scholarly journals Planetary Temperatures in the Presence of an Inert, Nonradiative Atmosphere

2020 ◽  
Vol 39 (3) ◽  
pp. 69-85
Author(s):  
John Leslie Nicol
Keyword(s):  
Thermal Properties ◽  
Solar System ◽  
Inert Atmosphere ◽  
Thermal Parameters ◽  
Close Similarity ◽  
Light Radiation ◽  
Soil Layers ◽  
Radiation Processes ◽  
Surface Convection

AbstractThis study considers solid planets at about 300 K and an inert atmosphere having no interaction with associated radiation. Processes considered include transfer of energy from the surface skin to underlying layers depending on thermal properties. Temperatures of the surface depend on the rates of transfer of energy between soil layers. The atmosphere is warmed at base by contact with the surface, convection and turbulence distributing higher temperatures through the air. Comparisons between theoretical and measured temperatures show a close similarity. Mean planetary temperatures are calculated, depending on thermal parameters and the intensity of light/radiation from the particular solar system.

Two case histories of major frost heaving in refrigerated buildings: thermal analyses, repairs, and prevention

1988 ◽  
Vol 25 (3) ◽  
pp. 535-540
Author(s):  
Robert P. Chapuis
Keyword(s):  
Thermal Properties ◽  
Thermal Analyses ◽  
Large Error ◽  
Operating Conditions ◽  
Natural Soil ◽  
Case Histories ◽  
Frozen Soils ◽  
Soil Layers ◽  
Multilayered System ◽  
Frost Penetration

Two cases of major slab uplifts (15 and 41 cm) of the floors of two refrigerated buildings are analyzed. These uplifts were caused by vertical heaving of the natural soils, at depths between 2 and 4 m, during frost penetration. In one case, conditions are met that justify, with no risk of large error, the use of the equation of frost penetration into a multilayered system with latent heat. The thickness of the frozen natural soil, as measured in boreholes, corresponds closely to the value that could have been anticipated from the operating conditions and from the thermal properties of the insulation and of the backfilled and natural soil layers. The two repairs effected are described and recommendations to prevent the occurrence of these problems are given. Key words: frozen soils, heaving, building, case history.

scholarly journals Thermal Properties of Multilayer Nanocomposites Based on Halloysite Nanotubes and Biopolymers

2018 ◽  
Vol 2 (3) ◽  
pp. 41 ◽  
Author(s):  
Vanessa Bertolino ◽  
Giuseppe Cavallaro ◽  
Stefana Milioto ◽  
Filippo Parisi ◽  
Giuseppe Lazzara
Keyword(s):  
Thermal Properties ◽  
Cellulose Degradation ◽  
Oxidative Degradation ◽  
Middle Layer ◽  
Halloysite Nanotubes ◽  
Hydroxypropyl Cellulose ◽  
Inert Atmosphere ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Kinetics Of

This paper reports a novel procedure to fabricate multilayer composite biofilms based on halloysite nanotubes (HNTs) and sustainable polymers. Among the biopolymers, the non-ionic (hydroxypropyl cellulose) and cationic (chitosan) molecules were selected. The nanocomposites were prepared by the sequential casting of ethanol solutions of hydroxypropyl cellulose and aqueous dispersions of chitosan/HNTs. The composition of the bio-nanocomposites was systematically changed in order to investigate the effect of the hydroxypropyl cellulose/HNTs ratio on the thermal properties of the films, which were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). DSC studies were conducted in the static air (oxidative atmosphere), while TG measurements were carried out under nitrogen flow (inert atmosphere). The analysis of DSC data provided the enthalpy and the temperature for the oxidative degradation of the bio-nanocomposites. These results were helpful to estimate the efficacy of the well-compacted middle layer of HNTs as a flame retardant. TG experiments were performed at a variable heating rate and the collected data were analyzed by the Friedman’s method (non-isothermal thermogravimetric approach) with the aim of studying the kinetics of the hydroxypropyl cellulose degradation in the multilayer nanocomposites. This work represents an advanced contribution for designing novel sustainable nanocomposites with excellent thermal behavior as a consequence of their peculiar multilayer structure.

scholarly journals Measurement Method for the Simultaneous Determination of Thermal Resistance and Temperature Gradients in the DeterMination of Thermal Properties of Textile Material Layers

