Free Essays on T.S. Eliots “The Wasteland“ And Sept 11th

The events of September 11 have forever changed America and on a smaller scale, the way in which I view T.S. Eliot’s poem, â€Å"The Wasteland.† Suddenly, a seemingly dark and distant poem about death and destruction evokes images of everyday men and women leaping from buildings and running for their lives, and creates an unsettling feeling that it could have been us. The first section of â€Å"The Wasteland,† The Burial of the Dead connected to my feelings and thoughts of current events the most. Death, the most final result of all evils is expressed with little subtlety or compassion. The tone is sorrowful and helpless, just as many felt when the terrorists attacked. If it snowed in New York today, we may feel an unconscious relief of our worries, just as Eliot suggested. â€Å"Winter kept us warm, covering earth in forgetful snow,† (Line 5-6) as the snow blanketed the rubble and physical destruction, sheltering our eyes from the horrific images. We are chilled by fear now, and are reminded of our possible fate every time we see the remains of the World Trade Center. The paradoxical image of winter keeping us warm is actually not that implausible, as our hearts find time to heal from the tragedies that occurred. America’s struggle to relax, watch a movie, or listen to music are supported by Eliot’s form of relaxation, â€Å"we stopped†¦ and went on in the sunlight†¦ and drank coffee, and talked for an hour.† (Lines 9-11) His tone about those activities seems calm, and peaceful, and it can most likely be assumed that the conversation was enjoyable, why else would one talk to someone for an hour? Eliot reflects about more innocent and carefree days, â€Å"My cousin’s, he took me out on a sled, and I was frightened. He said, Marie, Marie, hold on tight. And down we went.† (Lines 14-16) The narrator seems to long for a time like this, just as I long for innocence and untroubled days. He imagines a time when his biggest fear was... Free Essays on T.S. Eliot's â€Å"The Wastelandâ€Å" And Sept 11th Free Essays on T.S. Eliot's â€Å"The Wastelandâ€Å" And Sept 11th The events of September 11 have forever changed America and on a smaller scale, the way in which I view T.S. Eliot’s poem, â€Å"The Wasteland.† Suddenly, a seemingly dark and distant poem about death and destruction evokes images of everyday men and women leaping from buildings and running for their lives, and creates an unsettling feeling that it could have been us. The first section of â€Å"The Wasteland,† The Burial of the Dead connected to my feelings and thoughts of current events the most. Death, the most final result of all evils is expressed with little subtlety or compassion. The tone is sorrowful and helpless, just as many felt when the terrorists attacked. If it snowed in New York today, we may feel an unconscious relief of our worries, just as Eliot suggested. â€Å"Winter kept us warm, covering earth in forgetful snow,† (Line 5-6) as the snow blanketed the rubble and physical destruction, sheltering our eyes from the horrific images. We are chilled by fear now, and are reminded of our possible fate every time we see the remains of the World Trade Center. The paradoxical image of winter keeping us warm is actually not that implausible, as our hearts find time to heal from the tragedies that occurred. America’s struggle to relax, watch a movie, or listen to music are supported by Eliot’s form of relaxation, â€Å"we stopped†¦ and went on in the sunlight†¦ and drank coffee, and talked for an hour.† (Lines 9-11) His tone about those activities seems calm, and peaceful, and it can most likely be assumed that the conversation was enjoyable, why else would one talk to someone for an hour? Eliot reflects about more innocent and carefree days, â€Å"My cousin’s, he took me out on a sled, and I was frightened. He said, Marie, Marie, hold on tight. And down we went.† (Lines 14-16) The narrator seems to long for a time like this, just as I long for innocence and untroubled days. He imagines a time when his biggest fear was...

7 Surprising Facts About Homeschooling

7 Surprising Facts About Homeschooling If youre new to the idea of homeschooling, you may think its just like traditional school, but without the classroom.  In some  ways, youd be right -  but there are many important differences. And those differences make homeschooling the best choice for many families.   Whether youre a new  homeschooler  or are just curious about how it works, here are seven facts about homeschooling that may surprise you. 1. Homeschoolers Dont Have to Do the Same Work as Kids in School In some states, public school students have the option to  do their work at home online. Because theyre still enrolled in the public school system, those students follow the same curriculum as kids in school. But in general, homeschoolers also have the option to create their own curriculum -  or not use a curriculum at all. Often they choose lots of hands-on activities and ​learning resources other than textbooks. So instead of trying to keep up with what students in their grade are doing, homeschooling students can study Ancient Greece while their peers study the Civil War. They can  explore states of matter with dry ice  or go  in-depth on evolution  while kids their age are memorizing the parts of a flower. The freedom to follow childrens interests is one of the aspects of homeschooling many families like best. 2. Homeschooling Parents Stay up to Date on How Children Learn and Grow To keep their teaching license current, classroom teachers may be required to attend professional development workshops. At these workshops, they study the latest information and strategies about how children learn. But research on education topics like learning styles, brain development, and the links between physical activity and memory can be found in books, magazines and websites available to the public as well. Thats why even homeschooling parents who dont have teaching degrees are familiar with the latest information on how to be a better teacher. Whats more, experienced homeschoolers -  including those with a professional background in education or child development - are very willing to offer support to other homeschoolers, whether online or at  parent meetings. So the knowledge base within the homeschool community is vast and easily accessible. 3. Its Not Unusual for Classroom Teachers to Homeschool Their Own Children Nobody knows how schools really operate better than classroom teachers. So its not surprising that  many licensed, trained, experienced public school educators decide to homeschool their  kids. As they will tell you, homeschooling lets them use their skills and experience without a lot of  red tape. At home, dedicated professional teachers can create the kind of  learning environment every child should have. 4. Were Still Waiting for a Good Study of Homeschooling You may have  read articles that claim homeschoolers do better than average on standardized tests, come from wealthier families, and homeschool mainly because of religious beliefs. None of the conventional wisdom about homeschooling is backed by rigorous scientific research, however. Most of the statistics you read were collected by groups with a vested interest in proving  that either homeschooling is a cure-all for American education or the end of civilization as we know it. The true answer is more complicated and yet to be reliably studied. 5. Lots of Homeschooling Parents Are Also Working Parents Along with the idea that homeschooling families are wealthier than average is the notion that teaching your own children means one parent must be home full time  and not working. This is not true. Homeschoolers come up with many creative ways to balance work and homeschooling. 6. Homeschoolers Dont Need a High School Diploma to Get into College Colleges have come to recognize that homeschool students are as well prepared as traditionally-schooled students for college life. Thats why they often have a special application process for  college-bound homeschoolers  that takes into account their varied backgrounds. Some homeschoolers also get around requirements for standardized tests like the SAT by taking enough community college classes while in high school to apply as transfer students. 7. Homeschoolers Can Get Many of the Same Educator Discounts as Classroom Teachers Classroom teachers know that national chains and local stores that carry school supplies, art materials, books, and teaching aids often offer educator discounts. In many cases, homeschooling parents can get these discounts too. Stores that have offered discounts include Barnes Noble and Staples. Special educator discounts extend to field trips as well. Museums, summer camps, amusement parks and other educational and recreation venues have learned that offering special events and programs for homeschoolers can boost business during slow periods. For instance, Old Sturbridge Village in Massachusetts, the Colonial-era living museum, has run popular Home School Days for several years. Some national companies also include homeschoolers in competitions and incentive programs aimed at school kids. For example, homeschoolers can earn rewards for reading from the Six Flags chain of amusement parks and Pizza Hut restaurants. Policies change, so its always a good idea to ask. You may also want to be prepared to show proof that you homeschool, such as  a letter from the school district or your  homeschool group membership card.

