Saturday, May 23, 2020

Zoology Essay - 1264 Words

Zoology The study of zoology can be viewed as a series of efforts to analyse and classify animals. Attempts at classification as early as 400 BC are known from documents in the Hippocratic Collection. Aristotle, however, was the first to devise a system of classifying animals that recognized a basic unity of plan among diverse organisms; he arranged groups of animals according to mode of reproduction and habitat. Observing the development of such animals as the dogfish, chick, and octopus, he noted that general structures appear before specialized ones, and he also distinguished between asexual and sexual reproduction. His Historia Animalium contains accurate descriptions of extant animals of†¦show more content†¦Perhaps the most important naturalist of the era was the German scholar St Albertus Magnus, who denied many of the superstitions associated with biology and reintroduced the work of Aristotle. The anatomical studies of Leonardo da Vinci were far in advance of the age. His d issections and comparisons of the structure of humans and other animals led him to important conclusions. He noted, for example, that the arrangement of joints and bones in the leg are similar in both horses and humans, thus grasping the concept of homology (the similarity of corresponding parts in different kinds of animals, suggesting a common grouping). The value of his work in anatomy was not recognized in his time. Instead, the Belgian doctor Andreas Vesalius is considered the father of anatomy; he circulated his writings and established the principles of comparative anatomy. Classification dominated zoology throughout most of the 17th and 18th centuries. The Swedish botanist Carolus Linnaeus developed a system of nomenclature and classification that is still used today—the binomial system of genus and species—and established taxonomy as a discipline. He followed the work of the English naturalist John Ray in relying upon the form of teeth and toes to differentiate mammals and upon beak shape to classify birds. Another leading systematist of this era was theShow MoreRelatedPhysical And Mental Requirements Of Zoology1155 Words   |  5 Pages One of the most interesting jobs of today is a Zoologist. Not only is this job very easy to acquirer it can also benefit someone. The main factors to look up in zoology are the job requirements like physical and mental requirements, the education you acquire, job advancement, the salary, the responsibilities it comes with, and the travel opportunities. This job can help a person by giving them kn owledge and adventure in their life. It can provide him or her with essentials they will need inRead MoreTaking a Look at Ornithology643 Words   |  3 PagesOrnithology    Ornithology is a branch of zoology that deals with the study of birds, and ornithologist studies the variety of things on birds such as bird anatomy, behavior, biology, evolution, ecology and physiology. For an ornithologist, there is no standard or even an average starting salary because few people are hired strictly as ornithologist. Instead, they are hired as teachers, professors, wildlife biologists, environmental scientists, environmental educators, ecologists, tour leaders, andRead MoreAs Times Change : Traditional Vs. Experiential1457 Words   |  6 Pagesand the elite. Only few people of the population could afford to expand beyond homeland territory to explore wild life and exotic cultures. Exotic animals were seen as status symbols. 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Zoology Syllabus Restructured for Credit Based and Grading System To be implemented from the Academic year 2010-2011 SEMESTER I Course Code UNIT I USZO101 II III I USZO102 II III USZO P1 TOPICS Diversity of Animal Kingdom I Life processes I Ecology Molecular basis of lifeRead MoreJournal Of Entomology And Zoology Studies2099 Words   |  9 PagesJournal of Entomology and Zoology Studies 2015; 3( 5): 01-06 P-ISSN: 2349-6800 E-ISSN: 2320-7078 JEZS 2015; 3(5): 01-06  © 2015 JEZS Received: 05-07-2015 Accepted: 06-08-2015 A. S. Abd El-Wahab Department of Economic Entomology and Pesticides, Faculty of Agriculture, Cairo University, Giza, Egypt Correspondence: A. S. Abd El-Wahab Department of Economic Entomology and Pesticides, Faculty of Agriculture, Cairo University, Giza, Egypt Identification of a new species, Marigold thrips NeohydatothripsRead MoreLineage-Based Perspective743 Words   |  3 Pagesfor all biology majors to have a working knowledge of the tree of life. The two perspectives for teaching zoology are the Linnean taxonomical and the Phylogenetic clade-based perspective. The Linnean taxonomical perspective is a rank-based hierarchy while the phylogenetic clade-based perspective groups species by focusing a common ancestor and its descendants. In regards to teaching zoology there is more value in using the phylogenetic clade-based perspective rather than the Linnean perspective becauseRead MoreThe University Of Wisconsin Madison1597 Words   |  7 Pageschoose if I attend this college would be Zoology. I would choose this major because Zoology is the study of all animals, and would help me further understand the world of animals on a scientific level. It would also help me get into Vet School after undergraduate school. Zoology has one of the best placement records for premedical students. As i said in the last paragraph Zoology is the study of all animals. 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Wednesday, May 6, 2020

