Статті в журналах: "Elasticity and Thermal Conductivity"

1

Wang, Xiao Hua, and Ming Nie. "Properties of PANI-PVA Composite Film." Advanced Materials Research 284-286 (July 2011): 253–56. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.253.

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The polyaniline(PANI)-poly(vinyl alcoho1)(PVA) composite film doped with HC1 was prepared with PVA as matrix. Effects of PVA content, film drying temperature on properties of PANI-PVA composite film were studied. Tensile strength, elasticity, conductivity and thermal stability of PVA, HC1-PANI or PANI-PVA were compared. Tensile strength and elasticity of PVA film were the largest, its conductivity was the least. The conductivity of PANI-PVA was the largest, tensile strength and elasticity of PANI-PVA are bigger than those of HC1-PANI. The order of their thermal stability is PVA> HC1-PANI > PANI-PVA before 260°C, the order of their thermal stability is HC1-PANI>PANI-PVA> PVA after 260°C.

2

Chifor, Victoria, Radu Liviu Orban, Zafer Tekiner, and Mehmet Turker. "Mechanical, Thermal and Electrical Properties of Acrilonitril Butadiene Styrene (ABS) Composites Filled with Bronze Powder." Materials Science Forum 672 (January 2011): 179–82. http://dx.doi.org/10.4028/www.scientific.net/msf.672.179.

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This article reports on an experimental study of the mechanical, thermal and electrical properties of bronze-ABS composites containing 5, 10, 20, 30 vol.% of bronze powder. The mechanical properties such as ultimate tensile strength, elongation at fracture, modulus of elasticity, melt flow rate (MFR), hardness, thermal conductivity, electrical conductivity of bronze powder filler embedded in a ABS matrix were experimentally investigated. Thermal and electrical conductivity measurements were performed up to a filler concentration of 30 vol.%. The tensile strength, elongation, MFR values continuously decreased with increasing the bronze powder content. However, modulus of elasticity and hardness increased with increasing the bronze content. Thermal and electrical conductivity of the composites was found to be higher for ABS-20 vol.% bronze composites than that of the other composites.

3

Chifor, Victoria, Radu Liviu Orban, Zafer Tekiner, and Mehmet Turker. "Thermal, Mechanical and Electrical Properties of High Density Polyethylene Composites Reinforced with Copper Powder." Materials Science Forum 672 (January 2011): 191–94. http://dx.doi.org/10.4028/www.scientific.net/msf.672.191.

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The thermal conductivity, electrical conductivity and mechanical properties such as tensile strength, elongation, modulus of elasticity, were experimentally investigated. Thermal and electrical conductivity measurements were performed up to filler concentration of 30 vol.%. The mechanical properties of high density polyethylene filled with up to 30 vol.% Cu particles were investigated. The tensile strength, elongation and toughness decreased with increasing Cu powder content. This was attributed to the introduction of discontinuities in the polymer structure in which modulus of elasticity increased with increasing the copper content.

4

Li, Gong Fa, Si Qiang Xu, Guo Zhang Jiang, Ze Hao Wu, Jian Yi Kong, and Liang Xi Xie. "Influence of Working Lining Parameters on Stress Field of Ladle Composite Construction Body." Applied Mechanics and Materials 121-126 (October 2011): 800–804. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.800.

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The ladle is an important equipment of the metallurgical industry. Distribution of thermomechanical stress in linings has an essential influence on its life, and the size of its life-span influences the economic benefits of the iron and steel enterprise directly. Two-dimensional model of ladle based on law of finite element method is built, and the influence of thermal conductivity, thermal expansion coefficient, elasticity coefficient and thickness of work lining on ladle stress field are discussed. The calculation results indicate that stress increases with the increase of thermal conductivity, thermal expansion coefficient and elasticity coefficient and decrease of thickness.

5

Oginni, Felix A., and Samuel N. John. "Some Engineering Properties of Foamed Concrete for Sustainable Technological Development." European Journal of Engineering and Technology Research 6, no. 3 (March 31, 2021): 53–57. http://dx.doi.org/10.24018/ejers.2021.6.3.2396.

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A study of the technology of foamed concrete production is carried out. The engineering properties and applications of this type of concrete are presented for varying densities so as to effectively tap the advantages of its use for specific purposes. The properties considered are the 7-day compressive strength, thermal conductivity, modulus of elasticity and drying shrinkage. A study of the behaviours of foamed concrete at varying dry densities for the different characteristics was undertaken. Results indicate that as the dry density increases, the engineering properties increase though at different rates for the 7-day Compressive strength, Thermal conductivity, and Modulus of elasticity. The drying shrinkage decreases as the dry density increases. A comparative study of the 7-day Compressive strength and Modulus of elasticity show that they both follow the same trend over the varying dry density except at a dry density of 1200 kg/m3. A comparative study of the thermal conductivity and the percent drying shrinkage indicate that the thermal conductivity is inversely proportional to the percent drying shrinkage. Economics and other considerations together with its multipurpose applications of foamed concrete can open up business opportunities in Africa and sustainability. This can also help in providing needed funds for infrastructural development.

6

Oginni, Felix A., and Samuel N. John. "Some Engineering Properties of Foamed Concrete for Sustainable Technological Development." European Journal of Engineering and Technology Research 6, no. 3 (March 31, 2021): 58–62. http://dx.doi.org/10.24018/ejeng.2021.6.3.2396.

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A study of the technology of foamed concrete production is carried out. The engineering properties and applications of this type of concrete are presented for varying densities so as to effectively tap the advantages of its use for specific purposes. The properties considered are the 7-day compressive strength, thermal conductivity, modulus of elasticity and drying shrinkage. A study of the behaviours of foamed concrete at varying dry densities for the different characteristics was undertaken. Results indicate that as the dry density increases, the engineering properties increase though at different rates for the 7-day Compressive strength, Thermal conductivity, and Modulus of elasticity. The drying shrinkage decreases as the dry density increases. A comparative study of the 7-day Compressive strength and Modulus of elasticity show that they both follow the same trend over the varying dry density except at a dry density of 1200 kg/m3. A comparative study of the thermal conductivity and the percent drying shrinkage indicate that the thermal conductivity is inversely proportional to the percent drying shrinkage. Economics and other considerations together with its multipurpose applications of foamed concrete can open up business opportunities in Africa and sustainability. This can also help in providing needed funds for infrastructural development.

7

Belova, Irina V., Graeme E. Murch, Thomas Fiedler, and Andreas Öchsner. "Lattice-Based Walks and the Monte Carlo Method for Addressing Mass, Thermal and Elasticity Problems." Defect and Diffusion Forum 283-286 (March 2009): 13–23. http://dx.doi.org/10.4028/www.scientific.net/ddf.283-286.13.

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In this paper, we review the recent developed method based around lattice-based random walks and the Monte Carlo method. This method, which is now called the Lattice Monte Carlo method, permits complex phenomenological problems in diffusion, thermal conductivity and elasticity to be addressed. It is shown how the effective mass diffusivity, thermal diffusivity/thermal conductivity and the bulk modulus in composites can be calculated and also how concentration profiles and temperature profiles can be determined in situations where the diffusivity depends on position and concentration and the thermal conductivity depends on position and temperature respectively.

