Biotechnology Essay Example | Topics and Well Written Essays - 750 words

Biotechnology - Essay Example (Paine, et. al., 2005). Another example is the BT corn, which genetically modifies corn crops to protect it from predatory pests such as caterpillars. Much controversy has surrounded biotechnology and biotechnology crops from the start. There are many critics argue that it worsens the lot of farmers rather than improve it because it creates a pattern of corporate dependence. Taking the BT-corn example, after some time, pests would develop a tolerance to modified strain in the corn crop and farmers will have no choice but to purchase new pesticides from the corporations at prices that will exploit their lack of choices. Environmental advocates, on the other hand, warn of the hazards of biotechnology on biodiversity and other life-forms. For example, environmentalists assert that the corn that is keeping pests away is also killing the Monarch butterfly. According to Kloppenburg and Burrows (2001), â€Å"given the increasing commodification of science and technology and the reality of where purchasing power lies, it is naive to expect a new tool such as biotechnology ever to fall outside corporate control.† 2. a. ... Because it is not possible to conduct research on human bodies, using animals in laboratory experiments is justified as a reliable way of ascertaining the risks to human health and to the environment. However, research involving animals must be done in a responsible manner so as to avoid any unnecessary cruelty upon the animals and to ensure that the laboratory experiments are done with the least possible damage to them or to other life systems. b. The dose-response curve refers to an x-y graph designed to measure the effects on a life-form or organisms as a result of exposure to stressors or chemicals, tested over a given period of time and in varying doses. The objective is to determine whether or not a certain chemical is beneficial, and the levels or doses that it is beneficial, as well as the doses at which it is already harmful. The dose-response curve is often used to aid in the crafting of environmental or health regulations. c. LD50 is the dose required to kill 50% of a samp le population within a given time frame. It is also called the median lethal dose. A low LD50 is dangerous because it means that only small doses are required to exterminate half of the sample. Conversely a high LD50 is conventionally deemed to be safer. The problem however with this baseline is that it only measures death and not other toxic effects that do not necessary lead to death. 3. I agree that the precautionary principle is an important environmental principle, and one that should be prevail over market considerations and free trade invocations. Scholars like Adler oppose the precautionary principle, as his problem with it was that it was not responsive to the threats of biodiversity

Child Development Essay Example | Topics and Well Written Essays - 1750 words

Child Development - Essay Example This report stresses that the childhood of the anti-socials had been full of negligence and deprival which has sucked out all their humanity and fellow feelings. Same can be said about children who spend their childhood in an orphanage where there is no one to specially care for each child. Such children spend a childhood of depression and when they grow up, often develop pessimistic approach towards life. Moreover, since the commencement of human civilization, human beings have learnt to depend on one another to satisfy their basic needs. Thus the nature of dependence on one another is the integral feature of mankind. Now, if a child is deprived of his right at the start of the life, this will obviously hamper the natural growth and development of its mind and consequently develop a sense of loneliness at a later stage in life. This paper makes a conclusion that proper care is very important for a child to help it grow up into an ideal human being and lead a normal life. This care must be selfless and unconditional in nature, which can only be expected from a child’s mother. Researchers have found how a traumatic and painful childhood can hamper the proper mental development of a child, sometimes even leading a person to develop negative feelings towards the society. This is why sensitive mothering is very important for a child.

