Stiffening Effect of Pigments in Rubber

1945 ◽  
Vol 18 (1) ◽  
pp. 99-109
Author(s):  
S. D. Gehman
Keyword(s):  
Particle Size ◽  
Carbon Blacks ◽  
Size And Shape ◽  
Rubber Compounds ◽  
Physical Testing ◽  
The Subject ◽  
Filler Reinforcement ◽  
The Mean ◽  
Particle Size And Shape ◽  
Stiffening Effect

Abstract The use of reinforcing pigments in rubber, especially in synthetic rubber, is important in securing desirable physical properties. The earlier literature on the subject has been reviewed by Shepard, Street, and Park. Several theories were advanced to explain the effectiveness of reinforcing pigments in rubber. Some of these emphasized the importance of particle size and shape: others, the chemical composition and surface activity. The electron microscope has now furnished more reliable information on the particle size and shape of pigments, especially of carbon blacks, than was available in the earlier work2. The carbon blacks used in rubber compounding are essentially spherical; the mean diameter varies from 28 to 274 mµ for different types. Systematic studies have been carried out to show the influence of particle size and surface area on various physical testing indices used to evaluate rubber compounds. The x-ray structure of rubber stocks containing carbon black has been investigated. Several articles dealing with the theory of pigment reinforcement have appeared. This additional work has not clarified the original concepts advanced to explain filler reinforcement, but the research of Wiegand shows beyond doubt that particle size is the predominating factor in explaining differences in the properties of rubber compounded with various blacks. The present paper will attempt to explain some of the effects of pigment reinforcement of rubber, particularly increased stiffness, by simple mechanical considerations which may be regarded as extensions or extrapolations of the results of measurements on rubber in compression.

Brake Wear Particle Size and Shape Analysis of Non-Asbestos Organic (NAO) and Semi Metallic Brake Pad

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
Hussain, S. ◽  
M.K Abdul Hamid ◽  
A.R Mat Lazim ◽  
A.R. Abu Bakar
Keyword(s):  
Particle Size ◽  
Wear Particle ◽  
Brake Disc ◽  
Wear Particles ◽  
Brake Pad ◽  
Brake Pads ◽  
Size And Shape ◽  
Brake Wear Particles ◽  
Brake Wear ◽  
Particle Size And Shape

Brake wear particles resulting from friction between the brake pad and disc are common in brake system. In this work brake wear particles were analyzed based on the size and shape to investigate the effects of speed and load applied to the generation of brake wear particles. Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) was used to identify the size, shape and element compositions of these particles. Two types of brake pads were studied which are non-asbestos organic and semi metallic brake pads. Results showed that the size and shape of the particles generatedvary significantly depending on the applied brake load, and less significantly on brake disc speed. The wear particle becomes bigger with increasing applied brake pressure. The wear particle size varies from 300 nm to 600 µm, and contained elements such as carbon, oxygen, magnesium, aluminum, sulfur and iron.

scholarly journals Particle Morphology Analysis of Biomass Material Based on Improved Image Processing Method

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhaolin Lu ◽  
Xiaojuan Hu ◽  
Yao Lu
Keyword(s):  
Image Processing ◽  
Particle Size ◽  
Particle Morphology ◽  
Processing Method ◽  
Image Resolution ◽  
Ultrasonic Dispersion ◽  
Image Processing Method ◽  
Size And Shape ◽  
Nominal Size ◽  
Particle Size And Shape

Particle morphology, including size and shape, is an important factor that significantly influences the physical and chemical properties of biomass material. Based on image processing technology, a method was developed to process sample images, measure particle dimensions, and analyse the particle size and shape distributions of knife-milled wheat straw, which had been preclassified into five nominal size groups using mechanical sieving approach. Considering the great variation of particle size from micrometer to millimeter, the powders greater than 250 μm were photographed by a flatbed scanner without zoom function, and the others were photographed using a scanning electron microscopy (SEM) with high-image resolution. Actual imaging tests confirmed the excellent effect of backscattered electron (BSE) imaging mode of SEM. Particle aggregation is an important factor that affects the recognition accuracy of the image processing method. In sample preparation, the singulated arrangement and ultrasonic dispersion methods were used to separate powders into particles that were larger and smaller than the nominal size of 250 μm. In addition, an image segmentation algorithm based on particle geometrical information was proposed to recognise the finer clustered powders. Experimental results demonstrated that the improved image processing method was suitable to analyse the particle size and shape distributions of ground biomass materials and solve the size inconsistencies in sieving analysis.

