scholarly journals Materiale compozite pe baza de deseuri de beton celular autoclavizat si rasina poliesterica nesaturata

2019 ◽  
Vol 56 (1) ◽  
pp. 256-260
Author(s):  
Gelu Coman ◽  
Gabriel-Bogdan Carp ◽  
Ion Ion ◽  
Alina Ceoromila ◽  
Nicusor Baroiu
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Thermal Resistance ◽  
Water Absorption ◽  
Unsaturated Polyester ◽  
Absorption Capacity ◽  
Insulation Material ◽  
Water Absorption Capacity ◽  
The Matrix ◽  
Influence Of Water

This paper presents an experimental study on the potential use of new type of composite as insulation material. The composite material (AACW-UPR) was synthesised through mixture between the Autoclaved Aerated Concrete Waste (AACW) as filler and Unsaturated Polyester Resin (UPR) as matrix. Several samples of the composite material with different UPR concentrations (50 and 70 vol.%) and different AACW particle size (0.2-1 mm, 1.5-2.5 mm, 3-6 mm) were prepared. The thermal behaviour and the water absorption capacity of the AACW-UPR composite materials were studied. Also, the influence of water absorption capacity on thermal resistance and thermal conductivity was studied. During the investigations we noticed the following: good chemical compatibility between the AACW particles and the UPR matrix; a decrease in thermal conductivity for samples with 50 vol.% UPR and inserted particles size between 3-6 mm and an increase in water absorption capacity with the increase in the filler content in the matrix. The increasing water absorption capacity determined a decrease in thermal resistance and a reduction of the composite features as insulating material.

Prediction of effective thermal conductivity of multicomponent tribocomposites taking into account contact thermal resistance between inclusions and matrix

2020 ◽  
pp. 36-40
Author(s):  
I.V. Lavrov ◽  
A.A. Kochetygov ◽  
V.V. Bardushkin ◽  
A.P. Syichev ◽  
V.B. Yakovlev
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Field Approximation ◽  
Effective Field ◽  
Contact Thermal Resistance ◽  
Model Calculations ◽  
Spherical Inclusions ◽  
The Matrix

A method is proposed for predicting the effective thermal conductivity of a matrix composite with several types of spherical inclusions with contact thermal resistance at the boundary of the matrix and inclusions. The method is based on a generalized effective-field approximation for an inhomogeneous medium with inclusions with a shell. Model calculations were performed for a matrix tribocomposite with two types of inclusions. Keywords: effective thermal conductivity, contact thermal resistance, composite material, matrix, inclusion with a shell, Maxwell—Garnett approximation, generalized effective-field approximation. [email protected]

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).

The effect of sugar beet fiber addition on the chemical properties of tortilla chips

2012 ◽  
pp. 385-388 ◽  
Author(s):  
Azadeh Saadatmandi ◽  
Mohammad Elahi ◽  
Reza Farhoosh ◽  
Mahdi Karimi
Keyword(s):  
Sugar Beet ◽  
Water Absorption ◽  
Protein Content ◽  
Chemical Properties ◽  
Absorption Capacity ◽  
Ash Content ◽  
Oil Absorption ◽  
Water Absorption Capacity ◽  
Overall Acceptability ◽  
Tortilla Chips

The incorporation of sugar beet fiber (0–5%) to tortilla chips and the effects on the chemical and sensory properties were studied. Addition of sugar beet fiber (SBF) led to an increasing of water absorption capacity, ash content and darkness while lowering the protein content and oil absorption. Sensory evaluation showed that the overall acceptability of tortilla chips reduces if adding more than 2% SBF.

scholarly journals Water Absorption Capacity Determines the Functionality of Vital Gluten Related to Specific Bread Volume

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 228
Author(s):  
Marina Schopf ◽  
Katharina Anne Scherf
Keyword(s):  
Water Absorption ◽  
Water Content ◽  
Wheat Flour ◽  
Specific Volume ◽  
Disulfide Bonds ◽  
Protein Composition ◽  
Absorption Capacity ◽  
Water Absorption Capacity ◽  
Water Addition ◽  
Wheat Flours

Vital gluten is often used in baking to supplement weak wheat flours and improve their baking quality. Even with the same recipe, variable final bread volumes are common, because the functionality differs between vital gluten samples also from the same manufacturer. To understand why, the protein composition of ten vital gluten samples was investigated as well as their performance in a microbaking test depending on the water content in the dough. The gluten content and composition as well the content of free thiols and disulfide bonds of the samples were similar and not related to the specific bread volumes obtained using two dough systems, one based on a baking mixture and one based on a weak wheat flour. Variations of water addition showed that an optimal specific volume of 1.74–2.38 mL/g (baking mixture) and 4.25–5.49 mL/g (weak wheat flour) was reached for each vital gluten sample depending on its specific water absorption capacity.

The Estimation of Thermal Conductivity for Alumina-Epoxy Composite Material with High Filling Volume Fraction

2014 ◽  
Vol 918 ◽  
pp. 21-26
Author(s):  
Chen Kang Huang ◽  
Yun Ching Leong
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Composite Materials ◽  
Physical Model ◽  
Electron Scattering ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
The Matrix ◽  
Transport Theorem ◽  
Good Agreement

In this study, the transport theorem of phonons and electrons is utilized to create a model to predict the thermal conductivity of composite materials. By observing or assuming the dopant displacement in the matrix, a physical model between dopant and matrix can be built, and the composite material can be divided into several regions. In each region, the phonon or electron scattering caused by boundaries, impurities, or U-processes was taken into account to calculate the thermal conductivity. The model is then used to predict the composite thermal conductivity for several composite materials. It shows a pretty good agreement with previous studies in literatures. Based on the model, some discussions about dopant size and volume fraction are also made.

