Contributions of Biotechnology to Agriculture

Contributions of Biotechnology to Agriculture Introduction The Food and Agriculture Organization some 20 years ago released a paper stating that the amount of food produced worldwide will not be able to provide the constant nutritional needs for the world population by this year (2010) as a staggering 25% increase in world population was projected, though this estimation has not materialised, it has generated a lot of concerns as there has been a 4-fold population increase in the last century (1918 2009) which has led to the applications of biotechnology to agriculture or in other words the Agrobiotechnology to enhance maximum food production in an economic way. The need for the application of biotechnology to crops was also necessitated as a result of the massive crop loss due to insect pests as at that time was treated with pesticides which are expensive and thus there was a need to sustain the productivity yields of crops which was not given much of a chance as world population was on the rise. Biotechnology was able to provide prospects of producing novel, developed, safer and inexpensive crops in agricultural practices. (Brown, 1992) Agriculture is defined simply as the activities involved in the production of food crops and rearing of livestock animals, while biotechnology was defined jointly by FAO and WHO (1996) as the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services. Therefore Agrobiotechnology techniques according to Huttner et al, (1995) are implemented to reduce cost of production of crops and increasing food productivity by; increasing food quality and food processing traits, adequate disease or pest resistance, improving environmental stress tolerance, and the control of weeds which has led to the development of (genetically modified) GM crops in some parts of the world. Plant breeding techniques with the use of molecular markers such as RFLP, RAPD, AFLP, SSRP, CAPS and SSCP were improved for plants genome mapping as well as to determine plants phenotypes and select desirable traits for the proper modification of crops depending on the gene of interest that is to be incorporated into several populations of plants or crops generated by crosses. (Mohan et al, 1996) Several biotechnology approaches have also been applied in livestock farming basically because there is a general belief that the biotechnological steps to humans are just one step ahead of those applied to animals which involves the modification of animals to observe desirable traits. (Becker and Cowan, 2009) According to Fernandez-Cornejo (2008), the fundamental contributions of the application of biotechnology to agriculture depends on the acknowledgement of its prospective possible benefits and risks, however, this essay will focus on the potential contributions of biotechnology to agriculture (plants and animals) taking into account the advantages as well as the disadvantages of the technology Plant (Crop) Biotechnology Plant biotechnology developments was based on the cell theory as described by Vasil (2007) and has witnessed remarkable expansion in the last 10 years which has focused majorly on making crop production efficient and producing crops with desired traits. Plants and crops need to overcome some Biotic and Abiotic stresses to increase their productivity which led to the introduction of genetically modified (GM) crops about 20 years ago which have been commercialized over the past 10 years either with single traitor multiple traits GM crops as the name implies that genes of a crop are taken and transferred to another crop or already present genes are manipulated with the main purpose of changing the features of the crop in question which may be either the way the crop develops or matures. Addressed in the next paragraph are traits that have been transferred to biotechnology or GM crops to increase their yield. Insect/pest resistance Ferry et al (2005) estimated that 10 20% of major crops are lost to insects or pests and crops are genetically modified to be poisonous and harmful to pests that attack the crops, an example is the application of Bt (Bacillus thuringiensis) genes to grow cotton (in China and South Africa) and corn thereby reducing pesticide use, increasing profits, yields and health benefits to farmers who apply pesticides without protective clothes. (Nuffield Council on Bioethics, 2004) Disease resistance Described in details by Raybould and Gray (1993), fungal, bacterial and viral infestations to crops and plants have been suppressed by genetically modifying plants to be disease resistant for example the ongoing research to reduce the viral and fungal infections to sweet potatoes and bananas respectively. Abiotic stress resistance Motavalli et al (2004) discussed the ongoing extensive research to modify crops to be able to survive in unfavourable environmental conditions such as drought, heat, cold, frost, extreme soil conditions and significantly increase food security for example the use of trehalose genes to grow rice in India to protect it from dehydration. Herbicide tolerance This trait enables a wide range of weeds to be controlled by modifying crops to be resistant to the effects of weed thereby lowering costs of herbicides, reducing tillage and effective weed control measures as discussed in Sharma et al (2002) in the growth of soybeans in Argentina. Improved nutritional value Plant biotechnologies has enabled crops to be modified to contain supplemental nutrients inadequate in diets for example the enhancement of ÃŽ ²-carotene in rice to increase vitamin A to prevent blindness which is as a result of vitamin A deficiency. Biopharmaceuticals Biotechnology applications in plants has been used to produce vaccines and medicines according to Sharma et al (2002) which has enabled production and easy distribution of cheap vaccines as in the modification of potatoes to produce bacterial vaccines for E.coli. GM crops have been widely accepted worldwide (25 countries currently) both in industrial and developing countries as shown in figure 1 mainly because of their advantages which are either economical or environmental. Apart from the fact that plant or crop biotechnology has improved the productivity and yield of crops, other economic benefits in relation to the features of GM crops are further discussed; As described by Nuffield Council on Bioethics (2004), the growth of a large variety of crops by farmers have been enhanced as there a good resistance to biotic (insects, pests or diseases) and abiotic (drought, frost, heat) conditions. With the resistance of GM crops to insects and pests, the use of pesticides is greatly reduced which in turn reduces the costs of growing these crops. Farmers are able to generate more income owing to the reduction of the cost of farming and generation of higher yields which consequently reduce the prices of crops thus alleviating poverty and starvation levels in the economy. GM crops have an improved nutrition levels thus sicknesses and illnesses are consequently averted with a better diet even in underdeveloped countries. Since GM crops can remain fresher over a long period of time for example in tomatoes, the shelf life can be increased in the market. The ability of GMO crops to withstand abiotic conditions such as drought has increased food security while the cheaper production of biopharmaceuticals such as vaccines and other medicines in GM plants has led to a great ease of distribution and manufacture of vaccines thus improving healthcare systems. Environmental benefits of GM crops as discussed by Gatehouse et al (1992); Wieczorek (2003) and Gatehouse (2005), includes the less use or no use of pesticides and insecticides which may be contaminants in the environment (land or water) and could accumulate as residues on foods thus more environmental friendly pesticides can be used while in most cases there is no need to use pesticides. Natural resources sustainability is also improved as there is less use of energy or chemicals (pesticides) while natural habitats are conserved for more efficient applications. GM crops have reduced the pressure on vegetation and biodiversity is maintained while there is a less risk of desertification and soil erosion since GM crops can be grown anywhere irrespective of abiotic conditions. According to the advantages of biotechnology described in figure 2 above, these benefits can only be achieved if the risks and concerns which constitute the disadvantages are investigated, realised and averted. (Mannion, 1995). The potential risks of biotechnology applications to crops and plants can either be health related, environmental or social as further discussed. Wieczorek, (2003) discusses the