Pcl and Gpr free essay sample

Theory of Electromagnetic detection Mechanism behind PCL is Biot-Savart Law, which is an equation that describes the magnetic field generated by an electric current. The law is used to compute the resultant magnetic field B at position r generated by a steady current I (for example due to a wire). It means a continual flow of charges which is constant in time and the charge neither accumulates nor depletes at any point. It is a physical example of a line integral: evaluated over the path C the electric currents flow. The equation in SI units is  where dl is a vector whose magnitude is the length of the differential element of the wire, in the direction of conventional current, and ? 0 is the magnetic constant. Since the field surrounds the conductor and obeys the RHSR as shown in the following figure, it is a vector quantity, in which each point has magnitude and direction. We will write a custom essay sample on Pcl and Gpr or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Figure2: Magnetic field B at position r generated by a steady current I How can underground pipes and cables be located by PCL locator A Pipe Cable Locator detects a magnetic field around the line created by an alternation current flowing along the line. PCL detect magnetic fields Alternate electromagnetic current creates a moving and reversing magnetic field. When the receiver detects the presence of a conductor, signal appears. Afterwards, the strength of the signal is shown on the screen. The operator reads the response of the locator and interprets the result. Figure 4: Alternate electromagnetic current Difference between Passive and Active mode detection For passive detection, the signals are naturally present in conductors. The only equipment is a receiver. The application is to sweep and search for the existence of conductors buried underground. It emits 50 Hz and radio frequency. Its detection by radio is less definite. It should not be relied upon for depth measurement. For active detection, it requires the use of a signal generator (transmitter) to trace and pinpoint target lines. Signal can be transmitted to the cable by induction or signal clamp. It allows more precise work such as depth measurement and signal strength comparison. Passive modeActive mode – Direct connection Active mode – Signal clampActive mode Induction Table 1: Passive mode and Active mode detection Why passive mode is unreliable It is unable to identify the conductors unless tracing to the source to obtain clues. Passive signals can be unobvious. Frequency of signals is not relevant to the voltage. Frequency of signals depends on strength of the current and depth of the line. The result of passive detection can only be taken as reference but not accurate measurement. The function of a transmitter Transmitter discharges an identifiable signal and applies the signal to the target line. The receiver than traces and locates the lines by detecting the applied signal. It can also flood with signal and energize the lines in that area. Accessories are optional. Direct connection uses a pair lead (red for connection and black for grounding). Signal clamping uses a signal clamp. Direct connection Signal clamping ? Induction Table 2: the three main types of Active mode detection For direct connection, since contact to cable is necessary, this method is not suitable to detect electric cable but suitable to metallic pipe. Signal clamping is the most effective method. It can be applied to exposed cable (trail hole). However, the size of the cable is limited by the size of the clamp. The jaws of the clamp must be closed completely. For induction method, signal can be applied without access to the line. However, it is not accurate method since signals can induce onto nearby lines as well as the target. It is also inefficient on deep targets. Ground Penetrating Radar (GPR) For the data collection part of GPR, the elapsed time between radar energy generation, reflection from the ground and the final record of reflected wave at the receiving antenna is measured. The amplitude and wavelength of the reflected radar waves received back to surface are also amplified for processing and viewing on a computer screen (Conyers, 2004). Reflection of radar energy occurs when energy enters into a material with different electrical conduction properties from materials it left. The amplitude of the reflection depends on the contrast in the dielectric constants of the two materials. High amplitude reflections usually appear when there is a sudden change in water content, lithologic or mineralogic changes (Laskowski W. , 2010). The following shows Schematic illustration of common-offset, single-fold profiling along a line showing major survey specification parameters. Fig. 5 Showing Schematic illustration of common-offset, single-fold profiling along a line showing major survey specification parameters. According to Conyers (2004), radar energy emits from the GPR antenna downward to the ground surface is of conical shape. Therefore reflected radar energy received by antenna may not come from buried objects that are directly below the antenna but still within the â€Å"beam† of propagating waves. Oblique radar wave travel to and from the ground surface is longer in distance and travelling time. These reflected radar wave will still be recorded by the antenna as if directly below the antennas, but deeper in the ground. When the GPR is propelled forward on the ground in transect, the antenna moves closer gradually to the buried object. The antenna will continually record reflections from the buried object before arriving on top of the object and continue to record after passing it. The following shows a signal paths between a transmitter and a receiver on the surface treated as rays following the paths. Fig. 6 A signal paths between a transmitter and a receiver on the surface treated as rays following the paths. A=direct airwave G=direct ground wave R=reflected wave C=critically refracted wave These transmitting and receiving radar waves produce a reflection parabola as time for radar wave transmit and reflect back to antenna is longer for point sources of reflection that are locate obliquely from the antenna. Two-way time traveled when antenna is moving close to the object will be shorter until the antenna reaches the top of the object. The situation is the reverse when the antenna moves away from the top of the object. Therefore, the apex of the parabola denotes the actual location of the buried point sources of reflection while the arms of the parabola are generated when the antenna receive the oblique radar wave.

