Plasma heating via adiabatic magnetic compression-expansion cycle
Avinash, K.; Sengupta, M.; Ganesh, R.
2016-06-01
Heating of collisionless plasmas in closed adiabatic magnetic cycle comprising of a quasi static compression followed by a non quasi static constrained expansion against a constant external pressure is proposed. Thermodynamic constraints are derived to show that the plasma always gains heat in cycles having at least one non quasi static process. The turbulent relaxation of the plasma to the equilibrium state at the end of the non quasi static expansion is discussed and verified via 1D Particle in Cell (PIC) simulations. Applications of this scheme to heating plasmas in open configurations (mirror machines) and closed configurations (tokamak, reverse field pinche) are discussed.
International Nuclear Information System (INIS)
Highlights: • A multi-stage AA-CAES system model is established based on thermodynamic theory. • Four Cases about pressure loss and effectiveness of heat exchanger are investigated. • The impact of pressure loss on conversion of heat energy in TES is more sensitive. • The impact of heat exchanger effectiveness in charge process on system is stronger. • Pressure loss in heat exchanger affects the change trends of system efficiency. - Abstract: Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) is a large-scale energy storage system based on gas turbine technology and thermal energy storage (TES). Electrical energy can be converted into internal energy of air and heat energy in TES during the charge process, while reverse energy conversion proceeds during discharge process. The performance of AA-CAES system requires further improvement in order to increase efficiency. In this paper, a multi-stage AA-CAES system model is established, and the influence of effectiveness and pressure loss in heat exchanger on energy conversion and utilization efficiency of AA-CAES system is analyzed theoretically based on the theory of thermodynamics. Four Cases about effectiveness and pressure loss of heat exchanger are investigated and compared with each other. It is found that effectiveness and pressure loss of heat exchanger are directly related to energy conversion and utilization in AA-CAES system. System efficiency changes with the variation of heat exchanger effectiveness and the impact of pressure loss on conversion of heat energy in TES is more sensitive than that of internal energy of air. Pressure loss can cause the complexity of system efficiency change. With appropriate selection of the values of heat exchanger effectiveness for both charge and discharge processes, an AA-CAES system with a higher efficiency could be expected
Adiabatic Liquid Piston Compressed Air Energy Storage
DEFF Research Database (Denmark)
Petersen, Tage; Elmegaard, Brian; Pedersen, Allan Schrøder
This project investigates the potential of a Compressed Air Energy Storage system (CAES system). CAES systems are used to store mechanical energy in the form of compressed air. The systems use electricity to drive the compressor at times of low electricity demand with the purpose of converting...... the mechanical energy into electricity at times of high electricity demand. Two such systems are currently in operation; one in Germany (Huntorf) and one in the USA (Macintosh, Alabama). In both cases, an underground cavern is used as a pressure vessel for the storage of the compressed air. Both systems...... a turbine when discharging. In this case, the liquid works effectively as a piston compressing the gas in the vessel, hence the name “Adiabatic Liquid Piston Compressed Air Energy Storage” (ALP-CAES). The compression ratio of the gas in the vessel (ratio between maximum and minimum pressure) is relatively...
ADELE adiabatic compressed air energy storage. Status and perspectives
Energy Technology Data Exchange (ETDEWEB)
Freund, Sebastian [General Electric Deutschland Holding GmbH, Garching (Germany). GE Global Research Renewable Energy Systems Lab.; Marquardt, Roland; Moser, Peter [RWE Power AG, Essen (Germany). Research and Development Innovative Power Plant Technology
2013-06-01
This paper gives an overview about compressed air energy storage (CAES) technology and a summary of the ADELE programme, a multi-year R and D programme undertaken by a consortium led by RWE Power to develop adiabatic (A) CAES technology and commercialise the first plant. The ACAES technology is to utilise waste heat developing upon compression in order to increase the entire efficiency. The ADELE-ING project is to provide the basis for making the decision on the construction of a 85 MW prototype. (orig.)
When an Adiabatic Irreversible Expansion or Compression Becomes Reversible
Anacleto, Joaquim; Ferreira, J. M.; Soares, A. A.
2009-01-01
This paper aims to contribute to a better understanding of the concepts of a "reversible process" and "entropy". For this purpose, an adiabatic irreversible expansion or compression is analysed, by considering that an ideal gas is expanded (compressed), from an initial pressure P[subscript i] to a final pressure P[subscript f], by being placed in…
Commercial concepts for adiabatic compressed air energy storage
Energy Technology Data Exchange (ETDEWEB)
Freund, Sebastian [General Electric Global Research, Garching (Germany); Schainker, Robert [Electric Power Research Institute, Palo Alto, CA (United States); Moreau, Robert [General Electric Oil and Gas, Florence (Italy)
2012-07-01
Adiabatic compressed air energy storage (ACAES) systems offer the potential for efficient large-scale energy storage, almost approaching values typical for pumped hydro. In an ACAES plant, the heat of compression is stored and utilized during the expansion of the air instead of firing natural gas like in commercial CAES. However, no ACAES plants have been commercialized due to challenges with respect to the cost and the heat storage technology. In this study, conducted by EPRI, GE Global Research and GE Oil and Gas, several concepts for ACAES plants are analyzed and their efficiency, complexity and technical risk compared. The components selected for the plants are available either off-the-shelf or near-commercial within a short development time and without the high costs associated with developing a new generation of large custom-made compressors and turbines. The most promising concept for near-term commercialization and low costs turns out to be a two-stage, low-temperature ACAES system. A regenerative (solid) and a recuperative (liquid) thermal storage system have been designed and analyzed for this concept, with the result that the liquid-recuperative system offers a much lower cost and comparable performance. Performance and cost targets for the concepts are 100 MW output per plant for 6 h with a round-trip efficiency above 60% and a capital cost of about $1000/kW. Selections of the turbomachinery for the compression and expansion train from General Electric Oil and Gas are presented for several plant options along with their expansion power range (25..100 MW), round-trip efficiency (66%..70%) and preliminary capital cost estimates (1100..1200 $/kW).
Adiabatic Liquid Piston Compressed Air Energy Storage
Petersen, Tage; Elmegaard, Brian; Pedersen, Allan Schrøder
2013-01-01
This project investigates the potential of a Compressed Air Energy Storage system (CAES system). CAES systems are used to store mechanical energy in the form of compressed air. The systems use electricity to drive the compressor at times of low electricity demand with the purpose of converting the mechanical energy into electricity at times of high electricity demand. Two such systems are currently in operation; one in Germany (Huntorf) and one in the USA (Macintosh, Alabama). In both cases, ...
Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage
International Nuclear Information System (INIS)
Highlights: • The paper presents a thermodynamic analysis of A-CAES using packed bed regenerators. • The packed beds are used to store the compression heat. • A numerical model is developed, validated and used to simulate system operation. • The simulated efficiencies are between 70.5% and 71.1% for continuous operation. • Heat build-up in the beds reduces continuous cycle efficiency slightly. - Abstract: The majority of articles on Adiabatic Compressed Air Energy Storage (A-CAES) so far have focussed on the use of indirect-contact heat exchangers and a thermal fluid in which to store the compression heat. While packed beds have been suggested, a detailed analysis of A-CAES with packed beds is lacking in the available literature. This paper presents such an analysis. We develop a numerical model of an A-CAES system with packed beds and validate it against analytical solutions. Our results suggest that an efficiency in excess of 70% should be achievable, which is higher than many of the previous estimates for A-CAES systems using indirect-contact heat exchangers. We carry out an exergy analysis for a single charge–storage–discharge cycle to see where the main losses are likely to transpire and we find that the main losses occur in the compressors and expanders (accounting for nearly 20% of the work input) rather than in the packed beds. The system is then simulated for continuous cycling and it is found that the build-up of leftover heat from previous cycles in the packed beds results in higher steady state temperature profiles of the packed beds. This leads to a small reduction (<0.5%) in efficiency for continuous operation
Adiabatic compression of elongated field-reversed configurations
International Nuclear Information System (INIS)
The simplest model of plasma dynamics is the adiabatic model. In this model the plasma is assumed to be in MHD equilibrium at each instant of time. The equilibria are connected by the requirement that they all have the same entropy per unit flux, i.e., the equilibria form a sequence generated by adiabatic changes. The standard way of computing such a sequence of equilibria was developed by Grad, but its practical use requires a fairly complicated code. It would be helpful if approximately the same results could be gotten either with a much simpler code or by analytical techniques. A one-dimensional equilibrium code is described and its results are checked against a two-dimensional equilibrium. An even simpler analytic calculation is then presented
Prediction of mean flow data for adiabatic 2-D compressible turbulent boundary layers
Motallebi, F.
1997-01-01
This book presents a method for the prediction of mean flow data (i.e. skin friction, velocity profile and shape parameter) for adiabatic two-dimensional compressible turbulent boundary layers at zero pressure gradient. The transformed law of the wall, law of the lake, the van Driest model for the c
Hot-electron nanoscopy using adiabatic compression of surface plasmons
Giugni, Andrea
2013-10-20
Surface plasmon polaritons are a central concept in nanoplasmonics and have been exploited to develop ultrasensitive chemical detection platforms, as well as imaging and spectroscopic techniques at the nanoscale. Surface plasmons can decay to form highly energetic (or hot) electrons in a process that is usually thought to be parasitic for applications, because it limits the lifetime and propagation length of surface plasmons and therefore has an adverse influence on the functionality of nanoplasmonic devices. Recently, however, it has been shown that hot electrons produced by surface plasmon decay can be harnessed to produce useful work in photodetection, catalysis and solar energy conversion. Nevertheless, the surface-plasmon-to-hot-electron conversion efficiency has been below 1% in all cases. Here we show that adiabatic focusing of surface plasmons on a Schottky diode-terminated tapered tip of nanoscale dimensions allows for a plasmon-to-hot-electron conversion efficiency of ∼30%. We further demonstrate that, with such high efficiency, hot electrons can be used for a new nanoscopy technique based on an atomic force microscopy set-up. We show that this hot-electron nanoscopy preserves the chemical sensitivity of the scanned surface and has a spatial resolution below 50 nm, with margins for improvement.
Large-Strain Time-Temperature Equivalence and Adiabatic Heating of Polyethylene
Energy Technology Data Exchange (ETDEWEB)
Furmanski, Jevan [Los Alamos National Laboratory; Brown, Eric [Los Alamos National Laboratory; Cady, Carl M. [Los Alamos National Laboratory
2012-06-06
Time-temperature equivalence is a well-known phenomenon in time-dependent material response, where rapid events at a moderate temperature are indistinguishable from some occurring at modest rates but elevated temperatures. However, there is as-yet little elucidation of how well this equivalence holds for substantial plastic strains. In this work, we demonstrate time-temperature equivalence over a large range in a previously studied high-density polyethylene formulation (HDPE). At strain-rates exceeding 0.1/s, adiabatic heating confounds the comparison of nominally isothermal material response, apparently violating time-temperature equivalence. Strain-rate jumps can be employed to access the instantaneous true strain rate without heating. Adiabatic heating effects were isolated by comparing a locus of isothermal instantaneous flow stress measurements from strain-rate jumps up to 1/s with the predicted equivalent states at 0.01/s and 0.001/s in compression. Excellent agreement between the isothermal jump condition locus and the quasi-static tests was observed up to 50% strain, yielding one effective isothermal plastic response for each material for a given time-temperature equivalent state. These results imply that time-temperature equivalence can be effectively used to predict the deformation response of polymers during extreme mechanical events (large strain and high strain-rate) from measurements taken at reduced temperatures and nominal strain-rates in the laboratory.
International Nuclear Information System (INIS)
This report examines the concept and the main characteristics of the torroidal magnet in a tokamak with a strong magnetic field and combined adiabatic compression of the plasma pinch for an experiment to achieve the parameter Q = 1
Energy Technology Data Exchange (ETDEWEB)
Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faruso@usc.es; Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)
2005-12-15
Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.
Directory of Open Access Journals (Sweden)
Fuping Yuan
2014-12-01
Full Text Available A series of large-scale molecular dynamics simulations were conducted to investigate the scaling laws and the related atomistic deformation mechanisms of Cu monocrystal samples containing randomly placed nanovoids under adiabatic uniaxial strain compression. At onset of yielding, plastic deformation is accommodated by dislocations emitted from void surfaces as shear loops. The collapse of voids are observed by continuous emissions of dislocations from void surfaces and their interactions with further plastic deformation. The simulation results also suggest that the effect modulus, the yield stress and the energy aborption density of samples under uniaxial strain are linearly proportional to the relative density ρ. Moreover, the yield stress, the average flow stress and the energy aborption density of samples with the same relative density show a strong dependence on the void diameter d, expressed by exponential relations with decay coefficients much higher than -1/2. The corresponding atomistic mechanisms for scaling laws of the relative density and the void diameter were also presented. The present results should provide insights for understanding deformation mechanisms of nanoporous metals under extreme conditions.
Ensslin, T A
2001-01-01
We give for a plasma with a history of several expansion and contraction phases an analytical model of the evolution of a contained relativistic electron population under synchrotron, inverse Compton and adiabatic energy losses or gains. This is applied to different scenarios for evolution of radio plasma inside the cocoons of radio galaxies, after the activity of the central engine has ceased. It is demonstrated that fossil radio plasma with an age of even up to 2 Gyr can be revived by compression in a shock wave of large-scale structure formation, caused during the merging events of galaxy clusters, or by the accretion onto galaxy clusters. We argue, that this is a highly plausible explanation for the observed cluster radio relics, which are the regions of diffuse radio emission found in clusters of galaxies, without any likely parent radio galaxy seen nearby. An implication of this model is the existence of a population of diffuse, ultra-steep spectrum, very low frequency radio sources located inside and p...
Energy Technology Data Exchange (ETDEWEB)
MacPhee, A. G.; Peterson, J. L.; Casey, D. T.; Clark, D. S.; Haan, S. W.; Jones, O. S.; Landen, O. L.; Milovich, J. L.; Robey, H. F.; Smalyuk, V. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
2015-08-15
Hydrodynamic instabilities and poor fuel compression are major factors for capsule performance degradation in ignition experiments on the National Ignition Facility. Using a recently developed laser drive profile with a decaying first shock to tune the ablative Richtmyer-Meshkov (ARM) instability and subsequent in-flight Rayleigh-Taylor growth, we have demonstrated reduced growth compared to the standard ignition pulse whilst maintaining conditions for a low fuel adiabat needed for increased compression. Using in-flight x-ray radiography of pre-machined modulations, the first growth measurements using this new ARM-tuned drive have demonstrated instability growth reduction of ∼4× compared to the original design at a convergence ratio of ∼2. Corresponding simulations give a fuel adiabat of ∼1.6, similar to the original goal and consistent with ignition requirements.
MacPhee, A. G.; Peterson, J. L.; Casey, D. T.; Clark, D. S.; Haan, S. W.; Jones, O. S.; Landen, O. L.; Milovich, J. L.; Robey, H. F.; Smalyuk, V. A.
2015-08-01
Hydrodynamic instabilities and poor fuel compression are major factors for capsule performance degradation in ignition experiments on the National Ignition Facility. Using a recently developed laser drive profile with a decaying first shock to tune the ablative Richtmyer-Meshkov (ARM) instability and subsequent in-flight Rayleigh-Taylor growth, we have demonstrated reduced growth compared to the standard ignition pulse whilst maintaining conditions for a low fuel adiabat needed for increased compression. Using in-flight x-ray radiography of pre-machined modulations, the first growth measurements using this new ARM-tuned drive have demonstrated instability growth reduction of ˜4× compared to the original design at a convergence ratio of ˜2. Corresponding simulations give a fuel adiabat of ˜1.6, similar to the original goal and consistent with ignition requirements.
Adiabatic Quasi-Spherical Compressions Driven by Magnetic Pressure for Inertial Confinement Fusion
Energy Technology Data Exchange (ETDEWEB)
NASH,THOMAS J.
2000-11-01
The magnetic implosion of a high-Z quasi-spherical shell filled with DT fuel by the 20-MA Z accelerator can heat the fuel to near-ignition temperature. The attainable implosion velocity on Z, 13-cm/{micro}s, is fast enough that thermal losses from the fuel to the shell are small. The high-Z shell traps radiation losses from the fuel, and the fuel reaches a high enough density to reabsorb the trapped radiation. The implosion is then nearly adiabatic. In this case the temperature of the fuel increases as the square of the convergence. The initial temperature of the fuel is set by the heating of an ion acoustic wave to be about 200-eV after a convergence of 4. To reach the ignition temperature of 5-keV an additional convergence of 5 is required. The implosion dynamics of the quasi-spherical implosion is modeled with the 2-D radiation hydrodynamic code LASNEX. LASNEX shows an 8-mm diameter quasi-spherical tungsten shell on Z driving 6-atmospheres of DT fuel nearly to ignition at 3.5-keV with a convergence of 20. The convergence is limited by mass flow along the surface of the quasi-spherical shell. With a convergence of 20 the final spot size is 400-{micro}m in diameter.
Optimal control of the power adiabatic stroke of an optomechanical heat engine
Bathaee, M.; Bahrampour, A. R.
2016-08-01
We consider the power adiabatic stroke of the Otto optomechanical heat engine introduced in Phys. Rev. Lett. 112, 150602 (2014), 10.1103/PhysRevLett.112.150602. We derive the maximum extractable work of both optomechanical normal modes in the minimum time while the system experiences quantum friction effects. We show that the total work done by the system in the power adiabatic stroke is optimized by a bang-bang control. The time duration of the power adiabatic stroke is of the order of the inverse of the effective optomechanical-coupling coefficient. The optimal phase-space trajectory of the Otto cycle for both optomechanical normal modes is also obtained.
QCD phase diagram : heating or compressing ?
Maire, Antonin
2011-01-01
The sketch tries to address the question of the difference between heating and compressing the baryonic matter in relativistic heavy-ion collisions, i.e. how one can reach in the laboratory "high" temperature at "low" net baryon density (baryon chemical potential) or "low" temperature at "high" net baryon density.
Scaling-up quantum heat engines efficiently via shortcuts to adiabaticity
Beau, M; del Campo, A
2016-01-01
The finite-time operation of a quantum heat engine that uses a single particle as a working medium generally increases the output power at the expense of inducing friction that lowers the cycle efficiency. We propose to scale up a quantum heat engine utilizing a many-particle working medium in combination with the use of shortcuts to adiabaticity to boost the nonadiabatic performance by eliminating quantum friction and reducing the cycle time. To this end, we first analyze the finite-time thermodynamics of a quantum Otto cycle implemented with a quantum fluid confined in a time-dependent harmonic trap. We show that nonadiabatic effects can be controlled and tailored to match the adiabatic performance using a variety of shortcuts to adiabaticity. As a result, the nonadiabatic dynamics of the scaled-up many-particle quantum heat engine exhibits no friction and the cycle can be run at maximum efficiency with a tunable output power. We demonstrate our results with a working medium consisting of particles with inv...
Scaling-Up Quantum Heat Engines Efficiently via Shortcuts to Adiabaticity
Directory of Open Access Journals (Sweden)
Mathieu Beau
2016-04-01
Full Text Available The finite-time operation of a quantum heat engine that uses a single particle as a working medium generally increases the output power at the expense of inducing friction that lowers the cycle efficiency. We propose to scale up a quantum heat engine utilizing a many-particle working medium in combination with the use of shortcuts to adiabaticity to boost the nonadiabatic performance by eliminating quantum friction and reducing the cycle time. To this end, we first analyze the finite-time thermodynamics of a quantum Otto cycle implemented with a quantum fluid confined in a time-dependent harmonic trap. We show that nonadiabatic effects can be controlled and tailored to match the adiabatic performance using a variety of shortcuts to adiabaticity. As a result, the nonadiabatic dynamics of the scaled-up many-particle quantum heat engine exhibits no friction, and the cycle can be run at maximum efficiency with a tunable output power. We demonstrate our results with a working medium consisting of particles with inverse-square pairwise interactions that includes non-interacting and hard-core bosons as limiting cases.
Effect of adiabatic square ribs on natural convection in an asymmetrically heated channel
Abidi-Saad, Aissa; Kadja, Mahfoud; Popa, Catalin; Polidori, Guillaume
2016-06-01
A 2-D numerical simulation is carried out to investigate the effect of two adiabatic square ribs on laminar flow and heat transfer in an asymmetrically heated channel. The two ribs are symmetrically located on each wall, exactly above the heating zone. The computational procedure is made by solving the unsteady bi-dimensional continuity, momentum and energy equations with the finite volume method. The investigations focused more specifically on the influence of ribs sizes on the flow structure and heat transfer enhancement. The results showed that the variation of ribs sizes significantly alters the heat transfer and fluid flow distribution along the channel, especially in the vicinity of protrusions. Also, the results show that streamlines, isotherms, and the number, sizes and formation of vortex structures inside the channel strongly depend on the size of protrusions. The changes in heat transfer parameters have also been presented.
Waste heat recovery from adiabatic diesel engines by exhaust-driven Brayton cycles
Khalifa, H. E.
1983-01-01
An evaluation of Bryton Bottoming Systems (BBS) as waste heat recovery devices for future adiabatic diesel engines in heavy duty trucks is presented. Parametric studies were performed to evaluate the influence of external and internal design parameters on BBS performance. Conceptual design and trade-off studies were undertaken to estimate the optimum configuration, size, and cost of major hardware components. The potential annual fuel savings of long-haul trucks equipped with BBS were estimated. The addition of a BBS to a turbocharged, nonaftercooled adiabatic engine would improve fuel economy by as much as 12%. In comparison with an aftercooled, turbocompound engine, the BBS-equipped turbocharged engine would offer a 4.4% fuel economy advantage. If installed in tandem with an aftercooled turbocompound engine, the BBS could effect a 7.2% fuel economy improvement. The cost of a mass-produced 38 Bhp BBS is estimated at about $6460 or 170/Bhp. Technical and economic barriers that hinder the commercial introduction of bottoming systems were identified. Related studies in the area of waste heat recovery from adiabatic diesel engines and NASA-CR-168255 (Steam Rankine) and CR-168256 (Organic Rankine).
Energy Technology Data Exchange (ETDEWEB)
Bailey, M.M.
1985-07-01
Three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced ''adiabatic'' diesel engines. The power cycle alternatives considered were steam Rankine, organic Rankine with RC-1 as the working fluid, and variations of an air Brayton cycle. The comparison was made in terms of fuel economy and economic payback potential for heavy-duty trucks operating in line-haul service. The results indicate that, in terms of engine rated specific fuel consumption, a diesel/alternative-power-cycle engine offers a significant improvement over the turbocompound diesel used as the baseline for comparison. The maximum improvement resulted from the use of a Rankine cycle heat-recovery system in series with turbocompounding. The air Brayton cycle alternatives studied, which included both simple-cycle and compression-intercooled configurations, were less effective and provided about half the fuel consumption improvement of the Rankine cycle alternatives under the same conditions. Capital and maintenance cost estimates were also developed for each of the heat-recovery power cycle systems. These costs were integrated with the fuel savings to identify the time required for net annual savings to pay back the initial capital investment. The sensitivity of capital payback time to arbitrary increases in fuel price, not accompanied by corresponding hardware cost inflation, was also examined. The results indicate that a fuel price increase is required for the alternative power cycles to pay back capital within an acceptable time period.
Bailey, M. M.
1985-01-01
Three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced adiabatic diesel engines. The power cycle alternatives considered were steam Rankine, organic Rankine with RC-1 as the working fluid, and variations of an air Brayton cycle. The comparison was made in terms of fuel economy and economic payback potential for heavy-duty trucks operating in line-haul service. The results indicate that, in terms of engine rated specific fuel consumption, a diesel/alternative-power-cycle engine offers a significant improvement over the turbocompound diesel used as the baseline for comparison. The maximum imporvement resulted from the use of a Rankine cycle heat-recovery system in series with turbocompounding. The air Brayton cycle alternatives studied, which included both simple-cycle and compression-intercooled configurations, were less effective and provided about half the fuel consumption improvement of the Rankine cycle alternatives under the same conditions. Capital and maintenance cost estimates were also developed for each of the heat-recovery power cycle systems. These costs were integrated with the fuel savings to identify the time required for net annual savings to pay back the initial capital investment. The sensitivity of capital payback time to arbitrary increases in fuel price, not accompanied by corresponding hardware cost inflation, was also examined. The results indicate that a fuel price increase is required for the alternative power cycles to pay back capital within an acceptable time period.
Directory of Open Access Journals (Sweden)
Fuxi Shi
2014-01-01
Full Text Available The molecular compressibility, which is a macroscopic quantity to reveal the microcompressibility by additivity of molecular constitutions, is considered as a fixed value for specific organic liquids. In this study, we introduced two calculated expressions of molecular adiabatic compressibility to demonstrate its pressure and temperature dependency. The first one was developed from Wada’s constant expression based on experimental data of density and sound velocity. Secondly, by introducing the 2D fitting expressions and their partial derivative of pressure and temperature, molecular compressibility dependency was analyzed further, and a 3D fitting expression was obtained from the calculated data of the first one. The third was derived with introducing the pressure and temperature correction factors based on analogy to Lennard-Jones potential function and energy equipartition theorem. In wide range of temperatures (293
Ensslin, Torsten A.; Gopal-Krishna
2000-01-01
We give for a plasma with a history of several expansion and contraction phases an analytical model of the evolution of a contained relativistic electron population under synchrotron, inverse Compton and adiabatic energy losses or gains. This is applied to different scenarios for evolution of radio plasma inside the cocoons of radio galaxies, after the activity of the central engine has ceased. It is demonstrated that fossil radio plasma with an age of even up to 2 Gyr can be revived by compr...
International Nuclear Information System (INIS)
Most modern refrigerators incorporate heat transfer between the refrigerant in a capillary tube and the refrigerant in a suction line. This heat transfer is achieved by a non-adiabatic capillary tube called a capillary tube-suction line heat exchanger and is supposed to improve the performance of the small vapor compression refrigeration cycle by removing some enthalpy of the refrigerant at the evaporator entrance. To investigate the effects of this heat transfer on the refrigeration cycle, a computer program was developed based on conservation equations of mass, momentum, and energy. The non-adiabatic capillary tube model is based on a homogeneous two-phase flow model. The simulation results show that both the location and length of the heat exchange section influence the coefficient of performance (COP) as well as the cooling capacity. It is noteworthy that the influence was not monotonic; that is, the performance may be deteriorated under certain conditions
Energy Technology Data Exchange (ETDEWEB)
Marquardt, Roland; Moser, Peter [RWE Power AG, Essen (Germany). Forschung und Entwicklung, Neue Technologien; Hoffmann, Stephanie [GE Global Research Europe, Garching (Germany); Pazzi, Simone [GE Infrastructure, Oil and Gas, Firenze (Italy); Klafki, Michael [ESK GmbH (RWE Group), Freiberg (Germany); Zunft, Stefan [Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), Stuttgart (Germany). Inst. fuer Technische Thermodynamik
2008-07-01
An expansion of CO{sub 2}-neutral energy supply is in the focus of European and national environmental policy and will be crucially supported by offshore wind power generation in future. Grid-compatible integration of these fluctuating electricity quantities will - in the medium term already - require substantial adjustments of the German grid and power plant system in order to cope with the upcoming new boundary conditions. The development of new technologies for large-scale electricity storage is a key element in future flexible European electricity transmission systems. Electricity storage in Adiabatic CAES power plants offers the prospect of making a substantial contribution to reach this goal. This concept allows efficient, local zero-emission electricity storage on the basis of compressed air in underground caverns. The compression and expansion of air in turbomachinery help to balance power generation peaks that are not demand-driven on the one hand and consumption-induced load peaks on the other. Before this concept can be implemented, however, several technical problems must be solved and technical development work done, especially in the field of turbomachinery and the required heat storage device. This paper outlines the technical possibilities and the need for development. Ongoing development activities are described and first interim results presented. (orig.)
Waste heat recovery from adiabatic diesel engines by exhaust-driven Brayton cycles
Energy Technology Data Exchange (ETDEWEB)
Khalifa, H.E.
1983-12-01
This report presents an evaluation of Brayton Bottoming Systems (BBS) as waste heat recovery devices for future adiabatic diesel engines in heavy duty trucks. Parametric studies were performed to evaluate the influence of external and internal design parameters on BBS performance. Conceptual design and trade-off studies were undertaken to estimate the optimum configuration, size, and cost of major hardware components. The potential annual fuel savings of long-haul trucks equipped with BBS were estimated. The addition of a BBS to a turbocharged, nonaftercooled adiabatic engine would improve fuel economy by as much as 12%. In comparison with an aftercooled, turbocompound engine, the BBS-equipped turbocharged engine would offer a 4.4% fuel economy advantage. It is also shown that, if installed in tandem with an aftercooled turbocompound engine, the BBS could effect a 7.2% fuel economy improvement. The cost of a mass-produced 38 Bhp BBS is estimated at about $6460 or $170/Bhp. Technical and economic barriers that would hinder the commercial introduction of bottoming systems were identified.
Non Adiabatic Centrifugal Compressor Gas Dynamic Performance Definition
Soldatova, Kristina
2014-01-01
Most centrifugal compressors operate in conditions with negligible heat transfer (adiabatic compression). Their plant tests conditions are similar or close to adiabatic conditions. Test regulations establish measures to diminish influence of a heat transfer “compressor body – atmospheric air” to an exit temperature. Therefore a temperature rise in a compressor is used to calculate a work input coefficient and efficiency. Unlike it high pressure centrifugal compressors of gas turbines and supe...
Energy Technology Data Exchange (ETDEWEB)
Milovich, J. L., E-mail: milovich1@llnl.gov; Robey, H. F.; Clark, D. S.; Baker, K. L.; Casey, D. T.; Cerjan, C.; Field, J.; MacPhee, A. G.; Pak, A.; Patel, P. K.; Peterson, J. L.; Smalyuk, V. A.; Weber, C. R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
2015-12-15
Experimental results from indirectly driven ignition implosions during the National Ignition Campaign (NIC) [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] achieved a record compression of the central deuterium-tritium fuel layer with measured areal densities up to 1.2 g/cm{sup 2}, but with significantly lower total neutron yields (between 1.5 × 10{sup 14} and 5.5 × 10{sup 14}) than predicted, approximately 10% of the 2D simulated yield. An order of magnitude improvement in the neutron yield was subsequently obtained in the “high-foot” experiments [O. A. Hurricane et al., Nature 506, 343 (2014)]. However, this yield was obtained at the expense of fuel compression due to deliberately higher fuel adiabat. In this paper, the design of an adiabat-shaped implosion is presented, in which the laser pulse is tailored to achieve similar resistance to ablation-front instability growth, but with a low fuel adiabat to achieve high compression. Comparison with measured performance shows a factor of 3–10× improvement in the neutron yield (>40% of predicted simulated yield) over similar NIC implosions, while maintaining a reasonable fuel compression of >1 g/cm{sup 2}. Extension of these designs to higher laser power and energy is discussed to further explore the trade-off between increased implosion velocity and the deleterious effects of hydrodynamic instabilities.
Milovich, J. L.; Robey, H. F.; Clark, D. S.; Baker, K. L.; Casey, D. T.; Cerjan, C.; Field, J.; MacPhee, A. G.; Pak, A.; Patel, P. K.; Peterson, J. L.; Smalyuk, V. A.; Weber, C. R.
2015-12-01
Experimental results from indirectly driven ignition implosions during the National Ignition Campaign (NIC) [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] achieved a record compression of the central deuterium-tritium fuel layer with measured areal densities up to 1.2 g/cm2, but with significantly lower total neutron yields (between 1.5 × 1014 and 5.5 × 1014) than predicted, approximately 10% of the 2D simulated yield. An order of magnitude improvement in the neutron yield was subsequently obtained in the "high-foot" experiments [O. A. Hurricane et al., Nature 506, 343 (2014)]. However, this yield was obtained at the expense of fuel compression due to deliberately higher fuel adiabat. In this paper, the design of an adiabat-shaped implosion is presented, in which the laser pulse is tailored to achieve similar resistance to ablation-front instability growth, but with a low fuel adiabat to achieve high compression. Comparison with measured performance shows a factor of 3-10× improvement in the neutron yield (>40% of predicted simulated yield) over similar NIC implosions, while maintaining a reasonable fuel compression of >1 g/cm2. Extension of these designs to higher laser power and energy is discussed to further explore the trade-off between increased implosion velocity and the deleterious effects of hydrodynamic instabilities.
Shouman, A. R.; Garcia, C. E.
1971-01-01
An analytical solution for the compressible one-dimensional flow in convergent and divergent ducts with friction is obtained. It is found that a nondimensional parameter, N, can be formed using the friction factor, duct half-angle and the ratio of specific heats of the gas. Seven flow regimes are describable with the solution, based on certain bounds on the magnitude of N. The regimes are discussed and corollary data are presented graphically.
Leinonen, Risto; Asikainen, Mervi A.; Hirvonen, Pekka E.
2012-12-01
This study focuses on second-year university students' explanations and reasoning related to adiabatic compression of an ideal gas. The phenomenon was new to the students, but it was one which they should have been capable of explaining using their previous upper secondary school knowledge. The students' explanations and reasoning were investigated with the aid of paper and pencil tests ( n = 86) and semi-structured interviews ( n = 5) at the start of a thermal physics course at the University of Eastern Finland. The paper and pencil test revealed that the students had difficulties in applying content taught during earlier education in a new context: only a few of them were able to produce a correct explanation for the phenomenon. A majority of the students used either explanations with invalid but physically correct models, such as the ideal gas law or a microscopic model, or erroneous dependencies between quantities. The results also indicated that students had problems in seeing deficiencies or inconsistencies in their reasoning, in both test and interview situations. We suggest in our conclusion that the contents of upper secondary school thermal physics courses should be carefully examined to locate the best emphases for different laws, principles, concepts, and models. In particular, the limitations of models should be made explicit in teaching and students should be guided towards critical scientific thinking, including metaconceptual awareness.
Thermal Behavior, Specific Heat Capacity and Adiabatic Time-to-explosion of GDN
Institute of Scientific and Technical Information of China (English)
YANG Xing-kun; XU Kang-zhen; ZHAO Feng-qi; YANG Xin; WANG Han; SONG Ji-rong; WANG Yao-yu
2009-01-01
A new compound, [(NH2)2C=NH2]+N(NO2)2-(GDN), was prepared by mixing ammonium dinitramide (ADN) and guanidine hydrochloride in water. The thermal behavior of GDN was studied under the non-isothermal conditions with DSC and TG/DTG methods. The apparent activation energy(E) and pre-exponential constant(A) of the exothermic decomposition stage of GDN were 118.75 kJ/mol and 1010.86 s-1, respectively. The critical temperature of the thermal explosion(Tb) of GDN was 164.09 ℃. The specific heat capacity of GDN was determined with the Micro-DSC method and the theoretical calculation method, and the standard molar specific heat capacity was 234.76J·mol-1·K-1 at 298.15K.The adiabatic time-to-explosion of GDN was also calculated to be a certain value between 404.80 and 454.95 s.
International Nuclear Information System (INIS)
The numerical works presented in this paper belong to the IN-CORE (Instrumentation for Nuclear radiations and Calorimetry Online in REactor) research program. Its scientific aim is to create a new device dedicated to the online simultaneously measurements of nuclear conditions inside experimental channels of the Jules Horowitz Reactor (JHR) by coupling different sensors. This paper studies a specific one: a radiometric calorimeter used to in pile nuclear heating measurements. Numerical simulations on heat transfers taking place into this sensor under radioactive and nonradioactive conditions are carried out. The influence of the geometrical dimensions and of the energy deposit on the heat flux density, on the sensor sensitivity and on the maximum temperature is discussed. (author)
Directory of Open Access Journals (Sweden)
S.V. Chuduk
2011-01-01
Full Text Available In article the review of the information on possibilities of use of recuperators of heat is presented for the warm period of year for air-conditioning system. Aim of heat exchanger work in frost-free season is indirect cooling of incoming air before its input into maintainable premises. It is possible if exhaust air is cooled before its input into heat exchanger . In the article the operational principle of air conditioning system with using of adiabatic air cooling is considered. The data concerned system functioning depending on parameters of microclimate in maintainable premises are given.
Coabsorbent and thermal recovery compression heat pumping technologies
Staicovici, Mihail-Dan
2014-01-01
This book introduces two of the most exciting heat pumping technologies, the coabsorbent and the thermal recovery (mechanical vapor) compression, characterized by a high potential in primary energy savings and environmental protection. New cycles with potential applications of nontruncated, truncated, hybrid truncated, and multi-effect coabsorbent types are introduced in this work. Thermal-to-work recovery compression (TWRC) is the first of two particular methods explored here, including how superheat is converted into work, which diminishes the compressor work input. In the second method, thermal-to-thermal recovery compression (TTRC), the superheat is converted into useful cooling and/or heating, and added to the cycle output effect via the coabsorbent technology. These and other methods of discharge gas superheat recovery are analyzed for single-, two-, three-, and multi-stage compression cooling and heating, ammonia and ammonia-water cycles, and the effectiveness results are given. The author presen...
Heat recovery by means of innovative, already successfully tested absorption compression heat pumps
Energy Technology Data Exchange (ETDEWEB)
Mucic, V. [Schmeink und Cofreth GmbH and Co. KG, Bocholt (Germany)
1996-07-01
First the paper shows the thermodynamical advantages of mixtures compared to single substances as working fluids for compression heat pumps. It is especially the ammonia-water mixture which above all other known mixtures has the best thermodynamical characteristics as a working medium for high-temperature heat pumps used for industrial heat recovery. Then it is shown that the industrial waste heat which at present is uselessly delivered to the environment can be economically recovered by means of absorption compression heat pumps observing certain requirements specified in detail in the paper. (orig.)
Mahdavi, Mahboobe; Tiari, Saeed; Qiu, Songgang
2015-11-01
Latent heat thermal energy storage systems benefits from high energy density and isothermal storing process. However, the low thermal conductivity of the phase change material leads to prolong the melting or solidification time. Using a passive device such as heat pipes is required to enhance the heat transfer and to improve the efficiency of the system. In the present work, the performance of a heat pipe network specifically designed for a thermal energy storage system is studied numerically. The network includes a primary heat pipe, which transfers heat received from solar receiver to the heat engine. The excess heat is simultaneously delivered to charge the phase change material via secondary heat pipes. The primary heat pipe composed of a disk shape evaporator, an adiabatic section and a disk shape condenser. The adiabatic section can be either located at the center or positioned outward to the surrounding of the container. Here, the effect of adiabatic section position on thermal performance of the system is investigated. It was concluded that displacing the adiabatic section outwards dramatically increases the average temperatures of the condensers and reduces the thermal resistance of heat pipes.
Loverude, Michael E.; Kautz, Christian H.; Heron, Paula R. L.
2002-01-01
Reports on an investigation of student understanding of the first law of thermodynamics. Involves students from a first-year university physics course and a second-year thermal physics course. Focuses on the ability of students to relate the first law to the adiabatic physics course. Discusses implications for thermal physics and mechanics…
International Nuclear Information System (INIS)
This study presents an application of the artificial neural network (ANN) model using the back propagation (BP) learning algorithm to predict the performance (suction line outlet temperature and mass flow rate) of a non-adiabatic capillary tube suction line heat exchanger, basically used as a throttling device in small household refrigeration systems. Comparative studies were made by using an ANN model, experimental results and correlations to predict the performance. These studies showed that the proposed approach could successfully be used for performance prediction for the exchanger
Conjugate Compressible Fluid Flow and Heat Transfer in Ducts
Cross, M. F.
2011-01-01
A computational approach to modeling transient, compressible fluid flow with heat transfer in long, narrow ducts is presented. The primary application of the model is for analyzing fluid flow and heat transfer in solid propellant rocket motor nozzle joints during motor start-up, but the approach is relevant to a wide range of analyses involving rapid pressurization and filling of ducts. Fluid flow is modeled through solution of the spatially one-dimensional, transient Euler equations. Source terms are included in the governing equations to account for the effects of wall friction and heat transfer. The equation solver is fully-implicit, thus providing greater flexibility than an explicit solver. This approach allows for resolution of pressure wave effects on the flow as well as for fast calculation of the steady-state solution when a quasi-steady approach is sufficient. Solution of the one-dimensional Euler equations with source terms significantly reduces computational run times compared to general purpose computational fluid dynamics packages solving the Navier-Stokes equations with resolved boundary layers. In addition, conjugate heat transfer is more readily implemented using the approach described in this paper than with most general purpose computational fluid dynamics packages. The compressible flow code has been integrated with a transient heat transfer solver to analyze heat transfer between the fluid and surrounding structure. Conjugate fluid flow and heat transfer solutions are presented. The author is unaware of any previous work available in the open literature which uses the same approach described in this paper.
Vapor-Compression Heat Pumps for Operation Aboard Spacecraft
Ruemmele, Warren; Ungar, Eugene; Cornwell, John
2006-01-01
Vapor-compression heat pumps (including both refrigerators and heat pumps) of a proposed type would be capable of operating in microgravity and would be safe to use in enclosed environments like those of spacecraft. The designs of these pumps would incorporate modifications of, and additions to, vapor-compression cycles of heat pumps now used in normal Earth gravitation, in order to ensure efficiency and reliability during all phases of operation, including startup, shutdown, nominal continuous operation, and peak operation. Features of such a design might include any or all of the following: (1) Configuring the compressor, condenser, evaporator, valves, capillary tubes (if any), and controls to function in microgravitation; (2) Selection of a working fluid that satisfies thermodynamic requirements and is safe to use in a closed crew compartment; (3) Incorporation of a solenoid valve and/or a check valve to prevent influx of liquid to the compressor upon startup (such influx could damage the compressor); (4) Use of a diode heat pipe between the cold volume and the evaporator to limit the influx of liquid to the compressor upon startup; and (5) Use of a heated block to vaporize any liquid that arrives at the compressor inlet.
Modeling and integration of a heat storage tank in a compressed air electricity storage process
International Nuclear Information System (INIS)
Highlights: • Large-scale heat storage tank behavior is explored with a two dimensional model. • Thermal storage tank efficiencies are estimated thanks to dimensionless numbers. • Abacuses of the tank efficiency are provided. • The link between tank efficiency and A-CAES global efficiency is generated. - Abstract: In an adiabatic compressed air energy storage process (A-CAES), heat storage tank operation is a key factor that determines the overall energy performance of the process. To highlight energy issues linked to a correct tank design in the specific case of an A-CAES system, a two-dimensional thermal numerical model was developed. Thermal efficiencies of the tank are presented with abacus defined from the four dimensionless numbers defining the thermal behavior of the reservoir. Cycling effects are explored with a realistic case study corresponding to an A-CAES system design to deliver an electrical power of 250 MWel for 4 h, the daily peak demand. Extended beyond the thermal reservoir, A-CAES thermodynamic analysis combined with the dynamic simulation makes it possible to generate a direct quantitative link between reservoir sizing and A-CAES global efficiency
Introduction to compressible fluid flow
Oosthuizen, Patrick H
2013-01-01
IntroductionThe Equations of Steady One-Dimensional Compressible FlowSome Fundamental Aspects of Compressible FlowOne-Dimensional Isentropic FlowNormal Shock WavesOblique Shock WavesExpansion Waves - Prandtl-Meyer FlowVariable Area FlowsAdiabatic Flow with FrictionFlow with Heat TransferLinearized Analysis of Two-Dimensional Compressible FlowsHypersonic and High-Temperature FlowsHigh-Temperature Gas EffectsLow-Density FlowsBibliographyAppendices
Development of a vapor compression heat pump for space use
Berner, F.; Savage, C. J.
1981-06-01
A heat pump is presently developed for use in Spacelab as a stand-alone refrigeration unit as well as within a fluid loop system. It is expected to feature a high coefficient of performance because its power requirement is minimized through continuous adjustment of two operating parameters of its vapor compression cycle, i.e., evaporator pressure and compressor speed, to the instantaneous cooling requirements and heat rejection conditions. The heat pump system will achieve the highest possible cooling rate as long as the temperature of the payload to be cooled is significantly above the desired level, and it will minimize the difference between actual and set heat source temperature when this difference has become small. The most complicated component of the heat pump is the reciprocating vapor compressor. This component's main features are described and its experimentally determined performance parameters are given. Based on these parameters, operating maps, showing achievable heat source temperatures and cooling rates with curves of constant power consumption included, are presented for different temperatures of the fluid to which the heat is rejected.
Natural convection in an adiabatic vertical channel due to a dissipated heat element
International Nuclear Information System (INIS)
An experimental study was perfomed on natural convection heat transfer to air in a vertical channel due to an isothermal heated element attached in one of the walls of the channel. The heated element dissipates heat due to the Joule effect. To determine the heat transfer coefficient, it is necessary to evaluate the heat transferred to air by natural convenction alone. Hence, the heat lost by the element due to conduction and radiation is evaluated in order to correct the measured heat transfer. The natural-convenction heat transfer coefficient is a function of the following parameters: the temperature difference between the element and the ambient air, the position of the element in the channel, and the channel spacing. An optimal value of the channel spacing, when the heat transfer coefficient attains its maximum value, was observed for each of the temperature difference investigated. These maximum values may be up to 25% higher than the value for the case of infinite spacing. Comparisons are made with results available in the literature for similar configurations, and the values found in this work are higher. (author)
Institute of Scientific and Technical Information of China (English)
NAN, Zhaodong; ZHANG, Pingping; YU, Aijun; WEI, Chengzhen; SHI, Quan; TAN, Zhicheng
2009-01-01
A novel and facile method for preparation of stable nanofluid is introduced, in which FeCl3·6H2O and urea were used as reactants without any surfactants. The obtained solid sample was proved to be β-FeOOH by XRD technol- ogy and spindle-shaped by TEM technology. The coexisting NH3 molecules may be the main reason for the stable nanofluid. The weak bonding between nitrogen and iron atoms would be formed. The investigation on the excess heat capacity of the obtained nanofluid sustains this opinion. The heat capacities of the obtained β-FeOOH particles and the nanofluid were determined by an adiabatic calorimeter. And these obtained results will help the applications of β-FeOOH and the nanofluid to industry, and the establishment of the model of thermal conductivity of nanofluid. The thermodynamic properties of the obtained β-FeOOH particles and the nanofluid were calculated based on the obtained functions of heat capacity with respective to thermodynamic temperature and the relationships between the thermodynamic properties.
Experimental Research on Heat Transfer Characteristics of CuO Nanofluid in Adiabatic Condition
Directory of Open Access Journals (Sweden)
Yu Guangbin
2016-01-01
Full Text Available The laminar convective heat transfer behavior of CuO nanoparticle dispersions in glycol with the average particle sizes (about 70 nm was investigated experimentally in a flow loop with constant heat flux. To enhance heat exchange under high temperature condition and get the more accurate data, we try to improve the traditional experimental apparatus which is used to test nanofluid heat transfer characteristics. In the experiment five different nanoparticle concentrations (0.25%, 0.50%, 0.80%, 1.20%, and 1.50% were investigated in a flow loop with constant heat flux. The experimental results show that the heat transfer coefficient of nanofluid becomes higher than that of pure fluid at the same Reynolds number and increased with the increasing of the mass fraction of CuO nanoparticles. Results also indicate that at very low volume concentrations nanofluid has no major impact on heat transfer parameters and the pressure of nanofluids increased by the mass fraction increase.
Energy Technology Data Exchange (ETDEWEB)
Tiruselvam, R.; Raghavan, Vijay R. [Universiti Teknologi PETRONAS, Faculty of Mechanical Engineering, Tronoh (Malaysia)
2012-04-15
The study is conducted to evaluate the flow characteristics in a double tube heat exchanger using two new and versatile enhancement configurations. The novelty is that they are usable in single phase forced convection, evaporation and condensation. Correlations are proposed for flow development length and friction factor for use in predicting fluid pumping power in thermal equipment as well as in subsequent heat transfer characterization of the surface. (orig.)
Erickson, Lisa R.; Ungar, Eugene K.
2013-01-01
Maximizing the reuse of wastewater while minimizing the use of consumables is critical in long duration space exploration. One of the more promising methods of reclaiming urine is the distillation/condensation process used in the cascade distillation system (CDS). This system accepts a mixture of urine and toxic stabilizing agents, heats it to vaporize the water and condenses and cools the resulting water vapor. The CDS wastewater flow requires heating and its condensate flow requires cooling. Performing the heating and cooling processes separately requires two separate units, each of which would require large amounts of electrical power. By heating the wastewater and cooling the condensate in a single heat pump unit, mass, volume, and power efficiencies can be obtained. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump performance tests are provided. A summary is provided of the heat pump mass, volume and power trades and a selection recommendation is made.
Bartlett, J.; Hardy, G.; Hepburn, I. D.
2015-12-01
The performance of a fast thermal response miniature Adiabatic Demagnetisation Refrigerator (ADR) is presented. The miniature ADR is comprised of a fast thermal response Chromium Potassium Alum (CPA) salt pill, two superconducting magnets and unconventionally, a single crystal tungsten magnetoresistive (MR) heat switch. The development of this ADR is a result of the ongoing development of a continuously operating millikelvin cryocooler (mKCC), which will use only magnetoresistive heat switches. The design and performance of the MR heat switch developed for the mKCC and used in the miniature ADR is presented in this paper; the heat switch has a measured Residual Resistivity Ratio of 32,000 ± 3000 and an estimated switching ratio (on thermal conductivity divided by the off thermal conductivity) of 15,200 at 3.6 K and 38,800 at 0.2 K when using a 3 T magnetic field. The performance of the miniature ADR operating from a 3.6 K bath is presented, demonstrating that a complete cycle (magnetisation, cooling to the bath and demagnetisation) can be accomplished in 82 s. A magnet current step test, conducted when the ADR is cold and fully demagnetised, has shown the thermal response of the ADR to be sub-second. The measured hold times of the ADR with just parasitic heat load are given, ranging from 3 min at 0.2 K with 13.14 μW of parasitics, to 924 min at 3 K with 4.55 μW of parasitics. The cooling power has been measured for operating temperatures in the range 0.25-3 K by applying an additional heat load to the ADR via a heater, in order to reduce the hold time to 3 min (i.e. approximately double the recycle time); the maximum cooling power of the miniature ADR (in addition to parasitic load) when operating at 250 mK is 20 μW, which increases to 45 μW at 300 mK and continues to increase linearly to nearly 1.1 mW at 3 K. To conclude, the predicted performance of a tandem continuous ADR utilising two of the miniature ADRs is presented.
Compressible Turbulent Boundary Layers on a Strongly Heated Wall
Institute of Scientific and Technical Information of China (English)
无
1993-01-01
This paper concerns the theoretical and experimental modelling of the flat wall,highly heated,compressible turbulent boundary layer.Its final objective is to develop a numerical Navier-Stokes solver and to conclude on its capability to correctly represent complex aerothermic viscous flows near the wall.The paper presents a constructed numerical method with particular attention given to the turbulence modelling at low Reynolds number and comparisons with supersonic and transonic experimental data.For the transonic experiment,very high wall temperature(Tw=1100K)is realized.The method of this difficult experimental set up is discussed.The comparison between experimental and computational data conducts to the first conclusion and gives some indications for the future work.
An isentropic compression-heated Ludweig tube transient wind tunnel
Magari, Patrick J.; Lagraff, John E.
1991-01-01
Theoretical development and experimental results show that the Ludweig tube with isentropic heating (LICH) transient wind tunnel described is a viable means of producing flow conditions that are suitable for a variety of experimental investigations. A complete analysis of the wave dynamics of the pump tube compression process is presented. The LICH tube operating conditions are very steady and run times are greater than those of other types of transient facilities such as shock tubes and gas tunnels. This facility is well suited for producing flow conditions that are dynamically similar to those found in a gas turbine, i.e., transonic Mach number, gas-to-wall temperature ratios of about 1.5, and Reynolds numbers greater than 10 to the 6th.
DEFF Research Database (Denmark)
Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix;
2014-01-01
compression heat pump with natural working fluids. This shows that the HACHP increases the temperature lifts and heat supply temperatures that are feasible to produce with a heat pump. The HACHP is shown to be capable of delivering heat supply temperatures as high as 140 XC and temperature lifts up to 60 K...
Energy Technology Data Exchange (ETDEWEB)
Mataya, M.C.; Sackschewsky, V.E.
1993-05-01
Temperature change from conversion of deformation to internal heat, and its effect on stress-strain behavior of alloy 304L was investigated by initially isothermal (temperature of specimen, compression dies, environment equilibrated at initiation of test) uniaxial compression. Strain rate was varied 0.01 s{sup {minus}1} to 1 s{sup {minus}1} (thermal state of specimen varied from nearly isothermal to nearly adiabatic). Specimens were deformed at 750 to 1150 to a strain of 1. Change in temperature with strain was calculated via finite element analysis from measured stress-strain data and predictions were confirmed with thermocouples to verify the model. Temperature increased nearly linearly at the highest strain rate, consistent with temperature rise being a linear function of strain (adiabatic). As strain rate was lowered, heat transfer from superheated specimen to cooler dies caused sample temperature to increase and then decrease with strain as the sample thinned and specimen-die contact area increased. As-measured stress was corrected. Resulting isothermal flow curves were compared to predictions of a simplified method suggested by Thomas and Shrinivasan and differences are discussed. Strain rate sensitivity, activation energy for deformation, and flow curve peak associated with onset of dynamic recrystallization were determined from both as-measured and isothermal stress-strain data and found to vary widely. The impact of utilizing as-measured stress-strain data, not corrected for internal heating, on results of a number of published investigations is discussed.
