Conceptual framework Essay Example for Free

Conceptual framework Essay The table1 below shows that the theories for the adoption and diffusion of an IT-based innovation. Scholar name: Theory name 1. Rogers (1983, 1995) Innovation diffusion theory 2. Moore and benbasat (1991) Perceived characteristics of innovation 3. Davis (1989) Technology acceptance model 4. K won and Zmud (1987) Diffusion/ implementation model 5. Fishbein and Ajzen’s (1975) Theory of Reasoned Action (TRA) Table1 2, a list of innovation adoption theories. Davis developed the technology acceptance model in 1989. It aims to explain the determinants of computer acceptance in general the capability of the user’s behavior across a broad range of end-user computing technologies and user populations, while being parsimonious and theoretically justified (Davis 1989). The theory includes several theoretical backgrounds like adoption of innovations, the cost-benefit paradigm, expectancy theory, and self-efficacy theory. At the core of the theory is the model proposed by Davis, which focuses on the perceived usefulness of technology and perceived ease of use, which plays a significant influence in adopting innovation. Figure 1. Davis Technology Acceptance Model Davis’ TAM originated from the Fishbein and Ajzen’s Theory of Reasoned Action (TRA) model (Davis, 1989). The TRA model aims â€Å"to explain a broader range of behaviors based on situation specific combinations of personal beliefs and attitudes, and the effects of beliefs of others close to the individual† (Szajna, 1996). The discussion and limitation of the theories A limitation has been found for using those theories is that â€Å"according to the research, there are only the Innovation diffusion theory (Roger, 1995) and Diffusion/ implementation model (K won and Zmud, 1987) predict the both of an individual’s adoption behavior and an organization’s adoption behavior. † (Anand Jeyaraj, Joseph W Rottam, Mary C Lacity). The others theories predict only an individual’s adoption behavior. In another words, the TAM and TRA only exam the innovation adoption from the individual blogger perspective. However, to eliminate the limitation, the author will choose using with the DOI theory together in order to deeply analyze the both innovation adoption by individual bloggers and organizations. Diffusion and Rogers’ Diffusion of Innovation Theory 1995 Diffusion is the process in which and innovation is communicated through certain channels over time among the members of a social system. It is a special type of communication, in that the messages are concerned with new ideas (Rogers 1995, 5). In his works, Rogers discusses diffusion as the transfer of innovations through different media in a specific time and into different members of the social system. He also defines communication, an important and critical part of the diffusion of innovations. He defines communication in the diffusion of innovations as a process in which participants create and share information with one another in order to reach a mutual understanding. This definition implies that communication is a process of convergence (or divergence) as two or more individuals exchange information in order to move toward each other (or apart) in meanings that they give to certain events (Rogers 1995, 6). Communication is a very important factor in the diffusion of innovations, it is a medium which must be perceived as a two way process rather as a one-way linear act, since in the diffusion of innovations, those who are yet to accept the innovations must be well adept and informed about the innovation. Blogging is a form of innovation which involves the interaction of a whole social system in the dynamic cyberspace. Corporate blog is seen as a communication method which involves the interaction of two or more individuals or even a whole social system. Diffusion is a special type of communication in which the messages are about a new idea. This newness of the idea in the message content gives diffusion its special character (Rogers 1995, 6). From these statements come new concepts such as newness, uncertainty, and information in the context of diffusion. While uncertainty is the degree to which a number of alternatives are perceived with respect to the occurrence of an event and the relative probability of alternatives. Uncertainty implies a lack of predictability, of structure, and of information. Rogers (1995) cites Rogers and Kincaid (1981) in the discussion of Information in the context of diffusion. Wherein, Information is a difference in matter-energy that affects uncertainty in a situation where a choice exists among a set of alternatives. Advances in technology, embodies information and reduces uncertainty about cause-effect relationships in problem solving. Technology is information put into use in order to carry out some task (Rogers et. al. 1999, 689) As technological advances are the major factors diffused, studies have also been conducted in relation to technological transfers which is much related to the diffusion of innovations. Technology transfer is the application of information into use (Rogers 1995). As defined, technological transfer is the application of theoretical innovations into applied inputs and outputs which may be used for both commercialized and not commercialized produce or services, wherein consumers or corporations benefit. The information that is transferred results from research that is conducted, perhaps in order for it to be applied to the development and commercialization of new or improved products or services that are sold in the marketplace by private companies (Matkin 1990). The process of technological transfer involves an interaction between the corporation and the corresponding stakeholders which benefit or which are affected by the corporation. Thus the suggestions in Rogers’ theory that there must be clear coordination through communication should be applied as reinforced by Williams and Gibson. The technology transfer process usually involves communication between (1) a source of technology that possesses specialized technical skills, and (2) receptors who do not possess these specialized skills and who cannot create the technology themselves (Williams Gibson 1990). Which is basically corresponding to the logical flow that technology is basically transferred to those who are not well adept to the advanced technology. A technology is a design for instrumental action that reduces the uncertainty in the cause-effect relationships involve in achieving a desired outcome (Rogers 1995, 13). Technology often has two aspects, one is the hardware aspect and the second is the software aspect. The hardware aspect consists of a tool that embodies the technology as a material or physical object (Rogers 1995, 13). The hardware aspect often comes as the solid part of the technology, as in the case of the computer, the hardware aspect is the keyboard, the monitor, the mouse the central processing unit, semiconductors etc. The software aspect consists of the information base for the tool (Rogers 1995, 6). The software aspect is then composed of the tools which enable the hardware to pursue its functions. As in the case of the computer, the software aspect is the codes, programs, commands, instructions, manuals, etc. Contrary to the common perception that the hardware is mostly is technology since it is normal for humans to think only of things which they can see and hold – yet technology may be purely the software aspect or may entirely be composed only of information which is new and considerably helpful than the current design and functions of normal practices. Examples of these technologies which may be composed of pure information are political ideologies such as Marxism and Maoism; and or religious beliefs and ideas such as Hinduism, Buddhism, Islam, etc. Corporate blog may be attributed to the software part, as there is no solid hardware present, but the computers and other equipments. It is an easy way to make organizations adopt to innovations, such technology existed for quite sometime yet there are yet a few corporations who did not join the trend of corporate blogging. Everett Rogers conceptualized the Diffusion of innovation theory in 1995. In this theory, Rogers (1995) points out that the acceptance of an innovation depends upon certain qualities as perceived by the audience. These qualities are the relative advantage of the innovation, its compatibility with existing values and practices, its simplicity and ease of use, its trialability, and its observable results. Relative advantage is the degree an innovation is perceived as a better idea than its preceding innovations. This quality is measured in economic terms, social prestige, convenience and satisfaction (Robinson, no date). Robinson further stresses that â€Å"the greater the perceived relative advantage of an innovation, the more rapid its rate of adoption is likely to be†. Compatibility with existing values and practices is concerned with the consistency of the innovation to the existing values, past experiences, and needs of potential adopters. If an idea is perceived to be incompatible with existing values and practices of a social system, it is less likely to be adopted. Simplicity and ease of use is the adopter’s perception on the difficulty of the innovation to understand and use. The simpler the innovation, the more rapid its rate of adoption will be. Trialability is the degree an innovation may be experimented with on a limited basis (Robinson, no date). Trialability of an innovation reduces the potential adopter’s uncertainties about the innovation. Observable result is the degree to which an adopter sees the results of an innovation. The more visible the result is, the more likely individuals will adopt it. These are the factors that must be considered in order to create a successful innovation. In summary, innovations simply with more relative advantages, greater compatibility, trialability, observability, and less complexity will gain a higher rate of adoption. There are four main elements in the Diffusion of Innovations as identified by Rogers (1995), these are (1) Innovation, (2), Channels, (3) Time, and (4) social system. As defined earlier, Rogers (1995, 11) defines diffusion as the process by which (1) and innovation (2) is communicated through certain channels (3) over time (4) among the members of the social system. Innovations. An innovation is an idea, practice, or object that is perceived as new by and individual or other unit of adoption. I matters little, so far as human behavior is concerned, whether or not an idea is â€Å"objectively† new as measured by the lapse of time since its first use or discovery (Rogers 1995, 12). As Rogers (1995, 12) stresses, it should be assumed that the diffusion and adoption of all innovations are necessarily desirable. The attributes of innovations are namely, (1) Relative advantage, (2) Compatibility, (3) Complexity, (4) Trialability, and (5) Observability. Rogers (1997, 2) discussed each of the five attributes; Relative advantage is the degree to which innovation is perceived as better than the idea it supercedes. Individuals evaluate new ideas in relationship to the ideas with which they are familiar; compatibility as the degree to which an innovation is perceived as similar to the individual’s past experiences, values and beliefs; Complexity as the degree to which an innovation is perceived as difficult to understand and use; Trialability as the degree to which an innovation is perceived as divisible by the individual for purposes of gaining personal experience with it; and observability as the degree to which an innovation is perceived as highly visible to others.

