Angebote zu "Effects" (11 Treffer)

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Modeling, Analysis and Control of Effects of th...
59,00 € *
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The planar solid-oxide fuel cells (PSOFCs) have emerged as one of the promising candidates for future energy system because of their high energy efficiency, fuel flexibility, zero emission, modularity and high tolerance to the fuel impurities.However, for large-scale commercialization of the PSOFC technology, there is a strong need of developing a reliable and highly efficient PSOFC power system. Development of such a reliable PSOFC based power system requires knowledge of the several feedback effects from the power electronics system and the application loads that may impact the PSOFC stack and the system as a whole. Therefore, it is important to develop analytical methodologies to investigate and mitigate the effects of these electrical feedbacks on the performance of PSOFC systems.On the whole, the dissertation focuses on i) the modeling and development of an effective PSOFC power-system design and system interaction analyses, ii) cost-constrained PES topology design for PSOFCS and iii) the design of cost effective optimal controller and controlling strategy for mitigation of electrical impacts with higher system efficiency.

Anbieter: Dodax
Stand: 03.04.2020
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Strong Coupling Phenomena in Systems of Differe...
36,90 € *
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The possibility of confinement of photons in a microcavity and excitons in quantum wells opens a way to achievement of the strong light-matter coupling regime with the formation of elementary excitations known as polaritons (exciton polaritons, plasmon polaritons, etc) having hybrid half light half matter nature. This book is devoted to theoretical investigation of several aspects of the exciton-polariton physics, including (i) description of the relaxation dynamics of polaritons in real space and time using the density matrix formalism, (ii) investigation of nonlinear effects in terahertz emission from microvavities, (iii) investigation of the emission spectrum of a quantum dot with broken inversion symmetry embedded in a single-mode microcavity, (iv) investigation of the coupling between a giant plasmonic resonance of a metallic cluster and a cavity mode. The density matrix approach can be applied to two- and one-dimensional systems.Quantum dots and clusters represent zero-dimensional objects. Thus, two-, one- and zero-dimensional objects are considered.

Anbieter: Dodax
Stand: 03.04.2020
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Feasibility of Solar Thermal Collectors via Art...
55,90 € *
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Today, the concept of net zero- energy buildings has become a major concern regarding fossil fuels combustion side effects, such as air pollution or global warming. NG (Natural Gas) is a kind of fossil fuels which is widely combusted in Iran to meet various buildings heating demand. However, this research is proposed mitigating NG flaring by substituting solar energy as an auxiliary energy source in dwelling buildings and estimating accurate values of SGI (Solar Global Irradiance) on tilted planes via Artificial Neural Network (ANN) respectively. To fulfill this objective a solar thermal collector is designed which is either responsible to preheat water circulates in radiators loop, to provide space heating, or domestic hot water to supply washing demand in flats. Indeed, in case of utilizing this application fewer NG will be combusted for rising input water temperature to required value and fewer CO2 emission eventually. Also a dwelling complex including 136 apartments is considered perform this research. This complex is situated in Mashhad, the second megacity in Iran. Besides, to evaluate this potential four steps have been taking into account.

Anbieter: Dodax
Stand: 03.04.2020
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Tomorrow`s Energy - Hydrogen, Fuel Cells, and t...
41,90 CHF *
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Hydrogen is the most abundant element in the universe. An invisible, tasteless, colorless gas, it can be converted to nonpolluting, zero-emission, renewable energy. When burned in an internal combustion engine, hydrogen produces mostly harmless water vapor. It performs even better in fuel cells, which can be 2.5 times as efficient as internal-combustion engines. Zero-emission hydrogen does not contribute to CO2-caused global warming. Abundant and renewable, it is unlikely to be subject to geopolitical pressures or scarcity concerns. In this new edition of his pioneering book Tomorrow¿s Energy, Peter Hoffmann makes the case for hydrogen as the cornerstone of a new energy economy. Our current energy system is a complex infrastructure, and phasing in hydrogen will take effort and money. But if we consider the real costs of fossil fuels--pollution and its effects, international tensions over gas and oil supplies, and climate change--we would be wise to promote its development.

Anbieter: Orell Fuessli CH
Stand: 03.04.2020
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Pharmaceuticals in the Environment
229,00 CHF *
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When the first green wave appeared in the mid and late 1960s, it was considered a f- sible task to solve pollution problems. The visible problems were mostly limited to point sources, and a comprehensive “end of the pipe technology” (= environmental technology) was available. It was even seriously discussed in the US that what was called “zero d- charge” could be attained by 1985. It became clear in the early 1970s that zero discharge would be too expensive, and that we should also rely on the self purification ability of ecosystems. That called for the development of environmental and ecological models to assess the self purifi- tion capacity of ecosystems and to set up emission standards, considering the re- tionship between impacts and effects in the ecosystems. This idea is illustrated in Fig. 0.1. A model is used to relate an emission to its effect on the ecosystem and its components. The relationship is applied to select a good solution to environmental problems by application of environmental technology.

