Thermomechanical Analysis (TMA) Instrumentation

Thermomechanical Analysis (TMA) Instrumentation THERMOMECHANICAL ANALYSIS (TMA) Aisyah Radhiah Binti Ahmad INSTRUMENTATION OF TMA 1.1 The Instrumentation Figure 1: The simple schematic diagram of TMA [1]. The sample tube that is located in the center of the furnace is used to control the temperature and atmosphere. The sample temperature is measured with a thermocouple that is located near the sample. The area around the sample can usually be both heated and cooled to prevent the heat-rise problem and the sample temperature (sensed by a thermocouple) has to be directed to programmer control. The sample platform and the probe are made from a material such as quartz. Quartz is chosen as it has a low, reproducible, accurately known coefficient of thermal expansion and also it has low thermal conductivity to isolate the LVDT from the temperature changes in the furnace. The probes can also be made from alumina and metals depending on the temperature range and the measurement purpose [2]. The heavy black probe measures the position of the sample surface with a linearly variable differential transformer, LVDT. The floating suspension act as a balance for the arm arrangement, combined with added weights at the top, allowing the probe weight to be counterbalanced that can be used to control the force on the sample [3]. A purge gas is used during the TMA measurements. Its purpose is to ensure continuous laminar gas flow to prevent the formation of air turbulence as the temperature is being increased and to prevent deposition of degradation products inside the various parts of the instrument. The purge gas is also used to increase heat transfer to the sample and to prevent oxidation in high temperature measurements. Helium is chosen for this purpose because of it has a high thermal conductivity [4]. Figure 2: The TMA Instrument [5]. 1.2 Operating the TMA The instrument is warmed up before putting the sample. The sample is prepared by according to the modes used. For example, the sample should be flat for compression modes to make sure the sample is in a good contact with the probe. The sample is put into the furnace and the probe touched the sample. The probe is integrated into an inductive position sensor. For temperature measurement of the sample, the thermocouple is placed near the sample. The system is heated at a slow rate. If the specimen expands or contracts, the probe will be moved. By applying the force on the sample from the Force Generator by the probe, the sample temperature is changed in the furnace. The sample deformation such as Thermal Expansion and Softening with changing temperature is measured as the probe displacement by the Length Detector. Linear Variable Differential Transformer (LVDT) is used for Length Detection sensor. The measurement consists then of a record of force and length versus temperature [6]. 1.3 Calibration of the instrument The calibration of the instrument needs to be done before using the TMA. A standard calibration is needed and should be done at the same heating rate as is used in the sample experiment. The calibration sample that is used should be in the thickness range span of the sample. The TMA instrument must be calibrated in height force, eigen-deformation, temperature, and expansion. The calibration of the instrument need to be done to reduce the different between measures values of the parameters with their true values [4]. 1.4 Modes of operation The measurement can be carried out in various modes of sample configuration. Figure 3: TMA probe types (left-right): compression, penetration, tension, volumetric [7]. Compression probe is used for applying low load for a wide area of sample for thermal expansion measurements (thermodilatometry). For the penetration probe, it is used for the sample that applies a high load under a small area of sample for the purpose of measuring softening temperatures. This technique can measure the transitions of a material as thin as 10 microns. Tension probe used for the measurement of the thermal expansion and the thermal shrinkage of the sample for measuring non-self supporting specimens. It is used for the samples like thin films and fibres under tension [7]. Volumetric probe used for measuring the thermal volumetric expansion of irregularly shaped sample surrounded by an inert packing material (alumina powder or silicone oil). The glass dilatometers are used in this technique where the change in the level of a liquid is observed. By dipping the sample in the silicone oil or alumina powder, the expansion of the sample is recorded as a vertical movement by the TMA. The probe for this technique usually has a small surface area to cover the sample [8]. Figure 4: volumetric probe [8]. References Menard, K. P. (2008). Dynamic mechanical analysis: a practical introduction. CRC press. Menczel, J. D., Prime, R. B. (2009). Thermal analysis of polymers, fundamentals and applications. John Wiley Sons. Brown, M. E., Gallagher, P. K. (1998). Handbook of thermal analysis and calorimetry: Principles and Practice (Vol. 1). Elsevier. Wunderlich, B. (2005). Basics of thermal analysis. Thermal Analysis of Polymeric Materials. 