Ohio State University Essay Example for Free

Ohio State University Essay Cynthia Ozick is a daughter to Celia Regelsion and William Ozick who was born on 17th April, 1928 in New York. She has a strong educational background. She is a BA degree holder from the university of New York and Masters degree (MA) holder from Ohio State University. She is a respectable and an outstanding writer who has written several fictions and essays and particularly on the life of Jewish Americans. Some of her works such as the novel entitled ‘Heir to the Glimmering world’ that was released in 2004 made her to become popular in the world especially in the United Kingdom. Ozick has achieved many awards due to her unmatched writing skills for example she won the 1986’s Rea Award for the short story writer. She was also on the limelight in 2005 when she won the Man Booker International award. As if this was not enough, she won herself the PEN award in honor of her excellent short story writing skills. Her writing career did not occur to her overnight in fact there are some historical factors that motivated and shaped her life to what she is now. This research paper is going to delve deeper into Cynthia Ozick’s historical background and try to establish the exact factors that influenced her to become a writer of her caliber. The paper will also give brief background information of her life and then conclude with a quick summary of the main points that have been discussed. In the very last page of this paper is a list of all the resources that have been consulted while conducting this research and are properly formatted in accordance with MLA formatting style. Cynthia Ozick was a second born in her family and her father owned a drugstore where Cynthia would assist him in delivering prescriptions. She hailed from a family that greatly valued education and that is why she ended following the path she took, wring novels, poems and plays. Her father was a great Jewish scholar while her uncle was a renown Hebrew poet whose work was widely read. It is her uncle who for the first time introduced her in the field of literature thereby laying the foundation of her future career. (Rothstein) She attended school at a time when anti-Semitism was on the highest degree. She first experienced it while she was schooling at Pelham Bay section where she would receive anti Semitic slurs and attacks especially when Christmas carols were sung in class for she would not sing along as it was her principle. (Jiffynotes. com) She never gave up with school life instead she read books of her older brothers and would get others from a mobile library that passed by their drugstore. Her life took a new dimension when she joined high school at Hunter College where she found the situation being different from that in primary school life in that her education excellence was respected and greatly appreciated something that paved way for her to pursue higher education in 1949 at New York University and later to join Ohio State University for her Master’s program. (Fallon, E. 320-22) Generally speaking, though her life was good at home it was not the same in public. It was in accordance with Jewish culture that young children in America be taken for religious instructions and Cynthia Ozick was no exception. She experienced her first childhood pain at the age of five and half when her grandmother took her for those classes at Yiddish only to be disappointed by the Rabbi who refused to accept the girl arguing that there was no need to educate females. â€Å"Take her home, a girl does not have to study’ (Lowin) Rabbi had no idea whom she was sending away because the girl was bright. Though she was sent away, her grandmother never gave up in fact she took her again the next morning and she was accepted. Rabbi later discovered that the girl was a quick learner and through Rabbi Cynthia came to learn Yiddish knowledge. The experience of her being sent away from school by Rabbi who believed that girls were dispensable to be educated motivated Cynthia in one way or the other. She says that her feminism cropped up due to this treatment. (Lowin J.) Another thing that motivated her to write novels was the memories of how she was treated at school in Bronx. Though the girl was intelligent there are other things that made her feel inadequate, ‘While Ozick describes the Pelham Bay section of the Bronx as a lovely place she found it ‘brutally’ difficult to be a Jew there she remembers having stones thrown at her and being called a Christ-killer as she ran past the two churches in her neighborhood† (Lowin J). she recalls how she was treated so many years down the line something she confirms in her novel, The Cannibal Galaxy which where she describes her life in school that she was suffering like a little worm in school perhaps because she was an immigrant child left under the hands of a teacher who cared less about her life. According to Fallon (323), though Cynthia would not relate well with other children at school there was another option and a better one, books. After school she would burry her head in books that she got from a mobile library that passed by their drugstore once in a week. She says that the mobile librarians would take their cup of coffee at Park View Pharmacy after they were through with their work and she would pick two big books and magazines which transferred her completely to another world, a world different from what she experienced in school, a world of books where no one would interfere with her life. It could be said that harassment she experienced at school was a blessing in disguise because it made her to study more thereby increasing her level of intelligence. She was motivated to spend more of her time reading as she could not relate well with other students who would even criticize and throw stones at her while passing by them. (Fallon 324) The books she received from the traveling library magically transformed her life from that of a doltish schoolgirl to a reader and a prominent writer. She started by going through fairly tails and ended up being a renown novelist. The other motivational force came from her uncle Abraham Regelson, a poet who was admired for his outstanding composing and writing skills. She says that Regelson paved a way for her to follow what she refers to as a strange career. She says, â€Å"It seemed quite natural to belong to the secular Id of literature† (Lowin). She attributed her career choice to her gender arguing that if she was born a boy may be she would have pursue something else instead of what she did. She felt more motivated when she joined high school at Hunter College, Manhattan. The school atmosphere was different from that of the primary school. Here it was academic excellence that made one to be recognized and for the simple reason that she was extremely bright, she felt like she was part of the big elite group. She clearly describes those feelings in her short story book â€Å"An Education. † After she successfully completed her high school education, she proceeded to the University of New York for her BA degree and after that joined Ohio state university for her Masters degree where she wrote her thesis ‘Parable in the Later Novels of Henry James’. In her peace of work entitled, According to Lowin, the lesson of the Master Cynthia Ozick explains how she was influenced by the work of Henry James such that she became a worshipper of literature. She says, â€Å"A worshipper who had to choose between human entanglement, real life and exclusive devotion to art, chooses art. She chose art over life, she says to her eternal regret† (Lowin). Her definition in work of art was confirmed when she directed all her efforts to what she referred to as ‘High Art’ and she embarked on writing philosophical novels such as Mercy, Pity, Peace and Love (MPPL). After that she stopped writing novels and committing herself to other pieces of work like writing Jewish literature. She also got culturally transformed and became what could be termed as Jewish autodidact (Rothstein, M. ). Later, she would further be influenced by the work of Heinrich Graetz – History of the Jews and thereby she took another dimension as far as writing was concerned. She started writing more about Jews and came to be referred to as a Jewish writer. She wrote many poems with Jewish themes and also published another piece of work entitled the Pagan Rabbi in 1966 which made her very popular as it was widely read. It is from this time that her character in the field of writing started to shine internationally. She won several awards and her stories were chosen as the best in the yearly American Short Stories. She also won the Faultner Award and the National Book Award plus other dozen grants and awards that were only coveted by many not mentioning the several honorary degrees she was warded by various universities. (Associated Press) Though she was not a direct victim of the Jewish Holocaust, she would recall how Jews were killed by deadly gas by the ruthless Nazis and particularly in Germany. These memories have also become another motivating force behind her career as a Jewish writer because she has spent a great deal of time and energy writing about what was happening during that time. In conclusion it can be said that Cynthia Ozick’s career was to a large extent shaped by anti-Semitism attacks she met at school. The fact that other students were isolating her and openly criticized opened another door for her. She found solace in books which she received from a mobile library that passed by their drug store. Again having come from a family with people who valued education, she got motivated to study harder than others. Later was later influenced by the work of Regelson and Heinrich Graetz. Again the memories of how the Jews were treated during the First World War reawakened her conscience something that made her to switch to a Jewish leader. Works Cited: Associated Press. Author Cynthia Ozick wins to lifetime achievement awards. Times Record News. April 24, 2008. Accessed at http://www. timesrecordnews. com/news/2008/apr/24/author-cynthia-ozick-wins-2- lifetime-achievement-a/? printer=1/ Lowin, J. Cynthia Ozick. Jewish Virtual Library. 1928. Available at http://www. jewishvirtuallibrary. org/jsource/biography/Ozick. html Fallon, E. A Readers Companion to the Short Story in English Society for the Study of the Short Story. Greenwood Publishing Group, 2001 Jiffy notes . com. Cynthia Ozick. Thomson Gale, 2006. Available at http://www. jiffynotes. com/a_study_guides/book_notes/ssfs_0000_0022_0/ssfs_0 000_0022_0_00022. html Rothstein, M. Cynthia Ozicks Rabbinical Approach to Literature. New York Times. March 25, 1987. Available at http://query. nytimes. com/gst/fullpage. html? res=9B0DE5D91330F936A15750C0 A961948260sec=spon=pagewanted=all

Utilisation of Wind Energy for High Rise Building Power

Utilisation of Wind Energy for High Rise Building Power Introduction The price of conventional energy is on the rise, due to the ever-widening gap between demands and supply. The main reason for such shortages is the depletion in natural resources, such as coal, which is the main fuel used for electrical energy generation. Since these fuels are made up of carbon compounds, burning them has rapidly increased the amount of carbon dioxide in the atmosphere over the last 100 years. This has brought about a chain reaction of hazards such as global warming, climate change, destruction of ecosystems, etc with predictions for adverse outcomes in the future. In response to this threat and to initiate an end to such processes, the UN agreed the Kyoto Protocol in Japan in 1997. This requires industrialised nations to reduce greenhouse gas emissions by 5% of 1990 levels by 2008-2012. The UK has agreed to meet this target and furthered its promise by setting a goal of 50% reduction in carbon emissions by 2050[ ]. Part of its government energy policy is to increase the contribution of electricity supplied by renewable energy to 10% by 2010 (Blackmore P, 2004). A similar promise has been undertaken by many world nations, which has led to a plethora of new and innovative methods for power generation. Renewable is the key to climate friendly forms of energy, due to the absence of emissions detrimental to the environment (Stiebler M, 2008). It includes energy derived from sunlight, wind, wave, tides and geothermal heat. Out of the afore mentioned resources, geothermal heat is restricted to only limited locations on the globe while wave and tidal power is still in its research stage. Thus sunlight and wind are the key elements that can be tapped for energy generation. However, on comparison between the two systems, wind energy systems are more advantageous both in availability of resources and cost of generation. This report mainly