529 resultados para power factor correction (PFC)


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Laminar two-dimensional natural convection boundary-layer flow of non-Newtonian fluids along an isothermal horizontal circular cylinder has been studied using a modified power-law viscosity model. In this model, there are no unrealistic limits of zero or infinite viscosity. Therefore, the boundary-layer equations can be solved numerically by using marching order implicit finite difference method with double sweep technique. Numerical results are presented for the case of shear-thinning as well as shear thickening fluids in terms of the fluid velocity and temperature distributions, shear stresses and rate of heat transfer in terms of the local skin-friction and local Nusselt number respectively.

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In this paper characteristic of a DBD (Dielectric Barrier Discharge) plasma lamp is investigated based on the lamp intensity and power consumption. A pulsed power supply with controllable parameters based on a push-pull converter is developed for lamp excitation at different voltage levels and repetition rate. The experimentations were conducted for 28 different operating points with the frequency range of 2 kHz to 15 Khz at output voltage levels of between 7.4 kV up to 13 kV. The obtained results show the feasibility of finding an optimum operation point due to nonlinear behaviour of the DBD lamp.

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In power hardware in the loop (PHIL) simulations, a real-time simulated power system is interfaced to a piece of hardware, usually called hardware under test (HuT). A PHIL test can be realized using several simulation tools. Among them Real Time Digital Simulator (RTDS) is an ideal tool to perform complex power system simulations in near real-time. Stable operation of the entire system, along with the accuracy of simulation results are the main concerns regarding a PHIL simulation. In this paper, a simulated power network on RTDS will be interfaced to HuT through a voltage source converter (VSC). Issues around stability and other interface problems are studied and a new method to stabilize some unstable PHIL cases is proposed. PHIL simulation results in PSCAD and RSCAD are presented.

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The question of the relationship between culture and power continues to exercise researchers. In this paper I argue that it is useful to consider the differences between ‘art’ and ‘entertainment’ as systems of culture, each involving a distinct set of power relationships between producers and audiences. Art wants to change audiences; entertainment wants to be changed by audiences. From these different starting points a series of differences unfold in the power possessed by producers and audiences. Artists pride themselves in not involving the audience in the process of making art. By contrast, entertainment wants audiences to contribute to the making of texts. As to the question of who controls the range of what forms of culture are available, it seems that entertainment consumers – unlike art consumers – are ill-disciplined. Historical evidence demonstrates that if legal corporate providers do not offer the kinds of entertainment they want, they will turn to illegal sources. The different ways in which ‘art’ and ‘entertainment’ function as cultural systems suggest that we must rethink our positions on ‘media power’.

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The aim of this study is to investigate the compliance impact of price queries issued by a securities market operator to its participating firms. Market operators in Australia and New Zealand, such as the Australian Securities Exchange and the New Zealand Securities Exchange, have the regulatory power in their rules to issue queries to its market participants to explain unusual fluctuations in trading price or volume in the market. The operator will issue a price query where it believes that the market has not been fully informed as to price relevant information. Responsive regulation has informed much of the regulatory debate in securities laws in our region. We posit that price queries are one strategy that a market operator can use in communicating its enforcement expectations to its stakeholder. However, whilst responsive regulation informs regulatory choices, an alternate view seeks to explain why participants respond to these regulatory strategies, and we use disclosure behaviour after price queries to test compliance behaviour

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Principal Topic Counties in Northern Europe, such as Sweden, Finland and Denmark, have comparatively low per capita rates of entrepreneurship as measured by independent new venture start-up rates – as for example measured by the Global Entrepreneurship Monitor (GEM) Total entrepreneurial activity (TEA) rate. However, the latest 2011 GEM data reveals that these same countries have comparatively very high Employee Entrepreneurship Activity (EEA) rates – that is a high rate per capita of employees involved in new product development or new enterprise activities. This observation has prompted us to investigate the role of national culture in driving independent versus employee entrepreneurial activities. Prior research has established that national (and regional) culture plays an important role in forming an “entrepreneurial culture” that encourages (or discourages) independent business start-ups and TEA (e.g. Davidsson, 1995; Beugelsdijk, 2007). However, the relationship of culture and EEA has not received research attention. Moreover, empirical relationships between elements of national culture and independent entrepreneurship have revealed some surprising results. For example, Wildeman et al. (1999) report an unexpected higher share of individual business ownership in countries that have higher uncertainty avoidance, higher power distance and lower individualism according to Hofstede’s dimensions of culture. They speculate that dissatisfaction can be a source of entrepreneurship: in countries with a high power distance, a high uncertainty avoidance and low individualism, there may be relatively more business owners since enterprising individuals cannot satisfy their needs within existing organizations. Yet it remains a rather open question whether entrepreneurial behaviour in existing organisations provides a satisfactory explanation for these empirical findings. Methods We will conduct a cross sectional study of the influence of national culture according to the five / six dimensions of Hofstede (1980; 2001) on both TEA and EEA for the 54 countries that participated in GEM 2011. Since it is well established that the opportunities for entrepreneurship vary substantially with a country’s level of economic development, we intend to conduct separate analyses for the three categories of development – innovation driven economies, efficient driven economies and factor driven economies. We also intend to restrict our assessment of TEA to opportunity driven entrepreneurship, as necessity driven entrepreneurship has a different relationship to the “entrepreneurial culture” that is the focus of our study. We will control for a range of factors such as GDP growth, ease of doing business index and unemployment. Results and Implications Descriptive analyses of the GEM TEA and EEA data reveal clusters of countries that appear to be have similar national culture. We are yet to conduct regression analyses.

