Genetically modified food Essay Example for Free

Genetically modified food Essay GMO foods are such an embedded part of our food system these days, but it’s not difficult to think back to a time when food was simpler and healthier. How did we get to the point that genetically modified organisms infiltrate so much of what we eat? Genetically modified foods (or GM foods) are foods produced from organisms that have had specific changes introduced into their DNA using the methods of genetic engineering. These techniques have allowed for the introduction of new crop traits as well as a far greater control over a foods genetic structure. The introduction of genetically modified food has created both benefits and conflicts among people. The idea of producing food with desirable qualities paved the way for the development of genetically modified food worldwide. Scientists were able to isolate genes with favourable traits and insert them in crops to produce food that can resist drought, insects, pesticides and even is more nutritious. It started by developing a tomato with a longer shelf life in 1994 called Flavr Savr. But then, it was found that consumption of this engineered tomato caused stomach lesions in rats, thus, raising issues about the safety of genetically modified food in general. Since then, the debate raise on the disadvantages of consumption of genetically modified food. Below are just some examples of the long list of disadvantages of such practice; 1. The safety of such products is not verified yet, in fact, we are the lab rats to test the safety of such technology. This is sad but true. In fact, genetically engineered food is being consumed daily with no thorough research of its potential threats on human health. 2. Genetically modified ingredients can cause cancer. A consultant histopathologest at Aberdeen Royal Infirmary, Dr Stanley Ewen, raised the concern that food and water contaminated with genetically engineered material could increase the growth of malignant tumours upon contact with humans. Later, other studies suggested a link between engineered food and cancer.

Advantages Of Internal Combustion Engines Engineering Essay

Advantages Of Internal Combustion Engines Engineering Essay The most widely used heat engine is the internal combustion engine. The advantages that it has over gas turbines have seen its widespread usage in passenger car applications. [1] All the components of internal combustion engines work at an average temperature which is below the maximum temperature of the working fluid in the working cycle. This is because the high temperature of the working fluid in the cycle persists only for a very small fraction of the cycle time. As a result, fluids with high working temperatures can be used to increase thermal efficiency at moderate maximum working pressures. Weight to power ratio is less than that of steam turbine and gas turbines. It is therefore possible to develop reciprocating IC engines of very small power output with reasonable thermal efficiency and cost. Higher brake thermal efficiency can be obtained as only a small fraction of heat energy of the fuel is dissipated to the cooling system. Initial cost is low. Materials used in the manufacture of gas turbines must be strong and heat resistant in order to sustain the heat generated. Machining operations required for gas turbines construction are also more complex. Reciprocating IC engines are more efficient at idle speeds than gas turbines in terms of fuel consumption at idling. Gas turbines have delayed responses to different power requirements changes. Gas turbines must be removed for overhaul and servicing, which is usually not the case in internal combustion engines. Gas turbines require more air than IC engines for its normal operation. It also consumes more fuel whenever the load fluctuates, which is common in the domestic usage. All these explain why passenger cars do not use gas turbine engines, but use internal combustion engines instead. Question 2 Define the following parameters and give typical values for spark-ignition and compression ignition IC engines: Specific fuel consumption, Specific fuel consumption (SFC) is the fuel flow rate per unit power output []. It measures how efficiency of an engine in using the fuel to produce useful work. The equation for the specific fuel consumption is: Where: Ke= specific fuel consumption K: Fuel Consumption, kg/s Pe=Useful work per cycle, i = 0.5 for 4ÃŽ, 1 for 2ÃŽ ne=real efficiency HÃŽÂ ± =Heat of Combustion = 42.000 KJ/Kg Low values of SFC are obviously desirable. For SI engines typical values of brake specific fuel consumption are about 270 g/kWh. Range (345 285 g/kWh) For CI engines, values are lower and in large engines can go below 200 g/kWh. Range (285 190 g/kWh) [2] Mean effective pressure, Relative engine performance measure is obtained by dividing the work per cycle by the cylinder volume displaced per cycle. The parameter so obtained has units of force per unit area and is called the mean effective pressure (mep). Where: W=Indicated Work: Vh=Piston Displacement (cylinder) Volume (cc, cm3, lt) H=Length TDC Length BDC For, Naturally aspirated spark ignition engines, maximum values are in the range 850 to 1050 kPa at the engine speed where maximum torque is obtained (about 3000 rev/min). Turbocharged automotive spark-ignition engines the maximum bmep is in the 1250 to 1700 kPa range. Naturally aspirated four-stroke diesels, the maximum bmep is in the 700 to 900 kPa range Turbocharged four-stroke diesel maximum bmep values are typically in the range 1000 to 1200 kPa Turbocharged aftercooled engines this can rise to 1400 kPa Two-stroke cycle diesels have comparable performance to four-stroke cycle engines. Large low-speed two-stroke cycle engines can achieve bmep values of about 1600 kPa. [2] Power-torque relation as function of engine rpm, Engine torque is measured using a dynamometer. The engine is clamped and the output shaft is connected to the dynamometer rotor. The rotor is coupled electromagnetically, hydraulically, or by mechanical friction to a stator, which is supported in low friction bearings. The stator is balanced keeping the rotor stationary. The torque exerted on the stator with the rotor turning is measured by balancing the stator with weights, springs, or pneumatic means. Fig.1 Brake dynamometer- engine torque test [2] Torque is a measure of an engines ability to do work; and power is the rate at which work is done. The value of engine power measured as described above is called brake power Pb. This power is the usable power delivered by the engine to the load-in this case, a brake. Fig.2 Engine power, torque vs. speed plot [3] Correlation between measured force and engine torque: Measured power: (1 PS = 0.736 kW) Conversion between different units may be necessary for power, torque, or