970 resultados para power device
Resumo:
Empire is central to U.S. history. When we see the U.S. projecting its influence on a global scale in today s world it is important to understand that U.S. empire has a long history. This dissertation offers a case study of colonialism and U.S. empire by discussing the social worlds, labor regimes, and culture of the U.S. Army during the conquest of southern Arizona and New Mexico (1866-1886). It highlights some of the defining principles, mentalities, and characteristics of U.S. imperialism and shows how U.S. forces have in years past constructed their power and represented themselves, their missions, and the places and peoples that faced U.S. imperialism/colonialism. Using insights from postcolonial studies and whiteness studies, this work balances its attention between discursive representations (army stories) and social experience (army actions), pays attention to silences in the process of historical production, and focuses on collective group mentalities and identities. In the end the army experience reveals an empire in denial constructed on the rule of difference and marked by frustration. White officers, their wives, and the white enlisted men not only wanted the monopoly of violence for the U.S. regime but also colonial (mental/cultural) authority and power, and constructed their identity, authority, and power in discourse and in the social contexts of the everyday through difference. Engaged in warfare against the Apaches, they did not recognize their actions as harmful or acknowledge the U.S. invasion as the bloody colonial conquest it was. White army personnel painted themselves and the army as liberators, represented colonial peoples as racial inferiors, approached colonial terrain in terms of struggle, and claimed that the region was a terrible periphery with little value before the arrival of white civilization. Officers and wives also wanted to place themselves at the top of colonial hierarchies as the refined and respectable class who led the regeneration of the colony by example: they tried to turn army villages into islands of civilization and made journeys, leisure, and domestic life to showcase their class sensibilities and level of sophistication. Often, however, their efforts failed, resulting in frustration and bitterness. Many blamed the colony and its peoples for their failures. The army itself was divided by race and class. All soldiers were treated as laborers unfit for self-government. White enlisted men, frustrated by their failures in colonial warfare and by constant manual labor, constructed worlds of resistance, whereas indigenous soldiers sought to negotiate the effects of colonialism by working in the army. As colonized labor their position was defined by tension between integration and exclusion and between freedom and colonial control.
Resumo:
Experimental results pertaining to the initiation, dynamics and mechanism of cavitation erosion on poly(methyl methacrylate) specimens tested in a rotating disk device are described in detail. Erosion normally starts at the location nearest to the center of rotation (CR). As the exposure time to cavitation increases, additional erosion areas or sites appear away from the CR and secondary erosion (induced by eroded pits) spreads upstream and merges with the main pit. The microcracks increase in density towards the end of the incubation period and transform into macrocracks in most cases. A study of light optical photographs and scanning electron micrographs of the eroded area shows that material particles are removed from the network of cracks because of crack joining and pits indicate particle debris. Optical degradation (loss of transmittance) is observed to be greater on the back of the specimen than on the front.
Resumo:
The power of projects has been demonstrated by the growth in their use across an increasing range of industries and workplaces in recent years. Not only has the number of people involved in project management increased, but the qualifications and backgrounds of those people have also broadened, with engineering no longer being the only path to project management (PM). Predicting the career trajectories in Project Management has become more important for both organisations employing project managers and project managers building career portfolios. Our research involved interviewing more than 75 project officers and project managers across a range of industries to explore their career journey. We used Wittgenstein’s family resemblance theory is to analyse the information from the transcripts to identify the extent to which the roles of participants fit with the commonly accepted definition of project management. Findings demonstrate diversity of project manager backgrounds and experiences and relational competencies across these backgrounds that form and shape PM careers.
Resumo:
The paper presents a new criterion for designing a power-system stabiliser, which is that it should cancel the negative damping torque inherent in a synchronous generator and automatic voltage regulator. The method arises from analysis based on the properties of tensor invariance, but it is easily implemented, and leads to the design of an adaptive controller. Extensive computations and simulation have been performed, and laboratory tests have been conducted on a computer-controlled micromachine system. Results are presented illustrating the effectiveness of the adaptive stabiliser.
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We discuss micro ring resonator based optical logic gates using Kerr-type nonlinearity. Resonant wavelength selectivity is one key factor in achieving the desired gate. Based on basic gates like AND gate, OR gate etc. We proceed to propose a 3-bit binary adder circuit.Due to the presence of more than a single wavelength, the system gets complicated as we increase the number of components in the circuit. Hence it has been observed that for efficient designing and functioning of digital circuits in optical domain, we need a device which can give single wavelength output, filtering out all other wavelengths and at the same time preserve the digital characteristics of the output. We propose such filter-preserver device based on micro ring resonator.