Human Comfort Approach In Green Building Design

Human Comfort Approach In Green Building Design Recently, there has been an increasing emphasis on a green building design approach, which is aimed at ameliorating the overall impact of the built environment on human comfort and the natural environment. In this selective review, external , building envelope and internal factors will be examined in relation to human comfort. In particular, this project will focus on human comfort in regard to the importance and impact for day lighting, visuals and environment, material properties, protection factors, ventilation, thermal comfort, and access their effectiveness in the context of green building design. With regard to human factors, it is concluded that the impact of these factors on building occupants needs to be taken into account in advance in order to design a building which enhances the human health and well-being and consequently leads to the increase of productivity. Introduction Green building design approach is one of the global response to the increasing realization that the built environment contributes significantly to climate change over the entire buildings lifecycle. Building accounts for more than 40 percent of carbon dioxide emissions (Hegger et al. 2008). Moreover, the steadily rising energy cost over the past few years help to facilitate the trend towards sustainability. Taking into account these factors, energy saving measures have become a requirement in these days. End-users search for sustainable building concept, with low management cost and energy usage, which provides structures made from building materials that are in accordance with ecological point of view. Aside from looking at energy and operating cost, they also take an increasing concern in work performance levels. Only when people healthy and satisfy they can optimize their productivity (Bauer et al. 2007:11). Seeing these factors by necessity, means offering both a comfortable and healthy environment which is essential as a strategy to attract the investors and buyers. Still, there is no doubt that the comfort and well-being of humans is based to a certain extent on their subjective perception of some external influences (Hegger et al. 2008:55). Sassi (2006:101) seems to support this view and points out that people respond differently to situations and environments depending on their character and circumstances. Hegger et al. (2006) claims that the factors which will affect human comfort are basically categorized under physical, intermediary and physiological conditions. The purpose of this project is to examine the physical conditions with regard to human comfort and to focus on the building envelope, external and internal influencing factors. The importance and the impact of these factors on human comfort will then be examined, with a focus on the effectiveness in the green building design approach. Since the concept of this approach is increasingly put into practice globally, it is felt that this examination will highlight areas which need to be taken into account and will be integrated into the design process. 1.0 A Definition of Human Comfort and Green Building Design Human Comfort Human comfort can be broadly defined as the building occupants expression of satisfaction with the thermal environment (Yudelson 2007). Some of the parameters that affect the users comfort are as follows: environmental conditions (interior air temperature, lighting intensity and level of noise), physiological criteria (age, gender and constitution), intermediary conditions (clothing and activity) and individuals (Hegger et al. 2008:55). There is a connection between physical and psychological health. They are the factors that are highly likely to influence the human sense of happiness (Martin 1997). In turn, ones happiness will impact on peoples expectations, experiences and sense of self-worth. Humans generally wish to be accepted, respected and to feel secured. Therefore, it is essential for an architect to understand how people respond to the environment in order to design spaces which can enhance human health and well-being. Styles and types of building material, responses to individual building, light quality and atmosphere are linked to culture and personal memories which in turn linked to individuals character (Sassi 2006). For instance, a small space may feel comfortable to certain people but claustrophobic to others. It is difficult to design a building which would be universally appealing that enhances everyones well-being. Nevertheless, certain commonalities can be identified in regard to comfort and identity. Buildings should be designed to satisfy and fortify positive feelings as well as enable people to enjoy quiet moments of reflection and relaxation (Sassi 2006:137). It plays an important role in increasing occupants productivity and health in buildings. The building design could influence the human body mechanism to exchange heat with the environment through convection, radiation and evaporation (Hegger et al. 2008:55). As Bordass (1995) has pointed out that the elements which affect human comfort should be able to be operated and adjusted by the occupants. In other words, reduce heat loss yet sustaining good air quality is a necessity in terms of thermal comfort in building design for cold weather. Green Building Design Green building is always name as ecological building, sustainable building, or energy-efficient building. Green building design is a concept which emphasize on passive design strategy by making full use of day lighting, natural ventilation and allowing the insulated fabric and thermal to work effectively (Woolley 2008:181). A green building focuses on reducing building impact on the environment and occupants health while increasing the efficiency of resource use through better planning, design, construction, management and maintenance (Green building index organization 2009). To quote from the Department of Standards Malaysia (2007), a green building design approach is an strategy which united architectural, engineering, site planning, and landscaping so as to design an energy efficient building which would optimize the human comfort This approach makes an effort to optimize the advantage of the environment and to use building materials which is acceptable from a building ecology point of view. 2.0 External Factors Relevant to Human Comfort in Green Building Design Architecture and open spaces can help to define peoples identity and to define their territory. A good architecture can create special reference to the locality, high design quality and interactions between building and its environment (Hegger et al. 2008:102). Recognition of the locality help to promote responsibility with respect to the environment and human beings. Designing with emphasize on natural day lighting and visuals should begin at the preliminary design stage. By proving these, it can help to conveys a feeling of safety, belonging and security. 