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Emergence of Spacetime: From Entanglement to EinsteinJanuary 2020 (has links)
abstract: Here I develop the connection between thermodynamics, entanglement, and gravity. I begin by showing that the classical null energy condition (NEC) can arise as a consequence of the second law of thermodynamics applied to local holographic screens. This is accomplished by essentially reversing the steps of Hawking's area theorem, leading to the Ricci convergence condition as an input, from which an application of Einstein's equations yields the NEC. Using the same argument, I show logarithmic quantum corrections to the Bekenstein-Hawking entropy formula do not alter the form of the Ricci convergence condition, but obscure its connection to the NEC. Then, by attributing thermodynamics to the stretched horizon of future lightcones -- a timelike hypersurface generated by a collection of radially accelerating observers with constant and uniform proper acceleration -- I derive Einstein's equations from the Clausius relation. Based on this derivation I uncover a local first law of gravity, connecting gravitational entropy to matter energy and work. I then provide an entanglement interpretation of stretched lightcone thermodynamics by extending the entanglement equilibrium proposal. Specifically I show that the condition of fixed volume can be understood as subtracting the irreversible contribution to the thermodynamic entropy. Using the AdS/CFT correspondence, I then provide a microscopic explanation of the 'thermodynamic volume' -- the conjugate variable to the pressure in extended black hole thermodynamics -- and reveal the super-entropicity of three-dimensional AdS black holes is due to the gravitational entropy overcounting the number of available dual CFT states. Finally, I conclude by providing a recent generlization of the extended first law of entanglement, and study its non-trivial 2+1- and 1+1-dimensional limits. This thesis is self-contained and pedagogical by including useful background content relevant to emergent gravity. / Dissertation/Thesis / Doctoral Dissertation Physics 2020
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Modelling Geochemical and Geobiological Consequences of Low-Temperature Continental SerpentinizationJanuary 2020 (has links)
abstract: The hydrous alteration of ultramafic rocks, known as serpentinization, produces some of the most reduced (H2 >1 mmolal) and alkaline (pH >11) fluids on Earth. Serpentinization can proceed even at the low-temperature conditions (<50°C) characteristic of most of Earth’s continental aquifers, raising questions on the limits of life deep in the subsurface and the magnitude in the flux of reduced volatiles to the surface. In this work, I explored the compositions and consequences of fluids and volatiles found in three low-temperature serpentinizing environments: (1) active hyperalkaline springs in ophiolites, (2) modern shallow and deep peridotite aquifers, and (3) komatiitic aquifers during the Archean.
Around 140 fluids were sampled from the Oman ophiolite and analyzed for their compositions. Fluid compositions can be accounted for by thermodynamic simulations of reactions accompanying incipient to advanced stages of serpentinization, as well as by simulations of mass transport processes such as fluid mixing and mineral leaching. Thermodynamic calculations were also used to predict compositions of end-member fluids representative of the shallow and deep peridotite aquifers that were ultimately used to quantify energy available to various subsurface chemolithotrophs. Calculations showed that sufficient energy and power supply can be available to support deep-seated methanogens. An additional and a more diverse energy supply can be available when surfacing deep-seated fluids mix with shallow groundwater in discharge zones of the subsurface fluid pathway. Finally, the consequence of the evolving continental composition during the Archean for the global supply of H2 generated through komatiite serpentinization was quantified. Results show that the flux of serpentinization-generated H2 could have been a significant sink for O2 during most of the Archean. This O2 sink diminished greatly towards the end of the Archean as komatiites became less common and helped set the stage for the Great Oxidation Event. Overall, this study provides a framework for exploring the origins of fluid and volatile compositions, including their redox state, that can result from various low-temperature serpentinizing environments in the present and past Earth and in other rocky bodies in the solar system. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2020
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Double Compression Expansion Engine: Evaluation of Thermodynamic Cycle and Combustion ConceptsShankar, Vijai 11 1900 (has links)
The efficiency of an internal combustion (IC) engine is governed by the thermodynamic cycle underpinning its operation. The thermodynamic efficiency of these devices is primarily determined by the temperature gradient created during the compression process. The final conversion efficiency also known as brake thermal efficiency (BTE) of IC engines, however, also depend on other processes associated with its operation. BTE is a product of the combustion, thermodynamic, gas-exchange, and mechanical efficiencies. The improvement of BTE through maximation of any one of the four efficiencies is reduced by its implication of the other three.
