scholarly journals Study of the Thermal Properties of Raffia Bamboo Vinifera L. Arecaceae

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
E. Foadieng ◽  
P. K. Talla ◽  
G. B. Nkamgang ◽  
M. Fogue
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thin Shell ◽  
Low Cost ◽  
Thermal Effusivity ◽  
Palm Tree ◽  
Thermal Insulator ◽  
The Family ◽  
Analysis Of Results

Raffia is a kind of fast-growing palm tree, from the family of Arecaceae, encountered in marshy areas and along rivers. In this study, the “Raffia Bamboo” is the stalk of a palm, made of a fragile marrow inside a thin shell, smooth and hard to protect the latter. In our region, this material is widely used to build all the low-cost traditional houses and furniture, to make granaries storage of dry products, to build chicken coops, to make decoration. Thus, various jobs are organized around this material, with the fight against poverty. To our knowledge, information on its thermal properties is almost nonexistent. The experimental determination of the transverse thermal properties of the dry shell, the dry marrow, and the whole dry bamboo helped to find, for each, a specific heat, a thermal diffusivity, a thermal conductivity, and finally a thermal effusivity. From the analysis of results, we deduce that the thermal properties of raffia bamboo vinifera L. Arecacea make it a very good thermal insulator.

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

Thermal Properties of Thin Metallic Layer Deposited on Insulators: Effect of the Interface on the Independent Determination of the Thermal Diffusivity and Conductivity of the Layer

2008 ◽  
Author(s):  
Danie`le Fournier ◽  
Jean Paul Roger ◽  
Christian Fretigny
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Thermal Resistance ◽  
Thermal Contact ◽  
Heat Diffusion ◽  
Metallic Layer ◽  
Good Thermal Contact ◽  
Lateral Heat

Lateral heat diffusion thermoreflectance is a very powerful tool for determining directly the thermal diffusivity of layered structures. To do that, experimental data are fitted with the help of a heat diffusion model in which the ratio between the thermal conductivity k and the thermal diffusivity D of each layer is fixed, and the thermal properties of the substrate are known. We have shown in a previous work that it is possible to determine independently the thermal diffusivity and the thermal conductivity of a metallic layer deposited on an insulator, by taking into consideration all the data obtained at different modulation frequencies. Moreover, it is well known that to prevent a lack of adhesion of a gold film deposited on substrates like silica, an intermediate very thin (Cr or Ti) layer is deposited to assure a good thermal contact. We extend our previous work: the asymptotic behaviour determination of the surface temperature wave at large distances from the modulated point heat source for one layer deposited on the substrate to the two layers model. In this case (very thin adhesion coating whose thermal properties and thickness are known), it can be establish that the thermal diffusivity and the thermal conductivity of the top layer can still be determined independently. It is interesting to underline that the calculus can also be extended to the case of a thermal contact resistance which has often to be taken into account between two solids. We call thermal resistance a very thin layer exhibiting a very low thermal conductivity. In this case, the three parameters we have to determine are the thermal conductivity and the thermal diffusivity of the layer and the thermal resistance. We will show that, in this case, the thermal conductivity of the layer is always obtained independently of a bound of the couple thermal resistance – thermal diffusivity, the thermal diffusivity being under bounded and the thermal resistance lower bounded. Experimental results on thin gold layers deposited on silica with and without adhesion layers are presented to illustrate the method. Discussions on the accuracy will also be presented.

The Estimation of the Thermal Properties of Refractory Materials According to the Temperatures Acceleration Curve at the Blast Furnace Blowing-In

2015 ◽  
Vol 1095 ◽  
pp. 476-482 ◽  
Author(s):  
A.N. Dmitriev ◽  
Maxim O. Zolotykh ◽  
Yury A. Chesnokov ◽  
Oleg Yu. Ivanov ◽  
Galina Yu. Vitkina
Keyword(s):  
Thermal Conductivity ◽  
Mathematical Model ◽  
Blast Furnace ◽  
Thermal Properties ◽  
Thermal Conductivity Coefficient ◽  
Refractory Materials ◽  
Different Types ◽  
Definition Of ◽  
The Mathematical Model

In a laying of a hearth it is usually used to ten different types of the flameproof materials. The characteristics of materials declared by the manufacturer can differ from the actual. For creation of the mathematical model [1, 2] temperatures distributions in a laying of the concrete furnace it is necessary to know thermal conductivity of materials of the specific parties used at construction of the furnace. Definition of the thermal conductivity coefficient allows adapt mathematical model for specific conditions of use. The technique of determination of thermal properties of refractory materials on the temperatures acceleration curve at blowing-in of the blast furnace is described.