2.1 Day Lighting Day lighting is a significant factor for pleasant interior conditions. Without sufficient day lighting, people cannot perform well and healthy. Natural light stimulates humans organism and controls bodys functionality. It is crucial for our visual perception and has a substantial influence on our work efficiency (Hegger et al. 2008:102). Building materials which are transparent or translucent are essential if we wish to make use of daylight. However, it transmits heat as well as light. This in turn means that with more daylight, it reduces the dependence on artificial lighting, and the internal heat loads are decreased as well (Thomas and Garnham 2007:135). Conventional and innovative day lighting systems that collect, transport and distribute light deep into buildings and systems that reduce the need for artificial lighting are recommended. For building plans, this implies a design that is no more than 66 feet wide, about 33 feet length of front to back from any window to any workstation (Yudelson 2007:80). In other words, a buildings long axis should be oriented to east-west in order to allow a maximum day lighting from both south and north facing windows. The day lighting conditions over the course of the day influence the human hormone balance and synchronize our internal clock (Ander 2003). Thus, day lighting strategies, for instance, the orientation of the building, the proportion of window, the depth of the rooms, glare and ultra-violet (UV) protection, the design of reflective surface and the coloring of the enclosing components (walls, floors and soffits) are all the important design features. Passive and technical measures can be taken into account during design. Sunlight acts as a link that connect the building occupants with the outside world, facilitating our essential connection with nature and giving us a sense of time. It is important to realize that the mood or the perception of a space created by light is just as vital (Thomas and Garnham 2007:136).. To put it simply, people see and feel better whenever there is natural light for reading and working. 2.2 Visuals and Environment In green building design, emphasis is placed on providing outdoor views from all workstations. The research shows that if the occupants able to enjoy the outside view during the workday, it is more conductive to physical and mental health than working in a windowless environment (Yudelson 2007). Trees can help to absorb carbon dioxide from the air and store it as carbon. It can also provide shade to buildings, reducing heat gains and thus, improving the internal environment. In other words, contact with nature is beneficial to the well-being of humans. The building should be planned and designed so as to be visually as well as physically well connected with the outdoors. When designing the external works, emphasis should be put on to create and preserve natural habitats by providing extensive lawns, keep the area is natural state, trees and hedges, green roofs, and green facades. In some cases which the area of plot is small, rooftop planting can replace ground sealed by construction work. Environment plays an important role in satisfying basic human needs and quality of life. It can help to reduce stress and also can speed up recovery. In addition, it can affect humans on a psychological and physical level by acting as a recuperative and stimulating factor for our creative functions. In densely developed cities, it is critical for human health to strike a balance between making space accessible to people and preserving flora and fauna. According to some studies, dealings with nature will affect humans mental health, whereas leisure activities in nature directly benefit to physical health (Sassi 2006). 3.0 The Influence of the Building Envelope on Human Comfort in Green Building Design Building envelope acts as a boundary that separates between interior and exterior of a building through which thermal energy is transferred (Hegger et al. 2008:82). It also serves the function of protecting users and occupants against climate change such as solar radiation, precipitation and wind so as to create safe, healthy and secure interior space. However, the role of building envelope becomes more complex as the demand for comfort increases. A building should enable people to feel safe and comfortable by reducing potential dangers. To increase human comfort, the well-being and health of occupants in aspects such as material properties, safety and security, sound, interior air, and interior climate must be taken into consideration during design stage. 3.1 Material Properties The choice of material for building envelope will affect human comfort in the building. The designers should take great care when specifying materials in regards of the impact these materials have upon humans feeling about spaces and buildings. Functionality that reflect regional climate as well as cultural preferences, local vegetation and high-technology material need to be incorporated in the design. Materials are always describe as cold or warm. Based on scientific basis, metal for example, are good conductors of heat and therefore take the heat quickly from the body. On the contrary, wood is a poor conductor and hence feels relatively warm to touch. These physical sensation correspond to psychological states, such as a timber paneled room would feel warmer and more comfortable to inhabit than a predominantly metal one (Thomas and Garnham 2007:89). Different kind of wall material, construction and thickness are likely to differ in the value of thermal conductivity. U-value is a measure of the fabric heat loss which take into accounts mechanism like conduction, radiation and convection of heat transfer. The same can be said that the lower the u-value, the better the insulation the lesser energy needed to maintain comfort, the lower the environmental impact. Insulated walls reduce energy cost and increase comfort with levels of minimal effort (Thomas and Garnham 2007:102). To achieve sustainability in building design, consideration should be given to low embodied energy, material manufactured that is on waste, easy to disassembly and used to recycle in the end of the building life span, transportation to the construction site and strategies or method that are often used in architectural practice. 