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We show that this is the principal factor for the very low thermal conductivity.
This model of diffuson-mediated thermal conductivity may thus help explain experimental results of ultralow thermal conductivity.
The results proved that the thermal conductivity can be improved substantially by...
The thermal conductivity of insulating polymers can be increased by adding conductive fillers.
Test results indicate that the thermal conductivity increases with increasing temperature.
The addition of conductive filler in a polymer matrix is an effective way to increase the thermal conductivity of the plastic materials, as required by several industrial applications.
The measurements show that both purity and thermal treatment strongly influence the value of thermal conductivity.
The predictions of an effective thermal conductivity agree with the experimental data.
Adding thermally conductive fillers to polymers the thermal conductivity can be raised significantly.

Related Questions

Does plastic have a higher thermal conductivity than wood?4 answersPlastic generally has a higher thermal conductivity than wood. Wood-plastic composites (WPCs) exhibit varying thermal conductivities based on their composition. Studies show that increasing the wood content in WPCs leads to a reduction in thermal conductivity, with values decreasing by 6-8.5% for each 10% increase in wood concentration. Additionally, the incorporation of high-density polyethylene and polypropylene in WPCs affects their thermal properties, with thermal conductivity increasing as temperatures rise and with added water content. Comparatively, plastics with modified graphite and other additives can achieve higher thermal conductivities than wood, especially when utilizing inorganic fillers with significantly higher thermal conductivities than the base resin. Therefore, in general, plastics can exhibit higher thermal conductivity than wood, especially in composite materials.
Relaxation time approximation for the calculation of thermal conductivity is valid for materials with low thermal conductivity?4 answersThe relaxation time approximation for the calculation of thermal conductivity is valid for materials with low thermal conductivity. However, it is important to note that this approximation assumes an isotropic medium and can lead to errors in predictions at low temperatures and when anharmonic effects become significant. In analytical calculations, these errors are often offset by the use of fitting parameters. Therefore, while the relaxation time approximation can be used for materials with low thermal conductivity, it is necessary to consider its limitations and potential inaccuracies in certain temperature ranges and when anharmonic effects are significant.
What is the thermal conductivity of an insulation material?5 answersThe thermal conductivity of an insulation material refers to its ability to conduct heat. It is an important parameter in determining the energy efficiency of buildings and other industries that use insulation materials. The thermal conductivity of insulation materials can be influenced by factors such as temperature, moisture content, density, and the type of material used. Studies have shown that the thermal conductivity of insulation materials can increase with increasing temperature and humidity, but the degree of change varies depending on the specific material. Moisture transfer in the building envelope can also have a significant impact on the heat transfer process. Experimental methods, such as the guarded hot plate method, are commonly used to measure the thermal conductivity of insulation materials.
What are the economic impacts of reduced thermal conductivity in buildings?4 answersReducing thermal conductivity in buildings can have significant economic impacts. By using ash microspheres in the production of silicate materials, the thermal conductivity of the manufactured material can be significantly reduced, leading to lower heat losses through the enclosing walls of buildings and structures. Additionally, using a low loose weight density expanded perlite can lower the thermal conductivity of insulating compositions. The use of nanoparticle packed bed (NPB) as a thermal insulation material can also result in ultra-low thermal conductivities, further reducing heat transfer in buildings. These improvements in thermal conductivity can lead to reduced energy consumption for heating and cooling, resulting in lower energy bills for building owners and occupants. Furthermore, the use of materials with lower thermal conductivity can contribute to improved energy efficiency and sustainability in the built environment, reducing the environmental impact of buildings.
What is the thermal conductivity of PVC pipe?8 answers
What would be the benefit of building a house with walls that have low thermal conductivity?9 answers

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What is dicalcium phosphate dihydrate in context of osteoinduction and osteoconduction?
5 answers
Dicalcium phosphate dihydrate (DCPD) is a crystalline calcium phosphate phase with significant implications in osteoinduction and osteoconduction. Studies have shown that DCPD can be utilized in bone tissue engineering to create strong composites suitable for such applications. Additionally, DCPD has been found to have high healing potential due to its biocompatibility, biodegradability, and biomechanical properties, making it a promising material for bone defect treatment. Furthermore, DCPD-rich calcium phosphate cement has been shown to enhance bioresorption and new bone formation rates, indicating its potential for improving bone reconstruction therapies. Overall, DCPD emerges as a valuable component in biomaterial development for promoting bone healing and regeneration, showcasing its importance in the field of orthopedics and bone tissue engineering.