angular speed. For example, if rotational speed (revolutions per time) is used in place of angular speed (radians per time), a factor of 2à Ã¢â€š ¬ radians per revolution have to be multiplied. Dividing on the left by 60 seconds per minute and by 1000 watts per kilowatt gives us the following. mbox{power (kW)} = frac{ mbox{torque (N}cdotmbox{m)} times 2 pi times mbox{rotational speed (rpm)}} {60,000} Volumetric efficiency Volumetric efficiency is the ratio of the mass inside the engine cylinder to the mass of air of the displacement volume at atmospheric conditions. It measures the effectiveness of an engines induction process. Volumetric efficiency is used for four-stroke cycle engines which have a distinct induction process and not for two stroke engines. Where pai is the inlet air density Alternatively volumetric efficiency can also be defined as, Indicative values: 4ÃŽ-Otto: 0.7 0.9 2ÃŽ-Otto: 0.5 0.7 Typical maximum values of ÃŽÂ ·v for naturally aspirated engines are in the range 80 to 90 percent. The volumetric efficiency for diesels is somewhat higher than for SI engines. [2] Engine real efficiency as function of engine power, fuel consumption and fuel calorific value The real engine efficiency of an engine can be found out using the relation Where, ne=real efficiency nth= theoretical thermodynamic efficiency ng=quality coefficient (0.4-0.7 Otto; 0.6-0.8 Diesel) nm=mechanical efficiency (0.8) ni=actual efficiency (nth.ng=Pi/Q) K= fuel consumption Kg/s HÃŽÂ ± =Heat of Combustion = 42.000 KJ/Kg Question 3 Describe with simple terms the main air flow path developing inside the cylinder of IC engines relative to the piston motion; make a simple schematic to indicate them. Laser Doppler Velocimetry (LDV) helps us to visualise the charge motion within the cylinder with the help of optically transparent research engines. Computational Fluid Dynamics (CFD) can help in validating the average flow field in the cylinder but the process is expensive. One such CFD software is KIVA-4v, which helps to predict the air charge motion. Swirl flow Swirl is defined as the micro mass rotational motion of charge within the cylinder. It is generated by constructing the intake system to give a tangential component to the intake flow as it enters the cylinder. This is done by shaping and contouring the intake manifold, valve ports, and sometimes even the piston face. Swirl enhances the mixing of air and fuel to give a homogeneous mixture in a short time in modern high-speed engines. It is also responsible for very rapid spreading of flame front during the combustion. Fig.3 Swirl flow in the engine cylinder [3] Swirl flow can be generated by changing the geometry of the inlet port Fig.4 Geometry of inlet port affecting swirl flow [3] (a) Deflector wall (b) directed (c) shallow ramp helical (d) steep ramp helical Similarly inlet valve approach geometry can also generate swirl flow by producing net in-cylinder angular momentum of the charge. Fig.5 Inlet valve geometry affecting swirl flow [2] Squish flow When the piston approaches TDC at the end of the compression stroke, the volume around the outer edges of the combustion chamber reduces drastically. New combustion chamber designs have the clearance volume near the centerline of the cylinder. As the piston approaches TDC, the gas mixture occupying the volume at the outer radius of the cylinder is forced radially inward as this outer volume is reduced to near zero. This radial inward motion of the gas mixture is called squish. It adds to other mass motions within the cylinder to mix the air and fuel, and quickly spreads the flame front. Maximum squish velocity usually occurs at about 10 °bTDC. During combustion, the expansion stroke begins and the volume of the combustion chamber increases. As the piston moves away from TDC, the burning gases are propelled radially outward to fill the now-increasing outer volume along the cylinder walls. This reverse squish helps to spread the flame front during the latter part of combustion Piston motion influences squish as in the case of wedge shaped and bowl-in combustion chambers. Fig.6 Piston motion generating squish [2] (a) Wedge shaped SI combustion chamber (b) bowl-in-piston DI Diesel combustion chamber Tumble As the piston nears TDC, squish motion generates a secondary rotational flow called tumble. This rotation occurs about a circumferential axis near the outer edge of the piston bowl Fig.7Tumble- result of piston motion and squish [3] Turbulence Due to the high velocities involved, all flows into, out of, and within engine cylinders are turbulent flows. The exception to this is those flows in the corners and small crevices of the combustion chamber where the close proximity of the walls dampens out turbulence. As a result of turbulence, thermodynamic transfer rates within an engine are increased by an order of magnitude. Heat transfer, evaporation, mixing, and combustion rates all increase. As engine speed increases, flow rates increase, with a corresponding increase in swirl, squish, and turbulence. This increases the real-time rate of fuel evaporation, mixing of the fuel vapor and air, and combustion. Intake turbulent mixture flow Turbulence superimposed on mixture swirl Fig.8 Turbulence of the charge within cylinder [4] Question 4 The Figure below shows a conceptual model of a quasi-steady Diesel combustion plume, as presented by Dec et al in 1997. Indicate the following areas shown on this schematic: liquid fuel , rich vapour fuel-air mixture , fuel-rich premixed flame, initial soot formation , diffusion flame boundary , thermal NO production zone , soot oxidation zone , 25398f1.jpg Fig.9 Quasi-steady Diesel combustion plume [5] The above figure describes the formation and features of a quasi-steady diesel fuel jet. This model is applicable to large bore, quiescent chamber combustion or a free fuel jet without wall interactions. At the point of fuel injection, fuel penetrates into the combustion chamber and air which is at a high temperature due to end of compression stroke begins to mix with the spray. Fuel absorbs energy from the hot air and evaporates. This process continues until a point where no liquid fuel is present. The point at which this occurs is called the liquid length. This liquid length reduces after the start of combustion but thereafter remains constant until the end of injection. Beyond the liquid length, the rich premixed fuel and air are still heated by the surroundings until they start to react in the rich premixed zone. The products of rich combustion continue downstream and diffuse and mix radially outward until reaching the surrounding cylinder gases. At a location where the rich prod ucts and cylinder gases mix to produce a stoichiometric mixture, a diffusion flame is produced. The diffusion flame surrounds the jet in a thin turbulent