Maturity :: essays research papers

Maturity   Ã‚  Ã‚  Ã‚  Ã‚  Maturity is not something that happens overnight. Maturity comes through trial and error; it’s a process which has to be perfected. Life throws curveballs and there are always multiple ways to deal with the situations. Being mature is making the right choices and knowing right from wrong.   Ã‚  Ã‚  Ã‚  Ã‚  When you turn eighteen you are expected to just be mature. You’re allowed to buy a house, a car, get a credit card, it seems like you can do whatever you want. Maturity basically gets thrown at you, so hopefully you are prepared for it. High school responsibilities, like getting a job, budgeting your time and learning to drive teach you skills that you can use in your adult life, if you choose to apply them. Maturity is about choice. You can be given every skill that you need to survive and if you are mature enough you will use them.   Ã‚  Ã‚  Ã‚  Ã‚  For me, driving a car, going to Europe, graduating, and having a job have all contributed to my maturity. I have to make life and death choices every day while driving, and my choices affect other’s lives- and that bring a lot of maturity. I went to Europe basically by myself, with no parent there to hold my hand. I had to make good choices, be safe and be mature while I was half way across the world from my parents. I am graduating this year as well. After this summer I am going to college, being a real â€Å"adult† and I will be able to make my own choices. Maturity will help me keep my head on straight while I am being my own boss. For the past two years I have held the same job. This job has taught me responsibility, how to deal with money and people and basic life skills. If I were not mature I would not be able to hold a job for that long.

