Thermal Reservoir coupled to External Field and Quantum Dissipation
Patriarca, M; Patriarca, Fabrizio Illuminati & Marco
1992-01-01
In the framework of the Caldeira-Leggett model of dissipative quantum mechanics, we investigate the effects of the interaction of the thermal reservoir with an external field. In particular, we discuss how the interaction modifies the conservative dynamics of the central particle, and the mechanism of dissipation. We briefly comment on possible observable consequencies.
Nanoscale thermal imaging of dissipation in quantum systems
Halbertal, Dorri; Shalom, Moshe Ben; Embon, Lior; Shadmi, Nitzan; Anahory, Yonathan; Naren, HR; Sarkar, Jayanta; Uri, Aviram; Ronen, Yuval; Myasoedov, Yury; Levitov, Leonid; Joselevich, Ernesto; Geim, Andre Konstantin; Zeldov, Eli
2016-01-01
Energy dissipation is a fundamental process governing the dynamics of physical, chemical, and biological systems. It is also one of the main characteristics distinguishing quantum and classical phenomena. In condensed matter physics, in particular, scattering mechanisms, loss of quantum information, or breakdown of topological protection are deeply rooted in the intricate details of how and where the dissipation occurs. Despite its vital importance the microscopic behavior of a system is usually not formulated in terms of dissipation because the latter is not a readily measureable quantity on the microscale. Although nanoscale thermometry is gaining much recent interest, the existing thermal imaging methods lack the necessary sensitivity and are unsuitable for low temperature operation required for study of quantum systems. Here we report a superconducting quantum interference nano-thermometer device with sub 50 nm diameter that resides at the apex of a sharp pipette and provides scanning cryogenic thermal se...
Quantum chaos, thermalization and dissipation in nuclear systems
Indian Academy of Sciences (India)
Sudhir R Jain
2001-08-01
Nuclei have complex energy-level sequence with statistical properties in agreement with canonical random matrix theory. This agreement appears when the one-particle one-hole states are mixed completely with two-particle two-hole states. In the transition, there is a new universality which we present here, bringing about a relation between dynamics and statistics. We summarize also the role of chaos in thermalization and dissipation in isolated systems like nuclei. The methods used to bring forth this understanding emerge from random matrix theory, semiclassical physics, and the theory of dynamical systems.
Firearm suppressor having enhanced thermal management for rapid heat dissipation
Energy Technology Data Exchange (ETDEWEB)
Moss, William C.; Anderson, Andrew T.
2014-08-19
A suppressor is disclosed for use with a weapon having a barrel through which a bullet is fired. The suppressor has an inner portion having a bore extending coaxially therethrough. The inner portion is adapted to be secured to a distal end of the barrel. A plurality of axial flow segments project radially from the inner portion and form axial flow paths through which expanding propellant gasses discharged from the barrel flow through. The axial flow segments have radially extending wall portions that define sections which may be filled with thermally conductive material, which in one example is a thermally conductive foam. The conductive foam helps to dissipate heat deposited within the suppressor during firing of the weapon.
Dissipative Particle Dynamics investigation of parameters affecting planar nanochannel flows
Energy Technology Data Exchange (ETDEWEB)
Kasiteropoulou, D. [Hydromechanics and Environmental Engineering Laboratory, School of Engineering, University of Thessaly, 38834 Pedion Areos, Volos (Greece); Karakasidis, T.E., E-mail: thkarak@uth.gr [Hydromechanics and Environmental Engineering Laboratory, School of Engineering, University of Thessaly, 38834 Pedion Areos, Volos (Greece); Liakopoulos, A. [Hydromechanics and Environmental Engineering Laboratory, School of Engineering, University of Thessaly, 38834 Pedion Areos, Volos (Greece)
2011-11-25
The method of Dissipative Particle Dynamics is applied to investigate the effect of the parameters involved in a nano-channel Poisseuille flow. The parameters considered here include (a) fluid/wall interactions, (b) wall material, (c) range of interaction of fluid particles and wall particles, and (d) external applied force. The computed macroscopic quantities include density, velocity, pressure and temperature profiles. Fluid particle localization near the solid wall is affected by the conservative force (fluid/wall interactions), the wall number density, and the range of atomic interactions (cut-off radius). The external driving force magnitude does not affect the number density distribution. Fluid velocity increases as the conservative force and the wall density increase and the cut-off radius decreases. Pressure distribution is mainly affected by the conservative force and the interaction cut-off radius. Temperature is uniform across most of the channel but presents an increase close to the solid walls especially when increasing the external driving force. We believe that the detailed knowledge of the fluid behaviour under variation of the system parameters obtained from the DPD simulations could be helpful in the design of nanodevices such as lab-on-a-chip devices and nanomixers.
Thermal Convection in Granular Gases with Dissipative Lateral Walls
Pontuale, Giorgio; Gnoli, Andrea; Reyes, Francisco Vega; Puglisi, Andrea
2016-08-01
We consider a granular gas under the action of gravity, fluidized by a vibrating base. We show that a horizontal temperature gradient, here induced by limiting dissipative lateral walls (DLW), leads always to a granular thermal convection (DLW TC) that is essentially different from ordinary bulk-buoyancy-driven convection (BBD TC). In an experiment where BBD TC is inhibited, by reducing gravity with an inclined plane, we always observe a DLW TC cell next to each lateral wall. Such a cell squeezes towards the nearest wall as the gravity and/or the number of grains increase. Molecular dynamics simulations reproduce the experimental results and indicate that at large gravity or number of grains the DLW TC is barely detectable.
Dissipation process of binary gas mixtures in thermally relativistic flow
Yano, Ryosuke
2016-04-01
In this paper, dissipation process of binary gas mixtures in thermally relativistic flows is discussed with focus on characteristics of diffusion flux. As an analytical object, we consider the relativistic rarefied-shock layer around a triangular prism. Numerical results for the diffusion flux are compared with the Navier–Stokes–Fourier (NSF) order approximation of the diffusion flux, which is calculated using the diffusion and thermal-diffusion coefficients by Kox et al (1976 Physica A 84 165–74). In the case of uniform flow with small Lorentz contraction, the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is roughly approximated by the NSF order approximation inside the shock wave, whereas the diffusion flux in the vicinity of a wall is markedly different from the NSF order approximation. The magnitude of the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is similar to that of the NSF order approximation inside the shock wave, unlike the pressure deviator, dynamic pressure and heat flux, even when the Lorentz contraction in the uniform flow becomes large, because the diffusion flux does not depend on the generic Knudsen number from its definition in Eckart’s frame. Finally, the author concludes that for accuracy diffusion flux must be calculated using the particle four-flow and averaged four velocity, which are formulated using the four velocity defined by each species of hard spherical particles.
Dissipation process of binary mixture gas in thermally relativistic flow
Yano, Ryosuke
2016-01-01
In this paper, we discuss dissipation process of the binary mixture gas in the thermally relativistic flow \\textcolor{red}{by focusing on the characteristics of the diffusion flux}. As an analytical object, we consider the relativistic rarefied-shock layer problem around the triangle prism. Numerical results of the diffusion flux are compared with the Navier-Stokes-Fourier (NSF) order approximation of the diffusion flux, which is calculated using the diffusion and thermal-diffusion coefficients by Kox \\textit{et al}. [Physica A, 84, 1, pp.165-174 (1976)]. In the case of the uniform flow with the small Lorentz contraction, the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is roughly approximated by the NSF order approximation inside the shock wave, whereas the diffusion flux in the vicinity of the wall is markedly different from the NSF order approximation. The magnitude of the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is simil...
A very high cycle fatigue thermal dissipation investigation for titanium alloy TC4
Energy Technology Data Exchange (ETDEWEB)
Huang, Zhi Yong, E-mail: huangzy@scu.edu.cn [Sichuan University, School of Aeronautics and Astronautics, No. 29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Wang, Qing Yuan [Sichuan University, School of Aeronautics and Astronautics, No. 29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Wagner, Danièle; Bathias, Claude [Université ParisOuest Nanterre La Défense (France)
2014-04-01
Titanium alloy TC4 is widely used in aeronautics applications where it is subjected to high frequency fatigue loads. Tests are performed to investigate the alloy fatigue behavior sustaining ultrasonic fatigue load in Very High Cycle Fatigue (VHCF) regime. Thermal dissipation for the alloy in 20 kHz frequency is studied and a model is proposed to describe the temperature increment in the framework of thermodynamics by estimation of the anelastic and inelastic thermal dissipation at microscopic active sites in the reference element volume. The failure probability prediction method is used to evaluate the VHCF dispersion based on the two scale model and fatigue thermal dissipation analysis.
Tidal dissipation in creeping ice and the thermal evolution of Europa
McCarthy, Christine; Cooper, Reid F.
2016-06-01
The thermal and mechanical evolution of Europa and comparable icy satellites-the physics behind creating and sustaining a subsurface water ocean-depends almost entirely on the mechanical dissipation of tidal energy in ice to produce heat, the mechanism(s) of which remain poorly understood. In deformation experiments, we combine steady-state creep and low-frequency, small-strain periodic loading, similar conditions in which tectonics and tidal flexing are occurring simultaneously. The data reveal that the relevant, power-law attenuation in ice (i) is non-linear, depending on strain amplitude, (ii) is independent of grain size, and (iii) exceeds in absorption the prediction of the Maxwell solid model by an order of magnitude. The Maxwell solid model is widely used to model the dynamics of planetary ice shells, so this discrepancy is important. The prevalent understanding of damping in the geophysical context is that it is controlled by chemical diffusion on grain boundaries, which renders attenuation strongly dependent on grain size. In sharp contrast, our results indicate instead the importance of intracrystalline dislocations and their spatial interactions as the critical structural variable affecting dissipation. These dislocation structures are controlled by stress and realized by accumulated plastic strain. Thus, tectonics and attenuation are coupled, which, beyond the icy satellite/subsurface ocean problem, has implications also for understanding the attenuation of seismic waves in deforming regions of the Earth's upper mantle.
Estimating wave energy dissipation in the surf zone using thermal infrared imagery
Carini, Roxanne J.; Chickadel, C. Chris; Jessup, Andrew T.; Thomson, Jim
2015-06-01
Thermal infrared (IR) imagery is used to quantify the high spatial and temporal variability of dissipation due to wave breaking in the surf zone. The foam produced in an actively breaking crest, or wave roller, has a distinct signature in IR imagery. A retrieval algorithm is developed to detect breaking waves and extract wave roller length using measurements taken during the Surf Zone Optics 2010 experiment at Duck, NC. The remotely derived roller length and an in situ estimate of wave slope are used to estimate dissipation due to wave breaking by means of the wave-resolving model by Duncan (1981). The wave energy dissipation rate estimates show a pattern of increased breaking during low tide over a sand bar, consistent with in situ turbulent kinetic energy dissipation rate estimates from fixed and drifting instruments over the bar. When integrated over the surf zone width, these dissipation rate estimates account for 40-69% of the incoming wave energy flux. The Duncan (1981) estimates agree with those from a dissipation parameterization by Janssen and Battjes (2007), a wave energy dissipation model commonly applied within nearshore circulation models.
Generalized thermal resistance for convective heat transfer and its relation to entransy dissipation
Institute of Scientific and Technical Information of China (English)
CHEN Qun; REN JianXun
2008-01-01
In order to further analyze and optimize convective heat transfer process further, the concepts of heat flux weighted average heat temperature and heat flux weighted average heat temperature difference in multi-dimensional heat transfer system were introduced in this paper. The ratio of temperature difference to heat flux is defined as the generalized thermal resistance of convective heat transfer processes,and then the minimum thermal resistance theory for convective heat transfer optimization was developed. By analyzing the relationship between generalized thermal resistance and entansy dissipation in convective heat transfer processes, it can be concluded that the minimum thermal resistance theory equals the entransy dissipation extremum theory. Finally, a two-dimensional convective heat transfer process with constant wall temperature is taken as an example to illustrate the applicability of generalized thermal resistance to convective heat transfer process analysis and optimization.
How Does Satellite Dissipation Affect the Enceladus-Dione Mean-Motion Resonance?
Zhang, Ke; Nimmo, F.
2008-09-01
Tidal dissipation in a planet usually drives satellites outwards, often resulting in the satellites encountering mean-motion resonances. Because of precessions of the orbital node and pericenter, a single resonance splits into many individual resonances packed into a narrow region (see e.g. Murray and Dermott 1999). In the case of the 2:1 resonance between the Saturnian satellites Enceladus and Dione, the two satellites likely passed through two other strong nearby resonances that would affect their eccentricities before they were trapped into the current one (Meyer and Wisdom 2008). Here we investigate the orbital evolution of the two satellites during these resonant encounters with N-body simulations. In particular, we examine the effect of dissipation within the satellites, and conclude that this process significantly alters their orbital evolution. Recent observations strongly suggest that Enceladus is experiencing significant tidal dissipation at the present day (e.g. Spencer et al. 2006). Such dissipation is capable of circularizing the orbit on a relatively short timescale. Borderies (1984) showed that when resonant trapping is possible for two orbits, the capture probability decreases sharply when the relevant eccentricities are greater than some critical value. Because dissipation in a satellite acts to decrease its eccentricity, the probability of capture into resonance is increased for simulations in which satellite dissipation is included. For Enceladus and Dione, inclusion of satellite dissipation makes it difficult to avoid being trapped into a resonance encountered earlier than the currently observed one. Thus, the current resonance between the two satellites places strong constraints on their orbital evolution and tidal parameters, which in turn depends on their internal structures. We will present possible evolution scenarios for Enceladus and Dione; in particular, we will conclude that scenarios with a cold, ocean-free Dione are the most plausible.
Hot nuclei-Landau theory, thermal fluctuations and dissipation
International Nuclear Information System (INIS)
The basic ideas and theoretical methods used in the description of hot nuclei are reviewed. In particular, a macroscopic approach to shape transitions is discussed in the framework of the Landau theory in which the quadrupole shaps degress if freedom play the role of the order parameters. This theory describes the universal features of the nuclear shape evolution with temperature and spin. A unified description of fluctuations in all five quadrupole degress of freedom is introduced and plays an important role in the calculation of physical observables. A macroscopic approach to the giant dipole resonance (GDR) in hot nuclei is developed. With all parameters fixed by the zero temperature nuclear properties, the theory predicts both the GDR cross-section and angular anisotropy of the γ-rays in very good agreement with recent experiments. The intrinsic shape fluctuations are the main cause for the resonance broadening at higher temperatures, while the orientatin fluctuations are responsible for the observed attenuation in the angular anisotropy. Dissipation at finite temperature is discussed in the framework of a Langevin-like equation describing the time-dependent shape fluctuations. Non-adiabatic effects may cause motional narrowing of the resonance. (orig.)
Dissipative Bose-Einstein condensation in contact with a thermal reservoir
Caspar, S.; Hebenstreit, F.; Mesterházy, D.; Wiese, U.-J.
2016-07-01
We investigate the real-time dynamics of open quantum spin-1/2 or hardcore boson systems on a spatial lattice, which are governed by a Markovian quantum master equation. We derive general conditions under which the hierarchy of correlation functions closes such that their time evolution can be computed semi-analytically. Expanding our previous work (2016 Phys. Rev. A 93 021602) we demonstrate the universality of a purely dissipative quantum Markov process that drives the system of spin-1/2 particles into a totally symmetric superposition state, corresponding to a Bose-Einstein condensate of hardcore bosons. In particular, we show that the finite-size scaling behavior of the dissipative gap is independent of the chosen boundary conditions and the underlying lattice structure. In addition, we consider the effect of a uniform magnetic field as well as a coupling to a thermal bath to investigate the susceptibility of the engineered dissipative process to unitary and nonunitary perturbations. We establish the nonequilibrium steady-state phase diagram as a function of temperature and dissipative coupling strength. For a small number of particles N, we identify a parameter region in which the engineered symmetrizing dissipative process performs robustly, while in the thermodynamic limit N\\to ∞ , the coupling to the thermal bath destroys any long-range order.
Dissipative Bose–Einstein condensation in contact with a thermal reservoir
Caspar, S.; Hebenstreit, F.; Mesterházy, D.; Wiese, U.-J.
2016-07-01
We investigate the real-time dynamics of open quantum spin-1/2 or hardcore boson systems on a spatial lattice, which are governed by a Markovian quantum master equation. We derive general conditions under which the hierarchy of correlation functions closes such that their time evolution can be computed semi-analytically. Expanding our previous work (2016 Phys. Rev. A 93 021602) we demonstrate the universality of a purely dissipative quantum Markov process that drives the system of spin-1/2 particles into a totally symmetric superposition state, corresponding to a Bose–Einstein condensate of hardcore bosons. In particular, we show that the finite-size scaling behavior of the dissipative gap is independent of the chosen boundary conditions and the underlying lattice structure. In addition, we consider the effect of a uniform magnetic field as well as a coupling to a thermal bath to investigate the susceptibility of the engineered dissipative process to unitary and nonunitary perturbations. We establish the nonequilibrium steady-state phase diagram as a function of temperature and dissipative coupling strength. For a small number of particles N, we identify a parameter region in which the engineered symmetrizing dissipative process performs robustly, while in the thermodynamic limit N\\to ∞ , the coupling to the thermal bath destroys any long-range order.
Effect of enhanced thermal dissipation on the Rayleigh-Taylor instability in emulsion-like media
Energy Technology Data Exchange (ETDEWEB)
Toor, A.; Ryutov, D.
1997-07-01
Rayleigh-Taylor instability in a finely structured emulsion-like medium consisting of the two components of different compressibility is considered. Although the term ``emulsion`` is used to describe the structure of the medium, under typical fast Z-pinch conditions both components behave as gases. The two components are chosen in such a way that their densities in the unperturbed state are approximately equal. Specific emphasis has been made on the analysis of perturbations with the scale {lambda} considerably exceeding the size of the grains a. Averaged equations describing such perturbations am derived. The difference in compressibility of the two components leads to the formation of temperature variations at the scale a, and increases the rate of the thermal dissipation by a factor ({lambda}/a){sup 2}. The strongest stabilizing effect of the thermal dissipation takes place when the thermal relaxation time is comparable with the instability growth rate.
Daane, Abigail R.; McKagan, Sarah B.; Vokos, Stamatis; Scherr, Rachel E.
2015-06-01
Research has demonstrated that many students and some teachers do not consistently apply the conservation of energy principle when analyzing mechanical scenarios. In observing elementary and secondary teachers engaged in learning activities that require tracking and conserving energy, we find that challenges to energy conservation often arise in dissipative scenarios in which kinetic energy transforms into thermal energy (e.g., a ball rolls to a stop). We find that teachers expect that when they can see the motion associated with kinetic energy, they should be able to perceive the warmth associated with thermal energy. Their expectations are violated when the warmth produced is imperceptible. In these cases, teachers reject the idea that the kinetic energy transforms to thermal energy. Our observations suggest that apparent difficulties with energy conservation may have their roots in a strong and appropriate association between forms of energy and their perceptible indicators. We see teachers resolve these challenges by relating the original scenario to an exaggerated version in which the dissipated thermal energy is associated with perceptible warmth. Using these exaggerations, teachers infer that thermal energy is present to a lesser degree in the original scenario. They use this exaggeration strategy to track and conserve energy in dissipative scenarios.
Quantum fluctuations and thermal dissipation in higher derivative gravity
Roychowdhury, Dibakar
2015-01-01
In this paper, based on the $ AdS_{2}/CFT_{1} $ prescription, we explore the low frequency behavior of quantum two point functions for a special class of strongly coupled CFTs in one dimension whose dual gravitational counterpart consists of \\textit{extremal} black hole solutions in higher derivative theories of gravity defined over an asymptotically AdS space time. The quantum critical points thus described are supposed to correspond to a very large value of the dynamic exponent ($ z\\rightarrow \\infty $). In our analysis, we find that quantum fluctuations are enhanced due to the higher derivative corrections in the bulk which in turn increases the possibility of quantum phase transition near the critical point. On the field theory side, such higher derivative effects would stand for the corrections appearing due to the finite coupling in the gauge theory. Finally, we compute the coefficient of thermal diffusion at finite coupling corresponding to Gauss Bonnet corrected charged Lifshitz black holes in the bul...
Quantum fluctuations and thermal dissipation in higher derivative gravity
Directory of Open Access Journals (Sweden)
Dibakar Roychowdhury
2015-08-01
Full Text Available In this paper, based on the AdS2/CFT1 prescription, we explore the low frequency behavior of quantum two point functions for a special class of strongly coupled CFTs in one dimension whose dual gravitational counterpart consists of extremal black hole solutions in higher derivative theories of gravity defined over an asymptotically AdS spacetime. The quantum critical points thus described are supposed to correspond to a very large value of the dynamic exponent (z→∞. In our analysis, we find that quantum fluctuations are enhanced due to the higher derivative corrections in the bulk which in turn increases the possibility of quantum phase transition near the critical point. On the field theory side, such higher derivative effects would stand for the corrections appearing due to the finite coupling in the gauge theory. Finally, we compute the coefficient of thermal diffusion at finite coupling corresponding to Gauss Bonnet corrected charged Lifshitz black holes in the bulk. We observe an important crossover corresponding to z=5 fixed point.
Entransy dissipation-based constraint for optimization of heat exchanger networks in thermal systems
International Nuclear Information System (INIS)
The Lagrange multiplier method is introduced for the global optimization of HENs (heat exchanger networks) with fixed layouts to give the optimal configuration of thermal systems that cannot be determined by other methods, such as HEN synthesis or linear programming method. A four-loop HEN with five heat exchangers and heat exchangers in thermodynamic systems are optimized as two examples from different perspectives. The first perspective is based on energy conservation where the energy and heat transfer equations act as the constraints in the Lagrange function. The second perspective is the heat transfer irreversibility where the entransy dissipation-based equation acts as the constraint. The entransy dissipation-based constraint eliminates the number of unknown intermediate fluid temperatures in the HENs and the corresponding number of constraints for HENs in thermal systems, which greatly simplifies the solution of optimization equations. Although the entropy generation-based equation can also act as a constraint, the intermediate fluid temperatures in the HENs cannot be eliminated because the entropy generation is a function of the absolute fluid temperature. As a result, the number of constraints is the same as when using energy conservation, so the optimization procedure for multi-component thermal systems cannot be simplified. - Highlights: • Lagrange multiplier method is a good option in thermal system optimization. • Entransy balance equation acts as a constraint without intermediate temperatures. • Entransy dissipation-based method greatly simplifies the optimization. • Entransy method is superior to traditional and entropy methods in some cases
Hu Jianjun; Li Tao; Li Jing
2014-01-01
Aimed to achieve good thermal stability of lithium batteries in electric vehicles under the conditions of high-power. This study established a three-dimensional, transient heat dissipation model for Lithium-ion battery package in the three-dimensional Cartesian coordinate system based on theoretical knowledge of thermodynamics and heat transfer. With the help of the numerical simulation theoretical of CFD, the flow and temperature field of force air cooling Lithium-ion battery pack was simula...
Lei, Huan; Baker, Nathan A.; Wu, Lei; Schenter, Gregory K.; Mundy, Christopher J.; Tartakovsky, Alexandre M.
2016-08-01
Thermal fluctuations cause perturbations of fluid-fluid interfaces and highly nonlinear hydrodynamics in multiphase flows. In this work, we develop a multiphase smoothed dissipative particle dynamics (SDPD) model. This model accounts for both bulk hydrodynamics and interfacial fluctuations. Interfacial surface tension is modeled by imposing a pairwise force between SDPD particles. We show that the relationship between the model parameters and surface tension, previously derived under the assumption of zero thermal fluctuation, is accurate for fluid systems at low temperature but overestimates the surface tension for intermediate and large thermal fluctuations. To analyze the effect of thermal fluctuations on surface tension, we construct a coarse-grained Euler lattice model based on the mean field theory and derive a semianalytical formula to directly relate the surface tension to model parameters for a wide range of temperatures and model resolutions. We demonstrate that the present method correctly models dynamic processes, such as bubble coalescence and capillary spectra across the interface.
Directory of Open Access Journals (Sweden)
Hu Jianjun
2014-01-01
Full Text Available Aimed to achieve good thermal stability of lithium batteries in electric vehicles under the conditions of high-power. This study established a three-dimensional, transient heat dissipation model for Lithium-ion battery package in the three-dimensional Cartesian coordinate system based on theoretical knowledge of thermodynamics and heat transfer. With the help of the numerical simulation theoretical of CFD, the flow and temperature field of force air cooling Lithium-ion battery pack was simulated with the heat source obtained from dynamic performance simulations of Pure Electric Vehicles (PEVs under 15% climbing conditions. For the issues of high temperature rise and large temperature difference, optimal programs to improve the cooling effect of Lithium-ion battery pack were proposed. Simulation results indicate that the optimal measures make heat dissipation well and temperature distribution uniform, which satisfies the application requirement in PEVs.
Daane, Abigail R; Vokos, Stamatis; Scherr, Rachel E
2014-01-01
Research has demonstrated that many students and some teachers do not consistently apply the conservation of energy principle when analyzing mechanical scenarios. In observing elementary and secondary teachers engaged in learning activities that require tracking and conserving energy, we find that challenges to energy conservation often arise in dissipative scenarios in which kinetic energy transforms into thermal energy (e.g., a ball rolls to a stop). We find that teachers expect that when they can see the motion associated with kinetic energy, they should be able to perceive the warmth associated with thermal energy. Their expectations are violated when the warmth produced is imperceptible. In these cases, teachers reject the idea that the kinetic energy transforms to thermal energy. Our observations suggest that apparent difficulties with energy conservation may have their roots in a strong and productive association between forms of energy and their perceptible indicators. We see teachers resolve these ch...
Thermal Dissipation Modelling and Design of ITER PF Converter Alternating Current Busbar
Guo, Bin; Song, Zhiquan; Fu, Peng; Jiang, Li; Li, Jinchao; Wang, Min; Dong, Lin
2016-10-01
Because the larger metallic surrounds are heated by the eddy current, which is generated by the AC current flowing through the AC busbar in the International Thermonuclear Experimental Reactor (ITER) poloidal field (PF) converter system, shielding of the AC busbar is required to decrease the temperature rise of the surrounds to satisfy the design requirement. Three special types of AC busbar with natural cooling, air cooling and water cooling busbar structure have been proposed and investigated in this paper. For each cooling scheme, a 3D finite model based on the proposed structure has been developed to perform the electromagnetic and thermal analysis to predict their operation behavior. Comparing the analysis results of the three different cooling patterns, water cooling has more advantages than the other patterns and it is selected to be the thermal dissipation pattern for the AC busbar of ITER PF converter unit. The approach to qualify the suitable cooling scheme in this paper can be provided as a reference on the thermal dissipation design of AC busbar in the converter system. supported by National Natural Science Foundation of China (No. 51407179)
Heber, Ulrich; Soni, Vineet; Strasser, Reto J
2011-05-01
During desiccation, fluorescence emission and stable light-dependent charge separation in the reaction centers (RCs) of photosystem II (PSII) declined strongly in three different lichens: in Parmelia sulcata with an alga as the photobiont, in Peltigera neckeri with a cyanobacterium and in the tripartite lichen Lobaria pulmonaria. Most of the decline of fluorescence was caused by a decrease in the quantum efficiency of fluorescence emission. It indicated the activation of photoprotective thermal energy dissipation. Photochemical activity of the RCs was retained even after complete desiccation. It led to light-dependent absorption changes and found expression in reversible increases in fluorescence or in fluorescence quenching. Lowering the temperature changed the direction of fluorescence responses in P. sulcata. The observations are interpreted to show that reversible light-induced increases in fluorescence emission in desiccated lichens indicate the functionality of the RCs of PSII. Photoprotection is achieved by the drainage of light energy to dissipating centers outside the RCs before stable charge separation can take place. Reversible quenching of fluorescence by strong illumination is suggested to indicate the conversion of the RCs from energy conserving to energy dissipating units. This permits them to avoid photoinactivation. On hydration, re-conversion occurs to energy-conserving RCs. PMID:21029105
On the viscous dissipation modeling of thermal fluid flow in a porous medium
Salama, Amgad
2011-02-24
The problem of viscous dissipation and thermal dispersion in saturated porous medium is numerically investigated for the case of non-Darcy flow regime. The fluid is induced to flow upward by natural convection as a result of a semi-infinite vertical wall that is immersed in the porous medium and is kept at constant higher temperature. The boundary layer approximations were used to simplify the set of the governing, nonlinear partial differential equations, which were then non-dimensionalized and solved using the finite elements method. The results for the details of the governing parameters are presented and investigated. It is found that the irreversible process of transforming the kinetic energy of the moving fluid to heat energy via the viscosity of the moving fluid (i.e.; viscous dissipation) resulted in insignificant generation of heat for the range of parameters considered in this study. On the other hand, thermal dispersion has shown to disperse heat energy normal to the wall more effectively compared with the normal diffusion mechanism. © 2011 Springer-Verlag.
Heber, Ulrich
2008-09-01
In order to survive sunlight in the absence of water, desiccation-tolerant green plants need to be protected against photooxidation. During drying of the chlorolichen Cladonia rangiformis and the cyanolichen Peltigera neckeri, chlorophyll fluorescence decreased and stable light-dependent charge separation in reaction centers of the photosynthetic apparatus was lost. The presence of light during desiccation increased loss of fluorescence in the chlorolichen more than that in the cyanolichen. Heating of desiccated Cladonia thalli, but not of Peltigera thalli, increased fluorescence emission more after the lichen had been dried in the light than after drying in darkness. Activation of zeaxanthin-dependent energy dissipation by protonation of the PsbS protein of thylakoid membranes was not responsible for the increased loss of chlorophyll fluorescence by the chlorolichen during drying in the light. Glutaraldehyde inhibited loss of chlorophyll fluorescence during drying. Desiccation-induced loss of chlorophyll fluorescence and of light-dependent charge separation are interpreted to indicate activation of a highly effective mechanism of photoprotection in the lichens. Activation is based on desiccation-induced conformational changes of a pigment-protein complex. Absorbed light energy is converted into heat within a picosecond or femtosecond time domain. When present during desiccation, light interacts with the structural changes of the protein providing increased photoprotection. Energy dissipation is inactivated and structural changes are reversed when water becomes available again. Reversibility of ultra-fast thermal dissipation of light energy avoids photo-damage in the absence of water and facilitates the use of light for photosynthesis almost as soon as water becomes available. PMID:18587600
On the sound attenuation in fluid due to the thermal diffusion and viscous dissipation
International Nuclear Information System (INIS)
We review the sound attenuation in fluid due to the thermal diffusion and viscous dissipation and derive the formula of the sound attenuation coefficient in fluid by solving a fully thermally–mechanically coupled equation set. Problem occurring in Stokes–Kirchhoff relation, the well-known and widely used classical formula for sound attenuation coefficient, is therefore found and pointed out. The reason for its generation is analyzed and verified. An improved formula to replace Stokes–Kirchhoff relation is suggested and the typical case for the error in calculating sound pressure level (SPL) of attenuated sound wave in fluid between the two formulas is also given. - Highlights: • Problem with Stokes–Kirchhoff relation. • Generation reason of defect in Stokes–Kirchhoff relation. • An improved formula for sound attenuation coefficient in fluid. • Typical cases of the calculation error by Stokes–Kirchhoff relation
[Application of thermal dissipation probe in the study of Bambusa chungii sap flow].
Zhao, Ping; Mei, Ting-Ting; Ni, Guang-Yan; Yu, Meng-Hao; Zeng, Xiao-Ping
2012-04-01
Based on the validation of Granier's empirical formula for calculating tree stem sap flux density, a comparative study was conducted on the measurement of Bambusa chungi sap flow by using different lengths of thermal dissipation probe (TDP), aimed to approach the applicability of TDP in measuring the sap flow of B. chungii. The difference in the daily change of the sap flow between B. chungii and nearby growing Schima superb was also analyzed. Because of the thinner bamboo wall and the heterogeneous anatomy, the sap flux density of B. chungii measured by 10 mm long probe could be underestimated, but that measured by 8 and 5 mm long probes could be relatively accurate. The comparison of the sap flow between B. chungii and nearby growing S. superba revealed that both the mean sap flux density and its daily change pattern' s skewness of B. chungii were higher than those of S. superba, but the nighttime sap flow of B. chungii was less than that of S. superba, indicating that the water recharge of B. chungii during nighttime was less active than that of S. superba. It was suggested that using TDP to investigate the sap flow of bamboo would be feasible, but careful calibration would be required before the TDP was put into application on different bamboo species.
International Nuclear Information System (INIS)
The thermal development of the hydrodynamically developing laminar flow of a viscoplastic fluid (fluid of Bingham) between two plane plates maintained at a constant temperature has been studied numerically. This analysis has shown the effect caused by inertia and the rheological behaviour of the fluid on the velocity, pressure and temperature fields. The effects of Bingham and Peclet numbers on the Nusselt values with the inclusion of viscous dissipation are also discussed. (authors)
Energy Technology Data Exchange (ETDEWEB)
Boualit, A.; Boualit, S. [Unite de recherche appliquee en energies renouvelables, Ghardaia (Algeria); Zeraibi, N. [Universite de Boumerdes, Faculte des hydrocarbures dept. Transport et equipement, Boumerdes (Algeria); Amoura, M. [Universite des Sciences et de la Technologie Houari Boumedienne, Faculte de Physique, Dept. Energetique, Alger (Algeria)
2011-01-15
The thermal development of the hydrodynamically developing laminar flow of a viscoplastic fluid (fluid of Bingham) between two plane plates maintained at a constant temperature has been studied numerically. This analysis has shown the effect caused by inertia and the rheological behaviour of the fluid on the velocity, pressure and temperature fields. The effects of Bingham and Peclet numbers on the Nusselt values with the inclusion of viscous dissipation are also discussed. (authors)
Cating, Emma E M; Pinion, Christopher W; Van Goethem, Erika M; Gabriel, Michelle M; Cahoon, James F; Papanikolas, John M
2016-01-13
Thermal management is an important consideration for most nanoelectronic devices, and an understanding of the thermal conductivity of individual device components is critical for the design of thermally efficient systems. However, it can be difficult to directly probe local changes in thermal conductivity within a nanoscale system. Here, we utilize the time-resolved and diffraction-limited imaging capabilities of ultrafast pump-probe microscopy to determine, in a contact-free configuration, the local thermal conductivity in individual Si nanowires (NWs). By suspending single NWs across microfabricated trenches in a quartz substrate, the properties of the same NW both on and off the substrate are directly compared. We find the substrate has no effect on the recombination lifetime or diffusion length of photogenerated charge carriers; however, it significantly impacts the thermal relaxation properties of the NW. In substrate-supported regions, thermal energy deposited into the lattice by the ultrafast laser pulse dissipates within ∼10 ns through thermal diffusion and coupling to the substrate. In suspended regions, the thermal energy persists for over 100 ns, and we directly image the time-resolved spatial motion of the thermal signal. Quantitative analysis of the transient images permits direct determination of the NW's local thermal conductivity, which we find to be a factor of ∼4 smaller than in bulk Si. Our results point to the strong potential of pump-probe microscopy to be used as an all-optical method to quantify the effects of localized environment and morphology on the thermal transport characteristics of individual nanostructured components. PMID:26629610
Institute of Scientific and Technical Information of China (English)
Kamel Hooman; Alireza Pourshaghaghy; Arash Ejlali
2006-01-01
The viscous dissipation effect on forced convection in a porous saturated circular tube with an isoflux wall is investigated on the basis of the Brinkman flow model.For the thermally developing region, a numerical study is reported while a perturbation analysis is presented to find expressions for the temperature profile and the Nusselt number for the fully developed region. The fully developed Nusselt number found by numerical solution for the developing region is compared with that of asymptotic analysis and a good degree of agreement is observed.
How does dissipation affect the transition from static to dynamic macroscopic friction?
Gershenzon, Naum I; Skinner, Thomas
2014-01-01
Description of the transitional process from a static to a dynamic frictional regime is a fundamental problem of modern physics. Previously we developed a model based on the well-known Frenkel-Kontorova model to describe dry macroscopic friction. Here this model has been modified to include the effect of dissipation in derived relations between the kinematic and dynamic parameters of a transition process. The main (somewhat counterintuitive) result is a demonstration that the rupture (i.e. detachment front) velocity of the slip pulse which arises during the transition does not depend on friction. The only parameter (besides the elastic and plastic properties of the medium) controlling the rupture velocity is the spatial distribution of the shear to normal stress ratio. In contrast to the rupture velocity, the slip velocity does depend on friction. The model we have developed describes these processes over a wide range of rupture and slip velocities (up to 7 orders of magnitude) allowing, in particular, the co...
Motsumi, T. G.; Makinde, O. D.
2012-10-01
The effects of suction, viscous dissipation, thermal radiation and thermal diffusion are numerically studied on a boundary layer flow of nanofluids over a moving flat plate. The partial differential equations governing the motion are transformed into ordinary differential equations using similarity solutions, and are solved using the Runge-Kutta-Fehlberg method with the shooting technique. The effects of nanoparticle volume fraction, the type of nanoparticles, the radiation parameter, the Brinkman number, the suction/injection parameter and the relative motion of the plate on the nanofluids velocity, temperature, skin friction and heat transfer characteristics are graphically presented and then discussed quantitatively. A comparative study between the previously published and the present results in a limiting sense reveals excellent agreement between them.
García-Jaramillo, M; Redondo-Gómez, S; Barcia-Piedras, J M; Aguilar, M; Jurado, V; Hermosín, M C; Cox, L
2016-04-15
The presence of pesticides in surface and groundwater has grown considerably in the last decades as a consequence of the intensive farming activity. Several studies have shown the benefits of using organic amendments to prevent losses of pesticides from runoff or leaching. A particular soil from the Guadalquivir valley was placed in open air ponds and amended at 1 or 2% (w/w) with alperujo compost (AC), a byproduct from the olive oil industry. Tricyclazole dissipation, rice growth and microbial diversity were monitored along an entire rice growing season. An increase in the net photosynthetic rate of Oryza sativa plants grown in the ponds with AC was observed. These plants produced between 1100 and 1300kgha(-1) more rice than plants from the unamended ponds. No significant differences were observed in tricyclazole dissipation, monitored for a month in soil, surface and drainage water, between the amended and unamended ponds. The structure and diversity of bacteria and fungi communities were also studied by the use of the polymerase chain reaction denaturing gel electrophoresis (PCR-DGGE) from DNA extracted directly from soil samples. The banding pattern was similar for all treatments, although the density of bands varied throughout the time. Apparently, tricyclazole did not affect the structure and diversity of bacteria and fungi communities, and this was attributed to its low bioavailability. Rice cultivation under paddy field conditions may be more efficient under the effects of this compost, due to its positive effects on soil properties, rice yield, and soil microbial diversity.
Wullschleger, Stan D; Childs, Kenneth W; King, Anthony W; Hanson, Paul J
2011-06-01
A variety of thermal approaches are used to estimate sap flux density in stems of woody plants. Models have proved valuable tools for interpreting the behavior of heat pulse, heat balance and heat field deformation techniques, but have seldom been used to describe heat transfer dynamics for the heat dissipation method. Therefore, to better understand the behavior of heat dissipation probes, a model was developed that takes into account the thermal properties of wood, the physical dimensions and thermal characteristics of the probes, and the conductive and convective heat transfer that occurs due to water flow in the sapwood. Probes were simulated as aluminum tubes 20 mm in length and 2 mm in diameter, whereas sapwood, heartwood and bark each had a density and water fraction that determined their thermal properties. Base simulations assumed a constant sap flux density with sapwood depth and no wounding or physical disruption of xylem beyond the 2 mm diameter hole drilled for probe installation. Simulations across a range of sap flux densities showed that the dimensionless quantity k [defined as (ΔT(m) -ΔT)/ΔT, where ΔT(m) is the temperature differential (ΔT) between the heated and unheated probe under zero-flow conditions] was dependent on the thermal conductivity of the sapwood. The relationship between sap flux density and k was also sensitive to radial gradients in sap flux density and to xylem disruption near the probe. Monte Carlo analysis in which 1000 simulations were conducted while simultaneously varying thermal conductivity and wound diameter revealed that sap flux density and k showed considerable departure from the original calibration equation used with this technique. The departure was greatest for variation in sap flux density typical of ring-porous species. Depending on the specific combination of thermal conductivity and wound diameter, use of the original calibration equation resulted in an 81% under- to 48% overestimation of sap flux density
Strong Tidal Dissipation in Saturn and Constraints on Enceladus' Thermal State from Astrometry
Lainey, Valéry; Karatekin, Özgür; Desmars, Josselin; Charnoz, Sébastien; Arlot, Jean-Eudes; Emelyanov, Nicolai; Le Poncin-Lafitte, Christophe; Mathis, Stéphane; Remus, Françoise; Tobie, Gabriel; Zahn, Jean-Paul
2012-06-01
Tidal interactions between Saturn and its satellites play a crucial role in both the orbital migration of the satellites and the heating of their interiors. Therefore, constraining the tidal dissipation of Saturn (here the ratio k 2/Q) opens the door to the past evolution of the whole system. If Saturn's tidal ratio can be determined at different frequencies, it may also be possible to constrain the giant planet's interior structure, which is still uncertain. Here, we try to determine Saturn's tidal ratio through its current effect on the orbits of the main moons, using astrometric data spanning more than a century. We find an intense tidal dissipation (k 2/Q = (2.3 ± 0.7) × 10-4), which is about 10 times higher than the usual value estimated from theoretical arguments. As a consequence, eccentricity equilibrium for Enceladus can now account for the huge heat emitted from Enceladus' south pole. Moreover, the measured k 2/Q is found to be poorly sensitive to the tidal frequency, on the short frequency interval considered. This suggests that Saturn's dissipation may not be controlled by turbulent friction in the fluid envelope as commonly believed. If correct, the large tidal expansion of the moon orbits due to this strong Saturnian dissipation would be inconsistent with the moon formations 4.5 Byr ago above the synchronous orbit in the Saturnian subnebulae. But it would be compatible with a new model of satellite formation in which the Saturnian satellites formed possibly over a longer timescale at the outer edge of the main rings. In an attempt to take into account possible significant torques exerted by the rings on Mimas, we fitted a constant rate da/dt on Mimas' semi-major axis as well. We obtained an unexpected large acceleration related to a negative value of da/dt = -(15.7 ± 4.4) × 10-15 AU day-1. Such acceleration is about an order of magnitude larger than the tidal deceleration rates observed for the other moons. If not coming from an astrometric
STRONG TIDAL DISSIPATION IN SATURN AND CONSTRAINTS ON ENCELADUS' THERMAL STATE FROM ASTROMETRY
Energy Technology Data Exchange (ETDEWEB)
Lainey, Valery; Desmars, Josselin; Arlot, Jean-Eudes; Emelyanov, Nicolai; Remus, Francoise [IMCCE-Observatoire de Paris, UMR 8028 du CNRS, UPMC, 77 Av. Denfert-Rochereau, 75014 Paris (France); Karatekin, Oezguer [Royal Observatory of Belgium, Avenue Circulaire 3, 1180 Uccle, Bruxelles (Belgium); Charnoz, Sebastien; Mathis, Stephane [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/SAp Centre de Saclay, 91191 Gif-sur-Yvette (France); Le Poncin-Lafitte, Christophe [SyRTE-Observatoire de Paris, UMR 8630 du CNRS, 77 Av. Denfert-Rochereau, 75014 Paris (France); Tobie, Gabriel [Laboratoire de Planetologie et Geodynamique de Nantes, Universite de Nantes, CNRS, UMR 6112, 2 rue de la Houssiniere, 44322 Nantes Cedex 3 (France); Zahn, Jean-Paul, E-mail: lainey@imcce.fr [LUTH-Observatoire de Paris, UMR 8102 du CNRS, 5 place Jules Janssen, 92195 Meudon Cedex (France)
2012-06-10
Tidal interactions between Saturn and its satellites play a crucial role in both the orbital migration of the satellites and the heating of their interiors. Therefore, constraining the tidal dissipation of Saturn (here the ratio k{sub 2}/Q) opens the door to the past evolution of the whole system. If Saturn's tidal ratio can be determined at different frequencies, it may also be possible to constrain the giant planet's interior structure, which is still uncertain. Here, we try to determine Saturn's tidal ratio through its current effect on the orbits of the main moons, using astrometric data spanning more than a century. We find an intense tidal dissipation (k{sub 2}/Q = (2.3 {+-} 0.7) Multiplication-Sign 10{sup -4}), which is about 10 times higher than the usual value estimated from theoretical arguments. As a consequence, eccentricity equilibrium for Enceladus can now account for the huge heat emitted from Enceladus' south pole. Moreover, the measured k{sub 2}/Q is found to be poorly sensitive to the tidal frequency, on the short frequency interval considered. This suggests that Saturn's dissipation may not be controlled by turbulent friction in the fluid envelope as commonly believed. If correct, the large tidal expansion of the moon orbits due to this strong Saturnian dissipation would be inconsistent with the moon formations 4.5 Byr ago above the synchronous orbit in the Saturnian subnebulae. But it would be compatible with a new model of satellite formation in which the Saturnian satellites formed possibly over a longer timescale at the outer edge of the main rings. In an attempt to take into account possible significant torques exerted by the rings on Mimas, we fitted a constant rate da/dt on Mimas' semi-major axis as well. We obtained an unexpected large acceleration related to a negative value of da/dt = -(15.7 {+-} 4.4) Multiplication-Sign 10{sup -15} AU day{sup -1}. Such acceleration is about an order of magnitude larger
Institute of Scientific and Technical Information of China (English)
Chen Liang; Zhang Wan-Rong; Jin Dong-Yue; Shen Pei; Xie Hong-Yun; Ding Chun-Bao; Xiaa Ying; Sun Bo-Tao; Wang Ren-Qing
2011-01-01
method of non-uniform finger spacing is proposed to enhance thermal stability of a multiple finger power SiGe hererojunction bipolar transistor under different power dissipations. Temperature distribution on the emitter fingers of a multi-finger SiGe heterojunction bipolar transistor is studied using a numerical electro-thermal model. The results show that the SiGe heterojunction bipolar transistor with non-uniform finger spacing has a small temperature difference between fingers compared with a traditional uniform finger spacing heterojunction bipolar transistor at the same power dissipation. What is most important is that the ability to improve temperature non-uniformity is not weakened as power dissipation increases. So the method of non-uniform finger spacing is very effective in enhancing the thermal stability and the power handing capability of power device. Experimental results verify our conclusious.
Heber, Ulrich; Bilger, Wolfgang; Türk, Roman; Lange, Otto L
2010-01-01
*The photobionts of lichens have previously been shown to reversibly inactivate their photosystem II (PSII) upon desiccation, presumably as a photoprotective mechanism. The mechanism and the consequences of this process have been investigated in the green algal lichen Lobaria pulmonaria. *Lichen thalli were collected from a shaded and a sun-exposed site. The activation of PSII was followed by chlorophyll fluorescence measurements. *Inactivation of PSII, as indicated by the total loss of variable fluorescence, was accompanied by a strong decrease of basal fluorescence (F(0)). Sun-grown thalli, as well as thalli exposed to low irradiance during drying, showed a larger reduction of F(0) than shade-grown thalli or thalli desiccated in the dark. Desiccation increased phototolerance, which was positively correlated to enhanced quenching of F(0). Quenching of F(0) could be reversed by heating, and could be inhibited by glutaraldehyde but not by the uncoupler nigericin. *Activation of energy dissipation, apparent as F(0) quenching, is proposed to be based on an alteration in the conformation of a pigment protein complex. This permits thermal energy dissipation and gives considerable flexibility to photoprotection. Zeaxanthin formation apparently did not contribute to the enhancement of photoprotection by desiccation in the light. Light-induced absorbance changes indicated the involvement of chlorophyll and carotenoid cation radicals. PMID:19863730
Statistical investigation and thermal properties for a 1-D impact system with dissipation
Díaz I., Gabriel; Livorati, André L. P.; Leonel, Edson D.
2016-05-01
The behavior of the average velocity, its deviation and average squared velocity are characterized using three techniques for a 1-D dissipative impact system. The system - a particle, or an ensemble of non-interacting particles, moving in a constant gravitation field and colliding with a varying platform - is described by a nonlinear mapping. The average squared velocity allows to describe the temperature for an ensemble of particles as a function of the parameters using: (i) straightforward numerical simulations; (ii) analytically from the dynamical equations; (iii) using the probability distribution function. Comparing analytical and numerical results for the three techniques, one can check the robustness of the developed formalism, where we are able to estimate numerical values for the statistical variables, without doing extensive numerical simulations. Also, extension to other dynamical systems is immediate, including time dependent billiards.
Measurements of mechanical thermal noise and energy dissipation in optical dielectric coatings
Li, Tianjun; Geitner, Mickael; Cagnoli, Gianpietro; Dolique, Vincent; Degallaix, Jérôme; Flaminio, Raffaele; Forest, Danièle; Granata, Massimo; Michel, Christophe; Morgado, Nazario; Pinard, Laurent; Bellon, Ludovic
2014-01-01
In recent years an increasing number of devices and experiments are shown to be limited by mechanical thermal noise. In particular sub-Hertz laser frequency stabilization and gravitational wave detectors, that are able to measure fluctuations of 1E-18 m/rtHz or less, are being limited by thermal noise in the dielectric coatings deposited on mirrors. In this paper we present a new measurement of thermal noise in low absorption dielectric coatings deposited on micro-cantilevers and we compare it with the results obtained from the mechanical loss measurements. For the first time the coating thermal noise is measured on a wide range of frequencies with high signal to noise ratio. In addition we present a novel technique to deduce the coating mechanical losses from the measurement of the mechanical quality factor which does not rely on the knowledge of the coating and substrate Young moduli. The dielectric coatings are deposited by ion beam sputtering. The results presented here give a frequency independent loss a...
Xia, X.; Zhang, H. Y.; Deng, Y. C.
2016-08-01
Solid-fluid phase change materials have been of increasing interest in various applications due to their high latent heat with minimum volume change. In this work, numerical analysis of phase change materials is carried out for the purpose of thermal control of the cylindrical power battery cells for applications in electric vehicles. Uniform heat density is applied at the battery cell, which is surrounded by phase change material (PCM) of paraffin wax type and contained in a metal housing. A two-dimensional geometry model is considered due to the model symmetry. The effects of power densities, heat transfer coefficients and onset melting temperatures are examined for the battery temperature evolution. Temperature plateaus can be observed from the present numerical analysis for the pure PCM cases, with the temperature level depending on the power densities, heat transfer coefficients, and melting temperatures. In addition, the copper foam of high thermal conductivity is inserted into the copper foam to enhance the heat transfer. In the modeling, the local thermal non-equilibrium between the metal foam and the PCM is taken into account and the temperatures for the metal foam and PCM are obtained respectively.
DEFF Research Database (Denmark)
Antonov, A. A.; Pankratov, A. L.; Yulin, A. V.;
2000-01-01
The nonlinear dynamics of fluxons in Josephson systems with dispersion and thermal fluctuations is analyzed using the "quasiparticle" approach to investigate the influence of noise on the Cherenkov radiation effect. Analytical expressions for the stationary amplitude of the emitted radiation...... and its spectral distribution have been obtained in an annular geometry. It is demonstrated that noise reduces the amplitude of the radiated wave and broadens its spectrum. The effect of the radiated wave on the fluxon dynamics leads to a considerably smaller linewidth than observed in the usual flux flow...... oscillator. A resonant behavior of both the mean amplitude and the linewidth as functions of bias current is found. The obtained results enable an optimization of the main parameters (power, tunability, and linewidth) of practical mm- and sub-mm wave Cherenkov flux flow oscillators....
Legal and regulatory issues affecting aquifer thermal energy storage
Energy Technology Data Exchange (ETDEWEB)
Hendrickson, P.L.
1981-10-01
This document updates and expands the report with a similar title issued in October 1980. This document examines a number of legal and regulatory issues that potentially can affect implementation of the aquifer thermal energy storage (ATES) concept. This concept involves the storage of thermal energy in an underground aquifer until a later date when it can be effectively utilized. Either heat energy or chill can be stored. Potential end uses of the energy include district space heating and cooling, industrial process applications, and use in agriculture or aquaculture. Issues are examined in four categories: regulatory requirements, property rights, potential liability, and issues related to heat or chill delivery.
Surface modification of layered silicates. II. Factors affecting thermal stability
Mittal, Vikas
2012-12-01
Different aluminosilicates, such as montmorillonite, vermiculite and mica, were surface-treated with a variety of organic modifiers to quantify factors affecting the thermal stability of the modified fillers. Montmorillonites with different cation exchange capacities were also used. Thermal characterisation was carried out via high resolution thermogravimetric analysis and the results were correlated with X-ray diffraction measurements. Modified substrates, such as montmorillonite, vermiculite and mica, differed in their thermal behaviour even when modified with the same surface modifiers. Phosphonium-based modifiers were the most thermally stable, compared to pyridinium and ammonium ions. Mixed brushes from the modifiers also influenced the thermal behaviour of the modified substrates. When further modified using physical adsorption or chemical reactions on the surface, the modified minerals also displayed alterations in the thermal behaviour of the fillers. The results can be used as a guide for the selection of surface modifiers in the nanocomposite synthesis process where compounding of the filler with the polymer at high temperature and shear is required.
Physical factors affecting the electrically assisted thermal bitumen recovery
Energy Technology Data Exchange (ETDEWEB)
Bogdanov, I.I.; Torres, J.-A.; Kamp, A.M. [CHLOE, University of Pau (France); Corre, B. [CSTJF, Total (France)
2011-07-01
In the heavy oil industry, thermal processes are used to enhance oil recovery by increasing the reservoir temperature which results in better oil mobility. Low frequency heating (LFH) is a technology using electrical conductivity of connate water to propagate current between electrodes, thus generating heat in the reservoir through the Joule effect. During the preheating and production periods, many physical factors may affect the LFH process and the aim of this study was to determine which factors affect the process and how, using a particular pattern of electrodes. Simulations were conducted using the CMG Stars reservoir simulator under different configurations, conditions and parameters. Important physical properties and operational conditions affecting the LFH process were determined and results showed that convection heat, bulk electrical conductivity and power distribution can be improved by salt water circulation. This paper highlighted the physical factors affecting LFH efficiency and these findings will be useful for future process design.
Surface modification of layered silicates. I. Factors affecting thermal stability
Mittal, Vikas
2012-12-01
The resistance of modification molecules bound to montmorillonite platelet surfaces towards structural damage at high temperature is a major parameter guiding the formation of optimal interface between the filler and polymer phases in a nanocomposite material. As nanocomposites are generated by melt-blending of modified mineral and polymer, it is necessary to quantify the thermal resistance of the filler surface modification at the compounding conditions because different modifications differ in chain length, chemical structure, chain density, and thermal performance. A number of different alkyl ammonium modifications were exchanged on the montmorillonites with cation exchange capacities in the range 680-900 µequiv. g-1 and their thermal behaviour was characterised using high resolution thermogravimetric analysis. Quantitative comparisons between different modified minerals were achieved by comparing temperature at 10% weight loss as well peak degradation temperature. Various factors affecting thermal stability, such as length and density (or number) of alkyl chains in the modification, presence of excess modification molecules on the filler surface, the chemical structure of the surface modifications, etc. were studied. The TGA findings were also correlated with X-ray diffraction of the modified platelets.
Institute of Scientific and Technical Information of China (English)
Feng Lin; Jiu Li Luo; Nan Rong Zhao
2011-01-01
By means of a stochastic model suggested in this paper for the systems with local non-equilibrium excited thermal fluctuations, the famous Shannon entropy is extended to include the heat conduction processes controlled externally by boundary constraints of constant temperature gradients at two sides. Meanwhile, using the description of master equation for the continuous Markov processes a balance equation of stochastic entropy production valid for one dimension gaseous heat conduction systems with high values of Prandtl number has been also established. Based on it, a general expression for both the stochastic entropy production and the entropy production of fluctuations have been further deduced by the O-expansions. In this formalism, all kinds of stochastic contributions to the dissipation from the non-equilibrium thermal fluctuation and internal noise turn explicit.
Factors affecting thermal infrared images at selected field sites
Energy Technology Data Exchange (ETDEWEB)
Sisson, J.B.; Ferguson, J.S.
1993-07-01
A thermal infrared (TIR) survey was conducted to locate surface ordnance in and around the Naval Ordnance Disposal Area, and a thermal anomaly was found. This report documents studies conducted to identify the position of cause of the thermal anomaly. Also included are results of a long path Fourier transform infrared survey, soil sampling activities, soil gas surveys, and buried heater studies. The results of these studies indicated that the thermal anomaly was caused by a gravel pad, which had thermal properties different than those of the surrounding soil. Results from this investigation suggest that TIR is useful for locating surface objects having a high thermal inertia compared to the surrounding terrain, but TIR is of very limited use for characterizing buried waste or other similar buried objects at the INEL.