focuses on wind energy, with a keen interest on harvesting it for ventilation and power generation purposes in high-rise buildings. Plan forms that aid this purpose will be studied using Computational Fluid Dynamics to understand the flow of wind in and around a thirty-storey structure and the building configuration well suited for natural ventilation and wind turbine integration would be identified at the end of the test. To obtain a complete picture of wind flow patterns and to closely mimic real life situations, the wind will be simulated from different directions at different wind speeds. Wind energy Wind is the term used for air in motion and is usually applied to the natural horizontal motion of the atmosphere (Taranath Bungale S, 2005). It is brought about by the movement of atmospheric air masses that occur due to variations in atmospheric pressure, which in turn are the results of differences in the solar heating of different parts of the earth’s surface (Boyle G, 2004). At a macro level wind profile differs from place to place depending on geographic location and climatic conditions while in a microstate the immediate physical environment of a particular place modifies the nature of the winds. For example, the velocity of the wind recorded in the countryside which has acres of unobstructed grassland would be greater than that recorded in a city dominated by skyscrapers. Hence to obtain a clear idea of the wind characteristic corresponding to a particular area the wind rose is utilized. They are based on metrological observations and depict the varying wind speeds experienced by a site at different times of the year together with the frequency of different wind directions [ ]. It is the first tool consulted to judge the wind resources of a site and its ability to support power generation. The winds have been tapped from ancient times by means of ship sails, windmills, wind catchers, etc. The history of windmills goes back more than 2000 years (Stiebler M, 2008) when they were predominantly used for grinding grain and pumping water. However, the breakthrough occurred when Charles.F.Brush erected the first automatically operating wind turbine at Ohio in 1888 [ ]. It was fabricated using wood and had a rotor diameter of 17m with 144 blades. The system recorded very low efficiency and was mainly used to charge batteries. The reason behind the poor efficiency was due to the large number of blades, which was later discovered by Poul la Cour who introduced fewer blades into his wind turbine. Though such developments were achieved at an early stage in innovation, it was not until 1980 that the prominent application of renewable energies was sought after (Boyle G, 2004). Wind energy is the harnessing of the kinetic energy prevalent in moving air masses. This kinetic energy for any particular mass of moving air (Boyle G, 2004) is given by the formula: K.E = 0.5mV ² where, m – mass of the air (kg) and V – wind velocity (m/s). However this mass of moving air per second is: m = air density x volume of air flowing per second m = air density x area x velocity   Thus, m = rAV where, r – density of air at sea level = 1.2256 kg/m ³ and A – area covered by the flowing air (m ²) Substituting this value of m in the former equation, K.E. = 0.5rAV ³ (J/s) But energy per unit of time is power and hence the above equation is the power available from the wind. It is also evident that the power is directly proportional to thrice the wind velocity. In other words even a marginal increase in wind speed would yield three folds of the nominal power. This is the critical fact based on which the whole energy process is evolved. However not all of this power can be exhausted since it would lead to nil outflow through the wind turbine, that is no flow of air behind the rotor. This would lead to no flow of air over the turbine causing total failure of the system. According to Albert Betz the maximum amount of power that can be harnessed from the wind is 59.3%. This is often referred to as the Betz limit and has been proven by modern experiments. Some of the advantages of wind energy include: It is based on a non-exhaustive resource and hence can be harnessed for generations. It is a clean and eco friendly way of producing energy. In its working lifetime, the wind turbine produces eighty times the amount of energy that goes into its manufacturing and thus has diminishable net impact on the environment. It does not require any additional resources such as water supply unlike conventional power generation. It can boost the economy of the region (wind farms). Wind turbines: Wind turbines are the modern day adaptations of the yesteryear windmills but unlike their counterparts they are mainly used for power generation. These new age systems come in different shapes and have various configurations, the well established of them all are the Horizontal axis wind turbine and the Vertical axis wind turbine. Write a brief about horizontal wind turbines and vertical wind turbines. BUilding integrated Wind Turbines (BUWT): Building integrated wind turbines are associated with buildings designed and shaped with wind energy in mind (Stankovic S et al, 2009). They are relatively a new way of harnessing energy that is gaining popularity at a quick pace. Small scale wind turbines on house roofs and retrofitting also fall under this category. The design of BUWTs is a complicated affair and involves the careful consideration of various factors. Since turbines are fixed into the building’s fabric its impact on the environment, building’s response and needs of its owners and occupants need to be weighed equally. Also numerous design decisions such as planning, structure, services, construction and maintenance depend on this single process (Stankovic S et al, 2009). With the increase in the scale of the proposal the importance of these factors increases simultaneously. The proposal generally spans from the number, scale, type and location of the turbines together with its annual energy yield and design life. A good BUWT based building should be a wholesome design that does not prejudice the buildings efficient functioning for energy generation. Generic options for BUWTs: Stankovic S et al (2009) explains that the wind turbines can be fixed on to a building in enumerable ways. Each method can accomplish a different level of power depending on the type of turbine used and the form of the building it is mounted upon. On top of a square/ rectangular building: This configuration is on the principle that the wind velocity increases with height and hence the amount of energy generated would be of a higher order (10% increase with wind acceleration). An added advantage is that the turbine would experience relatively little turbulence. But access to the turbine for maintenance and decommissioning works may be difficult. If mounted on tall buildings the turbines may threaten the visual quality of the skyline. On top of a rounded building: This case is very similar to the previous configuration except that with the use of rounded faà §ade the mean tower height can be considerably diminished. Also the rounded profile influences the local acceleration (15% increase in energy). The low tower height favors easy access to the turbine but leads to blade flicker and noise issues. Concentrator on top of a rounded building: This case is well suited to areas with bi-directional winds (20% energy increase over a free standing equivalent due to local acceleration). Vertical axis wind turbines are better suited for this feature while Horizontal axis wind turbines need to be suitably altered to achieve the same status. The building spaces that act as concentrators may be inhabited with suitable acoustical treatment. This case also encounters the same drawbacks as listed in the previous case. Square concentrator within a building faà §ade: As before, this configuration takes advantage of the higher quality winds at higher altitudes and local acceleration thereby achieving 25% increase in energy and 40% increase for bi-directional winds. This option is best suited for buildings with narrower profiles. There may be a loss in the saleable area of the building but the aperture can be converted into an exclusive feature such as a sky garden. The opening also relieves the wind loading on the building’s facade leading to simpler structural solutions. Vertical axis wind turbine is the only choice for integration due to its square swept area. Circular concentrator within a building faà §ade: This is very similar to the square concentrator except the opening is accustomed to hold pitch controlled horizontal axis wind turbines with fixed yaw. Also, a 35% increase for uniform wind and 50% increase in energy for bi-directional winds are achievable in this method. But on the down side, this technique is more expensive due to the cylindrical shroud. On the side of a building: In this technique, an increase in 80-90% in energy than the freestanding equivalents is achievable only if the building form is optimized to the local wind character. Only reliable vertical axis wind turbines can be used for power generation due to access issues. For higher swept area, more number of turbines should be used. Between multiple building forms: This type of an option opens out many doors for a range of architectural forms. Unlike the previous cases, the buildings orientation, form, shape and spacing play key roles in the performance of the turbines. Vertical axis wind turbines are better suited for this purpose. Guidelines for BUWT’s: The following are some guidelines outlined by Stankovic S et al (2009) for incorporating wind turbines into a structure: BUWTs should be tailored to the specific site for good results. Adequate wind resources should be available on site. If however if the site is under resourced steps are to be adopted to deliberately elevate the quality of the wind through the buildings form or turbine. The impact of its surroundings should also be considered before commissioning such a project. The dominating wind direction and its intensity should be observed from meteorological data. This would help in determining the form and orientation of the building together with finalizing the position of the wind turbine to make the most out of the available resource. Environmental impact assessment corresponding to the site should be carried out to foresee the adverse effects the turbines may create. Acoustic isolation may be sought for in some areas within the building if it lies at close proximity to the rotor. Natural ventilation and day lighting qualities of the building may be challenged and forced to settle for artificial means. The type and position of openings, external shading devices, smoke extracts etc should be handled with appropriate care to avoid draught winds. Access to the wind turbines for maintenance and decommissioning must be provided suitably. The aesthetic quality of the mounted turbines must harmonize with its surroundings and should not over power the pedestrians at ground level. To this end well suited screening devices such as canopies, screens and landscape may be utilized as per the necessity. The overall success of BUWT project depends on its ability to deliver the expected power. Inability to comply with this effect would result in the failure of its intended purpose from both an environmental and design point of view. Thus the electricity demand of the building and the level to which this would be met with should be estimated prior to turbine design to secure maximum benefits. Wind flow prediction and energy yields: For any project to be successful, Wind flow and building design (Taranath Bungale S, 2005) When the air moves in a vertical direction it is referred to as a current. These currents play a major role in meteorology whereas the gradual decrease in wind speed and high turbulence of the horizontal motion of air, at the ground level, are vital in building engineering. In urban areas, this zone of turbulence extends to a height of approximately one quarter of a mile aboveground and is called the surface boundary layer. Above this layer, the horizontal airflow is no longer influenced by the ground effect. The wind speed at this height is known as the gradient wind speed, and it is precisely in this boundary layer where most human activity is conducted. Characteristics of wind: The flow of wind is complex because many flow situations arise from the interaction of wind with structures. A few characteristics of wind include: Variation of wind velocity with height: The viscosity of air reduces its velocity adjacent to the earth’s surface to almost zero. A retarding effect occurs in the wind layers near the ground, and these layers in turn successively slow the outer layers. The slowing down is reduced