scholarly journals External Hard Particle Size Effect on Changes in Frictional Performance and Grit Embedment during Drag and Stop Mode Braking

2014 ◽  
Vol 66 (3) ◽  
Author(s):  
M. K. Abdul Hamid ◽  
A. R. Abu Bakar ◽  
G. W. Stachowiak
Keyword(s):  
Particle Size ◽  
Wear Debris ◽  
Particle Size Effect ◽  
Silica Sand ◽  
Brake Disc ◽  
Hard Particle ◽  
Hard Particles ◽  
Effective Contact ◽  
Frictional Performance ◽  
Friction Performance

The effects of silica sand of 50-180 µm, 180-355 µm and 355-500 µm on friction performance and grit embedment at brake disc and pad interface was investigated. Results showed that present of external hard particles caused higher friction coefficient due to higher number of smaller particles involved in mixing and changing the effective contact, while good friction stability was attributed to smaller grit particles and compacted wear debris. Grit embedment was greatly dependent on presence of compacted wear debris as most grits were embedded into compacted wear debris with embedment of 0.8% was observed for 50-180 µm, 2% for 180-355 µm and 3% for 355-500 µm.

The Effects of Grit Particle Size on Frictional Characteristics of Automotive Braking System

2011 ◽  
Vol 189-193 ◽  
pp. 3511-3516
Author(s):  
Mohd Kameil Abdul Hamid ◽  
Gwidon W. Stachowiak
Keyword(s):  
Particle Size ◽  
Friction Coefficient ◽  
Contact Area ◽  
Wear Debris ◽  
Silica Sand ◽  
Test Rig ◽  
Braking System ◽  
Hard Particles ◽  
Effective Contact

The effect of grit particle size on frictional characteristics was investigated using a vertically oriented brake test rig. Silica sand of grit sizes 50-180 µm, 180-355 µm and 355-500 µm were used in drag mode application. Results showed that the presence of hard particles from environment can influence the friction response significantly. Basically, once the hard particles enter the gap, the value and amplitude of friction coefficient tend to decrease. However, slight increase in friction with smaller particles was recorded due to more hard particles involved in mixing and changing the effective contact area. Better friction stability was related to the presence of smaller grit particles and compacted wear debris to form frictional film on the braking interface.

Effects of External Hard Particles on Brake Friction Characteristics During Hard Braking

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
M. K. Abdul Hamid ◽  
G. W. Stachowiak
Keyword(s):  
Standard Deviation ◽  
Friction Coefficient ◽  
Contact Area ◽  
Oscillation Amplitude ◽  
Stopping Time ◽  
Hard Particle ◽  
Friction Coefficients ◽  
Hard Particles ◽  
Effective Contact ◽  
Friction Oscillation

The effects of external hard particles on the friction coefficients and its oscillation amplitudes during hard braking were investigated. Silica sands of the size between 180 to 355 μm were used during the experiments. The results were compared to the results obtained without the grit particles present in order to determine the change in friction coefficient and the fluctuation of frictional oscillation amplitude. Different sliding speeds were applied and external hard particle of different size is found to significantly affect the friction coefficient and standard deviation of friction oscillation amplitude values. The friction coefficients increase with hard particle due to the rapid changes of the effective contact area and the abrasion mode. Some embedded particles operating in two body abrasion mode help to increase the disc surface roughness and influence the stopping time of the disc. The standard deviation values of friction oscillation amplitude however were stable due to more wear debris produced and get compacted to form friction films assisting friction and they tend to reduce at medium speeds because many contact plateaus and effective contact area started to stabilize.

Effects of External Hard Particles on Brake Friction Characteristics During Hard Braking

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
M. K. Abdul Hamid ◽  
G. W. Stachowiak
Keyword(s):  
Standard Deviation ◽  
Friction Coefficient ◽  
Contact Area ◽  
Oscillation Amplitude ◽  
Stopping Time ◽  
Hard Particle ◽  
Friction Coefficients ◽  
Hard Particles ◽  
Effective Contact ◽  
Friction Oscillation

The effects of external hard particles on the friction coefficients and its oscillation amplitudes during hard braking were investigated. Silica sands of the size between 180 to 355 μm were used during the experiments. The results were compared to the results obtained without the grit particles present in order to determine the change in friction coefficient and the fluctuation of frictional oscillation amplitude. Different sliding speeds were applied and external hard particle of different size is found to significantly affect the friction coefficient and standard deviation of friction oscillation amplitude values. The friction coefficients increase with hard particle due to the rapid changes of the effective contact area and the abrasion mode. Some embedded particles operating in two body abrasion mode help to increase the disc surface roughness and influence the stopping time of the disc. The standard deviation values of friction oscillation amplitude however were stable due to more wear debris produced and get compacted to form friction films assisting friction and they tend to reduce at medium speeds because many contact plateaus and effective contact area started to stabilize.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

scholarly journals Particle Size Effect of Lanthanum-Modified Bismuth Titanate Ceramics on Ferroelectric Effect for Energy Harvesting

