Interior Heating Research Articles

Interior Heating for Hybrid and Electric Vehicles

Interior Heating for Hybrid and Electric Vehicles

A contraction model for the flattening and equatorial ridge of Iapetus

Others have explained the excess flattening of Iapetus by a model in which the moon formed at a high spin rate, achieved isostatic equilibrium by very rapid interior heating caused by short-lived radioactive isotopes (SLRI), and subsequently cooled, locking in the excess flattening with respect to an equilibrium shape at its present spin rate. Here we propose an alternate model that does not require an unusually high initial spin rate or the SLRI. The initial formation of Iapetus results in a slightly oblate spheroid with porosity >10%. Radioactive heating by long-lived isotopes warms the interior to about 200 K, at which point it becomes ductile and the interior compacts by 10%, while the 120 km-thick exterior shell remains strong. The shell must deform to match the reduced volume of the ductile interior, and we propose that this deformation occurs along the equator, perhaps focused by a thinner equatorial shell. The final shape of the collapsed sphere matches the observed shape of Iapetus today, described as an oblate ellipse, except along the equator where strain concentration forms a broad ridge. To maintain this non-equilibrium shape, the thickness of the shell must exceed 120 km. Testing the equatorial focusing hypothesis will require a model that includes non-linear processes to account for the finite yield strength of the thick lithosphere. Nevertheless, we show that the stress in the lithosphere generated by the contraction of the interior is about 3 times greater than the stress needed to deform the lithosphere, so some type of lithospheric deformation is expected.

Preparation and Synthetic Mechanism of Silicon Carbide Nanometer Whiskers

β-SiC nanometer whiskers were prepared in a double heating furnace that is composed of the interior and exterior heating systems. The SiO2 nanometer powder and char pyrolyzed from phenol formaldehyde resin were used as starting materials. The effects of sintering temperature and holding time on β-SiC nanometer whiskers were investigated and the synthetic mechanism was studied. It was revealed that the β-SiC nanometer whiskers, with the diameter of 50-80nm and the aspect ratio of 50-300, can be prepared at 1300°C for 60 min. The purity of the β-SiC nanometer whiskers is about 99%.

Optimal Inverse Design Problem in Determining Cooling Conditions for High-Speed Motors

The effective optimal and practical time-dependent heat transfer coefficients of the cooling passage for high-speed motors are determined in a three-dimensional optimal control problem. The control algorithm utilizing the steepest descent method and a general purpose commercial code CFX4.4 is applied successfully in accordance with the design (or desired) temperature distributions on the interior heating surface. Two different design temperature distributions are used to illustrate the validity of determining both the effective optimal and practical heat transfer coefficients. Results of the numerical simulation show that the reliable estimated effective practical heat transfer coefficients can be obtained by using the present optimal inverse design (or optimal control) algorithm.

Analytical thermal model and characterization of lateral thermal effects in AlInGaAs vertical-cavity top-emitting lasers

An optimized comprehensively analytical thermal model was developed in accordance with interior heating characteristics of a gain-guided, top-emitting vertical-cavity surface-emitting laser with c.w. operation under room temperatures. Lateral thermal effects in AlInGaAs/AlGaAs vertical-cavity surface-emitting lasers were calculated analytically in detail. The comprehensively analytical solutions exhibited a clearer physical picture of the lateral heat-flux diffusion. The theoretical predicts of the interior thermal variation within the device were consistent with the experimental results as well. The work provides a useful tool for investigation of thermodynamic properties of the vertical-cavity surface-emitting lasers under thermal steady state, optimization of the device structure and control of the threshold current and power saturation effect, especially for the lateral thermal crosstalk in 2-dimensional arrays.

05/02586 Energy production from biomass pyrolysis: a new coefficient of pyrolytic valorisation

The influence from structural changes, heat transfer properties of dry wood and pyrolysis mechanism on the pyrolysis of large wood particles were studied. Measurements of temperature distribution and mass loss were performed on cylindrical samples of dry birch wood during pyrolysis in an inert atmosphere at 700°C. A model of wood pyrolysis was modified to include structural changes. Comparisons of measurements and model simulations show that the inclusion of a shrinking model reduces the time of pyrolysis substantially. The varying interior heating rate was found to influence the choice of pyrolysis mechanism. Of four pyrolysis mechanisms found in literature, only one was found to be in agreement with the measurements.