Factors affecting thermal infrared images at selected field sites
International Nuclear Information System (INIS)
A thermal infrared (TIR) survey was conducted to locate surface ordnance in and around the Naval Ordnance Disposal Area, and a thermal anomaly was found. This report documents studies conducted to identify the position of cause of the thermal anomaly. Also included are results of a long path Fourier transform infrared survey, soil sampling activities, soil gas surveys, and buried heater studies. The results of these studies indicated that the thermal anomaly was caused by a gravel pad, which had thermal properties different than those of the surrounding soil. Results from this investigation suggest that TIR is useful for locating surface objects having a high thermal inertia compared to the surrounding terrain, but TIR is of very limited use for characterizing buried waste or other similar buried objects at the INEL
Akbar, Noreen Sher; Tripathi, D.; Bég, O. Anwar; Khan, Z. H.
2016-11-01
A theoretical investigation of magnetohydrodynamic (MHD) flow and heat transfer of electrically-conducting viscoplastic fluids through a channel is conducted. The robust Casson model is implemented to simulate viscoplastic behavior of fluids. The external magnetic field is oblique to the fluid flow direction. Viscous dissipation effects are included. The flow is controlled by the metachronal wave propagation generated by cilia beating on the inner walls of the channel. The mathematical formulation is based on deformation in longitudinal and transverse velocity components induced by the ciliary beating phenomenon with cilia assumed to follow elliptic trajectories. The model also features velocity and thermal slip boundary conditions. Closed-form solutions to the non-dimensional boundary value problem are obtained under physiological limitations of low Reynolds number and large wavelength. The influence of key hydrodynamic and thermo-physical parameters i.e. Hartmann (magnetic) number, Casson (viscoplastic) fluid parameter, thermal slip parameter and velocity slip parameter on flow characteristics are investigated. A comparative study is also made with Newtonian fluids (corresponding to massive values of plastic viscosity). Stream lines are plotted to visualize trapping phenomenon. The computations reveal that velocity increases with increasing the magnitude of Hartmann number near the channel walls whereas in the core flow region (center of the channel) significant deceleration is observed. Temperature is elevated with greater Casson parameter, Hartmann number, velocity slip, eccentricity parameter, thermal slip and also Brinkmann (dissipation) number. Furthermore greater Casson parameter is found to elevate the quantity and size of the trapped bolus. In the pumping region, the pressure rise is reduced with greater Hartmann number, velocity slip, and wave number whereas it is enhanced with greater cilia length.
Campos, Huitziméngari; Trejo, Carlos; Peña-Valdivia, Cecilia B; García-Nava, Rodolfo; Conde-Martínez, F Víctor; Cruz-Ortega, Ma Del Rocío
2014-10-01
Agave salmiana Otto ex Salm-Dyck, a crassulacean acid metabolism plant that is adapted to water-limited environments, has great potential for bioenergy production. However, drought stress decreases the requirement for light energy, and if the amount of incident light exceeds energy consumption, the photosynthetic apparatus can be injured, thereby limiting plant growth. The objective of this study was to evaluate the effects of drought and re-watering on the photosynthetic efficiency of A. salmiana seedlings. The leaf relative water content and leaf water potential decreased to 39.6 % and -1.1 MPa, respectively, over 115 days of water withholding and recovered after re-watering. Drought caused a direct effect on photosystem II (PSII) photochemistry in light-acclimated leaves, as indicated by a decrease in the photosynthetic electron transport rate. Additionally, down-regulation of photochemical activity occurred mainly through the inactivation of PSII reaction centres and an increased thermal dissipation capacity of the leaves. Prompt fluorescence kinetics also showed a larger pool of terminal electron acceptors in photosystem I (PSI) as well as an increase in some JIP-test parameters compared to controls, reflecting an enhanced efficiency and specific fluxes for electron transport from the plastoquinone pool to the PSI terminal acceptors. All the above parameters showed similar levels after re-watering. These results suggest that the thermal dissipation of excess energy and the increased energy conservation from photons absorbed by PSII to the reduction of PSI end acceptors may be an important acclimation mechanism to protect the photosynthetic apparatus from over-excitation in Agave plants. PMID:24798124
Waves in vertically inhomogeneous dissipative atmosphere
Dmitrienko, I S
2015-01-01
A method of construction of solution for acoustic-gravity waves (AGW) above a wave source, taking dissipation throughout the atmosphere into account (Dissipative Solution above Source, DSAS), is proposed. The method is to combine three solutions for three parts of the atmosphere: an analytical solution for the upper isothermal part and numerical solutions for the real non-isothermal dissipative atmosphere in the middle part and for the real non-isothermal small dissipation atmosphere in the lower one. In this paper the method has been carried out for the atmosphere with thermal conductivity but without viscosity. The heights of strong dissipation and the total absorption index in the regions of weak and average dissipation are found. For internal gravity waves the results of test calculations for an isothermal atmosphere and calculations for a real non-isothermal atmosphere are shown in graphical form. An algorithm and appropriate code to calculate DSAS, taking dissipation due to finite thermal conductivity i...
Pahlavani, M. R.; Mirfathi, S. M.
2016-04-01
The incorporation of the four-dimensional Langevin equations led to an integrative description of fission cross-section, fragment mass distribution and the multiplicity and energy distribution of prompt neutrons and γ-rays in the thermal neutron-induced fission of 239Pu. The dynamical approach presented in this paper thoroughly reproduces several experimental observables of the fission process at low excitation energy.
Energy Technology Data Exchange (ETDEWEB)
Pahlavani, M.R.; Mirfathi, S.M. [University of Mazandaran, Department of Nuclear Physics, Faculty of Basic Science, Babolsar (Iran, Islamic Republic of)
2016-04-15
The incorporation of the four-dimensional Langevin equations led to an integrative description of fission cross-section, fragment mass distribution and the multiplicity and energy distribution of prompt neutrons and γ-rays in the thermal neutron-induced fission of {sup 239}Pu. The dynamical approach presented in this paper thoroughly reproduces several experimental observables of the fission process at low excitation energy. (orig.)
Directory of Open Access Journals (Sweden)
Mehmet Camurdan
1998-01-01
are coupled by appropriate trace operators. This overall model differs from those previously studied in the literature in that the elastic chamber floor is here more realistically modeled by a hyperbolic Kirchoff equation, rather than by a parabolic Euler-Bernoulli equation with Kelvin-Voight structural damping, as in past literature. Thus, the hyperbolic/parabolic coupled system of past literature is replaced here by a hyperbolic/hyperbolic coupled model. The main result of this paper is a uniform stabilization of the coupled PDE system by a (physically appealing boundary dissipation.
Hydraulic modeling of thermal discharges into shallow, tidal affected streams
International Nuclear Information System (INIS)
A two-unit nuclear fired power plant is being constructed in western Washington state. Blowdown water from cooling towers will be discharged into the Chehalis River nearby. The location of a diffuser is some 21 miles upriver from Grays Harbor on the Pacific Ocean. Because the Chehalis River is classified as an excellent stream from the standpoint of water quality, State regulatory agencies required demonstration that thermal discharges would maintain water quality standards within fairly strict limits. A hydraulic model investigation used a 1:12 scale, undistorted model of a 1300-foot river reach in the vicinity of the diffuser. The model scale was selected to insure fully turbulent flows both in the stream and from the diffuser (Reynolds similitude). Model operation followed the densimetric Froude similitude. Thermistors were employed to measure temperatures in the model; measurements were taken by computer command and such measurements at some 250 positions were effected in about 2.5 seconds
Study of thermal stress in heat affected zones during welding
International Nuclear Information System (INIS)
The importance of applications of welding in the nuclear industry leads to the study of the main problem concerning metal welding: sensibility to cracking. The development of computation methods allows the numerical simulation of welding effects. Due to the complexity of this problem, it is divided in three steps: thermal, metallurgical and mechanical calculus. Interactions between the 3 steps are examined. Mathematical models necessary to get residual stress (i.e. stress remaining when welding is completed and structure at ambient temperature) are described. Then parameters for metallurgical structure determination are given and compared to experiments. A508 and A533 type steels of primary coolant circuit of PWR reactors are taken as examples and the numerical simulation of a test is presented
Institute of Scientific and Technical Information of China (English)
Joaquín Zueco; O. Anwar Bég; L.M. López-Ochoa
2011-01-01
Network simulation method (NSM) is used to solve the laminar heat and mass transfer of an electricallyconducting, heat generating/absorbing fluid past a perforated horizontal surface in the presence of viscous and Joule heating problem. The governing partial differential equations are non-dimensionalized and transformed into a system of nonlinear ordinary differential similarity equations, in a single independent variable, η. The resulting coupled, nonlinear equations are solved under appropriate transformed boundary conditions. Computations are performed for a wide range of the governing flow parameters, viz Prandtl number, thermophoretic coefficient (a function of Knudsen number), thermal conductivity parameter, wall transpiration parameter and Schmidt number. The numerical details are discussed with relevant applications. The present problem finds applications in optical fiber fabrication, aerosol filter precipitators, particle deposition on hydronautical blades, semiconductor wafer design, thermo-electronics and problems including nuclear reactor safety.
Directory of Open Access Journals (Sweden)
Kishore P.M.
2012-01-01
Full Text Available This investigation is undertaken to study the hydromagnetic flow of a viscous incompressible fluid past an oscillating vertical plate embedded in a porous medium with radiation, viscous dissipation and variable heat and mass diffusion. Governing equations are solved by unconditionally stable explicit finite difference method of DuFort - Frankel’s type for concentration, temperature, vertical velocity field and skin - friction and they are presented graphically for different values of physical parameters involved. It is observed that plate oscillation, variable mass diffusion, radiation, viscous dissipation and porous medium affect the flow pattern significantly.
Thermal fluctuations affect the transcriptome through mechanisms independent of average temperature.
Sørensen, Jesper Givskov; Schou, Mads Fristrup; Kristensen, Torsten Nygaard; Loeschcke, Volker
2016-01-01
Terrestrial ectotherms are challenged by variation in both mean and variance of temperature. Phenotypic plasticity (thermal acclimation) might mitigate adverse effects, however, we lack a fundamental understanding of the molecular mechanisms of thermal acclimation and how they are affected by fluctuating temperature. Here we investigated the effect of thermal acclimation in Drosophila melanogaster on critical thermal maxima (CTmax) and associated global gene expression profiles as induced by two constant and two ecologically relevant (non-stressful) diurnally fluctuating temperature regimes. Both mean and fluctuation of temperature contributed to thermal acclimation and affected the transcriptome. The transcriptomic response to mean temperatures comprised modification of a major part of the transcriptome, while the response to fluctuations affected a much smaller set of genes, which was highly independent of both the response to a change in mean temperature and to the classic heat shock response. Although the independent transcriptional effects caused by fluctuations were relatively small, they are likely to contribute to our understanding of thermal adaptation. We provide evidence that environmental sensing, particularly phototransduction, is a central mechanism underlying the regulation of thermal acclimation to fluctuating temperatures. Thus, genes and pathways involved in phototransduction are likely of importance in fluctuating climates. PMID:27487917
Renninger, Heidi J; Schäfer, Karina V R
2012-01-01
Sap flow measurements have become integral in many physiological and ecological investigations. A number of methods are used to estimate sap flow rates in trees, but probably the most popular is the thermal dissipation (TD) method because of its affordability, relatively low power consumption, and ease of use. However, there have been questions about the use of this method in ring-porous species and whether individual species and site calibrations are needed. We made concurrent measurements of sap flow rates using TD sensors and the tissue heat balance (THB) method in two oak species (Quercus prinus Willd. and Quercus velutina Lam.) and one pine (Pinus echinata Mill.). We also made concurrent measurements of sap flow rates using both 1 and 2-cm long TD sensors in both oak species. We found that both the TD and THB systems tended to match well in the pine individual, but sap flow rates were underestimated by 2-cm long TD sensors in five individuals of the two ring-porous oak species. Underestimations of 20-35% occurred in Q. prinus even when a "Clearwater" correction was applied to account for the shallowness of the sapwood depth relative to the sensor length and flow rates were underestimated by up to 50% in Q. velutina. Two centimeter long TD sensors also underestimated flow rates compared with 1-cm long sensors in Q. prinus, but only at large flow rates. When 2-cm long sensor data in Q. prinus were scaled using the regression with 1-cm long data, daily flow rates matched well with the rates measured by the THB system. Daily plot level transpiration estimated using TD sap flow rates and scaled 1 cm sensor data averaged about 15% lower than those estimated by the THB method. Therefore, these results suggest that 1-cm long sensors are appropriate in species with shallow sapwood, however more corrections may be necessary in ring-porous species.
Hamada, Joël; Pétrissans, Anélie; Mothe, Frédéric; Ruelle, Julien; Pétrissans, Mathieu; Gérardin, Philippe
2016-01-01
International audience AbstractKey messageThermogravimetric analysis, performed on small samples of earlywood (EW) or latewood (LW), indicated that earlywood is more susceptible to thermal degradation than latewood. These results suggest a direct relationship between wood density (which depends on the EW/LW ratio and indirectly on silviculture) and the response of wood during thermo-modification processes.ContextOne of the main difficulties in developing thermo-modified wood products at an...
Directory of Open Access Journals (Sweden)
Tamaraukuro Tammy Amasuomo
2016-04-01
Full Text Available The study investigated the relationship between students’ perceived thermal discomfort and stress behaviours affecting their learning in lecture theatres in the humid tropics. Two lecture theatres, LTH-2 and 3, at the Niger Delta University, Nigeria, were used for the study. Two groups of students from the Faculties of Agriculture and Engineering and the Department of Technology Education constituted the population. The sample size selected through random sampling for Groups A and B was 210 and 370 students, respectively. Objective and self-report instruments were used for data collection. The objective instrument involved physical measurement of the two lecture theatres and of the indoor temperature, relative humidity and air movement. The self-report instrument was a questionnaire that asked for the students perceived indoor thermal discomfort levels and the effect of indoor thermal comfort level on perceived stress behaviours affecting their learning. The objective indoor environmental data indicated thermal discomfort with an average temperature of 29–32 °C and relative humidity of 78% exceeding the ASHARE [1] and Olgyay [2].The students’ experienced a considerable level of thermal discomfort and also perceived that stress behaviours due to thermal discomfort affected their learning. Further, there were no significant differences in the perceived thermal discomfort levels of the two groups of students in LTH-2 and 3. Furthermore, stress behaviours affecting learning as perceived by the two groups of students did not differ significantly. In addition, no correlation existed between the perceived indoor thermal discomfort levels and stress behaviour levels affecting learning for students in LTH-2, because the arousal level of the students in the thermal environment was likely higher than the arousal level for optimal performance [3,4]. However, a correlation existed in the case of students in LTH-3, which was expected because it only
Fejer, M M; Cagnoli, G; Crooks, D R M; Gretarsson, A M; Harry, G M; Hough, J; Penn, S D; Sneddon, P H; Vyatchanin, S P
2004-01-01
The displacement noise in the test mass mirrors of interferometric gravitational wave detectors is proportional to their elastic dissipation at the observation frequencies. In this paper, we analyze one fundamental source of dissipation in thin coatings, thermoelastic damping associated with the dissimilar thermal and elastic properties of the film and the substrate. We obtain expressions for the thermoelastic dissipation factor necessary to interpret resonant loss measurements, and for the spectral density of displacement noise imposed on a Gaussian beam reflected from the face of a coated mass. The predicted size of these effects is large enough to affect the interpretation of loss measurements, and to influence design choices in advanced gravitational wave detectors.
Richter-Boix, Alex; Katzenberger, Marco; Duarte, Helder; Quintela, María; Tejedo, Miguel; Laurila, Anssi
2015-08-01
Although temperature variation is known to cause large-scale adaptive divergence, its potential role as a selective factor over microgeographic scales is less well-understood. Here, we investigated how variation in breeding pond temperature affects divergence in multiple physiological (thermal performance curve and critical thermal maximum [CTmax]) and life-history (thermal developmental reaction norms) traits in a network of Rana arvalis populations. The results supported adaptive responses to face two main constraints limiting the evolution of thermal adaptation. First, we found support for the faster-slower model, indicating an adaptive response to compensate for the thermodynamic constraint of low temperatures in colder environments. Second, we found evidence for the generalist-specialist trade-off with populations from colder and less thermally variable environments exhibiting a specialist phenotype performing at higher rates but over a narrower range of temperatures. By contrast, the local optimal temperature for locomotor performance and CTmax did not match either mean or maximum pond temperatures. These results highlight the complexity of the adaptive multiple-trait thermal responses in natural populations, and the role of local thermal variation as a selective force driving diversity in life-history and physiological traits in the presence of gene flow. PMID:26118477
Legal and regulatory issues affecting the aquifer thermal energy storage concept
Energy Technology Data Exchange (ETDEWEB)
Hendrickson, P.L.
1980-10-01
A number of legal and regulatory issus that potentially can affect implementation of the Aquifer Thermal Energy Storage (ATES) concept are examined. This concept involves the storage of thermal energy in an underground aquifer until a later date when it can be effectively utilized. Either heat energy or chill can be stored. Potential end uses of the energy include district space heating and cooling, industrial process applications, and use in agriculture or aquaculture. Issues are examined in four categories: regulatory requirements, property rights, potential liability, and issues related to heat or chill delivery.
Enceladus' tidal dissipation revisited
Tobie, Gabriel; Behounkova, Marie; Choblet, Gael; Cadek, Ondrej; Soucek, Ondrej
2016-10-01
A series of chemical and physical evidence indicates that the intense activity at Enceladus' South Pole is related to a subsurface salty water reservoir underneath the tectonically active ice shell. The detection of a significant libration implies that this water reservoir is global and that the average ice shell thickness is about 20-25km (Thomas et al. 2016). The interpretation of gravity and topography data further predicts large variations in ice shell thickness, resulting in a shell potentially thinner than 5 km in the South Polar Terrain (SPT) (Cadek et al. 2016). Such an ice shell structure requires a very strong heat source in the interior, with a focusing mechanism at the SPT. Thermal diffusion through the ice shell implies that at least 25-30 GW is lost into space by passive diffusion, implying a very efficient dissipation mechanism in Enceladus' interior to maintain such an ocean/ice configuration thermally stable.In order to determine in which conditions such a large dissipation power may be generated, we model the tidal response of Enceladus including variable ice shell thickness. For the rock core, we consider a wide range of rheological parameters representative of water-saturated porous rock materials. We demonstrate that the thinning toward the South Pole leads to a strong increase in heat production in the ice shell, with a optimal thickness obtained between 1.5 and 3 km, depending on the assumed ice viscosity. Our results imply that the heat production in the ice shell within the SPT may be sufficient to counterbalance the heat loss by diffusion and to power eruption activity. However, outside the SPT, a strong dissipation in the porous core is required to counterbalance the diffusive heat loss. We show that about 20 GW can be generated in the core, for an effective viscosity of 1012 Pa.s, which is comparable to the effective viscosity estimated in water-saturated glacial tills on Earth. We will discuss the implications of this revisited tidal
Stabilizing entanglement against local dissipation
Energy Technology Data Exchange (ETDEWEB)
Sauer, Simeon; Gneiting, Clemens; Buchleitner, Andreas [Albert-Ludwigs-Universitaet, Freiburg (Germany)
2013-07-01
Natural dissipative processes in multipartite quantum systems are mostly of local nature and therefore affect entanglement adversely. In their presence, initially highly entangled states generically evolve into at most weakly entangled states. We investigate by what means this detrimental process can be counteracted. It is shown that a suitable, dissipator-adapted static system Hamiltonian can preserve entanglement in the stationary state to a significant but limited extend. We then extend our analysis to the general class of periodically driven Hamiltonians and show that they are subject to similar limitations. Finally, we develop incoherent but local control strategies which overcome these limits.
Quantum bouncer with dissipation
Energy Technology Data Exchange (ETDEWEB)
Lopez, G.; Gonzalez, G. [Departamento de Fisica de la Universidad de Guadalajara, AP 4-137, 44410 Guadalajara, Jalisco (Mexico)
2006-07-01
Effects on the spectra of the quantum bouncer due to dissipation are given when a linear o quadratic dissipation in the velocity of the particle is taken into account. Classical constants of motion and Hamiltonians are deduced for these systems and their quantized eigenvalues are estimated through perturbation theory. Differences were found comparing the eigenvalues of the constants of motion and the eigenvalues of the Hamiltonians. The cases when the dissipation parameters go to zero are compared with the non dissipative cases. (Author)
Experimental Study Abour How the Thermal Plume Affects the Air Quality a Person Breathes
DEFF Research Database (Denmark)
Olmedo, Inés; Nielsen, Peter V.; Ruiz de Adana, Manuel;
2011-01-01
The Personal Micro Environment (PME) depends directly on the heat transfer in the surrounding environment. For the displacement ventilation systems the convective transport mechanism, which is found in the thermal plume around a person, influences the human exposure to pollutants. The aim...... of this research is to increase the knowledge of how the thermal plume generated by a person affects the PME and therefore the concentration of contaminants in the inhalation area. An experimental study in a displacement ventilation room was carried out. Experiments were developed in a full scale test chamber 4.......10 m (length), 3.2 m (width), 2.7 m (height). The incoming air is distributed through a wall-mounted displacement diffuser. A breathing thermal manikin exhaling through the mouth and inhaling through the nose was used. A tracer gas, N2O, was used to simulate the gaseous substances, which might...
Bird population trends are linearly affected by climate change along species thermal ranges
Jiguet, Frédéric; Devictor, Vincent; Ottvall, Richard; Van Turnhout, Chris; van der Jeugd, Henk; Lindström, Åke
2010-01-01
Beyond the effects of temperature increase on local population trends and on species distribution shifts, how populations of a given species are affected by climate change along a species range is still unclear. We tested whether and how species responses to climate change are related to the populations locations within the species thermal range. We compared the average 20 year growth rates of 62 terrestrial breeding birds in three European countries along the latitudinal gradient of the spec...
Aubret, F; Shine, R
2010-01-15
Climate change will result in some areas becoming warmer and others cooler, and will amplify the magnitude of year-to-year thermal variation in many areas. How will such changes affect animals that rely on ambient thermal heterogeneity to behaviourally regulate their body temperatures? To explore this question, we raised 43 captive-born tiger snakes Notechis scutatus in enclosures that provided cold (19-22 degrees C), intermediate (19-26 degrees C) or hot (19-37 degrees C) thermal gradients. The snakes adjusted their diel timing of thermoregulatory behaviour so effectively that when tested 14 months later, body temperatures (mean and maximum), locomotor speeds and anti-predator behaviours did not differ among treatment groups. Thus, the young snakes modified their behaviour to compensate for restricted thermal opportunities. Then, we suddenly shifted ambient conditions to mimic year-to-year variation. In contrast to the earlier plasticity, snakes failed to adjust to this change, e.g. snakes raised at cooler treatments but then shifted to hot conditions showed a higher mean body temperature for at least two months after the onset of the new thermal regime. Hence, thermal conditions experienced early in life influenced subsequent thermoregulatory tactics; the mean selected temperature of a snake depended more upon its prior raising conditions than upon its current thermoregulatory opportunities. Behavioural plasticity thus allows snakes to adjust to suboptimal thermal conditions but this plasticity is limited. The major thermoregulatory challenge from global climate change may not be the shift in mean values (to which our young snakes adjusted) but the increased year-to-year variation (with which our snakes proved less able to deal).
Directory of Open Access Journals (Sweden)
Juan S. Delgado-Rojas
2006-12-01
. However, the effect of the natural radiation, that generates a natural thermal gradient in stem, may lead to precision loss. Moreover, the performance of the method needs to be evaluated if the conditions are different from those for which it was developed. Thus, the present work aimed to analyze the performance of the HDM in rubber trees, considering that this specie produces latex that could affect the performance of the sensor, as well as to evaluate the effect of the natural thermal gradient of the stem on the estimated transpiration. The results had showed that HDM can be used with rubber trees and, in the conditions that tests were conducted, the natural thermal gradient does not effect the estimations. To improve the precision of the method, further studies, characterizing the tissue sap conductive area and the stem diameter should be made.
Dissipation of acoustic-gravity waves: an asymptotic approach.
Godin, Oleg A
2014-12-01
Acoustic-gravity waves in the middle and upper atmosphere and long-range propagation of infrasound are strongly affected by air viscosity and thermal conductivity. To characterize the wave dissipation, it is typical to consider idealized environments, which admit plane-wave solutions. Here, an asymptotic approach is developed that relies instead on the assumption that spatial variations of environmental parameters are gradual. It is found that realistic assumptions about the atmosphere lead to rather different predictions for wave damping than do the plane-wave solutions. A modification to the Sutherland-Bass model of infrasound absorption is proposed. PMID:25480091
Circulation and Dissipation on Hot Jupiters
Li, Jason
2010-01-01
Many global circulation models predict supersonic zonal winds and large vertical shears in the atmospheres of short-period jovian exoplanets. Using linear analysis and nonlinear local simulations, we investigate hydrodynamic dissipation mechanisms to balance the thermal acceleration of these winds. The adiabatic Richardson criterion remains a good guide to linear stability, although thermal diffusion allows some modes to violate it at very long wavelengths and very low growth rates. Nonlinearly, wind speeds saturate at Mach numbers $\\approx 2$ and Richardson numbers $\\lesssim 1/4$ for a broad range of plausible diffusivities and forcing strengths. Turbulence and vertical mixing, though accompanied by weak shocks, dominate the dissipation, which appears to be the outcome of a recurrent Kelvin-Helmholtz instability. An explicit shear viscosity, as well as thermal diffusivity, is added to ZEUS to capture dissipation outside of shocks. The wind speed is not monotonic nor single valued for shear viscosities larger...
Lineback, L. D.
1974-01-01
The thermal shock resistance of hafnia based composites containing graphite powder or tungsten fibers was investigated in terms of material properties which include thermal expansion, thermal conductivity, compressive fracture stress, modulus of elasticity, and phase stability in terms of the processing parameters of hot pressing pressure and/or density, degree of stabilization of the hafnia, and composition. All other parameters were held constant or assumed constant. The thermal shock resistance was directly proportional to the compressive fracture stress to modulus of elasticity ratio and was not affected appreciably by the small thermal expansion or thermal conductivity changes. This ratio was found to vary strongly with the composition and density such that the composites containing graphite had relatively poor thermal shock resistance, while the composites containing tungsten had superior thermal shock resistance.
Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load
Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan
2008-01-01
NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.
The fluctuation-dissipation dynamics of cosmological scalar fields
Bartrum, Sam; Rosa, Joao G
2014-01-01
We show that dissipative effects have a significant impact on the evolution of cosmological scalar fields, leading to friction, entropy production and field fluctuations. We explicitly compute the dissipation coefficient for different scalar fields within the Standard Model and some of its most widely considered extensions, in different parametric regimes. We describe the generic consequences of fluctuation-dissipation dynamics in the post-inflationary universe and analyze in detail two important effects. Firstly, we show that dissipative friction delays the process of spontaneous symmetry breaking and may even damp the the motion of a Higgs field sufficiently to induce a late period of warm inflation. Along with dissipative entropy production, this may parametrically dilute the abundance of dangerous thermal relics. Secondly, we show that dissipation can generate the observed baryon asymmetry without symmetry restoration, and we develop in detail a model of dissipative leptogenesis. We further show that this...
Thermal DissiPation AnalYsis of EleCtriC motorCYCle Controller%电动摩托车控制器的散热性能分析
Institute of Scientific and Technical Information of China (English)
凌智勇; 缪友谊; 邢雷杰
2015-01-01
分析了电动摩托车控制器的主要热源金属———氧化物半导体场效应晶体管（MOS-FET）的功率损耗并进行了理论计算，根据控制器总散热热阻对控制器的散热底板进行热设计，运用 CFD 软件 FloEFD 对控制器整体的热设计进行数值分析，得出控制器的温度分布。针对控制器最大功率损耗下的散热性能，分析了散热底板上的不同散热翅片参数对控制器整体温度分布的影响。实验结果表明：针对控制热散热性能的仿真误差小于10%，验证了仿真的合理性，优化后的散热底板可以满足控制器的散热需求。%AbstraCt:The power loss of the metal oxide semiconductor field effect transistor(MOSFET)in elec-tric motorcycle controller was calculated and analyzed. The controller thermal baseplate was designed according to the total thermal resistance,and the controller temperature distribution was simulated by the FloEFD. Based on the controller heat dissipation performance under maximum power loss,the in-fluence of the different thermal fin parameters on controller temperature distribution was analyzed. The experimental results verify the rationality of simulation,and the simulation deviation of controller ther-mal performance is less than 10% . The optimized baseplate can meet the thermal dissipation require-ments of controller.
Directory of Open Access Journals (Sweden)
Dessie Hunegnaw
2015-01-01
Full Text Available The effects of variable viscosity and thermal conductivity on MHD heat transfer flow of viscous incompressible electrically conducting fluid near stagnation point flow on non-conducting stretching sheet in presence of uniform transfer magnetic field with heat source/sink and viscous dissipation has been analyzed. The governing partial differential equations are transformed into ordinary differential equations using a special form of Lie group transformations and then solved using Fourth order Runge-Kutta Method. Effects of different physical parameters on the flow and heat transfer characteristics are analyzed. Variations of different parameters on skin fiction coefficient-f′′(0 and temperature gradient −θ′(0 are presented in tabular form.
Najafi, Amin
2014-05-01
Using the Monte Carlo simulations, we have calculated mean-square fluctuations in statistical mechanics, such as those for colloids energy configuration are set on square 2D periodic substrates interacting via a long range screened Coulomb potential on any specific and fixed substrate. Random fluctuations with small deviations from the state of thermodynamic equilibrium arise from the granular structure of them and appear as thermal diffusion with Gaussian distribution structure as well. The variations are showing linear form of the Fluctuation-Dissipation Theorem on the energy of particles constitutive a canonical ensemble with continuous diffusion process of colloidal particle systems. The noise-like variation of the energy per particle and the order parameter versus the Brownian displacement of sum of large number of random steps of particles at low temperatures phase are presenting a markovian process on colloidal particles configuration, too.
Energy Technology Data Exchange (ETDEWEB)
Pal, Dulal, E-mail: dulalp123@rediffmail.com [Department of Mathematics, Siksha-Bhavana, Visva-Bharati University, Santiniketan, West Bengal-731235 (India); Mondal, Hiranmoy, E-mail: hiranmoymondal@yahoo.co.in [Department of Mathematics, Bengal Institute of Technology and Management, Santiniketan, West Bengal-731236 (India)
2013-04-15
The present paper deals with the thermophoresis particle deposition and Soret–Dufour effects on the convective flow, heat and mass transfer characteristics of an incompressible Newtonian electrically conducting fluid having temperature-dependent viscosity over a non-isothermal wedge in the presence of thermal radiation. The governing boundary layer equations are written into a dimensionless form by similarity transformations. The transformed coupled non-linear ordinary differential equations are solved numerically. The effects of various important physical parameters are analyzed in detail. It is found that the skin friction coefficient and the local Sherwood number increase with increase in the values of thermal radiation parameter in the presence of heat generation/absorption whereas reverse effect is seen on the local Nusselt number. -- Highlights: ► The effect of thermophoresis of particle deposition is to increase the concentration. ► Temperature in the thermal boundary layer decreases with increasing Soret number. ► Skin friction increases with increase in the thermal radiation and heat generation/absorption. ► Local Sherwood number increases with increase in the thermal radiation and heat generation/absorption. ► Local Nusselt number decreases with increase in the thermal radiation.
Stenner, Paul; Greco, Monica
2013-01-01
The concept of affectivity has assumed central importance in much recent scholarship, and many in the social sciences and humanities now talk of an ‘affective turn’. The concept of affectivity at play in this ‘turn’ remains, however, somewhat vague and slippery. Starting with Silvan Tomkins’ influential theory of affect, this paper will explore the relevance of the general assumptions (or ‘utmost abstractions’) that inform thinking about affectivity. The technological and instrumentalist char...
International Nuclear Information System (INIS)
Highlights: • A practical thermal analysis of underground power cable system. • The geological measurements were performed for cable line placement location. • Dry zone formation effect included in soil and FTB thermal conductivity formula. • A simplified FEM model of underground power cable system. • The computational numerical code validation with ANSYS. - Abstract: This paper presents the thermal analysis of the underground transmission line, planned to be installed in one of the Polish power plants. The computations are performed by using the Finite Element Method (FEM) code, developed by the authors. The paper considers a system of three power cables arranged in flat (in-line) formation. The cable line is buried in the multilayered soil. The soil layers characteristic and thermal properties are determined from geological measurements. Different conditions of cable bedding are analyzed including power cables placement in the FTB or direct burial in a mother ground. The cable line burial depth, measured from the ground level, varies from 1 m to 2.5 m. Additionally, to include the effect of dry zones formation on the temperature distribution in cable line and surroundings, soil and FTB thermal conductivities are considered as a temperature-dependent. The proposed approach for determining the temperature-dependent thermal conductivity of soil layers is discussed in detail. The FEM simulation results are also compared with the results of the simulation that consider soil layers as homogeneous materials. Therefore, thermal conductivity is assumed to be constant for each layer. The results obtained by using the FEM code, developed by the authors, are compared with the results of ANSYS simulations, and a good agreement was found
Institute of Scientific and Technical Information of China (English)
张红平; 李牧; 阚明先; 王刚华; 种涛
2015-01-01
To study the pressure-specific volume (p-v )reference line and equation of state from the stress-strain curve of material at high pressure,the viscous dissipation due to loading strain rate and thermal dissipation due to irreversible heat conduction in quasi-isentropic compression experiment (ICE)were discussed and analyzed.A backward integration and forward integration method was used to analyze the data in laser driving and magnetic pressure driving ICE with different strain rates.For viscous dissipation,the sound speed,stress-strain curve,temperature and entropy production during loading were obtained,and the relations between high strain rate and these physical quantities were discussed.For thermal dissipation,through the calculation of the thermal conduction and SCG consti-tutive model,the variation of temperature and the corresponding yield strength,shear module and sound speed were presented.The results show that:in the laser driving ICE with a high strain rate of 10 8 s-1 ),the temperature variation caused by high strain rate is about 180 K,and the entropy produc-tion due to heat conduction is about 250 J/(kg·K);and in the magnetic pressure driving with a rela-tively low strain rate of 10 5 s-1 ,the entropy production is less than 8 J/(kg·K).%为获取高压下材料的纯热力学压力-比容参考线和完全物态方程,减去应力-应变曲线中的其它信息,对准等熵压缩实验中由加载应变率引起的黏性耗散和热传导引起的热耗散做了分析讨论。基于反积分计算和流体动力学积分计算相结合的方法,根据激光加载(约108 s-1)和磁驱动准等熵压缩(约105 s-1)的实验数据,对材料声速、应力-应变曲线、温度和熵增等物理量进行计算,分析了不同应变率与该物理量的关系；还对热传导和 SCG 本构模型进行了计算,分析了热传导引起的温度变化对材料屈服强度、剪切模量和拉格朗日声速的影响。结果表明：激光加载实验
Directory of Open Access Journals (Sweden)
Floris M van Beest
Full Text Available BACKGROUND: Empirical tests that link temperature-mediated changes in behaviour (activity and resource selection to individual fitness or condition are currently lacking for endotherms yet may be critical to understanding the effect of climate change on population dynamics. Moose (Alces alces are thought to suffer from heat stress in all seasons so provide a good biological model to test whether exposure to non-optimal ambient temperatures influence seasonal changes in body mass. Seasonal mass change is an important fitness correlate of large herbivores and affects reproductive success of female moose. METHODOLOGY/PRINCIPAL FINDINGS: Using GPS-collared adult female moose from two populations in southern Norway we quantified individual differences in seasonal activity budget and resource selection patterns as a function of seasonal temperatures thought to induce heat stress in moose. Individual body mass was recorded in early and late winter, and autumn to calculate seasonal mass changes (n = 52 over winter, n = 47 over summer. We found large individual differences in temperature-dependent resource selection patterns as well as within and between season variability in thermoregulatory strategies. As expected, individuals using an optimal strategy, selecting young successional forest (foraging habitat at low ambient temperatures and mature coniferous forest (thermal shelter during thermally stressful conditions, lost less mass in winter and gained more mass in summer. CONCLUSIONS/SIGNIFICANCE: This study provides evidence that behavioural responses to temperature have important consequences for seasonal mass change in moose living in the south of their distribution in Norway, and may be a contributing factor to recently observed declines in moose demographic performance. Although the mechanisms that underlie the observed temperature mediated habitat-fitness relationship remain to be tested, physiological state and individual variation in
Cooperstone, Jessica L; Francis, David M; Schwartz, Steven J
2016-11-01
Tangerine tomatoes, unlike red tomatoes, accumulate cis-lycopenes instead of the all-trans isomer. cis-Lycopene is the predominating isomeric form of lycopene found in blood and tissues. Our objective was to understand how thermal processing and lipid concentration affect carotenoid isomerisation and degradation in tangerine tomatoes. We conducted duplicated factorial designed experiments producing tangerine tomato juice and sauce, varying both processing time and lipid concentration. Carotenoids were extracted and analysed using high-performance liquid chromatography with photodiode array detection. Phytoene, phytofluene, ζ-carotene, neurosporene, tetra-cis-lycopene, all-trans-lycopene and other-cis-lycopenes were quantified. Tetra-cis-lycopene decreased with increasing heating time and reached 80% of the original level in sauce after processing times of 180min. All-trans-lycopene and other-cis-lycopenes increased with longer processing times. Total carotenoids and total lycopene decreased with increased heating times while phytoene and phytofluene were unchanged. These data suggest limiting thermal processing of tangerine tomato products if delivery of tetra-cis-lycopene is desirable. PMID:27211672
Spatial environmental heterogeneity affects plant growth and thermal performance on a green roof.
Buckland-Nicks, Michael; Heim, Amy; Lundholm, Jeremy
2016-05-15
Green roofs provide ecosystem services, including stormwater retention and reductions in heat transfer through the roof. Microclimates, as well as designed features of green roofs, such as substrate and vegetation, affect the magnitude of these services. Many green roofs are partially shaded by surrounding buildings, but the effects of this within-roof spatial environmental heterogeneity on thermal performance and other ecosystem services have not been examined. We quantified the effects of spatial heterogeneity in solar radiation, substrate depth and other variables affected by these drivers on vegetation and ecosystem services in an extensive green roof. Spatial heterogeneity in substrate depth and insolation were correlated with differential growth, survival and flowering in two focal plant species. These effects were likely driven by the resulting spatial heterogeneity in substrate temperature and moisture content. Thermal performance (indicated by heat flux and substrate temperature) was influenced by spatial heterogeneity in vegetation cover and substrate depth. Areas with less insolation were cooler in summer and had greater substrate moisture, leading to more favorable conditions for plant growth and survival. Spatial variation in substrate moisture (7%-26% volumetric moisture content) and temperature (21°C-36°C) during hot sunny conditions in summer could cause large differences in stormwater retention and heat flux within a single green roof. Shaded areas promote smaller heat fluxes through the roof, leading to energy savings, but lower evapotranspiration in these areas should reduce stormwater retention capacity. Spatial heterogeneity can thus result in trade-offs between different ecosystem services. The effects of these spatial heterogeneities are likely widespread in green roofs. Structures that provide shelter from sun and wind may be productively utilized to design higher functioning green roofs and increase biodiversity by providing habitat
Spatial environmental heterogeneity affects plant growth and thermal performance on a green roof.
Buckland-Nicks, Michael; Heim, Amy; Lundholm, Jeremy
2016-05-15
Green roofs provide ecosystem services, including stormwater retention and reductions in heat transfer through the roof. Microclimates, as well as designed features of green roofs, such as substrate and vegetation, affect the magnitude of these services. Many green roofs are partially shaded by surrounding buildings, but the effects of this within-roof spatial environmental heterogeneity on thermal performance and other ecosystem services have not been examined. We quantified the effects of spatial heterogeneity in solar radiation, substrate depth and other variables affected by these drivers on vegetation and ecosystem services in an extensive green roof. Spatial heterogeneity in substrate depth and insolation were correlated with differential growth, survival and flowering in two focal plant species. These effects were likely driven by the resulting spatial heterogeneity in substrate temperature and moisture content. Thermal performance (indicated by heat flux and substrate temperature) was influenced by spatial heterogeneity in vegetation cover and substrate depth. Areas with less insolation were cooler in summer and had greater substrate moisture, leading to more favorable conditions for plant growth and survival. Spatial variation in substrate moisture (7%-26% volumetric moisture content) and temperature (21°C-36°C) during hot sunny conditions in summer could cause large differences in stormwater retention and heat flux within a single green roof. Shaded areas promote smaller heat fluxes through the roof, leading to energy savings, but lower evapotranspiration in these areas should reduce stormwater retention capacity. Spatial heterogeneity can thus result in trade-offs between different ecosystem services. The effects of these spatial heterogeneities are likely widespread in green roofs. Structures that provide shelter from sun and wind may be productively utilized to design higher functioning green roofs and increase biodiversity by providing habitat
Podivilov, Evgeniy V; Bednyakova, Anastasia E; Fedoruk, Mikhail P; Babin, Sergey A
2016-01-01
Dissipative solitons are stable localized coherent structures with linear frequency chirp generated in normal-dispersion mode-locked lasers. The soliton energy in fiber lasers is limited by the Raman effect, but implementation of intracavity feedback for the Stokes wave enables synchronous generation of a coherent Raman dissipative soliton. Here we demonstrate a new approach for generating chirped pulses at new wavelengths by mixing in a highly-nonlinear fiber of two frequency-shifted dissipative solitons, as well as cascaded generation of their clones forming a "dissipative soliton comb" in the frequency domain. We observed up to eight equidistant components in a 400-nm interval demonstrating compressibility from ~10 ps to ~300 fs. This approach, being different from traditional frequency combs, can inspire new developments in fundamental science and applications.
Entanglement generated by dissipation
Krauter, Hanna; Jensen, Kasper; Wasilewski, Wojciech; Petersen, Jonas M; Cirac, J Ignacio; Polzik, Eugene S
2010-01-01
Entanglement is not only one of the most striking features of Quantum Mechanics but also an essential ingredient in most applications in the field of Quantum Information. Unfortunately, this property is very fragile. In experiments conducted so far, coupling of the system to a quantum mechanical environment, commonly referred to as dissipation, either inhibits entanglement or prevents its generation. In this Letter, we report on an experiment in which dissipation induces entanglement between two atomic objects rather than impairing it. This counter-intuitive effect is achieved by engineering the dissipation by means of laser- and magnetic fields, and leads to entanglement which is very robust and therefore long-lived. Our system consists of two distant macroscopic ensembles containing about 10^{12} atoms coupled to the environment composed of the vacuum modes of the electromagnetic field. The two atomic objects are kept entangled by dissipation at room temperature for about 0.015s. The prospects of using this...
Abdel-Wahed, Mohamed; Akl, Mohamed
2016-09-01
Analysis of the MHD Nanofluid boundary layer flow over a rotating disk with a constant velocity in the presence of hall current and non-linear thermal radiation has been covered in this work. The variation of viscosity and thermal conductivity of the fluid due to temperature and nanoparticles concentration and size is considered. The problem described by a system of P.D.E that converted to a system of ordinary differential equations by the similarity transformation technique, the obtained system solved analytically using Optimal Homotopy Asymptotic Method (OHAM) with association of mathematica program. The velocity profiles and temperature profiles of the boundary layer over the disk are plotted and investigated in details. Moreover, the surface shear stress, rate of heat transfer explained in details.
Dissipation in Relativistic Pair-Plasma Reconnection
Hesse, Michael; Zenitani, Seiji
2007-01-01
We present an investigation of the relativistic dissipation in magnetic reconnection. The investigated system consists of an electron-positron plasma. A relativistic generalization of Ohm's law is derived. We analyze a set of numerical simulations, composed of runs with and without guide magnetic field, and of runs with different species temperatures. The calculations indicate that the thermal inertia-based dissipation process survives in relativistic plasmas. For anti-parallel reconnection, it is found that the pressure tensor divergence remains the sole contributor to the reconnection electric field, whereas relativistic guide field reconnection exhibits a similarly important role of the bulk inertia terms.
Directory of Open Access Journals (Sweden)
Machireddy Gnaneswara Reddy
2014-01-01
Full Text Available A two-dimensional mathematical model is presented for the laminar heat and mass transfer of an electrically-conducting, viscous and Joule (Ohmic heating fluid over an inclined radiate isothermal permeable surface in the presence of the variable thermal conductivity, thermophoresis and heat generation. The Talbot- Cheng-Scheffer-Willis formulation (1980 is used to introduce a thermophoretic coefficient into the concentration boundary layer equation. The governing partial differential equations are non-dimensionalized and transformed into a system of nonlinear ordinary differential similarity equations, in a single independent variable . The resulting coupled nonlinear equations are solved under appropriate transformed boundary conditions using the Runge-Kutta fourth order along with shooting method. Comparisons with previously published work are performed and the results are found to be in very good agreement. Computations are performed for a wide range of the governing flow parameters, viz., magnetic field parameter, thermophoretic coefficient (a function of Knudsen number, Eckert number (viscous heating effect, angle of inclination, thermal conductivity parameter, heat generation parameter and Schmidt number. The present problem finds applications in optical fiber fabrication, aerosol filter precipitators, particle deposition on hydronautical blades, semiconductor wafer design, thermo-electronics and magnetohydrodynamic energy generators.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Based on entransy dissipation, the mean temperature difference of solenoid (electromagnet) with high thermal conductivity material inserted is deduced, which can be taken as the fundament for heat transfer optimization using the extremum principle of entransy dissipation. Then, the electromagnet working at steady state (constant magnetic field, constant heat generating rate per unit volume) is optimized for entransy dissipation minimization (i.e. mean temperature difference minimization) with and without volume constraint. Besides, the effect of high thermal conductivity material on the magnetic field is analyzed, and the minimum mean temperature versus volume and magnetic induction characteristic are also studied.
Institute of Scientific and Technical Information of China (English)
张高胜; 丁晓红; 周吉
2015-01-01
在制造锂电池时，设定方法来估算锂电池内部温度是十分必要的。电池模块解决的主要问题是：保持电池模块内单体电池之间一致恒定的温度，避免达到电池本身所要求的温度峰值，引起电池性能的恶化及安全问题。通过单体电池的电化学反应来估算电池的热产生率，为实现这一目的，进行充放电实验来获得电池放电过程中的特性参数。测试是在恒温下进行，模拟仿真设置条件为恒温，自然对流。热产生率是通过热模型方程进行计算的。随后证实热模型的有效性，并将该模型进行简单的散热分析，得出增大空气对流系数可以明显降低温度，这为以后的散热分析奠定了基础。%It is very necessary to set the method to estimate internal temperature of the lithium battery when making lithium battery.The main problems of the battery module are:keep consistent constant temperature between single battery of the battery module,avoid reaching the peak temperature required by the battery itself,causing the worsening of battery performance and safety issue.Through single battery electrochemistry reaction to estimate heat generation rate of battery power,in order to achieve this aim,taking the charging and discharging experiment to obtain the characteristic parameter in the discharging process.Test was conducted under constant temperature,simulation setting constant temperature,natural convection.Through thermal model calculate heat power.Then verify the valid of the thermal model and take the model for simple thermal analysis,conclude that increasing the air convection coefficient can reduce the temperature obviously,which laid the foundation for later heat analysis.
Zhang, Yanwen; Stocks, G. Malcolm; Jin, Ke; Lu, Chenyang; Bei, Hongbin; Sales, Brian C.; Wang, Lumin; Béland, Laurent K.; Stoller, Roger E.; Samolyuk, German D.; Caro, Magdalena; Caro, Alfredo; Weber, William J.
2015-10-01
A grand challenge in materials research is to understand complex electronic correlation and non-equilibrium atomic interactions, and how such intrinsic properties and dynamic processes affect energy transfer and defect evolution in irradiated materials. Here we report that chemical disorder, with an increasing number of principal elements and/or altered concentrations of specific elements, in single-phase concentrated solid solution alloys can lead to substantial reduction in electron mean free path and orders of magnitude decrease in electrical and thermal conductivity. The subsequently slow energy dissipation affects defect dynamics at the early stages, and consequentially may result in less deleterious defects. Suppressed damage accumulation with increasing chemical disorder from pure nickel to binary and to more complex quaternary solid solutions is observed. Understanding and controlling energy dissipation and defect dynamics by altering alloy complexity may pave the way for new design principles of radiation-tolerant structural alloys for energy applications.
Dissipative structures and chaos
Mori, Hazime
1998-01-01
This monograph consists of two parts and gives an approach to the physics of open nonequilibrium systems. Part I derives the phenomena of dissipative structures on the basis of reduced evolution equations and includes Bénard convection and Belousov-Zhabotinskii chemical reactions. Part II discusses the physics and structures of chaos. While presenting a construction of the statistical physics of chaos, the authors unify the geometrical and statistical descriptions of dynamical systems. The shape of chaotic attractors is characterized, as are the mixing and diffusion of chaotic orbits and the fluctuation of energy dissipation exhibited by chaotic systems.
International Nuclear Information System (INIS)
A two-dimensional mathematical model is presented for the laminar heat and mass transfer of an electrically-conducting, heat generating/absorbing fluid past a perforated horizontal surface in the presence of viscous and Joule (Ohmic) heating. The Talbot-Cheng-Scheffer-Willis formulation (1980) is used to introduce a thermophoretic coefficient into the concentration boundary layer equation. The governing partial differential equations are non-dimensionalized and transformed into a system of nonlinear ordinary differential similarity equations, in a single independent variable, η. The resulting coupled, nonlinear equations are solved under appropriate transformed boundary conditions using the Network Simulation Method. Computations are performed for a wide range of the governing flow parameters, viz Prandtl number, thermophoretic coefficient (a function of Knudsen number), Eckert number (viscous heating effect), thermal conductivity parameter, heat absorption/generation parameter, wall transpiration parameter, Hartmann number and Schmidt number. The numerical details are discussed with relevant applications. Excellent correlation is achieved with earlier studies due to White (1974) and Chamkha and Issa (2000). The present problem finds applications in optical fiber fabrication, aerosol filter precipitators, particle deposition on hydronautical blades, semiconductor wafer design, thermo-electronics and nuclear hazards.
Dissipation Bound for Thermodynamic Control
Machta, Benjamin B.
2015-12-01
Biological and engineered systems operate by coupling function to the transfer of heat and/or particles down a thermal or chemical gradient. In idealized deterministically driven systems, thermodynamic control can be exerted reversibly, with no entropy production, as long as the rate of the protocol is made slow compared to the equilibration time of the system. Here we consider fully realizable, entropically driven systems where the control parameters themselves obey rules that are reversible and that acquire directionality in time solely through dissipation. We show that when such a system moves in a directed way through thermodynamic space, it must produce entropy that is on average larger than its generalized displacement as measured by the Fisher information metric. This distance measure is subextensive but cannot be made small by slowing the rate of the protocol.
Collective variables and dissipation
International Nuclear Information System (INIS)
This course is an introduction to some basic concepts of non-equilibrium statistical mechanics. We put stress on the relevant entropy associated to a set of collective variables, on the meaning of the projection method in Liouville space and its use to establish equations of motion for these variables, and on the interpretation of dissipation in the framework of information theory
Thermal syneresis affected by heating schedule and moisture level in surimi gels.
Park, Y D; Yoon, K S; Lee, C M
2008-03-01
The extent of thermal syneresis in protein gelation is indicative of thermal and freeze-thaw stability as well as the network integrity of a protein gel. Thermal syneresis in Alaska pollock surimi gels was examined under different heating schedules (40 degrees C/20 min to 90 degrees C/30 min, 60 degrees C/20 min to 90 degrees C/30 min, and 90 degrees C/20 min to 90 degrees C/20 min) at varying moisture levels (80%, 82%, and 84%). The extent of syneresis and gel firming was monitored by centrifugation expressible moisture and penetration force, respectively. The occurrence of 2 distinct peaks as a function of time for both thermal syneresis and gel firming suggests that a multistage aggregation is involved in the formation of gel network. All syneresis preceded gel firming upon protein aggregation. Increasing the moisture content in the gel delayed the 2nd stage of protein aggregation. The 60 degrees C/20 min preheating followed by 90 degrees C/30 min postheating resulted in significantly greater thermal syneresis and gel weakening compared to 40 and 90 degrees C preheating. Changes of gel structure clearly reflected thermal syneresis when the size of water pores became smaller with initiation of network formation and progressively larger upon further heating. Thermal syneresis history during protein gelation can be used to predict thermal and freeze-thaw stability.
The possibility estimation of the thermal underwater affected by industrial enterprises for using
Directory of Open Access Journals (Sweden)
Zholudev S.V.
2015-09-01
Full Text Available The analysis of hydrodynamic features of the heated underwater is in process conducted and it is well-proven that water of thermal area of high temperature industrial objects has high enough thermal parameters and can be used in the well-known heat-pumping and soil heat accumulators technologies with minimum modifications.
Advanced thermal management materials for concentrator photovoltaic arrays
Zweben, Carl
2010-08-01
Thermal management is a critical issue for photovoltaics (PVs), especially concentrator photovoltaic systems. Thermal management problems are similar for all semiconductors, including those used in microelectronics and other optoelectronic applications, such as lasers, light-emitting diodes (LEDs), detectors and displays. We divide the thermal management problem into two parts: heat dissipation and thermal stresses. Heat dissipation affects efficiency and lifetime. Thermal stresses affect manufacturing yield and lifetime. Traditional thermal management materials all have serious deficiencies. Copper and aluminum have high coefficients of thermal expansion (CTEs), which can cause severe thermal stresses during manufacturing and in service. Compliant attach materials, used to minimize thermal stresses, all have major drawbacks. Traditional low-CTE thermal management materials have relatively low thermal conductivities and are hard to machine. In response to these deficiencies, new thermal management materials have been, and are continuing to be developed, which have low CTEs and thermal conductivities up to four times that of copper. Some are reportedly are cheaper than copper. In this paper, we survey the six categories of advanced thermal materials, including properties, state of maturity and cost. We also review a CPV application in which an advanced metal matrix composite with a tailored CTE eliminated solder joint failure and provided other benefits.
Analysis of the factors affecting thermal evolution of hot rolled steel during coil cooling
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The thermal evolution of steel coil during cooling was simulated and investigated by the use of in-house Q-CSP(R) software.The dependence of the thermal evolution of steel coil on cooling methods, temperature distribution of the strip before coiling, coil size and steel grades was also discussed.The study plays a significant role in helping steel makers to better understand and control the cooling process.
Institute of Scientific and Technical Information of China (English)
杨爱波; 陈林根; 谢志辉; 孙丰瑞
2015-01-01
Constructal optimization of a rectangular fin heat sink with two-dimensional heat transfer model is carried out through using numerical simulation by finite element method, in which the minimized maximum thermal resistance and the minimized equivalent thermal resistance based on entransy dissipation are taken as the optimization objectives, respectively. The optimal constructs based on the two objectives are compared. The influences of a global parameter (a) which integrates convective heat transfer coeﬃcient, overall area occupied by fin and its thermal conductivity, and the volume fraction (ϕ), on the minimized maximum thermal resistance, the minimized equivalent thermal resistances and their corresponding optimal constructs are analyzed. The results show that there does not exist optimal thickness of fins for the two objectives when the shape of the heat sink is fixed, and the optimal constructs based on the two objectives are different when the shape of the heat sinks can be changed freely. Besides, the global parameter has no influence on the optimal constructs based on the two objectives, but the volume fraction does. The increases of the global parameter and the volume fraction reduce the minimum values of the maximum thermal resistance and the equivalent thermal resistance, but the degrees are different. The reduce degree of the global parameter to the minimized equivalent thermal resistance is larger than that to the minimized maximum thermal resistance. The minimized equivalent thermal resistance and the minimized maximum thermal resistance are reduced by 40.03%and 41.42%for a=0.5, respectively, compared with those for a = 0.3. However, the reduce degree of the volume fraction to the minimized maximum thermal resistance is larger than that to the minimized equivalent thermal resistance. The minimized equivalent thermal resistance and the minimized maximum thermal resistance are reduced by 59.69%and 32.80%forϕ=0.4, respectively, compared with those for
Debus, J -D; Succi, S; Herrmann, H J
2015-01-01
By inspecting the effect of curvature on a moving fluid, we find that local sources of curvature not only exert inertial forces on the flow, but also generate viscous stresses as a result of the departure of streamlines from the idealized geodesic motion. The curvature-induced viscous forces are shown to cause an indirect and yet appreciable energy dissipation. As a consequence, the flow converges to a stationary equilibrium state solely by virtue of curvature-induced dissipation. In addition, we show that flow through randomly-curved media satisfies a non-linear transport law, resembling Darcy-Forchheimer's law, due to the viscous forces generated by the spatial curvature. It is further shown that the permeability can be characterized in terms of the average metric perturbation.
Quantum dissipative Higgs model
Energy Technology Data Exchange (ETDEWEB)
Amooghorban, Ehsan, E-mail: Ehsan.amooghorban@sci.sku.ac.ir; Mahdifar, Ali, E-mail: mahdifar_a@sci.sku.ac.ir
2015-09-15
By using a continuum of oscillators as a reservoir, we present a classical and a quantum-mechanical treatment for the Higgs model in the presence of dissipation. In this base, a fully canonical approach is used to quantize the damped particle on a spherical surface under the action of a conservative central force, the conjugate momentum is defined and the Hamiltonian is derived. The equations of motion for the canonical variables and in turn the Langevin equation are obtained. It is shown that the dynamics of the dissipative Higgs model is not only determined by a projected susceptibility tensor that obeys the Kramers–Kronig relations and a noise operator but also the curvature of the spherical space. Due to the gnomonic projection from the spherical space to the tangent plane, the projected susceptibility displays anisotropic character in the tangent plane. To illuminate the effect of dissipation on the Higgs model, the transition rate between energy levels of the particle on the sphere is calculated. It is seen that appreciable probabilities for transition are possible only if the transition and reservoir’s oscillators frequencies to be nearly on resonance.