Reattachment heating upstream of short compression ramps in hypersonic flow
Estruch-Samper, David
2016-05-01
Hypersonic shock-wave/boundary-layer interactions with separation induce unsteady thermal loads of particularly high intensity in flow reattachment regions. Building on earlier semi-empirical correlations, the maximum heat transfer rates upstream of short compression ramp obstacles of angles 15° ⩽ θ ⩽ 135° are here discretised based on time-dependent experimental measurements to develop insight into their transient nature (Me = 8.2-12.3, Re_h= 0.17× 105-0.47× 105). Interactions with an incoming laminar boundary layer experience transition at separation, with heat transfer oscillating between laminar and turbulent levels exceeding slightly those in fully turbulent interactions. Peak heat transfer rates are strongly influenced by the stagnation of the flow upon reattachment close ahead of obstacles and increase with ramp angle all the way up to θ =135°, whereby rates well over two orders of magnitude above the undisturbed laminar levels are intermittently measured (q'_max>10^2q_{u,L}). Bearing in mind the varying degrees of strength in the competing effect between the inviscid and viscous terms—namely the square of the hypersonic similarity parameter (Mθ )^2 for strong interactions and the viscous interaction parameter bar{χ } (primarily a function of Re and M)—the two physical factors that appear to most globally encompass the effects of peak heating for blunt ramps (θ ⩾ 45°) are deflection angle and stagnation heat transfer, so that this may be fundamentally expressed as q'_max∝ {q_{o,2D}} θ ^2 with further parameters in turn influencing the interaction to a lesser extent. The dominant effect of deflection angle is restricted to short obstacle heights, where the rapid expansion at the top edge of the obstacle influences the relaxation region just downstream of reattachment and leads to an upstream displacement of the separation front. The extreme heating rates result from the strengthening of the reattaching shear layer with the increase in
International Nuclear Information System (INIS)
In fire engineering analysis, one of the open problem is the transfer of thermal parameters obtained by fire CFD model to FEM models for structural analysis. In this study the new useful concept of “Adiabatic Surface Temperature” or more commonly known as AST, introduced by Wickström, is investigated. The adiabatic surface temperature offers the opportunity to transfer both thermal information of the gas and the net heat flux to the solid phase model, obtained by CFD analysis. In this study two CFD analyses are carried out in order to evaluate the effect of emissivity and of convective heat transfer coefficient to determine the AST. First one CFD analysis simulating a fire scenario, “conjugate heat transfer”, with a square steel beam exposed to hot surface is carried out to calculate AST, heat convective coefficient and temperature field in the beam. Second one, a conductive analysis is carried out on “standalone beam” imposing a third type boundary condition on its boundaries assuming the AST, evaluated in the conjugate analysis, as external temperature. Different heat convective coefficients are imposed on the beam walls. The comparison between results obtained by means of the two proposed analyses shows the use of AST as transfer thermal parameter between CFD (Computational Fluid Dynamic) and FEM (Finite Element Method) models is appropriate when the convective heat transfer coefficient is properly evaluated. -- Highlights: ► An open problem is to transfer parameters obtained by thermal to structural models. ► The useful concept of “Adiabatic Surface Temperature” (AST) is investigated. ► The AST use is right for properly evaluated convective heat transfer coefficient
AN EXPERIMENTAL STUDY ON A VAPOR COMPRESSION REFRIGERATION CYCLE BY ADDING INTERNAL HEAT EXCHANGER
Muhammad Asmail Eleiwi
2013-01-01
Thispaper presents practical study to improve the indication COP of a vaporcompression refrigeration cycle in instrumented automobile air conditioner bydesigning internal heat exchanger and installing it in the vapor compressionrefrigeration cycle. Two cases of vapor compression refrigeration cycle were takenin this paper: the first case is thatthe vapor compression refrigeration cycle without internal heat exchanger andin the second case the vapor compressionrefrigeration cycle with heat...
Performance analysis of adiabatic engine
Energy Technology Data Exchange (ETDEWEB)
Sudhakar, V.
1984-01-01
As the development of the adiabatic diesel engine continues with a goal of 65% reduction in net in-cylinder heat transfer over a cooled engine, several uncooled engines with intermediate levels of reduced heat transfer were studied. Some aspects and results of the adiabatic diesel engine cycle simulation are discussed. Performance test data and simulation results are compared for a conventionally cooled and uncooled Cummins NH-450 turbocompound engines. Exhaust emissions were also measured and compared.
Chen, Wei-Chun; Wang, Yih-Wen; Shu, Chi-Min
2016-06-01
Use of adiabatic calorimetry to characterise thermal runaway of Li-ion cells is a crucial technique in battery safety testing. Various states of charge (SoC) of Li-ion cells were investigated to ascertain their thermal runaway features using a Vent Sizing Package 2 (VSP2) adiabatic calorimeter. To evaluate the thermal runaway characteristics, the temperature-pressure-time trajectories of commercial cylindrical cells were tested, and it was found that cells at a SoC of greater than 50% were subject to thermal explosion at elevated temperatures. Calorimetry data from various 18650 Li-ion cells with different SoC were used to calculate the thermal explosion energies and chemical kinetics; furthermore, a novel self-heating model based on a pseudo-zero-order reaction that follows the Arrhenius equation was found to be applicable for studying the exothermic reaction of a charged cell.
Institute of Scientific and Technical Information of China (English)
Ke TANG; Juan YU; Tao JIN; Zhi-hua GAN
2013-01-01
Compression and expansion of a working gas due to the pressure oscillation of an oscillating flow can lead to a temperature variation of the working gas,which will affect the heat transfer in the oscillating flow.This study focuses on the impact of the compression-expansion effect,indicated by the pressure ratio,on the heat transfer in a finned heat exchanger under practical operating conditions of the ambient-temperature heat exchangers in Stirling-type pulse tube refrigerators.The experimental results summarized as the Nusselt number are presented for analysis.An increase in the pressure ratio can result in a marked rise in the Nussclt number,which indicates that the compression-expansion effect should be considered in characterizing the heat transfer of the oscillating flow,especially in the cases with a higher Valensi number and a lower maximum Reynolds number.
Institute of Scientific and Technical Information of China (English)
谭志诚; 张际标; 孟霜鹤; 李莉
1999-01-01
An automatic adiabatic calorimeter for measuring heat capacities in the temperature range 70—580 K, equipped with a small sample cell of 7.4 cm~3 in the internal volume has been developed. In order to obtain a good adiabatic condition of the calorimeter at high temperature, the calorimeter was surrounded in sequence by two adiabatic shields, three radiation shields and an auxiliary temperature-controlled sheath. The main body of the cell made of copper and the lid made of brass are silver-soldered and the cell is sealed with a copper screw cap. A sealing gasket made of Pb-Sn alloy is put between the cap and the lid to ensure a high vacuum sealing of the cell in the whole experimental temperature range. All the leads are insulated and fixed with W30-11 varnish, thus a good electric insulation is obtained at high temperature. All the experimental data, including those for energy and temperature are collected and processed automatically with a personal computer using a predetermined program. To verify the
DEFF Research Database (Denmark)
Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix;
2015-01-01
The ammonia-water hybrid absorption-compression heat pump (HACHP) has been proposed as a relevant technology for industrial heat supply, especially for high sink temperatures and high temperature glides in the sink and source. This is due to the reduced vapour pressure and the non-isothermal phase...... change of the zeotropic mixture, ammonia-water. To evaluate to which extent these advantages can be translated into feasible heat pump solutions, the working domain of the HACHP is investigated based on technical and economic constraints. The HACHP working domain is compared to that of the best available...... vapour compression heat pump with natural working fluids. This shows that the HACHP increases the temperature lifts and heat supply temperatures that are feasible to produce with a heat pump. The HACHP is shown to be capable of delivering heat supply temperatures as high as 150 °C and temperature lifts...
DEFF Research Database (Denmark)
Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars;
2015-01-01
Spray-drying facilities are among the most energy intensive industrial processes. Using a heat pump to recover waste heat and replace gas combustion has the potential to attain both economic and emissions savings. In the case examined a drying gas of ambient air is heated to 200 C yielding a heat...... load of 6.1 MW. The exhaust air from the drying process is 80 C. The implementation of anammonia–water hybrid absorption–compression heat pump to partly cover the heat load is investigated. A thermodynamic analysis is applied to determine optimal circulation ratios for a number of ammonia mass...
Hill, P R
1958-01-01
A method of calculating the temperature of thick walls has been developed in which the time series and the response to a unit triangle variation of surface temperature concepts are used, together with essentially standard formulas for transient temperature and heat flow into thick walls. The method can be used without knowledge of the mathematical tools of its development. The method is particularly suitable for determining the wall temperature in one-dimensional thermal problems in aeronautics where there is a continuous variation of the heat-transfer coefficient and adiabatic-wall temperature. The method also offers a convenient means for solving the inverse problem of determining the heat-flow history when temperature history is known.
Richards, Paul L.
2005-01-01
Mechanical heat switches are used in conjunction with sorption refrigerators, adiabatic demagnetization refrigerators and for other cryogenic tasks including the pre-cooling cryogenic systems. They use a mechanical actuator which closes Au plated Cu jaws on an Au plated Cu bar. The thermal conductance in the closed position is essentially independent of the area of the jaws and proportional to the force applied. It varies linearly with T. It is approximately 10mW/K for 200 N at 1.5K. In some applications, the heat switch can be driven from outside the cryostat by a rotating rod and a screw. Such heat switches are available commercially from several sources. In other applications, including systems for space, it is desirable to drive the switch using a cold linear motor, or solenoid. Superconducting windings are used at temperatures s 4.2K to minimize power dissipation, but are not appropriate for pre-cooling a system at higher temperatures. This project was intended to improve the design of solenoid activated mechanical heat switches and to provide such switches as required to support the development of Advanced Adiabatic Demagnetization Refrigerators for Continuous Cooling from 10 K to 50 mK at GSFC. By the time funding began in 5/1/01, the immediate need for mechanical heat switches at GSFC had subsided but, at the same time, the opportunity had arisen to improve the design of mechanical heat switching by incorporating a "latching solenoid". In this device, the solenoid current is required only for changing the state of the switch and not during the whole time that the switch is closed.
Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix; Reinholdt, L.; Elmegaard, Brian
2015-01-01
The ammonia-water hybrid absorption-compression heat pump (HACHP) has been proposed as a relevant technology for industrial heat supply, especially for high sink temperatures and high temperature glides in the sink and source. This is due to the reduced vapour pressure and the non-isothermal phase change of the zeotropic mixture, ammonia-water. To evaluate to which extent these advantages can be translated into feasible heat pump solutions, the working domain of the HACHP is investigated base...
EFFECTS OF COMPRESSED AIR FOAM APPLICATION ON HEAT
Directory of Open Access Journals (Sweden)
Adam THOMITZEK
2015-12-01
Full Text Available This article evaluates the knowledge obtained in firefighting tests using compressed air foam system (CAFS within a confined space. Six experiments were conducted for verification during the cooling of rooms and the self-extinguishing effect. The simulation was for a fully developed fire within a room. The fuel was chosen to simulate ordinary combustible materials utilized in residential areas. Mantel thermocouples were placed in the rooms to record the temperature changes. Compressed air foam was first applied with a standard fire hose nozzle to the ceiling and then to the epicenter of fire. Fire extinguishing was initiated after reaching the desired temperature in the room. The temperature for the start of fire extinguishing matched the third phase of development of a fire. Fire extinguishing was terminated after no obvious signs of fire were shown in epicenter of fire. The outputs of the experiments were evaluated on the basis of the amount of time passed for the temperature to drop below the suggested limit. Individual experiments were also conducted with various different admixing foaming agents over different locations. In the experiments, it has been verified that the application of compressed air foam has a positive effect on room cooling. Use of a compressed air foaming agent does not allow for the development of steam that can scald firefighters and reduce visibility. Furthermore, the extinguishing agent used is more efficient utilizing less water flow out of the fire area.
DEFF Research Database (Denmark)
Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars;
2015-01-01
The ammonia-water hybrid absorption-compression heat pump (HACHP) is a technology suitable for industrial scale heat pumps in the process industry. A helpful tool in the design of cost effective and low environmental impact energy conversion systems, such as the HACHP, is the application...
HEAT OF COMPRESSION AND OPPORTUNITY OF ITS USE FOR INCREASE OF EFFICIENCY OF AIR SEPARATION PLANTS
Лавренченко, Г. К.; Швец, С. Г.; Копытин, А. В.
2015-01-01
The analysis of possible directions useful utilization of heat of compression for production of the cold water in the heat-utilizing refrigerating machine and for organization heating vacuum regeneration of the adsorbent bloc of the desiccation and the purification of the air. Mark expediency of the application absorption lithium bromide refrigerating machines for organization preliminary cooling of the air in the air separation plant large productivity.
A blowup criterion for viscous, compressible, and heat-conductive magnetohydrodynamic flows
Du, Lili; Wang, Yongfu
2015-09-01
In this paper, we proved a blowup criterion for the two-dimensional (2D) viscous, compressible, and heat-conducting magnetohydrodynamic (MHD) flows for Cauchy problem, which depends only on the divergence of the velocity vector field, as well as for the case of bounded domain with Dirichlet boundary conditions. This result indicates that the nature of the blowup for compressible models of viscous media in 2D space is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model. More precisely, taking into account the magnetic effects and heat conductivity does not introduce any new features in the blowup mechanism of full MHD flows, especially, which is independent of the temperature and the magnetic field. The results also imply the global regularity of the strong solution to compressible MHD flows, provided that velocity divergence remains bounded.
Shell-structure effects on high-pressure Rankine-Hugoniot shock adiabats
Pain, J C
2007-01-01
Rankine-Hugoniot shock adiabats are calculated in the pressure range 1 Mbar-10 Gbar with two atomic-structure models: the atom in a spherical cell and the atom in a jellium of charges. These quantum self-consistent-field models include shell effects, which have a strong impact on pressure and shock velocity along the shock adiabat. Comparisons with experimental data are presented and quantum effects are interpreted in terms of electronic specific heat. A simple analytical estimate for the maximum compression is proposed, depending on initial density, atomic weight and atomic number.
Compression behavior of a ferritic-martensitic Cr-Mo steel
DEFF Research Database (Denmark)
Zhang, Zhenbo; Mishin, Oleg; Pantleon, Wolfgang
2012-01-01
The compression behavior of a ferritic-martensitic Cr-Mo steel is characterized for strain rates ranging from 10-4 s-1 to 10-1 s-1 and engineering strains up to 40%. Adiabatic heating causes a reduction in flow stress during continuous compression at a strain rate of 10-1 s-1. No reduction...
Jensen, Jonas Kjær; Reinholdt, Lars; Markussen, Wiebke Brix; Elmegaard, Brian
2014-01-01
The hybrid absorption/compression heat pump (HACHP) using ammonia-water as working fluid is a promising technology for development of a high temperature industrial heat pump. This is due to two properties inherent to the use of zeotropic mixtures: non-isothermal phase change and reduced vapour pressures. Using standard refrigeration components (28 bar) HACHP up to 100 °C are commercially available. Components developed for high pressure NH3 (52 bar) and transcritical CO2 (140 bar) increase th...
Waste Heat Approximation for Understanding Dynamic Compression in Nature and Experiments
Jeanloz, R.
2015-12-01
Energy dissipated during dynamic compression quantifies the residual heat left in a planet due to impact and accretion, as well as the deviation of a loading path from an ideal isentrope. Waste heat ignores the difference between the pressure-volume isentrope and Hugoniot in approximating the dissipated energy as the area between the Rayleigh line and Hugoniot (assumed given by a linear dependence of shock velocity on particle velocity). Strength and phase transformations are ignored: justifiably, when considering sufficiently high dynamic pressures and reversible transformations. Waste heat mis-estimates the dissipated energy by less than 10-20 percent for volume compressions under 30-60 percent. Specific waste heat (energy per mass) reaches 0.2-0.3 c02 at impact velocities 2-4 times the zero-pressure bulk sound velocity (c0), its maximum possible value being 0.5 c02. As larger impact velocities are implied for typical orbital velocities of Earth-like planets, and c02 ≈ 2-30 MJ/kg for rock, the specific waste heat due to accretion corresponds to temperature rises of about 3-15 x 103 K for rock: melting accompanies accretion even with only 20-30 percent waste heat retained. Impact sterilization is similarly quantified in terms of waste heat relative to the energy required to vaporize H2O (impact velocity of 7-8 km/s, or 4.5-5 c0, is sufficient). Waste heat also clarifies the relationship between shock, multi-shock and ramp loading experiments, as well as the effect of (static) pre-compression. Breaking a shock into 2 steps significantly reduces the dissipated energy, with minimum waste heat achieved for two equal volume compressions in succession. Breaking a shock into as few as 4 steps reduces the waste heat to within a few percent of zero, documenting how multi-shock loading approaches an isentrope. Pre-compression, being less dissipative than an initial shock to the same strain, further reduces waste heat. Multi-shock (i.e., high strain-rate) loading of pre-compressed
AN EXPERIMENTAL STUDY ON A VAPOR COMPRESSION REFRIGERATION CYCLE BY ADDING INTERNAL HEAT EXCHANGER
Directory of Open Access Journals (Sweden)
Muhammad Asmail Eleiwi
2013-05-01
Full Text Available Thispaper presents practical study to improve the indication COP of a vaporcompression refrigeration cycle in instrumented automobile air conditioner bydesigning internal heat exchanger and installing it in the vapor compressionrefrigeration cycle. Two cases of vapor compression refrigeration cycle were takenin this paper: the first case is thatthe vapor compression refrigeration cycle without internal heat exchanger andin the second case the vapor compressionrefrigeration cycle with heat exchanger ; in these two cases, the temperatureat each point of a vapor compressionrefrigeration cycle, the low and the high pressure ,the indoor temperature andthe outdoor temperature were measured at each time at compressor speed 1450 rpmand 2900 rpm for each blower speed 1, blower speed 2 and blower speed 3.Therefrigerant fluid was used in the vapor compression refrigeration cycle withoutIHE and with IHE is R134a..
In vitro burn model illustrating heat conduction patterns using compressed thermal papers.
Lee, Jun Yong; Jung, Sung-No; Kwon, Ho
2015-01-01
To date, heat conduction from heat sources to tissue has been estimated by complex mathematical modeling. In the present study, we developed an intuitive in vitro skin burn model that illustrates heat conduction patterns inside the skin. This was composed of tightly compressed thermal papers with compression frames. Heat flow through the model left a trace by changing the color of thermal papers. These were digitized and three-dimensionally reconstituted to reproduce the heat conduction patterns in the skin. For standardization, we validated K91HG-CE thermal paper using a printout test and bivariate correlation analysis. We measured the papers' physical properties and calculated the estimated depth of heat conduction using Fourier's equation. Through contact burns of 5, 10, 15, 20, and 30 seconds on porcine skin and our burn model using a heated brass comb, and comparing the burn wound and heat conduction trace, we validated our model. The heat conduction pattern correlation analysis (intraclass correlation coefficient: 0.846, p < 0.001) and the heat conduction depth correlation analysis (intraclass correlation coefficient: 0.93, p < 0.001) showed statistically significant high correlations between the porcine burn wound and our model. Our model showed good correlation with porcine skin burn injury and replicated its heat conduction patterns.
Institute of Scientific and Technical Information of China (English)
CHEN Jing-tao; DI You-ying; TAN Zhi-cheng; CHEN San-ping; GAO Sheng-li
2008-01-01
Low-temperature heat capacities of the solid compound Zn(C4H7O5)2(s) were measured in a temperature range from 78 to 374 K,with an automated adiabatic calorimeter.A solid-to-solid phase transition occurred in the temperature range of 295-322 K.The peak temperature,the enthalpy,and entropy of the phase transition were experimental values of the molar heat capacities in the temperature regions of 78-295 K and 322-374 K were fitted to two polynomial equations of heat capacities(Cp,m) with reduced temperatures(X) and [X=f(T)],with the help of the least squares method,respectively.The smoothed molar heat capacities and thermodynamic functions of the compound,relative to that of the standard reference temperature 293.15 K,were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K.In addition,the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.
Fractal Loop Heat Pipe Performance Comparisons of a Soda Lime Glass and Compressed Carbon Foam Wick
Myre, David; Silk, Eric A.
2014-01-01
This study compares heat flux performance of a Loop Heat Pipe (LHP) wick structure fabricated from compressed carbon foam with that of a wick structure fabricated from sintered soda lime glass. Each wick was used in an LHP containing a fractal based evaporator. The Fractal Loop Heat Pipe (FLHP) was designed and manufactured by Mikros Manufacturing Inc. The compressed carbon foam wick structure was manufactured by ERG Aerospace Inc., and machined to specifications comparable to that of the initial soda lime glass wick structure. Machining of the compressed foam as well as performance testing was conducted at the United States Naval Academy. Performance testing with the sintered soda lime glass wick structures was conducted at NASA Goddard Space Flight Center. Heat input for both wick structures was supplied via cartridge heaters mounted in a copper block. The copper heater block was placed in contact with the FLHP evaporator which had a circular cross-sectional area of 0.88 cm(sup 2). Twice distilled, deionized water was used as the working fluid in both sets of experiments. Thermal performance data was obtained for three different Condenser/Subcooler temperatures under degassed conditions. Both wicks demonstrated comparable heat flux performance with a maximum of 75 W/cm observed for the soda lime glass wick and 70 W /cm(sup 2) for the compressed carbon foam wick.
Influence of exercise training with thigh compression on heat-loss responses.
Amano, T; Inoue, Y; Koga, S; Nishiyasu, T; Kondo, N
2015-06-01
We investigated the effect of thigh compression, which accelerates activation of central command and muscle metabo- and mechanoreceptors, on the adaptation of sweating and cutaneous vascular responses during exercise heat acclimation. Nine non-heat-acclimated male subjects were acclimated to heat (32 °C and 50% RH) while cycling [50% of maximum oxygen uptake ( V ˙ O 2 m a x )] 60 min/day for 7 days (control group). The experimental group (n = 9) conducted the same training while the proximal thighs were compressed by a cuff at 60 mmHg. V ˙ O 2 m a x , acetylcholine-induced forearm sweating rate (iontophoresis), and mean sweating and cutaneous vascular responses on the forehead, chest, and forearm (SRmean and CVCmean ) during passive heating were evaluated before and after training. Training significantly increased V ˙ O 2 m a x while did not affect acetylcholine-induced sweating rates in either group. Training significantly decreased Tb thresholds for SRmean and CVCmean during passive heating without the alternations of sensitivities in both groups. Although SRmean during passive heating at a given ΔTb was not improved in either group, CVCmean was significantly (P training only in experimental group. Our results indicate that thigh cuff compression during exercise heat acclimation does not influence adaptation of the sweating response but attenuate cutaneous vasodilation.
DEVELOPMENT OF COLD CLIMATE HEAT PUMP USING TWO-STAGE COMPRESSION
Energy Technology Data Exchange (ETDEWEB)
Shen, Bo [ORNL; Rice, C Keith [ORNL; Abdelaziz, Omar [ORNL; Shrestha, Som S [ORNL
2015-01-01
This paper uses a well-regarded, hardware based heat pump system model to investigate a two-stage economizing cycle for cold climate heat pump applications. The two-stage compression cycle has two variable-speed compressors. The high stage compressor was modelled using a compressor map, and the low stage compressor was experimentally studied using calorimeter testing. A single-stage heat pump system was modelled as the baseline. The system performance predictions are compared between the two-stage and single-stage systems. Special considerations for designing a cold climate heat pump are addressed at both the system and component levels.
Changes of Chemical Composition and Crystalline of Compressed Chinese Fir Wood in Heating Fixation
Institute of Scientific and Technical Information of China (English)
Tang Xiaoshu; Zhao Guangjie; Nakao Tetsuya
2004-01-01
The changes in relative crystalline, chemical composition and internal structure of compressed Chinese fir wood after different heating fixations were found strictly related to fixation conditions. The compressed wood powders were fixed either by heating at different temperatures all resulting in a 10% recovery, or by incubating at 180 °C for different periods with subsequent recovery levels. Both X-ray diffraction and infrared absorption of those samples have been measured. Relative crystalline increases at early stage of heating fixation, and then decreased gradually. Hemicellulose and lignin decomposition were induced by the fixation process, especially at 180 °C, and lignin was degraded actively. Furthermore, absorbed water was lost after heating, but cellulose did not change markedly. Although different fixation pathways can result in the same recovery level, the major chemical reactions underlying them vary, which is consistent with the difference of fixation mechanisms.
Wall-Laws for High Speed Flows over Adiabatic and Isothermal Walls
Mohammadi, Bijan; Puigt, Guillaume
2000-01-01
We present the extension of our wall-laws developed for low-speed flows to super and hypersonic configurations. In particular, we are interested in flows over isothermal walls and account for heat transfer. We recall the main steps of the development: - Obtention of generalized wall functions for low-speed fluids, valid for all $y^+$, - Taking into account transversal effects. - Accounting for the compressible feature of the flow on adiabatic walls without using informations on the local boun...
Compressed air energy storage with waste heat export: An Alberta case study
International Nuclear Information System (INIS)
Highlights: • Export of compression waste heat from CAES facilities for municipal heating can be profitable. • D-CAES concept has a negative abatement cost of −$40/tCO2e under the studied circumstances. • Economic viability of D-CAES highly depends on distance between air storage site and heat load. - Abstract: Interest in compressed air energy storage (CAES) technology has been renewed driven by the need to manage variability form rapidly growing wind and solar capacity. Distributed CAES (D-CAES) design aims to improve the efficiency of conventional CAES through locating the compressor near concentrated heating loads so capturing additional revenue through sales of compression waste heat. A pipeline transports compressed air to the storage facility and expander, co-located at some distance from the compressor. The economics of CAES are strongly dependant on electricity and gas markets in which they are embedded. As a case study, we evaluated the economics of two hypothetical merchant CAES and D-CAES facilities performing energy arbitrage in Alberta, Canada using market data from 2002 to 2011. The annual profit of the D-CAES plant was $1.3 million more on average at a distance of 50 km between the heat load and air storage sites. Superior economic and environmental performance of D-CAES led to a negative abatement cost of −$40/tCO2e. We performed a suite of sensitivity analyses to evaluate the impact of size of heat load, size of air storage, ratio of expander to compressor size, and length of pipeline on the economic feasibility of D-CAES
Heat transfer analysis of liquid piston compressor for hydrogen applications
DEFF Research Database (Denmark)
Kermani, Nasrin Arjomand; Rokni, Masoud
2015-01-01
A hydrogen compression technology using liquid as the compression piston is investigated from heat transfer point of view. A thermodynamic model, simulating a single compression stroke, is developed to investigate the heat transfer phenomena inside the compression chamber. The model is developed...... and through the walls, is investigated and compared with the adiabatic case. The results show that depending on heat transfer correlation, the hydrogen temperature reduces slightly between 0.2% and 0.4% compared to the adiabatic case, at 500bar, due to the large wall resistance and small contact area...... at the interface. Moreover, the results of the sensitivity analysis illustrates that increasing the total heat transfer coefficients at the interface and the wall, together with compression time, play key roles in reducing the hydrogen temperature. Increasing the total heat transfer coefficient at the interface...
International Nuclear Information System (INIS)
Highlights: • Optimal compression ratio of CASAHP is obtained for the maximum energy saving rate. • Annual performance is improved by 10–20% compared to ASAHP without compression. • Energy saving rate is 17.7–29.2% and investment is reduced to 30–60% for CASAHP. • Both compression and partial-design enhance the economy with given energy saving. • Payback time is reduced from 12–32 to 3–6 years by compression and partial-design. - Abstract: The compression-assisted air source absorption heat pump (CASAHP) is a promising alternative heating system in severe operating conditions. In this research, parameter studies on the annual performance under various compression ratios (CRs) and source temperatures are performed to achieve the maximum energy saving rates (ESRs). Economic analyses of the CASAHP under different CRs and partial-design ratios are conducted to obtain an optimal design that considers both energy savings and economy improvements. The results show that the optimal CR becomes higher in colder regions and with lower heat source temperatures. For a source temperature of 130 °C, the optimal CR values in all of the cities are within 2.0. For source temperatures from 100 to 130 °C, the maximum ESR is in the range of 17.7–29.2% in the studied cities. The efficiency improvement rate (EIR) caused by compression in a severe source condition can reach 10.0–20.0%. From the viewpoint of economy, the relative investment of CASAHP is reduced to 30–60% with a CR of 2.0–3.0. With a 2–6% sacrifice in ESR, the payback period can be reduced from 12–32 to 5–9 years using compression. Partial-design of the CASAHP can further reduce the payback period to 3–6 years with a partial-design ratio of 50% and a CR of 2.8. Additionally, CRs and partial-design ratios are designed comprehensively by seeking the maximum ESR for a given acceptable payback period
Ivanov, V. A.
2010-12-01
The possibility of ensuring equivalence in operation and efficiency of real cycles with intermediate cooling (heating) and isothermal-adiabatic compressions (expansion) in ideal simple cycles formed on the T- S diagrams in the second stage of real cycles. The possibility of using the equivalence of cycles for determining the maximum efficiency of operation of real cycles is demonstrated.
Fast electron heating of shock compressed solids at high intensities relevant to fast ignition
International Nuclear Information System (INIS)
This report describes the experiment entitled 'Fast electron heating of shock compressed solids at high intensities relevant to fast ignition'; carried out at the Central Laser Facility (CLF) from the 5th January to the 15th February 1997. The experiment, funded by the Framework IV Large-Scale Facilities Access Scheme, was proposed by Dr. D. Batani, University of Milan, Italy and carried out by visiting researchers from the University and Ecole Polytechnique, Palaiseau, France. They were supported by UK researchers from the University of Essex, the University of Bristol and the Central Laser Facility, Rutherford Appleton Laboratory. Experimental results: (i) The experiment demonstrated the first results for fast electron deposition in compressed matter. The irradiances used in these experiments are lower than would be used in the fast ignitor scheme but the significance of the results is, nevertheless very relevant to this scheme. (ii) It is shown that in the experiments presented here that ionised, compressed plastic is less effective at stopping the fast electrons than uncompressed, unionised plastic. The stopping power of the compressed material is reduced by a factor of two (in areal density units) over the uncompressed materials. (iii) These experiments are the first measurements of electron stopping power in compressed plasmas but further experiments with more highly compressed plasmas are necessary before the results may be safely extrapolated to fast ignitor conditions. (author)
Shornikov, A; Wolf, A
2014-01-01
We present design and commissioning results of a forced flow cooling system utilizing neon at 30 K. The cryogen is pumped through the system by a room-temperature compression stage. To decouple the cold zone from the compression stage a recuperating counterflow tube-in-tube heat exchanger is used. Commissioning demonstrated successful condensation of neon and transfer of up to 30 W cooling power to the load at 30 K using only 30 g of the cryogen circulating in the system at pressures below 170 kPa.
Erickson, Lisa R.; Ungar, Eugene K.
2012-01-01
Humans on a spacecraft require significant amounts of water for drinking, food, hydration, and hygiene. Maximizing the reuse of wastewater while minimizing the use of consumables is critical for long duration space exploration. One of the more promising consumable-free methods of reclaiming wastewater is the distillation/condensation process used in the Cascade Distillation Subsystem (CDS). The CDS heats wastewater to the point of vaporization then condenses and cools the resulting water vapor. The CDS wastewater flow requires heating for evaporation and the product water flow requires cooling for condensation. Performing the heating and cooling processes separately would require two separate units, each of which would demand large amounts of electrical power. Mass, volume, and power efficiencies can be obtained by heating the wastewater and cooling the condensate in a single heat pump unit. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the CDS system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump analysis and performance tests are provided. The mass, volume, and power requirement for each heat pump option is compared and the advantages and disadvantages of each system are listed.
Directory of Open Access Journals (Sweden)
Bing Hu
2015-05-01
Full Text Available To develop the organic Rankine-vapor compression ice maker driven by food industry exhaust gases and engine cooling water, an organic Rankine-vapor compression cycle system was employed for ice making and a thermodynamic model was developed and the effects of working fluid types, hot water temperature and condensation temperature on the system performance were analyzed and the ice making capacity from unit mass hot water and unit power waste heat were evaluated. The calculated results show that the working fluid type and the temperatures of heat source and condensation have important effects on the system performance. The system can achieve optimal performance when use R245fa as power and refrigeration medium. The ice quantity generated from per ton hot water is 86.42 kg and the ice-making rate for per kW waste heat is 2.27 kg/h, when the temperatures of hot water and condensation are respectively 100 and 40°C. A conclusion can be draw by the calculation and analysis that using organic Rankine-vapor compression system for ice making from food industry waste heat is feasible.
Bandyopadhyay, Alak; Majumdar, Alok
2007-01-01
The present paper describes the verification and validation of a quasi one-dimensional pressure based finite volume algorithm, implemented in Generalized Fluid System Simulation Program (GFSSP), for predicting compressible flow with friction, heat transfer and area change. The numerical predictions were compared with two classical solutions of compressible flow, i.e. Fanno and Rayleigh flow. Fanno flow provides an analytical solution of compressible flow in a long slender pipe where incoming subsonic flow can be choked due to friction. On the other hand, Raleigh flow provides analytical solution of frictionless compressible flow with heat transfer where incoming subsonic flow can be choked at the outlet boundary with heat addition to the control volume. Nonuniform grid distribution improves the accuracy of numerical prediction. A benchmark numerical solution of compressible flow in a converging-diverging nozzle with friction and heat transfer has been developed to verify GFSSP's numerical predictions. The numerical predictions compare favorably in all cases.
Cummins/Tacom advanced adiabatic engine
Energy Technology Data Exchange (ETDEWEB)
Kamo, R.; Bryzik, W.
1984-01-01
Cummins Engine Company, Inc. and the U.S. Army have been jointly developing an adiabatic turbocompound engine during the last nine years. Although progress in the early years was slow, recent developments in the field of advanced ceramics have made it possible to make steady progress. It is now possible to reconsider the temperature limitation imposed on current heat engines and its subsequent influence on higher engine efficiency when using an exhaust energy utilization system. This paper presents an adiabatic turbocompound diesel engine concept in which high-performance ceramics are used in its design. The adiabatic turbocompound engine will enable higher operating temperatures, reduced heat loss, and higher exhaust energy recovery, resulting in higher thermal engine efficiency. This paper indicates that the careful selection of ceramics in engine design is essential. Adiabatic engine materials requirements are defined and the possible ceramic materials which will satisfy these requirements are identified. Examples in design considerations of engine components are illustrated. In addition to these important points, the use of ceramic coatings in the design of engine components. The first generation adiabatic engine with ceramic coatings is described. The advanced adiabatic engine with minimum friction features utilizaing ceramics is also presented. The advanced ceramic turbocharger turbine rotor as well as the oilless ceramic bearing design is described. Finally, the current status of the advanced adiabatic engine program culminating in the AA750 V-8 adiabatic engine is presented.
Tilt stability and compression heating studies of field-reversed configurations
International Nuclear Information System (INIS)
The first observations of internal tilt instabilities in field-reversed configurations (FRCs) are reported. Detailed comparisons with theory establish that data from an array of external magnetic probes are signatures of these destructive plasma instabilities. This work reconciles theory and experiments and suggests that grossly stable FRCs are restricted to very kinetic and elongated plasmas. Self-consistent three-dimensional numerical simulations demonstrate tilt stabilization by the addition of a beam ion component. High-power compression heating experiments with stable equilibrium FRCs are also reported. Plasmas formed in a tapered theta-pinch coil have been translated along a guide magnetic field into a new single-turn compression coil where the external field is increased up to 7 times the initial value in 55 μs. Substantial heating is observed accompanied by a decrease in confinement time. 17 refs
Nattaporn Chaiyat; Tanongkiat Kiatsiriroat
2014-01-01
In this study, simulation and experiment studies of a 10 kW solar H2O–LiBr absorption heat transformer (AHT) integrating with a two-stage vapor compression heat pump (VCHP) were carried out. The whole system was named as compression/absorption heat transformer (CAHT). The VCHP was used to recover rejected heat at the AHT condenser which was transferred back to the AHT evaporator at a higher temperature. The AHT unit took solar heat from a set of flat-plate solar collectors in parallel connect...
Saclay Reactor: acquired knowledge by two years experience in heat transfer using compressed gas
International Nuclear Information System (INIS)
Describes the conception and functioning of a new reactor (EL-2) using compressed gas as primary coolant. The aim of the use of compressed gas as primary coolant is to reduce the quantity of heavy water used in the functioning of the reactor. Description of the reactor vessel (dimensions, materials, reflector and protection). Description of the cells and the circulation of the gas within the cells. A complete explanation of the control and regulating of the reaction by the ionization chamber is given. Heavy water is used as modulator: it describes the heavy water system and its recombination system. The fuel slugs are cooled by compressed gas: its system is described as well as the blower and the heat exchanger system. Water is supplied by a cooling tower which means the reactor power is dependant of the atmospheric conditions. Particular attention has been given to the tightness of the different systems used. The relation between neutron flow and the thermal output is discussed: the thermal output can be calculated by measuring the gas flow and its heating or by measuring the neutron flow within the reactor, both methods gives closed results. Reactivity study: determination of the different factors which induce a variation of reactivity. Heat transfer: discussion on the use of different heat transfer systems, determination of the required chemical and physical properties of the primary coolant as well as the discussion of the nuclear and thermal requirements for the choice of it. A comparison between the use of nitrogen and carbon dioxide gas shows an advantage in using nitrogen with the existing knowledge. Reflexion on the relevance of this work and the future perspectives of the use of compressed gas as primary coolant. (M.P.)
Time decay rates for the equations of the compressible heat-conductive flow through porous media
Chen, Qing; Tan, Zhong; Wu, Guochun
2015-11-01
We consider the time decay rates of smooth solutions to the Cauchy problem for the equations of the compressible heat-conductive flow through porous media. We prove the global existence and uniqueness of the solutions by the standard energy method. Moreover, we establish the optimal decay rates of the solution as well as its higher-order spatial derivatives. And the damping effect on the time decay rates of the solution is studied in detail.
Modeling Granular Materials as Compressible Non-Linear Fluids: Heat Transfer Boundary Value Problems
Energy Technology Data Exchange (ETDEWEB)
Massoudi, M.C.; Tran, P.X.
2006-01-01
We discuss three boundary value problems in the flow and heat transfer analysis in flowing granular materials: (i) the flow down an inclined plane with radiation effects at the free surface; (ii) the natural convection flow between two heated vertical walls; (iii) the shearing motion between two horizontal flat plates with heat conduction. It is assumed that the material behaves like a continuum, similar to a compressible nonlinear fluid where the effects of density gradients are incorporated in the stress tensor. For a fully developed flow the equations are simplified to a system of three nonlinear ordinary differential equations. The equations are made dimensionless and a parametric study is performed where the effects of various dimensionless numbers representing the effects of heat conduction, viscous dissipation, radiation, and so forth are presented.
On the development of high temperature ammonia-water hybrid absorption-compression heat pumps
DEFF Research Database (Denmark)
Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars;
2015-01-01
Ammonia-water hybrid absorption-compression heat pumps (HACHP) are a promising technology for development of ecient high temperature industrial heat pumps. Using 28 bar components HACHPs up to 100 °C are commercially available. Components developed for 50 bar and 140 bar show that these pressure...... limits may be possible to exceed if needed for actual applications. Feasible heat supply temperatures using these component limits are investigated. A feasible solution is defined as one that satisfies constraints on the COP, low and high pressure, compressor discharge temperature, vapour water content...... and volumetric heat capacity. The ammonia mass fraction and the liquid circulation ratio both influence these constraining parameters. The paper investigates feasible combinations of these parameters through the use of a numerical model. 28 bar components allow temperatures up to 111 °C, 50 bar up to 129°C...
Energy Technology Data Exchange (ETDEWEB)
Babakhani, D. [Department of Chemical Engineering, Faculty of Engineering, University of Isfahan (Iran, Islamic Republic of)
2009-12-15
An analytical solution of simultaneous heat and mass transfer processes in a packed bed liquid desiccant dehumidifier/regenerator is developed. Various dimensionless parameters and reliable assumptions are used in order to develop this solution. The outlet parameters predicted with the analytical solution show very good agreement with the experimental data available in the literature. The results show that using a Lewis number value of Le=1.1 instead of Le=1 gives a better prediction of the performance of the dehumidifier. In addition, the use of Le=0.9 instead of Le=1 can give a better prediction of the outlet parameters of the regenerator. The benefits of the present solution are its simplicity and easy application for the simulation of air dehumidification and liquid desiccant regeneration processes. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
DEFF Research Database (Denmark)
Ommen, Torben Schmidt; Jensen, Jonas Kjær; Markussen, Wiebke Brix;
2014-01-01
A large amount of operational and economic constraints limit the applicability of heat pumps operated with natural working fluids. The limitations are highly dependent on the integration of heat source and sink streams. An evaluation of feasible operating conditions is carried out considering the...
Institute of Scientific and Technical Information of China (English)
Xu Xinying
2012-01-01
In this paper; we prove a blow-up criterion of strong solutions to the 3-D viscous and non-resistive magnetohydrodynamic equations for compressible heat-conducting flows with initial vacuum.This blow-up criterion depends only on the gradient of velocity and the temperature,which is similar to the one for compressible Navier-Stokes equations.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The effects of heat treatment on the dynamic compressive properties and energy absorption characteristics of open cell aluminum alloy foams (Al-Mg-Si alloy foam and Al-Cu-Mg alloy foam) produced by infiltrating process were studied. Two kinds of heat treatment were exploited: age-hardening and solution heat treating plus age-hardening (T6). The split Hopkinson pressure bar (SHPB)was used for high strain rate compression test. The results show that both age-hardened and T6-strengthened foams exhibit improved compression strength and shortened plateau region compared with tnat of foams in as-fabricated state under high strain rate compression,and the energy absorption capacity is also influenced significantly by heat treatment. It is worthy to note that omitting the solution treating can also improve the strength and energy absorbed much.
DEFF Research Database (Denmark)
Jensen, Jonas Kjær; Reinholdt, Lars; Markussen, Wiebke Brix;
2014-01-01
and the liquid circulation ratio both influence these constraints. The paper investigates feasible combinations of these parameters. A numerical HACHP model is developed in Engineering Equation Solver (EES). The constrained parameters are evaluated for a range of combinations for systems with supply temperatures......The hybrid absorption/compression heat pump (HACHP) using ammonia-water as working fluid is a promising technology for development of a high temperature industrial heat pump. This is due to two properties inherent to the use of zeotropic mixtures: non-isothermal phase change and reduced vapour...... pressures. Using standard refrigeration components (28 bar) HACHP up to 100 °C are commercially available. Components developed for high pressure NH3 (52 bar) and transcritical CO2 (140 bar) increase the limiting allowable pressures. It is therefore relevant to evaluate the feasible supply temperatures...
Determination of the Specific Heat Ratio of a Gas in a Plastic Syringe
Chamberlain, Jeff
2010-01-01
The rapid compression or expansion of a gas in a plastic syringe is a poor approximation of an adiabatic process. Heat exchange with the walls of the syringe brings the gas to equilibrium in an amount of time that is not significantly greater than the length of the compression or expansion itself. Despite this limitation, it is still possible to…
DEFF Research Database (Denmark)
Østergaard, Poul Alberg
2013-01-01
-temperature geothermal resources. The analyses have also demonstrated that the municipality will still rely heavily on surrounding areas for electric load balancing assistance. With a departure in a previously elaborated 100% renewable energy scenario, this article investigates how absorption heat pumps (AHP...
Assessment of total efficiency in adiabatic engines
Mitianiec, W.
2016-09-01
The paper presents influence of ceramic coating in all surfaces of the combustion chamber of SI four-stroke engine on working parameters mainly on heat balance and total efficiency. Three cases of engine were considered: standard without ceramic coating, fully adiabatic combustion chamber and engine with different thickness of ceramic coating. Consideration of adiabatic or semi-adiabatic engine was connected with mathematical modelling of heat transfer from the cylinder gas to the cooling medium. This model takes into account changeable convection coefficient based on the experimental formulas of Woschni, heat conductivity of multi-layer walls and also small effect of radiation in SI engines. The simulation model was elaborated with full heat transfer to the cooling medium and unsteady gas flow in the engine intake and exhaust systems. The computer program taking into account 0D model of engine processes in the cylinder and 1D model of gas flow was elaborated for determination of many basic engine thermodynamic parameters for Suzuki DR-Z400S 400 cc SI engine. The paper presents calculation results of influence of the ceramic coating thickness on indicated pressure, specific fuel consumption, cooling and exhaust heat losses. Next it were presented comparisons of effective power, heat losses in the cooling and exhaust systems, total efficiency in function of engine rotational speed and also comparison of temperature inside the cylinder for standard, semi-adiabatic and full adiabatic engine. On the basis of the achieved results it was found higher total efficiency of adiabatic engines at 2500 rpm from 27% for standard engine to 37% for full adiabatic engine.
Adiabatic Flame Temperature for Combustion of Methane
Directory of Open Access Journals (Sweden)
Rebeca Pupo
2011-01-01
Full Text Available This project calculated the adiabatic flame temperature of a combustion reaction of pure methane and oxygen, assuming that all of the heat liberated by the combustion reaction goes into heating the resulting mixture. Mole fractions of methane to oxygen were computed from 0.05 to 0.95, in increments of 0.05, and then an integral was computed was computed with respect to temperature using the moles of product produced or leftover moles of reactants from the starting mole fraction times the specific heat of each respective gas. The highest adiabatic flame temperature evaluated, occurred at a mole fraction of 0.35.
A study on dynamic characteristics of tuff with the triaxial compression tests on heating
International Nuclear Information System (INIS)
To discuss mechanics and hydrological characteristics in rock at a long period, we need to refer to the change of discontinuous surface and construction with the thermal and the chemical changes. In this study, the consolidated-drained triaxial compression tests with comparatively soft tuff were conducted, and the slide-hold-slide process in a residual state was applied. These conditions of the effective confining stress and temperature, the degree of the healing at the shear band, occurring of the shear process was confirmed. As a result, we confirmed the healing, moreover, the proportion of the healing to the holding time. However, in heating, the degree of the healing became decreased. (author)
Study on Operating Performance of Stirling Engine-Driven Vapor Compression Heat Pump System
Kagawa, Noboru
Stirling engines have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration. On the other hand, heat pump systems are very attractive for space heating and cooling, and industrial usage. There are several environmental merits of Stirling driven vapor compression (SDVC) systems. A design method for the SDVC, which is based on mathematical methods for Stirling and Ranking cycles, has been developed. The attractive SDVC performance using conventional and alternative refrigerants was shown. From the calculated Total Equivalent Warming Impact (TEWI) and operating costs, it became clear that the SDVC system with the alternative refrigerant has a higher potential as the future air-conditioning system.
He, Jiansen; Marsch, Eckart; Chen, Christopher H K; Wang, Linghua; Pei, Zhongtian; Zhang, Lei; Salem, Chadi S; Bale, Stuart D
2015-01-01
Magnetohydronamic turbulence is believed to play a crucial role in heating the laboratorial, space, and astrophysical plasmas. However, the precise connection between the turbulent fluctuations and the particle kinetics has not yet been established. Here we present clear evidence of plasma turbulence heating based on diagnosed wave features and proton velocity distributions from solar wind measurements by the Wind spacecraft. For the first time, we can report the simultaneous observation of counter-propagating magnetohydrodynamic waves in the solar wind turbulence. Different from the traditional paradigm with counter-propagating Alfv\\'en waves, anti-sunward Alfv\\'en waves (AWs) are encountered by sunward slow magnetosonic waves (SMWs) in this new type of solar wind compressible turbulence. The counter-propagating AWs and SWs correspond respectively to the dominant and sub-dominant populations of the imbalanced Els\\"asser variables. Nonlinear interactions between the AWs and SMWs are inferred from the non-orth...
Isobaric heat capacity, isothermal compressibility and fluctuational properties of 1-bromoalkanes
Korotkovskii, V I; Neruchev, Yu A; Goncharov, A L; Postnikov, E B
2016-01-01
We present results of the experimental measurements of the isobaric heat capacity for 1-bromohexane, 1-bromoheptane, 1-bromooctane, 1-bromononane, 1-bromodecane, 1-bromoundecane, 1-bromododecane and 1-bromo-tetradecane at normal pressure and the speed of sound and the density for 1-bromotetradecane within the temperature range 298.15--423.15~K. These data on the isobaric heat capacity and the literature-based reference data for the density and the speed of sound were used to calculate the isothermal compressibility and the inverse reduced fluctuations. Based on the comparison of the results for pure n-alkanes and $\\alpha,\\omega$-dibromoalkanes, we discuss the influence of bromine atom on the volume fluctuations.
Isobaric Heat Capacity, Isothermal Compressibility and Fluctuational Properties of 1-Bromoalkanes
Korotkovskii, V. I.; Ryshkova, O. S.; Neruchev, Yu. A.; Goncharov, A. L.; Postnikov, E. B.
2016-06-01
We present results of the experimental measurements of the isobaric heat capacity for 1-bromohexane, 1-bromoheptane, 1-bromooctane, 1-bromononane, 1-bromodecane, 1-bromoundecane, 1-bromododecane and 1-bromotetradecane at normal pressure and the speed of sound and the density for 1-bromotetradecane within the temperature range 298.15-423.15 K. These data on the isobaric heat capacity and the literature-based reference data for the density and the speed of sound were used to calculate the isothermal compressibility and the inverse reduced fluctuations. Based on the comparison of the results for pure n-alkanes and α ,ω -dibromoalkanes, we discuss the influence of bromine atom on the volume fluctuations.
Plasma heat pump and heat engine
International Nuclear Information System (INIS)
A model system where cold charged particles are locally confined in a volume VP within a warm plasma of volume V (VPE. The law of thermodynamics involving PE and an equation of state for PE are obtained. It is shown that the expansion/compression of electrostatic fields associated with charged particles is a new mechanism that converts mechanical work into plasma heat and vice versa. Two applications of this theory are, first we propose a pumping device which heats plasmas by an adiabatic/isothermal compression of fields. Heating power ranging from a few hundred watts to a few kilowatts is possible with the present day technology. Second, we discuss the feasibility of constructing an electrostatic heat engine which converts plasma heat into mechanical work via plasma electric fields. Effects of PE are shown to be observable in colloidal solutions.
A theoretical and experimental study of high-temperature compressive gas heating
Blekhman, David Iosifovich
The temperature rise due to compression, although considered as undesirable in most pumping applications, can be utilized to produce an uncontaminated, high-temperature (>1500K), uniformly heated stream of gas. Based on the Roots principle, Multi-Recompression Heater (MRH) is being designed to provide such capabilities. The potential applications include pyrolitic synthesis of chemical compounds, waste and chemical munitions decomposition, optical fiber production and high temperature experimental studies. Future heater design strategies are dependent on thorough understanding of the physical mechanisms and improved modeling capabilities of the compression processes in Roots compressors. In this study, a multi-control volume model is presented. Three control volumes are employed. The well-filling process is modeled via expansion of the compressed gas from the high-pressure reservoir into the well through a "nozzle" formed by the rotor tip and the blower casing. The nozzle has a time-varying geometry and is modeled to allow transition from choked to non-choked flow. When the pressures equalize, the gas in the well is assumed to be fully-mixed and the two control volumes are subsequently considered as one. Numerical computations of the time required for the expansion-mixing process, and the time histories of the pressures and temperatures in the control volumes are performed. Two series of experiments are conducted using a Dresser-Roots Whispair RAM 404 blower at speeds of 2280 and 3430 rpm. The data is collected via ten channels: four for pressure and six for temperature measurements. The experiment control and data recording are made with LabView. The maximum temperature allowed by the unmodified compressor before it would seize up was about 700K. Measured heat transfer and leakage rates are used in calculations. Their representation may be improved by introducing more detailed models. The model presented contains dimensionless compression and thermal transport
Dark Energy and Dark Matter from an additional adiabatic fluid
Dunsby, Peter K. S.; Luongo, Orlando; Reverberi, Lorenzo
2016-01-01
The Dark Sector is described by an additional barotropic fluid which evolves adiabatically during the universe's history and whose adiabatic exponent $\\gamma$ is derived from the standard definitions of specific heats. Although in general $\\gamma$ is a function of the redshift, the Hubble parameter and its derivatives, we find that our assumptions lead necessarily to solutions with $\\gamma = $ constant in a FLRW universe. The adiabatic fluid acts effectively as the sum of two distinct compone...
Adiabatic turbocompound diesel engine
Energy Technology Data Exchange (ETDEWEB)
Kamo, R.; Bryzik, W.
1984-02-01
The research and development of an adiabatic turbocompound engine have shown that the concept is feasible. The ability to meet the performance and sociability goals of the future power plants has been demonstrated. Low brake specific fuel consumption, low smoke and particulates, better NO /SUB x/ -BSFC trade-off, excellent multifuel capability, white smoke suppression, and potentially lower maintenance and greater reliability and durability are some of the attributes. The absence of the water cooling system adds to its attractiveness because of lower installed weight, cost, and reduction in parasitic losses. The operating environment of an adiabatic engine is shown as the basis for analysis and designing of adiabatic components. The types of material which can satisfy the needs of an adiabatic engine are presented. These materials include high temperature metals, high performance ceramics, and glass ceramics. The use of a turbocompound system to utilize the increased exhaust energy of an adiabatic engine is covered. A minimum fuel consumption of 0.285 lb/bhp-hr was achieved at 200 psi BMEP. Although the technical feasibility and viability of an adiabatic engine was demonstrated, the adiabatic diesel engine has problems which must be solved before it becomes a commercially viable product. These problem areas where more work is required are discussed.