Ethical Research Conduct

Ethical Research Conduct Introduction A research must have a researcher, research tools, participants and an audience. This paper explores various ethical considerations that must be followed when seeking consents from participants.Advertising We will write a custom essay sample on Ethical Research Conduct specifically for you for only $16.05 $11/page Learn More Philosophical and Historical Background Consent is a permission given to researchers to involve participants in a research process. This consent may be written or verbal depending on the nature of the study and the relation between the participant and researcher (Kim 2009). Philosophers believed that research consent is essential in all research involving human beings since it makes all parties concerned to be aware of the processes involved in the study. This is based on previous attempts to conduct research without the consent of participants which led to complications (withdrawal of participants, insufficient cooperation and hostility) during the study (Comstock 2013). These challenges necessitated the need to develop ways of ensuring participants obey the agreement signed before the study started. Therefore, participants were compelled to play their roles until when the process is completed. Ethical Issues in Articles 3.1-3.5 Article 3.1 explains that researchers must seek the participation of other people in the research by requesting them to be involved. This means that the researcher must not use force, manipulation, propaganda or gifts to persuade participants to agree to take part in the research (Comstock 2013). Most research processes take a lot of time and this may force participants to withdraw from the process. This has serious effects on the outcomes of the research if the participant is forced to sit through the whole process. Therefore, it is necessary to obtain voluntary consent from the participant before commencing with the research. Participants that volunteer to participate in res earch usually provide credible information in terms of accuracy and reliability. However, when a participant is forced to take part in a study the person may offer false information which will affect the research (Kim 2009). However, this act should be amended to give the researcher the ability to determine the level of volunteerism and also use incentives to ensure sensitive information is collected from the participants. Gifts can play important roles in influencing the response from participants.Advertising Looking for essay on ethics? Let's see if we can help you! Get your first paper with 15% OFF Learn More This article also states that consent can be cancelled and the participants to terminate their participation and withdraw their contributions in the research at anytime. This provision identifies the possibility of having various challenges that may interfere with the ability of the participant to provide useful information to the researcher. Issues l ike diseases and attitude are not easily predictable and may occur when the research is at a crucial stage. Consequently, the researcher cannot insist that the participant must continue taking part in the research since this will be dictatorship. However, these acts should be amended to ensure participants withdraw from the research only when there is an inevitable and logical reason. Article 3.2 demands that researchers should provide all information to participants to enable them to make informed choices regarding their participation in the research. This is an ethical consideration that ensures participants are aware of what is expected of them and thus they prepare physically and psychologically for the future events regarding the research. It is important for the participants to know what the research will involve, its aims and objectives and the period the research is expected to take. This ensures the research does not interfere with other personal programmes. Article 3.3 adv ocates for the need to maintain consent throughout the study and provide participants the data relevant to the ongoing project and consent. This part plays significant roles in ensuring participants are aware of their roles in the research. In addition, it guides the researcher in maintaining essential contact with participants (Shamoo 2009). New research issues cannot be raised during the research process if they were not included in the initial stage. Therefore, this contact ensures the researcher and participants maintain the focus of the research by working within the terms and conditions agreed by both parties (Comstock 2013). However, this article should be amended to include unforeseen eventualities that may force the researcher to adjust terms of engagement. Article 3.4 highlights the need to notify the participant of any incidental events or findings that may be discovered during the study. This issue must be addressed properly to avoid raising suspicions regarding the term s of engagement agreed earlier (Kim 2009).Advertising We will write a custom essay sample on Ethical Research Conduct specifically for you for only $16.05 $11/page Learn More However, the researcher must conduct an elaborate review to minimise the possibilities of discovering any material or issue during the research. The presence of many discoveries during the research exposes the researcher and participants to tensions and this interferes with the outcomes of the research. Article 3.5 states that the research cannot begin unless the researcher obtains consent from the participants or their third parties. This means that the above processes must be exhausted before the study commences (Macrina 2012). This provision ensures the researcher and participants reach an agreement before they get down to work. However, this article should specify the time required to reach an agreement between the researcher and participants to avoid wasting time in unnecessary ne gotiations. Conclusion Research is a complicated activity that requires proper planning and implementation of various procedures. A research is as good as the methods and approaches employed in collecting information, analysing and presenting it. A good research can be distorted by poor recording or presentation of the data collected. In addition, a poor research cannot attain its goals no matter how well the results have been recorded or presented. Therefore, there must be logical agreements between the researcher and participants to ensure the research achieves its goals. References Comstock, G. (2013). Research Ethics: A Philosophical Guide to the Responsible  Conduct of Research. Cambridge: Cambridge University Press. Kim, S. H. (2009). Evaluation of Capacity to Consent to Treatment and Research: Best Practices in Forensic Mental Health Assessment. New York: Oxford University Press.Advertising Looking for essay on ethics? Let's see if we can help you! Get your first paper with 15% OFF Learn More Macrina, F. L. (2012). Scientific Integrity: Text and Cases in Responsible Conduct of  Research. New York: ASM Press. Shamoo, A.E. (2009). Responsible Conduct of Research. New York: Oxford University Press.

Hypertension or CVD Article Example | Topics and Well Written Essays - 250 words

Hypertension or CVD - Article Example The research findings indicates that approximately 5 percent of adolescents have coronary heart disease or its equivalents, or one or more of CHD risk factors such as smoking, hypertension, obesity and family history of early CHD (Kuklina, Yoon & Keenan, 2009). The authors then conclude that there is a high prevalence of CHD risk factors among the adolescents, but this does not seem to change screening rates. Therefore, they recommend that assessment and management of cardiovascular diseases, among adults should be improved. There is a significant bias in formulating the research hypothesis because the authors make this claim, but do not support it with a single evident from a primary or secondary source. The authors should have included at least two evidences from peer-reviewed articles on the same topic to valid their hypothesis. The research methodology is not well satisfying for a study in the nursing field. Other than using secondary data to for analysis, the authors should have included data collected from primary source. One-on-one interview with young adults and physicians would have provided valid data for this study. I feel that the authors’ conclusion that screening rates have not changed despite the high risk factors for cardiovascular diseases among young adults is not well satisfying. This is because CHD risk factors such as obesity and overweight have become so evident among children and adolescents, and most government programs are currently focusing on controlling these risk fact ors to protect the young adults from contacting cardiovascular diseases and their risk factors. This article is relevant in the nursing field because it shows that an unhealthy diet, which causes obesity, is one of the risk factors for the high prevalence of cardiovascular diseases and that screening of young adults, for the risk factors, is not yet a priority. Kuklina, E, V., Yoon, P, W. & Keenan, N, L. (September 25, 2009). Prevalence of Coronary

Money and Payments Coursework Example | Topics and Well Written Essays - 250 words