8

Li, Guan-Nan, Zhi-Qian Chen, Yu-Ming Lu, Meng Hu, Li-Na Jiao, and Hao-Ting Zhao. "Elasticity, slowness, thermal conductivity and the anisotropies in the Mn3Cu1−xGexN compounds." International Journal of Modern Physics B 32, no. 07 (March 5, 2018): 1850071. http://dx.doi.org/10.1142/s0217979218500716.

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We perform the first-principles to systematically investigate the elastic properties, minimum thermal conductivity and anisotropy of the negative thermal expansion compounds Mn3Cu[Formula: see text]Ge[Formula: see text]N. The elastic constant, bulk modulus, shear modulus, Young’s modulus and Poisson ratio are calculated for all the compounds. The results of the elastic constant indicate that all the compounds are mechanically stable and the doped Ge can adjust the ductile character of the compounds. According to the values of the percent ratio of the elastic anisotropy A[Formula: see text], A[Formula: see text] and A[Formula: see text], shear anisotropic factors A1, A2 and A3, all the Mn3Cu[Formula: see text]Ge[Formula: see text]N compounds are elastic anisotropy. The three-dimensional diagrams of elastic moduli in space also show that all the compounds are elastic anisotropy. In addition, the acoustic wave speed, slowness, minimum thermal conductivity and Debye temperature are also calculated. When the ratio of content for Cu and Ge arrived to 1:1, the compound has the lowest thermal conductivity and the highest Debye temperature.

9

Mohan Krishna, S. A., K. B. Vinay, B. C. Ashok, G. V. Naveen Prakash, and B. S. Nithyananda. "Experimental and numerical investigations on thermal expansion and thermal conductivity properties of Al 6061-SIC-GR hybrid metal matrix composites." International Journal of Computational Materials Science and Engineering 10, no. 01 (March 2021): 2150002. http://dx.doi.org/10.1142/s2047684121500020.

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In this research paper, the determination of thermal expansivity and thermal conductivity has been accomplished for Al 6061, Silicon Carbide and Graphite hybrid metal matrix composites from room temperature to [Formula: see text]C. Aluminium-based composites reinforced with Silicon Carbide and Graphite particles have been prepared by stir casting technique. The thermal expansion and thermal conductivity properties of hybrid composites with different percentage compositions of reinforcements have been investigated. The results have indicated that the thermal expansivity and thermal conductivity of the different compositions of hybrid MMCs decrease by the addition of Graphite with Silicon Carbide and Al 6061. Few empirical models have been validated for the evaluation of thermal expansivity and thermal conductivity of hybrid composites. Using the experimental values, namely modulus of elasticity, Poisson ratio and thermal expansivity, computational investigation has been carried out to evaluate the thermal parameters, namely thermal displacement, thermal strain and thermal stress. Similarly, using the experimental values, namely density, thermal conductivity, specific heat capacity and enthalpy at varying temperature ranges, computational investigation has been carried out to evaluate thermal gradient and thermal flux.

10

Piat, Romana, and Yuriy Sinchuk. "Thermal Conductivity Design for Locally Orthotropic Materials." Key Engineering Materials 577-578 (September 2013): 437–40. http://dx.doi.org/10.4028/www.scientific.net/kem.577-578.437.

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In this paper the development of a computational model for the thermal conductivity design for locally orthotropic materials is presented. The material orientation of a two-dimensional locally orthotropic solid subjected to thermal loads is designed for minimization of the local temperature. Two optimization problems are considered: the minimization of the highest (hot-spot) temperature and the minimization of the temperature according to the weights distribution. For both problems rules for calculation of the optimal material orientation are derived analytically. The analysis is based on the idea of the principal stresses method for optimization of material orientation in linear elasticity problems. The results of the analysis are implemented and the developed computational model is tested on an example of the lamella orientation optimization in a metal-ceramic composite.

11

Lv, Hua Nan, Xiao Liang Zhang, Peng Zhao Gao, Dong Yun Li, Wen Xie, and Han Ning Xiao. "Influence of Density on the Microstructure, Mechanical, Electrical and Thermal Properties of Recrystallized Silicon Carbide." Key Engineering Materials 680 (February 2016): 93–98. http://dx.doi.org/10.4028/www.scientific.net/kem.680.93.

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In this paper, influence of density on the microstructure, mechanical properties, thermal and electrical properties of recrystallized silicon carbide (RSiC) were investigated via XRD, SEM, mechanical test, thermal conductivity instrument and four-probe method, etc. The results showed that the main phase of the RSiC materials was 6H-SiC; The flexural strength and modulus of elasticity of RSiC materials increased with the increase of densities, and the flexural strength of it measured at 1400 °C increased about 10%-15% compared with that of at room temperature, while the modulus of elasticity at 1400°C were lower than that of at room temperature, resulting from the weakening of binding force between the Si and C atoms at high temperature; With the increase of temperatures, the thermal conductivity of the RSiC materials decreased, while it increased with the increase of RSiC density, when density of RSiC equaled to 2.60 g·cm3, values of the thermal conductivity were 177.7 W·(m·K)1 (RT) and 28.1 W·(m·K)1(1300°C), respectively; The volume resistivity of RSiC materials dropped from 12.74 Ω·cm to 4.51 Ω·cm as the density of RSiC increased, the impurities played an more important role on this variety.

12

Ao, Jing, Qun Hui, Chun-mei Li, Feng Li, and Zhi-qian Chen. "Anisotropies of elasticity and thermal conductivity in some novel superhard materials." Computational Materials Science 88 (June 2014): 103–9. http://dx.doi.org/10.1016/j.commatsci.2014.03.009.

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13

Ding, Yingchun, Min Chen, Wenjuan Wu, and Ming Xu. "Elasticity, Hardness and Thermal Conductivity of Si-Ge-Based Oxynitrides (SiGeN2O)." Journal of Electronic Materials 46, no. 1 (September 12, 2016): 510–19. http://dx.doi.org/10.1007/s11664-016-4915-5.

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14

Zhong, Yuan, Zhaofeng Zhou, and Canghao Ni. "Porosity resolved elasticity, thermal conductivity and stability of the foamed materials." Journal of Porous Materials 23, no. 5 (May 9, 2016): 1389–94. http://dx.doi.org/10.1007/s10934-016-0198-8.

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15

Liu, Zi-Jiang, Jia-Qi Ju, Xi-Long Dou, Neng-Zhi Jin, Cai-Rong Zhang, Xiao-Yun Wang, and Liang Wu. "Study on the structure, elasticity, and thermal conductivity of orthocarbonate Sr2CO4." Results in Physics 61 (June 2024): 107801. http://dx.doi.org/10.1016/j.rinp.2024.107801.

