Electric Hazards and the Human Body

Electric Hazards and the Human Body tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập lớn về tất cả các l...

The Human Body February 28th, 2009 Goto comments Leave a comment The Body - A 1. face 6. arm 11. back 16. hip 2. mouth 7. upper arm 12. chest 17. leg 3. chin 8. elbow 13. waist 18. thigh 4. neck 9. forearm 14. abdomen 19. knee 5. shoulder 10. armpit 15. buttocks 20. calf The Hand - B 21.wrist 24. thumb 27. ring finger 22.knuckle 25. (index) finger 28. little finger 23.fingernail 26. middle finger 29. palm The Head - C 30. hair 35. cheek 40. mustache 31. part 36. nose 41. tongue 32. forehead 37. nostril 42. tooth 33. sideburn 38. jaw 43. lip 34. ear 39. beard The Eye - D 44. eyebrow 45. eyelid 46. eyelashes 47. iris 48. pupil The Foot - E 49. ankle 53. big toe 50. heel 54. toe 51. instep 55. little toe 52. ball 56. toenail The Internal Organs - F 57. brain 65. liver 58. spinal cord 66. stomach 59. throat 67. intestines 60. windpipe 68. vein 61. esophagus 69. artery 62. muscle 70. kidney 63. lung 71. pancreas 64. heart 72. bladder Electric Hazards and the Human Body Electric Hazards and the Human Body Bởi: OpenStaxCollege There are two known hazards of electricity—thermal and shock A thermal hazard is one where excessive electric power causes undesired thermal effects, such as starting a fire in the wall of a house A shock hazard occurs when electric current passes through a person Shocks range in severity from painful, but otherwise harmless, to heart-stopping lethality This section considers these hazards and the various factors affecting them in a quantitative manner Electrical Safety: Systems and Devices will consider systems and devices for preventing electrical hazards Thermal Hazards Electric power causes undesired heating effects whenever electric energy is converted to thermal energy at a rate faster than it can be safely dissipated A classic example of this is the short circuit, a low-resistance path between terminals of a voltage source An example of a short circuit is shown in [link] Insulation on wires leading to an appliance has worn through, allowing the two wires to come into contact Such an undesired contact with a high voltage is called a short Since the resistance of the short, r, is very small, the power dissipated in the short, P = V2 / r, is very large For example, if V is 120 V and r is 0.100 Ω , then the power is 144 kW, much greater than that used by a typical household appliance Thermal energy delivered at this rate will very quickly raise the temperature of surrounding materials, melting or perhaps igniting them 1/10 Electric Hazards and the Human Body A short circuit is an undesired low-resistance path across a voltage source (a) Worn insulation on the wires of a toaster allow them to come into contact with a low resistance r Since P = V2 / r , thermal power is created so rapidly that the cord melts or burns (b) A schematic of the short circuit One particularly insidious aspect of a short circuit is that its resistance may actually be decreased due to the increase in temperature This can happen if the short creates ionization These charged atoms and molecules are free to move and, thus, lower the resistance r Since P = V2 / r, the power dissipated in the short rises, possibly causing more ionization, more power, and so on High voltages, such as the 480-V AC used in some industrial applications, lend themselves to this hazard, because higher voltages create higher initial power production in a short Another serious, but less dramatic, thermal hazard occurs when wires supplying power to a user are overloaded with too great a current As discussed in the previous section, the power dissipated in the supply wires is P = I2Rw, where Rw is the resistance of the wires and I the current flowing through them If either I or Rw is too large, the wires overheat For example, a worn appliance cord (with some of its braided wires broken) may have Rw = 2.00 Ω rather than the 0.100 Ω it should be If 10.0 A of current passes through the cord, then P = I2Rw = 200 W is dissipated in the cord—much more than is safe Similarly, if a wire with a 100 - Ω resistance is meant to carry a few amps, but is instead carrying 100 A, it will severely overheat The power dissipated in the wire will in that case be P = 1000 W Fuses and circuit breakers are used to limit excessive currents (See [link] and [link].) Each device opens the circuit automatically when a sustained current exceeds safe limits 2/10 Electric Hazards and the Human Body (a) A fuse has a metal strip with a low melting point that, when overheated by an excessive current, permanently breaks the connection of a circuit to a voltage source (b) A circuit breaker is an automatic but restorable electric switch The one shown here has a bimetallic strip that bends to the right and into the notch if overheated The spring then forces the metal strip downward, breaking the electrical connection at the points Schematic of a circuit with a fuse or circuit breaker in it Fuses and circuit breakers act like automatic switches that open when sustained current exceeds desired limits Fuses and circuit breakers for typical household voltages and currents are relatively simple to produce, but those for large voltages and currents experience special problems For example, when a circuit breaker tries to interrupt the flow of high-voltage electricity, a spark can jump across its points that ionizes the air in the gap and allows the current