Money and Payments - Coursework Example However, with electronic payment systems, commercial law uses solutions designed to transfer funds or assets electronically over long distances. For instance, hotels and banks simply swipe credit cards over ATMs or counter machines to transfer funds and verify information regarding the linked account and its holder. Technological advancements will certainly continue to lower transaction costs by reducing the steps involved with each transaction verification and user authentication protocol (Mastrianna, 2012). In addition, commercial law will grow to integrate more technological innovations in its regulations and allow for smoother transactions among financial institutions, and ultimately lower transaction expenses. The United States government can improve the accuracy of its measurements by encouraging open trade with overseas economies and a new economic incentive platform (Forrest, 2014). This incentive platform offers free cash to the public so that they can buy goods and services rather than pay for bills or invest. The government can make this cash available by lowering taxes, creating more employment opportunities, subcontracting fewer employment opportunities, stabilizing the national budget, enhancing infrastructure, and providing small commercial platforms (Forrest,

Biotransport Research Paper Example | Topics and Well Written Essays - 750 words - 1

Biotransport - Research Paper Example The model foresaw deadly values of pH (less than 6.5) in EHTs consisted of 106 cells per square centimeter. Predictions of pH slightly relied on oxygen concentration and strongly on carbon dioxide concentration and the length of diffusion path. In study conclusion, acidosis induced by hypoxia are an important factor in the mass transport problem. The limitations of Transport of critical nutrients obstruct cardiac tissue engineering. The available EHT models comprise of high-density neonatal cardiomyocytes in biopolymer hydrogel or scaffold of synthetic porous polymer. After cultivation by a bioreactor, the cardiac tissue constructs make tiny synchronous contractions like that of differentiated cardiac myofibrils. The problem that prevailed was of scaling the tissue constructs to clinical size and dead cells inside the construct. Reports emphasize on the importance of oxygen as a metabolite in cardiac tissue engineering and engineered cartilage. Reports has it that oxygen concentrations of less than 14 micro molar exist in 1mm EHT model solution and the rate of consumption of oxygen by cardiomyocyte finishes it to above zero. Laboratory data suggest that reduced oxygen does not cause cell death due to hypoxia. Acidosis initiate apoptosis. Lactate-induced acidosis of culture medium at pH 6 stimulates apoptosis in cultured cardiomyocytes. There is expectation that pH and oxygen have functions to play in tissue engineering mass transport problem. Generally, the work done was to analyze the pH gradients resulting from mass transport limitations in engineered heart tissue (EHT). Brown obtained neonatal rat ventricular myocytes (NRVM) for experiment. He noticed variations in the hypoxia response in acidification of culture medium in relation to the source and procurement method. Development of EHTs constructs succeeded Eschenhagen lab method plus some modifications. He neutralized 3.2mg/mL

Different Gaits used by Bipeds and Quadrupeds

Different Gaits used by Bipeds and Quadrupeds Gait can be defined as the manner by which an animal moves.   This essay will detail the standard gaits of bipeds and quadrupeds in addition to the underlying concepts of these gaits and examples of the animals which practice them.   There are a number of technical terms used to describe gaits which will be outlined along with the classification of various gaits. Stride is defined as a complete cycle of leg movements, i.e. a select foot being set down to the next setting of the same foot, where each foot is only lifted and set down once in each stride.   Stride is further described by stride frequency, f, the number of strides per unit time, and stride length, ÃŽ », the distance travelled in a stride.   Thus, average speed, v, of an animals gait can be defined as fÃŽ ». The duty cycle of a foot is defined as the duration the foot is on the ground as a fraction of the stride.   In most gaits, the left and right feet of a pair have approximately equal duty factors.   Generally, in bipeds, when the duty factor is greater than 0.5 the gait is a walk (both feet on the ground at some point) and when it is less than 0.5 it is a run (both feet off the ground at some point). The relative phase of a foot is defined as the time the foot is set down as a fraction of the stride.   The first foot of a stride is assigned relative phase 0 and the rest have a relative phase between 0 and 1. There are four different classifications of gaits for bipeds: walk, run, skip and hop.   The walk and run gaits have symmetrical footfalls and alternating legs swings, whereas the skip and hop gaits have asymmetrical footfalls and synchronised legs swings. Bipedal walking in humans is described as a pendulum movement of the legs with the hips scribing a circular trajectory for each step.   Humans use walking as their primary gait as it is the most highly efficient and least energy consuming gait for them.   This efficiency comes from the pendulum movement of the legs; the basic principle of a swinging pendulum is conservation of mechanical energy: as potential energy increases, kinetic energy decreases and vice versa.   This helps minimise the metabolic energy required while walking as there is not net mechanical energy, making walking a very efficient gait for humans.   (www.physicsclassroom.com) Running, a faster gait, is a almost always more energy expending that walking for all animal.   The maximum walking speed is reached, at which the walk must change to a run, when the Froude number equals 1.0.   The Froude number, Fr, is dimensionless and can be defined by where v is the velocity, g is acceleration due to gravity and l is leg length.   Humans will spontaneously switch from a walk to a run at some point between a Froude number of 0.5 and 1.0, when the walking speed becomes less energy efficient than the same running speed. Skipping and hopping gaits are not often used by humans are they are less energy efficient and more unstable than the other two.   However, there are some bipedal animals that favour the skip or hop gait.   For example, hopping (when both feet have a relative phase of 0) can be advantageous in kangaroos as the legs are powerful enough to yield sufficient air time.   Similarly, skipping (when the relative phases of one foot is 0 and the other 0.3) was the preferred gait by many astronauts on the Apollo missions as the lesser force of gravity let arise to strides with long air time, making the gait highly energy efficient. Quadruped gaits are similar to the bipedal gaits, but with more precisely defined variety.   Quadrupeds may walk by walking or ambling; run by trotting or pacing; skip by cantering or galloping; hop by bounding or pronking.   The gaits are classified by the relative phase of each foot as seen below: Most quadrupeds are not capable of all gaits due to variables in their body (e.g. leg length, knee bend, foot position, foot size, etc.) and favour certain gaits over others due to energy expenditure.   Quadrupeds generally use symmetric gaits for slower running and asymmetric gaits for faster running.   For example, a horse with increasing speed will walk, trot, canter then gallop as it becomes more energy efficient to do so.   The trot is the most common run for quadrupeds, although camels pace and wildebeests change directly from a walk to a canter.   Quadrupeds like turtles, with slow muscles, can only walk, lifting one leg up at a time to maintain balance in the remaining three feet on the ground. In conclusion, bipeds and quadrupeds move by a variety of gaits, choosing the most suitable and energy efficient. Zoe Gargulak References       Michael W. Whittle, 2007, Gait Analysis: An Introduction R. McN. Alexander, 1984, The Gaits of Bipedal and Quadrupedal Animals http://www.physicsclassroom.com/mmedia/energy/pe.cfm (accessed: 14/03/16) R. McN. Alexander, 2004, Bipedal Animals, and their Differences from Humans Hugh Tyndale-Biscoe, 2005, Life of Marsupials Alberto E. Minetti, 1998, The Biomechanics of Skipping Gaits: a Third Locomotion Paradigm? Physical Principles of Biological Processes 2 (16B), 2017, Lecture 5: Posture and Gait