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16

Sabar, Dhilal Amer, and Fadhil K. Farhan. "Heat Transfer and Thermal Expansion of Coefficient EP -(MWCNT/x-TiO2)Nanocomposites." Journal of Engineering 24, no. 8 (July 28, 2018): 29. http://dx.doi.org/10.31026/j.eng.2018.08.03.

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The thermal properties (thermal transfer and thermal expansion coefficient) of the enhanced epoxy resin (MWCNT / x-TiO2) were studied by weight ratios with the values (0%, 3%, 5%, 7% and 10%) and a constant ratio of 3% of MWCNT. The ultrasonic technology was used to prepare the neat and composites which were then poured into Teflon molds according to standard conditions. Thermo-analyzer sensor technology was used to measure thermal transfer (thermal conductivity, thermal flow, thermal diffusion, thermal energy and heat resistance). The thermal conductivity, flow, and thermal conductivity values were increased sequentially by increasing the weight ratio of the filler while the results of stored energy values and thermal resistance decreased by increasing the percentage of salts. The thermal mechanical analysis was used to measure thermal expansion and elasticity coefficient. The scanning electron microscopy was used to interpret the results of thermal analysis and distribution of the nanoparticle within the polymer matrix.

17

Sharma, Neeraj Kumar, S. N. Pandit, and Rahul Vaish. "Microstructural Modeling of Ni-Al2O3 Composites Using Object-Oriented Finite-Element Method." ISRN Ceramics 2012 (October 15, 2012): 1–6. http://dx.doi.org/10.5402/2012/972054.

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This paper studied the mechanical and thermal properties of interpenetrating phase composites (IPCs) of Ni-Al2O3 using finite-element-based object-oriented program (OOFEM). It is difficult to model structure-property relationship in IPCs because of interpenetration of two or more phases. In order to understand the material behavior, OOFEM combines the microstructural data in the form microscopic images with the fundamental material properties (such as Young’s modulus or thermal conductivity of the constituent phases). Thermal conductivity, thermal expansion coefficient, and modulus of elasticity for the composites are examined using OOFEM and compared with other methods. The distribution of residual thermal stresses is also investigated.

18

Sinitsyn, Anton, Ludmila Voropay, Regina Salikhova, and Olga Yukhtarova. "Relationship between operational properties of peat heat-insulating materials and the content of mineral binders in them." E3S Web of Conferences 178 (2020): 01047. http://dx.doi.org/10.1051/e3sconf/202017801047.

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This work presents the main results of calculation and experimental study on relation between the operational properties of peat heat-insulating materials (HIM) and the content of mineral binders in them aiming at reducing heat energy costs by energy-consuming objects. It was experimentally proved that introduction of cement increases thermal conductivity, and introduction of calcium oxide as a mineral binder, on the contrary, promotes the development of material porosity while maintaining strength characteristics and elasticity and helps to reduce the thermal conductivity and specific density. The established relationship between the content of calcium oxide and the thermal conductivity enables modelling of technology for HIM producing based on peat and inorganic binders.

19

Journal, Baghdad Science. "Mechanical and Thermal Properties of Epoxy-Graphite Composites." Baghdad Science Journal 12, no. 1 (March 1, 2015): 40–45. http://dx.doi.org/10.21123/bsj.12.1.40-45.

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This search study the effect of particle size of graphite on the mechanical and thermal properties of epoxy composites, where graphite adopted with particle sizes (45,53,75) ?m, respectively, and the percentages by weight (0,1,3,5,7,9)% for each size of this three particle sizes.Mechanical properties represented by the bending (three-point bending) and through which the conclusion is bending stress and modulus of elasticity, thermal properties were either through thermal conductivity tests.The results showed that the ratio(1%) is the maximum value of bending stress at the three particle size and the (45 ?m) is the maximum.Thermal conductivity result show is the maximum value at ratio (1%) of particle size(53 ?m)

20

Al-rawi, Khalid R., and Noor Husian Majeed. "Mechanical and Thermal Properties of Epoxy-Graphite Composites." Baghdad Science Journal 12, no. 1 (March 1, 2015): 40–45. http://dx.doi.org/10.21123/bsj.2015.12.1.40-45.

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This search study the effect of particle size of graphite on the mechanical and thermal properties of epoxy composites, where graphite adopted with particle sizes (45,53,75) ?m, respectively, and the percentages by weight (0,1,3,5,7,9)% for each size of this three particle sizes.Mechanical properties represented by the bending (three-point bending) and through which the conclusion is bending stress and modulus of elasticity, thermal properties were either through thermal conductivity tests.The results showed that the ratio(1%) is the maximum value of bending stress at the three particle size and the (45 ?m) is the maximum.Thermal conductivity result show is the maximum value at ratio (1%) of particle size(53 ?m)

21

Feng, J., Z. C. Huang, R. Zhou, and W. Pan. "Anisotropic Mechanical and Thermal Properties of Nd₂SrAl₂O₇." Key Engineering Materials 512-515 (June 2012): 975–79. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.975.

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For a long time since the anisotropy basically confined to a single crystal, used as a polycrystalline ceramic materials generally considered to be isotropic. In this paper, the anisotropic mechanical, thermal expansion coefficient and thermal conductivity of a double perovskite slab-rocksalt layer Nd2SrAl2O7 was studied by first principles as an example. The method is using density functional theory (DFT) and crystal parameters, which has been used to calculate the modulus of elasticity of anisotropic in a three-dimensional space. While combined with traditional thermal conductivity theory, we have obtained the tensor of thermal diffusion, thermal conductivity in 3D space for the first time in the world within no. The results are in good agreement with the experiment. The advantage of method is avoiding the difficulty of experimental measurement, reducing the time and obtaining relatively accurate results.

22

Malisic, Vanja, Natasa Tomic, Marija Vuksanovic, Bojana Balanc, Zoran Stevic, Aleksandar Marinkovic, Radmila Jancic-Heinemann, and Slavisa Putic. "An experimental study of mechanical properties and heat transfer of acrylic composites with structural and surface modified Al2O3 particles." Science of Sintering 52, no. 4 (2020): 457–67. http://dx.doi.org/10.2298/sos2004457m.

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Thermal properties of acrylate-based composite combined with alumina-based particles were investigated. The composites were made of poly (methyl methacrylate) (PMMA) modified with dimethyl itaconate (DMI) as a matrix. Neat alumina particles (Al2O3) and alumina doped with iron oxide (Al2O3-Fe) modified with 3-aminopropyl-trimethoxylane (AM) and flax oil fatty acid methyl esters (biodiesel - BD) were used as reinforcement. Thermal conductivity measurements showed that composite with alumina particles with the highest alpha phase content had the highest thermal conductivity values. Mechanical properties (tensile strength, modulus of elasticity and elongation at break) were improved by the addition of modified alumina particles to PMMA/DMI matrix. The thermal properties are the most improved for composite with 3 wt.% Al2O3-Fe-AM particles that had the lowest temperature in a crack zone was noticed (10.28 %) compared to PMMA added due to the better stiffness and highest thermal conductivity.

