Kant Philosophy Essay Example | Topics and Well Written Essays - 250 words - 4

Kant Philosophy - Essay Example Obligations and inclinations arise from duty. Consoling a grieving friend arises from duty, which is part of moral judgments. It is the right thing to do in such a situation. Normative judgment specifies that consoling a person, as a specific course of action, is the rational course if they are grieving. Emotions motivate moral obligation because one empathizes through showing compassion. The moral law demands that one consoles a friend, but if goodwill does not motivate such an action, then the inclination may have selfish interests. Principle and reason shape human behavior, rather than the expected consequence or emotional feeling that triggers actions. For that reason, a person would see it right to console somebody because of principle, even if they feel no compassion or empathy for the victim. This means that conscious concerns regulate emotions and they serve an important role in the persons' moral life. Human dignity demands that one act in the similar way that they would like others to treat them. Even so, while the society cannot hold a person accountable for moral obligations or inclinations, they are accountable for their goodwill, because it is often under a person’s  control.

The Role of Peer Feedback in Improving EFL Writing Skills of Saudi Essay

The Role of Peer Feedback in Improving EFL Writing Skills of Saudi English Major Students - Essay Example The essay explains the role of peer feedback in helping them improve their EFL writing competencies. Following this, a section of the paper presents the concept of peer feedback in detail. Finally, the last section looks at the issue of collaborative learning, in order to provide a theoretical basis for the process of peer feedback to help better understand this type of approach. Many researchers have found a positive relation between students’ writing achievements and the provision of feedback. It is seen that feedback improves writing skills since it gives both students and teachers a picture of students' progress and improvement. It is also considered to be â€Å"a key element of the scaffolding provided by the teacher to build learner confidence and the literacy resources to participate in target communities†. This paper makes a conclusion that peer feedback as it was presented in this essay can be a very beneficial collaborative activity in EFL writing sessions. Unfortunately, this kind of feedback is novel in many non-Western teaching contexts such as Saudi Arabia where teacher-feedback based classes are still dominant. The education system in Saudi Arabia is in the traditional style where it is loaded by rules, and is bound by a certain structure. Saudi students are taught writing by structured written exercises and traditional drills. Students’ writing is most often controlled and guided with model writings provided by teachers rather than allowing them to write freely. However, this situation could be changed with proper awareness of the educational problems and with appropriate writing instructions such as applying cooperative learning and peer feedback to make students better writers.

Vapor Compression Refrigeration Cycle Engineering Essay

Vapor Compression Refrigeration Cycle Engineering Essay A compressor is a mechanical device that used increases the pressure of a compressible fluid. The inlet pressure level can be any value from a deep vacuum to a high positive pressure. The discharge pressure can range from sub-atmospheric levels to high values in tens of thousands of pounds per square inch. The inlet and outlet pressure are related, corresponding with the type of compressor ant its configuration. Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. The fluid can be any compressible fluid, either gas or vapor, and can have a wide molecular weight range, that are from 2 for hydrogen to 352 for uranium hexafluoride. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are relatively incompressible, so the main action of a pump is to pressurize and transport liquids. Applications of compressed gas vary from consumer products, such as the home refrigerator, to large complex p etrochemical plant installations. A vapor compression refrigeration system uses a refrigerant sealed in an airtight and leak proof mechanism. The refrigerant is circulated through the system and it undergoes a no of changes in its state while passing through various components of the system. Each such change in the state of vapor is called a process. The process of repetition of a similar order of operation is called a cycle. The compression cycle is given this name because it is the compression of the refrigerant by the compressor which permits transfer of heat energy. The refrigerant absorbs that from one place and releases it to another place. In other words the compressor is used to put the heat laden refrigerant vapor in such a condition that it may dispute the heat it absorbed at low pressure from the refrigerated space, to an easily available cooling medium. Oil refineries, petrochemical and chemical processing plants, and natural gas processing plants are among the many types of industrial plants that often u tilize large vapor-compression refrigeration systems. 2.1 Description of Vapor Compression System Most of the modern refrigerators work on this cycle. In its simplest form there are four fundamental operations require to complete one cycle. Compressor The low pressure vapor in dry state is drawn from the evaporator during the suction stroke of the compressor. During compression stroke the pressure and temperature increase until vapor temperature is greater than the temperature of condenser cooling medium. Condenser When the high pressure refrigerant vapor enters the condenser heat flows from condenser to cooling medium thus allowing the vaporized refrigerant to return to liquid state. Expansion Valve After condenser the liquid refrigerant is stored in the liquid receiver until needed. From the receiver it passes through an expansion valve where the pressure is reduced sufficiently to allow the vaporization of liquid a low temperature of about -10C. Evaporator The low pressure refrigerant vapor after expansion in the expansion valve enters the evaporator or refrigerated space where a considerable amount of heat is absorbed by it and refrigeration is furnished. The schematic diagram of the arrangement is as shown in Figure 2.1 below. The low temperature, low pressure vapor at state B is compressed by a compressor to high temperature and pressure vapor at state C. This vapor is condensed into high pressure vapor at state D in the condenser and then passes through the expansion valve. Here, the vapor is throttled down to a low pressure liquid and passed on to an evaporator, where it absorbs heat from the surroundings from the circulating fluid (being refrigerated) and vaporizes into low pressure vapor at state B. The cycle then repeats. B D C A Figure 2.1: Simple Vapor Compression System. The exchange of energy is as follows: Compressor requires work, w. The work is supplied to the system from the surroundings During condensation, heat Q1 the equivalent of latent heat of condensation etc, is lost from the refrigerator. During evaporation, heat Q2 equivalent to latent heat of vaporization is absorbed by the refrigerant. There is no exchange of heat during throttling process through the expansion valve as this process occurs at constant enthalpy. 2.2 Simple Vapor Compression Cycle Figure 2.2 below shows the simple vapor compression cycle: Figure 2.2: Simple Vapor Compression Cycle Process 1-2: The refrigerant as a mixture of liquid and vapour corresponding to state point 1 enters the compressor where isentropic compression takes place. The compression process increases the temperature of refrigerant from lower limit T2 to the upper limit Tl. Work is supplied to the system and after compression, the vapour is wet or saturated but not superheated. Process 2-3: The refrigerant in the form of vapour enters the condenser at state 2 and heat is rejected at constant pressure and temperature. At exit from the condenser, the refrigerant becomes saturated liquid at state point 3. Process 3-4: The refrigerant at state point 3 enters the expansion cylinder expands isentropic ally and its temperature drops to lower temperature T2 at the end of the expansion process. Work is obtained during the expansion process. Process 4-1: The liquid refrigerant at point 4 enters the evaporator and extracts heat at constant pressure and temperature from the space or substance being cooled and thus produces refrigerating effect. 2.3 Refrigeration Refrigeration may be defined as lowering the temperature of an enclosed space by removing heat from that space and transferring it elsewhere. A device that performs this function may also be called a heat pump. Freon is a trade name for a family of haloalkane refrigerants manufactured by DuPont and other companies. These refrigerants were commonly used due to their superior stability and safety properties: they were not flammable nor obviously toxic as were the fluids they replaced, such as sulfur dioxide. Newer refrigerants that have reduced ozone depletion effect include HCFCs (R-22, used in most homes today) and HFCs (R-134a, used in most cars) have replaced most CFC use. HCFCs in turn are being phased out under the Montreal Protocol and replaced by hydrofluorocarbons (HFCs), such as R-410A, which lack chlorine. However, CFCs, HCFCs, and HFCs all have large global warming potential. Newer refrigerants are currently the subject of research, such as supercritical carbon dioxide, known as R-744.[4] These have similar efficiencies compared to existing CFC and HFC based compounds, and have many orders of magnitude lower global warming potential. 3.0 TYPES OF COMPRESSORS 3.1 Centrifugal Compressor Centrifugal compressors use a rotating disk or impeller in a shaped housing to force the gas to the rim of the impeller, increasing the velocity of the gas. A diffuser (divergent duct) section converts the velocity energy to pressure energy. They are primarily used for continuous, stationary service in industries such as oil refineries, chemical and petrochemical plants and natural gas processing plants. Their application can be from 100ÂÂ  horsepower (75ÂÂ  kW) to thousands of horsepower. With multiple staging, they can achieve extremely high output pressures greater than 10,000ÂÂ  psi (69ÂÂ  MPa). Many large snowmaking operations (like ski resorts) use this type of compressor. They are also used in internal combustion engines as superchargers and turbochargers. Centrifugal compressors are used in small gas turbine engines or as the final compression stage of medium sized gas turbines. 3.2 Axial Flow Compressor Axial-flow compressors are dynamic rotating compressors that use arrays of fan-like airfoils to progressively compress the working fluid. They are used where there is a requirement for a high flow rate or a compact design. The arrays of airfoils are set in rows, usually as pairs: one rotating and one stationary. The rotating airfoils, also known as blades or rotors, accelerate the fluid. The stationary airfoils, also known as stators or vanes, decelerate and redirect the flow direction of the fluid, preparing it for the rotor blades of the next stage. Axial compressors are almost always multi-staged, with the cross-sectional area of the gas passage diminishing along the compressor to maintain an optimum axial Mach number. Beyond about 5 stages or a 4:1 design pressure ratio, variable geometry is normally used to improve operation.Axial compressors can have high efficiencies; around 90% polytropic at their design conditions. However, they are relatively expensive, requiring a large number of components, tight tolerances and high quality materials. Axial-flow compressors can be found in medium to large gas turbine engines, in natural gas pumping stations, and within certain chemical plants. 4.0 APPLICATION OF COMPRESSORS Gas compressors are used in various applications where either higher pressures or lower volumes of gas are needed: Pipeline transport of purified natural gas To move the gas from the production site to the consumer, or the transportation of goods through a pipe. Most commonly, liquid and gases are sent, but pneumatic tubes that transport solid capsules using compressed air have also been used. Often, the compressor in this application is driven by a gas turbine which is fueled by gas bled from the pipeline. Thus, no external power source is necessary. Plants and refineries Petroleum refineries, natural gas processing plants, petrochemical and chemical plants, and similar large industrial plants for compressing intermediate and end product gases. Refrigeration and air conditioner equipment To move heat from one place to another in refrigerant cycles: see Vapor-compression refrigeration. Gas turbine systems To compress the intake combustion air Commercial industry Storing purified or manufactured gases in a small volume, high pressure cylinders for medical, welding and other uses. Cylinder SCUBA diving, hyperbaric oxygen therapy and other life support devices to store breathing gas in a small volume such as in diving cylinders. Many various industrial, manufacturing and building processes to power all types of pneumatic tools.

