Thermal Insulation Blocks Made of Sunflower Pith Particles and Polysaccharide-Based Binders: Influence of Binder Type and Content on Their Characteristics

2022 ◽  
Author(s):  
Aurélie Laborel-Préneron ◽  
Clara Ampe ◽  
Laurent Labonne ◽  
Camille Magniont ◽  
Philippe Evon
Keyword(s):  
Water Resistance ◽  
Mechanical Test ◽  
Absorption Capacity ◽  
Binder Content ◽  
Dry Density ◽  
Capillary Absorption ◽  
Cold Compression ◽  
Binder Type ◽  
Order Of Magnitude ◽  
Thermal Conductivities

Co-product of sunflower cultivation, pith of stem has a little exploited insulating potential. Blocks in which pith particles are glued together using a starch-based binder have already been obtained. However, they are highly water-sensitive. Replacing this binder with others has been considered here. Polysaccharide-based binders were tested, chosen for their more hydrophobic character: sodium alginate, chitosan, Citrus pectin, and a modified starch. Like starch, these binders are physically binding. They are first solubilised in water (except chitosan, dissolved in 2% acetic acid). The solution is then mixed with pith particles before cold compression molding for 90 s. A 10% binder content was initially considered. The blocks were all cohesive with a dry density from 36 to 42 kg/m3). Their performances were assessed through water absorption capacity and resistance via capillary absorption tests on wet sponges, mechanical test and thermal conductivity. Chitosan and pectin-based blocks show the best properties, particularly concerning water resistance and mechanical properties. The pectin-based block has improved its elastic modulus by 40% compared to a starch-based block. The pectin-based block in its case absorbs 2.7 times less water than starch. Finally, thermal conductivities of pectin and chitosan-based pith blocks are in the same order of magnitude as for starch (39.8-40.1 mW/m.K), and close to values from commercial materials (e.g., polystyrene). Pectin and chitosan were also tested at three rates (5%, 10% and 15%). A significant improvement in the blocks' compressive strength was observed with the increase in binder rate, while thermal conductivities varied little.

Through-Plane Thermal Conductivity of PEMFC Porous Transport Layers

2010 ◽  
Vol 8 (2) ◽  
Author(s):  
Odne S. Burheim ◽  
Jon G. Pharoah ◽  
Hannah Lampert ◽  
Preben J. S. Vie ◽  
Signe Kjelstrup
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Residual Water ◽  
Order Of Magnitude ◽  
Thermal Conductivities

We report the through-plane thermal conductivities of the several widely used carbon porous transport layers (PTLs) and their thermal contact resistance to an aluminum polarization plate. We report these values both for wet and dry samples and at different compaction pressures. We show that depending on the type of PTL and the existence of residual water, the thermal conductivity of the materials varies from 0.15 W K−1 m−1 to 1.6 W K−1 m−1, one order of magnitude. This behavior is the same for the contact resistance varying from 0.8 m2 K W−1 to 11×10−4 m2 K W−1. For dry PTLs, the thermal conductivity decreases with increasing polytetrafluorethylene (PTFE) content and increases with residual water. These effects are explained by the behavior of air, water, and PTFE in between the PTL fibers. It is also found that Toray papers of differing thickness exhibit different thermal conductivities.

Determination of Thermal Conductivity of Soils: A Need for Computing Heat Loss Through Buried Submarine Pipelines

1982 ◽  
Vol 22 (04) ◽  
pp. 558-562 ◽  
Author(s):  
P.C. Rawat ◽  
S.L. Agarwal
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Crude Oil ◽  
Rheological Properties ◽  
Heat Loss ◽  
Experimental Results ◽  
Dry Density ◽  
Empirical Relationships ◽  
Thermal Conductivities

