scholarly journals Thermophysical Investigation of Asteroid Surfaces. I. Characterization of Thermal Inertia

2021 ◽  
Vol 2 (4) ◽  
pp. 161
Author(s):  
Eric M. MacLennan ◽  
Joshua P. Emery
2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Dora Foti ◽  
Michela Lerna ◽  
Vitantonio Vacca

Masonry is a composite material largely used in construction. It exhibits several advantages, including significant compressive strength, thermal inertia, and aesthetic beauty. A disadvantage of masonry is mainly related to the inadequate shear strength due to the poor capacity and ductility of the adopted mortar. This aspect is crucial in seismic areas. In this paper, the behavior of polyurethane foams, used as adhesives for the construction of thin joints brick masonry walls, has been investigated. First, the characterization of components was carried out, followed by laboratory uniaxial tests on masonry walls and shear tests on triplets. Moreover, a comparison of the behavior of the foam-brick walls with respect to the traditional mortars masonry was carried out, as the type of joints varies and the arrangement of the holes of the bricks varies with respect to the direction of the applied load. Results provide indications on which adhesive has to be adopted for masonry buildings in reference to the site of construction (i.e., seismic hazard).


Author(s):  
Sushobhan Sen ◽  
Jeffery Roesler

Rigid pavements have an impact on the urban heat island (UHI) and hence the surrounding environment and human comfort. Currently, most studies use a mesoscale approach in UHI characterization of pavements. This study proposes a microscale approach that can be incorporated into a pavement life-cycle assessment (LCA). The heat flux of various concrete pavements containing layers of varying thermal diffusivity and inertia was simulated. The surface pavement radiative forcing (RFp) was developed as a metric for use in a pavement LCA. Additionally, the heat conducted and stored in each concrete pavement system was analyzed using an average seasonal day metric to understand the temporal pavement energetics. Of the various thermal cases, only a higher albedo surface significantly changed the RFp for a fixed climate. However, a time lag was induced by the thermal inertia of the base course, which decreased the amount of heat conducted out of the pavement at night by storing heat in the base course for a longer time, effectively reducing nighttime UHI. Diurnal variations in thermal behavior can be controlled by changing the thermal properties of subsurface layers, which can be used to partially mitigate UHI.


2020 ◽  
Vol 172 ◽  
pp. 14008
Author(s):  
Adrien François ◽  
Laurent Ibos ◽  
Vincent Feuillet ◽  
Johann Meulemans

The thermal resistance of a wall can be readily measured in steady-state. However, such a state is seldomly achieved in a building because of the variation of outdoor conditions as well as the high thermal inertia of building materials. This paper introduces a novel active (dynamic) method to measure the thermal resistance of a building wall. Not only are active approaches less sensitive to external temperature variations, they also enable to perform measurements within only a few hours. In the proposed methodology, an artificial thermal load is applied to a wall (heating of the indoor air) and its thermal response is monitored. Inverse techniques are used with a reduced model to estimate the value of the thermal resistance of a wall from the measured temperatures and heat fluxes. The methodology was validated on a known load-bearing wall built inside a climate chamber. The results were in good agreement with reference values derived from a steady-state characterization of the wall. The method also demonstrated a good reproducibility.


1986 ◽  
Vol 64 (9) ◽  
pp. 1217-1220 ◽  
Author(s):  
P. Cielo ◽  
S. Dallaire ◽  
G. Lamonde ◽  
S. Johar

The measurement of thermal parameters is a useful tool for the evaluation of compositional or structural properties of materials of industrial interest. The increasing use of noncontact photothermal techniques to generate and sense thermal fields in materials makes thermal characterization an attractive approach for in-plant quality monitoring and process control. In an effort to increase the reliability of such measurements in conditions of unknown surface emissivity, an integrating-cavity technique is described for a quantitative evaluation of the thermal inertia of the inspected material. An analysis of the performance of such a technique as a function of the cavity geometry and internal reflectivity is presented. Examples of applications to the characterization of manufactured ceramic materials with different porosity contents are described.


2019 ◽  
Vol 22 (1) ◽  
Author(s):  
Martín Wieser-Rey ◽  
Silvia Onnis ◽  
Giuseppina Meli

