construction and pre-commissioning. Construction Equipments Electricity for construction.(fabrication and erection ) Heavy equipment, all machineries and other facilities for construction Welding rods, grinding wheels, cutting gases and other Miscellaneous Consumables for construction All the NDT equipments for testing and inspection Hydraulic Jacks Power Pack for the tank erection Pumps temporary pipes and fittings for hydro testing Tools and jigs including scaffolding for construction Consumable material for erection Blind flanges together with bolts/nuts and proper gaskets for hydrostatic test Corrosion inhibitor for hydrostatic test (if required) Direct and Indirect Manpower Dedicated design and drafting item for the project. Dedicated Construction management team at site Dedicated project management at Office Supervisory staff for Fabrication and erection QA/ QC personnel for testing and inspection Safety and EHS officers a site Skilled, semi skilled and unskilled man power for the fabrication and erection and testing at site 2.2 Scope of Work Mechanical design (strength calculation and detail design) Loading data for tank foundation design. Manufacturing drawings Documentations (procedure fabrication construction, ITP and others) Submission of as-built documents and drawings Material procurement Shop fabrication Packing list (packing volume, size weight, etc) Packing and inland transportation of shop fabricated components. Unloading of materials at site PWHT for 1st course shell with nozzles as per code requirement. Hydro-test and water drainage as broom clean condition after hydro-test and drying Settlement checking during hydrostatic test Temporary work of utility for construction and test Site construction Inter connecting walkway between tanks. Inspection test at shop and test. Surface preparation and painting for exterior surface as per specification. Internal Coating as per spec Hot dip galvanizing of tank handrails and staircase Project management and control Third party inspection agency review Attending the meeting with client and consultant Over all construction management of storage tank package Documentation for government approvals if any Mechanical guarantee Other activities to meet requirements of inquiry 2.3 Out of Scope of Supply Work Tank foundation and civil works Oil Pass required for the site crew and staff. Electrical, Instrumentation accessories Process Piping, Plant piping, inter connecting pipes between tanks. Cabling (including earth cable) and wiring materials. Supply of anchor bolts (if required)/ Grouting for tank bottom All kinds of valves including shut-off valves for draw-off sumps and external piping. Companion flanges and bolts/nuts Pumps , Heaters , Hearting coils if any Insulation material and work (if required) Fire protection material and work Customs clearance and taxes duties if any Government permit and approval (for local regulation) Tank Gauge (Radar Type) Level instruments (High Low) and transmitters All kind of instrumentation and Electrical works Lightning protection if any , Earthing 2.4 Facilities to be provided by Client Oil passes for our crew and staff. Adequate space for the Lay down area in the vicinity of site Adequate space for the fabrication and painting yard in the vicinity of site(if space is not provided we will fabricate Prime the tank plates at our fabrication shop in Dubai and transport it to sites for erection ) Site office for our staff Rest room facilities for our crew C. Project Execution Design and detail engineering : Contractor In house Fabrication and shop priming: At site(if fabrication area is available) If no area is available at site, then fabrication will be done at our fabrication shop Erection at site: Contractor In house team Surface preparation and painting through reputed sub contractors. Typical Project Execution Plan Project execution plan organization Contractor formal role in the project implementation will commence from the signing of the Agreement between the Client and Contractor. However, the effective participation of the contractor will start from the date of receipt of letter of intent (LOI) and the project kick off meeting, where project scope and basis will be formally agreed. Contractors Organization Charts The Contractor will appoint a Project Manager to take total charges of scope of work for which they are responsible. The structure is shown in the organization charts. 1.2 Overall Project Execution The Project Manager and his team are the primary interface point between the Contractor and Client. It is via this interface that all the day-to-day correspondence passes and project report are issued. The Project Manager with his team oversees the contractors scope of work. The projects coordinator is responsible for the coordination between Client, Engineering, Procurement, Fabrication and the Site Operation. As soon as LOI is issued internal Kick-off meeting will be held to firm up the project procedures. In order the successfully achieve its objective the Project Manager issues the Project Dossier detailing the interface between Contractor and the Client. It sets out the detailed working method to be employed by them though all phases of the job. With the co-ordination procedure the project schedule and methods of measuring progress and controlling the work are also issued. Inventory Procedure Quality Control Shipping Procedure and Forecast Field Project Control Procedure Field Safety Procedure Change Order Procedure. 1.3 Design and Engineering The Client has given the basic design. The detailed design for Contractor (in house) will carry out the project 2. Procurement Sub- contracting Contractor will prepare material requisition for all plant, equipment and materials and the Procurement in-charge shall manage the procurement and sub contracting. He will establish the procurement plan, identifying the finite list of requisition to be issued by the engineering groups, to start procurement cycle. Contractor will issue enquiries and obtain offers. Purchase orders will be placed by the contractor on vendors approved by Client, offering best Techno-commercial terms. A list of critical long lead items will be established including long lead item and those critical to programs. Special monitoring of these items will be carried out to ensure timely delivery. Procurement service offered by the contractor will include bid evaluation, arranging vendor coordination meetings, selection, placement of purchase orders, amendment of purchase order and modified if necessary, to reflect any specific requirements of the specific order. 3. Construction Contractors Construction group will supervise the construction to be carried out in a phased manner. It will be responsible for field inspection, material and inventory control and logistics for timely executing of the project. Contractors Project Manager will ensure quality and schedule so that the construction is done as per the detailed design/engineering document prepared by Client and within agreed time frame. 4. Pre-commissioning and commissioning The Commissioning Group headed by the Commissioning Engineer of the contractor will direct and supervise to provide the necessary assistance to the pre-commissioning and commissioning activities of Client. Project in co-ordination with the Commissioning in-charge of Main contractor/consultant. The major activities of this group will include: Check plant units for mechanical completion at size. Prepare pre-commissioning programme to assign priorities during final stage of counteraction work. Planning and scheduling of plant start up activities. Co-ordinate and supervise the start up of the plant. Main contractor/consultant shall conduct process guarantee test turns. 5. Project scheduled, control and reporting Contractors system of project planning scheduling and monitoring is designed to provide comprehensive planning services to the project management team. This system is instrumental in devising realistic schedules establishing checkpoints, keeping overall watch on the progress, deviation from schedules, pinpointing the problem and recommending areas of corrective actions. The details are given below: 6. Planning Scheduling 6.1 Proposed Schedule and overall project schedule The proposed project schedule is submitted along with this proposal. This indicates the project starts date, end date and major milestones of the project the proposed schedule is prepared in the form of bar chart schedule. On award of the control, the proposed schedule is converted into an overall project schedule in the form of squared PERT network on time scale. This network includes overall engineering, procurement and construction duration as well as critical and near critical items for each system. This overall schedule forms the basis for execution of the contract and is used for corporate project review. 6.2 Master Network For project control, master network is prepared for the project, master network is updated internally every month, this is revised if (i) The overall project schedule is revised, (ii) There is a major change in the scope of work, (iii) unforeseen events beyond contractors control. The master network forms the basis for detailed scheduling and project control. 6.3 Function Schedules At the level of the executing departments, functional schedules are prepared for all functions, viz. process, residual engineering, ordering and delivery. Standard Networks for various functions are used for sequencing various activities in the schedules. These schedules are also used for scheduling projects physical progress and its measurement. 