sumthin on hitler :: essays research papers

Adolf Hitler was an enigma to many people. The mysterious, vibrant man who believed above all in his supreme confidence led Germany down one of the 20th century's darkest paths. Indeed, any understanding of the actions taken by Germany in the 1930s and 40s must be based upon concise knowledge of Hitler as the country's leader. The following is a compendium directed at examining closely Adolf Hitler the man who became Adolf Hitler the myth. Hitler entered office in the wake of some of the happiest years of his life. During the years 1926-29 he had purchased a home in the Bavarian mountains (1927) and his lazy days were filled with painting and daydreaming. He was quietly laying out of the public eye before coming to power (ironically in a democratic fashion) in 1933. When Hitler took office he immediately began to make his mark. He was a man who believed himself to be a supreme judge in all areas, and this was exemplified when he appointed committees to oversee every facet of social life (theater, propaganda, education, dress, etc...). However, whenever Hitler disagreed with any decision made by a committee, he would automatically overrule in his favor. He believed in his hardness and his brutality, and above all his confidence and ultimate inevitable success. As his regime began to grow stronger, so did this boundless confidence. Hitler's greatness was something that he was aware of and wanted to make the public aware of as well. The best way he exuded himself to the public was through his speeches. He seemed to be a man possessed to the public, a mystifying presence in public who began to sway the will of the people. Here is where the mythical man was born. He was the tireless public speaker who dared to brave the law and uncover the true state of affairs for the people. He was the man who's heart was in the cause and could arouse the emotions of the people and channel them to the nationalism they wanted. Through his endless public addresses and tireless effort, he became a man who the people saw as their champion. He embraced this feeling and became a leader of near biblical proportions in Germany. But who was this man underneath the growing myth? What was he like? The man himself is a study all his own. He was a very secretive man about his personal life which

Austin V. Berryman United States Supreme Court of Appeal Essay

Citation: Austin V. Berryman United States Supreme Court of Appeal, Fourth Circuit, 1989. Facts: Barbra Austin is challenging the Virginia Employment Commission for unemployment compensation benefits, which she chose to quit her job out of religious beliefs to fallow her spouse. Issue: She is claimed to be denied of her unemployment compensation benefits because she quilted due to her religious belief and distance from her new home to her workplace. Decision: The decision was that Austin was denied of her unemployment compensation benefits not because of her religion or how far she lived from her workplace. Reason: Austin’s religious belief does not require her to be kept her away from work but what really is the matter is that the distances from home to work. In the state of Virginia, its laws stated that moving 150 miles away from work does not prove that she cannot work at that distance but she quitted with that reason. Questions on the Case Analysis 1. The plaintiff was Barbra Austin and the defendant was the Virginia Employment Commission. 2. Mainly because Austin home was too far away from her work place but she also stated that it was her religious beliefs to move with her spouses if they move. 3. She was refused of her unemployment benefits because this was nothing to do with her religion but rather her issue with the traveling distance from home to work, which can be solved easily. 4. No, since this has no known issue that deals with religion, the state did not violate her rights. 5. The court’s conclusion was that it was her responsibility to manage the possible way to get to her workplace to from home regardless how far in the state of Virginia.