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

ADHD in the United States - Free Essay Example

Sample details Pages: 9 Words: 2767 Downloads: 10 Date added: 2019/08/07 Category Medicine Essay Level High school Tags: ADHD essay Did you like this example? Did you know that there has been a 42% increase in ADHD diagnosis over the past 8 years as well as more than 5% of children in the United States are being treated for ADHD with medication? That means that 6.4 million american children from age 4 to 17 have been diagnosed with ADHD! Research states that those living below the poverty line are more susceptible to have ADHD. The fact that the conditions Attention Deficit Disorder, Attention Deficit Hyperactivity Disorder, and Oppositional defiant disorder have become more prevalent in our society should make every American question the reasons as to why these disorders were never such a big issue hundreds of years ago. If we look back in American history, we only start to see true diagnosis and treatment of such conditions in the mid 50s and even then, the condition was vaguely diagnosed. Don’t waste time! Our writers will create an original "ADHD in the United States" essay for you Create order When using the same diagnostic criteria (DSM) to diagnose children in other countries, the widespread presence of these disorders were slightly lower, but the criteria is so general, that if the world population took the diagnostic criteria, more than a third of the world would fall victim to these disorders and would have to be placed on medications to treat their symptoms. The thing that boggles my mind is how fast these doctors are willing to prescribe such medications to patients who have only been attending their care for a short period of time. There is rarely any precautionary statements that parents are told as far as the dangers of these manufactured medications that are so widely being administered to children across the US. The pharmaceutical companies simply want the parents to buy the medications to help better their childrens lives. This way of retailing their poison is to the population stimulates a sense of unnoticed inferiority so that the anti authoritarian minds, that could possibly change the world, are hushed out of existence and is instead drugged by authoritarians to assist people that supposedly have disabilities. The absurdity of such brainwashing is only meant to fill the pockets of the elite with their answer to all your problems pill and dumb down the future revolutionists. The dark lies that they have been telling poor victim s that can barely afford medications for every little problem that they supposedly have must be exposed. It is unbelievable to see the radical shift that has been taking place in this country ever since Big Pharma has been supposedly treating people to help them with their problems. If a child has too much fun playing and is running around, give him some ritalin; if a man is unhappy with his size, give him a magical pill to reduce the size of his body. Unfortunately, there are many doctors that do not devote their time to the patients they have for to be consistent in checking in with the well being of their patients and instead care about the money they will get by prescribing medication. Most doctors dont want to see anyone suffer, so it is our instinct to really try to help people, Avitzur said. At the same time, were very busy nowadays in practices, and patients dont get the same face-to-face time that perhaps they did 10, 20 years ago. And so in a way its easier to write a prescription than to have to go into a lengthy discussion about why Im not going to write you a prescription ( Cohn). Some of these Doctors shouldnt be considered Doctors if they simply went to school to gain the right to prescribe life changing medication to their patients. There has to be a different approach that doctors must take if they truly want to be faithful to their patients. Doctors should first and foremost be an ear to hear out the situation and should help their patients understand that prescribed medication is the last resort to assist them with their problem. Depression runs rampant in our ever increasing authoritarian society, and it only gets worse because it is being treated by professionals as a dire condition and is in some cases as a disease. To sum up what doctors think of depression, to them it is a mental health disorder characterized by persistently depressed mood or loss of interest in activities, causing significant impairment in daily life. People who are experiencing depression were never born with this mental health disorder, something triggered their depression, and everyone can get over depression because it is simply prolonged sadness. Many depressed people choose to stay in that state of mind, some of them may rely on medications to cure them of their condition, and others decide to find something in their walk of life that will a ssist them to get over whatever they are going through. A study on depression reveals that, To better understand how depression arises, the researchers looked for specific causes within the brain cells. This led them to a small organelle found within brain cells called mitochondria. Mitochondria are the main source of energy for cells, but they also help to regulate brain function (Frontiers). There are numerous studies on herbal remedies that can raise ATP production in the brain such as D-Ribose and Black Ant Extract that will assist in overall health, but it will not eliminate all of your problems, nothing will, they are merely meant to assist you with health and boost your positive attitude if you have one. Instead of some doctors doing hard research to prove their case, they want to hear whatever scratches their itching ears so they can just look at you silly and shut you up with a prescription to a medication that will essentially worsen your problems while smiling and saying everything will be alright if you take this pill and come back for refills. Most doctors nowadays do not want to hear the words, what are the side effects? It is unfortunate that many doctors just want money in their pockets so they give you whatever will temporarily relieve your prob lems. The corruption of these pharmaceutical companies do not get as much attention as they should, especially due to the large scale production and distribution rate of these brain altering chemicals in the United States alone. The doctors who are administering these drugs rarely divert the attention of their patients to other remedies that can not only be beneficial to their health, but also to assist their ability to recover. What a better way to maintain the status quo than to view inattention, anger, anxiety, and depression as biochemical problems of those who are mentally ill rather than normal reactions to an increasing authoritarian society. Do we really want to diagnose and medicate everyone with deficits in rule governed behavior? Americans have been increasingly socialized to equate inattention, anger, anxiety, and immobilizing despair with a medical condition and to seek medical treatment rather that political remedies (Levine). If we take a step back and look at the rate at which opioids have taken the lives of people across the US, we realize that along with these opioid related deaths, there is an almost identical overprescription rate of opioids to civilians who have do not need such drugs fo r their whatever injury or condition they have. Opioids are not the only drugs destroying lives of people around us, but also drugs such as Adderall and Ritilin being prescribed to people who supposedely have ADHD and ADD. The reasons why doctors could possibly be following the patterns of their fellow co-workers is speculated to be due to a large influence of ideas in a local social network known as small area variation, which basically refers to the fact that doctors in similar communities make treatment decisions simply based on the habits and practices of those in their immediate vicinity. These studies suggest that physician behavior is therefore influenced by social signals and not always governed by evidence, best practice, or guidelines. Its highly likely that patterns of both antibiotic and opioid prescription are similarly subject to this same kind of social network effect (Gorman). There needs to be some form of variation in opinion for these doctors to make a substantial impact in their community and do their jobs the correct