Industrial Instrumentation On Load Cells Engineering Essay Free Essays

string(89) " overseas telegram opposition and therefore long signal overseas telegrams are non jobs\." Load cells are detectors which are used to mensurate the degree or force per unit area by change overing the force ( torsion or mass ) into electrical signals and so these signals are displayed by the show unit to demo the degree or force per unit area. Load cells are besides known as burden transducers. In dictionary, a burden cell is known as â€Å" weight mensurating device necessary for electronic signal that displays weight in the signifier of figures. We will write a custom essay sample on Industrial Instrumentation On Load Cells Engineering Essay or any similar topic only for you Order Now † Load cells can be classified harmonizing to their operations: Load cells that utilize liquid force per unit area or air force per unit area. Load cells that utilize snap. Load cells that utilize a magnetostriction or piezoelectric consequence. The strain gage burden cell is the largely used among the all sorts of burden cells. Therefore, when we say â€Å" burden cell, † we are largely mentioning to strive gauge burden cells. Although there are many other measurement devices, such as piezoelectric detectors, magnetostrictive detectors, electrical capacity detector and other detectors. 1.2-Types of Load cells Strain gage burden cells Tension burden cells Pneumatic burden cells Hydraulic burden cells Shear Load Cells Compression Load Cells Bending Load Cells Ringing Torsion Load Cells Pancake Load Cells Single Point Load Cells 1.3-Strain Gauge Load Cells This is a type of burden cell which is usage to mensurate the degree of any storage vas. 1.3.1-Working rule When force per unit area is applied on a music director its length alterations due to which opposition of the music director alterations and relation to the alteration in opposition show unit displays the alteration in degree. 1.3.2-Construction and working A strain gage is consists of a long length music director which is arranged in zig-zag manner on the flexible membrane which is exposed to the applied force per unit area country. This music director is connected in a wheat rock span as a resistance and when force per unit area or weight is applied on the membrane which is connected to the music director it gets stretched and due to stretching the length of the music director alterations and due to alter in length the opposition of the music director additions. These are normally four or a multiple of four, are connected into a wheat rock span constellation in order to change over the really little alteration in the opposition into the suited electrical signal. As these gages are combination of mechanical and electrical constituents so the mechanical parts are located at the site but electrical parts are in the control suites due to their environmental and temperature sensitivenesss. And the wires used for the transmittal of the signals besides have their ain opposition so that opposition besides considered during their building. The accommodation and arrangement of the strain gage burden cell in the wheat rock span and its working phenomena is shown in the undermentioned diagrams. Strain gage burden cells are placed at the underside of the vass largely to mensurate the degree of the column or vas. 00204.png Figure Figure 00205.png 1.3.3-Advantages Strain gage burden cells are used in automotive industry to look into the structural public presentations of the stuff used in doors, goons, short pantss etc. Strain gage burden cells can be usage for weighing intents. Strain gage burden cells can besides be usage for stuff testing in procedure industry besides. Strain gage burden cells are besides used in tensile trial machines as a major constituent. Strain gage burden cells truth is 0.07 % of the rated capacity Strain gage burden cells can be used for both enlargement and compaction. Strain gage burden cells are less dearly-won so largely used in the industry. 1.3.4-Disadvantages Strain gage burden cells require uninterrupted electric energy for the production and show of signals. Strain gage burden cells besides requires an elaboration circuit for the coevals of end product show because the signals produced by the gage itself are of really much low electromotive force about in milli Vs. Strain gage burden cells can non be used for the force per unit area measuring of extremely reactive or caustic stuffs because they can damage the gage. Strain gage burden cells can non be used for the measuring of really high force per unit area if the stop usage is of plastic. 1.4-Tension Load Cells This is another type of burden cell which is besides usage to step to the degree. 1.4.1-Working Principle It consists of a vibrating wire transducer, fixed in a thick-vessel metallic cylinder, designed to supply a extremely stable and sensitive agencies of supervising tensile tonss in weighing systems, like procedure weighing systems and batch systems. As the applied burden additions on the burden cells the force on the internal vibrating wire besides increases by altering its tenseness, and therefore the resonating frequence of the vibrating wire. The frequence is measured and relative to the applied weight. 