potential risk of introducing toxins and allergens into GM crops while genetic modification technology is underway is of great concern as there is a potential risk of allergens and toxins being transferred into improved crops while also emphasizing the concerns raised about the use of molecular markers during gene transfer as there is a potential risk of diseases being resistant to clinical antibiotic treatments as a result of transfer of resistance encoding genes which may contain novel bacterial strains. Of great concern as discussed by Hobbs and Plunkett, 1999 is the fact that the long term health effects of the consumption of GM crops over a long time is unknown. Of environmental concerns is the potential risk of GM crops hybridizing with related weeds which may result in superweeds that are more complicated to manage while genetic modification of plants could pose a risk of unintentional gene transfer to non GM crops from GM crops thus the former become wild plants creating ecological instabilities as discussed by Soregaroli and Wesseler, (2003). Wieczorek, (2003) suggests that the release of GM crops into the environment may pose unpredicted and adverse effects as it was emphasized by the fatal actions of Bt corn on the larvae of Monarch butterfly, though the possibility of this happening is very doubtful. Due to the fact that insect pests may get resistant to crop-fortification traits of GM crops, a swift resistance can build up among pest populations as it was feared with Bt crops while biological diversity in nature stand a great risk of being adversely affected as there may be an increase on the reliance of GM crops which could intensif y failure of non-GM crops and put at risk food security. A social concern as discussed by Persley and Siedow, (199) raises the arguments of GM crops being labelled as practiced in the U.S.A where Gm crops carry a label showing a difference in while another concern is the inadequate access to seeds of GM crops or food plants that have been patented as these seeds cannot be saved for replanting. GM crops/food plants have been referred to as unnatural by critics as they are modified by humans and not found in nature as other crops created by God thus causing uproar of religious and ethical concerns as discussed in Knight (2008) while it is feared that these GM plants could someday turn into weeds, adversely affect the natural ecosystem due to direct and indirect impacts on non-targeted plants/crops as described by Azadi and Ho, (2009). Animal Biotechnology Animal biotechnology was described by Cowan and Becker, (2006) as series of techniques by which living beings are genetically modified to benefit humans and animals by exploiting and introducing desirable trait which is as a result of the genetic code being discovered in the early 1950s with technologies including embryo transfer, transgenics, in-vitro fertilization, sexing embryo, cloning and gene knockout but with transgenics being the most commercialized while cloning being the technique surrounded with much controversy. Animal biotechnologies have not received much attention as attributed to plant/crop biotechnology as there is so much controversy surrounding its applications as there is a general concern that these applications could one day be applied to humans since its just a step ahead of the applications to livestock to observe desired traits. Embryo transfer, In-vitro fertilization, sexing embryo and even cloning can be classified as reproducing technologies that have several advantages as described by Gordon, 2004 which includes; the improvement of the reproducing capacities of livestock, the reduction of the level of infertility in animals, enablement of old livestock to donate ovules if they cant maintain pregnancies, the observation of specific sex (male or female) as desired traits while the embryos in all these techniques can also be stored in an embryo bank and can be easily retrieved when required. Gene knockout/targeting techniques has a major advantage of increasing the knowledge of stem cells and similar genes that may be present in humans and livestock and can be use to study diseases and ailments as discussed by Serhan and Ward, (1999). Cloning of animals is also advantageous; as it provides farmers with a range of better performing animals in a generation, is used to improve the population of livestock or endangered animals while inexpensive and many biologically engineered drugs can be modified by using genes that can encode proteins from human as discussed by Van Niekerk, (2005). Application of transgenics which is performed either by microinjection or homologous recombination however is the most advantageous and commercialized animal biotechnology with several examples as shown in table 1, below. As numerous as the advantages and contributions of animal biotechnology are, there are still health, environmental and social concerns that want to constitute as disadvantages to the biotechnology applications for instance the safety of food from GM animals could pose a threat to human health as unpredicted and unintended changes may arise in their composition while environmental issues are based on the break out of gene flow into natural populations as feared especially in superfish as escape into habitats will disrupt natural ecosystems and may cause the introduction of undiscovered genes into the environment. Cowan and Becker (2006). Social acceptance concerns has been a major disadvantage of animal biotechnologies as discussed by Becker and Cowan (2009) which arise from labelling, welfare of animals, genetic biodiversity and trade issues have limited the commercialization of animal biotechnologies. Purpose/ Advantage Animal Models Faster Growth/ Leaner meat Cattle, pig, rabbits, sheep Altered milk composition (higher protein) Cattle Biosteel production in milk Goat Reduced phosphorous in swine feaces (Enviropig) Pig Increased wool production Sheep Disease resistance Pig, sheep, rabbit Xenotransplantation (animal organs for humans) Pig Aquaculture (Growth Hormones of Superfish) Salmon Production of human protein in milk Sheep Production of pharmaceuticals and therapeutics Sheep, cattle Table 1: Applications of Transgenics in Farm Animals. Modified from original source; Cowan and Becker (2006)

Huck Finn Grows Up :: essays research papers

Many changes violently shook America shortly after the Civil War. The nation was seeing things that it had never seen before, its entire economic philosophy was turned upside down. Huge multi-million dollar trusts were emerging, coming to dominate business. Companies like Rockefeller’s Standard Oil and Carnegie Steel were rapidly gobbling up small companies in any way possible. Government corruption was at what some consider an all time high. “The Rich Man’s Club'; dominated the Senate as the Gilded Age reached its peak. On the local front, mob bosses controlled the cities, like Tammany Hall in New York. Graft and corruption were at an all time high while black rights sunk to a new low. Even after experiencing freedom during the Civil War, their hopes of immediate equality died with the death of Lincoln. Groups like the KKK drove blacks down to a new economic low. What time would be better than this to write a book about the great American dream, a book about long h eld American ideals, now squashed by big business and white supremacy? Mark Twain did just that, when he wrote what is considered by many as the “Great American Epic';. The Adventures of Huckleberry Finn, “The great American epic,'; may be one of the most interesting and complex books ever written in the history of our nation. This book cleverly disguises many of the American ideals in a child floating down the Mississippi River on a raft with a black slave. On the outside of the story, one can see an exciting tale of heroism and adventure; however, that is not all. The book shows Mark Twain’s idea of the classic American idealism, consisting of freedom, morality, practicality, and an alliance with nature. Twain manages to show all this while poking fun at the emergence of the “robber barons,'; better know as the big business of the late nineteenth century. Twain portrays many different American values in this book by expressing them through one of the many different characters. The character that Twain chose to represent morality and maturation is none other than Huck Finn himself. Throughout the novel one sees many signs of chang e. The setting is constantly fluctuating, except for the constant Mississippi, and Huck and Jim, a runaway slave, under-go many changes themselves. At the end of the novel Huck Finn shows a large change in his level of maturity than he had exhibited in the beginning of the book.