6.4 Key Construction Network This network is delivered from master network. This is made, work area wise, on time scale The number of networks to be prepared depends upon the workload into which the plant is divided. These networks are prepared at a time when engineering and procurement activities have sufficiently advanced and construction activities are about to begin or major milestones such as deliveries of equipments at site, start and completion of civil works, mechanical erection etc., are about to be achieved. 6.5 Reports Basically, three types of reports are produced. First type of report contains activities to be performed in next two months and is known as Activity List. Second type of reports gives the status of drawings, materials, etc. and is named Status Report, which highlights the deviations and exceptions and immediate actions. The Third Type of Reports is the one, which summarize progress report at various time intervals. 6.6 Monthly Progress Report Monthly progress report is basically meant for Client. This report gives a comprehensive coverage of engineering, procurement and construction activities carried out during the month under review. The monthly report apprises the Client of the progress of the project and holds up if an in achieving the progress. The report contains the following information: Overall progress statistics Status of milestones List of problems/hold ups Functional progress curves Quantitative status report for equipment Detailed status of construction D. Work Breakdown Structure E. Bar Chart (Project Schedule) Please Refer Annexure I Project Organization Chart G. Man Power Deployment Schedule H. Construction Equipment Deployment Schedule List of Proposed Vendors and Suppliers Sr No Description Supplier Origin 1 Carbon Steel Plates Corus European(West / East) For tanks Arcelor Mills European(West / East) Posco Korea Dongkuk steel Korea Duffer co Belgium Dillinger Hutte Germany Nippon steel Japan Stemcor South Africa Sumittomo Japan 2 Carbon Steel Pipes Dalmine Spa Italy Manses man Brazil / Germany Nippon steel Japan NKK steel Japan Kawasaki Japan NSC Japan Hyundai pipes Korea Korea pipes Korea 3 Carbon Steel Pipe Benkan corp Korea Fittings Awaji sangayo Corp Japan BKL UK BKL Thailand OMR Italy Techno forge Italy Tect tubi Italy Vanleeuwen Holland 4 Flanges Bebitiz Germany FAD flange Italy Geldbech Germany Korea flange Korea 5 Floating Roof seal Ultra float USA Korea Flot Korea HMT USA CTS Nether land 6 Paint International Paint Jotun Hempel Sigma Responsibility Matrix SR.NO DESCRIPTION Division of Responsibility (subcontractor) (Main Contractor) A ADMINISTRATION 1 Visa/work Permit à ¢Ã‹â€ Ã… ¡ 2 Accommodation à ¢Ã‹â€ Ã… ¡ 3 Food à ¢Ã‹â€ Ã… ¡ 4 Transportation à ¢Ã‹â€ Ã… ¡ 5 Site first Aid Facilities à ¢Ã‹â€ Ã… ¡ B TAXES DUTIES / INSURANCES 1 WCP Insurance à ¢Ã‹â€ Ã… ¡ 2 Automobile Insurance à ¢Ã‹â€ Ã… ¡ 3 Captial machinery insurance à ¢Ã‹â€ Ã… ¡ 4 Contractor All Risk Erection Policy à ¢Ã‹â€ Ã… ¡ C FACILITIES 1 Laydown yard / Fabrication Yard à ¢Ã‹â€ Ã… ¡ 2 Stores à ¢Ã‹â€ Ã… ¡ 3 Site office facilities à ¢Ã‹â€ Ã… ¡ 4 Worker rest room toilets à ¢Ã‹â€ Ã… ¡ 5 Parking Spaces for Vehicles à ¢Ã‹â€ Ã… ¡ 6 Drinking water Portable water à ¢Ã‹â€ Ã… ¡ 7 Electricity for site office and rest room à ¢Ã‹â€ Ã… ¡ 8 Electricity for Fabrication à ¢Ã‹â€ Ã… ¡ 9 Blasting and Painting Facilities à ¢Ã‹â€ Ã… ¡ 10 Carbagge Disposal à ¢Ã‹â€ Ã… ¡ 11 Hazardous Mateial Disposal à ¢Ã‹â€ Ã… ¡ 12 Removal of Construction Debris à ¢Ã‹â€ Ã… ¡ 13 Electricity for Site Construction à ¢Ã‹â€ Ã… ¡ 14 Safety Interface with Client à ¢Ã‹â€ Ã… ¡ 15 Personal Protection Equipments à ¢Ã‹â€ Ã… ¡ D DESIGN ENGINEERING 1 Design à ¢Ã‹â€ Ã… ¡ 2 Engineering à ¢Ã‹â€ Ã… ¡ 3 Detailed drawings à ¢Ã‹â€ Ã… ¡ 4 Support details à ¢Ã‹â€ Ã… ¡ 5 Structural Drawings à ¢Ã‹â€ Ã… ¡ 6 Asbuilt Drawings à ¢Ã‹â€ Ã… ¡ E PROCUREMENT SUPPLY 1 Direct Material (Plates for shell bottom and roof, Structural for stairway, roof handrail and roof structures) à ¢Ã‹â€ Ã… ¡ 2 Consumables à ¢Ã‹â€ Ã… ¡ 3 Gaskets / Bolt / Nuts for hydro testing à ¢Ã‹â€ Ã… ¡ 4 Permanent Gasket/Bolt/Nuts à ¢Ã‹â€ Ã… ¡ 5 All Galvanized items for platform/stairway etc à ¢Ã‹â€ Ã… ¡ 6 All tank mounting appurtenances and Instruments à ¢Ã‹â€ Ã… ¡ 7 Material unloading at site à ¢Ã‹â€ Ã… ¡ F Plant Machinery At Site 1 Crane à ¢Ã‹â€ Ã… ¡ 2 Hydra Crane à ¢Ã‹â€ Ã… ¡ 3 Fork Lift à ¢Ã‹â€ Ã… ¡ 4 Rolling Machine à ¢Ã‹â€ Ã… ¡ 5 Welding Machine à ¢Ã‹â€ Ã… ¡ 6 Generators à ¢Ã‹â€ Ã… ¡ 7 Hydraulic Jacks System (Jacks, power packs, hoses, accessories etc.) à ¢Ã‹â€ Ã… ¡ 8 Tools such Grinding, cutting ,beveling Etc à ¢Ã‹â€ Ã… ¡ G PRE FABRICATION 1 Plate cutting Edge preparation (Shell, Roof, Bottom Annular) à ¢Ã‹â€ Ã… ¡ 2 Sand Blasting and Painting of internal and external surfaces of tank as per client approved Painting procedure. à ¢Ã‹â€ Ã… ¡ 3 Shell plate rolling à ¢Ã‹â€ Ã… ¡ 4 Nozzles Manway Neck Rolling à ¢Ã‹â€ Ã… ¡ 5 Sump Plate Rolling, Welding External painting à ¢Ã‹â€ Ã… ¡ 6 Roof Structure and Floating Deck prefabrication à ¢Ã‹â€ Ã… ¡ H CONSTRUCTION 1 Civil work à ¢Ã‹â€ Ã… ¡ 2 Instrumentation à ¢Ã‹â€ Ã… ¡ 3 Tank Insulation à ¢Ã‹â€ Ã… ¡ 4 Scaffolding for Erection and painting, if any à ¢Ã‹â€ Ã… ¡ 5 Tank Erection -Bottom ,Annular, Shell, Roof, Roof Structure, Floating Deck , shell Roof Nozzles Man way, Sump à ¢Ã‹â€ Ã… ¡ 6 Painting Jobs as per client approved procedure à ¢Ã‹â€ Ã… ¡ 7 Meeting Clients construction Schedule à ¢Ã‹â€ Ã… ¡ I TESTING 1 Liquid Penetrent Testing à ¢Ã‹â€ Ã… ¡ 2 Magnetic Partical Testing à ¢Ã‹â€ Ã… ¡ 3 Radiographic Testing à ¢Ã‹â€ Ã… ¡ 4 Ultrosonic Testing if any à ¢Ã‹â€ Ã… ¡ 5 Post Weld Heat Treatment if any à ¢Ã‹â€ Ã… ¡ 6 Facilities for Hydro-testing à ¢Ã‹â€ Ã… ¡ 7 Water for Hydro Test à ¢Ã‹â€ Ã… ¡ 8 Drain point for hydro-tested water near to tank bottom (Max 250 M) à ¢Ã‹â€ Ã… ¡ 9 Dewatering Drying à ¢Ã‹â€ Ã… ¡ 10 Tank Calibration à ¢Ã‹â€ Ã… ¡ J HANDING OVER 1 Punch list à ¢Ã‹â€ Ã… ¡ 2 RT film Submission à ¢Ã‹â€ Ã… ¡ 3 AS Built Drawing à ¢Ã‹â€ Ã… ¡ 4 Final Dossier submission à ¢Ã‹â€ Ã… ¡ 5 Pre commissioning assistance à ¢Ã‹â€ Ã… ¡ 6 Commissioning assistance à ¢Ã‹â€ Ã… ¡ K GENERAL 1 Third Party Inspection Costs à ¢Ã‹â€ Ã… ¡ 2 All the approvals from Local authorities à ¢Ã‹â€ Ã… ¡ 3 Necessary gate passes / permits to carry-out our works à ¢Ã‹â€ Ã… ¡ 4 Coordination with Client à ¢Ã‹â€ Ã… ¡ Project Estimation Summary Sr.No. DESCRIPTION QTY. Unit Rate Amount I PRELIMINARIES Mobilization of Manpower/Equipment 1 70,000 70,000 Establishment of site facilities 1 200,000 200,000 Insurance 1 200,000 200,000 Demobilization of Manpower/Equipment 1 70,000 70,000 Design/Engineering 1 80,000 80,000 Documentation 1 30,000 30,000 Sub Total AED 650,000 II PROCUREMENT Steel Plates( A 537 Cl.1 ) 3,363 2,931 9,856,953 Steel Plates( A 36 ) 2,258 2,488 5,617,904 Structural 96 2,800 268,800 Pipes Fittings/Flanges 1 510,000 510,000 Fasteners 8 7,000 56,000 Aluminium Dome 1 7,000,000 7,000,000 Hatch / Accessories 1 Jet Mixer + Misc 8 Galvanizing 8 5,000 40,000 Stairway Steps 8 16,500 132,000 Sub Total AED 23,481,657 III CONSTRUCTION Sub-Contract 5,450 1,000 5,450,000 Consumables 1 100,000 100,000 Safety Equipments 1 398,200 398,200 Salary for Staff 1 500,000 500,000 Wages for Fabrication Crew 1 Wages for Erection Crew 1 Equipments ( Hire) 1 1,661,000 1,661,000 Equipments ( Purchase ) 1 600,000 600,000 Mobilization of Pre fabricated material to site 1 320,000 320,000 Scaffolding Erection Tools tackles 1 42,000 42,000 Fuel 1 617,400 617,400 Freight, Visa ,Food Accommodation for Crew 2,663,200 2,663,200 Testing Requirement 1 Site Communication/Stationary/Utilities 1 Office Communication/Stationary 1 Heating Nitrogen Coil 1 3,849,468 3,849,468 Sub Total AED 10,751,268 IV SUB-CONTRACT Civil Foundation Misc. Works 1 8,389,450 8,389,450 Civil Design 1 Soil Improvement 1 Reduce backfilling (1 M) 1 Surface Preparation Painting 1 2,476,700 2,476,700 Belzona application 1 NDT works 1 1,150,000 1,150,000 Third Party Inspection 1 150,000 150,000 Calibration 1 64,000 64,000 Hydro Test 1 200,000 200,000 Sub Total AED 12,430,150 V OTHERS BG Charges 100,000 Finance Charges 150,000 Commission to Agents

Types of Waste

Types of Waste Waste is known as a matter which current users have no purpose of, or it is known as a matter which can be harmful to humans, animals or the environment. Waste can be divided into two categories, general and hazardous waste. General waste is waste that does not harm humans, animals or the environment. For example household waste, garden waste, building rubble, dry industrial and commercial waste. Hazardous waste is more likely to cause danger to humans, animals and the environment. This waste is based on the chemical reactivity, explosives, corrosive and radioactive. Waste Found In the Community of Edenvale There is many different waste found in the community which affect the community. The types of waste found in my community are agricultural waste which comes from animal products and the production of crops. This waste can be recycled. Biodegradable waste is a type of waste that will go back into the soil and nature. This may include garden waste, animal waste, fruit and vegetable leftovers. This waste can be composted. Garden waste is known as grass clippings, weeds, tree branches and this can all be composted. Bulk waste is large waste, such as broken appliances, furniture and outer parts. Almost all of this waste can be reused or recycled. Trade waste is waste is generated by shops, offices, or commercial places. Construction waste is found on residential premises. This waste includes batteries, empty paint and pesticide containers. Some of the household waste is