Abstract An important parameter required for computing heat loss through buried submarine pipelines transporting crude oil is the thermal conductivity of soils. This paper describes an apparatus designed for determination of the thermal conductivity of soils at the desired moisture/ density condition in the laboratory under steady-state conditions. Experimental results on the three soils studied show that thermal conductivity increases as dry density increases at a constant moisture content and that it increases as water content increases at constant dry density. These results confirm the trends isolated earlier by Kersten. The experimental results are compared with the available empirical relationships. Kersten's relation is observed to predict the thermal conductivity of these soils reasonably. The predictions from Makowski and Mochlinski's relation (quoted by Szilas) are not good but improve if the sum of silt and clay fractions is treated as a clay fraction in the computation. Introduction Submarine pipelines are used extensively for transporting crude oil from offshore to other pipelines offshore or onshore. These pipelines usually are steel pipes covered with a coating of concrete. They often are buried some depth below the mudline. The rheological properties of different crude oils vary, and their viscosities increase with a decrease in temperature. Below some temperature, the liquid oil tends to gel. Therefore, for efficient transportation, the crude must be at a relatively high temperature so that it has a low viscosity. The temperature of the soil/water system surrounding a submarine pipeline is usually lower than that of oil. This temperature difference induces heat to flow from the oil to the environment, and the temperature of the oil decreases as it travels along the length of the pipeline. One must ensure that this temperature reduction does not exceed desirable limits dictated by the rheological properties of oil and by the imperatives of efficient economic properties of oil and by the imperatives of efficient economic transportation. Thus the analytical problem is to predict the temperature of crude in the pipeline some distance away from the input station. To do so, knowledge of the overall heat transfer coefficient for the pipeline is required, for which, in turn, it is necessary to know the thermal conductivities of the oil, the pipeline materials and its coating, and the soil. This paper presents thermal conductivities of soils determined in the laboratory under steady-state conditions and also presents a comparison of the test results of three soils with values determined from existing empirical relationships. Literature Review Heat moves spontaneously from higher to lower temperatures. In a completely dry porous body, transmission of heat can take place not only by conduction through the solid framework of the body and the air in the pores but also by convection and radiation between the walls of a pore and by macro- and microdistillation. In soils, however, it can be ascribed essentially to conduction, a molecular phenomenon that can be expressed in terms of experimentally determined coefficients of conductivity or resistivity, although these actually may include microdistillation and other mechanisms. SPEJ p. 558

scholarly journals Performance Assessment of Waste Fiber-Reinforced Mortar

2012 ◽  
Vol 730-732 ◽  
pp. 617-622 ◽  
Author(s):  
Cristiana Gonilho-Pereira ◽  
Paulina Faria ◽  
Raul Fangueiro ◽  
Ana Martins ◽  
Pedro Vinagre ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Dynamic Modulus ◽  
Hydrated Lime ◽  
Capillary Absorption ◽  
Fibrous Materials ◽  
Fiber Reinforced ◽  
Through Flow ◽  
Flow Table ◽  
Lime Mortars ◽  
Binder Type

In this paper an experimental work is presented which main objective is the evaluation of the influence of different percentages of waste fibrous materials usage on the performance of fiber-reinforced mortars. Moreover, the influence of binder type is evaluated. Therefore mortars were produced with two different binders – cement and powder hydrated lime. Mortars performance evaluation was carried out through flow table and plunger penetration consistency, dynamic modulus of elasticity, flexural and compressive strength, capillary absorption, drying index and adherence tests. The benefits revealed in some characteristics of both mortars by the use of waste fibers are discussed.

scholarly journals New insulation fiberboards from sunflower cake with improved thermal and mechanical properties

2015 ◽  
Vol 3 (2) ◽  
pp. 194 ◽  
Author(s):  
Philippe EVON ◽  
Justine Vinet ◽  
Matthieu Rigal ◽  
Laurent Labonne ◽  
Virginie Vandenbossche ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Heat Insulation ◽  
Binder Content ◽  
Medium Density ◽  
Thermal And Mechanical Properties ◽  
Board Density ◽  
Lignocellulosic Fibers ◽  
Reinforcing Fillers ◽  
Binder Type ◽  
Sunflower Cake

New thermal insulation fiberboards were manufactured by compression molding from a cake generated during the sunflower biorefinery. Fiberboards were cohesive mixtures of a natural binder and lignocellulosic fibers from sunflower cake. The natural binder ensured the board cohesion, and fibers acted as reinforcing fillers. The influence of molding conditions, i.e. binder type and binder content, on board density, mechanical and heat insulation properties was examined. The medium-density board containing 20% starch-based binder was a good compromise between mechanical and heat insulation properties (78 mW/m K thermal conductivity). It could be positioned on walls and ceilings for thermal insulation of buildings.

