M-CHAT IN THE FIGHT AGAINST ASD Essays - Psychology, Psychiatry

M-CHAT IN THE FIGHT AGAINST ASD Author's Name Institutional Affiliation Autism Spe ctrum Disorder (ASD) is a conditio n that is identified by anti-socialism or just abnormal socialisation, display of behaviours that are stereotypical, repetition in words and actions and general lagging behind of the brain among the children (Mayes, Black Tierney, 2013) . One cannot easily identify this defect in young infants for it can be easily mistaken for a mental delay in growth. However, in the later stages of development, if the mind tends to lag as previously noted and repetition of behaviours and even words spoken, there is the need for screening for identification for ASD in order for early treatment (Matson, Kozlowski, Fitzgerald Sipes, 2013) . It is among the neurodevelopmental disorders better termed as Persuasive Developmental Disorders (PDD). These diseases do not interfere with the physical state but rather the mental; examples of similar diseases are childhood disintegrative disorder, Asperger's disorders among muc h more that affect the child like the ASD. Its most definite signs begin to be noticed when a child clocks the age of about 2-3 years but in rare cases, it is possibly identified by 18 months. Parents who identify children with this disorder are strongly advised to report the matter to a medical practitioner as early as possible for early treatment can make it go away as soon as the treatment commences. Possible symptoms include pretending play (though this should be reinforced with other characteristics because not all children who pretend play suffer from autism, others undergo anxiety or loneliness.), proto-declarative pointing and monitoring of gaze for abnormally long periods. Pretend play begins to be noticed at the age of 12-15 months where the child is observed doing strange things like it is not alone. Protodeclarative pointing, however, is noticed at about 9-14 months of age and is one of the most crucial pointers towards autism taking form; this is why the most suitable age for autism screening is 18 months because all the symptoms can be evident for easy identification. The most recent creation of CHAT has greatly aided in the identification of this disease. This " Checklist for Autism in Toddlers " (CHAT) was created to be able to diagnose ASD based on the reports that parents would bring forward with the help of CHAT (Mayes, Calhoun et al., 2009) . It comprises of 14 questions involving the child that the parent should answer, these questions are divided into section A and B. Section A basically asks about the normal behaviours the children with autism display and it comprises of nine questions. The parents are asked how the child conducts itself in matters concerning tumble play, its functional play, if the child displays proto-declarative pointing and if signs of roughness have been noted. This first section will try to determine whether the boy is compliant with it or not (Ravi, Chandrasekaran, Ka ttimani Subramanian, 2016) . Section B with the remaining five questions is for the medical practitioner to answer basing the answers on his personal observation of the child. Autism can be identified by the way the child gazes at objects, how the child keeps itself busy (pretend play), how it socializes with those around or those who come to interact with it and eventually the practitioner will gauge his answers with that of the parent thereby coming to a conclusion based on the questionnaire. These questions take roughly 15 minutes and by the end, the diagnosis is arrived at, this makes it convenient for use even at schools and other places children come to interact. Some children may pass some questions but fail in others, this is normally carefully looked at and if the child has failed in some important areas like proto-declarative pointing or developmental delays noted, the screening is done once again to minimise chances of error (Mayeset al., 2013) . With the assistance of CHAT, a sample of about 16,000 children was compiled and scrutinised and from that 10 children were found to have autism that were slightly above 3 years but not more than 4 years of age. There are two levels of autism screening that aid in the diagnosis. Level

Mount Wilson Observatory

