Prediction of Sound-Insulating Properties of Cellular Concrete Composites

2021 ◽  
pp. 47-52
Author(s):  
V. N. Tarasenko ◽  
J. V. Denisova ◽  
N. D. Chernysh
Keyword(s):  
Insulating Properties ◽  
Cellular Concrete

Improvement of Heat-Insulating Properties of Foam Concrete by Means of Mineral Additives

2018 ◽  
Vol 771 ◽  
pp. 31-36 ◽  
Author(s):  
Ekaterina A. Barteneva ◽  
Mikhail A. Ylesin ◽  
Nikolay A. Mashin ◽  
Dmitry V. Dubrov
Keyword(s):  
Thermal Conductivity ◽  
Porous Structure ◽  
Heat Conductivity ◽  
Thermal Conductivity Coefficient ◽  
Economic Effect ◽  
Foam Concrete ◽  
Complete Replacement ◽  
Mineral Additives ◽  
Insulating Properties ◽  
Cellular Concrete

Foam concrete solidifying in natural conditions significantly shrinks, which causes deterioration of the porous structure and thus the increase in the heat conductivity of the material. One of the solutions for this problem is application of mineral modifiers. As the mineral modifiers the authors used the production waste – mineral additives (wollastonite, diopside) at natural dispersive capacity, as well as milled down to 300 and 600 m2/kg of specific surface. The application of perlite microspheres in foam concrete was investigated. The thermal conductivity coefficient was defined by rapid method. The optimal composition of the mixture for manufacturing foam concrete products with mineral additives ensures the decrease in the heat conductivity coefficient by 41-43% compared to the reference composition. At complete replacement of fly-ash aggregate by perlite microspheres the thermal conductivity coefficient decreases down to 0.062 W/ (m×°С). The economic effect of application of the developed foam concrete with the additive of wollastonite and diopside compared with the foam concrete presented on the market is equal to 259 / 388 RUB/m2 of an erected structure at the density of D300/ D400 respectively. Thus, directed regulation of the porous structure of cellular concrete leads to significant improvement of stability of the foam concrete mixture, which makes the prerequisites to the decrease in the thermal conductivity of the material and positive technical and economical results.

Structure and Orientation of As Precipitates in LT-MBE Grown GaAs

1991 ◽  
Vol 49 ◽  
pp. 900-901 ◽  
Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber
Keyword(s):  
Transport Properties ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Low Temperatures ◽  
Lattice Parameter ◽  
Crystalline Quality ◽  
Insulating Properties ◽  
Lt Gaas

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.

Insulating Composites Made from Sulfur, Canola Oil, and Wool

2020 ◽  
Author(s):  
Israa Bu Najmah ◽  
Nicholas Lundquist ◽  
Melissa K. Stanfield ◽  
Filip Stojcevski ◽  
Jonathan A. Campbell ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Canola Oil ◽  
Building Blocks ◽  
Atom Economy ◽  
Flame Resistance ◽  
Sustainable Building ◽  
Second Stage ◽  
Wool Fibers ◽  
Insulating Properties ◽  
Polysulfide Polymer

An insulating composite was made from the sustainable building blocks wool, sulfur, and canola oil. In the first stage of the synthesis, inverse vulcanization was used to make a polysulfide polymer from the canola oil triglyceride and sulfur. This polymerization benefits from complete atom economy. In the second stage, the powdered polymer is mixed with wool, coating the fibers through electrostatic attraction. The polymer and wool mixture is then compressed with mild heating to provoke S-S metathesis in the polymer, which locks the wool in the polymer matrix. The wool fibers impart tensile strength, insulating properties, and flame resistance to the composite. All building blocks are sustainable or derived from waste and the composite is a promising lead on next-generation insulation for energy conservation.

Technological features of manufacturing of dispersion-reinforced cellular concrete

2020 ◽  
pp. 118-131
Author(s):  
Valeriy Strotskiy ◽  
◽  
Sergey Zimin ◽  
Aleksey Krokhin ◽  
Valentina Stepanova ◽  
...  
Keyword(s):  
Cellular Concrete

Effect of photon irradiation on structural, dielectric, and insulating properties of Ba0.60Sr0.40TiO3 thin films

2008 ◽  
Vol 92 (21) ◽  
pp. 212906 ◽  
Author(s):  
Adrian Podpirka ◽  
M. W. Cole ◽  
Shriram Ramanathan
Keyword(s):  
Thin Films ◽  
Photon Irradiation ◽  
Insulating Properties

scholarly journals Study on the Effect of Helium on the Dielectric Strength of Medium-Voltage Vacuum Interrupters

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3742
Author(s):  
Paweł Węgierek ◽  
Michał Lech ◽  
Damian Kostyła ◽  
Czesław Kozak
Keyword(s):  
Comparative Analysis ◽  
Test Object ◽  
Pressure Range ◽  
Dielectric Strength ◽  
Working Pressure ◽  
Medium Voltage ◽  
Vacuum Interrupter ◽  
Working Medium ◽  
Pure Helium ◽  
Insulating Properties

This paper presents the results of a comparative analysis of the dielectric strength of disconnecting vacuum interrupters operating on air and helium. The breakdown voltage Ud was measured in the pressure range from 8.0 × 10−4 Pa to 3.0 × 101 Pa for air and from 8.0 × 10−4 Pa to 7.0 × 102 Pa for helium, while varying the interelectrode distance from 1.0 to 5.0 mm. Dedicated laboratory workstations were used to determine the actual pressure values in the vacuum interrupters tested and to precisely measure and record the dielectric strength results of the test object. It was found that the helium-filled vacuum interrupter maintains its full dielectric strength in significantly larger pressure ranges, while the air-filled vacuum interrupter loses its insulating properties. Thus, it is possible to make vacuum interrupters based on the working medium associated with pure helium, with larger working pressure ratings. Under such conditions, it is easier to maintain the tightness of the device and to limit cut-off currents and overvoltages associated with vacuum switchgear.

scholarly journals Sound-Absorbing and Thermal-Insulating Properties of Cement Composite Based on Recycled Rubber from Waste Tires

2021 ◽  
Vol 11 (6) ◽  
pp. 2725
Author(s):  
Jakub Svoboda ◽  
Tomáš Dvorský ◽  
Vojtěch Václavík ◽  
Jakub Charvát ◽  
Kateřina Máčalová ◽  
...  
Keyword(s):  
Building Materials ◽  
Absorption Capacity ◽  
Acoustic Properties ◽  
Strength Characteristics ◽  
Cement Composites ◽  
Waste Tires ◽  
Natural Aggregate ◽  
Thermal Insulating ◽  
Recycled Rubber ◽  
Insulating Properties

This article describes an experimental study aimed at investigating the potential use of recycled rubber granulate from waste tires of fractions 0/1 and 1/3 mm in cement composites as a 100% replacement for natural aggregates. The use of waste in the development and production of new building materials represents an important aspect for the sustainability and protection of the environment. This article is focused on the sound-absorbing and thermal-insulating properties of experimental cement composites based on recycled rubber from waste tires. The article describes the grain characteristics of recycled rubber, sound absorption capacity, thermal conductivity and strength characteristics. The results of this research show that the total replacement of natural aggregate with recycled rubber in cement composites is possible. Replacing natural aggregate with recycled rubber has significantly improved the thermal and acoustic properties of the prepared cement composites, however, at the same time; there was also the expected decrease in the strength characteristics due to the elasticity of rubber.

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