Experimental study on the adiabatic shear bands
International Nuclear Information System (INIS)
Four martensitic steels (Z50CDV5 steel, 28CND8 steel, 35NCDV16 steel and 4340 steel) with different hardness between 190 and 600 Hsub(B) (Brinell hardness), have been studied by means of dynamic compressive tests on split Hopkinson pressure bar. Microscopic observations show that the fracture are associated to the development of adiabatic shear bands (except 4340 steel with 190 Hsub(B) hardness). By means of tests for which the deformation is stopped at predetermined levels, the measurement of shear and hardness inside the band and the matrix indicates the chronology of this phenomenon: first the localization of shear, followed by the formation of adiabatic shear band and ultimatly crack initiation and propagation. These results correlated with few simulations by finite elements have permitted to suggest two mecanisms of deformation leading to the formation of adiabatic shear bands in this specific test
International Nuclear Information System (INIS)
Highlights: • Thermodynamic analysis of a solar driven power plant running on the Braysson cycle. • Isothermal compression is implemented by the use of multistage intercooled compression stages. • The plant’s thermal efficiency is investigated and compared against other cycles. - Abstract: The present study develops the thermodynamic analysis for the cycle of a solar-driven, Braysson cycle based plant in the ideal limit and in the presence of process irreversibilities. The plant cycle differs from the conventional idealized Braysson cycle in that the implementation of the final isothermal compression process is substituted by a multistep intercooled compression. The cycle’s efficiency is analytically formulated after taking into account several loss (irreversibility) sources such as the non-isentropic behavior of the main compressor, the power turbine and the intercooled compressor stages as well as the actual heat transferred through countercurrent heat exchangers. All pressure losses associated with heat exchangers are related to the actual heat transfer load within each exchanger. The analysis develops a parametric evaluation for the effectiveness of the main cycle free variables on the thermal efficiency of the cycle. Such free variables include the working fluid maximum temperature, the compressor pressure ratio and the operating temperature limits of the intercooled compression stages, in addition to the polytropic coefficients of the compressor and power turbine (quasi-) isentropic processes. The results indicate that such a plant may reach efficiency levels above 30%, i.e. exceeding the efficiencies of the conventional Photovoltaic plants by a wide margin
Energy Technology Data Exchange (ETDEWEB)
He, Jiansen; Tu, Chuanyi; Wang, Linghua; Pei, Zhongtian [School of Earth and Space Sciences, Peking University, Beijing, 100871 (China); Marsch, Eckart [Institute for Experimental and Applied Physics, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel (Germany); Chen, Christopher H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Zhang, Lei [Sate Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China); Salem, Chadi S.; Bale, Stuart D., E-mail: jshept@gmail.com [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
2015-11-10
Magnetohydronamic turbulence is believed to play a crucial role in heating laboratory, space, and astrophysical plasmas. However, the precise connection between the turbulent fluctuations and the particle kinetics has not yet been established. Here we present clear evidence of plasma turbulence heating based on diagnosed wave features and proton velocity distributions from solar wind measurements by the Wind spacecraft. For the first time, we can report the simultaneous observation of counter-propagating magnetohydrodynamic waves in the solar wind turbulence. As opposed to the traditional paradigm with counter-propagating Alfvén waves (AWs), anti-sunward AWs are encountered by sunward slow magnetosonic waves (SMWs) in this new type of solar wind compressible turbulence. The counter-propagating AWs and SWs correspond, respectively, to the dominant and sub-dominant populations of the imbalanced Elsässer variables. Nonlinear interactions between the AWs and SMWs are inferred from the non-orthogonality between the possible oscillation direction of one wave and the possible propagation direction of the other. The associated protons are revealed to exhibit bi-directional asymmetric beams in their velocity distributions: sunward beams appear in short, narrow patterns and anti-sunward in broad extended tails. It is suggested that multiple types of wave–particle interactions, i.e., cyclotron and Landau resonances with AWs and SMWs at kinetic scales, are taking place to jointly heat the protons perpendicular and in parallel.
Smalyuk, V. A.; Robey, H. F.; Döppner, T.; Casey, D. T.; Clark, D. S.; Jones, O. S.; Milovich, J. L.; Peterson, J. L.; Bachmann, B.; Baker, K. L.; Benedetti, L. R.; Berzak Hopkins, L. F.; Bionta, R.; Bond, E.; Bradley, D. K.; Callahan, D. A.; Celliers, P. M.; Cerjan, C.; Chen, K.-C.; Goyon, C.; Grim, G.; Dixit, S. N.; Eckart, M. J.; Edwards, M. J.; Farrell, M.; Fittinghoff, D. N.; Frenje, J. A.; Gatu-Johnson, M.; Gharibyan, N.; Haan, S. W.; Hamza, A. V.; Hartouni, E.; Hatarik, R.; Havre, M.; Hohenberger, M.; Hoover, D.; Hurricane, O. A.; Izumi, N.; Jancaitis, K. S.; Khan, S. F.; Knauer, J. P.; Kroll, J. J.; Kyrala, G.; Lafortune, K. N.; Landen, O. L.; Ma, T.; MacGowan, B. J.; MacPhee, A. G.; Mauldin, M.; Merrill, F. E.; Moore, A. S.; Nagel, S.; Nikroo, A.; Pak, A.; Patel, P. K.; Ralph, J. E.; Sayre, D. B.; Shaughnessy, D.; Spears, B. K.; Tommasini, R.; Turnbull, D. P.; Velikovich, A. L.; Volegov, P. L.; Weber, C. R.; Widmayer, C. C.; Yeamans, C.
2016-10-01
Radiation-driven, layered deuterium-tritium (DT) implosions were carried out using 3-shock and 4-shock "adiabat-shaped" drives and plastic ablators on the National Ignition Facility (NIF) [E. M. Campbell et al., AIP Conf. Proc. 429, 3 (1998)]. The purpose of these shots was to gain further understanding on the relative performance of the low-foot implosions of the National Ignition Campaign [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] versus the subsequent high-foot implosions [T. Döppner et al., Phys. Rev. Lett. 115, 055001 (2015)]. The neutron yield performance in the experiment with the 4-shock adiabat-shaped drive was improved by factors ˜3 to ˜10, compared to five companion low-foot shots despite large low-mode asymmetries of DT fuel, while measured compression was similar to its low-foot companions. This indicated that the dominant degradation source for low-foot implosions was ablation-front instability growth, since adiabat shaping significantly stabilized this growth. For the experiment with the low-power 3-shock adiabat-shaped drive, the DT fuel compression was significantly increased, by ˜25% to ˜36%, compared to its companion high-foot implosions. The neutron yield increased by ˜20%, lower than the increase of ˜50% estimated from one-dimensional scaling, suggesting the importance of residual instabilities and asymmetries. For the experiment with the high-power, 3-shock adiabat-shaped drive, the DT fuel compression was slightly increased by ˜14% compared to its companion high-foot experiments. However, the compression was reduced compared to the lower-power 3-shock adiabat-shaped drive, correlated with the increase of hot electrons that hypothetically can be responsible for reduced compression in high-power adiabat-shaped experiments as well as in high-foot experiments. The total neutron yield in the high-power 3-shock adiabat-shaped shot N150416 was 8.5 × 1015 ± 0.2 × 1015, with the fuel areal density of 0.90 ± 0.07 g/cm2
Quantum adiabatic machine learning
Pudenz, Kristen L
2011-01-01
We develop an approach to machine learning and anomaly detection via quantum adiabatic evolution. In the training phase we identify an optimal set of weak classifiers, to form a single strong classifier. In the testing phase we adiabatically evolve one or more strong classifiers on a superposition of inputs in order to find certain anomalous elements in the classification space. Both the training and testing phases are executed via quantum adiabatic evolution. We apply and illustrate this approach in detail to the problem of software verification and validation.
Constitutive Equation Models of Hot-Compressed T122 Heat Resistant Steel
Institute of Scientific and Technical Information of China (English)
CA0Jin-rong; LIUZheng—dong; CHENGShi—chang; YANGGang; XIEJian-xin
2012-01-01
Based on dislocation reaction theory and Avrami equation, a constitutive equation model was developed to describe dynamic recovery and dynamic recrystallization during hot deformation of T122 heat resistant steel, which have taken the effect of dynamic strain aging into account. Uniaxial hot compression test had been carried out over a wide range of strain rate （0.01 to 10 s-1 ） and temperature （900 to 1 200 ~C） with the help of Gleeble 3500. Obtained experimental data was applied to determine the material parameters in proposed constitutive equations of T122 steel, by using the non-linear least square regress optimization method. The calculated constitutive equations are quantita- tively in good agreement with experimentally measured curves and microstructure observation. It shows that propose constitutive equation T122 steel is able to be used to predict flow stress of T122 steel during hot deformation in aus- tenite temperature scope.
Oreshkov, Ognyan
2010-01-01
We propose a theory of adiabaticity in quantum Markovian dynamics based on a structural decomposition of the Hilbert space induced by the asymptotic behavior of the Lindblad semigroup. A central idea of our approach is that the natural generalization of the concept of eigenspace of the Hamiltonian in the case of Markovian dynamics is a noiseless subsystem with a minimal noisy cofactor. Unlike previous attempts to define adiabaticity for open systems, our approach deals exclusively with physical entities and provides a simple, intuitive picture at the underlying Hilbert-space level, linking the notion of adiabaticity to the theory of noiseless subsystems. As an application of our theory, we propose a framework for decoherence-assisted computation in noiseless codes under general Markovian noise. We also formulate a dissipation-driven approach to holonomic computation based on adiabatic dragging of subsystems that is generally not achievable by non-dissipative means.
On The Strategies Towards Isothermal Gas Compression And Expansion
Heidari, Mahbod; Lemofouet, Sylvain; Rufer, Alfred
2014-01-01
Isothermal compression/expansion is regarded as the most promising process in many applications and many researchers and inventors have tried different methods to achieve this goal. The current article first studies the gradual roadmap from adiabatic towards isothermal process from thermodynamics and heat transfer point of view. Different strategies are investigated to achieve this goal by evaluating different possibilities; the bottleneck of the problem is then identified and then increment ...
Institute of Scientific and Technical Information of China (English)
Xiaoshu Tang; Zhao Guangjie; Nakao Tetsuya
2003-01-01
The recovery of compression set (RS) of wood after dry heating or steam treatment mainly depends on the temperature and time of treatment. For quantitative elucidation, a graph of intermediate RS was built with temperature (T) and time (t) as coordinates. In this graph (abbreviated as T-t planum), a series of curves of RS were created. This leads to a conclusion that same RS can be obtained by numerous different pathways. Further research on pathway equivalency based on T-t planum indicates that a low RS of 10% can be achieved definitely by different combinations of time and temperature. However, the fixation mechanism varies at different temperatures. On the equivalent pathways of higher recovery, the influence of temperature must be taken into consideration. The actual routes must be somewhat modified to achieve an expected result. This makes it possible for us to work out a best fixation pathway among all the possibilities, to eliminate the impact of heat on the mechanical properties of wood.
AB INITIO SIMULATIONS FOR MATERIAL PROPERTIES ALONG THE JUPITER ADIABAT
International Nuclear Information System (INIS)
We determine basic thermodynamic and transport properties of hydrogen-helium-water mixtures for the extreme conditions along Jupiter's adiabat via ab initio simulations, which are compiled in an accurate and consistent data set. In particular, we calculate the electrical and thermal conductivity, the shear and longitudinal viscosity, and diffusion coefficients of the nuclei. We present results for associated quantities like the magnetic and thermal diffusivity and the kinematic shear viscosity along an adiabat that is taken from a state-of-the-art interior structure model. Furthermore, the heat capacities, the thermal expansion coefficient, the isothermal compressibility, the Grüneisen parameter, and the speed of sound are calculated. We find that the onset of dissociation and ionization of hydrogen at about 0.9 Jupiter radii marks a region where the material properties change drastically. In the deep interior, where the electrons are degenerate, many of the material properties remain relatively constant. Our ab initio data will serve as a robust foundation for applications that require accurate knowledge of the material properties in Jupiter's interior, e.g., models for the dynamo generation.
Interplay between electric and magnetic effect in adiabatic polaritonic systems
Alabastri, Alessandro
2013-01-01
We report on the possibility of realizing adiabatic compression of polaritonic wave on a metallic conical nano-structure through an oscillating electric potential (quasi dynamic regime). By comparing this result with an electromagnetic wave excitation, we were able to relate the classical lighting-rod effect to adiabatic compression. Furthermore, we show that while the magnetic contribution plays a marginal role in the formation of adiabatic compression, it provides a blue shift in the spectral region. In particular, magnetic permeability can be used as a free parameter for tuning the polaritonic resonances. The peculiar form of adiabatic compression is instead dictated by both the source and the metal permittivity. The analysis is performed by starting from a simple electrostatic system to end with the complete electromagnetic one through intermediate situations such as the quasi-electrostatic and quasi-dynamic regimes. Each configuration is defined by a particular set of equations which allows to clearly determine the individual role played by the electric and magnetic contribution in the generation of adiabatic compression. We notice that these findings can be applied for the realization of a THz nano-metric generator. © 2013 Optical Society of America.
Directory of Open Access Journals (Sweden)
Shurayts Alexander
2016-01-01
Full Text Available Presents the results of studies of innovative materials in the field of renewable energy.The paper proposes a design and a formula for assessing energy efficiency of the heat pump air dryer, which uses zeotropic hydrocarbon mixtures of saturated hydrocarbons as a working agent and applies the principle of a counter-current heat exchanger with a variable temperature of both the working and the drying agents. Energy efficiency of the heat pump is achieved by means of obtaining a greater part of heat from renewable energy sources, in this case by cooling the air and condensing the water vapors in the heat pump. A conducted analysis identified correlations in establishing the marginal real coefficient of performance of the compression heat pump dryer running on zeotropic hydrocarbon mixtures and operating a cycle with variable temperatures of both the working and the drying agent in the evaporator and the condenser of the heat pump. According to the established correlations, the marginal real coefficient of performance of the compression heat pump dryers running on zeotropic hydrocarbon mixtures of 40 mol% of R600a and 60 mol% of R601 is 1.92 times higher than that of the same dryers running on only R600 (n-butane.
Internal heat exchange in an ejector-compression solar refrigeration system with R142b
Energy Technology Data Exchange (ETDEWEB)
Hernandez, Joge I; Estrada, Claudio A; Best, Roberto [Centro de Investigacion en Energia, UNAM, Temixco, Morelos (Mexico); Dorantes Ruben, J [Departamento de Energia, UNAM Azcapotzalco, Mexico, D.F. (Mexico)
2000-07-01
One way to use more efficiently the actual energy transfer in the ejector-compression system, is the use of heat exchangers between some of the components. The inclusion of two heat exchangers, preheater and precooler, is considered in a basic ejector-compression refrigeration system with refrigerant 142b. This study accounts for the energy and exergy efficiencies. COP and {epsilon}, according to parameter variations such as ejector efficiency, generation temperature with different superheating, condensation temperature and heat exchangers effectiveness. As known, the most important parameters in ejector-compression system analysis are the entrain-ment ratio U and system efficiencies COP and {epsilon}. The highest system COP and {epsilon}, as the entrainment ratio U, correspond to the highest exchangers effectiveness, highest superheating generator temperatures, highest ejector efficiency and lowest condenser temperature. For the COP and {epsilon} ratios, their maxima correspond to the same independent variables aforementioned for one of the higher superheating generator temperatures. In this case, this result indicates that the exergy efficiency {epsilon} does not contradict the information given by energy efficiency COP. So, to select correctly and optimum design condition, is enough to employ the COP ratio, which maximum value for the data shown corresponds to a superheating generator temperature of about 110 Celsius degrees, that can only be reached by evacuated tubular collectors or CPC solar concentrators. [Spanish] Una forma de usar mas eficientemente la transferencia real de energia en el sistema eyector-compresion es el uso de intercambiadores de calor entre algunos de los componentes. La inclusion de dos intercambiadores de calor precalentador y pre-enfriador se considera en un sistema de refrigeracion eyector-compresion con refrigerante 142b. Este estudio toma en cuenta las eficiencias de energia y exergia, COP y {epsilon}, de acuerdo con las variaciones
Energy Technology Data Exchange (ETDEWEB)
Batani, D.; Bernardinello, A.; Masella, V. [and others
1998-02-01
This report describes the experiment entitled 'Fast electron heating of shock compressed solids at high intensities relevant to fast ignition'; carried out at the Central Laser Facility (CLF) from the 5th January to the 15th February 1997. The experiment, funded by the Framework IV Large-Scale Facilities Access Scheme, was proposed by Dr. D. Batani, University of Milan, Italy and carried out by visiting researchers from the University and Ecole Polytechnique, Palaiseau, France. They were supported by UK researchers from the University of Essex, the University of Bristol and the Central Laser Facility, Rutherford Appleton Laboratory. Experimental results: (i) The experiment demonstrated the first results for fast electron deposition in compressed matter. The irradiances used in these experiments are lower than would be used in the fast ignitor scheme but the significance of the results is, nevertheless very relevant to this scheme. (ii) It is shown that in the experiments presented here that ionised, compressed plastic is less effective at stopping the fast electrons than uncompressed, unionised plastic. The stopping power of the compressed material is reduced by a factor of two (in areal density units) over the uncompressed materials. (iii) These experiments are the first measurements of electron stopping power in compressed plasmas but further experiments with more highly compressed plasmas are necessary before the results may be safely extrapolated to fast ignitor conditions. (author)
Scaling of Compressible Magnetohydrodynamic Turbulence in the Fast Solar Wind
Banerjee, S.; Hadid, L. Z.; Sahraoui, F.; Galtier, S.
2016-10-01
The role of compressible fluctuations in the energy cascade of fast solar wind turbulence is studied using a reduced form of an exact law derived recently for compressible isothermal magnetohydrodynamics and in situ observations from the THEMIS B/ARTEMIS P1 spacecraft. A statistical survey of the data revealed a turbulent energy cascade over a range of two decades of scales that is broader than the previous estimates made from an exact incompressible law. A term-by-term analysis of the compressible model reveals new insight into the role played by the compressible fluctuations in the energy cascade. The compressible fluctuations are shown to amplify by two to four times the turbulent cascade rate with respect to the incompressible model in ∼ 10 % of the analyzed samples. This new estimated cascade rate is shown to provide the adequate energy dissipation required to account for the local heating of the non-adiabatic solar wind.
Directory of Open Access Journals (Sweden)
Türker Dündar
2012-11-01
Full Text Available The effect of commercial heat treatment on physical and mechanical properties of compression wood (CW and opposite wood (OW of black pine (Pinus nigra Arnold was investigated. Black pine logs containing CW were cut parallel to the pith and separated into CW and OW sections. A commercial heat treatment process was applied to pine lumber at 180 and 210 ºC for 3 hours. Water absorption (WA, contact angle (CA, swelling, modulus of rupture (MOR, modulus of elasticity (MOE, and impact bending strength (IBS were measured. The results showed that heat treatment decreased water absorption and swelling of the CW and OW of black pine. Heat treatment at 210 °C temperature decreased the longitudinal swelling of CW by 51.4%. Higher immersion time lowered the effect of heat treatment on the WA values. The CA values of the CW and OW increased due to heat treatment. Heat treatment reduced the MOR, MOE, and IBS values. The results indicated that MOR, MOE, and CA values were highly affected in the CW; on the other hand, the IBS value was highly affected in the OW by heat treatment compared to control groups. The results indicate that heat-stabilized CW can be used more widely and effectively in the forest products industry.
Nickel Bubble Expansion in Type Ia Supernovae: Adiabatic Solutions
Wang, C Y
2006-01-01
We examine the expansion properties of the Nickel bubble in SNe Ia due to the radioactive heating from the 56Ni->56Co->56Fe decay sequence, under adiabatic, spherically symmetric approximation. We consider an exponentially -declining medium for the ejecta substrate, allowing for the density gradient as expected in a Type Ia supernova. The heating gives rise to an inflated Ni bubble, which induces a forward shock that compresses the outer ambient gas into a shell. As the heating saturates, the flow tends toward a freely-expanding state with the structure frozen into the ejecta. The thickness of the shell takes up ~ 100 in a narrow region limited by numerical resolution. The structure of the shell can be approximately described by a self-similar solution determined by its expansion rate and ambient density gradient. Compared to the case using a uniform-density medium, the density contrast of the inferred ejecta clumps is enhanced, while the interaction of the clumps with the remnant is deferred to a more advanc...
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Significant compressive stress may be induced in thin plate weldment by anti-welding heating treatment (AWHT)with a temperature difference above 350℃, and an interesting phenomenon of obvious residual stress reduction on non-treated surface was discovered. The method of AWHT has no great effect on the mechanical properties including hardness, strength and toughness of the metal material. The results in the paper prompt a possibility application in shipbuilding industry.
Institute of Scientific and Technical Information of China (English)
Wang Yi
2008-01-01
The zero dissipation limit of the compressible heat-conducting Navier-Stokes equations in the presence of the shock is investigated. It is shown that when the heat ε→ 0 (see (1.3)), if the solution of the corresponding Euler equations is piecewise smooth with shock wave satisfying the Lax entropy condition, then there exists a smooth solution to the Navier-Stokes equations, which converges to the piecewise smooth shock solution of the Euler equations away from the shock discontinuity at a rate of ε. The proof is given by a combination of the energy estimates and the matched asymptotic analysis introduced in [3].
Directory of Open Access Journals (Sweden)
Nattaporn Chaiyat
2014-11-01
Full Text Available In this study, simulation and experiment studies of a 10 kW solar H2O–LiBr absorption heat transformer (AHT integrating with a two-stage vapor compression heat pump (VCHP were carried out. The whole system was named as compression/absorption heat transformer (CAHT. The VCHP was used to recover rejected heat at the AHT condenser which was transferred back to the AHT evaporator at a higher temperature. The AHT unit took solar heat from a set of flat-plate solar collectors in parallel connection. R-134a and R-123 were refrigerants in the VCHP cycle. From the simulation, the total cycle coefficient (COP of the solar-CAHT was 0.71 compared with 0.49 of the normal solar-AHT. From the experiment, the total cycle COPs of the solar-CAHT and the solar-AHT were 0.62 and 0.39, respectively. The experimental results were lower than those of the simulated models due to the oversize of the experimental compressor. The annual expense of the solar-CAHT was found to be 5113 USD which was lower than 5418 USD of the solar-AHT. So it could be concluded that the modified unit was beneficial than the normal unit in terms of energy efficiency and economic expense.
Quantum Lubrication: Suppression of Friction in a First Principle Four Stroke Heat Engine
Feldmann, T; Feldmann, Tova; Kosloff, Ronnie
2005-01-01
A quantum model of a heat engine resembling the Otto cycle is employed to explore strategies to suppress frictional losses. These losses are caused by the inability of the engine's working medium to follow adiabatically the change in the Hamiltonian during the expansion and compression stages. By adding external noise to the engine, frictional losses can be suppressed.
Ghilvacs, M.; Prisecaru, T.; Pop, H.; Apostol, V.; Prisecaru, M.; Pop, E.; Popescu, Gh; Ciobanu, C.; Mohanad, A.; Alexandru, A.
2016-08-01
Compression ignition engines transform approximately 40% of the fuel energy into power available at the crankshaft, while the rest part of the fuel energy is lost as coolant, exhaust gases and other waste heat. An organic Rankine cycle (ORC) can be used to recover this waste heat. In this paper, the characteristics of a system combining a compression ignition engine with an ORC which recover the waste heat from the exhaust gases are analyzed. The performance map of the diesel engine is measured on an engine test bench and the heat quantities wasted by the exhaust gases are calculated over the engine's entire operating region. Based on this data, the working parameters of ORC are defined, and the performance of a combined engine-ORC system is evaluated across this entire region. The results show that the net power of ORC is 6.304kW at rated power point and a maximum of 10% reduction in brake specific fuel consumption can be achieved.
Joglekar, Archis; Thomas, Alec; Ridgers, Chris; Kingham, Rob
2015-11-01
In this study, we present full-scale 2D kinetic modeling of externally imposed magnetic fields on hohlraums with laser heating. We observe magnetic field cavitation and compression due to thermal energy transport. Self-consistent modeling of the electron momentum equation allows for a complete treatment of the heat flow equation and Ohm's Law. A complete Ohm's Law contains magnetic field advection through the Nernst mechanism that arises due to the heat flow. Magnetic field amplification by a factor of 3 occurs due to magnetic flux pile-up from Nernst convection. The magnetic field cavitates towards the hohlraum axis over a 0.5 ns time scale due to Nernst convection. This results in significantly different magnetic field profiles and slower cavitation than can be expected due to the plasma bulk flow. Non-local electrons contribute to the heat flow down the density gradient resulting in an augmented Nernst convection mechanism that is included self-consistently through kinetic modeling. In addition to showing the prevalence of non-local heat flows, we show effects such as anomalous heat flow up the density gradient induced by inverse bremsstrahlung heating. This research was supported by the DOE through Grant No. DE SC0010621 and in part through computational resources and services provided by Advanced Research Computing at the University of Michigan, Ann Arbor.
Operability Test Report for 241-T compressed air system and heat pump
International Nuclear Information System (INIS)
This Operability Test Report (OTR) documents the results of functional testing performed on the operating parameters of the 241-T-701 Compressed Air System. The System was successfully installed and tested per work package 2W-92-01172
Cai, Weizhao; Katrusiak, Andrzej
2014-01-01
Materials with negative linear compressibility are sought for various technological applications. Such effects were reported mainly in framework materials. When heated, they typically contract in the same direction of negative linear compression. Here we show that this common inverse relationship rule does not apply to a three-dimensional metal-organic framework crystal, [Ag(ethylenediamine)]NO3. In this material, the direction of the largest intrinsic negative linear compression yet observed in metal-organic frameworks coincides with the strongest positive thermal expansion. In the perpendicular direction, the large linear negative thermal expansion and the strongest crystal compressibility are collinear. This seemingly irrational positive relationship of temperature and pressure effects is explained and the mechanism of coupling of compressibility with expansivity is presented. The positive coupling between compression and thermal expansion in this material enhances its piezo-mechanical response in adiabatic process, which may be used for designing new artificial composites and ultrasensitive measuring devices. PMID:24993679
Reynard-Carette, C.; Lyoussi, A.; Brun, J.; Muraglia, M.; Carette, M.; Janulyte, A.; Zerega, Y.; André, J.; Bignan, G.; Chauvin, J.-P.; Fourmentel, D.; Gonnier, C.; Guimbal, P.; Malo, J.-Y.; Villard, J.-F.
2012-11-01
New online in-pile measurement methods are crucial during irradiations in Material Testing Reactors (MTR) for a better understanding of accelerated material ageing and nuclear fuel behaviour. In particular, instrumentation for measurements of one relevant parameter: nuclear heat deposition rate, called nuclear heating, has to be improved. The knowledge of this quantity is a great interest for various safety, scientist and end-user requirements (design of specific irradiation devices and associated cooling systems with imposed conditions). This paper focuses on thermal experimental and numerical studies carried out under non irradiation conditions on an in-pile calorimeter dedicated to nuclear heating quantification inside a new experimental device which will be dedicated to the experimental condition mapping (neutron and photon fluxes and nuclear heating) inside the JHR experimental channels. Experimental results concerning the calorimeter response during its electrical calibration (calorimeter design is compared to a single calorimeter which gives promising results (miniaturization, higher sensitivity).
Operability Test Report for 241-U Compressed Air System and heat pump
International Nuclear Information System (INIS)
The 241-U-701 compressed air system supplies instrument quality compressed air to Tank Farm 241-U. The system was upgraded. The operability test showed that the system operates within its intended design parameters. System performance was monitored, recorded, and used to identify areas of concern. Exceptions to the OTP and additional items for safe system performance were minimal and have been resolved; the air system is ready for Operation's use
Scaling of compressible magnetohydrodynamic turbulence in the fast solar wind
Sahraoui, F.; Banerjee, S.; Galtier, S.; Hadid, L.
2015-12-01
The role of compressible uctuations in the energy cascade of fast solar wind turbulence is studiedusing an exact law derived recently for compressible isothermal magnetohydrodynamics and in-situobservations of the THEMIS spacecraft. For the first time, a direct turbulent energy cascade isevidenced over three decades of scales which is signicantly broader than the previous estimatesmade from an exact incompressible law or from a compressible heuristic model. Unlike previousworks, our evaluation gives an energy ux which keeps a constant sign over the inertial range. Aterm-by-term analysis reveals that the dominant contribution to the energy ux comes from purecompressible uctuations. Furthermore, the compressible turbulent cascade rate is shown to providethe adequate energy dissipation required to account for the local heating of the non-adiabatic solarwind.
Energy Technology Data Exchange (ETDEWEB)
Sheng, L.Y., E-mail: lysheng@yeah.net [Peking University, Beijing 100871 (China); PKU-HKUST ShenZhen-Hong Kong Institution, Shenzhen 518057 (China); Xie, Y. [Hunan Electric Power Test and Research Institute, Changsha 410007 (China); Xi, T.F. [Peking University, Beijing 100871 (China); Guo, J.T. [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zheng, Y.F. [Peking University, Beijing 100871 (China); Ye, H.Q. [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)
2011-11-15
Highlights: {yields} The {alpha}-Cr, {sigma} and {mu} phases precipitate and form into network in as cast alloy. {yields} Rapid and intermediate cooling rate after solution treatment break the precipitates network; the lower cooling rate results in some {alpha}-Cr and Ni{sub 3}Al precipitates. {yields} Short-term aging results in massive Ni{sub 3}Al lathes and {alpha}-Cr particles, but long-term aging treatment coarsens the globule-shaped {alpha}-Cr particle and decreases the lath-shaped Ni{sub 3}Al, {mu} and {sigma} phase. {yields} The solid solution with short-term aging treatment improves mechanical properties of the alloy significantly. - Abstract: The alloy of Ni-Al26-Cr15-Co6-Ti3-Mo2-Nb0.5-Ho0.1 (at.%) was heat-treated and studied by microstructure examination and compressive test. The results reveal that in the as-cast alloy, {alpha}-Cr, {sigma} and {mu} phases are segregated along the NiAl phase boundary and form into network. Small Ni{sub 2}AlTi, Cr{sub 2}Nb and Ni{sub 2}Al{sub 3}Ho particles precipitate at NiAl grain boundary. The subsequent solid solution treatment with rapid and intermediate cooling rate transforms the net-like precipitating phases into discontinuous ones, but the rapid cooling leads to micro-cracks along phase boundary. However the lower cooling rate results in spherical {alpha}-Cr particle and needle-like Ni{sub 3}Al phase in NiAl matrix. The short-term aging after solid solution treatment promotes the coarsening of Ni{sub 3}Al lathes and {alpha}-Cr particles, and an orientation relationship of [001-bar]{sub {beta}}||[1-bar 10]{sub {lambda}{sup '}} and (1 1 0){sub {beta}}||(1 1 1){sub {gamma}'} is found between lath-shaped Ni{sub 3}Al phase and NiAl matrix. In addition, the {mu} phases are substituted by {sigma} and some Cr{sub 3}Ni{sub 2} phases. The long-term aging treatment reduces Ni{sub 3}Al, {sigma} and {mu} phases and coarsens the {alpha}-Cr phase further. The solid solution treatment and short-term aging improve the
Efficiency of Compressed Air Energy Storage
Elmegaard, Brian; Brix, Wiebke
2011-01-01
The simplest type of a Compressed Air Energy Storage (CAES) facility would be an adiabatic process consisting only of a compressor, a storage and a turbine, compressing air into a container when storing and expanding when producing. This type of CAES would be adiabatic and would if the machines were reversible have a storage efficiency of 100%. However, due to the specific capacity of the storage and the construction materials the air is cooled during and after compression in practice, making...
Ommen, Torben Schmidt; Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars; Elmegaard, Brian
2015-01-01
A large amount of operational and economic constraints limit the applicability of heat pumps operated with natural working fluids. The limitations are highly dependent on the integration of heat source and sink streams. An evaluation of feasible operating conditions was carried out considering the constraints of available refrigeration equipment and a requirement of a positive net present value of the investment. Six heat pump systems were considered, corresponding to an upper limit of the si...
ENTROPY-VORTEX WAVES IN NON-ADIABATIC FLOWS
Energy Technology Data Exchange (ETDEWEB)
Ibáñez S, Miguel H., E-mail: mhibanez@yahoo.com [Departamento de Ciencias Básicas, Facultad de Ingeniería, Universidad Autónoma del Caribe, Barranquilla (Colombia)
2016-02-20
The Ertel theorem on the vorticity along the flow of adiabatic fluids is generalized for non-adiabatic flows. Several limiting cases are analyzed and the results are applied to flows behind different hydrodynamics fronts, particularly to thermal fronts (heat and cooling fronts). An important conclusion of the present analysis is that vorticity is inherent in the condensation’s (or hot spots) formation by thermal instabilities in plasma flows. Implications for several astrophysical plasmas are outlined.
MICROSTRUCTURE IN ADIABATIC SHEAR BANDS IN A PEARLITIC ULTRAHIGH CARBON STEEL
Energy Technology Data Exchange (ETDEWEB)
Syn, C K; Lesuer, D R; Sherby, O D
2003-09-22
Adiabatic shear bands, obtained in compression deformation at a strain rate of 4000 s{sup -1}, in a pearlitic 1.3%C steel, were investigated. Shear-bands initiated at 55% compression deformation with the width of the band equal to 14 {micro}m. Nano-indentor hardness of the shear band was 11.5 GPa in contrast to the initial matrix hardness of 3.5 GPa. The high strength of the shear band is attributed to its creation from two sequential events. First, large strain deformation, at a high strain rate, accompanied by adiabatic heating, led to phase transformation to austenite. Second, retransformation upon rapid cooling occurred by a divorced eutectoid transformation. The result is a predicted microstructure consisting of nano-size carbide particles within a matrix of fine ferrite grains. It is proposed that the divorced eutectoid transformation occurs in iron-carbon steels during high rate deformation in ball milling, ball drop tests and in commercial wire drawing.
DEFF Research Database (Denmark)
Ommen, Torben Schmidt; Jensen, Jonas Kjær; Markussen, Wiebke Brix;
2015-01-01
A large amount of operational and economic constraints limit the applicability of heat pumps operated with natural working fluids. The limitations are highly dependent on the integration of heat source and sink streams. An evaluation of feasible operating conditions was carried out considering...... the constraints of available refrigeration equipment and a requirement of a positive net present value of the investment. Six heat pump systems were considered, corresponding to an upper limit of the sink temperature of 120 °C. For each set of heat sink and source temperatures the best available technology...... was determined. The results showed that four different heat pump systems propose the best available technology at different parts of the complete domain. Ammonia systems presented the best available technology at low sink outlet temperature. At high temperature difference between sink in- and outlet...
Nonresonance adiabatic photon trap
Popov, S S; Burdakov, A V; Ushkova, M Yu
2016-01-01
Concept of high efficiency photon storage based on adiabatic confinement between concave mirrors is presented and experimentally investigated. The approach is insensitive to typical for Fabri-Perot cells requirements on quality of accumulated radiation, tolerance of resonator elements and their stability. Experiments have been carried out with the trap, which consists from opposed concave cylindrical mirrors and conjugated with them spherical mirrors. In result, high efficiency for accumulation of radiation with large angular spread and spectrum width has been confirmed. As radiation source a commercial fiber laser has been used.
Institute of Scientific and Technical Information of China (English)
Zhensheng GAO; Zhong TAN; Guochun WU
2014-01-01
In this paper, we are concerned with the global existence and convergence rates of the smooth solutions for the compressible magnetohydrodynamic equations without heat conductivity, which is a hyperbolic-parabolic system. The global solutions are obtained by combining the local existence and a priori estimates if H3-norm of the initial perturbation around a constant states is small enough and its L1-norm is bounded. A priori decay-in-time estimates on the pressure, velocity and magnetic field are used to get the uniform bound of entropy. Moreover, the optimal convergence rates are also obtained.
Directory of Open Access Journals (Sweden)
J. D. Biamonte
2011-06-01
Full Text Available In his famous 1981 talk, Feynman proposed that unlike classical computers, which would presumably experience an exponential slowdown when simulating quantum phenomena, a universal quantum simulator would not. An ideal quantum simulator would be controllable, and built using existing technology. In some cases, moving away from gate-model-based implementations of quantum computing may offer a more feasible solution for particular experimental implementations. Here we consider an adiabatic quantum simulator which simulates the ground state properties of sparse Hamiltonians consisting of one- and two-local interaction terms, using sparse Hamiltonians with at most three-local interactions. Properties of such Hamiltonians can be well approximated with Hamiltonians containing only two-local terms. The register holding the simulated ground state is brought adiabatically into interaction with a probe qubit, followed by a single diabatic gate operation on the probe which then undergoes free evolution until measured. This allows one to recover e.g. the ground state energy of the Hamiltonian being simulated. Given a ground state, this scheme can be used to verify the QMA-complete problem LOCAL HAMILTONIAN, and is therefore likely more powerful than classical computing.
Directory of Open Access Journals (Sweden)
Fatih Yapıcı
2016-01-01
Full Text Available In this study, the compressive strength of heat treated Scotch Pine was modeled using artificial neural network. The compressive strength (CS value parallel to grain was determined after exposing the wood to heat treatment at temperature of 130, 145, 160, 175, 190 and 205ºC for 3, 6, 9, 12 hours. The experimental data was evaluated by using multiple variance analysis. Secondly, the effect of heat treatment on the CS of samples was modeled by using artificial neural network (ANN.
Energy Technology Data Exchange (ETDEWEB)
Jiang, Ming Liu; Wu, Jing Yi; Xu, Yu.Xiong; Wang, Ru Zhu [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China)
2010-11-15
The objective of this study is to evaluate the influence of condensing heat recovery on the dynamic behavior and performance of air conditioners. The article includes a test procedure utilized to evaluate the condensing heat recovery system, relevant experimental results, a detail analysis of the mechanisms, and improvement measure on such a system. The experimental results indicate that although the condensing heat recovery has a negative effect on the cooling capacity at the start of the heat recovery process, the average cooling coefficient of performance (COP) of the system can be improved. The study also incorporates a control scheme of the electronic expansion valve (EEV) of the condensing heat recovery system. The experimental comparison between the EEV and the thermostatic expansion valve (TEV) demonstrates that the EEV has better performance in both stability and efficiency in the condensing heat recovery system. (author)
Laser heating and magnetic compression of plasma in a fast solenoid
International Nuclear Information System (INIS)
A low-β plasma column a few mm in diameter by 22 cm in length is heated by an axially directed CO2 laser to a high-β state in a fast rising solenoidal field. Successful heating depends on proper timing between the laser pulse and rising field. Typical conditions attained are a line energy density of 6 J/cm, T-barapprox. =40 eV, and n/sub e/approx. =3 x 1017e-/cm3, with conditions quite uniform along the length. The heating suppresses instabilities which appear under certain conditions in the non-laser-heated case
Geometry of the Adiabatic Theorem
Lobo, Augusto Cesar; Ribeiro, Rafael Antunes; Ribeiro, Clyffe de Assis; Dieguez, Pedro Ruas
2012-01-01
We present a simple and pedagogical derivation of the quantum adiabatic theorem for two-level systems (a single qubit) based on geometrical structures of quantum mechanics developed by Anandan and Aharonov, among others. We have chosen to use only the minimum geometric structure needed for the understanding of the adiabatic theorem for this case.…
Directory of Open Access Journals (Sweden)
Vincentius Totok NOERWASITO
2016-08-01
Full Text Available Building materials have a major effect on the depletion of natural resources and energy in the world. Local raw materials are some of the best building materials, which can be found in every location; for example, compressed earth block and bamboo. This study adds to previous studies on compressed earth blocks without using combustion in the same location. The study focused on how to obtain a rural housing design by using compressed earth block walls and bamboo walls, which are adaptive to local materials and climate. Moreover, the ratio of the use of the compressed earth block walls with the walls is also examined to produce optimum embodied energy and heat energy buildings. The method used in this study was to analyze the characteristics of the compressed earth block and bamboo materials used as wall construction. While embodied energy and heat energy were calculated by using simulation model building, the heat energy calculation was found using the Archipak program. The results of the study shows that the optimum wall materials for the embodied energy and heat energy was compressed earth block with an area of 11 m2 and bamboo walls with an area of 19 m2.
Kawase, Tomoyuki; Kamiya, Mana; Kobayashi, Mito; Tanaka, Takaaki; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa
2015-05-01
Platelet-rich fibrin (PRF) was developed as an advanced form of platelet-rich plasma to eliminate xenofactors, such as bovine thrombin, and it is mainly used as a source of growth factor for tissue regeneration. Furthermore, although a minor application, PRF in a compressed membrane-like form has also been used as a substitute for commercially available barrier membranes in guided-tissue regeneration (GTR) treatment. However, the PRF membrane is resorbed within 2 weeks or less at implantation sites; therefore, it can barely maintain sufficient space for bone regeneration. In this study, we developed and optimized a heat-compression technique and tested the feasibility of the resulting PRF membrane. Freshly prepared human PRF was first compressed with dry gauze and subsequently with a hot iron. Biodegradability was microscopically examined in vitro by treatment with plasmin at 37°C or in vivo by subcutaneous implantation in nude mice. Compared with the control gauze-compressed PRF, the heat-compressed PRF appeared plasmin-resistant and remained stable for longer than 10 days in vitro. Additionally, in animal implantation studies, the heat-compressed PRF was observed at least for 3 weeks postimplantation in vivo whereas the control PRF was completely resorbed within 2 weeks. Therefore, these findings suggest that the heat-compression technique reduces the rate of biodegradation of the PRF membrane without sacrificing its biocompatibility and that the heat-compressed PRF membrane easily could be prepared at chair-side and applied as a barrier membrane in the GTR treatment.
Liu, Xianfeng; Yuan, Shengyang; Sieffert, Yannick; Fityus, Stephen; Buzzi, Olivier
2016-08-01
This study falls in the context of underground coal fires where burning coal can elevate the temperature of a rock mass in excess of 1000°. The objective of the research is to experimentally characterize the change in mechanical behaviour, mineralogy and microstructural texture of two sedimentary rocks when subjected to temperatures up to 1200 °C for 24 h. Specimens of local sandstone and mudstone were comprehensively characterized by X-ray diffraction and thermal-gravimetric analysis. These analyses were complemented by optical microscopy and scanning electron microscopy on polished thin sections. In addition, pore size distributions of these heated rocks were inferred by means of mercury intrusion porosimetry. These results were extended to an estimation of the intrinsic permeability using the Katz-Thompson model. Investigations at micro scale were followed by mechanical testing (both unconfined and confined compression tests) on cylindrical specimens of heated rocks. Results show that the unconfined compressive strength (UCS) of both rock types tends to increase when the temperatures increases up to 900 °C, beyond which the UCS tends to slightly decrease. As for the permeability, a clear increase in intrinsic permeability was observed for both rocks. The macroscopic behaviour was found to be fully consistent with the changes observed at micro scale.
Internal (Annular) and Compressible External (Flat Plate) Turbulent Flow Heat Transfer Correlations.
Energy Technology Data Exchange (ETDEWEB)
Dechant, Lawrence [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, Justin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2016-01-01
Here we provide a discussion regarding the applicability of a family of traditional heat transfer correlation based models for several (unit level) heat transfer problems associated with flight heat transfer estimates and internal flow heat transfer associated with an experimental simulation design (Dobranich 2014). Variability between semi-empirical free-flight models suggests relative differences for heat transfer coefficients on the order of 10%, while the internal annular flow behavior is larger with differences on the order of 20%. We emphasize that these expressions are strictly valid only for the geometries they have been derived for e.g. the fully developed annular flow or simple external flow problems. Though, the application of flat plate skin friction estimate to cylindrical bodies is a traditional procedure to estimate skin friction and heat transfer, an over-prediction bias is often observed using these approximations for missile type bodies. As a correction for this over-estimate trend, we discuss a simple scaling reduction factor for flat plate turbulent skin friction and heat transfer solutions (correlations) applied to blunt bodies of revolution at zero angle of attack. The method estimates the ratio between axisymmetric and 2-d stagnation point heat transfer skin friction and Stanton number solution expressions for sub-turbulent Reynolds numbers %3C1x10 4 . This factor is assumed to also directly influence the flat plate results applied to the cylindrical portion of the flow and the flat plate correlations are modified by
Thermoelectric Effects under Adiabatic Conditions
Directory of Open Access Journals (Sweden)
George Levy
2013-10-01
Full Text Available This paper investigates not fully explained voltage offsets observed by several researchers during the measurement of the Seebeck coefficient of high Z materials. These offsets, traditionally attributed to faulty laboratory procedures, have proven to have an irreducible component that cannot be fully eliminated in spite of careful laboratory procedures. In fact, these offsets are commonly observed and routinely subtracted out of commercially available Seebeck measurement systems. This paper offers a possible explanation based on the spontaneous formation of an adiabatic temperature gradient in the presence of a force field. The diffusion-diffusion heat transport mechanism is formulated and applied to predict two new thermoelectric effects. The first is the existence of a temperature gradient across a potential barrier in a semiconductor and the second is the Onsager reciprocal of the first, that is, the presence of a measureable voltage that arises across a junction when the temperature gradient is forced to zero by a thermal clamp. Suggested future research includes strategies for utilizing the new thermoelectric effects.
Curry, D. M.; Cox, J. E.
1972-01-01
Coupled nonlinear partial differential equations describing heat and mass transfer in a porous matrix are solved in finite difference form with the aid of a new iterative technique (the strongly implicit procedure). Example numerical results demonstrate the characteristics of heat and mass transport in a porous matrix such as a charring ablator. It is emphasized that multidimensional flow must be considered when predicting the thermal response of a porous material subjected to nonuniform boundary conditions.
Design Point for a Spheromak Compression Experiment
Woodruff, Simon; Romero-Talamas, Carlos A.; O'Bryan, John; Stuber, James; Darpa Spheromak Team
2015-11-01
Two principal issues for the spheromak concept remain to be addressed experimentally: formation efficiency and confinement scaling. We are therefore developing a design point for a spheromak experiment that will be heated by adiabatic compression, utilizing the CORSICA and NIMROD codes as well as analytic modeling with target parameters R_initial =0.3m, R_final =0.1m, T_initial =0.2keV, T_final =1.8keV, n_initial =1019m-3 and n_final = 1021m-3, with radial convergence of C =3. This low convergence differentiates the concept from MTF with C =10 or more, since the plasma will be held in equilibrium throughout compression. We present results from CORSICA showing the placement of coils and passive structure to ensure stability during compression, and design of the capacitor bank needed to both form the target plasma and compress it. We specify target parameters for the compression in terms of plasma beta, formation efficiency and energy confinement. Work performed under DARPA grant N66001-14-1-4044.
Institute of Scientific and Technical Information of China (English)
WANG Xue-bin
2008-01-01
The coexistent phenomenon of deformed and transformed adiabatic shear bands(ASBs) of ductile metal was analyzed using the JOHNSON-COOK model and gradient-dependent plasticity(GDP). The effects of melting point, density, heat capacity and work to heat conversion factor were investigated. Higher work to heat conversion factor, lower density, lower heat capacity and higher melting point lead to wider transformed ASB and higher local plastic shear deformation between deformed and transformed ASBs. Higher work to heat conversion factor, lower density, lower heat capacity and lower melting point cause higher local plastic shear deformation in the deformed ASB. Three reasons for the scatter in experimental data on the ASB width were pointed out and the advantages of the work were discussed. If the transformed ASB width is used to back-calculate the internal length parameter in the GDP, undoubtedly, the parameter will be extremely underestimated.
Numerical solution of non-isothermal non-adiabatic flow of real gases in pipelines
Bermúdez, Alfredo; López, Xián; Vázquez-Cendón, M. Elena
2016-10-01
A finite volume scheme for the numerical solution of a mathematical model for non-isothermal non-adiabatic compressible flow of a real gas in a pipeline is introduced. In order to make an upwind discretization of the flux, the Q-scheme of van Leer is used. Unlike standard Euler equations, the model takes into account wall friction, variable height and heat transfer between the pipe and the environment. Since all these terms are sources, in order to get a well-balanced scheme they are discretized by making a similar upwinding to the one in the flux term. The performance of the overall method has been shown for some usual numerical tests. The final goal, which is beyond the scope of this paper, is to consider a network including several pipelines connected at junctions, as those employed for natural gas transport.
Multiplicity features of adiabatic autothermal reactors
Energy Technology Data Exchange (ETDEWEB)
Lovo, M.; Balakotaiah, V. (Houston Univ., TX (United States). Dept. of Chemical Engineering)
1992-01-01
In this paper singularity theory, large activation energy asymptotic, and numerical methods are used to present a comprehensive study of the steady-state multiplicity features of three classical adiabatic autothermal reactor models: tubular reactor with internal heat exchange, tubular reactor with external heat exchange, and the CSTR with external heat exchange. Specifically, the authors derive the exact uniqueness-multiplicity boundary, determine typical cross-sections of the bifurcation set, and classify the different types of bifurcation diagrams of conversion vs. residence time. Asymptotic (limiting) models are used to determine analytical expressions for the uniqueness boundary and the ignition and extinction points. The analytical results are used to present simple, explicit and accurate expressions defining the boundary of the region of autothermal operation in the physical parameter space.
Modeling and Simulation of Radiative Compressible Flows in Aerodynamic Heating Arc-Jet Facility
Bensassi, Khalil; Laguna, Alejandro A.; Lani, Andrea; Mansour, Nagi N.
2016-01-01
Numerical simulations of an arc heated flow inside NASA's 20 [MW] Aerodynamics heating facility (AHF) are performed in order to investigate the three-dimensional swirling flow and the current distribution inside the wind tunnel. The plasma is considered in Local Thermodynamics Equilibrium(LTE) and is composed of Air-Argon gas mixture. The governing equations are the Navier-Stokes equations that include source terms corresponding to Joule heating and radiative cooling. The former is obtained by solving an electric potential equation, while the latter is calculated using an innovative massively parallel ray-tracing algorithm. The fully coupled system is closed by the thermodynamics relations and transport properties which are obtained from Chapman-Enskog method. A novel strategy was developed in order to enable the flow solver and the radiation calculation to be preformed independently and simultaneously using a different number of processors. Drastic reduction in the computational cost was achieved using this strategy. Details on the numerical methods used for space discretization, time integration and ray-tracing algorithm will be presented. The effect of the radiative cooling on the dynamics of the flow will be investigated. The complete set of equations were implemented within the COOLFluiD Framework. Fig. 1 shows the geometry of the Anode and part of the constrictor of the Aerodynamics heating facility (AHF). Fig. 2 shows the velocity field distribution along (x-y) plane and the streamline in (z-y) plane.
Performance Analysis of Stirling Engine-Driven Vapor Compression Heat Pump System
Kagawa, Noboru
Stirling engine-driven vapor compression systems have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration which can play an important role in alleviating environmental and energy problems. This paper introduces a design method for the systems based on reliable mathematical methods for Stirling and Rankin cycles using reliable thermophysical information for refrigerants. The model deals with a combination of a kinematic Stirling engine and a scroll compressor. Some experimental coefficients are used to formulate the model. The obtained results show the performance behavior in detail. The measured performance of the actual system coincides with the calculated results. Furthermore, the calculated results clarify the performance using alternative refrigerants for R-22.
Energy Technology Data Exchange (ETDEWEB)
Sironi, Lorenzo [NASA Einstein Postdoctoral Fellow. (United States); Narayan, Ramesh, E-mail: lsironi@cfa.harvard.edu, E-mail: rnarayan@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2015-02-20
In systems accreting well below the Eddington rate, such as the central black hole in the Milky Way (Sgr A*), the plasma in the innermost regions of the disk is believed to be collisionless and have two temperatures, with the ions substantially hotter than the electrons. However, whether a collisionless faster-than-Coulomb energy transfer mechanism exists in two-temperature accretion flows is still an open question. We study the physics of electron heating during the growth of ion velocity-space instabilities by means of multidimensional, fully kinetic, particle-in-cell (PIC) simulations. A background large-scale compression—embedded in a novel form of the PIC equations—continuously amplifies the field. This constantly drives a pressure anisotropy P > P {sub ∥} because of the adiabatic invariance of the particle magnetic moments. We find that, for ion plasma beta values β{sub 0i} ∼ 5-30 appropriate for the midplane of low-luminosity accretion flows (here, β{sub 0i} is the ratio of ion thermal pressure to magnetic pressure), mirror modes dominate if the electron-to-proton temperature ratio is T {sub 0e}/T {sub 0i} ≳ 0.2, whereas for T {sub 0e}/T {sub 0i} ≲ 0.2 the ion cyclotron instability triggers the growth of strong Alfvén-like waves, which pitch-angle scatter the ions to maintain marginal stability. We develop an analytical model of electron heating during the growth of the ion cyclotron instability, which we validate with PIC simulations. We find that for cold electrons (β{sub 0e} ≲ 2 m{sub e} /m{sub i} , where β{sub 0e} is the ratio of electron thermal pressure to magnetic pressure), the electron energy gain is controlled by the magnitude of the E-cross-B velocity induced by the ion cyclotron waves. This term is independent of the initial electron temperature, so it provides a solid energy floor even for electrons starting with extremely low temperatures. On the other hand, the electron energy gain for β{sub 0e} ≳ 2 m{sub e} /m{sub i}
DelVescovo, Dan A.
Low temperature combustion strategies have demonstrated high thermal efficiency with low emissions of pollutants, including oxides of nitrogen and particulate matter. One such combustion strategy, called Reactivity Controlled Compression Ignition (RCCI), which involves the port injection of a low reactivity fuel such as gasoline, ethanol, or natural gas, and a direct injection of a high reactivity fuel, such as diesel, has demonstrated excellent control over the heat release event due to the introduction of in-cylinder stratification of equivalence ratio and reactivity. The RCCI strategy is inherently fuel flexible, however the direct injection strategy needs to be tailored to the combination of premixed and direct injected fuels. Experimental results demonstrate that, when comparing different premixed fuels, matching combustion phasing with premixed mass percentage or SOI timing is not sufficient to retain baseline efficiency and emissions results. If the bulk characteristics of the heat release event can be matched, however, then the efficiency and emissions can be maintained. A 0-D methodology for predicting the required fuel stratification for a desired heat release for kinetically-controlled stratified-charge combustion strategies is proposed and validated with 3-D reacting and non-reacting CFD simulations performed with KIVA3Vr2 in this work. Various heat release rate shapes, phasing, duration, and premixed and DI fuel chemistries are explored using this analysis. This methodology provides a means by which the combustion process of a stratified-charge, kinetically-controlled combustion strategy could be optimized for any fuel combination, assuming that the fuel chemistry is well characterized.
Taira, Shigeharu; Yazima, Ryuzaburo; Tarutani, Isamu; Koyama, Shigeru
This paper deals with an experimental study on the performance evaluation of heat pump systems using HFC alternative refrigerants. The tested heat pump systems are modified from the R22 use to alternative refrigerants. Refrigerant mixtures of R410A, R407C. R32/125 and R32/134a are tested. where R410A and R407C launched into global market recently. Pure refrigerants of R22, R32, R125 and R134a are also tested. The experimental results of alternative refrigerants are evaluated in comparison with the result of R22, and the following are confirmed : (1) the performance of R32 is the highest. (2) adding R125 to R32 and R32/134a results into the deterioration of the performance, (3) the use of counter flow-like heat exchangers for a zeotropic refrigerant mixtures are effective, and (4) in case of R410A. the modification of the compressor to fit operating pressure heightens the performance. The effects of the performance of components on the COP are also analyzed based on the measured thermodynamic states at both ends of components in the system. Then, it is clarified that the most effective factor is irreversibility of compressors and the following is the pressure drop in low pressure side including the evaporator and the suction pipe.
Linear response of galactic halos to adiabatic gravitational perturbations
Murali, Chigurupati; Tremaine, Scott
1997-01-01
We determine the response of a self-similar isothermal stellar system to small adiabatic gravitational perturbations. For odd spherical harmonics, the response is identical to the response of the analogous isothermal fluid system. For even spherical harmonics, the response can be regarded as an infinite series of wavetrains in $\\log r$, implying alternating compression and rarefaction in equal logarithmic radius intervals. Partly because of the oscillatory nature of the solutions, tidal field...