Enhancing Occupational Health and Safety Term Paper - 1

Enhancing Occupational Health and Safety - Term Paper Example Occupational hazard and occupational diseases are the inevitable; they will be there in the present environment of work environment where corrosive chemicals, heat and many other factors are involved. The manufacturing unit is the worst hit where many people are losing their lives due to many accidents. However, it is very much important to reform the health related programs in the recent organizations as the expectations of the employees are changing with the changing working time and working environment. The financial relives are not the only effective factor for the satisfying job, in the recent time the leave structure, flexibility of work time, the health insurance packages and internal medical supports have become the great issues. The new generation of employees has new expectations from the employees and practically it is the responsibility of the employers to take care of the health of the fellow employees as far as they are working in the same company. This particular paper will focus on the recent scenario of the occupational hazards and with respect to that the safety measures will be discussed intensely. The concept of occupational health safety was evolved in the Europe in the early nineteenth century. The rapid reformation of the occupational health reformation was seen in the Europe and eventually the new trends of the safety measures were shifted to America from the Europe (Taylor, Easter & Hegney 2). The changing in the legislation has helped many poor women and children to stay out of the occupational accidents and occupational hazards. However, the occupational disasters and accidents have a great impact over the local publics too. The laws related to the occupational hazards and standard of safety must be strict enough to have great implications over the present work culture. A great organization has different degrees of satisfactions. According to many motivational

The Effects of the governmental mandatory furlough policy on employees Essay

The Effects of the governmental mandatory furlough policy on employees in Michigan - Essay Example These policies additionally state that employees who are not subject to any collective bargaining contracts when being employed are also subject to abrupt dismissal from employment (Morris, 2005). However, the employees may lay claims against discrimination in their employment on civil rights grounds. Discrimination based on gender, race, age, disability or religions has been prohibited by the federal and state laws in America (Schoeni, 2010). These laws state that the employers may dismiss employees who violate the lawful discharge of their duties, refuse to violate a law in the course of their employment or as an exercise of the rights that have been conferred on them (Kingdon & Thurber, 2010). Furlough programs that are mandatory within the state of Michigan have been implemented for the purpose of addressing the budget shortfalls that have faced the city (Bureau of National Affairs, 2009). There are employers who are legible for the mandatory furlough programs from the government while others are ineligible (Morris, 2005). There are several disadvantages and advantages that the employees within the state of Michigan have encountered due to the mandatory furlough programs that the government has introduced. An employee may take any benefits that have been accorded to him without being interrupted by the days that have been set for mandatory furlough. In addition, their health and dental insurances are also unaffected by these mandatory days (Kingdon & Thurber, 2010). The employees within the state of Michigan are allowed to receive holiday pays under these mandatory programs as though they were performing their regular duties at the workplace (Bureau of National Affairs, 2009). The time that employees serve on mandatory furlough is considered as though they were on regular duty when their benefits under their life insurance schemes are being

D. Forecast for Next 12-18 months Essay Example for Free

D. Forecast for Next 12-18 months Essay The world economic outlook is bright. World GDP growth is forecast to average slightly more than 4 percent per annum during 2006-2007. Asia will continue to act as the primary engine of global growth, though activity will also be supported by continued U. S. economic expansion of almost 3 percent annually. China will continue to register robust growth of slightly more than 9 percent per annum, and output will continue to increase rapidly also in India. Japan also appears to be entering a longer phase of stable growth. The positive global environment will be reinforced by the Euro Area, where economic growth is forecast to accelerate in response to a recovery in domestic demand (The Research Institute of the Finnish Economy). The National Institute of Economic and Social Research has recently released a set of forecasts regarding the state of world economy in 2007. Below are listed some of the key points: Global growth will quicken to 5. 1 per cent this year falling back only a bit in 2007 to a still rapid 4. 7 per cent. Inflationary pressures are rising, mainly owing to higher oil prices, but the impact of rising oil prices on inflation and output is now more muted than in the past. Global imbalances remain marked and the dollar may have to fall by a further 30 per cent in order to halve the US current-account deficit. The US economy will grow by over 3 per cent a year in both 2006 and 2007, but inflationary pressures are mounting. The Japanese economic recovery has become self-sustaining and GDP will rise by 3. 1 per cent in 2006 and by 2. 6 per cent in 2007. The Euro Area will expand by around 2 per cent a year in both 2006 and 2007, and consumer price inflation will average about 2. 5 per cent in both years. The NIESR report goes on to elaborate upon the aforementioned points: Advanced countries in the OECD bloc are participating in the upswing but the main reason for the current period of exceptionally strong global growth is the long boom in China. In 2005, China represented 15. 4 per cent of global GDP on a purchasing-power parity basis, up from 3. 4 per cent in 1980. Global inflation is rising in response to higher oil prices, but much less so than in the past. New estimates suggest that a $10 permanent rise in oil prices will add 0. 2 to 0. 4 percentage points to inflation in the United States in the four years to 2009, with a somewhat smaller impact in the Euro Area, and a still smaller effect in the UK. The global upswing continues to be accompanied by major imbalances, notably the scale of the US current account deficit, which widened by 4. 5 percentage points of GDP between 1997 and 2005. Since this deterioration has mainly financed increased consumer spending rather than productive investment, financial markets may conclude that the deficit is not sustainable. It is estimated that the dollar’s value against a basket of currencies needs to fall by a further 30 per cent in order to reduce the current account deficit by 3 percentage points of GDP. The US economy will grow by 3. 6 per cent in 2006 and by 3. 1 per cent in 2007. The economy continues to be driven mainly by consumption, which will increase by 3. 3 per cent in 2006 and by 2. 9 per cent in 2007. Housing investment is slackening but business investment, stimulated by high corporate profits, will buoy growth this year and next. Inflation is picking up and the private consumption deflator will rise by 3. 0 per cent in 2006 and by 3. 3 per cent in 2007. There now appears little doubt that the Japanese recovery from the bleak period of deflation and stagnation has become self-sustaining. The economy grew by 3. 5 per cent in the year to the first quarter of 2006 . Business investment is expanding strongly and consumer spending is expected to grow by 1. 9 per cent a year in 2006 and 2007. Average earnings, which had been falling earlier in the decade, will grow by 0. 8 per cent in 2006 and by 2. 8 per cent in 2007. The outlook for the Euro Area is for higher inflation despite a fairly modest recovery. Consumer prices will rise by 2. 6 per cent in 2006 compared with 2. 2 per cent in 2005. Tighter monetary conditions together with measures in Germany to cut the budget deficit will hold back growth in consumption and GDP in the Euro Area. Consumer spending will also be restrained by sluggish growth in average earnings as the corporate sector manages to retain its increased profitability (Barrell et al, 8-31).

The Book of Genesis Essay -- Bible Religion Papers

The Book of Genesis Genesis tells us that; in the beginning, God created the heavens, separated light from dark, and gave earth life. God also created two trees in the Garden of Eden. One was the â€Å"tree of life† and the other was the â€Å"tree of the knowledge of good and evil.† Adam was given life for the first time, and as a special gift, God created Eve. Moreover, God gave mankind freewill, allowing them to do whatever they pleased, so although God had forbidden Adam and Eve to touch the tree of knowledge of good and evil, He knew that it was their own choice whether or not to obey Him. In the story of the First Sin we see this first sign of LUST. lust n. Intense or unrestrained sexual craving. An overwhelming desire or craving: a lust for power. Intense eagerness or enthusiasm: a lust for life. The crafty serpent convinced Eve into eating the forbidden fruit by telling her, â€Å"You will not die; for God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil† (Genesis 3.4). Eve was curious to know what this â€Å"evil† was, and hence she lusted for knowledge to be powerful like the almighty God. Eve took her chances and put her faith in the serpent and not the Lord. After she ate the forbidden fruit, she offered it to her husband who was also curious as to what it would do to them. Now the Lord came down to confront Adam, and for the first time, Adam was afraid and hid. They were punished accordingly and now had to live knowing the darker half to life -- evil. wrath n. Forceful, often vindictive anger. Punishment or vengeance as a manifestation of anger. Divine retribution for sin... ... because he was Jacob’s favorite son. envy n. A feeling of discontent and resentment aroused by and in conjunction with desire for the possessions or qualities of another. Anyone would have loved to take his place, but there was no separating Joseph from his father. The envious brothers got together and conspired to kill him, but instead ended up selling their youngest sibling to slavery. In the end, Joseph prospered while all the others ended up where they started; envying their brother. As you can see, the original examples of each of the Deadly Sins are present in Genesis. From the beginning, we read about Lust in the story of Adam and Eve and end up with a story about Envy in Joseph and his brothers. Today, modern day people have to deal with choices between good and evil just like the times of Adam and Eve.