recyclable. Industrial waste is waste that comes from industrial and manufacturing processes. Some of this waste is haza rdous. Intuitional waste is found in schools, hospitals, research institutions and public buildings. Medical waste is known as any solid or liquid waste which is generated in treatments. The Waste plan in my Community In my community the waste management plan for households is that waste is collected once a week. Businesses are different and get waste removed twice a week depending on how much waste is generated. Industrial waste is also collected once a week. It has been working effectively because the municipality has had no complaints and customers are happy with the system. The community also stays clean by means of the council collecting waste around bins so that the community will stay clean. Hazardous waste containers are also being provided and specialized companies deal with this waste. People that dump illegally get high fines. Public roads are being taken care of by litter being picked up by services five times a week. In the CBD litter gets picked up seven days a week. Free standing pole bins get emptied daily. Informal Settlements around my Community Some informal settlements where waste is not managed well is in the CBD, Hillbrow, New Town, Alexandra Township, and Jeppestown. The pollution comes in the form of dust from gravel roads, lack of clean running water, lack of regular refuse removal, broken and non-maintained sewerage pipes, absence of toilet facilities and ignorant littering. Due to the overcrowding of the informal settlements with migrants who are unemployed, and are not able to pay housing rent leads to a decay of flats and houses. In Alexandra some people still use the bucket system which increases the contamination from sewerage in the environment, and some people can get a wide range of illnesses. The organic waste attracts rodents and insects infestations. Poverty and lack of knowledge in these areas lead to littering, overflow of broken sewerage systems and unmanaged waste. A waste management plan for the informal settlements is that refuse is removed twice a week by means of bulk containers and street hawkers are issued with refuse bags weekly. â€Å"The metropolitan council wants a waste disposal strategy; identification of waste disposal sites, establishments, operation and control of waste disposal sites.† The community water supply and sanitation programs aims to ensure all South Africans have access to clean water. The metropolitan also wants to prevent invasion of industrial sites. Some solutions that can help reduce waste are: Waste Avoidance, Prevention and Minimization: system to ensure the appropriate design promotion, optimizing operating procedures and good house keeping for all waste generating processes. Forecasting potential situations in which accidents and spills can cause unscheduled waste emissions. Recovering, Recycling and Reuse: Reduction in the waste stream. Recycle materials such as taxes on waste or subsides for waste cycling, and also extraction and utilization of landfill gas. Treatment and handling: Ensuring that waste is appropriately treated and processed to their disposal in accordance with laws, regulations and guidelines. Storage and Final Disposal: Timely identification investigation and construction of environmentally and socially acceptable waste disposal facilities. New innovative ways of managing waste in disadvantaged communities are required. We can move towards collection by paying people to collect litter and involve the community in programs. We can improve the awareness to the public with regard to waste. Allow people living in informal settlements to regain their dignity by providing sustainable, affordable sanitation. Polokwane Declaration The aim of the Polokwane Declaration is to reduce waste by 50 % respectively by 2012 and have a plan for zero waste by 2022. In order to achieve their goals they must engage more closely in a realistic and practical manner. Conclusion In Gauteng waste management is lacking it appears there has been an increase in waste per year between 1998 and 2003. It also appears that Polokwane Declaration of zero waste remains optimistic. Hazardous waste has decreased as a result of improvement in industrial activities. Recycling initiatives are being adopted and are successful. The importance of the public awareness of waste and recycling should be made aware and action plans formulated.

Elements of Poetry and Essay Writing :: Education, Writing

I was surprised to find that I could use so many of the techniques that poets use in writing my own essays. For example, by choosing certain words, I can set the tone for the essay and demonstrate certain attitudes. Also, I can take advantage of several technical methods, such as abstractions, assonance, and figures of speech to make an essay more interesting. Further, I think it is important to try and understand the poets meaning behind their word choice. After analyzing the poems of John Donne, Anne Bradstreet, and Robert Frost, I will discuss how I think certain elements can be used in my own writing. Anne Bradstreet used words such as â€Å"loved†, â€Å"happy†, and â€Å"reward† to set a positive tone (963). The author’s attitude came across as grateful and appreciative. In contrast, Robert Frost chose to use words such as â€Å"perish†, â€Å"hate†, and â€Å"destruction†, which displayed a negative tone and attitude (1009). I never really gave this much consideration before, but I think I could use this technique in the future. By choosing the correct words, I can make sure the readers are interpreting my writing as I mean it to come across. I also discovered several technical methods that can be used in my essay writing. This is another area that I never really paid attention to. Sure, I have used some of them, but never knew what they were called or understood the full effect of them. Abstractions and several figures of speech were amongst some of the methods that were found. For example, â€Å"Batter my heart, three-personed God† (Doone 988), â€Å"To My Dear and Loving Husband† (Bradstreet 963), and â€Å"Fire and Ice† (Frost 1009), abstractions were used. Abstractions are words that we use to describe something that has no concrete reality (Charters 787). For example, in Doone’s poem, the author used words such as â€Å"weak† and â€Å"untrue† (989). Bradstreet also used this technique by using the word â€Å"love† (963). And finally, Frost’s word choice was cleverly utilized with using â€Å"desire† and â€Å"hate† (1009). These are also considered examples of figurative speech in that they use simile or metaphor in describing the subject (Charters 795). I feel by taking advantage of some of these techniques, I can make my essays more interesting for readers. To add, I found several figures of speech techniques such as metonymy, apostrophe, hyperbole and symbols were used in Anne Bradstreet’s poem â€Å"To My Dear and Loving Husband† (963).

English Law’s Approach to Same Sex Marriage Essay -- Law Legal Same Se

Introduction The phenomenon of same sex marriages is relatively new but is gaining popularity day by day. The notion has already been welcomed and enacted as law in different jurisdictions. However it lacks proponents within the UK legal system which is reluctant to allow such relationships to be regulated into marriages. There are two topical situations faced by English law which need to be considered: the right of same sex people to marry and the right of the transsexuals to marry a person of the opposite sex post their gender reassignment. Although English law stands in stark contrast compared to the other democratic states that have allowed same sex marriages. However there have been some recent developments in English law which demonstrate its approach towards the above two situations. This article will argue that the history of English marriage law is one in which the most provocative anxieties raised by transsexual and same sex spouses have been afforded considerable recognition. The first part of the essay outlines the reasoning of English law for non-recognition of same sex marriages celebrated overseas. While the second part points out the acknowledgement English law has afforded to transsexuals. Part-I Same sex marriages celebrated overseas Sec.11(c) of the Matrimonial Causes Act 1973 declares that a marriage would be void if the parties to it are not respectively male and female. Apparently this leaves no room for further argument. However there have been a number of occasions where the decision of the UK courts of not allowing recognition to same sex marriages has been challenged. A recent case decided in the High Court highlights the English stance on same sex marriages that took place outside the... ...: http://www. jstor.org/> Wright, W. 2006. The tide in favour of equality: same-sex marriage in Canada and England and Wales. International Journal of Law, Policy and the Family [Online]. 20(3). Accessed 12th December 2010]. Available from World Wide Web: http://www. oxfordjournals.org/> Legislation Civil Partnership Act 2004 Family Law Act 1986 Gender Recognition Act 2004 Matrimonial Causes Act 1973 Marriage act 1949 Cases Wilkinson v Kitzinger [2006] EWHC 2022 (fam) M v Secretary of State for Work and Pensions [2006] 2 WLR 638 Rees v UK (1986) 9 EHRR 56 Goodwin v UK [1996] ECHR 16 Corbett v Corbett [1971] P 83 W v W [2001] Fam. 111 Bellinger v Bellinger [2001] EWCA Civ. 1140 I v UK 35 Eur. Ct. H.R. 592 (2002) Parry v UK Appl. No. 4297/05 Websites http://www.wcl.american.edu http://www.dca.gov.uk/constitution/transsex/statement.html.