Heat conduction modelling with energy conservation dissipative particle dynamics
International Nuclear Information System (INIS)
The paper studies by means of numerical simulations the model of dissipative particle dynamics with energy conservation for the simple case of thermal conduction. The model can be understood as a versatile discretization of the heat conduction equation on a random lattice including thermal fluctuations
Nuruddin, Ibrahim K.
2012-01-01
This research is aimed at understanding the effect of thermal cycles on the metallurgical and microstructural characteristics of the heat affected zone of a multi-pass pipeline weld. Continuous Cooling Transformation (CCT) diagrams of the pipeline steel grades studied (X65, X70 and X100) were generated using a thermo mechanical simulator (Gleeble 3500) and 10 mm diameter by 100 mm length samples. The volume change during phase transformation was studied by a dilatometer, this is to underst...
International Nuclear Information System (INIS)
A long-standing objective in materials research is to understand how energy is dissipated in both the electronic and atomic subsystems in irradiated materials, and how related non-equilibrium processes may affect defect dynamics and microstructure evolution. Here we show that alloy complexity in concentrated solid solution alloys having both an increasing number of principal elements and altered concentrations of specific elements can lead to substantial reduction in the electron mean free path and thermal conductivity, which has a significant impact on energy dissipation and consequentially on defect evolution during ion irradiation. Enhanced radiation resistance with increasing complexity from pure nickel to binary and to more complex quaternary solid solutions is observed under ion irradiation up to an average damage level of 1 displacement per atom. Understanding how materials properties can be tailored by alloy complexity and their influence on defect dynamics may pave the way for new principles for the design of radiation tolerant structural alloys
Thermal behaviour of a periodic structure supported by dielectric rods in vacuum
Gahlaut, V.; Alvi, P. A.; Ghosh, S.
2014-06-01
In a traveling-wave tube (TWT) the helical periodic slow-wave structure (SWS) is supported by dielectric supports in a metal envelope in high vacuum. The heat generated in the helix during beam-wave interaction, restricts the average power handling capability of a TWT, dissipated by conduction through support rods. Thermal contact resistances, arises at different joints of different materials, affect heat dissipation from the helix which have been studied and presented here.
McCue, Marshall D; Voigt, Christian C; Jefimow, Małgorzata; Wojciechowski, Michał S
2014-11-01
During acclimatization to winter, changes in morphology and physiology combined with changes in diet may affect how animals use the nutrients they ingest. To study (a) how thermal acclimation and (b) nutritional history affect the rates at which Siberian hamsters (Phodopus sungorus) oxidize different classes of dietary nutrients, we conducted two trials in which we fed hamsters one of three (13) C-labeled compounds, that is, glucose, leucine, or palmitic acid. We predicted that under acute cold stress (3 hr at 2°C) hamsters previously acclimated to cold temperatures (10°C) for 3 weeks would have higher resting metabolic rate (RMR) and would oxidize a greater proportion of dietary fatty acids than animals acclimated to 21°C. We also investigated how chronic nutritional stress affects how hamsters use dietary nutrients. To examine this, hamsters were fed four different diets (control, low protein, low lipid, and low-glycemic index) for 2 weeks. During cold challenges, hamsters previously acclimated to cold exhibited higher thermal conductance and RMR, and also oxidized more exogenous palmitic acid during the postprandial phase than animals acclimated to 21°C. In the nutritional stress trial, hamsters fed the low protein diet oxidized more exogenous glucose, but not more exogenous palmitic acid than the control group. The use of (13) C-labeled metabolic tracers combined with breath testing demonstrated that both thermal and nutritional history results in significant changes in the extent to which animals oxidize dietary nutrients during the postprandial period.
Relative Entropy, Interaction Energy and the Nature of Dissipation
Directory of Open Access Journals (Sweden)
Bernard Gaveau
2014-06-01
Full Text Available Many thermodynamic relations involve inequalities, with equality if a process does not involve dissipation. In this article we provide equalities in which the dissipative contribution is shown to involve the relative entropy (a.k.a. Kullback-Leibler divergence. The processes considered are general time evolutions both in classical and quantum mechanics, and the initial state is sometimes thermal, sometimes partially so. By calculating a transport coefficient we show that indeed—at least in this case—the source of dissipation in that coefficient is the relative entropy.
Efficient Simulation of Dissipative Dynamics
Noh, Kyungjoo; Albert, Victor V.; Shen, Chao; Jiang, Liang
Open quantum systems with engineered dissipations may have more than one steady states. These steady states may form a non-trivial decoherence free subspace (DFS) that can store quantum information against major decoherences. Besides unitary operations within DFS, it is also useful to have dissipative/cooling operations within the DFS. We investigate the possibility of using Hamiltonian perturbation to the engineered dissipation to induce an effective dissipative dynamics within the DFS in a controlled manner. The major challenge is to simulate all the Lindblad jump operators in the master equation. By designing the dissipation within the subspace complementary to the DFS, we can simply use the Hamiltonian perturbation to the designed dissipation with a single jump operator to produce an effective dissipation with multiple Lindblad jump operators.
Climate change affects marine fishes through the oxygen limitation of thermal tolerance.
Pörtner, Hans O; Knust, Rainer
2007-01-01
A cause-and-effect understanding of climate influences on ecosystems requires evaluation of thermal limits of member species and of their ability to cope with changing temperatures. Laboratory data available for marine fish and invertebrates from various climatic regions led to the hypothesis that, as a unifying principle, a mismatch between the demand for oxygen and the capacity of oxygen supply to tissues is the first mechanism to restrict whole-animal tolerance to thermal extremes. We show in the eelpout, Zoarces viviparus, a bioindicator fish species for environmental monitoring from North and Baltic Seas (Helcom), that thermally limited oxygen delivery closely matches environmental temperatures beyond which growth performance and abundance decrease. Decrements in aerobic performance in warming seas will thus be the first process to cause extinction or relocation to cooler waters. PMID:17204649
Direct and indirect detection of dissipative dark matter
International Nuclear Information System (INIS)
We study the constraints from direct detection and solar capture on dark matter scenarios with a subdominant dissipative component. This dissipative dark matter component in general has both a symmetric and asymmetric relic abundance. Dissipative dynamics allow this subdominant dark matter component to cool, resulting in its partial or total collapse into a smaller volume inside the halo (e.g., a dark disk) as well as a reduced thermal velocity dispersion compared to that of normal cold dark matter. We first show that these features considerably relax the limits from direct detection experiments on the couplings between standard model (SM) particles and dissipative dark matter. On the other hand, indirect detection of the annihilation of the symmetric dissipative dark matter component inside the Sun sets stringent and robust constraints on the properties of the dissipative dark matter. In particular, IceCube observations force dissipative dark matter particles with mass above 50 GeV to either have a small coupling to the SM or a low local density in the solar system, or to have a nearly asymmetric relic abundance. Possible helioseismology signals associated with purely asymmetric dissipative dark matter are discussed, with no present constraints
Dissipation regimes for short wind waves
Caulliez, Guillemette
2013-02-01
The dissipation processes affecting short wind waves of centimeter and decimeter scales are investigated experimentally in laboratory. The processes include damping due to molecular viscosity, generation of capillary waves, microbreaking, and breaking. The observations were made in a large wind wave tank for a wide range of fetches and winds, using a laser sheet and a high-resolution video camera. The work aims at constructing a comprehensive picture of dissipative processes in the short wind wave field, to find for which scales particular dissipative mechanism may become important. Four distinct regimes have been identified. For capillary-gravity wave fields, i.e., for dominant waves with scales below 4 cm, viscous damping is found to be the main dissipation mechanism. The gravity-capillary wave fields with dominant wavelength less than 10 cm usually exhibit a train of capillary ripples at the crest wavefront, but no wave breaking. For such waves, the main dissipation process is molecular viscosity occurring through nonlinear energy cascade toward high-frequency motions. Microscale breaking takes place for waves longer than 10 cm and manifests itself in a very localized surface disruption on the forward face of the crest. Such events generate turbulent motions in water and thus enhance wave dissipation. Plunging breaking, characterized by formation of a crest bulge, a microjet hitting the water surface and a splash-up, occurs for short gravity waves of wavelength exceeding 20 cm. Macroscale spilling breaking is also observed for longer waves at high winds. In both cases, the direct momentum transfer from breaking waves to the water flow contributes significantly to wave damping.
Kalashnikov, Vladimir L
2010-01-01
The analytical theory of chirped dissipative soliton solutions of nonlinear complex Ginzburg-Landau equation is exposed. Obtained approximate solutions are easily traceable within an extremely broad range of the equation parameters and allow a clear physical interpretation as a representation of the strongly chirped pulses in mode-locked both solid-state and fiber oscillators. Scaling properties of such pulses demonstrate a feasibility of sub-mJ pulse generation in the continuous-wave mode-locking regime directly from an oscillator operating at the MHz repetition rate.
International Nuclear Information System (INIS)
The various incidents, imputed to thermal fatigue, which occurred throughout the world on the auxiliary lines of Reactor Coolant System (SIS, RHR, CVC), led EDF to urge a research program in order to determine the origins and the consequences of these problems for the French nuclear power plants. In 1992, following the crossing crack discovered at Dampierre 2 on the un-isolable part of a Safety Injection System pipe, a program of instrumentation was defined and is described in this paper. Among the objectives, two of the principal goals were to determine the thermal loadings really supported by the various lines and to highlight the thermal hydraulic phenomena affecting them. Indeed, in order to explain the discovered damages, it was essential to know the real thermal loadings to compare them with those of design and to carry out mechanical calculations of resistance to thermal fatigue. The instrumentations installed on the 900 MW units enabled to check the resistance with the fatigue of all the auxiliary lines in spite of significant differences between the real loadings and those envisaged at the design. They contributed to the knowledge improvement on the local thermal hydraulic phenomena but the incidents at Dampierre 1 showed that this knowledge is still imperfect. The results of these instrumentations are also used for the design of the future units by the use of the feedback of several cycles of acquisition on the 900 MW units, but also 1300 MW and 1450 MW since similar instrumentations were installed on the auxiliary lines in Golfech 2 and Chooz B1
Heat flux and quantum correlations in dissipative cascaded systems
Lorenzo, Salvatore; Farace, Alessandro; Ciccarello, Francesco; Palma, G. Massimo; Giovannetti, Vittorio
2015-02-01
We study the dynamics of heat flux in the thermalization process of a pair of identical quantum systems that interact dissipatively with a reservoir in a cascaded fashion. Despite that the open dynamics of the bipartite system S is globally Lindbladian, one of the subsystems "sees" the reservoir in a state modified by the interaction with the other subsystem and hence it undergoes a non-Markovian dynamics. As a consequence, the heat flow exhibits a nonexponential time behavior which can greatly deviate from the case where each party is independently coupled to the reservoir. We investigate both thermal and correlated initial states of S and show that the presence of correlations at the beginning can considerably affect the heat-flux rate. We carry out our study in two paradigmatic cases—a pair of harmonic oscillators with a reservoir of bosonic modes and two qubits with a reservoir of fermionic modes—and compare the corresponding behaviors. In the case of qubits and for initial thermal states, we find that the trace distance discord is at any time interpretable as the correlated contribution to the total heat flux.
Thermal treatment of bentonite reduces aflatoxin b1 adsorption and affects stem cell death.
Nones, Janaína; Nones, Jader; Riella, Humberto Gracher; Poli, Anicleto; Trentin, Andrea Gonçalves; Kuhnen, Nivaldo Cabral
2015-10-01
Bentonites are clays that highly adsorb aflatoxin B1 (AFB1) and, therefore, protect human and animal cells from damage. We have recently demonstrated that bentonite protects the neural crest (NC) stem cells from the toxicity of AFB1. Its protective effects are due to the physico-chemical properties and chemical composition altered by heat treatment. The aim of this study is to prepare and characterize the natural and thermal treatments (125 to 1000 °C) of bentonite from Criciúma, Santa Catarina, Brazil and to investigate their effects in the AFB1 adsorption and in NC cell viability after challenging with AFB1. The displacement of water and mineralogical phases transformations were observed after the thermal treatments. Kaolinite disappeared at 500 °C and muscovite and montmorillonite at 1000 °C. Slight changes in morphology, chemical composition, and density of bentonite were observed. The adsorptive capacity of the bentonite particles progressively reduced with the increase in temperature. The observed alterations in the structure of bentonite suggest that the heat treatments influence its interlayer distance and also its adsorptive capacity. Therefore, bentonite, even after the thermal treatment (125 to 1000 °C), is able to increase the viability of NC stem cells previously treated with AFB1. Our results demonstrate the effectiveness of bentonite in preventing the toxic effects of AFB1.
Generalized global symmetries and dissipative magnetohydrodynamics
Grozdanov, Sašo; Iqbal, Nabil
2016-01-01
The conserved magnetic flux of U(1) electrodynamics coupled to matter in four dimensions is associated with a generalized global symmetry. We study the realization of such a symmetry at finite temperature and develop the hydrodynamic theory describing fluctuations of a conserved 2-form current around thermal equilibrium. This can be thought of as a systematic derivation of relativistic magnetohydrodynamics, constrained only by symmetries and effective field theory. We construct the entropy current and show that at first order in derivatives, there are six dissipative transport coefficients. We present a universal definition of resistivity in a theory of dynamical electromagnetism and derive a direct Kubo formula for the resistivity in terms of correlation functions of the electric field operator. We also study fluctuations and collective modes, deriving novel expressions for the dissipative widths of magnetosonic and Alfven modes. Finally, we demonstrate that a non-trivial truncation of the theory can be perf...
Viscosity measurement techniques in Dissipative Particle Dynamics
Boromand, Arman; Jamali, Safa; Maia, Joao M.
2015-11-01
In this study two main groups of viscosity measurement techniques are used to measure the viscosity of a simple fluid using Dissipative Particle Dynamics, DPD. In the first method, a microscopic definition of the pressure tensor is used in equilibrium and out of equilibrium to measure the zero-shear viscosity and shear viscosity, respectively. In the second method, a periodic Poiseuille flow and start-up transient shear flow is used and the shear viscosity is obtained from the velocity profiles by a numerical fitting procedure. Using the standard Lees-Edward boundary condition for DPD will result in incorrect velocity profiles at high values of the dissipative parameter. Although this issue was partially addressed in Chatterjee (2007), in this work we present further modifications (Lagrangian approach) to the original LE boundary condition (Eulerian approach) that will fix the deviation from the desired shear rate at high values of the dissipative parameter and decrease the noise to signal ratios in stress measurement while increases the accessible low shear rate window. Also, the thermostat effect of the dissipative and random forces is coupled to the dynamic response of the system and affects the transport properties like the viscosity and diffusion coefficient. We investigated thoroughly the dependency of viscosity measured by both Eulerian and Lagrangian methodologies, as well as numerical fitting procedures and found that all the methods are in quantitative agreement.
Holloway, J.M.; Nordstrom, D.K.; Böhlke, J.K.; McCleskey, R.B.; Ball, J.W.
2011-01-01
Dissolved inorganic nitrogen, largely in reduced form (NH4(T)≈NH4(aq)++NH3(aq)o), has been documented in thermal waters throughout Yellowstone National Park, with concentrations ranging from a few micromolar along the Firehole River to millimolar concentrations at Washburn Hot Springs. Indirect evidence from rock nitrogen analyses and previous work on organic compounds associated with Washburn Hot Springs and the Mirror Plateau indicate multiple sources for thermal water NH4(T), including Mesozoic marine sedimentary rocks, Eocene lacustrine deposits, and glacial deposits. A positive correlation between NH4(T) concentration and δ18O of thermal water indicates that boiling is an important mechanism for increasing concentrations of NH4(T) and other solutes in some areas. The isotopic composition of dissolved NH4(T) is highly variable (δ15N = −6‰ to +30‰) and is positively correlated with pH values. In comparison to likely δ15N values of nitrogen source materials (+1‰ to +7‰), high δ15N values in hot springs with pH >5 are attributed to isotope fractionation associated with NH3(aq)o loss by volatilization. NH4(T) in springs with low pH typically is relatively unfractionated, except for some acid springs with negative δ15N values that are attributed to NH3(g)o condensation. NH4(T) concentration and isotopic variations were evident spatially (between springs) and temporally (in individual springs). These variations are likely to be reflected in biomass and sediments associated with the hot springs and outflows. Elevated NH4(T) concentrations can persist for 10s to 1000s of meters in surface waters draining hot spring areas before being completely assimilated or oxidized.
Elementary Processes in Dissipative Cosmic Medium
Yoshimura, M
1997-01-01
Quantum dynamics of a finite degrees of freedom is often much affected by interaction with the larger environment of cosmic medium. In this lecture we first review some recent developments of the theory of quantum dissipation in the linear open system. In the second part we discuss two classes of applications: decay of unstable particle in medium, and environmental effect on the parametric particle production. The first subject of particle decay may have important consequences on the scenario...
Influence of queue propagation and dissipation on route travel times
DEFF Research Database (Denmark)
Raovic, Nevena
into account (Bliemer, 2008). Yperman (2007) indicates that there is a significant difference in queue-propagation and queue-dissipation between the LTM and DQM. This results in different route travel times, and can further affect route choice. In this paper, different approaches to represent queue propagation...... and dissipation through the CTM, LTM and DQM are studied. A simple network allows to show how these approaches influence route travel time. Furthermore, the possibility of changing the existing DQM is considered in order to more realistically represent queue propagation and dissipation, which would lead to more...... accurate route travel times....
Mariana Ferreira Oliveira Prates; Raquel Pires Campos; Michelly Morais Barbosa da Silva; Maria Lígia Rodrigues Macedo; Priscila Aiko Hiane; Manoel Mendes Ramos Filho
2015-01-01
The effect of jelly processing on the chemical properties, nutrients, antinutritional factors, bioactive compounds, and antioxidant activity of unripe and ripe canjiqueira fruits was evaluated. The fruits were collected from Pantanal regions at two different ripening stages and were used to produce jellies. The processing affected the chemical characteristics and the content of all nutrients, except for the lipids. Moisture and protein content reduced, whereas the energy value increased. The ...
Yuyama, Ikuko; Harii, Saki; Hidaka, Michio
2012-05-01
Reef-building corals harbor symbiotic dinoflagellates, Symbiodinium spp., which are currently divided into several clades. The responses of corals associated with different Symbiodinium clades to thermal stress are not well understood, especially at a gene expression level. Juveniles of the coral Acropora tenuis inoculated with different algal types (clade A or D) were exposed to thermal stress and the expression levels of four putative stress-responsive genes, including genes coding green and red fluorescent proteins, an oxidative stress-responsive protein, and an ascorbic acid transporter, were analyzed by quantitative real-time PCR. The expression levels of the four genes decreased at high temperatures if juveniles were associated with clade A symbionts but increased if the symbionts were in clade D. The intensity of green fluorescence increased with temperature in clade D symbionts harboring juveniles, but not in juveniles associated with clade A symbionts. The present results suggest that genotypes of endosymbiotic algae affect the thermal stress responses of the coral juveniles.
Heat flux dynamics in dissipative cascaded systems
de Lorenzo, S.; Farace, A.; Ciccarello, F.; De Palma, G; Giovannetti, V.
2014-01-01
We study the dynamics of heat flux in the thermalization process of a pair of identical quantum system that interact dissipatively with a reservoir in a {\\it cascaded} fashion. Despite the open dynamics of the bipartite system S is globally Lindbladian, one of the subsystems "sees" the reservoir in a state modified by the interaction with the other subsystem and hence it undergoes a non-Markovian dynamics. As a consequence, the heat flow exhibits a non-exponential time behaviour which can gre...
Aguilera, Yolanda; Esteban, Rosa M; Benítez, Vanesa; Mollá, Esperanza; Martín-Cabrejas, María A
2009-11-25
Changes in starch, functional, and microstructural characteristics that occurred in chickpea and lentil under soaking, cooking, and industrial dehydration processing were evaluated. Available starch in raw legumes represented 57-64%, and resistant starch (RS) is a significant component. As a result of cooking, available starch contents of soaked chickpea and lentil were significantly increased (21 and 12%, respectively) and RS decreased (65 and 49%, respectively) compared to raw flours. A similar trend was exhibited by dehydration, being more relevant in lentil (73% of RS decrease). The minimum nitrogen solubility of raw flours was at pH 3, and a high degree of protein insolubilization (80%) was observed in dehydrated flours. The raw legume flours exhibited low oil-holding capacities, 0.95-1.10 mL/g, and did not show any change by thermal processing, whereas water-holding capacities rose to 4.80-4.90 mL/g of sample. Emulsifying activity and foam capacity exhibited reductions as a result of cooking and industrial dehydration processing. The microstructural observations were consistent with the chemical results. Thus, the obtained cooked and dehydrated legume flours could be considered as functional ingredients for food formulation.
Piestun, Yogev; Yahav, Shlomo; Halevy, Orna
2015-10-01
Thermal manipulation (TM) of 39.5°C applied during mid-embryogenesis (embryonic d 7 to 16) has been proven to promote muscle development and enhance muscle growth and meat production in meat-type chickens. This study aimed to elucidate the cellular basis for this effect. Continuous TM or intermittent TM (for 12 h/d) increased myoblast proliferation manifested by higher (25 to 48%) myoblast number in the pectoral muscles during embryonic development but also during the first week posthatch. Proliferation ability of the pectoral-muscle-derived myoblasts in vitro was significantly higher in the TM treatments until embryonic d 15 (intermittent TM) or 13 (continuous TM) compared to that of controls, suggesting increased myogenic progeny reservoir in the muscle. However, the proliferation ability of myoblasts was lower in the TM treatments vs. control during the last days of incubation. This coincided with higher levels of myogenin expression in the muscle, indicating enhanced cell differentiation in the TM muscle. A similar pattern was observed posthatch: Myoblast proliferation was significantly higher in the TM chicks relative to controls during the peak of posthatch cell proliferation until d 6, followed by lower cell number 2 wk posthatch as myoblast number sharply decreases. Higher myogenin expression was observed in the TM chicks on d 6. This resulted in increased muscle growth, manifested by significantly higher relative weight of breast muscle in the embryo and posthatch. It can be concluded that temperature elevation during mid-term embryogenesis promotes myoblast proliferation, thus increasing myogenic progeny reservoir in the muscle, resulting in enhanced muscle growth in the embryo and posthatch.
Thermal conditions during juvenile development affect adult dispersal in a spider.
Bonte, Dries; Travis, Justin M J; De Clercq, Nele; Zwertvaegher, Ingrid; Lens, Luc
2008-11-01
Understanding the causes and consequences of dispersal is a prerequisite for the effective management of natural populations. Rather than treating dispersal as a fixed trait, it should be considered a plastic process that responds to both genetic and environmental conditions. Here, we consider how the ambient temperature experienced by juvenile Erigone atra, a spider inhabiting crop habitat, influences adult dispersal. This species exhibits 2 distinct forms of dispersal, ballooning (long distance) and rappelling (short distance). Using a half-sib design we raised individuals under 4 different temperature regimes and quantified the spiders' propensity to balloon and to rappel. Additionally, as an indicator of investment in settlement, we determined the size of the webs build by the spiders following dispersal. The optimal temperature regimes for reproduction and overall dispersal investment were 20 degrees C and 25 degrees C. Propensity to perform short-distance movements was lowest at 15 degrees C, whereas for long-distance dispersal it was lowest at 30 degrees C. Plasticity in dispersal was in the direction predicted on the basis of the risks associated with seasonal changes in habitat availability; long-distance ballooning occurred more frequently under cooler, spring-like conditions and short-distance rappelling under warmer, summer-like conditions. Based on these findings, we conclude that thermal conditions during development provide juvenile spiders with information about the environmental conditions they are likely to encounter as adults and that this information influences the spider's dispersal strategy. Climate change may result in suboptimal adult dispersal behavior, with potentially deleterious population level consequences. PMID:18974219
Heat Dissipation for Microprocessor Using Multiwalled Carbon Nanotubes Based Liquid
Directory of Open Access Journals (Sweden)
Bui Hung Thang
2013-01-01
Full Text Available Carbon nanotubes (CNTs are one of the most valuable materials with high thermal conductivity (2000 W/m·K compared with thermal conductivity of Ag 419 W/m·K. This suggested an approach in applying the CNTs in thermal dissipation system for high power electronic devices, such as computer processor and high brightness light emitting diode (HB-LED. In this work, multiwalled carbon nanotubes (MWCNTs based liquid was made by COOH functionalized MWCNTs dispersed in distilled water with concentration in the range between 0.2 and 1.2 gram/liter. MWCNT based liquid was used in liquid cooling system to enhance thermal dissipation for computer processor. By using distilled water in liquid cooling system, CPU’s temperature decreases by about 10°C compared with using fan cooling system. By using MWCNT liquid with concentration of 1 gram/liter MWCNTs, the CPU’s temperature decreases by 7°C compared with using distilled water in cooling system. Theoretically, we also showed that the presence of MWCNTs reduced thermal resistance and increased the thermal conductivity of liquid cooling system. The results have confirmed the advantages of the MWCNTs for thermal dissipation systems for the μ-processor and other high power electronic devices.
Heat dissipation for microprocessor using multiwalled carbon nanotubes based liquid.
Hung Thang, Bui; Trinh, Pham Van; Chuc, Nguyen Van; Khoi, Phan Hong; Minh, Phan Ngoc
2013-01-01
Carbon nanotubes (CNTs) are one of the most valuable materials with high thermal conductivity (2000 W/m · K compared with thermal conductivity of Ag 419 W/m · K). This suggested an approach in applying the CNTs in thermal dissipation system for high power electronic devices, such as computer processor and high brightness light emitting diode (HB-LED). In this work, multiwalled carbon nanotubes (MWCNTs) based liquid was made by COOH functionalized MWCNTs dispersed in distilled water with concentration in the range between 0.2 and 1.2 gram/liter. MWCNT based liquid was used in liquid cooling system to enhance thermal dissipation for computer processor. By using distilled water in liquid cooling system, CPU's temperature decreases by about 10°C compared with using fan cooling system. By using MWCNT liquid with concentration of 1 gram/liter MWCNTs, the CPU's temperature decreases by 7°C compared with using distilled water in cooling system. Theoretically, we also showed that the presence of MWCNTs reduced thermal resistance and increased the thermal conductivity of liquid cooling system. The results have confirmed the advantages of the MWCNTs for thermal dissipation systems for the μ -processor and other high power electronic devices.
Nanoscale resolution immersion scanning thermal microscopy
Tovee, Peter D
2013-01-01
Nanoscale thermal properties are becoming of extreme importance for modern electronic circuits that dissipate increasing power on the length scale of few tens of nanometers, and for chemical and physical properties sensors and biosensors using nanoscale sized features. While Scanning Thermal Microscopy (SThM) is known for its ability to probe thermal properties and heat generation with nanoscale resolution, until today it was perceived impossible to use it in the liquid environment due to dominating direct heat exchange between microfabricated thermal probe and surrounding liquid that would deteriorate spatial resolution. Nonetheless, our theoretical analysis of SThM in liquids showed that for certain design of SThM probe with resistive heater located near the probe tip, their thermal signal is only moderately affected, by less than half on immersion in a dodecane environment. More significantly, its spatial resolution, surprisingly, would remain practically unaffected, and the thermal contact between the tip...
Notari, Alessio
2016-01-01
We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\\frac{\\phi}{f_\\gamma} F \\tilde{F}$, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density $\\rho_R$, which which can lead to inflation without the need of a flat potential. We analyze the system, for momenta $k$ smaller than the cutoff $f_\\gamma$, including numerically the backreaction. We consider the evolution from a given static initial condition and explicitly show that, if $f_\\gamma$ is smaller than the field excursion $\\phi_0$ by about a factor of at least ${\\cal O} (20)$, there is a friction effect which turns on before that the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of...
Directory of Open Access Journals (Sweden)
Mariana Ferreira Oliveira Prates
2015-03-01
Full Text Available The effect of jelly processing on the chemical properties, nutrients, antinutritional factors, bioactive compounds, and antioxidant activity of unripe and ripe canjiqueira fruits was evaluated. The fruits were collected from Pantanal regions at two different ripening stages and were used to produce jellies. The processing affected the chemical characteristics and the content of all nutrients, except for the lipids. Moisture and protein content reduced, whereas the energy value increased. The phytic acid found in fresh fruits was eliminated after processing, and the trypsin inhibitors were reduced, especially in ripe fruits. Lectin activity was not verified in unripe and ripe fruits and jellies. The levels of bioactive compounds were reduced after jelly processing, but their retention was higher in unripe fruits. The final levels of bioactive compounds in the jelly made from unripe fruits were higher than that in the jelly made from ripe fruits, whereas the IC50 value was lower, indicating higher potential to prevent free radicals damages to human body. Jelly processing proved to be a good alternative to the use of canjiqueira fruits due to the reduction in antinutritional factors and the retention of bioactive compounds
Energy Technology Data Exchange (ETDEWEB)
He, Yanming, E-mail: heyanming@zjut.edu.cn [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Yang, Jianguo, E-mail: yangjg@zjut.edu.cn [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Qin, Chunjie [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Chen, Shuangjian [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Gao, Zengliang [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014 (China)
2015-09-15
Highlights: • The constitution of Ni–17Mo–7Cr alloy was convincingly ascertained by TEM analysis. • The Ni–17Mo–7Cr alloy was thermally cycled with a peak temperature up to 1350 °C. • The lamellar-like phases in the alloy were firstly determined by TEM and HRTEM. • The formation mechanism for the lamellar-like phases was unveiled rigorously. • Effect of lamellar-like phases on the alloy’s performances was evaluated in depth. - Abstract: A representative Ni–Mo–Cr superalloy with basic composition of Ni–17Mo–7Cr (wt.%) was fabricated in the work and the relationship between the microstructure and mechanical properties while it went through simulated heat-affected zone (HAZ) thermal cycle treatment was investigated. The results reveal that the Ni–Mo–Cr alloy mainly consisted of Ni matrix and MoC carbides. The critical peak temperature that a lamellar-like structure occurred in the alloy was found to be 1300 °C. These products were firstly characterized by transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) analysis, and they were essentially Ni matrix and carbides (MoC and chromium carbides) generated through local melting. The equivalent mechanical properties of the alloy relative to that of un-treated alloy were received owing to its unique architecture even the peak temperature during thermal cycle was up to 1350 °C. The results obtained suggests these lamellar-like products dispersed near the fusion line in a Ni–Mo–Cr welded joint will not influence the joint’s mechanical strength and stability while the peak temperature in the HAZ was adjusted below 1350 °C, providing valuable guideline in designing and applying the Ni–Mo–Cr system superalloys.
International Nuclear Information System (INIS)
Highlights: • The constitution of Ni–17Mo–7Cr alloy was convincingly ascertained by TEM analysis. • The Ni–17Mo–7Cr alloy was thermally cycled with a peak temperature up to 1350 °C. • The lamellar-like phases in the alloy were firstly determined by TEM and HRTEM. • The formation mechanism for the lamellar-like phases was unveiled rigorously. • Effect of lamellar-like phases on the alloy’s performances was evaluated in depth. - Abstract: A representative Ni–Mo–Cr superalloy with basic composition of Ni–17Mo–7Cr (wt.%) was fabricated in the work and the relationship between the microstructure and mechanical properties while it went through simulated heat-affected zone (HAZ) thermal cycle treatment was investigated. The results reveal that the Ni–Mo–Cr alloy mainly consisted of Ni matrix and MoC carbides. The critical peak temperature that a lamellar-like structure occurred in the alloy was found to be 1300 °C. These products were firstly characterized by transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) analysis, and they were essentially Ni matrix and carbides (MoC and chromium carbides) generated through local melting. The equivalent mechanical properties of the alloy relative to that of un-treated alloy were received owing to its unique architecture even the peak temperature during thermal cycle was up to 1350 °C. The results obtained suggests these lamellar-like products dispersed near the fusion line in a Ni–Mo–Cr welded joint will not influence the joint’s mechanical strength and stability while the peak temperature in the HAZ was adjusted below 1350 °C, providing valuable guideline in designing and applying the Ni–Mo–Cr system superalloys
Corneanu, Ciprian Adrian; Simon, Marc Oliu; Cohn, Jeffrey F; Guerrero, Sergio Escalera
2016-08-01
Facial expressions are an important way through which humans interact socially. Building a system capable of automatically recognizing facial expressions from images and video has been an intense field of study in recent years. Interpreting such expressions remains challenging and much research is needed about the way they relate to human affect. This paper presents a general overview of automatic RGB, 3D, thermal and multimodal facial expression analysis. We define a new taxonomy for the field, encompassing all steps from face detection to facial expression recognition, and describe and classify the state of the art methods accordingly. We also present the important datasets and the bench-marking of most influential methods. We conclude with a general discussion about trends, important questions and future lines of research. PMID:26761193
Turbulent energy dissipation and intermittency in ambipolar diffusion magnetohydrodynamics
Momferratos, Georgios; Falgarone, Edith; Forêts, Guillaume Pineau des
2015-01-01
The dissipation of kinetic and magnetic energy in the interstellar medium (ISM) can proceed through viscous, Ohmic or ambipolar diffusion (AD). It occurs at very small scales compared to the scales at which energy is presumed to be injected. This localized heating may impact the ISM evolution but also its chemistry, thus providing observable features. Here, we perform 3D spectral simulations of decaying magnetohydrodynamic turbulence including the effects of AD. We find that the AD heating power spectrum peaks at scales in the inertial range, due to a strong alignment of the magnetic and current vectors in the dissipative range. AD affects much greater scales than the AD scale predicted by dimensional analysis. We find that energy dissipation is highly concentrated on thin sheets. Its probability density function follows a lognormal law with a power-law tail which hints at intermittency, a property which we quantify by use of structure function exponents. Finally, we extract structures of high dissipation, de...
Rank of Stably Dissipative Graphs
Duarte, Pedro
2011-01-01
For the class of stably dissipative Lotka-Volterra systems we prove that the rank of its defining matrix, which is the dimension of the associated invariant foliation, is completely determined by the system's graph.
SIMULATION IN THERMAL DESIGN FOR ELECTRONIC CONTROL UNIT OF ELECTRONIC UNIT PUMP
Institute of Scientific and Technical Information of China (English)
XU Quankui; ZHU Keqing; ZHUO Bin; MAO Xiaojian; WANG Junxi
2008-01-01
The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit (ECU) design. By means of circuit simulation, the thermal design of ECU for electronic unit pump (EUP) fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time
Dissipative Effect and Tunneling Time
Directory of Open Access Journals (Sweden)
Samyadeb Bhattacharya
2011-01-01
Full Text Available The quantum Langevin equation has been studied for dissipative system using the approach of Ford et al. Here, we have considered the inverted harmonic oscillator potential and calculated the effect of dissipation on tunneling time, group delay, and the self-interference term. A critical value of the friction coefficient has been determined for which the self-interference term vanishes. This approach sheds new light on understanding the ion transport at nanoscale.
Institute of Scientific and Technical Information of China (English)
Wen LIU; Shuming XING; Peiwei BAO; Milan ZHANG; Liming XIAO
2007-01-01
The energy dissipation caused by the viscous force has great effects on the flow property of semi-solid metal during rheological processes such as slurry preparing, delivering and cavity filling. Experimental results in this paper indicate that the viscous friction between semi-solid metal and pipe wall, the collisions among the solid particles, and the liquid flow around particles are the three main types of energy dissipation. On the basis of the hydromechanics, the energy dissipation calculation model is built. It is demonstrated that the micro-structural parameters such as effective solid fraction, particle size and shape, and flow parameters such as the mean velocity, the fluctuant velocity of particles and the relative velocity between the fluid and solid phase, affect the energy dissipation of semi-solid metal.
International Nuclear Information System (INIS)
Graphical abstract: The present work demonstrates that the temperature dependence of the escape rate is not only embedded in the so-called Arrhenius type factor, the second exponential factor also includes the temperature dependence which has a purely quantum origin that is entangled with dissipation. Display Omitted Highlights: → We explore the noise-induced barrier crossing dynamics of an open quantum system. → The bath coupled with the system is driven out of equilibrium by an external noise. → Nonlinear system-bath coupling and modulation of the bath affect the escape rate. → An additional exponential factor, other than Arrhenius is also temperature dependent. → This temperature dependence is purely quantum in origin. - Abstract: We address the stochastic dynamics of an open quantum system coupled to a heat reservoir that is driven out of thermal equilibrium by an external noise. By constructing Langevin and Fokker-Planck equations, we obtain the rate of decay from a metastable state of the system when the dissipation is state dependent. We discuss the effects and consequences of the non-linear interaction(s) stemming out of the system-bath coupling alongside the modulation of the bath by an external noise on the rate expression. We demonstrate that the temperature dependence of the escape rate is not only embedded in the so-called Arrhenius type factor, the second exponential factor also includes the temperature dependence. The last effect has a purely quantum origin. Interestingly, we also envisage that this quantum effect is entangled with dissipation. The results offer a basis for clarifying the relationship between the dissipation and exponential factor of the obtained rate expression.
Energy Technology Data Exchange (ETDEWEB)
Shit, Anindita [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711 103 (India); Chattopadhyay, Sudip, E-mail: sudip_chattopadhyay@rediffmail.com [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711 103 (India); Ray Chaudhuri, Jyotipratim, E-mail: jprc_8@yahoo.com [Department of Physics, Katwa College, Katwa, Burdwan 713 130 (India)
2011-07-28
Graphical abstract: The present work demonstrates that the temperature dependence of the escape rate is not only embedded in the so-called Arrhenius type factor, the second exponential factor also includes the temperature dependence which has a purely quantum origin that is entangled with dissipation. Display Omitted Highlights: {yields} We explore the noise-induced barrier crossing dynamics of an open quantum system. {yields} The bath coupled with the system is driven out of equilibrium by an external noise. {yields} Nonlinear system-bath coupling and modulation of the bath affect the escape rate. {yields} An additional exponential factor, other than Arrhenius is also temperature dependent. {yields} This temperature dependence is purely quantum in origin. - Abstract: We address the stochastic dynamics of an open quantum system coupled to a heat reservoir that is driven out of thermal equilibrium by an external noise. By constructing Langevin and Fokker-Planck equations, we obtain the rate of decay from a metastable state of the system when the dissipation is state dependent. We discuss the effects and consequences of the non-linear interaction(s) stemming out of the system-bath coupling alongside the modulation of the bath by an external noise on the rate expression. We demonstrate that the temperature dependence of the escape rate is not only embedded in the so-called Arrhenius type factor, the second exponential factor also includes the temperature dependence. The last effect has a purely quantum origin. Interestingly, we also envisage that this quantum effect is entangled with dissipation. The results offer a basis for clarifying the relationship between the dissipation and exponential factor of the obtained rate expression.
Dissipation in small systems: Landau-Zener approach.
Barra, Felipe; Esposito, Massimiliano
2016-06-01
We establish a stochastic thermodynamics for a Fermionic level driven by a time-dependent force and interacting with initially thermalized levels playing the role of a reservoir. The driving induces consecutive avoided crossings between system and reservoir levels described within Landau-Zener theory. We derive the resulting system dynamics and thermodynamics and identify energy, work, heat, entropy, and dissipation. Our theory perfectly reproduces the numerically exact quantum work statistics obtained using a two point measurements approach of the total energy and provides an explicit expression for the dissipation in terms of diabatic transitions.
Entransy dissipation analysis and optimization of separated heat pipe system
Institute of Scientific and Technical Information of China (English)
QIAN XiaoDong; LI Zhen; MENG JiAn; LI ZhiXin
2012-01-01
Seperated heat pipe systems are widely used in the fields of waste heat recovery and air conditioning due to their high heat transfer capability,and optimization of heat transfer process plays an important role in high-efficiency energy utilization and energy conservation.In this paper,the entransy dissipation analysis is conducted for the separated heat pipe system,and the result indicates that minimum thermal resistance principle is applicable to the optimization of the separated heat pipe system.Whether in the applications of waste heat recovery or air conditioning,the smaller the entransy-dissipation-based thermal resistance of the separated heat pipe system is,the better the heat transfer performance will be.Based on the minimum thermal resistance principle,the optimal area allocation relationship between evaporator and condenser is deduced,which is numerically verified in the optimation design of separated heat pipe system.
Quantum Markov Chain Mixing and Dissipative Engineering
DEFF Research Database (Denmark)
Kastoryano, Michael James
2012-01-01
This thesis is the fruit of investigations on the extension of ideas of Markov chain mixing to the quantum setting, and its application to problems of dissipative engineering. A Markov chain describes a statistical process where the probability of future events depends only on the state of the sy....... Finally, we consider three independent tasks of dissipative engineering: dissipatively preparing a maximally entangled state of two atoms trapped in an optical cavity, dissipative preparation of graph states, and dissipative quantum computing construction....
Dilepton emission in high-energy heavy-ion collisions with dissipative hydrodynamics
Vujanovic, Gojko; Shen, Chun; Luzum, Matthew; Schenke, Bjoern; Jeon, Sangyoung; Gale, Charles
2015-01-01
In this contribution we study the effects of three transport coefficients of dissipative hydrodynamics on thermal dilepton anisotropic flow observables. The first two transport coefficients investigated influence the overall size and growth rate of shear viscous pressure, while the last transport coefficient governs the magnitude of net baryon number diffusion in relativistic dissipative fluid dynamics. All calculations are done using state-of-the-art 3+1D hydrodynamical simulations. We show that thermal dileptons are sensitive probes of the transport coefficients of dissipative hydrodynamics.
Work Fluctuation-Dissipation Trade-Off in Heat Engines.
Funo, Ken; Ueda, Masahito
2015-12-31
Reducing work fluctuation and dissipation in heat engines or, more generally, information heat engines that perform feedback control, is vital to maximize their efficiency. The same problem arises when we attempt to maximize the efficiency of a given thermodynamic task that undergoes nonequilibrium processes for arbitrary initial and final states. We find that the most general trade-off relation between work fluctuation and dissipation applicable to arbitrary nonequilibrium processes is bounded from below by the information distance characterizing how far the system is from thermal equilibrium. The minimum amount of dissipation is found to be given in terms of the relative entropy and the Renyi divergence, both of which quantify the information distance between the state of the system and the canonical distribution. We give an explicit protocol that achieves the fundamental lower bound of the trade-off relation.
The Bose-Hubbard model with squeezed dissipation
Quijandría, Fernando; Naether, Uta; Porras, Diego; José García-Ripoll, Juan; Zueco, David
2015-03-01
The stationary properties of the Bose-Hubbard model under squeezed dissipation are investigated. The dissipative model does not possess a U(1) symmetry but conserves parity. We find that =0 always holds, so no symmetry breaking occurs. Without the onsite repulsion, the linear case is known to be critical. At the critical point the system freezes to an EPR state with infinite two mode entanglement. We show here that the correlations are rapidly destroyed whenever the repulsion is switched on. As we increase the latter, the system approaches a thermal state with an effective temperature defined in terms of the squeezing parameter in the dissipators. We characterize this transition by means of a Gutzwiller ansatz and the Gaussian Hartree-Fock-Bogoliubov approximation.
DISSIPATIVE DIVERGENCE OF RESONANT ORBITS
Energy Technology Data Exchange (ETDEWEB)
Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Morbidelli, Alessandro, E-mail: kbatygin@gps.caltech.edu [Departement Cassiopee, Universite de Nice-Sophia Antipolis, Observatoire de la Cote d' Azur, F-06304 Nice (France)
2013-01-01
A considerable fraction of multi-planet systems discovered by the observational surveys of extrasolar planets reside in mild proximity to first-order mean-motion resonances. However, the relative remoteness of such systems from nominal resonant period ratios (e.g., 2:1, 3:2, and 4:3) has been interpreted as evidence for lack of resonant interactions. Here, we show that a slow divergence away from exact commensurability is a natural outcome of dissipative evolution and demonstrate that libration of critical angles can be maintained tens of percent away from nominal resonance. We construct an analytical theory for the long-term dynamical evolution of dissipated resonant planetary pairs and confirm our calculations numerically. Collectively, our results suggest that a significant fraction of the near-commensurate extrasolar planets are in fact resonant and have undergone significant dissipative evolution.
Energy dissipation in circular tube
Directory of Open Access Journals (Sweden)
A.D. Girgidov
2012-01-01
Full Text Available Energy dissipation distribution along the circular tube radius is important in solving such problems as calculation of heat transfer by the air flow through building envelope; calculation of pressure loss in spiral flows; calculation of cyclones with axial and tangential supply of dust-containing gas.Two types of one-dimensional radially axisymmetric flows in circular tube were considered: axial flow and rotation about the axis (Rankine vortex. Relying on two- and four-layer description of axial turbulent flow energy dissipation was calculated in each layer.Similar calculation for Rankine vortex with viscous sublayer at the tube surface was provided. By employing the dissipation minimum principle the boundary radius between rigid rotation and free vortex is calculated. Approximation of the velocity distribution in Rankine vortex is proposed.
Dissipative structures and related methods
Langhorst, Benjamin R; Chu, Henry S
2013-11-05
Dissipative structures include at least one panel and a cell structure disposed adjacent to the at least one panel having interconnected cells. A deformable material, which may comprise at least one hydrogel, is disposed within at least one interconnected cell proximate to the at least one panel. Dissipative structures may also include a cell structure having interconnected cells formed by wall elements. The wall elements may include a mesh formed by overlapping fibers having apertures formed therebetween. The apertures may form passageways between the interconnected cells. Methods of dissipating a force include disposing at least one hydrogel in a cell structure proximate to at least one panel, applying a force to the at least one panel, and forcing at least a portion of the at least one hydrogel through apertures formed in the cell structure.
Introduction to thermal transport
Phillpot, Simon R.; Alan J. H. McGaughey
2005-01-01
The relentless increase in the thermal loads imposed on devices and materials structures is driving renewed interest among materials scientists and engineers in the area of thermal transport. Applications include thermal barrier coatings on turbine blades, thermoelectric coolers, high-performance thermal transfer liquids, and heat dissipation in microelectronics. These, and other applications, demand not only ever more efficient thermal management, but also a better fundamental understanding ...
Himeda, M; Njintang, Y N; Gaiani, C; Nguimbou, R M; Scher, J; Facho, B; Mbofung, C M F
2014-09-01
The study was aimed at determining the effect of harvesting time and drying method on the thermal and physicochemical properties of taro powder, Sosso ecotype. A 5 × 2 factorial experiment with 5 harvesting times (6, 7, 8, 9 and 10 months after planting) and 2 drying methods (sun and electric oven drying) was used for this purpose. The variance component analysis revealed harvesting time as the most important factor affecting all the variables measured. In particular the proteins and available sugar contents of the powders increased significantly with increase in harvesting time. The same was true of the gelling property and water absorption capacity of the powders. It was equally observed that the temperatures (start, peak and end) and enthalpy of gelatinization of the powders increased with harvesting time. It is concluded that harvesting sosso-taro at full maturity (10 months after planting) and sun-drying produces food powders with excellent gelling properties among others.
Himeda, M; Njintang, Y N; Gaiani, C; Nguimbou, R M; Scher, J; Facho, B; Mbofung, C M F
2014-09-01
The study was aimed at determining the effect of harvesting time and drying method on the thermal and physicochemical properties of taro powder, Sosso ecotype. A 5 × 2 factorial experiment with 5 harvesting times (6, 7, 8, 9 and 10 months after planting) and 2 drying methods (sun and electric oven drying) was used for this purpose. The variance component analysis revealed harvesting time as the most important factor affecting all the variables measured. In particular the proteins and available sugar contents of the powders increased significantly with increase in harvesting time. The same was true of the gelling property and water absorption capacity of the powders. It was equally observed that the temperatures (start, peak and end) and enthalpy of gelatinization of the powders increased with harvesting time. It is concluded that harvesting sosso-taro at full maturity (10 months after planting) and sun-drying produces food powders with excellent gelling properties among others. PMID:25190840
Dissipation in Relativistic Outflows: A Multisource Overview
Thompson, Christopher
2013-01-01
Relativistically expanding sources of X-rays and gamma-rays cover an enormous range of (central) compactness and Lorentz factor. The underlying physics is discussed, with an emphasis on how the dominant dissipative mode and the emergent spectrum depend on these parameters. Photons advected outward from high optical depth are a potentially important source of Compton seeds. Their characteristic energy is bounded below by ~1 MeV in pair-loaded outflows of relatively low compactness, and remains near ~1 MeV at very high compactness and low matter loading. This is compared with the characteristic energy of O(1) MeV observed in the rest frame spectra of many sources, including gamma-ray bursts, OSSE jet sources, MeV Blazars, and the intense initial 0.1 s pulse of the March 5 event. Additional topics discussed include the feedback of pair creation on electron heating and the formation of non-thermal spectra, their effectiveness at shielding the dissipative zone from ambient photons, direct Compton damping of irregu...
Dissipative heavy-ion collisions
International Nuclear Information System (INIS)
This report is a compilation of lecture notes of a series of lectures held at Argonne National Laboratory in October and November 1984. The lectures are a discussion of dissipative phenomena as observed in collisions of atomic nuclei. The model is based on a system which has initially zero temperature and the initial energy is kinetic and binding energy. Collisions excite the nuclei, and outgoing fragments or the compound system deexcite before they are detected. Brownian motion is used to introduce the concept of dissipation. The master equation and the Fokker-Planck equation are derived. 73 refs., 59 figs
ENERGY DISSIPATION PROCESSES IN SOLAR WIND TURBULENCE
Energy Technology Data Exchange (ETDEWEB)
Wang, Y.; Wei, F. S.; Feng, X. S.; Sun, T. R.; Zuo, P. B. [SIGMA Weather Group, State Key Laboratory for Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); Xu, X. J. [Space Science Institute, Macau University of Science and Technology, Macao (China); Zhang, J., E-mail: yw@spaceweather.ac.cn [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, MSN 3F3, Fairfax, Virginia 22030 (United States)
2015-12-15
Turbulence is a chaotic flow regime filled by irregular flows. The dissipation of turbulence is a fundamental problem in the realm of physics. Theoretically, dissipation ultimately cannot be achieved without collisions, and so how turbulent kinetic energy is dissipated in the nearly collisionless solar wind is a challenging problem. Wave particle interactions and magnetic reconnection (MR) are two possible dissipation mechanisms, but which mechanism dominates is still a controversial topic. Here we analyze the dissipation region scaling around a solar wind MR region. We find that the MR region shows unique multifractal scaling in the dissipation range, while the ambient solar wind turbulence reveals a monofractal dissipation process for most of the time. These results provide the first observational evidences for intermittent multifractal dissipation region scaling around a MR site, and they also have significant implications for the fundamental energy dissipation process.
Effective field theory of dissipative fluids
Crossley, Michael; Liu, Hong
2015-01-01
We develop an effective field theory for dissipative fluids which governs the dynamics of gapless modes associated to conserved quantities. The system is put in a curved spacetime and coupled to external sources for charged currents. The invariance of the hydrodynamical action under gauge symmetries and diffeomorphisms suggests a natural set of dynamical variables which provide a mapping between an emergent "fluid spacetime" and the physical spacetime. An essential aspect of our formulation is to identify the appropriate symmetries in the fluid spacetime. Our theory applies to nonlinear disturbances around a general density matrix. For a thermal density matrix, we require an additional Z_2 symmetry, to which we refer as the local KMS condition. This leads to the standard constraints of hydrodynamics, as well as a nonlinear generalization of the Onsager relations. It also leads to an emergent supersymmetry in the classical statistical regime, with a higher derivative version required for the full quantum regim...
Fluctuation and dissipation in de Sitter space
Fischler, Willy; Pedraza, Juan F; Tangarife, Walter
2014-01-01
In this paper we study some thermal properties of quantum field theories in de Sitter space by means of holographic techniques. We focus on the static patch of de Sitter and assume that the quantum fields are in the standard Bunch-Davies vacuum. More specifically, we follow the stochastic motion of a massive charged particle due to its interaction with Hawking radiation. The process is described in terms of the theory of Brownian motion in inhomogeneous media and its associated Langevin dynamics. At late times, we find that the particle undergoes a regime of slow diffusion and never reaches the horizon, in stark contrast to the usual random walk behavior at finite temperature. Nevertheless, the fluctuation-dissipation theorem is found to hold at all times.
Harvesting dissipated energy with a mesoscopic ratchet.
Roche, B; Roulleau, P; Jullien, T; Jompol, Y; Farrer, I; Ritchie, D A; Glattli, D C
2015-04-01
The search for new efficient thermoelectric devices converting waste heat into electrical energy is of major importance. The physics of mesoscopic electronic transport offers the possibility to develop a new generation of nanoengines with high efficiency. Here we describe an all-electrical heat engine harvesting and converting dissipated power into an electrical current. Two capacitively coupled mesoscopic conductors realized in a two-dimensional conductor form the hot source and the cold converter of our device. In the former, controlled Joule heating generated by a voltage-biased quantum point contact results in thermal voltage fluctuations. By capacitive coupling the latter creates electric potential fluctuations in a cold chaotic cavity connected to external leads by two quantum point contacts. For unequal quantum point contact transmissions, a net electrical current is observed proportional to the heat produced.
Scaling laws for the upper ocean temperature dissipation rate
Bogucki, D.J.; Huguenard, K.; Haus, B.K.; Özgökmen, T.M.; Reniers, A.J.H.M.; Laxague, N.J.M.
2015-01-01
Our understanding of temperature dissipation rate χ within the upper ocean boundary layer, which is critical for climate forecasts, is very limited. Near-surface turbulence also affects dispersion of contaminants and biogeochemical tracers. Using high-resolution optical turbulence measurements, scal
Turbulent Dissipation Challenge -- Problem Description
Parashar, Tulasi N; Wicks, Robert; Karimabadi, Homa; Chandran, S Peter Gary Benjamin; Matthaeus, William H
2014-01-01
The goal of this document is to present a detailed description of the goals, simulation setup and diagnostics for the Turbulent Dissipation Challenge $($http://arxiv.org/abs/1303.0204$)$ as discussed in the Solar Heliospheric and INterplanetary Environment $($SHINE$)$ 2013 workshop, American Geophysical Union Fall Meeting 2013 and the accompanying antenna meeting in Berkeley.
Impacts on Dissipative Sonic Vacuum
Xu, Yichao; Nesterenko, Vitali
We investigate the propagating compression bell shape stress waves generated by the strikers with different masses impacting the sonic vacuum - the discrete dissipative strongly nonlinear metamaterial with zero long wave sound speed. The metamaterial is composed of alternating steel disks and Nitrile O-rings. Being a solid material, it has exceptionally low speed of the investigated stress waves in the range of 50 - 74 m/s, which is a few times smaller than the speed of sound or shock waves in air generated by blast. The shape of propagating stress waves was dramatically changed by the viscous dissipation. It prevented the incoming pulses from splitting into trains of solitary waves, a phenomenon characteristic of the non-dissipative strongly nonlinear discrete systems when the striker mass is larger than the cell mass. Both high-speed camera images and numerical simulations demonstrate the unusual rattling behavior of the top disk between the striker and the rest of the system. The linear momentum and energy from the striker were completely transferred to the metamaterial. This strongly nonlinear dissipative metamaterial can be designed for the optimal attenuation of dynamic loads generated by impact or contact explosion. Author 1 wants to acknowledge the support provided by UCSD.
Dissipation of chlorpyrifos on pakchoi inside and outside greenhouse
Institute of Scientific and Technical Information of China (English)
YU Yun-long; FANG Hua; WANG Xiao; YU Jing-quan; FAN De-fang
2005-01-01
The dissipation of chlorpyrifos on pakchoi inside and outside greenhouse was studied. The decline curve of chlorpyrifos on pakchoi could be described as first-order kinetic. The experimental data showed that both the hermetic environment of greenhouse and season affected dissipation rates of chlorpyrifos on pakchoi. Chlorpyrifos declined faster outside greenhouse than inside greenhouse.Chlorpyrifos residues at pre-harvest time were below the maximum residue limits (MRLs) fixed in China, whereas the values inside greenhouse were higher than those outside greenhouse by almost 50%. The recommended pre-harvest time established under conditions of open field might not always fit to greenhouse production.
An essential mechanism of heat dissipation in carbon nanotube electronics.