sheet, which extends upstream towards the nozzle. The axial distance from the nozzle exit to the diffusion flame is the lift-off length. The lift-off length controls the amount of oxygen mixed into the fuel jet and therefore the stoichiometry. Soot is burned out and NOX is produced on the outside of the diffusion flame, where temperatures are high and oxygen and nitrogen are abundant. Question 5 What are the main requirements of the fuel injection system for a direct injection engine? In recent years, significant progress has been made in the development of advanced computer-controlled fuel injection systems, which has had much to do with the research and development activities related to Direct Injected engines being expanded. [6]The main requirements of the fuel injection system for a direct injection engine are: Well atomised fuel spray independent of chamber pressure conditions Injection during the compression stroke against pressures up to 20bar Injection during the intake stroke against atmospheric pressures with stoichiometric homogeneous mixture To have uniform distribution of fuel in a multi cylinder engine To improve breathing capacity of an engine i.e. volumetric efficiency To reduce or eliminate detonation To prevent fuel loss in the form of scavenging in the case of two stroke engines. For an efficient combustion of a stratified mixture, a stable and compact spray geometry is necessary Injection pressure has been determined to be very important for obtaining both effective spray atomization and the required level of spray penetration. Accurate fuel metering (generally a +2% band over the linear flow range); Desirable fuel mass distribution pattern for the application; Minimal spray skew for both sac and main sprays; Good spray axisymmetry over the operating range; Minimal drippage and zero fuel leakage, particularly for cold operation; Small sac volume; Good low-end linearity between the dynamic flow and the fuel pulse width; Small pulse-to-pulse variation in fuel quantity and spray characteristics; Minimal variation in the above parameters from unit to unit. Question 6 Describe the injection process requirements for direct injection Diesel engines and the evolution of the fuel injection equipment over the last few decades. The functional requirements of the fuel injection system are as follows Accurate fuel metering per engine working cycle Injection timing to ensure maximum power, good fuel economy and low emissions Obtain the desirable heat release pattern by control of injection rate Atomisation of the fuel Proper spray pattern to ensure better mixing of fuel and air Uniform distribution of fuel droplets in the combustion chamber Supply equal quantities of fuel to all cylinders, in the case of multi cylinder engines Eliminate dripping of fuel droplets into the combustion chamber by eliminating injection lag between start and end of injection Evolution of fuel injection equipment: In-line pump Fig.10 Layout of In-line fuel injection pump [7] Though in-line pumps are primitive injection systems, they are still in use among heavy duty marine engines. Individual fuel pumps fuel each of the injectors Engine operational speed has a major influence on the fuel injection pressures As a result, there is a hydraulic delay between the pressure increase and the start of injection Fuel flows through high pressure connecting pipes Fuel injection pressures range from 600 1200 bar Injector with discharging in the combustion chamber (the nozzle with one or more holes) Distributor type pumps These are still used in a number of engines Though it started as mechanically operated, now electronic control modifications have been made It has a mechanism which controls the spill valve responsible for cutting off the high pressure generated inside the pumping chamber, and thus, responsible for the termination of injection One pumping chamber delivers high pressure to all the injectors of the engine Pressure depends on engine speed, so a hydraulic delay exists between the pressure generation and start of injection Relatively low injection pressures (up to 1200bar) Fig.11 Distributor type pump (Lucas CAV) [7] Unit injectors Consists of the pump and the injector integrated into one body, which does not require a high pressure connection pipe High fuel pressure is generated close to the nozzle exit, which can be upto 2500 bar. These gave accurate control over injection Each cylinder has its own individual system High pressure developed depends of the engine rpm and the load. Fig.12 General Layout of Unit injector [7] [6]Delphi Diesel Systems electronic unit injectors (EUI fig13.) control the quantity and the timing of injection electronically through a solenoid actuator. The solenoid can respond very quickly (injection periods are of the order 1 ms), to control very high injection pressures (up to 1600 bar or so). The solenoid controls a spill valve, which in turn controls the injection process. The pumping element is operated directly from a camshaft (or indirectly via a rocker), and the whole assembly is contained within the cylinder head. Fig.13 Electronic Unit injector (Lucas EUI system) [7] [6]An alternative approach to the EUI is the Caterpillar Hydraulic Electronic Unit Injector (HEUI, also supplied by other manufacturers). HEUI uses a hydraulic pressure intensifier system with a 7: 1 pressure ratio to generate the injection pressures. The hydraulic pressure is generated by pumping engine lubricant to a controllable high pressure. Similar to CR injection systems, there is control of the injection pressure. The HEUI uses a two-stage valve to control the oil pressure, and this is able to control the rate at which the fuel pressure rises, thereby controlling the rate of injection, because a lower injection rate can help control NOx emissions. Common Rail fuel injection systems One of the last improvements to the fuel injection system is the Common Rail System that was implemented first by the Fiat Company. Fig.14 Common rail fuel injection system [8] Common rail (CR) fuel injection systems decouple the pressure generation from the injection process and have become popular because of the possibilities offered by electronic control. The key elements of a CR fuel injection system are as follows: A (controllable) high-pressure pump The fuel rail with a pressure sensor Electronically controlled injectors An engine management system (EMS) The injector is an electro-hydraulic device, in which a control valve determines whether or not the injector needle lifts from its seat. The engine management system can divide the injection process into four phases: two pilot injections, main injection, and post-injection (for supplying a controlled quantity of hydrocarbons as a reducing agent for NOx catalysts). Common rail injection also enables a high output to be achieved at a comparatively low engine speed Fuel injectors Fig.15 Types of nozzles used in Diesel fuel injectors [1]

