A Paper in Support of the Progressive Creationism Theory Research

A in Support of the Progressive Creationism Theory - Research Paper Example This particular theory is neither purely scientific or atheistic such as the atheistic evolution theory, nor purely biblical like the theistic evolution or 24-hour day theory. It aims to mediate these two frames of thought by explaining creation in a way that addresses the concerns of both though patterns. According to Dale Tooley in his paper, â€Å"Progressive Creation: An Overview†, the progressive creationism theory is increasingly becoming accepted as a viable and arguable theory for the creation and origin of the world. In contrast to young earth creation theories, it maintains that the 6 days of creation written in the bible do not necessarily refer to 24-hour days, but instead refer to â€Å"ages†. This gives way to hard scientific evidence regarding the earth's age. Some may discard this theory due to some wordings in the bible that refer to actual days, however, we must keep in mind that we cannot compare God's day with our own. As Christians recognize that Go d's knowledge is infinite and encompasses and eclipses our own, we cannot compare his understanding to ours. This is supported by the bible in the book of Mathew, 24:36. â€Å"No one knows about that day or hour, not even the angels in heaven, nor the sun, but only the father.† This particular area of the theory also allows for intraevolution, or evolution and development within a species, but does not recognize interevolution, or evolution into other species. This gives us an explanation or rationalization for the 6 day-ages of creation. Some other theories will discount this theory saying that the bible states that death is a result of sin, and therefore, would mean that there was no death for ages until Adam committed the first sin. This can be answered in a very simple statement. Man is a very unique creation. We are not just a higher form of animal but instead were created in God's image. We were given higher thinking, rationalization, and a sense of right and wrong. The refore, the weight or burden of sin only applies to us. Since animals do not have a moral compass, and are not accountable to God, we are the only creatures that are affected by sin. Therefore, death came to us as a result of our sin and disobedience, not because of anyone else. Also discussing humans as unique creatures, we must touch on the subject of evolution. We were presented with a theory concerning man's evolution from primates. Most, if not all Christians will not accept this,and for good reason. It is not about not wanting to be associated with monkeys, nor about denial of evolution, but about how the creation of man was described in the bible. If we look at it, creation of other creatures was described rather normally. There were not a lot of details that were given regarding how other creatures were created, but this is not the case with man. The bible gave details on how man was made. This indicates that our creation is unique, purposeful and special. The bible also des cribes that we were made in God's image and that life was breathed into us by God himself. This highlights just how special we are. The theory does recognize that within ages, animals can evolve and adapt, with the guidance of God. A good example of this is the abundance of different kinds of birds. Some swim, others walk, others fly. But never the less, all of them are still birds. This is not the same as the evolution of man from primates. We are not

Main Pollutants emitted by vehicle Engines Essay Example for Free

Main Pollutants emitted by vehicle Engines Essay The hydroxyl radical then reacts with nitrogen dioxide and oxidises it to nitrate ions. The superoxide ion reacts with nitrogen monoxide to form nitrate ions. NO2 + OH H+ + NO3- NO + O2- NO3- These nitrates are then either washed away or absorbed by the blocks to form stable compounds. The crystals also catalyse the reaction because the surface of the block holds together the reactants. This increases the concentration of the reactants. Figure 2: NOX removal by titanium oxide crystals. x Three-way Catalytic Converters A three-way catalytic converter oxidises carbon monoxide and hydrocarbons, and reduces the levels of nitrogen oxides. It does this by creating the right conditions for reactions of these emissions to occur. The air to fuel ratio must be carefully controlled as oxygen is needed for the reaction of carbon monoxide and hydrocarbons. Oxygen sensors are fitted in engines with a three-way catalyst. Figure 3: The three-way catalyst system. xi Three-way catalysts are designed to produce more desirable reactions and less undesirable reactions. Desirable reactions reduce the harmful emissions from the car exhaust. Carbon monoxide and hydrocarbons react with oxygen to produce carbon dioxide and water, and nitrogen oxides react with carbon monoxide to produce carbon dioxide and nitrogen. The products are already present in the Earths atmosphere. 2CO + O2 2CO2 C7H16 + 11O2 8H2O + 7CO2 2CO + 2NO 2CO2 + N2 xii Three-way catalytic converters contain the stoichiometric fuel mixture. This means that the catalysts have the right amount of oxygen to combust the fuel and react with the carbon monoxide and hydrocarbons. Three-way catalysts also contain ceria, which stores oxygen when the mixture is lean, and releases it when the mixture is rich. This gives optimum conversion of pollutants because as the carbon monoxide and hydrocarbons are absorbed onto the catalysts surface, the oxygen stored by the ceria oxidises them even if there is not enough oxygen in the air to fuel ratio. xiii The future Scientists still have problems that need to be solved to reduce harmful vehicle emissions. One problem that needs to be addressed is how to prevent harmful exhaust emissions when the catalyst is still warming up. There are several ways that this could be dealt with, including operating the catalysts at lower temperatures and also heating the catalyst before the engine is started. xiv Scientists also need to develop a system that is able to reduce nitrogen oxide emissions from diesel engines. There are several ideas on how to go about this, including using ammonia in the exhaust, but nothing has yet been developed.  http://www.nutramed.com/environment/carsepa.htm