Rotkin, Slava V; Perebeinos, Vasili; Petrov, Alexey G; Avouris, Phaedon
2009-05-01
Excess heat generated in integrated circuits is one of the major problems of modern electronics. Surface phonon-polariton scattering is shown here to be the dominant mechanism for hot charge carrier energy dissipation in a nanotube device fabricated on a polar substrate, such as SiO(2). By use of microscopic quantum models, the Joule losses were calculated for the various energy dissipation channels as a function of the electric field, doping, and temperature. The polariton mechanism must be taken into account to obtain an accurate estimate of the effective thermal coupling of the nonsuspended nanotube to the substrate, which was found to be 0.1-0.2 W/(m x K) even in the absence of the bare phononic thermal coupling. PMID:19334687
García-Gil, Alejandro; Vázquez-Suñe, Enric; Schneider, Eduardo Garrido; Sánchez-Navarro, José Ángel; Mateo-Lázaro, Jesús
2014-07-01
The extensive implementation of ground source heat pumps in urban aquifers is an important issue related to groundwater quality and the future economic feasibility of existent geothermal installations. Although many cities are in the immediate vicinity of large rivers, little is known about the thermal river-groundwater interaction at a kilometric-scale. The aim of this work is to evaluate the thermal impact of river water recharges induced by flood events into an urban alluvial aquifer anthropogenically influenced by geothermal exploitations. The present thermal state of an urban aquifer at a regional scale, including 27 groundwater heat pump installations, has been evaluated. The thermal impacts of these installations in the aquifer together with the thermal impacts from "cold" winter floods have also been spatially and temporally evaluated to ensure better geothermal management of the aquifer. The results showed a variable direct thermal impact from 0 to 6 °C depending on the groundwater-surface water interaction along the river trajectory. The thermal plumes far away from the riverbed also present minor indirect thermal impacts due to hydraulic gradient variations.
Energy dissipation processes in solar wind turbulence
Wang, Y; Feng, X S; Xu, X J; Zhang, J; Sun, T R; Zuo, P B
2015-01-01
Turbulence is a chaotic flow regime filled by irregular flows. The dissipation of turbulence is a fundamental problem in the realm of physics. Theoretically, dissipation cannot be ultimately achieved without collisions, and so how turbulent kinetic energy is dissipated in the nearly collisionless solar wind is a challenging problem. Wave particle interactions and magnetic reconnection are two possible dissipation mechanisms, but which mechanism dominates is still a controversial topic. Here we analyze the dissipation region scaling around a solar wind magnetic reconnection region. We find that the magnetic reconnection region shows a unique multifractal scaling in the dissipation range, while the ambient solar wind turbulence reveals a monofractal dissipation process for most of the time. These results provide the first observational evidences for the intermittent multifractal dissipation region scaling around a magnetic reconnection site, and they also have significant implications for the fundamental energy...
Persistent Currents and Dissipation in Narrow Bilayer Quantum Hall Bars
Kyriakidis, Jordan; Radzihovsky, Leo
2000-01-01
Bilayer quantum Hall states support a flow of nearly dissipationless staggered current which can only decay through collective channels. We study the dominant finite-temperature dissipation mechanism which in narrow bars is driven by thermal nucleation of pseudospin solitons. We find the finite-temperature resistivity, predict the resulting staggered current-voltage characteristics, and calculate the associated zero-temperature critical staggered current and gate voltage.
Classical and quantum dissipation in non homogeneous environments
Illuminati, F.; Patriarca, M.; Sodano, P.
1994-01-01
We generalize the oscillator model of a particle interacting with a thermal reservoir by introducing arbitrary nonlinear couplings in the particle coordinates.The equilibrium positions of the heat bath oscillators are promoted to space-time functions, which are shown to represent a modulation of the internal noise by the external forces. The model thus provides a description of classical and quantum dissipation in non homogeneous environments. In the classical case we derive a generalized Lan...
Deformed quantum harmonic oscillator with diffusion and dissipation
ISAR, A.; Scheid, W.
2007-01-01
A master equation for the deformed quantum harmonic oscillator interacting with a dissipative environment, in particular with a thermal bath, is derived in the microscopic model by using perturbation theory. The coefficients of the master equation and of equations of motion for observables depend on the deformation function. The steady state solution of the equation for the density matrix in the number representation is obtained and the equilibrium energy of the deformed harmonic oscillator i...
Directory of Open Access Journals (Sweden)
K.V. Prasad
2013-01-01
Full Text Available The present study investigates the effects of internal heat generation/absorption, thermal radiation, magnetic field, and temperature-dependent thermal conductivity on the flow and heat transfer characteristics of a Non-Newtonian Maxwell fluid over a stretching sheet. The upper convected Maxwell fluid model is used to characterize the non-Newtonian fluid behavior. Similarity solutions for the governing equations are obtained with prescribed surface temperature (PST and/or with prescribed surface heat flux (PHF. Numerical solutions for the governing equations subject to the appropriate boundary conditions are obtained by a finite difference scheme known as Keller-Box method. The numerical results thus obtained are analyzed for the effects of the several pertinent parameters namely, the Maxwell parameter, the magnetic parameter, the temperature-dependent thermal conductivity parameter, the heat source/sink parameter, the Prandtl number, the Eckert number, and the thermal radiation parameter on the flow and heat transfer fields. Results for the velocity and temperature fields, skin friction, and Nusselt number are shown through graphs. It is observed that the thermal boundary layer thickness increases with increasing values of the elasticity parameter and the magnetic parameter; however it decreases with the Prandtl number.
Tides on the Moon: Theory and determination of dissipation
Williams, James G.; Boggs, Dale. H.
2015-04-01
Solid body tides on the Moon vary by about ±0.1 m each month. In addition to changes in shape, the Moon's gravity field and orientation in space are affected by tides. The tidal expressions for an elastic sphere are compact, but dissipation introduces modifications that depend on the forcing period. Consequently, a Fourier representation of the tide-raising potential is needed. A mathematical model for the distortion-caused tidal potential may be used for the analysis of precise spacecraft tracking data. Since tides affect gravitational torques on the Moon from the Earth's attraction, the lunar orientation is also affected. Expressions for five periodic perturbations of orientation are presented. The rheological properties of lunar materials determine how the Moon responds to different tidal periods. New lunar laser ranging solutions for the tidal orientation terms are presented. The quality factor Q is 38 ± 4 at 1 month, 41 ± 9 at 1 year, ≥74 at 3 years, and ≥58 at 6 years. The ranging results can be matched with absorption band models that peak at ~120 days and single relaxation time models that peak at ~100 days. Combined models are possibilities. Dissipation can modify laser ranging solutions; previously reported core flattening is too uncertain to be useful. Strong lunar tidal dissipation, modeled to arise in the deep hot mantle, appears to be from a region with radius ≥535 km. Classical Maxwell-type dissipation is too weak to detect at 3 and 6 year periods.
Dynamo action in dissipative, forced, rotating MHD turbulence
Shebalin, John V.
2016-06-01
Magnetohydrodynamic (MHD) turbulence is an inherent feature of large-scale, energetic astrophysical and geophysical magnetofluids. In general, these are rotating and are energized through buoyancy and shear, while viscosity and resistivity provide a means of dissipation of kinetic and magnetic energy. Studies of unforced, rotating, ideal (i.e., non-dissipative) MHD turbulence have produced interesting results, but it is important to determine how these results are affected by dissipation and forcing. Here, we extend our previous work and examine dissipative, forced, and rotating MHD turbulence. Incompressibility is assumed, and finite Fourier series represent turbulent velocity and magnetic field on a 643 grid. Forcing occurs at an intermediate wave number by a method that keeps total energy relatively constant and allows for injection of kinetic and magnetic helicity. We find that 3-D energy spectra are asymmetric when forcing is present. We also find that dynamo action occurs when forcing has either kinetic or magnetic helicity, with magnetic helicity injection being more important. In forced, dissipative MHD turbulence, the dynamo manifests itself as a large-scale coherent structure that is similar to that seen in the ideal case. These results imply that MHD turbulence, per se, may play a fundamental role in the creation and maintenance of large-scale (i.e., dipolar) stellar and planetary magnetic fields.
Compaction shock dissipation in low density granular explosive
Rao, Pratap T.; Gonthier, Keith A.; Chakravarthy, Sunada
2016-06-01
The microstructure of granular explosives can affect dissipative heating within compaction shocks that can trigger combustion and initiate detonation. Because initiation occurs over distances that are much larger than the mean particle size, homogenized (macroscale) theories are often used to describe local thermodynamic states within and behind shocks that are regarded as the average manifestation of thermodynamic fields at the particle scale. In this paper, mesoscale modeling and simulation are used to examine how the initial packing density of granular HMX (C4H8N8O8) C4H8N8O8 having a narrow particle size distribution influences dissipation within resolved, planar compaction shocks. The model tracks the evolution of thermomechanical fields within large ensembles of particles due to pore collapse. Effective shock profiles, obtained by averaging mesoscale fields over space and time, are compared with those given by an independent macroscale compaction theory that predicts the variation in effective thermomechanical fields within shocks due to an imbalance between the solid pressure and a configurational stress. Reducing packing density is shown to reduce the dissipation rate within shocks but increase the integrated dissipated work over shock rise times, which is indicative of enhanced sensitivity. In all cases, dissipated work is related to shock pressure by a density-dependent power law, and shock rise time is related to pressure by a power law having an exponent of negative one.
Amphetamine enhances endurance by increasing heat dissipation.
Morozova, Ekaterina; Yoo, Yeonjoo; Behrouzvaziri, Abolhassan; Zaretskaia, Maria; Rusyniak, Daniel; Zaretsky, Dmitry; Molkov, Yaroslav
2016-09-01
Athletes use amphetamines to improve their performance through largely unknown mechanisms. Considering that body temperature is one of the major determinants of exhaustion during exercise, we investigated the influence of amphetamine on the thermoregulation. To explore this, we measured core body temperature and oxygen consumption of control and amphetamine-trea ted rats running on a treadmill with an incrementally increasing load (both speed and incline). Experimental results showed that rats treated with amphetamine (2 mg/kg) were able to run significantly longer than control rats. Due to a progressively increasing workload, which was matched by oxygen consumption, the control group exhibited a steady increase in the body temperature. The administration of amphetamine slowed down the temperature rise (thus decreasing core body temperature) in the beginning of the run without affecting oxygen consumption. In contrast, a lower dose of amphetamine (1 mg/kg) had no effect on measured parameters. Using a mathematical model describing temperature dynamics in two compartments (the core and the muscles), we were able to infer what physiological parameters were affected by amphetamine. Modeling revealed that amphetamine administration increases heat dissipation in the core. Furthermore, the model predicted that the muscle temperature at the end of the run in the amphetamine-treated group was significantly higher than in the control group. Therefore, we conclude that amphetamine may mask or delay fatigue by slowing down exercise-induced core body temperature growth by increasing heat dissipation. However, this affects the integrity of thermoregulatory system and may result in potentially dangerous overheating of the muscles.
Scaling laws to quantify tidal dissipation in star-planet systems
Auclair-Desrotour, Pierre; Poncin-Lafitte, Christophe Le
2015-01-01
Planetary systems evolve over secular time scales. One of the key mechanisms that drive this evolution is tidal dissipation. Submitted to tides, stellar and planetary fluid layers do not behave like rocky ones. Indeed, they are the place of resonant gravito-inertial waves. Therefore, tidal dissipation in fluid bodies strongly depends on the excitation frequency while this dependence is smooth in solid ones. Thus, the impact of the internal structure of celestial bodies must be taken into account when studying tidal dynamics. The purpose of this work is to present a local model of tidal gravito-inertial waves allowing us to quantify analytically the internal dissipation due to viscous friction and thermal diffusion, and to study the properties of the resonant frequency spectrum of the dissipated energy. We derive from this model scaling laws characterizing tidal dissipation as a function of fluid parameters (rotation, stratification, diffusivities) and discuss them in the context of star-planet systems.
Modeling helicity dissipation-rate equation
Yokoi, Nobumitsu
2016-01-01
Transport equation of the dissipation rate of turbulent helicity is derived with the aid of a statistical analytical closure theory of inhomogeneous turbulence. It is shown that an assumption on the helicity scaling with an algebraic relationship between the helicity and its dissipation rate leads to the transport equation of the turbulent helicity dissipation rate without resorting to a heuristic modeling.
Integral Dissipative Set-valued Maps
Directory of Open Access Journals (Sweden)
M. O. Ogundiran
2008-01-01
Full Text Available Integral dissipativity arises over a period of time. This dissipativity for multivalued maps has some intrinsic properties together with their convexification. The space of Aumann integrable maps endowed with Hausdorff topology having this dissipativity condition is a complete metric space.
From Molecular Dynamics to Dissipative Particle Dynamics
Flekkoy, Eirik G.; Coveney, Peter V.
1999-01-01
A procedure is introduced for deriving a coarse-grained dissipative particle dynamics from molecular dynamics. The rules of the dissipative particle dynamics are derived from the underlying molecular interactions, and a Langevin equation is obtained that describes the forces experienced by the dissipative particles and specifies the associated canonical Gibbs distribution for the system.
Directory of Open Access Journals (Sweden)
Sabine eVögeli
2015-05-01
Full Text Available Many stimuli evoke short-term emotional reactions. These reactions may play an important role in assessing how a subject perceives a stimulus. Additionally, long-term mood may modulate the emotional reactions but it is still unclear in what way. The question seems to be important in terms of animal welfare, as a negative mood may taint emotional reactions. In the present study with sheep, we investigated the effects of thermal stimuli on emotional reactions and the potential modulating effect of mood induced by manipulations of the housing conditions. We assume that unpredictable, stimulus-poor conditions lead to a negative and predictable, stimulus-rich conditions to a positive mood state. The thermal stimuli were applied to the upper breast during warm ambient temperatures: hot (as presumably negative, intermediate, and cold (as presumably positive. We recorded cortical activity by functional near-infrared spectroscopy, restlessness behavior (e.g. locomotor activity, aversive behaviors and ear postures as indicators of emotional reactions. The strongest hemodynamic reaction was found during a stimulus of intermediate valence independent of the animal’s housing conditions, whereas locomotor activity, ear movements and aversive behaviors were seen most in sheep from the unpredictable, stimulus-poor housing conditions, independent of stimulus valence. We conclude that, sheep perceived the thermal stimuli and differentiated between some of them. An adequate interpretation of the neuronal activity pattern remains difficult, though. The effects of housing conditions were small indicating that the induction of mood was only modestly efficacious. Therefore, a modulating effect of mood on the emotional reaction was not found.
Directory of Open Access Journals (Sweden)
Burcu Gülsevil Belber
2015-09-01
Full Text Available In this study, it was mentioned the situation of thermal tourism in Turkey and in the world, Turkey’s geothermal potential and utilization of the thermal tourism, the characteristics of the thermal waters and benefits in terms of health, activities related to the subject of the tourism ministry, elements of the marketing mix in the thermal plant, the status of the thermalplant in Kırşehir, a research about determining the level of satisfaction of the consumer who staying in thermal plants. Research was conducted by applying the survey methods to the tourist consumer accommodate in thermal plants. It has been demonstrated the factors affecting the level of satisfaction of participants by the agency of factor analysis and MANOVA analysis were made for the purpose ofresearch and were determined whether if they show changes according to demographic characteristics. According to results, it has appeared as the impact of factors “process management”, qualifications of the facility employees”, “qualifications of the facility”, “repurchase and recommend behaviors” on satisfaction of the consumer and these factors vary according totheir demographic characteristics.
Dissipation by a crystallization process
Dorosz, Sven; Voigtmann, Thomas; Schilling, Tanja
2016-01-01
We discuss crystallization as a non-equilibrium process. In a system of hard spheres under compression at a constant rate, we quantify the amount of heat that is dissipated during the crystallization process. We interpret the dissipation as arising from the resistance of the system against phase transformation. An intrinsic compression rate is identified that separates a quasi-static regime from one of rapidly driven crystallization. In the latter regime the system crystallizes more easily, because new relaxation channels are opened, at the cost of forming a higher fraction of non-equilibrium crystal structures. We rationalize the change in the crystallization mechanism by analogy with shear thinning, in terms of a kinetic competition between near-equilibrium relaxation and external driving.
Dissipation and nuclear collective motion
International Nuclear Information System (INIS)
This contribution is intended to give a brief summary of a forthcoming paper which shall review extensively the linear response theory for dissipation and statistical fluctuations as well as its application to heavy-ion collisions. It shall contain new results on the following subjects: numerical computations of response functions and transport coefficients; dissipation in a self-consistent treatment of harmonic vibrations; introduction of collective variables within a quantum theory. The method used consists of an extended version of the Bohm and Pines treatment of the electron gas. It allows to deduce a quantum Hamiltonian for the collective and intrinsic motion including coupling terms; discussion and solution of a quantal Master equation for non-linear collective motion. Additionally, a somewhat elaborate discussion of the problems of irreversibility is given, especially in connection to a treatment within the moving basis
Quantum bouncer with quadratic dissipation
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, G. [NanoScience Technology Center, University of Central Florida, Orlando, FL 32826 (United States)]. e-mail: ggonzalez@physics.ucf.edu
2008-07-01
The energy loss due to a quadratic velocity-dependent force on a quantum particle bouncing off a perfectly reflecting surface is obtained for a full cycle of motion. We approach this problem by means of a new, effective, phenomenological Hamiltonian which corresponds to the actual energy of the system and obtain the correction to the eigenvalues of the energy in first-order quantum perturbation theory for the case of weak dissipation. (Author)
Quantum bouncer with quadratic dissipation
González, G.
2008-02-01
The energy loss due to a quadratic velocity dependent force on a quantum particle bouncing on a perfectly reflecting surface is obtained for a full cycle of motion. We approach this problem by means of a new effective phenomenological Hamiltonian which corresponds to the actual energy of the system and obtained the correction to the eigenvalues of the energy in first order quantum perturbation theory for the case of weak dissipation.
Dissipative dynamics in particle physics
Romano, R
2003-01-01
The subject of this thesis is the study of dissipative dynamics and their properties in particle physics, dealing with neutral B-mesons, neutron interferometry and neutrino physics. Modified expressions for the relevant phenomenological quantities characterizing these systems are obtained. Moreover, the models presented in this work offer the possibility of direct tests of some basic properties of reduced dynamics (in particular the notion of complete positivity) since they represent concrete systems amenable to actual experiments.
TIDALLY INDUCED THERMAL RUNAWAYS ON EXTRASOLAR EARTHS: IMPACT ON HABITABILITY
International Nuclear Information System (INIS)
We study the susceptibility of extrasolar Earth-like planets to tidal dissipation by varying orbital, rheological, and heat transfer parameters. We employ a three-dimensional numerical method solving the coupled problem of mantle convection and tidal dissipation. A reference model mimicking a plate tectonic regime and reproducing Earth's present-day heat output is considered. Four other models representing less efficient heat transfer regimes are also investigated. For these five initial models, we determine the orbital configurations under which a positive feedback between tidal dissipation and temperature evolution leads to a thermal runaway. In order to describe the occurrence of thermal runaways, we develop a scaling that relates the global dissipated power to a characteristic temperature and to the orbital parameters. For all numerical experiments sharing the same initial temperature conditions, we show that the reciprocal value of the runaway timescale depends linearly on the global dissipated power at the beginning of the simulation. In the plate tectonic-like regime, Earth-like planets in the habitable zone (HZ) of 0.1 Msun stars experience thermal runaways for 1:1 spin-orbit resonance if the eccentricity is sufficiently high (e>0.02 at a 4 day period, e>0.2 at a 10 day period). For less efficient convective regimes, runaways are obtained for eccentricities as low as ∼0.004 at the inner limit of the HZ. In the case of 3:2 spin-orbit resonance, the occurrence of thermal runaways is independent of eccentricity and is predicted for orbital periods lower than 12 days. For less efficient convective regimes, runaways may occur at larger orbital periods potentially affecting the HZ of stars with a mass up to 0.4 Msun. Whatever the convective regime and spin-orbit resonance, tidal heating within Earth-like planets orbiting in the HZ of stars more massive than 0.5 Msun is not significant.
International Nuclear Information System (INIS)
The work presents the development of new algorithms for calculating the fraction of thermal energy dissipated during the irradiation on the inner surface of pores. On the basis of these algorithms, the simulation of heat transfer in three-layered systems was carried out taking into account the dissipation of thermal energy in specimens having different porosity. We have performed quantitative estimates of the portion of dissipating thermal energy and its influence on the distribution of thermal stresses in thermal barrier coating systems. It was demonstrated that the presence of pores with a large internal surface area in the intermediate layer material enables two-fold decrease of the internal thermal stresses
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
In the viewpoint of heat transfer, heat transport potential capacity and its dissipation are defined based on the essence of heat transport phenomenon. Respectively, their physical meanings are the overall heat transfer capabilityand the dissipation rate of the heat transfer capacity. Then the least dissipation principle of heat transport potential capacity is presented to enhance the heat conduction efficiency in the heat conduction optimization. The principle is,for a conduction process with the constant integral of the thermal conductivityover the region, the optimal distribution of thermal conductivity, which corresponds to the highest heat conduction efficiency, is characterized by the least dissipation of heat transport potential capacity. Finally the principle is applied to some cases in heat conduction optimization.
Effect of heat treatment on mechanical dissipation in Ta$_2$O$_5$ coatings
Martin, I W; Nawrodt, R; Fejer, M M; Gretarsson, A; Gustafson, E; Harry, G; Hough, J; MacLaren, I; Penn, S; Reid, S; Route, R; Rowan, S; Schwar, C; Seidel, P; Scott, J; Woodcraft, A L
2010-01-01
Thermal noise arising from mechanical dissipation in dielectric reflective coatings is expected to critically limit the sensitivity of precision measurement systems such as high-resolution optical spectroscopy, optical frequency standards and future generations of interferometric gravitational wave detectors. We present measurements of the effect of post-deposition heat treatment on the temperature dependence of the mechanical dissipation in ion-beam sputtered tantalum pentoxide between 11\\,K and 300\\,K. We find the temperature dependence of the dissipation is strongly dependent on the temperature at which the heat treatment was carried out, and we have identified three dissipation peaks occurring at different heat treatment temperatures. At temperatures below 200\\,K, the magnitude of the loss was found to increase with higher heat treatment temperatures, indicating that heat treatment is a significant factor in determining the level of coating thermal noise.
Transient chaotic transport in dissipative drift motion
Oyarzabal, R. S.; Szezech, J. D.; Batista, A. M.; de Souza, S. L. T.; Caldas, I. L.; Viana, R. L.; Sanjuán, M. A. F.
2016-04-01
We investigate chaotic particle transport in magnetised plasmas with two electrostatic drift waves. Considering dissipation in the drift motion, we verify that the removed KAM surfaces originate periodic attractors with their corresponding basins of attraction. We show that the properties of the basins depend on the dissipation and the space-averaged escape time decays exponentially when the dissipation increases. We find positive finite time Lyapunov exponents in dissipative drift motion, consequently the trajectories exhibit transient chaotic transport. These features indicate how the transient plasma transport depends on the dissipation.
Landau-Zener transitions mediated by an environment: Population transfer and energy dissipation
International Nuclear Information System (INIS)
We study Landau-Zener transitions between two states with the addition of a shared discretized continuum. The continuum allows for population decay from the initial state as well as indirect transitions between the two states. The probability of nonadiabatic transition in this multichannel model preserves the standard Landau-Zener functional form except for a shift in the usual exponential factor, reflecting population transfer into the continuum. We provide an intuitive explanation for this behavior assuming individual, independent transitions between pairs of states. In contrast, the ground state survival probability at long time shows a novel, non-monotonic, functional form with an oscillatory behavior in the sweep rate at low sweep rate values. We contrast the behavior of this open-multistate model to other generalized Landau-Zener models incorporating an environment: the stochastic Landau-Zener model and the dissipative case, where energy dissipation and thermal excitations affect the adiabatic region. Finally, we present evidence that the continuum of states may act to shield the two-state Landau-Zener transition probability from the effect of noise
Advanced thermal management materials
Jiang, Guosheng; Kuang, Ken
2012-01-01
""Advanced Thermal Management Materials"" provides a comprehensive and hands-on treatise on the importance of thermal packaging in high performance systems. These systems, ranging from active electronically-scanned radar arrays to web servers, require components that can dissipate heat efficiently. This requires materials capable of dissipating heat and maintaining compatibility with the packaging and dye. Its coverage includes all aspects of thermal management materials, both traditional and non-traditional, with an emphasis on metal based materials. An in-depth discussion of properties and m
Effect of heat treatment on mechanical dissipation in Ta$_2$O$_5$ coatings
Martin, I. W.; Bassiri, R.; Nawrodt, R.; Fejer, M. M.; Gretarsson, A.; Gustafson, E; Harry, G; Hough, J.; MacLaren, I.; Penn, S.; Reid, S.; Route, R; Rowan, S.; Schwarz, C; Seidel, P.
2010-01-01
Abstract Thermal noise arising from mechanical dissipation in dielectric reflective coatings is expected to critically limit the sensitivity of precision measurement systems such as high-resolution optical spectroscopy, optical frequency standards and future generations of interferometric gravitational wave detectors. We present measurements of the effect of post-deposition heat treatment on the temperature dependence of the mechanical dissipation in ion-beam sputtered tantalum pentoxide b...
Dilepton emission in high-energy heavy-ion collisions with dissipative hydrodynamics
Vujanovic, Gojko; Denicol, Gabriel S.; Shen, Chun; Luzum, Matthew; Schenke, Bjoern; Jeon, Sangyoung; Gale, Charles
2015-01-01
In this contribution we study the effects of three transport coefficients of dissipative hydrodynamics on thermal dilepton anisotropic flow observables. The first two transport coefficients investigated influence the overall size and growth rate of shear viscous pressure, while the last transport coefficient governs the magnitude of net baryon number diffusion in relativistic dissipative fluid dynamics. All calculations are done using state-of-the-art 3+1D hydrodynamical simulations. We show ...
Fluid particle dynamics: a synthesis of dissipative particle dynamics and smoothed particle dynamics
Español, Pep
1997-01-01
We present a generalization of dissipative particle dynamics that includes shear forces between particles. The new algorithm has the same structure as the (isothermal) smoothed particle dynamics algorithm, except that it conserves angular momentum and includes thermal fluctuations consistently with the principles of equilibrium statistical mechanics. This clarifies the connection of dissipative particle dynamics with numerical resolution algorithms of the macroscopic Navier-Stokes equations.
Directory of Open Access Journals (Sweden)
Rajneesh Kumar
2014-01-01
Full Text Available The reflection of plane waves at the free surface of thermally conducting micropolar elastic medium with two temperatures is studied. The theory of thermoelasticity with and without energy dissipation is used to investigate the problem. The expressions for amplitudes ratios of reflected waves at different angles of incident wave are obtained. Dissipation of energy and two-temperature effects on these amplitude ratios with angle of incidence are depicted graphically. Some special and particular cases are also deduced.
Siboni, Nachshon; Abrego, David; Evenhuis, Christian; Logan, Murray; Motti, Cherie A.
2015-12-01
Crustose coralline algae (CCA) are well known for their ability to induce settlement in coral larvae. While their wide distribution spans reefs that differ substantially in temperature regimes, the extent of local adaptation to these regimes and the impact they have on CCA inductive ability are unknown. CCA Porolithon onkodes from Heron (southern) and Lizard (northern) islands on Australia's Great Barrier Reef (separated by 1181 km) were experimentally exposed to acute or prolonged thermal stress events and their thermal tolerance and recruitment capacity determined. A sudden onset bleaching model was developed to determine the health status of CCA based on the rate of change in the CCA live surface area (LSA). The interaction between location and temperature was significant ( F (2,119) = 6.74, p = 0.0017), indicating that thermally driven local adaptation had occurred. The southern population remained healthy after prolonged exposure to 28 °C and exhibited growth compared to the northern population ( p = 0.022), with its optimum temperature determined to be slightly below 28 °C. As expected, at the higher temperatures (30 and 32 °C) the Lizard Island population performed better that those from Heron Island, with an optimum temperature of 30 °C. Lizard Island CCA displayed the lowest bleaching rates at 30 °C, while levels consistently increased with temperature in their southern counterparts. The ability of those CCA deemed thermally tolerant (based on LSA) to induce Acropora millepora larval settlement was then assessed. While spatial differences influenced the health and bleaching levels of P. onkodes during prolonged and acute thermal exposure, thermally tolerant fragments, regardless of location, induced similar rates of coral larval settlement. This confirmed that recent thermal history does not influence the ability of CCA to induce settlement of A. millepora larvae.
International Nuclear Information System (INIS)
Data envelopment analysis (DEA) has gained much popularity in performance measurement of power industry. This paper presents a slack-based measure approach to investigating the relationship between fossil fuel consumption and the environmental regulation of China's thermal power generation. We first calculate the total-factor energy efficiency without considering environmental constraints. An environmental performance indicator is proposed through decomposing the total-factor energy efficiency. The proposed approach is then employed to examine whether environmental regulation affects the energy efficiency of China's thermal power generation. We find that the environmental efficiency plays a significant role in affecting energy performance of China's thermal generation sector. Decreasing the discharge of major pollutants can improve both energy performance and environmental efficiency. Besides, we also have three main findings: (1) The energy efficiency and environmental efficiency were relatively low. (2) The energy and environmental efficiency scores show great variations among provinces. (3) Both energy efficiency and environmental efficiency are of obvious geographical characteristics. According to our findings, we suggest some policy implications. - Highlights: • We assess the energy efficiency and the environmental efficiency of China's thermal power generation simultaneously. • The energy efficiency and the environmental efficiency were relatively low during 2007–2009. • The energy efficiency and environmental efficiency show obvious geographic characters. • The environmental performance of a DMU plays a decisive role in the energy performance
Węglowski M. St.; Zeman M.; Grocholewski A.
2016-01-01
In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ) for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile...
Designing Biomimetic, Dissipative Material Systems
Energy Technology Data Exchange (ETDEWEB)
Balazs, Anna C. [Univ. of Pittsburgh, PA (United States). Chemical Engineering Dept.; Whitesides, George M. [Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry and Chemical Biology; Brinker, C. Jeffrey [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering. Dept. of Chemistry. Dept. of Molecular Genetics and Microbiology. Center for Micro-Engineered Materials; Aranson, Igor S. [UChicago, LLC., Argonne, IL (United States); Chaikin, Paul [New York Univ. (NYU), NY (United States). Dept. of Physics; Dogic, Zvonimir [Brandeis Univ., Waltham, MA (United States). Dept. of Physics; Glotzer, Sharon [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering. Dept. of Materials Science and Engineering. Dept. of Macromolecular Science and Engineering Physics; Hammer, Daniel [Univ. of Pennsylvania, Philadelphia, PA (United States). School of Engineering and Applied Science; Irvine, Darrell [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Materials Science and Engineering and Biological Engineering; Little, Steven R. [Univ. of Pittsburgh, PA (United States). Chemical Engineering Dept.; Olvera de la Cruz, Monica [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Parikh, Atul N. [Univ. of California, Davis, CA (United States). Dept. of Biomedical Engineering. Dept. of Chemical Engineering and Materials Science; Stupp, Samuel [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering. Dept. of Chemistry. Dept. of Medicine. Dept. of Biomedical Engineering; Szostak, Jack [Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry and Chemical Biology
2016-01-21
Throughout human history, new materials have been the foundation of transformative technologies: from bronze, paper, and ceramics to steel, silicon, and polymers, each material has enabled far-reaching advances. Today, another new class of materials is emerging—one with both the potential to provide radically new functions and to challenge our notion of what constitutes a “material”. These materials would harvest, transduce, or dissipate energy to perform autonomous, dynamic functions that mimic the behaviors of living organisms. Herein, we discuss the challenges and benefits of creating “dissipative” materials that can potentially blur the boundaries between living and non-living matter.
Natural approach to quantum dissipation
Taj, David; Öttinger, Hans Christian
2015-12-01
The dissipative dynamics of a quantum system weakly coupled to one or several reservoirs is usually described in terms of a Lindblad generator. The popularity of this approach is certainly due to the linear character of the latter. However, while such linearity finds justification from an underlying Hamiltonian evolution in some scaling limit, it does not rely on solid physical motivations at small but finite values of the coupling constants, where the generator is typically used for applications. The Markovian quantum master equations we propose are instead supported by very natural thermodynamic arguments. They themselves arise from Markovian master equations for the system and the environment which preserve factorized states and mean energy and generate entropy at a non-negative rate. The dissipative structure is driven by an entropic map, called modular, which introduces nonlinearity. The generated modular dynamical semigroup (MDS) guarantees for the positivity of the time evolved state the correct steady state properties, the positivity of the entropy production, and a positive Onsager matrix with symmetry relations arising from Green-Kubo formulas. We show that the celebrated Davies Lindblad generator, obtained through the Born and the secular approximations, generates a MDS. In doing so we also provide a nonlinear MDS which is supported by a weak coupling argument and is free from the limitations of the Davies generator.
Moving mirrors and the fluctuation-dissipation theorem
Stargen, D Jaffino; Sriramkumar, L
2016-01-01
We investigate the random motion of a mirror in (1 + 1)-dimensions that is immersed in a thermal bath of massless scalar particles which are interacting with the mirror through a boundary condition. Imposing the Dirichlet or the Neumann boundary conditions on the moving mirror, we evaluate the mean radiation reaction force on the mirror and the correlation function describing the fluctuations in the force about the mean value. From the correlation function thus obtained, we explicitly establish the fluctuation-dissipation theorem governing the moving mirror. Using the fluctuation-dissipation theorem, we compute the mean-squared displacement of the mirror at finite and zero temperature. We clarify a few points concerning the various limiting behavior of the mean-squared displacement of the mirror. While we recover the standard result at finite temperature, we find that the mirror diffuses logarithmically at zero temperature, confirming similar conclusions that have been arrived at earlier in this context. We a...
Power dissipation of air turbine VT - 400
Noga, Tomas; Žitek, Pavel
2016-06-01
This article provides an overview of ongoing systematic research of a turbine stage efficiency on a model air turbine VT 400. It contains an analysis of existing mathematical relations for a rotor friction dissipation calculation, on which basis a practical procedure of a calculation of those dissipations is recommended. Friction dissipations in the turbine rotor were divided into three main tasks: disc friction dissipations, shaft friction dissipations and dissipations in bearings. A contribution of performed work lies in the fact, that there is a dependence of rotor friction losses on its speed and a stage reaction has been revealed. This knowledge is completely essential for a further research, and will lead to more precise results of experiments. For the future, we plan to adjust the measuring track by adding a moment collar. We also assume an experimental verification of calculated friction losses.
Viscous Dissipation and Criticality of Subducting Slabs
Riedel, Mike; Karato, Shun; Yuen, Dave
2016-04-01
Rheology of subducting lithosphere appears to be complicated. In the shallow part, deformation is largely accomodated by brittle failure, whereas at greater depth, at higher confining pressures, ductile creep is expected to control slab strength. The amount of viscous dissipation ΔQ during subduction at greater depth, as constrained by experimental rock mechanics, can be estimated on the basis of a simple bending moment equation [1,2] 2ɛ˙0(z) ∫ +h/2 2 M (z) = h ṡ ‑h/2 4μ(y,z)y dy , (1) for a complex multi-phase rheology in the mantle transition zone, including the effects of a metastable phase transition as well as the pressure, temperature, grain-size and stress dependency of the relevant creep mechanisms; μ is here the effective viscosity and ɛ˙0(z) is a (reference) strain rate. Numerical analysis shows that the maximum bending moment, Mcrit, that can be sustained by a slab is of the order of 1019 Nm per m according to Mcrit˜=σp ∗h2/4, where σp is the Peierl's stress limit of slab materials and h is the slab thickness. Near Mcrit, the amount of viscous dissipation grows strongly as a consequence of a lattice instability of mantle minerals (dislocation glide in olivine), suggesting that thermo-mechanical instabilities become prone to occur at places where a critical shear-heating rate is exceeded, see figure. This implies that the lithosphere behaves in such cases like a perfectly plastic solid [3]. Recently available detailed data related to deep seismicity [4,5] seems to provide support to our conclusion. It shows, e.g., that thermal shear instabilities, and not transformational faulting, is likely the dominating mechanism for deep-focus earthquakes at the bottom of the transition zone, in accordance with this suggested "deep criticality" model. These new findings are therefore briefly outlined and possible implications are discussed. References [1] Riedel, M. R., Karato, S., Yuen, D. A. Criticality of Subducting Slabs. University of Minnesota
Viscous Dissipation and Criticality of Subducting Slabs
Riedel, Mike; Karato, Shun; Yuen, Dave
2016-04-01
Rheology of subducting lithosphere appears to be complicated. In the shallow part, deformation is largely accomodated by brittle failure, whereas at greater depth, at higher confining pressures, ductile creep is expected to control slab strength. The amount of viscous dissipation ΔQ during subduction at greater depth, as constrained by experimental rock mechanics, can be estimated on the basis of a simple bending moment equation [1,2] 2ɛ˙0(z) ∫ +h/2 2 M (z) = h ṡ -h/2 4μ(y,z)y dy , (1) for a complex multi-phase rheology in the mantle transition zone, including the effects of a metastable phase transition as well as the pressure, temperature, grain-size and stress dependency of the relevant creep mechanisms; μ is here the effective viscosity and ɛ˙0(z) is a (reference) strain rate. Numerical analysis shows that the maximum bending moment, Mcrit, that can be sustained by a slab is of the order of 1019 Nm per m according to Mcrit˜=σp ∗h2/4, where σp is the Peierl's stress limit of slab materials and h is the slab thickness. Near Mcrit, the amount of viscous dissipation grows strongly as a consequence of a lattice instability of mantle minerals (dislocation glide in olivine), suggesting that thermo-mechanical instabilities become prone to occur at places where a critical shear-heating rate is exceeded, see figure. This implies that the lithosphere behaves in such cases like a perfectly plastic solid [3]. Recently available detailed data related to deep seismicity [4,5] seems to provide support to our conclusion. It shows, e.g., that thermal shear instabilities, and not transformational faulting, is likely the dominating mechanism for deep-focus earthquakes at the bottom of the transition zone, in accordance with this suggested "deep criticality" model. These new findings are therefore briefly outlined and possible implications are discussed. References [1] Riedel, M. R., Karato, S., Yuen, D. A. Criticality of Subducting Slabs. University of Minnesota
Dissipation-induced instabilities and symmetry
Institute of Scientific and Technical Information of China (English)
Oleg N. Kirillov; Ferdinand Verhulst
2011-01-01
The paradox of destabilization of a conservative or non-conservative system by small dissipation, or Ziegler's paradox (1952), has stimulated a growing interest in the sensitivity of reversible and Hamiltonian systems with respect to dissipative perturbations. Since the last decade it has been widely accepted that dissipation-induced instabilities are closely related to singularities arising on the stability boundary, associated with Whitney's umbrella. The first explanation of Ziegler's paradox was given (much earlier) by Oene Bottema in 1956. The aspects of the mechanics and geometry of dissipation-induced instabilities with an application to rotor dynamics are discussed.
Dissipative heat engine is thermodynamically inconsistent
Makarieva, A M
2009-01-01
A heat engine operating on the basis of the Carnot cycle is considered, where the mechanical work performed is dissipated within the engine at the temperature of the warmer isotherm and the resulting heat is added to the engine together with an external heat input. The resulting work performed by the engine per cycle is increased at the expense of dissipated work produced in the previous cycle. It is shown that such a dissipative heat engine is thermodynamically inconsistent violating the first and second laws of thermodynamics. The existing physical models employing the dissipative heat engine concept, in particular, the heat engine model of hurricane development, are physically invalid.
Scaling laws for the upper ocean temperature dissipation rate
Bogucki, D.J.; Huguenard, K.; Haus, B.K.; Özgökmen, T.M.; Reniers, A.J.H.M.; Laxague, N.J.M.
2015-01-01
Our understanding of temperature dissipation rate χ within the upper ocean boundary layer, which is critical for climate forecasts, is very limited. Near-surface turbulence also affects dispersion of contaminants and biogeochemical tracers. Using high-resolution optical turbulence measurements, scaling laws for χ are investigated under forcing states where either the daytime heat flux or the wind stress forcing is dominant. We find that χ remains constant over 1.5 times the significant wave h...
Power dissipation characteristics of great power and super high speed semiconductor switch
International Nuclear Information System (INIS)
The power dissipation characteristics of pulsed power switch reversely switched dynistors (RSDs) are investigated in this paper. According to the expressions of voltage on RSD, derived from the plasma bipolar drift model and the RLC circuit equations of RSD main loop, the simulation waveforms of current and voltage on RSD are acquired through iterative calculation by using the fourth order Runge–Kutta method, then the curve of transient power on RSD versus time is obtained. The result shows that the total dissipation on RSD is trivial compared with the pulse discharge energy and the commutation dissipation can be nearly ignored compared with the quasi-static dissipation. These characteristics can make the repetitive frequency of RSD increase largely. The experimental results prove the validity of simulation calculations. The influence factors on power dissipation are discussed. The power dissipation increases with the increase of the peak current and the n-base width and with the decrease of n-base doping concentration. In order to keep a low power dissipation, it is suggested that the n-base width should be smaller than 320μm when doping concentration is 1.0×1014cm−3 while the doping concentration should be higher than 5.8×1013cm−3 when n-base width is 270μm. (condensed matter: structure, thermal and mechanical properties)
Internal dissipation of a polymer.
Deutsch, J M
2010-06-01
The dynamics of flexible polymer molecules are often assumed to be governed by hydrodynamics of the solvent. However there is considerable evidence that internal dissipation of a polymer contributes as well. Here we investigate the dynamics of a single chain in the absence of solvent to characterize the nature of this internal friction. We model the chains as freely hinged but with localized bond angles and threefold symmetric dihedral angles. We show that the damping is close but not identical to Kelvin damping, which depends on the first temporal and second spatial derivative of monomer position. With no internal potential between monomers, the magnitude of the damping is small for long wavelengths and weakly damped oscillatory time dependent behavior is seen for a large range of spatial modes. When the size of the internal potential is increased, such oscillations persist, but the damping becomes larger. However underdamped motion is present even with quite strong dihedral barriers for long enough wavelengths. PMID:20866433
Dissipative Shocks behind Bacteria Gliding
Virga, Epifanio G
2014-01-01
Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. We prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed.
Dissipative Dynamics of Quantum Fluctuations
Benatti, F; Floreanini, R
2015-01-01
One way to look for complex behaviours in many-body quantum systems is to let the number $N$ of degrees of freedom become large and focus upon collective observables. Mean-field quantities scaling as $1/N$ tend to commute, whence complexity at the quantum level can only be inherited from complexity at the classical level. Instead, fluctuations of microscopic observables scale as $1/\\sqrt{N}$ and exhibit collective Bosonic features, typical of a mesoscopic regime half-way between the quantum one at the microscopic level and the classical one at the level of macroscopic averages. Here, we consider the mesoscopic behaviour emerging from an infinite quantum spin chain undergoing a microscopic dissipative, irreversible dynamics and from global states without long-range correlations and invariant under lattice translations and dynamics. We show that, from the fluctuations of one site spin observables whose linear span is mapped into itself by the dynamics, there emerge bosonic operators obeying a mesoscopic dissipa...
Sharma, Reetu; Sastry, G Narahari
2015-01-01
Thermus thermophilius isopropylmalate dehydrogenase catalyzes oxidative decarboxylation and dehydrogenation of isopropylmalate. Substitution of leucine to alanine at position 172 enhances the thermal stability among the known point mutants. Exploring the dynamic properties of non-covalent interactions such as saltbridges, hydrogen bonds and hydrophobic interactions to explain thermal stability of a protein is interesting in its own right. In this study dynamic changes in the non-covalent interactions are studied to decipher the deterministic features of thermal stability of a protein considering a case study of a point mutant in Thermus thermophilus isopropylmalate dehydrogenase. A total of four molecular dynamic simulations of 0.2 μs were carried out on wild type and mutant's functional dimers at 300 K and 337 K. Higher thermal stability of the mutant as compared to wild type is revealed by root mean square deviation, root mean square fluctuations and Cα-Cα distance with an increase in temperature from 300 K to 337 K. Most of the regions of wild type fluctuate higher than the corresponding regions of mutant with an increase in temperature. Cα-Cα distance analysis suggests that long distance networks are significantly affected in wild type as compared to the mutant. Short lived contacts are higher in wild type, while long lived contacts are lost at 337 K. The mutant forms less hydrogen bonds with water as compared to wild type at 337 K. In contrast to wild type, the mutant shows significant increase in unique saltbridges, hydrogen bonds and hydrophobic contacts at 337 K. The current study indicates that there is a strong inter-dependence of thermal stability on the way in which non-covalent interactions reorganize, and it is rewarding to explore this connection in single mutant studies.
Directory of Open Access Journals (Sweden)
Reetu Sharma
Full Text Available Thermus thermophilius isopropylmalate dehydrogenase catalyzes oxidative decarboxylation and dehydrogenation of isopropylmalate. Substitution of leucine to alanine at position 172 enhances the thermal stability among the known point mutants. Exploring the dynamic properties of non-covalent interactions such as saltbridges, hydrogen bonds and hydrophobic interactions to explain thermal stability of a protein is interesting in its own right. In this study dynamic changes in the non-covalent interactions are studied to decipher the deterministic features of thermal stability of a protein considering a case study of a point mutant in Thermus thermophilus isopropylmalate dehydrogenase. A total of four molecular dynamic simulations of 0.2 μs were carried out on wild type and mutant's functional dimers at 300 K and 337 K. Higher thermal stability of the mutant as compared to wild type is revealed by root mean square deviation, root mean square fluctuations and Cα-Cα distance with an increase in temperature from 300 K to 337 K. Most of the regions of wild type fluctuate higher than the corresponding regions of mutant with an increase in temperature. Cα-Cα distance analysis suggests that long distance networks are significantly affected in wild type as compared to the mutant. Short lived contacts are higher in wild type, while long lived contacts are lost at 337 K. The mutant forms less hydrogen bonds with water as compared to wild type at 337 K. In contrast to wild type, the mutant shows significant increase in unique saltbridges, hydrogen bonds and hydrophobic contacts at 337 K. The current study indicates that there is a strong inter-dependence of thermal stability on the way in which non-covalent interactions reorganize, and it is rewarding to explore this connection in single mutant studies.
Robust dissipativity for uncertain impulsive dynamical systems
Directory of Open Access Journals (Sweden)
Liu Bin
2003-01-01
Full Text Available We discuss the robust dissipativity with respect to the quadratic supply rate for uncertain impulsive dynamical systems. By employing the Hamilton-Jacobi inequality approach, some sufficient conditions of robust dissipativity for this kind of system are established. Finally, we specialize the obtained results to the case of uncertain linear impulsive dynamical systems.
Symmetries of the dissipative Hofstadter model
Freed, D E
1993-01-01
The dissipative Hofstadter model, which describes a particle in 2-D subject to a periodic potential, uniform magnetic field, and dissipation, is also related to open string boundary states. This model exhibits an SL(2,Z) duality symmetry and hidden reparametrization invariance symmetries. These symmetries are useful for finding exact solutions for correlation functions.
Dissipation function in a magnetic field (Review)
Gurevich, V. L.
2015-07-01
The dissipation function is introduced to describe the behavior of the system of harmonic oscillations interacting with the environment (thermostat). This is a quadratic function of generalized velocities, which determines the rate of dissipation of the mechanical energy in the system. It was assumed earlier (Landau, Lifshitz) that the dissipation function can be introduced only in the absence of magnetic field. In the present review based on the author's studies, it has been shown how the dissipation function can be introduced in the presence of a magnetic field B. In a magnetic field, both dissipative and nondissipative responses arise as a response to perturbation and are expressed in terms of kinetic coefficients. The matrix of nondissipative coefficients can be obtained to determine an additional term formally including it into the equations of motion, which still satisfy the energy conservation law. Then, the dissipative part of the matrix can be considered in exactly the same way as without magnetic field, i.e., it defines the dissipation loss. As examples, the propagation and absorption of ultrasound in a metal or a semiconductor in a magnetic field have been considered using two methods: (i) the method based on the phenomenological theory using the equations of the theory of elasticity and (ii) the method based on the microscopic approach by analyzing and solving the kinetic equation. Both examples are used to illustrate the approach with the dissipation function.
Mid-Band Dissipative Spatial Solitons
Staliunas, Kestutis
2003-01-01
We show dissipative spatial solitons in nonlinear optical micro-resonators in which the refractive index is laterally modulated. In addition to "normal" and "staggered" dissipative solitons, similar to those in spatially modulated conservative systems, a narrow "mid-band" soliton is shown, having no counterparts in conservative systems.
Few-optical-cycle dissipative solitons
Energy Technology Data Exchange (ETDEWEB)
Leblond, H [Laboratoire de Photonique d' Angers EA 4464, Universite d' Angers, 2 Bd. Lavoisier, 49045 Angers Cedex 01 (France); Mihalache, D, E-mail: herve.leblond@univ-angers.f [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), 407 Atomistilor, Magurele-Bucharest, 077125 (Romania)
2010-09-17
By using a powerful reductive perturbation technique, or multiscale analysis, a generalized modified Korteweg-de Vries partial differential equation is derived, which describes the physics of few-optical-cycle dissipative solitons beyond the slowly varying envelope approximation. Numerical simulations of the formation of stable dissipative solitons from arbitrary breather-like few-cycle pulses are also given.
Calibration and temperature correction of heat dissipation matric potential sensors
Flint, A.L.; Campbell, G.S.; Ellett, K.M.; Calissendorff, C.
2002-01-01
This paper describes how heat dissipation sensors, used to measure soil water matric potential, were analyzed to develop a normalized calibration equation and a temperature correction method. Inference of soil matric potential depends on a correlation between the variable thermal conductance of the sensor's porous ceramic and matric poten-tial. Although this correlation varies among sensors, we demonstrate a normalizing procedure that produces a single calibration relationship. Using sensors from three sources and different calibration methods, the normalized calibration resulted in a mean absolute error of 23% over a matric potential range of -0.01 to -35 MPa. Because the thermal conductivity of variably saturated porous media is temperature dependent, a temperature correction is required for application of heat dissipation sensors in field soils. A temperature correction procedure is outlined that reduces temperature dependent errors by 10 times, which reduces the matric potential measurement errors by more than 30%. The temperature dependence is well described by a thermal conductivity model that allows for the correction of measurements at any temperature to measurements at the calibration temperature.
Minimising the heat dissipation of quantum information erasure
Hamed Mohammady, M.; Mohseni, Masoud; Omar, Yasser
2016-01-01
Quantum state engineering and quantum computation rely on information erasure procedures that, up to some fidelity, prepare a quantum object in a pure state. Such processes occur within Landauer's framework if they rely on an interaction between the object and a thermal reservoir. Landauer's principle dictates that this must dissipate a minimum quantity of heat, proportional to the entropy reduction that is incurred by the object, to the thermal reservoir. However, this lower bound is only reachable for some specific physical situations, and it is not necessarily achievable for any given reservoir. The main task of our work can be stated as the minimisation of heat dissipation given probabilistic information erasure, i.e., minimising the amount of energy transferred to the thermal reservoir as heat if we require that the probability of preparing the object in a specific pure state ≤ft|{\\varphi }1\\right.> be no smaller than {p}{\\varphi 1}{max}-δ . Here {p}{\\varphi 1}{max} is the maximum probability of information erasure that is permissible by the physical context, and δ ≥slant 0 the error. To determine the achievable minimal heat dissipation of quantum information erasure within a given physical context, we explicitly optimise over all possible unitary operators that act on the composite system of object and reservoir. Specifically, we characterise the equivalence class of such optimal unitary operators, using tools from majorisation theory, when we are restricted to finite-dimensional Hilbert spaces. Furthermore, we discuss how pure state preparation processes could be achieved with a smaller heat cost than Landauer's limit, by operating outside of Landauer's framework.
International Nuclear Information System (INIS)
The METER (Meteorological Effects of Thermal Energy Releases) Program was organized to develop and verify methods for predicting the maximum amount of energy that can be dissipated to the atmosphere (through cooling towers or cooling ponds) from proposed nuclear energy centers without affecting...the local and regional environment. The initial program scope (mathematical modeling, laboratory and field experimentation, and societal impact assessment) has now narrowed to emphasis on the acquisition of field data of substantial quality and extent
Material Systems for Blast-Energy Dissipation
Energy Technology Data Exchange (ETDEWEB)
James Schondel; Henry S. Chu
2010-10-01
Lightweight panels have been designed to protect buildings and vehicles from blast pressures by activating energy dissipation mechanisms under the influence of blast loading. Panels were fabricated which featured a variety of granular materials and hydraulic dissipative deformation mechanisms and the test articles were subjected to full-scale blast loading. The force time-histories transmitted by each technology were measured by a novel method that utilized inexpensive custom-designed force sensors. The array of tests revealed that granular materials can effectively dissipate blast energy if they are employed in a way that they easily crush and rearrange. Similarly, hydraulic dissipation can effectively dissipate energy if the panel features a high fraction of porosity and the panel encasement features low compressive stiffness.
Analytical study of dissipative solitary waves
Energy Technology Data Exchange (ETDEWEB)
Dini, Fatemeh [Department of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Emamzadeh, Mehdi Molaie [Department of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Khorasani, Sina [School of Electrical Engineering, Sharif University of Technology, PO Box 11365-363, Tehran (Iran, Islamic Republic of); Bobin, Jean Louis [Universite Pierre et Marie Curie, Paris (France); Amrollahi, Reza [Department of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Sodagar, Majid [School of Electrical Engineering, Sharif University of Technology, PO Box 11365-363, Tehran (Iran, Islamic Republic of); Khoshnegar, Milad [School of Electrical Engineering, Sharif University of Technology, PO Box 11365-363, Tehran (Iran, Islamic Republic of)
2008-02-15
In this paper, the analytical solution to a new class of nonlinear solitons is presented with cubic nonlinearity, subject to a dissipation term arising as a result of a first-order derivative with respect to time, in the weakly nonlinear regime. Exact solutions are found using the combination of the perturbation and Green's function methods up to the third order. We present an example and discuss the asymptotic behavior of the Green's function. The dissipative solitary equation is also studied in the phase space in the non-dissipative and dissipative forms. Bounded and unbounded solutions of this equation are characterized, yielding an energy conversation law for non-dissipative waves. Applications of the model include weakly nonlinear solutions of terahertz Josephson plasma waves in layered superconductors and ablative Rayleigh-Taylor instability.
Analytical study of dissipative solitary waves
International Nuclear Information System (INIS)
In this paper, the analytical solution to a new class of nonlinear solitons is presented with cubic nonlinearity, subject to a dissipation term arising as a result of a first-order derivative with respect to time, in the weakly nonlinear regime. Exact solutions are found using the combination of the perturbation and Green's function methods up to the third order. We present an example and discuss the asymptotic behavior of the Green's function. The dissipative solitary equation is also studied in the phase space in the non-dissipative and dissipative forms. Bounded and unbounded solutions of this equation are characterized, yielding an energy conversation law for non-dissipative waves. Applications of the model include weakly nonlinear solutions of terahertz Josephson plasma waves in layered superconductors and ablative Rayleigh-Taylor instability
SAITO Keiji; Kayanuma, Yosuke
2001-01-01
Dissipative effects on the nonadiabatic transition for the two and three level systems are studied. When the system is affected by a strong dissipation through the diabatic states, the exact transition probability is enumerated making use of the effective master equation. In the two-level system, we consider the case where the external field is swept from not only a negative large value but also from the resonant field, and the exact transition probabilities in these cases are derived. The tr...
Research on the Heat Dissipation Characteristics of Lithium Battery Spatial Layout in an AUV
Zhaoyong Mao; Shaokun Yan
2016-01-01
To meet the power demand requirements of autonomous underwater vehicles (AUVs), the power supply is generally composed of a large number of high-energy lithium battery groups. The lithium battery heat dissipation properties not only affect the underwater vehicle performance but also bring some security risks. Based on the widespread application of lithium batteries, lithium batteries in an AUV are taken as an example to investigate the heat dissipation characteristics of the lithium battery s...
Uncontrollable dissipative systems: observability and embeddability
Karikalan, Selvaraj; Belur, Madhu N.; Athalye, Chirayu D.; Razak, Rihab Abdul
2014-01-01
The theory of dissipativity is well developed for controllable systems. A more appropriate definition of dissipativity in the context of uncontrollable systems is in terms of the existence of a storage function, namely a function such that, along every system trajectory, its rate of change at each time instant is at most the power supplied to the system at that time. However, even when the supplied power is expressible in terms of just the external variables, the dissipativity property for uncontrollable systems crucially hinges on whether or not the storage function depends on variables unobservable/hidden from the external variables: this paper investigates the key aspects of both cases, and also proposes another intuitive definition of dissipativity. These three definitions are compared: we show that drawbacks of one definition are addressed by another. Dealing first with observable storage functions, under the conditions that no two uncontrollable poles add to zero and that dissipativity is strict as frequency tends to infinity, we prove that the dissipativities of a system and its controllable part are equivalent. We use the behavioural approach for formalising key notions: a system behaviour is the set of all system trajectories. We prove that storage functions have to be unobservable for 'lossless' uncontrollable systems. It is known, however, that unobservable storage functions result in certain 'fallacious' examples of lossless systems. We propose an intuitive definition of dissipativity: a system/behaviour is called dissipative if it can be embedded in a controllable dissipative superbehaviour. We prove embeddability results and use them to resolve the fallacy in the example termed 'lossless' due to unobservable storage functions. We next show that, quite unreasonably, the embeddability definition admits behaviours that are both strictly dissipative and strictly antidissipative. Drawbacks of the embeddability definition in the context of RLC circuits are
Characterization of a New Heat Dissipation Matric Potential Sensor
Rolf Krebs; Daniel Wächter; Luzius Matile; Roman Berger
2013-01-01
Soil moisture sensors can help to reduce the amount of water needed for irrigation. In this paper we describe the PlantCare soil moisture sensor as a new type of heat dissipation sensor, its calibration and the correction for temperature changes. With the PlantCare sensor it is possible to measure the matric potential indirectly to monitor or control irrigation. This sensor is based on thermal properties of a synthetic felt. After a defined heating phase the cooling time to a threshold temper...