3.2 Protection Factors on Occupants Well Being and Health Building should keep users safe and secure both within the building and its environment by protecting them from accidents, intruders, fire, and natural dangers. Accordingly, contributions to the subjective perception of safety and secure by providing a good layout, lighting, social controls, presence of other people and good visual links are necessary (Hegger et al. 2008:195). A designer can provide these features by considering the specification of material, fire protection concept, natural dangers, clarity and peoples activities during design stage. Creating pleasant acoustic conditions is also one of the important protection factors. Noise pollution and acoustic conditions will influence the well-being of people and can affect their health. Noise between usage units and plus disturbance such as noises from building services and unfavourable room acoustic should be avoid through precautionary building physics and room acoustic measures. Constructional sound insulation and room acoustic measures should be included in the room acoustics report as a guidance. Besides the above aspects, interior air and climate are also the fundamental elements to increase the well-being and health of the occupants. A poor interior air quality will cause some bodily symptoms and lower the productivity (Awbi 2008). Moreover, thermal comfort has a major influence on the human heat balance and direct effect on energy consumption of buildings. It should be optimized through constructional and passive measures. For example, it can be done through specifying the construction methods, thermal insulation, moisture control, coordination of window proportion, ventilation concept and also the protection against overheating by providing sun shading devices. 4.0 Internal Factors Which Support Human Comfort in Green Building Design The primary function of building is to provide a suitable internal environment for the purpose of the building. According to Boubekri (2008), the effects of poorly designed buildings, whether in terms of limited natural ventilation or poor thermal comfort, would affect the health of building occupants. In order to achieve an acceptable level of human comfort, the indoor environment for human implies a temperature between 16 to 25 degree Celsius. 4.1 VENTILATION Natural ventilation is another approach which will provide a healthy and comfortable internal environment by removing polluted indoor air and replace with the fresh air from outside through openings. It would be cosy if the air can be circulated naturally from the outside to the inside of the building (Hegger et al. 2008:101). People will have sensations such as the warmth of the unfiltered sunlight, smells and acoustic stimulus by direct contact with outside air. It can have a positive effect on the quality of the habitable room, in that, natural ventilation system are particularly user friendly from the emotional pint of view (Hegger et al. 2008:99). Thus, habitable rooms should always include opening the facade whenever possible. There are three main mechanisms in natural ventilation, for instance, single sided where air comes in from a window, cross ventilation where air crosses a space from one side to another which the effect of wind pressure causes the air to enter on the windward facade and pass through the building and lastly providing a stack effect exiting path, resulting from the temperature differences between the indoor and outdoor air, where the hot air rises and exits the opening near the roof or providing openings at the 2 sides of the wall. According to Department of Standards Malaysia in MS1525 (2007), cross ventilation is defined as the flow of air through a building due to a wind-generated pressure drop across it. These processes are natural and are provided by pressure gradients and temperature differentials which in turn create pressure differences (Thomas and Garnham 2007:116). They do not required large quantities of energy to run the powerful fans which used in mechanically ventilated buildings. Natural ventilation is the most energy efficient way of supplying essential fresh air to a building. When it is insufficient, then other cooling options may be possible. 4.2 THERMAL COMFORT According to Flynn and Segil (1970:80), human body functions as a heating and cooling mechanism. It can, to some extent, efficiently and automatically adjust to the environmental conditions that vary from optimum. Our body functions to lose heat at a certain rate to reasonably cooler air and surfaces. Nevertheless, if such action is either too slight or excessive, it will lead to occupant discomfort and physiological stress. Human heat balance, humans body temperature, needs to be around 37ÂÂÂ °C; this is a prerequisite for well-being. Humans emit heat through the following mechanisms: firstly by exhalation and through evaporation of skin, secondly by covection of heat from body surface to the surrounding air, thirdly by conduction of heat from the body to immediate objects and lastly by radiation of heat to the nearby objects and the surfaces enclosing the room (Hegger et al. 2008:55). On the other hand, heat transfer in building in three modes, which are conduction, convection, and radiation (Moe 2010:9). If the temperature of surrounding area drops, the body will first allow the extremities to cool in order to protect the functions of brain, heart and other vital organs (Hegger et al. 2008:55). It is essential to transfer the internal heat generated to the environment in order to get a constant temperature. If the temperature of the interior air is not consistant, the risk of accidents increases and manual dexterity, productivity and mental abilities decrease quickly. In regards of this, a thermally comfortable environment is primarily due to physical influencing factors such as the temperature of the interior air and the average temperature of the external air, the humidity of interior air and the movement of the air (Hegger et al. 2008:56). Building functions to admit and conserve heat when the external environment is cold and to thwart the penetration when the external environment is warm. Conclusion Human comfort is not only a strategy in green building design for the purpose of attracting the investors and buyers, but also an approach which determines occupants health and well-being. This paper has discussed the factors that contribute to human comfort and has briefly presented the importance and the influence of the factors towards peoples comfort in certain aspects of building design. These included the building envelope, interior and exterior factors which consist of day lighting, visuals and environment, material properties, protection factors, ventilation, and thermal comfort. The effectiveness of the approach towards users comfort has also been highlighted, particularly with regard to the human comfort and well-being lead to the increasing of productivity. In discussing the effectiveness of the approach, it has concluded that although the desired degree of comfort can be a highly subjective perception, some commonalities can be identified. This can assist in optimizing the design for a better human comfort. Green buildings always offer a high level of comfort and healthy indoor climate while depending on renewable energies and low energy embodied resources ( Bauer et al. 2007). It should be noted that human comfort is only one of the approach in green building design. Other approaches such as energy efficiency and renewable energy should be taken into account in design , however, are lied outside the parameters of this paper due to the limited scope and a more thorough research could be done in this area. This would be particular interest to the professionals who incorporate the environmental engineering studies in their design.

