scholarly journals Study of thermal properties on the different layers composing a commercial ceramic tile

2019 ◽  
Vol 65 (2) ◽  
pp. 124
Author(s):  
J. J. A. Flores Cuautle ◽  
G. Lara Hernandez ◽  
A. Cruz Orea ◽  
E. Suaste Gomez ◽  
C. Hernandez Aguilar ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Transfer ◽  
Thermal Properties ◽  
Ceramic Tile ◽  
Building Materials ◽  
Photothermal Techniques ◽  
Essential Factor ◽  
Wide Range ◽  
Thermal Insulations ◽  
Enamel Layer

In this study is determined the thermal conductivity of a commercial ceramic considering that this property on the building materials is an essential factor, and it is the primary indicator of the suitableness of the material in the energy transfer considering that this kind of materials has many applications as thermal insulations. In this sense and considering that a commercial tile is usually composed of three layers, a substrate, a so-called engobe layer, and an enamel layer. Likewise, the thermal properties of the different layers were obtained individually by using two photothermal techniques on the ceramic material; the ceramic tile density was obtained using the Archimedes method. The calculated values show a wide range of thermal conductivity values for the different layers, ranging from1.3 to 4 W m-1K-1. 

scholarly journals Testing a Gypsum Composite Based on Raw Gypsum with a Direct Admixture of Paraffin and Polymer to Improve Thermal Properties

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3241
Author(s):  
Krzysztof Powała ◽  
Andrzej Obraniak ◽  
Dariusz Heim
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Phase Change ◽  
Large Scale ◽  
Building Materials ◽  
Residential Buildings ◽  
Energy Performance ◽  
Polymer Content ◽  
Volumetric Heat Capacity

The implemented new legal regulations regarding thermal comfort, the energy performance of residential buildings, and proecological requirements require the design of new building materials, the use of which will improve the thermal efficiency of newly built and renovated buildings. Therefore, many companies producing building materials strive to improve the properties of their products by reducing the weight of the materials, increasing their mechanical properties, and improving their insulating properties. Currently, there are solutions in phase-change materials (PCM) production technology, such as microencapsulation, but its application on a large scale is extremely costly. This paper presents a solution to the abovementioned problem through the creation and testing of a composite, i.e., a new mixture of gypsum, paraffin, and polymer, which can be used in the production of plasterboard. The presented solution uses a material (PCM) which improves the thermal properties of the composite by taking advantage of the phase-change phenomenon. The study analyzes the influence of polymer content in the total mass of a composite in relation to its thermal conductivity, volumetric heat capacity, and diffusivity. Based on the results contained in this article, the best solution appears to be a mixture with 0.1% polymer content. It is definitely visible in the tests which use drying, hardening time, and paraffin absorption. It differs slightly from the best result in the thermal conductivity test, while it is comparable in terms of volumetric heat capacity and differs slightly from the best result in the thermal diffusivity test.

scholarly journals Modeling the Influence of Temperature-dependent Thermal Properties on the Freezing Front

2019 ◽  
Vol 8 (6) ◽  
pp. 129
Author(s):  
Victor M. Chavarria
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Statistical Error ◽  
Analytical Models ◽  
Parameter Estimates ◽  
Temperature Dependent ◽  
Freezing Front ◽  
Model Accuracy ◽  
Medium Temperature ◽  
Wide Range

Although numerical methods enable comprehensive analyses of food freezing, a thorough quantification is lacking the effects on the process introduced by uncertainties in variable thermal properties. Analytical models are, however, more suitable tools to perform such calculations. We aim to quantify these effects by developing a solution to the freezing front (FF) problem subject to temperature-dependent thermal properties and one-dimensional convective cooling. The heat integral balance method, Kirchhoff's transformation, and Plank's cooled-surface temperature equation (as a seed function) enabled us to obtain an approximate solution to the FF penetration time. To optimize model accuracy, two adjustable parameters were correlated with the inputs via nonlinear regression referenced to numerical simulation FF data. The mapped sensitivities, generated by perturbations in the temperature-dependent thermal conductivity and effective heat capacity, undergo rapid nonlinear changes for Biot numbers below 6. Above this level, these sensitivities stabilize depending on the cooling medium temperature and a thermal conductivity parameter. The median thermal conductivity-driven sensitivity is 0.348 and its interquartile range (IQR) is 0.220 to 0.425, whereas the median latent heat-driven sensitivity is 0.967 (IQR: 0.877 to 0.985). Statistical error measures and a ten-split K-fold validation support the model accuracy and reliability of the parameter estimates. Together, the model allows for gaining insights into the nonlinear behavior and magnitude of the influence of variable properties on the FF for a wide range of conditions. Nonlinear methods and prior information enable practical modeling of transport phenomena in foods.