Steam Jet Refrigeration Cycle

Chemical Engineering and Processing 41 (2002) 551– 561 www. elsevier. com/locate/cep Evaluation of steam jet ejectors Hisham El-Dessouky *, Hisham Ettouney, Imad Alatiqi, Ghada Al-Nuwaibit Department of Chemical Engineering, College of Engineering and Petroleum, Kuwait Uni6ersity, P. O. Box 5969, Safat 13060, Kuwait Received 4 April 2001; received in revised form 26 September 2001; accepted 27 September 2001 Abstract Steam jet ejectors are an essential part in refrigeration and air conditioning, desalination, petroleum re? ning, petrochemical and chemical industries.The ejectors form an integral part of distillation columns, condensers and other heat exchange processes. In this study, semi-empirical models are developed for design and rating of steam jet ejectors. The model gives the entrainment ratio as a function of the expansion ratio and the pressures of the entrained vapor, motive steam and compressed vapor. Also, correlations are developed for the motive steam pressure a t the nozzle exit as a function of the evaporator and condenser pressures and the area ratios as a function of the entrainment ratio and the stream pressures. This allows for full design of the ejector, where de? ing the ejector load and the pressures of the motive steam, evaporator and condenser gives the entrainment ratio, the motive steam pressure at the nozzle outlet and the cross section areas of the diffuser and the nozzle. The developed correlations are based on large database that includes manufacturer design data and experimental data. The model includes correlations for the choked ? ow with compression ratios above 1. 8. In addition, a correlation is provided for the non-choked ? ow with compression ratios below 1. 8. The values of the coef? cient of determination (R 2) are 0. 85 and 0. 78 for the choked and non-choked ? w correlations, respectively. As for the correlations for the motive steam pressure at the nozzle outlet and the area ratios, all have R 2 values above 0. 99.  © 2002 Elsevier Science B. V. All rights reserved. Keywords: Steam jet ejectors; Choked ? ow; Heat pumps; Thermal vapor compression 1. Introduction Currently, most of the conventional cooling and refrigeration systems are based on mechanical vapor compression (MVC). These cycles are powered by a high quality form of energy, electrical energy. The inef? cient use of the energy required to operate such a process can be generated by the combustion of fossil uels and thus contributes to an increase in greenhouse gases and the generation of air pollutants, such as NOx, SOx, particulates and ozone. These pollutants have adverse effects on human health and the environment. In addition, MVC refrigeration and cooling cycles use unfriendly chloro-? oro-carbon compounds (CFCs), which, upon release, contributes to the destruction of the protective ozone layer in the upper atmosphere. * Corresponding author. Tel. : + 965-4811188Ãâ€"5613; fax: + 9654839498. E -mail address: [email  pro tected] kuniv. edu. kw (H. El-Dessouky). Environmental considerations and the need for ef? cient se of available energy call for the development of processes based on the use of low grade heat. These processes adopt entrainment and compression of low pressure vapor to higher pressures suitable for different systems. The compression process takes place in absorption, adsorption, chemical or jet ejector vapor compression cycles. Jet ejectors have the simplest con? guration among various vapor compression cycles. In contrast to other processes, ejectors are formed of a single unit connected to tubing of motive, entrained and mixture streams. Also, ejectors do not include valves, rotors or other moving parts and are available ommercially in various sizes and for different applications. Jet ejectors have lower capital and maintenance cost than the other con? gurations. On the other hand, the main drawbacks of jet ejectors include the following: ? Ejectors are designed to operate at a sin gle optimum point. Deviation from this optimum results in dramatic deterioration of the ejector performance. 0255-2701/02/$ – see front matter  © 2002 Elsevier Science B. V. All rights reserved. PII: S 0 2 5 5 – 2 7 0 1 ( 0 1 ) 0 0 1 7 6 – 3 552 ? H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 Ejectors have very low thermal ef? iency. Applications of jet ejectors include refrigeration, air conditioning, removal of non-condensable gases, transport of solids and gas recovery. The function of the jet ejector differs considerably in these processes. For example, in refrigeration and air conditioning cycles, the ejector compresses the entrained vapor to higher pressure, which allows for condensation at a higher temperature. Also, the ejector entrainment process sustains the low pressure on the evaporator side, which allows evaporation at low temperature. As a result, the cold evaporator ? uid can be used for refrigeration an d cooling functions.As for the removal of non-condensable gases in heat transfer units, the ejector entrainment process prevents their accumulation within condensers or evaporators. The presence of non-condensable gases in heat exchange units reduces the heat transfer ef? ciency and increases the condensation temperature because of their low thermal conductivity. Also, the presence of these gases enhances corrosion reactions. However, the ejector cycle for cooling and refrigeration has lower ef? ciency than the MVC units, but their merits are manifested upon the use of low grade energy that has limited effect on the environment and lower ooling and heating unit cost. Although the construction and operation principles of jet ejectors are well known, the following sections provide a brief summary of the major features of ejectors. This is necessary in order to follow the discussion and analysis that follow. The conventional steam jet ejector has three main parts: (1) the nozzle; (2) t he suction chamber; and (3) the diffuser (Fig. 1). The nozzle and the diffuser have the geometry of converging/diverging venturi. The diameters and lengths of various parts forming the nozzle, the diffuser and the suction chamber, together with the stream ? ow rate and properties, de? e the ejector capacity and performance. The ejector capacity is de? ned in terms of the ? ow rates of the motive steam and the entrained vapor. The sum of the motive and entrained vapor mass ? ow rates gives the mass ? ow rate of the compressed vapor. As for the ejector performance, it is de? ned in terms of entrainment, expansion and compression ratios. The entrainment ratio (w ) is the ? ow rate of the entrained vapor Fig. 1. Variation in stream pressure and velocity as a function of location along the ejector. H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 divided by the flow rate of the motive steam.As for the expansion ratio (Er), it is de? ned as the ratio of the motive steam pressure to the entrained vapor pressure. The compression ratio (Cr) gives the pressure ratio of the compressed vapor to the entrained vapor. Variations in the stream velocity and pressure as a function of location inside the ejector, which are shown in Fig. 1, are explained below: ? The motive steam enters the ejector at point (p ) with a subsonic velocity. ? As the stream ? ows in the converging part of the ejector, its pressure is reduced and its velocity increases. The stream reaches sonic velocity at the nozzle throat, where its Mach number is equal to one. The increase in the cross section area in the diverging part of the nozzle results in a decrease of the shock wave pressure and an increase in its velocity to supersonic conditions. ? At the nozzle outlet plane, point (2), the motive steam pressure becomes lower than the entrained vapor pressure and its velocity ranges between 900 and 1200 m/s. ? The entrained vapor at point (e ) enters the ejector, wher e its velocity increases and its pressure decreases to that of point (3). ? The motive steam and entrained vapor streams may mix within the suction chamber and the converging section of the diffuser or it may ? ow as two separate treams as it enters the constant cross section area of the diffuser, where mixing occurs. ? In either case, the mixture goes through a shock inside the constant cross section area of the diffuser. The shock is associated with an increase in the mixture pressure and reduction of the mixture velocity to subsonic conditions, point (4). The shock occurs because of the back pressure resistance of the condenser. ? As the subsonic mixture emerges from the constant cross section area of the diffuser, further pressure increase occurs in the diverging section of the diffuser, where part of the kinetic energy of the mixture is converted into pressure.The pressure of the emerging ? uid is slightly higher than the condenser pressure, point (c ). Summary for a number of literature studies on ejector design and performance evaluation is shown in Table 1. The following outlines the main ? ndings of these studies: ? Optimum ejector operation occurs at the critical condition. The condenser pressure controls the location of the shock wave, where an increase in the condenser pressure above the critical point results in a rapid decline of the ejector entrainment ratio, since the shock wave moves towards the nozzle exit.Operating at pressures below the critical points has negligible effect on the ejector entrainment ratio. 