Passing Essay example -- Essays Papers

Passing Nella Larsen's novel, Passing, provides an example of some of the best writing the Harlem Renaissance has to offer. Nella Larsen was one of the most promising young writer's of her time. Though she only published two novels it is clear that she was one of the most important writers of the Harlem Renaissance movement. Her career as writer probably would have lasted longer, but she was accused of plagiarizing her short story, "Sanctuary." She was eventually cleared of any wrong doing, but the accusation deeply tarnished her reputation as writer. It is truly a shame that the first African-American woman to win the Guggenheim Fellowship was forced out of writing by scandal. Before being haunted by scandal, Nella Larsen played an intricate role in the Harlem Renaissance. The Harlem Renaissance was a movement that started toward the end of World War I and lasted through the mid 1930's. It was the first notable movement of African-American writers and artists in the United States. It was given the name "Harlem Renaissance" because the movement was centered in the Harlem district in New York City. More African-American writers and poets were published during this period in the United States than ever before. Not only were African-American writers being published more, but they were also getting a great deal of recognition for their work. The body of work characteristic of this time period showed a heightened sense of racial consci...

Jig and Fixture Design

Abstract This paper proposes a design of jigs and fixtures for the mass production manufacturing of Sportsman Race Series aluminum slipper pistons (Probe Industries) that are used in the Chevrolet LS Series V8 engines. The designs of two sets of jig and fixture designs are proposed. The first set (two vee-blocks and a drill bushing) is designed for the process of drilling the wrist pin holes in the piston. The second design (two vee-blocks and a pin locator) is used in the milling of the skirts and lower form of the piston.The designs use principles of manufacturing facilities design, research on manufacturing practices and 3D modeling software (Catia) in order to optimize quality (accuracy), costs and productivity in the manufacture of such pistons. 1. Introduction 1. 1 The Piston An important mechanical component of an internal combustion engine, the piston is basically a solid part in an airtight cylinder that moves under the pressure of a fluid and transfers the force of the expa nding gas to a crankshaft through a connecting rod (The American Heritage, 2005). Pistons typically consist of a few main features.Pistons are cylindrical. The top part of the piston that comes into contact with the expanding gas is the crown. All pistons have a wrist pin hole to contain a steel wrist pin that attaches the piston to a rod that is connected to the crankshaft. The skirt of the piston is the end opposite the crown and is often milled in the sides to reduce weight. 1. 2 Selected Component (Chevrolet LS Series V8 Piston) The specific component chosen for the design project is the Sportsman Race Series aluminum slipper piston (Probe Industries) used in the Chevrolet LS Series V8 engine.The high-speed nature of a V8 engine requires pistons to have reduced weight to improve engine balancing. Unlike older pistons that were made with cast iron, this piston is made with forged aluminum alloy to reduce its weight as well as improve fatigue life. Furthermore, this specific pisto n is a slipper piston with a length of only half its diameter and has some parts milled off in order to reduce size and weight dramatically. 1. 3 Objectives, Scope, and Assumptions The aim of this design project is to design jigs and fixtures for the mass production of the aluminum slipper piston used in the Chevrolet LS Series V8 engine.The scope of the design project is limited to designing jigs and fixtures for the only two processes in the manufacture of such pistons that require jigs and fixtures, specifically the drilling of the wrist pin holes and the milling of the skirts and lower form of the piston. The design project does not account for the exact design, accuracy or efficiency of the drilling and milling machines. The strength and hardness of the materials are not considered. The time and motion in between the processes are not measured for optimization. 2. Manufacturing the Component 2. 1 Component DesignThe exact specifications and design of the piston for the Chevrole t LS Series V8 engine were taken from a manufacturer of such pistons, Probe Industries. The bore (diameter) of the piston is 4 inches and the height is 2 inches. The wrist pin hole is 0. 927 inches in diameter and centered at 1. 155 inches below the crown. The wrist pin length is 2. 5 inches, meaning that the skirt below the oil grooves is milled at each end of the wrist pin hole up to 1. 25 inches away from the center of the cylinder (Probe Industries, 2012). These dimensions are important in the milling and drilling processes in the manufacture of the piston.The image below shows the rest of the dimensions and the tolerances (calculations shown later). 2. 2 Machining Processes in Manufacture of Component After forging a solid aluminum slug into the basic shape of the piston with the desired strength and stability, the component undergoes several machining processes. The first machining process involves using a lathe or a CNC turning machine to make the base, cut out oil rings or g rooves, and drill oil holes. The second process is to drill a large hole on one side of the piston through to the other. This (wrist pin hole) is where the wrist pin is placed to attach the piston to the connecting rod.The third process is to use a milling machine to shave off material at the sides where the wrist pin hole was drilled in order to reduce the weight of the piston. The fourth machining process involves finishing with a lathe machine, wherein the crown is made into its final shape, the bottom edges of the skirt are shaped, and slots/engravings are made. 3. 3 Machining Processes Requiring Jigs and Fixtures The only processes that require jigs and fixtures are the second and third machining processes, the drilling process and milling process. The first and the fourth process use CNC turning/lathe machines and they require no jigs or fixtures.The process of drilling the wrist pin hole however requires a bushing to locate the point in the cylinder that needs to be drilled a s well as a lower vee-block (with a locator at on end) and an upper vee-block (with the bushing and a pin/screw connecting to the lower vee-block) to hold the cylinder. The process of milling requires a lower vee-block as well but with a pin that goes through the wrist pin hole to hold the piston in place in the vee-block. A second, upper vee-block is used to guide the milling machine. The upper and the lower vee-block are referenced to each other with pins. 3.Functional Analysis of Jigs and Fixtures 3. 