Resumo:
The paper presents a method for transmission loss charge allocation in deregulated power systems based on Relative Electrical Distance (RED) concept. Based on RED between the generator and load nodes and the predefined bilateral power contracts, charge evaluation is carried out. Generally through some power exchange mechanism a set of bilateral contracts are determined that facilitate bilateral agreements between the generation and distribution entities. In this paper the possible charges incurred in meeting loads like generation charge, transmission charge and charge due to losses are evaluated. Case studies have been carried out on a few practical equivalent systems. Due to space limitation results for a sample 5 bus system are presented considering ideal load/generation power contracts and deviated load/generation power contracts. Extensive numerical testing indicates that the proposed allocation scheme produces loss allocations that are appropriate and that behave in a physically reasonable manner.
Resumo:
In the paper new way of classifying spillways have been suggested. The various types, merits and demerits or existing spillway devices have been discussed. The considerations governing the choice of a design of a spillway have been mention. A criteria for working out the economics of spillway design has been suggested. An efficient surplus sing device has next been described and compared with other devices. In conclusion it has been suggested that the most efficient and at the same time economical arrangement will be a combination of devices. In conclusion it has been suggested will be a combination of crest gate, volute siphons and high head gates. The appendix gives a list of devices used in dams in various parts of the world.
Resumo:
The use of head-mounted displays (HMDs) can produce both positive and negative experiences. In an effort increase positive experiences and avoid negative ones, researchers have identified a number of variables that may cause sickness and eyestrain, although the exact nature of the relationship to HMDs may vary, depending on the tasks and the environments. Other non-sickness-related aspects of HMDs, such as users opinions and future decisions associated with task enjoyment and interest, have attracted little attention in the research community. In this thesis, user experiences associated with the use of monocular and bi-ocular HMDs were studied. These include eyestrain and sickness caused by current HMDs, the advantages and disadvantages of adjustable HMDs, HMDs as accessories for small multimedia devices, and the impact of individual characteristics and evaluated experiences on reported outcomes and opinions. The results indicate that today s commercial HMDs do not induce serious sickness or eyestrain. Reported adverse symptoms have some influence on HMD-related opinions, but the nature of the impact depends on the tasks and the devices used. As an accessory to handheld devices and as a personal viewing device, HMDs may increase use duration and enable users to perform tasks not suitable for small screens. Well-designed and functional, adjustable HMDs, especially monocular HMDs, increase viewing comfort and usability, which in turn may have a positive effect on product-related satisfaction. The role of individual characteristics in understanding HMD-related experiences has not changed significantly. Explaining other HMD-related experiences, especially forward-looking interests, also requires understanding more stable individual traits and motivations.
Resumo:
Failures in industrial organizations dealing with hazardous technologies can have widespread consequences for the safety of the workers and the general population. Psychology can have a major role in contributing to the safe and reliable operation of these technologies. Most current models of safety management in complex sociotechnical systems such as nuclear power plant maintenance are either non-contextual or based on an overly-rational image of an organization. Thus, they fail to grasp either the actual requirements of the work or the socially-constructed nature of the work in question. The general aim of the present study is to develop and test a methodology for contextual assessment of organizational culture in complex sociotechnical systems. This is done by demonstrating the findings that the application of the emerging methodology produces in the domain of maintenance of a nuclear power plant (NPP). The concepts of organizational culture and organizational core task (OCT) are operationalized and tested in the case studies. We argue that when the complexity of the work, technology and social environment is increased, the significance of the most implicit features of organizational culture as a means of coordinating the work and achieving safety and effectiveness of the activities also increases. For this reason a cultural perspective could provide additional insight into the problem of safety management. The present study aims to determine; (1) the elements of the organizational culture in complex sociotechnical systems; (2) the demands the maintenance task sets for the organizational culture; (3) how the current organizational culture at the case organizations supports the perception and fulfilment of the demands of the maintenance work; (4) the similarities and differences between the maintenance cultures at the case organizations, and (5) the necessary assessment of the organizational culture in complex sociotechnical systems. Three in-depth case studies were carried out at the maintenance units of three Nordic NPPs. The case studies employed an iterative and multimethod research strategy. The following methods were used: interviews, CULTURE-survey, seminars, document analysis and group work. Both cultural analysis and task modelling were carried out. The results indicate that organizational culture in complex sociotechnical systems can be characterised according to three qualitatively different elements: structure, internal integration and conceptions. All three of these elements of culture as well as their interrelations have to be considered in organizational assessments or important aspects of the organizational dynamics will be overlooked. On the basis of OCT modelling, the maintenance core task was defined as balancing between three critical demands: anticipating the condition of the plant and conducting preventive maintenance accordingly, reacting to unexpected technical faults and monitoring and reflecting on the effects of maintenance actions and the condition of the plant. The results indicate that safety was highly valued at all three plants, and in that sense they all had strong safety cultures. In other respects the cultural features were quite different, and thus the culturally-accepted means of maintaining high safety also differed. The handicraft nature of maintenance work was emphasised as a source of identity at the NPPs. Overall, the importance of safety was taken for granted, but the cultural norms concerning the appropriate means to guarantee it were little reflected. A sense of control, personal responsibility and organizational changes emerged as challenging issues at all the plants. The study shows that in complex sociotechnical systems it is both necessary and possible to analyse the safety and effectiveness of the organizational culture. Safety in complex sociotechnical systems cannot be understood or managed without understanding the demands of the organizational core task and managing the dynamics between the three elements of the organizational culture.