Residual Stress in Bone: A Parametric Study

2008 ◽  
Author(s):  
A. Hizal ◽  
B. Sadasivam ◽  
D. Arola
Keyword(s):  
Residual Stress ◽  
Particle Size ◽  
Residual Stresses ◽  
Material Removal ◽  
Surface Deformation ◽  
Radius Of Curvature ◽  
Near Surface ◽  
Size And Shape ◽  
Air Jet ◽  
Particle Size And Shape

A preliminary study was conducted to evaluate the parametric dependence of the residual stress distributions in bone that result from an abrasive air-jet surface treatment. Specifically, the influence of particle size and shape used in the treatment on the residual stress, propensity of embedding particles and material removal were studied. Rectangular beams of cortical bone were prepared from bovine femurs and treated with aluminum oxide and glass particles with different treatment angles. Residual stresses within the bone were quantified in terms of the radius of curvature of the bone specimens measured before and after the treatments, as well as a function of time to quantify decay in the stress. The sub-surface distribution was also examined using the layer removal technique. Results showed that the particle size and shape could be used to control the amount of material removal and the magnitude of residual stress within the treated surfaces. An increase in size of the glass particles resulted in an increase in the residual stress and a decrease in material removed during the treatment. The magnitude of residual stress ranged from 22 MPa to nearly 44 MPa through modulation of the particle qualities (size and shape). A microscopic examination of the treated surfaces suggests that the residual stresses resulted primarily from near-surface deformation.

Effect of Particle Size and Shape on Flowability of FGH96 Superalloy Powder

2021 ◽  
Vol 1035 ◽  
pp. 143-151
Author(s):  
Li Chong Zhang ◽  
Wen Yong Xu ◽  
Zhou Li ◽  
Liang Zheng ◽  
Yu Feng Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Fractal Dimension ◽  
Aspect Ratio ◽  
Shape Factors ◽  
Size And Shape ◽  
Median Diameter ◽  
Powder Flowability ◽  
Effect Of Particle Size ◽  
Particle Size And Shape ◽  
Superalloy Powder

The effect of particle size and shape on flowability of FGH96 superalloy powder was investigated by field emission scanning electron microscopy (FE-SEM), laser particle size analyzer (LPSA) and X-ray photoelectron spectroscopy (XPS). The results showed that the powder flowability basically presented a decreasing trend as the median diameter decreased. The Hall velocity of the five median diameter powders (50=203.9 μm, 106.3 μm, 83.2 μm, 73.8 μm, 19.9 μm) was 27.18 s/50g, 23.25 s/50g, 23.86 s/50g, 23.42 s/50g and none, respectively. The surface oxides/ hydroxide/nitride of the five median diameter powders were mostly the same, mainly including Al2O3, Cr2O3, MoO3, Nb2O5, Ni (OH)2, TiO2 and TiN. The median diameter 50, shape factors (circularity, aspect ratio, roundness, solidity) and fractal dimension were selected to quantitatively characterize particle size and shape. For the same fluctuation value of powder flowability, the roundness and solidity showed lower sensitivity. Compared with the two shape factors, the sensitivity of circularity and aspect ratio was at an intermediate level, while the median diameter and fractal dimension displayed higher sensitivity. The median diameter and fractal dimension can be used to characterize the principal variation of flowability. The circularity and aspect ratio can be utilized to characterize the variation of flowability supplementally.

Sign in / Sign up

Export Citation Format

Share Document