Showing papers on "Thermal reservoir published in 1994"

Io's heat flow from infrared radiometry: 1983–1993

Abstract: We report the following results from a decade of infrared radiometry of Io: (1) The average global heat flow is more than approx. 2.5 W/sq.m, (2) large warm (less than or equal to 200 K) volcanic regions dominate the global heat flow, (3) smal high-temperature (greater than or = 300 K) 'hotspots' contribute little to the average heat flow, (4) thermal anomalies on the leading hemisphere contribute about half of the heat flow, (5) a substantial amount of heat is radiated during Io's night, (6) high-temperature (greater than or = 600 K) 'outbursts' occurred during approx. 4% of the nights we observed, (7) 'Loki' is the brightest, persistent, infrared emission feature, and (8) some excess emission is always present at the longitude of Loki, but its intensity and other characteristics change between apparitions. Observations of Io at M(4.8 micrometer), 8.7 micrometer, N(10 micrometer), and Q(20 micrometer) with the Infrared Telescope Facility presented here were collected during nine apparitions between 1983 and 1993. These measurements provide full longitudinal coveraged as well as an eclipse observation and the detection of two outbursts. Reflected sunlight, passive thermal emission, and radiation from thermal anomalies all contribute to the observed flux densities. We find that a new thermophysical model is required to match all the data. Two key elements of this model are (1) a 'thermal reservoir' unit which lowers daytime temperatures, and (2) the 'thermal pedestal effect' which shifts to shorter wavelengths the spectral emission due to the reradiation of solar energy absorbed by the thermal anomalies. The thermal anomalies are modeled with a total of 10 source components at five locations. Io's heat flow is the sum of the power from these components.

Thermal storage systems for buildings

Abstract: Apparatus and processes related to thermal storage and exchange systems for use in buildings to selectively cool and/or heat a heat storage medium and cause said medium to reversibly pass between a liquid phase and a solid phase without requiring a complete discharge of a thermal reservoir between phase changes.

Thermal analysis instrument

Abstract: The temperature of a heat reservoir is varied according to a linear function which is AC modulated. At this time, the temperature difference between two points located in a heat flow path going from the heat reservoir to an unknown sample is measured. Also, the temperature difference between two points located in a heat flow path going from the heat reservoir to a reference sample is measured. These two pairs of points are arranged symmetrically. Then, the resulting signals are demodulated, and each signal is divided into an AC component and a low-frequency component. Using these signals, the DSC signal is separated into a heat capacity component and a latent heat component.

Quasi-infinite heat source/sink

Abstract: An apparatus and method for controlling the temperature of an object, in particular a semiconductor wafer support structure in a wafer processing chamber. A gas gap is created between the two adjacent objects of different temperatures. The pressure in the gap is adjusted to control the thermal conductivity of the gas between the two structures. To have a large heat flow between the two objects so that their temperatures can be closely matched, the pressure is increased. To maintain the temperature of the object sought to be controlled regardless of the temperature of the adjacent item (heat source/sink) the pressure is reduced to a strong vacuum (acting as insulation) so that very little heat flow occurs through the gas gap. Localized control acts together with a local heat sink to precisely control the temperature of a semiconductor support structure pedestal/cathode to maintain the uniformity of the temperature of the wafer during processing to prevent wafer surface process anomalies due to variations and gradients in temperature. Heating and cooling in one structure can be controlled by using alternating gas gaps. A heating heat source/sink is placed adjacent to a cooling heat sink/source both of which face the object whose temperature is to be controlled.

Evolution of coherences and populations in the secular approximation.

Abstract: We consider systems coupled to a heat reservoir that has a Debye density of states. In particular, starting from master equations derived in the secular (or rotating-wave) approximation, we derive expressions for the decoherence rates and energy-jump moments for systems and couplings of varying degrees of generality. We also furnish the semiclassical analogs of these expressions. Finally, using the jump moments, we examine various aspects of the energy relaxation to thermal equilibrium.