Hydraulic Machines

30 CHAPTER 5 TURBINES 5. 1 Introduction Hydraulic turbines are the machines which use the energy of water and convert it to mechanical energy. The mechanical energy developed by a turbine is used in running an electric generator which is directly coupled to the shaft of the turbine. The electric generator thus develops electric power, which is known as hydro-electric power. 5. 2 Elements of Hydraulic Power Plants Fig. 5. 1 General Layout of a Hydraulic Power Plant 31 Fig. 5. 1 shows a general layout of hydraulic power plant, in which an artificial storage reservoir formed by constructing a dam has been shown. 5. 3General Classification of Turbines Turbines are hydraulic machines that convert energy into rotating mechanical energy which in turn generators to produce electrical energy. Originally developed from the water wheels, hydraulic turbines are the prime mortars of importance in modern water power development. According to their hydraulic action, turbines are broadly divided int o two classes. (1) Impulse Turbine: Impulse turbines are more efficient for high heads. At the inlet to the turbine runner, pressure head can be completely converted into kinetic head in the form of a jet of water issuing from one or more nozzles.The free jet will be at atmospheric pressure before as well as after striking the vanes. The turbines are regulated by nozzles which may be a simple straight flow type or a deflector type. The impulse turbines are commonly represented by Pelton Wheels. Turgo turbine is also an impulse turbine but with different buckets, when compared with pelton. Turgo and cross flow turbines are relatively new developments in this class. The main advantages of these turbines are: †¢ They can be easily adopted to power variation with almost constant efficiency. †¢The penstock overpressure and the runner overspeed control are easier. †¢ The turbine enables an easier maintenance. †¢ Due to the jet the manufacturer of these turbines impose a better solid particle control, conducting, consequently, to a lower abrasion effect. (2) Reaction Turbine: A turbine can be made to rotate under the action of water flowing under pressure through the runner. In such turbines the penstocks, the inlet passage to the runner, passage between the runner vanes, all form a continuous passage for the flow under a pressure which continuously decreases from inlet to outlet.The turbine runner directly converts both kinetic energy as well as the pressure energy into mechanical energy. Reaction turbines are represented in modern practice by two principal types: the Francis turbine where the flow is directed radial to the runner axis and the Propeller type 32 where the flow is axial to the runner axis. Propeller turbines may be fixed blade or adjustable blade types. Kaplan turbine has adjustable blades. The main advantages of these turbines are: †¢ It needs lesser installation space. †¢ It provides a greater net head and a better prot ection against downstream high flood levels. It can have greater runner speed. †¢ It can attain greater efficiencies for high power values. In order to distinguish different turbines, the hydraulically salient features like pressure, head, flow direction and magnitude, speed and power etc. The general classification of hydraulic turbines is illustrated in Fig. 5. 2. Hydraulic Turbines Impulse Turbines Pelton Turgo Reaction Turbines Cross-Flow Fixed -Blade Propeller Kaplan Francis Tubular Deriaz Bulb Fig. 5. 2 General Classification of Turbines 5. 4 Number of Units It is normally cost effective to have a minimum number of units at a given small ydropower installation. Multiple units may, however, be necessary from the operational point of view so that even one unit breaks down or is in the routine maintenance, the power generation can be achieved to a certain extent. The efficiency curves of turbines show that the 33 efficiency of power generation from hydraulic turbines conside rably decreases at low flow ratios or power ratios. In multiple units, it is possible to maintain the higher efficiency even in low flows and the low loads by running a certain number of the units at a time depending upon the available discharge and the load demand.Multiple units thus, make the most effective use of water where the flow as well as the load variations are significant. 5. 5 Limits of Use of Turbine Types The selection of best turbines for any particular small hydropower site depends on the site characteristics, the dominant beings the head and the available flow. There are some limits on the range of these parameters in the selection of turbines. Each turbine type is best suited to a certain range of pressure head and the flow rate. For instance, Pelton wheels operate with low flows discharged under great pressures where as Propeller turbines are effective in high flows under low heads.Francis turbines fall in the medium category covering a wide range of different hea ds and discharges. The common practice of SHP systems is to develop standard unit sizes of equipment that will operate over a range of heads and flows. Either charts or nomographs are used to select appropriate units for site specific application. One such chart showing the head-flow range of normal SHP schemes applicable to each type of turbine is given in Fig5. 3. The graph also indicates the approximate power generation for each combination of the head and the discharge applicable to SHP schemes. Fig. . 3 Head-Flow Ranges for Different Turbines 34 5. 6 Pelton Wheel Pelton wheel is well suited for operating under high heads. A pelton turbine has one or more nozzles discharging jets of water which strike a series of buckets mounted on the periphery of a circular disc. The runner consists of a circular disc with a number of buckets evenly spaced round its periphery. The buckets have a shape of a double semi-ellipsoidal cups. The pelton bucket is designed to deflect the jet back thro ugh 165 ° which is the maximum angle possible without the return jet interfering with the next bucket.Fig. 5. 4 Pelton bucket General arrangement of a pelton wheel is shown in the Fig. 5. 5. For SHP schemes, Pelton wheels are easier to fabricate and are relatively cheaper. The turbines are in general, not subjected to the cavitation effect. The turbines have access to working parts so that the maintenance or repairs can be effected in a shorter time. Fig. 5. 5 General Arrangement of a Pelton Wheel 35 Traditionally, micro hydro pelton wheels were always single jet because of the complexity and the cost of flow control governing of more than one jet.Advantages of multi-jet: -Higher rotational speed -Smaller runner -Less chance of blockage Disadvantages of multi-jet: -Possibility of jet interference on incorrectly designed systems -Complexity of manifolds 5. 7 Francis Turbine Francis turbine is a mixed flow type, in which water enters the runner radially at its outer periphery and le aves axially at its center. Fig. 5. 6 illustrates the Francis turbine. The runner blades are profiled in a complex manner and the casing is scrolled to distribute water around the entire perimeter of the runner.The water from the penstock enters a scroll case which completely surrounds the runner. The purpose of the scroll case is to provide an even distribution of water around the circumference of the turbine runner, maintaining an approximately constant velocity for the water so distributed. The function of guide vane is to regulate the quantity of water supplied to the runner and to direct water on to the runner at an angle appropriate design. A draft tube is a pipe or passage of gradually increasing cross sectional area which connects the runner exit to the tail race. Fig. 5. 6 Francis Turbine 36 . 8 Kaplan Turbine It is an axial flow turbine which is suitable for relatively low heads. From Fig. 5. 7, it will be seen that the main components of Kaplan turbine such as scroll casi ng, guide vanes, and the draft tube are similar to those of a Francis turbine. Fig. 5. 7 5. 9 Kaplan Turbine Specific Speed The specific speed of any turbine is the speed in r. p. m of a turbine geometrically similar to the actual turbine but of such a size that under corresponding conditions it will develop 1 metric horsepower when working under unit head. Ns = NP H5/ 4 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(5. 1) where Ns = specific speedP = power in HP 5. 10 Characteristic Curves The turbines are generally designed to work at particular values of H,Q,P,N and ? o which are known as the designed conditions. It is essential to determine exact behaviour of the turbines under the varying conditions by carrying out tests either on the actual turbines or on their small scale models. The results of these tests are usually graphically represented and the resulting curves are known as characteristic curves. 37 -constant head characteristic curves -constant speed characteristic curves -constan t efficiency characteristic curvesIn order to obtain constant head characteristics curves the tests are performed on the turbine by maintaining a constant head and a constant gate opening and the speed is varied by changing the load on the turbine. A series of values of N are thus obtained and corresponding to each value of N, discharge Q and the output power P are measured. A series of such tests are performed by varying the gate opening, the head being maintained constant at the previous value. From the data of the tests the values of Qu, Pu, nu and ? o are computed for each gate opening. Then with Nu as abscissa the values ofQu, Pu and ? o for each gate opening are plotted. The curves thus obtained for pelton wheel and the reaction turbines for four different gate openings are shown in Fig. 5. 8. Fig. 5. 8 Constant head characteristics for Pelton wheel and reaction turbines 38 5. 11 Cavitation in turbines When the pressure in any part of the turbine reaches the vapour pressure of the flowing water, it boils and small bubbles of vapour form in large numbers. These bubbles are carried along by the flow, and on reaching the high pressure zones these bubbles suddenly collapse as the vapour condenses to liquid again.The alternate formation and collapse of vapour bubbles may cause severe damage to the surface which ultimately fails to fatigue and the surface becomes badly scored and pitted. This phenomenon is known as cavitation. In order to determine whether cavitation will occur in any portion of the turbine, D. Thomas has developed a dimensionless parameter called Thomas'cavitation factor ? which is expressed as ?= Ha ? Hv ? Hs H †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(5. 2) where Ha = atmospheric pressure head Hv = vapour pressure head Hs = suction pressure head For Francis turbines: Critical cavitation factor ? c = 0. 625 (Ns/444)2 †¦Ã¢â‚¬ ¦.. (5. 3) For Propeller turbines: ? c = 0. 28 + [ Example 5. 1 1 Ns 3 ( )] 7. 5 444 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. (5. 4) Est imate the maximum height of straight conical draft tube of a 18000 h. p. Francis turbine running at 150 r. p. m under a net head of 27 m. The turbine is installed at a station where the effective atmospheric pressure is 10. 6 m of water. The draft tube must sink at least 0. 77 m below the tail race. Ns = NP H5/ 4 = 327 39 ?c = 0. 625 (Ns/444)2 = 0. 339 Cavitation factor ? = Ha -Hv -Hs H Ha -Hv = 10. 6 m, H =27 m 0. 339 = 10. 6 -Hs 27 Hs = 1. 45 m Max length of the draft tube = 1. 45 + 0. 7 = 2. 22 m 5. 12 Governing of Turbines All the modern turbines are directly coupled to the electric generators. The generators are always required to run at constant speed irrespective of the variations in the load. This constant speed N of the generator is given by the expression N= 60 f p †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. (5. 5) where f = frequency (usually 50) p = numbers of pairs of poles 5. 13 Water Hammer A gate or valve at the end of the penstock pipe controls the discharge to the turbine. As s oon as this governor regulated gate opening is altered, the pipe flow has to be adjusted to the new magnitude of flow.In doing so, there are rapid pressure oscillations in the pipe, often accompanied by a hammering like sound. Hence this phenomenon is called as water hammer. 5. 14 Jet Speed The velocity of flow of the jet depends upon the total net head H at the base of the nozzle and is given by the nozzle equation: v = C v ? 