Comparison of Bio and Eco-technologies with Chemical Methods for Pre-treatment of Flax Fibers: Impact on Fiber Properties

2014 ◽  
Vol 9 (4) ◽  
pp. 155892501400900 ◽  
Author(s):  
Sabela Camano ◽  
Nemeshwaree Behary ◽  
Philippe Vroman ◽  
Christine Campagne
Keyword(s):  
Water Absorption ◽  
Fiber Bundle ◽  
Glass Fibers ◽  
Fiber Surface ◽  
Pectate Lyase ◽  
High Water ◽  
Absorption Capacity ◽  
Water Absorption Capacity ◽  
Flax Fibers ◽  
The Impact

Flax fibers, available as fiber bundles, are commonly used as fiber reinforcement in composite materials as a substitute for glass fibers. Pre-treatments are often necessary for improving fiber-resin adhesion, and also to facilitate fiber elementarization, and to improve fiber ability to be implemented in mechanical processes limiting fiber damages. This paper focuses on the impact of biotechnologies (effect of 2 different enzymes: a pectate lyase and a laccase) and of an ecotechnology (ultrasound with ethanol), compared to classical chemical pre-treatments (using aqueous NaOH and ammonia) on the final flax fiber bundle properties, before and after a carding process. Fiber surface properties (wettability and/or zeta potential values), fiber elementarization and mechanical properties vary with the type of treatment (chemical nature of product and conditions used). Fibers elementarised using pectate lyase and ultrasound/ethanol have a hydrophilic surface and a high water absorption capacity, and are also of highest quality in terms of increased fineness. Treatment with NaOH yields the poorest fiber bundle tenacity. Laccase enzyme yields long thick hydrophobic fibers having very low water absorption capacity, and the most neutral surface charge. Properties of flax fibers can be easily monitored using different pre-treatments resulting in fibers which would be suited for various final applications.

Effective Thermal Conductivity of Functionally Graded Particulate Nanocomposites With Interfacial Thermal Resistance

2008 ◽  
Vol 75 (5) ◽  
Author(s):  
H. M. Yin ◽  
G. H. Paulino ◽  
W. G. Buttlar ◽  
L. Z. Sun
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Functionally Graded ◽  
Interfacial Thermal Resistance ◽  
Conductivity Distribution ◽  
Consistent Model ◽  
The Matrix ◽  
Graded Material ◽  
Perfect Interface

By means of a fundamental solution for a single inhomogeneity embedded in a functionally graded material matrix, a self-consistent model is proposed to investigate the effective thermal conductivity distribution in a functionally graded particulate nanocomposite. The “Kapitza thermal resistance” along the interface between a particle and the matrix is simulated with a perfect interface but a lower thermal conductivity of the particle. The results indicate that the effective thermal conductivity distribution greatly depends on Kapitza thermal resistance, particle size, and degree of material gradient.

scholarly journals Experimental study on water level and absorption capacity in a radial well flow in a loess area

2018 ◽  
Vol 19 (5) ◽  
pp. 1313-1321
Author(s):  
Xuezhen Zhang ◽  
Aidi Huo ◽  
Jucui Wang
Keyword(s):  
Unsteady Flow ◽  
Water Absorption ◽  
Water Level ◽  
Steady Flow ◽  
Flow Injection ◽  
Absorption Capacity ◽  
Water Absorption Capacity ◽  
Analysis Method ◽  
Semi Empirical ◽  
Radial Well

Abstract In this paper, the theoretical basis for flow calculation in an injection well was discussed. It proposed that the flow rate of an injection well could be calculated referring to pumping theory and method. A mathematical model of the rising curve of water level around a radial well was established and the equation for calculating the rising curve was given. The calculation equations selected for the water absorption capacity of injection wells were explained and examples were verified and compared. The results indicated that, under the same injection conditions, the water level value calculated by the analysis method was slightly larger, but the error between the analysis method and the semi-theoretical and semi-empirical methods was small. In the processes of steady flow injection and unsteady flow injection, there was a small difference of water absorption capacity, and the former was slightly larger. The measured values of water absorption capacity were only about one-third of the calculated values based on pumping theory. Overall, the analytical solution method for predicting the rising curve of water level has priority in well injection. The semi-theoretical and semi-empirical equation for calculating water absorption capacity sifted first has priority in steady flow injection, the equation sifted second has priority in unsteady flow injection.

scholarly journals Formation of porous ceramics using cullet and biological waste of water purification

2011 ◽  
Vol 43 (1) ◽  
pp. 81-94 ◽  
Author(s):  
M. Vlasova ◽  
I. Rosales ◽  
M. Kakazey ◽  
Parra Parra ◽  
R. Guardian
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Water Purification ◽  
Sintering Temperature ◽  
Porous Ceramics ◽  
Absorption Capacity ◽  
Water Absorption Capacity ◽  
Red Clay ◽  
Temperature Range

Porous ceramics (bricks) was obtained using red clay, milled fusible cullet, and biowaste in the temperature range 950-1000?C. The high content of water in biowaste eliminates the necessity of introducing water in soft mud forming of bricks. The porosity, water absorption capacity, and mechanical properties of the prepared ceramics depend on content of milled cullet and sintering temperature.

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