at each layer as the height increases, and eventually becomes negligibly small. The height at which velocity ceases to increase is called the gradient height, and the corresponding velocity, the gradient velocity. At heights of approximately 366m aboveground, the wind speed is virtually unaffected by surface friction, and its movement is solely dependant on prevailing seasonal and local wind effects the height through which the wind speed is affected by topography is called the atmospheric boundary layer. Wind turbulence: Motion of wind is turbulent and it occurs in wind flow because air has a very low viscosity-about one-sixteenth that of water. Any movement of air at speeds greater than 0.9 to 1.3 m/s is turbulent, causing air particles to move randomly in all directions. Vortex shedding: In general, wind buffering against a bluff body such as a rectangular building gets diverted in three mutually perpendicular directions. However, only the longitudinal winds and the transverse winds or crosswinds are considered in civil engineering. When a free flowing mass of air encounters a building along its path, the originally parallel upwind streamlines are displaced on either side of the building. This results in spiral vortices being shed periodically from the sides into the downstream flow of the wind, called the wake. At relatively low wind speeds the vortices are shed, that is, break away from the surface of the building and an impulse is applied in the transverse direction. Distribution of pressures and suctions: When air flows around the edges of a structure, the resulting pressures at the corners are much in excess of the pressures on the center of elevation. This has been evident by the damages caused to corner windows, eave and ridge tiles, etc in windstorms. Wind tunnel studies conducted on scale models of buildings indicate that three distinct pressure areas develop around the building. They are: Positive pressure zone on the upstream face (Region 1) Negative pressure zone at the upstream corners (Region 2) Negative pressure zone on the downstream face (Region 3) The highest negative pressures are created in the upstream corners designated as Region 2. Wind pressures on a buildings surface are not constant, but fluctuate continuously. The positive pressure on the upstream or the windward face fluctuates more than the negative pressure on the downstream or the leeward face. The negative pressure region remains relatively steady as compared to the positive pressure zone. The fluctuation of pressure is random and varies from point to point on the building surface. Nearby buildings can have a significant influence on wind forces. If they are the same height as the structure being considered then they will mostly provide shelter, although local wind loads can be increased in some situations. Where surrounding buildings are significantly taller they will often generate increased wind loading (negative shelter) on nearby lower structures. Shelter can result from either from the general built-environment upwind of the site or from the direct shielding from specific individual upwind buildings (Blackmore P, 2004). Natural ventilation The three natural ventilation airflow paths in buildings are (Pennycook, 2009): Cross ventilation Single-sided ventilation Passive stack ventilation Advantages of cross ventilation: Greater rates of ventilation can be achieved under amicable weather conditions. Can be utilized for deep-plan spaces with operable windows on the external wall. Incumbents have control over ventilation. Relatively cost free. Can be incorporated with thermal masses. However, it has certain limitations such as: Internal space layout must be hindrance free for easy, clear flow of air. Internal partitions must be within 1.2m height and tall cupboards must be placed alongside the windows. Natural ventilation can occur only under the presence of suitable winds. Poor planning and positioning of windows may cause disruptive draughts and gusts. Winter ventilation is problematic. Unsuitable for buildings located in noisy and pollution prone environments. The requirements of fresh air supply are governed by the type of occupancy, number and activity of the occupants and by the nature of any processes carried out in the space (Koenigsberger et al, 2001). When natural ventilation is stipulated for good indoor air quality, the amount and nature of the dominant pollutant source in the space should be identified. Based on this data the ventilation rate for the space can be calculated such that the pollution level does not cross a preset specific mark. Generally the concentration of the pollutants decreases with the increase in airflow rate (Figure –1). However, in terms of thermal comfort especially during winter the heating requirement of the building will increase with the ventilation rate. This demand varies with time, wind characteristics of the place, opening and closing of windows and doors by its occupants and the thermal state of the building. In summer, cooling is ideal for both the building and its occupants to prevent internal heat gains. By directing the high velocity wind around the human body the evaporative rate at the skins surface can be increased thereby achieving a cooling sensation. The recommended upper limit of indoor air movement is 0.8 m/sec, which permits the inhabitants to occupy a space about 2 °C warmer and 60% relative humidity with optimum comfort. The traditional way to cool buildings is to provide large openings along the exterior wall with the principle that higher the ventilation rate greater the loss of heat to the external environment. But such an arrangement would work only when the outdoor te mperature is in the range of comfort zone. When controlled indoor environments are desired especially during the occupancy period’s night ventilation is recommended. In this technique the building is cooled at night so that it can absorb the heat generated during the day (Allard F, 1998). Based on wind tunnel experimental observations, the factors that affect the indoor airflow are: Orientation: External features: Cross-ventilation: Position of openings: Size of openings: Control of openings: Literature review The following are studies that have been made of different aspects of wind using Computational Fluid dynamics. CFD evaluation of wind speed conditions in passages between parallel buildings: This analysis undertaken by Blocken B et al (2007) mainly focuses on the wind speed conditions in passages between parallel buildings in combination with the accuracy of the commercial CFD code Fluent 6.1.22 when the wall-function roughness modifications are applied to them. The Venturi effect is also studied to determine the amount of increase in wind speed in the passage due to the decrease in flow section. The results obtained were compared with various previously proven experiments carried out by experts in the field. As the title indicated the case undertaken involves a pair of rectangular buildings measuring 40m x 20m x 20m, placed adjacent to each other and separated by a narrow passage. The width of the passage is widened (for example, 2, 4, 6, 8, 10, 15, 20, 30, 40, 60, 80, 100 m) with every case to clearly understand the Venturi effect. The dimension of the computational domain is 20.5x14x18m3; the whole setup is placed at a distance of 5m from the inlet and simulated with a wind speed of 6.8m/sec based on initial results. The results recorded at the end of the simulation process are discussed as follows. They are based on the amplification factor, which is defined as the ratio of the mean wind speed at a certain location to the mean wind speed at the same location without the buildings present. As such it is a direct indication of the effect of the buildings on the wind speed (Blocken B et al, 2007). Pedestrian level wind profile: In context to this research, for narrow passages (example w=2m) this amplification factor occurs maximum at the centerline immediately behind the entrance. When the distance between the buildings are slightly increased (example w=10m), the flow streams deflecting off the inner edges of the buildings combine into a large jet stream and records an increase in the amplification factor. However this property is lost when the width of the passage is of a high order (example w=30m). Overall wind profile: To understand the overall wind profile, six vertical lines were identified along the passage’s center plane for the case of w=6m. The lines depicted the fact that there was an increase in the wind speed at the ground level due to the downdraft of the wind along the front faà §ade of the building and a decrease in wind speed at the end of the passage due to the exit of flow from the passage. Also for these cases, there was no significant increase in the wind speed with the increase in height. Flow rates at different points in the passage: To evaluate the Venturi-effect three fluxes were defined, one along the vertical plane, another along the horizontal plan and the final being similar to the former one but in the absence of the buildings. When the flow rate was calculated for narrow passages, it stated an increase in wind speed by only 8% due to the Venturi effect. However for larger widths the flow rate was lower than the free-field flux. This shows that the wind has a tendency to flow over and around the building rather than be forced through the passage as previously believed. Thus there is a lack of strong Venturi effect and the flow in the passage can be attributed as the channeling effect for these cases. The research also concluded that there were discrepancies in the CFD results due to the use of the roughness factor and advised future users to simulate an empty field before positioning the buildings to clearly identify the difference in results. Further research into the Venturi effect was also implied. Computational analysis of wind driven natural ventilation in buildings: Evola G and Popov V (2006) research focuses on the application of three-dimensional Reynolds Averaged Navier-Strokes (RANS) modeling on wind driven natural ventilation with specific detail to the pressure distribution and flow pattern within the building. The various cases would be simulated with the standard k-e model and the Renormalization Group theory (RNG). Within the framework of natural ventilation both single sided ventilation and cross ventilation would be studied and the results obtained using CFD will be compared with LES models and empirical methods for its reliability.  Ã‚  Ã‚   The building undertaken consists of a 250mm x 250mm x 250mm cube punctured with a centrally located 84mm x 125 mm opening on the wind ward side (Case 1). In Case 2 the door like opening is placed on the leeward side and in Case 3 both the openings are retained to test the cross ventilation principle. On comparison between the CFD results obtained for Case 1 and 2, Case 2 portrays a better flow pattern especially at the mouth of the opening. This leads to a better ventilation rate than Case 1 though in contrast to the theoretical data that good ventilation rate and flow patterns are achievable only when the opening faces the incoming winds. To establish the phenomenon further experimentation into the field was suggested. Between Cases 1, 2 and 3, cross ventilation clearly stands out as the best option of them all, both in terms of velocity and distribution. Also the study concluded that the measured RNG results matched approximately to the theoretical results of Cases 1 and 2. But a significant amount of deviation was observed in Case 3. The RNG model was only slightly intense than the k-e model generally used. The research also concluded that there were discrepancies in the CFD results due to the use of the roughness factor and advised future users to simulate an empty field before positioning the buildings to clearly identify the difference in results. Further research into the Venturi effect was also implied. CFD modeling of unsteady cross-ventilation flows using LES: This research undertaken by Cheng-Hu Hu et al (2008) employs the LES method to investigate the fluctuating ventilation flow rate induced by the wind for a cross-ventilated building. The results from CFD were compared with those previously acquired from wind tunnel tests.   