1.4.2-Construction and working The chief portion of this burden cell is strain gauged stop which is for good secured in the transducer shell. The transducer is fitted with a metallic oculus leting in line connexion to the deliberation system, and a metallic hook, attached to the sensitive stop, provides a agency by which weight is applied in a suspended manner. The burden cell is vented to the ambiance to extinguish barometric effects for the upper limit or optimal truth. The signal overseas telegram which is attached to the burden cell is connected with the control room where these signals can be monitored. Figure There are besides some Thermistors placed inside its shell which are used to mensurate the temperature of the working fluid or vas. Degree centigrade: UsersAlY RaZaAppDataLocalMicrosoftWindowsTemporary Internet FilesContent.WordUntitled.png 1.4.3-Advantages The chief advantage of the tenseness burden cell is that it is extremely sensitive and stable. As it is a vibrating component wire detector and its end product is frequency so it is non affected by the alteration in the overseas telegram opposition and therefore long signal overseas telegrams are non jobs. You read "Industrial Instrumentation On Load Cells Engineering Essay" in category "Essay examples" The frequence of the vibrating wire is measured by either the portable read-out box or informations lumberman. So it can give more accurate readings. The end product signal scopes in the electromotive force from 0 to 5 Vs so there is no elaboration unit required and therefore the cost lessenings. The rated capacity of the tortuosity burden cell is from 10 kilograms to 15 kilograms. The truth of the tortuosity burden cells is A ±0.1 % The temperature ranges for the working or operation of the tortuosity burden cells is -20A °C to +80A °C. Such types of transducers have about zero impetus and have besides really low consequence of temperature on its truth. 1.4.4-Disadvantages This type of burden cells can non be used for high temperature fluids to happen degree or weight of fluid incorporating column. This type of burden cells can non besides be used for high capacities or for big armored combat vehicles column or weight measurings. This type of burden cell is extremely affected by the high temperatures due to its sensitive nature of the detection wire. 1.5-Pneumatic Load Cells This is another type of burden cells which are usage to mensurate the weight in the industry and these are used for low capacity. 1.5.1-Working Principle This type of burden cells works on â€Å" the force-balance rule. † 1.5.2-The Force-Balance Principle The inertial force produced by a seismal land gesture shifts the mass from its original equilibrium place, and the alteration in place or speed of the mass is so interpreted into an electric signal. This rule is for low scope burden cells. For long scope burden cells the inertial force is balanced with an electrically generated force so that the mass moves every bit low as possible. 1.5.3-Working of pneumatic burden cell This sort of burden cells consist of a detection component which is exposed to the site or the vas of which force per unit area or lying unstable weight is to be measured. And in this sort of burden cell the force reassigning medium is air as comparison to the any other fluid in instance of hydraulic burden cell. When force is applied by the lying fluid on the feeling portion of the burden cell it transfers this force to the inside air and so this force is applied on the potentiometer which is placed in the wheat rock span. As the force is applied on the feeling portion of the burden cell the opposition of the variable opposition potentiometer alterations due to this force and therefore the possible equilibrium between the oppositions is disturbed and this shows the magnitude of the applied force on the feeling component by exposing it on the show unit. Figure pneumatic.gif Another technique which is largely used in such sort of burden cells is the use of the piezoelectric crystals. In this sort the detection component transportations applied force to the interior fluid ( air ) and it imparts this force on the crystal. And due to the application of the applied force on the crystal by agencies of air its construction gets disturbed and due to disturbance in the construction the possible across the crystal alterations and this alteration in the possible across the crystal is detected by the voltmeter and so this electromotive force is converted into weight of force units and displayed on the exposing unit. Most of the clip wheat rock span is used for this sort of burden cell and there is merely variable resistance largely used while other resistances in the wheat rock span are of fixed opposition. 1.5.4-Advantages They are largely used on smaller tons when safety and protection are of premier concern. They are better in truth as comparison to the hydraulic burden cells because there is no alteration in the denseness and truth of the fluid being used for the transportation of applied force. They besides preferred on the hydraulic burden cells because there is no usage of liquid in these sorts of burden cells. These types of burden cells are inherently explosion cogent evidence and insensitive to temperature fluctuations. As they contain no fluids so there is no job of taint of the procedure if the stop gets ruptured. Pneumatic burden cells are besides used to mensurate little weights that depend upon cleanliness and safety. 1.5.5-Disadvantages The chief disadvantage of these types of burden cells is that they can non be used for high measure measuring. Although they are really resistive to the temperature effects but their truth even acquire disturbed at really high temperature. 