The Downgrading Demise of Love :: English Literature

The Downgrading Demise of Love â€Å"North Richmond Street, being blind, was a quiet street.† (198). Ignorance is a harmful state of mind, which gives a false sense of happiness to those consumed by it. Ignorance does not allow one to mature by experience of actual events. It shelters one’s perception of actual events by giving illusions of hope. It allows the imagination to instill more meaning into an incident, where there is none. In â€Å"Araby,† James Joyce illustrates how the boy overcomes his oblivious state through irony, epiphany, and symbolism. An obvious example found in the story is the immense amount of irony used throughout â€Å"Araby.† The boy has the idea that love is always perfect and the love he holds for Mangan’s sister is perfect. In the real world, however, he has an aunt and uncle that show what love really is like. When his uncle arrives home late to take him to the bazarre, his aunt begins to argue and demand that he give the boy some money to go to the bazarre (989). The boy completely ignores this glimpse at real life. The boy realizes how life is not perfect and that love is full of compromises. He begins his trip to the bazarre and is excited on the train to arrive at this electrifying event. His idea of the bazarre is that it will be a wonderful place that will make Mangan’s sister fall in love with him. However, when he arrives, he witnesses a dark, dismal place with a grim surrounding (990). Through all the irony in his life, he realizes that he is that opposite of what he is trying to be. Perhaps one of the greatest credentials, which illustrate how the boy is oblivious to the world, is that he realizes his ignorance. All throughout the story, there are innuendoes that he is â€Å"missing something.† Some of these hints range from the symbolic blind houses to his own mental absence at the gathering before he finally gets to go to the fair. His proceeding into the dark, half-closed fair, rather than face the truth that he missed it initially, shows he simply â€Å"does not get it.† Then, however, his realization occurs. In a moment of epiphany, the boy is enlightened to how he has missed even the most obvious fact. On his determination to have his life, as he wants it, he does not realize until the epiphany that Mangan’s sister never likes him. The boy becomes conscious to the fact that he has missed his opportunity from the start. The boy sees for himself that he has

Accountability Issue of Petronas

Accountability issue of PETRONAS-Transparency 1. According to the article written by Datuk Dr Jeffrey Kitingan, a politician from Sabah who was a Vice President of Parti Keadilan Rakyat when he wrote this article. He said that Petronas agreements have been classified as secret. The clauses in the agreement are shielded from public scrutiny, this leads to transparency issue arise and making it an organization without public accountability. For example, 80% of the oil produced by Petronas is not sold directly to the world market but is channeled through six ‘option holders' who obtain the supply from Petronas at below market prices.Only 20% of the oil produced by Petronas is sold through direct open bidding. Because of this arrangement, Petronas is not maximizing its revenue by dealing direct with the open world market. Instead, it has been incurring incalculable losses for the nation and for the people. How much this huge loss is, we will never know. It is understood that this s upply through the option holders is sold by contracts with a binding agreement for 20 or 30 years, causing huge losses for Petronas when oil price increases, as Petronas would then have to continue selling at the old agreed price.Because of the agreement (contract) is not disclose to the public, thus, the public do not know who these option holders are and why they are in the first place. Besides, the public also wondering that are these people representing certain private interests? Because of the non transparent of Petronas agreements, many questions have been raised and the public think Petronas is a huge organization which is not accountable and secretive. 2. The annual report of Petronas is not in detail. For example, we can make a comparison between the 2011 annual report of Shell and 2011 annual report of Petronas.As we can see from the picture below, the related party disclosure of Shell is more detail than Petronas. Shell discloses the company name that where the sale to an d where the purchase from, however, Petronas just disclose the sale and purchases in general. This also means that Petronas annual report lack of transparency. In addition, Shell annual report also provides a detailed information of company properties, whereas, Petronas did not provide this information in annual report. | |

Pressure Measurement and Calibration

52 PRESSURE MEASUREMENT AND CALIBRATION (TH2) 53 EQUIPMENT DIAGRAMS 54 55 56 EQUIPMENT DESCRIPTION Refer to the drawing on pages 56, 57 and 58. This equipment is a bench top unit designed to introduce students to pressure, pressure scales and common devices available to measure pressure. The equipment comprises a Dead-weight Pressure Calibrator to generate a number of predetermined pressures, connected to a Bourdon gauge and electronic pressure sensor to allow their characteristics, including accuracy and linearity, to be determined. The Dead-weight Pressure Calibrator, Bourdon gauge and pressure sensor are mounted on a common PVC base plate. The electrical console is free standing. The Dead-weight Pressure Calibrator consists of precision ground piston (10) and matching cylinder (11) with a set of weights (12). In normal use the appropriate combination of weights is applied to the top of the piston, to generate the required predetermined pressure, and then the piston is set spinning, to reduce vertical friction, while the readings from the measuring devices are recorded. The operating range of the Dead-weight Pressure Calibrator and instrumentation is 20 kNm-2 to 200 kNm-2. The Bourdon gauge (5) and pressure sensor (6) are mounted on a manifold block (2) with a priming vessel (4) to contain the hydraulic fluid which is chosen to be water for safety and ease of use. A priming valve (7) between the reservoir and the manifold block allows the cylinder, manifold block and gauge on test to be easily primed with the water ready for use. A damping valve (8) between the cylinder and the manifold block allow the flow f water to be restricted to demonstrate the application of damping. An additional isolating valve (9) on the manifold block allows water to be drained from the manifold block or allows alternative devices to be connected for calibration. Such devices can be tested over the range 20 kNm-2 to 200 kNm-2. The Bourdon gauge (5) supplied is a traditional industrial instrument with rotary scale and mechanical indicator. The gauge has a 6† diameter dial that incorporates an arbitrary scale calibrated in degrees of rotation (independent of unit pressure) in addition to the usual scale calibrated in units of kNm-2. A clear acrylic front face allows observation of the Bourdon tube the mechanism that converts motion of the Bourdon tube to rotation of the indicator needle. The electronic pressure sensor (6) supplied incorporates a semi-conductor diaphragm that deflects when pressure is applied by the working fluid. This deflection generates a voltage output that is proportional to the applied pressure. The pressure sensor should be connected to the socket (20) marked ‘Pressure Sensor’ on the front of the console. The power supply, signal conditioning circuitry etc are contained in a simple electrical console (15) with appropriate current protection devices and an RCD (26) for operator protection. The electrical console is designed to stand alongside the Dead-weight Pressure Calibrator on the bench top. All circuits inside the console are operated by a main on/off switch (16) on the front of the console. 57 The various circuits inside the console are protected against excessive current by miniature circuit breakers, as follows: CONT (27) O/P (28) This breaker protects the power supply and circuits inside the console. This breaker protects the electrical output marked OUTPUT (23) at the rear of the console. The socket is used to power the IFD3 interface used for data logging. The voltage from the pressure sensor is displayed on a digital meter (17) on the electrical console. An additional conditioning circuit incorporates zero and span adjustments and allows the voltage output from the pressure sensor to be converted and displayed as a direct reading pressure meter calibrated in units of pressure. The zero control (21) and span control (22) are mounted on the front of the console for ease of use. A selector switch (18) allows the voltage from the sensor or the direct reading pressure reading to be displayed as required. The voltage from the pressure sensor is simultaneously connected to an I/O Port (19) for the connection to a PC using an optional interface device (TH-IFD) with educational software package (TH2-303). Alternatively, the signal can be connected to a user supplied chart recorder if required. Before use, the priming vessel must be filled with clean water (preferably deionized or demineralised water) and the calibrator, Bourdon gauge and pressure sensor fully primed. 