Energy Technology Data Exchange (ETDEWEB)
Gegner, Juergen [SKF GmbH, Dept. of Material Physics, Schweinfurt (Germany)
2009-07-01
After heat treatment, finish machining of the hardened steel represents the last manufacturing step of machine elements. The practically most important operation of grinding is applied to achieve edge zone compressive residual stresses, best surface quality and dimensional accuracy. Metal removal involves high plastic deformation work. Glide and intersection processes raise the density and produce lower energy substructures of dislocations. The temperature and time behavior of post-machining thermal treatment is analyzed on ground and honed martensitic SAE 52100 rolling bearing steel. Microstructure stabilization is reflected in a large XRD line width decrease on the surface. The kinetics is modeled by rate-controlling carbide dissolution as the carbon source for Cottrell-type segregation at dislocations. This static strain aging is verified by the formation of a slight white etching surface layer. The metal physics model is extended to also consider superimposed thermal dislocation recovery. Both effects are separable. In rolling contact fatigue tests under mixed friction running conditions, air reheating of the samples below the tempering temperature, which avoids hardness loss, leads to a significant lifetime increase. Thermal post-treatment after cold working results in similar changes of the XRD line width in the larger mechanically affected edge zone.
Directory of Open Access Journals (Sweden)
Węglowski M. St.
2016-03-01
Full Text Available In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists.
FEA based Dissipation Energy and Temperature Distribution of Rubber Bushing
Directory of Open Access Journals (Sweden)
Zhengui Zhanga ,
2016-01-01
Full Text Available Rubber bushings used in the vehicle or aerospace can reduce the noise and vibration and absorb the shocks. The heat accumulation in the rubber components is attributed to the nonlinear mechanical behavior of rubber and leads to degeneration of mechanical properties. The viscoelastic damping is treated as the major mechanism of dissipation energy, which is heat source of temperature rising in bushing. A finite element method is expanded from elastic structure to viscoelastic structure and computes the dissipation energy distribution in the rubber core. Based on that heat source, the temperature distribution of rubber bushing under radial harmonic excitation has been calculated using finite volume method. The frequency and amplitude effect on dissipation energy and temperature distribution are described. The radial dynamic testing is carried out and the temperature is recorded using thermal imager to evaluate the simulation. As complement, the dynamic torsional testing is also carried out explore the possible failure zone of rubber bushing under different types of loading.
Heat dissipation during hovering and forward flight in hummingbirds.
Powers, Donald R; Tobalske, Bret W; Wilson, J Keaton; Woods, H Arthur; Corder, Keely R
2015-12-01
Flying animals generate large amounts of heat, which must be dissipated to avoid overheating. In birds, heat dissipation is complicated by feathers, which cover most body surfaces and retard heat loss. To understand how birds manage heat budgets during flight, it is critical to know how heat moves from the skin to the external environment. Hummingbirds are instructive because they fly at speeds from 0 to more than 12 m s(-1), during which they transit from radiative to convective heat loss. We used infrared thermography and particle image velocimetry to test the effects of flight speed on heat loss from specific body regions in flying calliope hummingbirds (Selasphorus calliope). We measured heat flux in a carcass with and without plumage to test the effectiveness of the insulation layer. In flying hummingbirds, the highest thermal gradients occurred in key heat dissipation areas (HDAs) around the eyes, axial region and feet. Eye and axial surface temperatures were 8°C or more above air temperature, and remained relatively constant across speeds suggesting physiological regulation of skin surface temperature. During hovering, birds dangled their feet, which enhanced radiative heat loss. In addition, during hovering, near-body induced airflows from the wings were low except around the feet (approx. 2.5 m s(-1)), which probably enhanced convective heat loss. Axial HDA and maximum surface temperature exhibited a shallow U-shaped pattern across speeds, revealing a localized relationship with power production in flight in the HDA closest to the primary flight muscles. We conclude that hummingbirds actively alter routes of heat dissipation as a function of flight speed.
Institute of Scientific and Technical Information of China (English)
Maite MART(I)NEZ-EIXARCH; ZHU De-feng; Maria del Mar CATAL(A)-FORNER; Eva PLA-MAYOR; Nuria TOM(A)S-NAVARRO
2013-01-01
Field experiments were conducted in the Ebro Delta area (Spain),from 2007 to 2009 with two rice varieties:Gleva and Tebre.The experimental treatments included a series of seed rates,two different water management systems and two different nitrogen fertilization times.The number of leaves on the main stems and their emergence time were periodically tagged.The results indicated that the final leaf number on the main stems in the two rice varieties was quite stable over a three-year period despite of the differences in their respective growth cycles.Interaction between nitrogen fertilization and water management influenced the final leaf number on the main stems.Plant density also had a significant influence on the rate of leaf appearance by extending the phyllochron and postponing the onset of intraspecific competition after the emergence of the 7th leaf on the main stems.Final leaf number on the main stems was negatively related to plant density.A relationship between leaf appearance and thermal time was established with a strong nonlinear function.In direct-seeded rice,the length of the phyllochron increases exponentially in line with the advance of plant development.A general model,derived from 2-year experimental data,was developed and satisfactorily validated; it had a root mean square error of 0.3 leaf.An exponential model can be used to predict leaf emergence in direct-seeded rice.
Pantazopoulos, George; Toulfatzis, Anagnostis; Zormalia, Sylvia; Vazdirvanidis, Athanasios; Skarmoutsos, Dionysios
2012-10-01
The influence of heat treatment conditions on the mechanical behavior and microstructure of CuFe2P (ASTM C19400) in comparison to deoxidized-high-phosphorus (DHP-Cu/ASTM C12200) tubes was investigated. The aim of this study was the enhancement of understanding of microstructure/thermal treatment/strength relationships which could be further utilized for the manufacturing of components exhibiting superior performance and reliability for refrigeration and heat exchanger applications. Microstructural examination employing optical metallography and scanning electron microscopy is used for the evaluation of the recrystallization progress and grain growth processes. In addition, tensile testing was conducted to CuFe2P and DHP tubes following the application of heat treatment cycles, in accordance to the EN 10002-1 specifications. Mechanical properties and microstructure evaluation showed that CuFe2P material is fully recrystallized at 740 °C and DHP at 400 °C for 20 min. Recrystallization initiation varies within the range of 640-660 °C for CuFe2P and below 400 °C for DHP tubes. The tensile strength of the CuFe2P tube decreased from 513 to 367 MPa, the hardness was reduced from 144 to 126 HV, while tensile elongation was significantly improved from 3 to 17%. At 640 °C, only isolated recrystallized areas were evident mainly at the Fe-based intermetallic particle/copper matrix interface areas.
Constructal optimization on T-shaped cavity based on entransy dissipation minimization
Institute of Scientific and Technical Information of China (English)
XIE ZhiHui; CHEN LinGen; SUN FengRui
2009-01-01
The entransy dissipation extremum principle provides new warranty and criterion for optimization of heat transfer. For a heat transfer model of a rectangular solid wall with an open T-shaped cavity, a di-mensionless equivalent thermal resistance based on entransy dissipation is taken as optimization ob-jective, and constructal optimization for the model is carried out when the system volume, the cavity volume and the volume of rectangle occupied by T-shaped cavity are fixed. Numerical results indicate that the optimal geometry construct of cavity can be schemed out based on entransy dissipation ex-tremum principle. The formulation of dimensionless global (maximum) thermal resistance presented in a literature is modified; some new rules which are different from those reported in the literature are obtained based on the minimization of the modified objective. Comparisons of the numerical results show that the optimal system constructs deduced respectively from the two thermal resistance objec-tives are very different. The optimization by taking equivalent thermal resistance minimization as ob-jective can more effectively reduce mean temperature difference of heat transfer than the optimization by taking maximum thermal resistance minimization as objective, so that the performance of heat transfer for the total system can be improved. The more freedom the cavity has, the better the total system performance is. The correlations of the equivalent thermal resistance and the maximum thermal resistance of the system and three geometric degrees of freedom are found by using function fitting.
Loyau, T; Berri, C; Bedrani, L; Métayer-Coustard, S; Praud, C; Duclos, M J; Tesseraud, S; Rideau, N; Everaert, N; Yahav, S; Mignon-Grasteau, S; Collin, A
2013-08-01
Selection in broiler chickens has increased muscle mass without similar development of the cardiovascular and respiratory systems, resulting in limited ability to sustain high ambient temperatures. The aim of this study was to determine the long-lasting effects of heat manipulation of the embryo on the physiology, body temperature (Tb), growth rate and meat processing quality of broiler chickens reared in floor pens. Broiler chicken eggs were incubated in control conditions (37.8°C, 56% relative humidity; RH) or exposed to thermal manipulation (TM; 12 h/d, 39.5°C, 65% RH) from d 7 to 16 of embryogenesis. This study was planned in a pedigree design to identify possible heritable characters for further selection of broiler chickens to improve thermotolerance. Thermal manipulation did not affect hatchability but resulted in lower Tb at hatching and until d 28 post-hatch, with associated changes in plasma thyroid hormone concentrations. At d 34, chickens were exposed to a moderate heat challenge (5 h, 32°C). Greater O2 saturation and reduced CO2 partial pressure were observed (P slaughter age, TM chickens were 1.4% lighter and exhibited 8% less relative abdominal fat pad than controls. Breast muscle yield was enhanced by TM, especially in females, but without significant change in breast meat characteristics (pH, color, drip loss). Plasma glucose/insulin balance was affected (P 0.17). In conclusion, TM of the embryo modified the physiology of broilers in the long term as a possible adaptation for heat tolerance, without affecting breast meat quality. This study highlights the value of 2 new heritable characters involved in thermoregulation for further broiler selection. PMID:23736053
ATOMIZATION CAUSED BY BOTTOM FLOW ENERGY DISSIPATION
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Bottom flow energy dissipation is one of the common energydissipation methods for flood-releasing structures with high water head. Measures of this energy dissipation depend mainly on the turbulent action of hydraulic jump.In this paper, the physical process and the calculating methods of the atomization caused by bottom flow energy dissipation were studied, the computation models of atomization quantity for the self-aerated flow in overflow and hydraulic jump regions are presented, and the main results are of theoretical and practical significance for the hydraulic and electric engineering.
Multicritical behavior in dissipative Ising models
Overbeck, Vincent R; Gorshkov, Alexey V; Weimer, Hendrik
2016-01-01
We analyze theoretically the many-body dynamics of a dissipative Ising model in a transverse field using a variational approach. We find that the steady state phase diagram is substantially modified compared to its equilibrium counterpart, including the appearance of a multicritical point belonging to a different universality class. Building on our variational analysis, we establish a field-theoretical treatment corresponding to a dissipative variant of a Ginzburg-Landau theory, which allows us to compute the upper critical dimension of the system. Finally, we present a possible experimental realization of the dissipative Ising model using ultracold Rydberg gases.
Institute of Scientific and Technical Information of China (English)
LIU Hai-ying
2008-01-01
By introducing the concepts of stably dissipative matrix and graph, some criteria conditions for stably dissipative matrix were given. On this basis, the method of graph theory was used to classify all stably dissipative 3D Lotka-Volterra systems and five classes of maximal stably dissipative graphs were obtained for these systems. Finally, the necessary and sufficient condition of being stably dissipative for every class was studied, under which the matrix associated with the graph is stably dissipative.
Heat dissipation from carbon nano-electronics
Ong, Zhun Yong
2011-12-01
The incorporation of graphitic compounds such as carbon nanotubes (CNTs) and graphene into nano-electronic device packaging holds much promise for waste heat management given their high thermal conductivities. However, as these graphitic materials must be used in together with other semiconductor/insulator materials, it is not known how thermal transport is affected by the interaction. Using different simulation techniques, in this thesis, we evaluate the thermal transport properties --- thermal boundary conductance (TBC) and thermal conductivity --- of CNTs and single-layer graphene in contact with an amorphous SiO2 (a-SiO2) substrate. First, the theoretical methodologies and concepts used in our simulations are presented. In particular, two concepts are described in detail as they are necessary for the understanding of the subsequent chapters. The first is the linear response Green-Kubo (GK) theory of thermal boundary conductance (TBC), which we develop in this thesis, and the second is the spectral energy density method, which we use to directly compute the phonon lifetimes and thermal transport coefficients. After we set the conceptual foundations, the TBC of the CNT-SiO 2 interface is computed using non-equilibrium molecular dynamics (MD) simulations and the new Green-Kubo method that we have developed. Its dependence on temperature, the strength of the interaction with the substrate, and tube diameter are evaluated. To gain further insight into the phonon dynamics in supported CNTs, the scattering rates are computed using the spectral energy density (SED) method. With this method, we are able to distinguish the different scattering mechanisms (boundary and CNT-substrate phonon-phonon) and rates. The phonon lifetimes in supported CNTs are found to be reduced by contact with the substrate and we use that lifetime reduction to determine the change in CNT thermal conductivity. Next, we examine thermal transport in graphene supported on SiO 2. The phonon
Segal, M.; Arritt, R. W.; Tillman, J. E.
1997-01-01
The Martian daytime soil surface temperature is governed primarily by the net irradiance balance and surface soil heat flux. Thus the outbreak of a cold air mass generates increased sensible heat flux that is conducive to daytime dissipation of the cold air mass thermal characteristics. Conceptual and scaling evaluations of this dissipation are provided while comparison is made with similar situations on Earth. It is estimated that sensible heat flux contribution to the dissipation of the original thermal structure of the cold air could be three times larger than the corresponding situation on Earth. Illustrative numerical model simulations provide scaling of the potential impact on the dissipation of cold air masses for various combinations of background wind speed and latitudes.
Multiwalled Carbon Nanotube Nanofluids Used for Heat Dissipation in Hybrid Green Energy Systems
Directory of Open Access Journals (Sweden)
Yi-Hsuan Hung
2014-01-01
Full Text Available This study was conducted to characterize carbon nanotube (CNT/water nanofluids (CNWNFs and to apply the nanofluids in a heat-dissipation system of dual green energy sources. CNTs were mixed with water in weight fractions of 0.125%, 0.25%, and 0.5% to produce nanofluids. The thermal conductivity, density, viscosity, and specific heat of the nanofluids were measured. An experimental platform consisting of a simulated dual energy source and a microchip controller was established to evaluate the heat-dissipation performance. Two indices, the heat dissipation enhancement ratio and specific heat dissipation enhancement ratio (SHDER, were defined and calculated. The CNWNFs with a CNT concentration of 0.125 wt.% were used because they exhibited the highest SHDER. The steady-state performance was evaluated at 2 flow rates, 11 hybrid flow ratios, and 3 heating ratios for a total power of 1000 W. The transient behavior of the energy sources at preset optimal temperatures was examined, and the CNWNFs exhibited average increases in stability and heat dissipation efficiency of 36.2% and 5%, respectively, compared with water. This nanofluid heat-dissipation system is expected to be integrated with real dual energy sources in the near future.
Multiscale simulation of ideal mixtures using smoothed dissipative particle dynamics
Petsev, Nikolai D.; Leal, L. Gary; Shell, M. Scott
2016-02-01
Smoothed dissipative particle dynamics (SDPD) [P. Español and M. Revenga, Phys. Rev. E 67, 026705 (2003)] is a thermodynamically consistent particle-based continuum hydrodynamics solver that features scale-dependent thermal fluctuations. We obtain a new formulation of this stochastic method for ideal two-component mixtures through a discretization of the advection-diffusion equation with thermal noise in the concentration field. The resulting multicomponent approach is consistent with the interpretation of the SDPD particles as moving volumes of fluid and reproduces the correct fluctuations and diffusion dynamics. Subsequently, we provide a general multiscale multicomponent SDPD framework for simulations of molecularly miscible systems spanning length scales from nanometers to the non-fluctuating continuum limit. This approach reproduces appropriate equilibrium properties and is validated with simulation of simple one-dimensional diffusion across multiple length scales.
Multiscale simulation of ideal mixtures using smoothed dissipative particle dynamics.
Petsev, Nikolai D; Leal, L Gary; Shell, M Scott
2016-02-28
Smoothed dissipative particle dynamics (SDPD) [P. Español and M. Revenga, Phys. Rev. E 67, 026705 (2003)] is a thermodynamically consistent particle-based continuum hydrodynamics solver that features scale-dependent thermal fluctuations. We obtain a new formulation of this stochastic method for ideal two-component mixtures through a discretization of the advection-diffusion equation with thermal noise in the concentration field. The resulting multicomponent approach is consistent with the interpretation of the SDPD particles as moving volumes of fluid and reproduces the correct fluctuations and diffusion dynamics. Subsequently, we provide a general multiscale multicomponent SDPD framework for simulations of molecularly miscible systems spanning length scales from nanometers to the non-fluctuating continuum limit. This approach reproduces appropriate equilibrium properties and is validated with simulation of simple one-dimensional diffusion across multiple length scales. PMID:26931689
Quantum Phase Transition, Dissipation, and Measurement
Chakravarty, Sudip
2009-01-01
A selected set of topics in quantum phase transition is discussed. It includes dissipative quantum phase transitions, the role of disorder, and the relevance of quantum phase transition to measurement theory in quantum mechanics.
Towards a Measurement of the Spacetime Dissipation
Yang, Huan; Smith, Nicolas D; Adhikari, Rana X; Miao, Haixing; Chen, Yanbei
2015-01-01
It has been speculated that gravity could be an emergent phenomenon, with classical general relativity as an effective, macroscopic theory, valid only for classical systems at large temporal and spatial scales. As in classical continuum dynamics, the existence of underlying microscopic degrees of freedom may lead to macroscopic dissipative behaviors. With the hope that such dissipative behaviors of gravity could be revealed by carefully designed experiments in the laboratory, we consider a family of phenomenological models that add dissipations to the gravitational field, much similar to frictions in solids and fluids. Constraints to such dissipative behavior can already be imposed by astrophysical observations and existing experiments, but mostly in lower frequencies. We propose a series of experiments working in higher frequency regimes, which may potentially put more stringent bounds on these models.
Characterizing pesticide dissipation in food crops
DEFF Research Database (Denmark)
Fantke, Peter; Juraske, R.; Jolliet, O.
2013-01-01
Ingestion of residues via consumption of food crops is the predominant exposure route of the general population toward pesticides. However, pesticide dissipation in crops constitutes a main source of uncertainty in estimating residues in harvested crop parts and subsequent human exposure. Neverth......Ingestion of residues via consumption of food crops is the predominant exposure route of the general population toward pesticides. However, pesticide dissipation in crops constitutes a main source of uncertainty in estimating residues in harvested crop parts and subsequent human exposure....... Nevertheless, dissipation is a key mechanism in models assessing pesticide distribution in the cropenvironment and the magnitude of residues in harvest. We provide a consistent framework for characterizing pesticide dissipation in food crops for use in modeling approaches applied in health risk and impact...
Dissipation effects in mechanics and thermodynamics
Güémez, J.; Fiolhais, M.
2016-07-01
With the discussion of three examples, we aim at clarifying the concept of energy transfer associated with dissipation in mechanics and in thermodynamics. The dissipation effects due to dissipative forces, such as the friction force between solids or the drag force in motions in fluids, lead to an internal energy increase of the system and/or to heat transfer to the surroundings. This heat flow is consistent with the second law, which states that the entropy of the universe should increase when those forces are present because of the irreversibility always associated with their actions. As far as mechanics is concerned, the effects of the dissipative forces are included in Newton’s equations as impulses and pseudo-works.
Dissipation effects in mechanics and thermodynamics
Guemez, Julio
2016-01-01
With the discussion of three examples, we aim at clarifying the concept of energy transfer associated with dissipation in mechanics and in thermodynamics. The dissipation effects due to dissipative forces, such as the friction force between solids or the drag force in motions in fluids, lead to an internal energy increase of the system and/or to a heat transfer to the surrounding. This heat flow is consistent with the second law, which states that the entropy of the universe should increase when those forces are present because of the irreversibility always associated with their actions. As far as mechanics is concerned the effects of the dissipative forces are include in the Newton's equations as impulses and pseudo-works.
Precisely timing dissipative quantum information processing
Kastoryano, M J; Eisert, J
2012-01-01
Dissipative engineering constitutes a framework within which quantum information processing protocols are powered by weak (Markovian) system-environment interaction rather than by unitary dynamics alone. This framework embraces noise as a resource, and consequently, offers a number of advantages compared to one based on unitary dynamics alone, e.g., that large classes of initial states are rapidly driven to desirable steady states. One apparent drawback of this scheme is that it does not seem to allow for precisely timed sequential operations, conditional measurements or error correction. In this work, we provide a solution to these challenges, by introducing some basic dissipative gadgets which allow us to precisely initiate, trigger and time dissipative operations, while keeping the system Liouvillian time independent. These gadgets open up novel perspectives for thinking of timed, protected dissipative quantum information processing. As an example, we sketch how universal computation can be performed with ...
Open Boundary Conditions for Dissipative MHD
Energy Technology Data Exchange (ETDEWEB)
Meier, E T
2011-11-10
In modeling magnetic confinement, astrophysics, and plasma propulsion, representing the entire physical domain is often difficult or impossible, and artificial, or 'open' boundaries are appropriate. A novel open boundary condition (BC) for dissipative MHD, called Lacuna-based open BC (LOBC), is presented. LOBC, based on the idea of lacuna-based truncation originally presented by V.S. Ryaben'kii and S.V. Tsynkov, provide truncation with low numerical noise and minimal reflections. For hyperbolic systems, characteristic-based BC (CBC) exist for separating the solution into outgoing and incoming parts. In the hyperbolic-parabolic dissipative MHD system, such separation is not possible, and CBC are numerically unstable. LOBC are applied in dissipative MHD test problems including a translating FRC, and coaxial-electrode plasma acceleration. Solution quality is compared to solutions using CBC and zero-normal derivative BC. LOBC are a promising new open BC option for dissipative MHD.
Shock instability in dissipative gases
Radulescu, Matei I.; Sirmas, Nick
2011-01-01
Previous experiments have revealed that shock waves in thermally relaxing gases, such as ionizing, dissociating and vibrationally excited gases, can become unstable. To date, the mechanism controlling this instability has not been resolved. Previous accounts of the D'yakov-Kontorovich instability, and Bethe-Zel'dovich-Thompson behaviour could not predict the experimentally observed instability. To address the mechanism controlling the instability, we study the propagation of shock waves in a ...
Local mapping of dissipative vortex motion
Raes, Bart; Van de Vondel, Joris; Silhanek, A. V; de Souza Silva, C.C.; Gutierrez, J; Kramer, R. B. G.; Moshchalkov, Victor
2012-01-01
We explore, with unprecedented single vortex resolution, the dissipation and motion of vortices in a superconducting ribbon under the influence of an external alternating magnetic field. This is achieved by combining the phase sensitive character of ac susceptibility, allowing us to distinguish between the inductive and dissipative responses, with the local power of scanning Hall probe microscopy. Whereas the induced reversible screening currents contribute only inductively, the vortices do l...
Heat dissipation guides activation in signaling proteins
Weber, Jeffrey K.; Shukla, Diwakar; Pande, Vijay S.
2015-01-01
As with their macroscopic counterparts, the moving parts of nanoscale protein machines grow hot while in operation. A portion of the energy biomolecules harness to perform meaningful work is always dissipated as heat into the surroundings. Here, we feature a methodology by which dominant dissipative trajectories can be extracted from detailed models of protein dynamics. In two important classes of signaling proteins [kinases and G-protein–coupled receptors (GPCRs)], we find that the regions o...
Energy dissipation in multifrequency atomic force microscopy.
Pukhova, Valentina; Banfi, Francesco; Ferrini, Gabriele
2014-01-01
The instantaneous displacement, velocity and acceleration of a cantilever tip impacting onto a graphite surface are reconstructed. The total dissipated energy and the dissipated energy per cycle of each excited flexural mode during the tip interaction is retrieved. The tip dynamics evolution is studied by wavelet analysis techniques that have general relevance for multi-mode atomic force microscopy, in a regime where few cantilever oscillation cycles characterize the tip-sample interaction. PMID:24778976
Energy dissipation in multifrequency atomic force microscopy
Directory of Open Access Journals (Sweden)
Valentina Pukhova
2014-04-01
Full Text Available The instantaneous displacement, velocity and acceleration of a cantilever tip impacting onto a graphite surface are reconstructed. The total dissipated energy and the dissipated energy per cycle of each excited flexural mode during the tip interaction is retrieved. The tip dynamics evolution is studied by wavelet analysis techniques that have general relevance for multi-mode atomic force microscopy, in a regime where few cantilever oscillation cycles characterize the tip–sample interaction.
Harmonic Oscillator Potential to describe Internal Dissipation
Peters, R D
2003-01-01
Assuming that a constant potential energy function has meaning for a dissipated harmonic oscillator, then an important issue is the time dependence of the turning points. Turning point studies demonstrate that the common model of external (viscous) damping fails to properly describe those many systems where structural (internal friction) damping is the most important source of dissipation. For internal friction damping, the better model of potential energy is one in which the function is not stationary.
Dissipative electromagnetism from a nonequilibrium thermodynamics perspective
Jelic, A; Hütter, M Markus; Öttinger, HC
2006-01-01
Dissipative effects in electromagnetism on macroscopic scales are examined by coarse graining the microscopic Maxwell equations with respect to time. We illustrate a procedure to derive the dissipative effects on the macroscopic scale by using a Green-Kubo type expression in terms of the microscopic fluctuations and the correlations between them. The resulting macroscopic Maxwell equations are formulated within the General Equation for the Non-Equilibrium Reversible-Irreversible Coupling (GEN...
Dissipation, correlation and lags in heat engines
Campisi, Michele; Fazio, Rosario
2016-08-01
By modelling heat engines as driven multi-partite system we show that their dissipation can be expressed in terms of the lag (relative entropy) between the perturbed state of each partition and their equilibrium state, and the correlations that build up among the partitions. We show that the non-negativity of the overall dissipation implies Carnot formulation of the second law. We illustrate the rich interplay between correlations and lags with a two-qubit device driven by a quantum gate.
Metriplectic framework for dissipative magneto-hydrodynamics
M. Materassi; Tassi, Emanuele
2012-01-01
The metriplectic framework, which allows for the formulation of an algebraic structure for dissipative systems, is applied to visco-resistive Magneto-Hydrodynamics (MHD), adapting what had already been done for non-ideal Hydrodynamics (HD). The result is obtained by extending the HD symmetric bracket and free energy to include magnetic field dynamics and resistive dissipation. The correct equations of motion are obtained once one of the Casimirs of the Poisson bracket for ideal MHD is identif...
Unravelling tidal dissipation in gaseous giant planets
Guenel, Mathieu; Remus, Françoise
2014-01-01
Tidal dissipation in planetary interiors is one of the key physical mechanisms that drive the evolution of star-planet and planet-moon systems. New constraints are now obtained both in the Solar and exoplanetary systems. Tidal dissipation in planets is intrinsically related to their internal structure. In particular, fluid and solid layers behave differently under tidal forcing. Therefore, their respective dissipation reservoirs have to be compared. In this letter, we compute separately the contributions of the potential dense rocky/icy core and the convective fluid envelope of gaseous giant planets, as a function of core size and mass. We then compare the associated dissipation reservoirs, by evaluating the frequency-average of the imaginary part of the Love numbers $k^2_2$ in each region. In the case of Jupiter and Saturn-like planets, we show that the viscoelastic dissipation in the core could dominate the turbulent friction acting on tidal inertial waves in the envelope. However, the fluid dissipation wou...
Dissipative hydrodynamics in 2+1 dimension
Chaudhuri, A K
2006-01-01
In 2+1 dimension, we have simulated the hydrodynamic evolution of QGP fluid with dissipation due to shear viscosity. Comparison of evolution of ideal and viscous fluid, both initialised under the same conditions e.g. same equilibration time, energy density and velocity profile, reveal that the dissipative fluid evolve slowly, cooling at a slower rate. Cooling get still slower for higher viscosity. The fluid velocities on the otherhand evolve faster in a dissipative fluid than in an ideal fluid. The transverse expansion is also enhanced in dissipative evolution. For the same decoupling temperature, freeze-out surface for a dissipative fluid is more extended than an ideal fluid. Dissipation produces entropy as a result of which particle production is increased. Particle production is increased due to (i) extension of the freeze-out surface and (ii) change of the equilibrium distribution function to a non-equilibrium one, the last effect being prominent at large transverse momentum. Compared to ideal fluid, tran...
Energy Technology Data Exchange (ETDEWEB)
Paul Meakin; Zhijie Xu
2009-08-01
Particle methods are less computationally efficient than grid based numerical solution of the Navier Stokes equation. However, they have important advantages including rigorous mass conservation, momentum conservation and isotropy. In addition, there is no need for explicit interface tracking/capturing and code development effort is relatively low. We describe applications of three particle methods: molecular dynamics, dissipative particle dynamics and smoothed particle hydrodynamics. The mesoscale (between the molecular and continuum scales) dissipative particle dynamics method can be used to simulate systems that are too large to simulate using molecular dynamics but small enough for thermal fluctuations to play an important role.
Analysing half-lives for pesticide dissipation in plants
DEFF Research Database (Denmark)
Jacobsen, R.E.; Fantke, Peter; Trapp, Stefan
2015-01-01
and calculated dissipation by non-degradative processes should ideally be contributable to degradation in plants. In 11% of the cases, calculated dissipation was above the measured dissipation. For the remaining cases, the non-explained dissipation ranged from 30% to 83%, depending on crop type, plant part...
Thin layer structure of dissipation rate of scalar turbulence
Institute of Scientific and Technical Information of China (English)
ZHOU; Haibing; (周海兵); CUI; Guixiang; (崔桂香); XU; Chunxiao; (许春晓); ZHANG; Zhaoshun; (张兆顺)
2003-01-01
The structure of scalar turbulence dissipation is studied by means of direct numerical simulation. It has been discovered that the scalar turbulence dissipation exhibits thin layer structure. Based on the analysis of transportation equation of scalar turbulence dissipation, we have investigated the effect of turbulent strains on the generation of scalar turbulence dissipation and found that fluctuating scalar gradients trend to the third principal direction of turbulent strains. Therefore the generation of the thin layer structure of scalar turbulence dissipation is well interpreted.
Shome, M.; Gupta, O. P.; Mohanty, O. N.
2004-03-01
The influence of weld thermal simulation on the transformation kinetics and heat-affected zone (HAZ) microstructure of two high-strength low-alloy (HSLA) steels, HSLA-80 and HSLA-100, has been investigated. Heat inputs of 10 kJ/cm (fast cooling) and 40 kJ/cm (slow cooling) were used to generate single-pass thermal cycles with peak temperatures in the range of 750 °C to 1400 °C. The prior-austenite grain size is found to grow rapidly beyond 1100 °C in both the steels, primarily with the dissolution of niobium carbonitride (Nb(CN)) precipitates. Dilatation studies on HSLA-80 steel indicate transformation start temperatures (T s ) of 550 °C to 560 °C while cooling from a peak temperature (T p ) of 1000 °C. Transmission electron microscopy studies show here the presence of accicular ferrite in the HAZ. The T s value is lowered to 470 °C and below when cooled from a peak temperature of 1200 °C and beyond, with almost complete transformation to lath martensite. In HSLA-100 steel, the T s value for accicular ferrite is found to be 470 °C to 490 °C when cooled from a peak temperature of 1000 °C, but is lowered below 450 °C when cooled from 1200 °C and beyond, with correspondingly higher austenite grain sizes. The transformation kinetics appears to be relatively faster in the fine-grained austenite than in the coarse-grained austenite, where the niobium is in complete solid solution. A mixed microstructure consisting of accicular ferrite and lath martensite is observed for practically all HAZ treatments. The coarse-grained HAZ (CGHAZ) of HSLA-80 steel shows a higher volume fraction of lath martensite in the final microstructure and is harder than the CGHAZ of HSLA-100 steel.
Ocean tidal dissipation and its role in solar system satellite evolution
Chen, Erinna M.
The history of satellites in the Solar System is quite diverse. For example, satellites like Io and Enceladus exhibit active volcanism currently, while satellites like Ganymede and Tethys show signs of geologic activity in the deep past, but not at present. The energy dissipated by tides has been identified as a major heat source for satellites, but calculations for satellite tidal dissipation primarily focus on dissipation in a solid layer, such as the ice shell. An exciting discovery of the NASA spacecraft missions Galileo and Cassini is that global-scale, deep, liquid water oceans are present on many of the outer Solar System satellites. Tyler (2008) suggested that tidal dissipation due to flow in these oceans could potentially be a significant and previously neglected source of heat. However, a critical free parameter in Tyler's model is the effective turbulent viscosity in the ocean. The value of the effective viscosity is unconstrained and because the amount of tidal dissipation scales with this parameter, the amount of ocean tidal dissipation is also unconstrained. In order to address this uncertainty, we developed a numerical model that solves the shallow-water equations on a spherical shell and includes a nonlinear bottom friction parameterization for viscous dissipation. The bottom friction coefficient has a well-established value in the terrestrial literature; however, the nonlinearity of this term in the equations of motion make the model far more computationally expensive than a model that includes turbulent viscosity. Thus, we provide numerically-derived scalings that map the bottom friction coefficient and satellite parameters to an equivalent effective turbulent viscosity. Because tides depend on both the thermal structure of a satellite as well as characteristics of the satellite's orbit, models that couple thermal and orbital evolution are required to understand the history of a satellite. We use our numerically-derived scalings to adapt a coupled
Indian Academy of Sciences (India)
Ke Wu; Le Wang; Yi-Bo Yu; Zhi-Yi Huang; Pei Liang
2013-12-01
Heat dissipation enhancement of LED luminaries is of great significance to the large-scale application of LED. Luminaries-level structure improvement by the method of boring through-hole is adopted to intensify heat dissipation. Furthermore, the natural convection heat transfer process of LED luminaries is simulated by computational fluid dynamics (CFD) model before and after the structural modification. As shown by computational results, boring through-hole is beneficial to develop bottomto-top natural convection, eliminate local circumfluence, and finally form better flow pattern. Analysis based on field synergy principle shows that boring through-hole across LED luminaries improves the synergy between flow field and temperature field, and effectively decreases the thermal resistance of luminaries-level heat dissipation structure. Under the same computational conditions, by luminaries-level structure improvement the highest temperature of heat sink is decreased by about 8° C and the average heat transfer coefficient is increased by 45.8%.
Dissipation and fluctuation of the relative momentum in nucleus-nucleus collisions
International Nuclear Information System (INIS)
The dissipation of the relative momentum in nucleus-nucleus collisions is treated in terms of a Langevin equation with a fluctuating force. Equations of motion for first and second moments of the macroscopic variables are derived directly from the Langevin equation. The properties of the fluctuating force which results from random particle exchange are investigated in detail. Drift and diffusion coefficients are calculated microscopically and analytical expressions are given which can be used in any trajectory calculation. An important feature of the model is that the Einstein relation between dissipation and fluctuation turns out to be only a limiting case of a more general expression which included nonthermal fluctuations. By treating the two nuclei as intrinsically equilibrated but not in thermal equilibrium with respect to each other several important aspects of the dissipative behaviour, seen in heavy ion collisions with final energies above the Coloumb barrier, can be understood. (orig.)
Spectral Energy Transfer and Dissipation of Magnetic Energy from Fluid to Kinetic Scales
Bowers, K.; Li, H.
2007-01-01
We investigate the magnetic energy transfer from the fluid to kinetic scales and dissipation processes using three-dimensional fully kinetic particle-in-cell plasma simulations. The nonlinear evolution of a sheet pinch is studied where we show that it exhibits both fluid scale global relaxation and kinetic scale collisionless reconnection at multiple resonant surfaces. The interactions among collisionless tearing modes destroy the original flux surfaces and produce stochastic fields, along with generating sheets and filaments of intensified currents. In addition, the magnetic energy is transferred from the original shear length scale both to the large scales due to the global relaxation and to the smaller, kinetic scales for dissipation. The dissipation is dominated by the thermal or pressure effect in the generalized Ohm’s law, and electrons are preferentially accelerated.
Smoothed dissipative particle dynamics with angular momentum conservation
Energy Technology Data Exchange (ETDEWEB)
Müller, Kathrin, E-mail: k.mueller@fz-juelich.de; Fedosov, Dmitry A., E-mail: d.fedosov@fz-juelich.de; Gompper, Gerhard, E-mail: g.gompper@fz-juelich.de
2015-01-15
Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier–Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor–Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.
Draebing, Daniel; Krautblatter, Michael
2014-05-01
time, how snow cover controls the timing and the extent of active layer thawing and kinematic processes in permafrost affected rock walls. References: Draebing, D., M. Krautblatter, and R. Dikau (in rev.), Interaction of thermal and mechanical processes in steep permafrost rock walls: a conceptual approach, Geomorphology. Krautblatter, M., and D. Draebing (2013), Pseudo 3D - P-wave refraction seismic monitoring of permafrost in steep unstable bedrock, Journal of Geophysical Research: Earth Surface, 2012JF002638.
A Multi-Environment Thermal Control System With Freeze-Tolerant Radiator Project
National Aeronautics and Space Administration — Future space exploration missions require advanced thermal control systems (TCS) to dissipate heat from spacecraft, rovers, or habitats to external environments. We...
Rotational dissipation and the Miesowicz coefficients.
Simões, M; Yamaguti, K; Palangana, A J
2009-12-01
In this work, we will study the relative contribution of each of the two dissipative channels of the Eriksen, Leslie, and Parodi (ELP) approach to the observed values of the Miesowicz viscosity coefficients of the nematic liquid crystals. According to the fundamental equation of the liquid crystal's viscosity dissipative process, TS=-integral d3r(sigma)ijA(ij)+hxN , there are two channels by which the nematic viscous dissipation can occur: or it occurs by means of a shear flow configuration, where A(ij) is the characterizing term, or it occurs by means of a rotational configuration, where N is the characterizing term (these parameters will be defined in the paper). It will be also shown that this relative contribution can be measured by a simple relationship connecting the Miesowicz coefficients, which exhibits a quasitemperature independent behavior, suggesting that it is nearly constant through the entire domain of the nematic phase. PMID:20365179
Cascaded generation of coherent Raman dissipative solitons.
Kharenko, Denis S; Bednyakova, Anastasia E; Podivilov, Evgeniy V; Fedoruk, Mikhail P; Apolonski, Alexander; Babin, Sergey A
2016-01-01
The cascaded generation of a conventional dissipative soliton (at 1020 nm) together with Raman dissipative solitons of the first (1065 nm) and second (1115 nm) orders inside a common fiber laser cavity is demonstrated experimentally and numerically. With sinusoidal (soft) spectral filtering, the generated solitons are mutually coherent at a high degree and compressible down to 300 fs. Numerical simulation shows that an even higher degree of coherence and shorter pulses could be achieved with step-like (hard) spectral filtering. The approach can be extended toward a high-order coherent Raman dissipative soliton source offering numerous applications such as frequency comb generation, pulse synthesis, biomedical imaging, and the generation of a coherent mid-infrared supercontinuum. PMID:26696187
Energy Dissipation Control of Hysteretic Dampers
DEFF Research Database (Denmark)
Høgsberg, Jan Riess; Krenk, Steen
2006-01-01
The efficiency of a damper depends on the amount of energy dissipation during a typical cycle experienced by the damper. For viscous dampers this leads to substantial frequency dependence, and typically implies that optimal tuning of a passive viscous damper is valid only for a particular mode....... In contrast the energy dissipated by a hysteretic damper is independent of frequency, but depends on the amplitude and also contains a stiffness component. The present paper presents a procedure for predicting the magnitude of the closed hysteresis loops and thereby the energy dissipation, and a procedure...... for on-line tuning of the damper properties for random response. The approach is illustrated for the bilinear elasto-plastic damper, where the optimal relation between yield level and displacement amplitude is derived....
Intermittency of Energy Dissipation in Alfvenic Turbulence
Zhdankin, Vladimir; Chen, Christopher H K
2015-01-01
We investigate the intermittency of energy dissipation in Alfvenic turbulence by considering the statistics of the coarse-grained energy dissipation rate, using direct measurements from numerical simulations of magnetohydrodynamic turbulence and surrogate measurements from the solar wind. We compare the results to the predictions of the log-normal and log-Poisson random cascade models. We find that, to a very good approximation, the log-normal model describes the probability density function for the energy dissipation over a broad range of scales, but does not accurately describe the scaling exponents of the moments. The log-Poisson model better describes the scaling exponents of the moments, while the comparison with the probability density function is not straightforward.
Dissipative Effect in Long Baseline Neutrino Experiments
Oliveira, Roberto L N
2016-01-01
The propagation of neutrinos in long baselines experiments may be influenced by dissipation effects. Using Lindblad Master Equation we evolve neutrinos taking into account these dissipative effects. The MSW and the dissipative effects may change the probabilities behavior. In this work, we show and explain how the behavior of the probabilities can change due to the decoherence and relaxation effects acting individually with the MSW effect. A new exotic peak appears in this case and we show the difference between the decoherence and relaxation effects in the appearance of this peak. We also adapt the usual approximate expression for survival and appearance probabilities with all possible decoherence effects. We suppose the baseline of DUNE and show how each decoherence parameters change the probabilities analyzing the possible modification using numeric and analytic approach.
Bistability in a Driven-Dissipative Superfluid
Labouvie, Ralf; Santra, Bodhaditya; Heun, Simon; Ott, Herwig
2016-06-01
We experimentally study a driven-dissipative Josephson junction array, realized with a weakly interacting Bose-Einstein condensate residing in a one-dimensional optical lattice. Engineered losses on one site act as a local dissipative process, while tunneling from the neighboring sites constitutes the driving force. We characterize the emerging steady states of this atomtronic device. With increasing dissipation strength γ the system crosses from a superfluid state, characterized by a coherent Josephson current into the lossy site, to a resistive state, characterized by an incoherent hopping transport. For intermediate values of γ , the system exhibits bistability, where a superfluid and an incoherent branch coexist. We also study the relaxation dynamics towards the steady state, where we find a critical slowing down, indicating the presence of a nonequilibrium phase transition.
Fundamental plane: dark matter and dissipation contributions
Ribeiro, Andre L B
2010-01-01
Stellar and galactic systems are objects in dynamical equilibrium that are composed of ordinary baryonic matter hypothetically embedded in extended dominant dark matter halos. Our aim is to investigate the scaling relations and dissipational features of these objects over a wide range of their properties, taking the dynamical influence of the dark matter component into account. We study the physical properties of these self-gravitating systems using the two-component virial theorem in conjunction with data that embrace a wide range of astrophysical systems. We find that the scaling relations defined by the properties of these objects admit a dark-to-luminous density ratio parameter as a natural requirement in this framework. We also probe dissipational effects on the fundamental surface defined by the two-component virial theorem and discuss their relations with respect to the region devoid of objects in the data distribution. Our results indicate complementary contributions of dissipation and dark matter to ...
Constraints on dissipation in the deep interiors of Ganymede and Europa from tidal phase-lags
Hussmann, Hauke; Shoji, Daigo; Steinbrügge, Gregor; Stark, Alexander; Sohl, Frank
2016-08-01
Jupiter's satellites are subject to strong tidal forces which result in variations of the gravitational potential and deformations of the satellites' surfaces on the diurnal tidal cycle. Such variations are described by the Love numbers k_2 and h_2 for the tide-induced potential variation due to internal mass redistribution and the radial surface displacement, respectively. The phase-lags φ _{k_2} and φ _{h_2} of these complex numbers contain information about the rheological and dissipative states of the satellites. Starting from interior structure models and assuming a Maxwell rheology to compute the tidal deformation, we calculate the phase-lags in application to Ganymede and Europa. For both satellites we assume a decoupling of the outer ice-shell from the deep interior by a liquid subsurface water ocean. We show that, in this case, the phase-lag difference Δ φ = φ _{k_2}- φ _{h_2} can provide information on the rheological and thermal state of the deep interiors if the viscosities of the deeper layers are small. In case of Ganymede, phase-lag differences can reach values of a few degrees for high-pressure ice viscosities {indicate a highly dissipative state of the deep interior. In this case Δ φ is dominated by dissipation in the high-pressure ice layer rather than dissipation within the ice-I shell. These phase lags would be detectable from spacecraft in orbit around the satellite. For Europa Δ φ could reach values exceeding 20° and phase-lag measurements could help distinguish between (1) a hot dissipative silicate mantle which would in thermal equilibrium correspond to a very thin outer ice-I shell and (2) a cold deep interior implying that dissipation would mainly occur in a thick (several tens of km) outer ice-I shell. These measurements are highly relevant for ESA's Jupiter Icy Moons Explorer (JUICE) and NASA's Europa Multiple Flyby Mission, both targeted for the Jupiter system.
INTRACORPOREAL HEAT DISSIPATION FROM A RADIOISOTOPE-POWERED ARTIFICIAL HEART.
Huffman, Fred N.; Hagen, Kenneth G.; Whalen, Robert L.; Fuqua, John M.; Norman, John C.
1974-01-01
The feasibility of radioisotope-fueled circulatory support systems depends on the ability of the body to dissipate the reject heat from the power source driving the blood pump as well as to tolerate chronic intracorporeal radiation. Our studies have focused on the use of the circulating blood as a heat sink. Initial in vivo heat transfer studies utilized straight tube heat exchangers (electrically and radioisotope energized) to replace a segment of the descending aorta. More recent studies have used a left ventricular assist pump as a blood-cooled heat exchanger. This approach minimizes trauma, does not increase the area of prosthetic interface with the blood, and minimizes system volume. Heat rejected from the thermal engine (vapor or gas cycle) is transported from the nuclear power source in the abdomen to the pump in the thoracic cavity via hydraulic lines. Adjacent tissue is protected from the fuel capsule temperature (900 to 1200 degrees F) by vacuum foil insulation and polyurethane foam. The in vivo thermal management problems have been studied using a simulated thermal system (STS) which approximates the heat rejection and thermal transport mechanisms of the nuclear circulatory support systems under development by NHLI. Electric heaters simulate the reject heat from the thermal engines. These studies have been essential in establishing the location, suspension, surgical procedures, and postoperative care for implanting prototype nuclear heart assist systems in calves. The pump has a thermal impedance of 0.12 degrees C/watt. Analysis of the STS data in terms of an electrical analog model implies a heat transfer coefficient of 4.7 x 10(-3) watt/cm(2) degrees C in the abdomen compared to a value of 14.9 x 10(-3) watt/cm(2) degrees C from the heat exchanger plenum into the diaphragm.
Dissipative soliton protocols in semiconductor microcavities at finite temperatures
Karpov, D. V.; Savenko, I. G.; Flayac, H.; Rosanov, N. N.
2015-08-01
We consider exciton polaritons in a semiconductor microcavity with a saturable absorber in the growth direction of the heterostructure. This feature promotes additional nonlinear losses of the system with the emergence of bistability of the condensate particles number on the nonresonant (electrical or optical) excitation intensity. Furthermore, we demonstrate a new type of bright spatial dissipative exciton-polariton soliton which emerges in the equilibrium between the regions with different particle density. We develop protocols of soliton creation and destruction. The switch to a solitonlike behavior occurs if the cavity is exposed by a short strong laser pulse with certain energy and duration. We estimate the characteristic times of soliton switch on and off and the time of return to the initial cycle. In particular, we demonstrate surprising narrowing of the spatial profile of the soliton and its vanishing at certain temperature due to interaction of the system with the thermal bath of acoustic phonons. We also address the role of polariton-polariton interaction (Kerr-like nonlinearity) on formation of dissipative solitons and show that the soliton may exist both in its presence and its absence.
Dissipative phenomena in condensed matter some applications
Dattagupta, Sushanta
2004-01-01
From the field of nonequilibrium statistical physics, this graduate- and research-level volume treats the modeling and characterization of dissipative phenomena. A variety of examples from diverse disciplines like condensed matter physics, materials science, metallurgy, chemical physics etc. are discussed. Dattagupta employs the broad framework of stochastic processes and master equation techniques to obtain models for a wide range of experimentally relevant phenomena such as classical and quantum Brownian motion, spin dynamics, kinetics of phase ordering, relaxation in glasses, dissipative tunneling. It provides a pedagogical exposition of current research material and will be useful to experimentalists, computational physicists and theorists.
Dissipative fragmentation in a phase space approach
Energy Technology Data Exchange (ETDEWEB)
Adorno, A.; Di Toro, M.; Bonasera, A.; Gregoire, C.; Gulminelli, F.
Semi-classical approaches have evidenced the role of one and two-body dissipation in nucleus-nucleus collisions. On the other hand, a substantial energy dissipation and some angular momentum transfer have been observed at moderate energy where a fragmentation process is the dominant reaction mechanism. In order to analyse main features of these reactions, we developed a phenomenological model taking into account phase space constraints. The transition between deep inelastic collisions and abrasion-like fragmentation is described and a general agreement with available data is found.
Appendix to Power Dissipation in Division
DEFF Research Database (Denmark)
Liu, Wei; Nannarelli, Alberto
This document is an appendix to the paper: Wei Liu and Alberto Nannarelli, ”Power Dissipation in Division”, Proc. of 42nd Asilomar Conference on Signals, Systems, and Computers, October 2008. The purpose of the document is to provide the necessary information for the implementation of the archite......This document is an appendix to the paper: Wei Liu and Alberto Nannarelli, ”Power Dissipation in Division”, Proc. of 42nd Asilomar Conference on Signals, Systems, and Computers, October 2008. The purpose of the document is to provide the necessary information for the implementation...
Fluctuations and dissipations in stochastic energetic resonance
Institute of Scientific and Technical Information of China (English)
Xue Sheng-Hu; Lin Min; Meng Ying
2012-01-01
By analyzing the fluctuations and dissipations of a Brownian particle colliding with the molecules in a fluid,the work exchanged between the Brownian particle constrained in a bistable potential well and an external periodic force is investigated.Characters of the stochastic energetic resonance are found and studied at different intensities of fluctuations and dissipations.The microscopic mechanism of energy exchange between the Brownian particle and the external force is revealed.The method used in this study provides a novel way of controlling the stochastic energetic resonance.
Effective dissipation: breaking time-reversal symmetry
Brown, Aidan I
2016-01-01
At molecular scales, fluctuations play a significant role and prevent biomolecular processes from always proceeding in a preferred direction, raising the question of how limited amounts of free energy can be dissipated to obtain directed progress. We examine the system and process characteristics that efficiently break time-reversal symmetry at fixed energy loss; in particular for a simple model of a molecular machine, an intermediate energy barrier produces unusually high asymmetry for a given dissipation. Such insight into symmetry-breaking factors that produce particularly high time asymmetry suggests generalizations to a broader class of systems.
Complex Fluids in Energy Dissipating Systems
Directory of Open Access Journals (Sweden)
Francisco J. Galindo-Rosales
2016-07-01
Full Text Available The development of engineered systems for energy dissipation (or absorption during impacts or vibrations is an increasing need in our society, mainly for human protection applications, but also for ensuring the right performance of different sort of devices, facilities or installations. In the last decade, new energy dissipating composites based on the use of certain complex fluids have flourished, due to their non-linear relationship between stress and strain rate depending on the flow/field configuration. This manuscript intends to review the different approaches reported in the literature, analyses the fundamental physics behind them and assess their pros and cons from the perspective of their practical applications.
Extreme dissipation event due to plume collision in a turbulent convection cell
Schumacher, Jörg; Scheel, Janet D.
2016-10-01
An extreme dissipation event in the bulk of a closed three-dimensional turbulent convection cell is found to be correlated with a strong reduction of the large-scale circulation flow in the system that happens at the same time as a plume emission event from the bottom plate. The reduction in the large-scale circulation opens the possibility for a nearly frontal collision of down- and upwelling plumes and the generation of a high-amplitude thermal dissipation layer in the bulk. This collision is locally connected to a subsequent high-amplitude energy dissipation event in the form of a strong shear layer. Our analysis illustrates the impact of transitions in the large-scale structures on extreme events at the smallest scales of the turbulence, a direct link that is observed in a flow with boundary layers. We also show that detection of extreme dissipation events which determine the far-tail statistics of the dissipation fields in the bulk requires long-time integrations of the equations of motion over at least a hundred convective time units.
Extreme dissipation event due to plume collision in a turbulent convection cell
Schumacher, Joerg
2016-01-01
An extreme dissipation event in the bulk of a closed three-dimensional turbulent convection cell is found to be correlated with a strong reduction of the large-scale circulation flow in the system that happens at the same time as a plume emission event from the bottom plate. The reduction in the large-scale circulation opens the possibility for a nearly frontal collision of down- and upwelling plumes and the generation of a high-amplitude thermal dissipation layer in the bulk. This collision is locally connected to a subsequent high-amplitude energy dissipation event in the form of a strong shear layer. Our analysis illustrates the impact of transitions in the large-scale structures on extreme events at the smallest scales of the turbulence, a direct link that is observed in a flow with boundary layers. We also show that detection of extreme dissipation events which determine the far-tail statistics of the dissipation fields in the bulk requires long-time integrations of the equations of motion over at least ...
He, Zhiyong; Tao, Yadan; Zeng, Maomao; Zhang, Shuang; Tao, Guanjun; Qin, Fang; Chen, Jie
2016-06-01
The effects of high pressure homogenization processing (HPHP), thermal treatment (TT) and milk matrix (soy, skimmed and whole milk) on the phenolic bioaccessibility and the ABTS scavenging activity of apple, grape and orange juice (AJ, GJ and OJ) were investigated. HPHP and soy milk diminished AJ's total phenolic bioaccessibility 29.3%, 26.3%, respectively, whereas TT and bovine milk hardly affected it. HPHP had little effect on GJ's and OJ's total phenolic bioaccessibility, while TT enhanced them 27.3-33.9%, 19.0-29.2%, respectively, and milk matrix increased them 26.6-31.1%, 13.3-43.4%, respectively. Furthermore, TT (80 °C/30 min) and TT (90 °C/30 s) presented the similar influences on GJ's and OJ's phenolic bioaccessibility. Skimmed milk showed a better enhancing effect on OJ's total phenolic bioaccessibility than soy and whole milk, but had a similar effect on GJ's as whole milk. These results contribute to promoting the health benefits of fruit juices by optimizing the processing and formulas in the food industry. PMID:26830567
He, Zhiyong; Tao, Yadan; Zeng, Maomao; Zhang, Shuang; Tao, Guanjun; Qin, Fang; Chen, Jie
2016-06-01
The effects of high pressure homogenization processing (HPHP), thermal treatment (TT) and milk matrix (soy, skimmed and whole milk) on the phenolic bioaccessibility and the ABTS scavenging activity of apple, grape and orange juice (AJ, GJ and OJ) were investigated. HPHP and soy milk diminished AJ's total phenolic bioaccessibility 29.3%, 26.3%, respectively, whereas TT and bovine milk hardly affected it. HPHP had little effect on GJ's and OJ's total phenolic bioaccessibility, while TT enhanced them 27.3-33.9%, 19.0-29.2%, respectively, and milk matrix increased them 26.6-31.1%, 13.3-43.4%, respectively. Furthermore, TT (80 °C/30 min) and TT (90 °C/30 s) presented the similar influences on GJ's and OJ's phenolic bioaccessibility. Skimmed milk showed a better enhancing effect on OJ's total phenolic bioaccessibility than soy and whole milk, but had a similar effect on GJ's as whole milk. These results contribute to promoting the health benefits of fruit juices by optimizing the processing and formulas in the food industry.
Mayachiew, Pornpimon; Charunuch, Chulaluck; Devahastin, Sakamon
2015-12-01
Legumes contain protein, micronutrients, and bioactive compounds, which provide various health benefits. In this study, soybean or mung bean was mixed in rice flour to produce by extrusion instant functional legume-rice porridge powder. The effects of the type and percentage (10%, 20%, or 30%, w/w) of legumes on the expansion ratio of the extrudates were first evaluated. Amino acid composition, color, and selected physicochemical (bulk density, water absorption index, and water solubility index), thermal (onset temperature, peak temperature, and transition enthalpy), and pasting (peak viscosity, trough viscosity, and final viscosity) properties of the powder were determined. The crystalline structure and formation of amylose-lipid complexes and the total phenolics content (TPC) and antioxidant activity of the powder were also measured. Soybean-blended porridge powder exhibited higher TPC, 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, ferric reducing antioxidant power, amino acid, and fat contents than the mung bean-blended porridge powder. Incorporating either legume affected the product properties by decreasing the lightness and bulk density, while increasing the greenness and yellowness and the peak temperature and transition enthalpy. Expansion capacity of the extrudates increased with percentage of mung bean in the mixture but decreased as the percentage of soybean increased. Amylose-lipid complexes formation was confirmed by X-ray diffraction analysis results. Addition of soybean or mung bean resulted in significant pasting property changes of the porridge powder.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The entransy dissipation extremum principle provides new warranty and criterion for optimization of heat transfer.For two cases(body with heat generation and body heated externally)of a solid conducting wall with an open cavity,a dimensionless equivalent thermal resistance based on entransy dissipation definition was taken as the optimization objective to optimize the model constructal ge- ometry.Numerical results validated the necessity and feasibility of the presented method.Comparisons of the numerical results based on minimization of dimensionless maximum thermal resistance and minimization of dimensionless equivalent thermal resistance,respectively,showed that there was no obvious difference between the two results when the volume fractionΦoccupied by cavity was small, but the difference between the two results increased with the increases ofΦand the body aspect ratio H/L for any model.The optimal cavities for bodies heated externally were more slender than those for bodies with heat generation.Heat origin had obvious effect on the global performance of heat transfer. The entransy dissipation of body heated externally increased 2―3 times than that of body with heat generation,indicating that the global performance of heat transfer weakened.The method presented herein provides some guidelines for some relevant thermal design problems.