The density variance - Mach number relation in isothermal and non-isothermal adiabatic turbulence
Nolan, Chris A; Sutherland, Ralph S
2015-01-01
The density variance - Mach number relation of the turbulent interstellar medium is relevant for theoretical models of the star formation rate, efficiency, and the initial mass function of stars. Here we use high-resolution hydrodynamical simulations with grid resolutions of up to 1024^3 cells to model compressible turbulence in a regime similar to the observed interstellar medium. We use Fyris Alpha, a shock-capturing code employing a high-order Godunov scheme to track large density variations induced by shocks. We investigate the robustness of the standard relation between the logarithmic density variance (sigma_s^2) and the sonic Mach number (M) of isothermal interstellar turbulence, in the non-isothermal regime. Specifically, we test ideal gases with diatomic molecular (gamma = 7/5) and monatomic (gamma = 5/3) adiabatic indices. A periodic cube of gas is stirred with purely solenoidal forcing at low wavenumbers, leading to a fully-developed turbulent medium. We find that as the gas heats in adiabatic comp...
Adiabatic cooling of solar wind electrons
Sandbaek, Ornulf; Leer, Egil
1992-01-01
In thermally driven winds emanating from regions in the solar corona with base electron densities of n0 not less than 10 exp 8/cu cm, a substantial fraction of the heat conductive flux from the base is transfered into flow energy by the pressure gradient force. The adiabatic cooling of the electrons causes the electron temperature profile to fall off more rapidly than in heat conduction dominated flows. Alfven waves of solar origin, accelerating the basically thermally driven solar wind, lead to an increased mass flux and enhanced adiabatic cooling. The reduction in electron temperature may be significant also in the subsonic region of the flow and lead to a moderate increase of solar wind mass flux with increasing Alfven wave amplitude. In the solar wind model presented here the Alfven wave energy flux per unit mass is larger than that in models where the temperature in the subsonic flow is not reduced by the wave, and consequently the asymptotic flow speed is higher.
Institute of Scientific and Technical Information of China (English)
张凯; 张路青
2011-01-01
揭示了可以展现垂直高速飞行的飞片在碰撞目的物的瞬间会产生极高速气流的聚能效应现象.在一般的爆炸压实实验中,飞片下的空间都是大气状态下的空气,空气量都很少,不会超过1 g,但在飞片高速飞行状态下,大多数气体很难向四周排出,最后形成绝热压缩气体,气流以万米/秒以上高速向四周喷射在出能量可切断很厚的钢板.这是从未被注意过的、可能也是不寻常的重要实验结果.%This paper reveals the phenomenon of the accumulating energy effect of high velocity airflow which is emerged by shooting practice from a vertical flying plate in twinkling of attack. In general experiments of explosive compression, the air space under the flying plate is atmospherical air, its quantity is a little, not more than one gram. But in the high velocity fling state of the flying plate, the vast majority of air is difficult to exhaust towards all around, at last to form the adiabatic compression air spurt out around with the velocity more than ten kilometers per second, it may cut off a much thick steel plate. This is an unusual experimental result which is not yet noticed by majority of research scholars.
Adiabatic theory for the bipolaron
Energy Technology Data Exchange (ETDEWEB)
Lakhno, V.D. (Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino Moscow Region, 142292 (Russian Federation))
1995-02-01
A translation-invariant adiabatic theory is constructed for the bipolaron. It is shown that motions in the bipolaron are divided: the relative electron coordinates describe fast electron oscillations in the induced polarization well and the center of mass coordinates represent slow electron movement followed by polarization. Nonlinear differential bipolaron equations are derived which are asymptotically exact in the adiabatic limit. Particlelike solutions of these equations correspond to the bipolaron bound state. The exact solution yields the value of the ion critical parameter [eta]=0.31 for which the bipolaron state is stable, where [eta]=[epsilon][sub [infinity
Optimizing adiabaticity in quantum mechanics
MacKenzie, R; Renaud-Desjardins, L
2011-01-01
A condition on the Hamiltonian of a time-dependent quantum mechanical system is derived which, if satisfied, implies optimal adiabaticity (defined below). The condition is expressed in terms of the Hamiltonian and in terms of the evolution operator related to it. Since the latter depends in a complicated way on the Hamiltonian, it is not yet clear how the condition can be used to extract useful information about the optimal Hamiltonian. The condition is tested on an exactly-soluble time-dependent problem (a spin in a magnetic field), where perfectly adiabatic evolution can be easily identified.
Elementary examples of adiabatic invariance
Energy Technology Data Exchange (ETDEWEB)
Crawford, F.S. (Physics Department, University of California, Berkeley, CA (USA) Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720 (USA))
1990-04-01
Simple classical one-dimensional systems subject to adiabatic (gradual) perturbations are examined. The first examples are well known: the adiabatic invariance of the product {ital E}{tau} of energy {ital E} and period {tau} for the simple pendulum and for the simple harmonic oscillator. Next, the adiabatic invariants of the vertical bouncer are found---a ball bouncing elastically from the floor of a rising elevator having slowly varying velocity and acceleration. These examples lead to consideration of adiabatic invariance for one-dimensional systems with potentials of the form {ital V}={ital ax}{sup {ital n}}, with {ital a}={ital a}({ital t}) slowly varying in time. Then, the horizontal bouncer is considered---a mass sliding on a smooth floor, bouncing back and forth between two impenetrable walls, one of which is slowly moving. This example is generalized to a particle in a bound state of a general potential with one slowly moving turning point.'' Finally, circular motion of a charged particle in a magnetic field slowly varying in time under three different configurations is considered: (a) a free particle in a uniform field; (b) a free particle in a nonuniform betatron'' field; and (c) a particle constrained to a circular orbit in a uniform field.
Transitionless driving on adiabatic search algorithm
Energy Technology Data Exchange (ETDEWEB)
Oh, Sangchul, E-mail: soh@qf.org.qa [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Kais, Sabre, E-mail: kais@purdue.edu [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Department of Chemistry, Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)
2014-12-14
We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.
Digital Waveguide Adiabatic Passage Part 1: Theory
Vaitkus, Jesse A; Greentree, Andrew D
2016-01-01
Spatial adiabatic passage represents a new way to design integrated photonic devices. In conventional adiabatic passage designs require smoothly varying waveguide separations. Here we show modelling of adiabatic passage devices where the waveguide separation is varied digitally. Despite digitisation, our designs show robustness against variations in the input wavelength and refractive index contrast of the waveguides relative to the cladding. This approach to spatial adiabatic passage opens new design strategies and hence the potential for new photonics devices.
New Regenerative Cycle for Vapor Compression Refrigeration
Energy Technology Data Exchange (ETDEWEB)
Mark J. Bergander
2005-08-29
The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient of performance for geothermal heat pumps based on a new regenerative thermodynamic cycle as comparing to existing technology. In order to demonstrate the improved performance of the prototype, it will be compared to published parameters of commercially available geothermal heat pumps manufactured by US and foreign companies. Other objectives are to optimize the design parameters and to determine the economic viability of the new technology. Background (as stated in the proposal): The proposed technology closely relates to EERE mission by improving energy efficiency, bringing clean, reliable and affordable heating and cooling to the residential and commercial buildings and reducing greenhouse gases emission. It can provide the same amount of heating and cooling with considerably less use of electrical energy and consequently has a potential of reducing our nations dependence on foreign oil. The theoretical basis for the proposed thermodynamic cycle was previously developed and was originally called a dynamic equilibrium method. This theory considers the dynamic equations of state of the working fluid and proposes the methods for modification of T-S trajectories of adiabatic transformation by changing dynamic properties of gas, such as flow rate, speed and acceleration. The substance of this proposal is a thermodynamic cycle characterized by the regenerative use of the potential energy of two-phase flow expansion, which in traditional systems is lost in expansion valves. The essential new features of the process are: (1) The application of two-step throttling of the working fluid and two-step compression of its vapor phase. (2) Use of a compressor as the initial step compression and a jet device as a second step, where throttling and compression are combined. (3) Controlled ratio of a working fluid at the first and
On the persistence of adiabatic shear bands
Directory of Open Access Journals (Sweden)
Bassim M.N.
2012-08-01
Full Text Available It is generally agreed that the initiation and development of adiabatic shear bands (ASBs are manifestations of damage in metallic materials subjected to high strain rates and large strains as those due to impact in a Hopkinson Bar system. Models for evolution of these bands have been described in the literature. One question that has not received attention is how persistent these bands are and whether their presence and effect can be reversed or eliminated by using a process of thermal (heat treatment or thermo-mechanical treatment that would relieve the material from the high strain associated with ASBs and their role as precursors to crack initiation and subsequent failure. Since ASBs are more prevalent and more defined in BCC metals including steels, a study was conducted to investigate the best conditions of generating ASBs in a heat treatable steel, followed by determining the best conditions for heat treatment of specimens already damaged by the presence of ASBs in order to relieve the strains due to ASBs and restore the material to an apparent microstructure without the “scars” due to the previous presence of ASBs. It was found that heat treatment achieves the curing from ASBs. This presentation documents the process undertaken to achieve this objective.
Improved Refrigerant Characteristics Flow Predictions in Adiabatic Capillary Tube
Directory of Open Access Journals (Sweden)
Shodiya Sulaimon
2012-07-01
Full Text Available This study presents improved refrigerant characteristics flow predictions using homogenous flow model in adiabatic capillary tube, used in small vapor compression refrigeration system. The model is based on fundamental equations of mass, momentum and energy. In order to improve the flow predictions, the inception of vaporization in the capillary tube is determined by evaluating initial vapor quality using enthalpy equation of refrigerant at saturation point and the inlet entrance effect of the capillary tube is also accounted for. Comparing this model with experimental data from open literature showed a reasonable agreement. Further comparison of this new model with earlier model of Bansal showed that the present model could be use to improve the performance predictions of refrigerant flow in adiabatic capillary tube.
Parametric Erosion Investigation: Propellant Adiabatic Flame Temperature
Directory of Open Access Journals (Sweden)
P. J. Conroy
2002-01-01
Full Text Available The influence of quasi-independent parameters and their potential influence on erosion in guns have been investigated. Specifically, the effects of flame temperature and the effect of assuming that the Lewis number (ratio of mass-to-heat transport to the surface, Le = 1, has been examined. The adiabatic flame temperature for a propellant was reduced by the addition of a diluent from a high temperature of 3843 K (similar to that of M9 down to 3004 K, which is near the value for M30A1 propellant. Mass fractions of critical species at the surface with and without the assumption of Le = 1 are presented, demonstrating that certain species preferentially reach the surface providing varied conditions for the surface reactions. The results for gun tube bore surface regression qualitatively agree with previous studies and with current experimental data.
Energy Technology Data Exchange (ETDEWEB)
Witte, H.; Strunkheide, J.; Eckhardt, R.
2001-01-01
Heat is removed from the compressed air of the activation tanks via a separate air cooler installed in the compressed-air line leading to the activation tank. The heat recovered will heat up the sludge in the digestion tank or will be fed into the heating system of the plant. The following goals are defined: Savings of heating oil; Saving of digestion gas as completely as possible; Power generation from the saved gas in a cogeneration unit; Power supply to the public grid. [German] Zielsetzung des Pilotprojektes ist die Nutzung der Druckluftwaerme von Belebungsanlagen als eine Moeglichkeit der Energieeinsparung auf Klaeranlagen. Die Nutzung der Verlustwaerme soll durch Abgriff der Waerme ueber einen separaten Luftkuehler erfolgen, der direkt in der Druckluftleitung zum Belebungsbecken installiert ist. Die auf diese Weise zurueckgewonnene Waerme soll zur Rohschlammaufheizung im Faulungsprozess dienen bzw. in das Betriebsheizungssystem eingespeist werden. Somit koennen folgende Ziele der Waermerueckgewinnungsanlage ins Auge gefasst werden: - Einsparung von Heizoel zu Heizzwecken in den Betriebsanlagen der Klaeranlage - Moeglichst komplette Einsparung von Faulgas im Heizkessel daraus folgend: - Mehrverstromung der im Heizkessel weniger verbrauchten Gasmengen im Blockheizkraftwerk (BHKW) mit dem Ergebnis: - Wirtschaftlicher Ertrag durch Einspeisung dieser Mehrmengen an Strom in das oeffentliche Versorgungsnetz. (orig.)
Performance of indirectly driven capsule implosions on NIF using adiabat-shaping
Robey, H. F.; Smalyuk, V. A.; Milovich, J. L.; Döppner, T.; Casey, D. T.; Baker, K. L.; Peterson, J. L.; Bachmann, B.; Berzak Hopkins, L. F.; Bond, E.; Caggiano, J. A.; Callahan, D. A.; Celliers, P. M.; Cerjan, C.; Clark, D. S.; Dixit, S. N.; Edwards, M. J.; Gharibyan, N.; Haan, S. W.; Hammel, B. A.; Hamza, A. V.; Hatarik, R.; Hurricane, O. A.; Jancaitis, K. S.; Jones, O. S.; Kerbel, G. D.; Kroll, J. J.; Lafortune, K. N.; Landen, O. L.; Ma, T.; Marinak, M. M.; MacGowan, B. J.; MacPhee, A. G.; Pak, A.; Patel, M.; Patel, P. K.; Perkins, L. J.; Sayre, D. B.; Sepke, S. M.; Spears, B. K.; Tommasini, R.; Weber, C. R.; Widmayer, C. C.; Yeamans, C.; Giraldez, E.; Hoover, D.; Nikroo, A.; Hohenberger, M.; Gatu Johnson, M.
2016-05-01
A series of indirectly driven capsule implosions has been performed on the National Ignition Facility to assess the relative contributions of ablation-front instability growth vs. fuel compression on implosion performance. Laser pulse shapes for both low and high-foot pulses were modified to vary ablation-front growth & fuel adiabat, separately and controllably. Two principal conclusions are drawn from this study: 1) It is shown that an increase in laser picket energy reduces ablation-front instability growth in low-foot implosions resulting in a substantial (3-10X) increase in neutron yield with no loss of fuel compression. 2.) It is shown that a decrease in laser trough power reduces the fuel adiabat in high-foot implosions results in a significant (36%) increase in fuel compression together with no reduction in neutron yield. These results taken collectively bridge the space between the higher compression low-foot results and the higher yield high-foot results.
Design of the PIXIE Adiabatic Demagnetization Refrigerators
Shirron, Peter J.; Kimball, Mark Oliver; Fixsen, Dale J.; Kogut, Alan J.; Li, Xiaoyi; DiPirro, Michael
2012-01-01
The Primordial Inflation Explorer (PIXIE) is a proposed mission to densely map the polarization of the cosmic microwave background. It will operate in a scanning mode from a sun-synchronous orbit, using low temperature detectors (at 0.1 K) and located inside a teslescope that is cooled to approximately 2.73 K - to match the background temperature. A mechanical cryocooler operating at 4.5 K establishes a low base temperature from which two adiabatic demagnetization refrigerator (ADR) assemblies will cool the telescope and detectors. To achieve continuous scanning capability, the ADRs must operate continuously. Complicating the design are two factors: 1) the need to systematically vary the temperature of various telescope components in order to separate the small polarization signal variations from those that may arise from temperature drifts and changing gradients within the telescope, and 2) the orbital and monthly variations in lunar irradiance into the telescope barrels. These factors require the telescope ADR to reject quasi-continuous heat loads of 2-3 millwatts, while maintaining a peak heat reject rate of less than 12 milliwatts. The detector heat load at 0.1 K is comparatively small at 1-2 microwatts. This paper will describe the 3-stage and 2-stage continuous ADRs that will be used to meet the cooling power and temperature stability requirements of the PIXIE detectors and telescope.
Li, Dafa
2016-05-01
The adiabatic theorem was proposed about 90 years ago and has played an important role in quantum physics. The quantitative adiabatic condition constructed from eigenstates and eigenvalues of a Hamiltonian is a traditional tool to estimate adiabaticity and has proven to be the necessary and sufficient condition for adiabaticity. However, recently the condition has become a controversial subject. In this paper, we list some expressions to estimate the validity of the adiabatic approximation. We show that the quantitative adiabatic condition is invalid for the adiabatic approximation via the Euclidean distance between the adiabatic state and the evolution state. Furthermore, we deduce general necessary and sufficient conditions for the validity of the adiabatic approximation by different definitions.
Dark Energy and Dark Matter from an additional adiabatic fluid
Dunsby, Peter K S; Reverberi, Lorenzo
2016-01-01
The Dark Sector is described by an additional barotropic fluid which evolves adiabatically during the universe's history and whose adiabatic exponent $\\gamma$ is derived from the standard definitions of specific heats. Although in general $\\gamma$ is a function of the redshift, the Hubble parameter and its derivatives, we find that our assumptions lead necessarily to solutions with $\\gamma = $ constant in a FLRW universe. The adiabatic fluid acts effectively as the sum of two distinct components, one evolving like non-relativistic matter and the other depending on the value of the adiabatic index. This makes the model particularly interesting as a way of simultaneously explaining the nature of both Dark Energy and Dark Matter, at least at the level of the background cosmology. The $\\Lambda$CDM model is included in this family of theories when $\\gamma = 0$. We fit our model to SNIa, $H(z)$ and BAO data, discussing the model selection criteria. The implications for the early-universe and the growth of small per...
International Nuclear Information System (INIS)
Highlights: → Solution densities and sound speeds were measured for aqueous solutions of thymidine. → Partial molar volumetric properties at infinite dilution and T = 298.15 K were derived. → The partial molar isentropic and isothermal compressions are of opposite signs. → The partial molar heat capacity for thymidine at infinite dilution was determined. - Abstract: Solution densities have been determined for aqueous solutions of thymidine at T = (288.15, 298.15, 303.15, and 313.15) K. The partial molar volumes at infinite dilution, V20, obtained from the density data were used to derive the partial molar isobaric expansion at infinite dilution for thymidine at T = 298.15 K, E20{E20=(∂V20/∂T)p}. The partial molar heat capacity at infinite dilution for thymidine, Cp,20, at T = 298.15 K has also been determined. Sound speeds have been measured for aqueous solutions of thymidine at T = 298.15 K. The partial molar isentropic compression at infinite dilution, KS,20, and the partial molar isothermal compression at infinite dilution, KT,20{KT,20=-(∂V20/∂P)T}, have been derived from the sound speed data. The V20, E20, Cp,20, and KS,20 results for thymidine are critically compared with those available from the literature.
Parameters of a possible FRC adiabatic compression experiment
International Nuclear Information System (INIS)
An experiment is described that would address the following research goals for field-reversed configurations (FRC). (a) Test FRC stability with a number of ion gyroradii relative to the plasma radius substantially greater than in present experiments. (b) Increase the electron temperature sufficiently to test the physics of electron energy confinement and of trapped-flux losses. (c) Improve confinement while remaining in a density regime (n less than or equal to 5 x 1015 cm-3) most likely to be relevant to fusion power production
Energy Technology Data Exchange (ETDEWEB)
Torrella, Enrique [Department of Applied Thermodynamics, Camino de Vera, 14, Polytechnic University of Valencia, E-46022 Valencia (Spain); Navarro-Esbri, Joaquin; Cabello, Ramon [Department of Technology, Campus de Riu Sec,University Jaume I, E-12071 Castellon (Spain)
2006-03-01
The present paper presents experimental results obtained from a refrigerating vapour-compression plant's shell-and-tube (1-2) evaporator working with R407C. Several tests have been carried out to study the influence of the evaporating pressure and the refrigerant's mass flow rate on the refrigerant's boiling heat-transfer coefficient inside horizontal tubes. This work has been performed by analyzing the variations of the evaporator's overall thermal-resistance, computed using the effectiveness-NTU method, considering the influence of pressure drops and glide at the evaporator, and finally transferring the results and conclusions to the boiling heat-transfer coefficient. It has been observed that the variations of the boiling heat-transfer coefficient show a dependence on the evaporating temperature and the refrigerant's mass-flow rate, which has been analyzed in the test range. [Author].
International Nuclear Information System (INIS)
Highlights: • A combined heat and power system based on CAES and HAT is proposed. • The design and modeling of the CAES–HAT based CHP system are laid out. • The performance assessment of the proposed system is carried out. • The system optimization is conducted to decide the maximum conditions. - Abstract: Renewable energy based power sources have grown rapidly in the past few years owing to the dual constraint of climate change and pollution control. Compressed air energy storage (CAES), as a large-scale energy storage system (ESS) technology, has huge potential to manage the intermittent renewable energy based power sources effectively. However, the compression heat generated during charge and waste heat carried in turbine exhaust during discharge are not fully recuperated in current stage. A combined heat and power (CHP) system consisting of a CAES system and a humid air turbine (HAT) system is proposed to utilize the both types of heat energy. The proposed system can boost the power output, enhance performance and improve efficiency through a simultaneous supply of power and heat. The thermodynamic analysis shows that the expansion train power can be improved about 26% compared with the conventional CAES system. The parametric analysis reveals that the exergy efficiency increases with the turbine inlet temperature (TIT) of high pressure turbine (HPT) and inlet pressure of low pressure turbine (LPT), but decreases with the TIT of LPT, L/G ratio and dry air inlet temperature of saturator. Meanwhile, the system optimization is carried out via particle swarm optimization (PSO) to determine the maximum power and exergy efficiency conditions
Adiabatic Rearrangement of Hollow PV Towers
Directory of Open Access Journals (Sweden)
Eric A Hendricks
2010-10-01
Full Text Available Diabatic heating from deep moist convection in the hurricane eyewall produces a towering annular structure of elevated potential vorticity (PV. This structure has been referred to as a hollow PV tower. The sign reversal of the radial gradient of PV satisfies the Charney-Stern necessary condition for combined barotropic-baroclinic instability. For thin enough annular structures, small perturbations grow exponentially, extract energy from the mean flow, and lead to hollow tower breakdown, with significant vortex structural and intensity change. The three-dimensional adiabatic rearrangements of two prototypical hurricane-like hollow PV towers (one thick and one thin are examined in an idealized framework. For both hollow towers, dynamic instability causes air parcels with high PV to be mixed into the eye preferentially at lower levels, where unstable PV wave growth rates are the largest. Little or no mixing is found to occur at upper levels. The mixing at lower and middle levels is most rapid for the breakdown of the thin hollow tower, consistent with previous barotropic results. For both hollow towers, this advective rearrangement of PV affects the tropical cyclone structure and intensity in a number of ways. First, the minimum central pressure and maximum azimuthal mean velocity simultaneously decrease, consistent with previous barotropic results. Secondly, isosurfaces of absolute angular momentum preferentially shift inward at low levels, implying an adiabatic mechanism by which hurricane eyewall tilt can form. Thirdly, a PV bridge, similar to that previously found in full-physics hurricane simulations, develops as a result of mixing at the isentropic levels where unstable PV waves grow most rapidly. Finally, the balanced mass field resulting from the PV rearrangement is warmer in the eye between 900 and 700 hPa. The location of this warming is consistent with observed warm anomalies in the eye, indicating that in certain instances the hurricane
Vapor Flow Patterns During a Start-Up Transient in Heat Pipes
Issacci, F.; Ghoniem, N, M.; Catton, I.
1996-01-01
The vapor flow patterns in heat pipes are examined during the start-up transient phase. The vapor core is modelled as a channel flow using a two dimensional compressible flow model. A nonlinear filtering technique is used as a post process to eliminate the non-physical oscillations of the flow variables. For high-input heat flux, multiple shock reflections are observed in the evaporation region. The reflections cause a reverse flow in the evaporation and circulations in the adiabatic region. Furthermore, each shock reflection causes a significant increase in the local pressure and a large pressure drop along the heat pipe.
Energy Technology Data Exchange (ETDEWEB)
Brueckmann, P. [Brueckmann Elektronik, Davos Dorf (Switzerland); Cyphelly, I. [Cyphelly and Cie, Les Brenets (Switzerland); Lindegger, M. [Circle Motor AG, Guemligen (Switzerland)
2006-11-15
This illustrated final report for the Swiss Federal Office of Energy (SFOE) deals with project concerning a compressed-air energy storage system. The authors state that the BOP-B is a highly efficient compressor or air motor and can work efficiently if the compression or expansion of the air takes place in a mostly isothermal way. First tests made on the heat-exchanger unit are reported on and conclusions are drawn. A second part of the paper deals with the motor-generator unit (Motgen). The mechanical and electrical construction of the Motgen is described along with the results of tests performed on the unit. The results of measurements made are presented and discussed.
International Nuclear Information System (INIS)
Liquid desiccant systems have been proposed as energy saving alternatives to the conventional vapor compression systems for handling the latent load. This paper presents the results from a study of the performance of a counter flow liquid desiccant dehumidifier. A heat and mass transfer theoretical model of an adiabatic packed column has been developed, based on the Runge-Kutta fixed step method, to predict the performance of the device under various operating conditions. Good agreement was found between experimental tests and the theoretical model, with the maximum deviation being ±2.9% in air outlet temperature, ±15.9% in air outlet humidity ratio and ±2.8% in solution outlet temperature. Following the model validation, the rate and the efficiency of the dehumidification process were assessed under the effects of variables, such as air temperature and humidity, desiccant temperature and humidity and air and desiccant flow rates. The three most commonly used liquid desiccant solutions, namely LiCl, LiBr and CaCl2 were evaluated against each other. The results show that high absorber efficiency and system efficiency could be achieved under humid conditions, low air mass flow rates and LiCl as the desiccant solution. - Highlights: ► Development of a theoretical model for an adiabatic structured dehumidifier. ► Theoretical model results are in excellent agreement with experimental data. ► LiCl has the best dehumidifier efficiency, in comparison to LiBr and CaCl2. ► LiCl has the highest dehumidification mass rate, in comparison to LiBr and CaCl2.
International Nuclear Information System (INIS)
The performance of a solar chemical heat pipe was studied using CO2 reforming of methane as a vehicle for storage and transport of solar energy. The endothermic reforming reaction was carried out in an Inconel reactor, packed with a Rh catalyst. The reactor was suspended in an insulated box receiver which was placed in the focal plane of the Schaeffer Solar Furnace of the Weizman Institute of Science. The exothermic methanation reaction was run in a 6-stage adiabatic reactor filled with the same Rh catalyst. Conversions of over 80% were achieved for both reactions. In the closed loop mode the products from the reformer and from the metanator were compressed into separate storage tanks. The two reactions were run either separately or 'on-line'. The complete process was repeated for over 60 cycles. The overall performance of the closed loop was quite satisfactory and scale-up work is in progress in the Solar Tower. (authors). 35 refs., 2 figs
Simulation of an Air-Source Heat Pump with Two-Stage Compression and Economizing for Cold Climates
Caskey, Stephen L.; Kultgen, Derek; Eckhard A. Groll; Hutzel, William; Menzi, Tobias
2012-01-01
A new air-source heat pump technology optimized for cold climates was designed and fabricated by the authors in close cooperation with three industrial partners. The constructed unit will undergo a field demonstration in a military barrack to identify heat pumps as cost effective systems that have less primary energy consumption when compared to traditional cold climate heating methods. A simulation model developed in EES predicted the designed heat pump performance at different ambient condi...
On the topology of adiabatic passage
Yatsenko, L P; Jauslin, H R
2002-01-01
We examine the topology of eigenenergy surfaces characterizing the population transfer processes based on adiabatic passage. We show that this topology is the essential feature for the analysis of the population transfers and the prediction of its final result. We reinterpret diverse known processes, such as stimulated Raman adiabatic passage (STIRAP), frequency-chirped adiabatic passage and Stark-chirped rapid adiabatic passage (SCRAP). Moreover, using this picture, we display new related possibilities of transfer. In particular, we show that we can selectively control the level which will be populated in STIRAP process in Lambda or V systems by the choice of the peak amplitudes or the pulse sequence.
Simulation of the Operating Performance for Supplementing-compressing Heat-pump%补气增焓热泵机组运行性能模拟研究
Institute of Scientific and Technical Information of China (English)
李艳; 王强
2011-01-01
Based on the operating characteristics of air-source-heat-pump in low temperatures, a single-stage air source heat pump and a supplementing-compressing air source heat pump was simulated and calculated. A calculation of heat pump with a process of refilling was presented and the most appropriate pressures in different evaporation temperatures were obtained, which would do a lot of help to improving the operating performance of air-source-heat-pump in low temperatures.%基于空气源热泵机组在低温工况下的运行特性，对单级空气源热泵机组及补气增焓热泵机组进行仿真模拟计算，提出一种带补气的热泵机组运行性能的计算方法，得出不同蒸发温度下最佳补气压力值，对改善低温环境下空气源热泵机组的运行性能具有重要意义。
Steam bottoming cycle for an adiabatic diesel engine
Poulin, E.; Demier, R.; Krepchin, I.; Walker, D.
1984-01-01
Steam bottoming cycles using adiabatic diesel engine exhaust heat which projected substantial performance and economic benefits for long haul trucks were studied. Steam cycle and system component variables, system cost, size and performance were analyzed. An 811 K/6.90 MPa state of the art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. The costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with aftercooling with the same total output were compared, the annual fuel savings less the added maintenance cost was determined to cover the increase initial cost of the TC/B system in a payback period of 2.3 years. Steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability are considered and the cost and performance of advanced systes are evaluated.
Li, Zi; Wang, Cong; Kang, Wei; Li, Chuanying; Zhang, Ping
2015-11-01
Ultrafast laser experiments on metals usually induce a high electron temperature and a low ion temperature and, thus, an energy relaxation process. The electron heat capacity and electron-phonon coupling factor are crucial thermal quantities to describe this process. We perform ab initio theoretical studies to determine these thermal quantities and their dependence on density and electron temperature for the metals aluminum and beryllium. The heat capacity shows an approximately linear dependence on the temperature, similar to free electron gas, and the compression only slightly affects the capacity. The electron-phonon coupling factor increases with both temperature and density, and the change observed for beryllium is more obvious than that for aluminum. The connections between thermal quantities and electronic/atomic structures are discussed in detail, and the different behaviors of aluminum and beryllium are well explained.
Caskey, Stephen Lance
2013-01-01
A Department of Defense project was established to conduct a field demonstration led by Purdue University with several industry partners. The technology investigated was an air-source, two-stage heat pump with closed-loop economizing. The field demonstration site was a military barracks on a National Guard base, Camp Atterbury, in southern Indiana. Two heat pumps were built at the Ray W. Herrick Laboratories and installed into two almost identical, barracks buildings. Data on the heat pump op...
Shortcut to adiabatic gate teleportation
Santos, Alan C.; Silva, Raphael D.; Sarandy, Marcelo S.
2016-01-01
We introduce a shortcut to the adiabatic gate teleportation model of quantum computation. More specifically, we determine fast local counterdiabatic Hamiltonians able to implement teleportation as a universal computational primitive. In this scenario, we provide the counterdiabatic driving for arbitrary n -qubit gates, which allows to achieve universality through a variety of gate sets. Remarkably, our approach maps the superadiabatic Hamiltonian HSA for an arbitrary n -qubit gate teleportation into the implementation of a rotated superadiabatic dynamics of an n -qubit state teleportation. This result is rather general, with the speed of the evolution only dictated by the quantum speed limit. In particular, we analyze the energetic cost for different Hamiltonian interpolations in the context of the energy-time complementarity.
Adiabatic quantum optimization with qudits
Amin, M H S; Smith, Peter
2011-01-01
Most realistic solid state devices considered as qubits are not true two-state systems but multi-level systems. They can approximately be considered as qubits only if the energy separation of the upper energy levels from the lowest two is very large. If this condition is not met, the upper states may affect the evolution and therefore cannot be neglected. Here, we consider devices with double-well potential as basic logical elements, and study the effect of higher energy levels, beyond the lowest two, on adiabatic quantum optimization. We show that the extra levels can be modeled by adding additional (ancilla) qubits coupled to the original (logical) qubits. The presence of these levels is shown to have no effect on the final ground state. We also study their influence on the minimum gap for a set of 8-qubit spin glass instances.
On a Nonlinear Model in Adiabatic Evolutions
Sun, Jie; Lu, Song-Feng
2016-08-01
In this paper, we study a kind of nonlinear model of adiabatic evolution in quantum search problem. As will be seen here, for this problem, there always exists a possibility that this nonlinear model can successfully solve the problem, while the linear model can not. Also in the same setting, when the overlap between the initial state and the final stare is sufficiently large, a simple linear adiabatic evolution can achieve O(1) time efficiency, but infinite time complexity for the nonlinear model of adiabatic evolution is needed. This tells us, it is not always a wise choice to use nonlinear interpolations in adiabatic algorithms. Sometimes, simple linear adiabatic evolutions may be sufficient for using. Supported by the National Natural Science Foundation of China under Grant Nos. 61402188 and 61173050. The first author also gratefully acknowledges the support from the China Postdoctoral Science Foundation under Grant No. 2014M552041
International Nuclear Information System (INIS)
The evolution of the microstructure of an AlMg4.7Si8 alloy is investigated by scanning electron microscopy and ex situ synchrotron tomography in as-cast condition and subsequent solution treatments for 1 h and 25 h at 540 °C, respectively. The eutectic Mg2Si phase, which presents a highly interconnected structure in the as-cast condition, undergoes significant morphological changes during the solution heat treatment. Statistical analyses of the particle distribution, the sphericity, the mean curvatures and Gaussian curvatures describe the disintegration of the interconnected seaweed-like structure followed by the rounding of the disintegrated fractions of the eutectic branches quantitatively. The ternary eutectic Si resulting from the Si-surplus to the stoichiometric Mg2Si ratio of the alloy undergoes similar changes. The morphological evolution during solution heat treatment is correlated with results of elevated temperature compression tests at 300 °C. The elevated temperature compressive strength is more sensitive to the degree of interconnectivity of the three dimensional Mg2Si network than to the shape of the individual particles
Energy Technology Data Exchange (ETDEWEB)
Hedwig, Gavin R., E-mail: G.Hedwig@massey.ac.nz [Institute of Fundamental Sciences-Chemistry, Massey University, Private Bag 11222, Palmerston North (New Zealand); Jameson, Geoffrey B. [Institute of Fundamental Sciences-Chemistry, Massey University, Private Bag 11222, Palmerston North (New Zealand); Hoiland, Harald [Department of Chemistry, University of Bergen, N-5020 Bergen (Norway)
2011-12-15
Highlights: > Solution densities and sound speeds were measured for aqueous solutions of thymidine. > Partial molar volumetric properties at infinite dilution and T = 298.15 K were derived. > The partial molar isentropic and isothermal compressions are of opposite signs. > The partial molar heat capacity for thymidine at infinite dilution was determined. - Abstract: Solution densities have been determined for aqueous solutions of thymidine at T = (288.15, 298.15, 303.15, and 313.15) K. The partial molar volumes at infinite dilution, V{sub 2}{sup 0}, obtained from the density data were used to derive the partial molar isobaric expansion at infinite dilution for thymidine at T = 298.15 K, E{sub 2}{sup 0}{l_brace}E{sub 2}{sup 0}=({partial_derivative}V{sub 2}{sup 0}/{partial_derivative}T){sub p}{r_brace}. The partial molar heat capacity at infinite dilution for thymidine, C{sub p,2}{sup 0}, at T = 298.15 K has also been determined. Sound speeds have been measured for aqueous solutions of thymidine at T = 298.15 K. The partial molar isentropic compression at infinite dilution, K{sub S,2}{sup 0}, and the partial molar isothermal compression at infinite dilution, K{sub T,2}{sup 0}{l_brace}K{sub T,2}{sup 0}=-({partial_derivative}V{sub 2}{sup 0}/{partial_derivative}P){sub T}{r_brace}, have been derived from the sound speed data. The V{sub 2}{sup 0}, E{sub 2}{sup 0}, C{sub p,2}{sup 0}, and K{sub S,2}{sup 0} results for thymidine are critically compared with those available from the literature.
DEFF Research Database (Denmark)
Ivarsson, Anders
to measure the soot content in terms of soot volume fraction. The measurement was based on absorption of light with wavelength between 500 and 520 nm. The third main topic of the project was to develop a CFD model of a pre-mixed flat flame. The commercial CFD software CFX 11.0 was used. Three cases...... emissions from the compression ignition engines (CI engines or diesel engines) are continuously increased. To comply with this, better modeling tools for the diesel combustion process are desired from the engine developers. The complex combustion process of a compression ignition engine may be divided......-mixed flat flame burner at atmospheric pressure. The fundamental mechanisms of this laboratory flame are identical with those of an IC engine. The high control of the laboratory flame and the easy access to it makes it valuable for model validation. Modeling of the pre-mixed flat flame was performed...
3D MHD Simulations of Spheromak Compression
Stuber, James E.; Woodruff, Simon; O'Bryan, John; Romero-Talamas, Carlos A.; Darpa Spheromak Team
2015-11-01
The adiabatic compression of compact tori could lead to a compact and hence low cost fusion energy system. The critical scientific issues in spheromak compression relate both to confinement properties and to the stability of the configuration undergoing compression. We present results from the NIMROD code modified with the addition of magnetic field coils that allow us to examine the role of rotation on the stability and confinement of the spheromak (extending prior work for the FRC). We present results from a scan in initial rotation, from 0 to 100km/s. We show that strong rotational shear (10km/s over 1cm) occurs. We compare the simulation results with analytic scaling relations for adiabatic compression. Work performed under DARPA grant N66001-14-1-4044.
Partial evolution based local adiabatic quantum search
Institute of Scientific and Technical Information of China (English)
Sun Jie; Lu Song-Feng; Liu Fang; Yang Li-Ping
2012-01-01
Recently,Zhang and Lu provided a quantum search algorithm based on partial adiabatic evolution,which beats the time bound of local adiabatic search when the number of marked items in the unsorted database is larger than one.Later,they found that the above two adiabatic search algorithms had the same time complexity when there is only one marked item in the database.In the present paper,following the idea of Roland and Cerf [Roland J and Cerf N J 2002Phys.Rev.A 65 042308],if within the small symmetric evolution interval defined by Zhang et al.,a local adiabatic evolution is performed instead of the original “global” one,this “new” algorithm exhibits slightly better performance,although they are progressively equivalent with M increasing.In addition,the proof of the optimality for this partial evolution based local adiabatic search when M =1 is also presented.Two other special cases of the adiabatic algorithm obtained by appropriately tuning the evolution interval of partial adiabatic evolution based quantum search,which are found to have the same phenomenon above,are also discussed.
Steam bottoming cycle for an adiabatic diesel engine
Energy Technology Data Exchange (ETDEWEB)
Poulin, E.; Demler, R.; Krepchin, I.; Walker, D.
1984-03-01
A study of steam bottoming cycles using adiabatic diesel engine exhaust heat projected substantial performance and economic benefits for long haul trucks. A parametric analysis of steam cycle and system component variables, system cost, size and performance was conducted. An 811 K/6.90 MPa state-of-the-art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. When applied to a NASA specified turbo-charged adiabatic diesel the bottoming system increased the diesel output by almost 18%. In a comparison of the costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with after-cooling with the same total output, the annual fuel savings less the added maintenance cost was determined to cover the increased initial cost of the TC/B system in a payback period of 2.3 years. Also during this program steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability were considered and the cost and performance of advanced systems were evaluated.
Digital Waveguide Adiabatic Passage Part 2: Experiment
Ng, Vincent; Chaboyer, Zachary J; Nguyen, Thach; Dawes, Judith M; Withford, Michael J; Greentree, Andrew D; Steel, M J
2016-01-01
Using a femtosecond laser writing technique, we fabricate and characterise three-waveguide digital adiabatic passage devices, with the central waveguide digitised into five discrete waveguidelets. Strongly asymmetric behaviour was observed, devices operated with high fidelity in the counter-intuitive scheme while strongly suppressing transmission in the intuitive. The low differential loss of the digital adiabatic passage designs potentially offers additional functionality for adiabatic passage based devices. These devices operate with a high contrast ($>\\!90\\%$) over a 60~nm bandwidth, centered at $\\sim 823$~nm.
Karthikayan, S; Sankaranarayanan, G; Karthikeyan, R
2015-11-01
Present energy strategies focus on environmental issues, especially environmental pollution prevention and control by eco-friendly green technologies. This includes, increase in the energy supplies, encouraging cleaner and more efficient energy management, addressing air pollution, greenhouse effect, global warming, and climate change. Biofuels provide the panorama of new fiscal opportunities for people in rural area for meeting their need and also the demand of the local market. Biofuels concern protection of the environment and job creation. Renewable energy sources are self-reliance resources, have the potential in energy management with less emissions of air pollutants. Biofuels are expected to reduce dependability on imported crude oil with connected economic susceptibility, reduce greenhouse gases, other pollutants and invigorate the economy by increasing demand and prices for agricultural products. The use of neat paradise tree oil and induction of eco-friendly material Hydrogen through inlet manifold in a constant pressure heat addition cycle engine (diesel engine) with optimized engine operating parameters such as injection timing, injection pressure and compression ratio. The results shows the heat utilization efficiency for neat vegetable oil is 29% and neat oil with 15% Hydrogen as 33%. The exhaust gas temperature (EGT) for 15% of H2 share as 450°C at full load and the heat release of 80J/deg. crank angle for 15% Hydrogen energy share. PMID:26025643
Double adiabatic theory of collisionless geodesic acoustic modes in tokamaks
Hassam, A B
2011-01-01
Collisionless geodesic acoustic modes in tokamaks being supersonic for large "safety factor" q, the CGL (G. Chew, M. Goldberger, F. Low, 1956)1 double-adiabatic fluid closure is applied to formulate a theory for these modes. The basic linear normal mode is obtained. External means to drive these modes at resonance, as has been proposed earlier, are explored. The external drivers considered include external magnetic forces to effect flux surface displacements, as well as non-axisymmetric ion heating. Finally, the damping of these modes from collisional magnetic pumping is investigated using a model set of CGL collision-corrected equations.
Monte Carlo Simulation of Adiabatic Cooling and Nuclear Magnetism
DEFF Research Database (Denmark)
Lindgård, Per-Anker; Viertiö, H. E.; Mouritsen, Ole G.
1988-01-01
in experimental studies of nuclear magnetism using adiabatic demagnetization methods. It is found that, although fluctuations reduce the transition temperatures by 40%, the isentropes are reduced by less than 10% relative to those calculated by mean-field theory. The dynamics of the ordering process following...... constant-temperature or constant-magnetic-field quenches into the antiferromagnetic phase is found at late times to obey the classical Allen-Cahn growth law. The qualitative features of isentropic quenches and the nonequilibrium ordering phenomena during controlled heating treatments at constant rate...
Institute of Scientific and Technical Information of China (English)
CAO Wenhua; LIU Songhao
2004-01-01
A novel scheme to compress optical pulses is proposed and demonstrated numerically, which is based on a nonlinear optical loop mirror constructed from dispersion decreasing fiber (DDF). We show that, in contrast to the conventional soliton-effect pulse compression in which compressed pulses are always accompanied by pedestals and frequency chirps owning to nonlinear effects, the proposed scheme can completely suppress pulse pedestals and frequency chirps. Unlike the adiabatic compression technique in which DDF length must increase exponentially with input pulsewidth, the proposed scheme does not require adiabatic condition and therefore can be used to compress long pulses by using reasonable fiber lengths. For input pulses with peak powers higher than a threshold value, the compressed pulses can propagate like fundamental solitons. Furthermore, the scheme is fairly insensitive to small variations in the loop length and is more robust to higher-order nonlinear effects and initial frequency chirps than the adiabatic compression technique.
Adiabatic hydrodynamics: The eightfold way to dissipation
Haehl, Felix M; Rangamani, Mukund
2015-01-01
We provide a complete solution to hydrodynamic transport at all orders in the gradient expansion compatible with the second law constraint. The key new ingredient we introduce is the notion of adiabaticity, which allows us to take hydrodynamics off-shell. Adiabatic fluids are such that off-shell dynamics of the fluid compensates for entropy production. The space of adiabatic fluids is quite rich, and admits a decomposition into seven distinct classes. Together with the dissipative class this establishes the eightfold way of hydrodynamic transport. Furthermore, recent results guarantee that dissipative terms beyond leading order in the gradient expansion are agnostic of the second law. While this completes a transport taxonomy, we go on to argue for a new symmetry principle, an Abelian gauge invariance that guarantees adiabaticity in hydrodynamics. We suggest that this symmetry is the macroscopic manifestation of the microscopic KMS invariance. We demonstrate its utility by explicitly constructing effective ac...
Adiabatic Invariance of Oscillons/I-balls
Kawasaki, Masahiro; Takeda, Naoyuki
2015-01-01
Real scalar fields are known to fragment into spatially localized and long-lived solitons called oscillons or $I$-balls. We prove the adiabatic invariance of the oscillons/$I$-balls for a potential that allows periodic motion even in the presence of non-negligible spatial gradient energy. We show that such potential is uniquely determined to be the quadratic one with a logarithmic correction, for which the oscillons/$I$-balls are absolutely stable. For slightly different forms of the scalar potential dominated by the quadratic one, the oscillons/$I$-balls are only quasi-stable, because the adiabatic charge is only approximately conserved. We check the conservation of the adiabatic charge of the $I$-balls in numerical simulation by slowly varying the coefficient of logarithmic corrections. This unambiguously shows that the longevity of oscillons/$I$-balls is due to the adiabatic invariance.
Adiabatic Quantum Search in Open Systems
Wild, Dominik S.; Gopalakrishnan, Sarang; Knap, Michael; Yao, Norman Y.; Lukin, Mikhail D.
2016-10-01
Adiabatic quantum algorithms represent a promising approach to universal quantum computation. In isolated systems, a key limitation to such algorithms is the presence of avoided level crossings, where gaps become extremely small. In open quantum systems, the fundamental robustness of adiabatic algorithms remains unresolved. Here, we study the dynamics near an avoided level crossing associated with the adiabatic quantum search algorithm, when the system is coupled to a generic environment. At zero temperature, we find that the algorithm remains scalable provided the noise spectral density of the environment decays sufficiently fast at low frequencies. By contrast, higher order scattering processes render the algorithm inefficient at any finite temperature regardless of the spectral density, implying that no quantum speedup can be achieved. Extensions and implications for other adiabatic quantum algorithms will be discussed.
Adiabatic calorimeter for measuring absorbed dose of IHEP synchrotron secondary radiation
International Nuclear Information System (INIS)
An adiabatic calorimeter for measuring the value of absorbed dose of mixed radiation generated by 70 GeV proton synchrotron is described. The calorimetric system consists of a working body (a core) and a shell (a screen). The calorimeter adiabaticity is provided by the absence of the core-shell heat exchange by maintaining the shell temperature equal to the core temperature and, consequently, the whole energy generated in the core goes for its heating. The work showed the possibility of carrying out the adiabatic calorimetric measurements of absorbed dose of secondary radiation generated by un accelerated proton beam under the conditions of alternating magnetic and electric fields at the IHEP proton synchrotron at the average dose rate not less than 5x10-3 Wxkg-1
Morduchow, Morris
1955-01-01
A survey of integral methods in laminar-boundary-layer analysis is first given. A simple and sufficiently accurate method for practical purposes of calculating the properties (including stability) of the laminar compressible boundary layer in an axial pressure gradient with heat transfer at the wall is presented. For flow over a flat plate, the method is applicable for an arbitrarily prescribed distribution of temperature along the surface and for any given constant Prandtl number close to unity. For flow in a pressure gradient, the method is based on a Prandtl number of unity and a uniform wall temperature. A simple and accurate method of determining the separation point in a compressible flow with an adverse pressure gradient over a surface at a given uniform wall temperature is developed. The analysis is based on an extension of the Karman-Pohlhausen method to the momentum and the thermal energy equations in conjunction with fourth- and especially higher degree velocity and stagnation-enthalpy profiles.
Dharma-wardana, M W C
2012-01-01
The pair-interactions U_{ij}(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., g_{ij}(r). Great simplicity is achieved if U_{ij}(r) could be directly used to predict material properties via classical simulations, avoiding many-body wavefunctions. Warm dense matter (WDM) is encountered in quasi-equilibria where the electron temperature $T_e$ differs from the ion temperature T_i, as in laser-heated or in shock-compressed matter. The electron PDFs g_{ee}(r) as perturbed by the ions are used to evaluate fully non-local exchange-correlation corrections to the free energy, using Hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with T_e \
Ye, Xia; Zhang, Jianwen
2016-08-01
This paper concerns the asymptotic behavior of the solution to an initial-boundary value problem of the cylindrically symmetric Navier–Stokes equations with large data for compressible heat-conducting ideal fluids, as the shear viscosity μ goes to zero. A suitable corrector function (the so-called boundary-layer type function) is constructed to eliminate the disparity of boundary values. As by-products, the convergence rates of the derivatives in L 2 are obtained and the boundary-layer thickness (BL-thickness) of the value O≤ft({μα}\\right) with α \\in ≤ft(0,1/2\\right) is shown by an alternative method, compared with the results proved in Jiang and Zhang (2009 SIAM J. Math. Anal. 41 237–68) and Qin et al (2015 Arch. Ration. Mech. Anal. 216 1049–86).
Hu, Kainan; Geng, Shaojuan
2016-01-01
A decoupled scheme based on the Hermite expansion to construct lattice Boltzmann models for the compressible Navier-Stokes equations with arbitrary specific heat ratio is proposed. The local equilibrium distribution function including the rotational velocity of particle is decoupled into two parts, i.e. the local equilibrium distribution function of the translational velocity of particle and that of the rotational velocity of particle. From these two local equilibrium functions, two lattice Boltzmann models are derived via the Hermite expansion, namely one is in relation to the translational velocity and the other is connected with the rotational velocity. Accordingly, the distribution function is also decoupled. After this, the evolution equation is decoupled into the evolution equation of the translational velocity and that of the rotational velocity. The two evolution equations evolve separately. The lattice Boltzmann models used in the scheme proposed by this work are constructed via the Hermite expansion...
Adiabatic Approximation, Semiclassical Scattering, and Unidirectional Invisibility
Mostafazadeh, Ali
2014-01-01
arXiv:1401.4315v3 [quant-ph] 27 Feb 2014 Adiabatic Approximation, Semiclassical Scattering, and Unidirectional Invisibility Ali Mostafazadeh∗ Department of Mathematics, Ko¸c University, 34450 Sarıyer, Istanbul, Turkey Abstract The transfer matrix of a possibly complex and energy-dependent scattering potential can be identified with the S-matrix of a two-level time-dependent non-Hermitian Hamiltonian H( ). We show that the application of the adiabatic approximation ...
Adiabatic description of nonspherical quantum dot models
Energy Technology Data Exchange (ETDEWEB)
Gusev, A. A., E-mail: gooseff@jinr.ru; Chuluunbaatar, O.; Vinitsky, S. I. [Joint Institute for Nuclear Research (Russian Federation); Dvoyan, K. G.; Kazaryan, E. M.; Sarkisyan, H. A. [Russian-Armenian (Slavonic) University (Armenia); Derbov, V. L.; Klombotskaya, A. S.; Serov, V. V. [Saratov State University (Russian Federation)
2012-10-15
Within the effective mass approximation an adiabatic description of spheroidal and dumbbell quantum dot models in the regime of strong dimensional quantization is presented using the expansion of the wave function in appropriate sets of single-parameter basis functions. The comparison is given and the peculiarities are considered for spectral and optical characteristics of the models with axially symmetric confining potentials depending on their geometric size, making use of the complete sets of exact and adiabatic quantum numbers in appropriate analytic approximations.
Adiabatic Connection for Strictly-Correlated Electrons
Liu, Zhenfei; Burke, Kieron
2009-01-01
Modern density functional theory (DFT) calculations employ the Kohn-Sham (KS) system of non-interacting electrons as a reference, with all complications buried in the exchange-correlation energy (Exc). The adiabatic connection formula gives an exact expression for Exc. We consider DFT calculations that instead employ a reference of strictly-correlated electrons. We define a "decorrelation energy" that relates this reference to the real system, and derive the corresponding adiabatic connection...
On adiabatic invariant in generalized Galileon theories
Ema, Yohei; Jinno, Ryusuke; Mukaida, Kyohei; Nakayama,Kazunori
2015-01-01
We consider background dynamics of generalized Galileon theories in the context of inflation, where gravity and inflaton are non-minimally coupled to each other. In the inflaton oscillation regime, the Hubble parameter and energy density oscillate violently in many cases, in contrast to the Einstein gravity with minimally coupled inflaton. However, we find that there is an adiabatic invariant in the inflaton oscillation regime in any generalized Galileon theory. This adiabatic invariant is us...
International Nuclear Information System (INIS)
Fluid selection for thermodynamic cycles like refrigeration cycles, heat pumps or organic Rankine cycles remains an actual topic. Generally the search for a working fluid is based on experimental approaches or on a not very systematic trial and error approach, far from being elegant. An alternative method may be a theory based reverse engineering approach, proposed and investigated here: The design process should start with an optimal process and with (abstract) properties of the fluid needed to fit into this optimal process, best described by some general equation of state and the corresponding fluid-describing parameters. These should be analyzed and optimized with respect to the defined model process, which also has to be optimized simultaneously. From this information real fluids can be selected or even synthesized which have fluid defining properties in the optimum regime like critical temperature or ideal gas capacities of heat, allowing to find new working fluids, not considered so far. The number and kind of the fluid-defining parameters is mainly based on the choice of the used EOS (equation of state). The property model used in the present work is based on the cubic Peng–Robinson equation, chosen due to its moderate numerical expense, sufficient accuracy as well as a general availability of the fluid-defining parameters for many compounds. The considered model-process works between the temperature levels of 273.15 and 333.15 K and can be used as heat pump for supplying buildings with heat, typically. The objective functions are the COP (coefficient of performance) and the VHC (volumetric heating capacity) as a function of critical pressure, critical temperature, acentric factor and two coefficients for the temperature-dependent isobaric ideal gas heat capacity. Also, the steam quality at the compressor entrance has to be regarded as a problem variable. The results give clear hints regarding optimal fluid parameters of the analyzed process and deepen
Hierarchical theory of quantum adiabatic evolution
Zhang, Qi; Gong, Jiangbin; Wu, Biao
2014-12-01
Quantum adiabatic evolution is a dynamical evolution of a quantum system under slow external driving. According to the quantum adiabatic theorem, no transitions occur between nondegenerate instantaneous energy eigenstates in such a dynamical evolution. However, this is true only when the driving rate is infinitesimally small. For a small nonzero driving rate, there are generally small transition probabilities between the energy eigenstates. We develop a classical mechanics framework to address the small deviations from the quantum adiabatic theorem order by order. A hierarchy of Hamiltonians is constructed iteratively with the zeroth-order Hamiltonian being determined by the original system Hamiltonian. The kth-order deviations are governed by a kth-order Hamiltonian, which depends on the time derivatives of the adiabatic parameters up to the kth-order. Two simple examples, the Landau-Zener model and a spin-1/2 particle in a rotating magnetic field, are used to illustrate our hierarchical theory. Our analysis also exposes a deep, previously unknown connection between classical adiabatic theory and quantum adiabatic theory.