振動制御形熱輸送管に関する研究 : 第1報,液体物性の影響

Abstract: In the present report, the effect of liquid properties on the effective thermal diffusivity of the oscillation-controlled heat transport tube (the so-called dream pipe) is investigated. First, a slip flow model is presented to investigate the fundamental mechanism and the governing quantities of this phenomena. Results of the analyses show that cascade heat transport between the stagnant boundary layer and the core liquid, which is caused by phase shift between the radial conduction heat-flux and the oscillation, is the fundamental mechanism of the phenomena. Next, it is found that the effective thermal diffusivity reaches a maximum at a value of the thermal diffusivity of the liquid because the phase shift increases with increasing thermal diffusivity. Finally, it is shown that water is one of the desirable operating liquids of the heat transport tube of this type.

In situ determination of thermal properties of sediments using a friction-heated probe source

Abstract: Marine heat flow measurements usually require inserting temperature sensor probes into seafloor sediments. The probe entry displaces the sediments and causes frictional heating along the probe-sediment interface. Since the probe cools at a rate dependent primarily upon the sediment's thermal conductivity and heat capacity, analysis of the cooling data can yield not only ambient equilibrium temperature but also thermal properties. This paper describes a study which simulates the cooling process with a finite element method. Solutions are given for seven model-defining parameters using a least squares nonlinear inversion algorithm. Advective mass-heat transfer is incorporated by introducing a heat partition factor into the initial condition. The simulation provides a means of estimating frictional heat that can be considered as a heat pulse to determine thermal conductivity from an asymptotic relation between temperature rise and inverse time. Our simulation inversion is iterated until the simulated conductivity matches the “asymptotic” conductivity. Field tests indicate that the conductivity and equilibrium temperature can be satisfactorily determined from 5-min long recordings of temperature for 3 mm-diameter probes if the cooling is purely radial. For probes with sensors near their tips, conductivity determination is rendered uncertain because of more complex two-dimensional geometry and heating process, but the equilibrium temperature can still be determined.

Heat storage apparatus and method

Abstract: A heat storage apparatus includes a tank containing a heat storage medium and having an upper region and a lower region for holding the heat storage medium at respective temperatures above and below atmospheric temperature. To reduce heat losses and increase flexibility of use, an intermediate region having heat storage medium is maintained in the tank between the upper and lower regions at a temperature between the upper and lower temperatures. The desired temperature of the intermediate region is maintained by heating or cooling its heat storage medium, for example by use of an otherwise unused low-grade heat source.

Thermodynamic optimization of heat/cold sink extenders in thermoelectric cooling assemblies

Abstract: The heat sink extender serves many purposes in the overall design of thermoelectric cooling assembly. One purpose is to serve as a thermojunction, another involves temperature control. The optimization of the heat sink extender is discussed and several schemes are considered. (AIP)

Regenerative type burner and storage type heat exchanging system available therefor

Abstract: The invention relates to a storage type heat exchanging system for performing heat exchange by alternately passing a combustion exhaust gas, which is a high temperature fluid, and an air for combustion, which is a low temperature fluid, through a stationary heat reservoir, and a regenerative type burner for effecting combustion by the use of a preheated air of high temperature provided by the system. The storage type heat exchanging system comprises a porous heat reservoir (1) which is divided into three or more compartments in a circumferential direction, entrance exit means (6) which is in the form of a dual pipe and is divided into a feed chamber (6a) and an exhaust chamber (6b), and switching means (3) for providing cutoff between the heat reservoir (1) and the entrance/exit means (6) and selectively providing communication between the heat reservoir (1) and the entrance/exit means (6) by means of a feed communication hole (5) and an exhaust communication hole (4) which are provided in such a positional relationship that the both holes are not existent in any one of the compartments (9, 10, 11) of the heat reservoir (1) at the same time and form the vacant compartment (10), through which any fluid does not flow, at at least a location between the compartment (11), through which an exhaust gas flows, and a compartment (12), through which air flows. Further, provided in the storage type heat exchanging system is a fuel nozzle (31) extending centrally therethrough to continuously jet a fuel, and an air of high temperature for combustion is caused to be jetted from the heat reservoir, thereby constituting a regenerative type burner. Also, the heat exchanging system in which a flow direction is not changed can be provided by providing the entrance/exit means (6, 6) and switching means (3, 3) before and behind the heat reservoir (1), without providing the fuel nozzle (31).

