635 resultados para Power loss


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In this chapter, the role of State Estimation (SE) in smart power grids is presented. The trend of SE error with respect to the increasing of the smart grids implementation investigated. The observability analysis as a prior task of SE is demonstrated and an analytical method to consider the impedance values of the branches is developed and discussed by examples. Since most principles of smart power grids are appropriate to distribution networks, the Distribution SE (DSE)considering load correlation is argued and illustrated by an example. The main features of smart grid SE, which is here named as “Smart Distributed SE” (SDSE), are discussed. Some characteristics of proposed SDES are distributed, hybrid, multi-micro grid and islanding support, Harmonic State Estimation (HSE), observability analysis and restore, error processing, and network parameter estimation. Distribution HSE (DHSE) and meter placement for SDSE are also presented.

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This thesis is a comparative textual analysis of Charles Bukowski's representations of power in relation to the idea of women. The exegesis explores Bukowski's idea of women and power as exemplified by the representational differences between his short stories for Hustler Magazine and his novel Women. The creative piece, a novel, "Many a Broken Hearted Woman" informed and was informed by this research.

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Integration of rooftop PVs and increasing peak demand in the residential distribution networks has resulted in unacceptable voltage profile. Curtailing PV generation to alleviate overvoltage problem and making regular network investment to cater peak demand is not always feasible. Reactive capability of the PV inverter can be a solution to address voltage dip and over voltage problems to some extent. This paper proposes an algorithm to utilize reactive capability of PV inverters and investigate their effectiveness on feeder length and R/X ratio of the line. Feeder loading level for a particular R/X ratio to have acceptable voltage profile is also investigated. Furthermore, the need of appropriate feeder distances and R/X ratio for acceptable voltage profile, which can be useful for suburban design and distribution planning, is explored.

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We introduce Kamouflage: a new architecture for building theft-resistant password managers. An attacker who steals a laptop or cell phone with a Kamouflage-based password manager is forced to carry out a considerable amount of online work before obtaining any user credentials. We implemented our proposal as a replacement for the built-in Firefox password manager, and provide performance measurements and the results from experiments with large real-world password sets to evaluate the feasibility and effectiveness of our approach. Kamouflage is well suited to become a standard architecture for password managers on mobile devices.

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The genomic changes that foster cancer can be either genetic or epigenetic in nature. Early studies focused on genetic changes and how mutational events contribute to changes in gene expression. These point mutations, deletions and amplifications are known to activate oncogenes and inactivate tumor suppressor genes. More recently, multiple epigenetic changes that can have a profound effect on carcinogenesis have been identified. These epigenetic events, such as the methylation of promoter sequences in genes, are under active investigation. In this review we will describe a methylation event that occurs during the propagation of human mammary epithelial cells (HMEC) in culture and detail the accompanying genetic alterations that have been observed.

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This case study was conducted to explore the perceptions of health risk messages sent by the Japanese Government following the Fukushima nuclear power plant disaster. The content of health risk messages from the Japanese Government and the Japanese national broadcaster (NHK) were analysed and semi-structured interviews were conducted with a sample of Tokyo residents. Initially, participants trusted these messages but as the crisis unfolded they became sceptical about the messages. Participants felt the messages did not communicate health risk information effectively because the messages were; not supported by evidence, inconsistent, delayed and changed over time. Despite widespread access to the internet, social media and mobile telephones, most participants relied on television news for information about the health risks. The Japanese Government urgently needs to re-build trust by engaging the community in the planning and development phases of health risk communication strategies.

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The University of Queensland (UQ) has extensive laboratory facilities associated with each course in the undergraduate electrical engineering program. The laboratories include machines and drives, power systems simulation, power electronics and intelligent equipment diagnostics. A number of postgraduate coursework programs are available at UQ and the courses associated with these programs also use laboratories. The machine laboratory is currently being renovated with i-lab style web based experimental facilities, which could be remotely accessed. Senior level courses use independent projects using laboratory facilities and this is found to be very useful to improve students' learning skill. Laboratory experiments are always an integral part of a course. Most of the experiments are conducted in a group of 2-3 students and thesis projects in BE and major projects in ME are always individual works. Assessment is done in-class for the performance and also for the report and analysis.