Resumen Las soluciones constructivas tradicionales y contemporáneas han demostrado tener serias limitaciones en la solución del déficit cualitativo y cuantitativo de la vivienda y el equipamiento, de igual manera, las evidencias del desempeño térmico son igualmente desalentadoras. Es por lo que se indaga sobre la capacidad de la tierra alivianada de brindar confort térmico en los edificios, considerando los diferentes climas del territorio peruano y comparándola con los sistemas constructivos más comunes en el medio: el adobe y la albañilería de ladrillo. A partir de la caracterización previa de las cualidades térmicas de los componentes y de la realización de simulaciones térmicas dinámicas, comparando el desempeño de diferentes prototipos digitales, se identificaron las virtudes de la tierra alivianada por el marcado equilibrio entre una masa térmica media y una conductividad térmica relativamente baja, siendo los únicos que logran cumplir con las exigencias de la actual norma peruana de eficiencia energética para el caso de los climas más fríos. Adicionalmente de destaca la composición a partir de materiales naturales, renovables y biodegradables que son ventajas ecológicas. Palabras clave: arquitectura bioclimática; arquitectura sostenible; climatización pasiva; confort térmico; inercia térmica; simulación térmica; sistema constructivo; transmitancia térmica   Abstract Traditional and contemporary construction systems have shown serious limitations in the solution of the qualitative and quantitative deficit of housing and equipment, in the same way, the evidence of thermal performance is equally discouraging. That is why we inquire about the ability of the land relieved to provide thermal comfort in buildings, considering the different climates of the Peruvian territory and comparing it with the most common construction systems in the environment: adobe and brick masonry. From the previous characterization of the thermal qualities of the components and the realization of dynamic thermal simulations, comparing the performance of different digital prototypes, the virtues of the earth alleviated by the marked balance between a medium thermal mass and a conductivity were identified relatively low thermal, being the only ones that manage to meet the requirements of the current Peruvian energy efficiency standard in the case of colder climates. In addition, the composition from natural, renewable and biodegradable materials that are ecological advantages stands out. Keywords: bioclimatic architecture; sustainable architecture; passive air conditioning; Thermal comfort; thermal inertia; thermal simulation; construction system; thermal transmittance.   Recibido: febrero 25 / 2019  Evaluado: septiembre 20 / 2019  Aceptado: noviembre 23 / 2019 Publicado en línea: noviembre de 2019                               Actualizado: noviembre de 2019  


2021 ◽  
Vol 886 ◽  
pp. 213-227
Author(s):  
Soumia Mounir ◽  
Youssef Maaloufa ◽  
Khabbazi Abdelhamid ◽  
Khalid El Harrouni

Passive solutions in the concept of energy efficiency play an important role in reducing energy consumption, and emissions of CO2. However, controlling the parameters of walls, and roof thermal Inertia is the perfect way to ensure comfort inside houses. In this paper, an investigation of thermal inertia behavior, and energy efficiency of clay with natural, and industrial additives: cork, wool, and waste of plastic. The use of those materials will improve the comfort of the inhabitants of the cold area who suffer from the hard climatic conditions, not just the block’s clay will be extracted from the same area but also they will be sun backed, the thing which will reduce the huge energy consumption of brickyard. A study of the energy efficiency of those materials was done using TRNSYS, and an evaluation of their environmental impact was evaluated by calculating their emissions in terms of CO2. The results obtained indicate an important characteristic in term of thermal Inertia, for a value of thermal transmittance of U= 0.55 W.m-2.K-1, we need 0.9m thickness of wall using the heavy concrete, however, if we use clay, we gain 69 %, clay-plastic we gain 79 %, clay cork, we gain 87 %, and by clay-wool, we earn 89 % in term of the wall’s thickness. For the delay of the heat flow of a wall of 25 cm, we could assure a delay of above 11h instead of just 2h for the heavy concrete. Concerning the heating need during a year during the cold season, the clay presents a need for 1500 KJ.h-1. Concerning the footprint carbon, the composite clay-cork has a negative footprint carbon; however, the clay and clay-wool present a low carbon emission near zero when the clay-plastic and the heavy concrete present the highest value of emissions.


Author(s):  
Pablo Zanocco ◽  
Jose´ Gonzalez ◽  
Marcelo Gime´nez

In this work, a case of loss of heat removal, caused by a loss of electrical supply, is analyzed for Atucha II PHWR. This reactor is similar to a PWR reactor in many aspects, but differs because it has, inside the pressure vessel, vertical coolant channels inside a moderator tank, which is at primary system pressure but a lower temperature. During the studied event, moderator temperature rises, heated by primary system (acting as a heat sink), until the temperatures are equalized. Given that primary and moderator systems are interconnected, the expansion of the moderator produces a rise in the level in pressurizer. The main aspects of the plant dynamic in the presented case are shown and analyzed. The normal strategy of the plant to cope with this initiating event is also discussed: the systems involved, operational modes and trigger signals are described. Then, three possible sequences are studied: heat removal by steam generators or moderator heat exchangers, and black out (no heat removal). The safety functions required to cope with this initiating event are also determined, as long as the associated safety and auxiliary systems. Representative variables of selected sequences are shown, in order to go further in understanding of the plant behavior. The different final stages are identified. The minimum capability of each system, necessary to achieve a plant safe condition, is also established. It was found that in this particular event, their requirements are less than the ones specified in the design basis. Also the influence of moderator system thermal inertia on transients is determined as a distinctive characteristics of this reactor.


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