Human service Essay

Compile a list of the human service agencies in your city or state. Choose two agencies from your list. Research and study the available information for each agency, obtained from the agency’s Web site or other credible Internet sources. Search for information about how the agency determines needs and the demographic it serves. Refer to Appendix C for tips on where to find this information and Appendix G for other suggested Web sites. Compare and contrast the information you found for each agency, then answer the following questions in 200 to 300 words: †¢What needs do each agency meet and what demographic does each agency serve? What or who may have influenced the agency’s decision to meet the needs of this demographic group? †¢What differences have you observed between the ways the two agencies attempt to meet human needs? †¢How successful is each agency in meeting the needs of its demographic group? What challenges may be preventing the agencies from meeting certain needs? Well the two agencies that I looked up where food stamps (FI) and Medicaid. They are just about the same but they only go if you need them. If you have a low income family then you can get them both. But you have to make it on the charts. They go by the amount of money that you make and how many kids you have too. But you don’t have to have kids to get food stamps or Medicaid. These groups meet the needs of all the people but Medicaid only goes to the people that are older or have kids that are under the age 18 years old. The way I have found that they have made for the people is that they give people food in there house or they make sure that they have the health care that they need to live longer or even just get checked out for a cold. I think that the biggest challenges that they face is trying to find out who really needs it and who don’t need it. They have to look at each case very well and make sure that they don’t have any way to cheat the system any way. I believe that both of these thing make the government better and help use become a better united states all the way around.

Discover the affects of PH on the enzyme catalase

Catalase- This is an enzyme found in food such as potato and liver. It is used for removing Hydrogen Peroxide from cells. Hydrogen Peroxide is the poisonous by-product of metabolism. It speeds up the decomposition of hydrogen Peroxide into oxygen and water. It is able to do this because the shape of its active site matches the shape of Hydrogen Peroxide molecule. This type of reaction where a molecule is broken down into smaller pieces is an ANABOLIC REACTION. BACKGROUND INFORMATION ON ENZYMES: Enzymes- Enzymes are complex 3-D globular proteins, some of which have other associated molecules. Enzymes are a catalyst which alters the rate of chemical reaction without itself undergoing a permanent change, and therefore can be used over and over again. Enzymes help reactions speed up which would otherwise take place very slowly. While the enzyme molecule is relatively larger than the larger than the substrate molecule it acts upon, only a small part of the enzyme molecule actually comes into contact. This region is called the ACTIVE SITE. The active site of an enzyme is the region that binds the substrate and contributes the amino acid residues that directly participate in the making and breaking of chemical bonds. However, all enzymes operate only on a specific shape and therefore fit only complementary locks, so only substrates of a particular shape will fit the active site of an enzyme. Prediction I predict that as the PH increases the activity of enzyme increases until the optimum PH is reached. Catalase optimum ph is around 6-7.after that the enzyme will be denatured. Hypothesis The enzyme will have an optimum pH of around neutral. Either side of the optimum pH will have relatively high rates of reaction or far away from the optimum pH will have a low rate of reaction. The enzyme catalase is found in many tissues including potato and liver. It is important because it breaks down the hydrogen peroxide formed in metabolism. Hydrogen peroxide is toxic and if it were not broken down it would kill the cells. As it does this, it liberates carbon dioxide that can be collected. CHEMICAL EQUATION: 2H2O2 ——————-> 2H2O + O2 I also hypothesize that the catalase activity will be highest with the sample of potato comparing to the apple. Variables The factors, which will have an affect on the enzyme activity, will be: * Temperature * Concentration of enzymes * pH The variable in which I will be using to investigate the enzyme activity is the temperature. The rest of the variables will be kept constant and only the temperatures will be changed. Apparatus To test how the PH affects the rate of reaction, I will use the following apparatus: * Gas syringe through bung * Potato * Hydrogen Peroxide * Stop Clock * Cork borer * Scalpel * water Beaker-250 cmà ¯Ã‚ ¿Ã‚ ½ * Delivery Tube * Ph 3,5,7,9 * 5 cmà ¯Ã‚ ¿Ã‚ ½ or 10 cmà ¯Ã‚ ¿Ã‚ ½ plastic syringe with end cut off * measuring cylinder * conical flask * White tile * wax * Test tubes * Test tube rack * Safety equipment; goggles, lab coat, gloves Alternative: Use yeast, broad beans or liver, instead of potato and apple. Method 1. Measure out 5cm3 of potato into a conical flask 2. Measure out 10 cm3 of buffer solution into a separate container and mix it with minced potato. 3. Measure out 5cm3 volume of hydrogen peroxide in syringe. 4. Fill a tub with water. 5. Completely immerse a measuring cylinder in the water making sure to release all air bubbles in the cylinder and keep underwater. 6. Position the cylinder upright ensuring the open end remains underwater and clamp securely 7. Add the hydrogen peroxide to the potato and place bung on conical flask whilst starting timer. 8. Run experiment for 5 minutes taking readings every 30 seconds by noting the amount of gas at top of cylinder (at meniscus) 9. Repeat the experiment with different ph. Justification of method: I have chosen to use this method because it is safe, efficient and accurate. I feel that it will help me to obtain reliable results. Risk Assessment * Hydrogen peroxide is a dangerous substance. It can cause serious injury to the eyes and skin. It is therefore necessary that goggles be used for eye protection. In addition, eye irrigation equipment should be readily available in case of an emergency. * The working area must be clean, tidy and dry. Make sure there is no obstacle in the working area so that you can easily move around as. This allows you to perform the experiment safely and unimpeded care should be taken to ensure that liquid is not spilled onto the floor to cause slippage. Result table Time(s) Oxygen gas collected (cm3) Ph 3 ph 5 ph7 ph9 30 1.5 1.5 0.5 1.5 60 1.5 3.0 1.5 2.0 90 1.5 5.0 2.0 2.0 120 1.5 7.0 5.65 2.0 150 1.5 8.3 10.3 2.0 180 1.5 9.0 14.35 2.0 210 1.5 10.0 17.35 2.0 240 1.5 11.1 20.15 2.0 270 1.5 13.6 24.15 2.0 300 1.5 14.0 31.15 2.0 These results clarify that the optimum ph for catalase is 7 which supports my prediction. At the lowest ph 3, less oxygen was released, measuring a slower rate of reaction. My background information explains this. The enzyme don't work as it is neared extreme PHS. This is because its shape would have been change slightly; means the active site may not fit into the substrate any more. Further investigation: If this investigation were to be done again, I would take all results myself and use my own interpretation, thus gaining more reliable results. I will know how much potato to measure out for each experiment and also I will make sure that the other variables are kept constant. I have taken the same amount of each, keeping them constant. This would give me clearer results to aid me in my understanding as to how ph can affect the activity of catalase.

Water Assisted Injection Moulding: a Study on the Influence of Melt and Process Parameters on the Residual Wall Thickness and the Occurrence of Part Defects for Pa6.