23

Humaish, Hussein, and . "The Effect of Magnitude and Direction of Heat Flow on the Thermal Conductivity for Insulation Materials (Glass Wool) by Using Probe Method." International Journal of Engineering & Technology 7, no. 4.20 (November 28, 2018): 536. http://dx.doi.org/10.14419/ijet.v7i4.20.26414.

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The thermal energy of building is determined by the thermal properties of the materials and how to install these materials in the elements of buildings according to the direction of heat transfer. The effectiveness of thermal insulation (glass wool) is dependent on its thermal conductivity which is varies in different directions of fibers of glass wool. Glass wool is formed of fibers and binders tangled together during the industrial process to provide some elasticity. The experimental values of thermal conductivity of the insulation materials are changed according to magnitude of the heat power and direction of fiber arrangement. The thermal conductivity for insulation materials has been measured by using probe method, Huekseflux ® TP02 used to measure the thermal conductivity by emit the flow perpendicular and parallel to the fibers of glass wool. Two samples of yellow glass wool (density 68 kg/m3) with dimensions (10 ×10 ×30) cm have been used. Hot Disk bulk isotropic module has been used to evaluate thermal conductivity. TPS source (Hot Disk probe reference: 4922) characterized by a diameter of 14.61 mm has been selected. COMSOL® multiphysics axisymmetric 2D model has been used to follow the axial and the radial directions of the heat transfer.

24

Salifu, Smith, and Peter Apata Olubambi. "Thermomechanical properties prediction of wood-flour reinforced polymer composites using representative volume element (RVE)." MATEC Web of Conferences 370 (2022): 03002. http://dx.doi.org/10.1051/matecconf/202237003002.

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The accurate prediction of the thermomechanical properties of newly developed polymer composites is important in the determination of their possible areas of application. In this study, a 3D model of representative volume element (RVE) with different wood flour weight ratios (5, 10, 15, 20, 25 and 30 %) was used to develop wood flour polymer composites. Micromechanical material modelling software (Digimat) was used in conjunction with finite element analysis software (Abaqus) to develop the polymer composites and to determine their thermomechanical properties (modulus of elasticity, Poisson’s ratio, thermal conductivity, density, and hardness). The hardness, tensile strength and modulus of elasticity increase with an increase in the wt.% of wood flour, while the Poisson ratio, thermal conductivity and density decrease with an increase in the wt.% of wood flour. Also, the predicted thermomechanical properties using the micromechanical material modelling software (RVE) follow the same trend as those found in the literature.

25

Sun, Zhan, Huitao Yu, Can Chen, Mengmeng Qin, and Wei Feng. "Core-sheath smart polymer fiber composites with high elasticity and thermal conductivity." Composites Science and Technology 252 (June 2024): 110610. http://dx.doi.org/10.1016/j.compscitech.2024.110610.

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26

Yu, Jing, Yongmei Zhang, Yuhong Zhao, and Yue Ma. "Anisotropies in Elasticity, Sound Velocity, and Minimum Thermal Conductivity of Low Borides VxBy Compounds." Metals 11, no. 4 (April 1, 2021): 577. http://dx.doi.org/10.3390/met11040577.

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Anisotropies in the elasticity, sound velocity, and minimum thermal conductivity of low borides VB, V5B6, V3B4, and V2B3 are discussed using the first-principles calculations. The various elastic anisotropic indexes (AU, Acomp, and Ashear), three-dimensional (3D) surface contours, and their planar projections among different crystallographic planes of bulk modulus, shear modulus, and Young’s modulus are used to characterize elastic anisotropy. The bulk, shear, and Young’s moduli all show relatively strong degrees of anisotropy. With increased B content, the degree of anisotropy of the bulk modulus increases while those of the shear modulus and Young’s modulus decrease. The anisotropies of the sound velocity in the different planes show obvious differences. Meanwhile, the minimum thermal conductivity shows little dependence on crystallographic direction.

27

Majeed, Mohammed, and Suad H. Aleabi. "Enhancing Some Mechanical Properties (Compression, Impact, Hardness, Young modulus) and Thermal Conductivity, Diffusion Coefficient of Micro Epoxy Composites." Ibn AL-Haitham Journal For Pure and Applied Sciences 35, no. 3 (July 20, 2022): 32–43. http://dx.doi.org/10.30526/35.3.2841.

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In this research, the study effect of additive titanium dioxide powder (TiO2) as a lone composite ( Ep+TiO2) and a mixture of (TiO2) and silicon oxide (SiO2), ( Ep+ TiO2+SiO2)as a hybrid composite on the mechanical and physical properties for epoxy coating. Thescompsiteswere prepared by (Hand Lay- the molding) method. The samples were tested for compressive strength, surface hardness, modulus of elasticity, thermal conductivity and diffusion coefficient, from the results obtained showed improvement in mechanical properties after adding ceramic powders, as the alone composite (EP+ TiO2) had the highest compressive strength ( 53.738 ) ᴍPa, the hybrid composite ( EP+TiO2 +SiO2 ) had the highest surface hardness (79.65), modulus of elasticity (1166.66 ) ᴍPa, impact strength ( 8.48) ᴍPa, thermal conductivity (0.4961 )watt/ m.c◦. As for the diffusion coefficient in the acidic solution ( HCL), the epoxy without adding the highest diffusion coefficient ( 31.3x 10-10) m2/ sec while for immersion in ordinary water, the one composite material (Ep+ TiO2) had the highest value of the diffusion coefficient (7.56x10-10)m2/sec.

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B. S. Okrepkyi and M. Y. Shelestovska. "A circular stamp contactly communicates with a layer of a non-ideal thermal contact." Science and Transport Progress, no. 39 (December 25, 2011): 110–17. http://dx.doi.org/10.15802/stp2011/6884.

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Solution of the axis-symmetric contact task of thermo-elasticity of the hot cylinder circular punch stress on the elastic isotropic layer taking into account a non-ideal heat contact between punch and layer is built. Formulas for determination of the temperature field and normal stress in the contact area are obtained. The effect of the contact elasticity on the temperature and normal stress distribution is investigated. Investigation was made on the influence of the contact conductivity on distributing of the temperature fields and normal stress in the area of contact of two bodies.

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Dündar, Türker, Şeref Kurt, Nusret As, and Burhanettin Uysal. "Nondestructive evaluation of wood strength using thermal conductivity." BioResources 7, no. 3 (June 12, 2012): 3306–16. http://dx.doi.org/10.15376/biores.7.3.3306-3316.

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Relationships between the coefficient of thermal conductivity (CTC) and the strength properties of wood were investigated. Small clear test specimens were prepared from beech, fir, and pine wood. CTC values of the test specimens were measured based on the ASTM C 1113-99 hot-wire method. Wood density and some mechanical properties were then determined according to related ISO standards. In order to designate relationships between the CTC and mechanical properties, linear regression analysis was performed. Significant linear correlations were found between the CTC and the specific gravity, the modulus of rupture, the modulus of elasticity, and the impact bending strength of the wood from all tree species. However, there was a weak and non-significant relationship between the CTC and the compression strength of the specimens from each tree species. As a consequence, the CTC has a considerable potential in nondestructive evaluation of wood density and strength. However, the reciprocal correlations among the MC-strength, MC-CTC, temperature-strength, and temperature-CTC appear to be most significant limitations for using CTC as a NDE method for wood. Further detailed investigations are needed.