The Simultaneous Measurement of Thermal Conductivity, Thermal Diffusivity, and Perfusion in Small Volumes of Tissue

1984 ◽  
Vol 106 (3) ◽  
pp. 192-197 ◽  
Author(s):  
J. W. Valvano ◽  
J. T. Allen ◽  
H. F. Bowman
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Tissue Perfusion ◽  
Effective Thermal Diffusivity ◽  
Liver Preparation ◽  
Improved Technique ◽  
Power Response

An improved technique is presented for the “in-vivo” determination of thermal conductivity, thermal diffusivity, and perfusion using a self-heated spherical thermistor probe. In the presence of flow, solution of the time-dependent, probe-tissue coupled thermal model allows the measurement of “effective” thermal conductivity and “effective” thermal diffusivity, which represent the thermal properties of the perfused tissue. Perfusion can be quantified from both “effective” thermal properties. In the presence of flow, it has been shown that the transient power response does not follow t−1/2 as has been previously assumed. An isolated rat liver preparation has been developed to validate the measurement technique. Radioactive microspheres are used to determine the true perfusion from the total collected hepatic vein flow. Experimental data demonstrates the ability to quantify perfusion in small volumes of tissue.

scholarly journals Characterization of Nano-Mechanical, Surface and Thermal Properties of Hemp Fiber-Reinforced Polycaprolactone (HF/PCL) Biocomposites

2020 ◽  
Vol 10 (7) ◽  
pp. 2636
Author(s):  
Hom Nath Dhakal ◽  
Sikiru Oluwarotimi Ismail ◽  
Johnny Beaugrand ◽  
Zhongyi Zhang ◽  
Jurgita Zekonyte
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Natural Fiber ◽  
Low Cost ◽  
Contact Angles ◽  
Degree Of Crystallinity ◽  
Fiber Reinforced ◽  
Scanning Calorimetry ◽  
Hemp Fiber ◽  
Aspect Ratios

The quest for sustainable, low-cost and environmental friendly engineering materials has increased the application of natural fiber-reinforced polymer (FRP) composite. This paper experimentally investigates the effects of variable mean hemp fiber (HF) aspect ratios (ARs) of 00 (neat), aspect ratios AR_19, AR_26, AR_30 and AR_38 on nano-mechanical (hardness, modulus, elasticity and plasticity), surface and thermal properties of hemp fiber/polycaprolactone (HF/PCL) biocomposites. These biocomposites were characterized by nanoindentation, contact angle, surface energy, thermogravimetric analysis (TGA), thermal conductivity and differential scanning calorimetry (DSC) techniques. After nanoindentation and thermal conductivity tests, the results obtained evidently show that the HF/PCL sample with aspect ratio (AR_26) recorded optimal values. These values include maximum hardness of approximately 0.107 GPa, elastic modulus of 1.094 GPa, and plastic and elastic works of 1.580 and 1.210 nJ, respectively as well as maximum thermal conductivity of 0.2957 W/mK, when compared with other samples. Similarly, the optimal sample exhibits highest main degradable temperature and degree of crystallinity of 432 ℃ and 60.6%, respectively. Further results obtained for the total surface energies and contact angles of these samples with glycerol and distilled water are significant for their materials selection, design, manufacturing and various applications.

scholarly journals DETERMINATION OF THERMAL CONDUCTIVITY FOR ADOBE (CLAY SOIL) MIXED WITH DIFFERENT PROPORTIONS OF QUARTZ (SHARP SAND)