2gH where the discharge coefficient velocity of the nozzle is taken as 0. 95. †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(5. 6) 40 5. 15 Bucket speed V= ? DN 60 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(5. 7) The bucket speed should be half of the jet speed. In practice, losses in the turbine cause the maximum efficiency to occur at slightly less than a half, typically 0. 46. V =0. 6 v 5. 16 Design of Pelton Wheel Runner diameter: Runner diameter can be found out from the rpm equation. D= 38 ? H N †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. (5. 8) where N = runner speed(rpm) H = net head Nozzle diameter: The nozzle diameter is given by the nozzle equation: d = 0. 54 ? Q 0. 5 1 ? 0. 25 H n jet †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. (5. 9) Jet ratio: Jet ratio D/d is a size parameter for the turbine. It has a value in a range of 10 to 24. For the high efficiency Pelton wheel design, the ratio of the runner diameter to the nozzle should be more than 9. Number of buckets: The number of buckets required for the efficient operation of the Pelton turbine is calculated as:N buc = 0. 5 ? D + 15 d †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. (5. 10) In practice, the selection and the detail design of the turbine units are carried out by the manufactures based on the model performances. 41 Example 5. 2 Powerhouse is equipped with a vertical shaft pelton turbine. The generator is provided with 6 pairs of poles. Design discharge is 1. 4 m3/s and net head is 425 m. The turbine will provide 6500 hp. Take coefficient of nozzle as 0. 95. Determine (a) the specific speed (b) velocity of jet (c) jet diameter (d) pitch circle diameter of the wheel (e) number of buckets (a) N= 60 f p = 60 x 50/6 = 500 rpmNs = = NP H5/ 4 500 6500 4255 / 4 = 20. 9 Use single jet pelton turbine (b) velocity of jet v = C v ? 2gH = 0. 95 ? 2Ãâ€"9. 81Ãâ€"425 = 86. 75 m/s (c) jet diameter d = 0. 54 ? = 0. 54 ? Q 0. 5 1 ? 0. 25 H n jet 1. 4 0. 5 425 0. 25 ? = 0. 14 m =14 cm 1 1 42 (d) pitch circle diameter D= 38 ? H N = 1. 57 m (e) Number of buckets N buc = 0. 5 ? N buc = 0. 5 ? D + 15 d 1. 57 + 15 0. 14 = 20. 6 = 21 5. 17 Work done of Pelton Wheel In turbines, the water flows on to the runner, which itself is rotating with a certain speed. The water flows over the runner and leaves the runner at its outlet point.We can speak of absolute velocity of water before it flows in the runner, the relative velocity of water w. r. t the runner and again the absolute velocity of water after it has left the runner. In order to ascertain the relationship between these velocities, the velocity vector diagram prove to be very useful. Fig. 5. 9 shows the velocity triangles at the tips of the bucket of a pelton wheel. At the outlet tip velocity triangles are different depending upon the magnitude of u corresponding to which it is slow, medium or fast runner. Inlet velocity diagram VVri Vai =Vwi 43 Outlet velocity diagram V Vwo ? ? Vfo Vro Vao Fig. 5. 9 Velocity triangles V = bucket velocity Vai = absolute velocity of jet at inlet tip Vai = Cv 2 gH1 Vao = absolute velocity of jet at outlet tip Vri = relative velocity of jet at inlet = Vai-V Vro = relative velocity of jet at outlet = k. Vri Vwi = velocity of whirl at inlet =Vai Vwo = velocity of whirl at outlet = V-VroCos ? Vfo = velocity of flow at outlet Mass/sec m =? Q =? a Vai=? ?/4 d2 Vai †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(5. 11) Workdone on the bucket/sec (power developed by turbine) P = m (Vwi -Vwo) V †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(5. 12)Maximum hydraulic efficiency ? h max = 1 (1 + kCos? ) 2 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(5. 13) The hydraulic efficiency is maximum when the bucket speed is equal to half of the velocity of jet. 44 Example 5. 3 The head available at entrance to the nozzle supplying a pelton wheel is 300 m and the coefficient of velocity for the nozzle is 0. 98. The wheel diameter is 1. 8 m and the nozzle diameter is 125 mm. The buckets deflect the jet through 165 °. Assuming the relative velocity of the jet is reduced by 16%, calculate the theoretical speed in rev per min for the maximum hydraulic efficiency.What is the hydraulic efficiency when running at this speed, and what is the power developed? Deflection angle =165 ° = (180- ? ) ? = 15 ° k = 0. 84 hf hn H'=Vai2/2g H For max hydraulic efficiency V/Vai =0. 5 Vai = Cvv2gH1 = 75 m/s V =Vai/2 = 37. 5 m/s V =? DN/60 N =60V/? D = 398 rpm ?hmax = 1/2 (1+ k Cos ? ) = 90. 55 % mass/sec = m = ? Q = ? ?/4 d2 Vai = 920 kg/sec H1 45 Inlet diagram: V Vri From velocity diagram Vwi = Vai =75 m/s Vri = Vai- V =37. 5 m/s Vwi = Vai Outlet diagram: Vwo = V -Vro Cos ? V = V – k Vri Cos ? Vwo Vro Power = m V ( Vwi -Vwo) = 234600 Watts Vao =7 m/s 46 CHAPTER 6CENTRIFUGAL PUMP 6. 1 Introduction Centrifugal pumps are classified as rotodynamic type of pumps in which dynamic pressure is developed which enables the lifting of liquids from a lower to a higher level. The basic principle on which a centrifugal works is that when a certain mass of liquid is made to rotate by an external force, it is thrown away from the central axis of rotation and a centrifugal head is impressed which enable it to rise to a higher level. Now, if more liquid is constantly made available at the centre of rotation, a continuous supply of liquid at a higher level may be ensured.Since in these pumps the lifting of the liquid is due to centrifugal action, these pumps are called ‘centrifugal pumps'. 6. 2 Advantages of centrifugal pumps over reciprocating pumps The main advantage of a centrifugal pump is that its discharging capacity is very much greater than a reciprocating pump which can handle relatively small quantity of liquid only. A centrifugal pump can be operated at very high speeds without any danger of separation and cavitation . The maintenance cost of a centrifugal pump is low and only periodical check up is sufficient .But for a reciprocating pump the maintenance cost is high because the parts such as valves etc. , may need frequent replacement. 6. 3 Component Parts of a Centrifugal Pump The main component parts of a centrifugal pump are: -impeller -casing -suction pipe -delivery pipe 47 Fig. 6. 1 Component part of a centrifugal pump 6. 4 Workdone by the Impeller The expression of the workdone by the impeller of a centrifugal pump on the liquid flowing through it may be derived in the same way as for a turbine. The liquid enters the impeller at its centre and leaves at its periphery. Fig. 6. shows a portion of the impeller of a centrifugal pump with one vane and the velocity triangles at the inlet and outlet tips of the vane. V is absolute velocity of liquid, u is tangential velocity of th e impeller, Vr is relative velocity of liquid, Vf is velocity of flow of liquid, and Vw is velocity of whirl of the liquid at the entrance to the impeller. Similarly V1,u1,Vr1,Vf1 and Vw1 represent their counterparts at the exit point of the impeller. 48 Fig. 6. 2 Velocity triangles for an impeller vane ? = the impeller vane angle at the entrance ? = the impeller vane angle at the outlet = the angle between the directions of the absolute velocity of entering liquid and the peripheral velocity of the impeller at the entrance ? = the angle between the absolute velocity of leaving liquid and the peripheral velocity of the impeller at the exit point Work done per second by the impeller on the liquid may be written as Work done = W ( Vw1 u1 – Vw u) ————-(6. 1) g where W kg of liquid per second passes through the impeller. Since the liquid enters the impeller radially ? = 90 and hence Vw = 0. Thus equation (6. 1) becomes Work done = W (Vw1u1) —â⠂¬â€Ã¢â‚¬â€Ã¢â‚¬â€-(6. ) g 6. 5 Head of a Pump The head of a centrifugal pump may be expressed in the following two ways: (a) Static head (b) Manometric head (or total head or gross head) 49 Fig. 6. 3 Head on a centrifugal pump (a) Static Head Static head is the vertical distance between the liquid surfaces in the pump and the tank to which the liquid is delivered by the pump. Static head (or lift) Hs = hs + hd where hs = static suction lift hd = static delivery lift †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. (6. 3) 50 (b) Manometric Head Manometric head is the total head that must be produced by the pump to satisfy external requirements.If there are no energy losses in the impeller and the casing of the pump, then the manometric head Hm will be equal to the energy given to the liquid by the V ? 1u1 g impeller, i. e Hm = . But if losses occur in the pump then V ? 1u1 ? losses of head in the pump g †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. (6. 4) Applying Bernoulli’s equation between the points, O at the liqui d surface in the pump and 1 in the suction pipe just at the inlet to the pump (i. e. , at the centre line of the pump), the following expression is obtained if the liquid surface in the sump is taken as datum. 0= p s Vs2 + + hs + h f s ? 2g ps Vs2 ? [ + hs + h fs ] 2g ? †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. (6. 5) where ps is the pressure at point l ; Vs is the velocity of flow in the suction pipe ; hs is the suction lift and hfs is the head loss in the suction pipe which includes the head loss due to friction and the other minor losses. It may however be pointed out that if the pump is situated below the level of the liquid surface in the sump, hs will be negative. Equation (6. 5) indicates that at the inlet to the pump there is always a suction or vacuum pressure developed which will be recorded by the vacuum gauge provided at this point as shown in Fig. . 3. The head expressed by equation (6. 5) is called the suction head of the pump. Also, applying Bernoulli’s equation between points 1 and 2, which is just at the outlet of the impeller and is assumed to be at the same level as point 1, then since the impeller imparts a head equal to (Vw1u1/g) to the liquid the following expression is obtained: p s V s2 V? 1u1 p 2 V12 + + = + + hLi ? 2g g ? 2g †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. (6. 6) where p2 is the pressure and V1 is the absolute velocity of the liquid leaving the impeller and hLi is the loss of head in the impeller. 51 6. Specific Speed of Centrifugal Pumps In order to compare the performance of different pumps, it is necessary to have some term which will be common to all centrifugal pumps. The term used for this purpose is the specific speed. The specific speed of a centrifugal pump is the speed at which the specific pump must run to deliver unit quantity against unit head, the efficiency being the same as the actual pump. Ns = NQ H 3/ 4 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦(6. 7) where Ns= specific speed N = rotational speed(rpm) H = total head 6. 7 Performance of Pumps- Charact eristic CurvesA pump is usually designed for one speed, flow rate and head in actual practice, the operation may be at some other condition of head on flow rate, and for the changed conditions, the behaviour of the pump may be quite different. Therefore, in order to predict the behaviour and performance of a pump under varying conditions, tests are performed and the results of the tests are plotted. The curves thus obtained are known as the characteristic curves of the pump. The following three types of characteristic curves are usually prepared for the centrifugal pumps : a) Main and operating characteristics. (b) Constant efficiency or Muschel curves . (c) Constant head and constant discharge curves. Main and Operating Characteristics In order to obtain the main characteristic curves of a pump it is operated at different speeds. For each speed the rate of flow Q is varied by means of a delivery valve and for the different values of Q the corresponding values of manometric head Hm, shaft H. P. , P , and overall efficiency ? are measured or calculated. The same operation is repeated for different speeds of the pump. Then Q v/s Hm ; Q v/s P and Q v/s ? urves for different speeds are plotted, so that three sets of curves, as shown in Fig. 6. 4 are obtained, which represent the 52 main characteristics of a pump. The main characteristics are useful in indicating the performance of a pump at different speeds. During operation a pump is normally required to run at a constant speed, which is its designed speed, (same as the speed of the driving motor). As such that particular set of main characteristics which corresponds to the designed speed is mostly used in the operations of a pump and is, therefore, known as the operating characteristics.A typical set of such characteristics of a pump is shown in Fig. 6. 