1.Introduction to Thermomechanical Analysis. Available from: http://www.anasys.co.uk/library/tma1.htm. 2.Brown, M.E. and P.K. Gallagher, Handbook of thermal analysis and calorimetry: Principles and Practice. Vol. 1. 1998: Elsevier. 3.Wunderlich, B., Basics of thermal analysis. Thermal Analysis of Polymeric Materials, 2005. 4.Menczel, J.D. and R.B. Prime, Thermal analysis of polymers, fundamentals and applications. 2009: John Wiley Sons. 5.TMA analyzer / thermomechanical. Available from: http://www.directindustry.com/prod/linseis-thermal-analysis/tma-analyzers-thermomechanical-30771-406852.html. 6.Description of TMA. Available from: http://www.hitachi-hitec-science.com/en/products/thermal/tec_descriptions/tma.html. 7.Haines, P.J., Principles of thermal analysis and calorimetry. Vol. 30. 2002: Royal society of chemistry. 8.Menard, K.P., Dynamic mechanical analysis: a practical introduction. 2008: CRC press. References Introduction to Thermomechanical Analysis. from http://www.anasys.co.uk/library/tma1.htm Brown, Michael E, Gallagher, Patrick K. (1998). Handbook of thermal analysis and calorimetry: Principles and Practice (Vol. 1): Elsevier. Wunderlich, Bernhard. (2005). Basics of thermal analysis. Thermal Analysis of Polymeric Materials. Menczel, Joseph D, Prime, R Bruce. (2009). Thermal analysis of polymers, fundamentals and applications: John Wiley Sons. TMA analyzer / thermomechanical. from http://www.directindustry.com/prod/linseis-thermal-analysis/tma-analyzers-thermomechanical-30771-406852.html Description of TMA. from http://www.hitachi-hitec-science.com/en/products/thermal/tec_descriptions/tma.html Haines, Peter J. (2002). Principles of thermal analysis and calorimetry (Vol. 30): Royal society of chemistry. Menard, Kevin P. (2008). Dynamic mechanical analysis: a practical introduction: CRC press.

Liberalism and Mercantilism Essay

International political economy is an important subdiscipline of international relation. It has three main ideologies, Liberalism, Mercantilism and Marxism. In this essay there will be three parts, first part is to demonstrate what the Liberalism and Mercantilism are on the perspective of international political economy and then the second part is to compare and contrast these two ideologies of political economy. At last, give a conclusion to the Liberalism and Mercantilism. Liberalism The liberal perspective on political economy is embodied in the discipline of the Western economics (Gilpin, 1987). It emphasizes the individual interests, the freedom and the maximization of economic benefit. Economic liberalism is based on the theory of â€Å"invisible hand† of Adam Smith and founded by David Ricardo in the seventeenth century. In the 1940s, Friedrich August von Hayek made a renaissance and a new explanation to it. Moreover, Milton Friedman made great contribution to the economic Liberalism in the 1970s. The basic standpoints of economic Liberalism are that people should be treated as the â€Å"rational economic animal† and market emerges spontaneously to satisfy human need. When the market running it develops according to its internal logical rule, rather than people’s will. Even through economic activity can enhance national power, the core of it is to bring beneficial to each consumer. Due to each person are both consumer and producer, so ev ery action of each person should be a rational choice in the market. Because resources are scarce, every decision involves an opportunity cost, a tradeoff among alternative uses of available resource (Samuelson, 1980, p.27). Get something at the cost of giving up something else. Hence everyone’s rational choices contribute to a balance among various powers in the market. The balance of these various powers makes the market have its intrinsic stability. That means the market is not only an automatic operation system, but also an autocorrection equilibrium system. Any intervention, especially from the government, is helpless to market development and destroys the intrinsic stability of market. Therefore, economic Liberalism opposes any form of government intervention strongly. Economic liberals claim that politics makes people separation while economy  makes people solidarity. A liberal international economy will have a moderation influence on international politics as it creates bonds of mutual interests and a commitment to the status quo. (Gilpin, 1987) Mercantilism According to Viner (1994), Mercantilism is a theory that state uses its economic interests widespreadly to regulate its economic activities. It emphasizes economic activities should serve for the interests of state and goal of state building (Gilpin, 1975). There are three theoretical points of