553 ? At the critical condition, the ejector entrainment ratio increases at lower pressure for the boiler and condenser. Also, higher temperature for the evaporator increases the entrainment ratio. ? Use of a variable position nozzle can maintain the optimum conditions for ejector operation. As a result, the ejector can be maintained at critical conditions even if the operating conditions are varied. ? Multi-ejector system increases the operating range and improves the overall system ef? ciency. Ejector modeling is essential for better understanding of the compression process, system design and performance evaluation. Models include empirical correlations, such as those by Ludwig [1], Power [2] and El-Dessouky and Ettouney [3]. Such models are limited to the range over which it was developed, which limits their use in investigating the performance of new ejector ? uids, designs or operating conditions. Semi-empirical models give more ? exibility in ejector design and performance evaluation [4,5]. Other ejector models are based on fundamental balance equations [6]. This study is motivated by the need for a simple mpirical model that can be used to design and evaluate the performance of steam jet ejectors. The model is based on a large database extracted from several ejector manufacturers and a number of experimental literature studies. As will be discussed later, the model is simple to use and it eliminates the need for iterative procedures. 2. Mathematical model The review by Sun and Eames [7] outlined the developments in mathematical modeling and design of jet ejectors. The review shows that there are two basic approaches for ejector analysis. These include mixing of the motive steam and entrained vapor, either at constant ressure or at constant area. Design models of stream mixing at constant pressure are more common in literature because the performance of the ejectors designed by this method is more superior to the constant area method and it compares favorably against experimental data. The basis for modeling the constant pressure design procedure was initially developed by Keenan [6]. Subsequently, several investigators have used the model for design and performance evaluation of various types of jet ejectors. This involved a number of modi? cations in the model, especially losses within the ejector and mixing of the primary and secondary streams.In this section, the constant pressure e jector model is developed. The developed model is based on a number of literature studies [8 – 11]. The constant pressure model is based on the following assumptions: H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 554 Table 1 Summary of literature studies on ejector design and performance Reference Fluid Boiler, evaporator and condenser temperature ( °C) Conclusion [19] R-113 60–100; 5–18; 40–50 Basis for refrigerant selection for solar system, system performance increased with increasing boiler and evaporator temperatures and decreasing condenser temperature. 20] R-113; R-114; R-142b; R-718 80–95; 5–13; 25–45 Comparison of ejector and refrigerant performance. Dry, wet and isentropic ?uids. Wet ? uid damage ejectors due phase change during isentropic expansion. R-113 (dry) has the best performance and R142b (wet) has the poorest performance. [21,22] R-114 86; ? 8; 30 Increase in ejector perfo rmance using mechanical compression booster. [8] Water 120–140; 5–10; 30–65 Choking of the entrained ? uid in the mixing chamber affects system performance. Maximum COP is obtained at the critical ? ow condition. [13] Water 120–140; 5–10; 30–60Effect of varying the nozzle position to meet operating condition. Increase in COP and cooling capacity by 100%. [23] R-113 70–100; 6–25; 42–50 Entrainment ratio is highly affected by the condenser temperature especially at low evaporator temperature. [24] R-11 82. 2–182. 2; 10; 43. 3 Entrainment ratio is proportional to boiler temperature. [25,26] R-114 90; 4; 30 Combined solar generator and ejector air conditioner. More ef? cient system requires multi-ejector and cold energy storage (cold storage in either phase changing materials, cold water or ice). [27] R-134A 15; 30 Modeling the effect of motive nozzle on system performance, in which the ejector is used to recover part of the work that would be lost in the expansion valve using high-pressure motive liquid. [28] Water 100–165; 10; 30–45 Combined solar collector, refrigeration and seawater desalination system. Performance depends on steam pressure, cooling water temperature and suction pressure. [4] Water [29] Water – Model of multistage steam ejector refrigeration system using annular ejector in which the primary ? uid enters the second stage at annular nozzle on the sidewall.This will increase static pressure for low-pressure stream and mixture and reduce the velocity of the motive stream and reduce jet mixing losses shock wave formation losses. [24] R11; R113; R114 93. 3; 10; 43. 3 Measure and calculate ejector entrainment ratio as a function of boiler, condenser and evaporator temperatures. Entrainment ratio decreases for off design operation and increases for the two stage ejectors. [30] R113; R114; R142b 120–140; 65–80 Effect of throat area, location of main nozzle and length of the constant area section on backpressure, entrainment ratio and compression ratio.Developed a new ejector theory in which the entrained ? uid is choked, the plant scale results agree with this theory. Steam jet refrigeration should be designed for the most often prevailing conditions rather than the most severe to achieve greater overall ef? ciency. [5] Mathematical model use empirical parameters that depend solely on geometry. The parameters are obtained experimentally for various types of ejectors. [31] R134a 5; ? 12, ? 18; 40 Combined ejector and mechanical compressor for operation of domestic refrigerator-freezer increases entrainment ratio from 7 to 12. 4%. The optimum throat diameter depends on the freezer emperature [9] R11; HR-123 80; 5; 30 Performance of HR-123 is similar to R-11 in ejector refrigeration. Optimum performance is achieved by the use of variable geometry ejector when operation conditions change. H. El -Dessouky et al. / Chemical Engineer ing and Processing 41 (2002) 551 – 561 1. The motive steam expands isentropically in the nozzle. Also, the mixture of the motive steam and the entrained vapor compresses isentropically in the diffuser. 2. The motive steam and the entrained vapor are saturated and their velocities are negligible. 3. Velocity of the compressed mixture leaving the ejector is insigni? cant. 4.Constant isentropic expansion exponent and the ideal gas behavior. 5. The mixing of motive steam and the entrained vapor takes place in the suction chamber. 6. The ? ow is adiabatic. 7. Friction losses are de? ned in terms of the isentropic ef? ciencies in the nozzle, diffuser and mixing chamber. 8. The motive steam and the entrained vapor have the same molecular weight and speci? c heat ratio. 9. The ejector ? ow is one-dimensional and at steady state conditions. The model equations include the following: ? Overall material balance (2) Expansion ratio ? ‘ 2pn k? 1   Pp P2 n (k ? 1/k) ?1 Pe P2 n (k ? 1/k) ?1 (6) M*2 + wM*2Te/Tp p e ‘ M 2(k + 1) M 2(k ? 1) + 2 (8) Eq. (8) is used to calculate M*2, M*2, M4 e p Mach number of the mixed ? ow after the shock wave 2 M2+ 4 (k ? 1) M5 = (9) 2k 2 M ? 1 (k ? 1) 4 Pressure increase across the shock wave at point 4 (10) In Eq. (10) the constant pressure assumption implies that the pressure between points 2 and 4 remains constant. Therefore, the following equality constraint applies P2 = P3 = P4. Pressure lift in the diffuser  n Pc p (k ? 1) 2 =d M5+1 P5 2 ? (5) ? (k/k ? 1) (11) where pd is the diffuser ef? ciency. The area of the nozzle throat A1 = where M is the Mach number, P is the pressure and is the isentropic expansion coef? cient. In the above equation, pn is the nozzle ef? ciency and is de? ned as the ratio between the actual enthalpy change and the enthalpy change undergone during an isentropic process. Isentropic expansion of the entrained ? uid in the suction chamber is expressed in terms of the Mach number of the entrai ned ? uid at the nozzle exit plane   P5 1 + kM 2 4 = P4 1 + kM 2 5 (4) Isentropic expansion of the primary ? uid in the nozzle is expressed in terms of the Mach number of the primary ? uid at the nozzle outlet plane Mp2 = ? ? (3) Er = Pp/Pe ? ? 