5 Fig. 6. 4 Main characteristics of a centrifugal pump Fig. 6. 5 Operating characteristic curves of a centrifugal pump 53 6. 8 Parallel or Series Operation of Pu mps Pumps in series Centrifugal pumps generate a relatively low head delivering a fairly high rate of discharge. Normally a pump with a single impeller can be used to deliver the required discharge against a maximum head of about 100 m. But if the liquid is required to be delivered against a still larger head then it can be done by using two or more pumps in series. Fig. 6. 6 Three stage centrifugal pumpIf the required head is more than that can be provided by one pump, the pumps are connected in series. The same discharge passes through both pumps but the head developed by one pump add the other. The total head developed is obtained by adding together the value of the head of each pump corresponding to the relevant discharge. Pumps in Parallel The multi-stage pumps or the pumps in series as described earlier are employed for delivering a relatively small quantity of liquid against very high heads. However, when a large quantity of liquid is required to be pumped against a relativel y small head, then it may 4 not be possible for a single pump to deliver the required discharge. In such cases two or more pumps are used which are so arranged that each of these pumps working separately lift the liquid from a common sump and deliver it to a common collecting pipe through which it is carried to the required height Fig. 6. 7. Since in this case each of the pumps deliver the liquid against the same head, the arrangement is known as pumps in parallel. If Q1, Q2, Q3†¦.. , Qn are the discharging capacities of n pumps arranged in parallel then the total discharge delivered by these pumps will beQt = (Q1+Q2+Q3+†¦Ã¢â‚¬ ¦+Qn) †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. (6. 8) If the discharging capacity of all the n pumps is same, equal to Q , then the total discharge delivered by these pumps will be Qt = nQ Fig. 6. 7 Two centrifugal pumps arranged in parallel 55 A centrifugal pump, having four stages in parallel, delivers 11m3/min of Example 6. 1 liquid against a head of 24. 7m , the diameter of the impeller being 225mm and the speed 1700 rpm. A pump is to be made up with a number of identical stages in series, of similar constriction to those in the first pump, to run at 1250 rpm, and to deliver 14. 5 m3/min, against a head of 248m.Find the number of stages required for the second pump. 1st Pump 2nd Pump Q = 11m3/min Q = 14. 5m3/min H = 24. 7 m H = 248 m N = 1700 rpm N =1250 rpm D = 225 mm Specific speed N s = NQ H 3/ 4 Q for one pump = 11/4 = 2. 75 m3/min Ns = 1700 2. 75 24. 7 3 / 4 = 254 For 2nd pump, with identical stages in series i. e multi-stage pump, if each stage is similar to those of each stage is similar to those of the first pump. The specific speed of each stage Ns = 254 Ns = 254 = NQ H 3/ 4 1250 14. 5 H 3/ 4 H = 49. 64 m Total head required = 248 m No of stages required = 248/49. 64 = 5 stages 56 CHAPTER 7DIMENSIONAL ANALYSIS, HYDRAULIC SIMILITUDE AND MODEL INVESTIGATION 7. 1 Dimensional Analysis Dimensional analysis is a mathematical method of obtaining the equations, changing units, determining a convenient arrangement of variable of a physical relation. In an equation expressing a physical relationship between quantities, absolute numerical and dimensional equality must exit. In general, all such physical relationships can be reduced to the fundamental quantities of mass M, length L and time T. It is a based on the assumption that the phenomenon can be expressed by a dimensionally homogeneous equation, with certain variable.The dimensional analysis is widely used in research work for developing design criteria and also for conducting model tests. 7. 2 Dimensions and Units All physical quantities are measured by comparison. This comparison is always made with respect to some arbitrarily fixed value for each independent quantity, called dimension(e. g. , length, mass, time, etc. ). Since there is no direct relationship between these dimensions, they are called fundamental dimensions. Some other quantities such as area , volume, velocity, force etc. can not be expressed in terms of fundamental dimensions and thus may be alled derived dimensions. There are two systems for fundamental dimensions namely FLT (i. e force, length, time) and MLT (i. e. , mass, length, time). One common system employed in dimensional analysis is the M,L,T system. Table is a listing of some of the quantities used in fluid flow, together with their symbols and dimensions. 57 Quantity Symbol Dimensional Form Length l L Time t T Mass m M Velocity v L T-1 Acceleration a L T-2 Force F M L T-2 Pressure P M L-1 T-2 Discharge Q L3 T-1 Power P M L2 T-3 W,E M L2 T-2 Density ? M L-3 Dynamic viscosity  µ M L-1 T-1 Kinematic viscosity ? L2 T-1 Surface tension M T-2 Work,energy 7. 3 Methods of Dimensional Analysis The methods of dimensional analysis are: -Buckingham's ? theorem -Ralyeigh's method Buckingham's ? Theorem If there are ‘n' variables in a dimensionally homogeneous equation, and if these variables contain ‘m' fu ndamental dimensions such as (M,L,T) , they may be grouped into (nm) non-dimensional independent ? terms. Mathematically, if a variable x1 depends upon independent variables x2, x3,x4, †¦. ,xn, the functional equation may be written as x1 = f (x2, x3, x4, †¦. , xn) The equation may be written in its general form as 58 f1 ( x1, x2, x3,†¦Ã¢â‚¬ ¦. xn) = C In this equation there are ‘n' variables. If there are ‘m' fundimental dimensions, the according to ? theorem f2 ( ? 1,? 2,? 3,†¦.. , ? n-m ) = C1 e. g Q = f (d,H, µ,? ,g) f1 (Q, d, H,  µ, ? , g) = C n = 6; m = 3; (n-m) = 3 f2 ( ? 1, ? 2, ? 3) = C1 Procedure 1. First of all, write the functional relationship with the given data. 2. Then write the equation in its general form. 3. Choose ‘m' repeating variables and write separate expressions for each term. Every ? term will contain the repeating variables and one of the remaining variables. The repeating variables are written in exponential form . 4.With the help of the principle of dimensional homogeneity, find out the values of the exponents by obtaining simultaneous equations. 5. Substitute the value of these exponents in the ? term. 6. After the ? terms are obtained, write the functional relation in the required form. e. g Q = f ( d, H,  µ, ? , g) f1 (Q, d, H,  µ, ? , g) =C n = 6 , m = 3 , (n-m) = 3 f2 (? 1,? 2,? 3)=C1 Choose ? , g, d as repeating variable, ?1 = ? a1 gb1 dc1 Q ? 2 = ? a2 gb2 d c2 H ? 3 = ? a3 gb3 dc3  µ 59 Selection of Repeating Variable 1. The variables should be such that none of them is dimensionless. 2. No two variables should have the same dimensions. . Independent variables should be as far as possible, be selected as repeating variable. ? > fluid property ? > flow characteristics l > geometric characteristics Example 7. 1 A V-notch weir is a vertical plate with a notch angle ? cut into the top of it and placed across an open channel. The liquid in the channel is backed up and forced to flow through the notch. The discharge Q is some function of the elevation H of upstream liquid surface above the bottom of the notch. In addition it depends upon gravity and upon the velocity of approach Vo to the weir. Determine the form of discharge equation: ?V ? Q = gH 5/2 f ? ,? ? ? gH ? ? ? Q = f (H, g , Vo , ? ) f1 ( Q, H ,g ,Vo, ? ) = C Choose g and H as repeating variables n = 5; n-m =3 ; m=2 ?1 = Ha1 gb1 Q = (L)a1 (LT-2)b1 L3 T-1 ?2 =Ha2 gb2 Vo = (L)a2 (LT-2)b2 LT-1 ?3 = ? (M)o (L)o (T)o = (L)a1 (LT-2)b1 L3 T-1 a1+b1+3 =0 ? a1 = -5/2 -2b1-1 =0 ? b1 = -1/2 ?1 = H-5/2 g-1/2 Q = Q vg H 5/2 (M)o (L)o (T)o = (L)a2 (LT-2)b2 L T-1 a2 = -1/2 60 b2 = -1/2 ?2 =H-1/2 g-1/2 Vo= Vo vgH Q f2 ( gH 5/ 2 Q gH 5/ 2 , Vo ,? gH ) = C1 Vo ,? gH ) Vo ,? gH ) =f( Q = gH 5/2 f ( Example 7. 2 Q = VD 2 f [ Prove that the discharge over a spillway is given by the relation gD H ,] V D where V= velocity of flowD = depth of throat H = Head of water g = Acceleration due to gravity Q= f (V,D,H,G) f1 (Q,V,D,H ,G) = C Choose V and D as repeating variables n = 5, m =2, n-m =3 ?1= Va1 Db1 Q = (LT-1)a1 (L)b1 (L3T-1) ?2 = Va2 Db2 H = (LT-1)a2 (L)b2 (L) ?3 = Va3 Db3 g = (LT-1)a3 (L)b3 (LT-2) M0L0T 0 = (LT-1)a1 (L)b1 (L3T-1) 0 = -a1-1 ; a1 = -1 0 = a1+b1+3 ; b1= -2 ?1 = V -1 D -2 Q 61 ?1 = Q VD2 M0L0T 0 =(LT-1)a2 (L)b2 (L) 0 = -a2 a2+b2+1 =0 ; b2 = -1 ?2 = V0 D-1 H = H/D M0L0T 0 = (LT-1)a3 (L)b3 (LT-2) 0 = -a3-2 ; a3 = -2 0 = a3+b3+1 ; b3 =1 ?3 = V-2 D g gD V = f2 ( gD H , )=0 VD 2 D V Q VD 2 Q , = f( gD H ,) V D Q = VD 2 f ( 7. 4 D H ,) V D HYDRAULIC MODELS Hydraulic models, in general, may be either true models or distorted models. True models have all the significant characteristics of the prototype reproduced to scale (geometrically similar) and satisfy design restrictions (kinematic and dynamic similitude). Model-prototype comparisons have clearly shown that the correspondence of behaviour is often well beyond expected limitations, as has been attested by the successful operation of many s tructures designed from model tests. 7. 5 Hydraulic Similitude To know the complete working and behaviour of the prototype, from its model, there hould be a complete similarity between the prototype and its scale model. This similarity is 62 known as hydraulic similitude. From the subject point of view, the following three types of hydraulic similitude are important. (1) Geometric similitude (2) Kinematic similitude (3) Dynamic similitude GEOMETRIC SIMILITUDE The model and the prototype are identical in shape, but differ only in size. (The ratios of all the corresponding linear dimensions are equal) . Let L = Length of the prototype B = Breadth of the prototype D = Depth of the prototype l,b,d = corresponding values of the model L Linear ratio Lr =Area ratio Ar = ( Volume ratio Vr = ( l = BD = bd L B D )2 = ( )2 = ( )2 l b d L B D ) 3 = ( ) 3 = ( )3 l b d KINEMATIC SIMILITUDE The model and the prototype have identical motions. ( The ratios of the velocities at corresponding points a re equal) Let V1 = velocity of liquid in prototype at point 1 V 2 = velocity of liquid in prototype at point 2 v1,v2 = corresponding values of the model Velocity ratio Vr = V1 V2 = = †¦.. v1 v 2 DYNAMIC SIMILITUDE The model and prototype have identical forces. (The ratios of the corresponding forces acting at corresponding points are equal). F Force ratio Fr = 1 = f1 F2 †¦.. f2 63 7. 6 CLASSIFICATION OF MODELS (1) Undistorted model (2) Distorted model Undistorted model A model which is geometrically similar to the prototype is known as undistorted model. Distorted model Model does not have complete geometric similarity with the prototype, is known as distorted model. 7. 7 Comparison of an Undistorted Model and the Prototype If the model is to be overall similar to the prototype, then all the three similarities (i. e, geometric, kinematic, dynamic ) should exist. But this is not possible in actual practice, as it is difficult to exist two types of similarities simultaneousl y.In general, and undistorted model of a prototype is made keeping in view the geometric similarity only and the remaining similarities are then compared for the scale ratio. 7. 8 Velocity of Water in Prototype for the Given Velocity of an Undistorted Model Consider an undistorted model geometrically similar to a proposed prototype like a weir, dam, spillway etc. Let h = head of water over the model v = velocity of water at a point in the model H,V = corresponding values for the prototype 1/s = scale ratio of the model to the prototype Velocity of water in the model v = Cv v2ghVelocity of water on the corresponding point in the prototype V = Cv v2gH C v 2 gh v = = V C v 2 gH h 1 = H s V = v vs Example 7. 3 The velocity at a point on a spillway model of a dam is 1. 3m/sec for a prototype of model ratio 1:10. What is the velocity at the corresponding point in the prototype? 64 Velocity in the model v = 1. 3 m/s Model ratio, 1/s = 1/10 s = 10 Velocity in the prototype V = v vs V =1. 3 x v10 = 4. 11 m/sec 65 References: 1. Hydraulics and Fluid Mechanics P. N. Modi and S. M. Seth 2. Hydraulics, Fluid Mechanics and Hydraulic Machines R. S. Khurmi 3. Fluid Mechanics Victor L. Streeter