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The modern day Australian law school is expected to educate and engage law students. Ideally law school will instil a sense of passion (or at least appreciation) for the law, promote a positive professional identity, foster a sense of community, and provide general support to law students. Collectively, the Australian legal academy is struggling with these goals. Significant numbers of students feel isolated, disconnected and unengaged throughout their tertiary legal education. Teaching students from increasingly diverse backgrounds, who spend less time on campus and less face-to-face time in class, many law academics feel ill-equipped to respond to the challenge of engaging law students in time and cost efficient ways. Intentionally learning and using student names has potential to humanise the law school experience, build community, and positively impact upon the wellbeing of students and staff.

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"In this chapter the authors present a critique of Participatory Evaluation as worked in development projects, in this case, in Nepal. The article works between established claims that Participatory Evaluation builds capacity at programmatic and organisational levels, and the specific experiences of these claims in the authors’ current work. They highlight the need to address key difficulties such as high turn-over of staff and resulting loss of capacity to engage in Participatory Evaluation, and the difficulty of communication between academic as compared with local practical wisdoms. A key issue is the challenge of addressing the inevitable issues of power inequities that such approaches encounter. While Participatory Evaluation has been around for some time, it has only enjoyed more widespread recognition of its value in comparatively recent times, with its uptake in international development environments. To this extent, the practice is still in its early stages of development, and Jo, June and Michael’s work contributes to strengthening and more comprehensively understanding it. With regard to the meta-theme of this publication, this chapter is an example of how context not only influences the methodology to be used and the praxis of how it is to be used, but contributes to early explication of the core nature of an emerging methodology."

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A comparison of relay power minimisation subject to received signal-to-noise ratio (SNR) at the receiver and SNR maximisation subject to the total transmitted power of relays for a typical wireless network with distributed beamforming is presented. It is desirable to maximise receiver quality-of-service (QoS) and also to minimise the cost of transmission in terms of power. Hence, these two optimisation problems are very common and have been addressed separately in the literature. It is shown that SNR maximisation subject to power constraint and power minimisation subject to SNR constraint yield the same results for a typical wireless network. It proves that either one of the optimisation approaches is sufficient.

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The ion PhCO2--CHPh, upon collision activation, undergoes competitive losses of CO and CO2 of which the former process produces the base peak of the spectrum. Product ion and substituent effect (Hammett) studies indicate that PhCO2--CHPh cyclises to a deprotonated hydroxydiphenyloxirane which ring opens to PhCOCH(O-)Ph. This anion then undergoes an anionic 1,2-Wittig type rearrangement {through [PhCO- (PhCHO)]} to form Ph2CHO- and CO. The mechanism of the 1,2-rearrangement has been probed by an ab initio study [at MP4(SDTQ)/6-31++G(d,p) level] of the model system HCOCH2O- →; MeO- + CO The analogous system RCO2--CHPh (R = alkyl) similarly loses CO, and the migratory aptitudes of the alkyl R groups in this reaction are Bu′ > Me > Et ∼Pri). This trend correlates with the order of anion basicities (i.e. the order of ΔG○acid values of RH), supporting the operation of an anion migration process. The loss of CO2 from PhCO2--CHPh yields Ph2CH- as the anionic product: several mechanistic scenarios are possible, one of which involves an initial ipso nucleophilic substitution.