KATHOLIEKE HOGESCHOOL LIMBURG Departement Industriele Wetenschappen en Technologie Water Assisted Injection Moulding: A Study on the Influence of Melt and Process Parameters on the Residual Wall Thickness and the Occurrence of Part Defects for PA6. Gielen Bjorn, Heynickx Lien, Van den Brink Dominique, Vandersteegen Jochen Water Assisted Injection Moulding: A Study on the Influence of Melt and Process Parameters on the Residual Wall Thickness and the Occurrence of Part Defects for PA6. Gielen Bjorn, Heynickx Lien, Van den Brink Dominique, Vandersteegen Jochen Received 7 March 2011 Abstract Although water assisted injection moulding is a relatively new and advanced technique to produce hollow parts, several problems which reduce the product quality can occur. Namely, water inclusions in the wall, severe fingering and double wall defects reduce the product part stiffness. This study investigated the effect of the process parameters water volume flow rate, water injection delay time and melt temperature on the part defects to obtain a better understanding of the formation of these part defects. The effect on the residual wall thickness and the weight of the products was also investigated. Three materials were used: two polyamides and one polypropylene as a reference. The experiments were carried out on an injection moulding machine equipped with a water-injection unit to produce hollow handles. The parts were weighed before and after drying, their wall thickness was measured and their percentage of defects was calculated in order to determine the influence of the processing parameters. IR images and pressure profiles ware also used to investigate possible detection methods for part defects. It was found that all the investigated parameters have a significant influence on the residual wall thickness and part defects. Their ‘ideal’ settings depend on the material and the desired properties since small wall thicknesses and few part defects do not always correspond. IR images can give an indication for the presence of defects, but the internal structure of the surface can not be examined using this technique. Key words: water assisted injection moulding, polyamide, processing parameters, residual wall thickness, fingering, double wall 1. 1. Introduction The development of the water assisted injection moulding (WAIM) technique has led to a breakthrough in the manufacturing of hollow or partly hollow plastic parts, which is not possible with the conventional injection moulding process [1] [2]. These hollow parts are characterised by the lighter weight of the products, relatively lower resin costs per part and less shrinkage and warpage compared to conventional moulded products [3]. Several techniques are available for the production of hollow parts. Two of the most important techniques for hollow parts are gas assisted injection moulding (GAIM) and water assisted injection moulding (WAIM). The principle of water assisted injection moulding is basically similar to gas assisted injection moulding, but the use of water has some interesting advantages over gas assisted injection moulding such as a shorter cycle time and an average smaller residual wall thickness of the products. This is due to the fact that the thermal conductivity and the heat capacity of water are respectively 40 and 4 times greater than those of gas [1], providing a better cooling of the part and therefore a faster production. Water assisted injection moulding is better to mould larger parts with a smaller residual wall thickness. Another advantage of water assisted injection moulding is the absence of the foaming phenomenon in the internal surface which can occur by using gas assisted injection moulding , since water does not dissolve or diffuse in the polymer melt during injection moulding. Disadvantages of water assisted injection moulding are part defects such as fingering and double wall arising in the internal surface. Also, the process is more complex so experience with conventional injection moulding is no guarantee for understanding water assisted injection moulding. The control f the process is much more critical, the design of the mould is more complicated and requires more knowledge of the dynamic interaction between the polymer and the filling water [4]. In addition, new water related processing parameters (water pressure, water injection delay time, water temperature, †¦ ) are involved and require proper adjustment [5]. The technology can be used to mould a large variety of polymers, includi ng glass fibre reinforced composites. Liu [6] reported the successful moulding of PP, PE, ABS and glass fibre filled polyamide 6 (PA6) composites with water assisted injection moulding. According to our investigation, few researchers have described the moulding of pure polyamide 6 with the water assisted injection moulding technique. By understanding the water assisted injection moulding process for this polymer, one is able to optimize the production and improve the product quality of PA6 parts. The water assisted injection moulding process can be applied in four variations [1] [6], which differ by the amount of injected polymer and introduction and evacuation of the water. In the short shot moulding process the cavity is first partially filled with polymer and in the next sequence, highly pressurised water is injected into the polymer core. The pressure is maintained during the cooling sequence to minimize the shrinkage and to further cool down the part. After cooling, the water is evacuated and the part is ejected. This technique is useful for thick parts, but the important limitation is the switchover mark on the surface [7]. This limitation can be eliminated by using the full shot moulding process in which the cavity is first completely filled with polymer. Next, the injection of water pushes the melt into a cavity positioned outside the cavity of the product. This overspill cavity arises by pulling back a core to enlarge the mould cavity for the overspill polymer which has to be removed from the product afterwards. Full shot moulding makes it possible to mould parts with a more uniform residual wall thickness through the end of the part in comparison to short shot moulded parts. Michaeli et al. [6] stated that the melt-push-back process is also capable to produce parts with a more uniform residual wall thickness distribution. In this process the water is injected in the reversed direction of the polymer injection and pushes the excess of melt back into the plasticizing unit. Finally, the core-pulling process uses a series of steel cores that are pulled back during water injection to increase the cavity volume and the product volume. This method produces parts with more uniform internal profiles in comparison to the former mentioned techniques. The investigated polymer, polyamide 6, is a semi-crystalline material that is classified as an engineering plastic. Beneficial properties of polyamide 6 over a wide range of temperatures and humidity are its high strength, high stiffness and toughness, good wear and abrasion resistance, low coefficient of friction and good chemical and electrical resistance [8], [9], [10], [11]. Further modification can be obtained by adding additives like fillers and plasticizers. Fillers achieve a better strength and stiffness, plasticizers cause higher toughness [12], [13]. Modification of the molecular weight has also a distinguishable influence on the polymer properties. The main drawback of polyamide 6 is the high moisture absorption affecting the rheological properties and deteriorating the processability. High moisture absorption causes part defects and results in a bad internal surface quality reducing the stiffness of the end product [14], [15], [16]. The absorbed water in the polymer has two important roles. Firstly, the water molecules act as plasticizers reducing the hydrogen bond interactions between the polyamide chains. Secondly, due to the hygroscopic nature of polyamide 6, the absorbed water influences the condensation reaction equilibrium depending on the initial moisture content [17], [18]. If the moisture content is less than prescribed thermodynamically, the reaction proceeds towards further condensation and an increase in molecular weight, increasing the viscosity exponentially. If the moisture content is higher than determined by the equilibrium, a hydrolysis reaction occurs. This causes a decrease in viscosity as well as degradation of the polymer. To properly process polyamide 6, the pellets are preferably dried to small moisture levels. Possible part defects that may occur in water assisted injection moulding are fingering and double wall. Liu and Lin [19], [20] investigated the problem of fingering in water assisted injection moulded composites. The fingering phenomenon comprises the non-uniformly penetration of water bubbles or steam into the polymer wall outside the designed water channels causing the formation of finger-shaped branches and small cavities in the polymer wall, which lead to a bad internal surface quality and a reduced part stiffness of the end product. Fingering depends on the dimension of the part: thick parts usually exhibit less fingering pattern than thin parts. Three factors might affect the formation of fingering. The first one is shrinkage of the polymer during cooling. During post-filling, the polymer undergoes volumetric shrinkage allowing water to penetrate into the parts. The more the polymer shrinks, the more water will penetrate into the part and causes fingering. However, this statement is in contradiction with the statement that thick parts exhibit less fingering, so research is necessary to investigate which conclusion is relevant for PA6. Shrinkage also depends on the crystallinity of the polymer. PA6 is a crystalline polymer and thus expected to show more shrinkage than an amorphous polymer. Also, water injection moulded parts show more fingering than gas injection moulded parts since water has a higher cooling capacity than gas and has a higher cooling rate of the polymer. This leads to a greater non-uniform temperature distribution in the polymer material which worsens the uniformity of water penetration inside the parts, resulting in fingering [20]. This is equal to the statement that more shrinkage leads to more fingering. The second factor is the viscosity of the polymer melt. During water injection, water follows the path with the least resistance. While the water enters into the mould cavity, it cools the polymer melt and increases the viscosity. It then becomes more difficult for the water to penetrate into the core of the parts. The third factor is the flow resistance in the channel and in the polymer. The higher the flow resistance in the channel and the lower the flow resistance in the polymer, the more water fingering will be induced. The researchers [19] concluded that water fingering worsens when a combination of a higher water pressure, a smaller melt short shot size and a shorter water injection delay time is used. Other parameters which need to be paid attention to are the temperatures of the melt, the mould and the water. Increasing these parameters decreases the cooling rate and the viscosity and results in more fingering because it is easier for water to penetrate in the part. Another possible part defect in water assisted injection moulding is double wall [22]. Double wall is the appearance of a second polymer wall inside the hollow product which deforms the wall significantly. During the water hold time water inclusions develop in the wall. The double wall is caused by the pressure drop after the water hold time. The water in the inclusions becomes steam and expands the internal material surface causing a second wall in the polymer. Two important parameters are responsible for the forming of double wall. The first parameter is the water hold time which should be minimized in order to eliminate double wall. Increasing the water hold time compensates the shrinkage in the wall but enlarge the water inclusions in the wall worsening the double wall. The second parameter is the volume flow rate. Increasing the volume flow rate causes more double wall because more water penetrates in the polymer forming water inclusions which expand into double walls after the water hold time. There is not much known about the phenomenon of double wall. A lot of investigators do not even make a difference between fingering and double wall and characterize it as the same part defect. Hollow parts are mainly characterized by their residual wall thickness that should be minimized in order to obtain a good product quality with minimal defects. A decline in wall thickness is mainly obtained by choosing water