The California Justice System :: Argumentative Persuasive Essays

The California Justice System It is 3:14 in the afternoon here at University, prestigious institution of higher learning. Sitting here in my room relaxed and content [at least until I realize that midterms are around the corner], I gaze out onto the picturesque courtyard of my dorm, Lagunita Court; uniquely defined by its rich architecture and serene atmosphere. Like most days, the sun is shining brilliantly, radiating a positive energy across the campus, as if God had chosen life to spring from these very grounds. This type of â€Å"winter† weather is unquestionably exclusive to those lucky enough to live in California, justifying the choices made by many students, myself among them, to further pursue their educational goals as a Cardinal. As I continue to sit in my chair, I begin to stare at the reflection on the window. I notice behind me the small, cramped space I call my dorm room. I think about how I would not be capable of staying inside the vicinities of these four walls for an extend ed period of time, feeling confined with no opportunity to fully develop and meet my potential. Today I received a letter from my cousin Duc . It had been awhile since I last heard from him, so it was nice to find his name on a letter rather then â€Å"Chase Credit Card Billing/Payment†. The letter starts off, â€Å"Sup lil’ bro. Just wanted to write to say thanks for the photos from X-mas and your letter†¦sounds like you had a good holiday break. And I’m happy that school has been going well for you.† He continues on asking about my life eventually discussing news/current events [his favorite as of late has been the politics of Governator Schwarzenegger]. He ends the letter letting me know that he is doing fine. â€Å"There’s nothing much going on here. Just got off lockdown Thursday. Went out to yard once and have been kicking it ever since. Maintaining as usual. Keeping it short this time†¦Take care. Love you, Duc Ta.† My cousin Duc, 21 years old now, is in prison. He has called the roughly 10’x 8’ cells home for the last four and a half years. Currently, he is being held in the New Corcoran State Penitentiary, having been relocated from the Tehachapi Correctional Institution [a euphemism in every sense of the definition] a few months ago. The California Justice System :: Argumentative Persuasive Essays The California Justice System It is 3:14 in the afternoon here at University, prestigious institution of higher learning. Sitting here in my room relaxed and content [at least until I realize that midterms are around the corner], I gaze out onto the picturesque courtyard of my dorm, Lagunita Court; uniquely defined by its rich architecture and serene atmosphere. Like most days, the sun is shining brilliantly, radiating a positive energy across the campus, as if God had chosen life to spring from these very grounds. This type of â€Å"winter† weather is unquestionably exclusive to those lucky enough to live in California, justifying the choices made by many students, myself among them, to further pursue their educational goals as a Cardinal. As I continue to sit in my chair, I begin to stare at the reflection on the window. I notice behind me the small, cramped space I call my dorm room. I think about how I would not be capable of staying inside the vicinities of these four walls for an extend ed period of time, feeling confined with no opportunity to fully develop and meet my potential. Today I received a letter from my cousin Duc . It had been awhile since I last heard from him, so it was nice to find his name on a letter rather then â€Å"Chase Credit Card Billing/Payment†. The letter starts off, â€Å"Sup lil’ bro. Just wanted to write to say thanks for the photos from X-mas and your letter†¦sounds like you had a good holiday break. And I’m happy that school has been going well for you.† He continues on asking about my life eventually discussing news/current events [his favorite as of late has been the politics of Governator Schwarzenegger]. He ends the letter letting me know that he is doing fine. â€Å"There’s nothing much going on here. Just got off lockdown Thursday. Went out to yard once and have been kicking it ever since. Maintaining as usual. Keeping it short this time†¦Take care. Love you, Duc Ta.† My cousin Duc, 21 years old now, is in prison. He has called the roughly 10’x 8’ cells home for the last four and a half years. Currently, he is being held in the New Corcoran State Penitentiary, having been relocated from the Tehachapi Correctional Institution [a euphemism in every sense of the definition] a few months ago.