8 OPERATIONAL PROCEDURES This equipment has been designed to operate over a range of pressures from 0 kN/m2 to 200 kN/m2 may damage the pressure sensors. In order to avoid such damage, DO NOT APPLY CONTINUOUS PRESSURE TO THE TOP OF THE PISTON ROD WHEN THE PRIMING VALVE IS CLOSED except by the application of the masses supplied. An impulse may be applied to the piston when operating at a fluid pressure of less than 200 kN/m2. This procedure is described in Experiment P1. The following procedure should be followed to prime the Dead-weight Calibrator and pressure sensors, prior to taking readings: Level the apparatus using the adjustable feet. A circular spirit level has been provided for this purpose, mounted on the base of the dead-weight calibrator. Check that the drain valve (at the back of the Bourdon gauge base) is closed. Fill the priming vessel with water (purified or de-ionized water is preferable). Open the damping valve and the priming valve. With no masses on the piston, slowly draw the piston upwards a distance of approximately 6 cm (i. . a full stroke of the piston). This draws water from the priming vessel into the system. Firmly drive the piston downwards, to expel air from the cylinder back towards the priming vessel. Repeat these two steps until no more bubbles are visible in the system. It may be helpful to raise the central section of the return tube between the manifold block and the priming vessel. This will help to prevent air be ing drawn back into the system as the piston is raised. Raise the piston close to the top of the cylinder, taking care not to lift it high enough to allow ir to enter, and then close the priming valve. The following procedure describes the calibration of the semiconductor pressure sensor. The procedure differs if using the optional TH-303 software, in which case users should instead refer to the Help Text provided with the software. Remove the piston from the cylinder, and switch the selector knob on the console to ‘Pressure’. This the ‘zero’ control on the console until the display reads zero. This sets the first reference point for the sensor calibration. Return the piston to the cylinder, and reprime the system as described above. Place all the supplied masses onto the piston, with the greatest mass (2 ? kg) being added last. This corresponds to an applied pressure of 200 kN/m2. Spin the piston, and adjust the ‘span’ control until the sensor output matches the applied pressure. This sets the second reference point for the calibration. 59 The calibration may be tested by applying a mass to the piston, spinning the piston in the cylinder, and then comparing the applied pressure to the sensor output. Each ? kg of applied mass corresponds to 20 kN/m2 of applied pressure. This piston itself gives an applied pressure of 20 kN/m2. 0 NOMENCLATURE FOR TH2 The following nomenclature has been used for the theory and calculations presented in this manual: Name Piston diameter Cross-sectional area Mass of piston Mass on mass piston Applied mass Acceleration due to gravity Applied force Nom d A Mp Mm Ma g F Units m m? kg kg kg m/s2 kg Type Given Calculated Given Recorded Calculated Given Recorded Definition The diameter of the dead weight calibrator piston. Cross-sectional area of dead weight calibrator cylinder. Mass of the dead-weight calibrator piston. Mass applied to piston. Ma = Mp + Mm g = 9. 1 m/s2 Force applied to fluid in system by piston and masses. F = g x Ma Pressure applied to fluid by dead weight calibrator P = F/A Ambient (atmospheric) pressure of the surroundings. Applied pressure relative to the pressure of total vacuum Needle angle taken from Bourdon gauge scale Semiconductor output taken from console display Gauge pressure taken from Bourdon gauge scale Calibrated semiconductor output taken from console display Applied pressure Barometric pressure Absolute pressure Needle angle Semi-conductor output Indicated Bourdon gauge pressure Indicated semi-conductor pressure Pa Patm Pabs ? e Pb Ps N/m2 N/m2 N/m2 Calculated Recorded Calculated degree Recorded V N/m2 N/m2 Recorded Recorded Recorded 61 NOMENCLATURE FOR ERROR ANALYSIS The following nomenclature has been used for the error analysis presented in this manual: Name Indicated value Actual value Range Definition Gauge reading, i. e. the pressure indicated by sensor used True pressure, pressure applied by dead-weight calibrator Total range of values covered in the results, or total range of values measurable on instrument scale. Calculation Pi = Pb or Ps, depending on the sensor used Actual value = Applied pressure, Pa Range = Largest result – Smallest result = Pi max – Pi min or Range = Maximum possible reading – Minimum possible reading (200 kN/m? for apparatus used) No calculation. Precise data have a small scatter, indicating minimal random error ea = |Pi – Pa | ea max = ? (Pi – Pa)max? e%a = ea max X 100 Pa e%f = ea max X 100 Range Pmin = P1 + P2 + †¦.. + Pn n da = |Pi – Pmin| dm = da1 + da2 + †¦ + dan n ? = da12 + da32 + †¦ + dan2 n-1 ? Precision How closely the results agree with each other. Actual difference Modulus of the difference between indicated value and actual value Accuracy Maximum difference between indicated pressure and actual pressure Percentage accuracy Greatest difference between of actual scale reading indicated pressure and actual pressure, as a percentage of the actual pressure. Percentage accuracy Greatest difference between of full-scale reading indicated pressure and actual pressure, as a percentage of the range. Mean Sum of results divided by number of results. Absolute deviation Difference between a single result and the mean of several results Mean deviation Sum of the absolute deviations divided by the number of absolute deviations Standard deviation Commonly used value in analysis of statistical data 62 DATA SHEET 7 RELATIVE AND ABSOLUTE PRESSURE The measurement of any physical property relies upon comparison with some fixed reference point. Pressure is one such property, and pressure measurement must begin by defining a suitable fixed point. An obvious reference point is that of the ambient pressure of the surroundings. Pressure scales have been based around a zero point of the pressure of the atmosphere at sea level. Pressures lower than atmospheric are assigned negative values; pressures higher than atmospheric have positive values. Gauges for measuring pressure give readings relative to this zero point, by comparing the pressure of interest to the pressure of the surrounding air. Pressure measured with such a gauge is given relative to a fixed value, and is sometimes termed gauge pressure. Gauge measure pressure difference between the pressure to be measured and the barometric (ambient) pressure. This may then need adjusting, to take into account any difference between barometric pressure and the pressure at sea level. Many calculations using equations derived from fundamental physical laws require absolute pressure values. Absolute pressure is the pressure relative to a total absence of pressure (i. e. a total vacuum). On an absolute pressure scale, all pressures have a positive value. The following chart illustrates the difference between gauge pressure, barometric pressure, and absolute pressure. 63 DATA SHEET 8 TECHNICAL DATA The following information may be of use when using this apparatus: Operating range of dead-weight pressure calibrator Diameter of dead-weight calibrator piston Cross-sectional calibrator area of dead-weight 20 kN/m2 – 200 kN/m2 0. 017655 m 0. 000245 m2 20 kN/m2 150 mL Pressure produced in cylinder by mass of piston with no applied masses Approximate capacity of priming vessel 64 EXPERIMENT P1 CONCEPTS OF PRESSURE AND PRESSURE SENSOR BEHAVIOUR OBJECTIVE To gain a basic understanding of the concept of pressure and its measurement. To investigate the behavior of two kinds of pressure sensor, and the effect of damping on pressure measurement. †¢ To gain a basic understanding of the concept of pressure and its measurement. †¢ To investigate the behaviour of two kinds of pressure sensor †¢ To observe the effect of damping on pressure measurement METHOD To investigate the response of two kinds of pressure sensor to a pressure applied by a dead-weight calibrator device. To investigate the response of these sensors to the application of a sudden pressure spike, with varying levels of restriction of the liquid between the pressure application and the sensor. THEORY Pressure is the force exerted by a medium, such as a fluid, on an area. In the TH2 apparatus, pressure is exerted by a piston on a column of water. The pressure applied is then equal to the force exerted by the piston over the cross-sectional area of the fluid. The use of the piston and masses with the cylinder generates a measurable reference pressure, Pa: Pa = Fa A 65 where Fa = gMa, and Fa = force applied to the liquid, Ma = total mass (incl. piston), and A = area of piston. The area of the piston can be expressed in terms of its diameter, d, as: A = ? d2 4 The units of each variable must agree for the equations to be valid. Using SI units, Pa will be in Newtons per square metre (N/m? , also known as Pascals) if Fa is in Newtons, A is in square metres, and d is in metres. The use of specific units of pressure will be covered in exercise B. For this exercise the area of the cylinder is a constant. The pressure can therefore be considered directly proportional to the mass applied to the mass on the piston Pressure measurement is normally concerned with measuring the effects of a pressure differential between two points in a fluid. The simplest form of pressure sensor is a manometer tube, in which a tube of fluid is exposed at one end to the first point in the fluid, and at the other to the second point. Any pressure differential causes a displacement of fluid within the tube, which is proportional to the difference. Manometers (not included with the TH2 apparatus) are cheap, simple, and can be designed to cover a wide range of pressures. However, they are best used for measuring static pressures below about 600 kN/m? , as the required height of the fluid becomes unworkable at greater pressures. Their dynamic response is poor, so they are best suited to measuring static or slowly changing pressures. Some fluids used are toxic (such as mercury), and may be susceptible to temperature change. The Bourdon-type pressure gauge consists of a curved tube of oval cross-section. One end is closed, and is left free to move. The other end is left open to allow fluid to enter, and is fixed. The outside of the tube remains