Possibility of Advanced Modified-Silica-Based Porous Materials Utilisation in Water Adsorption Processes—A Comparative Study

Due to a high risk of power outages, a heat-driven adsorption chillers are gaining the attention. To increase the efficiency of the chiller, new adsorbents must be produced and examined. In this study, four newly developed silica–based porous materials were tested and compared with silica gel, an adsorber commonly paired with water. Extended sorption tests using mercury intrusion porosimetry, gas adsorption, and dynamic vapor sorption were performed. The morphology of the samples was determined using a scanning electron microscope. The thermal properties were defined using simultaneous thermal analysis and a laser flash method. Metal organic silica (MOS) nanocomposites analysed in this study had thermal properties similar to those of commonly used silica gel. MOS samples have a thermal diffusivity coefficient in the range of 0.17–0.25 mm2/s, whereas silica gel of about 0.2 mm2/s. The highest water adsorption capacity was measured for AFSMo-Cu and equal to 33–35%. For narrow porous silica gel mass uptake was equal about 25%. In the case of water adsorption, it was observed that the pore size of the sorbent is essential, and adsorbents with pore sizes higher than 5 nm, are most recommended in working pairs with water.

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Determination of Thermal Diffusivity and Influence of Defect Structure in Alloys Based on the Fe-Al System

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.336.129 ◽

2013 ◽

Vol 336 ◽

pp. 129-134 ◽

Cited By ~ 1

Author(s):

E. Bernstock-Kopaczyńska ◽

Magdalena Jabłońska

Keyword(s):

High Temperature ◽

Thermal Diffusivity ◽

Defect Structure ◽

Thermal Characteristics ◽

Laser Flash ◽

Structural Defects ◽

Flash Method ◽

Aluminium Content ◽

Diffusivity Coefficient ◽

Thermal Diffusivity Coefficient

Alloys of the Fe-Al system are interesting due to occurrence of long-range order and many thermal vacancies at high temperature, which lead to not only significant hardening, but also cause changes of physical properties. High temperature diffusion is conditioned by structural defects in solids, such as vacancies, foreign atoms and dislocations influencing thermal characteristics of a solid solution, among others the thermal diffusivity coefficient. Measurement of thermal diffusivity was performed at room temperature using the laser flash method. For characterization of the defect structure, positron annihilation lifetime spectroscopy was used. The data were presented for alloys with 28 and 38 at.% aluminium without chromium and containing 5 at. % Cr addition. The results showed that thermal diffusivity decreased with aluminium content and deviation from stoichiometry. In the studies, different structural defects in the alloys were observed.

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Определение температуропроводности материалов методом нестационарного точечного нагрева

Письма в журнал технической физики ◽

10.21883/pjtf.2020.01.48863.18052 ◽

2020 ◽

Vol 46 (1) ◽

pp. 39

Author(s):

Д.Ю. Головин ◽

А.И. Тюрин ◽

А.А. Самодуров ◽

Ю.И. Головин

Keyword(s):

Thermal Diffusivity ◽

Laser Flash ◽

Processing Technique ◽

Flash Method ◽

Diffusivity Coefficient ◽

Thermal Camera ◽

Absorbed Energy ◽

Thermal Diffusivity Coefficient ◽

Data Processing Technique

Express thermographic method for measuring thermal diffusivity of thin flat objects is described in the paper. It could be considered as modification or a branch of laser flash method, however it does not require sample cutting or two side access to the object. The method comprises step-like heating of the small area (~ 0.1 mm2) at the object surface by focused laser beam and continuous recording temperature distribution at the surface by thermal camera. Developed data processing technique does not require information about absolute temperatures or absorbed energy for determination of thermal diffusivity coefficient.

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Thermal Characterization of Carbon-Carbon Composites

Volume 10: Heat and Mass Transport Processes, Parts A and B ◽

10.1115/imece2011-64061 ◽

2011 ◽

Author(s):

Messiha Saad ◽

Darryl Baker ◽

Rhys Reaves

Keyword(s):

Thermal Conductivity ◽

Thermal Properties ◽

Thermal Diffusivity ◽

Specific Heat ◽

Critical Role ◽

Carbon Composite ◽

Flash Method ◽

Carbon Composites ◽

Energy Storage Devices ◽

Graphitized Carbon

Thermal properties of materials such as specific heat, thermal diffusivity, and thermal conductivity are very important in the 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 and solar cells. Thermal conductivity plays a critical role in the performance of materials in high temperature applications. Thermal conductivity is the property that determines the working temperature levels of the material, and it is an important parameter in problems involving heat transfer and thermal structures. The objective of this research is to develop thermal properties data base for carbon-carbon and graphitized carbon-carbon composite materials. The carbon-carbon composites tested were produced by the Resin Transfer Molding (RTM) process using T300 2-D carbon fabric and Primaset PT-30 cyanate ester. The graphitized carbon-carbon composite was heat treated to 2500°C. The flash method was used to measure the thermal diffusivity of the materials; this method is based on America Society for Testing and Materials, ASTM E1461 standard. In addition, the differential scanning calorimeter was used in accordance with the ASTM E1269 standard to determine the specific heat. The thermal conductivity was determined using the measured values of their thermal diffusivity, specific heat, and the density of the materials.