Manufacturing Plan For Wing Of PAV

Manufacturing processes are differed according to the fabrication techniques such as sheet metal forming and machining processes. For the wings of a new personal air vehicle (PAV); skins ands ribs are produced by sheet metal forming process and spars are produced by machining process. Finally all produced parts are assembled together to produce final wing structure. In addition, since the components that build up ailerons and flaps are very similar to wing structure, manufacturing techniques applied for skins, ribs and spars are also valid for them. Since there should be actuator and hinge fittings to connect ailerons and flaps to wing structure, they are considered in machined parts manufacturing process section. SKIN MANUFACTURING Manufacturing process of skins is shown in Figure -1; Figure-1 [1] Tools for sheet metal forming Operations; Stretching Dies, Drill fixtures, drill plates, holding tools First Cut Aluminums Raw Materials are cut by shearing machine or hand router to get available sizes for manufacturing with much enough excess portions. Heat Treatment Blanks are then solution heat treated to provide necessary mechanical properties to the parts. Heat treatment operations are done according to the design requirements which are defined by engineering drawings. Heat treatment processes are applied to make parts generally T4, T5 or T6 tempers. Stretch Forming – Skins On the stretch press, skins are stretch formed and their tooling holes are marked. After removing the skins from stretch presses, the marked tooling holes are drilled for succeeding assembly operations. An example of stretch forming process is shown in Figure – 2. Figure – 2 [2] Skin Routing Routing operation could be done with two techniques; The first one is using a routing shell tool which has two parts which have exactly same form of the skin. The skin is then located in between them which is fixed with the tooling holes previously opened after stretching and a hand router is traveled around the tool to shape the skin to its final contour. A photo of a router shell is shown in Figure – 3. The second technique is using a five axis gantry routing centre with flexible vacuum assisted table. The skin is positioned with the aids of vacuum assisted columns as shown in Figure -4 and tooling holes are used to set the machining coordinate axes. Figure – 3 [3] Figure – 4 [4] During routing operation, tack holes are also drilled. Also during routing operation, excess portions like access openings or some pockets are removed from the skin. Surface Treatment Surface treatment operations are also defined by the engineering drawings. Some of the surface treatment operations applied are rinsing for cleaning, chromic acid anodizing, primer and coating for corrosion prevention. Primer coating and painting are also called as Chemical Conversion Coating (CCC) which is beneficial for fatigue prevention. In our case, chromic acid anodizing is applied to 2024 skins for preventing corrosion and paving the way for painting. Before chromic acid anodizing, fine holes should be masked to keep dimensions accurate. A typical anodise process would consist of a solvent wash and/ or an alkaline clean to remove any oils or greases from the surface. followed by a de-oxidiser stage to remove the natural oxide film from the surface, followed by chromic acid. This gives you a clean oxide free surface which once anodised will give better adhesion of the anodised layer. There is a water rinse stage between each tank to prevent contamination of the bath solutions. From there you have two choices, spray directly onto te anodise ‘honeycomb' structure which will give good paint adhesion, or seal the anodised layer for enhanced corrosion protection but poorer paint adhesion. Painting Finally, primer, top coat and final paint are applied on the skin. RIB (SHEET METAL) MANUFACTURING Manufacturing process of ribs is shown in Figure – 5; Figure – 5 [1] Tools for sheet metal forming Operations; Hydro press forming dies, Drill fixtures, drill plates, holding tools The main difference of manufacturing of ribs from skins is hydro press forming process instead of stretch forming. Hydro press Forming After heat treatment, blanks become ready to be formed. In aerospace industry fluid cell forming (hydro press forming) is frequently used for forming operation. That is mostly because of the reality that aircraft parts are manufactured in small quantities and parts are mostly different in geometry. Therefore it is necessary to manufacture a different tool for every part and that is very costly. Although the machine is quite expensive, to decrease the tooling costs, hydro press forming is preferred since only male dies are necessary to form parts instead of male-female die combination. That is illustrated in the figure. Also another advantage of hydro press forming is that, on the table of the press machine, several tools, with the blanks on them, could be located randomly at once. In one cycle all the parts are formed simultaneously. Also in general press machines are equipped with two tables which make it possible to decrease set up time to half. Some photos related with hydro press forming are shown in Figure – 6. Figure – 6 [4] SPAR, HINGE, RIB AND FITTING MANUFACTURING Manufacturing process for machined parts, spars, hinges, ribs and fittings is shown in Figure-7; Figure – 7 [1] Tools specific to machining operations; Milling fixtures Machining If necessary those parts which will be machined on milling centers, are firstly cut from blocks of raw material to their required stock sizes. They are mostly skin milled. Skin mill is done to obtain a smooth flat plane to locate the stock on the milling