Mount Wilson Observatory High in the San Gabriel mountains, north of the busy Los Angeles basin, the telescopes at the Mount Wilson Observatory have been watching the skies for more than a century. Through its venerable instruments, astronomers have made discoveries that have changed humanitys understanding of the universe. Fast Facts: Mount Wilson Observatory Mount Wilson Observatory has four telescopes, three solar towers, and four interferometer arrays. The largest telescope is the 100-inch Hooker Telescope.One of the most important discoveries made at Mount Wilson in its early years was by Edwin P. Hubble. He found that the Andromeda Nebula is actually a separate galaxy.The CHARA Array on Mount Wilson was used in 2013 to detect starspots on the star Zeta Andromedae, and in 2007, it made the first measurement of the angular diameter of a planet around another star. Today, Mount Wilson remains one of the premier observatories in the world, despite the incursions of light pollution that threaten its clear views of the sky. It is run by the Mount Wilson Institute, which took over the administration of the observatory after Carnegie Institution for Science planned to shut it down in 1984. The site has been kept open and running again since the mid-1990s. Mount Wilson and Observatory ridge aerial photo. Doc Searls, CC BY 2.0   History of Mount Wilson Observatory Mount Wilson Observatory was built on the 1,740-meter tall Mount Wilson (named for the early settler Benjamin Wilson). It was founded by George Ellery Hale, a solar astronomer devoted to studying and understanding sunspots, and was also one of the key people involved in building telescopes in the early 20th century. He brought the 60-inch Hale reflecting telescope to Mount Wilson, followed by the 100-inch Hooker telescope. He also built a 200-inch telescope at nearby Palomar Mountain, south of Los Angeles. It was Hales work that eventually inspired Griffith J. Griffith to give money for the Griffith Observatory in Los Angeles. The observatory at Mount Wilson was originally built with funding by the Carnegie Institution of Washington. In more recent times, it has received funding from universities. It also solicits support from the public in the form of donations for the continued operation of the facilities.   The 100-inch Hooker telescope, once the largest in the world. It is still in use today. Ken Spencer, CC BY-SA 3.0   Challenges and Telescopes Building world-class telescopes atop the mountain posed a number of challenges for the observatorys founders.  Access to the mountain was limited by the rough roads and even rougher terrain. Still, a consortium of people from Harvard, University of Southern California, and Carnegie Institutions began to work on building the observatory. Two telescopes, a 40-inch Alvan Clark instrument, and a 13-inch refractor were ordered for the new site. Harvard astronomers began using the observatory in the late 1880s. Encroaching tourists and the owners of the land made things difficult, and for a time the observatory site shut down. The planned 40-inch telescope was diverted for use at the Yerkes Observatory in Illinois.   Eventually, Hale and others decided to return to Mount Wilson to build new telescopes there. Hale wanted to do stellar spectroscopy as part of new advances in astronomy. After much back-and-forth and negotiations, Hale signed a contract to lease 40 acres at the top of Mount Wilson to build an observatory. In particular, he wanted to create a solar observatory there. It took several years, but eventually, four great telescopes, including the world’s largest solar and stellar instruments, would get built on the mountain. Using those facilities, astronomers such as Edwin Hubble made significant discoveries about stars and galaxies.   The Original Mount Wilson Telescopes The Mount Wilson telescopes were behemoths to build and transport up the mountain. Since few vehicles could make the drive, Hale had to rely on horse-drawn carriages to bring up the mirrors and equipment needed. The result of all the hard work was the building of the Snow Solar Telescope, which was the first one to be installed on the mountain. Joining it was the 60-foot solar tower, and then a 150-foot solar tower. For non-solar viewing, the observatory built the 60-inch Hale Telescope, and then finally the 100-inch Hooker Telescope. The Hooker held the record for many years as the worlds largest telescope until the 200-inch was built at Palomar.   The Hale telescope being transported up to the summit of Mount Wilson. Public domain.  Ã‚   Current Instruments Mount Wilson Observatory eventually gained several solar telescopes over the years. It has also added instruments such as the Infrared Spatial Interferometer. This array gives astronomers another way to study infrared radiation from celestial objects. In addition, there are two stellar interferometers, a 61-cm telescope, and the Caltech Infrared Telescope are also in use on the mountain. In 2004, Georgia State University built an optical interferometer called the CHARA Array (named for the Center for Angular Resolution Astronomy). Its one of the most powerful instruments of its kind.   The top of the solar tower on Mount Wilson.   Dave Foc, CC BY-SA 3.0.   Each piece of the Mount Wilson Observatory collection is equipped with state-of-the-art CCD cameras, detector arrays, and spectrometers and spectrographs. All these instruments help astronomers record the observations, create images, and dissect the light that streams from distant objects in the cosmos.  