to continue flowing Large circuit breakers found in power-distribution systems employ insulating gas and even use jets of gas to blow out such sparks Here AC is safer than DC, since AC current goes through zero 120 times per second, giving a quick opportunity to extinguish these arcs 3/10 Electric Hazards and the Human Body Shock Hazards Electrical currents through people produce tremendously varied effects An electrical current can be used to block back pain The possibility of using electrical current to stimulate muscle action in paralyzed limbs, perhaps ... H ere is a pop quiz:Who was Gluteus Maximus? Even though it sounds like the name of some ancient Roman general, gluteus maximus is actually the name of a muscle. Its claim to fame is that it’s the largest muscle in the human body. Can you guess where one can find it? Hint: you sit on it. An incredible machine, the human body is a source of many fascinating facts, discoveries, and tidbits. Here is one more: Who has a greater number of bones, babies or adults? Babies have more than 300 bones, while adults have just 206. As we grow, many bones in our body fuse together. Here are a few terms that are synonyms for better-known words relating to the human body. nares (NAR-eez), singular naris noun The nostrils or nasal passages. From Latin nares, plural of naris (nostril). This word shares the same root (nas-) with nose, nuzzle, nostril, nasal, and pince-nez. ● “There’s a fine frost around their eyes and nares.” —Alaska 90 CHAPTER 22 Words Related to the Human Body cmp03.qxd 7/21/05 12:16 PM Page 90 oxter (OK-stuhr) noun The armpit. From Old English oxta. The Latin form is axilla.Both allude to the idea of the axis around which the arm rotates. ● “I got lumbered in the three-legged race with a guy so much shorter than me that he barely came up to my armpit. It would have been easier for me to have tucked him under my oxter and just carried him to the finish.” —Guardian (London) pollex (POL-eks), plural pollices noun The thumb. From Latin pollex. Hallux is the equivalent term for the big toe. ● “He caught his thumb between his gun and a sharp rock. It was a nasty cut spurting blood. I said,‘Ben, that’s it. We’ve got to get you to a doctor.’‘Heck no, let’s get a turkey first,’ answered Ben, quickly wrapping his dripping pollex with a handkerchief.” —Albany (N.Y.) Times Union W ORDS RELATED TO THE HUMAN BODY 91 Facts do not cease to exist because they are ignored. — A LDOUS H UXLEY , author (1894–1963) Oxtercog When settlers came here in the 1600s, they brought with them many words from seventeenth-century England and Scotland, which comprise a dialect now known as “Ulster- Scots.”While in England words such as oxter have fallen out of everyday use, they are still heard frequently here. A related word is the verb oxtercog, which means to drag somebody along by their armpits—people often need to be oxtercogged to a taxi after they have had one drink too many. —Wesley Johnston, Newtownabbey, Northern Ireland cmp03.qxd 7/21/05 12:16 PM Page 91 nevus (NEE-vuhs) noun A congenital blemish on the skin, such as a mole or birth- mark. From Latin naevus (mole). ● “Stephany had a hairy nevus, a big mole on her cheek right underneath the eyelid and across the nose.” —San Diego Business Journal glossal (GLOS-uhl) adjective Of or pertaining to the tongue. From Greek glossa (tongue). ● “Anthony Herrel, a researcher at the University of Antwerp, wondered how chameleons capture creatures nearly one-sixth their size—the equivalent of a human bagging a large turkey— using only their glossal appendages. Granted, the lizards’ sling- shot tongues are comparatively longer than humans’ tongues, but that still doesn’t account for chameleons’ prodigious snar- ing abilities.” —National Wildlife 92 ANOTHER WORD A DAY A man cannot be comfortable without his own approval. — M ARK T WAIN , author and humorist (1835–1910) cmp03.qxd 7/21/05 12:16 PM Page 92 W hen I came to NguyÔn §×nh Lu. 40A2 - English Acknowledgements The thesis could not have been completed without the devoted help of many people during the time of my doing it. Firstly, I would like to express my deep thank to my supervisor Lª §×nh Th¶o (M.A) who helped me devotedly and thoughtfully to finish this thesis. Secondly, I am grateful to my teachers from the Department of Foreign Languages, especially the former Dean NguyÔn Xu©n B×nh (M.A) who gave us chance to do the work. Thirdly, I am also indebted to my dear teacher Chrisstaples and my dear friends who helped me a lot. Student: NguyÔn §×nh Lu Class: 40A2 - English Index Graduation thesis - A contrastive analysis on English and Vietnamese proverbs referring to parts of the human body 1 NguyÔn §×nh Lu. 40A2 - English Pages Acknowledgments 1 Index 2 Part A. Introduction 1. Rationale for choosing the subject . 4 2. Aims of the study . .…… . 5 3. Objects of the study 5 4. Methods of the study . 6 5. Scope of the study 6 6. Design of the study 6 Part B. Content Chapter 1. Background 7 1. Where do proverbs come from? . 