Henry Flemming and then Red Badge of Courage Essay example -- essays r

Fear, worry, anxiety, curiosity, distress, nervousness; all emotions of a young, naà ¯ve soldier entering war for the first time. To the reader, this is exactly what Henry Fleming represents. Because Crane never tells us what he looks like, just how old he is, or exactly where he comes from, and usually refers to him as â€Å"the youth† (Crane, 12) or â€Å"the young soldier† (Crane, 14), Henry could be any young many experiencing war for the first time. Throughout the novel The Red Badge of Courage, Henry Fleming goes through many psychological chances, each having a distinct impact on the novel. These changes can be put into three stages; before, during, and after the war. Due to the ambiguity surrounding the character of Henry Fleming, the novel is not just a tale of Henry’s firsthand experiences, but a portrayal of the thoughts, feelings, fears, and development of any young soldier entering any war at any time. Although Crane leaves much to the imagination when it comes to Henry Fleming, he does however reveal quite a bit about his early life. It becomes apparent that as a young boy, Henry grew up on a farm in New York (Crane, 17). Henry was raised by his loving mother after the tragic death of his father (Crane, 15). The occupants of the farm consist of Henry and his mother, who together tackle the necessary workload to maintain the farm and keep it in good condition (Crane, 17). The life Henry has led up to the point when he enters the draft, has been somewhat quiet, protected and sheltered (Crane, 11). This â€Å"wrapped in cotton wool† (Crane, 21) lifestyle could party contribute to Henry’s naà ¯vely distorted views of war and later lead to his misfortune (Weisberger, 22). Crane portrays Henry as a typical young American brought up in the nineteenth century (Weisberger, 22). He has been taught to associate manhood with courage, to dream of the glories of warfare, and to be instinctively patriotic (Breslin, 2). As a result, when the civil war breaks out, Henry volunteers to join the Union Army (Gibson, 61). Immediately, his mother disapproves of his decision, claiming that he would be much more useful on the farm (Crane, 23). At this point in the novel Henry is not mature enough to recognize the validity of his mothers statement (Gibson, 63). "Yer jest one little feller amongst a hull lot of others† (Cra... ...Library, 1993. Delbanco, Andrew. The American Stephen Crane: The Context of The Red Badge of Courage. New Essays on The Red Badge of Courage. New York: Cambridge Univ. Press, 1986. Gibson, Donald B. The Fiction of Stephen Crane. Southern Illinois University Press, 1968. 60-89 Hungerford, Harold. R. The Factual Framework of The Red Badge of Courage. American Literature (34: 4) January, 1963. Mitchell, Lee Clark. New Essays on The Red Badge of Courage. New York: Cambridge U P, 1986 Weisberger, Bernard, "The Red Badge of Courage," in Twelve Original Essays on Great American Novels, edited by Charles Shapiro, Wayne State University Press, 1958, pp. 120-21. EXPLORING Novels. Online Edition. Gale, 2003. Reproduced in Student Resource Center. Detroit: Gale, 2004. http://galenet.galegroup.com/servlet/SRC. Weiss, Daniel. Psychology and the Red Badge of Courage. Stephen Crane‘s The Red Badge of Courage. Bloom, Harold. New York: Chelsea House Publishers, 1987. Henry Flemming and then Red Badge of Courage Essay example -- essays r Fear, worry, anxiety, curiosity, distress, nervousness; all emotions of a young, naà ¯ve soldier entering war for the first time. To the reader, this is exactly what Henry Fleming represents. Because Crane never tells us what he looks like, just how old he is, or exactly where he comes from, and usually refers to him as â€Å"the youth† (Crane, 12) or â€Å"the young soldier† (Crane, 14), Henry could be any young many experiencing war for the first time. Throughout the novel The Red Badge of Courage, Henry Fleming goes through many psychological chances, each having a distinct impact on the novel. These changes can be put into three stages; before, during, and after the war. Due to the ambiguity surrounding the character of Henry Fleming, the novel is not just a tale of Henry’s firsthand experiences, but a portrayal of the thoughts, feelings, fears, and development of any young soldier entering any war at any time. Although Crane leaves much to the imagination when it comes to Henry Fleming, he does however reveal quite a bit about his early life. It becomes apparent that as a young boy, Henry grew up on a farm in New York (Crane, 17). Henry was raised by his loving mother after the tragic death of his father (Crane, 15). The occupants of the farm consist of Henry and his mother, who together tackle the necessary workload to maintain the farm and keep it in good condition (Crane, 17). The life Henry has led up to the point when he enters the draft, has been somewhat quiet, protected and sheltered (Crane, 11). This â€Å"wrapped in cotton wool† (Crane, 21) lifestyle could party contribute to Henry’s naà ¯vely distorted views of war and later lead to his misfortune (Weisberger, 22). Crane portrays Henry as a typical young American brought up in the nineteenth century (Weisberger, 22). He has been taught to associate manhood with courage, to dream of the glories of warfare, and to be instinctively patriotic (Breslin, 2). As a result, when the civil war breaks out, Henry volunteers to join the Union Army (Gibson, 61). Immediately, his mother disapproves of his decision, claiming that he would be much more useful on the farm (Crane, 23). At this point in the novel Henry is not mature enough to recognize the validity of his mothers statement (Gibson, 63). "Yer jest one little feller amongst a hull lot of others† (Cra... ...Library, 1993. Delbanco, Andrew. The American Stephen Crane: The Context of The Red Badge of Courage. New Essays on The Red Badge of Courage. New York: Cambridge Univ. Press, 1986. Gibson, Donald B. The Fiction of Stephen Crane. Southern Illinois University Press, 1968. 60-89 Hungerford, Harold. R. The Factual Framework of The Red Badge of Courage. American Literature (34: 4) January, 1963. Mitchell, Lee Clark. New Essays on The Red Badge of Courage. New York: Cambridge U P, 1986 Weisberger, Bernard, "The Red Badge of Courage," in Twelve Original Essays on Great American Novels, edited by Charles Shapiro, Wayne State University Press, 1958, pp. 120-21. EXPLORING Novels. Online Edition. Gale, 2003. Reproduced in Student Resource Center. Detroit: Gale, 2004. http://galenet.galegroup.com/servlet/SRC. Weiss, Daniel. Psychology and the Red Badge of Courage. Stephen Crane‘s The Red Badge of Courage. Bloom, Harold. New York: Chelsea House Publishers, 1987.