Institute of Scientific and Technical Information of China (English)
Liu Shi-Xiong; Liu Jin-Song; Zhang Hui-Lan; Zhang Guang-Yong; Wang Cheng
2007-01-01
In an open-circuit dissipative photovoltaic (PV) crystal, by considering the diffusion effect, the deflection of bright dissipative photovoltaic (DPV) solitons has been investigated by employing numerical technique and perturbational procedure. The relevant results show that the centre of the optical beam moves along a parabolic trajectory, while the central spatial-frequency component shifts linearly with the propagation distance; furthermore, both the spatial deflection and the angular derivation are associated with the photovoltaic field. Such DPV solitons have a fixed deflection degree completely determined by the parameters of the dissipative system. The small bending cannot affect the formation of the DPV soliton via two-wave mixing.
K-12 Teacher Understanding of Energy Conservation: Conceptual Metaphor, Dissipation, and Degradation
Daane, Abigail R.
In K-12 educational settings, conservation of energy is typically presented in two ways: the conservation of energy principle (energy is neither created nor destroyed) and the sociopolitical need to conserve energy (we guard against energy being used up). These two meanings of conservation typically remain disconnected from each other and can appear contradictory, even after instruction. In an effort to support teachers in building robust understandings of energy from their existing knowledge, I designed a study to investigate the productive ideas in K-12 teachers' conversations about energy. A micro-analysis of discourse, gestures, and artifacts of professional development courses revealed teachers' productive ideas about three aspects of energy: conceptual metaphor, dissipation and degradation. In learning about energy, K-12 teachers come to use conceptual metaphors in their own language and value attending to students' metaphorical language as a means of formative assessment. Teachers' conversations about dissipation suggest that apparent difficulties with energy conservation may have their roots in a strong association between forms of energy (thermal) and their perceptible indicators (warmth). Teachers address this challenge by employing an exaggeration strategy to locate the dissipated thermal energy, making the energy indicator perceptible. Finally, teachers' unprompted statements about sociopolitical aspects of energy are related to both statements from the NGSS and aspects of energy degradation. I conclude that energy conservation can be better taught and learned in K-12 Education by: 1) understanding and applying conceptual metaphors about energy in K-12 settings, 2) using prior experiences to better understand dissipative energy processes involving imperceptible thermal energy, thereby understanding how energy conservation applies in all situations, and 3) connecting productive ideas about sociopolitical aspects of energy to canonical physics. Keywords
Entanglement dynamics of a pure bipartite system in dissipative environments
Energy Technology Data Exchange (ETDEWEB)
Tahira, Rabia; Ikram, Manzoor; Azim, Tasnim; Suhail Zubairy, M [Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)
2008-10-28
We investigate the phenomenon of sudden death of entanglement in a bipartite system subjected to dissipative environments with arbitrary initial pure entangled state between two atoms. We find that in a vacuum reservoir the presence of the state where both atoms are in excited states is a necessary condition for the sudden death of entanglement. Otherwise entanglement remains for an infinite time and decays asymptotically with the decay of individual qubits. For pure 2-qubit entangled states in a thermal environment, we observe that the sudden death of entanglement always happens. The sudden death time of the entangled states is related to the temperature of the reservoir and the initial preparation of the entangled states.
Modeling nanoscale hydrodynamics by smoothed dissipative particle dynamics
Lei, Huan; Mundy, Christopher J.; Schenter, Gregory K.; Voulgarakis, Nikolaos K.
2015-05-01
Thermal fluctuation and hydrophobicity are two hallmarks of fluid hydrodynamics on the nano-scale. It is a challenge to consistently couple the small length and time scale phenomena associated with molecular interaction with larger scale phenomena. The development of this consistency is the essence of mesoscale science. In this study, we use a nanoscale fluid model based on smoothed dissipative particle dynamics that accounts for the phenomena associated with density fluctuations and hydrophobicity. We show consistency in the fluctuation spectrum across scales. In doing so, it is necessary to account for finite fluid particle size. Furthermore, we demonstrate that the present model can capture the void probability and solvation free energy of nonpolar hard particles of different sizes. The present fluid model is well suited for an understanding of emergent phenomena in nano-scale fluid systems.
Modeling nanoscale hydrodynamics by smoothed dissipative particle dynamics
Energy Technology Data Exchange (ETDEWEB)
Lei, Huan; Mundy, Christopher J.; Schenter, Gregory K.; Voulgarakis, Nikolaos
2015-05-21
Thermal fluctuation and hydrophobicity are two hallmarks of fluid hydrodynamics on the nano-scale. It is a challenge to consistently couple the small length and time scale phenomena associated with molecular interaction with larger scale phenomena. The development of this consistency is the essence of mesoscale science. In this study, we develop a nanoscale fluid model based on smoothed dissipative particle dynamics that accounts for the phenomena of associated with density fluctuations and hydrophobicity. We show consistency in the fluctuation spectrum across scales. In doing so, it is necessary to account for finite fluid particle size. Furthermore, we demonstrate that the present model can capture of the void probability and solvation free energy of apolar particles of different sizes. The present fluid model is well suited for a understanding emergent phenomena in nano-scale fluid systems.
Relativistic dissipative hydrodynamics with spontaneous symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Pujol, C.; Davesne, D. [IPN - Lyon, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France)
2002-07-01
In this paper we consider dissipative hydrodynamic equations for systems with continuous broken symmetries. We first present the case of superfluidity, in which the symmetry U(1) is broken and then generalize to the chiral symmetry SU(2){sub L} x SU(2){sub R}. New transport coefficients are introduced and the consequences of their existence are discussed. (authors)
Pederson Current Dissipation In Emerging Active Regions
Leake, James E.; Linton, M. G.
2011-05-01
Pederson current dissipation in emerging active regions. Certain regions of the solar atmosphere, such as the photosphere and chromosphere, as well as prominences, contain a significant amount of neutral atoms, and a complete description of the plasma requires including the effects of partial ionization. In the chromosphere the dissipation of Pederson currents is important for the evolution of emerging magnetic fields. Due to the relatively high number density in the chromosphere, the ion-neutral collision time-scale is much smaller than timescales associated with flux emergence. Hence we use a single-fluid approach to model the partially ionized plasma. Looking at both the emergence of large-scale sub-surface structures, and the emergence and reconnection of undulatory fields, we investigate the effect of Pederson current dissipation on the state of the emerging field, on magnetic reconnection and on dissipative heating of the atmosphere. Specifically we examine the effect of motions across fieldlines in the partially ionized regions, and how this can increase the free energy supplied to the corona by flux emergence. We also look at reconnection associated with flux emergence in the partially ionized atmosphere, and how this can account for observed small-scale brightenings (Ellerman Bombs).
LANGEVIN APPROACH TO NUCLEAR DISSIPATIVE DYNAMICS
Abe, Y.; Grégoire, C.; Delagrange, H.
1986-01-01
Langevin approach is proposed as an intuitive phenomenological framework to describe nuclear dissipative phenomena such as heavy ion reactions and fission decay. We present a method to integrate Langevin equation directly with the computer-simulated langevin force. Examples are given for a free motion of Brownian particle and for nuclear fission as a diffusion over a barrier.
Dissipative particle dynamics for interacting systems
Pagonabarraga, I.; Frenkel, D.
2001-01-01
We introduce a dissipative particle dynamics scheme for the dynamics of nonideal fluids. Given a free-energy density that determines the thermodynamics of the system, we derive consistent conservative forces. The use of these effective, density dependent forces reduces the local structure as compare
Dissipative preparation of entanglement in optical cavities
DEFF Research Database (Denmark)
Kastoryano, Michael James; Reiter, Florentin; Sørensen, Anders Søndberg
2011-01-01
We propose a novel scheme for the preparation of a maximally entangled state of two atoms in an optical cavity. Starting from an arbitrary initial state, a singlet state is prepared as the unique fixed point of a dissipative quantum dynamical process. In our scheme, cavity decay is no longer...
Relativistic dissipative hydrodynamics with spontaneous symmetry breaking
Pujol, C
2003-01-01
In this paper we consider dissipative hydrodynamic equations for systems with continuous broken symmetries. We first present the case of superfluidity, in which the symmetry U(1) is broken and then generalize to the chiral symmetry $SU(2)_L \\times SU(2)_R$. New transport coefficients are introduced and the consequences of their existence are discussed.
Thermal Reversible Breakdown and Resistivity Switching in Hafnium Dioxide
Directory of Open Access Journals (Sweden)
N. Raghavan
2012-03-01
Full Text Available We present a model of thermal reversible breakdown via conductive filaments (CFs in hafnium dioxide (HfO2. These CFs appear as a result of electrical pretreatment of a metal/HfO2/metal (semiconductor nanostructure (MIM(S. The model is based on an assumption that the thermal reversible breakdown of a CF is due to of Joule heating displaying an exponential dependence of conductivity on temperature. The corresponding current-voltage characteristic and temperature of a CF in its middle and at the interface with an electrode are calculated taking into account the heat conduction equation and boundary conditions with heat dissipation via electrodes. It is found that the current-voltage characteristic of a CF has three specific regions. The initial and final regions have turned out to be linear with respect to the current and display different slopes, while the middle region is characterized by both the S-shaped and ultralinear dependences which are affected by the ambient temperature and nanostructure parameters. The switching potential from the high resistivity state (HRS to the low resistivity state (LRS was shown to decrease with the ambient temperature and with worsening of heat dissipation conditions. We present a model of thermal reversible breakdown via conductive filaments (CFs in hafnium dioxide (HfO2. These CFs appear as a result of electrical pretreatment of a metal/HfO2/metal (semiconductor nanostructure (MIM(S. The model is based on an assumption that the thermal reversible breakdown of a CF is due to of Joule heating displaying an exponential dependence of conductivity on temperature. The corresponding current-voltage characteristic and temperature of a CF in its middle and at the interface with an electrode are calculated taking into account the heat conduction equation and boundary conditions with heat dissipation via electrodes. It is found that the current-voltage characteristic of a CF has three specific regions. The initial and
Dynamics of dissipative systems and computational physics
International Nuclear Information System (INIS)
During the first year of research activity in the frame of this project there have been investigated two main topics: I. Dynamics of systems of fermions in complex dissipative media; II. Solitons with topologic charge in dissipative systems. An essential problem of the quantum information systems is the controllability and observability of the quantum states, generally described by Lindblad's master equation with phenomenological coefficients. In its usual form, this equation describes a decay of the mean-values, but not necessarily the expected decaying transitions. The basic and very difficult problem of a dissipative quantum theory is to project the evolution of the total system (the system of interest + the environment) on the space of the system of interest. In this case, one obtains a quantum master equation where the system evolution is described by two terms: 1) a Hamiltonian term for the processes with energy conservation, and 2) a non-Hamiltonian term with coefficients depending on the dissipative coupling. That means that a master equation is based on some approximations enabling the replacement of the operators of the dissipative environment with average value coefficients. It is often assumed that the evolution operators of the dissipative system define a semigroup, not a group as in the case of an isolated system. In this framework, Lindblad obtained a quantum master equation in agreement with all the quantum-mechanical principles. However, the Lindblad master equation was unable to secure a correct description of the decaying states. To do that, one has to take into account the transition operators between the system eigenstates with appropriate coefficients. Within this investigation, we have obtained an equation obeying to this requirement, giving the ρ(t) time derivative in terms of creation-annihilation operators of the single-particle states |i>, and λij, representing the dissipative coefficients, the microscopic expressions of which are given
Mai-Duy, N.; Phan-Thien, N.; Khoo, B. C.
2015-04-01
In the Dissipative Particle Dynamics (DPD) simulation of suspension, the fluid (solvent) and colloidal particles are replaced by a set of DPD particles and therefore their relative sizes (as measured by their exclusion zones) can affect the maximal packing fraction of the colloidal particles. In this study, we investigate roles of the conservative, dissipative and random forces in this relative size ratio (colloidal/solvent). We propose a mechanism of adjusting the DPD parameters to properly model the solvent phase (the solvent here is supposed to have the same isothermal compressibility to that of water).
Mesoscopic simulation of a thinning liquid bridge using the dissipative particle dynamics method
Mo, Chao-jie; Yang, Li-jun; Zhao, Fei; Cui, Kun-da
2015-08-01
In this research, the dissipative particle dynamics method was used to investigate the problem of thinning and breakup in a liquid bridge. It was found that both the inertial-force-dominated thinning process and the thermal-fluctuation-dominated thinning process can be reproduced with the dissipative particle dynamics (DPD) method by varying the simulation parameters. A highly suspect viscous thinning regime was also found, but the conclusion is not irrefutable because of the complication of the shear viscosity of DPD fluid. We show in this article that the DPD method can serve as a good candidate to elucidate crossover problem in liquid bridge thinning from being hydrodynamics dominated to being thermal fluctuation dominated.
Energy Dissipation in Magnetohydrodynamic Turbulence: Coherent Structures or "Nanoflares"?
Zhdankin, Vladimir; Perez, Jean Carlos; Tobias, Steven M
2014-01-01
We investigate the intermittency of energy dissipation in magnetohydrodynamic (MHD) turbulence by identifying dissipative structures and measuring their characteristic scales. We find that the probability distribution of energy dissipation rates exhibits a power law tail with index very close to the critical value of -2.0, which indicates that structures of all intensities contribute equally to energy dissipation. We find that energy dissipation is uniformly spread among coherent structures with lengths and widths in the inertial range. At the same time, these structures have thicknesses deep within the dissipative regime. As the Reynolds number is increased, structures become thinner and more numerous, while the energy dissipation continues to occur mainly in large-scale coherent structures. This implies that in the limit of high Reynolds number, energy dissipation occurs in thin, tightly packed current sheets which nevertheless span a continuum of scales up to the system size, exhibiting features of both co...
Institute of Scientific and Technical Information of China (English)
张卫国; 刘强; 李正明; 李想
2014-01-01
This article studies bounded traveling wave solutions of variant Boussinesq equa-tion with a dissipation term and dissipation effect on them. Firstly, we make qualitative analysis to the bounded traveling wave solutions for the above equation by the theory and method of planar dynamical systems, and obtain their existent conditions, number, and gen-eral shape. Secondly, we investigate the dissipation effect on the shape evolution of bounded traveling wave solutions. We find out a critical value r* which can characterize the scale of dissipation effect, and prove that the bounded traveling wave solutions appear as kink profile waves if |r|≥r*; while they appear as damped oscillatory waves if |r|
Indian Academy of Sciences (India)
Ibrahim A Abbas
2011-06-01
The theory of thermoelasticity with energy dissipation is employed to study plane waves in a ﬁbre-reinforced anisotropic thermoelastic half-space. We apply a thermal shock on the surface of the half-space which is taken to be traction free. The problem is solved numerically using a ﬁnite element method. Moreover, the numerical solutions of the non-dimensional governing partial differential equations of the problem are shown graphically. Comparisons are made with the results predicted by Green–Naghdi theory of the two types (GNII without energy dissipation) and (GNIII with energy dissipation). We found that the reinforcement has great effect on the distribution of ﬁeld quantities. Results carried out in this paper can be used to design various ﬁbre-reinforced anisotropic thermoelastic elements under thermal load to meet special engineering requirements.
A Dissipative-Particle-Dynamics Model for Simulating Dynamics of Charged Colloid
Zhou, Jiajia; Schmid, Friederike
2013-01-01
A mesoscopic colloid model is developed in which a spherical colloid is represented by many interacting sites on its surface. The hydrodynamic interactions with thermal fluctuations are taken accounts in full using Dissipative Particle Dynamics, and the electrostatic interactions are simulated using Particle-Particle-Particle Mesh method. This new model is applied to investigate the electrophoretic mobility of a charged colloid under an external electric field, and the influence of salt conce...
Phase-slip induced dissipation in an atomic Bose-Hubbard system
McKay, D; White, M.; Pasienski, M.; DeMarco, B.
2007-01-01
Phase slips play a primary role in dissipation across a wide spectrum of bosonic systems, from determining the critical velocity of superfluid helium to generating resistance in thin superconducting wires. This subject has also inspired much technological interest, largely motivated by applications involving nanoscale superconducting circuit elements, e.g., standards based on quantum phase-slip junctions. While phase slips caused by thermal fluctuations at high temperatures are well understoo...
Dissipative effects in fission investigated with proton-on-lead reactions
Directory of Open Access Journals (Sweden)
Rodríguez-Sánchez J. L.
2016-01-01
Full Text Available The complete kinematic measurement of the two fission fragments permitted us to investigate dissipative effects at large deformations, between the saddle-point and the corresponding scission configurations. Up to now, this kind of study has only been performed with fusionfission reactions using a limited number of observables, such as the mass distribution of the fission fragments or the neutron multiplicities. However, the large angular momenta gained by the compound nucleus could affect the conclusions drawn from such experiments. In this work, the use of spallation reactions, where the fissioning systems are produced with low angular momentum, small deformations and high excitation energies, favors the study of dissipation, and allowed us to define new observables, such as postscission neutron multiplicities and the neutron excess of the final fission fragments as a function of the atomic number of the fissioning system. These new observables are used to investigate the dissipation at large deformations.
Aunai, Nicolas; Black, Carrie; Evans, Rebekah; Kuznetsova, Maria
2013-01-01
Numerical studies implementing different versions of the collisionless Ohm's law have shown a reconnection rate insensitive to the nature of the non-ideal mechanism occuring at the X line, as soon as the Hall effect is operating. Consequently, the dissipation mechanism occurring in the vicinity of the reconnection site in collisionless systems is usually thought not to have a dynamical role beyond the violation of the frozen-in condition. The interpretation of recent studies have however led to the opposite conclusion that the electron scale dissipative processes play an important dynamical role in preventing an elongation of the electron layer from throttling the reconnection rate. This work re-visits this topic with a new approach. Instead of focusing on the extensively studied symmetric configuration, we aim to investigate whether the macroscopic properties of collisionless reconnection are affected by the dissipation physics in asymmetric configurations, for which the effect of the Hall physics is substan...
DISSIPATION AND ENVIRONMENTAL RISK OF FIPRONIL ON AQUATIC ENVIRONMENT
Directory of Open Access Journals (Sweden)
JOAQUIM G. MACHADO-NETO
2013-06-01
Full Text Available Pesticides have been used in agriculture to avoid productivity losses caused by various organisms. However, the indiscriminate use of these chemicals has resulted in negative impacts on the environment, such as residues in soil, water, air, plants and animals. Fipronil is a phenylpyrazole insecticide widely used in agricultural management to control pests of sugar cane in Brazil, and it can be leached into aquatic ecosystems. The present study aimed to evaluate the environmental risk of toxic concentrations and dissipation of fipronil to Poecilia reticulata, based on the 96-h median lethal concentration (LC50 value estimated at 0.08 ± 0.01 mg/L without sediment and 0.09 ± 0.01 mg/L with sediment of fipronil in the aquatic environment. These values of fipronil were classified as extremely toxic to P. reticulata in both cases, which showed high environmental risk of poisoning to a shallow film of water of 1 ha and 0.30 m deep, with and without sediment. On the other hand, in bodies of water 1 ha and 2.0 m deep, it was of moderate toxicity. Dissipation of fipronil in the water was not affected by temperature, sediment or photoperiod. The minimum time to which fipronil caused 50% acute mortality (0.08 mg/L after dilution of 0.75 mg/L was 242 days; the withdrawal period, after which no mortality occurs (0.025 mg/L, was 263 days.
Dissipation of glyphosate from grapevine soils in Sonora, Mexico
Directory of Open Access Journals (Sweden)
Norma J. Salazar López
2016-10-01
Full Text Available Grapevine is one of the important crops in Sonora, due to revenue generation from its export to foreign countries. Among the most widely used herbicides for this crop is glyphosate, which is considered moderately toxic and persistent. The present research evaluates the dissipation of glyphosate in grapevine planted soil at three depths (5, 30 and 60 cm. Sampling was carried out before glyphosate application, and 5, 10, 18, 27, and 65 days after. Glyphosate was extracted from soil samples using ammonium hydroxide. The derivate extracts were partitioned with dichloromethane and analyzed using gas chromatography with pulsed flame photometric detector (PFPD. The results showed that average glyphosate residues are significantly greater at 5 cm (0.09 mg kg-1 than the other depths (30 and 60 cm, having a difference of 0.078 mg kg-1 between them (P < 0.03. Glyphosate concentration time profiles were similar; it reached maximum soil concentration in a range of 10 to 18 days after application. The half-life of glyphosate in soil has an average of 39 days at all depths. Our data suggests that the release in soil of glyphosate applied to weeds delays its transference to soil by 14 days, and extends residue half life to 55 days after application. These results could be the basis for further research, including more environmental parameters that could affect the dissipation or degradation process in soil.
Experimental Study of Effect of Air Duct Structures on Heat Dissipation of Heating-Only Fan Coil
Institute of Scientific and Technical Information of China (English)
WU Xiao-zhou; ZHAO Jia-ning
2009-01-01
Heating-only fan coil(HFC) is one of the suited end users.which is not only compact but also highly efficient.And the major factors affecting the heat dissipation performance of HFC include leakage through coil bypass,distance between fan and coil,fan structure and air inlet type.Under natural air convection or forced,experimental studies were made on the effects of these factors upon the heat dissipation performance of HFC.The results show that:1)After reducing the leakage through coil bypass,the heat dissipation of HFC in-creases 16.9%under natural convection,and increases 8.3%under forced convection.2)After the distance be-tween fan and coil be raised from 23.2cm to 41.7cm.the heat dissipation of HFC decreases 21.3%under natu-ral convection,but increasesl2.8%under forced convection.3)After changing the fan structure,the heat dissi-pation of HFC increases 41.8%under natural convection.and the heat dissipation per motor power increases 96.1%under forced convection.4)The heat dissipations of HFC with round pass,slit and strip type of air inlet are different,whose proportion is about 100%,110%,136%under natural convection,and 100%,105%,116%under forced convection.
Estimating Half-Lives for Pesticide Dissipation from Plants
DEFF Research Database (Denmark)
Fantke, Peter; Gillespie, Brenda W.; Juraske, Ronnie;
2014-01-01
dissipation data with reported average air temperatures, we estimated a reaction activation energy of 14.25 kJ/mol and a temperature coefficient Q10 of 1.22 to correct dissipation from plants for the influence of temperature. We calculated a set of dissipation half-lives for 333 substances applied at 20 °C...
Institute of Scientific and Technical Information of China (English)
赵秀华; 赵平; 周娟; 张振振; 孙振伟; 钟文超
2015-01-01
In order to evaluate the applicability of TDP (Thermal dissipation probe) method used in transpiration measure of bamboo, the Granier empirical formula was verified and coefficients were revised by combining water-injection induced hydraulic pressure and sap flow changing device together with whole-plant container weighing menthods. In addition, the structure of vascular bundle in 5 bamboo species, includingPhyllostachys edulis,Bambusa chungii,B. textilis,Arundinaria amabilisandB. vulgariswas observed. The results showed that the distribution of vascular bundles in culms were uneven. The development of vascular bundles become mature gradually from outside to inside of clum, and the transporting water capability also become strong. The sap lfow density (Fd) andK value showed a power function relation withR2>0.83. It suggested that TDP method was an applicable technique for evaluating sap lfow density in bamboo species. Furthermore, the equation coefifcients were revised by using whole-plant container weighing method and new sap flow formula for every bamboo species were contained. The coefifcients in new sap lfow formula were different from those in Grnaier empirical formula especially α values. The daily transpiration had significant difference calculated by new equation and Granier empirical formula, especially the peak period (at noon) of sap flow in one day. Therefore, if the TDP method was carefully veriifed and the coefifcients in Granier empirical formula were revised, the TDP method could be an applicable technique for assessing water use in bamboo species.%为评价热消散法在竹子蒸腾耗水测定中的适用性，利用室内离体竹段注水变压法结合野外整株容器称重法对Granier公式进行了验证和系数校正，同时观察了5种竹子(毛竹Phyllostachys edulis、粉单竹Bambusa chungii、青皮竹B. textilis、茶秆竹Arundinaria amabilis、龙头竹B. vulgaris)的茎秆维管束结构。结果表明，茎秆维管束分
International Nuclear Information System (INIS)
Thermal habitats in effluent cooling waters from production nuclear reactors at the Savannah River Plant are unlike natural thermal habitats in that reactor operations are periodically halted, exposing the organisms growing in these thermal habitats to ambient temperatures for unpredictable lengths of time. Rates of primary production, glucose heterotrophy, and the composition of algal-bacterial mat communities growing along a thermal gradient from about 50 to 350C during periods of reactor operation were studied. Cyanobacteria were the only photoautotrophs in mat communities above 400C while cyanobacteria and eucaryotic algae comprised the photoautotrophic component of mat communities below 400C. The heterotrophic component of these communities above 400C was made up of stenothermic and eurythermic thermophilic bacteria while both eurythermic thermophiles and mesophilic bacteria were found in communities below 400C. Net CO2-fixation rates during thermal conditions dropped after initial exposure to ambient temperatures. After prolonged exposure of the thermal communities to ambient temperatures, adaptation and colonization by mesophilic algae occurred. Rates of glucose utilization under varying degrees of thermal influence suggested that the heterotrophic component may not have been optimally adapted to thermal conditions. During periods of changing thermal conditions, an increase in the percentage extracellular release of photosynthetically fixed 14CO2 by cyanobacteria and algae and an increase in the percentage of glucose mineralized (respired) by the heterotrophic component of the mat communities was observed. Results of temperature shift experiments indicated that the short-term response of the photoautotrophic component of these communities to thermal stress was an increase in the percentage of photosynthate released extracellularly
Mode-locking via dissipative Faraday instability.
Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K
2016-01-01
Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering. PMID:27503708
Fluctuations, dissipation and the dynamical Casimir effect
Dalvit, Diego A R; Mazzitelli, Francisco Diego
2010-01-01
Vacuum fluctuations provide a fundamental source of dissipation for systems coupled to quantum fields by radiation pressure. In the dynamical Casimir effect, accelerating neutral bodies in free space give rise to the emission of real photons while experiencing a damping force which plays the role of a radiation reaction force. Analog models where non-stationary conditions for the electromagnetic field simulate the presence of moving plates are currently under experimental investigation. A dissipative force might also appear in the case of uniform relative motion between two bodies, thus leading to a new kind of friction mechanism without mechanical contact. In this paper, we review recent advances on the dynamical Casimir and non-contact friction effects, highlighting their common physical origin.
Mode-locking via dissipative Faraday instability
Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.
2016-08-01
Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system--spectrally dependent losses--achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.
Effective dynamics of strongly dissipative Rydberg gases
Marcuzzi, M; Olmos, B; Lesanovsky, I
2014-01-01
We investigate the evolution of interacting Rydberg gases in the limit of strong noise and dissipation. Starting from a description in terms of a Markovian quantum master equation we derive effective equations of motion that govern the dynamics on a "coarse-grained" timescale where fast dissipative degrees of freedom have been adiabatically eliminated. Specifically, we consider two scenarios which are of relevance for current theoretical and experimental studies --- Rydberg atoms in a two-level (spin) approximation subject to strong dephasing noise as well as Rydberg atoms under so-called electromagnetically induced transparency (EIT) conditions and fast radiative decay. In the former case we find that the effective dynamics is described by classical rate equations up to second order in an appropriate perturbative expansion. This drastically reduces the computational complexity of numerical simulations in comparison to the full quantum master equation. When accounting for the fourth order correction in this e...
Dissipative self-assembly of vesicular nanoreactors.
Maiti, Subhabrata; Fortunati, Ilaria; Ferrante, Camilla; Scrimin, Paolo; Prins, Leonard J
2016-07-01
Dissipative self-assembly is exploited by nature to control important biological functions, such as cell division, motility and signal transduction. The ability to construct synthetic supramolecular assemblies that require the continuous consumption of energy to remain in the functional state is an essential premise for the design of synthetic systems with lifelike properties. Here, we show a new strategy for the dissipative self-assembly of functional supramolecular structures with high structural complexity. It relies on the transient stabilization of vesicles through noncovalent interactions between the surfactants and adenosine triphosphate (ATP), which acts as the chemical fuel. It is shown that the lifetime of the vesicles can be regulated by controlling the hydrolysis rate of ATP. The vesicles sustain a chemical reaction but only as long as chemical fuel is present to keep the system in the out-of-equilibrium state. The lifetime of the vesicles determines the amount of reaction product produced by the system. PMID:27325101
Metriplectic Framework for Dissipative Magneto-Hydrodynamics
Materassi, Massimo
2011-01-01
The metriplectic framework, which permits to formulate an algebraic structure for dissipative systems, is applied to visco-resistive Magneto-Hydrodynamics (MHD), adapting what had already been done for non-ideal Hydrodynamics (HD). The result is obtained by extending the HD symmetric bracket and free energy to include magnetic field dynamics and resistive dissipation. The correct equations of motion are obtained once one of the Casimirs of the Poisson bracket for ideal MHD is identified with the total thermodynamical entropy of the plasma. The metriplectic framework of MHD is shown to be invariant under the Galileo Group. The metriplectic structure also permits to obtain the asymptotic equilibria toward which the dynamics of the system evolves. This scheme is finally adapted to the two-dimensional incompressible resistive MHD, that is of major use in many applications.
Blast Dynamics in a Dissipative Gas.
Barbier, M; Villamaina, D; Trizac, E
2015-11-20
The blast caused by an intense explosion has been extensively studied in conservative fluids, where the Taylor-von Neumann-Sedov hydrodynamic solution is a prototypical example of self-similarity driven by conservation laws. In dissipative media, however, energy conservation is violated, yet a distinctive self-similar solution appears. It hinges on the decoupling of random and coherent motion permitted by a broad class of dissipative mechanisms. This enforces a peculiar layered structure in the shock, for which we derive the full hydrodynamic solution, validated by a microscopic approach based on molecular dynamics simulations. We predict and evidence a succession of temporal regimes, as well as a long-time corrugation instability, also self-similar, which disrupts the blast boundary. These generic results may apply from astrophysical systems to granular gases, and invite further cross-fertilization between microscopic and hydrodynamic approaches of shock waves. PMID:26636851
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...
Finite dissipation and intermittency in magnetohydrodynamics
Mininni, P D
2009-01-01
We present an analysis of data stemming from numerical simulations of decaying magnetohydrodynamic (MHD) turbulence up to grid resolution of 1536^3 points and up to Taylor Reynolds number of 1200. The initial conditions are such that the initial velocity and magnetic fields are helical and in equipartition, while their correlation is negligible. Analyzing the data at the peak of dissipation, we show that the dissipation in MHD seems to asymptote to a constant as the Reynolds number increases, thereby strengthening the possibility of fast reconnection events in the solar environment for very large Reynolds numbers. Furthermore, intermittency of MHD flows, as determined by the spectrum of anomalous exponents of structure functions of the velocity and the magnetic field, is stronger than for fluids, confirming earlier results; however, we also find that there is a measurable difference between the exponents of the velocity and those of the magnetic field, as observed recently in the solar wind. Finally, we discu...
Dissipative or Conservative cosmology with dark energy ?
Szydlowski, M; Hrycyna, Orest; Szydlowski, Marek
2006-01-01
All evolutional paths for all admissible initial conditions of FRW cosmological models with dissipative dust fluid (described by dark matter, baryonic matter and dark energy) are analysed using dynamical system approach. With that approach, one is able to see how generic the class of solutions leading to the desired property -- acceleration -- is. The theory of dynamical systems also offers a possibility of investigating all possible solutions and their stability with tools of Newtonian mechanics of a particle moving in 1D potential which is parametrised by the cosmological scale factor. We demonstrate that flat cosmology with bulk viscosity can be treated as a conservative system with a potential function of the Chaplygin gas type. We characterise the class of dark energy models that admit late time de Sitter attractor solution in terms of the potential function of corresponding conservative system. We argue that inclusion of dissipation effects makes the model more realistic because of its structural stabil...
Dissipation in ferrofluids Mesoscopic versus hydrodynamic theory
Müller, H W; Müller, Hanns Walter; Engel, Andreas
1999-01-01
Part of the field dependent dissipation in ferrofluids occurs due to the rotational motion of the ferromagnetic grains relative to the viscous flow of the carrier fluid. The classical theoretical description due to Shliomis uses a mesoscopic treatment of the particle motion to derive a relaxation equation for the non-equilibrium part of the magnetization. Complementary, the hydrodynamic approach of Liu involves only macroscopic quantities and results in dissipative Maxwell equations for the magnetic fields in the ferrofluid. Different stress tensors and constitutive equations lead to deviating theoretical predictions in those situations, where the magnetic relaxation processes cannot be considered instantaneous on the hydrodynamic time scale. We quantify these differences for two situations of experimental relevance namely a resting fluid in an oscillating oblique field and the damping of parametrically excited surface waves. The possibilities of an experimental differentiation between the two theoretical app...
Assessing relative volatility/intermittency/energy dissipation
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole E.; Pakkanen, Mikko S.; Schmiegel, Jürgen
2014-01-01
process in particular. This estimation method is motivated by the assessment of relative energy dissipation in empirical data of turbulence, but it is also applicable in other areas. We develop a probabilistic asymptotic theory for realised relative power variations of Brownian semistationary processes......, and introduce inference methods based on the theory. We also discuss how to extend the asymptotic theory to other classes of processes exhibiting stochastic volatility/intermittency. As an empirical application, we study relative energy dissipation in data of atmospheric turbulence.......We introduce the notion of relative volatility/intermittency and demonstrate how relative volatility statistics can be used to estimate consistently the temporal variation of volatility/intermittency when the data of interest are generated by a non-semimartingale, or a Brownian semistationary...
Heat dissipation in atomic-scale junctions
Lee, Woochul; Kim, Kyeongtae; Jeong, Wonho; Zotti, Linda Angela; Pauly, Fabian; Cuevas, Juan Carlos; Reddy, Pramod
2013-01-01
Atomic and single-molecule junctions represent the ultimate limit to the miniaturization of electrical circuits. They are also ideal platforms for testing quantum transport theories that are required to describe charge and energy transfer in novel functional nanometre-scale devices. Recent work has successfully probed electric and thermoelectric phenomena in atomic-scale junctions. However, heat dissipation and transport in atomic-scale devices remain poorly characterized owing to experimenta...
Supernova Remnant Evolution: from explosion to dissipation
Leahy, Denis
2016-01-01
Here is considered the full evolution of a spherical supernova remnant. We start by calculating the early time ejecta dominated stage and continue through the different phases of interaction with the circumstellar medium, and end with the dissipation and merger phase. The physical connection between the phases reveals new results. One is that the blast wave radius during the adiabatic phase is significantly smaller than it would be, if one does notaccount for the blast wave interaction with the ejecta.
Weierstrass solutions for dissipative BBM equation
Mancas, Stefan C.; Spradlin, Greg; Khanal, Harihar
2013-01-01
In this paper the effect of a small dissipation on waves is included to find exact solutions to the modified BBM equation. Using Lyapunov functions and dynamical systems theory, we prove that when viscosity is added to the BBM equation, in certain regions there still exist bounded traveling wave solutions in the form of solitary waves, periodic, and elliptic functions. By using the canonical form of Abel equation, the polynomial Appell invariant make the equation integrable in terms of Weiers...
Transport and Dissipation in Quantum Pumps
Avron, J. E.; Elgart, A.; Graf, G. M.; Sadun, L.
2003-01-01
This paper is about adiabatic transport in quantum pumps. The notion of ``energy shift'', a self-adjoint operator dual to the Wigner time delay, plays a role in our approach: It determines the current, the dissipation, the noise and the entropy currents in quantum pumps. We discuss the geometric and topological content of adiabatic transport and show that the mechanism of Thouless and Niu for quantized transport via Chern numbers cannot be realized in quantum pumps where Chern numbers necessa...
Using dissipative particle dynamics for modeling surfactants
ZHANG, YUCHEN; Ardekani, Arezoo M.
2015-01-01
Oil recovery is an industrial process that injects aqueous solutions into an oil reservoir to pump out crude oil and promote the oil production. The aqueous solution contains surfactants for reducing the interfacial tension (IFT) between aqueous phase and oil. The critical micelle concentration (CMC) is the concentration of surfactant above which micelles form and the interfacial tension reaches a plateau. Our research seeks to measure IFT and CMC for surfactants using dissipative particle dy...
Dissipative hydrodynamics and heavy ion collisions
Chaudhuri, A. K.
2008-01-01
Space-time evolution and subsequent particle production from minimally viscous ($\\eta/s$=0.08) QGP fluid is studied using the 2nd order Israel-Stewart's theory of dissipative relativistic fluid. Compared to ideal fluid, energy density or temperature evolves slowly in viscous dynamics. Particle yield at high $p_T$ is increased. Elliptic flow on the other hand decreases in viscous dynamics. Minimally viscous QGP fluid found to be consistent with a large number of experimental data.
Optical realization of the dissipative quantum oscillator.
Longhi, Stefano; Eaton, Shane M
2016-04-15
An optical realization of the damped quantum oscillator, based on transverse light dynamics in an optical resonator with slowly-moving mirrors, is theoretically suggested. The optical resonator setting provides a simple implementation of the time-dependent Caldirola-Kanai Hamiltonian of the dissipative quantum oscillator and enables the visualization of the effects of damped oscillations in the classical (ray optics) limit and wave packet collapse in the quantum (wave optics) regime.
Bloch oscillations in optical dissipative lattices.
Efremidis, Nikolaos K; Christodoulides, Demetrios N
2004-11-01
We show that Bloch oscillations are possible in dissipative optical waveguide lattices with a linearly varying propagation constant. These oscillations occur in spite of the fact that the Bloch wave packet experiences coupling gain and (or) loss. Experimentally, this process can be observed in different settings, such as in laser arrays and lattices of semiconductor optical amplifiers. In addition, we demonstrate that these systems can suppress instabilities arising from preferential mode noise growth.
Dissipative Quasigeostrophic Dynamics under Random Forcing
Brannan, James R.; Duan, Jinqiao; Wanner, Thomas
1998-01-01
The quasigeostrophic model is a simplified geophysical fluid model at asymptotically high rotation rate or at small Rossby number. We consider the quasigeostrophic equation with dissipation under random forcing in bounded domains. We show that global unique solutions exist for appropriate initial data. Unlike the deterministic quasigeostrophic equation whose well-posedness is well-known, there seems no rigorous result on global existence and uniqueness of the randomly forced quasigeostrophic ...
State transfer in dissipative and dephasing environments
Hu, Ming-Liang
2011-01-01
By diagonalization of a generalized superoperator for solving the master equation, we investigated effects of dissipative and dephasing environments on quantum state transfer, as well as entanglement distribution and creation in spin networks. Our results revealed that under the condition of the same decoherence rate $\\gamma$, the detrimental effects of the dissipative environment are more severe than that of the dephasing environment. Beside this, the critical time $t_c$ at which the transfer fidelity and the concurrence attain their maxima arrives at the asymptotic value $t_0=\\pi/2\\lambda$ quickly as the spin chain length $N$ increases. The transfer fidelity of an excitation at time $t_0$ is independent of $N$ when the system subjects to dissipative environment, while it decreases as $N$ increases when the system subjects to dephasing environment. The average fidelity displays three different patterns corresponding to $N=4r+1$, $N=4r-1$ and $N=2r$. For each pattern, the average fidelity at time $t_0$ is ind...
Dissipative Continuous Spontaneous Localization (CSL) model.
Smirne, Andrea; Bassi, Angelo
2015-01-01
Collapse models explain the absence of quantum superpositions at the macroscopic scale, while giving practically the same predictions as quantum mechanics for microscopic systems. The Continuous Spontaneous Localization (CSL) model is the most refined and studied among collapse models. A well-known problem of this model, and of similar ones, is the steady and unlimited increase of the energy induced by the collapse noise. Here we present the dissipative version of the CSL model, which guarantees a finite energy during the entire system's evolution, thus making a crucial step toward a realistic energy-conserving collapse model. This is achieved by introducing a non-linear stochastic modification of the Schrödinger equation, which represents the action of a dissipative finite-temperature collapse noise. The possibility to introduce dissipation within collapse models in a consistent way will have relevant impact on the experimental investigations of the CSL model, and therefore also on the testability of the quantum superposition principle. PMID:26243034
Turbulent dissipation and mixing in Prydz Bay
Institute of Scientific and Technical Information of China (English)
YANG Qingxuan; TIAN Jiwei; ZHAO Wei; XIE Lingling
2013-01-01
In this paper,we present measurements of velocity,temperature,salinity,and turbulence collected in Prydz Bay,Antarctica,during February,2005.The dissipation rates of turbulent kinetic energy (e) and diapycnal diffusivities (Kz) were estimated along a section in fiont of the Amery Ice Shelf.The dissipation rates and diapycnal diffusivities were spatially non-uniform,with higher values found in the western half of the section where e reached 10-7 W/kg and Kz reached 10-2 m2/s,about two and three orders of magnitude higher than those in the open ocean,respectively.In the western half of the section both the dissipation rates and diffusivities showed a high-low-high vertical structure.This vertical structure may have been determined by internal waves in the upper layer,where the ice shelf draft acts as a possible energy source,and by bottom-generated internal waves in the lower layer,where both tides and geostrophic currentsare possible energy sources.The intense diapycnal mixing revealed in our observations could contribute to the production of Antarctic Bottom Water in Prydz Bay.
Landing Energy Dissipation for Manned Reentry Vehicles
Fisher, Lloyd J., Jr.
1960-01-01
Analytical and experimental investigations have been made to determine the landing-energy-dissipation characteristics for several types of landing gear for manned reentry vehicles. The landing vehicles are considered in two categories: those having essentially vertical-descent paths, the parachute-supported vehicles, and those having essentially horizontal paths, the lifting vehicles. The energy-dissipation devices discussed are crushable materials such as foamed plastics and honeycomb for internal application in couch-support systems, yielding metal elements as part of the structure of capsules or as alternates for oleos in landing-gear struts, inflatable bags, braking rockets, and shaped surfaces for water impact. It appears feasible to readily evaluate landing-gear systems for internal or external application in hard-surface or water landings by using computational procedures and free-body landing techniques with dynamic models. The systems investigated have shown very interesting energy-dissipation characteristics over a considerable range of landing parameters. Acceptable gear can be developed along lines similar to those presented if stroke requirements and human-tolerance limits are considered.
Symmetry boundary condition in dissipative particle dynamics
Pal, Souvik; Lan, Chuanjin; Li, Zhen; Hirleman, E. Daniel; Ma, Yanbao
2015-07-01
Dissipative particle dynamics (DPD) is a coarse-grained particle method for modeling mesoscopic hydrodynamics. Most of the DPD simulations are carried out in 3D requiring remarkable computation time. For symmetric systems, this time can be reduced significantly by simulating only one half or one quarter of the systems. However, such simulations are not yet possible due to a lack of schemes to treat symmetric boundaries in DPD. In this study, we propose a numerical scheme for the implementation of the symmetric boundary condition (SBC) in both dissipative particle dynamics (DPD) and multibody dissipative particle dynamics (MDPD) using a combined ghost particles and specular reflection (CGPSR) method. We validate our scheme in four different configurations. The results demonstrate that our scheme can accurately reproduce the system properties, such as velocity, density and meniscus shapes of a full system with numerical simulations of a subsystem. Using a symmetric boundary condition for one half of the system, we demonstrate about 50% computation time saving in both DPD and MDPD. This approach for symmetric boundary treatment can be also applied to other coarse-grained particle methods such as Brownian and Langevin Dynamics to significantly reduce computation time.
Dissipative dark matter explains rotation curves
Foot, R
2015-01-01
Dissipative dark matter, where dark matter particles interact with a massless (or very light) boson, is studied. Such dark matter can arise in simple hidden sector gauge models, including those featuring an unbroken $U(1)'$ gauge symmetry, leading to a dark photon. Previous work has shown that such models can not only explain the LSS and CMB, but potentially also dark matter phenomena on small scales, such as the inferred cored structure of dark matter halos. In this picture, dark matter halos of disk galaxies not only cool via dissipative interactions but are also heated via ordinary supernovae (facilitated by an assumed photon - dark photon kinetic mixing interaction). This interaction between the dark matter halo and ordinary baryons, a very special feature of these types of models, plays a critical role in governing the physical properties of the dark matter halo. Here, we further study the implications of this type of dissipative dark matter for disk galaxies. Building on earlier work, we develop a simpl...
Energy localization in weakly dissipative resonant chains
Kovaleva, Agnessa
2016-08-01
Localization of energy in oscillator arrays has been of interest for a number of years, with special attention paid to the role of nonlinearity and discreteness in the formation of localized structures. This work examines a different type of energy localization arising due to the presence of dissipation in nonlinear resonance arrays. As a basic model, we consider a Klein-Gordon chain of finite length subjected to a harmonic excitation applied at an edge of the chain. It is shown that weak dissipation may be a key factor preventing the emergence of resonance in the entire chain, even if its nondissipative analog is entirely captured into resonance. The resulting process in the dissipative oscillator array represents large-amplitude resonant oscillations in a part of the chain adjacent to the actuator and small-amplitude oscillations in the distant part of the chain. The conditions of the emergence of resonance as well as the conditions of energy localization are derived. An agreement between the obtained analytical results and numerical simulations is demonstrated.
Characteristics of energy dissipation in hyperconcentrated flows
Institute of Scientific and Technical Information of China (English)
An-ping SHU; Qing-quan LIU; Yu-jun YI; Zhi-dong ZHANG
2008-01-01
An equilibrium equation for the turbulence energy in sediment-laden flows was derived on the basis of solid-liquid two-phase flow theory.The equation was simplified for two-dimensional,uniform,steady and fully developed turbulent hyperconcentrated flows.An energy efficiency coefficient of suspended-load motion was obtained from the turbulence energy equation,which is defined as the ratio of the sediment suspension energy to the turbulence energy of the sediment-laden flows.Laboratory experiments were conducted to investigate the characteristics of energy dissipation in hyperconcentrated flows.A total of 115 experimental runs were carried out,comprising 70 runs with natural sediments and 45 runs with cinder powder.Effects of sediment concentration on sediment suspension energy and flow resistance were analyzed and the relation between the energy efficiency coefficient of suspended-load motion and sediment concentration was established on the basis of experimental data.Furthermore,the characteristics of energy dissipation in hyperconcentrated flows were identified and described.It was found that the high sediment concentration does not increase the energy dissipation;on the contrary,it decreases flow resistance.
Heber, Ulrich
2012-09-01
Conservation of light energy in photosynthesis is possible only in hydrated photoautotrophs. It requires complex biochemistry and is limited in capacity. Charge separation in reaction centres of photosystem II initiates energy conservation but opens also the path to photooxidative damage. A main mechanism of photoprotection active in hydrated photoautotrophs is controlled by light. This is achieved by coupling light flux to the protonation of a special thylakoid protein which activates thermal energy dissipation. This mechanism facilitates the simultaneous occurrence of energy conservation and energy dissipation but cannot completely prevent damage by light. Continuous metabolic repair is required to compensate damage. More efficient photoprotection is needed by desiccation-tolerant photoautotrophs. Loss of water during desiccation activates ultra-fast energy dissipation in mosses and lichens. Desiccation-induced energy dissipation neither requires a protonation reaction nor light but photoprotection often increases when light is present during desiccation. Two different mechanisms contribute to photoprotection of desiccated photoautotrophs. One facilitates energy dissipation in the antenna of photosystem II which is faster than energy capture by functional reaction centres. When this is insufficient for full photoprotection, the other one permits energy dissipation in the reaction centres themselves. PMID:22527974
Tailored jump operators for purely dissipative quantum magnetism
Weimer, Hendrik
2016-01-01
I propose an archtitecture for the realization of dissipative quantum many-body spin models. The dissipative processes are mediated by interactions with auxiliary particles and lead to a widely tunable class of correlated quantum jump operators. These findings enable the investigation of purely dissipative spin models, where coherent dynamics is entirely absent. I provide a detailed review of a recently introduced variational method to analyze such dissipative quantum many-body systems, and I discuss a specific example in terms of a purely dissipative Heisenberg model, for which I find an additional disordered phase that is not present in the corresponding ground state phase diagram.
Su, Hongling; Li, Shengtai
2016-04-01
In this paper, we propose two new energy/dissipation-preserving Birkhoffian multi-symplectic methods (Birkhoffian and Birkhoffian box) for Maxwell's equations with dissipation terms. After investigating the non-autonomous and autonomous Birkhoffian formalism for Maxwell's equations with dissipation terms, we first apply a novel generating functional theory to the non-autonomous Birkhoffian formalism to propose our Birkhoffian scheme, and then implement a central box method to the autonomous Birkhoffian formalism to derive the Birkhoffian box scheme. We have obtained four formal local conservation laws and three formal energy global conservation laws. We have also proved that both of our derived schemes preserve the discrete version of the global/local conservation laws. Furthermore, the stability, dissipation and dispersion relations are also investigated for the schemes. Theoretical analysis shows that the schemes are unconditionally stable, dissipation-preserving for Maxwell's equations in a perfectly matched layer (PML) medium and have second order accuracy in both time and space. Numerical experiments for problems with exact theoretical results are given to demonstrate that the Birkhoffian multi-symplectic schemes are much more accurate in preserving energy than both the exponential finite-difference time-domain (FDTD) method and traditional Hamiltonian scheme. We also solve the electromagnetic pulse (EMP) propagation problem and the numerical results show that the Birkhoffian scheme recovers the magnitude of the current source and reaction history very well even after long time propagation.
Nonuniversality and Finite Dissipation in Decaying Magnetohydrodynamic Turbulence.
Linkmann, M F; Berera, A; McComb, W D; McKay, M E
2015-06-12
A model equation for the Reynolds number dependence of the dimensionless dissipation rate in freely decaying homogeneous magnetohydrodynamic turbulence in the absence of a mean magnetic field is derived from the real-space energy balance equation, leading to Cϵ=Cϵ,∞+C/R-+O(1/R-(2)), where R- is a generalized Reynolds number. The constant Cϵ,∞ describes the total energy transfer flux. This flux depends on magnetic and cross helicities, because these affect the nonlinear transfer of energy, suggesting that the value of Cϵ,∞ is not universal. Direct numerical simulations were conducted on up to 2048(3) grid points, showing good agreement between data and the model. The model suggests that the magnitude of cosmological-scale magnetic fields is controlled by the values of the vector field correlations. The ideas introduced here can be used to derive similar model equations for other turbulent systems.
Energy Technology Data Exchange (ETDEWEB)
Xu, T.; Senger, R.; Finsterle, S.
2011-02-01
After closure of an underground nuclear waste repository, the decay of radionuclides will raise temperature in the repository, and the bentonite buffer will resaturate by water inflow from the surrounding host rock. The perturbations from these thermal and hydrological processes are expected to dissipate within hundreds to a few thousand years. Here, we investigate coupled thermal-hydro-chemical processes and their effects on the short-term performance of a potential nuclear waste repository located in a clay formation. Using a simplified geometric configuration and abstracted hydraulic parameters of the clayey formation, we examine geochemical processes, coupled with thermo-hydrologic phenomena, and potential changes in porosity near the waste container during the early thermal period. The developed models were used for evaluating the mineral alterations and potential changes in porosity of the buffer, which can affect the repository performance. The results indicate that mineral alteration and associated changes in porosity induced by early thermal and hydrological processes are relatively small and are expected to not significantly affect flow and transport properties. Chlorite precipitation was obtained in all simulation cases. A maximum of one percent volume fraction of chlorite could be formed, whose process may reduce swelling and sorption capacity of bentonite clay, affecting the performance of the repository. llitisation process was not obtained from the present simulations.
Satellite Estimates of Precipitation-Induced Dissipation in the Atmosphere
Pauluis, Olivier; Dias, Juliana
2012-02-01
A substantial amount of frictional dissipation in the atmosphere occurs in the microphysical shear zones surrounding falling precipitation. The dissipation rate is computed here from recently available satellite retrieval from the Tropical Rainfall Measurement Missions and is found to average 1.8 watts per square meter between 30°S and 30°N. The geographical distribution of the precipitation-induced dissipation is closely tied to that of precipitation but also reveals a stronger dissipation rate for continental convection than for maritime convection. Because the precipitation-induced dissipation is of the same magnitude as the turbulent dissipation of the kinetic energy in the atmosphere, changes in the hydrological cycle could potentially have a direct impact on the amount of kinetic energy generated and dissipated by the atmospheric circulation.
International Nuclear Information System (INIS)
An experimental study is made of the drag coefficient, which is the characteristics of energy dissipation during oscillations of the tuning forks, immersed in liquid helium. The experiments were performed in the temperature range from 0.1 to 3.5 K covering both the range of a hydrodynamic flow, and the ballistic regime of transfer of thermal excitations of superfluid helium below 0.6 K. It is found that there is the frequency dependence of the drag coefficient in the hydrodynamic limit, when the main dissipation mechanism is the viscous friction of the fluid against the walls of the oscillating body at temperatures above 0.7 K. In this case, the drag coefficient is proportional to the square root of the frequency of oscillation, and its temperature dependence in He II is determined by the respective dependence of the normal component density of the normal component and the viscosity of the fluid. At lower temperatures, the dependence of drag coefficient on the frequency is not available, and the magnitude of the dissipative losses is determined only by the temperature dependence of the density of the normal component. At the same time in the entire range of temperatures value of dissipative losses depends on the geometry of the oscillating body.
James, Rob S; Tallis, Jason; Angilletta, Michael J
2015-01-01
In endotherms, such as mammals and birds, internal organs can specialise to function within a narrow thermal range. Consequently, these organs should become more sensitive to changes in body temperature. Yet, organs at the periphery of the body still experience considerable fluctuations in temperature, which could select for lower thermal sensitivity. We hypothesised that the performance of soleus muscle taken from the leg would depend less on temperature than would the performance of diaphragm muscle taken from the body core. Soleus and diaphragm muscles were isolated from mice and subjected to isometric and work-loop studies to analyse mechanical performance at temperatures between 15 and 40 °C. Across this thermal range, soleus muscle took longer to generate isometric force and longer to relax, and tended to produce greater normalised maximal force (stress) than did diaphragm muscle. The time required to produce half of maximal force during isometric tetanus and the time required to relax half of maximal force were both more sensitive to temperature in soleus than they were in diaphragm. However, thermal sensitivities of maximal force during isometric tetani were similar for both muscles. Consistent with our hypothesis, power output (the product of speed and force) was greater in magnitude and more thermally sensitive in diaphragm than it was in soleus. Our findings, when combined with previous observations of muscles from regionally endothermic fish, suggest that endothermy influences the thermal sensitivities of power output in core and peripheral muscles.
Institute of Scientific and Technical Information of China (English)
黄靖; 陈章位; 姚英豪
2011-01-01
根据热电相似性理论,建立基于半导体制冷片的聚合酶链反应(PCR)热循环系统的等效电路模型,将系统中各部件的热参数等效替换成相应的电路参数.利用该模型,分别分析在加热和制冷模式下,驱动电流、散热器热阻和样品块材料等因素对PCR热循环系统热性能的影响程度,得到了在各工作状况下样品块温度的稳态和动态曲线.结果表明:当驱动电流取最佳值Im时,系统可获得最佳制冷效果；驱动电流越大或材料的热容越小,系统升降温速度越快；材料不同对系统的Im值无明显影响；散热器热阻越小,样品块温度稳态值越低,系统的Im值越大.在设计时选择低热容的材料、低热阻的散热器以及最佳Im,可使系统获得最佳的热性能.%According to the thermal-electric analogies, an equivalent circuit model of the polymerase chain reaction (PCR) thermal cycle system based on thermoelectric coolers was established. System thermal parameters were replaced by equivalent electric parameters. With the equivalent circuit model, the system thermal performance was analyzed in cooling and heating modes respectively with different facts, such as driving current, sample block material, and heat sink thermal resistance. The transient and steady curves of the sample block temperature under various operation conditions were obtained. The result show that the system can achieve optimal cooling performance at optimal driving current 7m. The system heating and cooling rates are more rapid with larger driving current or smaller material thermal capacity. Different material has little impact on the value of Im. The steady values of sample block temperature is lower and Im has is larger with smaller heat sink thermal resistance. The optimal thermal performance of the PCR thermal cycle system is achieved by choosing sample black with low thermal capacity material, heat sink with low thermal resistance and driving current
Thermal evolution of the Kramer radiating star
Indian Academy of Sciences (India)
M Govender; S D Maharaj; L Mkhize; D B Lortan
2016-01-01
The Kramer radiating star uses the interior Schwarzschild solution as a seed solution to generate a model of dissipative collapse. We investigate the thermal behaviour of the radiating star by employing a causal heat transport equation. The causal temperature is explicitly determined for the first time by integrating the transport equation. We further show that the dissipation of energy to the exterior space-time renders the core more unstable than the cooler surface layers.