way. If the world is full of doctors who are insane, there would not be any change in it. We live in the age of technological advancements and where we have access to any particular piece of information in the world at our fingertips, but yet many of us solely look to the authoritarians for their guidance and not at the abundance of resources at our expense. The term mentally ill has been redefined to fit the perception of those who have the right to diagnose individuals as mentally ill. Authoritarians, by definition, demand unquestioning obedience, and so any resistance to their diagnosis and treatment created enormous anxiety for authoritarian mental health professionals feeling out of control, labeling them noncompliant with treatment, increased the severity of their diagnosis and jacked up their medications (Levine). When society attempts to address these issues and question authority, they are treated as enemies of the state and cannot express the truth or even assist families that just want to be cared for and not treated as lab rats. The main issues that we need to be addressing are the roots of the problems these people are having trouble dealing with, not just giving drugs to temporarily suppress them. If society is full of authoritarians, then freedom will be exempt from our vocabulary as well as the future Einsteins and Martin Luther King Jr.s. A highly controversial topic that has already been studied, that has been in denial by pharmaceutical practicioners is the debate on whether or not ADHD medications cause long-term side effects that can be detrimental to overall health. Using logic, we know that every single man made drug affects us negatively some way, shape, or form. The damage may be minute depending on the drug and its purpose, but it will alter the chemistry in our brain forever. There have been various studies on numerous ADHD medications, one being methylphenidate, which is otherwise known as Ritalin which is commonly recommended to children with ADHD. One study states that 1% of children on the medication has had adverse events rated as serious included psychotic symptoms, cardiac arrhythmia, and death. Storeb and the other researchers noted the high prevalence of other side effects as well, such as insomnia and appetite suppression, which occurred in more than half of the children taking the drug (Simons). This study alone should strike fear in the minds of every parent who is fully aware that their child is being medicated with such medication. This places a dark overtone as to what these medications are capable of doing as well as how they can change the life of an innocent child who is unaware of the true reason as to why he is on such medications in the first place. According to the authors: We found that studies funded by pharmaceutical companies had a much lower proportion of both serious and non-serious adverse events. This is worrying, as it shows that adverse events are underestimated in industry-sponsored studies, con? ¬?rming ? ¬?ndings from previous systematic reviews (Simons). Of course we would see a large scale coverup on the studies done by the pharmaceutical companies themselves because they simply want to make a quick buck by having it being prescribed to children. Money equals power and if they have the power to hush the truth from being spread by these many whis tle blowers, then they will do so without remorse because they are gaining an average of $515 billion per year. Some of the side effects that are caused due to taking prescribed ADHD, ADD, and medications for depression are not only affecting the individual taking them themselves, but the people around them as well. Yes we may see the child who is having an adverse side effect from such medications which may have a parent make a cry for help for seeing their child suffer, but there are other circumstances in which the child and or adolescent may affect the world around them. On February 5, 2010, in Huntsville Alabama, a student named Hammad Memon who was only 15 years old, shot and killed another middle school student while being treated with anti-depressants and ADHD medication for years prior to the incident. In January 19, 2007, a teenage named John Odgren stabbed a student in his highschool in the boys bathroom with a kitchen knife to death. His father while in court gave evidence that his son was being prescribed Ritalin. These are just a small percentage of horrific stories that have occ urred within the past 20 years alone. In an article on antidepressants, In a study of thirty-one drugs that are disproportionately linked to reports of violence toward others, five of the top ten are antidepressants. These are Prozac, Paxil, Luvox, Effexor and Pristiq. Two other drugs that are for treating ADHD are also in the top ten which means these are being given to children who could then become violent. One could conclude from this study alone that antidepressants cause both suicidal thoughts and violent behavior. This is a prescription for mass shootings(CCHR). We should be more aware of the likelihood of incidents of mass shootings and suicide occuring when people take such medications. Just remember, these doctors are prescribing people a concoction of mind altering drugs that change lives forever. Treating ADHD, ADD, and depression with homeopathic remedies can make a positive impact not only in ones health, but also how they react to their condition. Taking vitamin and mineral supplements such as vitamin B6 and 12, zinc and iron, vitamin C and magnesium can greatly increase productivity, attention span, and increases the production of dopamine in the brain to give pleasure to the more productive. Overall, diet has makes one of the biggest contributions to how someone with ADHD and depression react to everyday life. Eating regularly (yet not constantly snacking) helps to control blood sugar. This helps to avoid focus and attention issues, irritability, and low physical energy that come with unstable blood sugar levelsSome ADHD characteristics make eating regularly challenging. For example, hyper-focusing might mean you forget to eat because you are so engrossed in your activity. Tasks like meal planning and grocery shopping can be difficult. In addition, ADHD medication can suppress your appetite (Sinfield). If an individual who has been diagnosed with ADHD and is prescribed medications and has great expectations that the medication will solve their attention span and hyperactivity problems, yet eats processed, man made, genetically modified foods all day everyday for many years, that person will never get off the medication and will most likely be recommended to take other medications for help larger problems they are creating for themselves. If someone else decides to take the self medication route by not taking any medications prescribed to them by doctors and they eat live foods, nutrient rich and antioxidant based superfoods, regularly gets excersise and has a good sleep/wake cycle, then i am positive that that person will never need to take prescribed medications a day in their life because they are positively impacting their future health by being aware of their circumstances and everything they do with and put th eir body through. The DSM 5 criteria that is used to diagnose someone with ADHD can probably be used to diagnose every single person in the United States alone with ADHD. Everyone has their own unique personality and can live life without being supported by a crutch that doctors are offering to supposedely assist people with their everyday lives. Human beings are aware that life is an emotional roller coaster and with highs and lows. Just because someone is going through something in a low part of their life, does not mean that it should define who that individual is as a person. Everyone should live their God given life here on earth with the personality they have developed into without strings being attached to the hands of an ever increasing authoritarian community of elites that assist in governing the lives of the innocent. When we have authoritarians limiting our access to knowledge by dumbing the general population down with such medications, we have a large scale epidemic of pandemonium that r oars through a society full of ostriches. We need to educate people, if they are willing of course, to be more aware about what these pharamacuetical companies are doing to human beings and how they are reshaping and worsening the future we will one day live in.