Solar energy collector uses two-component heat transport medium - one in contra-flow to cover flow heat flow pattern reducing amount of heat surrendered back to atmosphere

Abstract: A heat concentrating and heat pumping flat solar energy collector (2) constructed on a support (1). The novelty is that a fluid heat transporting medium consists of two components of which one evaporates at the operating temp. Further, that the heat transport medium seeps through a heat insulating element (3), in the opposite direction to the direction in which heat spreads towards the cover plate (2). Further that the heat transport medium increasingly absorbs heat from one or both components. Further the evaporated components and liquid residue dun along a light-absorbing area (4) to lower end of collector, such that the heat transport medium then passes through tubes (5) behind the light-absorbing area (4) so that heat is surrendered in contra flow to the light-absorbing area (4). Further that the tubes (5) or heat-exchanger vessels behind the light-absorbing surface (4) are kept very thin and prevent a return flow of the fluid. Pref., when the heat transporting medium is evaporated or condensed, use is made of the external energy of the heat transport medium so that when heat is surrendered at a lower temp. level than the max. collector temp., the heat which is extending towards the cover disc, is pumped back, and that additional heat can be taken up from the surroundings. ADVANTAGE - The appts. reduces the amount of heat energy surrendered back to the surrounding atmosphere.

Method and apparatus for preventing corrosion of heat source water route for air conditioning

Abstract: PURPOSE:To prevent corrosion of a conduit in contact with heat source water by making nitrogen gas bubble in the water in a heat source water circulation passage of a water heat source air conditioner facility. CONSTITUTION:Nitrogen gas is made to bubble in heat source water in a heat reservoir 1 or a bubbling tank provided in heat source water circulation passages 5, 6 of a water heat source air conditioner facility 3. The gas to be used for the bubbling can be obtained by a nitrogen gas generator 23 for separating the air into oxygen enriched gas and nitrogen gas by utilizing a hollow yarn film. Part or entirety of the reservoir 1 is formed in sealed tanks 7, 8 which are substantially shut OFF from the atmosphere, air diffusing tubes 20 each formed of a porous tube connected to the generator 23 are mounted under water of the tanks 7, 8, and exhaust gas passages 21, 22 connected from the tanks 7, 8 to the exterior are provided. Thus, dissolved oxygen in circulation heat source water can be reduced to prevent progress of corrosion of a steel of the conduit in contact with the water.

Recent Developments in the Quantum Nonlinear Dimer: Hopf Bifurcations, Time Evolution, and Thermal Stability

Abstract: A simple but rich nonlinear structure that has received a great deal of attention in the last few years is the quantum nonlinear dimer [1] in which a quasiparticle, such as an electron or an excitation, shuttles back and forth between two sites while interacting so strongly with a boson field, e. g. the vibrations of the system, that the quasiparticle evolution becomes nonlinear. The discrete nonlinear Schroedinger equation in various forms has served as the evolution equation for this structure [2]. The advantage of studying this small system lies in the fact that insights into many issues of interest on extended systems can be gained without having to grapple with the considerable additional complexities which extended systems introduce into the problem. Much work has been done on the nonlinear dimer [3–6]. Here we report on a few developments that have occurred recently in our investigation of the system. They are (i) exact solutions for the quantum nonlinear dimer in the absence of dissipation, (ii) a new approach we have constructed to analyze the thermal stability of nonlinear structures, and (iii) bifurcation behaviour we have encountered in the interaction of the dimer with a heat reservoir. The first two will be mentioned in the rest of this section and the third in section 2.

