scholarly journals INFLUENCE OF POWDER PARTICLE SIZES OF POROUS MATERIALS ON REDUCING THE AERODYNAMIC NOISE LEVEL

Doklady BGUIR ◽  
2019 ◽  
pp. 109-116
Author(s):  
L. P. Pilinevich ◽  
M. V. Tumilovich ◽  
A. G. Kravtsov ◽  
D. M. Rumyantsev ◽  
K. V. Grib
Keyword(s):  
Particle Size ◽  
Mechanical Strength ◽  
Noise Reduction ◽  
Porous Materials ◽  
Pore Size ◽  
Noise Level ◽  
Aerodynamic Noise ◽  
Particle Sizes ◽  
Metal Powders ◽  
High Permeability

One of the main means of reducing aerodynamic noise is the use of silencers, which can be made of various porous materials, depending on the specific operating conditions. The aim of the work is to study the dependence of the noise reduction on the characteristics of porous permeable materials (PPM) obtained by vibration molding from metal powders. Such PPMs have a wide range of porosity, high permeability, mechanical strength, provide the ability to work in a wide temperature range, high corrosion resistance, and therefore find more and more widespread application in practice. When designing silencers, their pore size, permeability, mechanical strength, cost, and the chemical composition of the material are taken into account. Basic research methods – determination of noise level, powder particle size, permeability coefficient, pore size. Vibration molding of PPM samples for experimental studies was carried out on a ВЭДС 10-1А vibration bench with vibration parameters that ensured the maximum bulk density of the powder in the mold (acceleration 10 m/s2, frequency 500 Hz). Main results – the dependence of the noise reduction value on the PPM characteristics obtained by the method of vibration molding of metal powders of various grades of various particle size distribution was studied. It has been shown that the most effective damping is provided by PPM from spherical bronze powder of the БрОФ10-1 grade with particle sizes of 350–400 microns, which provides at the same time a combination of a high level of noise reduction and high permeability to air or gas. It was found that the thickness of the muff significantly affects the efficiency of noise suppression, while the minimum thickness of the muff, which provides a sufficiently high degree of noise reduction, is about 3.5 mm, therefore it is not practical to increase the thickness of the muffler material above this value.

Fabrication of Porous SiAlON Using Fe2O3 as Pore Former

2014 ◽  
Vol 804 ◽  
pp. 267-270
Author(s):  
Qing Wen Duan ◽  
Rong Zhen Liu ◽  
Hai Yun Jin ◽  
Jian Feng Yang ◽  
Zhi Hao Jin
Keyword(s):  
Particle Size ◽  
Porous Materials ◽  
Pore Size ◽  
Fracture Mode ◽  
Size Effects ◽  
Pore Diameter ◽  
Bending Strength ◽  
Thermal Reduction ◽  
Pore Former ◽  
Median Pore

Porous SiAlON ceramics were fabricated by carbo-thermal reduction nitridation method using Fe2O3 as pore former. Particle size effects of Fe2O3 were reported in this paper. The results showed that composites were composed by SiAlON, AlN and Iron Silicon phases. The median pore diameter of Sialon was affected by the composition and particle size of Fe2O3. The fracture mode of this material was intergranular. With the increase of Fe2O3 additions, the porosity of this materials increased. The bending strength of this material was reversely proportional to Fe2O3 particle size. The maximum bending strength of Porous materials with 30wt.% Fe2O3 additions (with a porosity about 65% and the pore size is about 1μm) could reach 22 MPa. The porous Sialon ceramics with a smaller pore size exhibited a higher bending strength.

Effects of Sand Bed Anti-Vibration Mount on Transmitted Noise from Portable On-Site Electricity Generator

2020 ◽  
Vol 15 (2) ◽  
pp. 8-12
Author(s):  
A.S. Aremu ◽  
T.K. Amao ◽  
O.A. Mokuolu
Keyword(s):  
Particle Size ◽  
Noise Reduction ◽  
Fine Sand ◽  
Sound Level ◽  
Sand Particle ◽  
Particle Sizes ◽  
Noise Levels ◽  
Noise Measurements ◽  
Level Meter ◽  
Vibration Noise

This study investigated the effect of different particle sizes of sand bed anti-vibration mount on transmitted noise from a portable on-site electricity generator. Ten sand bed anti-vibration mounts, 650mm x 650mm in cross section and 75mm thickness were prepared with particle sizes ranging from 0.09 to 2.30mm. Noise measurements were taken in the four cardinal directions using Extech HD600 digital sound level meter. The results of the study showed that the ability of the sand particles to dampen vibration noise from the portable electricity generator reduces with increase in particle size. The sand bed anti-vibration mounts reduced noise levels by 0.11 to 2.78 dB(A). However, fine sand bed of particle size 0.09mm and 0.15mm exhibited superiority in noise reduction over all other sand beds. In order to achieve appreciable noise reduction, the use of ISO 14688-1:2002 fine sand category is recommended as anti-vibration mount in combination with other damping methods. Keywords: Electricity generator, noise, sand, particle size and attenuation