In addition, to help correct for atmospheric conditions, the 60-inch telescope has been outfitted with adaptive optics that allow it to get sharper images. Notable Observations at Mount Wilson Not long after the largest telescopes were built, astronomers began flocking to use them. In particular, astronomer Edwin P. Hubble used the Hooker to peer out at distant objects that were (at the time) called spiral nebulae.  It was at Mount Wilson that he made his famous observations of Cepheid variable stars in the Andromeda nebula, and concluded that this object was really a distant and distinct galaxy. That discovery in the Andromeda Galaxy shook the foundations of astronomy. Then, a few years later, Hubble and his assistant, Milton Humason, made further observations that proved the universe is expanding. These observations formed the basis of the modern study of cosmology: the origin and evolution of the universe. Its views of the expanding universe have informed cosmologys constant search for an understanding of such events as the Big Bang.   Edwin P. Hubble, the astronomer who used the Mount Wilson 100-inch telescope to observe distant galaxies. His work led to the discovery of the expanding universe. Public domain   Mount Wilson Observatory has also been used to look for evidence of such things as dark matter, by astronomer Fritz Zwicky, and further work on the different types of stellar populations by Walter Baade. The question of dark matter has been studied by other astronomers as well, including the late Vera Rubin. Some of astronomys most prominent names have used this facility over the years, including Margaret Harwood, Alan Sandage, and many others. Its still heavily used today and allows remote access to observers from around the world.   Dr. Vera Cooper Rubin in 1970, working on measuring galaxy rotation rates. Vera Rubin Mount Wilson in the Public Eye The administration of Mount Wilson Observatory is also dedicated to public outreach and education. To that end, the 60-inch telescope is used for educational observing. The grounds of the observatory are open to visitors, and there are weekend observing sessions and tours available as the weather permits. Hollywood has used Mount Wilson for a filming location, and the world has watched several times via Webcam as the observatory was threatened by wildfires. Sources â€Å"CHARA - Home.† Center for High Angular Resolution Astronomy, www.chara.gsu.edu/.Collins, Marvin. â€Å"Benjamins Mountain.† Broadcast History, www.oldradio.com/archives/stations/LA/mtwilson1.htm.â€Å"Mount Wilson Observatory.† Atlas Obscura, Atlas Obscura, 15 Jan. 2014, www.atlasobscura.com/places/mount-wilson-observatory.â€Å"Mount Wilson Observatory.† Mount Wilson Observatory, www.mtwilson.edu/.

Ethics and corporate social responsibility Case Study

Ethics and corporate social responsibility - Case Study Example In this case, the company upholds a high level of responsibility to public and employees (Coca-Cola Company, 36). The other part focuses on offering the responsibility of employees to the company; in fact, this involves the scope of Code of Ethics that is applicable to managers and employees in the company and subsidiaries. There are orientation meetings that are held in every two years, where information regarding this Code of Ethics is offered to employees and they are expected to sign. Personal commitment of CEO to high standards of ethics Coca-Cola Company’s CEO has a high commitment to standards of ethics, whereby they are considered to be representatives of the company through their honesty, and consistency in every condition. In this case, CEO has a commitment of guiding employees in order to facilitate compliance to the Code of Ethics (Coca-Cola Company, 36). The CEO has the mandate of ensuring that managers in various departments, especially Human Resource department. Audits to ensure compliance with code Coca-Cola Company has an Internal Audit Department, which focuses on monitoring the operations and behaviors, which entail specified those that are stipulated in the Code of Ethics; thus, these audits are conducted regally in the organization annually (Coca-Cola Company, 36). Clear and logical consequences for failure to follow the code The Company has clear and logical implications of failing to comply with this Code of Ethics, whereby employees are subjected to penalties due to their misbehaviors. Moreover, there is detailed information concerning the process of punishment and it is entailed in the Code, and reviews of this Code of Ethics, which leads to necessity of making relevant alterations depending on stakeholders’ expectations. Environmental Stewardship Detailed assessment of the company’s environmental impact Coca-Cola Company has focus on being compliant with standards involves in operations that relate to supply chain, distribution channel and disposal of obsolete or broken products. In this case, this company is highly involved in recycling of bottles; in fact, this is a manifestation of their environmental stewardship (Coca-Cola Company, 50). On the other hand, obsolete products are disposed