Ã‚   The building proposed for the study consists of a rectangular box with two openings of equal size located opposite to each other. The wind is simulated from 0 °(Case 1) and 90 °(Case 2) to the building at a rate of 1m/sec, to study the flow pattern in and around it. When the air approaches the building the ventilation rate is unsteady at the mouth of the openings due to turbulence and in the flow separation layer due to shear. In Case 1 the wind is accelerated through the opening and directed downwards inside the building. This phenomenon brings about a circulation of the internal air before guiding the wind upwards and out through the window on the leeward side of the building. The air exchange occurs due to the mean flows through the opening. In Case 2 where the wind is parallel to the windows, the air moves in and exits rapidly causing fluctuating flows thereby leading to air exchange. In this case turbulence prone areas are formed at the rear of the building. When these results were compared with the wind tunnel data, Case 1 portrayed similarities while Case 2 had major deviations. Further study was proposed for understanding the reason behind such deviations. Case studies The Bahrain world trade centre was the world’s first building to ‘aesthetically incorporate commercial wind turbines into the fabric of the building’ [ ]. The complex consists of a three-storied sculpted podium and basement from where the 240m high towers rise up into the sky. The two towers comprise of 51 floors each and are connected by means of three, 31.5m span bridges at 60m, 96m and 132m levels [ ]. They are oval in section for aerodynamic reasons and follow a shallow V-shape in plan for adequate blade clearance. Sitting on each of this 70 ton spandrel is an 11-ton nacelle to which the industry approved horizontal axis wind turbines are fixed by special means. The turbine has a rotor diameter of 29m and is stall controlled with centrifugally activated feathering tips for air brakes (Killa S Smith Richard F, 2008). The turbines are oriented facing the Arabian Gulf intercepting the path of the dominant winds. The decision to harness the prevailing wind was thought of from the initial stage drawing inspiration from ‘the regional wind towers and the vast sails of the traditional Arabian Dhow which utilise the wind to drive them forward’. Numerous Computational fluid dynamics models and wind tunnel tests were carried out to determine the final building form. The result was a skyward tapering, elliptical structure, carved out by the wind that functions as aerofoil sections (Wood A, 2008). The shape and spatial relationship of the towers aid in adhering the wind in a â€Å"S’ flow whereby the center of the wind stream remains nearly perpendicular to the turbine within a 45 ° wind azimuth, either side of the central axis (Killa S Smith Richard F, 2008). This increases the turbine efficiency, number of working hours and minimizes the stress on the blade caused by yawing [ ]. Furthermore, the two towers were placed such that they create a ‘V’ shaped space in between them, as well as a negative pressure behind the blocks, thus creating an opportunity for the Venturi effect to accelerate wind velocity onto the turbines (Binder G, 2006) by as much as 30% more than the source wind (Killa S Smith Richard F, 2008). The tapering profile combined with the increased onshore wind velocity at higher altitudes creates a near equal regime of wind speed on each of the three turbines, irrespective of its location, allowing them to rotate at the same speed and generate approximately the same amount of energy (Wood A, 2008). Table 1: Annual energy output Utilisation of Wind Energy for High Rise Building Power Utilisation of Wind Energy for High Rise Building Power Introduction The price of conventional energy is on the rise, due to the ever-widening gap between demands and supply. The main reason for such shortages is the depletion in natural resources, such as coal, which is the main fuel used for electrical energy generation. Since these fuels are made up of carbon compounds, burning them has rapidly increased the amount of carbon dioxide in the atmosphere over the last 100 years. This has brought about a chain reaction of hazards such as global warming, climate change, destruction of ecosystems, etc with predictions for adverse outcomes in the future. In response to this threat and to initiate an end to such processes, the UN agreed the Kyoto Protocol in Japan in 1997. This requires industrialised nations to reduce greenhouse gas emissions by 5% of 1990 levels by 2008-2012. The UK has agreed to meet this target and furthered its promise by setting a goal of 50% reduction in carbon emissions by 2050[ ]. Part of its government energy policy is to increase the contribution of electricity supplied by renewable energy to 10% by 2010 (Blackmore P, 2004). A similar promise has been undertaken by many world nations, which has led to a plethora of new and innovative methods for power generation. Renewable is the key to climate friendly forms of energy, due to the absence of emissions detrimental to the environment (Stiebler M, 2008). It includes energy derived from sunlight, wind, wave, tides and geothermal heat. Out of the afore mentioned resources, geothermal heat is restricted to only limited locations on the globe while wave and tidal power is still in its research stage. Thus sunlight and wind are the key elements that can be tapped for energy generation. However, on comparison between the two systems, wind energy systems are more advantageous both in availability of resources and cost of generation. This report mainly focuses on wind energy, with a keen interest on harvesting it for ventilation and power generation purposes in high-rise buildings. Plan forms that aid this purpose will be studied using Computational Fluid Dynamics to understand the flow of wind in and around a thirty-storey structure and the building configuration well suited for natural ventilation and wind turbine integration would be identified at the end of the test. To obtain a complete picture of wind flow patterns and to closely mimic real life situations, the wind will be simulated from different directions at different wind speeds. Wind energy Wind is the term used for air in motion and is usually applied to the natural horizontal motion of the atmosphere (Taranath Bungale S, 2005). It is brought about by the movement of atmospheric air masses that occur due to variations in atmospheric pressure, which in turn are the results of differences in the solar heating of different parts of the earth’s surface (Boyle G, 2004). At a macro level wind profile differs from place to place depending on geographic location and climatic conditions while in a microstate the immediate physical environment of a particular place modifies the nature of the winds. For example, the velocity of the wind recorded in the countryside which has acres of unobstructed grassland would be greater than that recorded in a city dominated by skyscrapers. Hence to obtain a clear idea of the wind characteristic corresponding to a particular area the wind rose is utilized. They are based on metrological observations and depict the varying wind speeds experienced by a site at different times of the year together with the frequency of different wind directions [ ]. It is the first tool consulted to judge the wind resources of a site and its ability to support power generation. The winds have been tapped from ancient times by means of ship sails, windmills, wind catchers, etc. The history of windmills goes back more than 2000 years (Stiebler M, 2008) when they were predominantly used for grinding grain and pumping water. However, the breakthrough occurred when Charles.F.Brush erected the first automatically operating wind turbine at Ohio in 1888 [ ]. It was fabricated using wood and had a rotor diameter of 17m with 144 blades. The system recorded very low efficiency and was mainly used to charge batteries. The reason behind the poor efficiency was due to the large number of blades, which was later discovered by Poul la Cour who introduced fewer blades into his wind turbine. Though such developments were achieved at an early stage in innovation, it was not until 1980 that the prominent application of renewable energies was sought after (Boyle G, 2004). Wind energy is the harnessing of the kinetic energy prevalent in moving air masses. This kinetic energy for any particular mass of moving air (Boyle G, 2004) is given by the formula: K.E = 0.5mV ² where, m – mass of the air (kg) and V – wind velocity (m/s). However this mass of moving air per second is: m = air density x volume of air flowing per second m = air density x area x velocity   Thus, m = rAV where, r – density of air at sea level = 1.2256 kg/m ³ and A – area covered by the flowing air (m ²) Substituting this value of m in the former equation, K.E. = 0.5rAV ³ (J/s) But energy per unit of time is power and hence the above equation is the power available from the wind. It is also evident that the power is directly proportional to thrice the wind velocity. In other words even a marginal increase in wind speed would yield three folds of the nominal power. This is the critical fact based on which the whole energy process is evolved. However not all of this power can be exhausted since it would lead to nil outflow through the wind turbine, that is no flow of air behind the rotor. This would lead to no flow of air over the turbine causing total failure of the system. According to Albert Betz the maximum amount of power that can be harnessed from the wind is 59.3%. This is often referred to as the Betz limit and has been proven by modern experiments. Some of the advantages of wind energy include: It is based on a non-exhaustive resource and hence can be harnessed for generations. It is a clean and eco friendly way of producing energy. In its working lifetime, the wind turbine produces eighty times the amount of energy that goes into its manufacturing and thus has diminishable net impact on the environment. It does not require any additional resources such as water supply unlike conventional power generation. It can boost the economy of the region (wind farms). Wind turbines: Wind turbines are the modern day adaptations of the yesteryear windmills but unlike their counterparts they are mainly used for power generation. These new age systems come in different shapes and have various configurations, the well established of them all are the Horizontal axis wind turbine and the Vertical axis wind turbine. Write a brief about horizontal wind turbines and vertical wind turbines. BUilding integrated Wind Turbines (BUWT): Building integrated wind turbines are associated with buildings designed and shaped with wind energy in mind (Stankovic S et al, 2009). They are relatively a new way of harnessing energy that is gaining popularity at a quick pace. Small scale wind turbines on house roofs and retrofitting also fall under this category. The design of BUWTs is a complicated affair and involves the careful consideration of various factors. Since turbines are fixed into the building’s fabric its impact on the environment, building’s response and needs of its owners and occupants need to be weighed equally. Also numerous design decisions such as planning, structure, services, construction and maintenance depend on this single process (Stankovic S et al, 2009). With the increase in the scale of the proposal the importance of these factors increases simultaneously. The proposal generally spans from the number, scale, type and location of the turbines together with its annual energy yield and design life. A good BUWT based building should be a wholesome design that does not prejudice the buildings efficient functioning for energy generation. Generic options for BUWTs: Stankovic S et al (2009) explains that the wind turbines can be fixed on to a building in enumerable ways. Each method can accomplish a different level of power depending on the type of turbine used and the form of the building it is mounted upon. On top of a square/ rectangular building: This configuration is on the principle that the wind velocity increases with height and hence the amount of energy generated would be of a higher order (10% increase with wind acceleration). An added advantage is that the turbine would experience relatively little turbulence. But access to the turbine for maintenance and decommissioning works may be difficult. If mounted on tall buildings the turbines may threaten the visual quality of the skyline. On top of a rounded building: This case is very similar to the previous configuration except that with the use of rounded faà §ade the mean tower height can be considerably diminished. Also the rounded profile influences the local acceleration (15% increase in energy). The low tower height favors easy access to the turbine but leads to blade flicker and noise issues. Concentrator on top of a rounded building: This case is well suited to areas with bi-directional winds (20% energy increase over a free standing equivalent due to local acceleration). Vertical axis wind turbines are better suited for this feature while Horizontal axis wind turbines need to be suitably altered to achieve the same status. The building spaces