Adiabatic nanofocusing: spectroscopy, transport and imaging investigation of the nano world
Giugni, A.; Allione, M.; Torre, B.; Das, G.; Francardi, M.; Moretti, M.; Malerba, M.; Perozziello, G.; Candeloro, P.; Di Fabrizio, E.
2014-11-01
Adiabatic compression plays a fundamental role in the realization of localized enhanced electromagnetic field hot spots, it provides the possibility to focus at nanoscale optical excitation. It differs from the well-known lightning rod effect since it is based on the lossless propagation of surface plasmon polaritons (SPPs) up to a nano-sized metal tip where the energy density is largely enhanced. Here we discuss two important applications of adiabatic compression: Raman and hot electron spectroscopy at nanometric resolution. The underlying phenomena are the conversion of SPPs into photons or hot electrons. New scanning probe spectroscopy techniques along with experimental results are discussed. We foresee that these techniques will play a key role in relating the functional and structural properties of matter at the nanoscale.
Adiabatic nanofocusing: Spectroscopy, transport and imaging investigation of the nano world
Giugni, Andrea
2014-11-01
Adiabatic compression plays a fundamental role in the realization of localized enhanced electromagnetic field hot spots, it provides the possibility to focus at nanoscale optical excitation. It differs from the well-known lightning rod effect since it is based on the lossless propagation of surface plasmon polaritons (SPPs) up to a nano-sized metal tip where the energy density is largely enhanced. Here we discuss two important applications of adiabatic compression: Raman and hot electron spectroscopy at nanometric resolution. The underlying phenomena are the conversion of SPPs into photons or hot electrons. New scanning probe spectroscopy techniques along with experimental results are discussed. We foresee that these techniques will play a key role in relating the functional and structural properties of matter at the nanoscale.
Choi, Won-Chang; Khil, Bae-Soo; Chae, Young-Seok; Liang, Qi-Bo; Yun, Hyun-Do
2014-01-01
This paper presents experimental results that can be applied to select a possible phase change material (PCM), such as a latent heat material (LHM), to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests) were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH)2 · 8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete.
Choi, Won-Chang; Khil, Bae-Soo; Chae, Young-Seok; Liang, Qi-Bo; Yun, Hyun-Do
2014-01-01
This paper presents experimental results that can be applied to select a possible phase change material (PCM), such as a latent heat material (LHM), to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests) were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH)2 · 8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete. PMID:25133259
Directory of Open Access Journals (Sweden)
Won-Chang Choi
2014-01-01
Full Text Available This paper presents experimental results that can be applied to select a possible phase change material (PCM, such as a latent heat material (LHM, to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH2·8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete.
Dharma-wardana, M W C
2012-09-01
The pair interactions Uij(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., gij(r). Great simplicity is achieved if Uij(r) could be directly used to predict material properties via classical simulations, avoiding many-body wave functions. Warm dense matter (WDM) is encountered in quasiequilibria where the electron temperature Te differs from the ion temperature Ti, as in laser-heated or in shock-compressed matter. The electron PDFs gee(r) as perturbed by the ions are used to evaluate fully nonlocal exchange-correlation corrections to the free energy, using hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with Te≠Ti, and valid for times shorter than the electron-ion relaxation time. In some cases the potentials develop attractive regions and then become repulsive and "Yukawa-like" for higher Te. These results clarify the origin of initial phonon hardening and rapid release. Pair potentials for shock-heated WDM show that phonon hardening would not occur in most such systems. Defining meaningful quasiequilibrium static transport coefficients consistent with the dynamic values is addressed. There seems to be no meaningful "static conductivity" obtainable by extrapolating experimental or theoretical σ(ω,Ti,Te) to ω→0, unless Ti→Te as well. Illustrative calculations of quasistatic resistivities R(Ti,Te) of laser-heated as well as shock-heated aluminum and silicon are presented using our pseudopotentials, pair potentials, and classical integral equations. The quasistatic resistivities display clear differences in their temperature evolutions, but are not the strict ω→0 limits of the dynamic values.
Dharma-wardana, M. W. C.
2012-09-01
The pair interactions Uij(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., gij(r). Great simplicity is achieved if Uij(r) could be directly used to predict material properties via classical simulations, avoiding many-body wave functions. Warm dense matter (WDM) is encountered in quasiequilibria where the electron temperature Te differs from the ion temperature Ti, as in laser-heated or in shock-compressed matter. The electron PDFs gee(r) as perturbed by the ions are used to evaluate fully nonlocal exchange-correlation corrections to the free energy, using hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with Te≠Ti, and valid for times shorter than the electron-ion relaxation time. In some cases the potentials develop attractive regions and then become repulsive and “Yukawa-like” for higher Te. These results clarify the origin of initial phonon hardening and rapid release. Pair potentials for shock-heated WDM show that phonon hardening would not occur in most such systems. Defining meaningful quasiequilibrium static transport coefficients consistent with the dynamic values is addressed. There seems to be no meaningful “static conductivity” obtainable by extrapolating experimental or theoretical σ(ω,Ti,Te) to ω→0, unless Ti→Te as well. Illustrative calculations of quasistatic resistivities R(Ti,Te) of laser-heated as well as shock-heated aluminum and silicon are presented using our pseudopotentials, pair potentials, and classical integral equations. The quasistatic resistivities display clear differences in their temperature evolutions, but are not the strict ω→0 limits of the dynamic values.
Effects of compressibility in the mantle convection Equations
Trubitsyn, V. P.; Trubitsyna, A. P.
2015-11-01
The Boussinesq approximation of thermal convection equations results from neglecting the number of the terms which are actually not small in the conditions of the Earth's mantle. However, the error of calculating the structure of the convective flows is lower than the discarded terms. In this work we analyze the causes of this fact by successively passing from the general equations for a heated viscous compressible fluid to the simpler thermal convection equations by rejecting small quantities with the parameters of the presentday Earth. We consider the anelastic liquid approximation (ALA), truncated anelastic liquid approximation (TALA), extended Boussinesq approximation (EBA), and the simplest classical Boussinesq approximation (BA) which fully disregards the compressibility of a fluid. With the parameters of the mantle, BA is only accurate when describing the flow velocities, while the temperature is predicted with an error of up to a few dozen percent. Therefore, it appears reasonable to consider an intermediate approximation between EBA and BA, in which the effects of compressibility are only taken into account for temperature. This approximation can be referred to as the superadiabatic Boussinesq approximation (SBA) for temperature T sa. The corresponding equations are structurally similar to the standard Boussinesq approximation but with a superadiabatic temperature T sa instead of total temperature T. In this simple approximation, the calculated structure of the convective flows and the distribution of total temperature (obtained by adding the known adiabatic T a to the calculated T sa) are more accurate than in the classical Boussinesq approximation.
Hydrodynamics compression in inertial confinement fusion (ICF) plasma
International Nuclear Information System (INIS)
The hydrodynamics compression in ICF plasma has been theoretically studied using conservation equations. The study is based on single fluid plasma model. A comparison is made between shock and adiabatic compression. It seems that the amount of energy required to compress the fusion fuel by same factor is greater for strong shocks but is nearly same for weak shocks in comparison with the adiabatic compression. It can be inferred as conclusion that weak shocks are appropriate for compression in ICF. The ratio of pressure, density and temperature are obtained in terms of shock speed, i.e., in terms of mach numbers. The limitation of achievable density of fuel in shock is calculated beyond which there is expansion rather than compression. (author)
An Integrated Programming and Development Environment for Adiabatic Quantum Optimization
Humble, Travis S.; McCaskey, Alex J.; Bennink, Ryan S.; Billings, Jay J.; D'Azevedo, Ed F.; Sullivan, Blair D.; Klymko, Christine F.; Seddiqi, Hadayat
2013-01-01
Adiabatic quantum computing is a promising route to the computational power afforded by quantum information processing. The recent availability of adiabatic hardware has raised challenging questions about how to evaluate adiabatic quantum optimization programs. Processor behavior depends on multiple steps to synthesize an adiabatic quantum program, which are each highly tunable. We present an integrated programming and development environment for adiabatic quantum optimization called JADE tha...
Energy Technology Data Exchange (ETDEWEB)
De Alba Rosano, Mauricio [CIE, UNAM, Temixco, Morelos (Mexico)
2000-07-01
A new computational program has been developed in order to design single stage compression heat pumps. This software, named CICLO 1.0 allows the design of water-water, water-air, air-water and air-air heat pumps, for industrial and residential applications. CICLO 1.0 simulates three types of compressors: reciprocating, screw and scroll. Also has a data base created with REFPROP software which includes eleven refrigerants. The condenser and evaporator simulation includes global conductance (UA) determination, and when one or both are shell and tube's type, this software shows the even number of tube passes by shell. The software determines the best compressor and refrigerant setup taking the COP as a parameter; in order to obtain this, is necessary to know the inlet/outlet conditions of the fluid to be heated, the inlet conditions of the fluid that gives heat, and the electric motor efficiency that drives the compressor. The afforded results by CICLO 1.0 are: operation conditions from compression cycle, that means, pressures and temperatures at the inlet/outlet from every heat pump component are determined: as well as refrigerant mass flux, COP, power required by compressor, volumetric and isentropic efficiencies, heat exchangers global conductance and more data. CICLO 1.0 has been executed with heat pump data that nowadays are operating, and the results from the simulation have been very similar each other with data reported from operational facilities. [Spanish] Se ha desarrollado un nuevo programa computacional para el diseno de bombas de calor por compresion de vapor de una sola etapa. Este programa, CICLO 1.0, permite el diseno de bombas de calor de tipo: agua-agua, agua-aire, aire-agua y aire-aire, que se utilicen para aplicaciones industriales, de servicios y residenciales. CICLO 1.0 simula tres tipos de compresores: reciprocante, de tornillo y scroll: cuenta con una base de datos de refrigerantes creada con el programa REFPROP la cual incluye once
NOVEL CONCEPTS FOR THE COMPRESSION OF LARGE VOLUMES OF CARBON DIOXIDE-PHASE III
Energy Technology Data Exchange (ETDEWEB)
Moore, J. Jeffrey; Allison, Timothy; Evans, Neal; Moreland, Brian; Hernandez, Augusto; Day, Meera; Ridens, Brandon
2014-06-30
successfully demonstrated good performance and mechanical behavior. In Phase III, a pilot compression plant consisting of a multi-stage centrifugal compressor with cooled diaphragm technology has been designed, constructed, and tested. Comparative testing of adiabatic and cooled tests at equivalent inlet conditions shows that the cooled diaphragms reduce power consumption by 3-8% when the compressor is operated as a back-to-back unit and by up to 9% when operated as a straight-though compressor with no intercooler. The power savings, heat exchanger effectiveness, and temperature drops for the cooled diaphragm were all slightly higher than predicted values but showed the same trends.
Analytical equation for calculating the adiabatic temperature of the wet-bulb thermometer
Baskakov, A. P.; Rakov, O. A.
2013-03-01
A formula for calculating the adiabatic temperature of the wet-bulb thermometer has been obtained analytically without using the analogy between the heat and mass transfer processes. A comparison of the results of calculations with the use of this formula and formulas of other authors used in the technical literature has been made.
Rapid compressions in a captive bubble apparatus are isothermal
Yan, Wenfei; Hall, Stephen B.
2003-01-01
Captive bubbles are commonly used to determine how interfacial films of pulmonary surfactant respond to changes in surface area, achieved by varying hydrostatic pressure. Although assumed to be isothermal, the gas phase temperature (Tg) would increase by >100°C during compression from 1 to 3 atm if the process were adiabatic. To determine the actual change in temperature, we monitored pressure (P) and volume (V) during compressions lasting 10 min after the compression when the two phases shou...
Holland, Scott D.; Murphy, Kelly J.
1993-01-01
Since mission profiles for airbreathing hypersonic vehicles such as the National Aero-Space Plane include single-stage-to-orbit requirements, real gas effects may become important with respect to engine performance. The effects of the decrease in the ratio of specific heats have been investigated in generic three-dimensional sidewall compression scramjet inlets with leading-edge sweep angles of 30 and 70 degrees. The effects of a decrease in ratio of specific heats were seen by comparing data from two facilities in two test gases: in the Langley Mach 6 CF4 Tunnel in tetrafluoromethane (where gamma=1.22) and in the Langley 15-Inch Mach 6 Air Tunnel in perfect gas air (where gamma=1.4). In addition to the simulated real gas effects, the parametric effects of cowl position, contraction ratio, leading-edge sweep, and Reynolds number were investigated in the 15-Inch Mach 6 Air Tunnel. The models were instrumented with a total of 45 static pressure orifices distributed on the sidewalls and baseplate. Surface streamline patterns were examined via oil flow, and schlieren videos were made of the external flow field. The results of these tests have significant implications to ground based testing of inlets in facilities which do not operate at flight enthalpies.
Directory of Open Access Journals (Sweden)
Cristina OLARESCU
2013-06-01
Full Text Available The paper presents the results of anexperimental study performed with black pine (Pinusnigra L. and spruce (Picea abies L. wood, originatingfrom mature trees and thinnings cut from the sameparcel from the Stroesti-Arges region in Romania.After air drying and conditioning, the defect-freetest boards were cut into standard 20x20x60mmsamples for the compression test. The compressionstrength was measured and the rupture mode incompression was analyzed.Therefore, the sampleswere first dried to oven-dry state, then heat-treated athigh temperatures (180 and 200ºC for 1, 2, 3 and 4hours. Sets of 10 samples from each wood species,wood assortment and treating regime were tested.The obtained results were comparativelyanalyzed for the two species (pine vs. spruce and forthe two wood assortments (mature wood vs, thinwood. Then they were also expressed relatively tothe mass loss, considered to be the main indiactor ofthe degradation suffered by wood during the heattreatment.A graph was drawn for each species andassortment in order to establish the optimum treatingregime, considering the correlated influence of theheat treatment conditions upon all three analyzedproperties (mass loss, dimensional stability andcompression strength.The results of the present research are to bevalorized at the manufacturing of solid wood panelsmade from heat-treated lamellas.
Directory of Open Access Journals (Sweden)
Baofeng Yao
2014-11-01
Full Text Available A dual loop organic Rankine cycle (DORC system is designed to recover waste heat from a heavy-duty compressed natural gas engine (CNGE, and the performance of the DORC–CNGE combined system is simulated and discussed. The DORC system includes high-temperature (HT and low-temperature (LT cycles. The HT cycle recovers energy from the exhaust gas emitted by the engine, whereas the LT cycle recovers energy from intake air, engine coolant, and the HT cycle working fluid in the preheater. The mathematical model of the system is established based on the first and second laws of thermodynamics. The characteristics of waste heat energy from the CNGE are calculated according to engine test data under various operating conditions. Moreover, the performance of the DORC–CNGE combined system is simulated and analyzed using R245fa as the working fluid. Results show that the maximum net power output and the maximum thermal efficiency of the DORC system are 29.37 kW and 10.81%, respectively, under the rated power output condition of the engine. Compared with the original CNG engine, the maximum power output increase ratio and the maximum brake specific fuel consumption improvement ratio are 33.73% and 25%, respectively, in the DORC–CNGE combined system.
On criterion of modal adiabaticity
Institute of Scientific and Technical Information of China (English)
WANG; Ning(
2001-01-01
［1］Pierce, A. D., Extension of the method of normal modes to sound propagation in an almost-stratified medium, J. Acoust.Soc. Am., 1965, 37: 19－27.［2］Wang, D. Z. , Shang, E. C., Underwater Acoustics (in Chinese), Beijing: Science Press, 1981.［3］Zhang Renhe, Li Fenghua, Beam-displacement rya-mode theory of sound propagation in shallow water, Science in China, Ser.A, 1999, 42(7): 739－749.［4］Zhou Jixun, Zhang Xuezhen, Rogers P., Resonance interaction of sound waves with internal solitons in coastal zone, J.Acoust. Soc. Am., 1991, 90: 2042－2054.［5］Shang, E. C., Wang, Y. Y., The impact of mesoscale oceanic structure on global-scale acoustic propagation, in Theoretical and Computational Acoustics (ed. Ding Lee et al. ), Singapore: World Scientific Publishing Co. , 1996, 409－431.［6］Milder, D. M., Ray and wave invariants for SOFAR channel propagation, J. Acoust. Soc. Am., 1969, 46: 1259－1263.［7］Nag l, A., Milder, D. M., Adiabatic mode theory of underwater sound propagation in a range-dependent environment, J.Acoust. Soc. Am., 1978, 63: 739－749.［8］Brekhovskikh, L. M., Waves in Layered Media, 2nd ed., New York: Academic Press Inc., 1973.［9］Brekhovskikh, L. M., Lysanov, Yu., Fundamental of Ocean Acoustics, Ch. 7, Sec. 7.2, Berlin: Springer-Verlag, 1982.［10］Evans, R. B., A coupled mode solution for acoustic propagation in a wave-guide with stepwise depth variations of a penerable bottom, J. Acoust. Soc. A.m., 1983, 74: 188－195.［11］Jensen, F. B., Kuperman, W. A., Porter, M. B. et al., Computational Ocean Acoustics, New York: Springer-Verlag,1992.［12］Wang Ning, Inverse scattering problem for the coupled second order ODE, Journal of The Physical Society of Japan, 1995, 64(12): 4907－4915.
Evolution Of Nonlinear Waves in Compressing Plasma
Energy Technology Data Exchange (ETDEWEB)
P.F. Schmit, I.Y. Dodin, and N.J. Fisch
2011-05-27
Through particle-in-cell simulations, the evolution of nonlinear plasma waves is examined in one-dimensional collisionless plasma undergoing mechanical compression. Unlike linear waves, whose wavelength decreases proportionally to the system length L(t), nonlinear waves, such as solitary electron holes, conserve their characteristic size {Delta} during slow compression. This leads to a substantially stronger adiabatic amplification as well as rapid collisionless damping when L approaches {Delta}. On the other hand, cessation of compression halts the wave evolution, yielding a stable mode.
Adiabatic cooling of a single trapped ion
Poulsen, Gregers
2012-01-01
We present experimental results on adiabatic cooling of a single 40Ca+ ion in a linear radiofrequency trap. After a period of laser cooling, the secular frequency along the rf-field-free axis is adiabatically lowered by nearly a factor of eight from 583 kHz to 75 kHz. For an ion originally Doppler laser cooled to a temperature of 0.65 +/- 0.03 mK, a temperature of 87 +/- 7 \\mu K is measured after the adiabatic expansion. Applying the same adiabatic cooling procedure to a single sideband cooled ion in the ground state (P0 = 0.978 +/- 0.002) resulted in a final ground state occupation of 0.947 +/- 0.005. Both results are in excellent agreement with an essentially fully adiabatic behavior. The results have a wide range of perspectives within such diverse fields as ion based quantum information science, high resolution molecular ion spectroscopy and ion chemistry at ultra-low temperatures.
Impact of Turbocharger Non-Adiabatic Operation on Engine Volumetric Efficiency and Turbo Lag
Shaaban, S; Seume, J.
2012-01-01
Turbocharger performance significantly affects the thermodynamic properties of the working fluid at engine boundaries and hence engine performance. Heat transfer takes place under all circumstances during turbocharger operation. This heat transfer affects the power produced by the turbine, the power consumed by the compressor, and the engine volumetric efficiency. Therefore, non-adiabatic turbocharger performance can restrict the engine charging process and hence engine performance. The prese...
Adiabatic Quantum Computing for Random Satisfiability Problems
Hogg, T
2003-01-01
The discrete formulation of adiabatic quantum computing is compared with other search methods, classical and quantum, for random satisfiability (SAT) problems. With the number of steps growing only as the cube of the number of variables, the adiabatic method gives solution probabilities close to one for problem sizes feasible to evaluate. However, for these sizes the minimum energy gaps are fairly large, so may not reflect asymptotic behavior where costs are dominated by tiny gaps. Moreover, the resulting search costs are much higher than other methods, but can be reduced by using fewer steps. Variants of the quantum algorithm that do not match the adiabatic limit give lower costs, on average, and slower growth than the conventional GSAT heuristic method.
Energy efficiency of adiabatic superconductor logic
Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki
2015-01-01
Adiabatic superconductor logic (ASL), including adiabatic quantum-flux-parametron (AQFP) logic, exhibits high energy efficiency because its bit energy can be decreased below the thermal energy through adiabatic switching operations. In the present paper, we present the general scaling laws of ASL and compare the energy efficiency of ASL with those of other energy-efficient logics. Also, we discuss the minimum energy-delay product (EDP) of ASL at finite temperature. Our study shows that there is a maximum temperature at which the EDP can reach the quantum limit given by ħ/2, which is dependent on the superconductor material and the Josephson junction quality, and that it is reasonable to operate ASL at cryogenic temperatures in order to achieve an EDP that approaches ħ/2.
Directory of Open Access Journals (Sweden)
Byung Jae Lee
2014-12-01
Full Text Available In this study, adiabatic temperature rise tests depending on binder type and adiabatic specimen volume were performed, and the maximum adiabatic temperature rises and the reaction factors for each mix proportion were analyzed and suggested. The results indicated that the early strength low heat blended cement mixture had the lowest maximum adiabatic temperature rise (Q∞ and the ternary blended cement mixture had the lowest reaction factor (r. Also, Q and r varied depending on the adiabatic specimen volume even when the tests were conducted with a calorimeter, which satisfies the recommendations for adiabatic conditions. Test results show a correlation: the measurements from the 50 L specimens were consistently higher than those from the 6 L specimens. However, the Q∞ and r values of the 30 L specimen were similar to those of the 50 L specimen. Based on the above correlation, the adiabatic temperature rise of the 50 L specimen could be predicted using the results of the 6 L and 30 L specimens. Therefore, it is thought that this correlation can be used for on-site concrete quality control and basic research.
Ramsey numbers and adiabatic quantum computing
Gaitan, Frank; Clark, Lane
2011-01-01
The graph-theoretic Ramsey numbers are notoriously difficult to calculate. In fact, for the two-color Ramsey numbers $R(m,n)$ with $m,n\\geq 3$, only nine are currently known. We present a quantum algorithm for the computation of the Ramsey numbers $R(m,n)$. We show how the computation of $R(m,n)$ can be mapped to a combinatorial optimization problem whose solution can be found using adiabatic quantum evolution. We numerically simulate this adiabatic quantum algorithm and show that it correctl...
Staying adiabatic with unknown energy gap
Nehrkorn, J; Ekert, A; Smerzi, A; Fazio, R; Calarco, T
2011-01-01
We introduce an algorithm to perform an optimal adiabatic evolution that operates without an apriori knowledge of the system spectrum. By probing the system gap locally, the algorithm maximizes the evolution speed, thus minimizing the total evolution time. We test the algorithm on the Landau-Zener transition and then apply it on the quantum adiabatic computation of 3-SAT: The result is compatible with an exponential speed-up for up to twenty qubits with respect to classical algorithms. We finally study a possible algorithm improvement by combining it with the quantum Zeno effect.
Complexity of the Quantum Adiabatic Algorithm
Hen, Itay
2013-01-01
The Quantum Adiabatic Algorithm (QAA) has been proposed as a mechanism for efficiently solving optimization problems on a quantum computer. Since adiabatic computation is analog in nature and does not require the design and use of quantum gates, it can be thought of as a simpler and perhaps more profound method for performing quantum computations that might also be easier to implement experimentally. While these features have generated substantial research in QAA, to date there is still a lack of solid evidence that the algorithm can outperform classical optimization algorithms.
Adiabatic Improved Efficient Charge Recovery Logic for Low Power CMOS Logic
Directory of Open Access Journals (Sweden)
Prof. Mukesh Tiwar
2012-08-01
Full Text Available Power dissipation becoming a limiting factor in VLSI circuits and systems. Due to relatively high complexity of VLSI systems used in various applications, the power dissipation in CMOS inverter, arises from its switching activity, which is mainly influenced by the supply voltage and effective capacitance. The low-power requirements of present electronic systems have challenged the scientific research towards the study of technological, architectural and circuital solutions that allow a reduction of the energy dissipated by an electronic circuit. One of the main causes of energy dissipation in CMOS circuits is due to the charging and discharging of the node capacitances of the circuits, present both as a load and as parasitic. Such part of the total power dissipated by a circuit is called dynamic power. In order to reduce the dynamic power, an alternative approach to the traditional techniques of power consumption reduction, named adiabatic switching technique is use. Adiabatic switching is an approach to low-power digital circuits that differs fundamentally from other practical low-power techniques. The term adiabatic comes from thermodynamics, used to describe a process in which there is no exchange of heat with the environment. When adiabatic switching is used, the signal energies stored on circuit capacitances may be recycled instead of dissipated as heat. The adiabatic switching technique can achieve very low power dissipation, but at the expense of circuit complexity. Adiabatic logic offers a way to reuse the energy stored in the load capacitors rather than the traditional way of discharging the load capacitors to the ground and wasting this energy. Power reduction is achieved by recovering the energy in the recover phase of the supply clock.
Semi adiabatic theory of seasonal Markov processes
Energy Technology Data Exchange (ETDEWEB)
Talkner, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1999-08-01
The dynamics of many natural and technical systems are essentially influenced by a periodic forcing. Analytic solutions of the equations of motion for periodically driven systems are generally not known. Simulations, numerical solutions or in some limiting cases approximate analytic solutions represent the known approaches to study the dynamics of such systems. Besides the regime of weak periodic forces where linear response theory works, the limit of a slow driving force can often be treated analytically using an adiabatic approximation. For this approximation to hold all intrinsic processes must be fast on the time-scale of a period of the external driving force. We developed a perturbation theory for periodically driven Markovian systems that covers the adiabatic regime but also works if the system has a single slow mode that may even be slower than the driving force. We call it the semi adiabatic approximation. Some results of this approximation for a system exhibiting stochastic resonance which usually takes place within the semi adiabatic regime are indicated. (author) 1 fig., 8 refs.
Quantum Pumping and Adiabatic Transport in Nanostructures
Wakker, G.M.M.
2011-01-01
This thesis consists of a theoretical exploration of quantum transport phenomena and quantum dynamics in nanostructures. Specifically, we investigate adiabatic quantum pumping of charge in several novel types of nanostructures involving open quantum dots or graphene. For a bilayer of graphene we fin
Adiabatic transition probability for a tangential crossing
Watanabe, Takuya
2006-01-01
We consider a time-dependent Schrödinger equation whose Hamiltonian is a $2\\times 2$ real symmetric matrix. We study, using an exact WKB method, the adiabatic limit of the transition probability in the case where several complex eigenvalue crossing points accumulate to one real point.
Improving the positive feedback adiabatic logic familiy
Directory of Open Access Journals (Sweden)
J. Fischer
2004-01-01
Full Text Available Positive Feedback Adiabatic Logic (PFAL shows the lowest energy dissipation among adiabatic logic families based on cross-coupled transistors, due to the reduction of both adiabatic and non-adiabatic losses. The dissipation primarily depends on the resistance of the charging path, which consists of a single p-channel MOSFET during the recovery phase. In this paper, a new logic family called Improved PFAL (IPFAL is proposed, where all n- and pchannel devices are swapped so that the charge can be recovered through an n-channel MOSFET. This allows to decrease the resistance of the charging path up to a factor of 2, and it enables a significant reduction of the energy dissipation. Simulations based on a 0.13µm CMOS process confirm the improvements in terms of power consumption over a large frequency range. However, the same simple design rule, which enables in PFAL an additional reduction of the dissipation by optimal transistor sizing, does not apply to IPFAL. Therefore, the influence of several sources of dissipation for a generic IPFAL gate is illustrated and discussed, in order to lower the power consumption and achieve better performance.
Recent adiabaticity results from orbit calculations
International Nuclear Information System (INIS)
There has been much activity recently in an attempt to find a straightforward method of predicting the limits of adiabatic behavior in high-beta magnetic-mirror configurations. The particle-orbit code TIBRO was used to obtain numerical results on nonadiabatic behavior with which the predictions of theoretical expressions can be compared. These results are summarized. (MOW)
Communication: Adiabatic and non-adiabatic electron-nuclear motion: Quantum and classical dynamics
Albert, Julian; Kaiser, Dustin; Engel, Volker
2016-05-01
Using a model for coupled electronic-nuclear motion we investigate the range from negligible to strong non-adiabatic coupling. In the adiabatic case, the quantum dynamics proceeds in a single electronic state, whereas for strong coupling a complete transition between two adiabatic electronic states takes place. It is shown that in all coupling regimes the short-time wave-packet dynamics can be described using ensembles of classical trajectories in the phase space spanned by electronic and nuclear degrees of freedom. We thus provide an example which documents that the quantum concept of non-adiabatic transitions is not necessarily needed if electronic and nuclear motion is treated on the same footing.
Adiabatic and Non-adiabatic quenches in a Spin-1 Bose Einstein Condensate
Boguslawski, Matthew; Hebbe Madhusudhana, Bharath; Anquez, Martin; Robbins, Bryce; Barrios, Maryrose; Hoang, Thai; Chapman, Michael
2016-05-01
A quantum phase transition (QPT) is observed in a wide range of phenomena. We have studied the dynamics of a spin-1 ferromagnetic Bose-Einstein condensate for both adiabatic and non-adiabatic quenches through a QPT. At the quantum critical point (QCP), finite size effects lead to a non-zero gap, which makes an adiabatic quench possible through the QPT. We experimentally demonstrate such a quench, which is forbidden at the mean field level. For faster quenches through the QCP, the vanishing energy gap causes the reaction timescale of the system to diverge, preventing the system from adiabatically following the ground state. We measure the temporal evolution of the spin populations for different quench speeds and determine the exponents characterizing the scaling of the onset of excitations, which are in good agreement with the predictions of Kibble-Zurek mechanism.
The dynamic instability of adiabatic blast waves
Ryu, Dongsu; Vishniac, Ethan T.
1991-01-01
Adiabatic blastwaves, which have a total energy injected from the center E varies as t(sup q) and propagate through a preshock medium with a density rho(sub E) varies as r(sup -omega) are described by a family of similarity solutions. Previous work has shown that adiabatic blastwaves with increasing or constant postshock entropy behind the shock front are susceptible to an oscillatory instability, caused by the difference between the nature of the forces on the two sides of the dense shell behind the shock front. This instability sets in if the dense postshock layer is sufficiently thin. The stability of adiabatic blastwaves with a decreasing postshock entropy is considered. Such blastwaves, if they are decelerating, always have a region behind the shock front which is subject to convection. Some accelerating blastwaves also have such region, depending on the values of q, omega, and gamma where gamma is the adiabatic index. However, since the shock interface stabilizes dynamically induced perturbations, blastwaves become convectively unstable only if the convective zone is localized around the origin or a contact discontinuity far from the shock front. On the other hand, the contact discontinuity of accelerating blastwaves is subject to a strong Rayleigh-Taylor instability. The frequency spectra of the nonradial, normal modes of adiabatic blastwaves have been calculated. The results have been applied to the shocks propagating through supernovae envelopes. It is shown that the metal/He and He/H interfaces are strongly unstable against the Rayleigh-Taylor instability. This instability will induce mixing in supernovae envelopes. In addition the implications of this work for the evolution of planetary nebulae is discussed.
International Nuclear Information System (INIS)
Intermediate between magnetic confinement (MFE) and inertial confinement (ICF) in time and density scales is an area of research now known in the US as magnetized target fusion (MTF) and in Russian as MAGO (MAGnitnoye Obzhatiye--magnetic compression). MAGO/MTF uses a magnetic field and preheated, wall-confined plasma fusion fuel within an implodable fusion target. The magnetic field suppresses thermal conduction losses in the fuel during the target implosion and hydrodynamic compression heating process. In contrast to direct, hydrodynamic compression of initially ambient-temperature fuel (i.e., ICF), MAGO/MTF involves two steps: (a) formation of a warm (e.g., 100 eV or higher), magnetized (e.g., 100 kG) plasma within a fusion target prior to implosion; (b) subsequent quasi-adiabatic compression by an imploding pusher, of which a magnetically driven imploding liner is one example. In this paper, the authors present ongoing activities and potential future activities in this relatively unexplored area of controlled thermonuclear fusion
Perturbation to Mei symmetry and adiabatic invariants for Hamilton systems
Institute of Scientific and Technical Information of China (English)
Ding Ning; Fang Jian-Hui
2008-01-01
Based on the concept of adiabatic invariant,this paper studies the perturbation to Mei symmetry and adiabatic invariants for Hamilton systems.The exact invaxiants of Mei symmetry for the system without perturbation are given.The perturbation to Mei symmetry is discussed and the adiabatic invariants induced from the perturbation to Mei symmetry of the system are obtained.
Properties of a two stage adiabatic demagnetization refrigerator
Fukuda, H.; Ueda, S.; Arai, R.; Li, J.; Saito, A. T.; Nakagome, H.; Numazawa, T.
2015-12-01
Currently, many space missions using cryogenic temperatures are being planned. In particular, high resolution sensors such as Transition Edge Sensors need very low temperatures, below 100 mK. It is well known that the adiabatic demagnetization refrigerator (ADR) is one of most useful tools for producing ultra-low temperatures in space because it is gravity independent. We studied a continuous ADR system consisting of 4 stages and demonstrated it could provide continuous temperatures around 100 mK. However, there was some heat leakage from the power leads which resulted in reduced cooling power. Our efforts to upgrade our ADR system are presented. We show the effect of using the HTS power leads and discuss a cascaded Carnot cycle consisting of 2 ADR units.
Directory of Open Access Journals (Sweden)
Piyadeh, Fatemeh
2014-12-01
Full Text Available AA2124/25vol%MoSi2 composites were processed by two powder metallurgy routes: high energy ball milling of the reinforcement and alloy powder (B composite and wet blending with cyclohexane (W composite, both followed by extrusion to achieve full consolidation. As-extruded and heat treated composite bars were studied microstructurally and mechanically (hardness and compression tests under quasistatic loading. Microstructure and fracture profiles were observed by scanning electron microscopy and the reaction products formed in the matrix were identified by energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The results show that for both composites, the hardness of the specimens in solution and aged condition was higher than in the as-extruded condition. The hardness of the B composite was higher than that of the W composite whereas the age-hardenability of the B composite was significantly lower than that of the W composite. After heat treatments, small diffusion reaction phases appeared at the interface between matrix and reinforcements. Compressive yield strength and the ultimate strength of both composites improved considerably after the artificial ageing. The composite fracture surfaces exhibited microscopically a ductile appearance that consisted of dimples in the matrix and a fragile fracture of the MoSi2 particulates.En este trabajo se procesaron materiales compuestos AA2124/25vol% MoSi2 mediante dos rutas pulvimetalúrgicas: mezcla de refuerzo y matriz mediante molino de bolas de alta energía (compuesto B y mezcla húmeda con ciclohexano (compuesto W. Ambos polvos compuestos se consolidaron por extrusión. Los materiales recién extruidos y después de tratados térmicamente se estudiaron desde el punto de vista microestructural y mecánico (dureza y compresión bajo carga cuasiestática. Las microestructuras y los perfiles de fractura se observaron por microscopía electrónica de barrido y los productos de reacci
Adiabatic quantum simulation of quantum chemistry.
Babbush, Ryan; Love, Peter J; Aspuru-Guzik, Alán
2014-10-13
We show how to apply the quantum adiabatic algorithm directly to the quantum computation of molecular properties. We describe a procedure to map electronic structure Hamiltonians to 2-body qubit Hamiltonians with a small set of physically realizable couplings. By combining the Bravyi-Kitaev construction to map fermions to qubits with perturbative gadgets to reduce the Hamiltonian to 2-body, we obtain precision requirements on the coupling strengths and a number of ancilla qubits that scale polynomially in the problem size. Hence our mapping is efficient. The required set of controllable interactions includes only two types of interaction beyond the Ising interactions required to apply the quantum adiabatic algorithm to combinatorial optimization problems. Our mapping may also be of interest to chemists directly as it defines a dictionary from electronic structure to spin Hamiltonians with physical interactions.
Adiabatic state preparation study of methylene
Energy Technology Data Exchange (ETDEWEB)
Veis, Libor, E-mail: libor.veis@jh-inst.cas.cz; Pittner, Jiří, E-mail: jiri.pittner@jh-inst.cas.cz [J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, 18223 Prague 8 (Czech Republic)
2014-06-07
Quantum computers attract much attention as they promise to outperform their classical counterparts in solving certain type of problems. One of them with practical applications in quantum chemistry is simulation of complex quantum systems. An essential ingredient of efficient quantum simulation algorithms are initial guesses of the exact wave functions with high enough fidelity. As was proposed in Aspuru-Guzik et al. [Science 309, 1704 (2005)], the exact ground states can in principle be prepared by the adiabatic state preparation method. Here, we apply this approach to preparation of the lowest lying multireference singlet electronic state of methylene and numerically investigate preparation of this state at different molecular geometries. We then propose modifications that lead to speeding up the preparation process. Finally, we decompose the minimal adiabatic state preparation employing the direct mapping in terms of two-qubit interactions.
Adiabatic Quantum Optimization for Associative Memory Recall
Directory of Open Access Journals (Sweden)
Hadayat eSeddiqi
2014-12-01
Full Text Available Hopfield networks are a variant of associative memory that recall patterns stored in the couplings of an Ising model. Stored memories are conventionally accessed as fixed points in the network dynamics that correspond to energetic minima of the spin state. We show that memories stored in a Hopfield network may also be recalled by energy minimization using adiabatic quantum optimization (AQO. Numerical simulations of the underlying quantum dynamics allow us to quantify AQO recall accuracy with respect to the number of stored memories and noise in the input key. We investigate AQO performance with respect to how memories are stored in the Ising model according to different learning rules. Our results demonstrate that AQO recall accuracy varies strongly with learning rule, a behavior that is attributed to differences in energy landscapes. Consequently, learning rules offer a family of methods for programming adiabatic quantum optimization that we expect to be useful for characterizing AQO performance.
Quantum adiabatic evolution with energy degeneracy levels
Zhang, Qi
2016-01-01
A classical-kind phase-space formalism is developed to address the tiny intrinsic dynamical deviation from what is predicted by Wilczek-Zee theorem during quantum adiabatic evolution on degeneracy levels. In this formalism, the Hilbert space and the aggregate of degenerate eigenstates become the classical-kind phase space and a high-dimensional subspace in the phase space, respectively. Compared with the previous analogous study by a different method, the current result is qualitatively different in that the first-order deviation derived here is always perpendicular to the degeneracy subspace. A tripod-scheme Hamiltonian with two degenerate dark states is employed to illustrate the adiabatic deviation with degeneracy levels.
Ramsey numbers and adiabatic quantum computing.
Gaitan, Frank; Clark, Lane
2012-01-01
The graph-theoretic Ramsey numbers are notoriously difficult to calculate. In fact, for the two-color Ramsey numbers R(m,n) with m, n≥3, only nine are currently known. We present a quantum algorithm for the computation of the Ramsey numbers R(m,n). We show how the computation of R(m,n) can be mapped to a combinatorial optimization problem whose solution can be found using adiabatic quantum evolution. We numerically simulate this adiabatic quantum algorithm and show that it correctly determines the Ramsey numbers R(3,3) and R(2,s) for 5≤s≤7. We then discuss the algorithm's experimental implementation, and close by showing that Ramsey number computation belongs to the quantum complexity class quantum Merlin Arthur.
Thermodynamic efficiency of pumped heat electricity storage.
Thess, André
2013-09-13
Pumped heat electricity storage (PHES) has been recently suggested as a potential solution to the large-scale energy storage problem. PHES requires neither underground caverns as compressed air energy storage (CAES) nor kilometer-sized water reservoirs like pumped hydrostorage and can therefore be constructed anywhere in the world. However, since no large PHES system exists yet, and theoretical predictions are scarce, the efficiency of such systems is unknown. Here we formulate a simple thermodynamic model that predicts the efficiency of PHES as a function of the temperature of the thermal energy storage at maximum output power. The resulting equation is free of adjustable parameters and nearly as simple as the well-known Carnot formula. Our theory predicts that for storage temperatures above 400 °C PHES has a higher efficiency than existing CAES and that PHES can even compete with the efficiencies predicted for advanced-adiabatic CAES.
Adiabatic graph-state quantum computation
International Nuclear Information System (INIS)
Measurement-based quantum computation (MBQC) and holonomic quantum computation (HQC) are two very different computational methods. The computation in MBQC is driven by adaptive measurements executed in a particular order on a large entangled state. In contrast in HQC the system starts in the ground subspace of a Hamiltonian which is slowly changed such that a transformation occurs within the subspace. Following the approach of Bacon and Flammia, we show that any MBQC on a graph state with generalized flow (gflow) can be converted into an adiabatically driven holonomic computation, which we call adiabatic graph-state quantum computation (AGQC). We then investigate how properties of AGQC relate to the properties of MBQC, such as computational depth. We identify a trade-off that can be made between the number of adiabatic steps in AGQC and the norm of H-dot as well as the degree of H, in analogy to the trade-off between the number of measurements and classical post-processing seen in MBQC. Finally the effects of performing AGQC with orderings that differ from standard MBQC are investigated. (paper)
Study of CSR longitudinal bunch compression cavity
International Nuclear Information System (INIS)
The scheme of longitudinal bunch compression cavity for the Cooling Storage Ring (CSR)is an important issue. Plasma physics experiments require high density heavy ion beam and short pulsed bunch,which can be produced by non-adiabatic compression of bunch implemented by a fast compression with 90 degree rotation in the longitudinal phase space. The phase space rotation in fast compression is initiated by a fast jump of the RF-voltage amplitude. For this purpose, the CSR longitudinal bunch compression cavity, loaded with FINEMET-FT-1M is studied and simulated with MAFIA code. In this paper, the CSR longitudinal bunch compression cavity is simulated and the initial bunch length of 238U72+ with 250 MeV/u will be compressed from 200 ns to 50 ns.The construction and RF properties of the CSR longitudinal bunch compression cavity are simulated and calculated also with MAFIA code. The operation frequency of the cavity is 1.15 MHz with peak voltage of 80 kV, and the cavity can be used to compress heavy ions in the CSR. (authors)
Progress in the Development of a Continuous Adiabatic Demagnetization Refrigerator
Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Jackson, Michael; King, Todd; Tuttle, James; Krebs, Carolyn A. (Technical Monitor)
2002-01-01
We report on recent progress in the development of a continuous adiabatic demagnetization refrigerator (CADR). Continuous operation avoids the constraints of long hold times and short recycle times that lead to the generally large mass of single-shot ADRs, allowing us to achieve an order of magnitude larger cooling power per unit mass. Our current design goal is 10 micro W of cooling at 50 mK using a 6-10 K heat sink. The estimated mass is less than 10 kg, including magnetic shielding of each stage. The relatively high heat rejection capability allows it to operate with a mechanical cryocooler as part of a cryogen-free, low temperature cooling system. This has the advantages of long mission life and reduced complexity and cost. We have assembled a three-stage CADR and have demonstrated continuous cooling using a superfluid helium bath as the heat sink. The temperature stability is 8 micro K rms or better over the entire cycle, and the cooling power is 2.5 micro W at 60 mK rising to 10 micro W at 100 mK.
Adiabatic calorimetric decomposition studies of 50 wt.% hydroxylamine/water.
Cisneros, L O; Rogers, W J; Mannan, M S
2001-03-19
Calorimetric data can provide a basis for determining potential hazards in reactions, storage, and transportation of process chemicals. This work provides calorimetric data for the thermal decomposition behavior in air of 50wt.% hydroxylamine/water (HA), both with and without added stabilizers, which was measured in closed cells with an automatic pressure tracking adiabatic calorimeter (APTAC). Among the data provided are onset temperatures, reaction order, activation energies, pressures of noncondensable products, thermal stability at 100 degrees C, and the effect of HA storage time. Discussed also are the catalytic effects of carbon steel, stainless steel, stainless steel with silica coating, inconel, titanium, and titanium with silica coating on the reaction self-heat rates and onset temperatures. In borosilicate glass cells, HA was relatively stable at temperatures up to 133 degrees C, where the HA decomposition self-heat rate reached 0.05 degrees C/min. The added stabilizers appeared to reduce HA decomposition rates in glass cells and at ambient temperatures. The tested metals and metal surfaces coated with silica acted as catalysts to lower the onset temperatures and increase the self-heat rates.
Jaffe, Arthur; Wozniakowski, Alex
2016-01-01
In a previous paper we introduced holographic software for quantum networks, inspired by work on planar para algebras. This software suggests the definition of a compressed transformation. Here we utilize the software to find a CT protocol to teleport compressed transformations. This protocol serves multiple parties with multiple persons.
Energy Technology Data Exchange (ETDEWEB)
Smalyuk, V. A.; Robey, H. F.; Döppner, T.; Jones, O. S.; Milovich, J. L.; Bachmann, B.; Baker, K. L.; Berzak Hopkins, L. F.; Bond, E.; Callahan, D. A.; Casey, D. T.; Celliers, P. M.; Cerjan, C.; Clark, D. S.; Dixit, S. N.; Edwards, M. J.; Haan, S. W.; Hamza, A. V.; Hurricane, O. A.; Jancaitis, K. S. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others
2015-08-15
Radiation-driven, layered deuterium-tritium plastic capsule implosions were carried out using a new, 3-shock “adiabat-shaped” drive on the National Ignition Facility. The purpose of adiabat shaping is to use a stronger first shock, reducing hydrodynamic instability growth in the ablator. The shock can decay before reaching the deuterium-tritium fuel leaving it on a low adiabat and allowing higher fuel compression. The fuel areal density was improved by ∼25% with this new drive compared to similar “high-foot” implosions, while neutron yield was improved by more than 4 times, compared to “low-foot” implosions driven at the same compression and implosion velocity.
Soft electrons as a possible heat source for Jupiter's thermosphere
Hunten, D. M.; Dessler, A. J.
1977-01-01
The 850 K exospheric temperature inferred for Jupiter from the radio-occultation experiments on Pioneers 10 and 11 is shown to imply a heat input of 0.25-0.5 erg/sq cm/sec. One possible source of this energy is precipitation of electrons from a warm plasma (temperature corresponding to energies of the order of 30-500 eV). A mechanism is suggested wherein the presence of this plasma can be accounted for by centrifugal acceleration and adiabatic compression of ionospheric electrons and protons. Present ideas of the source strength of ionospheric plasma, however, give heating rates that are too small by one to two orders of magnitude, although inferences from direct plasma measurements suggest that the required plasma is indeed present.
International Nuclear Information System (INIS)
Graphical abstract: To improve the performance of the air-cooled type absorption refrigeration, a novel non-adiabatic absorber has been applied in the cycle. Simulation results show that low grade energy is applicable for NH3/NaSCN and NH3/LiNO3 absorption refrigeration system under air cooling condition and relatively high system performance can be obtained. - Highlights: • We analyze an absorption refrigeration cycle driven by low grade energy. • Working fluids thermophysical property correlations are corrected. • Influence of non-adiabatic absorber on system performance is investigated. • We propose system operation parameters under air-cooled condition. - Abstract: An air-cooled type absorption refrigeration cycle using ammonia–lithium nitrate and ammonia–sodium thiocyanate solutions as working fluids are thermodynamically studied in this paper. In the case of many occasions especially small cooling capacity occasion where water cooling is restricted or inconvenient, application of conventional adiabatic absorbers in air-cooled type absorption refrigeration system has been studied by many investigators. Comparing to the adiabatic absorber, a novel air-cooled non-adiabatic absorber is applied to the absorption refrigeration system in this study to improve system performance. It is shown that, system performance has a significant improvement when temperatures of rich ammonia solution at the outlet of absorber decrease under the effect of the heat dissipation capacity of the non-adiabatic absorber. Another advantage is that heat load of the system heat exchangers including generator, solution heat exchanger and air-cooler, decreases with the solution temperature decrease at the outlet of the absorber under the same system cooling capacity condition, which brings benefits to the system cost reduction. Variation of system performance and other system operation parameters with generator temperature, absorption temperature and absorption efficiency has
Magnetic compression of an FRC plasma
Energy Technology Data Exchange (ETDEWEB)
Okada, S.; Kitano, K.; Matsumoto, H. [Plasma Physics Laboratory, Faculty of Engineering, Osaka Univ., Suita, Osaka (JP)] [and others
1999-04-01
Confinement of a plasma with field-reversed configuration (FRC) is predicted to be improved if it is compressed only axially, keeping the magnetic flux between the separatrix and the confining chamber (flux conserver) wall unchanged, while allowing the plasma to expand radially. The prediction is based on an empirical scaling law of FRC confinement and on the assumption that the compression is done adiabatically. The apparatus for this axial compression was developed and the axial compression experiment was actually carried out by decreasing the distance of the mirror fields between which the FRC plasma is confined by 30% and the plasma life time of about 500 {mu}s was increased by about 50 {mu}s. (author)
Free Convective Unsteady MHD Flow of Newtonian Fluid in a Channel with Adiabatic
Directory of Open Access Journals (Sweden)
Dr.G.Prabhakararao
2014-07-01
Full Text Available In this paper, we investigated an unsteady free convection MHD flow of an incompressible viscous electrically conducting fluid under the action of transverse uniform magnetic field between two heated vertical plates by keeping one plate is adiabatic. The governing equations of velocity and temperature fields with appropriate boundary conditions are solved by using perturbation technique. The effects of various physical parameters on the velocity and temperature fields are discussed in detail with the help of graphs.
Non-adiabatic effects in near-adiabatic mixed-field orientation and alignment
Maan, Anjali; Ahlawat, Dharamvir Singh; Prasad, Vinod
2016-11-01
We present a theoretical study of the impact of a pair of moderate electric fields tilted an angle with respect to one another on a molecule. As a prototype, we consider a molecule with large rotational constant (with corresponding small rotational period) and moderate dipole moment. Within rigid-rotor approximation, the time-dependent Schrodinger equation is solved using fourth-order Runge-Kutta method. We have analysed that lower rotational states are significantly influenced by variation in pulse durations, the tilt angle between the fields and also on the electric field strengths. We also suggest a control scheme of how the rotational dynamics, orientation and alignment of a molecule can be enhanced by a combination of near-adiabatic pulses in comparision to non-adiabatic or adiabatic pulses.
Institute of Scientific and Technical Information of China (English)
王学滨
2004-01-01
A method for calculation of temperature distribution in adiabatic shear band is proposed in terms of gradient-dependent plasticity where the characteristic length describes the interactions and interplaying among microstructures. First, the increment of the plastic shear strain distribution in adiabatic shear band is obtained based on gradient-dependent plasticity. Then, the plastic work distribution is derived according to the current flow shear stress and the obtained increment of plastic shear strain distribution. In the light of the well-known assumption that 90% of plastic work is converted into the heat resulting in increase in temperature in adiabatic shear band, the increment of the temperature distribution is presented. Next, the average temperature increment in the shear band is calculated to compute the change in flow shear stress due to the thermal softening effect. After the actual flow shear stress considering the thermal softening effect is obtained according to the Johnson-Cook constitutive relation, the increment of the plastic shear strain distribution, the plastic work and the temperature in the next time step are recalculated until the total time is consumed. Summing the temperature distribution leads to rise in the total temperature distribution. The present calculated maximum temperature in adiabatic shear band in titanium agrees with the experimental observations. Moreover, the temperature profiles for different flow shear stresses are qualitatively consistent with experimental and numerical results. Effects of some related parameters on the temperature distribution are also predicted.
Impact of Turbocharger Non-Adiabatic Operation on Engine Volumetric Efficiency and Turbo Lag
Directory of Open Access Journals (Sweden)
S. Shaaban
2012-01-01
Full Text Available Turbocharger performance significantly affects the thermodynamic properties of the working fluid at engine boundaries and hence engine performance. Heat transfer takes place under all circumstances during turbocharger operation. This heat transfer affects the power produced by the turbine, the power consumed by the compressor, and the engine volumetric efficiency. Therefore, non-adiabatic turbocharger performance can restrict the engine charging process and hence engine performance. The present research work investigates the effect of turbocharger non-adiabatic performance on the engine charging process and turbo lag. Two passenger car turbochargers are experimentally and theoretically investigated. The effect of turbine casing insulation is also explored. The present investigation shows that thermal energy is transferred to the compressor under all circumstances. At high rotational speeds, thermal energy is first transferred to the compressor and latter from the compressor to the ambient. Therefore, the compressor appears to be “adiabatic” at high rotational speeds despite the complex heat transfer processes inside the compressor. A tangible effect of turbocharger non-adiabatic performance on the charging process is identified at turbocharger part load operation. The turbine power is the most affected operating parameter, followed by the engine volumetric efficiency. Insulating the turbine is recommended for reducing the turbine size and the turbo lag.
How AGN Jets Heat the Intracluster Medium—Insights from Hydrodynamic Simulations
Yang, H.-Y. Karen; Reynolds, Christopher S.
2016-10-01
Feedback from active galactic nuclei (AGNs) is believed to prevent catastrophic cooling in galaxy clusters. However, how the feedback energy is transformed into heat, and how the AGN jets heat the intracluster medium (ICM) isotropically, still remain elusive. In this work, we gain insights into the relative importance of different heating mechanisms using three-dimensional hydrodynamic simulations including cold gas accretion and momentum-driven jet feedback, which are the most successful models to date in terms of reproducing the properties of cool cores. We find that there is net heating within two “jet cones” (within ∼30° from the axis of jet precession) where the ICM gains entropy by shock heating and mixing with the hot thermal gas within bubbles. Outside the jet cones, the ambient gas is heated by weak shocks, but not enough to overcome radiative cooling, therefore, forming a “reduced” cooling flow. Consequently, the cluster core is in a process of “gentle circulation” over billions of years. Within the jet cones, there is significant adiabatic cooling as the gas is uplifted by buoyantly rising bubbles; outside the cones, energy is supplied by the inflow of already-heated gas from the jet cones as well as adiabatic compression as the gas moves toward the center. In other words, the fluid dynamics self-adjusts such that it compensates and transports the heat provided by the AGN, and hence no fine-tuning of the heating profile of any process is necessary. Throughout the cluster evolution, turbulent energy is only at the percent level compared to gas thermal energy, and thus turbulent heating is not the main source of heating in our simulation.