appropriately to avoid environmental pollution, besides most of these products are used to manufacture new products. Clear goals for improvement in each impact area The company has a goal of being complaint with provisions of legislation regarding the environment. In order to improve their impact area, the Company establishes procedures that facilitate employee compliance (Coca-Cola Company, 51). Therefore, the company established an obligation of their employees, whereby they are expected to comply with procedures and polices associated with environmental protection. Moreover, they are expected to give reports regarding any case of breaches to their managers and supervisors. Internal audits to ensure impro vements There are regular internal audits aimed at ensuring improvements through adaptation of objectives and principles. Therefore, continuous improvements involve activities that accomplish these objectives in regard to environment (Coca-Cola

Conflict Management - Intrapersonal, Intergroup and Interpersonal Research Paper

Conflict Management - Intrapersonal, Intergroup and Interpersonal Types of Conflicts - Research Paper Example Organizations undergo changes due to new technological, political and social developments that affect them or due to changes in the competitive force. As people may hold a different view about the change and the future direction of an organization, conflicts may arise (Mullins). Personality Clashes: Individuals' personalities differ widely due to differences in their levels of maturity, emotional stability and their behaviour. When they do not recognize or appreciate these differences, conflicts occur. Differences in the value set: Different people have different opinions, values and beliefs. When people with contradicting values and beliefs interact with each other, conflicts are likely to occur. These conflicts are often irrational and difficult to be resolved (Newstorm). Threats to status: Most individuals associate their identity with their status in society or organizations. When an individual feels that another person's acts may harm or damage his image, which in turn may affect his status, conflict is likely to arise. Differences in Perceptions: People perceive different things, issues and their environment differently. When they act as though their perception is the only reality, without attempting to understand or accept another person's view, conflicts arise (Newstorm). Conflicts are common in all organizations and occur when people fail to arrive at a consensus regarding the organizational goals or the means to achieve them (Falletta). Organizational conflicts can be classified as follows: According to most behavioural theories, people are motivated to achieve a goal either when meeting the goal results in the satisfaction of a need, or when the incentives for achieving the goal are attractive. However, this is not as simple as it seems.

Critical Reasoning and Information Analysis Essay

Critical Reasoning and Information Analysis - Essay Example The more we learn about neuroscience, the more we understand that information literacy is a fundamental aspect of the human brain (Kandel & Squire 2000), and that humans are simply more naturally adapted to understanding certain things (like personal experience) than others (like numerical data). This sheds light on why we understand the world in the way we do. Like neuroscience, information technology is a growing field that is having a growing impact on the world. Firstly, it, for the first time, gives humans a different kind of intelligence to compare ours to: we can understand ourselves by seeing how different or similar computers are when serving different functions (Schellhammer 2008). Furthermore, information technologies like the internet are giving humans a broader understanding of our identity as going past small scale, tribal allegiances, because they allow for much more communication over large ranges. This communication is incredibly important, because social understandings play an important role in critical thinking. There are many cases where one’s social or cultural atmosphere have drastic impacts on the way they understand the world. Firstly, we pay a great deal more attention to those things that happen in proximity to us: which includes both personal actions, and friends. That means that problems that are common in one’s social group, for instance, will appear disproportionately larger than a more important problem that happens to people that are unrelated to you. This bias can cloud critical thinking, and must be avoided. The problem is, however, that other ways of understanding the world (such as universal laws of logic) do not function much better. This is because we are hard-wired to pay less attention to logic than emotions, as emotions played a more important role in our evolutionary history. So while universal logic might seem important at understanding things in a globalized society, it can often be ignored.