Resumo:
This thesis investigates China's film internationalism and coproduction strategy based on three cases: Hong Kong and China film coproduction; US and China without any state-level agreements; Australia and China based on an official coproduction treaty. It investigates the evolution of coproduction in the film industry, the process of coproduction, foreign film companies' strategies of adjustment to state policies, and the culture and complexities that hinder coproduction. It surveys the current environment for China film coproduction and investigates the degree to which film coproduction has been - to this stage - a contributor to China's global cultural presence – its soft power.
Resumo:
The short duration of the Doppler signal and noise content in it necessitate a validation scheme to be incorporated in the electronic processor used for frequency measurement, There are several different validation schemes that can be employed in period timing devices. A detailed study of the influence of these validation schemes on the measured frequency has been reported here. These studies were carried out by using a combination of a fast A/D converter and computer. Doppler bursts obtained from an air flow were digitised and stored on magnetic discs. Suitable computer programs were then used to simulate the performance of period timing devices with different validation schemes and the frequency of the stored bursts were evaluated. It is found that best results are obtained when the validation scheme enables frequency measurement to be made over a large number of cycles within the burst.
Resumo:
Ms Breathless is a 59-year-old lady living with chronic obstructive pulmonary disease (COPD) for several years now, and quit smoking over 20 years ago. She sometimes experiences symptoms of breathlessness, and an unrelenting productive cough, particularly when she comes in contact with dusty places, second-hand smoke, or when her allergies and hay fever play up. Apart from these triggers, her symptoms are well maintained with her inhalers glycopyrronium bromide (Seebri) and indacaterol (Onbrez), and she has been using them for about nine months. Ms Breathless is otherwise healthy, and not taking any other medicines.
Resumo:
The critical stream power criterion may be used to describe the incipient motion of cohesionless particles of plane sediment beds. The governing equation relating ``critical stream power'' to ``shear Reynolds number'' is developed by using the present experimental data as well as the data from several other sources. Simultaneously, a resistance equation, relating the ``particle Reynolds number'' to the``shear Reynolds number'' is developed for plane sediment beds in wide channels with little or no transport. By making use of these relations, a procedure is developed to design plane sediment beds such that any two of the four design variables, including particle size, energy/friction slope, flow depth, and discharge per unit width in the channel should be known to predict the remaining two variables. Finally, a straightforward design procedure using design tables/design curves and analytical methods is presented to solve six possible design problems.
Resumo:
In this paper, a novel 12-sided polygonal space vector structure is proposed for an induction motor drive. The space vector pattern presented in this paper consists of two 12-sided concentric polygons with the outer polygon having a radius double the inner one. As compared to previously reported 12-sided polygonal space vector structures, this paper subdivides the space vector plane into smaller sized triangles. This helps in reducing the switching frequency of the inverters without deteriorating the output voltage quality. It also reduces the device ratings and dv/dt stress on the devices to half. At the same time, other benefits obtained from the existing 12-sided space vector structure, such as increased linear modulation range and complete elimination of 5th and 7th order harmonics in the phase voltage, are also retained in this paper. The space vector structure is realized by feeding an open-end induction motor with two conventional three-level neutral point clamped (NPC) inverters with asymmetric isolated dc link voltage sources. The neutral point voltage fluctuations in the three-level NPC inverters are eliminated by utilizing the switching state multiplicities for a space vector point. The pulsewidth modulation timings are calculated using sampled reference waveform amplitudes and are explained in detail in this paper. Experimental verification on a laboratory prototype shows that this configuration may be considered suitable for high power drives.