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6853
Author(s):  
Snježana Firšt Rogale ◽  
Dubravko Rogale ◽  
Željko Knezić ◽  
Nikolina Jukl
Keyword(s):  
Thermal Properties ◽  
Thermal Resistance ◽  
Temperature Gradients ◽  
Thermal Parameters ◽  
Textile Material ◽  
Insulation Material ◽  
Measuring Device ◽  
New Device ◽  
Air Layers

The thermal properties of most clothing products are still not designed according to engineering science due to the lack of simple and acceptable measuring equipment and methods; the type of thermal insulation material, the number of layers of clothing and their thickness are thus chosen empirically. The novelty of this study was the development of a new measuring device and method for simultaneous measurements in the determination of the thermal resistance in one or more textile material layers, such as in multilayer composite clothing. Temperature gradients of textile material layers are presented, as well as the theoretical principles of operation and practical results. Four materials for the production of protective jackets were selected, from which different combinations of composite clothing were constructed and the thermal parameters were measured with a new method and a new device, both individually for the built-in materials and for the composites. Subsequently, five test jackets with the same arrangement of textile material layers as the previously tested composites were produced, and measurements of important thermal parameters were recorded with a thermal mannequin. The determined temperature gradients and measurement results are presented, and based on these it was determined that the total thermal resistance was not equal to the algebraic sum of the resistances of the individual textile material layers in the horizontal position; it was, however, higher, increasing from 30% to 94% due to small air layers caused by crimping and protruding fibres of yarn in the textile fabrics. The same textile material layers built into clothing in the vertical position allowed the formation of significantly wider air layers that increased the thermal resistance by between 2.5 and 9 times.

scholarly journals SILATRANE-CONTAINING POLYMETHACRYLATES

2019 ◽  
Vol 14 (1) ◽  
pp. 82-89 ◽  
Author(s):  
V. V. Istratov ◽  
E. V. Andreeva ◽  
V. I. Gomzyak ◽  
V. A. Vasnev
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Three Dimensional ◽  
Gel Permeation Chromatography ◽  
Inert Atmosphere ◽  
Synthetic Methods ◽  
Ir And Nmr Spectroscopy ◽  
Gel Permeation ◽  
Melting And Crystallization Temperatures ◽  
Melting And Crystallization

The possibility of synthesizing silatrane-containing polymers was investigated using three different synthetic methods: the formation of silatrane fragments from polymers with trialkoxysilyl groups, the copolymerization of silatrane-containing monomers, and the reaction of silatranes with functional copolymers. The obtained polymethacrylate copolymers were characterized using gel permeation chromatography, IR and NMR spectroscopy. It was shown that depending on the synthesis scheme used, polymers were obtained in the form of three-dimensional structures or soluble products. It was established that the molecular weight of the synthesized polymers depended significantly on both the content of silatrane fragments and the synthesis technique used. It was shown that the modification of linear carboxyl-containing copolymers by silatranes allows the synthesis of high-molecular polymers with a high content of silatrane fragments. For the synthesized polymers, thermal properties were investigated, and the hydrophobicity of the surface of polymer films was also evaluated. It was found that all the studied polymers did not have clear melting and crystallization temperatures. The polymers were stable in an inert atmosphere up to 270-280 °C, whereas in air they decomposed at lower temperatures with the restructuring of the macromolecular skeleton and the formation of highly heat-resistant silicone structures. An increase in the content of silatrane moieties in the copolymers led to an increase in the hydrophilicity of polymers.

Measurement Method of Thermal Properties of Cementitious Bedding Materials and Unsaturated Soils: Hydraulic Influence on Thermal Parameters

2016 ◽  
Vol 40 (1) ◽  
pp. 20160027 ◽  
Author(s):  
C. Drefke ◽  
M. Schedel ◽  
J. Stegner ◽  
C. Balzer ◽  
V. Hinrichsen ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Unsaturated Soils ◽  
Measurement Method ◽  
Thermal Parameters ◽  
Bedding Materials

scholarly journals Main-belt comets: sublimation-driven activity in the asteroid belt

2015 ◽  
Vol 10 (S318) ◽  
pp. 99-110
Author(s):  
Henry H. Hsieh
Keyword(s):  
Thermal Properties ◽  
Solar System ◽  
Asteroid Belt ◽  
Main Belt ◽  
New Class ◽  
Solar System Objects ◽  
Main Asteroid Belt

AbstractOur knowledge of main-belt comets (MBCs), which exhibit comet-like activity likely due to the sublimation of volatile ices, yet orbit in the main asteroid belt, has increased greatly since the discovery of the first known MBC, 133P/Elst-Pizarro, in 1996, and their recognition as a new class of solar system objects after the discovery of two more MBCs in 2005. I review work that has been done over the last 10 years to improve our understanding of these enigmatic objects, including the development of systematic discovery methods and diagnostics for distinguishing MBCs from disrupted asteroids (which exhibit comet-like activity due to physical disruptions such as impacts or rotational destabilization). I also discuss efforts to understand the dynamical and thermal properties of these objects.