2019 ◽  
Vol 7 (3) ◽  
pp. 335-345
Author(s):  
S. K Singh ◽  
Ngaram S. M. ◽  
Wante H. P.
Keyword(s):  
Thermal Conductivity ◽  
Correlation Coefficient ◽  
Building Materials ◽  
Clay Soil ◽  
Building Construction ◽  
Average Correlation ◽  
Thermal Insulator ◽  
Materials Used ◽  
Thermal Conductivities

This research investigated the thermal conductivity of Adobe mixed with Quartz in view of their availability usage as building materials. The thermal conductivities of disc made from Adobe-Quartz chippings were determined. The values of the thermal conductivities obtained were between 0.6Wm-1k-1and 0.9Wm-1k-1, these values could be used to identify Adobe/Quartz as one of the engineering materials used in building construction. Adobe/Quartz was prepared in discs form of the same diameters and thicknesses and was also compressed under the same pressure of 15 atmospheres (100: 0, 95: 5and 80: 20). The average values of the thermal conductivities were between 0.07Wm-1Ҡ-1 and 0.93Wm-1Ҡ-1, for sample contained the proportion of (80:20) and the sample of ratio (95:5). MATLAB 7.0 and EXCEL software were used in the various computations, especially in determining dT/dt, Root mean square error (RMSE), Curve fittings parameter and the correlation coefficient, R2. An average correlation coefficient of 0.78 was existed between Adobe-Quartz ratio and thermal conductivity. The equation, y = -0.11x2 + 0.01x + 1.03 is the general equation that can be used for the prediction of average thermal conductivity at various ratios. Where y is the average thermal conductivity and x here signifies the ratios. This also indicates that compacted Adobe-Quartz of low density will be a suitable thermal insulator when used as aggregates in walls.

scholarly journals Determination of thermal conductivity of rocks samples using fabricated equipment

2008 ◽  
Vol 12 (2) ◽  
pp. 119-128 ◽  
Author(s):  
Olusola Fasunwon ◽  
John Olowofela ◽  
Ojok Ocan ◽  
Olukayode Akinyemi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Ambient Temperature ◽  
Experimental Techniques ◽  
Transient Method ◽  
Developing Nation ◽  
Rock Samples ◽  
Thermal Conductivity Of Rock

The aim of the paper is to describe how inexpensive/simple physics equipment was fabricated and used in the determination of thermal conductivity of rock samples. We used the experimental techniques known as transient method of measuring thermal properties of rock samples at ambient temperature. We investigated samples found in five locations/region (Ewekoro, Ile-Ife, Igara, Ago-Iwoye, Abeokuta) in South western Nigeria. Those samples are limestone, dolerite, marble, gneiss, and granite. Although the samples are multi-mineral as revealed by photomicrograph, the thermal conductivity results obtained 1.40, 1.50, 1.57, 1.75, and 2.94 W/m?C, respectively, are found to be consistent with the ones in literature where highly expensive and sophisticated (not easily affordable in developing nation) equipment are used. .

scholarly journals Thermal Properties of Plaster Reinforced with Date Palm Fibers

2020 ◽  
Vol 16 (2) ◽  
pp. 259-266
Author(s):  
Mokhtar Rachedi ◽  
Abdelouahed Kriker
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Date Palm ◽  
Thermal Effusivity ◽  
Date Palm Fibers ◽  
Different Types ◽  
Local Materials ◽  
Significant Point

AbstractThis study aims both to investigate the thermal properties of plaster reinforced with date palm fibers and local natural resources valorization to batter using materials construction. For that, studying the effect of addition date palm fibers on the plaster's thermal properties is a significant point. In this work, we measured effective thermal conductivity, thermal diffusivity, specific heat, and thermal effusivity of date palm fibers reinforced plaster has been studied by CT meter. Samples configurations with four lengths (10 mm - 40 mm) and four-weight ratios (0.5 % - 2 %) of palm fibers in plaster. The results obtained demonstrate that an increase in the fraction of date palm fiber engenders to a significant decrease in the thermal conductivity, thermal diffusivity, and effusivity, even an increase for the specific heat of different types of samples. Finally, this study is a contribution to the valorization of local materials in southern Algeria, and results encourage the use of plaster and date palm fibers in the field of construction and go to eco-friendly buildings.

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