Design of Interventional Biomedical Devices

Design of Interventional Biomedical Devices 1. Neurovascular Catheters and Engineering Design 1. Case Study 1. The following catheter found in the cathlabdigest written by Gill Laroya discusses the advancement of the design of interventional biomedical devices from an engineering perspective and how engineers enhance the design of catheters to prevent problems such as kink. The article discusses areas such as the history of biomedical devices, the materials involved, design challenges and the interface. It discusses a specific example in terms of catheters and their use. If a catheter must travel a long distance within the neurovascular anatomy, the engineer designing the product might decide to incorporate a shaft support component, such as a stainless steel braid in order to enhance the micro catheters kink resistance. The down side of incorporating the stainless steel braid is its ability to travel within tight sections and irregular shaped bends within the neurovascular system. In order to solve this problem a stainless steel coil support is added to the distal end of the catheter, the ad dition of the coil support enhances lateral flexibility and adding hoop strength to even better the kink resistance of the micro catheter. Also, the engineer can add a lubricous hydrophilic coating to the catheter to improve axial and rotational handling of the device and reduce trauma on the walls of the veins and arteries. The study shows us how we can design micro catheters to prevent problems such as kink occurring. Cathlabdigest.com. (2016). The Design of Interventional Devices: An Engineers Perspective | Cath Lab Digest. 2. Neurovascular Catheter Design The following article was posted in Medical Tubing Types by Shana Leonard on December 12, 2014. Form the article it is predicted that by 2020 the neurovascular market will reach $600 million, according to iData Research. A key factor contributing to the growth of this sector is down to the various advancements of the biomedical device. The design goal for minimally invasive surgical devices is to strive towards engineering the smallest possible outside diameter for a micro catheter device without compromising any of the performance characteristics. Designing neurovascular catheters to meet these constraints must take into account the intricate neurovascular anatomy. Mddionline.com. (2016). Key Considerations for Designing Neurovascular Microcatheters | MDDI Medical Device and Diagnostic Industry News Products and Suppliers. According to Steven W. Berhow, president of Rogers, MN-based Biomerics Advanced Catheter, he believes that upon designing neurovascular catheters they must contain the following traits; Good torque within the shaft from the proximal to distal end. Flexibility in the distal portion of the catheter. Kink Resistance. Visibility under fluoroscopy. Low Stretch. High Pressure. Good guidewire movement. These 7 traits stand as basic constraints when it comes to designing intricate, complicated neurovascular minimally invasive devices. Figure 2. Neurovascular Catheter Design.   Mddionline.com. (2016). Key Considerations for Designing Neurovascular Microcatheters | MDDI Medical Device and Diagnostic Industry News Products and Suppliers. 3. Advanced Catheters The first thing you need to know is what an advanced catheter is. So according to Bill Alexander, Director of Business Development at Biomerics Advanced Catheter, an advanced catheter is a minimally invasive medical device that typically consists of a thin walled, braid reinforced tube or shaft with multiple durometers. An advanced catheter has the ability to navigate through the neurovascular anatomy and deliver implants and devices such as coils, heart stents etc. The difference between advanced catheters and traditional catheters can be mainly seen when it comes to manufacturing the product. A little error in the materials used in an advanced catheter can lead to larger errors as the specific wall thickness requirement of an advance catheter are very strict to ensure optimal performance. Characteristics such as pushability, trackability, torqueability and kink resistance are crucial for the advanced catheter design. Traditional catheters and advanced catheters are not mutually exclusive and can be used to benefit each other and improve patient surgical results. (2016). Advanced catheters What you need to know about this growing medical device market. Figure 3 Advanced Catheters and Traditional Catheters.   (2016). Advanced catheters What you need to know about this growing medical device market. Advanced catheters have the ability to incorporate new technologies and have a more complex design than traditional catheters. 2. Human Neurovascular and Cardiovascular Anatomy 1. Cardiovascular System The cardiovascular system consists of the heart and blood vessels along with blood itself. It transports oxygen, nutrients, hormones and more and is powered by the heart. The heart consists of 2 circulatory loops, the pulmonary circulation loop and the systematic circulation loop. The pulmonary circulation transports deoxygenated blood from the right atrium and ventricle to the lungs. The systematic circulation carries oxygenated blood from the left atrium and left ventricle to all around the body. The cardiovascular system consists of blood vessels, coronary circulation (hearts own set of blood vessels), hepatic portal circulation (veins of stomach and intestines) and the blood itself (red blood cells, white blood cells, platelets and plasma). An understanding of the complex network and its physical structures are important when designing non-invasive medical devices. System, C. (2016). Cardiovascular System. InnerBody.   Figure 4 Cardiovascular System. Slideshare.net. (2016). Circulatory system PowerPoint Blood vessels are the road network by which blood transports around the body and returns back to the heart again. This intricate tiny transportation system of blood vessels has a major part to play when engineering advanced catheters and ensuring problems such as kinking dont occur. 2. Structure and Functions of Blood Vessels Blood vessels consist of arteries and veins. Arteries bring blood away from the heart. As the arteries are brought away from the heart they eventually become smaller and are broken down to the smallest arteries called arterioles which further branch into capillaries where gases and nutrients are excreted or exchanged. Veins have a larger structure and bring blood back to the heart again. As can be seen below in figure 4, the cardiovascular circuit can be seen where two main circulatory systems occur. The pulmonary circulatory system and systematic circulatory system. Each providing their own different structural differences that engineers must take into account when designing minimally invasive medical devices. Philschatz.com. (2016). Structure and Function of Blood Vessels  · Anatomy and Physiology. Figure 5 Structure of Blood Vessels. ] Philschatz.com. (2016). The structure of blood vessels can be seen below. The artery and the veins vary in thickness as can be seen from the micrograph in figure 6. From figure 5, it can be seen that Arteries have a thicker Tunica media than Veins but veins have a larger tunica externa than arteries. Figure 6 Arteries vs Veins Structural differences. Philschatz.com. (2016).  Ã‚   Figure 7 Micrograph showing the relevant difference in thickness. Philschatz.com. (2016). As can be seen in figure 6 and 5, vein walls are considerably thinner than Artery walls meaning veins withstand a much lower pressure of blood passing through them. Table 1 Appearance of Arteries and Veins. Philschatz.com. (2016). Arteries Veins General Appearance Thick walls, small lumen Rounded appearance Thin walls, large lumen Flattened appearance Conor Patrick Goold, DME4. 7 3. Shapes of Catheters in the Neurovascular Anatomy 1. Guide Catheters and shapes in the Neurovascular system. The following is an example of a Stryker neurovascular catheter called the DAC catheter. From figure 8, it can be seen that the DAC catheter accesses the distal neurovasculature. It achieves this by providing enhanced stability through a braided shaft and this in turn also provides resistance to ovulation. Preventing shapes such as snaking and reducing friction against the blood vessel walls. Stryker.com. (2016). Neurovascular Intervention DACâ„ ¢ Catheter: Stryker. Figure 8 Catheters, Shapes and Uses. Stryker.com. (2016). Neurovascular Intervention DACâ„ ¢ Catheter: Stryker. 2. Neurovascular Catheters in the Brain. The following images are obtained through a technique that requires the use of a minimally invasive advanced neurovascular catheter. What these images do is they give a visual understanding of the intricate nature in which the catheters must travel within the cardio vascular system. To do this the catheter is guided under x-ray guidance through neurovascular and cardiovascular system. The catheter for this procedure is usually brought to a blood vessel located in the neck and a non-ionic x-ray contrast agent is injected into the blood vessels which then in turn travels through to the brain. Prior to this procedure the catheter is then removed through the groin and the bleeding is stopped through direct manual compression or by using a vascular closure device. Neuroangio.org. (2016). Introductory Brain Angiography | neuroangio.org. Figure 9 ICA Internal Carotid Artery. Neuroangio.org. (2016). Introductory Brain Angiography | neuroangio.org. In order to reach such distances in the neurovascular system, many advanced catheters are used to travel so far. The deployment of a large support catheter through the groin goes first and then a variation of other smaller catheters are deployed through the larger catheter in order to reach the required location and deploy medical devices such as coils and stents. Figure 10. CT scan of Brain. Neuroangio.org. (2016). Introductory Brain Angiography | neuroangio.org. 3. Neurovascular Catheters in the heart. Figure 11 shows the placement of a pacemaker into the heart by the deployment from a minimally invasive advanced catheter. The catheter enters the body through the collar bone on the left hand side of the heart and enters through the veins to place an electronic or mechanical pacemaker into the heart to overcome heart problems such as tachyarrhythmias, which occurs when your heart beats too fast or bradyarrhythmias, which occurs when your heart beats too slow. System, C. (2016). Cardiovascular System. Figure 11 Advanced Catheters in the Heart. System, C. (2016). Cardiovascular System. From figure 11, the C shaped position of the catheter can be seen. A number of issues can occur from an engineering perspective when a catheter must bend into the shape of a C. Kinking can occur at the maximum area of stress and strain. Engineers must design their advanced catheters in order to prevent kink from occurring and so a reinforcement braid is usually added to increase the hoop stresses of the catheter and the addition of this braid also provides better torqueability and pushability of the medical delivery device to allow it to bend to the required positions to deploy a pacemaker in the heart. 4. Research into Existing Test Methods 1. Simple existing Test methods The following is the most basic of test methods implemented by physicians when no Standard test method is available and time is of the essence. This method was applied when surgeons were experiences kinking in catheters when deployed into patients. In order to predetermine kink from happening the physicians used a simple bending technique to test for the kinking limit of catheters. If the catheter kinked, the unit was rendered useless, if not it was determined safe to use. This method is clearly not an optimal solution so further investigation into the kinking limit of catheters had to be researched and developed. Beamer, J. and French, G. (2016). A simple method for testing for the kinking epidural catheter. Figure 12 Simple Test Method No kink LHS and Kinked RHS. Beamer, J. and French, G. (2016). A simple method for testing for the kinking epidural catheter. 1.1 Simple existing test methods The catheter bends around the pin, having a predetermined diameter, D. The diameter can range from a number of different values, 5mm 50mm. The catheter is bent around the template and contacts the template at 2 tangential locations, to generate a curve and predetermine L = D. Figure 13 Kink resistance Test Method. Anon, (2016). 2. Guidance for Industry and FDA Staff Non-Clinical Engineering Tests and Recommended Labelling for Intravascular Stents and Associated Delivery Systems The following FDA guidelines outline the standards to abide by when dealing with stents and associated delivery systems. It details how the content and format of test data should be summarised in a report as well as detailing the test reports and test protocol procedures to carry out. For this test method, a review of the non-clinical engineering section was undertaken focusing on the section B (Stent Dimensions and Functional attributes) of the non-clinical engineering test, part 16. Part 16 gave FDA guidelines in kink resistance. The significance of outlining FDA guidelines for stents which are delivered by advanced catheters, it to prevent kink occurring when the normal body is in motion such as an elbow joint flexing and to ensure that no deformation to the stent occurs. This also applied to the stent delivery system when the physician deploying the stent into the human anatomy as the advanced catheter must be engineered to prevent kink from occurring upon deployment. The recommended outcome to prevent kink from happening, according to the FDA guidance document, is to determine the smallest radius of curvature that the stent can withstand and recover to its original shape and size. The test carried out to determine the smallest radius of curvature must replicate the area to which the stent will be deployed i.e. the femoral arteries. This recommended advice for implementing stents to the human body can be tailored towards the stent delivery systems also i.e. the advanced catheters. Therefore these guidelines will be taken into account when developing a test method to determine the kinking limit of catheters. See appendices for further detail regarding the FDA guidance documents discussed. Fda.gov. (2016). Guidance for Industry and FDA Staff Non-Clinical Engineering Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems. 3. Standards and guidelines ProtomedLabs provide a list of standards and regulations that relate to flexibility and kink resistance test methods. Information on the state of the art available testing equipment is provided such as the interventional device testing equipment (IDTE) from MSI which will be discussed further in part 4 of this section (MSI Catheter testing equipment). The ProtomedLabs provide information on flexibility kink resistance regarding applicable standards, related tests and test method descriptions. Applicable standards such as the FDA guidelines discussed in heading 2 above as well as ASTM standard guide for three point bending of balloon expandable vascular stents and stent systems which will be further discussed in section 5 of the literature review. Protomedlabs.com. (2016). Flexibility Kink Resistance Protomed Labs. 4. MSI Catheter testing equipment State of the art interventional device testing equipment (IDTE), compares tests and analyses performance catheters, quantifying the data of each catheter being tested. The PC allows for simple and repeatable tests with instantaneous feedback on design changes of the catheter. The IDTE was designed taking into account several different standards and test regulations such as ISO standard 25539-1 which covers cardiovascular implants endovascular devices and ISO 15539 Cardiovascular implants Endovascular Prostheses. The product is the most state of the art catheter testing equipment available right now and differentiates itself from the rest of the market by having the ability to test catheters in extremely realistic and challenging conditions. MSI. (2016). Catheter Testing MSI. Figure 14. IDTE Test Equipment. MSI. (2016). Catheter Testing MSI. The IDTE has a high temperature range with ambient temperatures of 50oC, a water bath with a temperature accuracy of +/- 2oC. It has auxiliary load cells of 100g and distal load cells of 1kg. It has the ability to test track force which is the force needed to advance a catheter, push efficiency which measures the amount of force being measured from the proximal end to the distal end, flexibility, torqueability a measure of the rotational response, retractability a measure of the amount of force required to withdraw a catheter and the crossability which measures the ability of a catheter to cross the abnormal narrowing of a passage in the body. The machine itself weighs 250kg with a height of 1372mm, width of 1194mm and a depth of 940mm. the output data of each tested is outputted onto a computer where numerical or graphical results can be formulated. MSI. (2016). Catheter Testing MSI. 5. Current Test Methods available to determine Kinking Point 1. ASTM F2606 Standard guide for three-point bending of balloon expandable vascular stents and stent systems The three point bending of stent system guidelines provide a test method that can be used to compare the flexibility of different advanced catheters by comparing load deflection curves and by comparison of calculated slopes of the curves. The test method uses a simple 3 point bending test. The upper single load applier and the two static load supporters as seen below in figure 14 must have a radius of 6.35mm. Another requirement of this test is that both the upper load applier and the two bottom static load supporters must be made of a material with a low friction coefficient so that they do contribute to the results outputted from carrying out this experiment. This test method can also be carried out in a bath of 37oC, which replicates the ambient body temperature and realistic conditions, if this application is necessary, the fixtures can be made from stainless steel or other materials that will not rust. Figure 15 Example of a three point bending test. YouTube. (2017). Catheter Bend Test at Anecto. This test has many benefits as it can many advanced catheters can be used with this method and it is applicable to many different products. It does not cause damage to the product prior to testing and can test the kinking limit along different material junctions. The test method ASTM F2606 uses a tensile tester to output its results to a computer in numerical or graphical form. Instron.us. (2017). ASTM F2606 Three-Point Bending Balloon Expandable Vascular Stents and Stent Systems Instron. 3. BS EN 13868 Catheters test methods for kinking of single lumen catheters and medical tubing This standard test method looks at the kinking of catheters being used for short term or long term uses. The short term use determines the kinking limit of a catheter being used less in than an hour and the long term is above an hour. The tube is defined as being kinked when the flow meter (Labelled 4 in figure 15 below) is outputting a reading 50% lower than the original reading. The original reading is read when the kink tools (Labelled 7) are either 50mm, 100mm or 200mm apart, depending on the users required starting distance. When the kinking tools are being compressed by the tensile tester (Labelled 7) the mass flow rate of the water flowing from the beakers (Labelled 2) will begin to reduce. Once the mass flow rate reduces to 50% of its original the catheter is said to be kinked and the test is complete. The results are outputted to a computer which gives numerical and graphical results. This test method is very beneficial as it is convenient, safe and fit for purpose. Difficulties may arise when using this test method when it comes to the fittings of the flow meter with the different sized catheters. As all catheters vary in sizes, the universal fitting of the flow meter may be difficult to mate with the distal/proximal ends of the various advanced catheters. See Appendices for more detail regarding BS EN 13868 kinking of single lumen catheters. European Standard, (2002). Catheters Test methods for kinking of single lumen catheters and medical tubing. BS EN 13868:2002. Figure 16 Short Term (LHS) and Long Term (RHS) Test methods for kinking single lumen catheters and medical tubings European Standard, (2002). Catheters Test methods for kinking of single lumen catheters and medical tubing. BS EN 13868:2002. 6. Proposed Mathematical Methods for Determining Optimal Test Method significant factors. 1. Analysis of Variance (ANOVA) Testing. The analysis of variance method determines if groups (related or unrelated) are statistically significant to each other. In order to carry out an ANOVA test, a hypothesis must first be determined. A hypothesis is a standard procedure about testing a claim about a property of a population. First a null hypothesis is formed. The Null hypothesis will test the significance of the hypothesis by either rejecting or failing to reject the claim of the null hypothesis. The Null hypothesis will claim that no difference exist between the population and the alternative hypothesis will claim that a difference exists between the populations. The alternative hypothesis will state that one or more of the parameters involved in a population will differ from the null hypothesis. The next step in an ANOVA test is to determine if the null hypothesis should be rejected or is it better to fail to reject the null hypothesis. In order to do so, an understanding of a type 1 and type 2 error is needed. A type 1 error is when the null hypothesis is rejected when in fact it should be accepted. The symbol ÃŽ ± is used to represent a type 1 error. A type 2 error is the mistake of failing to reject the null hypothesis when in fact it is false. The symbol to represent a type 2 error is ÃŽ ². In order to determine when the results are statistically significand and when the null hypothesis should be rejected, then p < ÃŽ ±, therefore the result is statistically significant and the null hypothesis should be rejected. If p > ÃŽ ±, then the null hypothesis should fail to be rejected and the results are statistically insignificant. Lacey, S. (2017). Mathematics for Engineers 402. 2. Analysis of Variance (ANOVA) Examples. To show how the ANOVA method can be applied to the parameters involved in determining the kinking limit of catheters and which factors attribute to the kinking limit the most i.e. which are statistically significant or insignificant, an example where an experiment was undertaken to test the effect of temperature and bar size on the UTS of a weld. The results from the experiment are show below in figure 16 and analysis of variance was carried out in order to determine the level of significance each parameter had on the strength of a weld. Lacey, S. (2017). Mathematics for Engineers 402. Figure 17 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. Figure 18 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. Figure 19 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. Figure 20 Analysis of Variance Example Dr. Sean Lacey, 2016, Mathematics for Engineers 402. 7. Material Properties of Neurovascular Catheters Advanced catheters are engineered to perform an increasing number of minimally invasive surgeries. They must be able to guide their way through the intricate pathways of the neurovascular, cardiovascular and other anatomies. In order to achieve these demands, using ultra small catheters of 0.5 mm, the design must be near perfect and material selection for this design is key. Catheters consists mainly of 3 layers, the liner, the braiding and the outer sheath. They can be made up to lengths ranging from 900mm 1200 mm. the best material for use in catheters are fluoropolymers such as PTFE and FEP due to their biocompatibility and lubricous properties. PTFE is the most lubricous polymer on the market today followed by FEP. The materials can undergo secondary processing steps such as etching and cutting, along with post extrusion expansion such as heat-shrinking. The liner layer mainly is made from PTFE for it lubricity, ability to maintain a thin wall and have a small diameter. The braid reinforcement layer is mainly made from Type 304 or 306 stainless steel. This layer increase is strength and rigidity without kinking the catheter. It increases the rigidity at the proximal end with a smaller pitch between winds and decrease rigidity at the distal end with a larger pitch between winds. This is done to provide greater torque transition from the proximal to distal tip of the catheter. The coil provides a greater kink resistance to the catheter along with reinforcing the catheters liner against ovalization by maximising the hoop stress. The outer sheath is made up of high performance materials such as Pebax, FEP, PTFE, ETFE, polyurethane, polyethylene and nylon. Mddionline.com. (2016). Think Extrusion and Beyond for Optimal Catheter Design | MDDI Medical Device and Diagnostic Industry News Products and Suppliers. Figure 21 Material layers of a Neurovascular Catheter. Mddionline.com. (2016). Think Extrusion and Beyond for Optimal Catheter Design | MDDI Medical Device and Diagnostic Industry News Products and Suppliers.