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The purpose of this study was to determine factors (internal and external) that influenced Canadian provincial (state) politicians when making funding decisions about public libraries. Using the case study methodology, Canadian provincial/state level funding for public libraries in the 2009-10 fiscal year was examined. After reviewing funding levels across the country, three jurisdictions were chosen for the case: British Columbia's budget revealed dramatically decreased funding, Alberta's budget showed dramatically increased funding, and Ontario's budget was unchanged from the previous year. The primary source of data for the case was a series of semi-structured interviews with elected officials and senior bureaucrats from the three jurisdictions. An examination of primary and secondary documents was also undertaken to help set the political and economic context as well as to provide triangulation for the case interviews. The data were analysed to determine whether Cialdini's theory of influence (2001) and specifically any of the six tactics of influence (i.e, commitment and consistency, authority, liking, social proof, scarcity and reciprocity) were instrumental in these budget processes. Findings show the principles of "authority", "consistency and commitment" and "liking" were relevant, and that "liking" were especially important to these decisions. When these decision makers were considering funding for public libraries, they most often used three distinct lenses: the consistency lens (what are my values? what would my party do?), the authority lens (is someone with hierarchical power telling me to do this? are the requests legitimate?), and most importantly, the liking lens (how much do I like and know about the requester?). These findings are consistent with Cialdini's theory, which suggests the quality of some relationships is one of six factors that can most influence a decision maker. The small number of prior research studies exploring the reasons for increases or decreases in public library funding allocation decisions have given little insight into the factors that motivate those politicians involved in the process and the variables that contribute to these decisions. No prior studies have examined the construct of influence in decision making about funding for Canadian public libraries at any level of government. Additionally, no prior studies have examined the construct of influence in decision making within the context of Canadian provincial politics. While many public libraries are facing difficult decisions in the face of uncertain funding futures, the ability of the sector to obtain favourable responses to requests for increases may require a less simplistic approach than previously thought. The ability to create meaningful connections with individuals in many communities and across all levels of government should be emphasised as a key factor in influencing funding decisions.

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The ongoing crises of child sexual abuse by Christian institutions leaders across the Anglophone world continue to attract public attention and public inquiries. The pervasiveness of this issue lends credence to the argument that the prevailing ethos functioning within some Christian Institutions is one which exercises influence to repeatedly mismanage allegations of child sexual abuse by Church leaders. This work draws on semistructured interviews conducted with 15 Personnel in Christian Institutions (PICIs) in Australia who were identified as being pro-active in their approach to addressing child sexual abuse by PICIs. From these data, themes of power and forgiveness are explored through a Foucaultian conceptualising of pastoral power and ‘truth’ construction. Forgiveness is viewed as a discourse which can have the power effect of either silencing or empowering victim/survivors. The study concludes that individual PICIs’ understandings of the role ofpower in their praxis influences outcomes from the deployment of forgiveness.

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What role does China play in Western imagination and how does it affect Western selfconceptions? The rise of China as an alternative model to Western liberalism has created a fear that developing countries will stray from Western standards of democracy, transparency and human rights. However, such fears often say as much about those who hold them as they do about China itself. In this short and easily readable book Barr holds a mirror to Sino–Western relations in order to better understand how the West’s own past, hopes and fears shape the way it thinks about and engages with China. Focusing on three key areas—models of development, soft power and ethnocentrism—he argues that the rise of China ‘hits a nerve in the Western psyche . . . because its actions reflect the West’s own ambivalence to modernity and uncertainty over the proper role and limits of state power’ (p. 21). To make his point, Barr focuses on China’s soft power and the connections between China’s domestic politics and its attempts to shape its image internationally...