Molecular Gas and Dust in the Massive Star Forming Region S 233 IR

The massive star forming region S 233 IR is observed in the molecular lines CO J = 2–1, 3–2, NH3 (1,1), (2,2) and the 870 um dust continuum. Four submillimeter continuum sources, labelled SMM 1–4, are revealed in the 870 um dust emission. The main core, SMM1, is found to be associated with a deeply embedded near infrared cluster in the northeast; while the weaker source SMM2 coincides with a more evolved cluster in the southwest. The best fit spectral energy distribution of SMM1 gives an emissivity of β = 1.6, and temperatures of 32 K and 92 K for the cold- and hot-dust components. An SMM1 core mass of 246 M☉, and a total mass of 445 M☉ are estimated from the 870 um dust continuum emission. SMM1 is found to have a temperature gradient decreasing from inside out, indicative of the presence of interior heating sources. The total outflow gas mass as traced by the CO J = 3–2 emission is estimated to be 35 M☉. Low velocity outflows are also found in the NH3 (1,1) emission. The non-thermal dominant NH3 line width as well as the substantial core mass suggest that the SMM1 core is a ``turbulent, massive dense core", in the process of forming a group or a cluster of stars. The much higher star formation efficiency found in the southwest cluster supports the suggestion that this cluster is more evolved than the northeast one. Large near infrared photometric variations found in the source PCS-IR93, a previously found highly polarized nebulosity, indicate an underlying star showing the FU Orionis type of behavior.

Modelling and measurements of the pyrolysis of large wood particles

The influence from structural changes, heat transfer properties of dry wood and pyrolysis mechanism on the pyrolysis of large wood particles were studied. Measurements of temperature distribution and mass loss were performed on cylindrical samples of dry birch wood during pyrolysis in an inert atmosphere at 700°C. A model of wood pyrolysis was modified to include structural changes. Comparisons of measurements and model simulations show that the inclusion of a shrinking model reduces the time of pyrolysis substantially. The varying interior heating rate was found to influence the choice of pyrolysis mechanism. Of four pyrolysis mechanisms found in literature, only one was found to be in agreement with the measurements.

Binary‐induced Neutron Star Compression, Heating, and Collapse

We analyze several aspects of the recently noted neutron star collapse instability in close binary systems. We utilize (3 + 1) dimensional and spherical numerical general relativistic hydrodynamics to study the origin, evolution, and parametric sensitivity of this instability. We derive the modified conditions of hydrostatic equilibrium for the stars in the curved space of quasi-static orbits. We examine the sensitivity of the instability to the neutron star mass and equation of state. We also estimate limits to the possible interior heating and associated neutrino luminosity that could be generated as the stars gradually compress prior to collapse. We show that the radiative loss in neutrinos from this heating could exceed the power radiated in gravity waves for several hours prior to collapse. The possibility that the radiation neutrinos could produce gamma-ray (or other electromagnetic) burst phenomena is also discussed.

Near-Surface Ice on Mercury and the Moon: A Topographic Thermal Model

A thermal model that can be easily adapted to craters of arbitrary shape is developed and applied to high-latitude impact craters on Mercury and the Moon, Chao Meng Fu crater at -87.5°L on Mercury, an unnamed bowl-shaped crater at 86.7°L on Mercury, and Peary crater at 88.6°L on the Moon. For an assumed input topography and grid of surface elements, the model computes for each element the irradiation from direct insolation and reflected and emitted radiation from other elements, taking into account shadowing by the walls of the crater, partial obscuration of the solar disk near the poles and the diurnal, orbital, and seasonal cycles. Temperatures are computed over the surface grid as functions of depth and time from the surface to a specified depth and over the pertinent astronomical cycles, including the effects of direct and indirect surface irradiation, infrared radiation, heat conduction, and interior heating. Vapor fluxes and ice recession times are computed as functions of ice depth over the surface grid. Temperatures profiles, vapor fluxes, and ice recession times were computed for flat surfaces not associated with craters near the poles of Mercury and the Moon. It was found that water ice could have existed throughout geologic time within the maximum radar detection depth of recent observation of Mercury (J. K. Harmon and M. A. Slade, 1992, Science 258, 640-643) poleward of ∼87-88°L on Mercury and poleward of ∼73°L on the moon. For Chao Meng Fu crater it was found that ∼40% of the crater floor is permanently shadowed from direct solar insolation, while the remainder of the crater floor is periodically illuminated by a partially obscured Sun. Temperatures at the upper levels of the south wall can slightly exceed 550 K. Surface temperatures in the permanently shadowed region of the crater floor are under ∼130 K, which could have allowed water ice to exist throughout geologic time within the radar detection depth of recent observation of Mercury. For the small bowl-shaped crater on Mercury, it was found that most of the crater is permanently shadowed from direct solar radiation, except for a narrow semicircular band bordering the north rim. However, temperatures in the permanently shadowed region periodically reach a maximum near ∼315 K due to efficient heating of the small crater by thermal emission and reflection from the small sunlit region, which periodically reaches temperatures exceeding 630 K. Water ice could not have existed throughout geologic time anywhere in this crater within the radar detection depth. For Peary crater on the Moon, the entire crater floor is permanently shadowed from direct solar insolation with maximum temperatures under 120 K. The upper level of the north wall periodically reaches a maximum temperature near 310 K. The low temperatures on the crater floor would have allowed water ice to exist near the surface throughout geologic time, provided that the Moon's obliquity was always as low as it is at present.

