scholarly journals Investigation of the Thermo-Physical and Mechanical Properties of Coir and Sugarcane Bagasse for Low Temperature Insulation

2021 ◽  
Vol 6 (4) ◽  
pp. 340-356
Author(s):  
Mustapha Ndagi ◽  
Ajiboye Tajudeen Kolawole ◽  
Fabiyi Mustapha Olawale ◽  
Abdulkareem Sulaiman
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Low Temperature ◽  
Sugarcane Bagasse ◽  
Control Sample ◽  
Gum Arabic ◽  
Absorption Capacity ◽  
Thermal Resistivity ◽  
Insulating Materials ◽  
Insulating Material

This research  reports on the suitability of Agricultural bi-products as low temperature thermal insulating materials to replace synthetic insulating materials like polyurethane used in food warmers and ice coolers. Coir and sugarcane bagasse chosen for this research was based on literature review and local availability of materials. Coir was obtained from Badagry, Lagos State and Sugarcane bagasse obtained from Batati, Niger State, the materials were washed, sun dried for three days and cut into smaller pieces before being blended into smaller particles using an electric blender. The blended materials (Coir and Bagasse) were sieved into two different sieve size of 0.5 mm and 1.0 mm respectively.  The particles sizes were then combined into blend ratios of 50/50, 60/40, and 70/30 using Gum Arabic as binder. Thermal conductivity test showed that 1.0 mm particle size coir mixed with sugarcane bagasse has the lowest thermal conductivity of 0.01467 W/mK whilst that of 0.5 mm particle size has thermal conductivity of 0.01472 W/mK this is lower compared to the measured thermal conductivity of the polyurethane control sample of 0.01832 W/mK. Sample F (1.0 mm particle size,70% coir and 30% bagasse) with a thermal diffusivity of 5.15  m²/s, water absorption capacity of 410 %, UTS of 0.219 MPa, Compressive strength of 0.583 MPa, Specific heat capacity of 1141.3 J/kgK and thermal resistivity of 68.16 W/m/K is most suitable replacement for polyurethane as low temperature thermal insulator. This is corroborated by the performance evaluation test with carried out between polyurethane lined food warmer and bio-composite lined food warmer. The two test samples have close ice melt rate values and the polyurethane slightly edge the Bio-composite insulating material by 1.2 % in efficiency. The edge in efficiency can be accepted as all materials used in the development of the bio-composite insulating material are completely bio-degradable and environmentally friendly.

scholarly journals Determination of thermal properties of some ceiling material commonly used in Ijebu- Ode, Nigeria

2020 ◽  
Vol 9 (1) ◽  
pp. 23-27
Author(s):  
J.O. Adepitan ◽  
F.O. Ogunsanwo ◽  
J.D. Ayanda ◽  
A.A. Okusanya ◽  
A.D. Adelaja ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Tropical Rainforest ◽  
Building Construction ◽  
Thermal Resistivity ◽  
Electrical Method ◽  
Insulating Materials ◽  
Insulating Material ◽  
Range Of Values

The study investigates the thermal properties of different insulating material used in building construction in Ijebu Ode, a tropical rainforest region, south western, Nigeria. Five insulating material; asbestos, Plaster of Paris (P.O.P), PolyVinyl Chloride (PVC), hardboard and paperboard, were subjected to thermal investigation using Lee’s disc electrical method. The result obtained showed that the thermal conductivities obtained are within the range of values specified for good insulating materials. Asbestos was found to be associated with the least thermal conductivity of the value 𝟎. 𝟏𝟕𝟏𝟕 𝑾𝒎-𝟏𝑲-𝟏while PVC had the highest thermal conductivity values of 𝟏. 𝟔𝟒𝟗𝟗 𝑾𝒎-𝟏𝑲-𝟏. This may be associated with the temperature and the heat flux on the surface of the material. The results obtained for thermal conductivity, thermal resistivity and thermal diffusivity correlated favourably when compared with those of previous work from other locations. Asbestos being the material with the lowest thermal conductivity is therefore recommended for use as the suitable insulating ceiling material in the study area. Keywords: thermal conductivity, diffusivity, resistivity, Lee’s disc