Time For A Change :: Essays Papers

Time For A Change The more that I learn about fossil fuels and their effect on the environment, the more surprised I become about the state of the world we live in. It seems that we live in a time that demands instant gratification. The problem with instant gratification is that the repercussions are seldom thought about. While millions of people think nothing of driving their cars for hours a day, the effects of decades of this behavior are already manifesting themselves around the world. This is particularly true in the United States, where mass consumption of fossil fuels are propagating serious environmental hazards. Perhaps the problem that strikes me as most frightening is the problem of acid rain. The nitrogens and sulfides in fossil fuels that we burn are wrecking serious havoc on the air we breathe. It is horrifying for me to think of rain falling that contains extremely corrosive and damaging factors. If this rain has the ability to corrode buildings, monuments and stat ues, I can only imagine how its long term effects must damage organic matter (Acid Rain, March 2005). It is also difficult to predict the future of this state. Will the problem intensify with time or will the recent slew of clear air acts and proposals have a palpable effect on the air we breathe? Have we passed the point of irreversibility or can we ameliorate the problems that have building over the last decades in the golden age of fossil fuels? Despite the looming problems at hand, I can’t help but feel optimistic about the situation. Technology has gotten us into this problem, and it could very well get us out of it. One breakthrough in technology could easily reduce the incidence of pollution in the long run. With the emergence and surprising popularity of hybrid cars (Hybrid Cars, March 2005) and all the research into alternative fuels such as hydrogen, it seems that the only thing missing is the technology itself. The market is clearly there. Hybrid cars have sold an astounding already. Also, considering the unprecedented exponential rate of technological advance in the past 100 years, it seems almost inevitable that a breakthrough is just around the corner.

Dance Elements Essay

Literal meaning of the word kathak is related to katha, the art of story-telling, â€Å"Katha Kahe So Kathaka Kahave†, which means â€Å"one who tells a story is a story-teller†. According to M. Monier Williams, Katha denotes conversation, story, speech, tale or fable. Katha also means to ‘ sing in praise’, ‘to say or inform something’. Thus, kathakars were originally a caste of story-tellers who were attached to temples in certain parts of Northern India. These kathakars used to go around the countryside narrating the stories of the Epics and other Legends. The modes employed were poetry, music and dance. All these three arts were closely inter-linked. The aim of kathaks was to educate the people in the knowledge of Gods and Mythological Legends. Historically kathak dates back to the Vedic period which are full of descriptions and stories which give us an insight into the mind of those who wrote or composed jthem. Kathak dance is evolved from religious and mythological concepts. In Ramayana period, we can see many glimpses of music and dance. The Ramayana tells the story of an ideal heroic prince Rama of Ayodhya and his devoted wife Sita. This ancient tale has been treasured and retold for countless generation in every Hindu house; they worshipped Rama as the seventh incarnation of Lord Vishnu. In Ramayana we find a mention of recitors who were specialised in story-telling. Lava and Kusha, the two brave sons of Rama rendered Ramayana in verses composed by Sage Valmiki. While reciting the stories, they also added the element of acting-Abhinaya. From that time nomadic bards who narrated the Ramayana were known as ‘Kushilavas’. As a matter of fact, the term kushilavas has been associated with dancers and actors. Likewise, many mythological stories were depicted through gestures, postures and abhinaya. The another story of Ramayana which tells us that how Ravana, the king of Lanka worshipped Lord Shiva with song and dance. Also the story of Ravana assaulting Rambha, one of the main Apsaras. According to Kapila Vatsyayan, in Ramayana, the Apsaras are the most important mythological characters who danced and performed both in heaven and earth. There are various other instances like the stories of the grand act of breaking Shiva’s bow in â€Å"Sita Swayamvar†, the evil plotting of Kaikayee, the Banishment of Rama to a fourteen-year exile, Sita’s kidnapping by Ravana and the war that ensued leading to Rama’s victory and Sita’s rescue. Thus, Ramayana is rich in incident and moral concept. We come across many references to perfomances of dances from the Mahabharata. In this period, worship and adoration of Bramha, Vishnu and Mahesh started with music and dance. Krishna is the ‘Sutradhara’ (around whom the entire Mahabharata developed) and he was an expert dancer. The Mahabharata depicts episodes of Krishna’s life that how he is adopted and raised by a family of cowherds. The stories of his childhood of stealing butter and milkmaids known as â€Å"MakhanChori†. His dance of his youth with Radha and Braj narees is known as â€Å"Rasa Lila†. His spiritual love dance with Gopis or Milkmaids by the bank of Yamuna river in moonlit night is known as â€Å"MahaRaas†. The story of â€Å"Kaliya Daman† which tells us how Krishna defeated the poisonous snake Kaliya and danced on his hoods. The story of â€Å"Govardhan Dharan† which tells us how krishna picked and hold the Govardhan mountain to protect the people of Vrindavan from heavy rain. Another important episode of Mahabharata is known as â€Å"Vastraharan†, in which Krishna saves the honour of the Pandava Queen Draupadi. The story goes that Dushasana, one of the Kaurava brothers attempted to humilate her by disrobing her. Draupadi called out to Krishna to save her and miraculously, as layer after layer of her saree was pulled, the number of sarees went on increasing. This episode is a popular theme in Kathak dance. Mahabharata also depicts the story of the five Pandava brothers who were unjustly deprived of their kingdom by their cousins, the kauravas, and of the great battle of Kurukshetra that established the victory of the Pandavas after much suffering and bloodshed. The Mahabharata also describes Krishna’s role as the Charioteer of Arjuna during the battle of Kurukshetra, and his conversation on the battlefield constitutes the text of the Bhagavad-Gita, the celebrated philosophical work. Thus, it is clear that by the time of Mahabharata, the arts of music and dance developed sufficient content, form, style to be taught in a systematic order. The training also seems to be elaborate with rules and regulations. Natyashastra is an encyclopedic work having 36 chapters and it deals with various topics such as the first 3 chapters deal with the origin of Natya, construction of theatre, Rangapooja, etc. , 4th and 5th chapters deal with the varieties of Dance. The 6th and 7th deal with Rasa and Bhava. From the 8th chapter of the 15th one, the different poses of Dance are being dealt with. The different aspects of Abhinaya are described in 15 to 22 and from 22nd to 28th describe the costumes elaborately. The chapters from 28th to 34 deal with music and musical instruments and the last two deal with the different characters and costumes. Natyashastra also describes the divine character and dance of the Nataraja, the dancing Lord Shiva who is considered the king of actors and dancers and also the supreme Lord of Dance. The moon which he adorns in his head is the symbol complete control of his senses. The serpents wound around his body is the proof of his complete control over vital life forces. His foot raised high over the wicked demon, a symbol of victory over the ego. This divine art form is performed by Shiva and his wife Goddess Parvati. The Dance performed Lord Shiva is known as â€Å"Tandava†, which depicts his violent nature as the destructor of the Universe. The Dance performed by Goddess Parvati is known as â€Å"Lasya†, in which the movements are gentle, graceful, erotic and it is also called the feminine version of Tandava. Therefore, according to Kapila Vatsyayan, Bharata attributes to dancing a divine origin, a literary and religious heritage both in thought and technique and aesthetic secular purpose. It has also been mentioned in Natyashastra, how to interpret the different moods of man accompanied by Bhava, Raga and Tal – all directed to create rasa or emotion in the spectators who are called â€Å"Rasikaas†. From the 7th and 8th century, â€Å"Sangeet† occupied a prominent place in the society. The art of sculptures also made great strides and most of the sculptures depicted various dance poses. Temples were the places of origin whereas the dancers or the priests danced in praise of the Lord enacting various mythological stories. Temples sprang up where the devotees gathered to pray to the Almighty God or hear stories about Him. The Temple connection is well established as can be seen in the art of â€Å"Kathavachakas† who carry on the tradition to this day in the North in the Temple boundaries and in open spaces. With the passage of time, in the medieval period, the Bhakti movement influenced all over India. The vast spiritual empire established by Vaishnavism in the North embraces life in its totality. The fine arts found a fuller expression by the 15th and the 16th centuries A. D. Literature, music, dance, painting and other fine arts flourished with the patronage extended by the temples, priests and devotees. In particular the Rasa Lilas in Braj and the neighbouring areas of Mathura in the North sustained the tradition that centered round Vishnu and his recognization as Krishna. The Bhakti movement inspired a whole new school of poetry, dance and music. Krishna and radha are the presiding deities of Vaishnavism and it was on the basis of Leelas of Krishna that precious and distinctive art heritage of Vaishnavism was built up. Mirabai, Surdas and Tulsidas for e. g. wrote powerful devotional verses on longing and separation, expressing the yearning of the human soul for union with God. They chosen the themes was the love of radha for krishna. Krishna Leela though brought out in high relief by Vaishnavism but it had its origin in the past and it can be traced easily to the periods of Mahabharata and Bhasa. In Braj, the Rasa lila’s developed as a combination of music, dance and narration that was used to enact the Krishna Legends – especially the Radha-Krishna idea and stories of Krishna’s youth with the gopis or milkmaids. Hence, the earliest compositions in kathak were based on the religious and stylised music of North India, notably the Dhrupad, Keertan, Hori, Dhamar, Pad and Bhajan. According to Mohan Khokar, Keertans are similar style to dhrupad, but they may, unlike the latter, also be sung in chorus. Keertan is a spiritual practice belonging to the path of Bhakti (devotion). Keertan more specifically means the chanting of sacred sounds or mantras. The Rasa Lila miracle plays of Braj were formerly staged to the accompaniment of keertan music only. Keertans were meant both for singing and dancing. Whereas Bhajans are strictly devotional songs and are in praise of deities such as Krishna, Shiva, Rama, Ganesha, Durga, etc. The songs are rendered in ragas, but improvised tunes are also freely used. Stories and episodes from scriptures, the teachings of saints and description of Gods have all been the subject of Bhajan. Bhajans of Mirabai, Tulsidas, Surdas, Kabir, the Ashtachhap poets and other composers are a part of kathak repertoire. Some of the Famous Bhajans of Mirabai is the following: â€Å"Baso more nanun mein nandlal, Mor mukut makrakrit kundal, arun tilak diyo bhal, Mohni murat – saavari surat, naina bane bisaal, Adhar sudha – ras murli rajat, ur baijanti maal. Chhudra ghantika kati tat sobhit, nupur sabad rasaal, Mira’ prabhu santan sukhdai, bhagat – bachhal gopal† With the advent of the Mughals, the Hindustani music underwent a drastic change. The stylised music absorbed the Mughal influence in a remarkable manner. The dancers moved from the temple courtyard to the palace dubar and this necessitated changes in presentation as Muslim kings could not enjoy the bhava of Bhakti Rasa. Kathak received encouragement at the hands of Nawabs and Rajas. Whereas formerly it was religious and devotional in mood and temperament, now it turned into a means of entertainment. The forms like Thumri, Dadra, Ghazal evolved and became a part of the Hindustani music. The word â€Å"Thumri† has been derived from a combination of two terms i. e. ‘thumak’ (or the chaal) and ‘rijhana’ (or to please). Thus, together meaning graceful stamping of the foot. Thumri is a verse that has Krishna and Radha or Krishna and Gopi’s as its central theme. It is essentially based on the divine romance portraying both aspects of separation and union. The last Nawab of Oudh, Wajid Ali Shah was an accomplished dancer and musician. He composed thumries in classical style and these were sung by the kathak dancers. His contemporaries and the court musicians like Kadarpiya, Akhtar Piya, Lallan Piya, Sikandar Piya and others contributed to its popularity. Although he was a muslim, he liked the Radha-Krishna themes. He himself presented a dance on the Rasa Lila which he called ‘Rahas’. His famous thumries are the following: â€Å"Babul mora nehar chhuto jaye, Chaar kahar mil, doliya uthave, Apna begana chhuto jaye. † Another Thumri: â€Å"Jab chod chale lucknow nagri, Tab hale ‘ali’ par kya guzri, Mahal mahal mein begum rove, Jab hum guzre duniya guzri. † According to PeterLamarche Manuel, Bindadin Maharaj is regarded as one of the most important figures in the development of Thumri as well as Kathak. The kathak Masters Bindadin and his brother Kalka Prasad composed Thumries that were suitable for kathak dancing. Some of the famous Thumri of Bindadin Maharaj is the following: â€Å"Mohe chhedo na, nand ki suno challa, Badi der bhai, ghar jane de mohe.