assisted injection moulding instead of gas assisted injection moulding [4]. However, Michaeli et al. [22] concluded that in some cases gas assisted injection moulding yields parts with a smaller residual wall thickness. Several process settings can be applied for water assisted injection moulding, each having an influence on the residual wall thickness. Huang and Deng [23] concluded that besides the short shot size there are two other main parameters affecting the residual wall thickness in polypropylene samples. The first parameter is the melt temperature. Increasing the melt temperature leads to reduction of the solidified layer thickness and thus to a decrease in wall thickness. The second parameter is the water injection delay time. When increasing the water injection delay time, the residual wall thickness exhibits an increment because the solidified layer of the melt becomes thicker. Liu and Wu [24] researched the effect of the injection pin on the residual wall thickness distribution. In their research they concluded that a pin consisting of a sintered porous surface can mould large parts with a more uniform residual wall thickness distribution. Application of this high flow rate pin could significantly improve the product quality in terms of smaller wall thickness. The non-uniformity of the residual wall thickness distribution usually occurring in curved product sections, was found to be less in water assisted injection moulded parts than in gas assisted injection moulded parts. Fluids try to follow the path with the least resistance; this is the shortest path. However, water has a higher mass inertion than gas and therefore gives a better concentricity of the residual wall thickness over a cross-section. The uniformity of the residual wall thickness could be improved by adopting different mould temperatures [25]. In order to mould PA6 parts with high product quality using WAIM, one has to apply the optimal settings to reduce the part defects (fingering and double wall) and decline the residual wall thickness. The water injection delay time influences fingering and the residual wall thickness. A shorter water injection delay time causes a smaller residual wall thickness but results in more fingering [19] [23]. The water volume flow rate is an important parameter on fingering, double wall and the residual wall thickness. A higher water volume flow rate gives a smaller residual wall thickness but more fingering and double wall [21]. The melt temperature has an influence on fingering and the residual wall thickness. Increasing the melt temperature leads to a smaller residual wall thickness but to more fingering [19] [20] [23]. Further experiments in this research focuses on the influence of the water injection delay time, the water volume flow rate and the melt temperature on the residual wall thickness and the occurrence of part defects for PA6, using a design of experiments. 2. Experimental procedure 2. 1 Materials To investigate the residual wall thickness and part defects like water inclusions, fingering and double wall of water assisted injection moulded products, two polyamides (PA F223-D and PA F130-E1 from DSM) and a polypropylene (PP 400-GA05 from Ineos) were used. The melting and crystallization temperature of the materials were measured with differential scanning calorimetry (TA Instruments 2920 CE). The viscosity was measured with a capillary rheometer (CEAST Smart Rheo 2000 twin bore). The complex viscosity, storage and loss modulus were measured with a parallel plates rheometer (AERES strain controlled rheometer). The measurements show that the zero-shear viscosity of the polypropylene is higher than those of the polyamides. PA F223-D has a higher zero-shear viscosity than PA F130-E1. This indicates that the molecular weight is higher for polypropylene than for PA F223-D and that PA F130-E1 has the lowest molecular weight. The decrease in viscosity at higher shear rates occurs at lower frequencies for polypropylene in comparison with the polyamides. This indicates a higher molecular weight distribution for polypropylene than polyamide. PA F223-D has a higher molecular weight distribution than PA F130-E1. . 2 Moulded parts The part that is moulded for this experiment is displayed in figure 1. It contains four curved sections varying in radius of curvature. The polymer and water enter the cavity at the bottom side. Water enters when a movable injector is pushed forward and a core at the end of the part is pulled allowing the polymer to be removed out of the inner core of the part. Figure 1: moul ded part containing four curved sections 2. 3 Equipment The injection moulding was executed with an Engel 80-ton injection moulding machine ES 330H/80V/80HL-2F. The dimensions of the machine are 4,80 m x 2,22m x 2m. The single screw diameter is 50 mm and the plastification unit can operate with a maximum injection rate of 152 cm? /s. A volume flow rate controlled water injection unit brings the water into the mould. It can operate with a maximum water volume flow rate of 30 l/min, delivered by a maximum pressure of 200 bar. During the tests a maximum pressure of 160 bar was applied. Three pressure sensors type Priamus are localized in the mould. An IR-camera type FLIR is used to observe the temperature distribution over the produced handles after moulding. The IR-images were used to compare with the internal section to discover the cause of part defects, because water in the product gives lower temperatures on the IR-image. The dried hollow polymer handles are sawed in lengthwise direction with a band saw. The band saw is type Metabo bas 260 swift. After sawing the hollow polymer handles, the internal section were scanned with a scanner type Cannon FG17500. A metric software 8. 01 plus was applied to analyze the surface quality of the polymer. With the aid of the software, the surface area of the wall and the part defects can be determined. . 4 Method DOE procedure The experiment investigated four processing parameters that were selected after a preliminary literature study, assuming these will have a significant influence on the residual wall thickness and part defects. These parameters are the water volume flow rate, water injection delay time and melt temperature. Using the design of experiments approach, each parameter was measured on a low and high setting; making this a 23 experiment. In addition three centre points were measured bringing the total number of experiments to 11 for each material. Response functions were constructed for residual wall thickness, weight and defects. The significance of each parameter was checked by comparing its effect to the deviation of the centre points, neglecting the parameter if its effect is smaller than the centre point deviation. Experimental procedure After steady state was reached, five shots were produced for each setting of water volume flow rate, water injection delay time, melt temperature. For each last shot of an experiment, a print screen of the pressure evolution and an IR-image was taken. During the process the following parameters were measured: * real injection time; * absolute shot volume; * real cushion; * flow number. After moulding, the parts were dried with compressed air to remove water of the inner- and outer surface of the product. Then the injection side of the product was removed and both halves were weighed. The sawed injection product was controlled on the presence of defects giving a first indication of the quality of the product. Afterwards the handle was dried in a furnace for 44 hours on 90  °C. After drying, the handles were weighed again obtaining the weight of the water inclusions in the product wall. Three representative handles were sawed in lengthwise direction and the breams were removed. The handles were scanned to determine the residual wall thickness and the percentages of defects like water inclusions, fingering and double wall. Table 1: Processing variables and settings used for the experiments | A| B| C| Process parameters| Water volume flow rate (l/min)| Water injection delay time (s)| Melt temperature ( °C)| -1| 10| 1,5| 240| 0| 20| 5| 260| 1| 30| 8,5| 280| A| B| C| Experiment| Water volume flow rate (l/min)| Water injection delay time (s)| Melt temperature ( °C)| 1| 20| 5| 260| 2| 10| 1,5| 240| 3| 30| 8,5| 240| 4| 30| 1,5| 240| 5| 10| 8,5| 240| 6| 20| 5| 260| 7| 30| 8,5| 280| 8| 10| 1,5| 280| 9| 10| 8,5| 280| 10| 30| 1,5| 280| 11| 20| 5| 260| Table 2:Experiment schedule for parameter settings The part defects are calculated as follows: The parameters whic h have an influence on the product quality are the water volume flow rate, the water injection delay time and the melt temperature. The tested parameter settings are presented in table 1. A code using -1 for low, 0 for center point and 1 for high setting is applied. The combination of parameter settings (Table 2) are determined using design of experiments. Using the design of experiments method makes is possible to obtain a better understanding of the formation of the defects and the influence of the processing parameters. Eventually a moulding window will e determined in which the defects are minimized. 2 Results and discussion 3. 1 Effect of water volume flow rate Figure 2 shows the effect of the water volume flow rate on the residual wall thickness and the product defects. Following paragraphs discuss these diagrams. Influence on the residual wall thickness and product weight Considering the residual wall thickness, polypropylene has a smaller residual wall thickness than the residual wall thickness of polyamide for all experiments. Polypropylene has a higher molecular mass, causing a wider water flow front. The higher molecular weight distribution (MWD) of PP causes a block velocity profile of the water resulting in a higher velocity on the polymer- water interface. The higher velocity causes a higher shearing and consequently a lower viscosity, resulting in a higher removal. This results both in a smaller residual wall thickness and a lower part weight. The density of polypropylene is lower compared to compared to the density of polyamide, which is also an explanation for the lower weight of product. Regarding the product weight and the residual wall thickness, the two polyamides do not differ much and correspond to each other. This is probably due to the small difference in molecular mass and molecular weight distribution. Figure 2: Effects of water volume flow rate on water inclusions, residual wall thickness, fingering and double wall The residual wall thickness of polyamide seems not to be significantly affected by the water volume flow rate. Polypropylene however, tends to increase in residual wall thickness by application of a lower water volume flow rate. These results correspond to the suggestion that a higher water volume flow rate gives a smaller residual wall thickness, as was found in preliminary literature study. In general a material with a high MWD, like PP, will be more influenced by the flow rate than other materials like polyamides. Influence on water inclusions In general the water inclusions tend to decline when the water flow rate increases. A higher flow rate provides more shearing, giving a lower viscosity. The water can easily remove the internal polymer and does not penetrate into the walls of the polymer. PP completely corresponds to this theory, but the polyamides show an irregularity during high flow rates. this can be explained by the strong variations in injection time and a chance in the water flow profile to a profile called recirculation flow. It pushes the water into the walls causing an increase in water inclusions. The strong variations that occur with PP are probably caused by its high MWD. This property also played an important role regarding the RWT. Influence on fingering Fingering is probably caused by differential shrinkage, making a material with a high degree of crystallization like polypropylene vulnerable to this defect. The defect diminishes at high flow rates where the wall thickness is smaller, making it more difficult for polypropylene to shrink and for fingering to occur. PA F130-E1 exhibits a low variation in fingering in comparison to the other materials. This material is not in its area of shear tinning when working with low flow rates, resulting in a constant viscosity and residual wall thickness. Because of this low variation in RWT and corresponding shrinkage with changing flow rate the effect of the flow rate will be very small. In general materials with a high MWD and MM like PP show more fingering than materials with low MWD and MM like PA F130E1. PA F223D will take a intermediate position taking into account that its centre point is not completely representative. This trend for fingering is visible for all parameters. Influence on double wall The influence of the flow rate shows an overall optimum profile. Low and high flow rates cause more double wall than an intermediate setting. A first theory relates this effect to the pressure inside the part. Low flow rates exert low pressure on the polymer melt and the polymer will not form a rigid layer, making it possible for the water to penetrate into the polymer walls. High flow rates cause high pressures inside the part forcing the water into the walls. The second theory is based on the tendency of water to follow the ath of least resistance and can only explain the effect with low flow rates. The low rate will cause almost no shear stress inside the polymer so it will not reach the shear tinning area. The polymer will not easily be pushed back by the water and the water will penetrate the walls where the resistance is much lower. The effect of the water volume flow rate on double wall is the same as for water inclusions, which is explained by the rel ation between water inclusions and double wall. Water inclusions can grow during the water hold time, collapsing into double walls in the product after pressure removal. The higher double wall defects for PAF130-E1 in comparison to PA F223-D are probably caused by the difference in molecular mass. PA F130-E1 has a lower molecular mass and thus a less viscous melt resulting in a more easily penetrable material. Another noticeable result is that of the investigated materials, PA F223-D shows high part defects but relatively the smallest double wall defects. PP, the material with the highest MM shows more double wall at high flow rates for which no explanation can be found. 