Free Essays on Langston Hughes

Amaris Baxter Langston Hughes; â€Å"Mother to Son† 1) 1930’s; Realism 2) Biographical Theory of Criticism 3) Post-structural Theory of Criticism Through the literary works of Langston Hughes, it is clear to see that he uses his own style and language to portray realistic traits. The biographical theory of criticism can easily be used to criticize Hughes work, as well as the post-structural theory. Realism Hughes poem â€Å"Mother to Son† was written during the Harlem Renaissance. At this time in history, many African Americans expressed their thoughts through music, art, poetry and other areas of the arts. Hughes being a young black men growing up in the 1930’s in America, expressed his opinions of the treatment of blacks through poetry. Writing exactly what he thought, his poems are very realistic, very similar to him. In â€Å"Mother to Son† he lets the readers know that everything in life is not going to be easy and that there are going to be trials that everyone will face in life. Biographical Theory of Criticism â€Å"Mother to Son† Closely parallels the life of Hughes. Born in Missouri, Hughes lived with his grandmother until she died. He was twelve years old. Moving from place to place he learned at an early age that â€Å"life ain’t gonna be no crystal stair.† Since he lived with his grandmother as a child, the mother noted in the title of the poem is symbolic to his grandmother who taught him the values of life. Hughes moved to Harlem after he graduated from high school to continue his education. When people hear of Harlem â€Å"ghetto† comes to mind. Everyone knows that Harlem is not one of the greatest places to live. Living in Harlem most of his life, Hughes can easily relate to the â€Å"splinters and torn up boards† talked about in his poem. Post-structural Theory of Criticism â€Å"Mother to Son† also contains important truth and values about life. This poem is often... Free Essays on Langston Hughes Free Essays on Langston Hughes Langston Hughes was America’s Jazz Poet, the chronicler of life in Harlem in the 1920s. Setting out to write about black Americans, Hughes created a body of work-poetry, fiction, journalism, essays, plays, and song lyrics. While decrying racism and the inequities it created for blacks and other minorities, Hughes called for cooperation among all races. With one ear tuned in to the voices he heard on the street and the other to the music he heard in nightclubs, Hughes created poems that made him one of the stars of the Harlem Renaissance. James Langston Hughes was born in Joplin, Missouri, on February 1, 1902, the only child of James and Carrie Hughes to survive infancy. Another son born two years earlier had died. Carrie Hughes came from a family that had been prominent in the abolitionist movement. A lover of books and plays, she had once dreamed of becoming a professional actress. Instead, like so many black women of her time, she had to settle for the jobs she could find, working as a stenographer and a waitress. Smith 2 James Hughes wasn’t able to pursue his professional goals. Hardworking and ambitious, he earned a law degree, but racism made it impossible to sustain his practice. Frustrated by limited opportunities in the United States, he left Missouri for Mexico before his son was two years old. Though he periodically sent money, he never lived with his family again. When his father left for Mexico in 1903, Langston and his mother moved to Kansas, where her mother, Mary Langston lived. For ten years Langston lived with his grandmother as his mother moved from town to town in search of a decent job. Langston suffered not only from poverty but also from restrictions that came with living in a segregated community. While he attended an integrated school, he wasn’t permitted to take part in its team sports. In spite of these obstacles, Langston developed a natural sense of self-confidence. Langston le... Free Essays on Langston Hughes Poetry is the art of writing thoughts and stories in verse using specific language; language selected for its beauty, sound and ability to convey emotions. Langston Hughes was one of America’s most influential writers. He made a large contribution not only to literature but to American culture, as well. James Mercer Langston Hughes was born in Joplin, Missouri, on February 1, 1902, to James Nathaniel Hughes, a lawyer and businessman, and Carrie Mercer Hughes, a teacher. In 1921 Hughes moved to New York and attended Columbia University (he also attended Lincoln University and graduated in 1930). In 1923 Hughes left New York for Africa. It was around this time that Langston wrote â€Å"I’ too† one of his most powerful and famous poems. Throughout his life he also toured many parts of the world holding odd jobs and living in many different cultures; including Asia, Haiti and Cuba. As well as being a highly recognized poet he was also a novelist, reporter, translator, playwright and a short story writer. The poems I choose are â€Å"I, too† and â€Å"Let America be America again†. Each one of these works is challenging and both seem to have unique while altogether similar meanings. â€Å"Let America be America again† seems as though it could be looked at as an extension of â€Å"I, too†. In â€Å"Let America be America again Langston states: â€Å"Seeking a home where he himself is free†¦ Where never kings connive nor tyrants scheme That any man be crushed by one above.† It seems to me that is what he is also â€Å"seeking† in â€Å"I, too†. In â€Å"I, Too†, Hughes gives a voice to the frustration encountered by African Americans when they were denied their basic rights as citizens of America, during the times of slavery. The poem expresses the second class status of given to African Americans and gives a voice to a people who are tired of being treated as second class citizens. The poem begins with, â€Å"I, too sing Amer... Free Essays on Langston Hughes Langston Hughes Langston Hughes opened his first volume of poems with the expression of his– and every Negro’s– â€Å"soul world†: â€Å"I am a Negro: /Black as the night is black, /Black like the depths of my Africa† (Emanuel 17). When the women at the box office of the only movie theatre in Lawrence, Kansas pushed the twelve-year old boys nickel back and pointed to a new sign â€Å"Color Not Admitted,† she laid a shaping hand on that world. Hughes spent a lifetime illuminating that world through poems, stories, novels, lectures, and various other literary forms – with virtuosity and understanding so unmatched that he has been unofficially granted the title as Negro Poet Laureate and Dean of Negro Writers in America. Langston Hughes’ early life prepared him well to write about humanity, for as a child and young man he lived in different places and met many different kinds of people. His growing up years were, altogether, not very happy. But they provided him with experiences that many people never have. Born to Nathanial Hughes and Carrie Mercere on February 1, 1902 in Joplin Missouri, young Langston form the very start was a very bright and curious child (Haskins 2). But his home life was neither happy not very secure. His parents did not get along well. There were often many arguments about money. Mr. Hughes was a â€Å"penny – pincher†; he seemed to resent event the necessary expenses, except when it came to clothes for himself. There were also arguments about moving. Mr. Hughes was a lawyer, Langston’s mother thought her husband would be able to find work in another city, however Mr. Hughes was convinced there was no city in the racially segregated United States wh ere he could find opportunity. Finally, Mr. Hughes announced that he was leaving. Hughes spent a lonely boyhood after his mother and father split, living his first twelve years with his grandparents and friends of the family in Lawrence, Kansas. His moth... Free Essays on Langston Hughes Amaris Baxter Langston Hughes; â€Å"Mother to Son† 1) 1930’s; Realism 2) Biographical Theory of Criticism 3) Post-structural Theory of Criticism Through the literary works of Langston Hughes, it is clear to see that he uses his own style and language to portray realistic traits. The biographical theory of criticism can easily be used to criticize Hughes work, as well as the post-structural theory. Realism Hughes poem â€Å"Mother to Son† was written during the Harlem Renaissance. At this time in history, many African Americans expressed their thoughts through music, art, poetry and other areas of the arts. Hughes being a young black men growing up in the 1930’s in America, expressed his opinions of the treatment of blacks through poetry. Writing exactly what he thought, his poems are very realistic, very similar to him. In â€Å"Mother to Son† he lets the readers know that everything in life is not going to be easy and that there are going to be trials that everyone will face in life. Biographical Theory of Criticism â€Å"Mother to Son† Closely parallels the life of Hughes. Born in Missouri, Hughes lived with his grandmother until she died. He was twelve years old. Moving from place to place he learned at an early age that â€Å"life ain’t gonna be no crystal stair.† Since he lived with his grandmother as a child, the mother noted in the title of the poem is symbolic to his grandmother who taught him the values of life. Hughes moved to Harlem after he graduated from high school to continue his education. When people hear of Harlem â€Å"ghetto† comes to mind. Everyone knows that Harlem is not one of the greatest places to live. Living in Harlem most of his life, Hughes can easily relate to the â€Å"splinters and torn up boards† talked about in his poem. Post-structural Theory of Criticism â€Å"Mother to Son† also contains important truth and values about life. This poem is often... Free Essays on Langston Hughes Langston Hughes Poet, novelist, journalist, playwright, essayist, and songwriter: all of these words describe a man who is said to be one of the twentieth century’s most respected and often controversial writers. This man’s main mission was to help enlighten people on the racial issues that were before them (Berry 5). At that time, this man was only the second black person to make a living as a writer (Harper 5). His name was Langston Hughes, and he crossed numerous racial barriers and gained widespread popularity while criticizing racism. Shaped by his parents, childhood, and life experiences, Langston Hughes became one of the most influential Black Americans of his time. Langston Hughes was born February 1, 1902, to James and Carrie Hughes. James Hughes had a law degree, but was unable to maintain a law practice because of racism. Carrie Hughes, a prominent activist in the Abolitionist Movement, had big dreams of becoming an actress, but her dreams were as well crushed by racism. Instead of keeping to their dreams, his parents had to settle for whatever job they could find. Hughes’ father, being frustrated with job opportunities, moved to Mexico when his son was not even two years-old. His mother then moved to Lawrence, Kansas, where Hughes’ grandmother, Mary Langston, lived. While his mother moved from town to town in search of work, Hughes spent his time with his grandmother, from whom he learned self-confidence. He learned from her how to endure many things, including hardships, without losing his pride and dignity (Berry 7). At the age of twelve, his grandmother died and he went to live with his mother in Lincoln, Illinois, where he attended high school. He was there elected class poet where he wrote a poem for graduation ceremonies and got such an applause from them that he decided to become a poet. Many in his school where immigrants therefore there were few racial conflicts. He often took int... Free Essays on Langston Hughes Langston Hughes and Zora Neale Hurtson are two poets with very similar motives from the Harlem Renaissance. In the 1920’s and 1930’s many there was an outburst in all fields or art with African-Americans. Beginning as a series of literary discussions in the lower Manhattan (Greenwich Village) and upper Manhattan (Harlem) sections of New York City, this African-American cultural movement became known as "The New Negro Movement" and later as the Harlem Renaissance. Hughes and Hurston shared very similar views on how the color of your skin greatly affects your life, and also optimistic thoughts for an uprising in the African-American Culture. Langston Hughes thought he was no different from a white person. He knew that inside all people are same and should have equal opportunities in their life. This wasn’t the case due to the common person’s racist views. You can see Hughes views on this in Black and Blue, in which he says," I’m white inside but, that doesn’t help my case." Zora Neale Hurston felt very similar to Langston Hughes in which she knew there was no difference between blacks and whites and that it was only people’s prejudice that made the two stand out form one another. You can see Hurtson’s views on the color of her skin on in How it Feels to Be Colored Me. Hurston’s thoughts are very similar to Hughes, in which she says," But I am not tragically colored. There is no great sorrow up in my soul, nor lurking behind my eyes." You can see how Hurston knew it was the prejudice of the white person, which made African-Americans stand out in which she says," I feel most colored when I am thrown against a sharp white contrast" and " He is so pale with his whiteness then I am so colored." Zora Neale Hurtson thought the best for the Negro race. She knew that one day equality would be recognized and white people would feel sympathetic for their inexcusable prejudice. Langston Hughes felt the same wa... Free Essays on Langston Hughes Langston Hughes Research Paper During the 1920s many artists came to Harlem to express themselves. Many of these shriving artists were African-Americans and looking for opportunities. One of the most recognized of these African-American artists was Langston Hughes. Hughes wrote of his experiences as an African-American and expressed his struggles in various poems. Such poems are â€Å"Dream Variation† and â€Å"The Negro Speaks of Rivers†. Langston Hughes was born in 1902 in Joplin Missouri. Soon after his birth, his parents separated. James Nathaniel, Hughes’ father, left him, and went back to Cuba to work as an attorney. Hughes lived with his grandmother and mother Carrie Mercer in the United States. It was with her that Hughes’ learned of his grandfather’s history and the â€Å"constant discrimination that would haunt him in life as he struggled for freedom.† (Gale Net Resource Biography Page 2) After his grandmothers’ death in 1910, he went to live with his mother and stepfather in Cleveland, Ohio where he attended Central high school. It was there that he discovered his passion for writing while working for the high school magazine, and also edited the school yearbook. Hughes dropped out of Columbia University to work odd jobs to support himself and his mother who moved into Harlem. After spending the next two years in poverty overseas in Italy and France, he returned to his mot her and half-brother in Washington D.C. It was there that Hughes was discovered, when he â€Å"attracted the attention of poet Vachel Lindsay by intentionally placing three of his poems of Lindsay’s dinner table.† (Gale Net Resource Biography Page2) After this discovery, reporters flocked to Hughes to listen to his works. Following this event, Hughes proceeded to attend Lincoln University in Pennsylvania, where he continued writing poetry, short stories, and essays. With the help of critic and art patron Carl Van Vechten, Hughes published his first ...

