981 resultados para multistage transmission expansion planning


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Yhteenveto: Veden laadun arviointi vesiensuojelun suunnittelussa

Relevância:

20.00% 20.00%

Publicador:

Resumo:

XVIII IUFRO World Congress, Ljubljana 1986.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thermal expansion of several compositions of Sr and Mg-doped LaGaO3 including an A-site deficient composition (La0.9Sr0.1)(0.98)(Ga0.8Mg0.2)O-2.821 were measured in the temperature range from 298 to 1273 K. The effect of doping on thermal expansion was studied by varying the composition at one site of the perovskite structure (either A or B), while keeping the composition at the other site invariant. Thermal expansion varied nonlinearly with temperature and exhibited an inflexion between 550 and 620 K, probably related to the change in crystal structure from orthorhombic to rhombohedral. The dependence of average thermal expansion coefficient (alpha (av)) on the dopant concentration on either A or B site of the perovskite structure was found to be linear, when the composition at the other site was kept constant. Mg doping on the B-site had a greater effect on the average thermal expansion coefficient than Sr doping on the A-site. Cation deficiency at the A-site decreases thermal expansion when compositions at both sites are held constant.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Details of an efficient optimal closed-loop guidance algorithm for a three-dimensional launch are presented with simulation results. Two types of orbital injections, with either true anomaly or argument of perigee being free at injection, are considered. The resulting steering-angle profile under the assumption of uniform gravity lies in a canted plane which transforms a three-dimensional problem into an equivalent two-dimensional one. Effects of thrust are estimated using a series in a recursive way. Encke's method is used to predict the trajectory during powered flight and then to compute the changes due to actual gravity using two gravity-related vectors. Guidance parameters are evaluated using the linear differential correction method. Optimality of the algorithm is tested against a standard ground-based trajectory optimization package. The performance of the algorithm is tested for accuracy, robustness, and efficiency for a sun-synchronous mission involving guidance for a multistage vehicle that requires large pitch and yaw maneuver. To demonstrate applicability of the algorithm to a range of missions, injection into a geostationary transfer orbit is also considered. The performance of the present algorithm is found to be much better than others.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper is concerned with the influence of different levels of complexity in modelling various constituent subsystems on the dynamic stability of power systems compensated by static var systems (SVS) operating on pure voltage control. The system components investigated include thyristor controlled reactor (TCR) transients, SVS delays, network transients, the synchronous generator and automatic voltage regulator (AVR). An overall model is proposed which adequately describes the system performance for small signal perturbations. The SVS performance is validated through detailed nonlinear simulation on a physical simulator.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Many next-generation distributed applications, such as grid computing, require a single source to communicate with a group of destinations. Traditionally, such applications are implemented using multicast communication. A typical multicast session requires creating the shortest-path tree to a fixed number of destinations. The fundamental issue in multicasting data to a fixed set of destinations is receiver blocking. If one of the destinations is not reachable, the entire multicast request (say, grid task request) may fail. Manycasting is a generalized variation of multicasting that provides the freedom to choose the best subset of destinations from a larger set of candidate destinations. We propose an impairment-aware algorithm to provide manycasting service in the optical layer, specifically OBS. We compare the performance of our proposed manycasting algorithm with traditional multicasting and multicast with over provisioning. Our results show a significant improvement in the blocking probability by implementing optical-layer manycasting.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Trafficking in human beings has become one of the most talked about criminal concerns of the 21st century. But this is not all that it has become. Trafficking has also been declared as one of the most pressing human rights issues of our time. In this sense, it has become a part of the expansion of the human rights phenomenon. Although it is easy to see that the crime of trafficking violates several of the human rights of its victims, it is still, in its essence, a fairly conventional although particularly heinous and often transnational crime, consisting of acts between private actors, and lacking, therefore, the vertical effect associated traditionally with human rights violations. This thesis asks, then, why, and how, has the anti-trafficking campaign been translated in human rights language. And even more fundamentally: in light of the critical, theoretical studies surrounding the expansion of the human rights phenomenon, especially that of Costas Douzinas, who has declared that we have come to the end of human rights as a consequence of the expansion and bureaucratization of the phenomenon, can human rights actually bring salvation to the victims of trafficking? The thesis demonstrates that the translation process of the anti-trafficking campaign into human rights language has been a complicated process involving various actors, including scholars, feminist NGOs, local activists and global human rights NGOs. It has also been driven by a complicated web of interests, the most prevalent one the sincere will to help the victims having become entangled with other aims, such as political, economical, and structural goals. As a consequence of its fragmented background, the human rights approach to trafficking seeks still its final form, consisting of several different claims. After an assessment of these claims from a legal perspective, this thesis concludes that the approach is most relevant regarding the mistreatment of victims of trafficking in the hands of state authorities. It seems to be quite