Mercantilism (Magnusson, 1993). Firstly, Mercantilism pays attention to the currency and development of commerce. It regards the amount of currency (mainly gold and silver) as an important symbol to measure the degree of state’s affluence. Secondly, Mercantilism pays attention to foreign trade and seeks for trade surplus. It has no faith in market mechanism for state building. Thirdly, Mercantilism pays attention to the development of domestic industry, at the same time cultivates and protects the infant industry. According to Sen (1984), Mercantilism believes that industry has spillover effects and it associates the possession of industry with economic self-sufficiency and political autonomy. The most important, industry is prized because it is basic of military power and central to national security in the modern world. Actually, Mercantilism can be divided into two parts, â€Å"benign† Mercantilism and â€Å"malevolent† Mercantilism. The â€Å"benign† Mercantilism considers the safeguarding of national economic interests as the minimum essential to the security and survival of the state. It hopes to develop and protect domestic industry with the state power (like tariff, exchange rate, etc) and to prevent foreign product competition, for example, monetary policy. While â€Å"malevolent† Mercantilism advocates to build a powerful state and to ensure foreign trade unblocked with using of state power and regards the international economy as an arena for imperialist expansion (Hirschman, 1969). Even through there are differences between these two Mercantilisms, the goal of Mercantilism that makes state rich and powerful is clear and unified. (Magnusson, 1987) Compare and contrast of Liberalism and Mercantilism. The debate between Liberalism and Mercantilism has a long history. There are  three main differences between these two ideologies of political economy according to Goddard (2003). Firstly, Liberalism focuses on the market mechanism and believes that the economic role of government is limited. However, Mercantilism pays attention to the role of state and considers politics decide the economic activity. Secondly, Mercantilism regards world economy as a zero-sum game which means one country’s loss is as the prerequisite to another country’s gain. Moreover, Mercantilism thinks conflict between different countries is inevitable. Each country can only rely on its own resources to protect itself eventually. However, Liberalism opposes the zero-sum game. It believes the only consequence of the zero-sum game is war. Liberalism stresses the mutual benefit and a win-win situation which lead to international cooperation and interedependency. That is, dividing an existing cake is inferior to make a bigger cake (By promoting economy growth). Finally, Mercantilism focuses on the importance of military power and regards political and economic power as a way to ensure the security of state. Liberalism thinks accumulation of military power and other powers reduces the economic efficiency. Peace is more effective than war. The following table coming from Frederic shows the specific difference between Liberalism and Mercantilism (1999). Conclusion Even through the most of viewpoints of Liberalism and Mercantilism are different, these two ideologies of political economy have the value of existence respectively and are worth to research. In addition, Liberalism and Mercantilism have their own advantage and disadvantage. When begin to research them, people should have a critique view to accept their viewpoints. In summary, Liberalism and Mercantilism are two important ideologies of political economy Reference 1. Frederic S. Pearson and Simon Payaslian. International Political Economy: Conflict and Cooperation in the Global System. The Mcgraw-Hill Companies, 1999, P.33 2. Gilpin, Robert. 1975 U.S Power and the Multionational Corporation: The Political Economy of Foreign Direct Investment. New York: Basic Books 3. Gilpin, Robert 1987. The Political Economy of International Relations. Oxford: Princeton University Press. Chapters 2 P.33-P.79 4. Goddard, C. Roe; Cronin, Patrick and Dash, Kishore C. (eds.) (2003). International Political Economy: State-Market Relations in a Changing Global Order. Boulder, CO: Lynne Rienner Publishers (chapters 2-4, 6, 11-13). 5. Hirschman Albert.O 1969 â€Å"Effects of Industrialization on the Market of Industrial Countries† In bert F. Hoselitz, cd. The Progress of Underdeveloped Areas. Chicago: University of Chicago press. pp. 83-270. 6. Magnusson Lars. 1987. â€Å"Mercantilism and Reform-mercantilism: The Rise of Economic Discourse in Sweden During the Eighteenth Century† History of Political Economy 19: 3. 7. Magnusson Lars. 1993. Mercantilism. The Shaping of Economic Language. London: Routledge 8. Samuelson Paul A. 1980. Economics. With the Assistance in Statistical Updating of William Samuelson. New York: Mcgraw-Hill. 9. Sen, Gautam. 1984 The Military Origins of Industrialization and International Trade Rivalry. New York: St. Martin’s Press 10. Viner, Jacob. 1994. Power versus plenty as objectives of foreign policy in the seventeenth and eighteenth centuries, World Politics, No.1 p.11