The Constitutional Right Of Liberty Of Contract, By...

All through time The United States of America and the people running have had the debate regarding â€Å"economic Freedom.† Each President of the United States has handled the situation differently and a lot of that has to do with their parties. The Republican Party has believed that the only way to success is by achieving it, therefore their hard work should reflect towards their economic life and freedom. On the other side of things are the beliefs of the Democrats, their views in favor equal opportunity for the working class. Through time Liberal President, Franklin D. Roosevelt and his â€Å"New Deal† as well as Conservative Republican Ronald Regan and his â€Å"Trickle Down Economics†, have both made the biggest economic impacts regarding the debate. The constitutional right of liberty of contract, mandated by the Supreme Court in the early 20th century, is allowing government to be involved with businesses while benefitting the employees as well. Businesses during that time thought they had the constitutional right to mandate hours, money, and all the other major ideas that made their business stay up and running. Although on the other side the government viewed themselves as having the upper hand in determining how a business should be ran. Its major theme was the right of individuals and corporations to enter into contracts with one another. In essence, it was the backbone of capitalism, and caused the economy to thrive and many individuals and corporations to achieve greatShow MoreRelatedThe Theory Of Liberal Ideology1143 Words   |  5 PagesUnited States of America, and touch on a few other areas of political culture. First off liberalism; liberalism is a way of political worldview by the ideas of liberty and equality. Alt hough in a certain time in our history equality was somewhat of a lie. Slavery, racism, and feminism prove that not every single person on the planet had equal rights. 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American Civil Rights Movement THE BLACKS 1865 and 1870 - Three Constitutional amendments: The Thirteenth Amendment abolished slavery, the Fourteenth Amendment gave blacks the rights of citizenship, and The Fifteenth Amendment gave them the right to vote. Until the modern civil rights movement (1950s) blacks were denied access to public places such as restaurants, hotels, theaters, and schools. There were separate facilities marked colored only, which was sanctioned by the courts. 1896

The Woods Essay - 908 Words

I am sitting in the passenger side as my dad is driving, and we are on our way to my grandpas land which is located about 25 minutes east of Dubuque. First thing we do when we get there is to finish putting on our coats, and then to grab our bows out of the back, then I close my door softly. Walking through the open field I have dead weeds and tall grass crunching under my boots, and at the end of the field we reach a barbed wire fence that we crawl under. Then we cross under a bunch of pine trees and go about 30 yards into the woods to where my tree stand sits. Then my dad tells me good luck and he heads down into the gully where his stand is located. So I then climb the 12 foot ladder and sit on the seat and put on my safety belt and†¦show more content†¦The only occasional sounds that are heard are a car driving down the gravel road, dead leaves being blown around, or the wind howling in the trees. Being out in the peaceful woods is also meaningful to me because it gives me time to relax and think about events in my life, and to think about my future. Being out there is relaxing because I am by myself sitting or standing without a care in the world at the time. Being it me against the deer, it gives me a sense that I can outsmart the animals senses and be able to get a chance to shoot it. Since it is away from the noise of the city and my job, it gives me a sense that I am in charge and not being bossed around by anyone else. nbsp; The main reason that hunting and being out in the woods is meaningful to me is because it gives me quality time to spend with my father. This time is precious to me because, he works Tuesday through Saturday (three until midnight), so I dont have a whole lot of time to see him except for when I work on the same day he does. The only time we get to talk during work does not amount to much either because we are both always busy. 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Essay on Online Shopping Is A Daily Habit Of Most Essay Example For Students