Through-Plane Thermal Conductivity of PEMFC Porous Transport Layers

2010 ◽  
Author(s):  
Odne S. Burheim ◽  
Jon G. Pharoah ◽  
Hannah Lampert ◽  
Preben J. S. Vie ◽  
Signe Kjelstrup
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Residual Water ◽  
Order Of Magnitude ◽  
Thermal Conductivities

We report the through-plane thermal conductivities of the several widely used carbon porous transport layers (PTLs or GDLs) and their thermal contact resistance to an aluminium polarisation plate. We report these values both for wet and dry samples and at different compaction pressures. We show that depending on the type of PTL and possible residual water, the thermal conductivity of the materials varies from 0.15 to 1.6 W K−1 m−1 — one order of magnitude. This behaviour is the same for the contact resistance varying from 0.8 to 11 10−4 m2 K W−1. For dry PTLs the thermal conductivity decreases with increasing PTFE content and increases with residual water. These effects are explained by the behaviour of air, water and PTFE in between the PTL fibres.

scholarly journals Using artificial neural network to predict dry density of soil from thermal conductivity

2017 ◽  
Vol 64 (3) ◽  
pp. 169-180 ◽  
Author(s):  
Oluseun Adetola Sanuade ◽  
Rasheed Babatunde Adesina ◽  
Joel Olayide Amosun ◽  
Akindeji Opeyemi Fajana ◽  
Olayiwola Grace Olaseeni
Keyword(s):  
Neural Network ◽  
Thermal Conductivity ◽  
Artificial Neural Network ◽  
Dry Density ◽  
Grid Pattern ◽  
Southwestern Nigeria ◽  
Ogun State ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
Thermal Conductivities

Abstract Artificial neural network (ANN) was used to predict the dry density of soil from its thermal conductivity. The study area is a farmland located in Abeokuta, Ogun State, Southwestern Nigeria. Thirty points were sampled in a grid pattern, and the thermal conductivities were measured using KD-2 Pro thermal analyser. Samples were collected from 20 sample points to determine the dry density in the laboratory. MATLAB was used to perform the ANN analysis in order to predict the dry density of soil. The ANN was able to predict dry density with a root-mean-square error (RMSE) of 0.50 and a correlation coefficient (R2) of 0.80. The validation of our model between the actual and predicted dry densities shows R2 to be 0.99. This fit shows that the model can be applied to predict the dry density of soil in study areas where the thermal conductivities are known.

scholarly journals Approaching the “cold curve” in laser-driven shock wave experiment of a matter precompressed by a partially perforated diamond anvil

2012 ◽  
Vol 31 (1) ◽  
pp. 73-79 ◽  
Author(s):  
N. Nissim ◽  
S. Eliezer ◽  
M. Werdiger ◽  
L. Perelmutter
Keyword(s):  
Shock Wave ◽  
Diamond Anvil Cell ◽  
Compression Curve ◽  
One Dimensional ◽  
Cold Compression ◽  
Relative Contribution ◽  
Order Of Magnitude ◽  
Diamond Anvil ◽  
Hugoniot Curves ◽  
Shock Wave Experiment

AbstractThis paper suggests a novel route to approach the cold compression curve in laser-plasma induced shock waves. This effect is achieved with a precompression in a diamond anvil cell (DAC). In order to keep the necessary structure of one dimensional shock wave it is required to use a diamond anvil cell with a partially perforated diamond anvil. Precompression pressures of about 50 GPa, that are an order of magnitude higher than the currently reported pressures, are possible to obtain with presentley existing diamond anvil cell technology. The precompressed Hugoniot of Al was calculated for different precompression pressures and it was found that at precompression pressure of 50 GPa the Hugoniot follows the “cold curve” up to about 2 Mbar and 5.2 g/cc. Furthermore, the thermal relative contribution on the Hugoniot curves is calculated.

scholarly journals Use of Waste Glass as A Replacement for Raw Materials in Mortars with a Lower Environmental Impact

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1974 ◽  
Author(s):  
Viviana Letelier ◽  
Bastián I. Henríquez-Jara ◽  
Miguel Manosalva ◽  
Camila Parodi ◽  
José Marcos Ortega
Keyword(s):  
Glass Powder ◽  
Raw Materials ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Environmental Benefits ◽  
Dry Density ◽  
Capillary Absorption ◽  
Powder Size ◽  
Glass Waste