Bond selective chemistry beyond the adiabatic approximation
Energy Technology Data Exchange (ETDEWEB)
Butler, L.J. [Univ. of Chicago, IL (United States)
1993-12-01
One of the most important challenges in chemistry is to develop predictive ability for the branching between energetically allowed chemical reaction pathways. Such predictive capability, coupled with a fundamental understanding of the important molecular interactions, is essential to the development and utilization of new fuels and the design of efficient combustion processes. Existing transition state and exact quantum theories successfully predict the branching between available product channels for systems in which each reaction coordinate can be adequately described by different paths along a single adiabatic potential energy surface. In particular, unimolecular dissociation following thermal, infrared multiphoton, or overtone excitation in the ground state yields a branching between energetically allowed product channels which can be successfully predicted by the application of statistical theories, i.e. the weakest bond breaks. (The predictions are particularly good for competing reactions in which when there is no saddle point along the reaction coordinates, as in simple bond fission reactions.) The predicted lack of bond selectivity results from the assumption of rapid internal vibrational energy redistribution and the implicit use of a single adiabatic Born-Oppenheimer potential energy surface for the reaction. However, the adiabatic approximation is not valid for the reaction of a wide variety of energetic materials and organic fuels; coupling between the electronic states of the reacting species play a a key role in determining the selectivity of the chemical reactions induced. The work described below investigated the central role played by coupling between electronic states in polyatomic molecules in determining the selective branching between energetically allowed fragmentation pathways in two key systems.
Adiabatic Regularization for Gauge Field and the Conformal Anomaly
Chu, Chong-Sun
2016-01-01
We construct and provide the adiabatic regularization method for a $U(1)$ gauge field in a conformally flat spacetime by quantizing in the canonical formalism the gauge fixed $U(1)$ theory with mass terms for the gauge fields and the ghost fields. We show that the adiabatic expansion for the mode functions and the adiabatic vacuum can be defined in a similar way using WKB-type solutions as the scalar fields. As an application of the adiabatic method, we compute the trace of the energy momentum tensor and reproduces the known result for the conformal anomaly obtained by the other regularization methods. The availability of the adiabatic expansion scheme for gauge field allows one to study the renormalization of the de-Sitter space maximal superconformal Yang-Mills theory using the adiabatic regularization method.
Accuracy vs run time in adiabatic quantum search
Rezakhani, A T; Lidar, D A
2010-01-01
Adiabatic quantum algorithms are characterized by their run time and accuracy. The relation between the two is essential for quantifying adiabatic algorithmic performance, yet is often poorly understood. We study the dynamics of a continuous time, adiabatic quantum search algorithm, and find rigorous results relating the accuracy and the run time. Proceeding with estimates, we show that under fairly general circumstances the adiabatic algorithmic error exhibits a behavior with two discernible regimes: the error decreases exponentially for short times, then decreases polynomially for longer times. We show that the well known quadratic speedup over classical search is associated only with the exponential error regime. We illustrate the results through examples of evolution paths derived by minimization of the adiabatic error. We also discuss specific strategies for controlling the adiabatic error and run time.
Adiabatic quantum algorithm for search engine ranking
Garnerone, Silvano; Lidar, Daniel A
2011-01-01
We propose an adiabatic quantum algorithm to evaluate the PageRank vector, the most widely used tool in ranking the relative importance of internet pages. We present extensive numerical simulations which provide evidence that this quantum algorithm outputs any component of the PageRank vector-and thus the ranking of the corresponding webpage-in a time which scales polylogarithmically in the number of webpages. This would constitute an exponential speed-up with respect to all known classical algorithms designed to evaluate the PageRank.
On adiabatic perturbations in the ekpyrotic scenario
Linde, A.; Mukhanov, V.; Vikman, A.
2010-02-01
In a recent paper, Khoury and Steinhardt proposed a way to generate adiabatic cosmological perturbations with a nearly flat spectrum in a contracting Universe. To produce these perturbations they used a regime in which the equation of state exponentially rapidly changed during a short time interval. Leaving aside the singularity problem and the difficult question about the possibility to transmit these perturbations from a contracting Universe to the expanding phase, we will show that the methods used in Khoury are inapplicable for the description of the cosmological evolution and of the process of generation of perturbations in this scenario.
On adiabatic perturbations in the ekpyrotic scenario
Linde, A; Vikman, A
2009-01-01
In a recent paper arXiv:0910.2230, Khoury and Steinhardt proposed a way to generate adiabatic cosmological perturbations with a nearly flat spectrum in a contracting Universe. To produce these perturbations they used a regime in which the equation of state exponentially rapidly changed during a short time interval. Leaving aside the singularity problem and the difficult question about the possibility to transmit these perturbations from a contracting Universe to the expanding phase, we will show that the methods used in arXiv:0910.2230 are inapplicable for the description of the cosmological evolution and of the process of generation of perturbations in this scenario.
Adiabatic chaos in the spin orbit problem
Benettin, Giancarlo; Guzzo, Massimiliano; Marini, Valerio
2008-05-01
We provide evidences that the angular momentum of a symmetric rigid body in a spin orbit resonance can perform large scale chaotic motions on time scales which increase polynomially with the inverse of the oblateness of the body. This kind of irregular precession appears as soon as the orbit of the center of mass is non-circular and the angular momentum of the body is far from the principal directions with minimum (maximum) moment of inertia. We also provide a quantitative explanation of these facts by using the theory of adiabatic invariants, and we provide numerical applications to the cases of the 1:1 and 1:2 spin orbit resonances.
Hypergraph Ramsey Numbers and Adiabatic Quantum Algorithm
Qu, Ri; Bao, Yan-ru
2012-01-01
Gaitan and Clark [Phys. Rev. Lett. 108, 010501 (2012)] have recently presented a quantum algorithm for the computation of the Ramsey numbers R(m, n) using adiabatic quantum evolution. We consider that the two-color Ramsey numbers R(m, n; r) for r-uniform hypergraphs can be computed by using the similar ways in [Phys. Rev. Lett. 108, 010501 (2012)]. In this comment, we show how the computation of R(m, n; r) can be mapped to a combinatorial optimization problem whose solution be found using adi...
Generalized Ramsey numbers through adiabatic quantum optimization
Ranjbar, Mani; Macready, William G.; Clark, Lane; Gaitan, Frank
2016-09-01
Ramsey theory is an active research area in combinatorics whose central theme is the emergence of order in large disordered structures, with Ramsey numbers marking the threshold at which this order first appears. For generalized Ramsey numbers r( G, H), the emergent order is characterized by graphs G and H. In this paper we: (i) present a quantum algorithm for computing generalized Ramsey numbers by reformulating the computation as a combinatorial optimization problem which is solved using adiabatic quantum optimization; and (ii) determine the Ramsey numbers r({{T}}m,{{T}}n) for trees of order m,n = 6,7,8, most of which were previously unknown.
Adiabatic fission barriers in superheavy nuclei
Jachimowicz, P.; Kowal, M; Skalski, J.
2016-01-01
Using the microscopic-macroscopic model based on the deformed Woods-Saxon single-particle potential and the Yukawa-plus-exponential macroscopic energy we calculated static fission barriers $B_{f}$ for 1305 heavy and superheavy nuclei $98\\leq Z \\leq 126$, including even - even, odd - even, even - odd and odd - odd systems. For odd and odd-odd nuclei, adiabatic potential energy surfaces were calculated by a minimization over configurations with one blocked neutron or/and proton on a level from ...
A quantum search algorithm based on partial adiabatic evolution
Institute of Scientific and Technical Information of China (English)
Zhang Ying-Yu; Hu He-Ping; Lu Song-Feng
2011-01-01
This paper presents and implements a specified partial adiabatic search algorithm on a quantum circuit. It studies the minimum energy gap between the first excited state and the ground state of the system Hamiltonian and it finds that, in the case of M=1, the algorithm has the same performance as the local adiabatic algorithm. However, the algorithm evolves globally only within a small interval, which implies that it keeps the advantages of global adiabatic algorithms without losing the speedup of the local adiabatic search algorithm.
Magnesium Diboride Superconducting Coils for Adiabatic Demagnetization Refrigerators (ADR's) Project
National Aeronautics and Space Administration — For Adiabatic Demagnetization Refrigerators (ADRs) in space applications, it is desirable to have very light weight, small diameter, high current density...
Brodowicz, Kazimierz; Wyszynski, M L; Wyszynski
2013-01-01
Heat pumps and related technology are in widespread use in industrial processes and installations. This book presents a unified, comprehensive and systematic treatment of the design and operation of both compression and sorption heat pumps. Heat pump thermodynamics, the choice of working fluid and the characteristics of low temperature heat sources and their application to heat pumps are covered in detail.Economic aspects are discussed and the extensive use of the exergy concept in evaluating performance of heat pumps is a unique feature of the book. The thermodynamic and chemical properties o
Potential and Evolution of Compressed Air Energy Storage: Energy and Exergy Analyses
Directory of Open Access Journals (Sweden)
Young-Min Kim
2012-08-01
Full Text Available Energy storage systems are increasingly gaining importance with regard to their role in achieving load levelling, especially for matching intermittent sources of renewable energy with customer demand, as well as for storing excess nuclear or thermal power during the daily cycle. Compressed air energy storage (CAES, with its high reliability, economic feasibility, and low environmental impact, is a promising method for large-scale energy storage. Although there are only two large-scale CAES plants in existence, recently, a number of CAES projects have been initiated around the world, and some innovative concepts of CAES have been proposed. Existing CAES plants have some disadvantages such as energy loss due to dissipation of heat of compression, use of fossil fuels, and dependence on geological formations. This paper reviews the main drawbacks of the existing CAES systems and presents some innovative concepts of CAES, such as adiabatic CAES, isothermal CAES, micro-CAES combined with air-cycle heating and cooling, and constant-pressure CAES combined with pumped hydro storage that can address such problems and widen the scope of CAES applications, by energy and exergy analyses. These analyses greatly help us to understand the characteristics of each CAES system and compare different CAES systems.
International Nuclear Information System (INIS)
The temperature dependences of thermal expansion and isothermal compression of (TiGaSe3)0.9(TiInS3)0.1 and (TiGaSe2)0.8(TiInS2)0.2 are investigated. The heat capacity difference at constant pressure and volume is calculated on the base of experimental data. It is established that interactions which are connected with the increase of defect number and weakening of chemical bond in lattice, increases with temperature increase and increase of tiInS2 content in composition
Severe plastic deformation through adiabatic shear banding in Fe-C steels
Energy Technology Data Exchange (ETDEWEB)
Lesuer, D; Syn, C; Sherby, O
2004-12-01
Severe plastic deformation is observed within adiabatic shear bands in iron-carbon steels. These shear bands form under high strain rate conditions, in excess of 1000 s{sup -1}, and strains in the order 5 or greater are commonly observed. Studies on shear band formation in a ultrahigh carbon steel (1.3%C) are described in the pearlitic condition. A hardness of 11.5 GPa (4600 MPa) is obtained within the band. A mechanism is described to explain the high strength based on phase transformation to austenite from adiabatic heating resulting from severe deformation. Rapid re-transformation leads to an ultra-fine ferrite grain size containing carbon principally in the form of nanosize carbides. It is proposed that the same mechanism explains the ultrahigh strength of iron-carbon steels observed in ball-milling, ball drop tests and in severely deformed wires.
Performance of Indirectly-Driven Capsule Implosions on NIF Using Adiabat-Shaping
Robey, Harry
2015-11-01
Indirectly-driven capsule implosions are being conducted on the National Ignition Facility (NIF). Early experiments conducted during the National Ignition Campaign (NIC) were driven by a laser pulse with a relatively low-power initial foot (``low-foot''), which was designed to keep the deuterium-tritium (DT) fuel on a low adiabat to achieve a high fuel areal density (ρR). These implosions were successful in achieving high ρR, but fell significantly short of the predicted neutron yield. A leading candidate to explain this degraded performance was ablation front instability growth, which can lead to the mixing of ablator material with the DT fuel layer and in extreme cases into the central DT hot spot. A subsequent campaign employing a modified laser pulse with increased power in the foot (``high-foot'') was designed to reduce the adverse effects of ablation front instability growth. These implosions have been very successful, increasing neutron yields by more than an order of magnitude, but at the expense of reduced fuel compression. To bridge these two regimes, a series of implosions have been designed to simultaneously achieve both high stability and high ρR. These implosions employ adiabat-shaping, where the driving laser pulse is high in the initial picket similar to the high-foot to retain the favorable stability properties at the ablation front. The remainder of the foot is similar to that of the low-foot, driving a lower velocity shock into the DT fuel to keep the adiabat low and compression high. This talk will present results and analysis of these implosions and will discuss implications for improved implosion performance. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
An analysis of ullage heat transfer in the orbital refueling system
Kauffman, D.
1986-07-01
The Orbital Refueling System was an experiment flown on Shuttle Mission STS 41-G in October, 1984. Liquid hydrazine fuel was transferred back and forth from one spherical bladder tank to another using pressurized nitrogen as the driving force. Compressive heating of the ullage gas in the receiving tank could lead to a hazardous situation if any hydrazine leaked through to the ullage side of the bladder and was heated above about 175 F, where it can undergo spontaneous exothermic decomposition. Early analysis of the flight data indicated that the ullage compression process was much closer to an isothermal than an adiabatic one. In this study, a thorough review of the pertinent literature was used to make an a priori best-estimate for the ullage gas heat transfer coefficient (defining the Nusselt Number as a function of Reynolds and Rayleigh Numbers). Experimental data from the flight were analyzed in detail. It is evident that there is considerably more heat transfer than can be accounted for by conduction alone, but the observed increases do not correlate well with Reynolds Number, Rayleigh Number or vehicle acceleration. There are large gaps in the present understanding of convective heat transfer in closed containers with internal heat generation, especially in the presence of vibrations or other random disturbances. A program of experiments to fill in these gaps is suggested, covering both ground and orbital environments.
Thermal explosion hazards on 18650 lithium ion batteries with a VSP2 adiabatic calorimeter
Energy Technology Data Exchange (ETDEWEB)
Jhu, Can-Yong [Doctoral Program, Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology (NYUST), 123, University Rd., Sec. 3, Douliou, Yunlin 64002, Taiwan, ROC (China); Wang, Yih-Wen, E-mail: g9410825@yuntech.edu.tw [Department of Occupational Safety and Health, Jen-Teh Junior College of Medicine, Nursing and Management, 79-9, Sha-Luen-Hu, Xi-Zhou-Li, Houlong, Miaoli 35664, Taiwan, ROC (China); Shu, Chi-Min [Doctoral Program, Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology (NYUST), 123, University Rd., Sec. 3, Douliou, Yunlin 64002, Taiwan, ROC (China); Chang, Jian-Chuang; Wu, Hung-Chun [Material and Chemical Research Laboratories, Industrial Technology Research Institute (ITRI), Rm. 222, Bldg. 77, 2F, 195, Sec. 4, Chung Hsing Rd., Chutung, Hsinchu 31040, Taiwan, ROC (China)
2011-08-15
Thermal abuse behaviors relating to adiabatic runaway reactions in commercial 18650 lithium ion batteries (LiCoO{sub 2}) are being studied in an adiabatic calorimeter, vent sizing package 2 (VSP2). We select four worldwide battery producers, Sony, Sanyo, Samsung and LG, and tested their Li-ion batteries, which have LiCoO{sub 2} cathodes, to determine their thermal instabilities and adiabatic runaway features. The charged (4.2 V) and uncharged (3.7 V) 18650 Li-ion batteries are tested using a VSP2 with a customized stainless steel test can to evaluate their thermal hazard characteristics, such as the initial exothermic temperature (T{sub 0}), the self-heating rate (dT/dt), the pressure rise rate (dP/dt), the pressure-temperature profiles and the maximum temperature (T{sub max}) and pressure (P{sub max}). The T{sub max} and P{sub max} of the charged Li-ion battery during the runaway reaction reach 903.0 {sup o}C and 1565.9 psig (pound-force per square inch gauge), respectively. This result leads to a thermal explosion, and the heat of reaction is 26.2 kJ. The thermokinetic parameters of the reaction of LiCoO{sub 2} batteries are also determined using the Arrhenius model. The thermal reaction mechanism of the Li-ion battery (pack) proved to be an important safety concern for energy storage. Additionally, use of the VSP2 to classify the self-reactive ratings of the various Li-ion batteries demonstrates a new application of the adiabatic calorimetric methodology.
Plasmas in particle accelerators: adiabatic theories for bunched beams
International Nuclear Information System (INIS)
Three different formalisms for discussing Vlasov's equation for bunched beam problems with anharmonic space charge forces are outlined. These correspond to the use of a drift kinetic equation averaged over random betatron motions; a fluidkinetic adiabatic regime analogous to the theory of Chew, Goldberger, and Low; and an adiabatic hydrodynamic theory
High Fidelity Adiabatic Quantum Computation via Dynamical Decoupling
Quiroz, Gregory
2012-01-01
We introduce high-order dynamical decoupling strategies for open system adiabatic quantum computation. Our numerical results demonstrate that a judicious choice of high-order dynamical decoupling method, in conjunction with an encoding which allows computation to proceed alongside decoupling, can dramatically enhance the fidelity of adiabatic quantum computation in spite of decoherence.
Quantum adiabatic algorithm for factorization and its experimental implementation.
Peng, Xinhua; Liao, Zeyang; Xu, Nanyang; Qin, Gan; Zhou, Xianyi; Suter, Dieter; Du, Jiangfeng
2008-11-28
We propose an adiabatic quantum algorithm capable of factorizing numbers, using fewer qubits than Shor's algorithm. We implement the algorithm in a NMR quantum information processor and experimentally factorize the number 21. In the range that our classical computer could simulate, the quantum adiabatic algorithm works well, providing evidence that the running time of this algorithm scales polynomially with the problem size. PMID:19113467
Teleportation of an Unknown Atomic State via Adiabatic Passage
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We propose a scheme for teleporting an unknown atomic state via adiabatic passage. Taking advantage of adiabatic passage, the atom has no probability of being excited and thus the atomic spontaneous emission is suppressed.We also show that the fidelity can reach 1 under certain condition.
Examination of the adiabatic approximation in open systems
International Nuclear Information System (INIS)
We examine the notion of the adiabatic approximation in open systems by applying it to closed systems. Our results shows that the notion is equivalent to the standard adiabatic approximation if the systems are initially in eigenstates, and it leads to a more general expression if the systems are in mixed states
Effect of Post-Heat Treatment on Dimensional Stability of Compressed Wood%后期热处理对压缩木尺寸稳定性的影响
Institute of Scientific and Technical Information of China (English)
陈太安; 蒋明; 王昌命; 高力勇
2011-01-01
The timber of Pinus armandii and Alnus cremastogyne was experimented to evaluate the dimensional stability by taking thickness swelling ( TS) as the major evaluation index after the compressed wood was individually treated under 170℃ and 210℃ for 2 h with the heated air or conductive oil heat transfer media. The results showed that both of the moisture-uptake and water-uptake of the compressed wood could be reduced by post heat-treating, so the dimensional stability of the compressed wood was improved. The conductive oil treatment had better effect than that of the hot air, while the treatment effect under 210℃ was better than that of under 170℃. The best technological condition was conductive oil treatment under 210℃, which could reduce moisture uptake TS index by 50% while reduce TS value after 24 h water uptake by 85%. The results also showed that the effect of heat treatment varied with tree species, The heat treatment effect on Pinus armandii wood was better than that of on Alnus cremastogyne wood.%以华山松和西南桤木为研究试材,以热空气和导热油为加热介质,在温度为170℃和210℃时分别对2种压缩木进行2 h的热处理,以厚度膨胀率为主要指标评价其尺寸稳定性.结果表明:后期热处理可以降低压缩木吸湿率和吸水率,改善压缩木的尺寸稳定性,油浴处理的效果优于热空气处理,210℃处理效果优于170℃；在所有工艺条件中,以210℃油浴处理效果最佳,可使吸湿厚度膨胀率下降50％左右,使24h吸水厚度膨胀率减小85％左右；热处理对树种具有一定的选择性,对西南桤木的效果略优于华山松.
Conformal Symmetries of Adiabatic Modes in Cosmology
Hinterbichler, Kurt; Khoury, Justin
2012-01-01
We remark on the existence of non-linearly realized conformal symmetries for scalar adiabatic perturbations in cosmology. These conformal symmetries are present for any cosmological background, beyond any slow-roll or quasi-de Sitter approximation. The dilatation transformation shifts the curvature perturbation by a constant, and corresponds to the well-known symmetry under spatial rescaling. We argue that the scalar sector is also invariant under special conformal transformations, which shift the curvature perturbation by a term linear in the spatial coordinates. We discuss whether these conformal symmetries can be extended to include tensor perturbations. Tensor modes introduce their own set of non-linearly realized symmetries. We identify an infinite set of large gauge transformations which maintain the transverse, traceless gauge condition, while shifting the tensor mode non-trivially.
Adiabatic theory for anisotropic cold molecule collisions
International Nuclear Information System (INIS)
We developed an adiabatic theory for cold anisotropic collisions between slow atoms and cold molecules. It enables us to investigate the importance of the couplings between the projection states of the rotational motion of the atom about the molecular axis of the diatom. We tested our theory using the recent results from the Penning ionization reaction experiment 4He(1s2s 3S) + HD(1s2) → 4He(1s2) + HD+(1s) + e− [Lavert-Ofir et al., Nat. Chem. 6, 332 (2014)] and demonstrated that the couplings have strong effect on positions of shape resonances. The theory we derived provides cross sections which are in a very good agreement with the experimental findings
Adiabatic theory for anisotropic cold molecule collisions.
Pawlak, Mariusz; Shagam, Yuval; Narevicius, Edvardas; Moiseyev, Nimrod
2015-08-21
We developed an adiabatic theory for cold anisotropic collisions between slow atoms and cold molecules. It enables us to investigate the importance of the couplings between the projection states of the rotational motion of the atom about the molecular axis of the diatom. We tested our theory using the recent results from the Penning ionization reaction experiment (4)He(1s2s (3)S) + HD(1s(2)) → (4)He(1s(2)) + HD(+)(1s) + e(-) [Lavert-Ofir et al., Nat. Chem. 6, 332 (2014)] and demonstrated that the couplings have strong effect on positions of shape resonances. The theory we derived provides cross sections which are in a very good agreement with the experimental findings. PMID:26298122
Adiabatic theory for anisotropic cold molecule collisions
Energy Technology Data Exchange (ETDEWEB)
Pawlak, Mariusz [Schulich Faculty of Chemistry, Technion–Israel Institute of Technology, Haifa 32000 (Israel); Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń (Poland); Shagam, Yuval; Narevicius, Edvardas [Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Moiseyev, Nimrod [Schulich Faculty of Chemistry, Technion–Israel Institute of Technology, Haifa 32000 (Israel); Faculty of Physics, Technion–Israel Institute of Technology, Haifa 32000 (Israel)
2015-08-21
We developed an adiabatic theory for cold anisotropic collisions between slow atoms and cold molecules. It enables us to investigate the importance of the couplings between the projection states of the rotational motion of the atom about the molecular axis of the diatom. We tested our theory using the recent results from the Penning ionization reaction experiment {sup 4}He(1s2s {sup 3}S) + HD(1s{sup 2}) → {sup 4}He(1s{sup 2}) + HD{sup +}(1s) + e{sup −} [Lavert-Ofir et al., Nat. Chem. 6, 332 (2014)] and demonstrated that the couplings have strong effect on positions of shape resonances. The theory we derived provides cross sections which are in a very good agreement with the experimental findings.
Number Partitioning via Quantum Adiabatic Computation
Smelyanskiy, Vadim N.; Toussaint, Udo; Clancy, Daniel (Technical Monitor)
2002-01-01
We study both analytically and numerically the complexity of the adiabatic quantum evolution algorithm applied to random instances of combinatorial optimization problems. We use as an example the NP-complete set partition problem and obtain an asymptotic expression for the minimal gap separating the ground and exited states of a system during the execution of the algorithm. We show that for computationally hard problem instances the size of the minimal gap scales exponentially with the problem size. This result is in qualitative agreement with the direct numerical simulation of the algorithm for small instances of the set partition problem. We describe the statistical properties of the optimization problem that are responsible for the exponential behavior of the algorithm.
An Integrated Development Environment for Adiabatic Quantum Programming
Energy Technology Data Exchange (ETDEWEB)
Humble, Travis S [ORNL; McCaskey, Alex [ORNL; Bennink, Ryan S [ORNL; Billings, Jay Jay [ORNL; D' Azevedo, Eduardo [ORNL; Sullivan, Blair D [ORNL; Klymko, Christine F [ORNL; Seddiqi, Hadayat [ORNL
2014-01-01
Adiabatic quantum computing is a promising route to the computational power afforded by quantum information processing. The recent availability of adiabatic hardware raises the question of how well quantum programs perform. Benchmarking behavior is challenging since the multiple steps to synthesize an adiabatic quantum program are highly tunable. We present an adiabatic quantum programming environment called JADE that provides control over all the steps taken during program development. JADE captures the workflow needed to rigorously benchmark performance while also allowing a variety of problem types, programming techniques, and processor configurations. We have also integrated JADE with a quantum simulation engine that enables program profiling using numerical calculation. The computational engine supports plug-ins for simulation methodologies tailored to various metrics and computing resources. We present the design, integration, and deployment of JADE and discuss its use for benchmarking adiabatic quantum programs.
Adiabatic logic future trend and system level perspective
Teichmann, Philip
2012-01-01
Adiabatic logic is a potential successor for static CMOS circuit design when it comes to ultra-low-power energy consumption. Future development like the evolutionary shrinking of the minimum feature size as well as revolutionary novel transistor concepts will change the gate level savings gained by adiabatic logic. In addition, the impact of worsening degradation effects has to be considered in the design of adiabatic circuits. The impact of the technology trends on the figures of merit of adiabatic logic, energy saving potential and optimum operating frequency, are investigated, as well as degradation related issues. Adiabatic logic benefits from future devices, is not susceptible to Hot Carrier Injection, and shows less impact of Bias Temperature Instability than static CMOS circuits. Major interest also lies on the efficient generation of the applied power-clock signal. This oscillating power supply can be used to save energy in short idle times by disconnecting circuits. An efficient way to generate the p...
How detrimental is decoherence in adiabatic quantum computation?
Albash, Tameem
2015-01-01
Recent experiments with increasingly larger numbers of qubits have sparked renewed interest in adiabatic quantum computation, and in particular quantum annealing. A central question that is repeatedly asked is whether quantum features of the evolution can survive over the long time-scales used for quantum annealing relative to standard measures of the decoherence time. We reconsider the role of decoherence in adiabatic quantum computation and quantum annealing using the adiabatic quantum master equation formalism. We restrict ourselves to the weak-coupling and singular-coupling limits, which correspond to decoherence in the energy eigenbasis and in the computational basis, respectively. We demonstrate that decoherence in the instantaneous energy eigenbasis does not necessarily detrimentally affect adiabatic quantum computation, and in particular that a short single-qubit $T_2$ time need not imply adverse consequences for the success of the quantum adiabatic algorithm. We further demonstrate that boundary canc...
Power spectra in the eikonal approximation with adiabatic and non-adiabatic modes
Bernardeau, Francis; Vernizzi, Filippo
2012-01-01
We use the so-called eikonal approximation, recently introduced in the context of cosmological perturbation theory, to compute power spectra for multi-component fluids. We demonstrate that, at any given order in standard perturbation theory, multi-point power spectra do not depend on the large-scale adiabatic modes. Moreover, we employ perturbation theories to decipher how non-adiabatic modes, such as a relative velocity between two different components, damp the small-scale matter power spectrum, a mechanism recently described in the literature. In particular, we do an explicit calculation at 1-loop order of this effect. While the 1-loop result eventually breaks down, we show how the damping effect can be fully captured by the help of the eikonal approximation. A relative velocity not only induces mode damping but also creates large-scale anisotropic modulations of the matter power spectrum amplitude. We illustrate this for the Local Group environment.
Non-adiabatic molecular dynamics with complex quantum trajectories. II. The adiabatic representation
Energy Technology Data Exchange (ETDEWEB)
Zamstein, Noa; Tannor, David J. [Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100 (Israel)
2012-12-14
We present a complex quantum trajectory method for treating non-adiabatic dynamics. Each trajectory evolves classically on a single electronic surface but with complex position and momentum. The equations of motion are derived directly from the time-dependent Schroedinger equation, and the population exchange arises naturally from amplitude-transfer terms. In this paper the equations of motion are derived in the adiabatic representation to complement our work in the diabatic representation [N. Zamstein and D. J. Tannor, J. Chem. Phys. 137, 22A517 (2012)]. We apply our method to two benchmark models introduced by John Tully [J. Chem. Phys. 93, 1061 (1990)], and get very good agreement with converged quantum-mechanical calculations. Specifically, we show that decoherence (spatial separation of wavepackets on different surfaces) is already contained in the equations of motion and does not require ad hoc augmentation.
Non-adiabatic molecular dynamics with complex quantum trajectories. II. The adiabatic representation
International Nuclear Information System (INIS)
We present a complex quantum trajectory method for treating non-adiabatic dynamics. Each trajectory evolves classically on a single electronic surface but with complex position and momentum. The equations of motion are derived directly from the time-dependent Schrödinger equation, and the population exchange arises naturally from amplitude-transfer terms. In this paper the equations of motion are derived in the adiabatic representation to complement our work in the diabatic representation [N. Zamstein and D. J. Tannor, J. Chem. Phys. 137, 22A517 (2012)]. We apply our method to two benchmark models introduced by John Tully [J. Chem. Phys. 93, 1061 (1990)], and get very good agreement with converged quantum-mechanical calculations. Specifically, we show that decoherence (spatial separation of wavepackets on different surfaces) is already contained in the equations of motion and does not require ad hoc augmentation.
DEFF Research Database (Denmark)
Xenaki, Angeliki; Mosegaard, Klaus
2014-01-01
Sound source localization with sensor arrays involves the estimation of the direction-of-arrival (DOA) from a limited number of observations. Compressive sensing (CS) solves such underdetermined problems achieving sparsity, thus improved resolution, and can be solved efficiently with convex...
Energy Technology Data Exchange (ETDEWEB)
Harrington, Joe [Sertco Industries, Inc., Okemah, OK (United States); Vazquez, Daniel [Hoerbiger Service Latin America Inc., Deerfield Beach, FL (United States); Jacobs, Denis Richard [Hoerbiger do Brasil Industria de Equipamentos, Cajamar, SP (Brazil)
2012-07-01
Over time, all wells experience a natural decline in oil and gas production. In gas wells, the major problems are liquid loading and low downhole differential pressures which negatively impact total gas production. As a form of artificial lift, wellhead compressors help reduce the tubing pressure resulting in gas velocities above the critical velocity needed to surface water, oil and condensate regaining lost production and increasing recoverable reserves. Best results come from reservoirs with high porosity, high permeability, high initial flow rates, low decline rates and high total cumulative production. In oil wells, excessive annulus gas pressure tends to inhibit both oil and gas production. Wellhead compression packages can provide a cost effective solution to these problems by reducing the system pressure in the tubing or annulus, allowing for an immediate increase in production rates. Wells furthest from the gathering compressor typically benefit the most from wellhead compression due to system pressure drops. Downstream compressors also benefit from higher suction pressures reducing overall compression horsepower requirements. Special care must be taken in selecting the best equipment for these applications. The successful implementation of wellhead compression from an economical standpoint hinges on the testing, installation and operation of the equipment. Key challenges and suggested equipment features designed to combat those challenges and successful case histories throughout Latin America are discussed below.(author)
DEFF Research Database (Denmark)
Blarke, Morten
2011-01-01
recovered from flue gasses as the only low-temperature heat source, furthermore applying an intermediate cold storage allowing for non-concurrent operation of heat pump and cogeneration unit. The novel concept is subject to a detailed techno-economic comparative modelling and analysis, hich finds...
Isotropic polarization of compressible flows
Zhu, Jian-Zhou
2015-01-01
The helical absolute equilibrium of a compressible adiabatic flow presents not only the polarization between the two purely helical modes of opposite chiralities but also that between the vortical and acoustic modes, deviating from the equipartition predicted by {\\sc Kraichnan, R. H.} [1955 The Journal of the Acoustical Society of America {\\bf 27}, 438--441.] Due to the existence of the acoustic mode, even if all Fourier modes of one chiral sector in the sharpened Helmholtz decomposition [{\\sc Moses, H. E.} 1971 SIAM ~(Soc. Ind. Appl. Math.) J. Appl. Math. {\\bf 21}, 114--130] are thoroughly truncated, negative temperature and the corresponding large-scale concentration of vortical modes are not allowed, unlike the incompressible case.
International Nuclear Information System (INIS)
The behavior of strong magnetosonic waves propagating perpendicular to a static field B0 is investigated within the frequency range ω/sub c/i0 results; the electrons exhibit only poor heating associated with their adiabatic compression. The dynamics of both particle species, the consequences of the wave--particle energy transfer and the particle viscosities, are studied in detail. Competitive and self-consistent effects such as space-charge effects, wave overtaking, ion trapping, and wave damping are investigated and compared with previous models; the mechanisms by which these various phenomena interact on each other are analyzed. Characteristics of nonstochastic and stochastic ion heating are also discussed. Our computations show that if sufficient intensity is reached, one is not constrained to use lower-hybrid waves or cyclotron harmonic waves to heat a plasma efficiently and that any frequency below ω/sub lh/ can be used
Stolzmann, W
2000-01-01
Starting from the Helmholtz free energy we calculate analytically first- and second-order derivatives, as internal energy and specific heats, for the ideal system and the exchange and correlation interactions covering a broad range of degeneracy and relativity. The complex physics of Coulomb interactions is expressed by Pade Approximants, which reflect the actual state of our knowledge with high accuracy. We assume complete ionization and provide a base system of thermodynamical functions from which any other thermodynamical quantities can be calculated. We chose for the base system the free energy, the pressure, the internal energy, the isothermal compressibility (or density exponent), the coefficient of strain (or temperature exponent), and the isochoric specific heat. By means of the latter potentials entropy, isobaric specific heat and adiabatic temperature gradient can be determined. We give comparisons with quantities which are composed by numerical second-order derivatives of the free energy and show t...
Energy Technology Data Exchange (ETDEWEB)
Van der Pal, M.; De Boer, R.; Wemmers, A.K.; Smeding, S.F.; Veldhuis, J.B.J.; Lycklama a Nijeholt, J.A.
2013-10-15
Thermally driven sorption systems can provide significant energy savings, especially in industrial applications. The driving temperature for operation of such systems limits the operating window and can be a barrier for market-introduction. By adding a compressor, the sorption cycle can be run using lower waste heat temperatures. ECN has recently started the development of such a hybrid heat pump. The final goal is to develop a hybrid heat pump for upgrading lower (<100C) temperature industrial waste heat to above pinch temperatures. The paper presents the first measurements and model calculations of a hybrid heat pump system using a water-silica gel system combined with a Roots type compressor. From the measurements can be seen that the effect of the compressor is dependent on where in the cycle it is placed. When placed between the evaporator and the sorption reactor, it has a considerable larger effect compared to the compressor placed between the sorption reactor and the condenser. The latter hardly improves the performance compared to purely heat-driven operation. This shows the importance of studying the interaction between all components of the system. The model, which shows reasonable correlation with the measurements, could proof to be a valuable tool to determine the optimal hybrid heat pump configuration.
Ealker, David H.; Deming, Glenn
1991-01-01
Heat pump collects heat from water circulating in heat-rejection loop, raises temperature of collected heat, and transfers collected heat to water in separate pipe. Includes sealed motor/compressor with cooling coils, evaporator, and condenser, all mounted in outer housing. Gradients of temperature in evaporator and condenser increase heat-transfer efficiency of vapor-compression cycle. Intended to recover relatively-low-temperature waste heat and use it to make hot water.
Weike, Pang; Wenju, Lin; Qilin, Pan; Wenye, Lin; Qunte, Dai; Luwei, Yang; Zhentao, Zhang
2014-01-01
In this paper, a set of heat pump (called as Mechanical Vapor Recompression, MVR) propelled by a centrifugal fan is tested and it shows some special characteristic when it works together with a falling film evaporator. Firstly, an analysis of the fan's suction and discharge parameters at stable state, such as its pressure and temperature, indicates that a phenomenon of wet compression is probably to appear during vapor compression. As a result, superheat after saturated vapor is compressed is eliminated, which reduces discharge temperature of the system. It is because drops boil away and absorb the super heat into their latent heat during vapor compression. Meanwhile, drops in the suction vapor add to the compressed vapor, which increase the given heat of the MVR heat pump. Next, assistant electric heat could adjust and keep steady of the operating pressure and temperature of an MVR heat pump. With the evaporation temperature up to be high, heat balance is broken and supplement heat needs to increase. Thirdly, the performance of an MVR heat pump is affect by the balance of falling film and evaporation that has an effect on heat transfer. Then, two parameters standing for the performance are measured as it runs in practical condition. The two important parameters are consumptive electricity power and productive water capacity. According to theoretical work in ideal condition by calculation and fan's input power by measure as running, adiabatic efficiency (ηad) of a centrifugal fan is calculated when it is applied in a heat pump of MVR. Following, based on ηad, practical SMER and COP of an MVR heat pump are discovered to be correlative with it. Finally, in dependence on productive water in theory and in practice, displacement efficiency (ηv) of centrifugal fans is obtained when compressing vapor, and so provide some references of matching a fan for an MVR heat pump. On the other hand, it is helpful to research and develop MVR heat pumps, and also to check
Yang, Xiaoqiu; Lin, Weiren; Tadai, Osamu; Zeng, Xin; Xu, Ziying; Shi, Xiaobin; Yu, Chuanhai
2016-04-01
Thermal properties of rocks under high pressure are very important for us to understand the thermal structure and state of earth. Basing on the classical thermo-elastic theory, we can know that the temperature of an elastic substance will change when it is compressed or stretched under adiabatic condition. Our measurement results show that the adiabatic stress derivative of temperature (dT/dP) of rocks ranges from 1 to 6 mK/MPa. But the result of silicone oil is up to about 140 mK/MPa. So, we developed a measurement method and system of the thermal properties of rocks under high pressure. In the hydrostatic compression system, the confining pressure can rapidly increase to high pressure within 1~2 s by controlling the value. By monitoring the temperature changes in center and on surface of rock sample during the rapidly loading process, the thermal properties, including thermal conductivity, thermal diffusivity and volumetric heat capacity, can be resolved by our finite element numerical inversion method. We measured several representative rocks from Longmenshan Fault Zone and Chelungpu Fault Zone (TCDP Hole-A), such as sandstone, siltstone, limestone, granite, basalt, tuff and so on. The results indicate that this method and system is suitable for thermal properties measurement under high pressure even though there is without heat source.
DiPirro, M. J.; Shirron, P. J.
2014-01-01
Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.
Experimental implementation of an adiabatic quantum optimization algorithm
Steffen, M; Hogg, T; Breyta, G; Chuang, I; Steffen, Matthias; Dam, Wim van; Hogg, Tad; Breyta, Greg; Chuang, Isaac
2003-01-01
We report the realization of a nuclear magnetic resonance computer with three quantum bits that simulates an adiabatic quantum optimization algorithm. Adiabatic quantum algorithms offer new insight into how quantum resources can be used to solve hard problems. This experiment uses a particularly well suited three quantum bit molecule and was made possible by introducing a technique that encodes general instances of the given optimization problem into an easily applicable Hamiltonian. Our results indicate an optimal run time of the adiabatic algorithm that agrees well with the prediction of a simple decoherence model.
A note on the geometric phase in adiabatic approximation
Tong, D M; Kwek, L C; Oh, C H
2004-01-01
It is widely held that the Berry phase of a quantum system is the geometric phase in adiabatic approximation. However, Pati and Rajagopal recently claimed that the Berry phase vanishes under strict adiabatic evolution. In this note, we reexamine and address this issue. In particular, we show that the use of the adiabatic theorem does not lead to this inconsistency. We also examine the difference between the Berry phase and the exact geometric phase. Here we find that the Berry phase may differ appreciably from the exact geometric phase if the evolution time is large enough.
Approximability of optimization problems through adiabatic quantum computation
Cruz-Santos, William
2014-01-01
The adiabatic quantum computation (AQC) is based on the adiabatic theorem to approximate solutions of the Schrödinger equation. The design of an AQC algorithm involves the construction of a Hamiltonian that describes the behavior of the quantum system. This Hamiltonian is expressed as a linear interpolation of an initial Hamiltonian whose ground state is easy to compute, and a final Hamiltonian whose ground state corresponds to the solution of a given combinatorial optimization problem. The adiabatic theorem asserts that if the time evolution of a quantum system described by a Hamiltonian is l
Adiabatic Pair Creation in Heavy Ion and Laser Fields
Pickl, P; Pickl, Peter; Duerr, Detlef
2006-01-01
The planned generation of lasers and heavy ion colliders renews the hope to see electron-positron pair creation in strong classical fields (so called spontaneous pair creation). This adiabatic relativistic effect has however not been described in a unified manner. We discuss here the theory of adiabatic pair creation yielding the momentum distribution of scattered pairs in overcritical fields. Our conclusion about the possibility of adiabatic pair creation is much more positive than earlier predictions for laser fields and most importantly gives priority to optical before X-ray lasers.
Constraints on the Adiabatic Temperature Change in Magnetocaloric Materials
DEFF Research Database (Denmark)
Nielsen, Kaspar Kirstein; Bahl, Christian Robert Haffenden; Smith, Anders
2010-01-01
The thermodynamics of the magnetocaloric effect implies constraints on the allowed variation in the adiabatic temperature change for a magnetocaloric material. An inequality for the derivative of the adiabatic temperature change with respect to temperature is derived for both first- and second......-order materials. For materials with a continuous adiabatic temperature change as a function of temperature, this inequality is shown to hold for all temperatures. However, discontinuous materials may violate the inequality. We compare our results with measured results in the literature and discuss...
Adiabatic control of atomic dressed states for transport and sensing
Cooper, N. R.; Rey, A. M.
2015-08-01
We describe forms of adiabatic transport that arise for dressed-state atoms in optical lattices. Focusing on the limit of weak tunnel-coupling between nearest-neighbor lattice sites, we explain how adiabatic variation of optical dressing allows control of atomic motion between lattice sites: allowing adiabatic particle transport in a direction that depends on the internal state, and force measurements via spectroscopic preparation and readout. For uniformly filled bands these systems display topologically quantized particle transport. An implementation of the dressing scheme using optical transitions in alkaline-earth atoms is discussed as well as its favorable features for precise force sensing.
Directory of Open Access Journals (Sweden)
P. Meena
2008-01-01
Full Text Available This research was to study the comparisons of heat transfer performance of closed-looped oscillating heat pipe and closed-looped oscillating heat pipe with check valves heat exchangers with R134a, Ethanol and water were used as the working fluids. A set of heat pipe heat exchanger (CLOHP and CLOHP/CV were made of copper tubes in combination of following dimension: 2.03 mm inside diameter: 40 turns, with 20, 10 and 20 cm for evaporator, adiabatic and condenser sections lengths. The working fluid was filled in the tube at the filling ratio of 50%. The evaporator section was given heat by heater while the condenser section was cooled by air. The adiabatic section was properly insulated. In the test operation, it could be concluded as follows. It indicated that the heat transfer performance of closed-looped oscillating heat pipe with check valves heat exchanger better than closed-looped oscillating heat exchanger.
A heat transient model for the thermal behavior prediction of stratospheric airships
International Nuclear Information System (INIS)
The gas temperature of a stratospheric airship plays an important role in its flight dynamics. A multi-nodes heat transient model is proposed and evaluated by the theoretical solutions of the adiabatic processes and the high altitude flight test data. A thermodynamic analysis code for stratospheric airships (TACSA) is developed to investigate the ascent subcooling induced by the thermodynamic expansion and the descent superheating induced by the thermodynamic compression. The simulation results show that the airship volume, vertical speed and the solar radiation have evident influence on the ascent subcooling descent superheating effects. - Highlights: • A multi-nodes heat transient model for stratospheric airships is proposed. • The thermal behaviors of the ascent and descent processes are predicted. • The volume, vertical speed and solar radiation have significant influence
Plasma Compression by a Magnetic Field in a Toroidal-Type Device
International Nuclear Information System (INIS)
The Tuman device, a racetrack, was built to study the adiabatic compression of a plasma column by an external magnetic field increasing with time, and was designed to carry out two-stage heating of the plasma. Magnetic compression is preceded by ohmic heating of the plasma under conditions analogous to those for the operation of Tokamak. During ohmic heating the longitudinal magnetic field is essentially non-uniform. In the curved toroidal sections the maximum quasi-stationary magnetic field is approximately 40 kOe, and in the straight parts 1 to 2 kOe. The glass discharge chamber, is a magnetic force tube, that is its cross section in the curved sections is 1/20th the cross section in the straight sections. The plasma must fill the force tube, whose dimensions are set by a diaphragm in the middle of the straight section and by the ratio of field intensities in the straight and curved sections. With our column configuration considerably more power can be introduced into the plasma than in a uniform torus. The plasma volume is approximately 15 1 when the plasma column is 250 cm long. Compression must be carried out by increasing the longitudinal magnetic field in the straight sections to 30 kOe. The field build-up time may vary from 30 to 250 μs. The plasma must be compressed in the wide, straight sections to approximately the same cross-section as in the curved sections. Compression reduces the volume of plasma by a factor of 10 to 20. All the tests were carried out with hydrogen at pressures from 1 x 10-3 to 5 x 10-2 Torr. The toroidal discharge was excited by a transformer. The duration of ohmic heating was 300 μs. The current in the plasma did not normally exceed 1 to 2 kA. With a quasi-stationary magnetic field of 1 to 2 kOe in the curved sections, plasma is obtained with a conductivity of (1 to 2) x 1014esu. Measurements of the diamagnetic moment of the plasma and microwave measurements showed that.when the magnetic field in the toroidal sections was
Graph isomorphism and adiabatic quantum computing
Gaitan, Frank; Clark, Lane
2014-03-01
In the Graph Isomorphism (GI) problem two N-vertex graphs G and G' are given and the task is to determine whether there exists a permutation of the vertices of G that preserves adjacency and maps G --> G'. If yes (no), then G and G' are said to be isomorphic (non-isomorphic). The GI problem is an important problem in computer science and is thought to be of comparable difficulty to integer factorization. We present a quantum algorithm that solves arbitrary instances of GI, and which provides a novel approach to determining all automorphisms of a graph. The algorithm converts a GI instance to a combinatorial optimization problem that can be solved using adiabatic quantum evolution. Numerical simulation of the algorithm's quantum dynamics shows that it correctly distinguishes non-isomorphic graphs; recognizes isomorphic graphs; and finds the automorphism group of a graph. We also discuss the algorithm's experimental implementation and show how it can be leveraged to solve arbitrary instances of the NP-Complete Sub-Graph Isomorphism problem.
Adiabatic fission barriers in superheavy nuclei
Jachimowicz, P; Skalski, J
2016-01-01
Using the microscopic-macroscopic model based on the deformed Woods-Saxon single-particle potential and the Yukawa-plus-exponential macroscopic energy we calculated static fission barriers $B_{f}$ for 1305 heavy and superheavy nuclei $98\\leq Z \\leq 126$, including even - even, odd - even, even - odd and odd - odd systems. For odd and odd-odd nuclei, adiabatic potential energy surfaces were calculated by a minimization over configurations with one blocked neutron or/and proton on a level from the 10-th below to the 10-th above the Fermi level. The parameters of the model that have been fixed previously by a fit to masses of even-even heavy nuclei were kept unchanged. A search for saddle points has been performed by the "Imaginary Water Flow" method on a basic five-dimensional deformation grid, including triaxiality. Two auxiliary grids were used for checking the effects of the mass asymmetry and hexadecapole non-axiallity. The ground states were found by energy minimization over configurations and deformations...
Topological States and Adiabatic Pumping in Quasicrystals
Kraus, Yaakov; Lahini, Yoav; Ringel, Zohar; Verbin, Mor; Zilberberg, Oded
2012-02-01
We find a connection between quasicrystals and topological matter, namely that quasicrystals exhibit non-trivial topological phases attributed to dimensions higher than their own [1]. Quasicrystals are materials which are neither ordered nor disordered, i.e. they exhibit only long-range order [2]. This long-range order is usually expressed as a projection from a higher dimensional ordered system. Recently, the unrelated discovery of Topological Insulators [3] defined a new type of materials classified by their topology. We show theoretically and experimentally using photonic lattices, that one-dimensional quasicrystals exhibit topologically-protected boundary states equivalent to the edge states of the two-dimensional Integer Quantum Hall Effect. We harness this property to adiabatically pump light across the quasicrystal, and generalize our results to higher dimensional systems. Hence, quasicrystals offer a new platform for the study of topological phases while their topology may better explain their surface properties.[4pt] [1] Y. E. Kraus, Y. Lahini, Z. Ringel, M. Verbin, and O. Zilberberg, arXiv:1109.5983 (2011).[0pt] [2] C. Janot, Quasicrystals (Clarendon, Oxford, 1994), 2nd ed.[0pt] [3] M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 3045 (2010).
Institute of Scientific and Technical Information of China (English)
张辉; 陈容; 黄旭东; 陈江华
2011-01-01
研究2026铝合金在温度为300-450℃和应变速率为0.01-10 s-1的变形条件与固溶时效热处理后微观组织之间的关系.结果表明:热处理后的再结晶和析出特性与热变形时的温度补偿应变速率Z有关.在低Z条件下,热处理后会形成少量细小的再结晶晶粒,热变形过程产生的高角度亚晶粒和粗大析出物被保留下来;高Z条件下,热处理后会产生大量细小等轴晶再结晶晶粒,热变形过程产生的高密度晶胞和相对细小的动态析出物被热处理后完整的亚晶粒和相对粗化的析出物所替代.热处理后的平均再结晶晶粒尺寸随着Z值的增加而减小.建立两者的定量关系式.%2026 aluminum alloy was compressed in a temperature range of 300-450 ℃ and strain rate range of 0.01-10 s-1. The correlation between compression conditions and microstructural evolution after solution and aging heat treatment was investigated. It is found that the recrystallization and precipitation behavior after heat treatment are associated with the temperature compensated strain rate Z value during hot deformation. Under low Z parameter condition, a small quantity of fine recrystallized grains are formed, and the well formed subgrains with clean high-angle boundaries and coarse precipitates seem to be remained during heat treatment. Under high Z parameter condition, a large number of fine equiaxed recrystallized grains are produced, and a high dislocation density with poorly developed cellularity and considerable fine dynamic precipitates are replaced by the well formed subgrains and relatively coarse precipitates after heat treatment. The average recrystallized grain size after heat treatment decreases with increasing Z value and a quantitative relation between the average grain size and the Z value is obtained.
Stimulated Raman Adiabatic Passage for Improved Performance of a Cold Atom Electron and Ion Source
Sparkes, B M; Taylor, R J; Spiers, R W; McCulloch, A J; Scholten, R E
2016-01-01
We experimentally implement high-efficiency coherent excitation to a Rydberg state using stimulated Raman adiabatic passage in a cold atom electron and ion source, leading to a peak efficiency of 85%, a 1.7 times improvement in excitation probability relative to incoherent pulsed-laser excitation. Using streak measurements and pulsed electric field ionization of the Rydberg atoms we demonstrate electron bunches with duration of 250 ps. High-efficiency excitation will increase source brightness, crucial for ultrafast electron diffraction experiments, while using coherent excitation to high-lying Rydberg states could allow for the reduction of internal bunch heating and the creation of a high-speed single ion source.
Adiabatic rotation, quantum search, and preparation of superposition states
Siu, M. Stewart
2007-06-01
We introduce the idea of using adiabatic rotation to generate superpositions of a large class of quantum states. For quantum computing this is an interesting alternative to the well-studied “straight line” adiabatic evolution. In ways that complement recent results, we show how to efficiently prepare three types of states: Kitaev’s toric code state, the cluster state of the measurement-based computation model, and the history state used in the adiabatic simulation of a quantum circuit. We also show that the method, when adapted for quantum search, provides quadratic speedup as other optimal methods do with the advantages that the problem Hamiltonian is time independent and that the energy gap above the ground state is strictly nondecreasing with time. Likewise the method can be used for optimization as an alternative to the standard adiabatic algorithm.
Application of adiabatic calorimetry to metal systems. Final report
International Nuclear Information System (INIS)
Research on the application of adiabatic calorimetry to metal systems is described. Investigations into formation of pearlite in steels, ferromagnetic effects, cold working and annealing, solid solution alloys, pure solid metals, and pure liquid metals, are briefly described
Magnesium Diboride Superconducting Coils for Adiabatic Demagnetization Refrigerators (ADR's) Project
National Aeronautics and Space Administration — For Adiabatic Demagnetization Refrigerators(ADR's) for space it is desirable to have very light weight, small diameter, high current density superconducting wires...
AN ADIABATIC APPROACH FOR LOW POWER FULL ADDER DESIGN
Directory of Open Access Journals (Sweden)
Prof. Dinesh Chandra
2011-09-01
Full Text Available Over the past decade, several adiabatic logic styles have been reported. This paper deals with the design of a 1-bit full adder using several adiabatic logic styles, which are derived from static CMOS logic, without a large change. The full adders are designed using 180nm technology parameters provided by predictive technology and simulated using HSPICE. The full adders designed are compared in terms of average power consumption with different values of load capacitance, temperature and input frequency. The different designs of full adder are also compared on the basis of propagation delay exhibit by them. It is found that, full adders designed with adiabatic logic styles tends to consume very low power in comparison to full adder designed with static CMOS logic. Under certain operating conditions, one of adiabatic designs of full adder achieves upto 74% power saving in comparison to the full adder designedwith static CMOS logic.