2 k? 1 (7) (1 + w )(1 + wTe/Tp) here w is the entrainment ratio and M * is the ratio between the local ? uid velocity to the velocity of sound at critical conditions. The relationship between M and M * at any point in the ejector is given by this equation M* = Compression ratio Cr = Pc/Pe ? ? ‘ The mixing process is modeled by one-dimensional continuity, momentum and energy equations. These equations are combined to de? ne the critical Mach number of the mixture at point 5 in terms of the critical Mach number for the primary and entrained ?uids at point 2 M* = 4 where m is the mass ? ow rate and the subscripts c, e and p, de? ne the compressed vapor mixture, the ntrained vapor and the motive steam or primary stream. Entrainment ratio w = me/mp ? ? (1) mp + me = mc ? Me2 = 555 mp Pp ‘ RTp k + 1 kpn 2 (k + 1)/(k ? 1) (12) The area ratio of the nozzle throat and diffuser constant area        A1 Pc 1 = A3 Pp (1 + w )(1 + w (Te/Tp)) P2 1/k P (k ? 1)/k 1/2 1? 2 Pc Pc 2 1/(k ? 1) 2 1/2 1? k+1 k+1 1/2 (13) H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 556 ? The area ratio of the nozzle throat and the nozzle outlet A2 = A1 ‘  1 2 (k ? 1) 2 1+ M p2 2 M p2 (k + 1 2  ? (k + 1)/(k ? 1) (14) ? 3. Solution procedure ?Two solution procedures for the above model are shown in Fig. 2. Either procedure requires iterative calculations. The ? rst procedure is used for system design, where the system pressures and the entrainment ratio is de? ned. Iterations are made to determine the pressure of the motive steam at the nozzle outlet (P2) that gives the same back pressure (Pc). The iteration sequence for this procedure is shown in Fig. 2(a) and it includes the fol lowing steps: ? De? ne the design parameters, which include the entrainment ratio (w ), the ? ow rate of the compressed ? ? ? ? vapor (mc) and the pressures of the entrained vapor, ompressed vapor and motive steam (Pe, Pp, Pc). De? ne the ef? ciencies of the nozzle and diffuser (pn, pd). Calculate the saturation temperatures for the compressed vapor, entrained vapor and motive steam, which include Tc, Tp, Te, using the saturation temperature correlation given in the appendix. As for the universal gas constant and the speci? c heat ratio for steam, their values are taken as 0. 462 and 1. 3. The ? ow rates of the entrained vapor (me) and motive steam (mp) are calculated from Eqs. (1) and (2). A value for the pressure at point 2 (P2) is estimated and Eqs. (5) – (11) are solved sequentially to obtain the ressure of the compressed vapor (Pc). The calculated pressure of the compressed vapor is compared to the design value. A new value for P2 is estimated and the previous step is re peated until the desired value for the pressure of the compressed vapor is reached. Fig. 2. Solution algorithms of the mathematical model. (a) Design procedure to calculate area ratios. (b) Performance evaluation to calculate w. H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 ? The ejector cross section areas (A1, A2, A3) and the area ratios (A1/A3 and A2/A1) are calculated from Eqs. (12) – (14).The second solution procedure is used for performance evaluation, where the cross section areas and the entrainment and motive steam pressures are de? ned. Iterations are made to determine the entrainment ratio that de? nes the ejector capacity. The iteration sequence for this procedure is shown in Fig. 2(b) and it includes the following steps: ? De? ne the performance parameters, which include the cross section areas (A1, A2, A3), the pressures of the entrained vapor (Pe) and the pressure of the primary stream (Pp). ? De? ne the ef? ciencies of the nozzle and diffuser (pn, pd). ? Calculate the saturation temperatures of the primary nd entrained streams, Tp and Te, using the saturation temperature correlation given in the appendix. ? As for the universal gas constant and the speci? c heat ratio for steam, their values are taken as 0. 462 and 1. 3. ? Calculate the ? ow rate of the motive steam and the properties at the nozzle outlet, which include mp, P2, Me2, Mp2. These are obtained by solving Eqs. (5), (6), (12) and (14). ? An estimate is made for the entrainment ratio, w. ? This value is used to calculate other system parameters de? ned in Eqs. (7) – (11), which includes M*2, e M*2, M*, M4, M5, P5, Pc. p 4 ? A new estimate for w is obtained from Eq. 13). ? The error in w is determined and a new iteration is made if necessary. ? The ? ow rates of the compressed and entrained vapor are calculated from Eqs. (1) and (2). 4. Semi-empirical model Development of the semi-empirical model is thought to provide a simple met hod for designing or rating of steam jet ejectors. As shown above, solution of the mathematical model requires an iterative procedure. Also, it is necessary to de? ne values of pn and pd. The values of these ef? ciencies widely differ from one study to another, as shown in Table 2. The semi-empirical model for the steam jet ejector is developed over a wide ange of operating conditions. This is achieved by using three sets of design data acquired from major ejector manufacturers, which includes Croll Reynolds, Graham and Schutte – Koerting. Also, several sets of experimental data are extracted from the literature and are used in the development of the empirical model. The semiempirical model includes a number of correlations to calculate the entrainment ratio (w ), the pressure at the nozzle outlet (P2) and the area ratios in the ejector 557 Table 2 Examples of ejector ef? ciencies used in literature studies Reference [27] [32] [33] [31] [10] [24] [8] [34] pn pd 0. 9 0. 5 0. 7 –1 0. 8–1 0. 85–0. 98 0. 85 0. 75 0. 75 0. 8 0. 85 0. 7–1 0. 8–1 0. 65–0. 85 0. 85 0. 9 pm 0. 8 0. 95 (A2/A1) and (A1/A3). The correlation for the entrainment ratio is developed as a function of the expansion ratio and the pressures of the motive steam, the entrained vapor and the compressed vapor. The correlation for the pressure at the nozzle outlet is developed as a function of the evaporator and condenser pressures. The correlations for the ejector area ratios are de? ned in terms of the system pressures and the entrainment ratio. Table 3 shows a summary of the ranges of the experimental and the design data.The table also includes the ranges for the data reported by Power [12]. A summary of the experimental data, which is used to develop the semi-empirical model is shown in Table 4. The data includes measurements by the following investigators: ? Eames et al. [8] obtained the data for a compression ratio of 3 – 6, expansion ratio 160 – 415 and entrainment ratio of 0. 17 – 0. 58. The measurements are obtained for an area ratio of 90 for the diffuser and the nozzle throat. ? Munday and Bagster [4] obtained the data for a compression ratio of 1. 8 – 2, expansion ratio of 356 – 522 and entrainment ratio of 0. 57 – 0. 905.The measurements are obtained for an area ratio of 200 for the diffuser and the nozzle throat. ? Aphornratana and Eames [13] obtained the data for a compression ratio of 4. 6 – 5. 3, expansion ratio of 309. 4 and entrainment ratio of 0. 11 – 0. 22. The measurements are obtained for an area ratio of 81 for the diffuser and the nozzle throat. ? Bagster and Bresnahan [14] obtained the data for a compression ratio of 2. 4 – 3. 4, expansion ratio of 165 – 426 and entrainment ratio of 0. 268 – 0. 42. The measurements are obtained for an area ratio of 145 for the diffuser and the nozzle throat. ? Sun [15] obtained the data for a comp ression ratio of . 06 – 3. 86, expansion ratio of 116 – 220 and entrainment ratio of 0. 28 – 0. 59. The measurements are obtained for an area ratio of 81 for the diffuser and the nozzle throat. ? Chen and Sun [16] obtained the data for a compression ratio of 1. 77 – 2. 76, expansion ratio of 1. 7 – 2. 9 and entrainment ratio of 0. 37 – 0. 62. The measure- H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 558 ments are obtained for an area ratio of 79. 21 for the diffuser and the nozzle throat. ? Arnold et al. [17] obtained the data for a compression ratio of 2. 47 – 3. 86, expansion ratio of 29. 7 – 46. , and entrainment ratio of 0. 27 – 0. 5. ? Everitt and Riffat [18] obtained the data for a compression ratio of 1. 37 – 2. 3, expansion ratio of 22. 6 – 56. 9 and entrainment ratio of 0. 57. The correlation for the entrainment ratio of choked ?ow or compression ratios ab ove 1. 8 is given by W = aErbP cP d ec (e + fP g ) p (h + iP jc) (15) Similarly, the correlation for the entrainment ratio of un-choked ? ow with compression ratios below 1. 8 is given by W = aErbP cP d ec (e + f ln(Pp)) (g + h ln(Pc)) (16) vapor compression applications. As shown in Fig. 3, the ? tting result is very satisfactory for entrainment ratios between 0. 