Langevin description of gauged scalar fields in a thermal bath
Miyamoto, Yuhei; Suyama, Teruaki; Yokoyama, Jun'ichi
2013-01-01
We study the dynamics of the oscillating gauged scalar field in a thermal bath. A Langevin type equation of motion of the scalar field, which contains both dissipation and fluctuation terms, is derived by using the real-time finite temperature effective action approach. The existence of the quantum fluctuation-dissipation relation between the non-local dissipation term and the Gaussian stochastic noise terms is verified. We find the noise variables are anti-correlated at equal-time. The dissipation rate for the each mode is also studied, which turns out to depend on the wavenumber.
Using AlN-Coated Heat Sink to Improve the Heat Dissipation of LED Packages
Directory of Open Access Journals (Sweden)
Jean Ming-Der
2016-01-01
Full Text Available This study optimizes aluminum nitride (AlN ceramics, in order to enhance the thermal performance of light-emitting diode (LED packages. AlN coatings are grown on copper/ aluminum substrates as a heat interface material, using an electrostatic spraying process. The effect of the deposition parameters on the coatings is determined. The thermal performance of AlN coated Cu/Al substrates is evaluated in terms of the heat dissipated and compared by measuring the LED case temperature. The structure and properties of the coating are also examined a scanning electron microscopy (SEM. In sum, the thermal performance of the LED is increased and good heat resistance characteristics are obtained. The results show that using AlN ceramic coating on a copper/aluminum substrate increases the thermal performance.
Optimization of Power Dissipation in Pipelined Analog-to-Digital Converter
Institute of Scientific and Technical Information of China (English)
徐江涛; 姚素英; 赵毅强; 张为; 李树荣; 张生才
2004-01-01
Power optimization for pipelined analog-to-digital converter(ADC) was studied. Operational principle of pipelined ADC was discussed and noise voltage caused by two important thermal noise sources, sampling switch and amplifier,was quantitatively analyzed. Method used to minimize power and the values under simple model were presented. Power can be saved by making the sampling and feedback capacitors scale down in the pipeline.And the size of capacitors was limited by thermal noise in high resolution ADC.The equivalent circuits of the two important thermal noise sources were established.Thermal noise was optimally distributed among the pipeline stages,and the relationship between scaling factor and closed loop gain was obtained for minimum power dissipation.Typical closed loop gain was 2 or 4 in pipeline ADC, and the corresponding scaling factor was 1.217 and 1.317.These results can serve as useful guidelines for designers to minimize the ADC's power consumption.
Non-Markovian dissipative quantum mechanics with stochastic trajectories
Energy Technology Data Exchange (ETDEWEB)
Koch, Werner
2010-09-09
All fields of physics - be it nuclear, atomic and molecular, solid state, or optical - offer examples of systems which are strongly influenced by the environment of the actual system under investigation. The scope of what is called ''the environment'' may vary, i.e., how far from the system of interest an interaction between the two does persist. Typically, however, it is much larger than the open system itself. Hence, a fully quantum mechanical treatment of the combined system without approximations and without limitations of the type of system is currently out of reach. With the single assumption of the environment to consist of an internally thermalized set of infinitely many harmonic oscillators, the seminal work of Stockburger and Grabert [Chem. Phys., 268:249-256, 2001] introduced an open system description that captures the environmental influence by means of a stochastic driving of the reduced system. The resulting stochastic Liouville-von Neumann equation describes the full non-Markovian dynamics without explicit memory but instead accounts for it implicitly through the correlations of the complex-valued noise forces. The present thesis provides a first application of the Stockburger-Grabert stochastic Liouville-von Neumann equation to the computation of the dynamics of anharmonic, continuous open systems. In particular, it is demonstrated that trajectory based propagators allow for the construction of a numerically stable propagation scheme. With this approach it becomes possible to achieve the tremendous increase of the noise sample count necessary to stochastically converge the results when investigating such systems with continuous variables. After a test against available analytic results for the dissipative harmonic oscillator, the approach is subsequently applied to the analysis of two different realistic, physical systems. As a first example, the dynamics of a dissipative molecular oscillator is investigated. Long time
Institute of Scientific and Technical Information of China (English)
周玲; 宋鹤山; 李崇; 郭彦青
2003-01-01
The dissipation of the field in the two-photon Jaynes-Cummings model (JCM) with degenerate atomic levels was studied. The initial degenerate atomic state affects the field coherence loss. When the degenerate atom is initially in an equal probability superposition state, the field coherence loss is smallest. It is found that the degeneracy of the atomic level increases the period of entanglement between the atom and the field. When the degeneracy was considered, the coherence properties of the field could be affected by the reservoir qualitatively, if a nonlinear two-photon process is involved. This is different from the dissipation of one-photon JCM with degenerate atomic levels.
Final Report Designing Biomimetic, Dissipative Material Systems
Energy Technology Data Exchange (ETDEWEB)
Balazs, Anna C.
2016-01-21
Throughout human history, new materials have been the foundation of transformative technologies: from bronze, paper, and ceramics to steel, silicon, and polymers, each material has enabled far-reaching advances. Today, another new class of materials is emerging—one with both the potential to provide radically new functions and to challenge our notion of what constitutes a “material”. These materials would harvest, transduce, or dissipate energy to perform autonomous, dynamic functions that mimic the behaviors of living organisms. Herein, we discuss the challenges and benefits of creating “dissipative” materials that can potentially blur the boundaries between living and non-living matter.
Dissipative Future Universe without Big Rip
Yadav, Anil Kumar
2010-01-01
The present study deals with dissipative future universe without big rip in context of Eckart formalism. The generalised chaplygin gas, characterised by equaction of state $p=-\\frac{A}{\\rho^\\frac{1}{\\alpha}}$, has been considered as a model for dark energy due to its dark-energy-like evolution at late time. It is demonstrated that, if the cosmic dark energy behaves like a fluid as well as chaplygin gas simultaneously then the big rip problem does not arise and the scale factor is found to be regular for all time.
Dissipative Structures At Laser-Solid Interactions
Nanai, Laszlo
1989-05-01
The questions which are discussed in this lecture refer to one of sections of laser-solid interactions, namely: to formation of different dissipative structures on the surface of metals and semiconductors when they are irradiated by intensive laser light in chemically active media (f.e.air). Some particular examples of the development at different spatial and time instabilities, periodic and stochastic structures, auto-wave processes are present-ed using testing materials vanadium metal and semiconducting V205 single crystals and light sources: cw and pulsed CO2 and YAG lasers.
Polarizable water model for Dissipative Particle Dynamics
Pivkin, Igor; Peter, Emanuel
2015-11-01
Dissipative Particle Dynamics (DPD) is an efficient particle-based method for modeling mesoscopic behavior of fluid systems. DPD forces conserve the momentum resulting in a correct description of hydrodynamic interactions. Polarizability has been introduced into some coarse-grained particle-based simulation methods; however it has not been done with DPD before. We developed a new polarizable coarse-grained water model for DPD, which employs long-range electrostatics and Drude oscillators. In this talk, we will present the model and its applications in simulations of membrane systems, where polarization effects play an essential role.
Dissipative plasmon solitons in graphene nanodisk arrays
Smirnova, Daria A; Smirnov, Lev A; Kivshar, Yuri S
2014-01-01
We study nonlinear modes in one-dimensional arrays of doped graphene nanodisks with Kerr-type nonlinear response in the presence of an external electric field. We present the theoretical model describing the evolution of the disks' polarizations, taking into account intrinsic graphene losses and dipole-dipole coupling between the graphene nanodisks. We reveal that this nonlinear system can support discrete dissipative scalar solitons of both longitudinal and transverse polarizations, as well as vector solitons composed of two mutually coupled polarization components. We demonstrate the formation of stable resting and moving localized modes under controlling guidance of the external driving field.
Assessing Relative Volatility/Intermittency/Energy Dissipation
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole E.; Pakkanen, Mikko; Schmiegel, Jürgen
process in particular. While this estimation method is motivated by the assessment of relative energy dissipation in empirical data of turbulence, we apply it also to energy price data. Moreover, we develop a probabilistic asymptotic theory for relative power variations of Brownian semistationary......We introduce the notion of relative volatility/intermittency and demonstrate how relative volatility statistics can be used to estimate consistently the temporal variation of volatility/intermittency even when the data of interest are generated by a non-semimartingale, or a Brownian semistationary...... processes and Ito semimartingales and discuss how it can be used for inference on relative volatility/intermittency....
García-Gil, Juan Carlos; Soler-Rovira, Pedro; López-de-Sa, Esther G.; Polo, Alfredo
2014-05-01
In semi-arid agricultural soils, seasonal dynamic of soil CO2 efflux (SCE) is highly variable. Based on soil respiration measurements the effects of different management systems (moldboard plowing, chisel and no-tillage) and the application of composted sludge (CS) and thermally-dried sewage sludge (TSS) was investigated in a long-term field experiment (28 years) conducted on a sandy-loam soil at the experimental station 'La Higueruela' (40o 03'N, 4o 24'W). Both organic amendments were applied at a rate of 30 Mg ha-1 prior to tillage practices. Unamended soils were used as control for each tillage system. SCE was moderate in late spring (2.2-11.8 μmol CO2 m-2 s-1) when amendments were applied and tillage was performed, markedly decreased in summer (0.4-3.2 μmol CO2 m-2 s-1), following a moderate increase in autumn (3.4-14.1 μmol CO2 m-2 s-1), rising sharply in October (5.6-39.8 μmol CO2 m-2 s-1 ). In winter, SCE was low (0.6-6.5 μmol CO2 m-2 s-1). In general, SCE was greater in chisel and moldboard tilled soils, and in CS and particularly TSS-amended soils, due to the addition of labile C with these amendments, meanwhile no-tillage soils exhibited smaller increases in C efflux throughout the seasons. Soil temperature controlled the seasonal variations of SCE. In summer, when drought occurs, a general decrease of SCE was observed due to a deficit in soil water content. After drought period SCE jumped to high values in response to rain events ('Birch effect') that changed soil moisture conditions. Soil drying in summer and rewetting in autumn may promotes some changes on the structure of soil microbial community, affecting associated metabolic processes, and enhancing a rapid mineralization of water-soluble organic C compounds and/or dead microbial biomass that acts as an energy source for soil microorganisms. To assess the effects of tillage and amendments on SCE, Q10 values were calculated. Data were grouped into three groups according to soil moisture (0
Advanced materials for thermal management of electronic packaging
Tong, Xingcun Colin
2011-01-01
The need for advanced thermal management materials in electronic packaging has been widely recognized as thermal challenges become barriers to the electronic industry's ability to provide continued improvements in device and system performance. With increased performance requirements for smaller, more capable, and more efficient electronic power devices, systems ranging from active electronically scanned radar arrays to web servers all require components that can dissipate heat efficiently. This requires that the materials have high capability of dissipating heat and maintaining compatibility
Mixing of blackbodies: entropy production and dissipation of sound waves in the early Universe
Khatri, R.; Sunyaev, R. A.; Chluba, J.
2012-07-01
Mixing of blackbodies with different temperatures creates a spectral distortion which, at lowest order, is a y-type distortion, indistinguishable from the thermal y-type distortion produced by the scattering of cosmic microwave background (CMB) photons by hot electrons residing in clusters of galaxies. This process occurs in the radiation-pressure dominated early Universe, when the primordial perturbations excite standing sound waves on entering the sound horizon. Photons from different phases of the sound waves, having different temperatures, diffuse through the electron-baryon plasma and mix together. This diffusion, with the length defined by Thomson scattering, dissipates sound waves and creates spectral distortions in the CMB. Of the total dissipated energy, 2/3 raises the average temperature of the blackbody part of spectrum, while 1/3 creates a distortion of y-type. It is well known that at redshifts 105 ≲ z ≲ 2 × 106, comptonization rapidly transforms y-distortions into a Bose-Einstein spectrum. The chemical potential of the Bose-Einstein spectrum is again 1/3 the value we would get if all the dissipated energy was injected into a blackbody spectrum but no extra photons were added. We study the mixing of blackbody spectra, emphasizing the thermodynamic point of view, and identifying spectral distortions with entropy creation. This allows us to obtain the main results connected with the dissipation of sound waves in the early Universe in a very simple way. We also show that mixing of blackbodies in general, and dissipation of sound waves in particular, leads to creation of entropy.
Camerin, Fabrizio; Frezzato, Diego
2016-08-01
This study focuses on fluctuating classical systems in contact with a thermal bath, and whose configurational energetics undergoes cyclic transformations due to interaction with external perturbing agents. Under the assumptions that the configurational dynamics is a stochastic Markov process in the overdamped regime and that the nonequilibrium configurational distribution remains close to the underlying equilibrium one, we derived an analytic approximation of the average dissipated energy per cycle in the asymptotic limit (i.e., after many cycles of perturbation). The energy dissipation is then readily translated into average entropy production, per cycle, in the environment. The accuracy of the approximation was tested by comparing the outcomes with the exact values obtained by stochastic simulations of a model case: a "particle on a ring" that fluctuates in a bistable potential perturbed in two different ways. As pointed out in previous studies on the stochastic resonance phenomenon, the dependence of the average dissipation on the perturbation period may unveil the inner spectrum of the system's fluctuation rates. In this respect, the analytical approximation presented here makes it possible to unveil the connection between average dissipation, intrinsic rates and modes of fluctuation of the system at the unperturbed equilibrium, and features of the perturbation itself (namely, the period of the cycle and the projections of the energy perturbation over the system's modes). The possibilities of employing the analytical results as a guide to devising and rationalizing a sort of "spectroscopic calorimetry" experiment, and of employing them in strategies aiming to optimize the system's features on the basis of a target average dissipation, are briefly discussed.
Grifoni, Milena; Paladino, Elisabetta
2008-11-01
Quantum dissipation has been the object of study within the physics and chemistry communities for many years. Despite this, the field is in constant evolution, largely due to the fact that novel systems where the understanding of dissipation and dephasing processes is of crucial importance have become experimentally accessible in recent years. Among the ongoing research themes, we mention the defeat of decoherence in solid state-based quantum bits (qubits) (e.g. superconducting qubits or quantum dot based qubits), or dissipation due to non-equilibrium Fermi reservoirs, as is the case for quantum transport through meso- and nanoscale structures. A close inspection of dissipation in such systems reveals that one has to deal with 'unconventional' environments, where common assumptions of, for example, linearity of the bath and/or equilibrium reservoir have to be abandoned. Even for linear baths at equilibrium it might occur that the bath presents some internal structure, due, for example, to the presence of localized bath modes. A large part of this focus issue is devoted to topics related to the rapidly developing fields of quantum computation and information with solid state nanodevices. In these implementations, single and two-qubit gates as well as quantum information transmission takes place in the presence of broadband noise that is typically non-Markovian and nonlinear. On both the experimental and theory side, understanding and defeating such noise sources has become a crucial step towards the implementation of efficient nanodevices. On a more fundamental level, electron and spin transport through quantum dot nanostructures may suffer from 'unconventional' dissipation mechanisms such as the simultaneous presence of spin relaxation and fermionic dissipation, or may represent themselves out of equilibrium baths for nearby mesoscopic systems. Finally, although not expected from the outset, the present collection of articles has revealed that different
López, G; González, G; Lopez, Gustavo; Lopez, Xaman-Ek; Gonzalez, Gabriel
2005-01-01
For a one-dimensional dissipative system with position depending coefficient, two constant of motion are deduce. These constants of motion bring about two Hamiltonians to describe the dynamics of same classical system. However, their quantization describe the dynamics of two completely different quantum systems.
Earliest stages of the nonequilibrium in axially symmetric, self-gravitating, dissipative fluids
Herrera, L.; Di Prisco, A.; Ospino, J.; Carot, J.
2016-09-01
We report a study on axially and reflection symmetric dissipative fluids, just after its departure from hydrostatic and thermal equilibrium, at the smallest time scale at which the first signs of dynamic evolution appear. Such a time scale is smaller than the thermal relaxation time, the thermal adjustment time, and the hydrostatic time. It is obtained that the onset of nonequilibrium will critically depend on a single function directly related to the time derivative of the vorticity. Among all fluid variables (at the time scale under consideration), only the tetrad component of the anisotropic tensor in the subspace orthogonal to the four-velocity and the Killing vector of axial symmetry, shows signs of dynamic evolution. Also, the first step toward a dissipative regime begins with a nonvanishing time derivative of the heat flux component along the meridional direction. The magnetic part of the Weyl tensor vanishes (not so its time derivative), indicating that the emission of gravitational radiation will occur at later times. Finally, the decreasing of the effective inertial mass density, associated to thermal effects, is clearly illustrated.
Dissipative processes in superfluid neutron stars
Mannarelli, Massimo; Manuel, Cristina
2010-01-01
We present some results about a novel damping mechanism of r-mode oscillations in neutron stars due to processes that change the number of protons, neutrons and electrons. Deviations from equilibrium of the number densities of the various species lead to the appearance in the Euler equations of the system of a dissipative mechanism, the so-called rocket effect. The evolution of the r-mode oscillations of a rotating neutron star are influenced by the rocket effect and we present estimates of the corresponding damping timescales. In the description of the system we employ a two-fluid model, with one fluid consisting of all the charged components locked together by the electromagnetic interaction, while the second fluid consists of superfluid neutrons. Both components can oscillate however the rocket effect can only efficiently damp the countermoving r-mode oscillations, with the two fluids oscillating out of phase. In our analysis we include the mutual friction dissipative process between the neutron superfluid...
Finite dissipation and intermittency in magnetohydrodynamics.
Mininni, P D; Pouquet, A
2009-08-01
We present an analysis of data stemming from numerical simulations of decaying magnetohydrodynamic (MHD) turbulence up to grid resolution of 1536(3) points and up to Taylor Reynolds number of approximately 1200 . The initial conditions are such that the initial velocity and magnetic fields are helical and in equipartition, while their correlation is negligible. Analyzing the data at the peak of dissipation, we show that the dissipation in MHD seems to asymptote to a constant as the Reynolds number increases, thereby strengthening the possibility of fast reconnection events in the solar environment for very large Reynolds numbers. Furthermore, intermittency of MHD flows, as determined by the spectrum of anomalous exponents of structure functions of the velocity and the magnetic field, is stronger than that of fluids, confirming earlier results; however, we also find that there is a measurable difference between the exponents of the velocity and those of the magnetic field, reminiscent of recent solar wind observations. Finally, we discuss the spectral scaling laws that arise in this flow. PMID:19792189
Dissipation in the effective field theory for hydrodynamics: First order effects
Endlich, Solomon; Porto, Rafael A; Wang, Junpu
2013-01-01
We introduce dissipative effects in the effective field theory of hydrodynamics. We do this in a model-independent fashion by coupling the long-distance degrees of freedom explicitly kept in the effective field theory to a generic sector that "lives in the fluid", which corresponds physically to the microscopic constituents of the fluid. At linear order in perturbations, the symmetries, the derivative expansion, and the assumption that this microscopic sector is thermalized, allow us to characterize the leading dissipative effects at low frequencies via three parameters only, which correspond to bulk viscosity, shear viscosity, and--in the presence of a conserved charge--heat conduction. Using our methods we re-derive the Kubo relations for these transport coefficients.
Nawrocki, Wojciech J; Santabarbara, Stefano; Mosebach, Laura; Wollman, Francis-André; Rappaport, Fabrice
2016-01-01
Photosynthesis converts sunlight into biologically useful compounds, thus fuelling practically the entire biosphere. This process involves two photosystems acting in series powered by light harvesting complexes (LHCs) that dramatically increase the energy flux to the reaction centres. These complexes are the main targets of the regulatory processes that allow photosynthetic organisms to thrive across a broad range of light intensities. In microalgae, one mechanism for adjusting the flow of energy to the photosystems, state transitions, has a much larger amplitude than in terrestrial plants, whereas thermal dissipation of energy, the dominant regulatory mechanism in plants, only takes place after acclimation to high light. Here we show that, at variance with recent reports, microalgal state transitions do not dissipate light energy but redistribute it between the two photosystems, thereby allowing a well-balanced influx of excitation energy. PMID:27249564
Extremely narrow spectrum of GRB110920A: further evidence for localised, subphotospheric dissipation
Iyyani, S; Ahlgren, B; Burgess, J M; Larsson, J; Pe'er, A; Lundman, C; Axelsson, M; McGlynn, S
2015-01-01
Much evidence points towards that the photosphere in the relativistic outflow in GRBs plays an important role in shaping the observed MeV spectrum. However, it is unclear whether the spectrum is fully produced by the photosphere or whether a substantial part of the spectrum is added by processes far above the photosphere. Here we make a detailed study of the $\\gamma-$ray emission from single pulse GRB110920A which has a spectrum that becomes extremely narrow towards the end of the burst. We show that the emission can be interpreted as Comptonisation of thermal photons by cold electrons in an unmagnetised outflow at an optical depth of $\\tau \\sim 20$. The electrons receive their energy by a local dissipation occurring close to the saturation radius. The main spectral component of GRB110920A and its evolution is thus, in this interpretation, fully explained by the emission from the photosphere including localised dissipation at high optical depths.
Particle production and dissipation caused by the Kaluza-Klein tower
Matsuda, Tomohiro
2012-01-01
Two-step dissipation is studied in supersymmetric models in which the field in motion couples to bulk fields in the higher dimensional space. Since the Kaluza-Klein tower of the intermediate field changes its mass-spectrum during the evolution, there could be back-reaction from the tower. Then the system may eventually cause significant dissipation of the kinetic energy if the tower is coupled to light fields in the thermal bath. To see what happens in the higher dimensional theory, we consider three models for the scenario, which are carefully prepared. In these models the extension is obvious but it does not disturb the original set-ups. The third model suggests that the evolution of the volume moduli may feel significant friction from the Kaluza-Klein tower.
Dissipation of oxytetracycline in soils under different redox conditions
Energy Technology Data Exchange (ETDEWEB)
Yang Jigeng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Department of Chemistry and Chemical Engineering, Hunan University of Arts and Sciences, Changde 415000 (China); Ying Guangguo, E-mail: guangguo.ying@gmail.co [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Zhou Lijun; Liu Shan; Zhao Jianliang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China)
2009-10-15
This study investigated the dissipation kinetics of oxytetracycline in soils under aerobic and anoxic conditions. Laboratory experiments showed that the dissipation of oxytetracycline in soil followed first-order reaction kinetics and its dissipation rates decreased with increasing concentration. Oxytetracycline dissipated faster in soil under aerobic conditions than under anoxic conditions. The half-lives for oxytetracycline in soil under aerobic conditions ranged between 29 and 56 days for non-sterile treatments and 99-120 days for sterile treatments, while under anoxic conditions the half-lives of oxytetracycline ranged between 43 and 62 days in the non-sterile soil and between 69 and 104 days in the sterile soil. This suggests microbes can degrade oxytetracycline in agricultural soil. Abiotic factors such as strong sorption onto soil components also played a role in the dissipation of oxytetracycline in soil. - Oxytetracycline dissipation in soils is influenced by redox conditions and soil properties.
Ohmic Dissipation in the Atmospheres of Hot Jupiters
Perna, Rosalba; Rauscher, Emily
2010-01-01
Hot Jupiter atmospheres exhibit fast, weakly-ionized winds. The interaction of these winds with the planetary magnetic field generates drag on the winds and leads to ohmic dissipation of the induced electric currents. We study the magnitude of ohmic dissipation in representative, three-dimensional atmospheric circulation models of the hot Jupiter HD 209458b. We find that ohmic dissipation can reach or exceed 1% of the stellar insolation power in the deepest atmospheric layers, in models with and without dragged winds. Such power, dissipated in the deep atmosphere, appears sufficient to slow down planetary contraction and explain the typically inflated radii of hot Jupiters. This atmospheric scenario does not require a top insulating layer or radial currents that penetrate deep in the planetary interior. Circulation in the deepest atmospheric layers may actually be driven by spatially non-uniform ohmic dissipation. A consistent treatment of magnetic drag and ohmic dissipation is required to further elucidate t...
Study on process and model of CBM dissipating
Institute of Scientific and Technical Information of China (English)
HONG Feng; SONG Yan; CHEN Zhenhong; ZHAO Mengjun; LIU Shaobo; QIN Shengfei; FU Guoyou
2005-01-01
Coal Bed Methane(CBM) occurs in coal seams in the states of adsorption gas, free gas and water-dissolved gas. Its dissipating starts with desorption, and then it dissipates outwards in the states of free gas and water-dissolved gas. The dissipating approach is classified to three patterns:Free gas in pores dissipates through the cover rocks; hydrocarbon molecules in the cap-rocks and reservoir diffuse because of concentration gradient; gas dissolving in water is directly taken away by water. According to the controlling factors of CBM conservation and considering the cover rocks,soleplate, hydrological region identification and dissipating theory, three geological models of CBM dissipating are built:closed system model, lateral hydrological closed model and open system model.
International Nuclear Information System (INIS)
The problem of abundance of inert gases in atmospheres of the Earth group planets is discussed. It is shown that introduction of He, Ne and 36Ar into the Mars and Mercury atmospheres with interplanetary dust and from other external sources require the presence of special mechanisms of losses for these gases. For the Mars atmosphere dissipation on atmosphere interaction with solar wind during the periods of anomalously low temperatures is a probable mechanisms of Ne and 36Ar losses. For the Mercury thermal dissipation for He and polar wind for other inert gases are possible. For all the planets of the Earth group dissipation on interaction with solar wind and introduction with interplanetary dust could play an important role at the early stages of evolution of planets
Busch, Xavier
2014-01-01
The two main predictions of quantum field theory in curved space-time, namely Hawking radiation and cosmological pair production, have not been directly tested and involve ultra high energy configurations. As a consequence, they should be considered with caution. Using the analogy with condensed matter systems, their analogue versions could be tested in the lab. Moreover, the high energy behavior of these systems is known and involves dispersion and dissipation, which regulate the theory at short distances. When considering experiments which aim to test the above predictions, there will also be a competition between the stimulated emission from thermal noise and the spontaneous emission out of vacuum. In order to measure these effects, one should thus compute the consequences of UV dispersion and dissipation, and identify observables able to establish that the spontaneous emission took place. In this thesis, we first analyze the effects of dispersion and dissipation on both Hawking radiation and pair particle...
Temperature dependence of the energy dissipation in dynamic force microscopy
Roll, Tino; Kunstmann, Tobias; Fendrich, Markus; Moeller, Rolf; Schleberger, Marika
2008-01-01
The dissipation of energy in dynamic force microscopy is usually described in terms of an adhesion hysteresis mechanism. This mechanism should become less efficient with increasing temperature. To verify this prediction we have measured topography and dissipation data with dynamic force microscopy in the temperature range from 100 K up to 300 K. We used 3,4,9,10-perylenetetracarboxylic-dianhydride (PTCDA) grown on KBr(001), both materials exhibiting a strong dissipation signal at large freque...
Power Dissipation of Memristor-Based Relaxation Oscillators
Directory of Open Access Journals (Sweden)
M. E. Fouda
2015-12-01
Full Text Available Recently, many reactance-less memristive relaxation oscillators were introduced, where the charging and discharging processes depend on memristors. In this paper, we investigate the power dissipation in different memristor based relaxation oscillators. General expressions for these memristive circuits as well as the power dissipation formulas for three different topologies are derived analytically. In addition, general expressions for the maximum and minimum power dissipation are calculated. Finally, the calculated expressions are verified using PSPICE simulations showing very good matching.
Power Dissipation of Memristor-Based Relaxation Oscillators
Fouda, M. E.; Radwan, A G
2015-01-01
Recently, many reactance-less memristive relaxation oscillators were introduced, where the charging and discharging processes depend on memristors. In this paper, we investigate the power dissipation in different memristor based relaxation oscillators. General expressions for these memristive circuits as well as the power dissipation formulas for three different topologies are derived analytically. In addition, general expressions for the maximum and minimum power dissipation are calculated. ...
Evaporation effects in the one-body dissipation mechanism
International Nuclear Information System (INIS)
Although the one-body dissipation mechanism has been successfully applied to the description of nuclear reactions, recent calculations suggest that quantum localization should completely suppress this dissipation mechanism. The particle evaporation process was not taken into account in those calculations. We show, through Fermi accelerator simulations, that this mechanism is a source of decoherence in the quantum dynamics of the system. This leads to a strong hindrance of quantum localization, and, as a consequence, to dissipation of collective energy
Evaporation effects in the one-body dissipation mechanism
Abal, G; Sicardi-Schifino, A C; Siri, R; Donangelo, R
2001-01-01
Although the one-body dissipation mechanism has been successfully applied to the description of nuclear reactions, recent calculations suggest that quantum localization should completely suppress this dissipation mechanism. The particle evaporation process was not taken into account in those calculations. We show, through Fermi accelerator simulations, that this mechanism is a source of decoherence in the quantum dynamics of the system. This leads to a strong hindrance of quantum localization, and, as a consequence, to dissipation of collective energy.
Dissipative energy as an indicator of material microstructural evolution
Connesson, N.; Maquin, F.; Pierron, F.
2010-06-01
In this study, the material microstructure evolution has been studied thanks to two indicators: the cumulated plastic strain and the energy dissipation due to internal friction under cyclic loading. An experimental procedure has been designed to underline the variations of the dissipative energy due to cold work on a DP600 specimen. The results showed that the dissipative energy increases with the plastic strain and can be used as an indicator of material microstructural evolution.
Dissipative energy as an indicator of material microstructural evolution
Directory of Open Access Journals (Sweden)
Pierron F.
2010-06-01
Full Text Available In this study, the material microstructure evolution has been studied thanks to two indicators: the cumulated plastic strain and the energy dissipation due to internal friction under cyclic loading. An experimental procedure has been designed to underline the variations of the dissipative energy due to cold work on a DP600 specimen. The results showed that the dissipative energy increases with the plastic strain and can be used as an indicator of material microstructural evolution.
Global scale-invariant dissipation in collisionless plasma turbulence
Kiyani, K H; Khotyaintsev, Yu V; Dunlop, M W
2009-01-01
A higher-order multiscale analysis of the dissipation range of collisionless plasma turbulence is presented using in-situ high-frequency magnetic field measurements from the Cluster spacecraft in a stationary interval of fast ambient solar wind. The observations, spanning five decades in temporal scales, show a crossover from multifractal intermittent turbulence in the inertial range to non-Gaussian monoscaling in the dissipation range. This presents a strong observational constraint on theories of dissipation mechanisms in turbulent collisionless plasmas.
Phase-slip-induced dissipation in an atomic Bose-Hubbard system.
McKay, D; White, M; Pasienski, M; DeMarco, B
2008-05-01
Phase-slips control dissipation in many bosonic systems, determining the critical velocity of superfluid helium and the generation of resistance in thin superconducting wires. Technological interest has been largely motivated by applications involving nanoscale superconducting circuit elements, such as standards based on quantum phase-slip junctions. Although phase slips caused by thermal fluctuations at high temperatures are well understood, controversy remains over the role of phase slips in small-scale superconductors--in solids, problems such as uncontrolled noise sources and disorder complicate their study and application. Here we show that phase slips can lead to dissipation in a clean and well-characterized Bose-Hubbard system, by experimentally studying the transport of ultracold atoms trapped in an optical lattice. In contrast to previous work, we explore a low-velocity regime described by the three-dimensional Bose-Hubbard model that is unaffected by instabilities, and we measure the effect of temperature on the dissipation strength. The damping rate of atomic motion (the analogue of electrical resistance in a solid) in the confining parabolic potential is well fitted by a model that includes finite damping at zero temperature. The low-temperature behaviour is consistent with the theory of quantum tunnelling of phase slips, whereas at higher temperatures a crossover consistent with a transition to thermal activation of phase slips is evident. Motion-induced features reminiscent of vortices and vortex rings associated with phase slips are also observed in time-of-flight imaging. These results clarify the role of phase slips in superfluid systems. They may also be of relevance in understanding the source of metallic phases observed in thin films, or serve as a test bed for theories of bosonic dissipation based upon variants of the Bose-Hubbard model. PMID:18451857
Phase-slip-induced dissipation in an atomic Bose-Hubbard system.
McKay, D; White, M; Pasienski, M; DeMarco, B
2008-05-01
Phase-slips control dissipation in many bosonic systems, determining the critical velocity of superfluid helium and the generation of resistance in thin superconducting wires. Technological interest has been largely motivated by applications involving nanoscale superconducting circuit elements, such as standards based on quantum phase-slip junctions. Although phase slips caused by thermal fluctuations at high temperatures are well understood, controversy remains over the role of phase slips in small-scale superconductors--in solids, problems such as uncontrolled noise sources and disorder complicate their study and application. Here we show that phase slips can lead to dissipation in a clean and well-characterized Bose-Hubbard system, by experimentally studying the transport of ultracold atoms trapped in an optical lattice. In contrast to previous work, we explore a low-velocity regime described by the three-dimensional Bose-Hubbard model that is unaffected by instabilities, and we measure the effect of temperature on the dissipation strength. The damping rate of atomic motion (the analogue of electrical resistance in a solid) in the confining parabolic potential is well fitted by a model that includes finite damping at zero temperature. The low-temperature behaviour is consistent with the theory of quantum tunnelling of phase slips, whereas at higher temperatures a crossover consistent with a transition to thermal activation of phase slips is evident. Motion-induced features reminiscent of vortices and vortex rings associated with phase slips are also observed in time-of-flight imaging. These results clarify the role of phase slips in superfluid systems. They may also be of relevance in understanding the source of metallic phases observed in thin films, or serve as a test bed for theories of bosonic dissipation based upon variants of the Bose-Hubbard model.
Rhén, Christin; Isacsson, Andreas
2016-03-01
When a contaminant diffuses on the surface of a nanomechanical resonator, the motions of the two become correlated. Despite being a high-order effect in the resonator-particle coupling, such correlations affect the system dynamics by inducing dissipation of the resonator energy. Here, we consider this diffusion-induced dissipation in the cases of multiple particles adsorbed on carbon nanotube and graphene resonators. By solving the stochastic equations of motion, we simulate the ringdown of the resonator, in order to determine the resonator energy decay rate. We find two different scalings with the number of adsorbed particles K and particle mass m . In the regime where the adsorbates are inertially trapped at an antinode of vibration, the dissipation rate Γ scales with the total adsorbed mass Γ ∝K m . In contrast, in the regime where particles diffuse freely over the resonator, the dissipation rate scales as the product of the total adsorbed mass and the individual particle mass: Γ ∝K m2 .
Kaihatu, J. M.; Goertz, J.; Sheremet, A.; Weiss, R.
2014-12-01
It has been observed that the front face of landfalling tsunamis often feature dispersive "fission" waves. These are short, almost monochromatic coherent waves which result from the piling up of water as the tsunami rapidly decelerates upon encountering land. Photographs taken during the 2004 Indian Ocean tsunami show these waves to resemble cnoidal waves in shape and have a spatial and temporal scale of the same order as swell waves. As part of our goal to study the tsunami in concert with other aspects of the physical environment, we investigate possible physical linkages between the background random swell, monochromatic fission waves, and the long-scale tsunami waves. This particular investigation involves the modification of the dissipation characteristics of random surface waves when interacting with a coherent wavefield (e.g., laboratory proxies for the fission wave or the tsunami). Data from laboratory experiments conducted at the Large Wave Flume at Oregon State University (part of the Network for Earthquake Engineering Simulation supported by the National Science Foundation) were analyzed and the dissipation characteristics inferred using a steepness-regulated instantaneous dissipation mechanism. It is shown that, for random waves, the instances of significant dissipation events temporally correspond to the appearance of high frequency energy in the time-frequency spectrogram. Furthermore, these observations are strongly affected by the presence of an underlying coherent wave signal, particularly in the case of interaction with a tsunami. We further discuss the possible effect of these interactions on the forces in the hydrodynamic field responsible for sediment transport.
Inflationary Weak Anisotropic Model with General Dissipation Coefficient
Sharif, M
2015-01-01
This paper explores the dynamics of warm intermediate and logamediate inflationary models during weak dissipative regime with a general form of dissipative coefficient. We analyze these models within the framework of locally rotationally symmetric Bianchi type I universe. In both cases, we evaluate solution of inflaton, effective scalar potential, dissipative coefficient, slow-roll parameters, scalar and tensor power spectra, scalar spectral index and tensor to scalar ratio under slow-roll approximation. We constrain the model parameters using recent data and conclude that anisotropic inflationary universe model with generalized dissipation coefficient remains compatible with WMAP9, Planck and BICEP2 data.
INFLUENCING FACTORS FOR THE ENERGY DISSIPATION RATIO OF STEPPED SPILLWAYS
Institute of Scientific and Technical Information of China (English)
CHEN Qun; DAI Guang-qing; ZHU Fen-qing
2005-01-01
In order to search for the measure to increase the energy dissipation ratio of stepped spillways, some main influencing factors for the energy dissipation ratio of stepped spillways, such as unit discharge, dam slope, height of step and so on, were studied. The results show that the energy dissipation ratio decreases with the increase in the unit discharge and increases as the slope becomes gentle. The effects of step height on the energy dissipation ratio are closely related to unit discharge. If the unit discharge is smaller, the change of energy dissipation ratio with step height becomes greater. While, if the unit discharge is greater, the influence of step height on energy dissipation ratio is very little. According to the distributions of the turbulence kinetic energy and turbulence dissipation rate obtained by numerical simulation, the basic reason of the decrease of energy dissipation ratio with the increase in the unit discharge was discussed and some specific measures to increase the energy dissipation ratio were suggested.
Thermal stress, human performance, and physical employment standards.
Cheung, Stephen S; Lee, Jason K W; Oksa, Juha
2016-06-01
Many physically demanding occupations in both developed and developing economies involve exposure to extreme thermal environments that can affect work capacity and ultimately health. Thermal extremes may be present in either an outdoor or an indoor work environment, and can be due to a combination of the natural or artificial ambient environment, the rate of metabolic heat generation from physical work, processes specific to the workplace (e.g., steel manufacturing), or through the requirement for protective clothing impairing heat dissipation. Together, thermal exposure can elicit acute impairment of work capacity and also chronic effects on health, greatly contributing to worker health risk and reduced productivity. Surprisingly, in most occupations even in developed economies, there are rarely any standards regarding enforced heat or cold safety for workers. Furthermore, specific physical employment standards or accommodations for thermal stressors are rare, with workers commonly tested under near-perfect conditions. This review surveys the major occupational impact of thermal extremes and existing employment standards, proposing guidelines for improvement and areas for future research. PMID:27277564
水泥回转窑热工测量准确性的影响因素分析%Factors affecting thermal measurement accuracy of cement rotary kiln
Institute of Scientific and Technical Information of China (English)
袁秀霞
2014-01-01
Thermal measurement of cement rotary kiln is a complex process, there are many factors affecting the accuracy of measure-ment results. Based on many years of rotary kiln thermal measuring experience, for four aspects of test condition selection, scheme;in-strument management and data processing, main factors affecting thermal measurement accuracy were summarized as well as the meth-od of reducing testing data deviation.%水泥回转窑的热工测量是个复杂的过程，测量结果准确性的影响因素较多。根据多年水泥回转窑热工测量经验，从测试条件的选取、测试方案的制定、测试仪器设备的管理和测试数据的处理四个方面，分别总结了影响热工测量数据准确性的主要因素以及减少测试数据出现偏差的方法。
Dissipative processes in light heavy ion collisions
International Nuclear Information System (INIS)
The deep inelastic processes in light heavy ion collisions were systematically studied in the reactions 19 F(111.4, 125, 136.9 MeV) + 12 C, 27 Al, and 27 Al(140.14 MeV) + 12 C, 27 Al using the experimental device DRACULA mounted at LNS-Catania. ΔE - E identification, continuous measurements of energy and angle, mass identification by time-of-flight and γ-multiplicity measurements have been performed for the main reaction products. The double differential cross sections, as a function of different experimental observables, show similar trends with those observed for much heavier systems. Thus, a complete dynamics, from quasielastic to complete dissipation regime, is evidenced even in the case of such light systems and microscopic models could be described. The variance of the charge distribution and the amount of energy dissipated per exchanged nucleon for light systems follow the same type of correlations as medium and heavy systems which have been explained within very simple hypotheses. The interaction time, estimated from the experimental angular distributions for different windows of total kinetic energy, varies from some units of 10-23 sec up to the order of 10-21 sec, showing the presence of fast and slow processes relative to the transit time value of ∼ 5·10-22 sec. The increasing value of the interaction time, represented as a function of the atomic number (Z) and total kinetic energy loss, shows that isotopes with atomic numbers farther from the projectile corresponding value can be populated. Thus, integrated angular distributions usually presented in the literature, becoming flatter with increasing number of transferred nucleons, reflect the necessity of a larger interaction time in order to reach products very different from the projectile. For the same degree of inelasticity of the reaction, the estimated mean lifetime is roughly the same for every atomic number value in the exit channel. This suggests a diffusion-type process. After describing
EXPERIMENTAL STUDY ON WAVE ENERGY DISSIPATION AND COHESIVE SEDIMENT TRANSPORT IN SILT COAST
Institute of Scientific and Technical Information of China (English)
Shixiong HU; Onyx WAI
2001-01-01
The interaction between the wave and fluid mud layer plays an important role in the development of silt coast. Sediment is essentially transported in the form of rheological flow of mud layer under the wave action, and on the other hand, the fluid mud layer damps the wave considerably. This paper studies the laws of wave energy dissipation and mud bed deformation, and the movement of mud layer through laboratory experiments. The results show that the wave energy dissipation follows an exponential law along the propagation distance. The bulk density of the mud layer affects the rate of the wave energy dissipation greatly. The wave damping coefficient (Ki) is a fuction of the mud density affected greatly by the relative wave height (H/h).Analysis also indicates that the mud density affect the rate of mud transport and the moving velocity (Vmax) of the surface mud is inversely proportional to the mud density. Both the relative wave height (H/h) and wave-damping coefficient (Ki) are proportional to the Vmax. Analysis also shows that the mud transport rate (Tr) is proportional to the wave damping rate (1-H0/H15), the relative wave height (H/h),and inversely proportional to the volume concentration (Cv) and dimensionless coefficient of H/gT2.
Characterization of a New Heat Dissipation Matric Potential Sensor
Directory of Open Access Journals (Sweden)
Rolf Krebs
2013-01-01
Full Text Available Soil moisture sensors can help to reduce the amount of water needed for irrigation. In this paper we describe the PlantCare soil moisture sensor as a new type of heat dissipation sensor, its calibration and the correction for temperature changes. With the PlantCare sensor it is possible to measure the matric potential indirectly to monitor or control irrigation. This sensor is based on thermal properties of a synthetic felt. After a defined heating phase the cooling time to a threshold temperature is a function of the water content in the synthetic felt. The water content in this porous matrix is controlled by the matric potential in the surrounding soil. Calibration measurements have shown that the sensor is most sensitive to −400 hPa and allows lower sensitivity measurements to −800 hPa. The disturbing effect of the temperature change during the measurement on the cooling time can be corrected by a linear function and the differences among sensors are minimized by a two point calibration.
Characterization of a new heat dissipation matric potential sensor.
Matile, Luzius; Berger, Roman; Wächter, Daniel; Krebs, Rolf
2013-01-01
Soil moisture sensors can help to reduce the amount of water needed for irrigation. In this paper we describe the PlantCare soil moisture sensor as a new type of heat dissipation sensor, its calibration and the correction for temperature changes. With the PlantCare sensor it is possible to measure the matric potential indirectly to monitor or control irrigation. This sensor is based on thermal properties of a synthetic felt. After a defined heating phase the cooling time to a threshold temperature is a function of the water content in the synthetic felt. The water content in this porous matrix is controlled by the matric potential in the surrounding soil. Calibration measurements have shown that the sensor is most sensitive to -400 hPa and allows lower sensitivity measurements to -800 hPa. The disturbing effect of the temperature change during the measurement on the cooling time can be corrected by a linear function and the differences among sensors are minimized by a two point calibration. PMID:23344384
Mapping of dissipative particle dynamics in fluctuating hydrodynamics simulations
Qiao, R
2008-01-01
Dissipative particle dynamics (DPD) is a novel particle method for mesoscale modeling of complex fluids. DPD particles are often thought to represent packets of real atoms, and the physical scale probed in DPD models are determined by the mapping of DPD variables to the corresponding physical quantities. However, the non-uniqueness of such mapping has led to difficulties in setting up simulations to mimic real systems and in interpreting results. For modeling transport phenomena where thermal fluctuations are important (e.g., fluctuating hydrodynamics), an area particularly suited for DPD method, we propose that DPD fluid particles should be viewed as only 1) to provide a medium in which the momentum and energy are transferred according to the hydrodynamic laws and 2) to provide objects immersed in the DPD fluids the proper random "kicks" such that these objects exhibit correct fluctuation behaviors at the macroscopic scale. We show that, in such a case, the choice of system temperature and mapping of DPD sca...
Optimized Structures for Low-Profile Phase Change Thermal Spreaders
Sharratt, Stephen Andrew
Thin, low-profile phase change thermal spreaders can provide cooling solutions for some of today's most pressing heat flux dissipation issues. These thermal issues are only expected to increase as future electronic circuitry requirements lead to denser and potentially 3D chip packaging. Phase change based heat spreaders, such as heat pipes or vapor chambers, can provide a practical solution for effectively dissipating large heat fluxes. This thesis reports a comprehensive study of state-of-the-art capillary pumped wick structures using computational modeling, micro wick fabrication, and experimental analysis. Modeling efforts focus on predicting the shape of the liquid meniscus inside a complicated 3D wick structure. It is shown that this liquid shape can drastically affect the wick's thermal resistance. In addition, knowledge of the liquid meniscus shape allows for the computation of key parameters such as permeability and capillary pressure which are necessary for predicting the maximum heat flux. After the model is validated by comparison to experimental results, the wick structure is optimized so as to decrease overall wick thermal resistance and increase the maximum capillary limited heat flux before dryout. The optimized structures are then fabricated out of both silicon and copper using both traditional and novel micro-fabrication techniques. The wicks are made super-hydrophilic using chemical and thermal oxidation schemes. A sintered monolayer of Cu particles is fabricated and analyzed as well. The fabricated wick structures are experimentally tested for their heat transfer performance inside a well controlled copper vacuum chamber. Heat fluxes as high as 170 W/cm2 are realized for Cu wicks with structure heights of 100 μm. The structures optimized for both minimized thermal resistance and high liquid supply ability perform much better than their non-optimized counterparts. The super-hydrophilic oxidation scheme is found to drastically increase the maximum
Longitudinal magnetohydrodynamics oscillations in dissipative, cooling coronal loops
International Nuclear Information System (INIS)
This paper investigates the effect of cooling on standing slow magnetosonic waves in coronal magnetic loops. The damping mechanism taken into account is thermal conduction that is a viable candidate for dissipation of slow magnetosonic waves in coronal loops. In contrast to earlier studies, here we assume that the characteristic damping time due to thermal conduction is not small, but arbitrary, and can be of the order of the oscillation period, i.e., a temporally varying plasma is considered. The approximation of low-beta plasma enables us to neglect the magnetic field perturbation when studying longitudinal waves and consider, instead, a one-dimensional motion that allows a reliable first insight into the problem. The background plasma temperature is assumed to be decaying exponentially with time, with the characteristic cooling timescale much larger than the oscillation period. This assumption enables us to use the WKB method to study the evolution of the oscillation amplitude analytically. Using this method we obtain the equation governing the oscillation amplitude. The analytical expressions determining the wave properties are evaluated numerically to investigate the evolution of the oscillation frequency and amplitude with time. The results show that the oscillation period increases with time due to the effect of plasma cooling. The plasma cooling also amplifies the amplitude of oscillations in relatively cool coronal loops, whereas, for very hot coronal loop oscillations the damping rate is enhanced by the cooling. We find that the critical point for which the amplification becomes dominant over the damping is in the region of 4 MK. These theoretical results may serve as impetus for developing the tools of solar magneto-seismology in dynamic plasmas.
An extended dissipative particle dynamics model
Cotter, C J
2003-01-01
The method of dissipative particle dynamics (DPD) was introduced by Hoogerbrugge & Koelman to study meso-scale material processes. The theoretical investigation of the DPD method was initiated by Espanol who used a Fokker-Planck formulation of the DPD method and applied the Mori-Zwanzig projection operator calculus to obtain the equations of hydrodynamics for DPD. A current limitation of DPD is that it requires a clear separation of scales between the resolved and unresolved processes. In this note, we suggest a simple extension of DPD that allows for inclusion of unresolved processes with exponentially decaying variance for any value of the decay rate. The main point of the extension is that it is as easy to implement as DPD in a numerical algorithm.
Energy relaxation of a dissipative quantum oscillator
Energy Technology Data Exchange (ETDEWEB)
Kumar, Pradeep; Pollak, Eli [Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot (Israel)
2014-12-21
The dissipative harmonic oscillator is studied as a model for vibrational relaxation in a liquid environment. Continuum limit expressions are derived for the time-dependent average energy, average width of the population, and the vibrational population itself. The effect of the magnitude of the solute-solvent interaction, expressed in terms of a friction coefficient, solvent temperature, and initial energy of the oscillator on the relaxation has been studied. These results shed light on the recent femtosecond stimulated Raman scattering probe of the 1570 cm{sup −1} −C=C− stretching mode of trans-Stilbene in the first (S{sub 1}) excited electronic state. When the oscillator is initially cold with respect to the bath temperature, its average energy and width increase in time. When it is initially hot, the average energy and width decrease with time in qualitative agreement with the experimental observations.
Dissipative Control of the State Delayed Systems
Institute of Scientific and Technical Information of China (English)
FU Yu-sun; TIAN Zuo-hua; SHI Song-jiao
2001-01-01
In this note, the dissipative control problem of the general quadratic supply rate for state delayed systems is considered. A systematic approach is used in this work so that a sufficient condition on the existence of a delay-independent state feedback controller is given. In addition, a sufficient condition on the existence of a delay-dependent state feedback is presented. Our solutions are expressed in terms of matrix inequalities that can be solved by numerical method. The delay-dependent controller might be less conservative than the delay-independent one in the sense that the delay-dependent case may have a solution for a larger class of systems than that for delay-independent case.
Two-dimensional dissipative gap solitons
International Nuclear Information System (INIS)
We introduce a model which integrates the complex Ginzburg-Landau equation in two dimensions (2Ds) with the linear-cubic-quintic combination of loss and gain terms, self-defocusing nonlinearity, and a periodic potential. In this system, stable 2D dissipative gap solitons (DGSs) are constructed, both fundamental and vortical ones. The soliton families belong to the first finite band gap of the system's linear spectrum. The solutions are obtained in a numerical form and also by means of an analytical approximation, which combines the variational description of the shape of the fundamental and vortical solitons and the balance equation for their total power. The analytical results agree with numerical findings. The model may be implemented as a laser medium in a bulk self-defocusing optical waveguide equipped with a transverse 2D grating, the predicted DGSs representing spatial solitons in this setting.
Neural network training as a dissipative process.
Gori, Marco; Maggini, Marco; Rossi, Alessandro
2016-09-01
This paper analyzes the practical issues and reports some results on a theory in which learning is modeled as a continuous temporal process driven by laws describing the interactions of intelligent agents with their own environment. The classic regularization framework is paired with the idea of temporal manifolds by introducing the principle of least cognitive action, which is inspired by the related principle of mechanics. The introduction of the counterparts of the kinetic and potential energy leads to an interpretation of learning as a dissipative process. As an example, we apply the theory to supervised learning in neural networks and show that the corresponding Euler-Lagrange differential equations can be connected to the classic gradient descent algorithm on the supervised pairs. We give preliminary experiments to confirm the soundness of the theory. PMID:27389569
Dissipative effects on quarkonium spectral functions
Buyukdag, Yusuf
2015-01-01
Quarkonium at finite temperature is described as an open quantum system whose dynamics are determined by a potential $V_R({\\bf x})$ and drag coefficient $\\eta$, using a path integral with a non-local term. Path-integral Monte Carlo calculations determine the Euclidean Green function for this system to an accuracy greater than one part in a thousand and the maximum entropy method is used to determine the spectral function; challenges facing any kind of deconvolution are discussed in detail with the aim of developing intuition for when deconvolution is possible. Significant changes to the quarkonium spectral function in the $1S$ channel are found, suggesting that any description of quarkonium at finite temperature, using a potential, must also carefully consider the effect of dissipation.
Energy dissipation in Exosat tanks: Test results
Marce, J. L.; Torres, L.; Assemat, D.; Michel, S.
1981-03-01
Results of tests performed with inertia ratio and filling ratio scanning on Ariane tanks are presented. The Exosat launch requires the use of a fourth stage (P 0.7). The Exosat + P 0.7 assembly is spin stabilized with a spin rate of 50 rpm during transfer orbit. The unstable assembly is fitted with an active nutation damping system. To size this, it is necessary to know the time constant of nutation build up essentially due to fuel motion in the propane tanks and the hydrazine tank of Exosat. The major source of dissipation is the hydrazine tank for which an hysteresis phenomenon on diaphragm position was observed; the worst time constants of nutation build up, deduced from tests are 2.5 mn before P 0.7 and 1.9 mn after P 0.7 firing, taking into account the appropriate safety factors.
Polarizable protein model for Dissipative Particle Dynamics
Peter, Emanuel; Lykov, Kirill; Pivkin, Igor
2015-11-01
In this talk, we present a novel polarizable protein model for the Dissipative Particle Dynamics (DPD) simulation technique, a coarse-grained particle-based method widely used in modeling of fluid systems at the mesoscale. We employ long-range electrostatics and Drude oscillators in combination with a newly developed polarizable water model. The protein in our model is resembled by a polarizable backbone and a simplified representation of the sidechains. We define the model parameters using the experimental structures of 2 proteins: TrpZip2 and TrpCage. We validate the model on folding of five other proteins and demonstrate that it successfully predicts folding of these proteins into their native conformations. As a perspective of this model, we will give a short outlook on simulations of protein aggregation in the bulk and near a model membrane, a relevant process in several Amyloid diseases, e.g. Alzheimer's and Diabetes II.
Dissipative Quantum Metrology with Spin Cat States
Huang, Jiahao; Zhong, Honghua; Ke, Yongguan; Lee, Chaohong
2014-01-01
We present a robust high-precision phase estimation scheme via spin cat states in the presence of particle losses. The input Greenberger-Horne-Zeilinger (GHZ) state, which may achieve the Heisenberg-limited measurement in the absence of particle losses, becomes fragile against particle losses and its achieved precision becomes even worse than the standard quantum limit (SQL). However, the input spin cat states, a kind of non-Gaussian entangled states in superposition of two spin coherent states, are of excellent robustness against particle losses and the achieved precision may still beat the SQL. For realistic measurements based upon our scheme, comparing with the population measurement, the parity measurement is more suitable for yielding higher precisions. In phase measurement with realistic dissipative systems of bosonic particles, our scheme provides a robust and realizable way to achieve high-precision measurements beyond the SQL.
Strong Dissipative Behavior in Quantum Field Theory
Berera, A; Ramos, R O; Berera, Arjun; Gleiser, Marcelo; Ramos, Rudnei O.
1998-01-01
We study under which conditions an overdamped regime can be attained in the dynamic evolution of a quantum field configuration. Using a real-time formulation of finite temperature field theory, we compute the effective evolution equation of a scalar field configuration, quadratically interacting with a given set of other scalar fields. We then show that, in the overdamped regime, the dissipative kernel in the field equation of motion is closely related to the shear viscosity coefficient, as computed in scalar field theory at finite temperature. The effective dynamics is equivalent to a time-dependent Ginzburg-Landau description of the approach to equilibrium in phenomenological theories of phase transitions. Applications of our results, including a recently proposed inflationary scenario called ``warm inflation'', are discussed.
A quantum photonic dissipative transport theory
Lei, Chan U.; Zhang, Wei-Min
2012-05-01
In this paper, a quantum transport theory for describing photonic dissipative transport dynamics in nanophotonics is developed. The nanophotonic devices concerned in this paper consist of on-chip all-optical integrated circuits incorporating photonic bandgap waveguides and driven resonators embedded in nanostructured photonic crystals. The photonic transport through waveguides is entirely determined from the exact master equation of the driven resonators, which is obtained by explicitly eliminating all the degrees of freedom of the waveguides (treated as reservoirs). Back-reactions from the reservoirs are fully taken into account. The relation between the driven photonic dynamics and photocurrents is obtained explicitly. The non-Markovian memory structure and quantum decoherence dynamics in photonic transport can then be fully addressed. As an illustration, the theory is utilized to study the transport dynamics of a photonic transistor consisting of a nanocavity coupled to two waveguides in photonic crystals. The controllability of photonic transport through the external driven field is demonstrated.