The Downfall of Lady Macbeth :: Free Macbeth Essays

The Downfall of Lady Macbeth   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Macbeth is a play full of magic, mystery, and murder.   The variety of plots, as well as the interesting characters, force the reader to pay full attention at all times.   Unfortunately, one of these characters is a victim of her own imagination. Although Lady Macbeth adds much positive flavour to the play, her character is revealed through her aggressive attitude with her husband, her inhumane disregard for life, and her guilty conscience.      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Lady Macbeth is very assertive when dealing with her husband's hesitations about murdering Duncan:      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   "O never shall sun that morrow see!   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Your face... is as a book where men   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   May read strange matters.   To beguile the time,   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Look like the time; bear welcome in your eye,   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Your hand, your tongue: look like the innocent flower   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   But be the serpent under't."    This urging causes Macbeth to possess Å’black and deep desires', which lead him to   murder the king.   She takes it upon herself to pressure him and therefore, her bold character is revealed.   Macbeth's intentions would have been less serious if his wife was not more anxious than he was.   She, more than her husband, is to blame for the death of King Duncan, due to her relentless pursuit of power and authority.      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Lady Macbeth is a heartless fiend with an savage disregard for life. This is evident in the manner in which she downplays the murder of Duncan to her husband:      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   "A little water clears us of this deed;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   How easy is it, then!   Your constancy   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Hath left you unattended...   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Get on your night-gown, lest occasion call us,   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   And show us to be watchers.   Be not lost   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   So poorly in your thoughts."    She tries to make Macbeth believe that committing the murder was not a vicious deed and that washing their hands will wash away all the guilt.   Macbeth exclaims that "all Neptune's ocean" will not wash the blood from his hands. Lady Macbeth appears at this point to be a ruthless killer working on behalf of the prince of darkness, which solidifies her character and gives the audience new insights to her psychological state.      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   The audience is lead to believe that Lady Macbeth will never feel any guilt concerning the murder, but her guilty conscience is displayed near the end of the play. She begins to sleepwalk and relive the murder in her mind:      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   "Out, damned spot! out, I say!   One; two; why, then   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Å’tis time to do't.   Hell is murky!   Fie, my lord--fie!   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   a soldier, and afeard?

The Irish Essay -- essays research papers fc

  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ireland has a great history of war, famine, despair, and hardship. Throughout the years the Irish have come from the lowest of lows to the highest of highs. In this paper I will give a history of the Irish people before coming to America, what it was coming here, how they were welcomed to their new home, and how they are faring now. I will also expose many of the stereotypes that the Irish have pinned to them and the reason that they are there.   Ã‚  Ã‚  Ã‚  Ã‚  In the early 1800's, the Irish had great success in the potato industry due to the high prices for agricultural products because of the war with England. Soon though, prices began to fall and so did productivity. For that reason, the owners of the farm land turned there plots into grazing areas. There was an addition problem though, what would happen to the hundreds of other farmers that worked the land? One popular solution for most â€Å"landlords†, as they were called, was to evict all the tenants, whether they were paid up for rent or not. Then they would destroy their homes so that they could not return.(No author 1).   Ã‚  Ã‚  Ã‚  Ã‚  The now homeless people turned to secret organizations to retaliate against the people that they once depended on to live their lives. Some names of these groups were Rightboys, Thrashers, Ribbonmen, and Whitefoots.(No author 1). When these vigilantes were caught, their punishments were severe. Something as simple as stealing a piece of bread could land you a multiple year sentence in prison. To add insult to injury, the prisons that these people were sent to was in Australia, many miles away from there homes. It was thought that things for the Irish could not get any worse, but in 1845 that is just what happened.   