at ambient pressure. When fluid pressure inside the tube exceeds the pressure outside the tube, the section of the tube tends to 66 ecome circular, causing the tube to straighten (internal pressure lower than the ambient pressure conversely causes increased flattening, and the curve of the tube increases). A simple mechanical linkage transmits the movement of the free end of the tube to a pointer moving around dial. This type of gauge is one of the two kinds included in the TH2 apparatus. The second type of pressure gauge included as part of the TH2 is an electromechani cal device. In a basic semiconductor pressure sensor, silicon strain gauges are fixed to one side of a diaphragm. The two sides of the diaphragm are exposed to the two different pressures. Any pressure differential causes the diaphragm to expand towards the lower-pressure side, producing a change in the strain gauge voltage reading. The electronic semiconductor pressure sensor included with the TH2 is a more refined device with improved reliability and sensitivity for pressure measurement. It includes temperature compensation to reduce the effects of temperature variation on the results. The strain gauges used are formed by laying down a protective film of glass onto stainless steel, followed by a thin film of silicon. The silicon is doped to produce semiconductor properties, and a mask is photoprinted onto it. The unmasked silicon is then removed, leaving a pattern of silicon semiconductor strain gauges molecularly bonded onto the surface of the steel. The gauges are connected to an Ohmmeter through a Wheatstone bridge, to amplify the signal produced. 67 In this type of sensor, a diaphragm is still used, but instead of fixing the strain gauges to the surface, the deflection of the diaphragm moves a steel force rod. This transfers the force to one end of the steel strip that the semiconductor resistors are bonded to. The resulting deflection of the strip causes compression in some strain gauges, and tension in others, changing their resistance and producing a measurable output. Both the TH2 pressure sensors are set up to indicate the pressure differential between atmospheric pressure, and fluid pressurized with the use of the dead-weight calibrator. The fluid passes through a damping valve, positioned between the calibrator and the sensors. By partially closing the valve, fluid flow can be restricted. This affects the speed at which pressure is transferred from the point of application to the sensors. EQUIPMENT SET UP Level the apparatus using the adjustable feet. A circular spirit level has been provided for this purpose, mounted on the base of the dead-weight calibrator. Check that the drain valve (at the back of the Bourdon gauge base) is closed. Fill the priming vessel with water (purified or de-ionized water is preferable). Fully open the damping valve and the priming valve With no masses on the piston, slowly draw the piston upwards a distance of approximately 6cm (i. e. a full stroke of the piston). This draws water from the priming vessel into the system. Firmly drive the piston downwards, to expel air from the cylinder back towards the priming vessel. Repeat these two steps until no more bubbles are visible in the system. It may be helpful to raise the central section of the return tube between the manifold block and 68 the priming vessel. This will help to prevent air being drawn back into the system as the piston is raised. Raise the piston close to the top of the cylinder, taking care not to lift it high enough to allow air to enter, and then close the priming valve. PROCEDURE This equipment has been designed to operate over a range of pressure from 0 kN/m2 to 200 kN/m2. Exceeding a pressure of 200 kN/m2 may damage the pressure sensors. In order to avoid such damage, DO NOT APPLY CONTINUOUS PRESSURE TO THE TOP OF THE PISTON ROD WHEN THE PRIMING VALVE IS CLOSED except by application of the mass supplied. An impulse may be applied to the piston when operating at a fluid pressure of less than 200 kN/m2, as is described later in this procedure. Behavior of pressure sensors Spin the piston in the cylinder, to minimize friction effects between the piston and the cylinder wall. While the piston is spinning, record the angle through which the Bourdon gauge needle has moved, and the voltage output of the electronic sensor. Apply a ? kg mass to the piston. Spin the piston and take a second set of readings for the Bourdon gauge needle angle and the electronic sensor. Repeat the procedure in ? kg increments. When using several masses, it will be necessary to place the 2 ? kg mass on top of the other masses. Repeat the procedure while removing the masses again, in ? kg increments. This gives two results for each applied mass, which may be averaged in order to reduce the effects of any error in an individual reading. Effect of damping Apply a single mass to the piston, and spin it. While the piston is spinning, apply an impulse to the top of the piston by striking the top of the rod once, with the flat of the hand. Watch the behavior of the Bourdon gauge needle. Note the final sensor reading after the response settles. Slightly close the damping valve. Change the mass, spin the piston again, and apply an impulse to the rod. Observe any changes in the sensor responses. Repeat the procedure, closing the damping valve a little at a time and noting the response and the final sensor reading each time. RESULTS Tabulate your results under the following headings:- 69 Mass applied to calibrator Mm (kg) Deflection of Bourdon gauge needle (degrees) Output from electrochemical pressure sensor (mV) Notes on sensor behavior (damping) Plot a graph of sensor response against applied mass for each sensor. 70 EXPERIMENT P2 CONCEPTS OF PRESSURE MEASUREMENT AND CALIBRATION OBJECTIVE To convert an arbitrary scale of pressure sensor output into engineering units. To calibrate a semiconductor pressure sensor. METHOD To make use of a dead-weight calibrator in order to produce known forces in a fluid. THEORY It is recommended that students read Data Sheet 1: Relative and Absolute Pressures before proceeding with this exercise. Pressure sensor calibration Variation in a pressure sensor reading may be calibrated, using known pressures, to give a gauge reading in engineering units. From exercise A, the dead-weight calibrator used in the TH2 produces a known reference pressure by applying a mass to a column of fluid. The pressure produced is Pa = F Aa where Fa = gMa, and Fa is the force applied to the liquid in the calibrator cylinder. Ma is the total mass (including that of the piston) 71 g is the acceleration due to gravity, and A is the area of piston. The area of the piston can be expressed in terms of its diameter, d, as: A = ? d2 4 The pressure in the fluid may then be calculated in the relevant engineering units. These known pressures may then be compared to the pressure sensor outputs over a range of pressures. The relationship between sensor output and pressure may be turned into a direct scale, as on the Bourdon gauge scale. Alternatively, a reference graph may be produced. Where the relationship is linear and the sensor output is electrical, the sensor may be calibrated using simple amplifier (a conditioning circuit). When using SI units, the units of pressure are Newtons per square meter (N/m? , also known as Pascals). To calculate the pressure in N/m? , M must be in kg, d in m, and g in m / s?. For the pressure range covered in this exercise, it will be more convenient to use units of kN/m? , where 1 kN/m? = 1000 N/m? (1 N/m? = 0. 001 kN/m? ). Barometric pressure: pressure units and scale conversion Barometric pressures is usually measured in bar. One bar is equal to a force of 105 N applied over an area of 1m?. While bar and N/m? have the same scale interval, pressure in bar often has a more convenient value when measuring barometric pressure. Pressure may also be measured in millimetres of mercury (mmHg). The pressure is given in terms of the height of a column of mercury that would be required to exert an equivalent pressure to that being measured. Another possible unit of measurement is atmospheres (atm). One standard atmosphere was originally defined as being equal to the pressure at sea level at a temperature of 15 °C. A pressure unit still in everyday use is pounds per square inch (psi or lbf / in.? ). One psi is equal to a weight of one pound applied over an area of 1 in.? If a barometer is available to measure the ambient pressure in the room where the equipment is located, the barometer reading should be converted SI units. Pressures may be converted from one scale to another using a conversion factor. A list of conversion factors is provided below. 72 1 atm = = = = = = = = = = = = = = = = = = = = 101. 3 x 103 101. 3 1. 013 760 14. 696 100 x 103 100 0. 987 750. 006 14. 504 133. 3 x 103 133. 3 1. 33 1. 316 19. 337 6. 895 x 106 6. 895 x 103 68. 948 68. 046 51. 715 N/m2 kN/m2 bar mmHg psi N/m2 kN/m2 atm mmHg psi N/m2 kN/m2 bar atm psi N/m2 kN/m2 bar atm mmHg 1 bar 1 mmHg x 103 1 psi x 103 ADDITIONAL EQUIPMENT REQUIRED Values for the piston diameter and weight are provided. These may be replaced by your own measurements if desired. The following equipment will be required to do so: a) Vernier calli pers or a ruler, to measure the piston diameter b) A weigh-balance or similar, to measure the piston weight EQUIPMENT SET UP Carefully remove the piston from the cylinder, weigh it. Take care not to damage the piston, as it is part of a high precision instrument and any damage will affect the accuracy of the experimental results. Level the apparatus using the adjustable feet. A circular spirit level has been mounted on the base of the dead weight calibrator for this purpose. Check that the drain valve (at the back of the Bourdon gauge base) is closed. Fill the priming vessel with water (purified or de-ionized water is preferable). Open the damping valve and the priming valve. 