Fingerprints of the protosolar cloud collapse in the Solar System: Refractory inclusions distribution and isotopic anomalies in meteorites

2019 ◽  
Vol 15 (S350) ◽  
pp. 100-102
Author(s):  
Francesco C. Pignatale ◽  
Emmanuel Jacquet ◽  
Marc Chaussidon ◽  
Sébastien Charnoz
Keyword(s):  
Thermal Properties ◽  
Solar System ◽  
Building Blocks ◽  
Homogeneous Distribution ◽  
The Sun ◽  
Relative Age ◽  
Show Evidence ◽  
Collapsing Cloud ◽  
Isotopic Anomalies

AbstractIncreasing evidences suggest that the building blocks of Ca-Al-rich inclusions (CAIs) could have formed with the Sun, during the collapse of the parent cloud. However, determination of the relative age of CAIs relies on the homogeneous distribution of their short-lived radionuclide 26Al that is used as a chronometer. Some CAIs show evidence of 26Al/27 Al variation that is independent of decay.We investigate the dynamical and chemical evolution of refractories from the collapsing cloud to their transport in the protoplanetary disk focusing to the predicted isotopic anomalies resulting from 26Al heterogeneities.The interplay between the thermal properties of the dust, the isotopic zoning in the cloud and disk dynamics produce aggregates that resemble chondrites. An abrupt raise of 26Al close the center of the cloud followed by a plateau throughout the cloud best matches the observations. As a consequence, the 26Al -chronometer retains validity from the formation of canonical CAIs onward.

scholarly journals PHOTOTHERMAL TECHNIQUE FOR MEASURING THERMAL CONDUCTIVITY AND DIFFUSIVITY OF NANOFLUIDS: A NEW APPROACH

2018 ◽  
Vol 15 (29) ◽  
pp. 257-265
Author(s):  
R. HECHAVARRÍA ◽  
O. DELGADO ◽  
A. HIDALGO ◽  
S. ESPÍN ◽  
J. GUAMANQUISPE
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Side Surface ◽  
Heat Diffusion ◽  
Special Importance ◽  
Light Radiation ◽  
Heat Diffusion Equation ◽  
New Approach ◽  
Photothermal Technique ◽  
New Variant

Nanofluids have become nowadays of special importance because of their different uses in industry, therefore, to propose methods to calculate their thermal properties would be useful. In this work, a new variant for the calculation of thermal conductivity and diffusivity of nanofluids is proposed; the possibilities and limitations of this non-stationary method, which uses light radiation as the heat source, are studied. Here, the light is homogenously incident on one of the end surfaces of a cylinder that has a thermally insulated side surface, setting the temperature at the other end to a constant value, then the temperature distribution is obtained as a function of the coordinate and time; adjusting the theoretical model, parabolic heat diffusion equation, to the experimental data obtained. The conditions of validity of the method to measure thermal diffusivity and thermal conductivity of fluids are analyzed; as well as, the way in which it could be used to verify the validity of the Hamilton and Crosser (HC) model in the case of nanofluids. Currently, nanofluids are used to exchange heat, as they have been found to exceed the potential of conventional refrigerants; however, the calculation of thermal properties still does not offer definitive values.

Comparison of the Impact of the Ventilation Ducts on Thermal Properties of the Exterior Walls

2014 ◽  
Vol 899 ◽  
pp. 241-244 ◽  
Author(s):  
Hana Sevcikova ◽  
Eva Rykalová ◽  
Radek Fabian
Keyword(s):  
Thermal Properties ◽  
Thermal Parameters ◽  
Masonry Structures ◽  
Air Inlet ◽  
Ventilation Ducts ◽  
The Impact ◽  
Structural Solutions

Implementation of the ventilation ducts is one of the ways how to reduce the moisture in the vertical masonry structures. Functional ventilation ducts provide air inlet and outlet, which absorb diffusing moisture from the rehabilitated walls in these ducts. This causes the reduction of moisture in the structure. The implementation of the ventilation ducts is associated with the worsening of thermal parameters of the rehabilitated walls. This paper compares three variants of structural solutions of ventilation ducts and their impact on thermal parameters of the rehabilitated structure.

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