Split-cycle engine provides an alternative method of improving the engine efficiency through over-expansion of combustion gases by transferring it to a cylinder of greater volume. The operation of split-cycle engines is based on either the Brayton or the Atkinson Cycles. Atkinson Cycle has been demonstrated in IC engines without the split-cycle architecture but is limited by the reduced energy density.
Double Compression Expansion Engine (DCEE) provides a method of accomplishing the Atkinson Cycle without the constraints faced in conventional engine architectures. DCEE splits the compression and expansion processes in a vertical manner that enables the use of larger cylinder volumes for over-expansion as well as first-stage compression without much friction penalties.
The present thesis explores the thermodynamic cycle of this novel engine architecture using well-validated 1-dimensional engine models solving for gas-exchange, real gas properties, and heat transfer provided in the GT-Power software tool. The effect of compression ratio, rate of heat addition, sensitivity to design and modeling parameters was assessed and contrasted against conventional engine architecture. The synergies of combining low-temperature combustion (LTC) concepts with DCEE was investigated using simulation and experimental data. DCEE relaxes many constraints placed the operation of an engine in Homogenous Charge Compression Ignition (HCCI) mode. The limitations of adopting Partially Premixed Combustion (PPC) concept is also alleviated by the DCEE concept. BTE improvement of above 10% points is achievable through the DCEE concept along with possibility to achieve very low emissions through use of LTC concepts and new after-treatment methods uniquely available to the DCEE.
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Studie strukturních vlastností jednovláknových DNA biofyzikálními metodami a krystalograficky / Study of structural features of single stranded DNA by biophysical techniques and crystallographySvoboda, Jakub January 2021 (has links)
DNA is the fundamental molecule in all domains of life, its role in heredity is well established. Although the famous double helical complementary form is indispensable for replication mechanism DNA can occupy wide range of conformations. In the past studies performed in the laboratory, DNA oligomers related to single stranded bacterial Repetitive Extragenic Palindromic (REP) showed spectral behavior suggesting complex equilibria including double helical, hairpin, and tetraplex conformations. The studies presented in this thesis extended the scope of analyzed sequences and employed circular dichroism spectroscopy and X-ray crystallography. We report spectral data and X-ray structures of three successfully crystalized oligonucleotides. All three structures acquire double helical architecture with two consecutive T- T mismatches in the center. To improve the convergence of the refinement process of the crystal structures we used novel dinucleotide conformational classes, NtC classes. The NtC class classification was also used to analyze geometries of selected non-canonical base pairs in all DNA crystal structures in the Protein Data Bank. We measured the fit between geometries of the dinucleotides involved in the non-canonical base pairing and the NtC classes and correlated this fit to the electron...
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Model Relative Emergence in Physics / 物理学におけるモデル相対的な創発Morita, Kohei 23 March 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(文学) / 甲第22182号 / 文博第829号 / 新制||文||688(附属図書館) / 京都大学大学院文学研究科現代文化学専攻 / (主査)准教授 伊勢田 哲治, 教授 伊藤 和行, 准教授 大塚 淳 / 学位規則第4条第1項該当 / Doctor of Letters / Kyoto University / DGAM
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Extended Hydrodynamics Using the Discontinuous-Galerkin Hancock MethodKaufmann, Willem 15 September 2021 (has links)
Moment methods derived from the kinetic theory of gases can be used for the prediction of continuum and non-equilibrium flows and offer numerical advantages over other methods, such as the Navier-Stokes model. Models developed in this fashion are described by first-order hyperbolic partial differential equations (PDEs) with stiff local relaxation source terms.