Heat pumps in industry. Pt. 2: Applications
Energy Technology Data Exchange (ETDEWEB)
Lazzarin, R.M. [Padova Univ., Vicenza (Italy). Ist. di Ingegneria Gestionale
1995-04-01
A selection of applications of heat pumps in industry is described, reporting plant lay-outs and performances. The selection includes compression heat pumps at different temperatures, vapour recompression systems, absorption heat pumps and heat transformers. (author)
Adiabatic instability in coupled dark energy-dark matter models
Bean, Rachel; Flanagan, Eanna E.; Trodden, Mark
2007-01-01
We consider theories in which there exists a nontrivial coupling between the dark matter sector and the sector responsible for the acceleration of the universe. Such theories can possess an adiabatic regime in which the quintessence field always sits at the minimum of its effective potential, which is set by the local dark matter density. We show that if the coupling strength is much larger than gravitational, then the adiabatic regime is always subject to an instability. The instability, whi...
Hybrid adiabatic potentials in the QCD string model
Kalashnikova, Yu S; Kalashnikova, Yu.S.
2003-01-01
The short- and intermediate-distance behaviour of the hybrid adiabatic potentials is calculated in the framework of the QCD string model. The calculations are performed with the inclusion of Coulomb force. Spin-dependent force and the so-called string correction term are treated as perturbation at the leading potential-type regime. Reasonably good agreement with lattice measurements takes place for adiabatic curves excited with magnetic components of field strength correlators.
Adiabatic Quantum Programming: Minor Embedding With Hard Faults
Klymko, Christine; Sullivan, Blair D.; Humble, Travis S.
2012-01-01
Adiabatic quantum programming defines the time-dependent mapping of a quantum algorithm into an underlying hardware or logical fabric. An essential step is embedding problem-specific information into the quantum logical fabric. We present algorithms for embedding arbitrary instances of the adiabatic quantum optimization algorithm into a square lattice of specialized unit cells. These methods extend with fabric growth while scaling linearly in time and quadratically in footprint. We also provi...
Adiabatic CMB perturbations in pre-big bang string cosmology
Enqvist, Kari; Enqvist, Kari; Sloth, Martin S.
2002-01-01
We consider the pre-big bang scenario with a massive axion field which starts to dominate energy density when oscillating in an instanton-induced potential and subsequently reheats the universe as it decays into photons, thus creating adiabatic CMB perturbations. We find that the fluctuations in the axion field can give rise to a nearly flat spectrum of adiabatic perturbations with a spectral tilt $\\Delta n$ in the range $-0.1 \\lesssim \\Delta n \\lesssim 0.3$.
Preparation of Entangled States of Three Particles by Adiabatic Passage
Institute of Scientific and Technical Information of China (English)
郭建友
2002-01-01
We propose a novel technique for the creation of entangled states of three particles, based upon an adiabatic passage induced by a suitably crafted time-dependent external field. We derive the corresponding adiabatic and bare conditions for the preparation of entangled states. We obtain the time evolutions of the energy of the system and the populations involving the initial state and target entangled state.
Dependence of adiabatic population transfer on pulse profile
Indian Academy of Sciences (India)
S Dasgupta; T kushwaha; D Goswami
2006-06-01
Control of population transfer by rapid adiabatic passage has been an established technique wherein the exact amplitude profile of the shaped pulse is considered to be insignificant. We study the effect of ultrafast shaped pulses for two-level systems, by density-matrix approach. However, we find that adiabaticity depends simultaneously on pulse profile as well as the frequency modulation under non-resonant conditions.
Adiabatic invariant value variation under shortwave band subcritical conditions
Svistunov, K. V.; Tinin, M. V.
1985-04-01
The possibility of significant variations of the adiabatic invariant is examined for the propagation of radio waves in an irregular Earth-ionosphere waveguide with a parabolic dependence of permittivity on height. Numerical and analytical results indicate that nonexponential deviations of the adiabatic invariant can occur not only when the characteristic size of horizontal irregularity decreases (e.g., during resonant beam excitation) but also in quasi-critical conditions and for smoothly irregular waveguides.
Institute of Scientific and Technical Information of China (English)
LUO Shao-Kai
2007-01-01
For a Lagrangian system with the action of small disturbance, the Lie symmetrical perturbation and a new type of non-Noether adiabatic invariant are presented in general infinitesimal transformation groups. On the basis of the invariance of disturbed Lagrangian systems under general infinitesimal transformations, the determining equations of Lie symmetries of the system are constructed. Based on the definition of higher-order adiabatic invariants of a mechanical system, a new type of adiabatic invariant, i.e. generalized Lutzky adiabatic invariants, of a disturbed Lagrangian system are obtained by investigating the perturbation of Lie symmetries for a Lagrangian system with the action of small disturbance. Finally, an example is given to illustrate the application of the method and results.
Microstructure of adiabatic shear bands in Ti6Al4V
International Nuclear Information System (INIS)
Microstructural deformation mechanisms in adiabatic shear bands in Ti6Al4V are studied using traditional TEM and selected area diffraction, and more advanced microstructural characterisation techniques such as energy dispersive X-ray spectroscopy, high angle annular dark field STEM and conical dark field TEM. The shear bands under investigation are induced in Ti6Al4V samples by high strain rate compression of cylindrical and hat-shaped specimens in a split Hopkinson pressure bar setup. Samples from experiments interrupted at different levels of deformation are used to study the evolution of the microstructure in and nearby the shear bands. From the early stages of adiabatic shear band formation, TEM revealed strongly elongated equiaxed grains in the shear band. These band-like grains become narrower towards the centre of the band and start to fraction even further along their elongated direction to finally result in a nano-crystalline region in the core. In fully developed shear bands, twins and a needle-like martensite morphology are observed near the shear band. - Highlights: ► CDF can resolve the nanostructure of an ASB. ► Nanometre-sized grains well below 100 nm are present in the shear band. ► Highly fractioned regions inside ASB contain both α and β phases. ► Strong deformation yields α twins and martensite morphology. ► The microstructure of the ASB in both samples is similar.
Efficiency of Compressed Air Energy Storage
DEFF Research Database (Denmark)
Elmegaard, Brian; Brix, Wiebke
2011-01-01
were reversible have a storage efficiency of 100%. However, due to the specific capacity of the storage and the construction materials the air is cooled during and after compression in practice, making the CAES process diabatic. The cooling involves exergy losses and thus lowers the efficiency...... of the storage significantly. The efficiency of CAES as an electricity storage may be defined in several ways, we discuss these and find that the exergetic efficiency of compression, storage and production together determine the efficiency of CAES. In the paper we find that the efficiency of the practical CAES...... electricity storage is 25-45% and thus has a quite low efficiency, which is close to the efficiency of the simple diabatic CAES-process. Adiabatic CAES would reach significantly higher storage efficiency about 70-80%....
Dynamical fluctuations in classical adiabatic processes: General description and their implications
Zhang, Qi; Gong, Jiangbin; Oh, C. H.
2010-01-01
Dynamical fluctuations in classical adiabatic processes are not considered by the conventional classical adiabatic theorem. In this work a general result is derived to describe the intrinsic dynamical fluctuations in classical adiabatic processes. Interesting implications of our general result are discussed via two subtopics, namely, an intriguing adiabatic geometric phase in a dynamical model with an adiabatically moving fixed-point solution, and the possible "pollution" to Hannay's angle or...
Gonen, S.
2014-01-01
The present study was carried out with 46 teacher candidates taking the course of "Thermodynamics" in the Department of Physics Teaching. The purpose of the study was to determine the difficulties that teacher candidates experienced in explaining the heat, work and internal energy relationships in the processes of adiabatic compression…
Lee, Joon Sang
The compressible filtered Navier-Stokes equations were solved using a second order accurate finite volume method with low Mach number preconditioning. A dynamic subgrid-scale stress model accounted for the subgrid-scale turbulence. The study focused on the effects of buoyancy and rotation on the structure of turbulence and transport processes including heat transfer. Several different physical arrangements were studied as outlined below. The effects of buoyancy were first studied in a vertical channel using large eddy simulation (LES). The walls were maintained at constant temperatures, one heated and the other cooled. Results showed that aiding and opposing buoyancy forces emerge near the heated and cooled walls, respectively. In the aiding flow, the turbulent intensities and heat transfer were suppressed at large values of Grashof number. In the opposing flow, however, turbulence was enhanced with increased velocity fluctuations. Another buoyancy study considered turbulent flow in a vertically oriented annulus. Isoflux wall boundary conditions with low and high heating were imposed on the inner wall while the outer wall was adiabatic. The results showed that the strong heating and buoyancy force caused distortions of the flow structure resulting in reduction of turbulent intensities, shear stress, and turbulent heat flux, particularly near the heated wall. Flow in an annular pipe with and without an outer wall rotation about its axis was first investigated at moderate Reynolds numbers. When the outer pipe wall was rotated, a significant reduction of turbulent kinetic energy was realized near the rotating wall. Secondly, a large eddy simulation has been performed to investigate the effect of swirl on the heat and momentum transfer in an annular pipe flow with a rotating inner wall. The simulations indicated that the Nusselt number and the wall friction coefficient increased with increasing rotation speed of the wall. It was also observed that the axial velocity
Dixon, G. V.; Barringer, S. R.; Gray, C. E.; Leatherman, A. D.
1975-01-01
Computer programs and resulting tabulations are presented of pipeline length-to-diameter ratios as a function of Mach number and pressure ratios for compressible flow. The tabulations are applicable to air, nitrogen, oxygen, and hydrogen for compressible isothermal flow with friction and compressible adiabatic flow with friction. Also included are equations for the determination of weight flow. The tabulations presented cover a wider range of Mach numbers for choked, adiabatic flow than available from commonly used engineering literature. Additional information presented, but which is not available from this literature, is unchoked, adiabatic flow over a wide range of Mach numbers, and choked and unchoked, isothermal flow for a wide range of Mach numbers.
An important feature of air heat pump cycle: Heating capacity in line with heating load
International Nuclear Information System (INIS)
In the conventional vapor-compression heat pumps, the heating capacity and the heating load usually vary in opposite directions, which results in a mismatch of the heating capacity and the heating load at off-design conditions. Air (reversed Brayton) cycle is a potential substitute for the conventional vapor-compression cycles. This paper proved that in theory the air heat pump cycle can make the heating capacity in line with the heating load at a stable level of heating COP (coefficient of performance). A thermodynamic model for the air heat pump cycle with practical compressor and expander was developed. The optimal heating COP and the corresponding pressure ratio were derived from the model. Then the cycle performance was analytically expressed under the optimal COP conditions. The heating capacity under different operating conditions was found in line with the heating load. Comparisons between the air heat pump cycle and two typical vapor-compression heat pump cycles were numerically done for further verification. It also turned out that the energy efficiency of air heat pump is comparable to the transcritical CO2 heat pump, particularly at large temperature difference. - Highlights: • We developed a thermodynamic model for air heat pump cycle. • The optimal COP (coefficient of performance) was derived and the corresponding cycle performance was analyzed. • Comparison of air heat pump cycle and vapor-compression cycles was numerically done. • We proved air heat pump cycle can make heating capacity in line with heating load
CO2双级压缩制冷热泵循环性能研究%Performance Analysis of CO2 Two-stage Compression Refrigeration Heat Pump Cycle
Institute of Scientific and Technical Information of China (English)
刘雄; 姜乔乔; 郭浩波
2011-01-01
This paper proposed a two-stage compression refrigeration heat pump cycle. It can not only recycle waste heat generated by refrigeration, but also supply cooling and domestic hot water at the same time according to the users need. Using actual cases, they are analyzed theoretically that the refrigerant mass flow rate, environment temperature, hot water temperature, high pressure compressor's exhaust pressure have influence on the new cycle's properties. In addition, the effect factors of the characteristic temperature and high pressure compressors optimum exhaust pressure are discussed.%提出了一种CO2双级压缩制冷热泵循环,它能够实现冷热量的同时独立调节；并通过实际案例,理论分析了不同制冷剂质量流量系数、不同环境温度、热水温度以及高压压缩机排气压力下,新循环的性能,考察了特征温度和最佳排气压力的影响因素.
Study on Jet-Compression Hybrid Refrigeration Cycle Driven by Heat and Power%热-电驱动喷射压缩复合制冷循环特性研究
Institute of Scientific and Technical Information of China (English)
王林; 谈莹莹; 梁坤峰; 安方涛; 陈宁
2014-01-01
Autocascade refrigeration can achieve lower refrigeration temperature easily,but it totally consumes high grade energy and its COP is low.Jet refrigeration can achieve the refrigeration effect by utilizing low grade heat sources.However,its refrigeration temperature is high.In order to utilize low grade heat to the domain of cryogenic freezing,jet/compression hybrid refrigeration cycle with mixed refrigerants driven by low grade heat and power was presented.The new cycle contributes to improving the efficiency of refrigeration significantly and achieving lower refrigeration temperature.On a basis of its mathematical model,the influences of compression ratio of the ejector and compressor on mechanical and thermal coefficient of performance(COPme/COPth) were analyzed.The results indicate that refrigeration efficiency of the hybrid refrigeration cycle is much higher than that of the traditional autocascade refrigeration cycle.%自复叠制冷循环具有获得制冷温度低优点,但其完全消耗的是高品位电能或机械能;喷射制冷具有利用低品位低温热源(60～100℃)制取冷量、且制冷温度较高时制冷效率高等优点,但难以获得较低制冷温度.因此,为了实现低品位热在低温冷冻领域高效利用并节省高品位电能,本文提出一种由低品位低温热源与电能联合驱动的混合工质喷射/压缩复合制冷循环.建立组成新循环各部件热力学数学模型,分析喷射器压缩比和压缩机压缩比对复合式制冷循环的热性能系数和机械性能系数影响,并与传统的自复叠制冷循环特性进行比较分析.研究表明,低品位热源与电能联合驱动喷射/压缩复合制冷循环较传统自复叠制冷循环可显著提高制冷效率并获得更低制冷温度.
Global weak solution and large-time behavior for the compressible flow of liquid crystals
Wang, Dehua
2011-01-01
The three-dimensional equations for the compressible flow of liquid crystals are considered. An initial-boundary value problem is studied in a bounded domain with large data. The existence and large-time behavior of a global weak solution are established through a three-level approximation, energy estimates, and weak convergence for the adiabatic exponent $\\gamma>\\frac32$.
Institute of Scientific and Technical Information of China (English)
王洁瑛; 赵广杰; 中野隆人
2001-01-01
In this study the brightness, chromatism and infra red spectra ofcompressed China fir wood during heat treatment in air or heat treatment in vacuum are studied. The water-saturated and boiled specimens of China fir （Cunninghamia lanceolata） are hot pressed with the average compression rate of 50%. Then they are heat treated in a common oven or in a vacuum oven, with the temperatures of treatment of 140，160，180，200，220℃, respectively. Then the brightness, chromatism, infra red spectra of the specimens are measured and discussed. In addition, some relationships between brightness, chromatism and recovery, weight loss and anti-swelling efficiency are deduced and discussed. The results are: (1) The brightness of the specimens will decrease and the chromatism will increase with the prolongation of time of heat treatment. Compared to heat treatment in vacuum, the specimens have less brightness and more chromatism after being heat treated in air, under the conditions of same temperature and time of heat treatment. (2) As far as the relationships between brightness, chromatism and recovery are concerned, there is little difference between heat treatment in air and heat treatment in vacuum. The fixation degree of compression set is closely related to the change degree of color. (3) As far as the relationships between brightness, chromatism and weight loss, anti-swelling efficiency are concerned, the more the weight loss or anti-swelling efficiency is, the less the brightness is, or the more the chromatism is. (4) The infra red spectra of specimens show that there are evident changes of waves at the wavelength of 1743, 1660 and 1605cm-1 which are attributed to the change of C=O in wood. So it is clear that at least hemicellulose, even lignin in wood cell chemically changes during heat treatment of compressed wood of China fir.%为了探讨热处理过程中杉木压缩木材的材色变化规律，以及材色和木材化学主成分变化之间的关系，该
Physics on the adiabatically changed Finslerian manifold and cosmology
Lipovka, Anton A
2016-01-01
In present paper we confirm our previous result [4] that Planck constant is adiabatic invariant of electromagnetic field propagating on the adiabatically changed Finslerian manifold. Direct calculation from cosmological parameters gives value h=6x10(-27) (erg s). We also confirm that Planck constant (and hence other fundamental constants which depend on h) is varied on time due to changing of geometry. As an example the variation of the fine structure constant is calculated. Its relative variation ((da/dt)/a) consist 1.0x10(-18) (1/s). We show that on the Finsler manifold characterized by adiabatically changed geometry, classical free electromagnetic field is quantized geometrically, from the properties of the manifold in such manner that adiabatic invariant of field is ET=6x10(-27)=h. Electrodynamic equations on the Finslerian manifold are suggested. It is stressed that quantization naturally appears from these equations and is provoked by adiabatically changed geometry of manifold. We consider in details tw...
Global adiabaticity and non-Gaussianity consistency condition
Romano, Antonio Enea; Sasaki, Misao
2016-01-01
In the context of single-field inflation, the conservation of the curvature perturbation on comoving slices, $R_c$, on super-horizon scales is one of the assumptions necessary to derive the consistency condition between the squeezed limit of the bispectrum and the spectrum of the primordial curvature perturbation. However, the conservation of $R_c$ holds only after the perturbation has reached the adiabatic limit where the constant mode of $R_c$ dominates over the other (usually decaying) mode. In this case, the non-adiabatic pressure perturbation defined in the thermodynamic sense, $\\delta P_{nad}\\equiv\\delta P-c_w^2\\delta\\rho$ where $c_w^2=\\dot P/\\dot\\rho$, usually becomes also negligible on superhorizon scales. Therefore one might think that the adiabatic limit is the same as thermodynamic adiabaticity. This is in fact not true. In other words, thermodynamic adiabaticity is not a sufficient condition for the conservation of $R_c$ on super-horizon scales. In this paper, we consider models that satisfies $\\d...
On the Navier-Stokes Equations for Exothermically Reacting Compressible Fluids
Institute of Scientific and Technical Information of China (English)
Gui-Qiang Chen; David Hoff; Konstantina Trivisa
2002-01-01
We analyze mathematical models governing planar flow of chemical reaction from unburnt gases to burnt gases in certain physical regimes in which diffusive effects such as viscosity and heat conduction are significant. These models can be then formulated as the Navier-Stokes equations for exothermically reacting compressible fluids. We first establish the existence and dynamic behavior, including stability, regularity, and large-time behavior, of global discontinuous solutions of large oscillation to the Navier-Stokes equations with constant adiabatic exponent γ and specific heat Cv. Our approach for the existence and regularity is to combine the difference approximation techniques with the energy methods, total variation estimates, and weak convergence arguments to deal with large jump discontinuities; and for large-time behavior is an a posteriori argument directly from the weak form of the equations. The approach and ideas we develop here can be applied to solving a more complicated model where γ and Cv vary as the phase changes; and we then describe this model in detail and contrast the results on the asymptotic behavior of the solutions of these two different models. We also discuss other physical models describing dynamic combustion.
Coïsson, M.; Barrera, G.; Celegato, F.; Martino, L.; Vinai, F.; Martino, P.; Ferraro, G.; Tiberto, P.
2016-10-01
An experimental setup for magnetic hyperthermia operating in non-adiabatic conditions is described. A thermodynamic model that takes into account the heat exchanged by the sample with the surrounding environment is developed. A suitable calibration procedure is proposed that allows the experimental validation of the model. Specific absorption rate can then be accurately determined just from the measurement of the sample temperature at the equilibrium steady state. The setup and the measurement procedure represent a simplification with respect to other systems requiring calorimeters or crucial corrections for heat flow. Two families of magnetic nanoparticles, one superparamagnetic and one characterised by larger sizes and static hysteresis, have been characterised as a function of field intensity, and specific absorption rate and intrinsic loss power have been obtained.
Fewest switches adiabatic surface hopping as applied to vibrational energy relaxation.
Käb, Günter
2006-03-01
In this contribution quantum/classical surface hopping methodology is applied to vibrational energy relaxation of a quantum oscillator in a classical heat bath. The model of a linearly damped (harmonic) oscillator is chosen which can be mapped onto the Brownian motion (Caldeira-Leggett) Hamiltonian. In the simulations Tully's fewest switches surface hopping scheme is adopted with inclusion of dephasing in the adiabatic basis using a simple decoherence algorithm. The results are compared to the predictions of a Redfield-type quantum master equation modeling using the classical heat bath force correlation function as input. Thereby a link is established between both types of quantum/classical approaches. Viewed from the latter perspective, surface hopping with dephasing may be interpreted as "on-the-fly" stochastic realization of a quantum/classical Pauli master equation. PMID:16509644
Žemlo, Gražina
2004-01-01
One of the images compression methods – fractal image compression is analyzed in the work. After work carried out, it is possible to state, that selecting parameters of method of fractal compression depends on user’s demands.
WELL-POSEDNESS OF INITIAL VALUE PROBLEM FOR EULER EQUATIONS OF INVISCID COMPRESSIBLE ADIABATIC FLUID
Institute of Scientific and Technical Information of China (English)
WANG Yue-peng
2005-01-01
The well-posedness of the initial value problem of the Euler equations was mainly discussed based on the stratification theory, and the necessary and sufficient conditions of well-posedness are presented for some representative initial or boundary value problem, thus the structure of solution space for local (exact) solution of the Euler equations is determined. Moreover the computation formulas of the analytical solution of the well-posed problem are also given.
Kawahara, Mutsuto
2016-01-01
This book focuses on the finite element method in fluid flows. It is targeted at researchers, from those just starting out up to practitioners with some experience. Part I is devoted to the beginners who are already familiar with elementary calculus. Precise concepts of the finite element method remitted in the field of analysis of fluid flow are stated, starting with spring structures, which are most suitable to show the concepts of superposition/assembling. Pipeline system and potential flow sections show the linear problem. The advection–diffusion section presents the time-dependent problem; mixed interpolation is explained using creeping flows, and elementary computer programs by FORTRAN are included. Part II provides information on recent computational methods and their applications to practical problems. Theories of Streamline-Upwind/Petrov–Galerkin (SUPG) formulation, characteristic formulation, and Arbitrary Lagrangian–Eulerian (ALE) formulation and others are presented with practical results so...
Compression limits in cascaded quadratic soliton compression
DEFF Research Database (Denmark)
Bache, Morten; Bang, Ole; Krolikowski, Wieslaw;
2008-01-01
Cascaded quadratic soliton compressors generate under optimal conditions few-cycle pulses. Using theory and numerical simulations in a nonlinear crystal suitable for high-energy pulse compression, we address the limits to the compression quality and efficiency.......Cascaded quadratic soliton compressors generate under optimal conditions few-cycle pulses. Using theory and numerical simulations in a nonlinear crystal suitable for high-energy pulse compression, we address the limits to the compression quality and efficiency....
Huang, Bormin
2011-01-01
Satellite Data Compression covers recent progress in compression techniques for multispectral, hyperspectral and ultra spectral data. A survey of recent advances in the fields of satellite communications, remote sensing and geographical information systems is included. Satellite Data Compression, contributed by leaders in this field, is the first book available on satellite data compression. It covers onboard compression methodology and hardware developments in several space agencies. Case studies are presented on recent advances in satellite data compression techniques via various prediction-
Integrated polarization rotator/converter by stimulated Raman adiabatic passage.
Xiong, Xiao; Zou, Chang-Ling; Ren, Xi-Feng; Guo, Guang-Can
2013-07-15
We proposed a polarization rotator inspired by stimulated Raman adiabatic passage model from quantum optics, which is composed of a signal waveguide and an ancillary waveguide. The two orthogonal modes in signal waveguide and the oblique mode in ancillary waveguide form a Λ-type three-level system. By controlling the width of signal waveguide and the gap between two waveguides, adiabatic conversion between two orthogonal modes can be realized in the signal waveguide. With such adiabatic passage, polarization conversion is completed within 150 μm length, with the efficiencies over 99% for both conversions between horizontal polarization and vertical polarization. In addition, such a polarization rotator is quite robust against fabrication error, allowing a wide range of tolerances for the rotator geometric parameters. Our work is not only significative to photonic simulations of coherent quantum phenomena with engineered photonic waveguides, but also enlightens the practical applications of these phenomena in optical device designs. PMID:23938558
Semiclassical approximations for adiabatic slow-fast systems
Teufel, Stefan
2012-01-01
In this letter we give a systematic derivation and justification of the semiclassical model for the slow degrees of freedom in adiabatic slow-fast systems first found by Littlejohn and Flynn [5]. The classical Hamiltonian obtains a correction due to the variation of the adiabatic subspaces and the symplectic form is modified by the curvature of the Berry connection. We show that this classical system can be used to approximate quantum mechanical expectations and the time-evolution of operators also in sub-leading order in the combined adiabatic and semiclassical limit. In solid state physics the corresponding semiclassical description of Bloch electrons has led to substantial progress during the recent years, see [1]. Here, as an illustration, we show how to compute the Piezo-current arising from a slow deformation of a crystal in the presence of a constant magnetic field.
Analysis and Simulation of Adiabatic Bend Transitions in Optical Fibers
Institute of Scientific and Technical Information of China (English)
YAO Lei; LOU Shu-Qin; JIAN Shui-Sheng
2009-01-01
A low-loss criterion for bend transitions in optical fibers is proposed. An optical fiber can be tightly bent with low loss to be adiabatic for the fundamental mode, provided that an approximate upper bound on the rate of change of bend curvature for a given bend curvature is satisfied. Two typical adiabatic bend transition paths, the optimum profile and linear profile, are analyzed and studied numerically. A realizable adiabatic transition with an Archimedean spiral profile is introduced for low bend loss in tightly bent optical fibers. Design of the transitions is based on modeling of the propagation and coupling characteristics of the core and cladding modes,which clearly illustrate the physical processes involved.
Adiabatic Quantum Computation is Equivalent to Standard Quantum Computation
Aharonov, D; Kempe, J; Landau, Z; Lloyd, S; Regev, O; Aharonov, Dorit; Dam, Wim van; Kempe, Julia; Landau, Zeph; Lloyd, Seth; Regev, Oded
2004-01-01
Adiabatic quantum computation has recently attracted attention in the physics and computer science communities, but its computational power has been unknown. We settle this question and describe an efficient adiabatic simulation of any given quantum algorithm, which implies that the adiabatic computation model and the conventional quantum circuit model are polynomially equivalent. Our result can be extended to the physically realistic setting of particles arranged on a two-dimensional grid with nearest neighbor interactions. The equivalence between the models provides a new vantage point from which to tackle the central issues in quantum computation, namely designing new quantum algorithms and constructing fault tolerant quantum computers. In particular, by translating the main open questions in quantum algorithms to the language of spectral gaps of sparse matrices, the result makes quantum algorithmic questions accessible to a wider scientific audience, acquainted with mathematical physics, expander theory a...
Adiabaticity and gravity theory independent conservation laws for cosmological perturbations
Romano, Antonio Enea; Sasaki, Misao
2015-01-01
We carefully study the implications of adiabaticity for the behavior of cosmological perturbations. There are essentially three similar but different definitions of non-adiabaticity: one is appropriate for a thermodynamic fluid $\\delta P_{nad}$, another is for a general matter field $\\delta P_{c,nad}$, and the last one is valid only on superhorizon scales. The first two definitions coincide if $c_s^2=c_w^2$ where $c_s$ is the propagation speed of the perturbation, while $c_w^2=\\dot P/\\dot\\rho$. Assuming the adiabaticity in the general sense, $\\delta P_{c,nad}=0$, we derive a relation between the lapse function in the comoving slicing $A_c$ and $\\delta P_{nad}$ valid for arbitrary matter field in any theory of gravity, by using only momentum conservation. The relation implies that as long as $c_s\
Global adiabaticity and non-Gaussianity consistency condition
Romano, Antonio Enea; Mooij, Sander; Sasaki, Misao
2016-10-01
In the context of single-field inflation, the conservation of the curvature perturbation on comoving slices, Rc, on super-horizon scales is one of the assumptions necessary to derive the consistency condition between the squeezed limit of the bispectrum and the spectrum of the primordial curvature perturbation. However, the conservation of Rc holds only after the perturbation has reached the adiabatic limit where the constant mode of Rc dominates over the other (usually decaying) mode. In this case, the non-adiabatic pressure perturbation defined in the thermodynamic sense, δPnad ≡ δP - cw2 δρ where cw2 = P ˙ / ρ ˙ , usually becomes also negligible on superhorizon scales. Therefore one might think that the adiabatic limit is the same as thermodynamic adiabaticity. This is in fact not true. In other words, thermodynamic adiabaticity is not a sufficient condition for the conservation of Rc on super-horizon scales. In this paper, we consider models that satisfy δPnad = 0 on all scales, which we call global adiabaticity (GA), which is guaranteed if cw2 = cs2 , where cs is the phase velocity of the propagation of the perturbation. A known example is the case of ultra-slow-roll (USR) inflation in which cw2 = cs2 = 1. In order to generalize USR we develop a method to find the Lagrangian of GA K-inflation models from the behavior of background quantities as functions of the scale factor. Applying this method we show that there indeed exists a wide class of GA models with cw2 = cs2, which allows Rc to grow on superhorizon scales, and hence violates the non-Gaussianity consistency condition.
Quantum Adiabatic Pumping by Modulating Tunnel Phase in Quantum Dots
Taguchi, Masahiko; Nakajima, Satoshi; Kubo, Toshihiro; Tokura, Yasuhiro
2016-08-01
In a mesoscopic system, under zero bias voltage, a finite charge is transferred by quantum adiabatic pumping by adiabatically and periodically changing two or more control parameters. We obtained expressions for the pumped charge for a ring of three quantum dots (QDs) by choosing the magnetic flux penetrating the ring as one of the control parameters. We found that the pumped charge shows a steplike behavior with respect to the variance of the flux. The value of the step heights is not universal but depends on the trajectory of the control parameters. We discuss the physical origin of this behavior on the basis of the Fano resonant condition of the ring.
Adiabatic theory of ionization of atoms by intense laser pulses
International Nuclear Information System (INIS)
As a first step towards the adiabatic theory of ionization of atoms by intense laser pulses, here we consider the simplest one-dimensional zero-range potential model. The asymptotic solution to the time-dependent Schroedinger equation in the adiabatic regime is obtained and the photoelectron spectrum is calculated. The factorization formula for the photoelectron spectrum in the back-rescattering region, first suggested by Morishita et al. [Phys. Rev. Lett. 100, 013903 (2008)] on the basis of ab initio calculations, is derived analytically.
Microstructure evolution mechanism in adiabatic shear band in TA2
Institute of Scientific and Technical Information of China (English)
杨扬; 熊俊; 杨续跃
2004-01-01
The micro structure evolution mechanism in adiabatic shear band in commercial pure titanium (TA2) at high strain rates(γ≈105 - 106/s) were studied. The nanosized recrystallized grains (about 50 nm in diameter) within the center of adiabatic shear band (ASB) were observed by means of transmission electronic microscope (TEM). A Rotational Dynamic Recrystallization (RDR) mechanism can explain the microstructure evolution (i. e. nanosized grains were formed within 5 - 10μs) in ASB. Kinetics calculations indicate that the recrystallized small grains are formed during the deformation and don't undergo significant growth by grain boundary migration after deformation.
Non-adiabatic pumping through interacting quantum dots
Cavaliere, Fabio; Governale, Michele; König, Jürgen
2009-01-01
We study non-adiabatic two-parameter charge and spin pumping through a single-level quantum dot with Coulomb interaction. For the limit of weak tunnel coupling and in the regime of pumping frequencies up to the tunneling rates, $\\Omega \\lesssim \\Gamma/\\hbar$, we perform an exact resummation of contributions of all orders in the pumping frequency. As striking non-adiabatic signatures, we find frequency-dependent phase shifts in the charge and spin currents, which allow for an effective single-...
Nanoscale resolution for fluorescence microscopy via adiabatic passage
Rubio, Juan Luis; Ahufinger, Verònica; Mompart, Jordi
2015-01-01
We propose the use of the subwavelength localization via adiabatic passage technique for fluorescence microscopy with nanoscale resolution in the far field. This technique uses a {\\Lambda}-type medium coherently coupled to two laser pulses: the pump, with a node in its spatial profile, and the Stokes. The population of the {\\Lambda} system is adiabatically transferred from one ground state to the other except at the node position, yielding a narrow population peak. This coherent localization allows fluorescence imaging with nanometer lateral resolution. We derive an analytical expression to asses the resolution and perform a comparison with the coherent population trapping and the stimulated-emission-depletion techniques.
Quantum-statistical equation-of-state models of dense plasmas: high-pressure Hugoniot shock adiabats
Pain, Jean-Christophe
2007-01-01
We present a detailed comparison of two self-consistent equation-of-state models which differ from their electronic contribution: the atom in a spherical cell and the atom in a jellium of charges. It is shown that both models are well suited for the calculation of Hugoniot shock adiabats in the high pressure range (1 Mbar-10 Gbar), and that the atom-in-a-jellium model provides a better treatment of pressure ionization. Comparisons with experimental data are also presented. Shell effects on shock adiabats are reviewed in the light of these models. They lead to additional features not only in the variations of pressure versus density, but also in the variations of shock velocity versus particle velocity. Moreover, such effects are found to be responsible for enhancement of the electronic specific heat.
DEFF Research Database (Denmark)
Blarke, Morten; Yazawa, Kazuaki; Shakouri, Ali;
2012-01-01
Increasing penetration levels of wind and solar power in the energy system call for the development of Smart Grid enabling technologies. As an alternative to expensive electro-chemical and mechanical storage options, the thermal energy demand in buildings offers a cost-effective option for interm...... CO2 emissions (reduced to zero), and lower operational costs (reduced by 72%). The results indicate that TB may be the most cost-effective Smart Grid enabling option for supporting higher penetration levels of intermittent renewables in the energy system.......Increasing penetration levels of wind and solar power in the energy system call for the development of Smart Grid enabling technologies. As an alternative to expensive electro-chemical and mechanical storage options, the thermal energy demand in buildings offers a cost-effective option...... for intermittency-friendly electricity consumption patterns. Combining hot and cold thermal storages with new high-pressure compressor technology that allows for flexible and simultaneous production of useful heat and cooling, the paper introduces and investigates the high-efficiency thermal battery (TB) concept...
Kimura, Jun-Ichi; Kawabata, Hiroshi
2014-06-01
numerical mass balance calculation model for the adiabatic melting of a dry to hydrous peridotite has been programmed in order to simulate the trace element compositions of basalts from mid-ocean ridges, back-arc basins, ocean islands, and large igneous provinces. The Excel spreadsheet-based calculator, Hydrous Adiabatic Mantle Melting Simulator version 1 (HAMMS1) uses (1) a thermodynamic model of fractional adiabatic melting of mantle peridotite, with (2) the parameterized experimental melting relationships of primitive to depleted mantle sources in terms of pressure, temperature, water content, and degree of partial melting. The trace element composition of the model basalt is calculated from the accumulated incremental melts within the adiabatic melting regime, with consideration for source depletion. The mineralogic mode in the primitive to depleted source mantle in adiabat is calculated using parameterized experimental results. Partition coefficients of the trace elements of mantle minerals are parameterized to melt temperature mostly from a lattice strain model and are tested using the latest compilations of experimental results. The parameters that control the composition of trace elements in the model are as follows: (1) mantle potential temperature, (2) water content in the source mantle, (3) depth of termination of adiabatic melting, and (4) source mantle depletion. HAMMS1 enables us to obtain the above controlling parameters using Monte Carlo fitting calculations and by comparing the calculated basalt compositions to primary basalt compositions. Additionally, HAMMS1 compares melting parameters with a major element model, which uses petrogenetic grids formulated from experimental results, thus providing better constraints on the source conditions.
A compressed hydrogen gas storage system with an integrated phase change material
DEFF Research Database (Denmark)
Mazzucco, Andrea; Rothuizen, Erasmus Damgaard; Jørgensen, Jens Erik;
2015-01-01
below the critical temperature of 85 °C, while filling the hydrogen at ambient temperature. Results show that a 10-mm-thick layer of paraffin wax can absorb enough heat to reduce the adiabatic temperature by 20 K when compared to a standard Type IV tank. The heat transfer from the gas to the phase...
DEFF Research Database (Denmark)
Mazzucco, Andrea; Rothuizen, Erasmus; Jørgensen, Jens-Erik;
2016-01-01
temperature. Results show that a 10-mm-thick layer of paraffin wax can absorb enough heat to reduce the adiabatic temperature by 20 K when compared to a standard Type IV tank, but its influence on the hydrogen peak temperature that occurs at the end of refueling is modest. The heat transfer from the gas...
Three-Dimensional Molecular Dynamics Simulation on Heat Propagation in Liquid Argon
Institute of Scientific and Technical Information of China (English)
郭英奎; 过增元; 梁新刚
2001-01-01
The propagation behaviour of an initial thermal perturbation in liquid argon is simulated by the molecular dynamics method. The 12-6 Lennard-Jones potential and mirror boundary conditions are employed in the 32768particle three-dimensional simulation. Macroscopic characteristics such as the kinetic temperature, pressure and momentum profiles are monitored during the simulation in order to examine the heat propagation behaviour under a timescale comparable with the relaxation time. The results show that the behaviour is still diffusionlike; no features predicted by the Cattaneo-Vernotte model have been found. The wave-like front of the local temperature may be caused by the adiabatic compression and expansion by the pressure wave generated by the thermal expansion.
Javidmand, Puya; Zareh, Masoud
2014-01-01
Capillary tubes are used as refrigerant controlling devices, expansion devices and also as heart of a small vapor compression refrigeration cycle. It connects outlet condenser to the inlet evaporator and balances the refrigeration cycle pressure and controls the refrigerant mass flux. Capillary tubes are relatively cheap, resulting in extensive implementations in small household refrigerators and freezers with nearly constant refrigeration load. In general, the inner diameter and length of a ...
Adiabatic CMB perturbations in pre-big bang string cosmology
DEFF Research Database (Denmark)
Enqvist, Kari; Sloth, Martin Snoager
2001-01-01
We consider the pre-big bang scenario with a massive axion field which starts to dominate energy density when oscillating in an instanton-induced potential and subsequently reheats the universe as it decays into photons, thus creating adiabatic CMB perturbations. We find that the fluctuations...
Fast Quasi-Adiabatic Gas Cooling: An Experiment Revisited
Oss, S.; Gratton, L. M.; Calza, G.; Lopez-Arias, T.
2012-01-01
The well-known experiment of the rapid expansion and cooling of the air contained in a bottle is performed with a rapidly responsive, yet very cheap thermometer. The adiabatic, low temperature limit is approached quite closely and measured with our apparatus. A straightforward theoretical model for this process is also presented and discussed.…
High beta lasing in micropillar cavities with adiabatic layer design
DEFF Research Database (Denmark)
Lermer, M.; Gregersen, Niels; Lorke, M.;
2013-01-01
We report on lasing in optically pumped adiabatic micropillar cavities, based on the AlAs/GaAs material system. A detailed study of the threshold pump power and the spontaneous emission β factor in the lasing regime for different diameters dc is presented. We demonstrate a reduction of the thresh...
Digitized adiabatic quantum computing with a superconducting circuit.
Barends, R; Shabani, A; Lamata, L; Kelly, J; Mezzacapo, A; Las Heras, U; Babbush, R; Fowler, A G; Campbell, B; Chen, Yu; Chen, Z; Chiaro, B; Dunsworth, A; Jeffrey, E; Lucero, E; Megrant, A; Mutus, J Y; Neeley, M; Neill, C; O'Malley, P J J; Quintana, C; Roushan, P; Sank, D; Vainsencher, A; Wenner, J; White, T C; Solano, E; Neven, H; Martinis, John M
2016-06-01
Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable. PMID:27279216
Adiabatic frequency conversion with a sign flip in the coupling
Hristova, H. S.; Rangelov, A. A.; Montemezzani, G.; Vitanov, N. V.
2016-09-01
Adiabatic frequency conversion is a method recently developed in nonlinear optics [H. Suchowski, D. Oron, A. Arie, and Y. Silberberg, Phys. Rev. A 78, 063821 (2008), 10.1103/PhysRevA.78.063821], using ideas from the technique of rapid adiabatic passage (RAP) via a level crossing in quantum physics. In this method, the coupling coefficients are constant and the phase mismatch is chirped adiabatically. In this work, we propose another method for adiabatic frequency conversion, in which the phase mismatch is constant and the coupling is a pulse-shaped function with a sign flip (i.e., a phase step of π ) at its maximum. Compared to the RAP method, our technique has comparable efficiency but it is simpler to implement for it only needs two bulk crystals with opposite χ(2 ) nonlinearity. Moreover, because our technique requires constant nonzero frequency mismatch and has zero conversion efficiency on exact frequency matching, it can be used as a frequency filter.
Digitized adiabatic quantum computing with a superconducting circuit
Barends, R.; Shabani, A.; Lamata, L.; Kelly, J.; Mezzacapo, A.; Heras, U. Las; Babbush, R.; Fowler, A. G.; Campbell, B.; Chen, Yu; Chen, Z.; Chiaro, B.; Dunsworth, A.; Jeffrey, E.; Lucero, E.; Megrant, A.; Mutus, J. Y.; Neeley, M.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Solano, E.; Neven, H.; Martinis, John M.
2016-06-01
Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.
A Quantum Adiabatic Algorithm for Factorization and Its Experimental Implementation
Peng, Xinhua; Liao, Zeyang; Xu, Nanyang; Qin, Gan; Zhou, Xianyi; Suter, Dieter; Du, Jiangfeng
2008-01-01
We propose an adiabatic quantum algorithm capable of factorizing numbers, using fewer qubits than Shor's algorithm. We implement the algorithm in an NMR quantum information processor and experimentally factorize the number 21. Numerical simulations indicate that the running time grows only quadratically with the number of qubits.
Evolutions of Yang Phase Under Cyclic Condition and Adiabatic Condition
Institute of Scientific and Technical Information of China (English)
QIAN Shang-Wu; GU Zhi-Yu
2005-01-01
There are three non-integrable phases in literatures: Berry phase, Aharonov-Anandan phase, and Yang phase. This article discusses the evolutions of Yang phase under the cyclic condition and the adiabatic condition for the generaltime-dependent harmonic oscillator, thus reveals the intimate relations between these three non-integrable phases.
Flat FRW Cosmologies with Adiabatic Matter Creation Kinematic tests
Lima, J A S
1999-01-01
Some observational consequences of a cosmological scenario driven by adiabatic matter creation are investigated. Exact expressions for the lookback time, age of the universe, luminosity distance, angular diameter, and galaxy number counts redshift relations are derived and their meaning discussed in detail. The expressions of the conventional FRW models are significantly modified and provide a powerful method to limit the parameters of the models.
A Kinetic Study of the Adiabatic Polymerization of Acrylamide.
Thomson, R. A. M.
1986-01-01
Discusses theory, procedures, and results for an experiment which demonstrates the application of basic physics to chemical problems. The experiment involves the adiabatic process, in which polymerization carried out in a vacuum flask is compared to the theoretical prediction of the model with the temperature-time curve obtained in practice. (JN)
Adiabatic and diabatic aerosol transport to the Jungfraujoch
Energy Technology Data Exchange (ETDEWEB)
Lugauer, M.; Baltensperger, U.; Furger, M.; Jost, D.T.; Schwikowski, M.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1997-09-01
Synoptic scale vertical motion, here detected by the geopotential height of the 500 hPa surface, mainly accounts for the aerosol transport to the Jungfraujoch in winter. In summer, diabatic convection provides the dominant vertical transport mechanism. Nevertheless, synoptic scale adiabatic motion still determines whether diabatic convection can develop. (author) 2 figs., 2 refs.
Evolutions of Yang Phase Under Cyclic Condition and Adiabatic Condition
International Nuclear Information System (INIS)
There are three non-integrable phases in literatures: Berry phase, Aharonov-Anandan phase, and Yang phase. This article discusses the evolutions of Yang phase under the cyclic condition and the adiabatic condition for the general time-dependent harmonic oscillator, thus reveals the intimate relations between these three non-integrable phases.
Digitized adiabatic quantum computing with a superconducting circuit.
Barends, R; Shabani, A; Lamata, L; Kelly, J; Mezzacapo, A; Las Heras, U; Babbush, R; Fowler, A G; Campbell, B; Chen, Yu; Chen, Z; Chiaro, B; Dunsworth, A; Jeffrey, E; Lucero, E; Megrant, A; Mutus, J Y; Neeley, M; Neill, C; O'Malley, P J J; Quintana, C; Roushan, P; Sank, D; Vainsencher, A; Wenner, J; White, T C; Solano, E; Neven, H; Martinis, John M
2016-06-08
Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.
Numerical study on lithium titanate battery thermal response under adiabatic condition
International Nuclear Information System (INIS)
Highlights: • The thermal behavior of lithium titanate battery during cycling was investigated. • The temperature rate in charging was less than that of discharging in the cycling. • The temperature difference was less than 0.02 °C at 0.5 C in adiabatic condition. • The temperature distribution and thermal runaway of the battery were predicted. - Abstract: To analyze the thermal behavior of 945 mA h lithium titanate battery during charging and discharging processes, the experimental and numerical studies are performed in this work. The cathode and anode of the 945 mA h lithium titanate soft package battery are the lithium nickel–cobalt–manganese-oxide and lithium titanate, respectively. In the experiment, an Accelerating Rate Calorimeter combined with battery cycler is employed to investigate the electrochemical–thermal behavior during charge–discharge cycling under the adiabatic condition. In numerical simulation, one electrochemical-thermal model is adopted to predict the thermal response and validated with the experimental results. From both experimental and simulated results, the profile of potential and current, the heat generation, the temperature, the temperature changing rate and the temperature distribution in the cell are obtained and thermal runaway is predicted. The analysis of the electrochemical and thermal behavior is beneficial for the commercial application of lithium titanate battery in the fields of electric vehicles and hybrid electric vehicles
Energy-efficient miniature-scale heat pumping based on shape memory alloys
Ossmer, Hinnerk; Wendler, Frank; Gueltig, Marcel; Lambrecht, Franziska; Miyazaki, Shuichi; Kohl, Manfred
2016-08-01
Cooling and thermal management comprise a major part of global energy consumption. The by far most widespread cooling technology today is vapor compression, reaching rather high efficiencies, but promoting global warming due to the use of environmentally harmful refrigerants. For widespread emerging applications using microelectronics and micro-electro-mechanical systems, thermoelectrics is the most advanced technology, which however hardly reaches coefficients of performance (COP) above 2.0. Here, we introduce a new approach for energy-efficient heat pumping using the elastocaloric effect in shape memory alloys. This development is mainly targeted at applications on miniature scales, while larger scales are envisioned by massive parallelization. Base materials are cold-rolled textured Ti49.1Ni50.5Fe0.4 foils of 30 μm thickness showing an adiabatic temperature change of +20/‑16 K upon superelastic loading/unloading. Different demonstrator layouts consisting of mechanically coupled bridge structures with large surface-to-volume ratios are developed allowing for control by a single actuator as well as work recovery. Heat transfer times are in the order of 1 s, being orders of magnitude faster than for bulk geometries. Thus, first demonstrators achieve values of specific heating and cooling power of 4.5 and 2.9 W g‑1, respectively. A maximum temperature difference of 9.4 K between heat source and sink is reached within 2 min. Corresponding COP on the device level are 4.9 (heating) and 3.1 (cooling).
Energy-efficient miniature-scale heat pumping based on shape memory alloys
Ossmer, Hinnerk; Wendler, Frank; Gueltig, Marcel; Lambrecht, Franziska; Miyazaki, Shuichi; Kohl, Manfred
2016-08-01
Cooling and thermal management comprise a major part of global energy consumption. The by far most widespread cooling technology today is vapor compression, reaching rather high efficiencies, but promoting global warming due to the use of environmentally harmful refrigerants. For widespread emerging applications using microelectronics and micro-electro-mechanical systems, thermoelectrics is the most advanced technology, which however hardly reaches coefficients of performance (COP) above 2.0. Here, we introduce a new approach for energy-efficient heat pumping using the elastocaloric effect in shape memory alloys. This development is mainly targeted at applications on miniature scales, while larger scales are envisioned by massive parallelization. Base materials are cold-rolled textured Ti49.1Ni50.5Fe0.4 foils of 30 μm thickness showing an adiabatic temperature change of +20/-16 K upon superelastic loading/unloading. Different demonstrator layouts consisting of mechanically coupled bridge structures with large surface-to-volume ratios are developed allowing for control by a single actuator as well as work recovery. Heat transfer times are in the order of 1 s, being orders of magnitude faster than for bulk geometries. Thus, first demonstrators achieve values of specific heating and cooling power of 4.5 and 2.9 W g-1, respectively. A maximum temperature difference of 9.4 K between heat source and sink is reached within 2 min. Corresponding COP on the device level are 4.9 (heating) and 3.1 (cooling).
Bartlett, J.; Hardy, G.; Hepburn, I. D.; Brockley-Blatt, C.; Coker, P.; Crofts, E.; Winter, B.; Milward, S.; Stafford-Allen, R.; Brownhill, M.; Reed, J.; Linder, M.; Rando, N.
2010-09-01
This paper describes the design, development and performance of the engineering model double adiabatic demagnetization refrigerator (dADR) built and tested under contract to the European Space Agency for its former mission XEUS (now IXO). The dADR operates from a 4 K bath and has a measured recycle and hold time (with a parasitic load of 2.34 μW) at 50 mK of 15 h and 10 h, respectively. It is shown that the performance can be significantly improved by operating from a lower bath temperature and replacing the current heat switches with tungsten magnetoresistive (MR) heat switches, which significantly reduce the parasitic heat load. Performing the latter gives an anticipated recycle and hold time of 2 and 29 h (with a 1 μW applied heat load in addition to the parasitic load), respectively. Such improved performance allows for a reduction in mass of the dADR from 32 kg to 10 kg by operating from a 2.5 K bath (which could be reduced further by optimising the magnet design). Ultimately, continuous operation could be achieved by linking two dADRs to a common detector stage and operating them alternately. Based on this design the mass of the continuous ADR is estimated to be about 4.5 kg.
Cruz-Orea, A.; Bentefour, E. H.; Jamée, P.; Chirtoc, M.; Glorieux, C.; Pitsi, G.; Thoen, J.
2003-01-01
Starch is one of the most important carbohydrate sources in human nutrition. For the thermal analysis of starch, techniques such as differential scanning calorimetry have been extensively used. As an alternative, we have applied a photopyroelectric (PPE) configuration and adiabatic scanning calorimetry (ASC) to study the thermal properties of starch-water systems. For this study we used nixtamalized corn flour and potato starch with different quantities of distilled water, in order to obtain samples with different moisture content. By using PPE and ASC methods we have measured, for each technique separately, the heat capacity by unit volume (ρcp) at room temperature for a corn flour sample at 90% moisture. The obtained values agree within experimental uncertainty. By using these techniques we also studied the thermal behavior of potato starch, at 80% moisture, in the temperature range where phase transitions occur. In this case the PPE signal phase could be used as a sensitive and versatile monitor for phase transitions.
Stimulated Raman adiabatic passage for improved performance of a cold-atom electron and ion source
Sparkes, B. M.; Murphy, D.; Taylor, R. J.; Speirs, R. W.; McCulloch, A. J.; Scholten, R. E.
2016-08-01
We implement high-efficiency coherent excitation to a Rydberg state using stimulated Raman adiabatic passage in a cold-atom electron and ion source. We achieve an efficiency of 60% averaged over the laser excitation volume with a peak efficiency of 82%, a 1.6 times improvement relative to incoherent pulsed-laser excitation. Using pulsed electric field ionization of the Rydberg atoms we create electron bunches with durations of 250 ps. High-efficiency excitation will increase source brightness, crucial for ultrafast electron diffraction experiments, and coherent excitation to high-lying Rydberg states could allow for the reduction of internal bunch heating and the creation of a high-speed single-ion source.
Extended adiabatic blast waves and a model of the soft X-ray background. [interstellar matter
Cox, D. P.; Anderson, P. R.
1981-01-01
An analytical approximation is generated which follows the development of an adiabatic spherical blast wave in a homogeneous ambient medium of finite pressure. An analytical approximation is also presented for the electron temperature distribution resulting from coulomb collisional heating. The dynamical, thermal, ionization, and spectral structures are calculated for blast waves of energy E sub 0 = 5 x 10 to the 50th power ergs in a hot low-density interstellar environment. A formula is presented for estimating the luminosity evolution of such explosions. The B and C bands of the soft X-ray background, it is shown, are reproduced by such a model explosion if the ambient density is about .000004 cm, the blast radius is roughly 100 pc, and the solar system is located inside the shocked region. Evolution in a pre-existing cavity with a strong density gradient may, it is suggested, remove both the M band and OVI discrepancies.
Non-adiabatic radiative collapse of a relativistic star under different initial conditions
Indian Academy of Sciences (India)
Ranjan Sharma; Ramesh Tikekar
2012-09-01
We examine the role of space-time geometry in the non-adiabatic collapse of a star dissipating energy in the form of radial heat flow, studying its evolution under different initial conditions. The collapse of a star filled with a homogeneous perfect fluid is compared with that of a star filled with inhomogeneous imperfect fluid under anisotropic pressure. Both the configurations are spherically symmetric. However, in the latter case, the physical space = constant of the configurations endowed with spheroidal or pseudospheroidal geometry is assumed to be inhomogeneous. It is observed that as long as the collapse is shear-free, its evolution depends only on the mass and size of the star at the onset of collapse.
Nitrogen oxide reduction strategies for compression ignition engines
Chapman, Elana M.