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Han, Seong-Sik, Hyun-jin Eom, Min-Su Lee, Tai-Hong Yim, and Heung-Kyu Kim. "Design of wood-like metallic material using metal sheet architecture." Journal of Computational Design and Engineering 8, no. 5 (September 11, 2021): 1290–306. http://dx.doi.org/10.1093/jcde/qwab048.

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Abstract This study proposed a new metal-based material design with a modulus of elasticity and thermal conductivity comparable to that of wood by architecturing of metal sheets. The proposed new material is designed in a form in which metal sheets of the same shape with beads are repeatedly stacked. In order to find a design with the target modulus of elasticity and thermal conductivity values, designs were derived using the Design of Experiment (DOE) and the material properties were predicted accordingly. For the prediction of material properties designed in the shape of a metal sheet architecture, finite element analysis combined with the homogenization method was used in consideration of the repeatability of the material microstructure. The reliability of the prediction of material properties based on the finite element analysis using a unit cell was verified by comparison with the results obtained from the compression test and the temperature wave method for the specimen. By analysing the modulus of elasticity and thermal conductivity data corresponding to the designs derived by DOE, we evaluated the effect of the design variables of the metal sheet architecture on the material properties. In addition, we investigated whether the material properties comparable to wood or leather were included within the derived design domain, and presented detailed design data of a metal sheet architecture that provides targeted material properties. It can be inferred from this study that the use of architecturing of metal sheets enables the development of new metal-based materials that can simulate the properties of other materials while utilizing the advantages of fire resistance and recyclability inherent in metals.

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Forero, Javier A., Miguel Bravo, João Pacheco, Jorge de Brito, and Luís Evangelista. "Thermal Performance of Concrete with Reactive Magnesium Oxide as an Alternative Binder." Sustainability 14, no. 10 (May 12, 2022): 5885. http://dx.doi.org/10.3390/su14105885.

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This study evaluates the thermal conductivity of concrete produced with reactive magnesium oxide (MgO) as a partial replacement for cement. MgO is a viable option for the concrete industry, mainly due to its benefits in sustainability and reducing CO2 emissions compared to cement emissions. Four different MgO’s produced in Australia, Canada, and Spain were used in concrete mixes as a partial replacement of cement at 5%, 10%, and 20% by mass. The experimental results showed that the thermal conductivity is higher when MgO increases in mixes after 28 days of curing. With the incorporation of MgO, the thermal conductivity increased between 3.2% and 10.2%, and the mechanical properties declined: compressive strength between 12.7% to 26.2%, splitting tensile strength between 9.7% to 34.0%, and modulus of elasticity between −4.1% to 7.8%. Finally, it is important to highlight that the addition of different contents of MgO in the concrete mixes modified the microstructure of the cement matrix. As a result, there was an increase in porosity, which negatively influenced the mechanical properties and thermal conductivity. Therefore, the relationships between these properties were also analyzed.

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Alves, Cleidson, Fernando Pelisser, João Labrincha, and Rui Novais. "Effect of Hydrogen Peroxide on the Thermal and Mechanical Properties of Lightweight Geopolymer Mortar Panels." Minerals 13, no. 4 (April 12, 2023): 542. http://dx.doi.org/10.3390/min13040542.

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Lightweight geopolymers have been researched and used in specific applications due to their differentiated properties and, particularly, due to the lower environmental impacts in their manufacture, mainly associated with the use of raw materials with a low environmental impact and the reduction in greenhouse gas emissions. In this study, light geopolymers, using metakaolin, sodium silicate, sodium hydroxide, and hydrogen peroxide (H2O2), were evaluated. The effects of H2O2 concentration were evaluated up to a concentration of 1% in pastes and mortars. The properties of thermal conductivity, density, compressive strength, and modulus of elasticity were determined. The simulation of the thermal transmittance of cladding panels applied to a facade was also performed. Mortars with a H2O2 concentration of 0.2% obtained a compressive strength of 18 MPa and thermal conductivity of 0.55 W/mK, which was 60% less than the thermal conductivity obtained for the reference composition. The simulation of a panel for use on a facade showed that the thermal resistance increased from 0.27 (m2.K/W) to 0.42 (m2.K/W), indicating the efficiency of the geopolymer for use as a thermal control material.

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Almtori, Safaa A. S., Raad Jamal Jassim, Dhia Chasib Ali, Esraa Habeeb Kadhim, and Raheem Al-Sabur. "Sustainable Manufacturing Process Applied to Produce Waste Polymer-Polymer Matrix Composites." Environmental Research, Engineering and Management 79, no. 1 (April 11, 2023): 122–32. http://dx.doi.org/10.5755/j01.erem.79.1.32907.

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Getting rid of plastic and rubber waste is one of the goals of achieving a sustainable lifestyle. Out-of-service tires and fuel and water tanks manufactured from polyvinyl chloride (PVC) are the most common waste that cities suffer from. This paper aims to investigate the effect of reinforced waste polymer particles on the polyester resin matrix when producing polymer matrix composite materials from waste tires and damaged plastic water tanks with different polymeric percentages. The polymer matrix composite could be used later in different applications, such as insulators and vibration dampers. The composite materials were evaluated by measuring the Shore D hardness, tensile strength, modulus of elasticity, and coefficient of thermal conductivity. The overall results showed hopeful behavior. Mixing a specific mixture of waste PVC and tires with polyester and hardener gives a higher tensile strength, modulus of elasticity, and Shore D hardness compared to each material when used separately. The thermal conductivity values increase with the mixing conditions between the materials. The thermal conductivity values can be reduced by using higher percentages of a mixture of waste tires and polyester or PVC and polyester. A 4.5% PVC, 4.5% tire and 91% (polyester and hardener) mixture can be recommended to improve tensile strength performance. A mix of 8.3% PVC, 8.3% tire, and 83.4% (polyester and hardener) can be recommended for high hardness.

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Shlyakhin, D. A., and M. A. Kalmova. "The nonstationary thermoelectric elasticity problem for a long piezoceramic cylinder." PNRPU Mechanics Bulletin, no. 2 (December 15, 2021): 181–90. http://dx.doi.org/10.15593/perm.mech/2021.2.16.