Microstructure Designing of Porous β-Tricalcium Phosphate for Control of Reactions in the Bone

2007 ◽  
Vol 361-363 ◽  
pp. 989-992 ◽  
Author(s):  
Koji Ioku ◽  
Masanobu Kamitakahara ◽  
Giichiro Kawachi ◽  
Yoshinori Gonda ◽  
Takatoshi Okuda ◽  
...  
Keyword(s):  
Particle Size ◽  
Bone Graft ◽  
Porous Materials ◽  
Pore Size ◽  
Hydrothermal Method ◽  
Tricalcium Phosphate ◽  
Molar Ratio ◽  
Graft Material ◽  
Porous Hydroxyapatite ◽  
Unique Method

Porous materials of β-tricalcium phosphate (β-Ca3(PO4)2; β-TCP) were prepared from porous hydroxyapatite (Ca10(PO4)6(OH)2; HA) with calcium deficient composition of Ca/P molar ratio of 1.50 synthesized by hydrothermal method. The porous β-TCP was composed of rod-shaped particles of about 10-20 μm in length. Rod-shaped particles were locked together to make micro-pores, and the size of micro-pores formed by tangling of rod-shaped particles was about 0.1-0.5 μm. The particle size and micro-pore size could be controlled by our unique method. It must be suitable for the bone graft material and as the scaffold of cultured bone.

Study on Property of Ti-Based Nonevoparobal Getter

2010 ◽  
Vol 146-147 ◽  
pp. 212-216
Author(s):  
Teng Fei Li ◽  
Yan Zhang ◽  
Xiu Ying Wei ◽  
Peng Yuan ◽  
Chang Hui Mao
Keyword(s):  
Particle Size ◽  
Mechanical Strength ◽  
Titanium Powder ◽  
Sorption Properties ◽  
Average Particle ◽  
Particle Sizes ◽  
Metallurgical Technology ◽  
Titanium Powders ◽  
Different Gases ◽  
Sorption Characteristics

The getters composed with Titanium and Zr-V-Fe were prepared by conventional powder metallurgical technology. The sorption properties and mechanical strength of the Ti-Zr-V-Fe getter prepared with three different average particle sizes of Titanium powder were investigated. The results showed that the smaller Titanium powders particle size can effectively improve the property of the nonevoparobal getter, but if particle size is too small, the sorption of the getter will decrease. The getter which was added with Titanium powder of 48μm has the best hydrogen sorption capability. With the decrease of the size of Titanium powder, mechanical strength will be improved remarkably. In the paper, the sorption characteristics for different gases were analyzed initially and the understanding for Zr-based getter is more extensive. The results show that the getters can adsorb activated gases, such as H2, N2 and CO. The pumping speed for H2 is best than that for N2 and CO.

scholarly journals Complexity Simulation on Application of Asymmetric Bionic Cross-Section Rod in Pantographs of High-Speed Trains

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yan Cao ◽  
Yu Bai ◽  
Qiangfeng Wang
Keyword(s):  
Noise Reduction ◽  
Porous Materials ◽  
Cross Section ◽  
High Speed ◽  
Aerodynamic Resistance ◽  
Aerodynamic Noise ◽  
Practical Application ◽  
Bionic Design ◽  
High Speed Trains ◽  
Bionic Structure

Ground transportation means and aircrafts with high-speed running are composed of many rod components. Aerodynamic noise generated therefrom is very outstanding. Reduction of the aerodynamic noise of rods becomes a hot topic in recent years. Most reported studies are tentative researches on aerodynamic noise of a pantograph or involve noise reduction of the pantograph with using porous materials or reshaping rod surfaces. Through using porous materials and reshaping rod surface, the aerodynamic noise of pantograph can be reduced to a certain extent, but the aerodynamic resistance will be increased and it is not convenient for practical application in engineering. Regarding this situation, the paper explores noise reduction performance of a feather on the back of a carrier pigeon and conducts the bionic design on rod surface. Through numerical simulation, the paper researches noise reduction performance of the bionic structure on the rod surface, reveals the mechanism of bionic noise reduction, and explores noise reduction effects of bionic structural rods on pantographs of the high-speed trains.