Cross-linked poly(hydroxy imide) gate-insulating materials for low-temperature processing of organic thin-film transistors

2018 ◽  
Vol 6 (48) ◽  
pp. 13359-13366 ◽  
Author(s):  
Joo-Young Kim ◽  
Ji Whan Kim ◽  
Eun Kyung Lee ◽  
Jeong-Il Park ◽  
Bang-Lin Lee ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Breakdown Voltage ◽  
Thin Film Transistors ◽  
Organic Thin Film Transistors ◽  
Organic Thin Film ◽  
Insulating Materials ◽  
Plastic Substrates ◽  
Insulating Material ◽  
Low Temperature Processing

This paper reports a polymeric gate insulating material of poly(hydroxy imide) cured at the low temperature of 130 °C for the application to organic thin-film transistors on plastic substrates exhibiting high breakdown voltage and no hysteresis.

Study of the Impact of Rice Straw Particle Size on the Mechanical and Thermal Properties of Straw Lime Concretes

2022 ◽  
Author(s):  
Youssef El Moussi ◽  
Laurent Clerc ◽  
Jean-Charles Benezet
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Water Absorption ◽  
Rice Straw ◽  
Absorption Capacity ◽  
Mechanical And Thermal Properties ◽  
Water Absorption Capacity ◽  
The Impact

The use of bio-based concretes performed with lignocellulosic aggregates constitute an interesting solution for reducing the energy consumption, greenhouse gas emissions and CO2 generated by the building sector. Indeed, bio-based materials could be used as an alternative of traditional materials such as expended polystyrene and mineral resources (e.g. glass and rock wools) for insulation. Furthermore, these bio-based concretes are known for their interesting insulation properties, indeed they allow to enhance thermal properties of buildings and enables moisture management which lead to design efficient building materials. For this purpose, bio-based concrete using rice straw as aggregate are studied in this present work. The impact of the characteristics of rice straw particle (particle size distribution, bulk density, and water absorption capacity, etc.) on both the mechanical and thermal properties of the bio-based concrete are investigated. Five formulations of rice straw concrete are examined, compared and then classified in terms of insulation properties and mechanical properties. The assessments are based on the measurement of density and thermal conductivity. The variation of compressive strength in function of the characteristics (mean particle length) of rice straw particle are assessed and discussed. The investigation covers also the porosity and density. Tests are also carried out on agricultural by-products with a view to highlight their chemical, physical and structural proprieties. The results show that the use of large particles with low water absorption capacity induce lighter concretes with the density between 339 and 505 kg/m3 and lead to a high compressive strength with a high mechanical deformability. Furthermore, it appears that an increase in the average length of rice straw particle lead to decrease of thermal conductivity of bio-based concretes. It varies from 0.062 to 0.085 W/(m.K).

scholarly journals Thermophysical Properties of Larch Bark Composite Panels

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2287
Author(s):  
Lubos Kristak ◽  
Ivan Ruziak ◽  
Eugenia Mariana Tudor ◽  
Marius Cătălin Barbu ◽  
Günther Kain ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Urea Formaldehyde ◽  
Raw Material ◽  
Particle Orientation ◽  
Thermal Resistivity

The effects of using 100% larch bark (Larix decidua Mill) as a raw material for composite boards on the thermophysical properties of this innovative material were investigated in this study. Panels made of larch bark with 4–11 mm and 10–30 mm particle size, with ground bark oriented parallel and perpendicular to the panel’s plane at densities varying from 350 to 700 kg/m3 and bonded with urea-formaldehyde adhesive were analyzed for thermal conductivity, thermal resistivity and specific heat capacity. It was determined that there was a highly significant influence of bulk density on the thermal conductivity of all the panels. With an increase in the particle size, both parallel and perpendicular to the panel´s plane direction, the thermal conductivity also increased. The decrease of thermal diffusivity was a consequence of the increasing particle size, mostly in the parallel orientation of the bark particles due to the different pore structures. The specific heat capacity is not statistically significantly dependent on the density, particle size, glue amount and particle orientation.