Farm Management - Free Essay Example

Sample details Pages: 7 Words: 2057 Downloads: 5 Date added: 2017/06/26 Category Management Essay Type Critical essay Level High school Did you like this example? Farm Management Assess the current capacity of ‘Holly Farm and critically evaluate the optional ways of achieving the intended growth in the number of visitors, bearing in mind that capital investment is not available, although self-financing revenue earning ventures can be considered. 1. Introduction This piece examines the case of Holly Farm, and the plan proposed by Gillian Giles to attempt to boost the number of visitors attending the farm. Holly Farm is currently quite a successful example of a farm that has diversified into visitor activities to boost its overall revenue levels. Don’t waste time! Our writers will create an original "Farm Management" essay for you Create order However, the farm has now reached a point at which visitor levels are relatively steady, and hence the farm is failing to grow its revenue significantly. This piece will thus investigate the current situation at the farm, including the current visitor numbers and the projected capacity for the farm. This data will then be used to determine the extent to which the farm can try to attract more visitors and the strategies that could be used to achieve this. This analysis will take place assuming that the farm is unable to raise further capital investment, other than through additional services that will also generate revenue. 2. Analysis and current situation Car park capacity Coach spaces 6 Car spaces 40 Average visitors per coach 35 Average visitors per car 3 Daily coach visitor capacity 210 Daily car visitor capacity 120 Total daily capacity 330 Current visitor numbers April May June July August September October Total Visitors 1,200 1800 2800 3200 3400 1800 600 14,800 Days open 16 16 16 16 16 16 16 112 Weekend days open 8 8 8 8 8 8 8 56 Week days open 8 8 8 8 8 8 8 56 Average weekend day visitors 100 150 233 267 283 150 50 176 Average weekday day visitors 50 75 117 133 142 75 25 88 Daily car park capacity 330 330 330 330 330 330 330 330 Weekend utilisation 30.3% 45.5% 70.7% 80.8% 85.9% 45.5% 15.2% 53.4% Weekday utilisation 15.2% 22.7% 35.4% 40.4% 42.9% 22.7% 7.6% 26.7% Daily milking parlour capacity 200 200 200 200 200 200 200 200 Weekend milking parlour visitors 80 120 187 213 227 120 40 141 Weekday milking parlour visitors 40 60 93 107 113 60 20 70 Weekend utilisation 40.0% 60.0% 93.3% 106.7% 113.3% 60.0% 20.0% 70.5% Weekday utilisation 20.0% 30.0% 46.7% 53.3% 56.7% 30.0% 10.0% 35.2% The analysis of the current situation is based on the following assumptions: On average, each coach visiting the farm will contain 35 visitors, and each car will contain 3 visitors. This is to account for the number of single parent families and families with only one child that may visit the farm. The proportion of visitors by coach and by car are roughly proportional to the respective visitor capacity for coach and car visitors The car and coach spaces cannot be used flexibly, i.e. coaches cannot park in the car spaces and vice versa The milking sheds can support 80 people per hour for a period of two and a half hours, thus they have a daily capacity of 200 The visitors are spread roughly evenly throughout each month 90% of visitors arrive after 12:30pm, and the visitors that arrived before 12:30pm at still there at this time. As such, around 1pm all visitors to the farm are at the farm and hence all need a car park space The analysis indicates that the farm is currently very close to its maximum visitor capacity in July and August, with 80.8% and 85.9% capacity utilisation in the car park on these days. With 80% of visitors going to the milking parlour, the parlour itself is already over capacity on these days, with capacity utilisation levels of 106.7% and 113.3% respectively. It must be assumed therefore that some visitors that would have liked to have visited the milking sheds were unable to do so due to the capacity constraints. 