Is Foreign Aid a Blessing or Curse?

Since the time of independence Pakistan has been facing macroeconomic exertions, such as vicious circle of poverty, less utilization of available natural resources, unfavorable political circumstances that influenced domestic economy and so on. To seize the deficiency, Pakistan has had to depend greatly on financial assistance made by distant countries. Pakistan has been seeking aid since 1947 from global lenders including International Monetary Fund (IMF), Asian Development Bank (ADB) and World Bank.This financial aid poured mostly in the form of loans or debts with high interest rates. Focal of such assistance is the socio-economic development of the country. Financial assistance once taken as a blessing, appeared as to remove all the dearth of the economy. Resultantly many of the sectors started nourishing at par. Pakistan commenced its way towards developing nation but 2005s earthquake ruined Pakistan leaving its awful economy further worsen.Though foreign aid showered in the cou ntry but, in fact, it directly went to the bank accounts of few effluents and hence with the passage of time, it proved that foreign aid has become a curse instead of becoming blessing, not only perished the confidence of local people but corrupted more government officials. All the authorities here are now seeking more and more aid rather than to rely on their own available resources. Pakistan has already borrowed too much foreign aid in the form of loans and is still borrowing that has reached the historic over $60 billion.Debt burden is continuously increasing so its interest rates that worth more than the debt itself. Now the economic position is so deteriorated that for the payment of interest, Pakistan tries to get more loans. Pakistan has become now an aid addict and does not make policies to develop their economy with their own domestic resources. Officials do not pay attention for the development of the technology. They just become entirely dependent on others. Major portio n of aid particularly commodity aid is misappropriated by the concerned Government officials.Moreover, when aid is in terms of commodity such as wheat etc, which many times is provided at a very nominal price, discourages local production of that commodity because of higher cost of production within the country. This situation discourages local agricultural production. If donor country has assisted in establishing imported substitution industry then raw material for the industry will have to be imported from loan given country otherwise industry will not continue its production because particular raw material is not available locally.This causes heavy foreign exchange burden on economy. Pakistan is obtaining foreign aid for bridging gap between domestic savings and investment and also to improve balance of payments position but till now it has not been able to accomplish this task, rather both gaps are continuously increasing. Sometimes aid giving countries interfere in the defense and foreign affairs of Pakistan. That’s why it is said that there are always political strings attached to the bilateral loans. Thus this is to be reveal here that all aid is not for economic rationales but also political.Most of the politicians misallocate the aid for its appropriate concern so to raise their pay, power and prestige. Thus aid is also promoting greed and selfishness among the leaders of the realm. Pakistan was accessed as an independent nation but Pakistan is now fully dependent on the aid drug to eradicate all the absences. As soon as a new government takes office it is out to woe the US for aid, begs from the Saudis for a few crumbs and looks to countries like China for handouts. This must stop.To achieve self-respect and start to improve the lives of the impoverished masses the country needs corrective surgery. The starting point should be adopting a culture of austerity and simplicity. The President, Prime Minister, Army Chief and Chief Justice should be given homes and protocol of ordinary citizens. The vestiges of colonial days, the pomp of office must go. Leaders must present themselves as a role model of modesty rather to complex the masses by their luxurious stuff.One has only to look across the border that how people present themselves in public in simple clothes, sans jewels and accessories, where ministers don’t drive in flashy imported vehicles if a role model is needed. The next step is to generate resources by taxing all. The first step should be agriculture. There is no more favorable time than now. In the past 3 to 4 years produce price including cotton have witnesses a runaway increase and most farmers have had their incomes increase by over 400 percent in three years. Income tax is a failure in Pakistan however consumption tax can be promoted.All students going abroad for study should be required to get an NOC which would require their parents to explain the source of funds. All property purchase, vehicle purch ase and airline ticket purchase should require an NTN number. Put in place consumption taxes. For examples vehicles over 1000 cc should progressively be taxed. Measures such as the above would document the economy and bring more of the black economy into the main stream. With a corrupt bureaucracy, political elite and military this may virtually impossible. So a revolution is needed to unshackle Pakistan.

The british colonial experienc essays

The british colonial experienc essays When Christopher Columbus first landed on the island of Hispaniola, he had no concept of what his voyage had discovered. A New World; with boundless land and new frontiers for exploration. Political issues and the powerful Spain prevented England from any ventures into New World colonization. In 1584, Sir Walter Ralegh founded the first English settlement. Roanoke, Virginia, named for the countrys queen, was a disaster from the start. Poor land choice and much difficulty with the Indians led to a failed community. By 1586, when Sir Francis Drake visited Roanoke, the town was dead. No one reason for the disappearance of Roanoke can be found; some believe that the colonists may have been attacked by Indians, or suffered simply from the weather. Theorists believe that several of the occupants left to join native communities. The failure of Roanoke discouraged many Englishmen. No aristocrats were willing to subject themselves or families to famine and disease. Horror stories flooded England, and people did not want to leave. Richard Hakluyt and several others saw the New World as a chance for English advancement. Hakluyt wrote on the many positives colonization could bring to England. Hakluyt cited God, Gold and Glory to raise English nationalism and encourage New World colonization. The beginning of semi-successful English colonization did not occur until almost twenty years later with the settlement of Jamestown. Jamestown would be followed by distinctly different colonies that were founded by Englishmen as time moved on. Jamestown, Virginia was named for King James who gave the London Company a charter to settle there. In 1806, Sir Thomas Smith sailed for the New World. Only men came to Jamestown in 1806. The settlers picked a plot of land that they decided would be a perfect spot to protect against Spanish invasion. The men promptly built a fort to secure the colony. They didnt build schoolhouses or churches. The ...