73 With no masses on the piston, slowly draw the piston upwards a distance of approximately 6cm (i. e. full stroke of the piston). This draws water from the priming vessel into the system. Firmly drive the piston downwards, to expel air from the cylinder back towards the priming vessel. Repeat these two steps until no more bubbles are visible in the system. It may be helpful to raise the central section of the return tube between the manifold block and the priming vessel. This will help to prevent air being drawn back into the system as the piston is raised. Raise the piston close to the top of the cylinder, taking care not to lift it high enough to allow air to enter, and then close the priming valve. Set the selector switch on the console to ‘Output’. PROCEDURE This equipment has been designed to operate over a range of pressure from 0 kN/m2 to 200 kN/m2. Exceeding a pressure of 200 kN/m2 may damage the pressure sensors. In order to avoid such damage, DO NOT APPLY CONTINUOUS PRESSURE TO THE TOP OF THE PISTON ROD WHEN THE PRIMING VALVE IS CLOSED except by application of the mass supplied. Conversion of an arbitrary scale into engineering units Spin the piston to reduce the effects of friction in the cylinder. With the needle still spinning, record the angle indicated by the Bourdon gauge needle. Place a ? kg mass on the piston, and spin the piston. Record the value of the applied mass, and the angle indicated by the Bourdon gauge needle. Increase the applied mass in increment of ? kg. Spin the piston and record the needle angle each increment. Repeat the measurements while decreasing the applied mass in steps of ? kg. This gives two readings for each applied mass, which may be averaged to reduce the effect of any error in an individual reading. Calculate the applied pressure at each mass increment. Calculate the average needle angle at each pressure increment. Repeat the experiment, this time recording the applied mass and the indicated pressure on the Bourdon gauge scale. Compare this to the average needle angle recorded previously. 74 Calibration of a semiconductor pressure sensor NOTE: This procedure differs if the TH2-303 software is being used. Please refer to the online product Help Text if using this software. Spin the piston. Record the voltage indicated on the semiconductor output display on the console. Place a ? kg mass on the piston, and spin the piston. Record the applied mass, and the voltage indicated on the semiconductor output display on the console. Increase the applied mass in steps of ? kg, spinning the piston and recording the semiconductor output each time. Repeat the measurement while decreasing the applied mass in steps of ? kg. Calculate the applied pressure at each mass increment. Calculate the average sensor output at each pressure increment. Slowly open the priming valve. Open the valve to its maximum, and check that the damping valve is also fully open. The fluid in the system will now be at approximately atmospheric pressure (it will be slightly higher than atmospheric due to the height of fluid in the reservoir, but this is negligible compared to the range of the sensors). Switch the selector knob on the console to PRESSURE Turn the ZERO control on the console until the display read zero, to set the first reference point for the sensor calibration. Raise the piston close to the top of the cylinder, taking care not to lift it high enough to allow air to enter, and then close the priming valve. Place a large mass on the piston, and calculate the corresponding applied pressure. Spin the piston and adjust the SPAN control until the sensor output matches the applied pressure, to set the second reference point for the calibration. Remove the masses from the piston. Take a set of readings from the calibrated semiconductor sensor, by adding masses to the piston in ? kg increments. Repeat the reading while decreasing the applied mass. This gives two reading for each applied mass, which may be averaged in order to reduce the effect of any error in an individual reading. 75 RESULTS Tabulate your results under the following headings: Barometric pressure Mass of piston Mp Diameter of cylinder, d Cross-sectional area of cylinder, A Mass on piston Mm (kg) Applied mass Ma (kg) Applied force Fa (N) Applied pressure †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. Needle angle N/m2 kg m m2 Indicated Indicated SemiBourdon conductor semiconductor pressure pressure output Pb Ps Pa E ? (mV) (N/m2) (degrees) (N/m2) (N/m2) Plot graphs of average needle angle against applied pressure for the Bourdon gauge, and voltage output against applied pressure for the semiconductor sensor. Plot a graph of indicated pressure against actual pressure for the Bourdon gauge and the calibrated semiconductor pressure sensor. If there is facility for measuring barometric pressure, it is possible to calculate the absolute pressure corresponding to each applied pressure increment. The ambient pressure of the surroundings, Patm should be measured, then converted into N/m2 (if required). An additional column should be added to the results table: Absolute Pressure, Pabs (N/m2). Absolute pressure may then be calculated as Pabs = Pa + Patm 76 EXPERIMENT P3 ERRORS IN PRESSURE MEASUREMENT OBJECTIVE To investigate the sources of error when measuring pressure. METHOD Errors in measuring a quantity, such as pressure, can come from a number of sources. Some can be eliminated by careful choice of equipment and experimental method. Other errors are unavoidable, but can be minimized. In any experiment, it is good practice to note any possible sources of error in the results, and to give an indication of the magnitude of such errors. Errors fall into three general categories: Avoidable errors These are errors that must be eliminated, as any results including such errors will often be meaningless. Such errors include: †¢ †¢ †¢ †¢ Incorrect use of equipment Incorrect recording of results Errors in calculations Chaotic errors, i. e. random disturbances, such as extreme vibration or electrical noise that are sufficient to mask the experimental results. 7 Random errors Random errors should be eliminated if possible, by changing the design of the experiment or waiting until conditions are more favorable. Even if they cannot be eliminated, many random errors may be minimized by making multiple sets of readings, and averaging the results. Random errors include: †¢ †¢ †¢ †¢ Variation of experimental conditions (e. g. changes in ambie nt temperature) Variation in instrumentation performance Variation due to material properties and design (e. g. effect of friction) Errors of judgement (e. g. nconstancy in estimating a sensor reading) Systematic errors Systematic errors produce a constant bias or skew in the results, and should be minimized where possible. They include: †¢ †¢ †¢ †¢ Built-in errors (e. g. zero error, incorrect scale graduation) Experimental errors (due to poor design of the experiment or the apparatus) Systematic human errors (e. g. reading from the wrong side of a liquid meniscus) Loading error (errors introduced as a result of the act of measurement- for example, the temperature of a probe altering the temperature of the body being measured) Errors may also be described in a number of ways: Actual difference – the difference between the indicated value (the value indicated by the gauge or sensor) and the actual scale reading (the true value of the property being measured). The actual value must be known to calculate the actual difference. Accuracy – the maximum amount by which the results vary from the actual value. The actual value must be known. Percentage accuracy of the actual scale reading – the greatest difference between the actual value and the indicated value, expressed as a percentage of the actual value. The actual value must be known. Percentage accuracy of the full-scale reading (total range of the measurement device) – the greatest difference between the actual value and the indicated value, expressed as a percentage of the maximum value of the range being used. The actual value must be known. Mean deviation (or probable error) – The absolute deviation of a single result is the difference between a single result, and the average (mean) of several results. The mean deviation is the sum of the absolute deviations divided by their number. The actual value is not required. The mean deviation is an indication of how closely the results agree with each other. 78 Standard deviation (or mean square error) – the standard deviation is the square root of the mean of the squares of the deviations (‘better’ results are obtained by dividing the sum of the values by the one less than the number of values). This is a common measure of the preciseness of a sample of data- how closely the results agree with each other. The actual value is not required. ADDITIONAL EQUIUPMENT REQUIRED Values for the piston diameter and weight are provided. These may be replaced by your own measurements if desired. The following equipment will be required to do so: †¢ †¢ Vernier callipers or a ruler, to measure the piston diameter A weigh-balance or similar, to measure the piston weight EQUIPMENT SET UP To prime the cylinder, the following procedure should be followed (where this is required in the experiment): Level the apparatus using the adjustable feet. A circular spirit level has been mounted on the base of the dead weight calibrator for this purpose. Check that the drain valve (at the back of the Bourdon gauge base) is closed. Fill the priming vessel with water (purified or de-ionized water is preferable). Fully open the damping valve and the priming valve. With no masses on the piston, slowly draw the piston upwards a distance of approximately 6cm (i. e. a full stroke of the piston). This draws water from the priming vessel into the system. Firmly drive the piston downwards, to expel air from the cylinder back towards the priming vessel. Repeat these two steps until no more