1 Drilling Process For the drilling process, a vee-block fixture is required to hold and support the cylindrical component. The design of the vee-block includes a locator at the end of the cylinder to keep the piece from moving and to help put the cylinder/piston in the right position. To drill the hole, a bushing is required to guide the drilling machine. The bushing goes through an upside-down vee-block that is put in location by pins connecting it to the lower vee-block. Bushing f or Jig Assembly: Vee-Block for Jig Assembly: Drilling Jig Assembly:Drilling Fixture Assembly (Vee-Block): Drilling Process Jig and Fixture Assembly: 3. 2 Milling Process For the milling process, the piston must be held in the right position and orientation. A vee-block is again used to support the cylindrical piston. And a locating pin is placed in the center of the vee-block at an exact location along it in order to put the piston in the right position along the vee-block and at the right orientation (hole facing upwards) for the milling to be correct (since only the sides with the holes must be milled and only exactly below the oil rings).A thin upside-down vee-block is strapped on to the top of the cylinder and connected to the lower vee-block at an exact location (using pins or screws) in order to hold the piston in place and to keep the milling machine from milling into the oil rings. To mill the other side, the piston is simply turned over and fitted into the locator from the newly milled side. Milling Process Jig (Vee-Block): Milling Process Fixture (Vee-Block and Locating Pin): Milling Process Jig and Fixture Assembly: 4. Tolerance Calculation 4. 1 Tolerance Calculation of Jig and Fixture for Drilling Process To compute or the tolerance of the upper jig of the drilling process, the tolerances of the left and right locating pins and pin holes are computed first. The tolerances and the clearances must be just enough so that both locating pins can fit in the pin holes (in all cases including largest and smallest size of one or both pins and of one or both holes). It should be noted that the worst possible scenario is that on one side of the jig, the hole is the maximum size and the pin is the minimum size while on the other side, the hole is the minimum size and the pin is the maximum size. Given that the diameter of each pin hole in the jig is 12. mm (or 0. 5 inches); the tolerance chosen for this is plus/minus 0. 01 mm (leading to a range of 12. 69-12. 71 mm for the diameter of the hole). A clearance of 0. 05 mm is chosen, causing the largest diameter for the locating pin to be 12. 64 mm. The tolerance chosen for the locating pin is plus/minus 0. 005 mm (leading to a range of 12. 635-12. 645 mm for the diameter of the pin). In the worst case scenario, on one side, the maximum hole size would be 12. 71 mm while the minimum pin size would be 12. 635 mm (leading to a potential gap of 0. 075 mm and a left or right shift of 0. 0375 mm).In the worst case scenario for locating pins where one side has a maximum hole of 12. 71 mm and a minimum pin of 12. 635 mm and the other side of the jig has a minimum hole of 12. 69 mm and a maximum pin of 12. 645 mm, the maximum shift of 0. 0375 mm on either side would still allow the larger pin to fit in the smaller hole since there would still be a gap of 0. 0075 mm (12. 69 – 0. 0375 – 12. 645 = 0. 0075). Since the bushing is screwed on tight into the jig, there is no clearance between the bushing and the jig and thus no need to differentiate between the two pieces in terms of tolerance.The tolerances of the pins and pin holes would cause variation in the position of the drill. The worst case scenario would be if on any side, the pin hole is of maximum size (12. 71 mm) and the locating pin is of minimum diameter (12. 635 mm) leading to a potential gap of 0. 075 mm and a left or right shift of 0. 0375 mm. This shift would cause the drill (center of bushing hole) to move 0. 0375 mm in any direction from the center of the jig, and thus the final wrist pin hole would be plus/minus 0. 0375 mm from the center of the final product (50. 7625 – 50. 8375 mm from the side of the piston and 29. 025 – 29. 3775 mm from the top of the piston). This is within the product specification wherein the tolerance is plus/minus 0. 05 mm (50. 75 – 50. 85 mm from the side of the piston and 29. 29 – 29. 39 mm from the top of the piston). The positions of the loca ting pins and pin holes for the upper and lower vee-block have a tolerance of 0. 005 mm on any direction and thus cause the position of the drilled hole to be between 29. 335-29. 345 mm from the top of the piston and between 50. 795-50. 805 mm from the side of the piston (still within product specifications).The locator on the lower fixture as well as the back plate each has a tolerance of 0. 005 mm combining into a worst case shift of 0. 01 mm and would cause the position of the drill to be between 29. 33-29. 35 mm from the top of the piston (still within product specifications). All the other tolerances of the drilling assembly have no effect. 4. 2 Tolerance Calculation of Jig and Fixture for Milling Process For the milling process, the holes in the upper and lower vee-blocks for the pins that locate the upper vee-block are exactly the same as in the upper jig for the drilling process.Thus the tolerances are the same (0. 01 mm hole tolerance, 0. 05 mm clearance, and 0. 005 mm loca ting pin tolerance) and so is the worst case scenario (shift of 0. 0375 mm). Since the upper vee-block guides the milling machine with a feeler gauge of 0. 01 mm, the worst case scenario would mean that the milled section is either 0. 0375 mm too high or too low on the piston (16. 7625 – 16. 8375 mm from the top of the piston). This is within the product specification wherein the tolerance is plus/minus 0. 05 mm (16. 75 – 16. 85 mm from the top of the piston).As of the lower fixture for the milling process, the symmetrical vee-block allows the cylindrical component to remain centered without rolling even when the size of the component or the fixture varies, thus eliminating the need to set tolerances. However, the tolerance must be calculated for the locating pin that goes through the wrist pin hole since a gap here would cause milling area to move up or down from the top of the piston. The hole that was previously drilled with a diameter of 23. 55 mm is assumed to hav e a tolerance of 0. 01 mm from the drilling process.A clearance of 0. 05 mm is chosen. And the locating pin has a tolerance of 0. 005 mm, thus ranging in size from 23. 49 – 23. 5 mm. In the worst case scenario of a hole with a maximum of 23. 