Cthulhu in Pop Culture Professor Ramos Blog

Cthulhu in Pop Culture This being is everywhere in pop culture, but no one has any idea who he is. He has shown up in multiple forms of media ranging from T.V. shows and movies, to video games, and even a presidential campaign in his honor. As his presidential slogan says, â€Å"Abandon the pathetically lesser evils, and vote for the Greatest Evil.† (Olive). This greatest evil is Cthulhu from the Cthulhu Mythos made by H.P. Lovecraft. The big question is, why is Cthulhu so big in pop culture today? Cthulhu is a monster that was created by H.P. Lovecraft in 1926 and is still very relevant in the world today, but more needs to be said about him before it will make sense why a monster that is almost 100 years old is still around today. In the universe he was created in, he is a â€Å"Great Old One†¦Ã¢â‚¬  (Lovecraft). Which is what people might more commonly known as an Eldritch god. An eldritch god is a being with incomprehensible power that takes the form of a horrible monster that drives you insane just by looking at them. Cthulhu is no different from that description as he is multiple stories tall, a squid like head, tentacles around his mouth, giant wings, sharp claws, and full black eyes like volcanic rock. He also has the ability to manipulate hundreds of thousands of people with his mind at the same time, and he is so giant compared to humans that in his book he picks up two sailors with one hand, and â€Å" The sailors were devoured whole†¦Ã¢â‚¬  (Lovecraft 3). Cthulhu is horrifying and truly a being of nightmares. According to the article done by Auroch Digital â€Å"†¦ it comes down to two reasons why Cthulhu is still relevant: The ‘open source’ nature of the original Mythos means it was born within the concept of others adding their own take to it. [and] The core theme of the Mythos, that humanity is but a minor footnote in the history of Earth, speaks to us as part of our own fear and fascination with death and the concept of ‘the apocalypse’† (Digital 1). The first concept is easy to grasp. When you put work into something you start to care for it more and more as you put more work into it. This was a big part of making Cthulhu as popular as he is today, because so many people have added to him, to make him what he is today. With so many people adding things to this horrifying monster, it helps the monster live longer in multiple cultures. The second concept is the more complicated of the two, but with a bit of explaining and help from 1 of the 7 monster theories made by Jeffrey Cohen it will make a lot more sense. Monster theory is the combination of 7 theses that are used to â€Å"[Understand] cultures through the monsters they bear† (Cohen 4). All of the theses go more into depth on the reasons why a monster is created and would be enjoyed among the culture it was created in. Some of these theories apply more to different monsters then they do others. In Cthulhu’s case the theory â€Å"The monster is the harbinger of a category crisis† works the best to explaining why Cthulhu became so popular (Cohen 6). Cthulhu is a monster that is always the cause of horrible unimaginable things, causing chaos and destruction in his wake, because of this he is â€Å"’ a revolution to the very logic of meaning’† (Cohen 7). The idea of something that forces people to come to realizations of possible death and destruction are very interesting to us. Cthulhu always appears at the time of a crisis, most of the time the crisis being his fault in the first place. The way he was able to do this just never got old as people kept rewriting his story and adding to it. It made it more appealing to each culture it was rewritten by. In the end, the culture created a very real living and breathing monster that not only everyone is afraid of, but they are intrigued by. With people still adding to his stories and using him in works of their own this has caused him to show up in many different places over the past 94 years, ranging from a simple ‘hat tip’ in Lovecraft’s direction to a full on game centered around Cthulhu himself. The Cthulhu universe A.K.A. The Cthulhu Mythos can be seen referenced back as far as 1961 in the film Gorgo, but one of the earliest direct references to Cthulhu outside of his mythos is in the T.V. series â€Å"The Real Ghostbusters (1986-1991) with the episode being season 2 episode 41 ‘The Collect Call of Cthulhu’ (1987)† (Lovecraft Wiki). The recreation of Cthulhu will continue on for years as Cthulhu continues to show up in or have an influence on a multitude of other T.V. shows, films, novels, and games. Some of the more popular of things he has influenced are: The Mist, The Cabin in the Woods, The Justice League, Star Trek, DC Comics, The Witcher series, and the Fallout series. Because of Cthulhu’s appearance in all of these different places and times, he has been a big part of pop culture. People would grow up seeing and hearing works made with this monster in it that would leave people fearful but curious for more. This would cause Cthulhu to keep reappearing in more things as these people, that heard about him, made their own works with him making the cycle repeat again. Some of the more recent pop culture works he has been in and/ or influenced are: The Grim Adventures of Billy and Mandy, South Park, Supernatural, Robot Chicken, Stranger Things, Rick and Morty, Gravity Falls, The Elder Scrolls series, Resident Evil, even Grand Theft Auto V has a mask modeled after Cthulhu’s Head. The list goes on and on, and there is no way a single list can hold all of his references, there are just to many. He has been so popular recently that there has even been people trying to campaign him for the presidential election. Cthulhu is a big part of our culture because of all the things we use him in, and all of the arts he has influenced Anywhere from old radio stories he starred in, to modern films and TV shows he is heavily referenced in. He is a great monster that will continue to be rewritten to fit the fears of current society around death and the apocalypse; and continue to be used by many people do to the fact that he is open source. Both of those facts have made Cthulhu relevant in pop culture and some predictions believe that this relevance will keep him in pop culture for many years to come. Works Cited Cohen, Jeffrey Jerome. Monster Culture: Seven Theses. From Monster Theory: Reading Culture. Minneapolis: University of Minnesota Press, 1996. 3-25. â€Å"Cthulhu Mythos in Popular Culture.† The H.P. Lovecraft Wiki, lovecraft.fandom.com/wiki/Cthu lhu_Mythos_in_popular_culture. Digital, Auroch. â€Å"The Mainstreaming of Cthulhu: How a Fringe Horror Creation Became Popular.† Medium, Medium, 15 Feb. 2018, medium.com/@AurochDigital/the- mainstreaming-of-cthulhu-how-a-fringe-horror-creation-became-popular-5598dcb7795e. Lovecraft, Howard Phillips. â€Å"The Call of Cthulhu.† Weird Tales, Feb. 1928. Olive, Devil. â€Å"Cthulhu for President 2020: Vote for the Greatest Evil.† Cthulhu for America, 2015, cthulhuforamerica.com/. Accessed 7 August 2019

A Civil Rebuttal

A Civil Rebuttal Essay A Civil Rebuttal Essay Philosophy a:pursuit of wisdom. b:a search for a general understanding of values and reality by chiefly speculative rather than observational means. Through this most specific definition given to us respectively by Sir Websters dictionary, I choose in my best interest to refrain to you just what the meaning of philosophy is. I implore you to try and comprehend this matter in what exactly this word brought abrupt to us is about. The word philosophy has two definitive definitions. The first simply means to pursue, or strive for, wisdom. I beg to differ in the understanding of the fault I make in trying to gain this unprecedented knowledge. The knowledge that we as a unity try to strive for have made us, again as a unity, divides. I asked myself exactly how we have achieved civilized chaos in the search for our solutions and resolutions of the very virus it seems we have caused. I would not of course go so far as to say a civil war between the generations within this house, but moreover to express that simply by me using philosophy, it becomes not only my benefit, but a mutualism between us. Please feel more than obliged to correct me if I am incorrect (morally or politically) but are we not all philosophers ourselves? As a bakers vocation is to bake, a philosophers vocation is to think. Is it not that we all think? I was deeply saddened at your comments in the oppression and restriction to what I may or may not strive to think. As a pacifist and non- sadist, I call what you believe in as ingraining or indoctrination, whereas our own society may call it brainwashing. Our human nature gives us freedom, as does the Constitution. It guarantees us the right to life, liberty, and the pursuit of happiness. Within the refines of this home, I find it a task to see those liberties granted. Here is a few of the worlds greatest oppressors: Jim Jones, Adolph Hitler, Napoleon Bonaparte, Julius Caesar, David Koresh, and Anton Szandor LaVey. I know, as well as you, that these notorious six are among the worlds most hated. However here are a few oppressors from another standpoint: Sigmund Freud, Dr. Martin Luther King, Jr., Jesus Christ, Mahatma Ghandi, and Siddharta Guatama the Buddha. These are the exact opposite of the previously mentioned, who put an oppression into a good morality. Its not about who uses the gift, its the entirety of the users ethics. The second definition of the word philosophy aptly states that it is the desire to learn more through speculation rather than observation. Without speculation, we as a planet would be at loss. There would never have been discoveries of planets, medicinal uses, genetic finds, and behavioral studies. Lets face it, without philosophy, we would still get leeched at the doctors for the common cold. These fine discoveries were all made by philosophers. Now these philosophers were brave enough to challenge science, the government, and even the Church. Now, I am not one to stand here and say that I will believe in unholy blasphemy, but rather I feel I should receive the liberty to speak freely as long as I hold myself in a civil and adult manner. In conclusion to this essay, I must tell you that this in itself is my philosophy. I believe it was the great reformist Voltaire who says, I do not agree with a single word you say, but will fight to the death your right to say it. In some respects, I feel non-indifferent to his theory. So I beseech you to help yourselves as well as others in this house to let me speak freely of my philosophy, for the word is simply a synonym to the word think. The famous quote, I think, therefore I am. Furthermore, if we do not philosophize, we do not think. Scholars have made it known that the only relics of others are within their philosophy. For instance, GOD, Elshadai, or Adanai, is known exclusively through his philosophies. The Bible refers to creation as, . . . and GOD saw it was good. . . GOD philosophized that things were good. I know you cannot disagree with me on this reasoning, for you would be one to doubt GOD. I am trying my best to not make this about theology, but to simply keep it within one field. In short: the only people that choose .

Technology Evaluation Different Time, Same Place Essay

Technology Evaluation Different Time, Same Place - Essay Example asily transfer information between individuals in a company and could possibly reduce the efforts of working together and make completing tasks easier through the use of real time communication between many members of an organization at once. Though it could possible save time working on tasks this is not a known certainty. It is possible to search for any key word however I do not believe it would save time searching for information. Twitter helps you reach relevant peers and its’ service is supportive in helping you reach pertinent managers through the use of its real time interactions. It is a possibility that it could assist you in valuing your coworkers though it is not likely to help you achieve your performance goal unless it is something that you are supposed to communicate to members of your company. Unless it is specified in your job description it is not likely that Twitter will help you in your ultimate job responsibility. Twitters instant multi-way communication can increase a team’s productivity by making it easier for them to collaborate on a project and encouraging interaction and relationships among team members. It is not likely to enable a team to work faster unless they are a distance apart and communication among many members of an organization is necessary to complete a job. Twitter works well on both personal computer and mobile device, once it is an allowed application it also functions well within an intranet. By connecting you to others in your organization Twitter can be used as a method of real time communication. Twitter does not allow you to store files on its servers and does not integrate with other services. Twitter can assist an organization in multiple ways. Instant communication between many members or employees at one time and in real time is an invaluable tool in getting any project completed. The fact that it works on multiple platforms, any computer or mobile device with internet capabilities is all that is required,

Music Technology Coursework Example | Topics and Well Written Essays - 1000 words

Music Technology - Coursework Example +4dBu is generally found in professional level equipment such as public address systems. Finally, -85dBu indicates the level of noise floor (residual electronic noise) in the sound amplifying system. Noise floor is the measure of the lowest audible sound that can be amplified by the system. Collectively, the three levels are known as the operating line levels of an audio system (Glenn, 1998, p.731). A.2. What do the ranges of 24 dB, 89 dB and 109 dB indicate? Explain the function that each of these ranges has in an audio system? (9 marks) The range 24dB in the diagram indicates the headroom of the sound system (peak level- nominal level) = +28dBu-(+4dBu) =24dBu. According to Rossing (2002, p.168), the main function of this range is to describe the capacity of the sound amplifying system to handle loud sound peaks. For example, a sound system with a larger headroom range is often able to handle significantly louder sound peaks before the sound is distorted or broken. On the other hand , 89 dB range shown in the diagram indicates the S/N ratio (Signal to Noise ratio) of the sound amplifying system. Generally, S/N ratio refers to the difference between the nominal level of the sound system and the noise floor. When the S/N ratio is combined with the headroom, the result is known as the dynamic range assuming that there is no signal below the noise floor in the sound amplifying system (Borwick, 1980, p.45). ... gard, the dynamic range of the system function as the indicator of the difference between the electro-acoustic noise floor and the peak output level of the audio system. B. Why does the graphic refer to two different kinds of dB? Explain both types extensively using formulas for both types too. (15marks). The graphic diagram refers to the two types of dB namely the dB (SPL) and dBu scales. With regard to the dB (SPL), the primary variable measured is the sound pressure level in the audio system. This kind of dB is achieved by measuring the ratio amplified input signals using the logarithmic formula: 10  log  (P2/P1)  dB   Ã‚  where the log is assumed to base 10. (Rossing , Moore , Wheeler, 2002, p.87). The other type of dB used in the diagram is dBu which generally indicates the output of the sound amplifying system (amplitude ratios). dBu is the unit measure of the absolute value of the electrical potential of the system in volts (relative to the sound produced). The formula for this kind of dB is: 20 log10 (V/ V0) = 20 log10 (V/ 0.7746), where voltage is measured using root mean square (Glenn, 1998, p.851). ` C. About the values showed above, would you considered this to be a professional system or only a home-made-like system (e.g. cassette or vinyl) based)? Explain your choice. (5marks). According to the values given in the diagram, the system illustrated is most likely to be a professional system. For example, headroom of 24dB is capable of ensuring high fidelity sound that is only found in the professional sound amplification systems which are often comparatively more sophisticated than the normal homemade systems like those using vinyl and cassettes. Additionally, the large dynamic range indicated in the diagram is a likely suggestion that the system has a high