2 and 1.This is because the major part of the data is found between entrainment ratios clustered over a range of 0. 2 – 0. 8. Examining the experimental data ? t shows that the major part of the data ? t is well within the correlation predictions, except for a small number of points, where the predictions have large deviations. The correlations for the motive steam pressure at the nozzle outlet and the area ratios are obtained semi-empirically. In this regard, the design and experimental data for the entrainment ratio and system pressures are used to solve the mathematical model and to calculate the area ratios and motive steam pressure at the nozzle utlet. The results are obtained for ef? ciencies of 100% for the diffuser, nozzle and mixing and a value of 1. 3 for k. The results are then correlated as a function of the system variables. The following relations give the correlations for the choked ? ow: The constants in Eqs. (15) and (16) are given as follows P2 = 0. 13 P 0. 33P 0. 73 e c (17) A1/A3 = 0. 34 P 1. 09P ? 1. 12w ? 0. 16 c p Entrainment ratio Entrainment ratio correlation choked correlation non-choked ?ow (Eq. (15); Fig. 3) ? ow (Eq. (16), Fig. 4) ?1. 89? 10? 5 ?5. 32 5. 04 9. 05? 10? 2 22. 09 ?6. 13 0. 82 ?3. 37? 10? 5 ? ? 0. 79 a 0. 65 b ?1. 54 c 1. 72 d 6. 9v10? 2 e 22. 82 f 4. 21? 10? 4 g 1. 34 h 9. 32 j 1. 28? 10? 1 j 1. 14 R2 0. 85 A2/A1 = 1. 04 P ? 0. 83 c P 0. 86 p w (18) ? 0. 12 (19) The R 2 for each of the above correlations is above 0. 99. Similarly, the following relations give the correlations for the un-choked ? ow: P2 = 1. 02 P ? 0. 000762P 0. 99 e c (20) A1/A3 = 0. 32 P 1. 11P ? 1. 13w ? 0. 36 c p (21) A2/A1 = 1. 22 P ? 0. 81P 0. 81w ? 0. 0739 c p (22) 2 Fitting results against the design and experimental data are shown in Figs. 3 and 4, respectively. The results shown in Fig. 3 cover the most commonly used range for steam jet ejectors, especially in vacuum andThe R values for the above three correlations are above 0. 99. The semi-empirical ejector design procedure involves sequential solution of Eqs. (1) – (14) together with Eq. (17) or Eq. (20) (depending on the ? ow type, choked or non-choked). This procedure is not iterative in contrast with the procedure given for the mathematical model in the previous section. As for the semi-empirical performance evaluation model, it involves non-iterative solution of Eqs. (1) – (14) together with Eq. (15) or Eq. (16) for choked or non-choked ? ow, respectively. It should be stressed that both solution procedures are indepen- Table 3Range of design and experimental data used in model devel opment Source Er Cr Pe (kPa) Pc (kPa) Pp (kPa) w Experimental Schutte–Koerting Croll–Rynolds Graham Power 1. 4–6. 19 1. 008–3. 73 1. 25–4. 24 1. 174–4. 04 1. 047–5. 018 1. 6–526. 1 1. 36–32. 45 4. 3–429. 4 4. 644–53. 7 2–1000 0. 872–121. 3 66. 85–2100. 8 3. 447–124. 1 27. 58–170. 27 2. 76–172. 37 2. 3–224. 1 790. 8–2859. 22 446. 06–1480. 27 790. 8–1480. 27 3. 72–510. 2 38. 6–1720 84. 09–2132. 27 6. 2–248. 2 34. 47–301. 27 344. 74–2757. 9 0. 11–1. 132 0. 1–4 0. 1818–2. 5 0. 18–3. 23 0. 2–4 H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 559 Table 4Summary of literature experimental data for steam jet ejectors Ad/At Pp (kPa) Pe (kPa) Pc (kPa) Pp/Pe Pc/Pe w Reference 90 198. 7 232. 3 270. 3 313. 3 361. 6 1. 23 1. 23 1. 23 1. 2 3 1. 23 3. 8 4. 2 4. 7 5. 3 6 161. 8 189. 1 220. 1 255. 1 294. 4 3. 09 3. 42 3. 83 4. 31 4. 89 0. 59 0. 54 0. 47 0. 39 0. 31 [8] [8] [8] [8] [8] 90 198. 7 232. 3 270. 3 313. 3 361. 6 1. 04 1. 04 1. 04 1. 04 1. 04 3. 6 4. 1 4. 6 5. 1 5. 7 191. 6 223. 9 260. 7 302. 1 348. 7 3. 47 3. 95 4. 44 4. 91 5. 49 0. 5 0. 42 0. 36 0. 29 0. 23 [8] [8] [8] [8] [8] 90 198. 7 232. 3 270. 3 313. 3 361. 6 0. 87 0. 87 0. 87 0. 87 0. 87 3. 4 3. 7 4. 4 5. 1 5. 4 227. 7 266. 2 309. 8 59 414. 4 3. 89 4. 24 5. 04 5. 85 6. 19 0. 4 0. 34 0. 28 0. 25 0. 18 [8] [8] [8] [8] [8] 200 834 400 669 841 690 690 1. 59 1. 59 1. 71 1. 59 1. 94 1. 94 3. 2 3. 07 3. 67 3. 51 3. 38 3. 51 521. 7 250. 2 392. 3 526. 1 356 356 2. 0 1. 92 2. 15 2. 19 1. 74 1. 81 0. 58 1. 13 0. 58 0. 51 0. 86 0. 91 [4] [4] [4] [4] [4] [4] 81 270 270 270 270 270 0. 87 0. 87 0. 87 0. 87 0. 87 4. 1 4. 2 4. 4 4. 5 4. 7 309. 5 309. 5 309. 5 309. 5 309. 5 4. 7 4. 8 5. 04 5. 16 5. 39 0. 22 0. 19 0. 16 0. 14 0. 11 [13] [13] [13] [13] [13] 145 660 578 516 440 381 312 278 1. 55 1. 55 1. 58 1. 57 1. 59 1. 62 1. 68 5. 3 5. 3 5. 3 5. 03 4. 77 4. 23 4. 1 426. 5 373. 5 326. 280. 6 239. 9 192. 6 165. 1 3. 42 3. 42 3. 36 3. 21 3 2. 61 2. 44 0. 27 0. 31 0. 35 0. 38 0. 42 0. 46 0. 42 [14] [14] [14] [14] [14] [14] [14] 143. 4 169. 2 198. 7 232. 3 270. 3 1. 23 1. 23 1. 23 1. 23 1. 23 2. 53 2. 67 3. 15 4 4. 75 116. 8 137. 8 161. 8 189. 1 220. 1 2. 06 2. 17 2. 56 3. 26 3. 87 0. 59 0. 51 0. 43 0. 35 0. 29 [15] [15] [15] [15] [15] 29. 7 33. 5 37. 8 46. 5 2. 47 2. 78 3. 14 3. 86 0. 5 0. 4 0. 3 0. 27 [17] [17] [17] [17] 119. 9 151. 7 224. 1 195. 1 195. 1 186. 2 1. 7 2. 3 3. 9 1. 6 1. 9 2. 9 1. 8 2. 2 3. 3 1. 6 1. 9 2. 8 0. 62 0. 49 0. 34 0. 78 0. 64 0. 37 [16] [16] [16] [16] [16] [16] 2. 3 2. 3 2. 3 56. 9 38. 6 22. 6 . 3 1. 9 1. 4 0. 57 0. 56 0. 57 [18] [18] [18] 81 1720 1720 1720 1720 79. 21 116 153 270 198 198 198 57. 9 47. 4 38. 6 57. 7 51. 4 45. 5 37. 01 67. 6 67. 6 67. 6 121. 3 99. 9 67. 6 1. 02 1. 2 1. 7 143 143 143 143 560 H. El -Dessouky et al . / Chemical Engineering and Processing 41 (2002) 551 – 561 wide range of compression, expansion and entrainment ratios, especially those used in industrial applications. The developed correlations are simple and very useful for design and rating calculations, since it can be used to determine the entrainment ratio, which, upon speci? cation of the system load, can be used to determine the motive steam ? w rate and the cross section areas of the ejector. Acknowledgements Fig. 3. Fitting of the entrainment ratio for compression ratios higher than 1. 8. The authors would like to acknowledge funding support of the Kuwait University Research Administration, Project No. EC084 entitled ‘Multiple Effect Evaporation and Absorption/Adsorption Heat Pumps’. Appendix A. Nomenclature A COP Cr Er m M M* Fig. 4. Fitting of the entrainment ratio for compression ratios lower than 1. 8. dent of the nozzle and diffuser ef? ciencies, which varies over a wide range, as shown in Table 2. 5. Conclusions A semi-empirical model is developed for design and erformance evaluation of steam jet ejector. The model includes correlations for the entrainment ratio in choked and non-choked ? ow, the motive steam pressure at the nozzle outlet and the area ratios of the ejector. The correlations for the entrainment ratio are obtained by ? tting against a large set of design data and experimental measurements. In addition, the correlations for the motive steam pressure at the nozzle outlet and the area ratios are obtained semi-empirically by solving the mathematical model using the design and experimental data for the entrainment ratio and system pressures.The correlations cover a P DP R Rs T w cross section area (m2) coef? cient of performance, dimensionless compression ratio de? ned as pressure of compressed vapor to pressure of entrained vapor expansion ratio de? ned as pressure of compressed vapor to pressure of entrained vapor mass ? ow rate (kg/s) Mach number, ratio of ? uid velocity to speed of sound critical Mach number, ratio of ? uid velocity to speed of sound pressure (kPa) pressure drop (kPa) universal gas constant (kJ/kg  °C) load ratio, mass ? ow rate of motive steam to mass ? ow rate of entrained vapor temperature (K) ntrainment ratio, mass ? ow rate of entrained vapor to mass ? ow rate of motive steam Greek symbols k compressibility ratio p ejector ef? ciency Subscripts 1–7 locations inside the ejector b boiler c condenser d diffuser e evaporator or entrained vapor m mixing n nozzle p primary stream or motive steam t throat of the nozzle H. El -Dessouky et al. / Chemical Engineering and Processing 41 (2002) 551 – 561 Appendix B B. 1. Correlations of saturation pressure and temperature   The saturation temperature correlation is given by T = 42. 6776 ? 3892. 7 ? 273. 15 (ln(P /1000) ? 9. 48654) here P is in kPa and T is in  °C. The above correlation is valid for the calculated saturation temperature over a pressure range of 10 – 1750 kPa. The percentage errors for the calculated versus the steam table values are B 0. 1%. The correlation for the water vapor saturation pressure is given by  ln(P /Pc) = Tc ?1 T + 273. 15  8 ? % fi (0. 01(T + 273. 15 ? 338. 15))(i ? 1) i=1 where Tc = 647. 286 K and Pc = 22089 kPa and the values of fi are given in the following table f1 f2 f3 f4 ?7. 419242 0. 29721 ?0. 1155286 0. 008685635 f5 f6 f7 f8 0. 001094098 ?0. 00439993 0. 002520658 ?0. 000521868