that act as concentrators may be inhabited with suitable acoustical treatment. This case also encounters the same drawbacks as listed in the previous case. Square concentrator within a building faà §ade: As before, this configuration takes advantage of the higher quality winds at higher altitudes and local acceleration thereby achieving 25% increase in energy and 40% increase for bi-directional winds. This option is best suited for buildings with narrower profiles. There may be a loss in the saleable area of the building but the aperture can be converted into an exclusive feature such as a sky garden. The opening also relieves the wind loading on the building’s facade leading to simpler structural solutions. Vertical axis wind turbine is the only choice for integration due to its square swept area. Circular concentrator within a building faà §ade: This is very similar to the square concentrator except the opening is accustomed to hold pitch controlled horizontal axis wind turbines with fixed yaw. Also, a 35% increase for uniform wind and 50% increase in energy for bi-directional winds are achievable in this method. But on the down side, this technique is more expensive due to the cylindrical shroud. On the side of a building: In this technique, an increase in 80-90% in energy than the freestanding equivalents is achievable only if the building form is optimized to the local wind character. Only reliable vertical axis wind turbines can be used for power generation due to access issues. For higher swept area, more number of turbines should be used. Between multiple building forms: This type of an option opens out many doors for a range of architectural forms. Unlike the previous cases, the buildings orientation, form, shape and spacing play key roles in the performance of the turbines. Vertical axis wind turbines are better suited for this purpose. Guidelines for BUWT’s: The following are some guidelines outlined by Stankovic S et al (2009) for incorporating wind turbines into a structure: BUWTs should be tailored to the specific site for good results. Adequate wind resources should be available on site. If however if the site is under resourced steps are to be adopted to deliberately elevate the quality of the wind through the buildings form or turbine. The impact of its surroundings should also be considered before commissioning such a project. The dominating wind direction and its intensity should be observed from meteorological data. This would help in determining the form and orientation of the building together with finalizing the position of the wind turbine to make the most out of the available resource. Environmental impact assessment corresponding to the site should be carried out to foresee the adverse effects the turbines may create. Acoustic isolation may be sought for in some areas within the building if it lies at close proximity to the rotor. Natural ventilation and day lighting qualities of the building may be challenged and forced to settle for artificial means. The type and position of openings, external shading devices, smoke extracts etc should be handled with appropriate care to avoid draught winds. Access to the wind turbines for maintenance and decommissioning must be provided suitably. The aesthetic quality of the mounted turbines must harmonize with its surroundings and should not over power the pedestrians at ground level. To this end well suited screening devices such as canopies, screens and landscape may be utilized as per the necessity. The overall success of BUWT project depends on its ability to deliver the expected power. Inability to comply with this effect would result in the failure of its intended purpose from both an environmental and design point of view. Thus the electricity demand of the building and the level to which this would be met with should be estimated prior to turbine design to secure maximum benefits. Wind flow prediction and energy yields: For any project to be successful, Wind flow and building design (Taranath Bungale S, 2005) When the air moves in a vertical direction it is referred to as a current. These currents play a major role in meteorology whereas the gradual decrease in wind speed and high turbulence of the horizontal motion of air, at the ground level, are vital in building engineering. In urban areas, this zone of turbulence extends to a height of approximately one quarter of a mile aboveground and is called the surface boundary layer. Above this layer, the horizontal airflow is no longer influenced by the ground effect. The wind speed at this height is known as the gradient wind speed, and it is precisely in this boundary layer where most human activity is conducted. Characteristics of wind: The flow of wind is complex because many flow situations arise from the interaction of wind with structures. A few characteristics of wind include: Variation of wind velocity with height: The viscosity of air reduces its velocity adjacent to the earth’s surface to almost zero. A retarding effect occurs in the wind layers near the ground, and these layers in turn successively slow the outer layers. The slowing down is reduced at each layer as the height increases, and eventually becomes negligibly small. The height at which velocity ceases to increase is called the gradient height, and the corresponding velocity, the gradient velocity. At heights of approximately 366m aboveground, the wind speed is virtually unaffected by surface friction, and its movement is solely dependant on prevailing seasonal and local wind effects the height through which the wind speed is affected by topography is called the atmospheric boundary layer. Wind turbulence: Motion of wind is turbulent and it occurs in wind flow because air has a very low viscosity-about one-sixteenth that of water. Any movement of air at speeds greater than 0.9 to 1.3 m/s is turbulent, causing air particles to move randomly in all directions. Vortex shedding: In general, wind buffering against a bluff body such as a rectangular building gets diverted in three mutually perpendicular directions. However, only the longitudinal winds and the transverse winds or crosswinds are considered in civil engineering. When a free flowing mass of air encounters a building along its path, the originally parallel upwind streamlines are displaced on either side of the building. This results in spiral vortices being shed periodically from the sides into the downstream flow of the wind, called the wake. At relatively low wind speeds the vortices are shed, that is, break away from the surface of the building and an impulse is applied in the transverse direction. Distribution of pressures and suctions: When air flows around the edges of a structure, the resulting pressures at the corners are much in excess of the pressures on the center of elevation. This has been evident by the damages caused to corner windows, eave and ridge tiles, etc in windstorms. Wind tunnel studies conducted on scale models of buildings indicate that three distinct pressure areas develop around the building. They are: Positive pressure zone on the upstream face (Region 1) Negative pressure zone at the upstream corners (Region 2) Negative pressure zone on the downstream face (Region 3) The highest negative pressures are created in the upstream corners designated as Region 2. Wind pressures on a buildings surface are not constant, but fluctuate continuously. The positive pressure on the upstream or the windward face fluctuates more than the negative pressure on the downstream or the leeward face. The negative pressure region remains relatively steady as compared to the positive pressure zone. The fluctuation of pressure is random and varies from point to point on the building surface. Nearby buildings can have a significant influence on wind forces. If they are the same height as the structure being considered then they will mostly provide shelter, although local wind loads can be increased in some situations. Where surrounding buildings are significantly taller they will often generate increased wind loading (negative shelter) on nearby lower structures. Shelter can result from either from the general built-environment upwind of the site or from the direct shielding from specific individual upwind buildings (Blackmore P, 2004). Natural ventilation The three natural ventilation airflow paths in buildings are (Pennycook, 2009): Cross ventilation Single-sided ventilation Passive stack ventilation Advantages of cross ventilation: Greater rates of ventilation can be achieved under amicable weather conditions. Can be utilized for deep-plan spaces with operable windows on the external wall. Incumbents have control over ventilation. Relatively cost free. Can be incorporated with thermal masses. However, it has certain limitations such as: Internal space layout must be hindrance free for easy, clear flow of air. Internal partitions must be within 1.2m height and tall cupboards must be placed alongside the windows. Natural ventilation can occur only under the presence of suitable winds. Poor planning and positioning of windows may cause disruptive draughts and gusts. Winter ventilation is problematic. Unsuitable for buildings located in noisy and pollution prone environments. The requirements of fresh air supply are governed by the type of occupancy, number and activity of the occupants and by the nature of any processes carried out in the space (Koenigsberger et al, 2001). When natural ventilation is stipulated for good indoor air quality, the amount and nature of the dominant pollutant source in the space should be identified. Based on this data the ventilation rate for the space can be calculated such that the pollution level does not cross a preset specific mark. Generally the concentration of the pollutants decreases with the increase in airflow rate (Figure –1). However, in terms of thermal comfort especially during winter the heating requirement of the building will increase with the ventilation rate. This demand varies with time, wind characteristics of the place, opening and closing of windows and doors by its occupants and the thermal state of the building. In summer, cooling is ideal for both the building and its occupants to prevent internal heat gains. By directing the high velocity wind around the human body the evaporative rate at the skins surface can be increased thereby achieving a cooling sensation. The recommended upper limit of indoor air movement is 0.8 m/sec, which permits the inhabitants to occupy a space about 2 °C warmer and 60% relative humidity with optimum comfort. The traditional way to cool buildings is to provide large openings along the exterior wall with the principle that higher the ventilation rate greater the loss of heat to the external environment. But such an arrangement would work only when the outdoor te mperature is in the range of comfort zone. When controlled indoor environments are desired especially during the occupancy period’s night ventilation is recommended. In this technique the building is cooled at night so that it can absorb the heat generated during the day (Allard F, 1998). Based on wind tunnel experimental observations, the factors that affect the indoor airflow are: Orientation: External features: Cross-ventilation: Position of openings: Size of openings: Control of openings: Literature review The following are studies that have been made of different aspects of wind using Computational Fluid dynamics. CFD evaluation of wind speed conditions in passages between parallel buildings: This analysis undertaken by Blocken B et al (2007) mainly focuses on the wind speed conditions in passages between parallel buildings in combination with the accuracy of the commercial CFD code Fluent 6.1.22 when the wall-function roughness modifications are applied to them. The Venturi effect is also studied to determine the amount of increase in wind speed in the passage due to the decrease in flow section. The results obtained were compared with various previously proven experiments carried out by experts in the field. As the title indicated the case undertaken involves a pair of rectangular buildings measuring 40m x 20m x 20m, placed adjacent to each other and separated by a narrow passage. The width of the passage is widened (for example, 2, 4, 6, 8, 10, 15, 20, 30, 40, 60, 80, 100 m) with every case to clearly understand the Venturi effect. The dimension of the computational domain is 20.5x14x18m3; the whole setup is placed at a distance of 5m from the inlet and simulated with a wind speed of 6.8m/sec based on initial results. The results recorded at the end of the simulation process are discussed as follows. They are based on the amplification factor, which is defined as the ratio of the mean wind speed at a certain location to the mean wind speed at