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The ortho, meta and para anions of methyl benzoate may be made in the source of a mass spectrometer by the S(N)2(Si) reactions between HO- and methyl (o-, m-, and p-trimethylsilyl)benzoate respectively. All three anions lose CO upon collisional activation to form the ortho anion of anisole in the ratio ortho>>meta > para. The rearrangement process is charge directed through the ortho anion. Theoretical calculations at the B3LYP/6-311++G(d,p)//HF/6-31+G(d) level of theory indicate that the conversion of the meta and para anions to the ortho anion prior to loss of CO involve 1,2-H transfer(s), rather than carbon scrambling of the methoxycarbonylphenyl anion. There are two mechanisms which can account for this rearrangement, viz. (A) cyclisation of the ortho anion centre to the carbonyl group of the ester to give a cyclic carbonyl system in which the incipient methoxide anion substitutes at one of the two equivalent ring carbons of the three membered ring to yield an intermediate which loses CO to give the ortho anion of anisole, and (B) an elimination reaction to give an intermediate benzyne-methoxycarbonyl anion complex in which the MeOCO- species acts as a MeO- donor, which then adds to benzyne to yield the ortho anion of anisole. Calculations at the B3LYP/6-311++G(d,p)//HF/6-31+G(d) level of theory indicate that (i) the barrier in the first step (the rate determining step) of process A is 87 kJ mol(-1) less than that for the synchronous benzyne process B, and (ii) there are more low frequency vibrations in the transition state for benzyne process B than for the corresponding transition state for process A. Stepwise process A has the lower barrier for the rate determining step, and the lower Arrhenius factor: we cannot differentiate between these two mechanisms on available evidence.

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We have previously observed that breast cancer cell lines could exhibit either epithelial or fibroblastic phenotypes as reflected by their morphologies and intermediate filament protein expression (C. L. Sommers, D. Walker-Jones, S. E. Heckford, P. Worland, E. Valverius, R. Clark, M. Stampfer, and E. P. Gelmann, Cancer Res., 49: 4258-4263, 1989). Fibroblastoid, vimentin-expressing breast cancer cell lines are more invasive in vitro and in vivo (E. W. Thompson, S. Paik, N. Brunner, C. L. Sommers, G. Zugmaier, R. Clarke, T. B. Shima, J. Torri, S. Donahue, M. E. Lippman, G. R. Martin, and R. B. Dickson, J. Cell. Physiol., 150: 534-544, 1992). We hypothesized that a breast cancer cell with an epithelial phenotype could undergo a transition to a fibroblastic phenotype, possibly resulting in more invasive capacity. We now show that two Adriamycin-resistant MCF-7 cell lines and a vinblastine-resistant ZR-75-B cell line have undergone such a transition. Adriamycin-resistant MCF-7 cells express vimentin, have diminished keratin 19 expression, have lost cell adhesion molecule uvomorulin expression, and have reduced formation of desmosomes and tight junctions as determined by reduced immunodetection of their components desmoplakins I and II and zonula occludens (ZO)-1. Other MCF-7 cell lines selected for resistance to vinblastine and to Adriamycin and verapamil did not have these characteristics, indicating that drug selection does not invariably cause these phenotypic changes. In addition, to determine if vimentin expression in MCF-7 cells alone could manifest a fibroblastic phenotype, we transfected the full-length human vimentin complementary DNA into MCF-7 cells. Although vimentin expression was achieved in MCF-7 cells, it did not affect the phenotype of the cells in terms of the distribution of keratins, desmoplakins I and II, ZO-1, or uvomorulin or in terms of in vitro invasiveness. We conclude that vimentin expression is a marker for a fibroblastic and invasive phenotype in breast cancer cells but does not by itself give rise to this phenotype.

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This study presents a general approach to identify dominant oscillation modes in bulk power system by using wide-area measurement system. To automatically identify the dominant modes without artificial participation, spectral characteristic of power system oscillation mode is applied to distinguish electromechanical oscillation modes which are calculated by stochastic subspace method, and a proposed mode matching pursuit is adopted to discriminate the dominant modes from the trivial modes, then stepwise-refinement scheme is developed to remove outliers of the dominant modes and the highly accurate dominant modes of identification are obtained. The method is implemented on the dominant modes of China Southern Power Grid which is one of the largest AC/DC paralleling grids in the world. Simulation data and field-measurement data are used to demonstrate high accuracy and better robustness of the dominant modes identification approach.