56 mm and a locating pin with a minimum of 23. 49 mm, the potential gap would be 0. 07 mm or a shift of 0. 035 mm up or down the cylinder. This would lead the milling machine to start milling at a point between 16. 765 – 16. 835 mm from the top of the piston. This is within product specification wherein the tolerance is plus/minus 0. 05 mm (16. 75 – 16. 85 mm from the top of the piston).The locations of all the holes and locating pins should have a tolerance of 0. 005 on any direction in order to keep within product specifications. 5. Clamp Selection and Force Calculation For the drilling process, strap clamps are applied on the fixture by using a pair of socket head cap screws on the two sides of the upside-down vee-block. The two socket head cap screws locate the upper vee-block and clamp it to the lower vee-block when holding the work piece piston in place. The diameter of the holes on lower vee-block for screw is 12. 7 mm, thus M12 size socket head cap screws are selected for clamping.The tool force direction of drilling is downward and it has a tool rotation. The strap clamps fasten the upside-down vee-block and the lower vee-block preventing the cylinder from rotational motion and horizontal motion. The tool force can be taken advantage of clamping down the work piece cylinder. According to Spaenaur (2012), the tightening torque of a screw is the product of torque-friction coefficient, nominal screw diameter, and clamping load (T = KDP). The Table 1 has shown that the M12 socket head cap screw has a minimum tensile strength of 160000 pound per inch, and its material is High Carbon Quenched Tempered.In addition, it has a production torque of 125 pound. feet.. Then search this torque data in the re lated Table 2, the clamping force is approximately 13395 pound. For the milling process, the strap clamps are applied by a pair of socket set screws on the two sides of the thin upside-down vee-block. The two socket set screws locate the upper vee-block and clamp it to the lower vee-block when holding the work piece piston in place. The diameter of the holes on lower vee-block for screw is 12. 7 mm, thus M12 size socket set screws are selected for clamping.The table 1 has shown that M12 socket set screw has a minimum tensile strength of 212000 pound per inch, and its material is also High Carbon Quenched Tempered. It has a production torque of 43 pound. feet.. It can be seen in the related table, the clamping force is approximately 4286 pound. For a drilling machine, Pirtini and Lazoglu (2005) has proved that the pressure over the work piece as the cutter moving down into the work piece with same federate remains a constant value, and additional tests have been suggested that the co nstant pressure P(f) (MPa) can be described as a function of feed rate (f) (mm/min).P (f) = 1. 5364f – 103. 06. If the feed rate of the drilling machine is 198 mm/min, then the pressure is 201. 14 MPa. The equation to calculating cutting force is F= P * A. where F is the net force between the measured force and predicted thrust force due to cutting in the thrust direction and A is the contacting area of the cutter at an instant. The force is about 87 kN with the 23. 55 mm diameter drilling hole. For milling machine, we take the piston as an example: Width of cut = 79. 3mm = 3. 122 inch Depth of cut = 19 mm = 0. 748 inch Feed rate = 19. 5 inch/min K† factor =1. 56 MRR = depth of cut x width of cut x feed rate MRR = 3. 122 x 0. 748 x 19. 5 = 45. 54 inch? /min A formula for calculating horsepower (HPC) of the milling cutter is HPC = MRR/K HPC = 45. 54 / 1. 56 = 29. 19 hp The formulas above are from the article ‘A New Milling 101: Milling Forces and Formulas’ ( Brian Hamil, 2011). One metric horsepower can be defined as the power to raise a mass of 75 kilograms against the earth's gravitational force over a distance of one meter in one second. It can be calculated that the tool force is about 21 kN. . Cost Calculation Operation| Part| Rough Volume (m? )| Drilling| Lower vee-block| 0. 00095| | Upper upside-down vee-block| 0. 00051| Milling| Lower vee-block| 0. 00082| | Thin upside-down vee-block| 0. 00023| Total Volume| | 0. 00251| Density = 7225 kg/m? Mass = 18. 13 kg = 39. 97 pound Iron Materials| Casting process| Cast iron cost (USD/lb) without machining| Machining cost(USD/lb)| Gray iron| Green sand| 0. 58 to 0. 61| 0. 07 to 0. 14| | Resin sand| 0. 65 to 0. 69| 0. 07 to 0. 14| | Shell molding| 0. 72 to 0. 76| 0. 07 to 0. 14|Ductile iron| Green sand| 0. 64 to 0. 67| 0. 07 to 0. 14| | Resin sand| 0. 71 to 0. 74| 0. 07 to 0. 14| | Shell molding| 0. 75 to 0. 79| 0. 07 to 0. 14| Gray iron with shell molding machining process is selected for the fixture. Then the total cost for the 4 vee-blocks can be calculated: (0. 74 + 0. 10) x 39. 97 = 35. 57 USD = 32. 81 AUD Items| Description| Quantity| Total Cost (AUD)| Vee-block| –| 4| 32. 81| Socket head cap screw| M12 x 60 High Tensile| 2| 5. 49| Socket set screw| M12 X 60 Grade 14. 9| 2| 3. 13| Bushing| 79 Honda CBX Bronze Swing Arm| 1| 22. 4| Locating pin| 23. 5 mm diameter| 1| 18. 87| Total Cost| | | 83. 24| Thus the total cost for our design is approximately 83. 24 AUD. It should be noted that the selling price of the final product ranges between 100-200 AUD. 7. Conclusion It can thus be concluded that in the manufacture of Sportsman Race Series aluminum slipper pistons (Probe Industries) for Chevrolet LS Series V8 engines, jig and fixture assemblies can be used for the two machining processes (drilling the wrist pin hole and milling the bottom form of the piston).The jigs and fixtures designed were basically assemblies of Vee-Blocks with a bushing for the drilling process and another assembly with a locating pin through the wrist pin hole for the milling process. The tolerances were designed in order to not exceed the tolerances in the product specifications. The clamp forces were found to be sufficient and the cost of the jig and fixture is very small compared to the profit made from the final product. The design furthermore is very simple and is thus easily modified to be integrated in a fast-moving assembly line. Therefore it can be concluded that the jig and fixture designs are appropriate. . References Hamil, B. (2011) ‘A New Milling 101: Milling Forces and Formulas’ http://www. mmsonline. com/articles/a-new-milling-101-milling-forces-and-formulas. Pirtini, M. & Lazoglu, I. (2005) Forces and hole quality in drilling International Journal of Machine Tools & Manufacture 45 (2005) 1271–1281. Spaenaur (2012) ‘Suggested Tightening Torque1 Values to Produce Corresponding Bolt Clamping Loads’. http://www. spaena ur. com/pdf/sectionD/D48. pdf 9. Appendix Table 1 http://www. torqwrench. com/Info/fasteners. php Table 2 http://www. torqwrench. com/Info/fasteners. php