Heat-Insulating Materials Obtaining from Dispersive Screenings of Construction Sand

2014 ◽  
Vol 1040 ◽  
pp. 314-318
Author(s):  
Olga Kazmina ◽  
Maria Dushkina ◽  
Svetlana Volland ◽  
Elena Lebedeva
Keyword(s):  
Particle Size ◽  
Low Temperature ◽  
Water Absorption ◽  
Insulating Materials ◽  
Crystal Material ◽  
Value Of Water

It is established that the eliminations of construction sand with the content of SiO2 about 70 wt. % and particle size less than 60 mk are suitable for the production of a foamglass-crystal material on the basis of the low-temperature frit, which was synthesized at the temperature 900 °C. The obtained foamglass-crystal material exceeds foamglass (by 3.0 times) and clayite (by 1.5 times) by strength and is characterized by low value of water absorption (0.1 %).

Fabrication of Cofired ALN Multilayer Substrates at Low Temperature Sintering

1993 ◽  
Vol 323 ◽  
Author(s):  
Koichi Terao ◽  
Ichiro Uchiyama ◽  
Akihiro Hamano
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Low Temperature ◽  
Oxygen Content ◽  
Substrate Material ◽  
Low Temperature Sintering ◽  
Dense Microstructure ◽  
High Adhesion ◽  
Porous Microstructure ◽  
Powder Properties

AbstractIn order to lower the firing temperature of W cofired AlN multilayer substrates, sinterabilities of AlN substrate material and W conductor were investigated at low sintering temperatures around 1650 •C.In case of AIN substrate material, the effect of AIN powder properties on sinterability and thermal conductivity was evaluated. The powders, with specific surface area between 2.3 and 8.2m2• g−1 and oxygen content between 0.7 and 3.2 wt%, were sintered with CaO and Y2O3 as sintering additives. The finer powder promoted the densification below 1600°C and each powder was fully densified at 1650°C. However thermal conductivity sintered at 1650°C decreased with decreasing particle size due to increasing oxygen content inside AlN grains. The thermal conductivity of optimized AlN substrate sintered at 1650°C had over 100W • m−1 K−1.W conductor is required dense microstructure for high adhesion strength to AlN substrate. Shrinkage mismatch between AlN and W during sintering caused porous microstructure for coarse W powders or detaching for fine W powders. The optimized W paste was developed for low temperature sintering.

scholarly journals Influence of Surface Emissivity and of Low Emissivity Shields on the Thermal Properties of Low Density Insulating Materials

2011 ◽  
Author(s):  
Mariacarla Arduini ◽  
Manuela Campanale ◽  
Lorenzo Moro
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Test Temperature ◽  
Transfer Factor ◽  
Thermal Characteristics ◽  
Expanded Polystyrene ◽  
Low Density ◽  
Insulating Materials ◽  
Insulating Material ◽  
Radiation Extinction