Design a research study regarding issue in developmental psychology Essay

Design a research study regarding issue in developmental psychology - Essay Example I am especially interested in the cases of those children who were kidnapped by someone other than a parent, and who were held for some time and structured into a â€Å"familial† relationship with their kidnapper/abuser. My research question is: What techniques do kidnappers use on kidnapped children to deconstruct and reconstruct identity and integrate them as a â€Å"family member† (however dysfunctional)? My hypothesis is: there are patterns of commonality in the techniques kidnappers use on kidnapped children to deconstruct and reconstruct self-identity and integrate them as a â€Å"family member† (however dysfunctional). The kidnapping of children by a stranger is a rare event (Gardiner). Fewer still survive months or years in captivity. It is rare but it happens. It happened to Jaycee Lee Dugard (ABC News). It happened to Shawn Hornbeck (CBS News.com). It happened to Elizabeth Smart (Netter, Stone and Friedman). They have told their stories, and surely ther e are others. I will collect data by looking at the cases mentioned, and any others I identify.

The Battle of 'Ayn Jalut (September 8, 1260) Essay

The Battle of 'Ayn Jalut (September 8, 1260) - Essay Example Jumi’u’t-Tawarikh put this battle into documentation presenting the struggles between the Mongols and the Mamluk. The events transpired in 1260, July, when both the Mamluk and the Mongol were encamped in Palestine. The author presents the Mongol as an army that considered itself unstoppable because it had conquered so many nations and territories including Damascus and Baghdad. This victory made Hulagu send envoys to Egypt to demand their surrender. Instead, Quduz responded by destroying the envoys. There were myriad assumptions as to what the Mongols could do to Egypt, but that turned the other way round and the battle led to the death of Ket Buqa Noyan, which saddened Hulagu greatly (Har-El 28). This document is a chronicle of the battle between Muslim nations that took place in the early ages. The author of the document is bringing forth the victory of the Egyptian army against the Mongols. The Mamluks of Egypt can secure themselves from the invading Mongols. The document, therefore, intends to reach the Egyptians and offer them a clear documentation of the events that took place in the struggle to defend themselves from invaders. The document also presented the prowess of the Mamluks to Halugu, who was devastated of hearing the death of his own general. The document presents various main points to its audience. The author begins by presenting the threat that was before Egypt. He proceeds to presenting the numerous conquests that the Mongols had managed to stage. The Egyptians are seen going round and round in reflection regarding the best thing to do: surrender, resist, or escape. After a lot of deliberations, they decide to face the attacks and are seen coming out strongly. The document, therefore, presents the fear before the battle and the role of courage in assisting the soldiers to conquer a much feared enemy. The society presented by the document is seen as one

Human resourse planning for Leicester city hotel Essay

Human resourse planning for Leicester city hotel - Essay Example With this need can also come the task of finding qualified workers, and dealing with the unfortunate business consequence of having issues with keeping workers on staff for whatever reason or another. With the case of Leicester City Hotel, an accurate human resource accounting will be needed in order to make the projected expansion of the hotel not only a success in the beginning stages, but secure it in order to have the continued success of the venture going into the future. In order to begin the task of planning for the future human resource needs which would inevitably come with the hotel's expansion; first and foremost what should be analyzed is the current state of the business in all forms. The Assignment and Case Study handout by Julie McCann provides a brief background of the hotel as well as its projected expansion and how much will change. Also the problems which are foreseen to arise in not only finding, but also maintaining a staff of qualified professionals who will not only make the expansion a success, but will stay on. This particular hotel, as McCann (2005 pg. 1) explains in her case study, is located in a city of moderate size, and deals with a clientele of business people during the week. During both the summer and holidays times deals with those individuals or families who are away form home on holiday. It is in this section where the author begins to assess the needs, which come up for the hotel during this time, as well as other things. The demand put on a companies service(s) is an essential part in calculating the necessary amount of staff needed for the faster-paced, higher demand times, and what kind of cut backs if any would need to occur or do occur during times of less demand. Overall, companies demand for staff goes up when demand for services goes up, and can also head downward when the demand for services begins to dwindle. In a sense it fits in with the overriding idea of the supply and demand principle. In viewing the expansion of the Hotel, as well as the impending surge in people who will come as a result, it is almost assured that a need for more staff will surely arise. What this will result in is causing a closer look to be taken when it comes to solidifying the chances of a qualified, reliable staff staying with the hotel for a longer period of time. Providing staff for any kind of establishment can be very time consuming, but needs to be done in such a way that the right amount of staff is brought on board. This in return can help make sure that whatever the needs the business has are being met in the time in which they need to be met. When you are running a business that has to operate during set business hours or is set in a specific location, it can often times prove to be challenging in finding staff which can fit in with this kind of set situation. Observing the forthcoming expansion of the hotel which, for all purposes, would ultimately result in an inevitable increase in demand for services. Any kind of inability on the part of the hiring staff in finding workers to fulfill such needs could prove to be a problem for the company in continuing to fulfill such obligations which come with any kind of expansion. Continuing from the previous paragraph, McCann (2005 pg. 1) alludes to the issue of securing quality staff, and what the hotel sees as a lack of qualified potential staff candidates coming out of such local resources as the colleges and universities. In order to best combat this problem, McCann tells the

Design a research study regarding issue in developmental psychology Essay

Design a research study regarding issue in developmental psychology - Essay Example I am especially interested in the cases of those children who were kidnapped by someone other than a parent, and who were held for some time and structured into a â€Å"familial† relationship with their kidnapper/abuser. My research question is: What techniques do kidnappers use on kidnapped children to deconstruct and reconstruct identity and integrate them as a â€Å"family member† (however dysfunctional)? My hypothesis is: there are patterns of commonality in the techniques kidnappers use on kidnapped children to deconstruct and reconstruct self-identity and integrate them as a â€Å"family member† (however dysfunctional). The kidnapping of children by a stranger is a rare event (Gardiner). Fewer still survive months or years in captivity. It is rare but it happens. It happened to Jaycee Lee Dugard (ABC News). It happened to Shawn Hornbeck (CBS News.com). It happened to Elizabeth Smart (Netter, Stone and Friedman). They have told their stories, and surely ther e are others. I will collect data by looking at the cases mentioned, and any others I identify.

Human resourse planning for Leicester city hotel Essay

Human resourse planning for Leicester city hotel - Essay Example With this need can also come the task of finding qualified workers, and dealing with the unfortunate business consequence of having issues with keeping workers on staff for whatever reason or another. With the case of Leicester City Hotel, an accurate human resource accounting will be needed in order to make the projected expansion of the hotel not only a success in the beginning stages, but secure it in order to have the continued success of the venture going into the future. In order to begin the task of planning for the future human resource needs which would inevitably come with the hotel's expansion; first and foremost what should be analyzed is the current state of the business in all forms. The Assignment and Case Study handout by Julie McCann provides a brief background of the hotel as well as its projected expansion and how much will change. Also the problems which are foreseen to arise in not only finding, but also maintaining a staff of qualified professionals who will not only make the expansion a success, but will stay on. This particular hotel, as McCann (2005 pg. 1) explains in her case study, is located in a city of moderate size, and deals with a clientele of business people during the week. During both the summer and holidays times deals with those individuals or families who are away form home on holiday. It is in this section where the author begins to assess the needs, which come up for the hotel during this time, as well as other things. The demand put on a companies service(s) is an essential part in calculating the necessary amount of staff needed for the faster-paced, higher demand times, and what kind of cut backs if any would need to occur or do occur during times of less demand. Overall, companies demand for staff goes up when demand for services goes up, and can also head downward when the demand for services begins to dwindle. In a sense it fits in with the overriding idea of the supply and demand principle. In viewing the expansion of the Hotel, as well as the impending surge in people who will come as a result, it is almost assured that a need for more staff will surely arise. What this will result in is causing a closer look to be taken when it comes to solidifying the chances of a qualified, reliable staff staying with the hotel for a longer period of time. Providing staff for any kind of establishment can be very time consuming, but needs to be done in such a way that the right amount of staff is brought on board. This in return can help make sure that whatever the needs the business has are being met in the time in which they need to be met. When you are running a business that has to operate during set business hours or is set in a specific location, it can often times prove to be challenging in finding staff which can fit in with this kind of set situation. Observing the forthcoming expansion of the hotel which, for all purposes, would ultimately result in an inevitable increase in demand for services. Any kind of inability on the part of the hiring staff in finding workers to fulfill such needs could prove to be a problem for the company in continuing to fulfill such obligations which come with any kind of expansion. Continuing from the previous paragraph, McCann (2005 pg. 1) alludes to the issue of securing quality staff, and what the hotel sees as a lack of qualified potential staff candidates coming out of such local resources as the colleges and universities. In order to best combat this problem, McCann tells the