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The reason why a sustained high concentration of insulin induces laminitis in horses remains unclear. Cell proliferation occurs in the lamellae during insulin-induced laminitis and in other species high concentrations of insulin can activate receptors for the powerful cell mitogen, insulin-like growth factor (IGF)-1. The first aim of this study was to determine if IGF-1 receptors (IGF-1R) are activated in the hoof during insulin-induced laminitis. Gene expression for IGF-1R and the insulin receptor (InsR) was measured using qRT-PCR, in lamellar tissue from control horses and from horses undergoing a prolonged euglycaemic, hyperinsulinaemic clamp (p-EHC), during the mid-developmental (24 h) and acute (46 h) phases of insulin-induced laminitis. Gene expression for both receptors was decreased 13–32-fold (P < 0.05) at both time-points in the insulin-treated horses. A second aim was to determine if the down-regulation of the receptor genes could be accounted for by an increase in circulating IGF-1. Serum IGF-1 was measured at 0, 10, 25 and 46 h post-treatment in horses given a p-EHC for approximately 46 h, and in matched controls administered a balanced, electrolyte solution. There was no increase in serum IGF-1 concentrations during the p-EHC, consistent with down-regulation of both receptors by insulin. Stimulation of the IGF-1R by insulin may lead to inappropriate lamellar epidermal cell proliferation and lamellar weakening, a potential mechanism for hyperinsulinaemic laminitis. Targeting this receptor may provide insights into the pathogenesis or identify a novel therapy for hyperinsulinaemic laminitis.

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Research into hyperinsulinemic laminitis has progressed significantly in recent years with the use of the prolonged-euglycemic, hyperinsulinemic clamp (p-EHC). Previous investigations of laminitis pathophysiology have focused on digital vascular dysfunction, inflammation, altered glucose metabolism within the lamellae, and lamellar basement membrane breakdown by metalloproteinases. The etiopathogenesis of laminitis occurring in association with hyperinsulinemia is yet to be fully characterized, but it may not involve these mechanisms. Insulin stimulates cellular proliferation and can also affect other body systems, such as the insulin-like growth factor (IGF) system. Insulin-like growth factor-1 (IGF-1) is structurally homologous to insulin and, like insulin, binds with strong affinity to a specific tyrosine kinase receptor on the cell surface to produce its effects, which include promoting cell proliferation. Receptors for IGF-1 (IGF-1R) are present in the lamellar epidermis. An alternative theory for the pathogenesis of hyperinsulinemic laminitis is that uncontrolled cell proliferation, mediated through both the insulin receptor (InsR) and IGF-1R, leads to lengthening, weakening, and failure of the lamellae. An analysis of the proliferative activity of lamellar epidermal cells during the developmental and acute phases of hyperinsulinemic laminitis, and lamellar gene expression of the InsR and IGF-1R was undertaken.

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Alan Jones's now infamous comment that women are destroying the joint' sparked a flurry of observations and interpretations in the national and international media and in the blogosphere about the motivations and meanings of such a statement. The overriding tone of this commentary was outrage - how dare an influential figure like Jones state with such blatant and provocative hostility that women are at best unsuitable for leadership and at worst, damaging our public and private institutions? The answers, as we have seen, are likely to be complex, but an alternative question could also be posed. Why the outrage? Public male figures have, throughout history, made derogatory, demeaning and sexist remarks about women, and the material effects of gender inequality continue to be felt- consider the gender pay gap and glass ceiling phenomenon for starters. So why did this particular comment ignite such widespread indignation and anger?

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This paper presents an Image Based Visual Servo control design for Fixed Wing Unmanned Aerial Vehicles tracking locally linear infrastructure in the presence of wind using a body fixed imaging sensor. Visual servoing offers improved data collection by posing the tracking task as one of controlling a feature as viewed by the inspection sensor, although is complicated by the introduction of wind as aircraft heading and course angle no longer align. In this work it is shown that the effects of wind alter the desired line angle required for continuous tracking to equal the wind correction angle as would be calculated to set a desired course. A control solution is then sort by linearizing the interaction matrix about the new feature pose such that kinematics of the feature can be augmented with the lateral dynamics of the aircraft, from which a state feedback control design is developed. Simulation results are presented comparing no compensation, integral control and the proposed controller using the wind correction angle, followed by an assessment of response to atmospheric disturbances in the form of turbulence and wind gusts

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This edited collection brings together internationally recognized scholars to explore Green Criminology through interdisciplinary lenses of power, justice and harm. The chapters provide innovative case study analyses from North America, Europe and Australia that seek to advance theoretical, policy and practice discourses about environmental harm. This book brings together transnational debates in environmental law, policy and justice. In doing so, it examines international agreements and policy within diverse environmental discourses of sociology, criminology and political economy.

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This paper provides a new general approach for defining coherent generators in power systems based on the coherency in low frequency inter-area modes. The disturbance is considered to be distributed in the network by applying random load changes which is the random walk representation of real loads instead of a single fault and coherent generators are obtained by spectrum analysis of the generators velocity variations. In order to find the coherent areas and their borders in the inter-connected networks, non-generating buses are assigned to each group of coherent generator using similar coherency detection techniques. The method is evaluated on two test systems and coherent generators and areas are obtained for different operating points to provide a more accurate grouping approach which is valid across a range of realistic operating points of the system.