common that authorities have trouble identifying the victims of trafficking, which means that the rights granted to themin international and national documents are not realized in practice, but victims of trafficking are systematically deported as illegal immigrants. It is argued that in order to understand the measures of the authorities, and to assess the usefulness of human rights, it is necessary to adopt a Foucauldian perspective and to observe the measures as biopolitical defence mechanisms. From a biopolitical perspective, the victims of trafficking can be seen as a threat to the population a threat that must be eliminated either by assimilating them to the main population with the help of disciplinary techniques, or by excluding them completely from the society. This biopolitical aim is accomplished through an impenetrable net of seemingly insignificant practices and discourses that not even the participants are aware of. As a result of these practices and discourses, trafficking victims only very few of fit the myth of the perfect victim, produced by biopolitical discourses become invisible and therefore subject to deportation as (risky) illegal immigrants, turning them into bare life in the Agambenian sense, represented by the homo sacer, who cannot be sacrificed, yet does not enjoy the protection of the society and its laws. It is argued, following Jacques Rancière and Slavoj i ek, that human rights can, through their universality and formal equality, provide bare life the tools to formulate political claims and therefore utilize their politicization through their exclusion to return to the sphere of power and politics. Even though human rights have inevitably become entangled with biopolitical practices, they are still perhaps the most efficient way to challenge biopower. Human rights have not, therefore, become useless for the victims of trafficking, but they must be conceived as a universal tool to formulate political claims and challenge power .In the case of trafficking this means that human rights must be utilized to constantly renegotiate the borders of the problematic concept of victim of trafficking created by international instruments, policies and discourses, including those that are sincerely aimed to provide help for the victims.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The effect of substitution of calcium on the anisotropic axial thermal expansion of cordierite was investigated by using a high-temperature X-ray diffraction technique. The compositions were prepared by the sol–gel route. In the Mg2-xCax-Al4Si5O18 system, single-phase cordierite can be prepared for x up to 0.5. Thermal expansion anisotropy (αa–αc) of cordierites reduces progressively by the substitution of increasing amounts of Ca for Mg.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A fairly comprehensive computer program incorporating explicit expressions for the four-pole parameters of concentric-tube resonators, plug mufflers, and three-duct cross-flow perforated elements has been used for parametric studies. The parameters considered are hole diameter, the center-to-center distance between consecutive holes (which decides porosity), the incoming mean flow Mach number, the area expansion ratio, the number of partitions of chambers within a given overall shell length, and the relative lengths of these partitions or chambers, all normalized with respect to the exhaust pipe diameter. Transmission loss has been plotted as a function of a normalized frequency parameter. Additionally, the effect of the tail pipe length on insertion loss for an anechoic source has also been studied. These studies have been supplemented by empirical expressions for the normalized static pressure drop for different types of perforated-element mufflers developed from experimental observations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The structures of Ca0.5Ti2P3O12 and Sr0.5Ti2P3O12, low-thermal-expansion materials, have been refined by the Rietveld method using high-resolution powder X-ray diffraction (XRD) data. The assignment of space group R[3 with combining macron] to NASICON-type compounds containing divalent cations is confirmed. 31P magic-angle spinning nuclear magnetic resonance (MASNMR) data are presented as supporting data. A comparison of changes in the polyhedral network resulting from the cation distribution, is made with NaTi2P3O12 and Nb2P3O12. Factors that may govern thermal expansion in this family of compounds are discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The paper is based on a study to develop carbon-glass epoxy hybrid composites with desirable thermal properties for applications at cryogenic temperatures. It analyzes the coefficient of thermal expansion of carbon-epoxy and glass-epoxy composite materials and compares it with the properties of carbon-glass epoxy hybrid composites in the temperature range 300 K to 125K. Urethane modified epoxy matrix system is used to make the composite specimens suitable for use even for temperatures as low as 20K. It is noted that the lay-up with 80% of carbon fibers in the total volume fraction of fibers oriented at 30 degrees and 20% of glass fibers oriented at 0 degrees yields near to zero coefficient of thermal expansion as the temperature is lowered from ambient to 125 K. (c) 2010 Elsevier Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The EEG time series has been subjected to various formalisms of analysis to extract meaningful information regarding the underlying neural events. In this paper the linear prediction (LP) method has been used for analysis and presentation of spectral array data for the better visualisation of background EEG activity. It has also been used for signal generation, efficient data storage and transmission of EEG. The LP method is compared with the standard Fourier method of compressed spectral array (CSA) of the multichannel EEG data. The autocorrelation autoregressive (AR) technique is used for obtaining the LP coefficients with a model order of 15. While the Fourier method reduces the data only by half, the LP method just requires the storage of signal variance and LP coefficients. The signal generated using white Gaussian noise as the input to the LP filter has a high correlation coefficient of 0.97 with that of original signal, thus making LP as a useful tool for storage and transmission of EEG. The biological significance of Fourier method and the LP method in respect to the microstructure of neuronal events in the generation of EEG is discussed.