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Sangmo Kim ◽  
Thi My Huyen Nguyen ◽  
Rui He ◽  
Chung Wung Bark
Keyword(s):  
Particle Size ◽  
Energy Harvesting ◽  
High Speed ◽  
High Performance ◽  
Bismuth Titanate ◽  
Vinylidene Fluoride ◽  
Piezoelectric Materials ◽  
Renewable Energy Sources ◽  
Particle Size Effect ◽  
Ferroelectric Materials

AbstractPiezoelectric nanogenerators (PNGs) have been studied as renewable energy sources. PNGs consisting of organic piezoelectric materials such as poly(vinylidene fluoride) (PVDF) containing oxide complex powder have attracted much attention for their stretchable and high-performance energy conversion. In this study, we prepared a PNG combined with PVDF and lanthanum-modified bismuth titanate (Bi4−XLaXTi3O12, BLT) ceramics as representative ferroelectric materials. The inserted BLT powder was treated by high-speed ball milling and its particle size reduced to the nanoscale. We also investigated the effect of particle size on the energy-harvesting performance of PNG without polling. As a result, nano-sized powder has a much larger surface area than micro-sized powder and is uniformly distributed inside the PNG. Moreover, nano-sized powder-mixed PNG generated higher power energy (> 4 times) than the PNG inserted micro-sized powder.

scholarly journals Green Light Emission ofZnxCd1-xSeNanocrystals Synthesized by One-Pot Method

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shu-Ru Chung ◽  
Kuan-Wen Wang ◽  
Hong-Shuo Chen
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Light Emission ◽  
Green Light ◽  
Particle Size Effect ◽  
Partial Replacement ◽  
Face Centered Cubic ◽  
One Pot ◽  
Zn Content ◽  
High Emission

We present a facile one-pot synthesis to prepare ternaryZnxCd1-xSe(x= 0.2, 0.5, 0.8, and 1) nanocrystals (NCs) with high emission quantum yield (QY, 45~89%). The effect of Zn content (x) ofZnxCd1-xSeNCs on their physical properties is investigated. The NCs have a particle size of 3.2 nm and face centered cubic structure. However, the actual compositions of the NCs are Zn0.03Cd0.97Se, Zn0.11Cd0.89Se, and Zn0.38Cd0.62Se when Zn content is 0.2, 0.5, and 0.8, respectively. In terms of the optical properties, the emission wavelength shifts from 512 to 545 nm with increasing Zn content from 0 to 0.8 while the QY changes from 89 to 45, respectively. Partial replacement of Cd by Zn is beneficial to improve the QY of Zn0.2and Zn0.5NCs. The optical properties of ternary NCs are affected by compositional effect rather than particle size effect.

Particle-size effect on the compressibility of nanocrystalline alumina

2002 ◽  
Vol 66 (14) ◽  
Author(s):  
B. Chen ◽  
D. Penwell ◽  
L. R. Benedetti ◽  
R. Jeanloz ◽  
M. B. Kruger
Keyword(s):  
Particle Size ◽  
Size Effect ◽  
Particle Size Effect ◽  
Nanocrystalline Alumina

Au, @ZrO2 yolk–shell catalysts for CO oxidation: Study of particle size effect by ex-post size control of Au cores

2012 ◽  
Vol 289 ◽  
pp. 100-104 ◽  
Author(s):  
Robert Güttel ◽  
Michael Paul ◽  
Carolina Galeano ◽  
Ferdi Schüth
Keyword(s):  
Particle Size ◽  
Size Effect ◽  
Co Oxidation ◽  
Size Control ◽  
Particle Size Effect ◽  
Oxidation Study ◽  
Ex Post

Particle size effects in the selective hydrogenation of cinnamaldehyde over supported palladium catalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75541-75551 ◽  
Author(s):  
Feng Jiang ◽  
Jian Cai ◽  
Bing Liu ◽  
Yuebing Xu ◽  
Xiaohao Liu
Keyword(s):  
Particle Size ◽  
Size Effect ◽  
Selective Hydrogenation ◽  
Size Effects ◽  
Palladium Catalysts ◽  
Particle Size Effect ◽  
Particle Size Effects ◽  
Supported Palladium Catalysts ◽  
Supported Palladium ◽  
Palladium Particles

Palladium particles of different sizes obtained directly and indirectly by various methods were studied to clarify the particle size effect in the selective hydrogenation of cinnamaldehyde (CAL).

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