1.6-Hydraulic Load Cells This is another type of burden cells which are used to mensurate the magnitude of the applied force and their transition to the electric signals and its digital show. 1.6.1-Working Principle This type of burden cells besides work on â€Å" the force-balance rule. † The difference between the pneumatic burden cell and hydraulic burden cell is merely the transferring medium. In instance of pneumatic burden cell the force reassigning medium is air while in hydraulic burden cells the force reassigning medium is largely liquid or incompressible oil which is besides known as break oil. 1.6.2-Construction and working Hydraulic burden cell consists of a fluid which act as a force reassigning medium and a piezoelectric crystal which is usage to change over this applied force into possible difference and so there is an agreement for the transition of this possible difference in footings of weight or force per unit area. There is a stop which is usage to feel the force exerted from the external side and the whole shell in which this complete cell is enclosed. When the force per unit area or weight by the vas or column is applied on the stop of the burden cell it sense that force and so transportations this force to the fluid which is filled in the shell of this burden cell. Then this force is transferred to the piezoelectric crystal by the fluid or oil and this oil transfers this force by the Pascal ‘s jurisprudence. So when the force is transferred by the oil it disturbs the internal construction of the piezoelectric crystal and due to this alteration in the construction of the piezoelectric crystal a possible difference is generated across the piezoelectric crystal. This possible difference is detected by the electric sensor and electric signal is transferred to the show unit to expose the magnitude of the applied force, weight or force per unit area. Figure Hydraulic.gif 1.6.3-Advantages These are largely use to happen the weight of the stuff in the storage armored combat vehicles, bin or hopper. The end product given by these types of burden cells is additive and largely unaffected by the sum of the filling fluid ( oil ) or by its temperature. If the hydraulic burden cells have been decently installed and calibrated so truth is largely within 0.25 % full graduated table or better and this is acceptable for most procedure weighing applications. As these types of burden cells have no electrical constituents therefore it is ideal for usage in risky or caustic countries. For more accurate measuring, the weight of the armored combat vehicle should be obtained by turn uping a burden cell at different points and summing their end products. 1.6.4-Disadvantages One disadvantage of this type of burden cell is that the elastomeric stop limits the maximal force that can be applied on the Piston or stop to about 1,000 psig. Electronic pari-mutuel machine is required in instance of acquiring more accurate reading by summing the readings of the single burden cells. Another disadvantage of hydraulic burden cell is that they are expensive and are complex to utilize. 1.7-Shear Load Cells This is another type of burden cells which is usage to mensurate the weight or the degree of the column incorporating fluid or some stuff. 1.7.1-Working Principle This type of burden cells works on the shear of the web. A web of an elastic stuff is inserted at some degree in the vas or storage armored combat vehicle and a shear emphasis exerted by the unstable column stretches the web harmonizing to the burden of the unstable column. Therefore by mensurating the shear emphasis the degree or weight of the fluid in a column can be measured. 1.7.2-Construction and working This type of burden cells consists of a web and a frame which is movable and the web is fixed with this frame. There are strain gages which are straight connected with this web and step the weight or degree of the column by mensurating the shear emphasis exerted by the liquid nowadays in the column on the web. As the web is inserted in the liquid column, liquid exerts the force on this web as this web is stretchy and elastic so it gets stretched and this stretched province of the web is sensed by the strain gages. This web is inserted in the liquid column perpendicular to the axis of the column. Then strain gages transfers the mensural value of the shear emphasis exerted by the tallness of the liquid column to the electrical transducers which converts it into electrical signals and so transmits it to the show unit to expose the mensural value of the weight in footings of degree or force per unit area as we required. Figure 1.7.3-Advantages Shear burden cells are popular now for all type of mediums and for high capacities. Shear-web is non limited to merely beam constellations. Shear-web detection component is besides being used by high capacity BSP and USP in a more complex manner. Shear burden cell engineering is besides being used in rearward transducers. Shear tonss cells can readily be sealed and can be protected from the environmental effects. 1.7.4-Disadvantages Shear burden cells have comparatively little sensitiveness at the burden point so can non be used for little graduated table measurings. Shear burden cells are expensive as comparison to the strain gages. Shear burden cells are delicate merely because of the web which is really delicate and can be easy damage due to overload fro few minutes even. How to cite Industrial Instrumentation On Load Cells Engineering Essay, Essay examples