Essay on Online Shopping Is A Daily Habit Of Most Essay Online ShoppingIn 2017, it is estimated that three hundred seventy billion dollars will be spent on online shopping. Online shopping has become a daily habit of most. Many people from young to old, shop for different products such as Christmas to birthday or home decorating items to even buying a home. In this day and age it is so easy to surf the Internet, making online shopping fast and convenient. Shopping online has many different aspects as far as the advantages, who is doing the most of online shopping, what to do if you get â€Å"stiffed†, how tracking numbers work, security issues, and last but not least, the potential harm of buying online. First, the advantages of online shopping starts with time saving. I know a lot of people, including my mom, shop because it is so much faster and she runs multiple businesses that take up her time, which doesn’t allow her to actually shop. Many individuals don’t want to waste gas or energy clawing their way through crowds at malls or shopping centers. Another benefit is being able to compare prices as quickly as moving your mouse. Anyone can look at many different websites and be able to see which company has products that are cheaper. The availability of online shopping for products is also incredible. I know that when I show up to stores wanting a certain thing or item and then finding out they are out of stock and won’t get any more for another couple weeks it is very frustrating. Online, a person is allowed to see when the shipment will arrive and can play on getting the item a certain date. Another positive idea about shopping online is that lines are not a worry. I personally hate waiting in lines. For example, black Friday shopping is my moms biggest time for Christmas shopping b. . make sure that the company they are giving money to is not fake. Lastly, many people might ask what is the harm in buying online. You cannot really see or feel they exact thing being purchased on might say. Your items may be broken or incorrect when the buyer has the package delivered to them. If the merchandise is wrong, the person who bought it might have to drive to return it or pay for it to be shipped back. There is also a great chance of online fraud if the company or website is not reliable. There are many disadvantages of online shopping, a buyer must know the risks they take when buying online. In conclusion, I feel that online shopping isn’t all bad and there is a smart way to do it. Online shopping makes life easier for a lot of people and helps companies increase their sales. Overall, online shopping has its perks and defeats just like anything else.

The Conveniences of Modern Technology Essay Example

The Conveniences of Modern Technology Essay It seems that since technology becomes prevailing in modern life, people can’t manage anything without it. It’s helpful in daily life, but there are many surveys starting to focus on the dark side of technology. Even when it comes to the topic of children’s creativity, technology plays a negative role as well. In my opinion, it’s reasonable to view technology in a more critical way when almost all people are overwhelmed by its fantasy. Generally speaking, technology brings convenience into people’s life. But, such convenience sometimes does impact everything involved in human life to be easier. The easiness in some aspects are welcome, but if people, especially children, are used to thinking in an easier way, a disaster may occur. In the past, children played in a relatively natural and physical world. They came across various ‘stuff’ which stimulated their curiosity even the desire of exploration. Then they analysed and concluded everything that they thought were similar. And finally they found something marvellous which enlightened their perspectives. In some of these cases, some of them even created new ideas which changed traditional concepts. However, nowadays, children avoid opportunities to approach the realistic world. It seems that everything can be solved by technology. They use smartphones to send information; GPS to look for a location; Internet to find solutions without rigorous th inking. They are accustomed to thinking easily with the help of technology. This is the first disaster. We will write a custom essay sample on The Conveniences of Modern Technology specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on The Conveniences of Modern Technology specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on The Conveniences of Modern Technology specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Secondly, technology occupies too much time of children. They play computer games to kill time and enjoy chatting on the Internet. Even though there are always campaigns to prevent children from addiction, they still spend much time in front of the computer. No time leaving computers means no time spending on thinking. If they don’t have time to think about what they have already experienced, what creative ideas can be expe