Effect of the Particle Size of an Ash from Sugarcane Bagasse in the Properties of Red Ceramics

2006 ◽  
Vol 530-531 ◽  
pp. 538-543 ◽  
Author(s):  
Monica Castoldi Borlini Gadioli ◽  
J.L.C.C. Mendonça ◽  
R.A. Conte ◽  
Daltro Garcia Pinatti ◽  
Carlos Maurício Fontes Vieira ◽  
...  
Keyword(s):  
Particle Size ◽  
Mechanical Strength ◽  
Water Absorption ◽  
Sugarcane Bagasse ◽  
Particle Sizes ◽  
Technological Properties ◽  
Kaolinitic Clay ◽  
Red Ceramics

The influence of the particle size of an ash from sugarcane bagasse on the properties of incorporated red ceramics was investigated. Mixtures of kaolinitic clay from the municipal area of Campos of Goytacazes-RJ were prepared with additions of 0, 5 and 10% in weight of ashes from sugarcane bagasse. Ashes with different particle sizes lower than 149 μm (100 mesh), 75 μm (200 mesh) and 44 μm (325 mesh), were used in each incorporated composition. Specimens were 20 MPa uniaxially press-molded and sintered at 900 and 1050°C. The firing technological properties evaluated were diametrical shrinkage, water absorption and mechanical strength by diametrical compression. The results showed that the ash incorporation caused significant changes in the ceramic properties.

scholarly journals Evaluation of different fly ash samples on the production of alkali-activated materials

2021 ◽  
Vol 14 (6) ◽  
Author(s):  
Adriano Galvão Souza Azevedo ◽  
Luis Fernando Tonholo Domingos ◽  
Kurt Strecker
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Mechanical Strength ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Curing Time ◽  
Specific Mass ◽  
Fe2o3 Content ◽  
Alkali Activated

abstract: In this work, different samples of fly ash (FA-A and FA-B) classified as type F as used to produce the AAM samples. The FA-A presented a higher Fe2O3 content than FA-B, 6.1 to 3.8 wt.%, and a slightly higher SiO2/Al2O3 ratio of 3.52 in comparison to 3.34 of FA-B. The average particle size (D50) of fly ash A was 19.7 µm and of fly ash B 30.8 µm, while the specific mass of the ashes A and B were 2.38 and 2.21 g/cm3, respectively. The results revealed that the mechanical strength of the AAM produced with fly ash A was higher than fly ash B, close to 80 and 44 MPa, respectively. The variation of the strength has been attributed to the different SiO2/Al2O3 ratios and different particle sizes. The mechanical strength decreased with increasing curing time, which is attributed to excess alkali in the system. Only very small differences in porosity and density have been found.

Microstructure and Interconnections Characteristics of Titanium Foam

2016 ◽  
Vol 687 ◽  
pp. 25-32 ◽  
Author(s):  
Krzysztof Pałka ◽  
Grzegorz Adamek ◽  
Jarosław Jakubowicz
Keyword(s):  
Particle Size ◽  
Chemical Reactions ◽  
Open Porosity ◽  
Spherical Particles ◽  
Particle Sizes ◽  
High Permeability ◽  
Titanium Particle ◽  
Average Size ◽  
Titanium Foam ◽  
To Receive

Titanium foams are widely used as biomaterials and potentially as a twin skinned, sandwich, structures for aerospace structures, filter or a catalyst or catalysts carrier for chemical reactions. The porosity is particularly important for tissues ingrowth and vascularity. Open porosity is essential in the case of flow-on machines. The distribution and size of pores is significant to achieve a uniform material effort and ensure to receive an appropriate hydraulic properties.The aim of this study was to determine the effect of titanium particle size and the amount of porogen on the microstructure and the size of pore interconnections in titanium foams made using saccharose as the space holder material.The paper characterizes titanium foam, made from the Grade 1 Ti powders (Alfa Aesar) with a particle sizes of 0.150 mm and 0.044 mm (separately) and spherical particles of saccharose (Pfeifer & Langen) having an average size of 0.7 ÷ 0.9 mm, as a porogen. There was prepared a mixture of powders of the proposed porosity of 50, 60 and 70%. Summarizing 6 mixtures were prepared. After sintering there were received specimens having a diameter of 8 mm and a height of 5 mm. Microstructure analysis was performed using the microtomography Skyscan 1172 (Bruker microCT) and the CTAn software (Bruker microCT).The results indicate the uniform pore distribution and size of the interconnections allowing high permeability.

scholarly journals Aerodynamic Noise Reduction using Porous Materials and their Application to High-speed Pantographs

2009 ◽  
Vol 50 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Takeshi SUEKI ◽  
Mitsuru IKEDA ◽  
Takehisa TAKAISHI
Keyword(s):  
Noise Reduction ◽  
Porous Materials ◽  
High Speed ◽  
Aerodynamic Noise
Sign in / Sign up

Export Citation Format

Share Document