Friday, May 1, 2020

Dylan Thomas and September 11th free essay sample

A paper which discusses the relevance of Dylan Thomas poetry to society today, especially after the terrorist attacks of September 11th. By examining several of Dylan Thomas poems, the paper shows how his continuous themes of the unity of life, the continuing process of life and death, and the life-link between generations are all relevant to society today, despite the fact that Thomas has been dead for over 50 years. The paper shows that in the wake of September 11th, his works, though not exactly comforting, do provide an outlet for a nation suddenly forced to deal with the harsh realities of life and death. A final strength of Thomass work is that he asks hard questions without proposing easy answers. He accepts death in the sense that he knows it is a part of life and must be, but he offers no platitudes about its goodness or rightness. Indeed, in one of his most famous poems, he urges, ?Do not go gentle into that good night. We will write a custom essay sample on Dylan Thomas and September 11th or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page / Rage, rage against the dying of the light.? In another poem, Out of the Pit, he questions, ?[W]heres Gods my Shepherd, God is Love? / No loving shepherd in this upside life.? In his avoidance of the quick fix, Thomas respects his own and his readers fear and hatred of death while acknowledging its reality.

Sunday, March 22, 2020

Safety Precautions in Welding Operations Essay Example

Safety Precautions in Welding Operations Essay To prevent injury to personnel, extreme caution should be exercised when using any types of welding equipment. Injury can result from fire, explosions, electric shock, or harmful agents. Both the general and specific safety precautions listed below must be strictly observed by workers who weld or cut metals. b. Do not permit unauthorized persons to use welding or cutting equipment. c. Do not weld in a building with wooden floors, unless the floors are protected from hot metal by means of fire resistant fabric, sand, or other fireproof material. Be sure that hot sparks or hot metal will not fall on the operator or on any welding equipment components. d. Remove all flammable material, such as cotton, oil, gasoline, etc. , from the vicinity of welding. e. Before welding or cutting, warm those in close proximity who are not protected to wear proper clothing or goggles. f. Remove any assembled parts from the component being welded that may become warped or otherwise damaged by the welding process. . Do not leave hot rejected electrode stubs, steel scrap, or tools on the floor or around the welding equipment. Accidents and/or fires may occur. h. Keep a suitable fire extinguisher nearby at all times. Ensure the fire extinguisher is in operable condition. i. Mark all hot metal after welding operations are completed. Soapstone is commonly used for this purpose. 2-2. PERSON AL PROTECTIVE EQUIPMENT a. General. The electric arc is a very powerful source of light, including visible, ultraviolet, and infrared. Protective clothing and equipment must be worn during all welding operations. We will write a custom essay sample on Safety Precautions in Welding Operations specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Safety Precautions in Welding Operations specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Safety Precautions in Welding Operations specifically for you FOR ONLY $16.38 $13.9/page Hire Writer During all oxyacetylene welding and cutting proccesses, operators must use safety goggles to protect the eyes from heat, glare, and flying fragments of hot metals. During all electric welding processes, operators must use safety goggles and a hand shield or helmet equipped with a suitable filter glass to protect against the intense ultraviolet and infrared rays. When others are in the vicinity of the electric welding processes, the area must be screened so the arc cannot be seen either directly or by reflection from glass or metal. b. Helmets and Shields. 1) Welding arcs are intensely brilliant lights. They contain a proportion of ultraviolet light which may cause eye damage. For this reason, the arc should never be viewed with the naked eye within a distance of 50. 0 ft (15. 2 m). The brilliance and exact spectrum, and therefore the danger of the light, depends on the welding process, the metals in the arc, the arc atmosphere, the length of the arc, and the welding current. Operator s, fitters, and those working nearby need protection against arc radiation. The intensity of the light from the arc increases with increasing current and arc voltage. Arc radiation, like all light radiation, decreases with the square of the distance. Those processes that produce smoke surrounding the arc have a less bright arc since the smoke acts as a filter. The spectrum of the welding arc is similar to that of the sun. Exposure of the skin and eyes to the arc is the same as exposure to the sun. (2) Being closest, the welder needs a helmet to protect his eyes and face from harmful light and particles of hot metal. The welding helmetis generally constructed of a pressed fiber insulating material. It has an adjustable headband that makes it usable by persons with different head sizes. To minimize reflection and glare produced by the intense light, the helmet is dull black in color. It fits over the head and can be swung upward when not welding. The chief advantage of the helmet is that it leaves both hands free, making it possible to hold the work and weld at the same time. (3) The hand-held shield provides the same protection as the helmet, but is held in position by the handle. This type of shield is frequently used by an observer or a person who welds for a short period of time. 4) The protective welding helmet has lens holders used to insert the cover glass and the filter glass or plate. Standard size for the filter plate is 2 x 4-1/4 in. (50 x 108 mm). In some helmets lens holders open or flip upwards. Lenses are designed to prevent flash burns and eye damage by absorption of the infrared and ultraviolet rays produced by the arc. The filter glasses or plates come in vario us optical densities to filter out various light intensities, depending on the welding process, type of base metal, and the welding current. The color of the lens, usually green, blue, or brown, is an dded protection against the intensity of white light or glare. Colored lenses make it possible to clearly see the metal and weld. Table 2-1 lists the proper filter shades to be used. A magnifier lens placed behind the filter glass is sometimes used to provide clear vision. A cover plate should be placed outside the filter glass to protect it from weld spatter. The filter glass must be tempered so that is will not break if hit by flying weld spatter. Filter glasses must be marked showing the manufacturer, the shade number, and the letter â€Å"H† indicating it has been treated for impact resistance. NOTE Colored glass must be manufactured in accordance with specifications detailed in the National Safety Code for the Protection of Hands and Eyes of Industrial Workers†, issued by the National Bureau of Standards, Washington DC, and OSHA Standards, Subpart Q, â€Å"Welding, Cutting, and Brazing†, graph 1910. 