Strain Gauge Laboratory Exercise

Strain Gauge Laboratory Exercise An investigation into the effects of electronic circuits on the accuracy of weight measurement and how these results relate to material properties Instrumentation systems are necessary in industry to provide accurate and reliable measurements of various quantities, as well as monitoring and controlling processes. In this experiment, strain gauge sensors were attached to a cantilever beam upon which a varying load was applied and the output voltage recorded in order to estimate the mass of an unknown object. This was done for four separate electrical circuits, involving potential dividers and Wheatstone bridges, to compare their respective accuracies in measuring the unknown mass. The obtained results were also used to calculate an estimate for the Youngs Modulus of the steel beam, which was found to be 46.6 GPa. This differed greatly from the expected value of 200 GPa due to the irregular thickness of the beam, which affected the calculated results for the stress and highlighted the need to reduce sources of error before and during experiments. An instrumentation system is a collection of instruments used to measure, monitor and control a process. (1) These systems are regularly used for a variety of measurements in industries including communications, defence and engineering systems. The instrumentation systems involved in these measurement processes usually comprise of a sensor and appropriate electronic circuitry to manipulate and process the signal. Utilisation of these systems in industry is rapidly increasing as they continue to increase productivity and quality through the reduction of human error in the measurements made. The strain gauge is one of the most important sensors regarding the measurement of mechanical quantities. A strain gauge is a sensor whose resistance varies with applied force. (2) The variation in length produced by the force causes a change in electrical resistivity across the gauge which can be measured and used to calculate values of stress and strain. This report investigates the effects of different electronic circuits on the accuracy of weight measurement using strain gauge sensors on a cantilever beam and a comparison between experimental and theoretical results for Youngs Modulus. The different circuits considered are: a potential divider circuit a Wheatstone bridge circuit in quarter bridge configuration a Wheatstone bridge circuit in half bridge configuration a Wheatstone bridge and amplifier circuit A cantilever beam is a beam anchored only at one end, as shown in figure 1 below. As stated in the introduction, the application of a force on the beam alters its length which subsequently changes the strain gauge resistance. This change in resistance is given by:      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (equation 1) where R is the resistance of the gauge, à ¢Ã‹â€ Ã¢â‚¬  R is the change in resistance, is the gauge factor (which is 2 throughout this experiment) and ÃŽ µ is the strain. In the potential divider set up illustrated below in figure 2, the 1.5kÃŽ © resistor is in series with the strain gauge and, as the resistance across the strain gauge varies with the load applied, the voltage across the strain gauge will also change. This voltage can be measured and used to calculate the strain on the beam. Deformation to the strain gauge through the applied force generates a very small change in resistance, causing only a very small change in voltage for the masses added. For this reason, it is more accurate to measure the change in voltage instead of the overall output voltage. This can be achieved through the use of a circuit known as a Wheatstone bridge. A Wheatstone bridge contains two simple series-parallel arrangements of resistances connected between a voltage supply terminal and ground producing zero voltage difference between the two parallel branches when balanced. (3) The arrangement of this is shown in figure 3 below: For this investigation, the bridge is arranged in two different configurations, quarter bridge and half bridge, changing the number of arms made active. The bridge is originally balanced so the resistances in the lower and upper arms of each adjacent sides are equal, giving a 0V output. Therefore, a change in resistance of one of the active arms as the beam deforms gives rise to a voltage output à ¢Ã‹â€ Ã¢â‚¬  V which can be measured through equation 2:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (equation 2) where V is the bridge excitation voltage, R is the gauge resistance, à ¢Ã‹â€ Ã¢â‚¬  R is the change in resistance and K = for a quarter bridge set up and for a half bridge set up. Equation 1 and equation 2 can then be combined to produce an equation for calculating the induced stress in the material:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (equation 3) When a load W is applied to the beam, the stress at the strain gauge at distance L is given by the equation:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (equation 4) where ÏÆ' is the surface stress, W is the applied force, L is the distance between the load and the strain gauge sensors, b is the width of the beam and t is the thickness of the beam (see figure 4). Youngs modulus can then be calculated through Hookes Law:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (equation 5) 4.1 Apparatus The experiment was conducted using the apparatus illustrated in figure 5, as well as utilising measuring equipment described below: Cantilever beam set up as shown in figure 5, with a pair of 120kÃŽ © strain gauges attached at a distance from the free end, one above the beam and one below. Cantilever beam casing containing 2 switches to alternate between the potential divider and Wheatstone bridge circuits and then, for the latter, between quarter bridge and half bridge configuration. Masses, 100g each, to vary the load applied to the free end. Circuit board with potential divider, Wheatstone bridge and amplifier circuits set up containing potentiometers and pins to allow voltage to be measured across components. Digital Multimeter to record the output voltages of the circuit, measuring with an uncertainty of  ±0.5mV for the potential divider and  ±0.05mV for the Wheatstone bridges. Vernier caliper to measure the width and thickness of the beam, as well as the distance from the strain gauges to the load, measuring with an uncertainty of  ±0.005cm. Digital scales to calculate the actual mass of the unknown object, measuring with an accuracy of  ±0.05g. 4.2 Procedure The first electric circuit to be tested was the potential divider and therefore the switch on the cantilever beam casing was set to the corresponding place. With no load applied, the voltage across the strain gauge,, was measured. The minimum weight, 100g, was then loaded onto the beam and both the total weight and voltage across the strain gauge, , were recorded. The weight was then increased in 100g increments up to a maximum of 500g with the total weight and recorded after each mass was added. Finally, the load was removed and replaced with an unknown weight for which the voltage reading was recorded. The first switch was then changed to select the Wheatstone bridge circuit, and the second switch to choose the quarter bridge configuration. With no load applied to the beam, the excitation voltage, V, for the bridge was then measured and recorded.   This circuit contained a potentiometer which was then altered to change the resistance and ensure the initial output read 0V on the multimeter. The same procedure as for the potential divider was then carried out and the results recorded for the same differentials. The second switch was then changed to select the half bridge configuration and an identical procedure to the quarter bridge was carried out. The second switch was then changed back to the quarter bridge configuration while the circuit was changed to include a differential amplifier to increase the output voltage. The circuit is shown in figure 5 below: The same method was then followed as used for the previous Wheatstone bridge without the amplifier; however, this time, the amplified voltage was measured and recorded as opposed to the actual output voltage . Finally, after all the necessary measurements using the equipment were recorded, the unknown weight and dimensions for the beam needed to be measured in order for the results outlined in the theory section to be calculated. The digital scale was used to give a value for the unknown weight while the vernier calipers were used to measure the width, b, and thickness, t, of the beam, as well as the distance between the load and the strain gauge, L. The mass, W, added and the voltmeter measurement, V, were recorded for each circuit and collected in four tables which can be found in Appendix A. The mass values were converted from g to N and graphs of the strain gauge voltage against applied load were drawn for the four circuits. The measured voltage for the unknown mass is also included alongside the appropriate tables. 5.1 Potential Divider The unknown mass gave a reading of 1.130V. 5.2 Wheatstone Bridge The unknown mass gave a reading of 0.4mV for the quarter bridge and 0.8mV for the half bridge. 