Frequencies and Relative Frequencies in Histograms

Frequencies and Relative Frequencies in Histograms In the construction of a histogram, there are several steps that we must undertake before we actually draw our graph. After setting up the classes that we will use, we assign each of our data values to one of these classes then  count the number of data values that fall into each class and draw the heights of the bars. These heights can be determined by two different ways that are interrelated: frequency or relative frequency. The frequency of a class is the count of how many data values fall into a certain class wherein classes with greater frequencies have higher bars and classes with lesser frequencies have lower bars. On the other hand, relative frequency requires one additional step as it is the measure of what proportion or percent of the data values fall into a particular class. A straightforward calculation determines the relative frequency from the frequency by adding up all the classes frequencies and dividing the count by each class by the sum of these frequencies. The Difference Between Frequency and Relative Frequency To see the difference between frequency and relative frequency we will consider the following example. Suppose we are looking at the history grades of students in 10th grade and have the classes corresponding to letter grades: A, B, C, D, F. The number of each of these grades gives us a frequency for each class: 7 students with an F9 students with a D18 students with a C12 students with a B4 students with an A To determine the relative frequency for each class we first add the total number of data points: 7 9 18 12 4 50. Next we, divide each frequency by this sum 50. 0.14 14% students with an F0.18 18% students with a D0.36 36% students with a C0.24 24% students with a B0.08 8% students with an A The initial data set above with the number of students who fall into each class (letter grade) would be indicative of the frequency while the percentage in the second data set represents the relative frequency of these grades. An easy way to define the difference between frequency and relative frequency is that frequency relies on the actual values of each class in a statistical data set while relative frequency compares these individual values to the overall totals of all classes concerned in a data set. Histograms Either frequencies or relative frequencies can be used for a histogram. Although the numbers along the vertical axis will be different, the overall shape of the histogram will remain unchanged. This is because the heights relative to each other are the same whether we are using frequencies or relative frequencies. Relative frequency histograms are important because the heights can be interpreted as probabilities. These probability histograms provide a graphical display of a probability distribution, which can be used to determine the likelihood of certain results to occur within a given population. Histograms are useful tools to quickly observe trends in populations in order for statisticians, lawmakers, and community organizers alike to be able to determine the best course of action to affect the most people in a given population.

Writing Your Graduate School Admissions Essay

Writing Your Graduate School Admissions Essay It should come as no surprise that most applicants do not enjoy drafting their graduate admissions essay. Writing a statement that tells a graduate admissions committee all about you and can potentially make or break your application is stressful. Take a different perspective, however, and you will find that your admissions essay is not as daunting as it seems. What is its Purpose? Your graduate school application provides the admissions committee with a great deal of information about you that cannot be found elsewhere in your graduate application. The other parts of your graduate school application tell the admissions committee about your grades (i.e., transcript), your academic promise (i.e., GRE scores), and what your professors think of you (i.e., recommendation letters). Despite all of this information, the admissions committee does not learn much about you as an individual. What are your goals? Why are you applying to graduate school? With so many applicants and so few slots, its critical that graduate admissions committees learn as much as possible about applicants so as to ensure that they choose students who best fit their program and are most likely to succeed and complete a graduate degree. Your admissions essay explains who you are, your goals, and the ways in which you match the graduate program to which you are applying. What Do I Write About? Graduate applications often ask that applicants write in response to specific statements and prompts. Most prompts ask applicants to comment on how their backgrounds have shaped their goals, describe an influential person or experience, or discuss their ultimate career goals. Some graduate programs request that applicants write a more generic autobiographical statement, most often referred to as a personal statement. What is a Personal Statement? A personal statement is a general statement of your background, preparation, and goals. Many applicants find it challenging to write a personal statement because there is no clear prompt to guide their writing. An effective personal statement conveys how your background and experiences have shaped your career goals, how you are well matched to your chosen career and provides insight into your character and maturity. No easy feat. If you are asked to write a generic personal statement, pretend that the prompt instead requires you to discuss how your experiences, interests, and abilities have lead you to your chosen career. Begin Your Admissions Essay by Taking Notes About Yourself Before you write your admissions essay you must have an understanding of your goals and how your experiences to date prepare you for pursuing your goals. A self-assessment is critical to gathering the information you need to write a comprehensive essay. You likely will not (and should not) use all of the information that you gather. Evaluate all of the information you gather and determine your priorities. Most of us have many interests, for example. Decide which are most important to you. As you consider your essay, plan to discuss the information that supports your goals and what is most important to you. Take Notes on the Graduate Program Writing an effective graduate admissions essay requires knowing your audience. Consider the graduate program at hand. What specific training does it offer? What is its philosophy? How well do your interests and goals match the program? Discuss the ways in which your background and competencies overlap with the graduate programs requirements and training opportunities. If youre applying to a doctoral program, take a close look at the faculty. What are their research interests? Which labs are most productive? Pay attention to whether faculty take on students or appear to have openings in their labs. Peruse the department page, faculty pages, and lab pages. Remember That an Admissions Essay is Simply an Essay By this time in your academic career, you have likely written a great many essays for class assignments and exams. Your admissions essay is similar to any other essay you have written. It has an introduction, body, and conclusion. Your admissions essay presents an argument, just as any other essay does. Granted, the argument concerns your capacities for graduate study and the outcome can determine the fate of your application. Regardless, an essay is an essay. Beginning is the Hardest Part of Writing I believe this holds true for all types of writing, but especially for drafting graduate admissions essays. Many writers stare at a blank screen and wonder how to begin. If you search for the perfect opening and delay writing until you find just the right angle, phrasing, or metaphor you may never write your graduate admissions essay. Writers block is common among applicants writing admissions essays. The best way to avoid writers block is to write something, anything. The trick to beginning your essay is to not start at the beginning. Write the parts that feel natural, such as how your experiences have driven your career choices. You will heavily edit whatever you write so dont worry about how you phrase your ideas. Simply get the ideas out. It is easier to edit than write so your goal as you begin your admissions essay is to simply write as much as you can. Edit, Proof, and Seek Feedback Once you have a rough draft of your admissions essay, keep in mind that it is a rough draft. Your task is to craft the argument, support your points, and construct an introduction and conclusion that guides readers. Perhaps the best piece of advice I can offer on writing your admissions essay is to solicit feedback from many sources, especially faculty. You may feel that you have made a good case and that your writing is clear, but if a reader cannot follow it, your writing isnt clear. As you write your final draft, check for common errors. Perfect your essay as best you can and once its submitted congratulate yourself for completing one of the most challenging tasks entailed in applying to graduate school.​

Communications Coursework Example | Topics and Well Written Essays - 1500 words

Communications - Coursework Example The movement of structuralism is closely connected to the study of signs and symbols and how individuals created meanings of these signs and symbols. The movement of structuralism is said to have been originated in the theories of Ferdinand de Saussure during the early period of the 1900s (Berger, 2006, p.20). Saussure was the one who developed signs and symbols and believed that all languages constitute of difficult system of symbols and these symbols help in expressing ideas and there are certain regulations that are governing the way these symbols are used. He asserted that any particular symbol is a matter of chance and a link does not exist between a word and the meaning attached to it. For example: the word â€Å"dog† does not signify an image of an animal. Structuralism even states that a literary piece of work has zero origin and the individual authoring a piece of literary work simply occupies an already existing language which assists him/her in created sentences for his/her story. 2. Culler states that society is a primary reality, by this statement he is entering into an argument against Ferdinand de Saussure who is of the idea that human beings are the ones who have created society and the society itself was not created first (Berger, 2006, p.14). Basically, Culler is entering into a chicken and egg debate in which the issue is whether chicken created eggs or the eggs created chicken. Culler is arguing that it was not the humans who created the society, and society preceded human beings. Culler states that the society is not an outcome of behaviors conducted by human beings and is not demonstration of the human mind. Culler even stated that if an individual wants to conduct a study on human behavior and wants to analyze human behavior, he/she should first study the society and he even added that meanings are derived when an individual interacts with the society and thus they should be explained in the context of the society. Culler has raise d a significant debate against the assumptions of structuralism, this is because if the society would not have existed human beings would not have learned how to interpret the meaning of a specific sign or object and this is because the meaning of science do not evolve out of nowhere, they are created by the society. The society is very important for the development of communication as due to its existence, humans learn how to speak and write and learn meanings of different signs and symbols. 3. The patterns in which stories and speeches are narrated and told are a huge field of study and one of the greatest theorists who contributed to this study was William Labov during 1972 (Berger, 2006, p.40). According to Labov there are six steps if story telling starting from abstract in which an overview of the story is provided. For example: In a recent speech on animal behavior I attended, the speaker started by proving an overview of what he is going to talk about. Next comes the orienta tion in which the speaker informed us about which animals he is going to talk about, their behaviors at under different situations and the reasons for exhibiting that behavior. Next is the complicating action in which the speaker informed us about the events in which he will narrate the entire topic starting off with a background, concentrating on theorists and application of theories and in the end he concludes. Next he provided an evaluation of the events

Choose one Essay Example | Topics and Well Written Essays - 1500 words

Choose one - Essay Example – This is the thesis†¦ II. The Progressive Period The Progressive Period in the US approximately started in 1890 to 1920 as a social movement that grew into a political movement, and somewhere in 1900 to 1918, was the training ground for a transformation of the relationship between a democratic government and the people, essentially highlighting Prohibition and woman suffrage (PBS; GWU). This period was also generally referred to as the transition from agrarian to urbanization, a depiction of more advanced transformation of the civilization and high level way of thinking. III. World War II On the other hand, World War II began in 1939 to 1945, and women were considered partners in winning the war due to the following points: there was a changed image of women’s roles, they joined the nurse corps and armed forces, they were encouraged to serve the military, they filled in traditional male jobs particularly in production, and they performed functions both at home and in the community and so on (National Women’s History Museum). The point is that women were started to be viewed as equal with men and that made them essential counterparts in order for the US to successfully win the war. IV. Post-War Expansion Period Right after the World War II is the Post-War Expansion Period. ... After all, Post-War Expansion Period was the economic expansion of the US, by which women had special participation in the process. V. Analysis It is evident, based on the information as stated so far that the transition in the US history of development over the course of time was fueled by social, political and economic factors. However, men and women substantially worked out for this. Therefore, having the thought like this will pave the way for understanding that the involvement of women in particular in the entire scenario of development is not just only a sole controversial issue, but a specific subject that requires fundamental analysis to understand its actual transformation as directly influenced by socio-economic and political factors. What therefore is one of the most important actions to take is to know the varying attitudes to women’s roles in the workforce in each of the three introduced periods. Another important point is to further analyze how these attitudes we re changed. Finally, to understand why these attitudes changed is just another important point to consider. Clearly, women were not considered equal counterparts of men from the beginning and this was due to social understanding linked in particular to a patriarchal society in the US and even in other parts of the world. This dates back to the beginning, but what is much more explicit observation was the aggressive considered nature of men by then, as depicted from their ability to conquer. Such history remains vivid in the minds of the Americans especially supplemented by one of the thoughts like on how Christopher Columbus discovered, subjugated and put the entire native America