Anbieter: Orell Fuessli CH
Stand: 03.04.2020
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Pumping Yb:YAG thin-disks at 940 nm and the Zer...
41,90 CHF *
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Masterarbeit aus dem Jahr 2013 im Fachbereich Physik - Optik, Note: 1.3, Ludwig-Maximilians-Universität München, Sprache: Deutsch, Abstract: With the prospect of high-intensity isolated attosecond pulses XUV pump-XUV probe spectroscopy as well as novel methods for controlling atomic-scale currents seem feasible paving the way for new physical, chemical, biological, and medical applications such as attosecond X-ray diffraction, non-invasive imaging and cancer therapy. To reach these ambitious goals, optical parametric chirped pulse amplifcation (OPCPA) in combination with high harmonic generation (HHG) seems like a promising route. But this approach puts stringent demands on the pump laser driving it. To overcome these challenges Yb:YAG as active laser medium in a thin-disk geometry is often used offering a lot of favourable properties for high power applications with excellent beam quality. Yb:Yag can be pumped at either 940 nm or, more recently, since the advent of Volume-Bragg-Grating stabilized diodes, at its Zero-Phonon-Line with a wavelength of 969 nm. These two wavelengths excite different transitions in the 5 F 1/2 electronic shell each exhibiting its own assets and drawbacks. This thesis will focus on a comparison between them. A theoretical model of the conditions in the pumped thin-disk is created. Absorption of the pump light is calculated numerically. Amplified spontaneous emission and thermal effects are considered, too. The structure of the 5 F 1/2 energy manifold is accounted for thus allowing predictions for two different pumping wavelengths at 940 nm and 969 nm. To gauge the accuracy of the model the numerical calculations are compared with measurements conducted at LMU's newly-built Laboratory for Extreme Photonics. A regenerative amplifer is set up to quantify the roundtrip gain at different pumping powers and wavelengths. The temperature of the pumped disk and its deformations as well as the single pass gain are measured, too. All measurements are in reasonable agreement with theory. After the motivation for this work some basic properties of lasers are introduced. In chapter 3 the basics of thermodynamics and its application to laser gain media, especially Yb:YAG, will be covered. The previous considerations will be numerically applied to the case of a thin-disk regenerative amplifer in the 4. chapter. Additional aspects, like its cavity and nonlinear effects, will be considered, too. Chap. 5 will give a description of the experimental methods and setups used to check the numerical predictions while the raw measured data and its interpratation are stated chap. 6 and 7

Anbieter: Orell Fuessli CH
Stand: 03.04.2020
Zum Angebot
Tomorrow`s Energy - Hydrogen, Fuel Cells, and t...
29,99 € *
ggf. zzgl. Versand

Hydrogen is the most abundant element in the universe. An invisible, tasteless, colorless gas, it can be converted to nonpolluting, zero-emission, renewable energy. When burned in an internal combustion engine, hydrogen produces mostly harmless water vapor. It performs even better in fuel cells, which can be 2.5 times as efficient as internal-combustion engines. Zero-emission hydrogen does not contribute to CO2-caused global warming. Abundant and renewable, it is unlikely to be subject to geopolitical pressures or scarcity concerns. In this new edition of his pioneering book Tomorrow¿s Energy, Peter Hoffmann makes the case for hydrogen as the cornerstone of a new energy economy. Our current energy system is a complex infrastructure, and phasing in hydrogen will take effort and money. But if we consider the real costs of fossil fuels--pollution and its effects, international tensions over gas and oil supplies, and climate change--we would be wise to promote its development.

Anbieter: Thalia AT
Stand: 03.04.2020
Zum Angebot
Pharmaceuticals in the Environment
221,99 € *
ggf. zzgl. Versand

When the first green wave appeared in the mid and late 1960s, it was considered a f- sible task to solve pollution problems. The visible problems were mostly limited to point sources, and a comprehensive “end of the pipe technology” (= environmental technology) was available. It was even seriously discussed in the US that what was called “zero d- charge” could be attained by 1985. It became clear in the early 1970s that zero discharge would be too expensive, and that we should also rely on the self purification ability of ecosystems. That called for the development of environmental and ecological models to assess the self purifi- tion capacity of ecosystems and to set up emission standards, considering the re- tionship between impacts and effects in the ecosystems. This idea is illustrated in Fig. 0.1. A model is used to relate an emission to its effect on the ecosystem and its components. The relationship is applied to select a good solution to environmental problems by application of environmental technology.

Anbieter: Thalia AT
Stand: 03.04.2020
Zum Angebot
Modeling, Analaysis and Control Of Effects Of T...
53,99 € *
ggf. zzgl. Versand

The planar solid-oxide fuel cells (PSOFCs) have emerged as one of the promising candidates for future energy system because of their high energy efficiency, fuel flexibility, zero emission, modularity and high tolerance to the fuel impurities. However, for large-scale commercialization of the PSOFC technology, there is a strong need of developing a reliable and highly efficient PSOFC power system. Development of such a reliable PSOFC based power system requires knowledge of the several feedback effects from the power electronics system and the application loads that may impact the PSOFC stack and the system as a whole. Therefore, it is important to develop analytical methodologies to investigate and mitigate the effects of these electrical feedbacks on the performance of PSOFC systems. On the whole, the dissertation focuses on i) the modeling and development of an effective PSOFC power- system design and system interaction analyses, ii) cost-constrained PES topology design for PSOFCS and iii) the design of cost effective optimal controller and controlling strategy for mitigation of electrical impacts with higher system efficiency.

Anbieter: Thalia AT
Stand: 03.04.2020
Zum Angebot