the same location without the buildings present. As such it is a direct indication of the effect of the buildings on the wind speed (Blocken B et al, 2007). Pedestrian level wind profile: In context to this research, for narrow passages (example w=2m) this amplification factor occurs maximum at the centerline immediately behind the entrance. When the distance between the buildings are slightly increased (example w=10m), the flow streams deflecting off the inner edges of the buildings combine into a large jet stream and records an increase in the amplification factor. However this property is lost when the width of the passage is of a high order (example w=30m). Overall wind profile: To understand the overall wind profile, six vertical lines were identified along the passage’s center plane for the case of w=6m. The lines depicted the fact that there was an increase in the wind speed at the ground level due to the downdraft of the wind along the front faà §ade of the building and a decrease in wind speed at the end of the passage due to the exit of flow from the passage. Also for these cases, there was no significant increase in the wind speed with the increase in height. Flow rates at different points in the passage: To evaluate the Venturi-effect three fluxes were defined, one along the vertical plane, another along the horizontal plan and the final being similar to the former one but in the absence of the buildings. When the flow rate was calculated for narrow passages, it stated an increase in wind speed by only 8% due to the Venturi effect. However for larger widths the flow rate was lower than the free-field flux. This shows that the wind has a tendency to flow over and around the building rather than be forced through the passage as previously believed. Thus there is a lack of strong Venturi effect and the flow in the passage can be attributed as the channeling effect for these cases. The research also concluded that there were discrepancies in the CFD results due to the use of the roughness factor and advised future users to simulate an empty field before positioning the buildings to clearly identify the difference in results. Further research into the Venturi effect was also implied. Computational analysis of wind driven natural ventilation in buildings: Evola G and Popov V (2006) research focuses on the application of three-dimensional Reynolds Averaged Navier-Strokes (RANS) modeling on wind driven natural ventilation with specific detail to the pressure distribution and flow pattern within the building. The various cases would be simulated with the standard k-e model and the Renormalization Group theory (RNG). Within the framework of natural ventilation both single sided ventilation and cross ventilation would be studied and the results obtained using CFD will be compared with LES models and empirical methods for its reliability.  Ã‚  Ã‚   The building undertaken consists of a 250mm x 250mm x 250mm cube punctured with a centrally located 84mm x 125 mm opening on the wind ward side (Case 1). In Case 2 the door like opening is placed on the leeward side and in Case 3 both the openings are retained to test the cross ventilation principle. On comparison between the CFD results obtained for Case 1 and 2, Case 2 portrays a better flow pattern especially at the mouth of the opening. This leads to a better ventilation rate than Case 1 though in contrast to the theoretical data that good ventilation rate and flow patterns are achievable only when the opening faces the incoming winds. To establish the phenomenon further experimentation into the field was suggested. Between Cases 1, 2 and 3, cross ventilation clearly stands out as the best option of them all, both in terms of velocity and distribution. Also the study concluded that the measured RNG results matched approximately to the theoretical results of Cases 1 and 2. But a significant amount of deviation was observed in Case 3. The RNG model was only slightly intense than the k-e model generally used. The research also concluded that there were discrepancies in the CFD results due to the use of the roughness factor and advised future users to simulate an empty field before positioning the buildings to clearly identify the difference in results. Further research into the Venturi effect was also implied. CFD modeling of unsteady cross-ventilation flows using LES: This research undertaken by Cheng-Hu Hu et al (2008) employs the LES method to investigate the fluctuating ventilation flow rate induced by the wind for a cross-ventilated building. The results from CFD were compared with those previously acquired from wind tunnel tests.   Ã‚   The building proposed for the study consists of a rectangular box with two openings of equal size located opposite to each other. The wind is simulated from 0 °(Case 1) and 90 °(Case 2) to the building at a rate of 1m/sec, to study the flow pattern in and around it. When the air approaches the building the ventilation rate is unsteady at the mouth of the openings due to turbulence and in the flow separation layer due to shear. In Case 1 the wind is accelerated through the opening and directed downwards inside the building. This phenomenon brings about a circulation of the internal air before guiding the wind upwards and out through the window on the leeward side of the building. The air exchange occurs due to the mean flows through the opening. In Case 2 where the wind is parallel to the windows, the air moves in and exits rapidly causing fluctuating flows thereby leading to air exchange. In this case turbulence prone areas are formed at the rear of the building. When these results were compared with the wind tunnel data, Case 1 portrayed similarities while Case 2 had major deviations. Further study was proposed for understanding the reason behind such deviations. Case studies The Bahrain world trade centre was the world’s first building to ‘aesthetically incorporate commercial wind turbines into the fabric of the building’ [ ]. The complex consists of a three-storied sculpted podium and basement from where the 240m high towers rise up into the sky. The two towers comprise of 51 floors each and are connected by means of three, 31.5m span bridges at 60m, 96m and 132m levels [ ]. They are oval in section for aerodynamic reasons and follow a shallow V-shape in plan for adequate blade clearance. Sitting on each of this 70 ton spandrel is an 11-ton nacelle to which the industry approved horizontal axis wind turbines are fixed by special means. The turbine has a rotor diameter of 29m and is stall controlled with centrifugally activated feathering tips for air brakes (Killa S Smith Richard F, 2008). The turbines are oriented facing the Arabian Gulf intercepting the path of the dominant winds. The decision to harness the prevailing wind was thought of from the initial stage drawing inspiration from ‘the regional wind towers and the vast sails of the traditional Arabian Dhow which utilise the wind to drive them forward’. Numerous Computational fluid dynamics models and wind tunnel tests were carried out to determine the final building form. The result was a skyward tapering, elliptical structure, carved out by the wind that functions as aerofoil sections (Wood A, 2008). The shape and spatial relationship of the towers aid in adhering the wind in a â€Å"S’ flow whereby the center of the wind stream remains nearly perpendicular to the turbine within a 45 ° wind azimuth, either side of the central axis (Killa S Smith Richard F, 2008). This increases the turbine efficiency, number of working hours and minimizes the stress on the blade caused by yawing [ ]. Furthermore, the two towers were placed such that they create a ‘V’ shaped space in between them, as well as a negative pressure behind the blocks, thus creating an opportunity for the Venturi effect to accelerate wind velocity onto the turbines (Binder G, 2006) by as much as 30% more than the source wind (Killa S Smith Richard F, 2008). The tapering profile combined with the increased onshore wind velocity at higher altitudes creates a near equal regime of wind speed on each of the three turbines, irrespective of its location, allowing them to rotate at the same speed and generate approximately the same amount of energy (Wood A, 2008). Table 1: Annual energy output

Personal Life of Babe Ruth :: essays research papers

Not all American legends live a wonderful life. For example, there was Babe Ruth. In the early years of the 1900's, the baseball life of 'The Great Bambino' had begun. The legend of Babe Ruth, born George Ruth, Jr., is considered by many to be the greatest baseball player. For instance, everybody knows how great a hitter Babe was, and virtually invented the homerun. But, not everybody knows what a great person he was when it came to children. Babe Ruth possessed the attribute of being brutal and incorrigible. He had many distinct characteristics. He is known primarily for his great baseball exploits and secondary as a man who stayed out late before every game and partied until there was no one left to party with. There is more behind the story of Babe Ruth than just baseball and parties. For instance, as a boy, Ruth was your average youth who got himself into a little too much trouble and really paid the price for it. He stole from stores, he skipped school, and chewed tobacco at the age of seven. His father often beat him because he thought young George was incorrigible. So his father took him to an orphanage. Not only did his father sent him to an orphanage, but signed over custody of his son to the Xaverian Brothers, whom were missionaries that ran St. Mary?s. St. Mary?s was the orphanage that Babe Ruth grew up at. Even though Babe did not realize it at the time, he came into a good thing. That?s where he met Brother Matthias, his mentor. Brother Matthias took young Ruth under his wing and taught him to read, write, do needle work, play baseball, and right from wrong. Ruth showed startling natural talent with a bat, so Brother Matthias tried to round young George into a complete baseball player by teaching him to pitch and outfield. Ruth said, ?Brother Matthi as was the greatest man I ever knew?. Soon after, Babe changed the game of baseball. Ruth is perhaps the most recognized player in Major league Baseball history. Where he was, the fans followed, the attendance was always the greatest in his presence. He is by far America?s greatest sports hero. Aside from being a great ball player, he was also a husband and a father. He cared more for his family than he liked to show. Personal Life of Babe Ruth :: essays research papers Not all American legends live a wonderful life. For example, there was Babe Ruth. In the early years of the 1900's, the baseball life of 'The Great Bambino' had begun. The legend of Babe Ruth, born George Ruth, Jr., is considered by many to be the greatest baseball player. For instance, everybody knows how great a hitter Babe was, and virtually invented the homerun. But, not everybody knows what a great person he was when it came to children. Babe Ruth possessed the attribute of being brutal and incorrigible. He had many distinct characteristics. He is known primarily for his great baseball exploits and secondary as a man who stayed out late before every game and partied until there was no one left to party with. There is more behind the story of Babe Ruth than just baseball and parties. For instance, as a boy, Ruth was your average youth who got himself into a little too much trouble and really paid the price for it. He stole from stores, he skipped school, and chewed tobacco at the age of seven. His father often beat him because he thought young George was incorrigible. So his father took him to an orphanage. Not only did his father sent him to an orphanage, but signed over custody of his son to the Xaverian Brothers, whom were missionaries that ran St. Mary?s. St. Mary?s was the orphanage that Babe Ruth grew up at. Even though Babe did not realize it at the time, he came into a good thing. That?s where he met Brother Matthias, his mentor. Brother Matthias took young Ruth under his wing and taught him to read, write, do needle work, play baseball, and right from wrong. Ruth showed startling natural talent with a bat, so Brother Matthias tried to round young George into a complete baseball player by teaching him to pitch and outfield. Ruth said, ?Brother Matthi as was the greatest man I ever knew?. Soon after, Babe changed the game of baseball. Ruth is perhaps the most recognized player in Major league Baseball history. Where he was, the fans followed, the attendance was always the greatest in his presence. He is by far America?s greatest sports hero. Aside from being a great ball player, he was also a husband and a father. He cared more for his family than he liked to show.