Ã‚  Ã‚  Ã‚  Ã‚  The potato was a very significant part of the Irish way of life. It is one of the few foods that a person can survive solely on. Many homes lived exclusively on the potato, they could   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   ... ...e in their new country. Now all we have to do as a society is drop all the foolish stereotypes that most of us still have and let the Irish be the Irish, Whites be the Whites, the Blacks be the Blacks and so on. Who cares where people come from or what has happened in the past? We are in the here and now, no need to look back on things done long ago. Put the past behind and the future in front and I think that America would be better off.   Ã‚  Ã‚  Ã‚  Ã‚   Works Cited Connery, Donald. The Irish   Ã‚  Ã‚  Ã‚  Ã‚  Simon and Schuster. New York, NY. 1968 Kennedy, Robert. The Irish   Ã‚  Ã‚  Ã‚  Ã‚  University of California Press. Berkley and Los Angeles California. 1973 Larson, Audrey. History of Ireland www.humboldt1.com   Ã‚  Ã‚  Ã‚  Ã‚  2-27-2004 McCarthy, Joe. The World Library: Ireland   Ã‚  Ã‚  Ã‚  Ã‚  Time Incorporated. New York, NY. 1964 O Grada, Cormac. Black ‘47 and Beyond   Ã‚  Ã‚  Ã‚  Ã‚  Princeton University Press. Princeton, New Jersey. 1999 No Author. Http://www.humboldt1.com/history/.2-27-2004   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  

Discuss the discovery of the structure of Benzene

Benzene is a chemical compound of the hydro-carbon group. It is a colorless liquid with a characteristic odor and burning taste, formula C6H6. The benzene molecule is a closed ring of six carbon atoms connected by bonds that resonate between single and double bonds; each carbon atom is also bound to a single hydrogen atom. It is insoluble in water, but miscible in all proportions with organic solvents. Benzene itself is an excellent solvent for certain elements, such as sulphur, phosphorus, and iodine; for gums, fats, waxes, and resins; and for most simple organic chemicals.It is one of the most commonly used solvents in the organic chemical laboratory. Benzene melts at 5. 5 ° C (41. 9 ° F), boils at 80. 1 ° C (176. 2 ° F), and has a relative density of 0. 88 at 20 ° C (68 ° F). It is widely regarded as carcinogenic and, if inhaled in large quantities, is poisonous. The vapors are explosive, and the liquid violently flammable. Many compounds, such as nitrobenzene, are obt ained from benzene. Benzene is also used in the manufacture of drugs and in the production of important derivatives, such as aniline and phenol (see Hogben, Lancelot.Science for the Citizen: A Self-Educator Based on the Social Background of Scientific Discovery, 1999). Benzene and its derivatives are included in the important chemical group known as aromatic compounds. II. Discussion Benzene is only slightly soluble in water, but can be mixed in all proportions with acetone, alcohol, ether, or glacial acetic acid. It burns with a smoky flame. The vapor forms an explosive mixture with air, and has been used in parts of the world as a motor fuel.At one time, most benzene was obtained from tars and gases produced during the making of coke for the iron and steel industry. Now, however, much of the world’s supply of benzene is obtained by the refining of petroleum. Moreover, the benzene molecule is believed to be shaped like a ring, rather than like a cube or a chain as are other hydrocarbon molecules. The theory of the benzene ring is an important principle in organic chemistry. The aromatic series of hydrocarbons are compounds containing benzene ring.The theory of the structure of the benzene molecule was first stated by the German chemist August Kekuke in 1865. He suggested that the six carbon atoms of benzene were arranged in a hexagonal ring, with each of the six hydrogen atoms attached to one of the carbon atoms. Since each carbon atom has a valence of 4, alternate carbon atoms share two valence bonds in the benzene ring (see Aftalion, Fred and Benfey,Otto Theodor. A History of the International Chemical Industry, 2000).Pure benzene burns with a smoky flame because of its high carbon content. When mixed with a large proportion of petrol it makes a satisfactory fuel. In Europe benzene mixed with some methylbenzene and other related compounds has long been added to motor fuels. The wisdom of this in the face of benzene's carcinogenic qualities has only r ecently been addressed as a concern. Benzene was discovered in 1825 by the English scientist Michael Faraday, and in 1842 it was made available in large quantities after it was found that coal tar contains benzene.A ton of coal, if coked in a by-product oven, yields about 7. 6 liters (2 gallons) of benzene (see Audrieth, Ludwig Frederick. Salts, Acids, and Bases: Electrolytes Stereochemistry, 2001). Large quantities of benzene are now obtained from petroleum, either by direct extraction from certain types of crude oils or by chemical treatment of petroleum (hydroforming and cyclization). III. Conclusion The structure of the benzene molecule is of the utmost importance to the theory of organic chemistry.The first to formulate the resonating ring structure described above was the German chemist Friedrich August Kekulà © von Stradonitz, in 1865. For various reasons, 20th-century theorists found difficulties with this picture and instead developed a â€Å"molecular orbital† pict ure of electrons orbiting the entire molecule rather than particular carbon atoms. In the 1980s, however, more advanced studies returned to Kekulà ©'s picture, but with the electrons in deformed orbits around their particular atoms.