3. Different scenarios Two primary scenarios have been considered. The first is where the farm engages in widespread promotional activity designed to boost overall levels of attendance by 50%. The second is where the farm engages in targeted promotional activity designed to encourage school visits during the week, thus boosting weekday attendance levels by 50%. The analysis for these two scenarios is shown below: 3.1 Boost visitor demand by 50% on all days Projected visitor numbers April May June July August September October Total Visitors 1,800 2,700 4,200 4,800 5,100 2,700 900 22,200 Days open 16 16 16 16 16 16 16 112 Weekend days open 8 8 8 8 8 8 8 56 Week days open 8 8 8 8 8 8 8 56 Average weekend day visitors 150 225 350 400 425 225 75 264 Average weekday day visitors 75 113 175 200 213 113 38 132 Daily car park capacity 330 330 330 330 330 330 330 330 Weekend utilisation 45.5% 68.2% 106.1% 121.2% 128.8% 68.2% 22.7% 80.1% Weekday utilisation 22.7% 34.1% 53.0% 60.6% 64.4% 34.1% 11.4% 40.0% Actual average weekend day visitors 150 225 330 330 330 225 75 238 Actual average weekday day visitors 75 113 175 200 213 113 38 132 Total weekend day visitors 1200 1800 2640 2640 2640 1800 600 13320 Total weekday day visitors 600 900 1400 1600 1700 900 300 7400 Total visitors 1800 2700 4040 4240 4340 2700 900 20720 Daily milking parlour capacity 200 200 200 200 200 200 200 200 Weekend milking parlour visitors 120 180 264 264 264 180 60 190 Weekday milking parlour visitors 60 90 140 160 170 90 30 106 Weekend utilisation 60.0% 90.0% 132.0% 132.0% 132.0% 90.0% 30.0% 95.1% Weekday utilisation 30.0% 45.0% 70.0% 80.0% 85.0% 45.0% 15.0% 52.9% It should be noted that, for this scenario, as the capacity of the car park is limited to around 330 people per day, some visitors who wish to visit the farm on weekends in July and August will be unable to do so. The farm will thus have maximum average daily weekend visitor numbers during these months of 330. A plan should thus be put in place to manage capacity on these days, and ensure that visitors do not travel a long way only to find there is no space in the car park. 3.2 Boost visitor demand by 50% for weekdays only Projected visitor numbers April May June July August September October Total Average weekend day visitors 100 150 233 267 283 150 50 264 Average weekend day visitors 75 112.5 175 200 212.5 112.5 37.5 132 Weekend days open 8 8 8 8 8 8 8 56 Week days open 8 8 8 8 8 8 8 56 Total weekend day visitors 800 1200 1867 2133 2267 1200 400 9867 Total weekday day visitors 600 900 1400 1600 1700 900 300 7400 Total visitors 1400 2100 3267 3733 3967 2100 700 17267 Daily milking parlour capacity 200 200 200 200 200 200 200 200 Weekend milking parlour visitors 80 120 187 213 227 120 40 211 Weekday milking parlour visitors 60 90 140 160 170 90 30 106 Weekend utilisation 40.0% 60.0% 93.3% 106.7% 113.3% 60.0% 20.0% 105.7% Weekday utilisation 30.0% 45.0% 70.0% 80.0% 85.0% 45.0% 15.0% 52.9% In this scenario, the capacity of the car park does not represent a critical factor, as the farm will never attract more than 330 visitors per day on average. This will thus help relieve the problems associated with an across the board increase in visitor numbers. 4. Suggestions and validation The results from the first scenario show two main issues with Gillians desire to boost visitor numbers. The first is that boosting levels of demand will cause capacity issues in the car park in the busy months of June, July and August. This will create issues for the farm as it may result in visitors arriving and having to be turned away, which could create a negative image for the farm. In addition to this, boosting the number of visitors during these peak periods will result in the milking sheds becoming very congested with long queues, and potentially large numbers of people unable to visit the sheds. As the carousel appears to be a very important attraction, if people are unable to visit it they may again become unhappy and this could damage the reputation of the farm as well as causing problems for the employees running the attraction (Waters, 1999, p. 85). In terms of the actual impact on visitor numbers, the 50% increase in demand across the board would be expected to boo st visitor numbers by around 40%, from 14,800 to 20,720 per annum. In contrast, the 50% increase during weekdays would boost visitor numbers by around 17%, from 14,800 to 17,267 per annum. As such, the 50% increase across the board would be more beneficial in terms of total numbers, but would also likely cost more to implement, and would not provide a full 50% increase in visitor numbers. In order to achieve this 50% increase, the best option would be to implement both the general marketing scheme to increase overall numbers, and the targeted partnership scheme with schools to boost visitor numbers during the weekdays. This would help achieve the 50% target within the existing capacity constraints. At the same time, the farm will need to carry out targeted analysis of the current levels of car park usage, in order to determine whether it should target more coach groups or more family groups depending on the capacity utilisation of the coach and the car spaces. However, the best way to achieve the goal of a 50% expansion in visitor numbers whilst avoiding the potential issues with capacity and overcrowding the in the milk sheds as discussed above would be to address the constraints the company faces. According to Huefner (2011, p. 40), â€Å"companies of all sizes are limited by any number of constraints: capacity of their plants and other physical structures, distribution channels, rules and