5.3 Wheatstone Bridge with Differential Amplifier The amplifier circuit increased the values recorded in figure 7 by a factor of 50. The unknown mass gave a reading of 24.2mV. 5.4 Stress against strain for the beam Using the measured values from above and inputting them into equation 4 and equation 5 respectively, a graph of stress against strain can then be plotted. Referring to equation 3, the gradient of this graph then corresponds to Youngs Modulus, which is calculated to be 46.6 GPa. 5.5 Calibration Values Weight resolution is defined as the smallest increment of weight which the numeric display, in this case the voltmeter, can indicate. (4) Each circuit used during this investigation had a different weight resolution, which was calculated by measuring the initial voltage change from no load to 100g load and comparing this to the resolution of the measuring equipment: for the potential divider, this was  ±1mV, and for the other circuits this was  ±0.1mV. For example, when the voltage in the potential divider circuit increased by 1mV, the weight increased by either 100g or 200g the potential divider does not have an absolute weight resolution as multiple load values produced the same voltage reading and therefore the weight resolution is given through a range rather than a definite value. The weight resolutions increased as expected, with the potential divider providing the least accurate measurements and the quarter bridge with differential amplifier providing the most accurate measurements. These weight measurements can be used to estimate the weight of unknown mass by multiplying the recorded voltage for the unknown mass by the weight resolution calculated. This is shown in Table 1 below: Electrical Circuit Weight Resolution Estimate for unknown mass value Potential Divider 100g-200g 113g-226g Quarter Bridge 50.0g 200g Half Bridge 25.7g 205.6g Quarter Bridge with amplifier 0.994g 241.9 g The unknown mass was measured to be 236.4g using the digital scales. As can be seen from figure 1 and figure 2 from the theory section, both the potential divider and Wheatstone bridge circuits are fitted with additional resistors, 1.5kÃŽ © and 680ÃŽ © respectively. Known as current limiting resistors, these are necessary to stop the current rising above a certain value in these circuits it is necessary to limit the current to less than 10mA, calculated by dividing the source voltage of 15V by the circuit resistance of 1.5kÃŽ © (resistor) + 240ÃŽ © (strain gauges) in the potential divider circuit, giving a current of 8.6mA. This reduces any measurement errors which could arise from an increase of the strain gauges temperature through the Joule effect, where the energy of an electric current is converted into heat as it passes through a resistive material. (5) As the circuits change from potential divider through to quarter bridge with differential amplifier, the accuracy of the measured voltages increases. This can be demonstrated through the graphs in figures 7, 8 and 9 where it can be seen that the plotted values lie progressively closer to the line of best fit with the graph for the amplifier circuit, shown in figure 9, demonstrating the least deviation from the line. Although this progression agrees with the theory, the actual values obtained differ slightly from the values expected; this is shown through the estimated values of the unknown mass recorded in Table 1. This difference could be the result of a number of factors: uncertainties in the values for the 100g masses used; the fact we are assuming a point load even though the masses provide a distribution of the weight and interference. The use of an AC current produces a small magnetic field which can cause an electromotive force in any wires that are not shielded properly. This small voltage change could be picked up by the voltmeter and slightly alter the measurements. The unknown mass was measured to be 236.4g by the digital scale. The most accurate estimate calculated by an electrical circuit was 241.9g by the Wheatstone quarter bridge with differential amplifier. The possible reasons for discrepancies between values can include the limitation of the amplifier gain due to electrical noise and temperature changes in the wire. The latter can be a problem as an increase in temperature corresponds to an increase in resistance which can affect measured values. However, this error is reduced in the half bridge configuration as, with a strain gauge sensor on both the top and bottom of the bar, the effect of temperature change cancels itself out. Finally, the Youngs Modulus value obtained through this experiment is significantly outside the expected range of 190-210 GPa, at 46.6 GPa. This can mainly be attributed to irregularities in the dimensions of the steel beam used the section of the beam where the gauges were installed was slightly smaller than the rest of the beam to allow for the necessary preparation. Referring back to equation 4 in the introduction section, the inclusion of a term shows that the thickness of the beam has the greatest effect on the calculated stress, and therefore this discrepancy in values has a significant effect on the value of Youngs