Article on Letters to Alice Essays

Article on Letters to Alice Essays Article on Letters to Alice Essay Article on Letters to Alice Essay Advice to a Green-Haired Punker By HILMA WOLITZER | LETTERS TO ALICE On First Reading Jane Austen. By Fay Weldon. | he premise of Letters to Alice on First Reading Jane Austen is that literature matters in the larger scheme of things, that reading can inform and alter ones life. This slender volume is its own best argument. Billed as an epistolary novel, it is more a study of a writer (and reader) thinking aloud about art and civilization. The letters, from Aunt Fay, are addressed to an imaginary niece away at school, a green-haired punker who rebels against reading Jane Austen and who is busy writing her own novel. Letters to Alice was probably inspired by a series of instructive letters Austen sent to an actual niece on the occasion of her first attempts at novel-writing. Fay Weldon, the gifted and prolific British novelist, has a clear debt to Austen; her own fiction reveals a dry wit and is devilishly incisive in its portraiture. In this book, she refers to the City of Invention, where novelists build Houses of the Imagination and readers explore for pleasure and illumination. Here in this City of Invention, the readers come and go, by general invitation, sauntering down its leafy avenues, scurrying through its horrider slums, waving to each other across the centuries, up and down the arches of the years. Critics, we are told, are mere bus drivers here. The fictitious Miss Weldon tries to lure Alice into this metropolis, between the Road to Heaven and the Road to Hell, acknowledging the competition of the local McDonalds, of certain books with empty calories and even of Alices own nervous dread of literature. She approaches the city as both a builder and a visitor, with appropriate measures of awe and trepidation. Woven into the narrative is a kind of fiction. Aunt Fay is estranged from Alices parents, and although she hopes to become reconciled with them, she deliberately gives their daughter subversive advice and aid. In the single letter she writes to her sister, Enid, Fay defends herself. Of course I am not encouraging your daughter Alice to write a novel. Of course she should concentrate on her studies. Still, she offers her niece outrageous rewards for literary effort and does encourage rebellion against the conventions that stifle the creative spirit. Most of all she makes Alice think. She draws her attention, and ours, to the inevitable connections between art and life by alternating passages from Austens novels with the facts of her real experience. In the most moving sections she describes the conditions under which women lived in early 19th-century England. The details of domesticity, the fact of womens total financial dependence on fathers and husbands and the statistics on mortality in childbirth are equally affecting. At once there is a sense of the general tenor of the times and of the particular personal history of one writer a spinster in her parents Georgian household inventing and recording other lives at a modest round table between the hearth and the window. Miss Weldon persuasively defends Austen for excluding certain worldly concerns from her work and praises her for her moral courage and for independence of thought and expression. It is true that the world of politics and power, dissent and revolution, feature a lmost not at all, in Jane Austens novels, but this was surely from choice rather than from ignorance. The main concentration in Letters to Alice is on the life and work of Jane Austen. We witness her childhood, her evolution as a writer and even her early death from Addisons disease, which is now treatable. But this is a generous book, with a broader scope one that evokes the various joys and responsibilities of the artist and the consumer of art. It defines and celebrates their shared experience, and perhaps it should be required reading, a prerequisite for students of literature. Aunt Fay writes to Alice: Only endure! Loveless marriages turn again to loving ones; unwanted children become wanted; the study that bores you today may enlighten you tomorrow. Do not change courses in mid-stream, Alice. Do not abandon Eng. Lit. for Social Studies. Simply write your own book to counteract the danger of too much analysis; synthesize as much as you analyze, and you will yet be saved. W E can only make assumptions about Alices response to such impassioned urging. (This reader immediately sought out and read Austens lesser-known Lady Susan.) We do learn that Alice plugs away at her novel and then submits it for publication, risking painful rejection. Her aunt has prepared her for that likelihood too. The eventual commercial success of Alices book it far outsells all of Aunt Fays is reported with rueful pride. Lucky Alice, to be saved from her own inclinations toward indolence and arrogance by Miss Weldons seductive invitation to the City of Invention. For anyone withou t such a wise and loving aunt, there is this splendid little book.