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А new closed-loop solution for the coupled nonstationary problem of thermoelectric elasticity is designed for a long piezoceramic radially polarized cylinder. The case of the nonstationary load acting on its inner cylindrical surface is considered as a function of temperature change at a given law of the convection heat exchange on the outer face wall (boundary conditions of heat conductivity of the 1st and 3rd types). Electrodynamic cylinder surfaces are connected to a measuring device with a high input resistance (electric idling). We investigate the problem where the rate of the temperature load changes does not affect the inertial characteristics of the elastic system. It makes it possible to expand the initial linear computational relations with the equilibrium, electrostatics and heat conductivity equations with respect to the radial component of the displacement vector, electric potential as well as the function of temperature field changes. Hyperbolic LS-theory of the thermal conductivity is used in the computations. The problem is solved with a generalized method of biorthogonal finite integral transformation based on a multicomponent ratio of eigen functions of two homogeneous boundary value problems. The structural algorithm of this approach allows identifying a conjugated operator, without which it is impossible to solve non-self-conjugated linear problems in mathematical physics. The resulted computational relations make it possible to determine the stress-strain state, temperature and electric fields induced in the piezoceramic element under an arbitrary external temperature effect. By connecting the electroelastic system to the measuring tool, we can find voltage. Firstly, the analysis of the numerical results allows identifying the rate of the temperature load changes, at which it is necessary to use the hyperbolic theory of thermal conductivity. Secondly, it allows determining the physical characteristics of the piezoceramic material for the case when the rate of changing the body volume leads to a redistribution of the temperature field. The developed computational algorithm can be used to design non-resonant piezoelectric temperature sensors.

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Ozturk, Hasan. "Prediction of Optimum Veneer Drying Parameters with Artifi cial Neural Networks for Production of Plywood with High Mechanical Properties." Drvna industrija 74, no. 3 (September 29, 2023): 297–308. http://dx.doi.org/10.5552/drvind.2023.0074.

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Veneer drying is the manufacturing process in the plywood industry that most affects energy consumption and panel properties such as bonding and bending. Therefore, the veneer drying temperature and moisture content should be accurately adjusted. Moreover, the determination of veneer thermal conductivity is as important as these two parameters and the thermal conductivity values should also be specifi ed when forming the drying programs. This study aimed to predict the optimum values of the veneer drying temperatures, moisture content and thermal conductivity, which gave the best mechanical properties, by artifi cial neural network (ANN) analysis. Poplar (Populus deltoidesI-77/51) and spruce (Picea orientalis L.) veneers and urea formaldehyde (UF) resin were used in the production of plywood. The thermal conductivity of veneer and the bonding, bending strength and elasticity modulus of the panels were tested by the relevant standards. The most accurate and reliable prediction models were obtained by analyzing the experimental data with ANN. The optimum veneer drying temperature, moisture content and thermal conductivity values that gave the best values for all three mechanical properties were 149 °C, 6.2 % and 0.02668 W/mK for poplar and 116 °C, 4.4 % and 0.02534 W/mK for spruce.

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Sulaberidze, V. Sh, and E. A. Skorniakova. "PHYSICO-MECHANICAL, THERMAL AND ELECTRICAL CHARACTERISTICS COMPOSITE MATERIALS BASED ON POLYURETHANE BINDER AND MINERAL FILLERS." Issues of radio electronics, no. 7-8 (September 5, 2020): 14–21. http://dx.doi.org/10.21778/2218-5453-2020-7-8-14-21.

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The article presents the results of studies of the physical, mechanical, thermal and electrical characteristics of composite materials based on polyurethane as a binder and mineral fillers from fine powders AlN, Al(OH)3, SiO2, CaSiO3 with a content of up to 70 wt.%. These composite materials are used to create modern sealants and dielectric coatings that meet special requirements for strength, elasticity, heat resistance, including those that do not support combustion (by using flame retardants). Dependences of tensile strength, coefficient of elasticity, modulus of elasticity under compression and hardness of samples, electrical resistivity and thermal conductivity on the mass content of the filler were determined. It was found that in terms of the combination of physical and mechanical characteristics, the compositions based on the applied polyurethane are more durable, elastic and resilient than compositions based on a silicone binder with the same fillers previously studied by the authors.

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Munawar, Muhammad A., and Dirk W. Schubert. "Thermal-Induced Percolation Phenomena and Elasticity of Highly Oriented Electrospun Conductive Nanofibrous Biocomposites for Tissue Engineering." International Journal of Molecular Sciences 23, no. 15 (July 30, 2022): 8451. http://dx.doi.org/10.3390/ijms23158451.

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Highly oriented electrospun conductive nanofibrous biocomposites (CNBs) of polylactic acid (PLA) and polyaniline (PANi) are fabricated using electrospinning. At the percolation threshold (φc), the growth of continuous paths between PANi particles leads to a steep increase in the electrical conductivity of fibers, and the McLachlan equation is fitted to identify φc. Annealing generates additional conductive channels, which lead to higher conductivity for dynamic percolation. For the first time, dynamic percolation is investigated for revealing time-temperature superposition in oriented conductive nanofibrous biocomposites. The crystallinity (χc) displays a linear dependence on annealing temperature within the confined fiber of CNBs. The increase in crystallinity due to annealing also increases the Young’s modulus E of CNBs. The present study outlines a reliable approach to determining the conductivity and elasticity of nanofibers that are highly desirable for a wide range of biological tissue applications.

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PhD, M.B. Mukhitdino, PhD, I. I. Akhmedov and I. I. Umarov. "Comprehensive Analysis of the Research Results of Wear Resistance and Physical and Mechanical Properties of Composite Polymer Materials." European Journal of Higher Education and Academic Advancement 1, no. 1 (January 13, 2024): 174–84. http://dx.doi.org/10.61796/ejheaa.v1i1.352.

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This article discusses the results of studies of the influence of filler content on the wear rate and physical and mechanical properties of composite polymer materials, in particular wear resistance, hardness, dynamic modulus of elasticity, tensile and impact strength, thermal conductivity and volumetric resistance of these materials working in contact interaction with concrete.

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Chen, Yunfei, Deyu Li, Jennifer R. Lukes, and Arun Majumdar. "Monte Carlo Simulation of Silicon Nanowire Thermal Conductivity." Journal of Heat Transfer 127, no. 10 (May 18, 2005): 1129–37. http://dx.doi.org/10.1115/1.2035114.

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Monte Carlo simulation is applied to investigate phonon transport in single crystalline Si nanowires. Phonon-phonon normal (N) and Umklapp (U) scattering processes are modeled with a genetic algorithm to satisfy energy and momentum conservation. The scattering rates of N and U scattering processes are found from first-order perturbation theory. The thermal conductivity of Si nanowires is simulated and good agreement is achieved with recent experimental data. In order to study the confinement effects on phonon transport in nanowires, two different phonon dispersions, one from experimental measurements on bulk Si and the other solved from elastic wave theory, are adopted in the simulation. The discrepancy between simulations using different phonon dispersions increases as the nanowire diameter decreases, which suggests that the confinement effect is significant when the nanowire diameter approaches tens of nanometers. It is found that the U scattering probability in Si nanowires is higher than that in bulk Si due to the decrease of the frequency gap between different modes and the reduced phonon group velocity. Simulation results suggest that the dispersion relation for nanowires obtained from elasticity theory should be used to evaluate nanowire thermal conductivity as the nanowire diameter is reduced to the sub-100 nm scale.