Analysis of Ethics and Values Essay Example for Free

Analysis of Ethics and Values Essay Values are defined as things that are important and of some value for others. Values are of utmost importance while formulating vision. Importance of value is not just for individuals but organizations also emphasize greatly on its core values and even their vision is consistent with the values of the organization. All the decisions about right and wrong are based on the values that an individual or organization has. Thus it is said that values are the rules that one follows both in personal and professional life. Value shows what is right and what is wrong whereas doing what is right or wrong is determined by ethics. When one says that behave ethically, they mean behave in the right way. (Portman, 2010). By ethics we mean certain standards of conduct that shows how one should behave and fulfill the duties and responsibilities Professional Values and Ethics: Professional values and ethics refer to set of standards of conduct that supports the prestige of various professions that exist in the society. These set of principles indicate that how a particular professional group should behave in the society and what personal qualities they need to develop and in what way they are supposed to communicate at the workplace as well as with others in the society. For example for scientists moral principles involve integrity and patriotism. Justice and sincerity are the ethics for judiciary. Professional ethics become an important part of an organization because it increases the productivity of the organization as it indicates the way people should communicate with each other and the way they should carry out their responsibilities. Ethics for Military Organization Everyone agrees to the fact that integrity, honesty and moral conduct are important elements in a good human being but what people don’t agree is that these standards are applied equally for both personal and professional lives. An employee thinks that as long as his task are fulfilled, his employer should not care about his private conduct and he has all the rights to drinks, cheat take drugs or whatever he wants to do in his personal life. This may be true for the civilian sector but in the military there is different view. They do not tolerate drugs or alcohol. They do not allow sexual involvement with others in the workplace and severe punishments are given for dishonesty. Senior leaders say that for them private and public line are erased they cannot do what they want to do even in private as they answerable for the entire act that they do in private life as well. Military Ethics and Ethical Concepts: Military ethics refers to the code of conduct of military personnel while performing military activities. This concept of military ethics revolves around three sub concepts. The first concept refers to suitable behavior of individual for their profession, proper understanding of their standard mission and the assignments given to them and the right manner through which they can achieve their missions. The second concept underlines the suitable conduct of the military which is based on the fact that military members belong to a specific profession. The third concept specifies proper conduct of military members as a citizen of a free society where people are expected to respect the dignity of humans and adhering to the values of the democratic society. Professionalism Concept: Military ethics is based on complete professionalism which identifies the military members as professionals. Just as all other professionals are expected to perform their duties in a certain manner; the same military members are also required to adhere to the values and principles of the society. Conception of Owing: There are three Os on which the military ethics rely. These include; owing, ordering and to ought. Military officers are indebted to a lot of people such as country people, their families and comrades therefore they should realize that it is a selfless service. Conception of Ordering: Concept of ordering is also very important in military ethics. It is about priorities and moral structures. For example a top ranking officer knows that there is certain defect in a weapon that military requires badly, should the military officer reveal this information to the committee which is analyzing the weapon or he should withhold this information and go ahead in getting the weapon for his men. Here the question of ethics and priority comes. Conception of Obligations: This means what military members ought to do. According to military ethics, soldiers are expected to obey all the orders of the seniors promptly. But sometimes this happen that these orders raise ethical question therefore the military men are usually stuck between obeying the command or doing what is right and needs to be done.