Institute of Scientific and Technical Information of China (English)
Payel Das; Mridula Kanoria
2009-01-01
The generalized thermo-elasticity theory, i.e., Green and Naghdi (G-N) III theory, with energy dissipation (TEWED) is employed in the study of time-harmonic plane wave propagation in an unbounded, perfectly electrically conducting elastic medium subject to primary uniform magnetic field. A more general dispersion equation with com-plex coefficients is obtained for coupled magneto-thermo-elastic wave solved in complex domain by using the Leguerre's method. It reveals that the coupled magneto-thermo-elastic wave corresponds to modified dilatational and thermal wave propagation with finite speeds modified by finite thermal wave speeds, thermo-elastic coupling, thermal diffusivity, and the external magnetic field. Numerical results for a copper-like material are presented.
Dissipative or conservative cosmology with dark energy?
International Nuclear Information System (INIS)
All evolutional paths for all admissible initial conditions of FRW cosmological models with dissipative dust fluid (described by dark matter, baryonic matter and dark energy) are analyzed using dynamical system approach. With that approach, one is able to see how generic the class of solutions leading to the desired property-acceleration-is. The theory of dynamical systems also offers a possibility of investigating all possible solutions and their stability with tools of Newtonian mechanics of a particle moving in a one-dimensional potential which is parameterized by the cosmological scale factor. We demonstrate that flat cosmology with bulk viscosity can be treated as a conservative system with a potential function of the Chaplygin gas type. We characterize the class of dark energy models that admit late time de Sitter attractor solution in terms of the potential function of corresponding conservative system. We argue that inclusion of dissipation effects makes the model more realistic because of its structural stability. We also confront viscous models with SNIa observations. The best fitted models are obtained by minimizing the χ2 function which is illustrated by residuals and χ2 levels in the space of model independent parameters. The general conclusion is that SNIa data supports the viscous model without the cosmological constant. The obtained values of χ2 statistic are comparable for both the viscous model and ΛCDM model. The Bayesian information criteria are used to compare the models with different power-law parameterization of viscous effects. Our result of this analysis shows that SNIa data supports viscous cosmology more than the ΛCDM model if the coefficient in viscosity parameterization is fixed. The Bayes factor is also used to obtain the posterior probability of the model
Institute of Scientific and Technical Information of China (English)
2008-01-01
By taking equivalent thermal resistance, which reflects the average heat conduc- tion effect and is defined based on entransy dissipation, as optimization objective, the "volume to point" constructal problem of how to discharge the heat generated in a fixed volume to a heat sink on the border through relatively high conductive link is re-analyzed and re-optimized in this paper. The constructal shape of the control volume with the best average heat conduction effect is deduced. For the elemental area and the first order construct assembly, when the thermal current density in the high conductive link is linear with the length, the optimized shapes of assemble based on the minimization of entransy dissipation are the same as those based on minimization of maximum temperature difference, and the mean tem- perature difference is 2/3 of the maximum temperature difference. For the second and higher order construct assemblies, the thermal current densities in the high conductive link are not linear with the length, and the optimized shapes of assem- ble based on the minimization of entransy dissipation are different from those based on minimization of maximum temperature difference. For the same parame- ters, the constructs based on minimization of entransy dissipation and the con- structs based on minimization of maximum temperature difference are compared, and the results show that the constructs based on entransy dissipation can de- crease the mean temperature difference better than the constructs based on mini- mization of maximum temperature difference. But with the increase of the number of the order, the mean temperature difference does not always decrease, and there exist some fluctuations. Because the idea of entransy describes the heat transfer ability more suitably, all of the heat conduction constructal problems may be re-optimized based on it.
Perry, Jennifer J; Yousef, Ahmed E
2013-02-01
Infection of laying hens with Salmonella enterica serovar Enteritidis leads to deposition of the pathogen into the albumen or yolk of forming eggs. Heat treatment can inactivate internalized Salmonella Enteritidis in shell eggs, but factors such as the nature and location of contamination may influence the efficacy of thermal treatments. In the current research, natural contamination was mimicked by introducing small inocula of Salmonella Enteritidis into different locations of shell eggs and incubating inoculated eggs. These pathogen-containing eggs were heated at 57°C for 40 min, and temperature within eggs was monitored at the locations of inocula. Comparison of inactivation at equivalent internal temperatures revealed similar levels of lethality regardless of inoculum location. Refrigeration between incubation and heat treatment did not increase thermal resistance of cells in albumen but decreased cell inactivation in yolk. Sequential application of heat and gaseous ozone allows for the development of a process capable of decontaminating shell eggs with minimal thermal treatment and impact on egg quality. Inoculated eggs were subjected to (i) an immersion heating process similar to that used in commercial pasteurization or (ii) immersion heating, at reduced duration, followed by vacuum (50.8 kPa) and treatment with ozone gas (maximum 160 g/m(3)) under pressure (∼187.5 kPa). All treatments tested produced greater than 5-log inactivation, which is required for "pasteurization" processes. Differences were observed in the visual quality of eggs depending on treatment parameters. Application of ozone subsequent to heating allows for a significant reduction in heating time without decreasing process lethality.
Braun-Le Chatelier principle in dissipative thermodynamics
Pavelka, Michal
2016-01-01
Braun-Le Chatelier principle is a fundamental result of equilibrium thermodynamics, showing how stable equilibrium states shift when external conditions are varied. The principle follows from convexity of thermodynamic potential. Analogously, from convexity of dissipation potential it follows how steady non-equilibrium states shift when thermodynamic forces are varied, which is the extension of the principle to dissipative thermodynamics.
Foucault Dissipation in a Rolling Cylinder: A Webcam Quantitative Study
Bonanno, A.; Bozzo, G.; Camarca, M.; Sapia, P.
2011-01-01
In this paper we present an experimental strategy to measure the micro power dissipation due to Foucault "eddy" currents in a copper cylinder rolling on two parallel conductive rails in the presence of a magnetic field. Foucault power dissipation is obtained from kinematical measurements carried out by using a common PC webcam and video analysis…
Quantum dissipative effect of one dimension coupled anharmonic oscillator
Energy Technology Data Exchange (ETDEWEB)
Sulaiman, A. [Badan Pengkajian dan Penerapan Teknologi, BPPT Bld. II (19thfloor), Jl. M.H. Thamrin 8, Jakarta 10340 (Indonesia); Indonesia Center for Theoretical and Mathematical Physics (ICTMP), Jl. Ganesha 10, Bandung 40132 (Indonesia); Zen, Freddy P. [Theoretical Physics Laboratory (THEPI), Department of Physics, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Indonesia Center for Theoretical and Mathematical Physics (ICTMP), Jl. Ganesha 10, Bandung 40132 (Indonesia)
2015-04-16
Quantum dissipative effect of one dimension coupled anharmonic oscillator is investigated. The systems are two coupled harmonic oscillator with the different masses. The dissipative effect is studied based on the quantum state diffusion formalism. The result show that the anharmonic effect increase the amplitude but the lifetime of the oscillation depend on the damping coefficient and do not depend on the temperature.
Testing the Dissipative Type of a Qubit Interacting with Environment
Institute of Scientific and Technical Information of China (English)
曾浩生; 匡乐满; 高克林
2003-01-01
We propose a method to test the correctness of the coupling model of a qubit interacting with environment and to determine the type of dissipation. The environment is modelled by a bath of oscillators with infinite degrees of freedom and the qubit-bath coupling is chosen to be a general dissipation-decoherence form. The proposed method can be realized in current experiments.
Sufficient conditions for dissipativity on Duhem hysteresis model
Jayawardhana, B.; Andrieu, V.
2009-01-01
This paper presents sufficient conditions for dissipativity on the Duhem hysteresis model. The result of this paper describes the dissipativity property of several standard hysteresis models, including the backlash and Prandtl operator. It also allows the curve in the hysteresis diagram (the phase p
Dissipation and spontaneous symmetry breaking in brain dynamics
Freeman, Walter J
2008-01-01
We compare the predictions of the dissipative quantum model of brain with neurophysiological data collected from electroencephalograms resulting from high-density arrays fixed on the surfaces of primary sensory and limbic areas of trained rabbits and cats. Functional brain imaging in relation to behavior reveals the formation of coherent domains of synchronized neuronal oscillatory activity and phase transitions predicted by the dissipative model.
Refocusing schemes for holonomic quantum computation in presence of dissipation
Cen, Li-Xiang; Zanardi, Paolo
2004-01-01
The effects of dissipation on a holonomic quantum computation scheme are analyzed within the quantum-jump approach. We extend to the non-Abelian case the refocusing strategies formerly introduced for (Abelian) geometric computation. We show how double loop symmetrization schemes allow one to get rid of the unwanted influence of dissipation in the no-jump trajectory.
30 CFR 56.6602 - Static electricity dissipation during loading.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static electricity dissipation during loading... Explosives Extraneous Electricity § 56.6602 Static electricity dissipation during loading. When explosive material is loaded pneumatically into a blasthole in a manner that generates a static electricity...
30 CFR 57.6602 - Static electricity dissipation during loading.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static electricity dissipation during loading... MINES Explosives Extraneous Electricity-Surface and Underground § 57.6602 Static electricity dissipation... generates a static electricity hazard— (a) An evaluation of the potential static electricity hazard shall...
Dissipative quantum trajectories in complex space: Damped harmonic oscillator
Chou, Chia-Chun
2016-10-01
Dissipative quantum trajectories in complex space are investigated in the framework of the logarithmic nonlinear Schrödinger equation. The logarithmic nonlinear Schrödinger equation provides a phenomenological description for dissipative quantum systems. Substituting the wave function expressed in terms of the complex action into the complex-extended logarithmic nonlinear Schrödinger equation, we derive the complex quantum Hamilton-Jacobi equation including the dissipative potential. It is shown that dissipative quantum trajectories satisfy a quantum Newtonian equation of motion in complex space with a friction force. Exact dissipative complex quantum trajectories are analyzed for the wave and solitonlike solutions to the logarithmic nonlinear Schrödinger equation for the damped harmonic oscillator. These trajectories converge to the equilibrium position as time evolves. It is indicated that dissipative complex quantum trajectories for the wave and solitonlike solutions are identical to dissipative complex classical trajectories for the damped harmonic oscillator. This study develops a theoretical framework for dissipative quantum trajectories in complex space.
Dissipative Two-Level Spin System and Geometrical Phase
Cherbal, Omar; Drir, Mahrez
2006-01-01
We propose to extend the concept of geometric phase to quantum dissipative systems, in the case of meta-stable spin states in magnetic reso- nance. We use the generalized version of Lewis–Riensenfeld invariant theory to study the dissipative systems described by non-hermitian time-dependent Hamiltonian.
Hu, Yong; Wu, Feifei; Ma, Yongli; He, Jizhou; Wang, Jianhui; Hernández, A Calvo; Roco, J M M
2013-12-01
We study the coefficient of performance (COP) and its bounds for a Carnot-like refrigerator working between two heat reservoirs at constant temperatures T(h) and T(c), under two optimization criteria χ and Ω. In view of the fact that an "adiabatic" process usually takes finite time and is nonisentropic, the nonadiabatic dissipation and the finite time required for the adiabatic processes are taken into account by assuming low dissipation. For given optimization criteria, we find that the lower and upper bounds of the COP are the same as the corresponding ones obtained from the previous idealized models where any adiabatic process is undergone instantaneously with constant entropy. To describe some particular models with very fast adiabatic transitions, we also consider the influence of the nonadiabatic dissipation on the bounds of the COP, under the assumption that the irreversible entropy production in the adiabatic process is constant and independent of time. Our theoretical predictions match the observed COPs of real refrigerators more closely than the ones derived in the previous models, providing a strong argument in favor of our approach.
Earliest stages of the non-equilibrium in axially symmetric, self-gravitating, dissipative fluids
Herrera, L; Ospino, J; Carot, J
2016-01-01
We report a study on axially and reflection symmetric dissipative fluids, just after its departure from hydrostatic and thermal equilibrium, at the smallest time scale at which the first signs of dynamic evolution appear. Such a time scale is smaller than the thermal relaxation time, the thermal adjustment time and the hydrostatic time. It is obtained that the onset of non--equilibrium will critically depend on a single function directly related to the time derivative of the vorticity. Among all fluid variables (at the time scale under consideration), only the tetrad component of the anisotropic tensor in the subspace orthogonal to the four--velocity and the Killing vector of axial symmetry, shows signs of dynamic evolution. Also, the first step towards a dissipative regime begins with a non--vanishing time derivative of the heat flux component along the meridional direction. The magnetic part of the Weyl tensor vanishes (not so its time derivative), indicating that the emission of gravitational radiation wil...
Power dissipation in oxide-confined 980-nm vertical-cavity surface-emitting lasers
Institute of Scientific and Technical Information of China (English)
Shi Guo-Zhu; Guan Bao-Lu; Li Shuo; Wang Qiang; Shen Guang-Di
2013-01-01
We presented 980-nm oxide-confined vertical-cavity surface-emitting lasers (VCSELs) with a 16-μm oxide aperture.Optical power,voltage,and emission wavelength are measured in an ambient temperature range of 5 ℃-80 ℃.Measurements combined with an empirical model are used to analyse the power dissipation in the device and the physical mechanism contributing to the thermal rollover phenomenon in VCSEL.It is found that the carrier leakage induced self-heating in the active region and the Joule heating caused by the series resistance are the main sources of power dissipation.In addition,carrier leakage induced self-heating increases as the injection current increases,resulting in a rapid decrease of the internal quantum efficiency,which is a dominant contribution to the thermal rollover of the VCSEL at a larger current.Our study provides useful guidelines to design a 980-nm oxide-confined VCSEL for thermal performance enhancement.
Non-dissipative hydrodynamics: Effective actions versus entropy current
Bhattacharya, Jyotirmoy; Rangamani, Mukund
2012-01-01
While conventional hydrodynamics incorporating dissipative effects is hard to derive from an action principle, it is nevertheless possible to construct classical actions when the dissipative terms are switched off. In this note we undertake a systematic exploration of such constructions from an effective field theory approach and argue for the existence of non-trivial second order non-dissipative hydrodynamics involving pure energy-momentum transport. We find these fluids to be characterized by five second-order transport coefficients based on the effective action (a three parameter family is Weyl invariant). On the other hand since all flows of such fluids are non-dissipative, they entail zero entropy production; one can therefore understand them using the entropy current formalism which has provided much insight into hydrodynamic transport. An analysis of the most general stress tensor with zero entropy production however turns out to give a seven parameter family of non-dissipative hydrodynamics (a four pa...
Surveying the role of excitation energy in probing nuclear dissipation
Institute of Scientific and Technical Information of China (English)
YE Wei
2009-01-01
A dynamical Langevin model is employed to calculate the excess of the evaporation residue cross sections of the 194pb nucleus over that predicted by the standard statistical model as a function of nuclear dissipation strength. It is shown that large excitation energy can increase the effects of nuclear dissipation on the excess of the evaporation residues and the sensitivity of this excess to the dissipation strength, and that more higher excitation energies have little contribution to further raising this sensitivity. These results suggest that on the experimental side, producing those compound systems with moderate excitation energy is sufficient for a good determination of the pre-saddle nuclear dissipation strength by measuring the evaporation residue cross section, and that forming an extremely highly excited system does not considerably improve the sensitivity of evaporation residues to the dissipation strength.
Energy Dissipation in the Smagorinsky Model of Turbulence
Layton, William
2016-01-01
The Smagorinsky model, unmodified, is often reported to severely overdiffuse flows. Previous estimates of the energy dissipation rate of the Smagorinsky model for shear flows reflect a blow up of model energy dissipation as Re increases. This blow up is consistent with the numerical evidence and leads to the question: Is the over dissipation due to the influence of the turbulent viscosity in boundary layers alone or is its action on small scales generated by the nonlinearity through the cascade also a contributor? This report develops model dissipation estimates for body force driven flow under periodic boundary conditions (and thus only with nonlinearity generated small scales). It is proven that the model's time averaged energy dissipation rate satisfies the same upper bound as for the NSE plus one additional term that vanishes uniformly in the Reynolds number as the Smagorinsky length scale decreases. Since this estimate is consistent with that observed for the NSE, it establishes that, without boundary la...
Temporal intermittency of energy dissipation in magnetohydrodynamic turbulence.
Zhdankin, Vladimir; Uzdensky, Dmitri A; Boldyrev, Stanislav
2015-02-13
Energy dissipation in magnetohydrodynamic (MHD) turbulence is known to be highly intermittent in space, being concentrated in sheetlike coherent structures. Much less is known about intermittency in time, another fundamental aspect of turbulence which has great importance for observations of solar flares and other space or astrophysical phenomena. In this Letter, we investigate the temporal intermittency of energy dissipation in numerical simulations of MHD turbulence. We consider four-dimensional spatiotemporal structures, "flare events," responsible for a large fraction of the energy dissipation. We find that although the flare events are often highly complex, they exhibit robust power-law distributions and scaling relations. We find that the probability distribution of dissipated energy has a power-law index close to α≈1.75, similar to observations of solar flares, indicating that intense dissipative events dominate the heating of the system. We also discuss the temporal asymmetry of flare events as a signature of the turbulent cascade.
Is tendon stiffness correlated to the dissipation coefficient?
International Nuclear Information System (INIS)
The assessment of Achilles tendon mechanical properties in vivo has received much attention in the literature. Many studies investigated mechanical properties by assessing tendon stiffness. Despite tendon dissipative properties being representative of a storage-recoil process, its determination has received minimal attention in the literature. The aim of this study was to determine if Achilles tendon stiffness is associated with dissipative properties. The cross-sectional area, stiffness and dissipation coefficient of the Achilles tendon were measured in 35 subjects. No significant correlation was found between stiffness and the dissipation coefficient, irrespective of stiffness normalization with cross-sectional area (P > 0.05). Thus, it appears that both stiffness and dissipative properties must be assessed to determine the storage-recoil process capacities of the Achilles tendon in order to precisely characterize changes in the tendon mechanical properties after chronic interventions or rehabilitation programs. (note)
Tidal dissipation in rotating fluid bodies: a simplified model
Ogilvie, Gordon I
2009-01-01
We study the tidal forcing, propagation and dissipation of linear inertial waves in a rotating fluid body. The intentionally simplified model involves a perfectly rigid core surrounded by a deep ocean consisting of a homogeneous incompressible fluid. Centrifugal effects are neglected, but the Coriolis force is considered in full, and dissipation occurs through viscous or frictional forces. The dissipation rate exhibits a complicated dependence on the tidal frequency and generally increases with the size of the core. In certain intervals of frequency, efficient dissipation is found to occur even for very small values of the coefficient of viscosity or friction. We discuss the results with reference to wave attractors, critical latitudes and other features of the propagation of inertial waves within the fluid, and comment on their relevance for tidal dissipation in planets and stars.
Comparison of Energy Dissipation with and without Aerators
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Experimental results showed that aerators increase the energy dissipation of the flow in the channel by reducing the velocity coefficient φ in the deflector bucket and the jet-trajectory length, by increasing energy dissipation of the jet flow in the air and the diffusion length of the jet falling into the pool and by reducing the energy intensity of the jet falling into the pool. The energy dissipation prevents wash out downstream.When air is not entrained in the water flow, the aerators act as artificial irregularities in the channel. The energy dissipation due to the aerators in the channel without entrained air is greater than when air is entrained in the water flow.Correlations of the experimental data can be used to estimate the energy dissipation effect of the aerators on the outlet structure for the three test cases.
Temporal Intermittency of Energy Dissipation in Magnetohydrodynamic Turbulence
Zhdankin, Vladimir; Boldyrev, Stanislav
2015-01-01
Energy dissipation in magnetohydrodynamic (MHD) turbulence is known to be highly intermittent in space, being concentrated in sheet-like coherent structures. Much less is known about intermittency in time, another fundamental aspect of turbulence which has great importance for observations of solar flares and other space/astrophysical phenomena. In this Letter, we investigate the temporal intermittency of energy dissipation in numerical simulations of MHD turbulence. We consider four-dimensional spatiotemporal structures, "flare events", responsible for a large fraction of the energy dissipation. We find that although the flare events are often highly complex, they exhibit robust power-law distributions and scaling relations. We find that the probability distribution of dissipated energy has a power law index close to -1.75, similar to observations of solar flares, indicating that intense dissipative events dominate the heating of the system. We also discuss the temporal asymmetry of flare events as a signatu...
Dissipation gradients of phenanthrene and pyrene in the Rice rhizosphere
International Nuclear Information System (INIS)
An experiment was conducted to reveal the effects of rice cultivation as well as polycyclic aromatic carbohydrates (PAHs) degrading bacterium (Acinetobacter sp.) on the dissipation gradients of two PAHs (PHE and PYR) in the rhizosphere. The results showed that the presence of rice root and bacteria significantly accelerated the dissipation rate of PHE and PYR. The root exudates contributed to the formation of dissipation gradients of PHE and PYR along the vertical direction of roots, with a higher dissipation rate in the rhizosphere and near rhizosphere zone than the soil far away the rhizosphere. - The formation of dissipation gradients of PAHs were attributed to the presence of rice root and the degrading bacteria in paddy soil.
煤价变动对火电厂发电运行成本的影响%Changes Affect the Cost of Thermal Power Generation Coal Operation
Institute of Scientific and Technical Information of China (English)
邵艳丽
2014-01-01
对当前我国火力发电厂发电运行成本不断上涨的原因进行了阐述，分析了煤炭价格的变化对火电厂发电运行成本的影响，提出了火力发电厂应对煤价变动的一些参考策略，希望能为广大火电厂的节能减排、利益最大化提供一些参考。%The reasons for the current operating costs of thermal power generation rising are described, analyzed the impact of changes in the price of coal fire power plant operating costs, proposed changes in the price of coal power plant deal with some reference strategy, hoping to for the majority of thermal power plant of energy conservation, to provide some reference to maximize benefits.
Quantum properties of a single-mode dissipative amplifier against Schroedinger-cat states
International Nuclear Information System (INIS)
In this paper we investigate the single-mode properties (Wigner function, photon-number distribution and quadrature squeezing) of a dissipative parametric amplifier when the signal and idler modes are initially prepared in the Schroedinger-cat states. We show that there are two sources producing decoherence in the system, which are spontaneous pump photon decay and interaction with the environment. For the latter case, the system collapses to both statistical mixture states as well as thermal states governed by the interaction parameters
International Nuclear Information System (INIS)
We study the effects of dissipation and decoherence induced on a harmonic oscillator by the coupling to a chaotic system with two degrees of freedom. Using the Feynman-Vernon approach and treating the chaotic system semiclassically, we show that the effects of the low-dimensional chaotic environment are in many ways similar to those produced by thermal baths. The classical correlation and response functions play important roles in both classical and quantum formulations. Our results are qualitatively similar to the high-temperature regime of the Caldeira-Leggett model
Quantified Energy Dissipation Rates in the Terrestrial Bow Shock. 2; Waves and Dissipation
Wilson, L. B., III; Sibeck, D. G.; Breneman, A. W.; Le Contel, O.; Cully, C.; Turner, D. L.; Angelopoulos, V.; Malaspina, D. M.
2014-01-01
We present the first quantified measure of the energy dissipation rates, due to wave-particle interactions, in the transition region of the Earth's collision-less bow shock using data from the Time History of Events and Macro-Scale Interactions during Sub-Storms spacecraft. Our results show that wave-particle interactions can regulate the global structure and dominate the energy dissipation of collision-less shocks. In every bow shock crossing examined, we observed both low-frequency (less than 10 hertz) and high-frequency (approximately or greater than10 hertz) electromagnetic waves throughout the entire transition region and into the magnetosheath. The low-frequency waves were consistent with magnetosonic-whistler waves. The high-frequency waves were combinations of ion-acoustic waves, electron cyclotron drift instability driven waves, electrostatic solitary waves, and whistler mode waves. The high-frequency waves had the following: (1) peak amplitudes exceeding delta B approximately equal to 10 nanoteslas and delta E approximately equal to 300 millivolts per meter, though more typical values were delta B approximately equal to 0.1-1.0 nanoteslas and delta E approximately equal to 10-50 millivolts per meter (2) Poynting fluxes in excess of 2000 microWm(sup -2) (micro-waves per square meter) (typical values were approximately 1-10 microWm(sup -2) (micro-waves per square meter); (3) resistivities greater than 9000 omega meters; and (4) associated energy dissipation rates greater than 10 microWm(sup -3) (micro-waves per cubic meter). The dissipation rates due to wave-particle interactions exceeded rates necessary to explain the increase in entropy across the shock ramps for approximately 90 percent of the wave burst durations. For approximately 22 percent of these times, the wave-particle interactions needed to only be less than or equal to 0.1 percent efficient to balance the nonlinear wave steepening that produced the shock waves. These results show that wave
Relaxation Time and Dissipation Interaction in Hot Planet Atmospheric Flow Simulations
Thrastarson, Heidar Thor
2010-01-01
We elucidate the interplay between Newtonian thermal relaxation and numerical dissipation, of several different origins, in flow simulations of hot extrasolar planet atmospheres. Currently, a large range of Newtonian relaxation, or "cooling", times (~10 days to ~1 hour) is used among different models and within a single model over the model domain. In this study we demonstrate that a short relaxation time (much less than the planetary rotation time) leads to a large amount of unphysical, grid-scale oscillations that contaminate the flow field. These oscillations force the use of an excessive amount of artificial viscosity to quench them and prevent the simulation from "blowing up". Even if the blow-up is prevented, such simulations can be highly inaccurate because they are either severely over-dissipated or under-dissipated, and are best discarded in these cases. Other numerical stability and timestep size enhancers (e.g., Robert-Asselin filter or semi-implicit time-marching schemes) also produce similar, but...
Efficiency at and near maximum power of low-dissipation heat engines
Holubec, Viktor; Ryabov, Artem
2015-11-01
A universality in optimization of trade-off between power and efficiency for low-dissipation Carnot cycles is presented. It is shown that any trade-off measure expressible in terms of efficiency and the ratio of power to its maximum value can be optimized independently of most details of the dynamics and of the coupling to thermal reservoirs. The result is demonstrated on two specific trade-off measures. The first one is designed for finding optimal efficiency for a given output power and clearly reveals diseconomy of engines working at maximum power. As the second example we derive universal lower and upper bounds on the efficiency at maximum trade-off given by the product of power and efficiency. The results are illustrated on a model of a diffusion-based heat engine. Such engines operate in the low-dissipation regime given that the used driving minimizes the work dissipated during the isothermal branches. The peculiarities of the corresponding optimization procedure are reviewed and thoroughly discussed.
Efficiency at and near maximum power of low-dissipation heat engines.
Holubec, Viktor; Ryabov, Artem
2015-11-01
A universality in optimization of trade-off between power and efficiency for low-dissipation Carnot cycles is presented. It is shown that any trade-off measure expressible in terms of efficiency and the ratio of power to its maximum value can be optimized independently of most details of the dynamics and of the coupling to thermal reservoirs. The result is demonstrated on two specific trade-off measures. The first one is designed for finding optimal efficiency for a given output power and clearly reveals diseconomy of engines working at maximum power. As the second example we derive universal lower and upper bounds on the efficiency at maximum trade-off given by the product of power and efficiency. The results are illustrated on a model of a diffusion-based heat engine. Such engines operate in the low-dissipation regime given that the used driving minimizes the work dissipated during the isothermal branches. The peculiarities of the corresponding optimization procedure are reviewed and thoroughly discussed. PMID:26651665
Efficiency at and near maximum power of low-dissipation heat engines.
Holubec, Viktor; Ryabov, Artem
2015-11-01
A universality in optimization of trade-off between power and efficiency for low-dissipation Carnot cycles is presented. It is shown that any trade-off measure expressible in terms of efficiency and the ratio of power to its maximum value can be optimized independently of most details of the dynamics and of the coupling to thermal reservoirs. The result is demonstrated on two specific trade-off measures. The first one is designed for finding optimal efficiency for a given output power and clearly reveals diseconomy of engines working at maximum power. As the second example we derive universal lower and upper bounds on the efficiency at maximum trade-off given by the product of power and efficiency. The results are illustrated on a model of a diffusion-based heat engine. Such engines operate in the low-dissipation regime given that the used driving minimizes the work dissipated during the isothermal branches. The peculiarities of the corresponding optimization procedure are reviewed and thoroughly discussed.
Research on the Heat Dissipation Characteristics of Lithium Battery Spatial Layout in an AUV
Directory of Open Access Journals (Sweden)
Zhaoyong Mao
2016-01-01
Full Text Available To meet the power demand requirements of autonomous underwater vehicles (AUVs, the power supply is generally composed of a large number of high-energy lithium battery groups. The lithium battery heat dissipation properties not only affect the underwater vehicle performance but also bring some security risks. Based on the widespread application of lithium batteries, lithium batteries in an AUV are taken as an example to investigate the heat dissipation characteristics of the lithium battery spatial layout in an AUV. With the aim of increasing the safety of lithium batteries, a model is developed for the heat transfer process based on the energy conservation equation, and the battery heat dissipation characteristics of the spatial layout are analyzed. The results indicate that the most suitable distance between the cells and the cross arrangement is better than the sequence arrangement in terms of cooling characteristics. The temperature gradient and the temperature change inside the cabin with time are primarily affected by the navigation speed, but they have little relationship with the environmental temperature.
Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator
Directory of Open Access Journals (Sweden)
Bimlesh Kumar
2009-12-01
Full Text Available mixing in surface aerators. At constant dynamic variables (rotational speed, both and γ are greatly affected by the geometric parameters (impeller diameter, cross-sectional area of the tank, liquid height, rotor blade length and immersion height. By doing numerical computation by VISIMIX ®, present work analyzes the effect of non-dimensional (which is non-dimensionalized through rotor diameter geometric parameters on e and g. With an increase in liquid height, there is an increase in the case of energy dissipation and shear rate values. In the case of tank area and blade length, it is vice versa. Energy dissipation and shear rate are not affected by the variation in immersion height of the impeller. © 2009 BCREC UNDIP. All rights reserved[Received: 17 October 2009, Revised: 12 December 2009, Accepted: 20 December 2009][How to Cite: B. Kumar. (2009. Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator. Bulletin of Chemical Reaction Engineering and Catalysis, 4(2: 55-60. doi:10.9767/bcrec.4.2.30.55-60][How to Link/ DOI: http://dx.doi.org/10.9767/bcrec.4.2.30.55-60
Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator
Directory of Open Access Journals (Sweden)
Bimlesh Kumar
2009-12-01
Full Text Available mixing in surface aerators. At constant dynamic variables (rotational speed, both and γ are greatly affected by the geometric parameters (impeller diameter, cross-sectional area of the tank, liquid height, rotor blade length and immersion height. By doing numerical computation by VISIMIX ®, present work analyzes the effect of non-dimensional (which is non-dimensionalized through rotor diameter geometric parameters on e and g. With an increase in liquid height, there is an increase in the case of energy dissipation and shear rate values. In the case of tank area and blade length, it is vice versa. Energy dissipation and shear rate are not affected by the variation in immersion height of the impeller. © 2009 BCREC UNDIP. All rights reserved[Received: 17 October 2009, Revised: 12 December 2009, Accepted: 20 December 2009][How to Cite: B. Kumar. (2009. Variability of Energy Dissipation and Shear Rate with Geometry in Unbaffled Surface Aerator. Bulletin of Chemical Reaction Engineering and Catalysis, 4(2: 55-60. doi:10.9767/bcrec.4.2.7110.55-60][How to Link/ DOI: http://dx.doi.org/10.9767/bcrec.4.2.7110.55-60 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/7110
Liu, Peng; Fan, Zeng; Mikhalchan, Anastasiia; Tran, Thang Q; Jewell, Daniel; Duong, Hai M; Marconnet, Amy M
2016-07-13
The production of continuous carbon nanotube (CNT) fibers and films has paved the way to leverage the superior properties of individual carbon nanotubes for novel macroscale applications such as electronic cables and multifunctional composites. In this manuscript, we synthesize fibers and films from CNT aerogels that are continuously grown by floating catalyst chemical vapor deposition (FCCVD) and measure thermal conductivity and natural convective heat transfer coefficient from the fiber and film. To probe the mechanisms of heat transfer, we develop a new, robust, steady-state thermal characterization technique that enables measurement of the intrinsic fiber thermal conductivity and the convective heat transfer coefficient from the fiber to the surrounding air. The thermal conductivity of the as-prepared fiber ranges from 4.7 ± 0.3 to 28.0 ± 2.4 W m(-1) K(-1) and depends on fiber volume fraction and diameter. A simple nitric acid treatment increases the thermal conductivity by as much as a factor of ∼3 for the fibers and ∼6.7 for the thin films. These acid-treated CNT materials demonstrate specific thermal conductivities significantly higher than common metals with the same absolute thermal conductivity, which means they are comparatively lightweight, thermally conductive fibers and films. Beyond thermal conductivity, the acid treatment enhances electrical conductivity by a factor of ∼2.3. Further, the measured convective heat transfer coefficients range from 25 to 200 W m(-2) K(-1) for all fibers, which is higher than expected for macroscale materials and demonstrates the impact of the nanoscale CNT features on convective heat losses from the fibers. The measured thermal and electrical performance demonstrates the promise for using these fibers and films in macroscale applications requiring effective heat dissipation. PMID:27322344
International Nuclear Information System (INIS)
The studies on the magnetic characteristics of the 12Kh1M1F heat resistant steel are carried out in the zones of melting and thermal effect by different modes of the electric are welding and the new approach to calculating and forecasting the longevity of service of the steam pipe welded joints is proposed on the basis of the magnetic structuroscopy. The local step-by-step (with the 1-2 mm interval) measurement of the metal residual magnetization after magnetization through the point pole method is accomplished in the welded joint area after the removal of the weld reinforcement. The evaluating of the welding modes violations and the joint longevity forecast are given in the basis of the maximum and minimum measurement results or their distribution along the measurement line
Energy Technology Data Exchange (ETDEWEB)
Medina, C.; Tiesler, V. [Universidad Autonoma de Yucatan, Facultad de Ciencias Antropoloicas. 97000 Merida, Yucatan (Mexico); Azamar, J.A.; Alvarado G, J.J.; Quintana, P. [CINVESTAV-Unidad Merida, Depto. Fisica Aplicada, Km 6 Ant. Carr. a Progreso, 97310 Merida, Yucatan (Mexico)
2006-07-01
Bone is made up by both organic and inorganic components. Among the latter stands out hydroxyapatite (HAP), composed by hexagonal crystallites arranged in a laminar form. The size of the hydroxyapatite crystals may be altered by different conditions, among those figures thermal exhibition, since during burning the bone eliminates organic matrix and thus promotes the crystallization process of the material. An experimental series was designed to measure crystallinity, in which pig bone remains were burnt at different temperatures and analyzed by infrared spectroscopy (FTIR). By means of analogy a comparison was made between the infrared spectra in order to compare with the ones obtained from the archaeological samples, coming from the Classic period Maya sites of Calakmul and Becan, Campeche. (Author)
Recovery curves of the lightning discharges occurring in the dissipation stage of thunderstorms
Indian Academy of Sciences (India)
S D Pawar; A K Kamra
2013-04-01
Measurements of atmospheric electric field made below two thunderstorms show that all lightning discharges occurring in the dissipating stage of a thunderstorm occur at almost the same value of the predischarge electric field at the ground surface. The observation is explained on the basis of the shielding of the electric fields generated by the positive charge in the downdrafts by the negative charge in the screening layers formed around them in the subcloud layer. Our observations suggest that in the dissipating stage of the thunderstorm, the charge generating mechanisms in cloud have ceased to operate and the charge being transported from the upper to lower regions of cloud by downdrafts is the only in-cloud process affecting the surface electric field and/or enhancing the electric field stress in and below the cloud base to cause yet another lightning discharge.
Fernández-Cruz, María L; Barreda, Mercedes; Villarroya, Mercedes; Peruga, Arantzazu; Llanos, Susana; García-Baudín, José M
2006-07-01
Field trial studies have been performed with captan and fenitrothion on cauliflower to propose maximum residue limits and to study the dissipation of the pesticides. Residue levels have been determined at different times following good laboratory practice using gas chromatography with mass spectrometric detection. The behaviour of residue levels of these compounds after household processing has been analysed using gas chromatography with electron capture detection. Seven days after treatment, residue levels of captan could be detected, but not of fenitrothion. The half-lives of dissipation for captan and fenitrothion were calculated as 0.9 and 1.8 days respectively. Washing did not significantly affect the residual amounts of captan and fenitrothion observed in raw vegetables; however, after cooking, captan had degraded completely, whereas residue levels of fenitrothion were not modified significantly.
Thermal conductivity of silicon nitride membranes is not sensitive to stress
Ftouni, Hossein; Blanc, Christophe; Tainoff, Dimitri; Fefferman, Andrew D.; Defoort, Martial; Lulla, Kunal J.; Richard, Jacques; Collin, Eddy; Bourgeois, Olivier
2015-09-01
We have measured the thermal properties of suspended membranes from 10 to 300 K for two amplitudes of internal stress (about 0.1 and 1 GPa) and for two different thicknesses (50 and 100 nm). The use of the original 3 ω -Volklein method has allowed the extraction of both the specific heat and the thermal conductivity of each SiN membrane over a wide temperature range. The mechanical properties of the same substrates have been measured at helium temperatures using nanomechanical techniques. Our measurements show that the thermal transport in freestanding SiN membranes is not affected by the presence of internal stress. Consistently, mechanical dissipation is also unaffected even though Q 's increase with increasing tensile stress. We thus demonstrate that the theory developed by Wu and Yu [J. Wu and C. C. Yu, Phys. Rev. B 84, 174109 (2011), 10.1103/PhysRevB.84.174109] does not apply to this amorphous material in this stress range. On the other hand, our results can be viewed as a natural consequence of the "dissipation dilution" argument [Y. L. Huang and P. R. Saulson, Rev. Sci. Instrum. 69, 544 (1998), 10.1063/1.1148692], which has been introduced in the context of mechanical damping.
Skin histology and its role in heat dissipation in three pinniped species
Directory of Open Access Journals (Sweden)
Khamas Wael A
2012-08-01
Full Text Available Abstract Background Pinnipeds have a thick blubber layer and may have difficulty maintaining their body temperature during hot weather when on land. The skin is the main thermoregulatory conduit which emits excessive body heat. Methods Thorough evaluation of the skin histology in three pinniped species; the California sea lion-Zalophus californianus, the Pacific harbor seal-Phoca vitulina richardsi, and the Northern elephant seal-Mirounga angustirostris, was conducted to identify the presence, location and distribution of skin structures which contribute to thermoregulation. These structures included hair, adipose tissue, sweat glands, vasculature, and arteriovenous anastomoses (AVA. Thermal imaging was performed on live animals of the same species to correlate histological findings with thermal emission of the skin. Results The presence and distribution of skin structures directly relates to emissivity of the skin in all three species. Emissivity of skin in phocids (Pacific harbor and Northern elephant seals follows a different pattern than skin in otariids (California sea lions. The flipper skin in phocids tends to be the most emissive region during hot weather and least emissive during cold weather. On the contrary in otariids, skin of the entire body has a tendency to be emissive during both hot and cold weather. Conclusion Heat dissipation of the skin directly relates to the presence and distribution of skin structures in all three species. Different skin thermal dissipation patterns were observed in phocid versus otariid seals. Observed thermal patterns can be used for proper understanding of optimum thermal needs of seals housed in research facilities, rescue centers and zoo exhibits.
Phonon-mediated heat dissipation in a monatomic lattice: case study on Ni
Levchenko, Elena V.; Evteev, Alexander V.; Momenzadeh, Leila; Belova, Irina V.; Murch, Graeme E.
2015-11-01
The recently introduced analytical model for the heat current autocorrelation function of a crystal with a monatomic lattice [Evteev et al., Phil. Mag. 94 (2014) p. 731 and 94 (2014) p. 3992] is employed in conjunction with the Green-Kubo formalism to investigate in detail the results of an equilibrium molecular dynamics calculations of the temperature dependence of the lattice thermal conductivity and phonon dynamics in f.c.c. Ni. Only the contribution to the lattice thermal conductivity determined by the phonon-phonon scattering processes is considered, while the contribution due to phonon-electron scattering processes is intentionally ignored. Nonetheless, during comparison of our data with experiment an estimation of the second contribution is made. Furthermore, by comparing the results obtained for f.c.c. Ni model to those for other models of elemental crystals with the f.c.c. lattice, we give an estimation of the scaling relations of the lattice thermal conductivity with other lattice properties such as the coefficient of thermal expansion and the bulk modulus. Moreover, within the framework of linear response theory and the fluctuation-dissipation theorem, we extend our analysis in this paper into the frequency domain to predict the power spectra of equilibrium fluctuations associated with the phonon-mediated heat dissipation in a monatomic lattice. The practical importance of the analytical treatment lies in the fact that it has the potential to be used in the future to efficiently decode the generic information on the lattice thermal conductivity and phonon dynamics from a power spectrum of the acoustic excitations in a monatomic crystal measured by a spectroscopic technique in the frequency range of about 1-20 THz.
Time course of sleep inertia dissipation in human performance and alertness
Jewett, M. E.; Wyatt, J. K.; Ritz-De Cecco, A.; Khalsa, S. B.; Dijk, D. J.; Czeisler, C. A.
1999-01-01
Alertness and performance on a wide variety of tasks are impaired immediately upon waking from sleep due to sleep inertia, which has been found to dissipate in an asymptotic manner following waketime. It has been suggested that behavioural or environmental factors, as well as sleep stage at awakening, may affect the severity of sleep inertia. In order to determine the time course of sleep inertia dissipation under normal entrained conditions, subjective alertness and cognitive throughput were measured during the first 4 h after habitual waketime from a full 8-h sleep episode on 3 consecutive days. We investigated whether this time course was affected by either sleep stage at awakening or behavioural/environmental factors. Sleep inertia dissipated in an asymptotic manner and took 2-4 h to near the asymptote. Saturating exponential functions fitted the sleep inertia data well, with time constants of 0.67 h for subjective alertness and 1.17 h for cognitive performance. Most awakenings occurred out of stage rapid eye movement (REM), 2 or 1 sleep, and no effect of sleep stage at awakening on either the severity of sleep inertia or the time course of its dissipation could be detected. Subjective alertness and cognitive throughput were significantly impaired upon awakening regardless of whether subjects got out of bed, ate breakfast, showered and were exposed to ordinary indoor room light (approximately 150 lux) or whether subjects participated in a constant routine (CR) protocol in which they remained in bed, ate small hourly snacks and were exposed to very dim light (10-15 lux). These findings allow for the refinement of models of alertness and performance, and have important implications for the scheduling of work immediately upon awakening in many occupational settings.
Chakravarthy, Sunada; Gonthier, Keith A.
2016-07-01
Variations in the microstructure of granular explosives (i.e., particle packing density, size, shape, and composition) can affect their shock sensitivity by altering thermomechanical fields at the particle-scale during pore collapse within shocks. If the deformation rate is fast, hot-spots can form, ignite, and interact, resulting in burn at the macro-scale. In this study, a two-dimensional finite and discrete element technique is used to simulate and examine shock-induced dissipation and hot-spot formation within low density explosives (68%-84% theoretical maximum density (TMD)) consisting of large ensembles of HMX (C4H8N8O8) and aluminum (Al) particles (size ˜ 60 -360 μm). Emphasis is placed on identifying how the inclusion of Al influences effective shock dissipation and hot-spot fields relative to equivalent ensembles of neat/pure HMX for shocks that are sufficiently strong to eliminate porosity. Spatially distributed hot-spot fields are characterized by their number density and area fraction enabling their dynamics to be described in terms of nucleation, growth, and agglomeration-dominated phases with increasing shock strength. For fixed shock particle speed, predictions indicate that decreasing packing density enhances shock dissipation and hot-spot formation, and that the inclusion of Al increases dissipation relative to neat HMX by pressure enhanced compaction resulting in fewer but larger HMX hot-spots. Ensembles having bimodal particle sizes are shown to significantly affect hot-spot dynamics by altering the spatial distribution of hot-spots behind shocks.
Scaling laws for the upper ocean temperature dissipation rate
Bogucki, Darek J.; Huguenard, K.; Haus, B. K.; Özgökmen, T. M.; Reniers, A.; Laxague, N. J. M.
2015-02-01
Our understanding of temperature dissipation rate χ within the upper ocean boundary layer, which is critical for climate forecasts, is very limited. Near-surface turbulence also affects dispersion of contaminants and biogeochemical tracers. Using high-resolution optical turbulence measurements, scaling laws for χ are investigated under forcing states where either the daytime heat flux or the wind stress forcing is dominant. We find that χ remains constant over 1.5 times the significant wave height, while over a layer below, χ decays based on the local surface forcing. When the heat flux is dominant, traditional scaling based on the Monin-Obukhov similarity theory remains valid; χ ∝ z-1. When the wind stress dominates, we observe the emergence of a new scaling, χ ∝ z-1/2, which is explained by invoking the effect of small-scale coherent structures on vertical heat transport. These results have implications for improved modeling of the ocean's heat and CO2 intake.
Energy dissipation of rockfalls by coppice structures
Ciabocco, G.; Boccia, L.; Ripa, M. N.
2009-06-01
The objective of this work is to develop elements to improve understanding of the behaviour of a coppice in relation to the phenomenon of falling boulders. The first section proposes an amendment to the equation for calculating the index which describes the probability of impact between a rock and plants in managed coppice forests. A study was carried out, using models to calculate the kinetic energy of a falling boulder along a slope considering the kinetic energy dissipated during the impact with the structure of forest plants managed by coppice. The output of the simulation models were then compared with the real dynamics of falling boulders in field tests using digital video. It emerged from an analysis of the results of this comparison that a modification to the 1989 Gsteiger equation was required, in order to calculate the "Average Distance between Contacts" (ADC). To this purpose, the concept of "Structure of Interception", proposed in this paper, was developed, valid as a first approach for describing the differences in the spatial distribution of stems between coppice and forest. This study also aims to provide suggestions for forestry management, in order to maintain or increase the protective capacity of a coppice managed with conventional techniques for the area studied, modifying the dendrometric characteristics.
Energy dissipation of rockfalls by coppice structures
Directory of Open Access Journals (Sweden)
G. Ciabocco
2009-06-01
Full Text Available The objective of this work is to develop elements to improve understanding of the behaviour of a coppice in relation to the phenomenon of falling boulders. The first section proposes an amendment to the equation for calculating the index which describes the probability of impact between a rock and plants in managed coppice forests. A study was carried out, using models to calculate the kinetic energy of a falling boulder along a slope considering the kinetic energy dissipated during the impact with the structure of forest plants managed by coppice. The output of the simulation models were then compared with the real dynamics of falling boulders in field tests using digital video.
It emerged from an analysis of the results of this comparison that a modification to the 1989 Gsteiger equation was required, in order to calculate the "Average Distance between Contacts" (ADC. To this purpose, the concept of "Structure of Interception", proposed in this paper, was developed, valid as a first approach for describing the differences in the spatial distribution of stems between coppice and forest. This study also aims to provide suggestions for forestry management, in order to maintain or increase the protective capacity of a coppice managed with conventional techniques for the area studied, modifying the dendrometric characteristics.
Minimum-dissipation models for large-eddy simulation
Bae, Hyunji Jane; Rozema, Wybe; Moin, Parviz; Verstappen, Roel
2015-11-01
Minimum-dissipation eddy-viscosity models are a class of subgrid scale models for LES that give the minimum eddy dissipation required to dissipate the energy of subgrid scales. The QR minimum-dissipation model [Verstappen, J. Sci. Comp., 2011] gives good results in simulations of decaying grid turbulence carried out on an isotropic grid. In particular, due to the minimum dissipation property of the model, the predicted energy spectra are in very good agreement with the DNS results up to the cut-off wave number unlike other methods. However, its results on anisotropic grids are often unsatisfactory because the model does not properly incorporate the grid anisotropy. We propose the anisotropic minimum-dissipation (AMD) model [Rozema et al., submitted for publication, 2015], a minimum-dissipation model that generalizes the QR model to anisotropic grids. The AMD model is more cost effective than the dynamic Smagorinsky model, appropriately switches off in laminar and transitional flow on anisotropic grids, and its subgrid scale model is consistent with the theoretic subgrid tensor. Experiments show that the AMD model is as accurate as the dynamic Smagorinsky model and Vreman model in simulations of isotropic turbulence, temporal mixing layer, and turbulent channel flow. H. J. Bae acknowledges support from SGF. W. Rozema and R. Verstappen acknowledge sponsoring by NWO for the use of supercomputing facilities and the financial support to attend the CTR SP 2014.
Global Regularity for Several Incompressible Fluid Models with Partial Dissipation
Wu, Jiahong; Xu, Xiaojing; Ye, Zhuan
2016-09-01
This paper examines the global regularity problem on several 2D incompressible fluid models with partial dissipation. They are the surface quasi-geostrophic (SQG) equation, the 2D Euler equation and the 2D Boussinesq equations. These are well-known models in fluid mechanics and geophysics. The fundamental issue of whether or not they are globally well-posed has attracted enormous attention. The corresponding models with partial dissipation may arise in physical circumstances when the dissipation varies in different directions. We show that the SQG equation with either horizontal or vertical dissipation always has global solutions. This is in sharp contrast with the inviscid SQG equation for which the global regularity problem remains outstandingly open. Although the 2D Euler is globally well-posed for sufficiently smooth data, the associated equations with partial dissipation no longer conserve the vorticity and the global regularity is not trivial. We are able to prove the global regularity for two partially dissipated Euler equations. Several global bounds are also obtained for a partially dissipated Boussinesq system.
A dimensionless model of impact piezoelectric energy harvesting with dissipation
Fu, Xinlei; Liao, Wei-Hsin
2016-04-01
Impact excitation is common in the environment. Impact piezoelectric energy harvesting could realize frequency up-conversion. However, the dissipation mechanism in impact piezoelectric energy harvesting has not been investigated so far. There is no comprehensive model to be able to analyze the impact piezoelectric energy harvesting thoroughly. This paper is aimed to develop a generalized model that considers dissipation mechanism of impact piezoelectric energy harvesting. In this electromechanical model, Hertzian contact theory and impact dissipation mechanism are identified as constitutive mechanisms. The impact force is compared and the energy distribution is analyzed so that input energy corresponds to impact dissipated energy, structural damping dissipated energy and harvested electrical energy. We then nondimensionalize the developed model and define five dimensionless parameters with attributed physical meanings, including dimensionless parameters of impact dissipation, mass ratio, structural damping, electromechanical coupling, and electrical load. We conclude it is more accurate to consider impact dissipation mechanism to predict impact force and harvested energy. The guideline for improving harvested energy based on parametric studies of dimensionless model is to increase mass ratio, to minimize structural damping, to maximize electromechanical coupling, to use optimal load resistance for impedance matching, and to choose proper impact velocity .
Identification of energy dissipation mechanisms in CNT-reinforced nanocomposites
Gardea, Frank; Glaz, Bryan; Riddick, Jaret; Lagoudas, Dimitris C.; Naraghi, Mohammad
2016-03-01
In this paper we present our recent findings on the mechanisms of energy dissipation in polymer-based nanocomposites obtained through experimental investigations. The matrix of the nanocomposite was polystyrene (PS) which was reinforced with carbon nanotubes (CNTs). To study the mechanical strain energy dissipation of nanocomposites, we measured the ratio of loss to storage modulus for different CNT concentrations and alignments. CNT alignment was achieved via hot-drawing of PS-CNT. In addition, CNT agglomeration was studied via a combination of SEM imaging and Raman scanning. We found that at sufficiently low strains, energy dissipation in composites with high CNT alignment is not a function of applied strain, as no interfacial slip occurs between the CNTs and PS. However, below the interfacial slip strain threshold, damping scales monotonically with CNT content, which indicates the prevalence of CNT-CNT friction dissipation mechanisms within agglomerates. At higher strains, interfacial slip also contributes to energy dissipation. However, the increase in damping with strain, especially when CNT agglomerates are present, does not scale linearly with the effective interface area between CNTs and PS, suggesting a significant contribution of friction between CNTs within agglomerates to energy dissipation at large strains. In addition, for the first time, a comparison between the energy dissipation in randomly oriented and aligned CNT composites was made. It is inferred that matrix plasticity and tearing caused by misorientation of CNTs with the loading direction is a major cause of energy dissipation. The results of our research can be used to design composites with high energy dissipation capability, especially for applications where dynamic loading may compromise structural stability and functionality, such as rotary wing structures and antennas.
Aranguren, P.; Astrain, D.; Martínez, A.
2014-06-01
Reduction of the thermal resistances of the heat exchangers of a thermoelectric generation (TEG) system leads to a significant increase in TEG efficiency. For the cold side of a thermoelectric module (TEM), a wide range of heat exchangers have been studied, from simple finned dissipators to more complex water (water-glycol) heat exchangers. As the Nusselt number is much higher in water heat exchangers than in conventional air finned dissipators, the convective thermal resistances are better. However, to conclude which heat exchanger leads to higher efficiencies, it is necessary to include the whole system involved in the heat dissipation, i.e., the TEM-to-water heat exchanger, the water-to-ambient heat exchanger, as well as the required pumps and fans. This paper presents a dynamic computational model able to simulate the complete behavior of a TEG, including both heat exchangers. The model uses the heat transfer and hydraulic equations to compute the TEM-to-water and water-to-ambient thermal resistances, along with the resistance of the hot-side heat exchanger at different operating conditions. Likewise, the model includes all the thermoelectric effects with temperature-dependent properties. The model calculates the net power generation for different configurations, providing a methodology to design and optimize the heat exchange in order to maximize the net power generation for a wide variety of TEGs.
Quantum tunneling in thermal medium
Matsumoto, Sh.; Yoshimura, M.
2000-01-01
Time evolution of tunneling phenomena in medium is studied using a standard model of environment interaction. A semiclassical formula valid at low, but finite temperatures is derived in the form of integral transform for the reduced Wigner function, and the tunneling probability in thermal medium is calculated for a general tunneling potential of one dimensional system. Effect of dissipation, its time evolution in particular, depends on the behavior of the potential far beyond the barrier.
Short-pulse dynamics in strongly nonlinear dissipative granular chains.
Rosas, Alexandre; Romero, Aldo H; Nesterenko, Vitali F; Lindenberg, Katja
2008-11-01
We study the energy decay properties of a pulse propagating in a strongly nonlinear granular chain with damping proportional to the relative velocity of the grains. We observe a wave disturbance that at low viscosities consists of two parts exhibiting two entirely different time scales of dissipation. One part is an attenuating solitary wave, dominated by discreteness and nonlinearity effects as in a dissipationless chain, and has the shorter lifetime. The other is a purely dissipative shocklike structure with a much longer lifetime and exists only in the presence of dissipation. The range of viscosities and initial configurations that lead to this complex wave disturbance are explored.
Energy dissipation through wind-generated breaking waves
Institute of Scientific and Technical Information of China (English)
ZHANG Shuwen; CAO Ruixue; XIE Lingling
2012-01-01
Wave breaking is an important process that controls turbulence properties and fluxes of heat and mass in the upper oceanic layer.A model is described for energy dissipation per unit area at the ocean surface attributed to wind-generated breaking waves,in terms of ratio of energy dissipation to energy input,windgenerated wave spectrum,and wave growth rate.Also advanced is a vertical distribution model of turbulent kinetic energy,based on an exponential distribution method.The result shows that energy dissipation rate depends heavily on wind speed and sea state.Our results agree well with predictions of previous works.
Robust Dissipative Control for Nonlinear System with Sector Input
Institute of Scientific and Technical Information of China (English)
LuoQi; DengFei-qi; BaoJun-dong
2003-01-01
Based on the quadratic supply rate, the problem of robust dissipative control for a class of uncertain nonlinear system with sector nonlinear input is discussed. The uncertainty is described by bounded norm. It is shown that the robust dissipative control problem can be resolved for all admissible uncertainty, if there exists a storage function such that Hamilton Jacobi inequality holds. When the uncertainties of the system satisfy the matching condition, and input function within the boundedness of the sector, the closed loop system will be stronger dissipativeness, and the controller which we obtained in the paper is more flexible, because it contains an adjustable parameter for some certain range.
Calculation of Turbulent Boundary Layers Using the Dissipation Integral Method
Institute of Scientific and Technical Information of China (English)
MatthiasBuschmann
1999-01-01
This paper gives an introduction into the dissipation integral method.The general integral equations for the three-dimensional case are derved.It is found that for a practical calculation algorithm the integral monentum equation and the integral energy equation are msot useful.Using Two different sets of mean velocity profiles the hyperbolical character of a dissipation integral method is shown.Test cases for two-and three-dimensional boundary layers are analysed and discussed.The paper concludes with a discussion of the advantages and limits of dissipation integral methods.
Investigation of Power-Law Damping/Dissipative Forces
Mickens, Ronald E
2014-01-01
The properties of a one space-dimension, one particle dynamical system under the influence of a purely dissipative force are investigated. Assuming this force depends only on the velocity, it is demonstrated, in contrast to the case of linear damping, that there exist dissipative forces for which the particle \\textquotedblleft stops" in a finite time. It is also shown, by an explicit example, that other dissipative forces exist such that they produce dynamics in which the particle achieves zero velocity only after an infinite distance has been traveled. Possible applications of these results to more complex situations are discussed.