Banks Mat Review Essay

Robert Banks and Bernice M. Ledbetter believe the subject of leadership to be one worth exploring, and they do so in their book much to our profit. In this short book, Banks and Ledbetter begin by presenting the overall question they want to answer: Do Christians’ core convictions shape their views and practices of leadership or are they affected by wider cultural assumptions? [1]The book begins by exploring the many reasons for the increased interest in leadership today. The authors offer a plethora of reasons, not withholding the greatly increased pace of change, and they also set out some other factors for understanding leadership, including the comparison and contrast between a ‘leader’ and the qualities of ‘leadership’. Banks and Ledbetter take great care to ask challenging questions. This practice aids in the development of the book. In the opening chapters they begin by defining leadership as involving a person, group, or organization who shows the way in an area of life. [2] The authors also provide a strong distinction between management and leadership while also showing the importance of these two roles to work together. The foundation of the writing is supported by the claims towards the importance  of the study of leadership. Banks and Ledbetter continue on to explore leadership in a wider range of historical and Biblical contexts. They work from religious and Christian perspectives and work outward towards cultural influences. The authors share insight as it relates to the biblical, historical and contemporary perspectives, covering the accounts of the Apostle Paul, historical models such as the Benedictine tradition, Lutheran, Presbyterian and Pentecostal. They continue by exploring trait, contingency and transformational leadership. Chapters three and four provide the most specific writings on the topic of leadership. In these chapters Banks and Ledbetter draw attention to the raw spiritual, theological, and religious concepts of leadership. Here the authors conduct a case study of a significant author of leadership material, Stephen Covey. It is revealed that many readers are influenced by his Mormon faith without truly understanding or discerning the undertones.[3] This continues with an exploration of other perceived authorities on the topic of leadership. One such study is of Laura Beth Jones, an woman writer with increasing influence as it relates to leadership. Chapter five addresses how to translate practices of leadership into individual context through the use of three basic yet important values: faithfulness, integrity, and a servant-like attitude. Exploration of these three traits is undergirder with discussion of authors such as Robert Greenleaf. He is one of many leaders who brought into popular leadership thinking the idea of ‘servant leadership’.The book closes by offering examples in the form of case-studies. These studies provide deeper insight into the foundational qualities of successful leaders over the span of several years and many different context. This offers the reader a broader view of leadership by showing its success in many different forms and context. CONCRETE RESPONSE While reading through each chapter I was challenged to consider the conflicts I have faced that came as the result of lacking a manager to accompany my leadership. As a pastor, I am a natural leader. I tend to seek out change while searching for ways to constantly make things better and more efficient. About two years ago I was in a conflict with several of the leaders in our church. The conflict revolved around our misunderstanding of  each others approach and roles in leadership. As an proponent of change, I was offended by their seeming lack of faith in pursuing a broader reach in ministry and our effectiveness in the community. As managers, they were more apt to move slowly and could only visualize the problems that would need to be addressed in order to achieve the vision that was laid forth by me. After studying the viewpoints of Banks and Ledbetter I can now see how we could have easily been on the same page and shared the same goal while simply looking from distinct perspectives. I have now began to wonder how many other relationships could have been mended by simply understanding the role that each party played. I have a tendency to assume that others will automatically view things in the same way that I have. This has often led to great disappointment or great feelings of being misunderstood. In this way my passion can easily become focused on the wrong thing and people could easily become the target of that passion. REFLECTION While the book does a great job of exploring the topic of leadership, because of the breadth and depth of the topic many questions remain. Taking into account the authors definitions of managers and leaders, how do the two roles successfully communicate their intentions to one another? It is very possible for the two roles to coexist with proper acknowledgment of one another. How do the two operate together effectively without disrespecting or disregarding the importance of each role. Also, how does one know which leadership style works best in a given context? Does it take an extended period of trial and error to discover the proper styles? How do followers or even managers respond to a constantly changing leadership style? This book could have been greatly improved with a more comprehensive study of the specified leadership topics. The writing feels much like a generic overview of very important topics. While well written and engaging, I am left wanting as it relates to determining how to not only incorporate the leadership styles but also choose the style that is most fitting. This book feels like a movie that ended too soon. Leaving readers wondering what do with the brief information provided. ACTION With a fresh view of the information given by Banks and Ledbetter, I now have the information needed to implement a healthier leadership style that includes a clarity of my role as an agent of change. This plan is broken into two distinct parts. First, to properly identify the contexts that guide the view of leadership within the leadership team of the church that I pastor. What types of leaders have they encountered in the past? Are they open to change or resistant to it? This objective will be accomplished through the scheduling of one on one meetings with each leader. These meeting will allow me the opportunity to engage each leader in a meaningful conversation about the leadership styles they are most comfortable with. With this information I will be equipped to better serve these leaders by communicating with them in a way that they are most likely to receive. This is based upon Banks and Ledbetters observation of the broad idea of leadership many people carry. Secondly, I will create a comprehensive list of the core beliefs that will guide our leadership team. For those considering becoming parts of our church, how do they know the values that determine our decision making as leaders? This list will answer that question. It will become the core values for current and even future leaders. This comprehensive list will incorporate biblical teachings from Jesus as well as the Apostle Paul’s qualifications from 1 Peter and the epistles to Timothy. By outlining these core values, we create accountability, an attribute that could also allow for congregants and members alike to feel more comfortable engaging with the vision of our church by being secure in the direction and the values that guide us. BIBLIOGRAPHY Banks, Robert and Ledbetter, Bernice â€Å"Reviewing Leadership: A Chriatian Evaluation of Current Approaches†, Grand Rapids, MI Baker Publishing Group 2004