Modulus calculated. To achieve a value for Youngs Modulus of 200 GPa, a thickness of 0.47cm would be required. To conclude, the experiment outlined in this report was useful in demonstrating the varying levels of accuracy of measurements which can be achieved through different forms of electrical circuits, validating the expectation that weight resolution, and therefore accuracy, would increase as the circuits progressed from a potential divider to a Wheatstone quarter bridge with differential amplifier, with the latter providing the most reliable output voltage results and the highest weight resolution. However, the result obtained for the Youngs Modulus of steel, of 46.6 GPa, through the measurements recorded in this experiment, highlights how many of the variables associated with electrical circuits have large uncertainties which can lead to extreme unreliability in the data measured and consequently the final results. The findings of this experiment are statistically insignificant due to the nature of the apparatus used compared to that used in industry. However, it does effectively illustrate the importance of reducing the effect of possible sources of error before an experiment is performed, as well as taking the time to precisely measure all of the necessary results throughout, as a slight inaccuracy in one measurement can significantly affect the final values. Mass (g) Weight (N) Voltage across Strain Gauge (V) 0 0 1.128 100 0.981 1.129 200 1.962 1.129 300 2.943 1.130 400 3.924 1.130 500 4.905 1.131 Unknown 1.130 Potential Divider Wheatstone Quarter Bridge Mass (g) Weight (N) Output Voltage (mV) 100 0.981 0.2 200 1.962 0.4 300 2.943 0.6 400 3.924 0.8 500 4.905 1 Unknown 0.4 Wheatstone Half Bridge Mass (g) Weight (N) Output Voltage (mV) 100 0.981 0.3 200 1.962 0.7 300 2.943 1.1 400 3.924 1.5 500 4.905 2.0 Unknown 0.8 Wheatstone Quarter Bridge with Amplifier Mass (g) Weight (N) Amplified Voltage (mV) 100 0.981 9.8 200 1.962 19.9 300 2.943 30.1 400 3.924 40.2 500 4.905 50.3 Unknown 24.2 [1] H. Eren and C. C. Fung, Electrical Engineering Vol.II Instrumentation Systems, Perth. [2] Omega, What is a strain gauge?, [Online]. Available: http://www.omega.co.uk/prodinfo/straingauges.html. [Accessed 17 April 2016]. [3] Electronics Tutorials Staff, Wheatstone Bridge, [Online]. Available: http://www.electronics-tutorials.ws/blog/wheatstone-bridge.html. [Accessed 17 April 2016]. [4] Precision Weighing Balances, Scale and Balance Definitions in Simple Terms, [Online]. Available: http://www.scalenet.com/applications/glossary.html. [Accessed 17 April 2016]. [5] Comsol, The Joule Heating Effect, [Online]. Available: https://www.comsol.com/multiphysics/the-joule-heating-effect. [Accessed 17 April 2016]. [6] D. R. Ngwompo, Measurements Using Strain Gauge Lab Sheet, Bath, 2016.

The Birthmark :: essays research papers

Response Paper #2: 'The Birthmark'; 1. Our society tends to be obsessed with the idea of physical perfection. How does our society manifest that obsession? How is the 'Birthmark'; an early version of our modern obsession with physical perfection? Our society has many ways of manifesting its obsession with physical perfection. In our society people go to extreme lengths to achieve perfection. The 'Birthmark';, written more than a century ago, is an early version of our modern obsession with physical perfection. Society manifests its obsession with physical perfection by having surgical procedures done on daily basis. These surgeries allow for almost any cosmetic transformation. For example a person can have anything from removing a birthmark to inserting breast implants to having a tummy tuck done on their body. Society manifests their obsession with physical perfection by having these procedures done to them. These procedures enable society to achieve 'perfection';, much like Georgiana in the 'Birthmark';. In the 'Birthmark';, a story that is more than a century old Georgiana and her husband Alymar are searching for physical perfection, much like we do today. In addition they manifested their obsession with physical perfection much like we do today. Georgiana was born with a crimson birthmark in the shape of a hand. This birthmark was on her cheek. One day Georgiana discovers that this birthmark 'shocks'; her husband and he is deeply bothered by it. Georgiana finally realizes this after Alymar says 'Georgiana . . . has it ever occurred to you that the mark upon your cheek might be removed?'; After discussing the birthmark several times with her husband, a talented scientist, Georgiana decides to have it removed by him. It is never stated in full detail exactly how Alymar is going to remove this birthmark, we assume that it will be a surgical procedure. At one point in the story Georgina says to her husband 'If there be the remote possibility of it .