Glass waste used in mortars or concretes behaves similar to cement, with resulting environmental benefits. In this light, the behavior of glass powder of various particle sizes has been analyzed as a cement replacement in mortars, in an attempt to minimize the loss of strength and durability, and maximize the amount of materials replaced. The dry density, water accessible porosity, water absorption by immersion, capillary absorption coefficient, ultrasonic pulse velocity and both compressive and flexural strengths were studied in the mortars. Furthermore, a statistical analysis of the obtained results and a greenhouse gases assessment were also performed. In view of the results obtained, glass powder of 38 microns allows up to 30% of the cement to be replaced, due to the filler effect combined with its pozzolanic activity. Moreover, it has been observed that glass powder size is one of the factors with the greatest influence among the properties of porosity, absorption and capillarity. On the other hand, in the mechanical properties, this factor does not contribute significantly more than the amount of glass powder. Finally, the greenhouse gasses analysis shows that the incorporation of glass powder reduces the CO2 emissions associated with mortar up to 29.47%.

scholarly journals Experimental Study of the Strength Aspects of Compressed Stabilized Earth Blocks using Marble Dust, Sugarcane Bagasse Ash and Paddy Straw Fiber

2021 ◽  
Vol 889 (1) ◽  
pp. 012025
Author(s):  
Aman Verma ◽  
Tarun Sharma
Keyword(s):  
Water Absorption ◽  
Sugarcane Bagasse ◽  
Construction Material ◽  
Absorption Capacity ◽  
Waste Material ◽  
Dry Density ◽  
Paddy Straw ◽  
Marble Powder ◽  
Sugarcane Bagasse Ash ◽  
Earth Blocks

Abstract The world is facing pollution crises and these cries are due to improper disposal of waste material. This materials are Rice husk ash, bagasseash, waste marble powder, remanings of grains like rice starw and many more. Some of the waste materials can easily be disposable in the construction industry by using them in the concrete or in any other construction material. This paper deals with this waste material to be utilized in the compressed earth blocks. To study the mechanical properties of compressed soil blocks prepared by a combination of various ratios of Marble powder, paddy Straw Fiber and Sugarcane bagasse ash, the compression test, and water absorption test was performed. The marble powder is introduced in the manner to replace soil by 25%, 35%% and 45 %. Paddy Starws fibers are introducedby the replacement percentage of.6%,.8%and 1% whereas the bagasse ash is been introduced in the manner of 8%,10% and 12%This various test shows that the Marble powder Waste increase dry density which helps in increasing the compression Capacity of the brick. Whereas Paddy Straw fiber and bagasse ash decrease the dry density of brick which results in decreasingthe optimum water content of the mixof the brick. Bagasse ash and paddy straw fiber increase the water absorption capacity of the brick.

What Makes Cow-Dung Stabilised Earthen Block Water-Resistant

2022 ◽  
Author(s):  
Yask Kulshreshtha ◽  
Philip J. Vardon ◽  
Gabrie Meesters ◽  
Mark C.M. van Loosdrecht ◽  
Nelson J.A. Mota ◽  
...  
Keyword(s):  
Water Content ◽  
Water Resistance ◽  
Bet Surface Area ◽  
Dry Density ◽  
Cow Dung ◽  
African Countries ◽  
Potential Measurement ◽  
Earthen Structures ◽  
Optimum Water Content ◽  
Practical Recommendations

The water-resistance of cow-dung has made it a widely used stabiliser in traditional earthen structures in several Asian and African countries. Multiple studies have shown an improvement in water-resistance with the addition of cow-dung, but none provides insight into this behaviour. The present study investigates the water-resistance behaviour of cow-dung stabilised earthen blocks through an extensive experimental programme to identify and characterise the components of cow-dung responsible for its water-resistance. Fresh cow-dung was collected and separated into fibres (>63 μm), medium-sized microbial aggregates (1-63 μm) and small-sized microbial aggregates (0.5-7 μm). Each component was mixed with soil and samples were prepared at different water contents (optimum water content corresponding to the highest dry density and water content higher than optimum) and compacted with 2.5 MPa force to prepare compressed blocks. The water-resistance of these blocks was evaluated through the immersion and modified drip/rain test. It was found that the small-sized microbial aggregates are almost entirely responsible for water-resistance behaviour of cow-dung stabilised earthen blocks. Small-sized microbial aggregates were further characterised by gas chromatography, mercury intrusion porosimetry, N2- BET surface area, zeta potential measurement and electron microscopy. The results indicate that the small-sized microbial aggregates are composed of clay-sized negatively charged particles that are rich in fatty acids. The hydrophobicity of these particles is hypothesised to be responsible for water-resistance behaviour. These insights are further used to produce stabilised blocks that performed at least 30 times better than the unstabilised blocks in both water-resistance tests. The study concludes with practical recommendations for the use of wet cow-dung over dry cow-dung and a reduction of fibre content to increase the water-resistance of earthen blocks.

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