Plato’s View of Justice in the Republic Essay

Having lived an extraordinarily long life (for his time), with no consistent doctrine of belief, it has become customary to divide Plato’s writings chronologically into three periods, Early, Middle and Late. The Republic, a collection of ten books, is thought to have been written after Phaedo during the ‘middle-period’ of Plato’s life. It is during this period that Plato’s philosophy becomes his own rather than a commentary on Socrates beliefs and sayings. It is important to remember that Plato’s time was an age of constant upheaval and it is this air of upheaval and constant change that led him to focus on his societies’ failings and to put forward a structured society that puts his view of justice into practice. The main theme of The Republic is to define justice and other virtues and to put forward an idea for a Utopian city-state based on his beliefs on justice and virtue to show how these ideals could be implemented. The text takes the form of a dramatised discourse between certain characters of differing backgrounds and beliefs. The use of a dramatised debate is a useful way to demonstrate the way Plato (whose ideas are represented by the character of Socrates) would handle his sceptics. It also serves to show the development of his thought through discussion and to sceptic-proof his argument by foreseeing potential counter arguments. Plato starts demonstrating his definition by taking some popular conceptions of what justice means and whether it is better to live a just life. In book one the debate starts with a statement made by Cephalus, an old, retired self-made manufacturer. Cephalus puts forward the view that as people grow older they become more aware of religious teachings regarding retribution in the afterlife for living an unjust life and therefore monitor they’re own behaviour, in the past and present: ‘And when he finds that the sum of his transgressions is great he will many a time like a child start up in his sleep for fear, and he is filled with dark forebodings.’ He is saying that idea of justice is something that is merely a doctrine enforced by the unproven premise of damnation. If fear of an unproven afterlife is the reasoning for living a just life then the argument for justice is weak and reliant on blind faith. If an individual does not believe in ‘Hades’ or Hell then what stops him from acting unjustly? Continuing on Cephalus states ‘Wealth can do a lot to save from having to cheat or deceive someone against our will and from having to depart for that other place in fear because we owe a sacrifice to a god or money to a person’. By this Cephalus means that by having ample wealth he never had the need to be unjust to anyone. He could afford to appease the Gods with sacrifice and to keep his debts paid. This first presented description of justice is flawed. Socrates gives the following example to prove this: Suppose that a friend when in his right mind has deposited arms with me and he asks for them when he is not in his right mind, ought I to give them back to him? No one would say that I ought or that I should be right in doing so, any more than they would say that I ought always to speak the truth to one who is in his condition.’ Socrates, by Cephalus’s definition just living, was acting in a just way when he returned weapons to a maniacal friend (paying his debts). The modern day equivalent of this scenario is the United Nations returning a previously confiscated nuclear weapon to an insane and potentially violent state in full knowledge that it will be used to wreak havoc (injustice). This demonstrates that Cephalus’s popular description of justice is weak and potentially unjust! Later in book 1, When Socrates criticizes Polemarchus’ idea that man should spite his enemies, Thrasymachus puts his view forward; ‘Since the established rule is surely stronger, anyone who reasons correctly will conclude that the just is the same everywhere, namely the advantage of the  stronger’ . Using this idea Thrasymachus has declared that justice is the preserve of the strong and powerful. Justice is whatever the powerful dictate to the masses. He then goes on to state that it is the duty of the poor to rise up and take what they can from the rich. Socrates refutes all these ideas. He believes that the poor should accept the true justice that is imposed on them by the government. This is an idea that is crucial to the utopia he will later describe. Thrasymachus demonstrates a sophistic belief that injustice is more profitable to the individual than justice. By restating his belief that only the powerful have control over justice and successfully canvassing for a general consensus that rulers are fallible he shows that justice (as administered by the powerful) is ‘harmful to the one who obeys and serves’ . This in itself makes a certain degree of sense since in our own modern times we consistently see examples of ‘justice’ (as administered by the powerful) being non-beneficial to the weak and subservient. The most recently highlighted example would be the recent focus on Taliban-governed Afghanistan. Justice to the population of a Taliban controlled region meant harsh punishments and draconian, puritanical laws. This is what by European standards would be called unjust. If Thrasymachus had stopped his argument at this point then he would have contributed an important element to the definition of justice that we assume in our use of the word today, that which is morally correct. However as Thrasymachus is from a sophistic background (i.e. teacher of economics and rhetoric with especially capitalistic, profit driven motivations) he continues into a less popular (by modern standards) potential consequence of his argument, injustice is more profitable than justice. Through clever debate and reasoning with Thrasymachus, Plato (through his ‘mouthpiece’ character, Socrates) arises at the following conclusion: ‘Apparently, then, injustice has the power, first, to make whatever it arises in-whether it is a city, a family, an army, or anything else-incapable of achieving anything as a unit, because of civil wars and differences it  creates, and second, it makes that unit an enemy to itself and to what is in every way its opposite, namely justice.’ This statement shows the Sophist’s argument to be a contradiction. It is impossible for a belief to be profitable if it simply leads to dissent amongst the parties seeking profit. It is impossible for injustice to serve anyone if it is an enemy to itself. Plato points out that for a collective of individuals to act out injustice and all profit from the act there must originally be some sort of justice present to prevent them all betraying each other, an ‘honour amongst thieves’ of sorts. The argument for injustice does not end with book one and returns briefly early in book two. At the end of book one Plato is no longer refuting suggestions on the nature of justice and is no speaking in a pro-active, positive manner. He begins to start to build his own ideas of justice. He believes justice to be more profitable than injustice describing the comparison like so; ‘a just person is happy and an unjust one is wretched’ . This conclusion is reached in the p receding lines when Thrasymachus to agrees that justice is a virtue of the soul and therefore that a soul cannot perform well if its particular virtue is faulty. There is another important argument that Plato addresses in book two, where Glaucon, the youth, returns to Thrasymachus’s argument with an amendment. Glaucon asserts that it is profitable for the individual to pretend to be just but live their life in an unjust manner. The idea behind this being that the individual can appear to have the virtue of justice to others without having to be burdened with the responsibilities and constraints of living a just life. To consider all of these arguments and how they are presented would take many theses and, although relevant to this essay topic, I must move on to Plato’s own decisions of what justice is and their implementation in his polis due to space and time constraints. Plato has argued that living justly is much more superior to living unjustly because justice breeds happiness and contentment. The next step for Plato, to state and demonstrate his own positive views on justice and why it is ‘profitable’, is to describe a city-state, a polis, which is an ideal Utopia where all citizens live in harmonious eudemonia. By using the macrocosm of  the state he will show how justice can be implemented in the individual. Plato believes