bubbles are visible in the system. It may be helpful to raise the central section of the return tube between the manifold block and the priming vessel. This will help to prevent air being drawn back into the system as the piston is raised. Raise the piston close to the top of the cylinder, taking care not to lift it high enough to allow air to enter, then close the priming valve. PROCEDURE This equipment has been designed to operate over a range of pressure from 0 kN/m2 to 200 kN/m2. Exceeding a pressure of 200 kN/m2 may damage the pressure sensors. In order to avoid such damage, DO NOT APPLY CONTINUOUS PRESSURE TO THE 79 TOP OF THE PISTON ROD WHEN THE PRIMING VALVE IS CLOSED except by application of the mass supplied. The following experiments give suggested ways in which particular sources of error may be investigated. It is recommended that only one or two be attempted in a single laboratory session, with each being repeated several times, giving multiple samples for the error analysis. Basic Error Analysis: The accuracy of the semiconductor calibration may be investigated by performing standard error calculations on the calibrated sensor output, using the results obtained in Experiment P2. If results are not available for analysis, the following procedure should be followed: Slowly open the priming valve. Open the valve to its maximum, and check that the damping valve is also fully open. The fluid in the system will now be at approximately atmospheric pressure (it will be slightly higher than atmospheric due to the height of fluid in the reservoir, but this is negligible compared to the range of the sensors). Switch the selector knob on the console to PRESSURE. Turn the ZERO control on the console until the display read zero, to set the first reference point for the sensor calibration. Raise the piston close to the top of the cylinder, taking care not to lift it high enough to allow air to enter, then close the priming valve. Place a large mass on the piston, and calculate the corresponding applied pressure. Spin the piston, and adjust the SPAN control until the sensor output matches the applied pressure, to set the second reference point for the calibration. Remove the masses from the piston. Take a set of readings from the calibrated semiconductor sensor, adding masses to the pan in ? kg increments, and again while decreasing the applied mass. This provides two set of readings for data analysis. The experiment should be repeated to provide further sets of data. Avoidable errors: Incorrect use of equipment Level the apparatus using the adjustable feet. A circular spirit level has been mounted on the base of the dead-weight calibrator for this purpose Check that the drain valve (at the back of the Bourdon gauge base) is closed, and the damping valve is fully open. 80 Remove the piston from the cylinder, then fill the priming vessel with water (purified or de-ionized water is preferable). Close the priming valve, then replace the piston in the cylinder. Take a set of readings without priming the system first. Random errors: Friction effects Prime the system as described in the equipment set up instructions. Tilt the board at an angle of about 5 to 10 degrees. THE EQUIPMENT BASE MUST STILL BE FIRM AND SECURE. Titling the apparatus in this way will exaggerate any friction effects, as the force applied by the piston will no longer be acting straight downwards on the column of fluids, but will have components acting at right-angles to cylinder wall. Spin the piston. Take one reading while the piston is spinning, then observe the behavior of the needle. Continue to watch the needle as the piston stops spinning, then make a note of the new gauge reading. Apply masses to the piston in ? kg increments. At each step, spin the piston, note the sensor output, and then take a second reading after the piston stops spinning. Systematic errors: Zero error Calibrate the semiconductor pressure sensor, but do not include mass of piston in the applied mass when calculating the applied pressure. Take a set of readings from the calibrated semiconductor sensor over a range of applied masses, now including the piston mass in the applied mass calculation. Human error Take a set or readings from the Bourdon gauge pressure scale, but stand at an angle to the dial face when taking each reading. Keep the same viewing angle for each reading. This illustrates the effect of parallax on the readings taken. RESULTS Tabulate your results under the headings on the following page: For each result, calculate the absolute difference, ea between indicated value Pi and the applied pressure Pa. 81 Find the maximum absolute difference, the accuracy ea max and use this value and the corresponding indicated pressure to calculate the % accuracy of actual scale reading and the % accuracy of full-scale reading (use a range of 200 kN/m2). Correlate the data for several test runs, to give a set of indicated pressure readings corresponding to a single applied pressure. Use this correlated data table to calculate the mean of the results, Pmean, the mean deviation, dm, the absolute deviation, da, and the standard deviation, ?. Errors can also be illustrated graphically: 85 Piston diameter, d = †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. m Piston mass, MP = †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. kg Experimental conditions : †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ Mass Applied Applied Applied Indicated Mean Absolute Standard Actual Accuracy % % Mean on deviation deviation deviation Accuracy Accuracy of mass force pressure pressure difference piston Actual Full result scale scale reading reading Mm dm da PI ea Emax e%a e%f Pmin Ma Fa Pa ? kg) (kg) (kN) (kN/m2) (kN/m2) (kN/m2) (kN/m2) (kN/m2) (kN/m2) 86 Plot a graph of actual pressure against indicated pressure. On the same graph, plot a straight line showing the actual pressure. This will illustrate three characteristics of the results: †¢ †¢ Deviati on of sensor readings from the actual value. Whether any deviation from the true reading is systematic (the graph will be a straight line or a smooth curve) or random (the graph will have no obvious relationship). Precision of the results. Precise results will be close together, not widely scattered. Precise results may still deviate strongly from the actual value. †¢

Apple International Marketing Essay

1. If you would be working for Apple (Ipad or Iphone) what strategies would you pursue in order avoid situation like what is happening today to Nokia Apple Inc. has already had a spectacular break-through in the technological race when it firstly released Iphone in 2007. Since when, there was a revolution in the technology field especially, in the Personal Computer (PC) industry involves: smartphone and tablet computer. If I worked for Apple Inc., in order to retain as well as to enhance the position of Apple in Today’s market, I would apply, deploy and develop the Relationship marketing with â€Å"Differentiation† strategies based on 4P includes: Product-Price-Promotion-Place. Product Firstly, people have to admit the truth that the present success of Apple was built on the brilliant products. Compared to Nokia, Apple already created a key competitive advantage that raises company to a new level. The failure of Nokia was a cost lesson for others mobile phone manufacturer in the world. The main reasons leading Nokia to this moment situation is company already missed a valuable opportunity in smartphone revolution as well as its products. Even though, later on Nokia unveiled smartphone Lumia but it did not satisfy the consumers’ demand and expectation. Nokia product’s designs are not attractive and fashionable as Iphone. In addition, the products are outdated interface, lack of applications and outdated technologies compared to Apple’s products. Consequently, Nokia loose its leading brand value in the mobile phone industry. Meanwhile, Apple realized and took that opportunity then turned it into huge success. Hence, Apple should continue the product differentiation strategy. It mainly focuses on investing more in creating and developing the new and innovative technologies, which are totally different from competitors’. The products should be usually updated and upgraded in both its particular outlook (thinnest, most lightweight, unique, fashionable and outstanding) and functions (convenient, ease-use, support applications and service etc.). This is the only way to make company continue keep its crown as innovator in the intensive technological competition. Price Secondly, despite the Apple is assessed as â€Å"the tech industry’s high-price leader† with Premium price, people are still willing to purchase its products at a particular price. The main point is price set based on the â€Å"product Differentiation strategies†. Therefore, in order to exist and grow in the price war, the company not only retain the same price strategy but also use more the pricing Skimming and Reference strategies: launching a same product line but in different price points depending on the features and drive capacities. It may be better for Apple than using the penetration pricing strategies by suddenly decreasing the price to expand or approach new market. Promotion In order to get the large impact from media and society, one key in the Apple’s marketing is its traditional promotion strategies by creating hype and excitement before the launch of products. Apple is considered as â€Å"Phenomenon† and each marketing communication relating to â€Å"Word of mouth† created huge impact on consumer behavior. Organizing significant campaigns with special slogan to introduce and get emotional response about the new products, which concentrate on the consumer psychology: the curiousness, self-esteem, desire and passion in new technologies Place Finally, expanding and opening new multi-distribution channels with high sales volume (retail store chain and online sales). Simultaneously, more creating the strong relationship with worldwide retail partners. In conclusion, Relationship Marketing based on â€Å"Differentiation strategies† focusing on customer retention and satisfaction, which in order to enhance, increase customer loyalty and sustainable development. Apple Inc. has to understand the market dynamic to keep its track as market driven by inventing the unique and creative product lines as well as innovation technology. 