Thermal Characterization of IM7/8552-1 Carbon-Epoxy Composites

2014 ◽  
Author(s):  
Messiha T. Saad ◽  
Sandi G. Miller ◽  
Torrence Marunda
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Carbon Fiber ◽  
Specific Heat ◽  
High Performance ◽  
Critical Role ◽  
Flash Method ◽  
Handling Characteristics ◽  
Wide Range

Thermal properties of composite materials such as, thermal conductivity, diffusivity, and specific heat are very important in engineering design process and analysis of aerospace vehicles as well as space systems. These properties are also important in power generation, transportation, and energy storage devices including fuel cells. Thermal conductivity is the property that determines the working temperature levels of the material; it plays a critical role in the performance of materials in high temperature applications, and it is an important parameter in problems involving heat transfer and thermal structures. The objective of this paper is to develop a thermal properties data base for the carbon fiber-epoxy (IM7/8552-1) composite. The IM7 carbon fiber is a continuous, high performance, intermediate modulus, PAN based fiber. This fiber has been surface treated and can be sized to improve its interlaminar shear properties, handling characteristics, and structural properties. The 8552 is a high performance tough epoxy matrix for use in primary aerospace structures. It exhibits good impact resistance and damage tolerance for a wide range of applications. The IM7/8552-1 is an amine cured unidirectional prepreg. The manufacturer recommended cure cycle for this material was followed, which includes consolidation under vacuum and autoclave pressure. The composite has a service temperature up to 121°C (250°F). The thermal properties of IM7/8552-1 carbon-epoxy have been investigated using experimental methods. The flash method was used to measure the thermal diffusivity of the composite. This method is based on the American Society for Testing and Materials standard, ASTM E1461. In addition, the Differential Scanning Calorimeter was used in accordance with the ASTM E1269 standard to measure the specific heat. The measured thermal diffusivity, specific heat, and density data were used to compute the thermal conductivity of the IM7/8552-1 carbon-epoxy composite.

scholarly journals Foams based on industrial waste

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Nadezhda Manakova
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Building Materials ◽  
Raw Materials ◽  
Foam Glass ◽  
Construction Materials ◽  
Economic Damage ◽  
Mining Areas ◽  
Wide Range ◽  
Microscopic Studies

Substantial volumes of tailings and waste rocks placed in dumps create serious environmental and economic damage in mining areas and adjacent territories. The development of technologies for processing waste into heat-insulating building materials (foam glass) will make it possible to reduce the burden on the environment, as well as reduce the cost of finished building products. The article substantiates the possibility of obtaining block foamed materials for the production of heat-insulating materials based on man-made waste using low-temperature technology. The author investigated the ways of improving the operational properties of foam silicates by introducing modifying additives (apatite-nepheline waste, fly ash). To obtain foam silicates based on silica-containing waste, a liquid glass composition was prepared, into which additives were introduced. After molding and drying, the samples were swollen. Physical, chemical and thermal properties of foamed silicate materials made of silica-containing raw materials were determined taking into account the requirements of GOST for thermal insulation construction materials. To determine the thermal conductivity coefficient, an ITP-MG 4 electronic thermal conductivity meter was used. Microscopic studies were carried out using a SEM LEO 420 scanning microscope. The author of the article proposes the optimal compositions and conditions for obtaining foam materials that meet the regulatory requirements for materials and products for building insulation. Foamed materials with density up to 0.55 g/cm3, strength 5.5 MPa, water absorption 15–22 %, thermal conductivity 0.09–0.104 W•m/K were obtained. Foam glass materials have a wide range of properties: non-flammable, environmentally friendly, have a long service life, and are not subject to mold deterioration. The obtained materials can be recommended for use as thermal insulation in the construction and reconstruction of industrial and civil buildings and structures.