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Maglad, Ahmed M., Osama Zaid, Mohamed M. Arbili, Guilherme Ascensão, Adrian A. Șerbănoiu, Cătălina M. Grădinaru, Rebeca M. García, Shaker M. A. Qaidi, Fadi Althoey, and Jesús de Prado-Gil. "A Study on the Properties of Geopolymer Concrete Modified with Nano Graphene Oxide." Buildings 12, no. 8 (July 22, 2022): 1066. http://dx.doi.org/10.3390/buildings12081066.

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This paper reports the results of a study conducted to examine the impacts of adding graphene oxide (GO) to GBFS-fly ash-based geopolymer concrete. The geopolymer concrete’s compressive strength, thermal conductivity, and modulus of elasticity were assessed. X-ray diffraction (XRD) analysis was conducted to understand the differences in mineralogical composition and a rapid chloride penetration test (RCPT) to investigate the changes in the permeability of chloride ions imposed by GO addition. The results showed that adding 0.25 wt.% GO increases the modulus of elasticity and compressive strength of GBFS-FA concrete by 30.5% and 37.5%, respectively. In contrast, permeability to chloride ions was reduced by 35.3% relative to the GO-free counterparts. Thermal conductivity was decreased as GO dosage increased, with a maximum reduction of 33% being observed in FA65-G35 wt.% samples. Additionally, XRD showed the suitability of graphene oxide in geopolymer concrete. The present research demonstrates very promising features of GO-modified concrete that exhibit improved strength development and durability compared to traditional concrete, thus further advocating for the wider utilization of geopolymer concrete manufactured from industrial byproducts.

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Dong, Yuan, Chi Zhang, Min Meng, Melinda M. Groves, and Jian Lin. "Novel two-dimensional diamond like carbon nitrides with extraordinary elasticity and thermal conductivity." Carbon 138 (November 2018): 319–24. http://dx.doi.org/10.1016/j.carbon.2018.06.016.

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Mohr, Markus, Layal Daccache, Sebastian Horvat, Kai Brühne, Timo Jacob, and Hans-Jörg Fecht. "Influence of grain boundaries on elasticity and thermal conductivity of nanocrystalline diamond films." Acta Materialia 122 (January 2017): 92–98. http://dx.doi.org/10.1016/j.actamat.2016.09.042.

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Yakushin, Vladimir, Ugis Cabulis, Velta Fridrihsone, Sergey Kravchenko, and Romass Pauliks. "Properties of polyurethane foam with fourth-generation blowing agent." e-Polymers 21, no. 1 (January 1, 2021): 763–69. http://dx.doi.org/10.1515/epoly-2021-0081.

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Abstract Climate change makes it imperative to use materials with minimum global warming potential. The fourth-generation blowing agent HCFO-1233zd-E is one of them. The use of HCFO allows the production of polyurethane foam with low thermal conductivity. Thermal conductivity, like other foam properties, depends not only on the density but also on the cellular structure of the foam. The cellular structure, in turn, depends on the technological parameters of foam production. A comparison of pouring and spray foams of the same low density has shown that the cellular structure of spray foam consists of cells with much less sizes than pouring foam. Due to the small size of cells, spray foam has a lower radiative constituent in the foam conductivity and, as a result, a lower overall thermal conductivity than pouring foam. The water absorption of spray foam, due to the fine cellular structure, also is lower than that of pouring foam. Pouring foam with bigger cells has higher compressive strength and modulus of elasticity in the foam rise direction. On the contrary, spray foam with a fine cellular structure has higher strength and modulus in the perpendicular direction. The effect of foam aging on thermal conductivity was also studied.

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Xing, Yuze, Hui Jia, Zhefan Wang, Lijing Xie, Dong Liu, Zheng Wang, Meng Li, and Qingqiang Kong. "Vacuum-Filtration-Assisted Ice-Templated Freeze Drying for Preparing Capacitive Graphene Aerogel for Thermal Management." Crystals 13, no. 3 (March 7, 2023): 458. http://dx.doi.org/10.3390/cryst13030458.

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Graphene aerogel (GA) is widely used in electronic devices owing to its light weight, elasticity, and excellent thermal conductivity. GA has been prepared using various methods. However, the preparation process is complex and the thickness is hard to control, which limits its application. There is an urgent need for a new and simple method to fabricate graphene aerogel. Herein, we describe a novel strategy for fabricating GA via a vacuum filtration–ice template freeze-drying method. The stability of graphene oxide slurry (GOS) was changed by using hydrochloric acid (HCl, 0.12 mol/L), and then GA was quickly obtained by vacuum filtration–ice template freeze drying and graphitization. The obtained GA reveals a symmetrical hyperbolic structure in the vertical direction, giving it excellent thermal and electrical conductivity and good compression performance. The electrical conductivity is up to 14.87 S/cm and the thermal conductivity is 1.29 W m−1 K−1 when the density is 36 mg cm−3. The pressure only needs 0.013 MPa when the strain of GA is 50%. GA has considerable potential for the application of supercapacitors owing to the high conductivity and low density.

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Malisic, Vanja, Marina Stamenovic, and Slavisa Putic. "Thermal vision of fracture behavior on acrylic composites." Chemical Industry and Chemical Engineering Quarterly, no. 00 (2021): 4. http://dx.doi.org/10.2298/ciceq200928004m.

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The aim of this work was to investigate thermal properties of acrylate-based composite combined with alumina-based particles. The composites were made of poly (methyl methacrylate) (PMMA) modified with dimethyl itaconate (DMI) as a matrix. As reinforcement were used alumina particles (Al2O3) and alumina doped with iron oxide (Al2O3-Fe) modified with 3-aminopropyl-trimethoxylane (AM) and flax oil fatty acid methyl esters (biodiesel - BD). According to the thermal conductivity measurements, the highest thermal conductivity values had the composite with alumina particles with the highest alpha phase content. With the addition of modified alumina particles to PMMA/DMI matrix mechanical properties were improved (tensile strength, modulus of elasticity and elongation at break). Composite with 3 wt. % Al2O3-Fe-AM particles had the most improved mechanical properties. It was noticed that this composite, compared to PMMA, had the lowest temperature in a crack zone (10.28%) and that is due to the better stiffness and highest thermal conductivity. The results indicated that the Sobel fractured surface area is related to the crack energy, which is reflected by the temperature of sample monitored by thermal vision.

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Wang, Chuan Gui, Shuan Gyan Zhang, and Heng Wu. "Performance of Cement Bonded Particleboards Made from Grapevine." Advanced Materials Research 631-632 (January 2013): 765–70. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.765.