The application of discontinuous-Galerkin (DG) methods for the solution of such models has many benefits. Of particular interest is the third-order accurate, coupled space-time discontinuous-Galerkin Hancock (DGH) method. This scheme is accurate, as well as highly efficient on large-scale distributed-memory computers.
The current study outlines a general implementation of the DGH method used for the parallel solution of moment methods in one, two, and three dimensions on modern distributed clusters. An algorithm for adaptive mesh refinement (AMR) was developed alongside the implementation of the scheme, and is used to achieve even higher accuracy and efficiency.
Many different first-order hyperbolic and hyperbolic-relaxation PDEs are solved to demonstrate the robustness of the scheme. First, a linear convection-relaxation equation is solved to verify the order of accuracy of the scheme in three dimensions. Next, some classical compressible Euler problems are solved in one, two, and three dimensions to demonstrate the scheme's ability to capture discontinuities and strong shocks, as well as the efficacy of the implemented AMR. A special case, Ringleb's flow, is also solved in two-dimensions to verify the order of accuracy of the scheme for non-linear PDEs on curved meshes. Following this, the shallow water equations are solved in two dimensions. Afterwards, the ten-moment (Gaussian) closure is applied to two-dimensional Stokes flow past a cylinder, showing the abilities of both the closure and scheme to accurately compute classical viscous solutions. Finally, the one-dimensional fourteen-moment closure is solved.
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Parní turbína pro spalovnu odpadu / Steam Turbine for Waste to EnergyHodonský, Lukáš January 2018 (has links)
The thesis deals with the design of the steam turbine for a waste incinerator. First, the concept and design of the machine is discussed. Following part is the steam turbine thermodynamics calculation, which is the main part of the thesis. My work also contains calculation of axial force and a simplified calculation of the gearbox. The design sections of individual modules and drawing of a disposition of a steam turbine are made on the based of the calculation.
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Simulation des thermischen Verhaltens asynchroner Traktionsmotoren im LastzyklusLehmann, Justin, Kopte, Jeanette 22 September 2021 (has links)
In diesem Beitrag wird das transiente thermische Verhalten eines asynchronen Traktionsmotors mittels eines Wärmequellennetzwerkes beschrieben. Anhand dieses Ansatzes gelingt es, Erwärmungsläufe für Nennbetriebsarten sowie für Lastzyklen unter Berücksichtigung von Umrichterverlusten und temperaturabhängigen Stromwärmeverlusten innerhalb des Entwurfsprozesses zu ermitteln. / The transient thermal behavior of an asynchronous traction motor is described through a thermal equivalent circuit in this paper. With this method it is possible to calculate the temperature rise for several duty types or load cycles within the design process under consideration of the converter losses and the temperature depending resistive losses.
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Stanovení parametrů křivky krevního tlaku / Determination of Blood PressurePlch, Miroslav January 2012 (has links)
The thesis includes a general introduction to monitoring and measurement of blood pressure of horses, the design of algorithms for pressure curve detection and the calculation of respiratory variabilities in mechanical ventilation under anaesthesia. The first two chapters focus on anatomy, on characteristics of blood flow and on vascular system. Then it deals with the measurement of blood pressure, monitoring of a horse under anaesthesia and it describes particular thermodynamic parameters. In the following part of the thesis, the methods of pressure curve detection are described. The last part contains the description of an algorithm designed for detection of pressure curve of horses in the environment of the program LabVIEW. The program calculates, displays and saves variabilities of systolic pressure, pulse volume, pressure amplitude, pulse frequency, peripheral resistance and vascular expansion from the detected values.
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Analýza vnitřní termodynamiky spalovacího motoru / Thermodynamic Analysis of Internal Combustion EngineČajka, Lukáš January 2010 (has links)
This thesis deals with analysis of the thermodynamics of the internal combustion engine. A survey on individual types of sensors used to measure pressure in combustion chamber is stated in the introductory part of the thesis. Another section deals with design of measuring chain. The main subject matter deals with compilation of the calculation program pertaining to the analysis of indicator diagram. Evaluation the results and procedures are included in the conclusion.
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