2008-05-01
The scope of this investigation is to explore strategies to reduce NOx emissions from compression ignition engines. Two methods are presented in this collection of studies: (1) NOx reduction accomplished through a change in fuel formulation, specifically through a change in the saturated fuel carbon chains of biodiesel; and (2) NOx reduction accomplished through a mixed mode combustion process utilizing a fumigated fuel and a pilot injection of diesel fuel. In the first study, a light duty diesel engine was used to investigate the change in saturation of a biodiesel fuel and its impact on NOx emissions. Previous studies have shown that a reduction in the iodine value of a biodiesel fuel produces a reduction in NOx emissions. The iodine value of the fuel is reduced through the saturation of the C18 molecules via hydrogenation of biodiesel fuel. Experiments were performed at several speeds and loads without exhaust gas recirculation (EGR), and a NOx reduction with the hydrogenated diesel fuel was observed. For all the modes studied, the NOx emission was higher for the biodiesel and lower for the hydrogenated biodiesel in comparison to the ultra low sulfur diesel (ULSD) fuel. Results from the calculation of the adiabatic flame temperature shows that the results could be explained by the difference in adiabatic flame temperature of the fuel, thus influencing the prompt NOx contribution in addition to the thermal contribution. Since the adiabatic flame temperatures are similar for the hydrogenated biodiesel and the ULSD, yet the NOx reduction with the hydrogenated biodiesel is much lower than the ULSD levels, another explanation for the reduction is suggested: the additional prompt NOx contribution from the change in fuel chemistry. The second study investigated the NOx reductions which could be achieved with a mixed mode combustion process utilizing a fumigated fuel and a pilot injection of diesel fuel. In this research, the fumigated fuel was dimethyl ether (DME) and
Super-adiabatic combustion in Al2O3 and SiC coated porous media for thermoelectric power conversion
International Nuclear Information System (INIS)
The combustion of ultra-lean fuel/air mixtures provides an efficient way to convert the chemical energy of hydrocarbons and low-calorific fuels into useful power. Matrix-stabilized porous medium combustion is an advanced technique in which a solid porous medium within the combustion chamber conducts heat from the hot gaseous products in the upstream direction to preheat incoming reactants. This heat recirculation extends the standard flammability limits, allowing the burning of ultra-lean and low-calorific fuel mixtures and resulting a combustion temperature higher than the thermodynamic equilibrium temperature of the mixture (i.e., super-adiabatic combustion). The heat generated by this combustion process can be converted into electricity with thermoelectric generators, which is the goal of this study. The design of a porous media burner coupled with a thermoelectric generator and its testing are presented. The combustion zone media was a highly-porous alumina matrix interposed between upstream and downstream honeycomb structures with pore sizes smaller than the flame quenching distance, preventing the flame from propagating outside of the central section. Experimental results include temperature distributions inside the combustion chamber and across a thermoelectric generator; along with associated current, voltage and power output values. Measurements were obtained for a catalytically inert Al2O3 medium and a SiC coated medium, which was tested for the ability to catalyze the super-adiabatic combustion. The combustion efficiency was obtained for stoichiometric and ultra-lean (near the lean flammability limit) mixtures of CH4 and air. - Highlights: • Design of a porous burner coupled with a thermoelectric module. • Super-adiabatic combustion in a highly-porous ceramic matrix was investigated. • Both alumina and silicon carbide ceramic surfaces were used as porous media. • Catalytic properties of Al2O3 and SiC ceramic surfaces were studied
Non-adiabatic dynamics of molecules in optical cavities
Energy Technology Data Exchange (ETDEWEB)
Kowalewski, Markus, E-mail: mkowalew@uci.edu; Bennett, Kochise; Mukamel, Shaul, E-mail: smukamel@uci.edu [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States)
2016-02-07
Strong coupling of molecules to the vacuum field of micro cavities can modify the potential energy surfaces thereby opening new photophysical and photochemical reaction pathways. While the influence of laser fields is usually described in terms of classical field, coupling to the vacuum state of a cavity has to be described in terms of dressed photon-matter states (polaritons) which require quantized fields. We present a derivation of the non-adiabatic couplings for single molecules in the strong coupling regime suitable for the calculation of the dressed state dynamics. The formalism allows to use quantities readily accessible from quantum chemistry codes like the adiabatic potential energy surfaces and dipole moments to carry out wave packet simulations in the dressed basis. The implications for photochemistry are demonstrated for a set of model systems representing typical situations found in molecules.
Crack propagation of Ti alloy via adiabatic shear bands
International Nuclear Information System (INIS)
This study was focused on the characterization of the origin and mechanism of crack propagation as a result of hot induction bending of Ti alloy. Plates of Ti–6Al–4V alloy with 12.5 mm of thickness were submitted to hot induction bending below the beta transus temperature. Optical and scanning electron microscopy analysis showed crack formation in the tensile zone. Microstructural evidence showed that cracks propagate through the adiabatic shear bands by Dimple-Void mechanism. However, voids formation before shear banding also occurred. In both mechanisms adiabatic shear bands are formed via dynamic recrystallization where the alpha–beta interphase works as stress concentrator promoting the formation of dimples and voids
On some issues of gravitationally induced adiabatic particle productions
Pan, Supriya; Pramanik, Souvik
2016-01-01
In this work, we investigate the current accelerating universe driven by the gravitationally induced adiabatic matter creation process. To elaborate the underlying cognitive content, here we consider three models of adiabatic particle creation and constrain the model parameters by fitting the models with the Union 2.1 data set using $\\chi^2$ minimization technique. The models are analyzed by two geometrical and model independent tests, viz., cosmography and $Om$-diagnostic, which are widely used to distinguish the cosmological models from $\\Lambda$CDM. We also compared present values of those model independent parameters with that of the flat $\\Lambda$CDM model. Finally, the validity of the generalized second law of thermodynamics and the condition of thermodynamic equilibrium for the particle production models have been tested.
Excitation energies along a range-separated adiabatic connection
Rebolini, Elisa; Teale, Andrew M; Helgaker, Trygve; Savin, Andreas
2014-01-01
We present a study of the variation of total energies and excitationenergies along a range-separated adiabatic connection. This connectionlinks the non-interacting Kohn-Sham electronic system to the physicalinteracting system by progressively switching on theelectron-electron interactions whilst simultaneously adjusting aone-electron effective potential so as to keep the ground-statedensity constant. The interactions are introduced in arange-dependent manner, first introducing predominantly long-range,and then all-range, interactions as the physical system is approached,as opposed to the conventional adiabatic connection where theinteractions are introduced by globally scaling the standard Coulomb interaction.Reference data are reported for the He and Be atoms and the H2molecule, obtained by calculating the short-range effective potentialat the full configuration-interaction level using Lieb'sLegendre-transform approach. As the strength of the electron-electroninteractions increases, the excitation energies, ...
Adiabatic far-field sub-diffraction imaging
Cang, Hu; Salandrino, Alessandro; Wang, Yuan; Zhang, Xiang
2015-08-01
The limited resolution of a conventional optical imaging system stems from the fact that the fine feature information of an object is carried by evanescent waves, which exponentially decays in space and thus cannot reach the imaging plane. We introduce here an adiabatic lens, which utilizes a geometrically conformal surface to mediate the interference of slowly decompressed electromagnetic waves at far field to form images. The decompression is satisfying an adiabatic condition, and by bridging the gap between far field and near field, it allows far-field optical systems to project an image of the near-field features directly. Using these designs, we demonstrated the magnification can be up to 20 times and it is possible to achieve sub-50 nm imaging resolution in visible. Our approach provides a means to extend the domain of geometrical optics to a deep sub-wavelength scale.
DESIGN OF TERNARY COUNTER BASED ON ADIABATIC DOMINO CIRCUIT
Institute of Scientific and Technical Information of China (English)
Yang Qiankun; Wang Pengjun; Zheng Xuesong
2013-01-01
By researching the ternary counter and low power circuit design method,a novel design of low power ternary Domino counter on switch-level is proposed.Firstly,the switch-level structure expression of ternary loop operation circuit with enable pin is derived according to the switch-signal theory,and the one bit ternary counter is obtained combining the ternary adiabatic Domino literal operation circuit and buffer.Then the switch-level structure expression of enable signal circuit is derived,and the four bits ternary counter is obtained by cascade connection.Finally,the circuit is simulated by Spice tool and the output waveforms transform in proper order indicating that the logic function is correct.The energy consumption of the four bits ternary adiabatic Domino counter is 63％ less than the conventional Domino counterpart.
Adiabatic theory of solitons fed by dispersive waves
Pickartz, Sabrina; Bandelow, Uwe; Amiranashvili, Shalva
2016-09-01
We consider scattering of low-amplitude dispersive waves at an intense optical soliton which constitutes a nonlinear perturbation of the refractive index. Specifically, we consider a single-mode optical fiber and a group velocity matched pair: an optical soliton and a nearly perfectly reflected dispersive wave, a fiber-optical analog of the event horizon. By combining (i) an adiabatic approach that is used in soliton perturbation theory and (ii) scattering theory from quantum mechanics, we give a quantitative account of the evolution of all soliton parameters. In particular, we quantify the increase in the soliton peak power that may result in the spontaneous appearance of an extremely large, so-called champion soliton. The presented adiabatic theory agrees well with the numerical solutions of the pulse propagation equation. Moreover, we predict the full frequency band of the scattered dispersive waves and explain an emerging caustic structure in the space-time domain.
Crack propagation of Ti alloy via adiabatic shear bands
Energy Technology Data Exchange (ETDEWEB)
Mendoza, I., E-mail: ivanmendozabravo@gmail.com [Instituto Tecnológico de Veracruz (Mexico); Villalobos, D. [Instituto Tecnológico de Veracruz (Mexico); Alexandrov, B.T. [The Ohio State University (United States)
2015-10-01
This study was focused on the characterization of the origin and mechanism of crack propagation as a result of hot induction bending of Ti alloy. Plates of Ti–6Al–4V alloy with 12.5 mm of thickness were submitted to hot induction bending below the beta transus temperature. Optical and scanning electron microscopy analysis showed crack formation in the tensile zone. Microstructural evidence showed that cracks propagate through the adiabatic shear bands by Dimple-Void mechanism. However, voids formation before shear banding also occurred. In both mechanisms adiabatic shear bands are formed via dynamic recrystallization where the alpha–beta interphase works as stress concentrator promoting the formation of dimples and voids.
Robust quantum logic in neutral atoms via adiabatic Rydberg dressing
Keating, Tyler; Cook, Robert L.; Hankin, Aaron M.; Jau, Yuan-Yu; Biedermann, Grant W.; Deutsch, Ivan H.
2015-01-01
We study a scheme for implementing a controlled-Z (cz) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By employing adiabatic dressing of the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise because of atomic thermal motion. In addition, the adiabatic protocol allows for a Doppler-free configuration that involves counterpropagating lasers in a σ+/σ- orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual motional error is dominated by dipole-dipole forces acting on doubly excited Rydberg atoms when the blockade is imperfect. For reasonable parameters, with qubits encoded into the clock states of 133Cs, we predict that our protocol could produce a cz gate in <10 μ s with error probability on the order of 10-3.
Reif, Maria M; Hünenberger, Philippe H
2011-04-14
The raw single-ion solvation free energies computed from atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions (finite or periodic system, system or box size) and treatment of electrostatic interactions (Coulombic, lattice-sum, or cutoff-based) used during these simulations. However, as shown by Kastenholz and Hünenberger [J. Chem. Phys. 124, 224501 (2006)], correction terms can be derived for the effects of: (A) an incorrect solvent polarization around the ion and an incomplete or/and inexact interaction of the ion with the polarized solvent due to the use of an approximate (not strictly Coulombic) electrostatic scheme; (B) the finite-size or artificial periodicity of the simulated system; (C) an improper summation scheme to evaluate the potential at the ion site, and the possible presence of a polarized air-liquid interface or of a constraint of vanishing average electrostatic potential in the simulated system; and (D) an inaccurate dielectric permittivity of the employed solvent model. Comparison with standard experimental data also requires the inclusion of appropriate cavity-formation and standard-state correction terms. In the present study, this correction scheme is extended by: (i) providing simple approximate analytical expressions (empirically-fitted) for the correction terms that were evaluated numerically in the above scheme (continuum-electrostatics calculations); (ii) providing correction terms for derivative thermodynamic single-ion solvation properties (and corresponding partial molar variables in solution), namely, the enthalpy, entropy, isobaric heat capacity, volume, isothermal compressibility, and isobaric expansivity (including appropriate standard-state correction terms). The ability of the correction scheme to produce methodology-independent single-ion solvation free energies based on atomistic simulations is tested in the case of Na(+) hydration, and the nature and magnitude of the correction terms for
A Compressive Superresolution Display
Heide, Felix
2014-06-22
In this paper, we introduce a new compressive display architecture for superresolution image presentation that exploits co-design of the optical device configuration and compressive computation. Our display allows for superresolution, HDR, or glasses-free 3D presentation.
DEFF Research Database (Denmark)
Denisov, S.; Flach, S.; Ovchinnikov, A. A.;
2002-01-01
We consider low-dimensional dynamical systems exposed to a heat bath and to additional ac fields. The presence of these ac fields may lead to a breaking of certain spatial or temporal symmetries, which in turn cause nonzero averages of relevant observables. Nonlinear (non)adiabatic response is em...... is employed to explain the effect. We consider a case of a particle in a periodic potential as an example and discuss the relevant symmetry breakings and the mechanisms of rectification of the current in such a system....
Hypercomputability of quantum adiabatic processes: Fact versus Prejudices
Kieu, T D
2005-01-01
We give an overview of a quantum adiabatic algorithm for Hilbert's tenth problem, including some discussions on its fundamental aspects and the emphasis on the probabilistic correctness of its findings. For the purpose of illustration, the numerical simulation results of some simple Diophantine equations are presented. We also discuss some prejudicial misunderstandings as well as some plausible difficulties faced by the algorithm in its physical implementation.
High-Fidelity Entangled Bell States via Shortcuts to Adiabaticity
Paul, Koushik
2016-01-01
We present a couple of protocols based on shortcut to adiabaticity techniques for rapid generation of robust entangled Bell states in a system of two two-state systems. Our protocols rely on the so-called transitionless quantum driving (TQD) algorithm and Lewis-Riesenfeld invariant (LRI) method. Both TQD and LRI methods result in high fidelity in population transfer.Our study shows that it is possible to prepare an entangled state in infinitely short time without losing robustness and efficiency.
Adiabaticity and gravity theory independent conservation laws for cosmological perturbations
Romano, Antonio Enea; Mooij, Sander; Sasaki, Misao
2016-04-01
We carefully study the implications of adiabaticity for the behavior of cosmological perturbations. There are essentially three similar but different definitions of non-adiabaticity: one is appropriate for a thermodynamic fluid δPnad, another is for a general matter field δPc,nad, and the last one is valid only on superhorizon scales. The first two definitions coincide if cs2 = cw2 where cs is the propagation speed of the perturbation, while cw2 = P ˙ / ρ ˙ . Assuming the adiabaticity in the general sense, δPc,nad = 0, we derive a relation between the lapse function in the comoving slicing Ac and δPnad valid for arbitrary matter field in any theory of gravity, by using only momentum conservation. The relation implies that as long as cs ≠cw, the uniform density, comoving and the proper-time slicings coincide approximately for any gravity theory and for any matter field if δPnad = 0 approximately. In the case of general relativity this gives the equivalence between the comoving curvature perturbation Rc and the uniform density curvature perturbation ζ on superhorizon scales, and their conservation. This is realized on superhorizon scales in standard slow-roll inflation. We then consider an example in which cw =cs, where δPnad = δPc,nad = 0 exactly, but the equivalence between Rc and ζ no longer holds. Namely we consider the so-called ultra slow-roll inflation. In this case both Rc and ζ are not conserved. In particular, as for ζ, we find that it is crucial to take into account the next-to-leading order term in ζ's spatial gradient expansion to show its non-conservation, even on superhorizon scales. This is an example of the fact that adiabaticity (in the thermodynamic sense) is not always enough to ensure the conservation of Rc or ζ.
Geometry of adiabatic Hamiltonians for two-level quantum systems
International Nuclear Information System (INIS)
We present the formulation of the problem of the coherent dynamics of quantum mechanical two-level systems in the adiabatic region in terms of the differential geometry of plane curves. We show that there is a natural plane curve corresponding to the Hamiltonian of the system for which the geometrical quantities have a simple physical interpretation. In particular, the curvature of the curve has the role of the nonadiabatic coupling. (paper)
Single-parameter adiabatic charge pumping in carbon nanotube resonators
Perroni, C. A.; Nocera, A.; Cataudella, V.
2013-01-01
Single-parameter adiabatic charge pumping, induced by a nearby radio-frequency antenna, is achieved in suspended carbon nanotubes close to the mechanical resonance. The charge pumping is due to an important dynamic adjustment of the oscillating motion to the antenna signal and it is different from the mechanism active in the two-parameter pumping. Finally, the second harmonic oscillator response shows an interesting relationship with the first harmonic that should be experimentally observed.
Quantum pumping with adiabatically modulated barriers in graphene
Zhu, Rui; Chen, Huiming
2009-01-01
We study the adiabatic quantum pumping characteristics in the graphene modulated by two oscillating gate potentials out of phase. The angular and energy dependence of the pumped current is presented. The direction of the pumped current can be reversed when a high barrier demonstrates stronger transparency than a low one, which results from the Klein paradox. The underlying physics of the pumping process is illuminated.
Adiabatic trapping in coupled kinetic Alfven-acoustic waves
Energy Technology Data Exchange (ETDEWEB)
Shah, H. A.; Ali, Z. [Department of Physics, G.C. University, 54000 Lahore (Pakistan); Masood, W. [COMSATS, Institute of Information Technology, Park Road, Chak Shahzad, Islamabad 44000 (Pakistan); National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Theoretical Plasma Physics Division, P. O. Nilore, Islamabad (Pakistan)
2013-03-15
In the present work, we have discussed the effects of adiabatic trapping of electrons on obliquely propagating Alfven waves in a low {beta} plasma. Using the two potential theory and employing the Sagdeev potential approach, we have investigated the existence of arbitrary amplitude coupled kinetic Alfven-acoustic solitary waves in both the sub and super Alfvenic cases. The results obtained have been analyzed and presented graphically and can be applied to regions of space where the low {beta} assumption holds true.
Highly stripped ions on hydrogen atoms: the adiabatic approach
International Nuclear Information System (INIS)
The simple Lorentzian form for the adiabatic radial matrix elements which dominate low-energy charge transfer in highly stripped systems is exploited to derive the S matrix for the Asub(Z)sup(Z+) + H(1s) → Asub(Z)sup(Z-1)+ + H+ scattering process. The approximations used are discussed and the results of the theory are compared with measured He2+ + H(1s) → He+ + H+ cross sections. Agreement is satisfactory for low velocities. (author)
Adiabatic shear mechanisms for the hard cutting process
Yue, Caixu; Wang, Bo; Liu, Xianli; Feng, Huize; Cai, Chunbin
2015-05-01
The most important consequence of adiabatic shear phenomenon is formation of sawtooth chip. Lots of scholars focused on the formation mechanism of sawtooth, and the research often depended on experimental approach. For the present, the mechanism of sawtooth chip formation still remains some ambiguous aspects. This study develops a combined numerical and experimental approach to get deeper understanding of sawtooth chip formation mechanism for Polycrystalline Cubic Boron Nitride (PCBN) tools orthogonal cutting hard steel GCr15. By adopting the Johnson-Cook material constitutive equations, the FEM simulation model established in this research effectively overcomes serious element distortions and cell singularity in high strain domain caused by large material deformation, and the adiabatic shear phenomenon is simulated successfully. Both the formation mechanism and process of sawtooth are simulated. Also, the change features regarding the cutting force as well as its effects on temperature are studied. More specifically, the contact of sawtooth formation frequency with cutting force fluctuation frequency is established. The cutting force and effect of cutting temperature on mechanism of adiabatic shear are investigated. Furthermore, the effects of the cutting condition on sawtooth chip formation are researched. The researching results show that cutting feed has the most important effect on sawtooth chip formation compared with cutting depth and speed. This research contributes a better understanding of mechanism, feature of chip formation in hard turning process, and supplies theoretical basis for the optimization of hard cutting process parameters.
Adiabatic Shear Mechanisms for the Hard Cutting Process
Institute of Scientific and Technical Information of China (English)
YUE Caixu; WANG Bo; LIU Xianli; FENG Huize; CAI Chunbin
2015-01-01
The most important consequence of adiabatic shear phenomenon is formation of sawtooth chip. Lots of scholars focused on the formation mechanism of sawtooth, and the research often depended on experimental approach. For the present, the mechanism of sawtooth chip formation still remalns some ambiguous aspects. This study develops a combined numerical and experimental approach to get deeper understanding of sawtooth chip formation mechanism for Polycrystalline Cubic Boron Nitride (PCBN) tools orthogonal cutting hard steel GCr15. By adopting the Johnson-Cook material constitutive equations, the FEM simulation model established in this research effectively overcomes serious element distortions and cell singularity in high straln domaln caused by large material deformation, and the adiabatic shear phenomenon is simulated successfully. Both the formation mechanism and process of sawtooth are simulated. Also, the change features regarding the cutting force as well as its effects on temperature are studied. More specifically, the contact of sawtooth formation frequency with cutting force fluctuation frequency is established. The cutting force and effect of cutting temperature on mechanism of adiabatic shear are investigated. Furthermore, the effects of the cutting condition on sawtooth chip formation are researched. The researching results show that cutting feed has the most important effect on sawtooth chip formation compared with cutting depth and speed. This research contributes a better understanding of mechanism, feature of chip formation in hard turning process, and supplies theoretical basis for the optimization of hard cutting process parameters.
Irreconcilable difference between quantum walks and adiabatic quantum computing
Wong, Thomas G.; Meyer, David A.
2016-06-01
Continuous-time quantum walks and adiabatic quantum evolution are two general techniques for quantum computing, both of which are described by Hamiltonians that govern their evolutions by Schrödinger's equation. In the former, the Hamiltonian is fixed, while in the latter, the Hamiltonian varies with time. As a result, their formulations of Grover's algorithm evolve differently through Hilbert space. We show that this difference is fundamental; they cannot be made to evolve along each other's path without introducing structure more powerful than the standard oracle for unstructured search. For an adiabatic quantum evolution to evolve like the quantum walk search algorithm, it must interpolate between three fixed Hamiltonians, one of which is complex and introduces structure that is stronger than the oracle for unstructured search. Conversely, for a quantum walk to evolve along the path of the adiabatic search algorithm, it must be a chiral quantum walk on a weighted, directed star graph with structure that is also stronger than the oracle for unstructured search. Thus, the two techniques, although similar in being described by Hamiltonians that govern their evolution, compute by fundamentally irreconcilable means.
Non-adiabatic molecular dynamics by accelerated semiclassical Monte Carlo
International Nuclear Information System (INIS)
Non-adiabatic dynamics, where systems non-radiatively transition between electronic states, plays a crucial role in many photo-physical processes, such as fluorescence, phosphorescence, and photoisomerization. Methods for the simulation of non-adiabatic dynamics are typically either numerically impractical, highly complex, or based on approximations which can result in failure for even simple systems. Recently, the Semiclassical Monte Carlo (SCMC) approach was developed in an attempt to combine the accuracy of rigorous semiclassical methods with the efficiency and simplicity of widely used surface hopping methods. However, while SCMC was found to be more efficient than other semiclassical methods, it is not yet as efficient as is needed to be used for large molecular systems. Here, we have developed two new methods: the accelerated-SCMC and the accelerated-SCMC with re-Gaussianization, which reduce the cost of the SCMC algorithm up to two orders of magnitude for certain systems. In many cases shown here, the new procedures are nearly as efficient as the commonly used surface hopping schemes, with little to no loss of accuracy. This implies that these modified SCMC algorithms will be of practical numerical solutions for simulating non-adiabatic dynamics in realistic molecular systems
Numerical study of polaron problem in the adiabatic limit
Marsiglio, Frank; Li, Zhou; Blois, Cindy; Baillie, Devin
2010-03-01
We study the polaron problem in a one dimensional chain and on a two dimensional square lattice. The models we have used are the Holstein model and the Su-Schrieffer-Heeger (SSH) model. By a variational procedure based on the Lanczos method, we are able to examine the polaron problem in the limit when the mass of the ion is very large, i.e. close to the adiabatic limit. It is known that for the Holstein model there is no phase transition [1] for any nonzero phonon energy. It is also known that for the one dimensional Holstein or SSH model there will be long range order [2] (e.g. dimerization) in the adiabatic limit at half-filling. It is then interesting to study the long range order on a two dimensional square lattice in and away from the adiabatic limit. Moreover, recent progress for the single polaron near an impurity (disorder) [3] make it an interesting problem for studying bond length disorder which can change the hopping energy in a specific direction in the Holstein model. Reference: [1] H. Lowen, Phys.Rev.B 37, 8661 (1988) [2] J.E.Hirsch and E. Frandkin, Phys. Rev. Lett. 49, 402 (1982) [3]A.S.Mishchenko et.al Phys.Rev.B 79(2009) 180301(R)
Dynamics of Quantum Adiabatic Evolution Algorithm for Number Partitioning
Smelyanskiy, Vadius; vonToussaint, Udo V.; Timucin, Dogan A.; Clancy, Daniel (Technical Monitor)
2002-01-01
We have developed a general technique to study the dynamics of the quantum adiabatic evolution algorithm applied to random combinatorial optimization problems in the asymptotic limit of large problem size n. We use as an example the NP-complete Number Partitioning problem and map the algorithm dynamics to that of an auxiliary quantum spin glass system with the slowly varying Hamiltonian. We use a Green function method to obtain the adiabatic eigenstates and the minimum exitation gap, gmin = O(n2(sup -n/2)), corresponding to the exponential complexity of the algorithm for Number Partitioning. The key element of the analysis is the conditional energy distribution computed for the set of all spin configurations generated from a given (ancestor) configuration by simultaneous flipping of a fixed number of spins. For the problem in question this distribution is shown to depend on the ancestor spin configuration only via a certain parameter related to the energy of the configuration. As the result, the algorithm dynamics can be described in terms of one-dimensional quantum diffusion in the energy space. This effect provides a general limitation of a quantum adiabatic computation in random optimization problems. Analytical results are in agreement with the numerical simulation of the algorithm.
Conditions for super-adiabatic droplet growth after entrainment mixing
Yang, Fan; Shaw, Raymond; Xue, Huiwen
2016-07-01
Cloud droplet response to entrainment and mixing between a cloud and its environment is considered, accounting for subsequent droplet growth during adiabatic ascent following a mixing event. The vertical profile for liquid water mixing ratio after a mixing event is derived analytically, allowing the reduction to be predicted from the mixing fraction and from the temperature and humidity for both the cloud and environment. It is derived for the limit of homogeneous mixing. The expression leads to a critical height above the mixing level: at the critical height the cloud droplet radius is the same for both mixed and unmixed parcels, and the critical height is independent of the updraft velocity and mixing fraction. Cloud droplets in a mixed parcel are larger than in an unmixed parcel above the critical height, which we refer to as the "super-adiabatic" growth region. Analytical results are confirmed with a bin microphysics cloud model. Using the model, we explore the effects of updraft velocity, aerosol source in the environmental air, and polydisperse cloud droplets. Results show that the mixed parcel is more likely to reach the super-adiabatic growth region when the environmental air is humid and clean. It is also confirmed that the analytical predictions are matched by the volume-mean cloud droplet radius for polydisperse size distributions. The findings have implications for the origin of large cloud droplets that may contribute to onset of collision-coalescence in warm clouds.
NMR implementation of adiabatic SAT algorithm using strongly modulated pulses.
Mitra, Avik; Mahesh, T S; Kumar, Anil
2008-03-28
NMR implementation of adiabatic algorithms face severe problems in homonuclear spin systems since the qubit selective pulses are long and during this period, evolution under the Hamiltonian and decoherence cause errors. The decoherence destroys the answer as it causes the final state to evolve to mixed state and in homonuclear systems, evolution under the internal Hamiltonian causes phase errors preventing the initial state to converge to the solution state. The resolution of these issues is necessary before one can proceed to implement an adiabatic algorithm in a large system where homonuclear coupled spins will become a necessity. In the present work, we demonstrate that by using "strongly modulated pulses" (SMPs) for the creation of interpolating Hamiltonian, one can circumvent both the problems and successfully implement the adiabatic SAT algorithm in a homonuclear three qubit system. This work also demonstrates that the SMPs tremendously reduce the time taken for the implementation of the algorithm, can overcome problems associated with decoherence, and will be the modality in future implementation of quantum information processing by NMR. PMID:18376911
Analysis of adiabatic transfer in cavity quantum electrodynamics
Indian Academy of Sciences (India)
Joyee Ghosh; R Ghosh; Deepak Kumar
2011-10-01
A three-level atom in a conﬁguration trapped in an optical cavity forms a basic unit in a number of proposed protocols for quantum information processing. This system allows for efﬁcient storage of cavity photons into long-lived atomic excitations, and their retrieval with high ﬁdelity, in an adiabatic transfer process through the ‘dark state’ by a slow variation of the control laser intensity. We study the full quantum mechanics of this transfer process with a view to examine the non-adiabatic effects arising from inevitable excitations of the system to states involving the upper level of , which is radiative. We ﬁnd that the ﬁdelity of storage is better, the stronger the control ﬁeld and the slower the rate of its switching off. On the contrary, unlike the adiabatic notion, retrieval is better with faster rates of switching on of an optimal control ﬁeld. Also, for retrieval, the behaviour with dissipation is non-monotonic. These results lend themselves to experimental tests. Our exact computations, when applied to slow variations of the control intensity for strong atom–photon couplings, are in very good agreement with Berry’s superadiabatic transfer results without dissipation.
Energy Technology Data Exchange (ETDEWEB)
Amendt, Peter, E-mail: amendt1@llnl.gov; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
2014-11-15
hindered inner-beam propagation, due largely to the confluence of rugby shape and low ray angles relative to the hohlraum symmetry axis. A significant inward pointing shift of 500 μm in the outer cones for the third (full energy) shot of the series was used to improve the inner-beam propagation, resulting in a nearly symmetric x-ray self-emission image of the compressed core and reduced sensitivity to mix. Comparatively low time-dependent symmetry swings were also measured, and a significantly lower hot electron fraction was measured for potentially favorable fuel adiabat control. The outer cone stimulated Brillouin scatter levels jumped significantly, but remedial measures such as the use of a boron dopant in the Au wall are planned. A continuing trend of delayed implosion times is found in rugby hohlraums, suggesting levels of unaccounted hohlraum energy (∼150–200 kJ) similar to what is inferred in cylinder hohlraums. A mix-based physical scenario is described, based on suppressed channel heat flux to the dense gold wall from a temperature-gradient reversal induced by a multispecies plasma lapse rate [P. Amendt, C. Bellei, and S. C. Wilks, Phys. Rev. Lett. 109, 075002 (2012)].
Amendt, Peter; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David
2014-11-01
inner-beam propagation, due largely to the confluence of rugby shape and low ray angles relative to the hohlraum symmetry axis. A significant inward pointing shift of 500 μm in the outer cones for the third (full energy) shot of the series was used to improve the inner-beam propagation, resulting in a nearly symmetric x-ray self-emission image of the compressed core and reduced sensitivity to mix. Comparatively low time-dependent symmetry swings were also measured, and a significantly lower hot electron fraction was measured for potentially favorable fuel adiabat control. The outer cone stimulated Brillouin scatter levels jumped significantly, but remedial measures such as the use of a boron dopant in the Au wall are planned. A continuing trend of delayed implosion times is found in rugby hohlraums, suggesting levels of unaccounted hohlraum energy (˜150-200 kJ) similar to what is inferred in cylinder hohlraums. A mix-based physical scenario is described, based on suppressed channel heat flux to the dense gold wall from a temperature-gradient reversal induced by a multispecies plasma lapse rate [P. Amendt, C. Bellei, and S. C. Wilks, Phys. Rev. Lett. 109, 075002 (2012)].
Hyperspectral data compression
Motta, Giovanni; Storer, James A
2006-01-01
Provides a survey of results in the field of compression of remote sensed 3D data, with a particular interest in hyperspectral imagery. This work covers topics such as compression architecture, lossless compression, lossy techniques, and more. It also describes a lossless algorithm based on vector quantization.
Hildebrand, Richard J.; Wozniak, John J.
2001-01-01
A compressed gas storage cell interconnecting manifold including a thermally activated pressure relief device, a manual safety shut-off valve, and a port for connecting the compressed gas storage cells to a motor vehicle power source and to a refueling adapter. The manifold is mechanically and pneumatically connected to a compressed gas storage cell by a bolt including a gas passage therein.
Microscale Regenerative Heat Exchanger
Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred
2006-01-01
The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.
Off-axis cooling of rotating devices using a crank-shaped heat pipe
Jankowski, Todd A.; Prenger, F. Coyne; Waynert, Joseph A.
2007-01-30
The present invention is a crank-shaped heat pipe for cooling rotating machinery and a corresponding method of manufacture. The crank-shaped heat pipe comprises a sealed cylindrical tube with an enclosed inner wick structure. The crank-shaped heat pipe includes a condenser section, an adiabatic section, and an evaporator section. The crank-shape is defined by a first curve and a second curve existing in the evaporator section or the adiabatic section of the heat pipe. A working fluid within the heat pipe provides the heat transfer mechanism.
Energy Technology Data Exchange (ETDEWEB)
Wei, Q., E-mail: qwei@uncc.edu [Department of Mechanical Engineering, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223-0001 (United States); Kecskes, L.J. [WMRD US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005 (United States); Ramesh, K.T. [Department of Mechanical Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
2013-08-20
In this work, we have investigated the effect of low-temperature rolling on the mechanical properties of commercial purity tungsten, particularly the high strain rate (dynamic) behavior of the cold-rolled samples vis-à-vis the as-received coarse-grained material. After rolling, the material was tested under both quasi-static and dynamic (Kolsky bar) uniaxial compression loading conditions. We have found that low-temperature rolling both improves the ductility and the strength of commercial purity tungsten. The rolled tungsten exhibits elastic-nearly perfectly plastic behavior under quasi-static loading, and a strong flow softening tendency with a precipitous stress drop under dynamic loading. Both in situ high speed movie snapshots and post-mortem examination of the dynamic samples suggest that the precipitous stress drop was caused by adiabatic shear banding in the cold-rolled material. The greatly enhanced susceptibility to adiabatic shear banding in the cold-rolled tungsten can either be explained semi-quantitatively based on a mechanistic model or from the rolling texture that leads to geometric softening under dynamic loading.
Radiative heat conduction and the magnetorotational instability
Araya-Gochez, R A; 10.1111/j.1365-2966.2004.08329.x
2004-01-01
A photon or a neutrino gas, semicontained by a non-diffusive particle species through scattering, comprises a rather peculiar magnetohydrodynamic fluid where the magnetic field is truly frozen only to the comoving volume associated with the mass density. Although radiative diffusion precludes a formal adiabatic treatment of compressive perturbations, we cast the energy equation in quasi- adiabatic form by assuming a negligible rate of energy exchange among species on the time-scale of the perturbation. This leads to a simplified dispersion relation for toroidal, non-axisymmetric magnetorotational modes when the accretion disc has comparable stress contributions from diffusive and non-diffusive components. The properties of the modes of fastest growth are shown to depend strongly on the compressibility of the mode, with a reduction in growth rate consistent with the results of Blaes & Socrates for axisymmetric modes. A clumpy disc structure is anticipated on the basis of the polarization properties of the ...
Heat pipes in modern heat exchangers
Energy Technology Data Exchange (ETDEWEB)
Vasiliev, L.L. [Academy of Science, Minsk (Russian Federation). A.V. Luikov Heat and Mass Transfer Institute
2005-01-01
Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 10{sup 3}-10{sup 5} W/m{sup 2} K, heat pipe thermal resistance is 0.01-0.03 K/W, therefore leading to smaller area and mass of heat exchangers. Miniature and micro heat pipes are welcomed for electronic components cooling and space two-phase thermal control systems. Loop heat pipes, pulsating heat pipes and sorption heat pipes are the novelty for modern heat exchangers. Heat pipe air preheaters are used in thermal power plants to preheat the secondary-primary air required for combustion of fuel in the boiler using the energy available in exhaust gases. Heat pipe solar collectors are promising for domestic use. This paper reviews mainly heat pipe developments in the Former Soviet Union Countries. Some new results obtained in USA and Europe are also included. (author)
Energy Technology Data Exchange (ETDEWEB)
Lottin, O.; Feidt, M.; Benelmir, R. [LEMTA-UHP Nancy-1, 54 - Vandoeuvre-les-Nancy (France)
1997-12-31
This paper is a series of transparencies presenting a comparative study of the thermal performances of different types of refrigerating machineries: di-thermal with vapor compression, tri-thermal with moto-compressor, with ejector, with free piston, adsorption-type, resorption-type, absorption-type, compression-absorption-type. A prototype of ammonia-water compression-absorption heat pump is presented and modeled. (J.S.)
Park, Joong-kyoo; Ro, Paul I.; He, Xiao; Mazzoleni, Andre P.
2014-01-01
An analysis and a proof‐of‐concept experiment of liquid‐piston compression were conducted for a table‐top Ocean Compressed Air Energy Storage (OCAES) prototype. A singlecylinder‐ type piston surrounded by water was modeled and analyzed based on convection heat transfer with fully developed internal flow, the assumption adopted by earlier liquid piston study in literature. Transient numerical results of this model were calculated for a polytropic compression with different polytropic index val...
Adiabatic quantum computing with spin qubits hosted by molecules.
Yamamoto, Satoru; Nakazawa, Shigeaki; Sugisaki, Kenji; Sato, Kazunobu; Toyota, Kazuo; Shiomi, Daisuke; Takui, Takeji
2015-01-28
A molecular spin quantum computer (MSQC) requires electron spin qubits, which pulse-based electron spin/magnetic resonance (ESR/MR) techniques can afford to manipulate for implementing quantum gate operations in open shell molecular entities. Importantly, nuclear spins, which are topologically connected, particularly in organic molecular spin systems, are client qubits, while electron spins play a role of bus qubits. Here, we introduce the implementation for an adiabatic quantum algorithm, suggesting the possible utilization of molecular spins with optimized spin structures for MSQCs. We exemplify the utilization of an adiabatic factorization problem of 21, compared with the corresponding nuclear magnetic resonance (NMR) case. Two molecular spins are selected: one is a molecular spin composed of three exchange-coupled electrons as electron-only qubits and the other an electron-bus qubit with two client nuclear spin qubits. Their electronic spin structures are well characterized in terms of the quantum mechanical behaviour in the spin Hamiltonian. The implementation of adiabatic quantum computing/computation (AQC) has, for the first time, been achieved by establishing ESR/MR pulse sequences for effective spin Hamiltonians in a fully controlled manner of spin manipulation. The conquered pulse sequences have been compared with the NMR experiments and shown much faster CPU times corresponding to the interaction strength between the spins. Significant differences are shown in rotational operations and pulse intervals for ESR/MR operations. As a result, we suggest the advantages and possible utilization of the time-evolution based AQC approach for molecular spin quantum computers and molecular spin quantum simulators underlain by sophisticated ESR/MR pulsed spin technology.
Performance Analysis of Vapour Compression Refrigeration System Utilizing Different Refrigerant
Ashish Patidar 1; Amitesh Paul
2014-01-01
The performance of heat transfer is one of the most important research areas in the field of thermal engineering. There are a large number of refrigerants, which are used to transfer heat from low temperature reservoir to high temperature reservoir by using vapour compression refrigeration system. This paper presents a performance analysis of vapour compression refrigeration system with using refrigerants like R-134a & Blend of R-290(propane) (50%) and R-600a (50% Isobutane). ...
Investigation of ejector re-compression absorption refrigeration cycle
Wu, Shenyi
1999-01-01
This thesis describes a theoretical and experimental investigation of the ejector re-compression lithium bromide absorption refrigeration cycle. In this novel cycle, a steam ejector is used to enhance the concentration process by compressing the vapour to a state that it can be used to re-heat the solution from where it was evolved. Since this cycle recovers the heat otherwise wasted in a conventional absorption cycle, the energy performance of the cycle is improved. The theoretical study sho...
Applications of Adiabatic Approximation to One- and Two-electron Phenomena in Strong Laser Fields
Bondar, Denys
2010-01-01
The adiabatic approximation is a natural approach for the description of phenomena induced by low frequency laser radiation because the ratio of the laser frequency to the characteristic frequency of an atom or a molecule is a small parameter. Since the main aim of this work is the study of ionization phenomena, the version of the adiabatic approximation that can account for the transition from a bound state to the continuum must be employed. Despite much work in this topic, a universally accepted adiabatic approach of bound-free transitions is lacking. Hence, based on Savichev's modified adiabatic approximation [Sov. Phys. JETP 73, 803 (1991)], we first of all derive the most convenient form of the adiabatic approximation for the problems at hand. Connections of the obtained result with the quasiclassical approximation and other previous investigations are discussed. Then, such an adiabatic approximation is applied to single-electron ionization and non-sequential double ionization of atoms in a strong low fr...
Nonlinear effects generation in non-adiabatically tapered fibres
Palací, Jesús; Mas, Sara; Monzón-Hernández, David; Martí, Javier
2015-12-01
Nonlinear effects are observed in a non-adiabatically tapered optical fibre. The designed structure allows for the introduction of self-phase modulation, which is observed through pulse breaking and spectral broadening, in approximately a centimetre of propagation using a commercial telecom laser. These devices are simple to fabricate and suitable to generate and control a variety of nonlinear effects in practical applications because they do not experience short-term degradation as previously reported approaches. Experimental and theoretical results are obtained, showing a good agreement.
Adiabatic regularisation of power spectra in nonminimally coupled chaotic inflation
Alinea, Allan L
2016-01-01
We investigate the effect of adiabatic regularisation on both the tensor- and scalar-perturbation power spectra in \\textit{nonminimally} coupled chaotic inflation. Similar to that of the \\textit{minimally} coupled general single-field inflation, we find that the subtraction term is suppressed by an exponentially decaying factor involving the number of $ e $-folds. By following the subtraction term long enough beyond horizon crossing, the regularised power spectrum tends to the "bare" power spectrum. This study justifies the use of the unregularised ("bare") power spectrum in standard calculations.
Adiabatic regularization of power spectra in nonminimally coupled chaotic inflation
Alinea, Allan L.
2016-10-01
We investigate the effect of adiabatic regularization on both the tensor- and scalar-perturbation power spectra in nonminimally coupled chaotic inflation. Similar to that of the minimally coupled general single-field inflation, we find that the subtraction term is suppressed by an exponentially decaying factor involving the number of e -folds. By following the subtraction term long enough beyond horizon crossing, the regularized power spectrum tends to the ``bare'' power spectrum. This study justifies the use of the unregularized (``bare'') power spectrum in standard calculations.
Stimulated Raman adiabatic passage analogues in classical physics
Energy Technology Data Exchange (ETDEWEB)
Rangelov, A A [University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel (Germany); Vitanov, N V [Department of Physics, Sofia University, James Bourchier 5 blvd., 1164 Sofia (Bulgaria); Shore, B W [618 Escondido Cir., Livermore, CA (United States)
2009-03-14
Stimulated Raman adiabatic passage (STIRAP) is a well-established technique for producing coherent population transfer in a three-state quantum system. We here exploit the resemblance between the Schroedinger equation for such a quantum system and the Newton equation of motion for a classical system undergoing torque to discuss several classical analogues of STIRAP, notably the motion of a moving charged particle subject to the Lorentz force of a quasistatic magnetic field, the orientation of a magnetic moment in a slowly varying magnetic field and the Coriolis effect. Like STIRAP, these phenomena occur for counterintuitive motion of the torque and are robustly insensitive to small changes in the interaction properties.
Analysis of interference in attosecond transient absorption in adiabatic condition
Dong, Wenpu; Wang, Xiaowei; Zhao, Zengxiu
2015-01-01
We simulate the transient absorption of attosecond pulses of infrared laser-dressed atoms by considering a three-level system with the adiabatic approximation. We study the delay-dependent interference features in the transient absorption spectra of helium atoms from the perspective of the coherent interaction processes between the attosecond pulse and the quasi-harmonics, and find that many features of the interference fringes in the absorption spectra of the attosecond pulse can be attributed to the coherence phase difference. And the modulation signals of laser-induced sidebands of the dark state is found related to the dark state with population modulated by the dressing field.
Simulation on refrigerant flow in adiabatic capillary tube
Institute of Scientific and Technical Information of China (English)
Meixia WANG; Cunfang LIU; Qiangtai ZHOU
2008-01-01
This paper proposes a new mathematical model to calculate flow characteristics of the adiabatic capillary tube, which is aimed at solving problems existing in some earlier models. The Stocker's model was modified with consideration of various effects due to sub-cooling, area concentration, and rolling diameter. The new model can be used not only for R22, but also for its substitutes such as R410A and R407C. A comparison of simulation results of the modified model with those in literature showed that the errors are within 10%. The flow charac-teristics are finally analyzed.
Relativistic blast waves in two dimensions. I - The adiabatic case
Shapiro, P. R.
1979-01-01
Approximate solutions are presented for the dynamical evolution of strong adiabatic relativistic blast waves which result from a point explosion in an ambient gas in which the density varies both with distance from the explosion center and with polar angle in axisymmetry. Solutions are analytical or quasi-analytical for the extreme relativistic case and numerical for the arbitrarily relativistic case. Some general properties of nonplanar relativistic shocks are also discussed, including the incoherence of spherical ultrarelativistic blast-wave fronts on angular scales greater than the reciprocal of the shock Lorentz factor, as well as the conditions for producing blast-wave acceleration.
From Classical Nonlinear Integrable Systems to Quantum Shortcuts to Adiabaticity
Okuyama, Manaka; Takahashi, Kazutaka
2016-08-01
Using shortcuts to adiabaticity, we solve the time-dependent Schrödinger equation that is reduced to a classical nonlinear integrable equation. For a given time-dependent Hamiltonian, the counterdiabatic term is introduced to prevent nonadiabatic transitions. Using the fact that the equation for the dynamical invariant is equivalent to the Lax equation in nonlinear integrable systems, we obtain the counterdiabatic term exactly. The counterdiabatic term is available when the corresponding Lax pair exists and the solvable systems are classified in a unified and systematic way. Multisoliton potentials obtained from the Korteweg-de Vries equation and isotropic X Y spin chains from the Toda equations are studied in detail.
Non-adiabatic study of the Kepler subgiant KIC 6442183
Directory of Open Access Journals (Sweden)
Grosjean M.
2015-01-01
Full Text Available Thanks to the precision of Kepler observations, [3] were able to measure the linewidth and amplitude of individual modes (including mixed modes in several subgiant power spectra. We perform a forward modelling of a Kepler subgiant based on surface properties and observed frequencies. Non-adiabatic computations including a time- dependent treatment of convection give the lifetimes of radial and non-radial modes. Next, combining the lifetimes and inertias with a stochastic excitation model gives the amplitudes of the modes. We can now directly compare theoretical and observed linewidths and amplitudes of mixed-modes to obtain new constraints on our theoretical models.
Fast CNOT gate via shortcuts to adiabatic passage
Wang, Zhe; Xia, Yan; Chen, Ye-Hong; Song, Jie
2016-10-01
Based on the shortcuts to adiabatic passage, we propose a scheme for directly implementing a controlled-not (CNOT) gate in a cavity quantum electrodynamics system. Moreover, we generalize the scheme to realize a CNOT gate in two separate cavities connected by an optical fiber. The strictly numerical simulation shows that the schemes are fast and insensitive to the decoherence caused by atomic spontaneous emission and photon leakage. In addition, the schemes can provide a theoretical basis for the manipulation of the multiqubit quantum gates in distant nodes of a quantum network.
Modeling of the Adiabatic and Isothermal Methanation Process
Porubova, Jekaterina; Bazbauers, Gatis; Markova, Darja
2011-01-01
Increased use of biomass offers one of the ways to reduce anthropogenic impact on the environment. Using various biomass conversion processes, it is possible to obtain different types of fuels: • solid, e.g. bio-carbon; • liquid, e.g. biodiesel and ethanol; • gaseous, e.g. biomethane. Biomethane can be used in the transport and energy sector, and the total methane production efficiency can reach 65%. By modeling adiabatic and isothermal methanation processes, the most effective one from the methane production point of view is defined. Influence of the process parameters on the overall efficiency of the methane production is determined.
Landau-Zener Transitions in an Adiabatic Quantum Computer
Johansson, J; Amin, M. H. S.; Berkley, A. J.; Bunyk, P.; Choi, V.; Harris, R.; Johnson, M. W.; Lanting, T. M.; Lloyd, Seth; ROSE, G
2008-01-01
We report an experimental measurement of Landau-Zener transitions on an individual flux qubit within a multi-qubit superconducting chip designed for adiabatic quantum computation. The method used isolates a single qubit, tunes its tunneling amplitude Delta into the limit where Delta is much less than both the temperature T and the decoherence-induced energy level broadening, and forces it to undergo a Landau-Zener transition. We find that the behavior of the qubit agrees to a high degree of a...
Adiabatic transport of qubits around a black hole
Viennot, David
2016-01-01
We consider localized qubits evolving around a black hole following a quantum adiabatic dynamics. We develop a geometric structure (based on fibre bundles) permitting to describe the quantum states of a qubit and the spacetime geometry in a single framework. The quantum decoherence induced by the black hole on the qubit is analysed in this framework (the role of the dynamical and geometric phases in this decoherence is treated), especially for the quantum teleportation protocol when one qubit falls to the event horizon. A simple formula to compute the fidelity of the teleportation is derived. The case of a Schwarzschild black hole is analysed.
Adiabatic quantum computation and quantum annealing theory and practice
McGeoch, Catherine C
2014-01-01
Adiabatic quantum computation (AQC) is an alternative to the better-known gate model of quantum computation. The two models are polynomially equivalent, but otherwise quite dissimilar: one property that distinguishes AQC from the gate model is its analog nature. Quantum annealing (QA) describes a type of heuristic search algorithm that can be implemented to run in the ``native instruction set'''' of an AQC platform. D-Wave Systems Inc. manufactures {quantum annealing processor chips} that exploit quantum properties to realize QA computations in hardware. The chips form the centerpiece of a nov
Compressed Sensing in Astronomy
Bobin, J; Ottensamer, R
2008-01-01
Recent advances in signal processing have focused on the use of sparse representations in various applications. A new field of interest based on sparsity has recently emerged: compressed sensing. This theory is a new sampling framework that provides an alternative to the well-known Shannon sampling theory. In this paper we investigate how compressed sensing (CS) can provide new insights into astronomical data compression and more generally how it paves the way for new conceptions in astronomical remote sensing. We first give a brief overview of the compressed sensing theory which provides very simple coding process with low computational cost, thus favoring its use for real-time applications often found on board space mission. We introduce a practical and effective recovery algorithm for decoding compressed data. In astronomy, physical prior information is often crucial for devising effective signal processing methods. We particularly point out that a CS-based compression scheme is flexible enough to account ...
Perturbation to Lie symmetry and another type of Hojman adiabatic invariants for Birkhoffian systems
Institute of Scientific and Technical Information of China (English)
Ding Ning; Fang Jian-Hui; Chen Xiang-Xia
2008-01-01
The perturbation to Lie symmetry and another type of Hojman adiabatic invariants induced from the perturbation to Lie symmetry for Birkhoffian systems are studied. The exact invariants of Lie symmetry for the system without perturbation are given. Based on the concept of adiabatic invariant, the perturbation to Lie symmetry is discussed and another new type of Hojman adiabatic invariants that have the different form from that in [Acta Phys. Sin. 55 3833] for the perturbed system are obtained.
Adiabatic heavy-ion fusion potentials for fusion at deep sub-barrier energies
Indian Academy of Sciences (India)
S V S Sastry; S Kailas; A K Mohanty; A Saxena
2005-01-01
The recently reported unusual behaviour of fusion cross-sections at extreme sub-barrier energies has been examined. The adiabatic limit of fusion barriers has been determined from experimental data using the barrier penetration model. These adiabatic barriers are consistent with the adiabatic fusion barriers derived from the modified Wilzynska–Wilzynski prescription. The fusion barrier systematics has been obtained for a wide range of heavy-ion systems.
Quantum pumping in closed systems, adiabatic transport, and the Kubo formula
Cohen, Doron
2003-01-01
Quantum pumping in closed systems is considered. We explain that the Kubo formula contains all the physically relevant ingredients for the calculation of the pumped charge ($Q$) within the framework of linear response theory. The relation to the common formulations of adiabatic transport and ``geometric magnetism" is clarified. We distinguish between adiabatic and dissipative contributions to $Q$. On the one hand we observe that adiabatic pumping does not have to be quantized. On the other ha...
Wójcik, P.; Zegrodnik, M.; Rzeszotarski, B.; Adamowski, J.
2016-09-01
The tunneling conductance through the half-metal/conical magnet/superconductor (HM/CM/SC) junctions is investigated with the use of the Bogoliubov-de Gennes equations in the framework of Blonder-Tinkham-Klapwijk formalism. Due to the spin band separation in the HM, the conductance in the subgap region is mainly determined by the anomalous Andreev reflection, the probability of which strongly depends on the spin transmission in the CM layer. We show that the spins of electrons injected from the HM can be transmitted through the CM to the SC either adiabatically or non-adiabatically depending on the period of the spatial modulation of the exchange field. We find that the conductance in the subgap region oscillates as a function of the CM layer thickness wherein the oscillations transform from the irregular pattern in the non-adiabatic regime to the regular one in the adiabatic regime. For both adiabatic and non-adiabatic transport regimes the conductance is studied over a broad range of parameters determining the spiral magnetization in the CM. We find that in the non-adiabatic regime, the decrease of the exchange field amplitude in the CM leads to the emergence of the conductance peak for the particular CM thickness in agreement with recent experiments.
Celiac Artery Compression Syndrome
Directory of Open Access Journals (Sweden)
Mohammed Muqeetadnan
2013-01-01
Full Text Available Celiac artery compression syndrome is a rare disorder characterized by episodic abdominal pain and weight loss. It is the result of external compression of celiac artery by the median arcuate ligament. We present a case of celiac artery compression syndrome in a 57-year-old male with severe postprandial abdominal pain and 30-pound weight loss. The patient eventually responded well to surgical division of the median arcuate ligament by laparoscopy.
Quasi-adiabatic vacuum-based column housing for very high-pressure liquid chromatography.
Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A
2016-07-22
A prototype vacuum-based (10(-6)Torr) column housing was built to thermally isolate the chromatographic column from the external air environment. The heat transfer mechanism is solely controlled by surface radiation, which was minimized by wrapping the column with low-emissivity aluminum tape. The adiabaticity of the column housing was quantitatively assessed from the measurement of the operational pressure and fluid temperature at the outlet of a 2.1mm×100mm column (sub-2 μm particles). The pressure drop along the column was raised up to 1kbar. The enthalpy balance of the eluent (water, acetonitrile, and one water/acetonitrile mixture, 70/30, v/v) showed that less than 1% of the viscous heat generated by friction of the fluid against the packed bed was lost to the external air environment. Such a vacuum-based column oven minimizes the amplitude of the radial temperature gradients across the column diameter and maximizes its resolving power.