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Cement bonded particleboards were manufactured form grapevine stalk particles. The physical and mechanical properties of the boards were assessed. Results revealed that the mixture of grapevine-cement for either treatment of particles, was graded as “low inhibition” when CaCl2 was incorporated, as determined by the hydration tests. Three factors namely grapevine-cement ratio, water-cement ratio and particle size were applied in this study for the board manufacturing. Increase in grapevine-cement ratio caused decrease in Modulus of rupture (MOR), Modulus of elasticity (MOE), Internal bond (IB), thermal conductivity and increase in Thickness swelling (TS). Increase in water-cement ratio caused decrease in MOR, MOE, IB, TS and thermal conductivity. The particle size resulted in little change in all, but TS. The MOR, MOE, IB of the boards were significantly affected by grapevine-cement and water-cement ratios except for TS. Only the effect of particle size on thermal conductivity is significant at 0.05 level significance.

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Liu, Fengqi, Chenbo He, Yonggang Jiang, Junzong Feng, Liangjun Li, Guihua Tang, and Jian Feng. "Ultralight Ceramic Fiber Aerogel for High-Temperature Thermal Superinsulation." Nanomaterials 13, no. 8 (April 7, 2023): 1305. http://dx.doi.org/10.3390/nano13081305.

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Emerging fiber aerogels with excellent mechanical properties are considered as promising thermal insulation materials. However, their applications in extreme environments are hindered by unsatisfactory high-temperature thermal insulation properties resulting from severely increased radiative heat transfer. Here, numerical simulations are innovatively employed for structural design of fiber aerogels, demonstrating that adding SiC opacifiers to directionally arranged ZrO2 fiber aerogels (SZFAs) can substantially reduce high-temperature thermal conductivity. As expected, SZFAs obtained by directional freeze-drying technique demonstrate far superior high-temperature thermal insulation performance over existing ZrO2-based fiber aerogels, with a thermal conductivity of only 0.0663 W·m−1·K−1 at 1000 °C. Furthermore, SZFAs also exhibit excellent comprehensive properties, including ultralow density (6.24–37.25 mg·cm−3), superior elasticity (500 compression cycles at 60% strain) and outstanding heat resistance (up to 1200 °C). The birth of SZFAs provides theoretical guidance and simple construction methods for the fabrication of fiber aerogels with excellent high-temperature thermal insulation properties used for extreme conditions.

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Orlander, Tobias, Eirini Adamopoulou, Janus Jerver Asmussen, Adam Andrzej Marczyński, Harald Milsch, Lisa Pasquinelli, and Ida Lykke Fabricius. "Thermal conductivity of sandstones from Biot’s coefficient." GEOPHYSICS 83, no. 5 (September 1, 2018): D173—D185. http://dx.doi.org/10.1190/geo2017-0551.1.

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Thermal conductivity of rocks is typically measured on core samples and cannot be directly measured from logs. We have developed a method to estimate thermal conductivity from logging data, where the key parameter is rock elasticity. This will be relevant for the subsurface industry. Present models for thermal conductivity are typically based primarily on porosity and are limited by inherent constraints and inadequate characterization of the rock texture and can therefore be inaccurate. Provided known or estimated mineralogy, we have developed a theoretical model for prediction of thermal conductivity with application to sandstones. Input parameters are derived from standard logging campaigns through conventional log interpretation. The model is formulated from a simplified rock cube enclosed in a unit volume, where a 1D heat flow passes through constituents in three parallel heat paths: solid, fluid, and solid-fluid in series. The cross section of each path perpendicular to the heat flow represents the rock texture: (1) The cross section with heat transfer through the solid alone is limited by grain contacts, and it is equal to the area governing the material stiffness and quantified through Biot’s coefficient. (2) The cross section with heat transfer through the fluid alone is equal to the area governing fluid flow in the same direction and quantified by a factor analogous to Kozeny’s factor for permeability. (3) The residual cross section involves the residual constituents in the solid-fluid heat path. By using laboratory data for outcrop sandstones and well-log data from a Triassic sandstone formation in Denmark, we compared measured thermal conductivity with our model predictions as well as to the more conventional porosity-based geometric mean. For outcrop material, we find good agreement with model predictions from our work and with the geometric mean, whereas when using well-log data, our model predictions indicate better agreement.

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Srichan, Surat, and Werasak Raongjant. "Characteristics of particleboard manufactured from bamboo shoot sheaths." E3S Web of Conferences 187 (2020): 03011. http://dx.doi.org/10.1051/e3sconf/202018703011.

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This study emphasizes on the physical, mechanical, and thermal properties of single-layer particleboard manufactured from bamboo shoot sheaths. Particleboards were produced through the hot-pressed process and glued together by Diphenylmethane Diisocyanate (MDI) adhesive. This is in order for producing specified densities of boards as 400-kg, 600-kg, and 800-kg per m3. The raw material was sieved into four sizes: No.1-No.4 mesh. The particleboards were used to find board density, water absorption, thickness swelling, modulus of elasticity, modulus of rupture in bending, and internal bonding according to the JIS standard. Coefficients of thermal conductivity (k) of boards were discovered by a heat flow meter in steady-state conditions. The results showed that the particleboard performed outstandingly in terms of tensile strength perpendicular to the surface (internal bonding) and low thermal conductivity. However, there were some weaknesses found from their characteristics that were high water absorption and thickness of swelling, low modulus of elasticity and modulus of rupture comparing to standard criteria. The results also indicated that bamboo shoot sheaths, the agricultural residue, can be produced as particleboard, and are appropriate for an indoor heat insulator, but further investigation is required to improve the strength and durability of the particleboard.

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Li, Yitian, Anran Guo, Xiaojing Xu, Yunjia Xue, Liwen Yan, Feng Hou, and Jiachen Liu. "Preparation and Properties of Highly Elastic, Lightweight, and Thermally Insulating SiO2 Fibrous Porous Materials." Materials 15, no. 9 (April 23, 2022): 3069. http://dx.doi.org/10.3390/ma15093069.

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Fibrous porous materials are one of the most commonly used high-temperature insulation materials because of their high porosity and low thermal conductivity. Due to their wide applications in the aerospace and energy industries, the investigation of high-elastic thermally insulating porous materials has attracted increasing attention. In order to improve the elasticity of fibrous porous materials, quartz fibers with high aspect ratio were used as matrix, sodium hexametaphosphate (SHMP) was selected as dispersant. We innovatively reported that a unique three-dimensional skeleton structure was constructed by adjusting the dispersion of fibers in the slurry, and the lightweight, thermal insulating and elastic SiO2 fibrous porous material was then prepared by the compression molding method. The characterization results of zeta potential and absorbance showed that the addition of SHMP was an effective method to enhance the dispersibility of quartz fibers in the slurry. SiO2 fibrous porous materials with 0.4 wt% SHMP content exhibited an ideal three-dimensional skeleton structure, which endowed the porous material with high porosity (89.39%), low density (0.04751 g/cm3), and low thermal conductivity (0.0356 W·m−1·K−1). The three-dimensional skeleton structure formed by overlapping fibers with high aspect ratios endowed the porous material with excellent elasticity. SiO2 fibrous porous materials with 0.4 wt% SHMP content could undergo large strains of 30% and achieved a resilience ratio of 81.69% under the 30th compression cycle. Moreover, after heat treatment at 800 °C, SiO2 fibrous porous materials also maintained good elasticity with a resilience ratio of more than 80%.

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