The theory of heat transfer through low density insulating materials explains the importance of thermal radiation in the overall heat transfer. As a matter of fact, in many semitransparent insulating materials, radiation has a considerable influence on measured thermal conductivity. In this work we continue the investigation (both experimentally and theoretically) on the heat transfer through low density insulating materials that we started some years ago and whose results have been presented in some International Conferences. Test have been done on low density insulating materials: expanded polystyrene with a density of 10 kg/m3 and polyester fibres with a density of 9 kg/m3 (these last tests are not yet completed and will not be discussed in this paper). The transfer factor T was measured in the heat flow meter apparatus of our laboratory [1]. The first measurements have been done with the two surfaces of the apparatus uncoated (emissivity ε = 0.91) at a mean test temperature of 283 K (10 °C) and then with the specimens enclosed in the aluminium foils (emissivity ε = 0.045) at the same mean test temperature. The results obtained from the measurements of the transfer factor T pointed out that a change of the emissivity ε of the surfaces from 0.91 to 0.045 caused a considerable decreasing of the transfer factor. Then the same panels have been cut into two slices and the aluminium foil has been interposed also between the slices, as shield, and the transfer factor was measured again in both cases: at first with the surfaces of the apparatus uncoated and then with the surfaces of the apparatus coated with the aluminium foils. In both cases the decreasing of the transfer factor τ was not negligible. The radiation extinction parameters have been then measured with a spectrometer and a model has been found to predict the transfer factor T in function of the testing conditions. We can conclude that in presence of a thin reflective metal cover placed on a low density insulating material, the thermal conductivity decrease immediately (about 7%) with a significant improvement of the thermal characteristics of the insulating material. If we put then some low emissivity foils between the slices of the material, another considerable decreasing of the thermal conductivity can be obtained (about 10%) and in presence of both aluminum foils (inside and outside). This fact confirms the importance of the contribution of radiation in thermal transmissivity of low density insulating materials and gives the possibility to reduce and to predict the thermal performances of such a material.

Research on Thermal-Insulating Material and Roadway Cooling with High Geotherm

2012 ◽  
Vol 512-515 ◽  
pp. 915-921
Author(s):  
Yan Wei Liu ◽  
Guo Fu Li ◽  
Xiao Yong Liu
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
High Performance ◽  
Experimental Models ◽  
Industrial Test ◽  
Mine Pressure ◽  
Test Model ◽  
Insulating Materials ◽  
Insulating Material ◽  
Thermal Insulating

The research aims to develop inorganic thermal-insulating materials of high performance, decrease high geothermal emissions from hot rock to the roadway, reduce the roadway airflow temperature, and achieve mine cooling and energy saving eventually. Firstly, the best proportion of inorganic thermal-insulating materials of high performance was designed, and a test model for thermal conductivity and mechanical analysis has been built. And through the test of thermal-insulating of the material and mechanical properties, the relation equations between vitreous micro-bead content (the main agent of thermal-insulating material) and thermal conductivity, uniaxial compressive strength, confined compressive strength have been obtained respectively. Secondly, the feature, the fitting and coupling features between the experimental models and engineering conditions in practice were analyzed comparatively, which could provide theoretical basis for the design and application of thermal-insulating materials of high performance. The industrial test shows that with thermal-insulating materials of high performance in application, the roadway airflow temperature was reduced significantly and could meet the requirements of mine pressure. Therefore, the research could offer an effective way for the mine thermal-insulating and cooling under high geothermal conditions.

scholarly journals Using of Aerogel to Improve Thermal Insulating Properties of Windows

2018 ◽  
Vol 14 (1) ◽  
pp. 2-11 ◽  
Author(s):  
Denisa Valachova ◽  
Nada Zdrazilova ◽  
Vladan Panovec ◽  
Iveta Skotnicova
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Building Structures ◽  
Insulating Materials ◽  
Insulating Material ◽  
Composite Systems ◽  
Thermal Insulating ◽  
Technical Requirements ◽  
Technical Properties ◽  
Insulating Properties

AbstractFor the best possible thermal-technical properties of building structures it is necessary to use materials with very low thermal conductivity. Due to the increasing thermal-technical requirements for building structures, the insulating materials are developed. One of the modern thermal insulating materials is so-called aerogel. Unfortunately, this material is not used in the field of external thermal insulation composite systems because of its price and its properties. The aim of this paper is to present possibilities of using this insulating material in the civil engineering - specifically a usage of aerogel in the production of windows.

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