3. 2 Effect of the water injection delay time Figure 3 shows the effect of the water injection delay time on the residual wall thickness and the product defects. Following paragraphs discuss these diagrams. Influence on the residual wall thickness and product weight A shorter water injection delay time causes a decline in the residual wall thickness and weight of product for polyamide and polypropylene, as was predicted by literature. When the water injection delay time is short, the polymer is still hot and has a low viscosity, giving the water the opportunity to hollow out the polymer more. A higher water injection delay time causes a higher residual wall thickness and weight of product because the melt viscosity increases. The residual wall thickness is higher for polyamide than for polypropylene, for the same reasons as discussed under the previous paragraph. Influence on water inclusions An increase in delay time is accompanied by an increase in viscosity that makes it more difficult for the water to penetrate into the walls. However, if the viscosity is too high, the water can also be forced into the walls, which explains the slight increase in water inclusions for PP 400-GA05 and PA F130-E1. Figure 3: Effects of the water injection delay time on water inclusions, residual wall thickness, fingering and double wall The strong decrease in water inclusions that occurs with polypropylene is caused by the high heat capacity of this material making it cool down faster than the polyamides and increasing its viscosity faster. PA F130-E1 shows less defects in comparison with PA F223-D, probably caused by its strong temperature related viscosity. During the delay time the viscosity strongly increases, making it more difficult for the water to penetrate. Influence on fingering Increasing the delay time increases the residual wall thickness and should result in a higher chance of fingering. In general this trend can be observed from the diagrams. More fingering occurs within PP 400 GA05 caused by its higher degree of crystallization. Furthermore, this polymer is processed at much higher temperatures than its melting point, leading to further shrinkage and corresponding fingering. The presence of defects during processing with long delay times is caused by a greater residual wall thickness, which leads to more differential shrinkage. Processing with short delay times increases the presence even further, but no plausible statement can explain this. Therefore further research will be necessary. The results for the centre point of PA F223-D are probably not representative, since it is based on a single experiment of three shots. Influence on double wall The water injection delay time shows an overall optimum profile, which can be related to the shift of the rigidity in time, caused by the temperature drop over time. Production with a short delay time will push water inside the low viscosity polymer which makes it easy for the water to penetrate. Increasing the delay time also increases the viscosity and thus the rigidity of the polymer making it harder to penetrate the walls. However, if the viscosity is too high, the water will also be forced into the walls. PA F130-E1 shows more double wall because its viscosity is highly temperature related. Longer delay times will lead to larger temperature drops and a corresponding increase in viscosity. 3. 3 Effect of the melt temperature Figure 4 shows the effect of the melt temperature on the residual wall thickness and the product defects. Following paragraphs discuss these diagrams. Influence on the residual wall thickness and weight of product Considering the residual wall thickness, polypropylene has a lower residual wall thickness and weight of product compared with polyamide for all experiments. This might be due to the higher molecular weight and the higher molecular weight distribution of polypropylene. The higher molecular weight distribution shows a square blocked velocity profile causing a higher velocity on the wall and a higher shearing. This results in a lower viscosity and therefore more removal of the polymer decreasing the residual wall thickness and weight of product. PA F130-E1 and PA F223-D are quite similar and do not differ much in residual wall thickness and weight of product. Increasing the melt temperature leads to a smaller residual wall thickness as was suggested by literature, because a higher melt temperature makes the polymer less viscous so more polymer can be removed by the water. The residual wall thickness of PP decreases from 240 °C to 260 °C but increases to 280 °C. The increase of the melt temperature is difficult to explain and is possible a unreliable point. In fact, also for polypropylene a decreasing tendency is remarkable. Influence on water inclusions There is a trend towards higher water inclusions when a higher melt temperature is applied. This parameter thus shows the opposite effect of the delay time. PA F130-E1 differs from the other materials, probably due to the strong variations in injection time during production. Furthermore this polymer shows a lot of internal heating (viscous heating) when Figure 4: Effects of the melt temperature time on water inclusions, residual wall thickness, fingering and double wall high pressure is exerted, leading to a drop in viscosity. This effect usually appears in combination with low melt temperatures where the polymer has a lot of pressure to bear. So low temperatures will lead to viscous heating and therefore to high intern temperatures. The water can then easily enter the walls of the polymer due to the lower vicosity. Influence on fingering When processing the material at low temperatures, the material will have to shrink less and thus less fingering will occur. This trend is clearly visible for the polyamides, taken into account that the centre point of PA F223-D is not representative. In fact, the effects should show an opposite effect from the delay time, but this is not clearly noticeable. Further research will be necessary to explain these irregularities. Influence on double wall A higher melt temperature causes an overall increase in double wall defects for all three materials. This effect is related to the viscosity of the polymer which varies with temperature. High temperatures will lead to a decrease in viscosity making the polymer more penetrable for water. Another theory is based on the water flow profile inside the polymer. Higher temperatures usually correspond to smaller residual wall thicknesses changing the flow profile into a recirculation flow where water will be pulled into the walls. 3. 4 Comparison results of response functions and graphical tendencies Table 3 gives an overview of the best parameter settings to reduce each part defect and the total defects for each material, comparing the results of a response function (before /) and the graphics in figure 1/2/3 (after /). The response functions were constructed using the design of experiments method. Regarding the defects, only one response function was made which ncludes both fingering and double wall. Ideal settings according to response functions Using the response functions several conclusions can be made for the ideal settings of the parameters. A high water injection delay time creates less water inclusions in both polyamides. In addition, the polyamides show the same optimal settings of all parameters for the residual wall thickness. A low water volume flow rate is beneficial for the reduction of the residual wall thickness, fingering and double wall. Other settings conflict to give minimal part defects in polyamide. In general, PA F223-D has minimal part defects for a low water volume flow rate, a high water injection delay time, and a low melt temperature. PA F130-E1 requires a low water volume flow rate as well, but a low water injection delay time and a high melt temperature. The optimal settings for the minimal percentage water inclusions, fingering and double wall are highly contradictory for polyamide and polypropylene. PP 400-GA05 requires a high water volume flow rate for a smaller residual wall thickness but the other parameters have the same optimal settings for the residual wall thickness as polyamide 6. The water volume flow rate and the water injection delay time do not influence fingering and double wall significantly, so no conclusions can be made for these settings to obtain minimal fingering and double wall. If also the water inclusions and the residual wall thickness are taken into account, PP400-GA05 shows minimal part defects for a high water volume flow rate, a low water injection delay time and a low melt temperature. There can be concluded that for all three materials the best parameter settings for residual wall thickness, fingering and double wall are not the same. Since other effects may probably have an influence on the materials, further investigation will be necessary. Ideal settings according to previous diagrams The following best parameter setting are based on the previous graphics. Regarding the residual wall thickness, the best parameters for PP and PA F130D are an intermediate water flow rate, a low water injection delay time and a high melt temperature. For PA 223D, a low water flow rate is required and the other parameters are the same. For fingering, a high water volume rate, an intermediate water injection delay time and melt temperature give the best results for PP. PA F223D gives the best results for a low water volume flow rate and water injection delay time and an intermediate melt temperature. PA F130E1 in contrary, the best parameters setting are a high water volume flow rate and a low water injection delay time and melt temperature. The parameters setting are different for the three materials and show a lot of irregularities. Considering double wall, the best parameter settings are a low water flow rate, water injection delay time and melt temperature. For both polyamides the best parameter setting are equal, an intermediate water flow rate, delay time and melt temperature. For the water inclusions, the best results were observed for a high water volume rate and an intermediate water delay time and melt temperature. PA F223D shows less water inclusions when an intermediate flow rate, a low delay time and in intermediate melt temperature is used. PA F130E1 in contrary gives the best results for a intermediate flow rate and delay time and a low melt temperature. Ideal settings for PA F223-D| | Optimal setting| Response factor| Target figure| Water volume flow rate| Water injection delay time| Melt temperature| Water inclusions| Low| High/High| High/High| Low/Low| Residual wall thickness| Low| Low/High| Low/Low| High/High| Fingering and double wall| Low| Low/High| High/Low| Low/Low| Total| | Low/High| High/Low| Low/Low| Table 3: Overview of ideal settings for the materials for each part defect Ideal settings for PA F130-E1| | Optimal setting| Response factor| Target figure| Water volume flow rate| Water injection delay time| Melt temperature| Water inclusions| Low| Low/High| High/High| High/Low| Residual wall thickness| Low| Low/High| Low/Low| High/High| Fingering and double wall| Low| Low/High| Low/Low| Low/Low| Total| | Low/High| Low/Low| High/Low| Ideal settings for PP 400-GA05| | Optimal setting| Response factor| Target figure| Water volume flow rate| Water injection delay time| Melt temperature| Water inclusions| Low| High/High| Low/High| High/Low| Residual wall thickness| Low| High/High| Low/Low| Low/High| Fingering and double wall| Low| -/High| -/Low| Low/Low| Total| | High/High| Low/Low| Low/Low| Once again, here can be concluded that the best parameter settings for residual wall thickness, fingering and double wall are not the same. Since other effects may probably have an influence on the materials, further investigation is necessary. . 