Does dicalcium phosphate dihydrate's crystalline structure support osteoconduction?
5 answers
Dicalcium phosphate dihydrate (DCPD) has been extensively studied for its potential in bone healing. While DCPD itself may not directly support osteoconduction, its related forms like dicalcium phosphate anhydrous (DCPA) have shown promising results in promoting bone formation and union. Studies have highlighted the biocompatibility, biodegradability, and osteoinductive properties of DCPA, making it a valuable component in bone graft materials. Additionally, the crystalline nature of DCPA has been linked to enhanced bone formation and biomechanical properties, indicating its positive impact on bone healing. On the other hand, the presence of DCP in calcium phosphate cement has shown improved bioresorption and new bone formation rates, suggesting its potential therapeutic applications in bone reconstruction.
What is the value of thermal conductivity for Al2O3 nanoparicle in liquid phase?
4 answers
The thermal conductivity of Al2O3 nanoparticles in liquid phase varies based on different factors such as concentration, temperature, and particle size. Research indicates that the thermal conductivity of Al2O3 nanofluid can be significantly enhanced by dispersing the nanoparticles in a base fluid. For instance, studies have shown enhancements ranging from 1.8% to 21.44% with volume fractions between 0.01% to 0.5%. Additionally, the thermal conductivity of Al2O3 nanofluid was found to increase by 8.7% at a concentration of 0.1 wt % at 80°C. Furthermore, the thermal conductivity of Al2O3 nanofluid was observed to increase by 5% at different temperature ranges, with a notable boost beyond 55°C.
Does dicalcium phosphate dihydrate's crystalline structure support osteoconduction by promoting the adhesion and proliferation of bone cells?
5 answers
Dicalcium phosphate dihydrate (DCPD) has been recognized for its potential in promoting osteoconduction by supporting the adhesion and proliferation of bone cells. Studies have shown that DCPD, a crystalline calcium orthophosphate phase, exhibits higher metastability compared to other phases. Furthermore, the morphology of calcium orthophosphate crystals, such as octacalcium phosphate (OCP), has been found to influence the attachment, spreading, and growth of bone cells. Additionally, surface modifications involving calcium phosphate coatings have been shown to enhance cell adhesion, proliferation, and osteogenic functionality on various substrates, indicating the positive impact of calcium phosphate structures on bone cell behavior. Therefore, the crystalline structure of DCPD and related calcium phosphate coatings indeed support osteoconduction by facilitating bone cell adhesion and proliferation.
Why if roasting temperature increase, the tapped density of coffee powder also increases?
4 answers
The increase in roasting temperature leads to a rise in the tapped density of coffee powder due to various physical changes during the roasting process. As the roasting temperature increases, the total weight loss of coffee beans also increases, resulting in a decrease in bulk density of the beans. Additionally, the roasting temperature affects the bulk and bean densities of coffee, leading to changes in grain volume increase. These alterations in density parameters are influenced by the roasting temperature, impacting the overall tapped density of the coffee powder. Therefore, the relationship between roasting temperature and tapped density is intricately linked to the physical transformations that occur in the coffee beans during the roasting process, ultimately affecting the density of the resulting powder.
How does the use of agricultural waste affect the mechanical properties of composite materials?
4 answers
The utilization of agricultural waste in composite materials significantly impacts their mechanical properties. Studies have shown that incorporating agricultural residues like rice husk, banana rachis, African palm kernel shells, Sesamum indicum L., and bean pod powder into composites enhances their mechanical strength. These reinforcements lead to improvements in tensile, flexural, and compressive strength of the composites, attributed to factors such as enhanced fiber-matrix adhesion, cross-linking effects, and modifications in composite structures. Additionally, the use of agricultural waste as fillers in composites has been found to positively influence properties like thermal stability and density, offering a sustainable approach to developing materials with tailored properties for various applications.
Trans content is simbol of cristalinity in polymers ?
4 answers
The trans content in polymers is indeed a symbol of crystallinity. The higher the trans content, the greater the crystallinity observed in the polymer. For instance, in polyethylene terephthalate (PET), the transformation from gauche to trans conformation during stretching increases the trans content, which correlates well with the crystallinity observed through techniques like DSC measurement. Additionally, in polybutadienes, isomerizations to increase trans content led to more crystalline or semicrystalline structures, with a decrease in crystallinity as trans content reduced. This relationship between trans content and crystallinity is crucial in understanding the structural effects on physical properties and the overall crystallization kinetics of polymers.