machine table. After skin mill, some holes are drilled on the stock for the sake of transportation and fastening on the machine tables or fixtures. For complex milling operations in which there are more than one stages of operations, it is common to use a milling fixture, see Figure -8. Another reason for use of milling fixtures is that in aerospace industry manufacturing tolerances are so tight and geometries are mostly very complex that is why it is necessary to provide same machining conditions and set up for every single part. Milling fixtures are tools, on which stock material is located and clamped. Their main functionality is that they hold the machined part tightly throughout the machining process which prevents machining def ects and dimensional inaccuracies. , Figure – 8 [4] To obtain required dimensional tolerances, some holes require boring. Boring operation removes only a small quantity of material therefore before boring operation the hole must be drilled very close to the final dimension of the hole diameter. Dimensional accuracy of the machined parts are generally checked with the utilization of Coordinate Measuring Machines (CMM). These machines are very precise such as they are capable of measuring ten thousands of a millimeter in three dimensional spaces. Although they are quite expensive and they need an air conditioned, humidity controlled and vibration isolated chamber, they are the most accurate and flexible measurement equipments. Shot Peening Machined parts are exposured to shot peening operation. That process is done to remove and minimize the existing surface cracks on the machined parts. Machined parts are generally bear high amount of repetitive tensial and compressive loads and these repetitive loading is mostly the main cause of fatigue failure. Surface cracks are the mostly affected defects from repeated loading and they tend to grow under these conditions. That is why they must be removed or minimized to prevent them to grow and increase the fatigue durability of the part. Surface treatment As explained before both chromic acid anodizing, primer coating and painting are the surface treatment operations applied on the parts to make them resistant to corrosion. Another advantage of these chemical conversion coating processes is that they make the part more durable to the fatigue, since they penetrate to surface cracks, scratches and holes. For instance, pitting is a corrosion type which is more susceptible to such surface defects. Therefore surface treatment processes both provide a protective coating in corrosive environments and they generate a smoother aerodynamic surface, which is a requirement to decrease air drag, especially for the outer surfaces which are in contact with the air during flight. ASSEMBLY OPERATIONS Assembly Operations are shown in Figure – 9; Figure – 9 [1] Tools for assembly operations; Assembly and sub assembly jigs and fixtures Assembly Jig In aerospace fabrication processes, since the parts have very complex geometries and position tolerances are so tight, it necessary to use a fixture to locate parts in their required positions and apply assembly joining operation in these positions without letting them to move. For an air plane wing a single assembly jig could be used for this purpose, see Figure – 10. Figure – 10 [5] Spars are located on the jig. They must have a planar smooth contact surface and they must have previously opened tooling holes. Those holes are used to pin the spar on the jig and some clamps are used to fix the spar in its position. Ribs are located. They are installed on the jig with the utilization contacting surface of spar and some other location surfaces and they are pinned from their tooling holes. Clamps are used to fix ribs in their location. Some of the holes are transferred from ribs to spars or the contrary. Bottom skin is loaded on the jig by the aid of tooling holes on the lugs at each lateral short edge. To wrap the rib spar assembly the skin could be pressed by some belts or some header plates could be used to bring the skin to its required form and clamp it to hold it in its required position. Some of the tack holes on the skin are fastened with clecos, which is a temporary fastener. Pilot holes are drilled to their final sizes and countersinking is applied to locations where countersunk rivets and bolts will be used. After drilling and countersinking is applied parts are separated to remove chips. Before putting parts together again, sealant is applied. Sealant is a viscous chemical isolation material which is a polymer in general (polyurethane, polysulfide, etc). It is applied when it is still in fluid form and it solidifies as a result of chemical reaction which takes place as soon as the sealant is exposed to air. They are used to prevent fluid leakage into internal structural components. This leakage could result catastrophic failure since corrosion which erodes material would work against the mechanical strength and stiffness of the structure. For different purposes and for different locations specific types of sealants are applied. For instance polysulfide based sealant is applied to the surfaces where there is fuel content. For fuel tanks these polysulfide based sealants are used since they withstand the attack of sulfur compounds that are present in fuel. After sealant application, outer skin is brought to close the wing and it is fastened with blind rivets and bolts since it will only be possible to reach rivet from one side. When riveting and bolting completed the wing is removed from the assembly jig and it is sent to paint shop for the application of top coating and painting. After that manufacturing and assembly operations will be completed.