5 Detection of part defects 3. 5. 1 IR-images IR images were tested if they can be used to obtain an indication of the quality of the product. This could be an important tool during production as it can deliver information about the internal structure without damaging the part. It was found that a uniform heat distribution in the part usually corresponds to few defects in the walls. The polymer equally shrinks and cools, causing no stress in the walls which could lead to defects. Figure 5 shows the section and an infrared image of a hollow part from PP 400-GA05 without defects. The corresponding IR picture shows no significant Figure 6: Scan and IR image of PP 400-GA05 product with defects irregularities in the heat distribution. The areas where the part has a higher or lower Figure 5: Scan and IR image of PP 400-GA05 product without defects temperature than the bulk are caused by respectively larger and smaller residual wall thicknesses. Small defects like fingering can occur where colder areas are completely surrounded by larger hot material making it isolated cold regions. If the cold area is gradually spread throughout the part and is therefore no isolated region, fingering is often not present. The isolated colder regions are most likely filled with water which provides more efficient cooling than the rest of the part, resulting in uneven shrinkage and corresponding fingering cavities. Large defects like double wall are often present where a relative large cold area spreads throughout the complete section and is surrounded by hot material. These defects are also likely to occur in regions with higher temperature than the rest of the part. However, the latter can also correspond with a larger residual wall thickness and is thus not conclusive for the presence of double wall defects. Figure 6 shows a part with double wall defects and the corresponding infrared image where the isolated hot (white) and cold areas (yellow) are indicated. The texture of the internal surface can not be judged with an infrared image. PA F130-E1 tends to show a rougher surface in regions with a much lower temperature, but not all parts share this conclusion. Within the other materials a rough surface does not corresponds with lower temperature areas thus the infrared does not delivers clear information about this property. 3. 5. 2 Pressure and injection rate profiles The pressure profiles and the injection rate during the injection of the melt can be used to declare some of the defects shown in the different polymer samples. The injection rate was set on 45 mm/sec and the maximum feasible pressure of the WAIM equipment was 160 bar. For the polyamides, this maximum pressure was exceeded in some cases during filling of the mould. This caused a temporary reduction of the injection rate and possibly some of the part defects of polyamide. Polypropylene does not show this trend because it has a lower flow number than PA. Figure 7 shows an example of this phenomenon in PA F223-D. In general it can be concluded that when the temperature increases the measured pressure and the flow number decrease. This reduction in pressure can be explained by the fact that the viscosity of the material will be lower at a higher temperature, so the polymer can flow easier and less pressure has to be applied. However it is not guaranteed that an irregularity in the injection profile of the polymer results in problems during water injection. This experiment was to limited to make clear conclusions about this effect. Figure 7: Pressure and injection rate profile for PA F223-D (green=pressure, blue=injection rate) 4. Conclusions 4. 1 General This report has studied the influence of melt and processing parameters on the residual wall thickness and the occurrence of part defects of PA6 parts produced with water assisted injection moulding. The study examined two polyamides (PA F223D, PA F130E1) and polypropylene 400 GA05 that was used as a reference material. According to a design of experiments, the water volume flow rate, the water injection delay time and the melt temperature are the investigated processing parameters. The water volume flow rate settings are 10, 20 and 30 l/min, the injection delay time settings are 1,5s, 5s and 8,5s and the melt temperature settings are 240 °C, 260 °C and 280 °C. It was found that the residual wall thickness showed a large distribution for all three materials, even for shots from a single experiment and therefore an extra analysis was made on the weight of the products. The product weight can give an indication for the wall thickness as a low weight usually corresponds to small thicknesses. Based on this theory it was found that the water volume flow rate has little influence on the weight and wall thickness. A larger delay time increases the viscosity of the polymer and leads to higher weight and a larger wall thickness. The melt temperature has the opposite effect, decreasing the viscosity at higher temperatures and therefore decreasing the wall thickness and weight. PP has a lower weight comparing with the two polyamides. This can be explained that PP has a higher molecular weight and molecular weight distribution. A higher molecular weight gives a parabolic velocity profile and a higher molecular weight distribution shows a square blocked velocity profile causing a higher velocity located on the wall. The higher velocity causes a higher shearing giving a lower viscosity. This results in more removal of the polymer and the residual wall thickness decreases. In fact, a lower residual wall thickness exhibits a lower weight of product. The water inclusions for the three materials tend to decline when the water flow rate increases although PP shows some irregularities. The delay time has an overall optimum profile. Intermediate settings exhibit less inclusions in comparison to other settings. The melt temperature has the opposite effect of the delay time so more water inclusions occur when higher temperatures are applied. Other defects like fingering and double wall are also influenced by the investigated processing parameters. The water flow rate shows an optimum profile for double wall, so an intermediate setting will yield the best results. For fingering the three materials all act in a different way to the flow rate. An optimum profile also occurs for double wall when the delay time is investigated. In general, fingering increases when the delay time increases, but the materials show a lot of irregularities. An increase in melt temperature causes an overall increase of fingering and double wall. Comparing PA6 and PP, PP shows an overall smaller residual wall thickness than PA6, but on average the same percentage of part defects. This means that a reduction in residual wall thickness does not influence the product quality for part defects positively. When comparing the different polyamides 6, the investigated low viscosity polyamide 6 PA F223-D show less water inclusions and fingering but more double wall than the medium viscosity polyamide 6 PA F130-D. The best choice for a polyamide depends on the relative importance of the negative influence of each part defect on the product quality. This is discussed in detail in the next paragraph. To get an indication of the quality of the product IR images can be used. It was found that a uniform heat distribution corresponds to few defects and irregularities point to the presence of defects like fingering or double wall. The internal texture of the surface can not be examined with IR. This study concludes that the investigated parameters have a significant influence on the presence of part defects and on the residual wall thickness. However, there are still irregularities in the results of the fingering phenomenon that can not be explained yet with the current knowledge of the water assisted injection moulding process. Therefore further analysis will be necessary to examine this part defect. Further research can be done by expanding the design of experiments and by producing more shots for each experiment. Producing more than three shots of each experiment should give more corresponding results, because the standard deviation of three shots is usually high. 4. 2 Selection of the material for WAIM Three materials were used in this experiment namely PA F223D, PA F130E1 and PP as reference. The residual wall thickness, weight of product, water inclusions and part defects like fingering and double wall must be compared with each other to choose the best material. This by varying the selected parameters like water volume rate, water injection delay time and melt temperature. PP has in general the lowest weight of product and residual wall thickness for the three investigated parameters: water volume rate, water injection delay time and melt temperature. As a result of a smaller residual wall thickness, PP has the lowest weight of product. Considering the water inclusions a decreasing tendency is obtained when a higher water volume flow rate and water injection delay time is used. There is a trend toward higher water inclusions when higher melt temperature are applied. Regarding to fingering and double wall, an opposite effect is noticeable. Increasing the water volume rate and water injection delay time gives a decreasing fingering tendency but more double wall effects. For a higher melt temperature, an increase of fingering and double wall is observed. PA F130E1 and PA F223D are quiet similar to each other in weight of product and residual wall thickness. For the weight of product PA F130E1 and PA F223D correspond to each other and for the residual wall thickness they do not differ much for all three investigated parameters. Regarding the water inclusions, both polyamides decline when water the flow rate increases. The highest flow rate provides more shearing and therefore a lower viscosity resulting in more water inclusions. Increasing the water injection delay time leads to lower water inclusions because the viscosity increases which makes it more difficult for water to penetrate into the walls. When higher melt temperatures are applied, results in a trend towards higher water inclusions because of the lower viscosity. In general, PA F223D shows more water inclusions comparing with PA F130E1 for the water volume flow rate, water injection delay time and the melt temperature. Considering fingering and double wall, different results were observed for the two polyamides. In general it is remarkable that PA F223D shows more fingering then PA F130E1 while PA F130E1 gives more double wall then PA F223D and this for the three investigated parameters. For the water volume flow rate, the polyamides act in different ways towards fingering. Although, for double wall the flow rate shows an optimum for the polyamides so an intermediate setting gives the best results. When the water injection delay time increases there is also an increasing tendency of fingering observed but the materials show a lot of irregularities. Increasing the melt temperature gives an increase of fingering and double wall as well. In this investigation can be concluded that both polyamides have their advantages and disadvantages. A selection of the best polyamide depends on which effect is undesirable. The residual wall thickness are the same for the two polyamides. PA F223D shows more water inclusions and fingering for all investigated parameters. However, PA F223D shows less double wall and therefore the best results. PA F130E1 in contrary gives more double wall effects but less fingering and water inclusions. In fact, PA F223D is preferred when double wall must be reduced and PA F130E1 is preferred when fingering and water inclusions must be reduced. Further investigation is necessary on another type of polyamide which improves the product quality using WAIM. 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