What is the role of thermal diffusivity in heat transfer within materials and systems?
4 answers
Thermal diffusivity plays a crucial role in heat transfer within materials and systems by determining the speed at which heat flows through a material. It influences the intensity of heat transfer, the quality of thermal insulation, and the efficiency of power equipment. Neglecting thermal diffusivity in calculations can lead to unreliable results, emphasizing its importance in dynamic heat-related scenarios. Various methods exist to measure thermal diffusivity, such as the laser flash technique, which allows for accurate determination in different material types, including composites and porous materials. Understanding thermal diffusivity aids in modeling transient thermal processes, especially in porous materials, where effective diffusivity may exhibit time dependence. Additionally, thermal diffusivity can provide insights into subsurface heat transfer mechanisms, such as convective heat transfer and water movement in fault zones.
Risk Battery Thermal Runaway?
5 answers
The risk of thermal runaway in lithium-ion batteries is a critical safety concern that has garnered significant attention from various sectors due to its potential for causing fires and explosions. Thermal runaway occurs when the battery's internal temperature and pressure rise uncontrollably, leading to a self-sustaining chain reaction. This phenomenon can be triggered by several factors, including thermal abuse, electrical faults, and mechanical damage. Research has shown that the thermal management of batteries using composite phase change materials (CPCMs) can effectively reduce the risk of thermal runaway by absorbing excess heat and maintaining the battery's temperature within safe limits. Additionally, the development of predictive models integrating fault tree analysis, dynamic Bayesian networks, and support vector regression offers a promising approach for early warning and dynamic risk prediction of thermal runaway events. The onset temperature for thermal runaway and the severity of the reaction can vary depending on the battery's state of charge (SoC), with higher SoCs leading to more severe reactions. Moreover, the design of the battery, including the venting mechanisms and the chemistry of the cathode material, plays a significant role in the battery's behavior under abuse conditions and its ability to mitigate the consequences of thermal runaway. Experimental studies have also highlighted the importance of understanding the effects of radiative heat transfer on thermal runaway propagation within a battery pack, suggesting that radiation can either facilitate or mitigate the spread of thermal runaway depending on various factors. Furthermore, the ambient conditions, such as pressure and temperature, significantly influence the thermal runaway characteristics and the associated fire behaviors. In summary, managing the risk of thermal runaway in lithium-ion batteries requires a multifaceted approach that includes advanced thermal management strategies, predictive modeling for early detection, and careful consideration of battery design and operating conditions.
What is the thermal conductivity for Al2O3 nanoparicle in solid and liquid phase?
5 answers
The thermal conductivity of Al2O3 nanoparticles in solid and liquid phases varies based on different experimental conditions. Research indicates that the thermal conductivity of Al2O3 nanofluids dispersed in water can range from 0.531 W mK−1 to 0.736 W mK−1. Additionally, the thermal conductivity of Al2O3 nanoparticles blended with paraffin can be enhanced significantly by adding different volume concentrations of nanoparticles, with improvements observed in both solid and liquid states. Furthermore, the thermal conductivity of Al2O3 nanofluids, along with ceria and their hybrid, was experimentally measured, showing enhancements of 5.3%, 3.3%, and 8.8% at specific volume concentrations and temperatures. These findings highlight the potential for utilizing Al2O3 nanoparticles to improve thermal conductivity in both solid and liquid phases for various applications.
What temperatures Molding glass can go?
5 answers
Molding glass can be processed at temperatures ranging from 400 to 700 °C, above the glass forming temperature, with high press forces of 1-20kN imposed simultaneously. The crystallization temperature for CaO-SiO2 based flux ranges from 813 to 874 °C, while for CaO-Al2O3 based flux, it ranges from 932 to 972 °C. Precision glass molding involves heating the glass above the transition temperature Tg, pressing it into shape, and then cooling it down to approximately 200 °C, leading to uneven cooling speeds and stress distribution on the glass lens. The preferred mold temperature range for molding glass containers like bottles and jars is 480–550°C, impacting the strength of the final products. Smart-phone curved glass forming conditions were tested at temperatures of 620°C and 650°C using a glass molding system.