regulations, size and education of the workforce, and access to raw materials, to name a few†. As such, addressing and overcoming these constraints is a vital aspect of operations management, and enables companies to improve their profitability without having to invest additional capital. One of the main ways this could be achieved for the farm would be to improve capacity management through car park flexibility. Specifically, the farm should look to arrange the spaces in the car park so that coaches can park across two or three car parking spaces in order to bo ost capacity. This is because two or three cars will bring an average of around nine visitors, but a coach can contain 35 visitors. As such, by allowing some car spaces to be used for coaches, the farm could focus on attracting more coach groups at the weekends, and thus boost the effective capacity of the car park. This will play a vital role in boosting overall capacity, as parking is a critical factor in determining travel destinations (Nurul Habib et al, 2012, p. 154). This would also help the farm profit more by offering discounted entry fees to coach tours, as well as potentially running coaches from larger nearby car parks where other visitors could park and then ride to the farm. Another important tool that could be used to boost revenues and visitor numbers is to engage in superior demand management, through pricing structures. According to Hwang et al (2010, p. 465) the use of pricing for demand management plays a key role in the effective management of demand levels, a nd thus maximises potential revenue levels. In this case, the farm could offer half day visitor structures, whereby people who arrive later, after 4pm, when around 20% of visitors have left, will be offered discounted prices. There could also be discounted prices offered to people who arrive at 11am and stay only for a couple of hours, thus leaving before the large groups arrive. This would help ensure that more visitors can attend during quieter periods. Similarly, setting higher prices at the weekend and lower prices during the week could help ensure that more people came on Friday and Monday, when the farm is quiet, instead of at the weekends when it is busy. These efforts could be combined with revenue management techniques which use differential pricing strategies and capacity allocation tactics to maximise overall revenue levels for the farm, as well as visitor numbers (Deng et al, 2008, p. 737). In addition to this, the farm could boost capacity by opening new attraction n earby such as a go kart course. This would create funds to expand the car park and encourage people to visit both attractions at once. Different tickets could be sold for people who want to go on the go kart in the morning and visit the farm in the afternoon and vice versa, in order to smooth out demand levels across the two attractions. These efforts would improve capacity utilisation in the car park and boost the overall visitor numbers, but efforts will still be needed to address the issue of queuing for the milking shed, and ensuring capacity is smoothed in this area. One of the main ways to achieve this would be for each visitor to the milking shed to come to the shed when they first arrive and book a time slot for their viewing. This would help customers avoid having to queue and reduce customer discontent due to the length of the queue (Xu et al, 2007, p. 971). It would also ensure that customers were not left waiting until the end of the day and then frustrated that the m ilking shed was not open for them to see the milking. This approach would thus help reduce the queues in the milking shed and hence support the increase in visitor numbers for the farm as a whole. References and Bibliography Deng, H. Wang, Q. Leong, G. and Sun, S. (2008) The Usage of Opportunity Cost to Maximize Performance in Revenue Management. Decision Sciences; Nov2008, Vol. 39 Issue 4, p737-758 Huefner, R. (2011) A Guide to Integrating Revenue Management and Capacity Analysis. Management Accounting Quarterly; Autumn2011, Vol. 13 Issue 1, p40-46 Hwang, J. Gao, L. and Jang, W. (2010) Joint demand and capacity management in a restaurant system. European Journal of Operational Research; Nov2010, Vol. 207 Issue 1, p465-472 Nurul Habib, K. Morency, C. and Trà ©panier, M. (2012) Integrating parking behaviour in activity-based travel demand modelling: Investigation of the relationship between parking type choice and activity scheduling process. Transportation Research Part A: Policy Practice; Jan2012, Vol. 46 Issue 1, p154-166 Shim, J. and Siegel, J. (1999) Operations Management. Barrons Educational Series. Waters, D. (1999) Operations Management. Kogan Page Publishers. Xu, S. Long, G. and Jihong, O. (2007) Service Performance Analysis and Improvement for a Ticket Queue with Balking Customers. Management Science; Jun2007, Vol. 53 Issue 6, p971-990

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