7 1.1.Where do English proverbs come from? 7 1.2. Where do Vietnamese proverbs come from? 8 2. The position of proverbs in lexicology 10 2.1. Word structure and formation 10 2.2. Semantics Acknowledgements The thesis could not have been completed without the help of my teachers and friends during the time of my doing it . Firstly, I would like to express my deep thank to my supervisor - the Dean of the Department of Foreign Languages - Master of Arts Ng« §×nh Ph- ¬ng for his great support and constant and helpful advices on my study. Secondly, I am grateful to Master of Arts TrÇn Ngäc Tëng and Mr chrisstaples for their useful advices from the early stages of the study. Thirdly, I would also like to thank my teachers in the Department of Foreign Languages and friends who helped me a lot throughout my study. Vinh, May 2004 1 Table of contents Page Acknowledgements 1 Table of contents 2 Part A. Introduction 4 1. Reasons for choosing the subject 4 2. Aims of the study 5 3. Objectives of the study 5 4. Methods of the study 6 5. Design of the study 6 Part B. contents 7 Chapter 1. Theoretical preLiminaries 7 1.1. Contrastive analysis on languages 7 1.2. The rule of semantic transference 8 1.3. Names of part of the human body with the transference of meaning and cultural symbolism. 12 Chapter 2. The contrastive analysis of class of words denoting parts of the human body in English and Vietnamese on semantic transference. 14 2.1. The origin of names referring to parts of the human body. 14 2.2. The features of semantic transference 16 2.2.1 Quantitative features 16 2.2.2 Qualitative features 28 2 Chapter 3. Suggested exercises 35 3.1 The basic of exercises 35 3.2 The user of exercises 36 3.3 Suggested exercises 36 Part C. Conclusion 42 References 43 Appendix 44 3 Part A. Introduction 1. Reasons for choosing the subject Polysemantic words are a general and specific phenomenon of many languages in the world. In both daily spoken language and literary language in English and Vietnamese, we often meet the use of polysemy. For example: "Use your head ! "; " Report to the Head immediately "; " The arm of my jacket", " The arm of a chair ", etc. We are really interested in studying them, specially the meanings of words denoting parts of the human body in English and Vietnamese. Choosing two languages, English and Vietnamese to make a contrastive analysis has scientific base on linguistics and culture. England and Vietnam have their own culture, human race, geography and history. We can also see that, the class of words denoting parts of the human body is very familiar to us and has rich development of meaning in each language. These words are realized early by the native speakers. They belong to the original stock of the lexical system in each language. Studying the transference of meaning through this class of words attracts us much. Furthermore, because of the importance and necessity of substratum knowledge in teaching and learning English and Vietnamese, we would like to examine and find out some relationships between two languages. When [...]... another completely different tool) In the following, the Web3D H-anim standards, the MPEG-4 face and body animation, as well as MPEG-4 AFX extensions for humanoid animation, are briefly introduced The Web3D H-Anim Standards The Web3D H-anim working group (H-anim) was formed so that developers could agree on a standard naming convention for human body parts and joints The human form has been studied for. .. is introduced 3D Human Body Modeling Modeling a human body first implies the adaptation of an articulated 3D structure, in order to represent the human body biomechanical features Secondly, it implies the definition of a mathematical model used to govern the movements of that articulated structure Several 3D articulated representations and mathematical formalisms have been proposed in the literature... higher complexity than the classical rigid object modeling It takes advantage of most of the techniques proposed within the rigid object modeling community, together with a prior-knowledge of human body movements based on a kinematics and dynamics study of the human body structure The huge amount of articles published during the last years involving 3D human body modeling demonstrates the increasing interest... techniques, since they are commonly used for 3D reconstruction Model-based techniques rely on a mathematical representation of human body structure and motion dynamics The type of the model used depends upon the requisite accuracy and the permissible complexity of pose reconstruction Model-based approaches usually exploit the kinematics and dynamics of the human body by imposing constraints on the model’s... order to detect the commencement and termination of actions, the human skeleton is extracted and the angles subtended by the torso, the upper leg and the lower leg, are estimated Each action is then recognized based on the characteristic path that these angles traverse This technique, though, relies on lateral views of the human body Park & Aggarwal (2000) propose a method for separating and classifying... information about the 3D geometry, color and texture of the body part associated with that joint Joint nodes may also contain hints for inversekinematics systems that wish to control the H-anim figure, such as the upper and lower joint limits, the orientation of ... extend the legs and torso (b) The victim can’t let go of the wire that is stimulating all the muscles in the hand Those that close the fingers are stronger than those that open them 4/10 Electric Hazards. .. Khimich Alex, Wikimedia Commons) 7/10 Electric Hazards and the Human Body Section Summary • The two types of electric hazards are thermal (excessive power) and shock (current through a person)... thousand ohms) when the skin is wet Explain these observations and their implications regarding skin and internal resistance of the human body What are the two major hazards of electricity? Why