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On analysis of thermodynamic properties of cuboctahedral bi-metallic structure

Main Group Metal Chemistry ◽

10.1515/mgmc-2021-0014 ◽

2021 ◽

Vol 44 (1) ◽

pp. 117-128

Author(s):

Muhammad Kamran Siddiqui ◽

Yu-Ming Chu ◽

Muhammad Nasir ◽

Murat Cancan

Keyword(s):

Thermodynamic Properties ◽

Porous Materials ◽

Gas Adsorption ◽

Topological Indices ◽

Metallic Structure

Abstract Porous materials, for example, metalnatural structures (MOFs) and their discrete partners metalnatural polyhedra (MOPs), that are built from coordinatively unsaturated inorganic hubs show incredible potential for application in gas adsorption/partition cycles, catalysis, and arising openings in hardware, optics, detecting, and biotechnology. A well-known hetero-bimetallic metalorganic polyhedra of this discrete partners metalnatural polyhedra (MOPs) class is cuboctahedral bi-metallic stricture. In this paper, we discuss the stricture of Hetero-bimetallic metalorganic polyhedra (cuboctahedral bi-metallic). Also, we computed the topological indices based on the degree of atoms in this cuboctahedral bi-metallic structure.

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Pump-probe photothermal lens experiment for measuring the thermal diffusivity coefficient of organic solvents

10.1117/12.794172 ◽

2008 ◽

Author(s):

A. Marcano O. ◽

N. Melikechi ◽

A. Zelinskas ◽

M. Benitez

Keyword(s):

Thermal Diffusivity ◽

Organic Solvents ◽

Diffusivity Coefficient ◽

Pump Probe ◽

Thermal Diffusivity Coefficient

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Monte Carlo Simulations for Water Adsorption in Porous Materials: Best Practices and New Insights

AIChE Journal ◽

10.1002/aic.17447 ◽

2021 ◽

Author(s):

Archit Datar ◽

Matthew Witman ◽

Li‐Chiang Lin

Keyword(s):

Monte Carlo ◽

Best Practices ◽

Monte Carlo Simulations ◽

Porous Materials ◽

Water Adsorption

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Study on Thermal Conductivity of Polyetheretherketone/Thermally Conductive Filler Composites

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.1079 ◽

2007 ◽

Vol 124-126 ◽

pp. 1079-1082 ◽

Cited By ~ 4

Author(s):

Sung Ryong Kim ◽

Dae Hoon Kim ◽

Dong Ju Kim ◽

Min Hyung Kim ◽

Joung Man Park

Keyword(s):

Thermal Conductivity ◽

Thermal Properties ◽

Carbon Fiber ◽

Conductive Filler ◽

Laser Flash ◽

Flash Method ◽

Phase System ◽

Two Phase ◽

Nielsen Theory ◽

Thermally Conductive

Thermal properties of PEEK/silicon carbide(SiC) and PEEK/carbon fiber(CF) were investigated from ambient temperature up to 200°C measured by laser flash method. Thermal conductivity was increased from 0.29W/m-K without filler up to 2.4 W/m-K with at 50 volume % SiC and 3.1W/m-K with 40 volume % carbon fiber. Values from Nielsen theory that predicts thermal conductivity of two-phase system were compared to those obtained from experiment.

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Thermochemical erosion and thermophysical properties of phenolic resin/carbon fiber/graphite nanocomposites

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684416669600 ◽

2016 ◽

Vol 35 (24) ◽

pp. 1814-1825 ◽

Cited By ~ 4

Author(s):

Samire Sabagh ◽

Ahmad Arefazar ◽

Ahmad Reza Bahramian

Keyword(s):

Carbon Fiber ◽

Thermophysical Properties ◽

Theoretical Calculations ◽

Reference Sample ◽

Nanocrystalline Powders ◽

Gravimetric Analysis ◽

Diffusivity Coefficient ◽

Thermal Diffusivity Coefficient ◽

Analysis Technique ◽

Short Carbon

The main objective of this work is an experimental investigation and an analytical modeling of ablation and to analyze the thermophysical properties of nanocomposites based on novolac resin/short carbon fiber/graphite nanocrystalline powders in oxyacetylene flame test. The composite consisting of 40 wt.% carbon fiber was prepared as reference sample of which matrix was modified with three different percentages (6, 9 and 12 wt.%) of nano-sized graphite powders as reinforcement. Ablation is calculated by mass balance equation. Some parameters in the ablation modeling are evaluated by simultaneous thermal gravimetric analysis technique. Results of this work show that ablation rates decrease by the addition of graphite powders. The theoretical ablation rates are 33–38% less than the experimental data analyzed by oxyacetylene flame tests. This difference is reasonable because the effect of fluid stream force of oxyacetylene flame that causes the thermomechanical erosion of the surface is omitted in theoretical calculations. Therefore the model only calculates thermochemical erosion. Also, the thermophysical properties change due to heating is analyzed. Moreover, in nanocomposite with 9 wt.% graphite nanopowders, the rate of ablation and thermal diffusivity coefficient decreased by 10% and 50%, respectively, and thermal stability increased by 12% compared to the reference sample.

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