Let Freedom Ring Essay example -- Civil Rights Movement Equality Paper

Let Freedom Ring The Civil Rights Movement was the catalyst, the march that ignited the flame of justice in the twentieth century. It coerced America as a nation to reevaluate itself, to reevaluate what it stood for.... We hold these truths to be self-evident†¦ Hot, black coffee trickled down the dark skin on Henry Moses’ back. †¦that all men are created equal†¦ â€Å"Get out of here, nigger! Go back to your kind!† an angry White man shouted as he continued pouring. †¦that they are endowed by their Creator with certain unalienable rights†¦ Moses sat silently, keeping his seat at the lunch counter in downtown Jackson. †¦that among these are life†¦ Lunch counter stools were for White folks only. It had always been that way. Moses, just 21, knew that. †¦liberty†¦ â€Å"It was just a part of their heritage,† he says now. â€Å"They thought that Negroes were filthy†¦ scum. Just somebody you don’t associate with. You don’t wait on ‘em, you don’t cut ‘em no slack whatsoever. This is just the way that they had been taught, the way they had been trained.† †¦and the pursuit of happiness. â€Å"And we were trying to change it† (â€Å"First in News†). Since the discovery of the new world by Europeans, Blacks--with the exception of the Native American Indians--have suffered immensely more than any other group in America. From the time the first African slaves stepped on American soil, their destiny changed forever. For over four hundred years, Blacks worked on fields and in homes of their White masters with no concept of civil rights in their daily lives. It was not until 1863, when President Abraham Lincoln read the Emancipation Proclamation, abolishing slavery, that civil rights and freedom became a possibility for millions of African-Americans. Soon th... ...story. New York: John Wiley & Sons, Inc. 1997. Bell, Derrick. Afrolantica Legacies. Chicago: Third World Press. 1998. Brink, William and Harris, Louis. Black and White. New York: Simon and Schuster. 1967. Button, James W. Blacks and Social Change: Impact of the Civil Rights Movement in the Southern Communities. Princeton: Princeton University Press, 1989. â€Å"First in News.† The Jackson Sun. 6 Nov. 2002. . Gates, Henry Louis, et al. African American: Voices of Triumph. Alexandria Time Life Books, 1993. Sullivan, Patricia. â€Å"Civil Rights Movement.† Africana: the Gateway to the Black World. 10 Nov. 2002. . â€Å"We Shall Overcome.† The National Park Services: Links to the Past. 6 Nov. 2002. .

The 1893 World’s Fair Essay examples -- Arts Worlds Fair Essays

The 1893 World’s Fair A World’s Fair is an â€Å"[I]nternational exposition that features exhibits dealing with commerce, industry, and science.† (World Book Encyclopedia 412) Entertainment is also present along with cultural activities. In 1893, the World’s Columbian Exposition in Chicago, although inaugurated a year late, commemorated the discovery of America. I feel that the Exposition displayed some of the more beautiful architecture of its time; its immense buildings and sculptures drew heavily from Greek and other classical styles, and it could possible be because of the sweeping popularity in Beaux Arts architecture. The Peristyle, one of the buildings that was constructed for the Fair, was designed by Charles B. Atwood. It was an ‘arcade of columns originally proposed by Augustus Saint Gaudens, the consultant on sculpture.† (Burg 79) The Perisytle was a beautiful building that followed in the traditional Greek pathway. It â€Å"was a series of forty-eight Corinthian columns, one for each of the American States and Territories, with an immense triumphal arch at the center. J The Peristyle itself was 500’ high, its top being a broad promenade populated by 85 allegorical figures in heroic scale.† (Burg 119) The Greeks used Peristyles in their architecture. A Peristyle was placed around the Greek Parthenon. Corinthian columns were created in the Hellenic era, but they had to wait until the Hellenistic era to reach their full development. J â€Å"They are distinguished by their ornate capitals with double rows of acanthus leaves and fernlike fonds rising from each corner and terminating in miniature volutes.† (Fleming 32) The largest structure at the fair was the Manufactures and Liberal Arts Building. It housed many... ...ssive of the greatest eras of human history.† (Burg 175) It’s a shame that after all the work, and all of the visitors, and all the critics’ reviews, in the end the buildings have to be torn down! Bibliography No author cited. â€Å"World’s Fair.† World Book Encyclopedia. 1896 ed. Hunt, William Dudley Jr. â€Å"Beaux Arts, Ecole Des.† Hunt Encyclopedia of American Architecture, 1980 ed. Books Burg, David F. Chicago’s White City of 1893. Kentucky: The University Press of Kentucky, 1976. No author cited. The Columbian World’s Fair Atlas. Ohio: W.F. Towns 1891. Fleming, William. Arts and Ideas. 8th ed. Florida: Holt, Rinehart, and Winston, Incorporated, 1991. No author cited. The American Heritage Dictionary. Boston: Houghton Mifflin Company, 1985. Newspaper No author cited. â€Å"A City of White Elephants.† New York Times 18 Sept. 1893, natl.ed.,8.

First Day of High School Essay

Walking into a brand new school for the first time with a bundle of happiness and a twisted knot in your stomach indicating just how nervous you really are, sure is a way to start your first day of high school. It is natural on the part of every student to remember the first day at school. Recently, I just became a 9th grader. I remember the day as a unclear haze, that resembled a impossible puzzle to complete. The night before was spent with stories of high school back in the last couple decades or so. Ever so often was an, â€Å"Oh you’ll blend in,† â€Å"You’ve grown so much,† and â€Å"I cannot believe you’re already in high school.† Eventually the praise died down and it was time to climb into bed. The first thing I came to realize was a large building pacted tightly together within a compound wall. As small as I am, i couldn’t not seem to put the puzzle pieces together but luckily a map became my bestfriend. The schedule was confusing at first, since it was a long summertime before I had last read one. Nothing felt stable or ordered, everything seemed like it was going to be chaotic any minute. A few seconds later the bell rang, as I thought to myself how much I did not ever recall a harsh stop and ponder during the summer about miss the bell itself. The pattern went throughout the day as a class began, and after a long period a bell ended the period and began a new class. This went on for what felt like years. I walked through the halls and tried to categorize exactly what type of people I would be dealing with and I’ve realized the fact high school is anything but the type of events they describe in movies. Everyone seemed to fit each category perfectly, however it wasn’t quite the match. These faces appeared more normal and friendly. I remember my imagination of what high school was like when I was younger. I was just dying to experience all the new and exciting things that awaited me. From sports to boys to all the partying, I just wanted to know what everything was like and now that I’m finally here, I feel like I want to go back to when I was younger and not wish to grow up so much. As time goes on you find yourself getting to class earlier and earlier each day. Finding new routes, talking a little more, taking more time between  classes and the tension eases. The days do not get harder, but the work and study habits do. Later days of the school year are always easier then the first few. Some say that â€Å"high school was the best time of my life†, just like others say that high school was the worst time in their lives. To be honest, I am not sure which category I fall into yet. I’ve had a good start but I know high school won’t be picture perfect for me. The only thing I can say is that I am learning.