Sources of noise in transistor

Sources of noise in transistor SOURCE OF NOISE IN TRANSISTOR FOR DIFFERENT CONFIGURATION Abstract- Here in this term paper, I am going to discuss the history of the transistors, its importance and its limitations. The term paper is on the sources of noise in transistors for different configurations. HISTORY A replica of the first working transistor. The first patent for the field-effect transistor principle was filed in Canada by Austrian-Hungarian physicist Julius Edgar Lilienfeld on October 22, 1925, but Lilienfeld did not publish any research articles about his devices. In 1934 German physicist Dr. Oskar Heil patented another field-effect transistor. On 17 November 1947 John Bardeen and Walter Brattain, at ATT Bell Labs, observed that when electrical contacts were applied to a crystal of germanium, the output power was larger than the input. William Shockley saw the potential in this and worked over the next few months greatly expanding the knowledge of semiconductors and is considered by many to be the father of the transistor. The term was coined by John R. Pierce. IMPORTANCE The transistor is considered by many to be the greatest invention of the twentieth-century, or as one of the greatest. It is the key active component in practically all modern electronics. Its importance in todays society rests on its ability to be mass produced using a highly automated process (fabrication) that achieves astonishingly low per-transistor costs. Although several companies each produce over a billion individually-packaged (known as discrete) transistors every year, the vast majority of transistors produced are in integrated circuits (often shortened to IC, microchips or simply chips) along with diodes, resistors, capacitors and other electronic components to produce complete electronic circuits. A logic gate consists of about twenty transistors whereas an advanced microprocessor, as of 2006, can use as many as 1.7 billion transistors (MOSFETs). About 60 million transistors were built this year [2002] for [each] man, woman, and child on Earth. The transistors low cost, flexibility and reliability have made it a ubiquitous device. Transistorized mechatronic circuits have replaced electromechanical devices in controlling appliances and machinery. It is often easier and cheaper to use a standard microcontroller and write a computer program to carry out a control function than to design an equivalent mechanical control function.[1] USAGE The bipolar junction transistor, or BJT, was the first transistor invented, and through the 1970s, was the most commonly used transistor. Even after MOSFETs became available, the BJT remained the transistor of choice for many analog circuits such as simple amplifiers because of their greater linearity and ease of manufacture. Desirable properties of MOSFETs, such as their utility in low-power devices, usually in the CMOS configuration, allowed them to capture nearly all market share for digital circuits; more recently MOSFETs have captured most analog and power applications as well, including modern clocked analog circuits, voltage regulators, amplifiers, power transmitters, motor drivers, etc. BJT used as an electronic switch, in grounded-emitter configuration. How a transistor works Amplifier circuit, standard common-emitter configuration. Simple circuit using a transistor. Operation graph of a transistor The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. A transistor can control its output in proportion to the input signal; this is called an amplifier. Or, the transistor can be used to turn current on or off in a circuit like an electrically controlled switch, where the amount of current is determined by other circuit elements. The two types of transistors have slight differences in how they are used in a circuit. A bipolar transistor has terminals labelled base, collector and emitter. A small current at base terminal can control or switch a much larger current between collector and emitter terminals. For a field-effect transistor, the terminals are labelled gate, source, and drain, and a voltage at the gate can control a current between source and drain. The image to the right represents a typical bipolar transistor in a circuit. Charge will flow between emitter and collector terminals depending on the current in the base. Since internally the base and emitter connections behave like a semiconductor diode, a voltage drop develops between base and emitter while the base current exists. The size of this voltage depends on the material the transistor is made from, and is referred to as VBE. Transistors are commonly used as electronic switches, for both high power applications including switched-mode power supplies and low power applications such as logic gates. It can be seen from the graph that once the base voltage reaches a certain level, shown at B, the current will no longer increase with increasing VBE and the output will be held at a fixed voltage.[dubious discuss] The transistor is then said to be saturated. Hence, values of input voltage can be chosen such that the output is either completely off, or completely on. The transistor is acting as a switch, and this type of operation is common in digital circuits where only on and off values are relevant. TRANSISTOR AS AN AMPLIFIER The above common emitter amplifier is designed so that a small change in voltage in (Vin) changes the small current through the base of the transistor and the transistors current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout. It is important that the operating parameters of the transistor are chosen and the circuit designed such that as far as possible the transistor operates within a linear portion of the graph, such as that shown between A and B, otherwise the output signal will suffer distortion. Various configurations of single transistor amplifier are possible, with some providing current gain, some voltage gain, and some both. From mobile phones to televisions, vast numbers of products include amplifiers for sound reproduction, radio transmission, and signal processing. The first discrete transistor audio amplifiers barely supplied a few hundred milliwatts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved. Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive. Some musical instrument amplifier manufacturers mix transistors and vacuum tubes in the same circuit, as some believe tubes have a distinctive sound.Prior to the development of transistors, vacuum (electron) tubes (or in the UK thermionic valves or just valves) were the main active components in electronic equipment. ADVANTAGES The key advantages that have allowed transistors to replace their vacuum tube predecessors in most applications are: I. Small size and minimal weight, allowing the development of miniaturized electronic devices. II. Highly automated manufacturing processes, resulting in low per-unit cost. III. Lower possible operating voltages, making transistors suitable for small, battery-powered applications. IV. No warm-up period for cathode heaters required after power application. V. Lower power dissipation and generally greater energy efficiency. VI. Higher reliability and greater physical ruggedness. VII. Extremely long life. Some transistorized devices produced more than 30 years ago are still in service. VIII. Complementary devices available, facilitating the design of complementary-symmetry circuits, something not possible with vacuum tubes. IX. Insensitivity to mechanical shock and vibration, thus avoiding the problem of microphonics in audio applications. [2] LIMITATIONS I. Silicon transistors do not operate at voltages higher than about 1,000 volts (SiC devices can be operated as high as 3,000 volts). In contrast, electron tubes have been developed that can be operated at tens of thousands of volts. II. High power, high frequency operation, such as used in over-the-air television broadcasting, is better achieved in electron tubes due to improved electron mobility in a vacuum. III. On average, a higher degree of amplification linearity can be achieved in electron tubes as compared to equivalent solid state devices, a characteristic that may be important in high fidelity audio reproduction. IV. Silicon transistors are much more sensitive than electron tubes to an electromagnetic pulse, such as generated by a nuclear explosion. V. Semiconductor material: germanium, silicon, gallium arsenide, silicon carbide, etc. VI. Structure: BJT, JFET, IGFET (MOSFET), IGBT, other types VII. Polarity: NPN, PNP (BJTs); N-channel, P-channel (FETs) VIII. Maximum power rating: low, medium, high IX. Maximum operating frequency: low, medium, high, radio frequency (RF), microwave (The maximum effective frequency of a transistor is denoted by the term fT, an abbreviation for frequency of transition. The frequency of transition is the frequency at which the transistor yields unity gain). X. Application: switch, general purpose, audio, high voltage, super-beta, matched pair XI. Physical packaging: through hole metal, through hole plastic, surface mount, ball grid array, power modules XII. Amplification factor hfe (transistor beta) Thus, a particular transistor may be described as: silicon, surface mount, BJT, NPN, low power, high frequency switch. The bipolar junction transistor (BJT) was the first type of transistor to be mass-produced. Bipolar transistors are so named because they conduct by using both majority and minority carriers. The three terminals of the BJT are named emitter, base and collector. Two p-n junctions exist inside a BJT: the base/emitter junction and base/collector junction. The [BJT] is useful in amplifiers because the currents at the emitter and collector are controllable by the relatively small base current. In an NPN transistor operating in the active region, the emitter-base junction is forward biased, and electrons are injected into the base region. Because the base is narrow, most of these electrons will diffuse into the reverse-biased base-collector junction and be swept into the collector; perhaps one-hundredth of the electrons will recombine in the base, which is the dominant mechanism in the base current. By controlling the number of electrons that can leave the base, the number of electrons ent ering the collector can be controlled. Unlike the FET, the BJT is a low-input-impedance device. Also, as the base-emitter voltage (Vbe) is increased the base-emitter current and hence the collector-emitter current (Ice) increase exponentially according to the Shockley diode model and the Ebers-Moll model. Because of this exponential relationship, the BJT has a higher transconductance than the FET. Bipolar transistors can be made to conduct by exposure to light, since absorption of photons in the base region generates a photocurrent that acts as a base current; the collector current is approximately beta times the photocurrent. Devices designed for this purpose have a transparent window in the package and are called phototransistors. FIELD EFFECT TRANSISTORS The field-effect transistor (FET), sometimes called a unipolar transistor, uses either electrons (in N-channel FET) or holes (in P-channel FET) for conduction. The four terminals of the FET are named source, gate, drain, and body (substrate). On most FETs, the body is connected to the source inside the package, and this will be assumed for the following description. In FETs, the drain-to-source current flows via a conducting channel that connects the source region to the drain region. The conductivity is varied by the electric field that is produced when a voltage is applied between the gate and source terminals; hence the current flowing between the drain and source is controlled by the voltage applied between the gate and source. As the gate-source voltage (Vgs) is increased, the drain-source current (Ids) increases exponentially for Vgs below threshold, and then at a roughly quadratic rate (I_{ds} propto (V_{gs}-V_T)^2) (where VT is the threshold voltage at which drain current begins) in the space-charge-limited region above threshold. A quadratic behavior is not observed in modern devices, for example, at the 65 nm technology node. For low noise at narrow bandwidth the higher input resistance of the FET is advantageous. FETs are divided into two families: junction FET (JFET) and insulated gate FET (IGFET). The IGFET is more commonly known as metal-oxide-semiconductor FET (MOSFET), from their original construction as a layer of metal (the gate), a layer of oxide (the insulation), and a layer of semiconductor. Unlike IGFETs, the JFET gate forms a PN diode with the channel which lies between the source and drain. Functionally, this makes the N-channel JFET the solid state equivalent of the vacuum tube triode which, similarly, forms a diode between its grid and cathode. Also, both devices operate in the depletion mode, they both have a high input impedance, and they both conduct current under the control of an input voltage. Metal-semiconductor FETs (MESFETs) are JFETs in which the reverse biased PN junction is replaced by a metal-semiconductor Schottky-junction. These, and the HEMTs (high electron mobility transistors, or HFETs), in which a two-dimensional electron gas with very high carrier mobility is used for charge transport, are especially suitable for use at very high frequencies (microwave frequencies; several GHz). Unlike bipolar transistors, FETs do not inherently amplify a photocurrent. Nevertheless, there are ways to use them, especially JFETs, as light-sensitive devices, by exploiting the photocurrents in channel-gate or channel-body junctions. FETs are further divided into depletion-mode and enhancement-mode types, depending on whether the channel is turned on or off with zero gate-to-source voltage. For enhancement mode, the channel is off at zero bias, and a gate potential can enhance the conduction. For depletion mode, the channel is on at zero bias, and a gate potential (of the opposite polarity) can deplete the channel, reducing conduction. For either mode, a more positive gate voltage corresponds to a higher current for N-channel devices and a lower current for P-channel devices. Nearly all JFETs are depletion-mode as the diode junctions would forward bias and conduct if they were enhancement mode devices; most IGFETs are enhancement-mode types.[3] OTHER TRANSISTORS TYPE I. Point-contact transistor, first type of transistor ever constructed II. Bipolar junction transistor (BJT) a. Heterojunction bipolar transistor up to 100s GHz, common in modern ultrafast and RF circuits b. Grown-junction transistor, first type of BJT c. Alloy-junction transistor, improvement of grown-junction transistor i. Micro-alloy transistor (MAT), faster than alloy-junction transistor ii. Micro-alloy diffused transistor (MADT), faster than MAT, type of a diffused-base transistor iii. Post-alloy diffused transistor (PADT), faster than MAT, type of a diffused-base transistor iv. Schottky transistor v. Surface barrier transistor d. Drift-field transistor e. Avalanche transistor f. Darlington transistors are two BJTs connected together to provide a high current gain equal to the product of the current gains of the two transistors. g. Insulated gate bipolar transistors (IGBTs) use a medium power IGFET, similarly connected to a power BJT, to give a high input impedance. Power diodes are often connected between certain terminals depending on specific use. IGBTs are particularly suitable for heavy-duty industrial applications. The Asea Brown Boveri (ABB) 5SNA2400E170100 illustrates just how far power semiconductor technology has advanced. Intended for three-phase power supplies, this device houses three NPN IGBTs in a case measuring 38 by 140 by 190mm and weighing 1.5kg. Each IGBT is rated at 1,700 volts and can handle 2,400 amperes. h. Photo transistor React to light III. Field-effect transistor a. JFET, where the gate is insulated by a reverse-biased PN junction b. MESFET, similar to JFET with a Schottky junction instead of PN one i. High Electron Mobility Transistor (HEMT, HFET, MODFET) c. MOSFET, where the gate is insulated by a thin layer of insulator d. Inverted-T field effect transistor (ITFET) e. FinFET The source/drain region forms fins on the silicon surface. f. FREDFET Fast-Reverse Epitaxial Diode Field-Effect Transistor g. Thin film transistor Used in LCD display. h. OFET Organic Field-Effect Transistor, in which the semiconductor is an organic compound i. Ballistic transistor j. Floating-gate transistor Used for non-volatile storage. k. FETs used to sense environment i. Ion sensitive field effect transistor To measure ion concentrations in solution. ii. EOSFET Electrolyte-Oxide-Semiconductor Field Effect Transistor (Neurochip) iii. DNAFET Deoxyribonucleic acid field-effect transistor IV. Spacistor V. Diffusion transistor, formed by diffusing dopants into semiconductor substrate; can be both BJT and FET VI. Unijunction transistors can be used as simple pulse generators. They comprise a main body of either P-type or N-type semiconductor with ohmic contacts at each end (terminals Base1 and Base2). A junction with the opposite semiconductor type is formed at a point along the length of the body for the third terminal (Emitter). VII. Single-electron transistors (SET) consist of a gate island between two tunnelling junctions. The tunnelling current is controlled by a voltage applied to the gate through a capacitor. VIII. Spin transistor Magnetically-sensitive IX. Nanofluidic transistor Control the movement of ions through sub-microscopic, water-filled channels. Nanofluidic transistor, the basis of future chemical processors X. Multigate devices a. Tetrode transistor b. Pentode transistor c. Multigate device d. Trigate transistors (Prototype by Intel) e. Dual gate FETs have a single channel with two gates in cascode; a configuration that is optimized for high frequency amplifiers, mixers, and oscillators f. Semiconductor material XI. The first BJTs were made from germanium (Ge). Silicon (Si) types currently predominate but certain advanced microwave and high performance versions now employ the compound semiconductor material gallium arsenide (GaAs) and the semiconductor alloy silicon germanium (SiGe). Single element semiconductor material (Ge and Si) is described as elemental. Rough parameters for the most common semiconductor materials used to make transistors are given in the table below; it must be noted that these parameters will vary with increase in temperature, electric field, impurity level, strain and various other factors: Semiconductor material characteristics Semiconductormaterial Junction forwardvoltageV @ 25  °C Electron mobilitym ²/(V ·s) @ 25  °C Hole mobilitym ²/(V ·s) @ 25  °C Max. junction temp. °C Ge 0.27 0.39 0.19 70 to 100 Si 0.71 0.14 0.05 150 to 200 GaAs 1.03 0.85 0.05 150 to 200 Al-Si junction 0.3 — — 150 to 200 The junction forward voltage is the voltage applied to the emitter-base junction of a BJT in order to make the base conduct a specified current. The current increases exponentially as the junction forward voltage is increased. The values given in the table are typical for a current of 1 mA (the same values apply to semiconductor diodes). The lower the junction forward voltage the better, as this means that less power is required to drive the transistor. The junction forward voltage for a given current decreases with increase in temperature. For a typical silicon junction the change is approximately −2.1 mV/ °C. The density of mobile carriers in the channel of a MOSFET is a function of the electric field forming the channel and of various other phenomena such as the impurity level in the channel. Some impurities, called dopants, are introduced deliberately in making a MOSFET, to control the MOSFET electrical behavior. The electron mobility and hole mobility columns show the average speed that electrons and holes diffuse through the semiconductor material with an electric field of 1 volt per meter applied across the material. In general, the higher the electron mobility the faster the transistor. The table indicates that Ge is a better material than Si in this respect. However, Ge has four major shortcomings compared to silicon and gallium arsenide: I. its maximum temperature is limited II. it has relatively high leakage current III. it cannot withstand high voltages IV. it is less suitable for fabricating integrated circuits Because the electron mobility is higher than the hole mobility for all semiconductor materials, a given bipolar NPN transistor tends to be faster than an equivalent PNP transistor type. GaAs has the highest electron mobility of the three semiconductors. It is for this reason that GaAs is used in high frequency applications. A relatively recent FET development, the high electron mobility transistor (HEMT), has a heterostructure (junction between different semiconductor materials) of aluminium gallium arsenide (AlGaAs)-gallium arsenide (GaAs) which has double the electron mobility of a GaAs-metal barrier junction. Because of their high speed and low noise, HEMTs are used in satellite receivers working at frequencies around 12GHz. Max. junction temperature values represent a cross section taken from various manufacturers data sheets. This temperature should not be exceeded or the transistor may be damaged. Al-Si junction refers to the high-speed (aluminum-silicon) semiconductor-metal barrier diode, commonly known as a Schottky diode. This is included in the table because some silicon power IGFETs have a parasitic reverse Schottky diode formed between the source and drain as part of the fabrication process. This diode can be a nuisance, but sometimes it is used in the circuit.[4] Packaging Through-hole transistors (tape measure marked in centimetres) Transistors come in many different packages (chip carriers) (see images). The two main categories are through-hole (or leaded), and surface-mount, also known as surface mount device (SMD). The ball grid array (BGA) is the latest surface mount package (currently only for large transistor arrays). It has solder balls on the underside in place of leads. Because they are smaller and have shorter interconnections, SMDs have better high frequency characteristics but lower power rating. Transistor packages are made of glass, metal, ceramic or plastic. The package often dictates the power rating and frequency characteristics. Power transistors have large packages that can be clamped to heat sinks for enhanced cooling. Additionally, most power transistors have the collector or drain physically connected to the metal can/metal plate. At the other extreme, some surface-mount microwave transistors are as small as grains of sand. Often a given transistor type is available in different packages. Transistor packages are mainly standardized, but the assignment of a transistors functions to the terminals is not: different transistor types can assign different functions to the packages terminals. Even for the same transistor type the terminal assignment can vary (normally indicated by a suffix letter to the part number- i.e. BC212L and BC212K)[5]. CONCLUSION A unified noise model which incorporates both the number fluctuation and the correlated surface mobility fluctuation mechanism is discussed. The latter is attributed to the Coulombic scattering effect of the fluctuating oxide charge. The model has a functional form resembling that of the number fluctuation theory, but at certain bias conditions it may reduce to a form compatible with Hooges empirical expression. The model can unify the noise data reported in the literature, without making any ad hoc assumption on the noise generation mechanism. Specifically, the model can predict the right magnitude and bias dependence of the empirical Hooge parameter. Simulated noise characteristics obtained with a circuit-simulation-oriented fnoise model based on the new formulation were compared with experimental noise data. Excellent agreement between the calculations and measurement was observed in both the linear and saturation regions for MOS transistors fabricated by different technologies. T he work shows that the flicker noise in MOS transistors can be completely explained by the trap charge fluctuation mechanism, which produces mobile carrier number fluctuation and correlated surface mobility fluctuationIn electronics, a transistor is a semiconductor device commonly used to amplify or switch electronic signals. A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistors terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much larger than the controlling (input) power, the transistor provides amplification of a signal. The transistor is the fundamental building block of modern electronic devices, and is used in radio, telephone, computer and other electronic systems. Some transistors are packaged individually but most are found in integrated circuits. REFERENCES- [1]www.ciphersbyritter.com/NOISE/NOISRC.HTM [2]www.nikhef.nl/~jds/vlsi/noise/transistor [3]www.colorado.edu/physics/phys3330/phys3330_fa05/manual/Exp [4]www.imagesensors.org/Past%20Workshops/2003%20Workshop/2003%20Papers/27%20Findlater%20et%20al [5]www.ansoft.com/news/articles/HF0605