Experimental Study of Thermal Conductivity of Insulation Materials Made of Expanded Polypropylene, Ethylene-Vinyl Acetate Co-Polymer and Polyethylene

2013 ◽  
Vol 831 ◽  
pp. 40-43 ◽  
Author(s):  
Young Sun Jeong ◽  
Ki Hyung Yu
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Thermal Properties ◽  
Heat Loss ◽  
Vinyl Acetate ◽  
Building Materials ◽  
Cell Structure ◽  
Ethylene Vinyl Acetate ◽  
Insulation Materials ◽  
Building Insulation

Thermal insulation materials are among the simplest ways of decreasing heat loss in the buildings. When insulation materials are installed in the walls, floors and roof of a building to prevent heat loss from the building, materials must be used with the appropriate structural and thermal properties. In this paper, a laboratory test of the thermal conductivity and cell structure of building insulation materials was conducted. From the experiment results, the correlation expression between thermal conductivity and density was derived. In the case of the insulation materials that were made of expanded polypropylene (EPP), as the density increased, the thermal conductivity tended to decrease; and in the case of ethylene-vinyl acetate co-polymer (EVA) and polyethylene (PE), as the density of the insulation materials increased, the thermal conductivity tended to also increase.

scholarly journals Thermal properties of cement mortar with different mix proportions

2020 ◽  
Vol 70 (339) ◽  
pp. 224 ◽  
Author(s):  
P. Shafigh ◽  
I. Asadi ◽  
A. R. Akhiani ◽  
N. B. Mahyuddin ◽  
M. Hashemi
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Cement Mortar ◽  
Construction Material ◽  
Physical And Mechanical Properties ◽  
Sem Images ◽  
Heating And Cooling ◽  
Wide Range

The energy required for the heating and cooling of buildings is strongly dependant on the thermal properties of the construction material. Cement mortar is a common construction material that is widely used in buildings. The main aim of this study is to assess the thermal properties of cement mortar in terms of its ther­mal conductivity, heat capacity and thermal diffusivity in a wide range of grades (cement: sand ratio between 1:2 and 1:8). As there is insufficient information to predict the thermal conductivity and diffusivity of a cement mortar from its physical and mechanical properties, the relationships between thermal conductivity and diffu­sivity and density, compressive strength, water absorption and porosity are also discussed. Our results indicate that, for a cement mortar with a 28-day compressive strength in the range of 6–60 MPa, thermal conductivity, specific heat and thermal diffusivity are in the range of 1.5–2.7 W/(m.K), 0.87–1.04 kJ/kg.K and 0.89–1.26 (x10-6 m2/s), respectively. The scanning electron microscope (SEM) images showed that pore size varied from 18 μm to 946 μm for samples with different cement-to-sand ratios. The porosity of cement mortar has a signifi­cant effect on its thermal and physical properties. For this reason, thermal conductivity and thermal diffusivity was greater in cement mortar samples with a higher density and compressive strength.

scholarly journals Influence of Silica-Aerogel on Mechanical Characteristics of Polyurethane-Based Composites: Thermal Conductivity and Strength

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1790
Author(s):  
Jeong-Hyeon Kim ◽  
Jae-Hyeok Ahn ◽  
Jeong-Dae Kim ◽  
Dong-Ha Lee ◽  
Seul-Kee Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Cell Morphology ◽  
Environmental Conditions ◽  
Silica Aerogel ◽  
Porous Silica ◽  
Mechanical And Thermal Properties ◽  
Insulation Material ◽  
Wide Range ◽  
Insulation Systems

Polyurethane foam (PUF) has generally been used in liquefied natural gas (LNG) carrier cargo containment systems (CCSs) owing to its excellent mechanical and thermal properties over a wide range of temperatures. An LNG CCS must be designed to withstand extreme environmental conditions. However, as the insulation material for LNGC CCSs, PUF has two major limitations: its strength and thermal conductivity. In the present study, PUFs were synthesized with various weight percentages of porous silica aerogel to reinforce the characteristics of PUF used in LNG carrier insulation systems. To evaluate the mechanical strength of the PUF-silica aerogel composites considering LNG loading/unloading environmental conditions, compressive tests were conducted at room temperature (20 °C) and a cryogenic temperature (−163 °C). In addition, the thermal insulation performance and cellular structure were identified to analyze the effects of silica aerogels on cell morphology. The cell morphology of PUF-silica aerogel composites was relatively homogeneous, and the cell shape remained closed at 1 wt.% in comparison to the other concentrations. As a result, the mechanical and thermal properties were significantly improved by the addition of 1 wt.% silica aerogel to the PUF. The mechanical properties were reduced by increasing the silica aerogel content to 3 wt.% and 5 wt.%, mainly because of the pores generated on the surface of the composites.

Recycling and Reuse in the Roman Economy

2020 ◽  
Keyword(s):  
Building Materials ◽  
Computational Modelling ◽  
Late Antique ◽  
Roman Economy ◽  
Wide Range ◽  
The Status ◽  
Recent Developments ◽  
Methodological Approaches ◽  
First Time ◽  
Site Types

The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.

Sign in / Sign up

Export Citation Format

Share Document