2. On the other hand, if you would be working for a competitor of Apple (Tablet or mobile), what strategies would you adopt in order to compete against Apple Apple (Iphone and Ipad) is considered as the biggest rival in the PC industry of Samsung (Galaxy S), Nokia (Lumia), Google (Nexus), Amazon (Kindle Fire). Even though, Apple has been dominating the PC industry but its target market selection is â€Å"Market specialization†. The weakness of Apple is the limited market share because of the premium price and most Apple content can only run on its selected devices. If we are competitors of Apple, we can use the Apple’s strategies to compete against it. It means we should also apply the â€Å"Differentiation strategies† to provide more perceived value to consumer. Every time, Apple releases new product or any application, we might prepare to create and unveil our amazing different products with adding more value proposition. Take for instances, to accompany with product, we can offer new innovative or free (or low cost charge) applications, software, movies, TV shows, games, e-books, cloudy computing or even more drive capacity etc. Although, we do not have as strong customer loyalty as Apple has, our competitive advantage is offering the same product’s quality with a competitive price which is less than Apple’s but still not too low to confirm our position in the market. In addition, as some Apples’s competitors (eg: Kindle of Amazon) did, they used the bundle pricing strategies combine two or more products and sell these at a reduced price or offer programs: buy once but easy to access content on other devices ipad, iphone, tablets . Then little by little getting the expansion international scale with â€Å"Full market coverage† (different product lines suitable for every customers) through different market entries, distribution channels and marketing communication campaigns. 3. Make a SWOT analysis for Apple (Ipad and Iphone) Apple’s SWOT analysis a. Define what are the biggest threats and opportunities for Apple in the future Threats Nowadays, the high technology industry seems to be in the â€Å"Saturation† but in the future, people still believe there would be remarkable changes. In the future, the most threats that Apple may face is the intensive and high level in technology competition. The threats might be coming from both existing and emerging competitors. The growing in the market share leads to the consequence that there growth in perception and needs/demands of customers. In addition, there are more and more counterfeit and fake products overflowing market that affect directly to the company image and sales. If Apple cannot find the solution, soon company is surpassed by others competitors. Opportunities: Ranking as a top leading innovator brings many open-opportunities for Apple. The biggest opportunity of Apple is changes in technology offer new and innovative products. The company can even get and deploy from the outsourcing for its research and development. Creating the technology revolution and changing desire of information age affecting to most generations. As one of the most famous philosophies of strategic marketing pioneer – Regis McKenna: â€Å"Markets for new innovative products do not exist, they have to be created, and defined†. Therefore, creating and expanding the product/service lines by Apple could help them define its market, raise sales and increase their product portfolio. b. Define what are the biggest strengths and weaknesses of Apple today Strengths In 2012, this is the second time when Apple is ranked the world’s most valuable brand according to â€Å"The 2012 BrandZ Top 100 Most Valuable Global Brands†. It is said that the Apple’s brand success is driven by three elements confidence, competence and customers. Might be the reason why people purchase Apple’s product because they just care about its brand and image. As the David Haigh stated in the annual report on the world’s most valuable global brands: â€Å"Brands are the most valuable assets in business today. They drive demand, motivate staff, secure business partners and reassure financial markets. Leading edge organizations recognize the need to understand brand equity and brand value when making strategic decisions† – David Haigh, CEO, Brand Finance plc. Apple is successful in creating its identity and emotional branding that all most the whole world can recognize. Long term brand building will engage consumers on a variety of touch points that create the high loyalty. Weaknesses Entering the Niche market with the premium price strategies, which can considered as Apple’s weakness. The price wars between competitors will also affect to Apple’s profits. Moreover, the company’s target market selection is â€Å"Market specialization† then it quite limits the market share cause products provided by Apple meet the demand of middle/ upper class and people are interested in innovation technology. Reference Mr. Francois Simon’s lecture and materials http://www.tutor2u.net/blog/index.php/business-studies/comments/nokia-and-strategic-change-the-essential-a2-business-case http://theapplephenomenon.blogspot.fi/ http://www.brandfinance.com/images/upload/bf_g500_2012_web_dp.pdf http://www-sul.stanford.edu/mac/mckenna.html http://www.wpp.com/wpp/press/press/default.htm?guid={92b52c53-fc68-45e0-aaea-34fe6fbd769b} http://www.amazon.com/gp/feature.html?ie=UTF8&docId=100071977 http://www.saleschase.com/blog/2012/04/03/little-known-secrets-of-apples-pricing-strategy/ http://www.saleschase.com/blog/2012/03/13/the-best-of-apples-marketing-strategies/ http://blog.openviewpartners.com/apples-marketing-strategy-history-repeats-itself/ http://blogs.gartner.com/eric-knipp/2009/09/28/cost-leadership-and-differentiation/ http://www.slideshare.net/kaushiik10/apple-inc-marketin-and-distribution-strategy

Literary Technique in “The Story of an Hour” and “A Rose for Emily”

The protagonists of â€Å"The Story of an Hour,† by Kate Chopin and â€Å"A Rose for Emily,† by William Faulkner long for a freedom withheld by the heavy hand of their surroundings. At the presentation of both these stories, it is easy to see how this could become a classic telling of the Southern condition but the skillful use of foreshadowing and symbolism creates irony in a series of seemingly ordinary events. Both women in these stories were bound by the strict expectations of their society.Louise and Emily not only feel but also live by the demands that society and their families have placed on them. When they finally realize their sovereignty, they attempt to maintain it in the most unconventional manner. In Faulkner’s â€Å"A Rose for Emily,† Emily endures the push and pull of social graces and the strict expectations of a lady well into her life. After her father, and last attachment to pre-war decencies, passes, Emily confines herself to her home. She eventually begins to date a young man, Homer Baron, a day laborer and heavy drinker who is far from the accepted suitor. Emily seems to have achieved her purpose as a true Southern lady when she marries Baron. For reasons unbeknown to her ever-prying town, she then boards up her home and never leaves again. Upon her death the town realizes that Baron died, or rather had been killed, shortly after the wedding while his corpse lay in the marriage bed ever since.This absolute preservation of a thriving time was the only way Emily could maintain freedom in her mind. Emily had become so engrossed in the norms of her culture that her world became too small to live in. Caught in the societal transition of Civil War aftermath) and with the constant vigilance of Emily by the townspeople, we can see there is no option for complete fulfillment in her life. Her choice to live in a â€Å"snapshot† of her life becomes the only adequate one. Like Emily, the protagonist in â€Å"The Sto ry of an Hour,† Louise, feels inhibited in her life.When Louise Mallard is told of her husband's death, she rejoices seeing the possibility for a new course in life, free from the obligation of marriage. In the early moments of her new venture, it is discovered her husband is in fact alive. She was imprisoned in her husband's life, free in his death, and then entombed by the realization of the misinformation. Brently Mallard's death symbolizes the end of obligatory formalities on Louise; the loss of her new found freedom stops her heart from beating.It is clear that the expectation of Louise is so overwhelming that her body literally cannot sustain its pressure any longer. In the beginning of the story the reader is warned of Louise’s heart troubles, it is then discovered this â€Å"trouble† may have manifested because of her conformation to social practices. This story initially leads the reader to a presumption of a typical reaction by a genteel Southern woman, but with the admission into the true thoughts of Louise, the reader may see what is customary is not always what is natural.The characters of â€Å"The Story of an Hour† and â€Å"A Rose for Emily† personify women who have been lost in a world cultured by society, inhibited by its demands and mistaken by its perceptions. These stories force a more critical reading of what could be seen as â€Å"typical† behavior. The controversies of the Southern tradition are personified in both characters, representing larger ideas that would perpetuate the downfall of a culture. As these stories employ foreshadowing as a literary tactic, the stories themselves aim to suggest an unfavorable end if reconsideration is not given to the status quo.