Liquid water is pushed through flow channels of fuel cells, where one surface is a porous carbon electrode made up of carbon fibers. Water drops grow on the fibrous carbon surface in the gas flow channel. The drops adhere to the superficial fiber surfaces but exhibit little penetration into the voids between the fibers. The fibrous surfaces are hydrophobic, but there is a substantial threshold ...

The effects of the removal of 18-MEA on the dynamic contact angle (advancing contact angle and receding contact angle) and friction force (friction force microscopy (FFM)) were examined in the present study. Chemically untreated hair tresses formed more finely ordered bundles, with the fibers aligned more parallel to each other, in the wet state, and lying flat and aligned parallel to each othe...

this study was conducted to investigate some moisture-dependent engineering properties of russian olive fruit including fruit dimensions, one thousand seed mass, surface area, sphericity, bulk and true density, angle of sliding and static friction coefficient against different surfaces. the physical properties of russian olive fruit were evaluated as a function of moisture content in the range ...

determination of physical properties of municipal waste compost is necessary to obtain the parameters related to designing and constructing a suitable pelleting machine for producing compost pellets. the purpose of this study is determining some physical properties such as; bulk density, coefficient of friction, porosity, angle of repose for compost and density and expansion for compost pellets...

compared to quartz sand, the shear behavior of carbonate sand differs in  appearance, origin, and kind. carbonate sand is found mainly in the northern coast of the persian gulf and the oman sea. in this research, a comparison is made between the shear behavior of carbonate sand retrieved from the eastern region of the chabahar port, located north of the oman sea, and quartz sand obtained from f...

In recent years, geotechnical engineers have paid much attention on reliability-based design. The probability density functions (PDFs) of the uncertain soil parameters are required for the reliability-based design. Once these PDFs are obtained, reliability analysis can be conducted, and reliability-based design can be achieved. Among the soil parameters, soil strengths play important roles in g...

We investigate the effect of nanoscale variations in the surface roughness of individual particles on macroscale granular flow characteristics. Experiments were conducted in circular rotating tumblers with smooth and rough 2 and 3 mm steel particles. The smooth beads had a rms surface roughness of approximately 30 to 60 nm; rough beads had a surface roughness of approximately 240 to 350 nm. The...

The discrete element method (DEM) has been used as a popular simulation method in order to verify the designs by visualizing how materials flow through complex equipment geometries.  Although DEM simulation is a powerful design tool, finding a DEM model that includes all real material properties is not computationally feasible.  In order to obtain more realistic results, particle energy loss du...

metal forming processes, compared with machining ones, reduce production steps and increasemanufacturing speed in addition to saving raw material. in this paper, forming process of column ofa steering mechanism is investigated by finite element analyses and experimental tests; andoptimum die design parameters are found. forming process parameters including die opening angle,bearing length, clea...

Direct tire-road contact friction estimation is essential for future autonomous cars and active safety systems. Friction estimation methods have been proposed earlier for driving conditions in the presence of a slip angle or slip ratio. However, the estimation of the friction from a freely-rolling tire is still an unsolved topic. Knowing the existing friction potential would be beneficial since...