252, and American National Standards Institute Standard (ANSI) Z87. 1-1968, â€Å"American National Standard Practice for Occupational and Educational Eye and Face Protection†. (5) Gas metal-arc (MIG) welding requires darker filter lenses than shielded metal-arc (stick) welding. The intensity of the ultraviolet radiation emitted during gas metal-arc welding ranges from 5 to 30 times brighter than welding with covered electrodes. (6) Do not weld with cracked or defective shields because penetrating rays from the arc may cause serious burns. Be sure that the colored glass plates are the proper shade for arc welding. Protect the colored glass plate from molten metal spatter by using a cover glass. Replace the cover glass when damaged or spotted by molten metal spatter. (7) Face shields (fig. 2-2) must also be worn where required to protect eyes. Welders must wear safety glasses and chippers and grinders often use face shields in addition to safety glasses. (8) In some welding operations, the use of mask-type respirators is required. Helmets with the bubble front design can be adapted for use with respirators. c. Safety Goggles. During all electric welding processes, operators must wear safety goggles (fig. 2-3) to protect their eyes from weld spatter which occasionally gets inside the helmet. These clear goggles also protect the eyes from slag particles when chipping and hot sparks when grinding. Contact lenses should not be worn when welding or working around welders. Tinted safety glasses with side shields are recommended, especially when welders are chipping or grinding. Those working around welders should also wear tinted safety glasses with side shields. d. Protective Clothing. (1) Personnel exposed to the hazards created by welding, cutting, or brazing operations shall be protected by personal protective equipment in accordance with OSHA standards, Subpart I, Personal Protective Equipment, paragraph 1910. 132. The appropriate protective clothing (fig. -4) required for any welding operation will vary with the size, nature, and location of the work to be performed. Welders should wear work or shop clothes without openings or gaps to prevent arc rays from contacting the skin. Those working close to arc welding should also wear protective clothing. Clothing should always be kept dry, including gloves. (2) Woolen clothing should be worn instead of cotton since wool is not ea sily burned or damaged by weld spatter and helps to protect the welder from changes in temperature. Cotton clothing, if used, should be chemically treated to reduce its combustibility. All other clothing, such as jumpers or overalls, should be reasonably free from oil or grease. (3) Flameproof aprons or jackets made of leather, fire resistant material, or other suitable material should be worn for protection against spatter of molten metal, radiated heat, and sparks. Capes or shoulder covers made of leather or other suitable materials should be worn during overhead welding or cutting operations. Leather skull caps may be worn under helmets to prevent head burns. (4) Sparks may lodge in rolled-up sleeves, pockets of clothing, or cuffs of overalls and trousers. Therefore, sleeves and collars should be kept buttoned and pockets should be eliminated from the front of overalls and aprons. Trousers and overalls should not be turned up on the outside. For heavy work, fire-resisant leggings, high boots, or other equivalent means should be used. In production work, a sheet metal screen in front of the worker’s legs can provide further protection against sparks and molten metal in cutting operations. (5) Flameproof gauntlet gloves, preferably of leather, should be worn to protect the hands and arms from rays of the arc, molten metal spatter, sparks, and hot metal. Leather gloves should be of sufficient thickness so that they will not shrivel from the heat, burn through, or wear out quickly. Leather gloves should not be used to pick up hot items, since this causes the leather to become stiff and crack. Do not allow oil or grease to cane in contact with the gloves as this will reduce their flame resistance and cause them to be readily ignited or charred. e. Protective Equipment. (1) Where there is exposure to sharp or heavy falling objects or a hazard of bumping in confined spaces, hard hats or head protectors must be used. 2) For welding and cutting overhead or in confined spaces, steel-toed boots and ear protection must also be used. When welding in any area, the operation should be adequately screened to protect nearby workers or passers-by froman the glare of welding. The screens should be arranged so that no serious restriction of ventilation exists. The screens should be mounted so that they are about 2. 0 ft above the floor unless the work is performed at such a low level that the screen must be extended closer to the floor to protect adjacent workers. The height of the screen is normally 6. 0 ft (1. m) but may be higher depending upon the situation. Screen and surrounding areas must be painted with special paints which absorb ultraviolet radiation yet do not create high contrast between the bright and dark areas. Light pastel colors of a zinc or titanium dioxide base paint are recommended. Black paint should not be used. 2-3. FIRE HAZARDS a. Fire prevention and protection is the responsibility of welders, cutters, and supervisors. Approximately six percent of the fires in industrial plants are caused by cutting and welding which has been done primarily with portable equipment or in areas not specifically designated for such work. The elaboration of basic precautions to be taken for fire prevention during welding or cutting is found in the Standard for Fire Prevention in Use of Cutting and Welding Processes, National Fire Protection Association Standard 51B, 1962. Some of the basic precautions for fire prevention in welding or cutting work are given below. b. During the welding and cutting operations, sparks and molten spatter are formal which sometimes fly considerable distances. Sparks have also fallen through cracks, pipe holes, or other small openings in floors and partitions, starting fires in other areas which temporarily may go unnoticed. For these reasons, welding or cutting should not be done near flammable materials unless every precaution is taken to prevent ignition. c. Hot pieces of base metal may come in contact with combustible materials and start fires. Fires and explosions have also been caused when heat is transmitted through walls of containers to flammable atmospheres or to combustibles within containers. Anything that is combustible or flammable is susceptible to ignition by cutting and welding. d. When welding or cutting parts of vehicles, the oil pan, gasoline tank, and other parts of the vehicle are considered fire hazards and must be removed or effectively shielded from sparks, slag, and molten metal. e. Whenever possible, flammable materials attached to or near equipment requiring welding, brazing, or cutting will be removed. If removal is not practical, a suitable shield of heat resistant material should be used to protect the flammable material. Fire extinguishing equipment, for any type of fire that may be encountered, must be present. 