Christmas Tree or Floral Preservative Recipe

Christmas Tree or Floral Preservative Recipe Christmas tree preservatives (aka Christmas tree food) and cut flower preservatives contain the same ingredients: a food source for the plant, an acidifier (making hard water more acidic which helps the plant take in water and food), and a disinfectant to prevent mold, fungi, and algae from growing. This is an easy process that takes mere minutes. Christmas Tree Preservative Ingredients 1 gallon water2 cups light corn syrup4 teaspoons chlorine bleach4 teaspoons lemon juice or vinegar (optional) How To Make Christmas Tree Food Mix the ingredients together and keep the solution in the base for the Christmas tree or vase for cut flowers. Both trees and flowers will last longer in cooler areas away from direct sunlight.Make sure the tree or flower always has water. Regularly refill the vase or the base where the tree sits. In addition, you may wish to spritz the tree or flowers periodically with water from a spray bottle.You can store the solution for four to five  days at room temperature in a closed container, or two weeks refrigerated. Tips Do not drink! If you plan on making enough tree or cut flower preservative to store, label your container and keep it out of reach of children and pets.Bleach and vinegar produce toxic vapors when mixed. If you add vinegar or lemon juice, add it to the water rather than mix it directly with the bleach. Its okay to use bleach without the lemon juice or vinegar if this worries you.If you dont have corn syrup, you can substitute 4 teaspoons of sugar, dissolved in the water. Some people add a penny to a sugar solution so that the copper can act as a fungicide and acidifier.Another common option is to substitute a can of acidic soft drink, like Sprite or 7-Up, instead of the corn syrup and lemon juice. Just add a can of (non-diet) soft drink to a gallon of water, with a splash of bleach.For flowers, youll probably want to cut the recipe to 1 quart water, 1/2 c. corn syrup, 1 tsp. bleach, 1 tsp. lemon juice.

Illegal immigrant Essay Example | Topics and Well Written Essays - 750 words

Illegal immigrant - Essay Example With the downfall of the United States economy, finding jobs has become a difficult and almost impossible task for many people. Many businesses are unable to afford to take on new workers, or potential employees are either under-qualified or overqualified. Illegal immigrants, on the other hand, are finding no problems whatsoever in obtaining employment, finding the few jobs that are willing to pay employees regardless of their citizenship. Since these immigrants are illegal, they are either using fake identification cards to get their job or are else being paid under the table, and therefore are not contributing to state or federal taxes. If a legal resident of this country were in that job, the money they would make would be going to taxes, which is part of being an American. These taxes also help the state of the economy. Furthermore, when these illegal immigrants take on these jobs, they are taking away job opportunities for people that legally have a right to be working in this c ountry. Numerous news broadcasts have revealed that many places are hiring illegally, despite the fact that there are many legal people in this country who need a job just as bad as the person who obtained the employment illegally. Children of illegal immigrants have also shown to put a great strain on legal Americans in the school systems because of their inability to speak the dominating language of the classroom, which is English, and this can slow down the progress of the classroom. When young illegal immigrants enter this country, they usually do not know how to speak, read, or write in English. This has caused school systems to put these children in a level of immediate priority, slowing down the progress of the rest of the class so that those children can catch up. They are unable to keep up with the rest of the class, and instead of seeking help outside of the classrooms; teachers must use class time to ensure that those non-English speaking students understand what it going on. This slows down the rest of the students, and it is all for the sake of just a couple of students. Instead of learning the language of the country that they are immigrating to, they instead make it difficult for the rest of the students to learn as they attempt to grasp what they are being taught. In a few of my classes, the lessons would have to be stopped so that the non-English speakers would be given the chance to either have the information translated for them or explained in a way, usually through a combination of English and sign language, so that they may understand what is being said. Similarly, colleges have begun to pay special attention to the citizenship status of students, though not in a way that benefits legal residents. Unable to afford schooling, which is something that many people can currently relate to, illegal immigrants are given the scholarships and grants that should rightfully be given to the students that legally reside in this country. Many American college-hopefuls have found it to be increasingly difficult to obtain the money they need to attend school because someone else is receiving it. More often than not, that someone else is illegal and should not be receiving government funds. Finally, illegal immigrants are depleting the resources and opportunities that are reserved for legal residents. Some of

Annotade Bibliography on IQ Annotated Example | Topics and Well Written Essays - 250 words

Annotade on IQ - Annotated Bibliography Example Catherine Zentile. What IQ Tests Cant Tell You. Science Articles: The Naked Scientists: Science Radio & Science Podcasts. Cambridge University. 2008. Available at http://www.thenakedscientists.com/HTML/articles/article/what-iq-tests-cannot-tell-you/. The author explains in his article that IQ changes over time. She uses a research that was carried out by Flynn in 1984 in which Flynn found out that IQ changes over generations. She also explains that In order for an I.Q. test to give an accurate score it must be standardized using a representative sample of the age group, giving the median person a score of 100. This article will provide me with information about how IQ has changed over time. The article explains how Psychologists are broadening the concept of intelligence and how to test it using different methods. The author put into context how different psychologists are improving the methods of IQ test and how they are coming up with new methods. The author borrowed information from researchers like Nadeen Kaufman, Jack Naglieri and others in explaining his points. The article will provide me with information from different psychologist on how new methods are developing and how far the broadening has gone. The author explains how the general IQ scores of a population change over time. The author uses the three graphs that was used by Flynn to explain the change in intelligence. It also explains different types of intelligence. The article provides information on IQ gain and possible causes for the Flynn Effect. The author explains different theories of intelligence. The author found out there is no standard definition of intelligence in his research. The author researched the information from different theories by different people. The article will assist me in my literature review by providing information on different theories of intelligence. In this book, the author argues that there are several methods of measuring human IQ and