Operation control method of cogeneration system

Abstract: PURPOSE:To perform the backup of heat reservoir equipment groups by a simple control and to realize an arbitrary thermoelectric ratio by purchasing power, in a system including an engine driving cogeneration system, a heat pump and a heat storage tank. CONSTITUTION:An arbitrary thermoelectric ratio is realized by a cogeneration system CGS and a heat pump H by composing the side of heat load QL and the heat output side of heat reservoir equipment groups via a heat storage tank ST, by arranging the cogeneration system CGS and the heat pump H as heat reservoir equipments in parallel, by executing the power followup operation when the thermoelectric ratio is small, by storing excess heat in the heat storage tank ST, by utilizing the heat of the heat storage tank ST when the thermoelectric ratio is large and by purchasing power corresponding to the remaining heat load QL and power load WL.

Nuclear Spin Relaxation Theory

Abstract: Chapter 2 focused on the evolution of a nuclear spin system without examining how it achieves thermal equilibrium with the lattice by energy exchange. The lattice consists of all degrees of freedom, except those of the nuclear spins, associated with molecular rotations and translations in physical systems such as liquid crystals. Spin-lattice relaxation describes how the system of nuclear spins evolves towards thermal equilibrium with the large heat reservoir, the lattice. The spin relaxation rates with which the nuclei arrive at their equilibrium magnetization may be experimentally determined. There is a well-defined connection between the relaxation rates and the dynamics of the lattice provided that the coupling interactions between the nuclear spin system and the lattice are known. Thus, nuclear spin relaxation may be used to study motional processes in molecular systems.

Quasiscalar map for a kicked spin 12

Abstract: We study the semiclassical dynamics of a spin 1 2 system polarized in an external magnetic field, coupled to a dissipative heat reservoir and periodically perturbed by an instantaneous rotation. We construct a quasiscalar map for a dynamical invariant of the unperturbed system and investigate its characteristics for both the Rotating Wave Approximation and the Full Coupling descriptions of the dissipative environment in terms of the kicking strength and the orientation of the rotation axis.

Modeling the unsteady heat and mass transfer in the vapor outlet channel of a radiative-evaporative thermal protection system

Abstract: The system of equations and boundary conditions for the problem of modeling the heat and mass transfer processes in the plane channel of a combined thermal protection system of the radiative-evaporative type is formulated for time-dependent external heat flux and pressure. The effect of the problem parameters on the basic characteristics of these processes is considered. The possibility of nonmonotonic behavior of the evaporation rate and evaporation surface temperature in the presence of a monotonically increasing heat flux is established. A physical explanation of these effects is given.

A possible unitarity defect of theS-matrix

Abstract: The familiar analogy in the quantum theory between the time evolution of an isolated system and the thermal equilibrium of a system with a thermostat or heat reservoir leads us to the hypothesis of a «temporal equilibrium» of any so-called isolated system with the physical space-time. Small virtual deviations from such an equilibrium imply a non-unitarity extension of the quantum state equation giving a tiny unitarity defect of theS-matrix.

Classical and quantum dissipation in non homogeneous environments

Abstract: 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 Langevin equation with nonlinear multiplicative noise and a position-dependent fluctuation- dissipation theorem associated to non homogeneous dissipative forces. When time-modulation of the noise is present, a new force term is predicted besides the dissipative and random ones. The model is quantized to obtain the non homogenous influence functional and master equation for the reduced density matrix of the Brownian particle. The quantum evolution equations reproduce the correct Langevin dynamics in the semiclassical limit. The consequences for the issues of decoherence and localization are discussed.

Heat production kinetics and the scope for thermal self-ignition in wheat drying

Abstract: Heat production has been examined at various oxygen partial pressures in the oxidation and thermal destruction of grain products by the use of a DAK-1-2 differential microcalorimeter Estimates have been made on the adiabatic induction periods and critical sizes of the grain product layers on a metal surface (boundary conditions of the first kind) in the absence of heat transfer from the other surface It is found that thermal self-ignition will occur in degenerate mode when thermal destruction is decisive