Great expectations Essay

Dickens engages his audience by creating vivid images of people and places. Comment on this with close references to two parts in ‘Great Expectations. ‘ The two sections I will be referring to are chapter 1 and chapter 8. In these chapters Dickens describes two different settings; the church yard and Satis house. He also introduces us to Philip Pirrip known as Pip. Pip’s ambition is to become a blacksmith. Magwich is an escaped convict. Estella is Mrs Havisham’s ward. Mrs Havisham is a rich but heartbroken woman who despises men due to her own marriage breakdown. In the opening chapter, Dickens describes the marshland and the graveyard. The impression I get of the setting is unwelcoming and desolate. He describes the marshland as a damp swamp with unfriendly plants such as stingy nettles. He also describes graveyard as a dark gloomy surrounding with little warmth and hospitality ‘a man soaked in water, covered in mud†¦.. as he seized me by the chin. ‘ Charles Dickens describes the atmosphere as a raw afternoon with the help of the weather. He achieves this with the help of creative weather descriptions throughout the fist chapter ‘†¦ which the wind was rushing†¦.. and that small bundle of shivers growing afraid of it all†¦. ‘ Although the scene is serious, Dickens still manages to bring humour into it. For example: when pip was tilted upside and robbed off a stale piece bread. ‘The man, after looking me for a moment, turned me upside down and emptied my pockets. ‘ I think dickens added humour to dilute the tension and to give us a laugh. He also introduces us to pip and Magwitch, the convict. Pip feels intimidated by the convict, due to the way the convict enrols power over pip as he tilts him down on top of the grave. ‘†¦ so that his eyes looked most powerfully down into mine, and mine looked most helplessly up into his. ‘ We feel pathos for pip as Magwitch verbally threatens pip with no regrets. Magwitch is describe as a fearful man, a man with no hat, soaked in water and smothered in mud. The impression we get from the description of Magwitch is that he wasn’t gentlemen due to no hat. We feel empathy for the convict as we get a strong description of what he has been through. ‘A man soaked in water, and smothered in mud, and lamed by stones, and cut by flints, and stung by nettles†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ seized me by the chin. ‘ In chapter 8 Pip, again, feels uneasy when he visits Satis house. It is described as a dark, uninviting resident with old bricks, iron barred windows and a courtyard that is also barred. The atmosphere portrayed to us is that Satis house is an unappealing place to visit. Dickens creates this atmosphere detailed information and through the characters thoughts and feelings. Pip meets Estella and Miss Havisham at Satis house. He is surprised by Miss Havisham’s appearance. She is dressed in an outfit that can only be worn only on one particular day and that was her wedding dress. We learn as we read on, she is dressed in her wedding gown as she believes her husband, who fled on the wedding day, would come back and wed. We assume that pip is having second doubts of the arrangements and is cautious of behaviour. The impression we get of Miss Havisham is she is an aged but rich woman who despises men due to her marriage failure. Nevertheless she puts her misfortunes a side and treats pip kindly. Estella, by contrast, is a young, vibrant girl but has a bad attitude. She treats pip as an inferior with no respect at all. One major example was when she referred to him as ‘boy’. †¦ ‘but do not loiter, boy. ‘ Pip reacted in polite way no matter what she said. We see Estella as a rude and spiteful child. Dickens is successful in creating different settings by giving the readers detailed description of the setting and through the characters thoughts and feelings. Dickens has drawn on his own experiences and this is why he is successful.

Annodated Bibliography essays

Annodated Bibliography essays 1. Congressional Record House. Congressmen in near fight. Page 9552 May 20,1924. Washington: U.S. house, 1924. Congressman Mclafferty (R) of CA and Howard (D) of Nebraska almost come to a fist a cuffs over objecting to procedure. The gentlemen both had issue the wished addressed before the brake of the early session both charged the other but other congressmen kept them apart. 2 Congressional Records House. Venereal disease in the District of Columbia, address of bill H.R. 491 sec.2 68th congress 1st session may 14 26 1924. A dictated description of a session of congress in which, the issue of Soldiers declaring that they have a venereal diseases to the judge before appearing in court. The report cites health officials form the board of health in Indiana. He makes claims that out of 28 boys inducted into the service 27 have a venereal disease. He would cite Venereal diseases as the greatest destroyer of mankind. 3. Congressional Records House. Shadow boxing with Religion. Page A4602. Oct 10, 1941. This article is a rebuttal to the comments made by the president from Hon. Henry C. Dworshak. The article spoke on the claim that religious freedom in the Soviet Russia was equal to that of religious freedom in America. The comments made by the president were made in hopes of unifying an alliance with Soviet Russia and America. 4. Congressional Records House. Observations from Washington, exstention of remarks. October 27, 1941. A description telling of the christening of the new USS Indiana. The report also tells of the increases of civilian employment during wartime for military production. A plan is also laid out that describes the military recruitment of civilian companies for wartime production. 5. House of commons Great Britain Sessions Papers. Page 43. 1854 1845 Table showing the number of persons committed or bailed for trail, charged wit...