Free Essays on The Importance Of The Boston Tea Party

Alfred Young describes the Boston Tea Party as â€Å"the most revolutionary act of the decade.† Indeed it was a very revolutionary act of the decade and it is considered to be one of the most revolutionary acts ever. To some people, however, the Boston Tea Party was not â€Å"the most revolutionary act of the decade.† This paper will analyze the Boston Tea Party and compare the opinions of Alfred Young and the author of this paper. The Boston Tea Party is a popular name for what took place on December 16, 1773. On the evening of December 16, a group of Boston citizens, led by Samuel Adams and many of them disguised as Indians, boarded the ships that brought the tea from Britain and emptied the tea into Boston Harbor. Although most provisions of the Townshend Acts, taxing imports to the colonies, were repealed by Parliament, the duty on tea was retained to demonstrate the power of Parliament to tax the colonies. The citizens of Boston would not permit the unloading of three British ships that arrived in Boston Harbor loaded with tea. The royal governor of Massachusetts, Thomas Hutchinson, however, would not let the tea ships return to England until the taxes had been paid. When the government of Boston refused to pay for the tea, the British closed the port. British parliament had passed the Boston Port Act in March 1774, in order to punish Boston for the dumping of the tea in Boston Harbor. The Boston Port Act is one of many of the Intolerable Acts. Provisions of the bill included the closing of Boston Harbor to all other business until the tax was paid and stripping the power of the government of the Massachusetts Bay Colony from Boston to Salem and replacing the leader with a crown appointed governor. British soldiers occupied Boston to enforce the new laws, and the harbor was blockaded. The surrounding New England towns also suffered from this because they heavily relied on Boston’s port for their goods and supplies. Towns in New ... Free Essays on The Importance Of The Boston Tea Party Free Essays on The Importance Of The Boston Tea Party Alfred Young describes the Boston Tea Party as â€Å"the most revolutionary act of the decade.† Indeed it was a very revolutionary act of the decade and it is considered to be one of the most revolutionary acts ever. To some people, however, the Boston Tea Party was not â€Å"the most revolutionary act of the decade.† This paper will analyze the Boston Tea Party and compare the opinions of Alfred Young and the author of this paper. The Boston Tea Party is a popular name for what took place on December 16, 1773. On the evening of December 16, a group of Boston citizens, led by Samuel Adams and many of them disguised as Indians, boarded the ships that brought the tea from Britain and emptied the tea into Boston Harbor. Although most provisions of the Townshend Acts, taxing imports to the colonies, were repealed by Parliament, the duty on tea was retained to demonstrate the power of Parliament to tax the colonies. The citizens of Boston would not permit the unloading of three British ships that arrived in Boston Harbor loaded with tea. The royal governor of Massachusetts, Thomas Hutchinson, however, would not let the tea ships return to England until the taxes had been paid. When the government of Boston refused to pay for the tea, the British closed the port. British parliament had passed the Boston Port Act in March 1774, in order to punish Boston for the dumping of the tea in Boston Harbor. The Boston Port Act is one of many of the Intolerable Acts. Provisions of the bill included the closing of Boston Harbor to all other business until the tax was paid and stripping the power of the government of the Massachusetts Bay Colony from Boston to Salem and replacing the leader with a crown appointed governor. British soldiers occupied Boston to enforce the new laws, and the harbor was blockaded. The surrounding New England towns also suffered from this because they heavily relied on Boston’s port for their goods and supplies. Towns in New ...

Using “Etcetera” in Academic Writing Blog at EssaySupply.com

Using â€Å"Etcetera† in Academic Writing Blog Using â€Å"Etcetera† in Academic Writing You probably know it better as â€Å"etc.† you have read things that have used it; you have probably said it yourself. You may or may not have used it in your own assignment writing, but chances are you may not be using it correctly. One of the reasons is that how to use etc. is not taught in English grammar and composition classes. But if you plan on using etcetera in academic writing, you will need to understand the rules. And that what this article is all about. So here goes. The term â€Å"et cetera† actually comes from Latin, and it means â€Å"so forth† or â€Å"and other similar things.† And using etcetera in academic writing is perfectly fine, as long as you do it right. How to Use Etc. in Lists of Things In this case, you will want to know how to use etc. at the end of a sentence and, as well, how do you use etc. in a sentence, when there is more that follows it. The important point in using etc. at the end of a list is that all things in the list must be related. Here are some examples of both situations: They can live in any body of fresh water – creeks, ponds, lakes, etc. That literature class covers fiction, non-fiction, short stories, novels, poetry, etc. We were asked to describe the emotion (anger, fear, joy, etc.) we felt when we viewed the photography. Bring any small items that may be of value - coins, stamps, jewelry, etc. to the appraiser on Thursday morning. Note that all of the items in the lists are related. Another important point in how to use etc. in a sentence is punctuation. Because it is an abbreviation, you must place a period at the end of it, no matter where it may appear. You don’t need a period if you spell it out, but be sure your spelling is correct. Excetera, etcetra, and exedra are common mis-spellings, so get it right. In the 4th example, note also that there was a dash before the list, rather than a term like â€Å"such as.† If you use â€Å"such as,† you do not need to use â€Å"etc.† because the meaning is already clear. Don’t Use Etc. More Than Once in a Sentence While using several â€Å"etc.’s† in speaking or in informal writing is often used for emphasis, using etc. in academic writing is far different. You can say to a friend, â€Å"I have to get to the grocery store, a doctor’s appointment  and my haircut appointment, write my essays before the deadline runs out, etc., etc., etc., before I can get back to home and start cleaning,† is common informal language. But in formal writing, only one â€Å"etc.† is â€Å"allowed.† Etc., How to Use When Referring to People This rule is simple. Never, never, never use etc. when referring to people. â€Å"We studied the works of Shakespeare, Milton, etc. in our English lit class,† is not acceptable. Either name them all or come up with some other term, like, â€Å"We studied all of the most famous authors in our English literature course.† Never Use â€Å"And† before â€Å"Etc.† The word â€Å"and† already implies what â€Å"etc.† means, and using it is just redundant. So, you can say, â€Å"The courses covered all of the major forms of government, including democracy, fascism, communism, monarchy, etc.,† or you can say, â€Å"The course covered all of the major forms of government, including democracy, fascism, communism, monarchy, and others.† Etc. How to Use Correct Punctuation This rule is quite simple. If you use â€Å"etc.† in the middle of a sentence, and it is not enclosed in parentheses, then you must use a comma after the abbreviation. If it is in parentheses in the middle of a sentence or at the end of a sentence, no comma is needed. Examples: Joe and I stuffed ourselves on pizza, beer, pork rinds, candy bars, etc., and we really felt it the next day. After finals were over, Joe and I stuffed ourselves on pizza, beer, pork rinds, candy bars, etc. After finals, Joe and I stuffed ourselves with every bit of junk we could find (pizza, beer, pork rinds, candy bars, etc.). Using Additional Punctuation after â€Å"Etc† Remember, â€Å"etc.† is an abbreviation, and abbreviations call for periods after them. This doesn’t mean that you don’t use any other punctuation after that period. Use all of the regular punctuation that you would if that â€Å"etc.† were just another word – question marks, exclamation points, semis: Are you going to bring the paper supplies, like plates, cups, napkins, etc.? I hate proofreading my essays, papers, etc.! We are not going to get anxious about these finals; we are not going to lose sleep, eat junk, etc.; and we are not going to go in with a defeatist attitude. In General You will not find the use of â€Å"etc.† rampant in academic writing. That is because scholarly research and writing is usually very specific and detailed and does not rely on the reader to â€Å"add† things on his own. Oh, yes, you can use it, certainly, in essays you may write for an English course. But use it sparingly in research works.

Close Reading about Poem Essay Example | Topics and Well Written Essays - 750 words - 1

Close Reading about Poem - Essay Example Besides, in an otherwise regular iambic pentameter, the poet also exploits a variation of accents to create a noticeable rhythm. For that matter the line 6 in the sonnet shows no distinctive alternation of the short syllables and the long syllables. The expressions â€Å"precious friends hid† and â€Å"dateless night† show a matching stress. The poet has also used assonance to add melody to the sonnet. For instance, the ‘e’ sounds in â€Å"When to the sessions† and â€Å"summons up remembrance† in the first two lines. The other particular thing that makes one appreciate the technical mastery of the poet is that he creates a sense of balance in the sonnet by linking enjambment in the 10th line of the sonnet with caesura in the 5th line. In Sonnet 29 one really feels sympathetic and sorry for the poet as he confesses that he lacked in the qualities required to be materialistically successful. However, the amazing thing is that the poem ends with the positive idea that sincere relationships can extend happiness and worth to an otherwise unsuccessful life. In the line 10 -12, the poet makes use of simile as he compares his depressed mental condition to a lark. This indeed enhances the dramatic element in the sonnet. Similarly the poet while saying â€Å"trouble def heaven† uses personification to convey his spiritual agony. Thereby, the Sonnet 29 is particularly rich in symbolism and allegorical implications. It is a well contrived sonnet primarily relying on a masterful use of sound patterns to achieve impact. The iambic pentameter in this particular sonnet throughout remains consistent. This consistent use of iambic pentameter when matched with an abrupt use of the literary device called ‘turn’ amply enhances the overall appeal of the poem. In this sonnet Shakespeare makes a skillful use of the tone and the diction to make