in the immortality of the soul (a consequence of nous ) and its division into three parts, which in turn are affected by ordering powers. The three parts of the soul are the spiritual, dedicated to the devotion of honour, the rational, dedicated to reason and logical thought and the appetitive, the basic appetites of the human soul such as sex, acquisitions, praise etc. which must be controlled. This is a fiercely rational and, I would argue, flawed break down of the human character. It takes no account for the emotional aspect of mankind and it is this inhuman and extremely rational view of humanity that would lead to the immediate failure of the polis if it wherever established due to some of the constraints placed on the citizens of the polis as will be seen later on. The virtues (aretai) of the soul that Plato describes in book four are wisdom (sophia), courage (andreia), temperance (sophrosyne) and justice (dikaiosyne). It is this idea of the soul that Plato will use in to socially structure the polis . The aim of this city is to make the soul is happy because all three parts of it are moderated, doing their own jobs and nothing else. This relates to Plato’s view of justice in the following manner. To Plato justice and injustice where to the body what health and disease are in the body. This is a beautiful analogy and is very similar to basic facets of Chinese medicine were disturbance in the mind is viewed as a pivotal cause for ill physical health, one wonders were oriental factors an influence on Plato or vice versa at this time. This correlation of classical Greek and ancient Chinese science is especially apparent in 444d of The Republic when ‘Health is defined as the establishment of an order by nature among the parts of the body; disease as a disturbance of the natural order of rule and subordination among the parts (444d)’ . This reading of Plato by Voeglin makes more sense in the context of the polis, as the disease of injustice is the divisor of peoples and the cause of discontent in society. The polis must be designed in such away that contentment is valued at a premium and corruption and vice made unnecessary and irrelevant. This has parallels with the medieval belief in The Great Chain Of Being. The Great Chain Of Being was a description of the balance of power and harmony in the world that probably was inspired by Augustinian and Platonic thought. At the  top of the chain was God who was linked to the King who was linked to his Aristocracy. If any part of a the chain was broken then the natural order of the world was disrupted. An example of how this was believed to manifest would be the mysterious change of calm weather to storms and supernatural occurrences in Shakespeare’s Macbeth following the usurping of Duncan. By usurping the legitimate ruler the chain was broken and chaos and disorder in the natural world ensued. Such is the occurrence of injustice in the Polis that the natural harmony will fall apart. I will now summarise the structure of the polis and hopefully answer how the distinctive roles of State and the individual maintain a just society. The state is divided into three classes, a producer class, a guardian (military/police) class and a ruling class. Later, Plato creates a new ruling class out of the guardians and calls the military/police class auxiliaries and this new ruling class guardians. The main point of this is to have each class fulfilling a need in the city and not ‘usurping’ any other person/classes role. Again there are similarities with the great chain of being. Everybody minds their own business and keeps to the plan and eudemonia will be intact. The city is based on various natural needs and recognises that harmony starts with the satisfying of life requirements. This idea is a nearly to a throw back to Cephalus who does not act in an unjust way because he wants for nothing. The development of a citizen starts with education. Students are thought a wide range of subjects from the academic to physical. Children are taught philosophy so that there ‘will be established within them, as in a polis, a politea’ . In other words they will have the same balanced wisdom and discipline governing their souls in life with the eudemonia of the state as a living example for the individual. The education also decided what class and profession the child would fit into. Classes could be transcended as children showed an aptitude for different and subjects abilities. Once an individual was placed in his/her class they remained in it for the duration of their lives. This has distinct parallels with the education system of Ireland were an aptitude in school for the academic can raise points for a place in a college that would further train you for a position of relatively  more power than the ‘producer class’. The most apt at philosophy and reason were sidelined for the upper two classes and had their education furthered accordingly. This begs the question of what would happen if the polis were sacked and all the ruling class slain. How could the polis recover from such an event if the lower classes are conditioned and brain-washed into believing that all they can ever be or do is be the sheep at the bottom of the chain of command? Procreation was also a stage-mannered affair. Parents deemed fit to ‘marry’ (or mate) were coupled off by what they believed to be random selection. In fact, the couples were selected for their eugenic qualities and paired off like horses on a stud. Children are taken from their parents at birth. The knowledge of their parent’s identity is never revealed to them nor is the child’s identity revealed to their parents. This anonymity was meant to promote equality between young and older generations. The child, being in full knowledge that it is from a foster family, would not be subject to family pride and would have no particular loyalties to any family as its siblings and parents would be unknown. Every elder could be addressed as father or mother as every peer could be addressed as brother or sister. With no bias towards any particular individual the harmony of the polis is further maintained. As mentioned earlier, Plato’s great failure from a modern standpoint is his inability to account for emotional aspects in the polis. The idea of splitting families was doomed to failure in that likenesses between siblings and parents would be impossible to disguise and some people could find out their relatives in this way. However, it could be argued that the psychological effect of not knowing ones natural family could be a non-issue after generations of people living in this way. The eugenic selection of partners makes a sense of sorts as families with undesirable inherited characteristics could be prevented from passing them on and those with desirable ones could be encouraged to mate. This is reminiscent of a quasi-nazi formula for the Aryan race of Third Reich. If one looks closer  one can see Plato using injustice to keep justice by lying about the random selection of couples. Due to the constraints of time and space I will have to conclude at this point by summarising the above. Plato essentially defines justice in the state as the three classes staying strictly to their individual roles in order to maintain a balance of responsibilities for the greater good of all. The state does this by ruling of over every aspect of an individual’s life from birth and plotting their destiny with the greater good of the polis to mind. It does this through education, censorship and rigorous controls. Only those with a high knowledge of wisdom (philosophy) are fit to rule as they have enough knowledge to know that justice is best for all as it is an essential virtue of the soul (dikaiosyne). Injustice is considered ignorance, as someone with a lot of wisdom could not possibly see injustice as profitable to anyone. The justice in the soul is described as the virtues (aretai) controlling the appetitive parts of the soul. In this post world war two and post ‘Brave New World’ time, it is easy to take The Republic as a strange Nazi/Taliban-esque tyrannical state on a first glance. As a state the polis would most definitely have failed. As macrocosm for justice in the individual it is unsurpassed. Its influence to this day was evident recently when it was voted best philosophical work ever by readers of the web page http://www.philosophers.co.uk. Whilst it has certain ideas that maybe questioned against the standards of modern western Europeans, it will certainly provide insight and debate on many philosophical issues for many years.