Privacy and confidentiality ( health care ethics) Essay - 1

Privacy and confidentiality ( health care ethics) - Essay Example it, I see or hear, in the life of men, which ought not to be spoken of abroad, I will not divulge, as reckoning that all such should be kept secret† (as translated by Francis Adams). Why is it appropriate that the healthcare practitioners to keep mum over the medical conditions of patients? It just makes practical sense that medical professionals should uphold the confidentiality of their clients. This is because in the clinical setting patients are expected to fully disclose their habits, their ailments, their strengths, and their weaknesses. Beyond this, they are frequently required to undress and allow physicians access to their bodies for examination, treatments, and surgery. Thus, the patient is vulnerable, needy, and prone to feelings of shame. Patients endure these experiences because they want to be treated for what ails them and because they trust their physicians to keep their secrets. If this trust were eroded, it might follow that patients would become unable to seek medical attention or they will be hesitant to disclose some information that is vital for their treatment. Most often, dilemmas arise when medical practitioners should or should not disclose patient information. For, example, confidentiality is regarded as crucial by those involved in the care of mentally ill or emotionally disturbed patients. A stigma has traditionally surrounded those with mental disorders. This is why the preservation of confidentiality is necessary to ensure that patients are prepared to come forward for treatment and that they continue with treatment. Patients require that assurance. They do not want the risk of becoming the butt of cruel jokes and being socially ostracized. Another example, in family research, is that when both the husband and wife may report on sensitive topics such as his and her own and the partner’s extramarital relationships, marital aggression, or alcohol use. Margolin et al. (2005) revealed that the â€Å"standard safeguard for discomfort

Walmart case study Example | Topics and Well Written Essays - 750 words

Walmart - Case Study Example This together with the ‘open door policy’ states that management needed to consider the â€Å"associates† views in the decision making process. Walton was against worker unionization and he argues that it would lead to establishment of restrictive work regulations and dramatic pay hikes. Furthermore, he came up with the â€Å"sun down rule† which encouraged workers to complete their tasks on time (Hill and Jones, 2009). His policies were based on getting workers to perform to their level best while paying the insufficient salaries. However, they would be rewarded in stock ownership plans and profit sharing schemes. This strategy has worked for years nonetheless; it has been facing issues in the recent times. Issues Facing This Strategy This strategy has led the company to great heights and sustained its exemplary financial performance over the years. Over the recent past, there have been various issues emerging from the application of this strategy (Anthony , Kacmar and Perrewe, 2002). Wal-Mart is the private entity with the highest number of â€Å"associates† world over. This has created numerous problems with regards to human resource management. In the past, the company has been relying on the strategy of encouraging the employees to work hard with the promise of getting a promotion or incentives through stock ownership and profit sharing. This strategy has been regarded as being highly unfair as workers are exploited to work for long hours and they are not duly compensated for their contribution. Furthermore, it has been observed that the company rarely fulfills its promise of sharing its employees through profit sharing. The company has been faced by several law suits over pressuring their employees to work for long hours without paying them overtime wages. Moreover, the company has been under attack for paying its employees peanuts and pressuring them to work too hard (Heskett, 2011). This has resulting to increasing dissa tisfaction among the workforce and can be attributed to the decline in the company’s performance in the recent past. This policy is aimed at increasing the company’s productivity while totally ignoring the â€Å"associates† plight and contribution towards the company’s success. In most competitive firms, worker remuneration is based on output and this should be the case for the giant retailer. Labor unions have attempted to intervene but to no avail. The company’s â€Å"associates† are continually oppressed as its reputation and financial glory go down the drain. Labor unions have made concerted efforts to unionize the employees over the years but they have fallen on deaf ears. Wal-Mart has been noted to be one of the few companies that have strongly opposed against unionization of the â€Å"associates†. The company management argues that labor unions champion for increased salaries and impose strict working regulations (Heskett, 2011 ). This move is regarded to be highly capitalistic and aims at maximizing the company’s profits at the workers’ expense. This has created negative publicity concerning the company and if no immediate action is taken, it could have further detrimental effects on its profitability. In addition to, the company has

There is No universal experience of 'childhood' - it is a construct Essay

There is No universal experience of 'childhood' - it is a construct entirely dependent on patterns of social organisation and cultural conventions Discuss with - Essay Example This is the beginning of shaping a child to think and act like the parent. In this process, children are taught how to behave and how to move within their culture. Depending on how the child is treated they will either develop a strong character and self-esteem or they will develop one that is weak. A child is taught to perceive the world through their parents eyes and they willing accept this teaching. The biggest influence on childhood will be the culture, religion, economic and social aspects of the family. Rodd (1996) says that culture plays a significant role in childhood and it can be the mainstream culture or it can be a subculture (Rodd, p. 31). Shechtman Hiradin and Zina (2003) talked with adolescents in their study to find out whether there was a difference in how these children would disclose about them based on their ethnicity. Their study found that Moslem children were able to disclose easier than Druze children and they thought it may be due to how much acculturation each ethnic group displayed. Druze people re more traditional in their ways and less acculturated to the mainstream than Moslem and Jewish children according to their findings. This information shows that there is some truth to the idea that culture plays a part on how a child learns. It is the opinion of this writer that culture is a very big part of how children accept certain things in their environment. For instance, many children grow up and are abused in their childhood. Often this leads to abusive adults. The culture can also teach a child to love or to hate, to express themselves well or to be introverted and shy. There are a variety of cultural challenges to a child both inside the home and outside because they are constantly being bombarded by cultural situations. Harris (1999) says that what a parent does may not matter to a childs growing up. She gives examples of how one culture (that of the 1950s) taught parents not to spoil their children. Today, parents are

New Zealand Economy Essay Example | Topics and Well Written Essays - 1750 words

New Zealand Economy - Essay Example The intermingled culture was a blend of their traditions to create a rich cultural mix; with the blend it threated the survival of the Maori people. The New Zealand`s Government is working to promote the growth of its people, as it tries to preserve its culture. The New Zealand people are working together with the government to promote the country so as to make it a better place to live for its people (Britton 4). The country was discovered in December 1642, by Tasman (Britton 4). It has an ocean environment that keeps the climate mild with the prevailing westerly winds; this causes fluctuation of temperatures and rainfalls from East to West. New Zealand experiences the four seasons of winter, spring, summer, and autumn (Smelt 13). It is a rich and complex economy, with a unique society. The economy of New Zealand has been built for over a hundred and fifty years; some of the economic aspects were gotten from the Polynesian heritage, as well as the European culture (Hawke 1). The main economic activities of New Zealand were dependent on the success of wool, dairy, and meat export (Rewi 21). Like many other countries, New Zealand is in search of ways to boost its economic activity. New Zealand economic growth continued until the First World War, but there were economic interruptions. During the 1920s, the nation was marked with economic uncertainties, and in 1930s it experienced a great depres sion. New Zealand saw its exports restrained by limited growth of demand for meat, wool, and dairy products in 1920s, and was affected by the falling prices of these products in the 1930s. Hawke points out that â€Å"The depression of the 1930s was a major social political event in New Zealand’s history, even if the experience of poverty and unemployment was not great by international standards† (6). Export prices guided the recovery from the depression, while in the meantime, North American and European economies also recovered. The depression in New Zealand brought to power a Labor government, and when this government came across economic problems, it chose to use the unorthodox policies. The depression was combined with the efforts to protect the economy of New Zealand from international events. New Zealand’s economy changed during the 1930s with the regulation of imports and exchange controls, which linked to aspects of a reserved and secured economy (Hawke 6).New Zealand is a small open economy that relies on trade and financial markets trends to ensure output performance, and its vaporization linked to development in the rest of the world. The dependence on New Zealand’s growth leaves it vulnerable to economic performance in the market. Financial markets are an important passage way in which New Zealand’s business cycle is influenced by the United States economies (IMF 3). Robert Reich of Labor Party brought New Zealand to foresee the twenty-first century deficit of national products, corporations and industries. For many years, New Zealand`s economy was built on â€Å"free markets† and â€Å"free trade†, and investment seemed invincible (Kelsey 1).The enthusiasts wanted to advance the process more swiftly, but critics came up with ways to mitigate the unfavorable effects of globalization, particularly on the environment and labor. The â€Å"‘unrealistic critics’ denounced the growing inequal ities and poverty and warned of erosion of democracy and the potential for unregulated capitalism to implode† (Kelsey 1). After many years of fundamental theory-driven transition, it was surprising that the people of New Zealand of 1990 began to acknowledge the importance of their political and social world in Government

There is No universal experience of 'childhood' - it is a construct Essay

There is No universal experience of 'childhood' - it is a construct entirely dependent on patterns of social organisation and cultural conventions Discuss with - Essay Example This is the beginning of shaping a child to think and act like the parent. In this process, children are taught how to behave and how to move within their culture. Depending on how the child is treated they will either develop a strong character and self-esteem or they will develop one that is weak. A child is taught to perceive the world through their parents eyes and they willing accept this teaching. The biggest influence on childhood will be the culture, religion, economic and social aspects of the family. Rodd (1996) says that culture plays a significant role in childhood and it can be the mainstream culture or it can be a subculture (Rodd, p. 31). Shechtman Hiradin and Zina (2003) talked with adolescents in their study to find out whether there was a difference in how these children would disclose about them based on their ethnicity. Their study found that Moslem children were able to disclose easier than Druze children and they thought it may be due to how much acculturation each ethnic group displayed. Druze people re more traditional in their ways and less acculturated to the mainstream than Moslem and Jewish children according to their findings. This information shows that there is some truth to the idea that culture plays a part on how a child learns. It is the opinion of this writer that culture is a very big part of how children accept certain things in their environment. For instance, many children grow up and are abused in their childhood. Often this leads to abusive adults. The culture can also teach a child to love or to hate, to express themselves well or to be introverted and shy. There are a variety of cultural challenges to a child both inside the home and outside because they are constantly being bombarded by cultural situations. Harris (1999) says that what a parent does may not matter to a childs growing up. She gives examples of how one culture (that of the 1950s) taught parents not to spoil their children. Today, parents are