An Improved Algorithm for Inverse Design of Thermal Problems With Multiple Materials

An optimization scheme and matrix partitioning strategy are developed in conjunction with a boundary element solution procedure for inverse design in heat transfer. The optimal control problem is to locate interior heating or cooling passages inside a coated conducting domain to achieve a desired boundary temperature when the heat flux is specified (or vice versa). As the interior passages can be parameterized with a few variables, the optimization problem is of low dimension, the matrix partitioning scheme for the boundary element system and optimization search procedure lead to a fast computational scheme for this class of problems.

Convective heating of the inner core of red giants prior to the peak of the core helium flash

view Abstract Citations (6) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Convective heating of the inner core of red giants prior to the peak of the core helium flash Cole, P. W. ; Demarque, P. ; Deupree, R. G. Abstract The effects of convective overshooting across the temperature inversion in red giant cores have been investigated theoretically, using a two-dimensional and three-dimensional hydrodynamic model of the core helium flash. The model is based on a simple heating algorithm which can be easily incorporated into a variety of stellar evolution codes. On the basis of the numerical results it is found that: (1) convective overshooting led to substantial heating of the material underneath the temperature inversion, producing a smoother temperature profile; (2) up until one week before the time of maximum temperature, interior heating is unimportant, but alters the standard relation of maximum temperature and density at the point of maximum temperature; and (3) overshooting redistributed the mass from the location of maximum temperature. The contribution of internal heating to the subsequent evolution of the core of a red giant is also discussed. Model estimates of the selected properties of core helium flash sequences at the time of maximum temperature are given in a table. Publication: The Astrophysical Journal Pub Date: April 1985 DOI: 10.1086/163067 Bibcode: 1985ApJ...291..291C Keywords: Red Giant Stars; Stellar Cores; Color-Magnitude Diagram; Convective Heat Transfer; Globular Clusters; Stellar Mass; Stellar Temperature; Thermonuclear Reactions; Three Dimensional Models; Astrophysics full text sources ADS |

A survey of the core helium flash with dynamic convection

Core helium flash model parameters were varied to examine their effects in an analytical study of the convective heating of a stellar interior within the core convection zone. Several models of a helium core were considered in terms of an angular zoning-eddy viscosity combination that yielded the highest interior heating rate and lowest peak temperature. Two separate results were obtained for noncentral core helium flashes, one in which the flash point was strong enough to produce inward directed movement of the burning front, the second in which the burning front does not propagate. For central core helium flashes, dominated by density and temperature, higher initial density models produce more violent, higher temperature, more extensive nuclear process phenomena. It is concluded that, in some instances, penetration of the hydrogen burning shell by small amounts of high temperature material is possible.

Near-field absorption in a circular cylinder from electric and magnetic line sources.

A homogeneous, lossy circular cylinder is used as a simple model of a biological object in which interior heating is produced by the absorption of electromagnetic waves. For this model, we determined the optimum frequency, polarization, orientation and shape of applicators. Analytical and numerical results are given for both electric and magnetic line sources, with three different polarizations relative to the cylinder. Coupling efficiencies and contour plots are presented for a range of parameters. One particularly interesting result is the production of maximum energy deposition at the center of a cylinder of muscle tissue when exposed in the 100-MHz frequency range by the use of four applicators surrounding the cylinder.

Complejo administrativo comercial – Lausana, Suiza

Administrative and commercial complex - Lausanne - Switzerland In an area which is being rebuilt in the centre of Lausanne, a 145,000 m 2 administrative and commercial complex has been built. It consists of a low body with 3 levels, arranged as platforms above the street and in the shape of terraces with gardens whereby a 4,000 m 2 area reserved for pedestrians has been created. On this lower part, high buildings have been constructed in harmony with each other. The building system consists of an upper structure with big beams and ribs which support the facade panels. The structure rests upon 4 big central columns and two on the side, whereby a diaphanous look has been achieved, further increased by mobile partition walls by which future needs also can be attended to. The light exterior enclosures were thoroughly studied and tested so as to provide total protection against dust and outer noise. Further the construction is equipped with interior heating and cooling installations and insulation from sound. This new urban complex does not attempt to adapt itself to the surrounding environment, but its lines are rather an expression of the architecture of tomorrow.

Interior resistance heated open tube epitaxial reactor

The construction of an open tube horizontal type reactor with interior heating produced by a tape-shaped resistance is described, which is intended to be used in laboratory work for silicon epitaxial growths by hydrogen reduction of silicon tetrachloride. The reactor is able to grow six 22 mm maximum diameter slices, with a thickness variation among the slices about the mean value of less than ±2·5%.

Interior Heating in Metal Work

Interior Heating in Metal Work