2-4. HEALTH PROTECTION AND VENTILATION a. General. 1) All welding and thermal cutting operations carried on in confined spaces must be adequately ventilated to prevent the accumulation of toxic materials, combustible gases, or possible oxygen deficiency. Monitoring instruments should be used to detect harmful atmospheres. Where it is impossible to provide adequate ventilation, air-supplied respirators or hose masks approved for this purpo se must be used. In these situations, lookouts must be used on the outside of the confined space to ensure the safety of those working within. Requirements in this section have been established for arc and gas welding and cutting. These requirements will govern the amount of contamination to which welders may be exposed: (a) Dimensions of the area in which the welding process takes place (with special regard to height of ceiling). (b) Number of welders in the room. (c) Possible development of hazardous fumes, gases, or dust according to the metals involved. (d) Location of welders breathing zone with respect to rising plume of fumes. (2) In specific cases, there are other factors involved in which respirator protective devices (ventilation) should be provided to meet the equivalent requirements of this section. They include: (a) Atomspheric conditions. (b) Generated heat. (c) Presence of volatile solvents. (3) In all cases, the required health protection, ventilation standards, and standard operating procedures for new as well as old welding operations should be coordinated and cleaned through the safety inspector and the industrial hygienist having responsibility for the safety and health aspects of the work area. b. Screened Areas. When welding must be performed in a space entirely screened on all sides, the screens shall be arranged so that no serious restriction of ventilation exists. It is desirable to have the screens mounted so that they are about 2. 0 ft (0. 6 m) above the floor, unless the work is performed at such a low level that the screen must be extended closer to the floor to protect workers from the glare of welding. See paragraph 2-2 e (3). c. Concentration of Toxic Substances. Local exhaust or general ventilating systems shall be provided and arranged to keep the amount of toxic frees, gas, or dusts below the acceptable concentrations as set by the American National Standard Institute Standard 7. 7; the latest Threshold Limit Values (TLV) of the American Conference of Governmental Industrial Hygienists; or the exposure limits as established by Public Law 91-596, Occupational Safety and Health Act of 1970. Compliance shall be determined by sampling of the atmsphere. Samples collected shall reflect the exposure of the persons involved. When a helmet is worn, the samples shall be collected under the helmet. NOTE Where welding operations are incidental t o general operations, it is considered good practice to apply local exhaust ventilation to prevent contamination of the general work area. d. Respiratory Protective Equipment. Individual respiratory protective equipment will be well retained. Only respiratory protective equipment approved by the US Bureau of Mines, National Institute of Occupational Safety and Health, or other government-approved testing agency shall be utilized. Guidance for selection, care, and maintenance of respiratory protective equipment is given in Practices for Respiratory Protection, American National Standard Institute Standard 788. 2 and TB MED 223. Respiratory protective equipment will not be transferred from one individual to another without being disinfected. . Precautionary Labels. A number of potentially hazardous materials are used in flux coatings, coverings, and filler metals. These materials, when used in welding and cutting operations, will become hazardous to the welder as they are released into the atmosphere. These include, but are not limited to, the following materials: fluorine compounds, zinc, lead, beryllium, cadmium, and mercu ry. See paragraph 2-4 i through 2-4 n. The suppliers of welding materials shall determine the hazard, if any, associated with the use of their materials in welding, cutting, etc. 1) All filler metals and fusible granular materials shall carry the following notice, as a minimum, on tags, boxes, or other containers: CAUTION Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases. Use adequate ventilation. See American National Standards Institute Standard Z49. 1-1973, Safety in Welding and Cutting published by the American Welding Society. (2) Brazing (welding) filler metals containing cadmium in significant amounts shall carry the following notice on tags, boxes, or other containers: WARNING CONTAINS CADMIUM POISONOUS FUMES MAY BE FORMED ON HEATING Do not breathe fumes. Use only with adequate ventilation, such as fume collectors, exhaust ventilators, or air-supplied respirators. See American National Standards Institute Standard Z49. 1-1973. If chest pain, cough, or fever develops after use, call physician immediately. (3) Brazing and gas welding fluxes containing fluorine compounds shall have a cautionary wording. One such wording recommended by the American Welding Society for brazing and gas welding fluxes reads as follows: CAUTION CONTAINS FLUORIDES This flux, when heated, gives off fumes that may irritate eyes, nose, and throat. Avoid fumesuse only in well-ventilated spaces. Avoid contact of flux with eyes or skin. Do not take internally. f. Ventilation for General Welding and Cutting. (1) General. Mechanical ventilation shall be provided when welding or cutting is done on metals not covered in subparagraphs i through p of this section, and under the following conditions: (a) In a space of less than 10,000 cu ft (284 cu m) per welder. (b) In a roan having a ceiling height of less than 16 ft (5 m). c) In confined spaces or where the welding space contains partitions, balconies, or other structural barriers to the extent that they significantly obstruct cross ventilation. (2) Minimum rate. Ventilation shall be at the minimum rate of 200 cu ft per minute (57 cu m) per welder, except where local exhaust heeds, as in paragraph 2-4 g below, or airline respirators approved by the US Bureau of Mines, National Institute of Occupational Safety and Health, or other government-approved testing agency, are used. When welding with rods larger than 3/16 in. (0. 48 cm) in diameter, the ventilation shall be higher as shown in the following:

Thursday, March 5, 2020

The Development and Institutionalization of Slave Trade Essay Example

The Development and Institutionalization of Slave Trade Essay Example The Development and Institutionalization of Slave Trade Essay The Development and Institutionalization of Slave Trade Essay The Development and Institutionalization of Slave Trade BY vwoods 1987 Slavery, the condition of one human being owned by another (Slavery), has gone through many stages in its development and its reception around the world. As part of the Roman Empire in the 1st century BCE, slaves were a large part of civilized society as entertainers in the gladiator arena. These slaves would have been forced to compete, but with their victories and their deaths they would gain respect and some even their freedom. In Africa before the 16th century, slavery and systems of ervitude existed throughout the continent. African slaves during this time were often captives of war or indentured servants; however they were not treated with disrespect. Instead it was common practice for such slaves to be fully integrated into the village or tribe to which their owners belonged. Slaves would live side by side with their owners and could eventually become each others peers. It wasnt until the colonization of the New World and the spread of tobacco cultivation (Foner 101), began that the bond of slavery became less about the slave and more about cheap nd lifelong labor. As Eric Foner states in Give Me Liberty! An American History, no European nation embarked on the colonization of the New World with the intention of relying on African Slaves for the bulk of its labor force (101). Unfortunately, as the New World began to develop and expand its agriculture base, namely tobacco, that the demand for workers increased. European settlers originally had no plan to meet the labor request. Their first resort was to force Indian labor (Morgan 52). This plan began to unravel quickly however, since the Indians were easily susceptible to oreign diseases and began to die off before profits could be made (Morgan 53). It became clear that the Indian population would not support the labor force needed, and so the Europeans began looking elsewhere. Having considered other options, Europeans set their sights on Africa (Morgan 53). The nations of West Africa had had long standing relationships with the different European nations. In the early years of what would become the Trans-Atlantic Slave Trade, Spain and Portugal were the first nations to export slaves from Africa in great numbers. Records show that from the years 1500 to 1 550 over 64, 000 slaves were exported by these two countries alone (Number of Captives). These same records conclude that until the 1640s, Spain and Portugal were the only two countries with significant numbers in the slave trade. In 1619, the first Africans, twenty in all, arrived in Virginia (Foner 105), and with their arrival, the flood gates opened. It was at this time that other nations, namely Great Britain and the Netherlands, became more involved in the slave trade. The British and the Dutch began importing laves to the New World to meet the needs of the colonies. The British colonies of Virginia and Maryland, as well as the Dutch colony in New York, made up the Chesapeake area, with each having its own large tobacco industries that needed to be fueled by slave labor. By the turn of the century, the British and the Dutch had imported nearly 640,000 slaves to the colonies. With the importation of large number 0T slaves came more ana more laws tnat trlea to ratlonallze slavery as well to create a never ending supply of new slaves. Laws were passes regarding the birth of slave children as well as interracial children, with nearly all laws stating that if the mother was a slave that the child was a slave also, and became property of the slave owner. These laws consequently made sexual abuse of slave women profitable for slave holders (Foner 106). In such a short time Virginia had changed from a society with slaves, in which slavery was one system of labor among others, to a slave society, where slavery stood at the center of the economic process (Foner 108). Across the Atlantic, as stated efore, slavery was practiced throughout much of Africa among the various tribes and villages. However, with the increasing demand for slaves, coastal tribes would raid the inland tribes and capture their fellow Africans and sell them to the Europeans for small valuable trinkets. These newly captures slaves couldnt possibly have known what their futures held for them in the New World, if they made it there. Within the borders of the New World slaves tried to escape whenever possible, but rarely succeeded in such a new and strange world. Slaves newly imported were ubject to laws and customs that they didnt understand, and since many of them came from different villages few could communicate with each other (Marques). Slave rebellion was kept under control by the fierce and open violence aimed at those who stepped out of line. Fear for ones life suddenly became more important than freedom for many of the newly enslaved. As the years progressed the slave trade would see fluctuations in the number of slaves exported from Africa and imported to various countries as well as into the colonies, and then the United States of America. Political tensions, including the Revolutionary War, contributed to decline in slave importation but it wasnt until the 1831s that the slave trade essentially ended, at least for the United States. As History is bound to repeat itself, in recent times, there are numerous occasions were slavery has peaked and then declined. Fortunately these recent incidences, have never reached such catastrophic and saddening numbers as the Tran-Atlantic Slave Trade had. Foner, Eric. Give Me Liberty!. An American History. 3rd ed. Vol. 1. New York: W. W. Norton, 2011. Print. Marques, Leonardo. Slave Trading In a New World. Journal of the Early Republic 32. 2 Academic search complete. web. 4 oct. 2012 Morgan, Philip D. Origins of American Slavery. OAH Magazine of History 19. 4 (2005): 51-56. Academic Search Complete. Web. 4 Oct. 2012 Number of Captives Embarked and Disembarked Per Year. The Trans-Atlantic Slave Trade Database. Emory University, 2009. Web. 4 Oct. 2012. Slavery. Encyclop? ¦dia Britannica. Encyclop? ¦dia Britannica Online. Encyclop? ¦dia Britannica Inc. , 2012. Web. 10 Oct. 2012

Tuesday, February 18, 2020

Every Child Matters Literature review Example | Topics and Well Written Essays - 2000 words

Every Child Matters - Literature review Example The Children Act 2004 obliges schools and children's service agencies and other agencies, such as police, prisons and NHS trusts to protect children and promote their welfare. The agenda includes everything from "maltreatment, neglect, violence and sexual exploitation, accidental injury, and death, bullying and discrimination, to crime and antisocial behavior."   The areas of focus have been an educational failure, ill health, substance addiction, teenage pregnancy, abuse and neglect, crime and anti-social behavior among children and young people.The policy includes five main aims   of focus - be healthy, stay safe, enjoy and achieve, make a positive contribution to society and achieve economic wellbeing. The aims of the program have been good health (mental and physical, health lifestyles), skills development, community and society participation, economic well-being, creating Sure Start Children’s Centres in at-risk neighborhoods. The Sure Start children's centre programme offers early learning opportunities for children. The program is based on the belief that high-quality play and books at early age help in further learning effort at later stages of schooling. This helps to identify early learning abilities of children and prevent any possible defects. Along with other planned activities the policy aimed to boost child and adolescent mental health services (CAMHS) through creation of a Young People’s Fund. The policy also targets improvement of speech and language therapy. There are also many other activities planned to boost the level of child protection and development.