The high carbon contents and low toxicity levels of chars from coal and pine gasification provide an incentive to consider their use as precursors of porous carbons obtained by chemical activation with K2CO3. Given the chars characteristics, previous demineralization and thermal treatments were made, but no improvement on the solids properties was observed. The highest porosity development was ...

Growth experiments have been carried out to characterize the occurrence and development of porosity in Bridgman and flux grown Al-Pd-Mn icosahedral quasicrystals. The porosity level has been observed to fluctuate between values of 0.0 and 3.75 percent along the length of Bridgman single crystals implying that the development of porosity is affected by the local growth conditions. Experiments we...

the kinetic of photo oxidative decolorization of c.i. acid yellow 23 (ay23) was investigated in uv/ process. the semi-logarithmic of the concentrations of ay23 versus irradiation time were linear, suggesting pseudo-first order reaction. a simple kinetic model is proposed which confirms pseudo- first order reaction. the results indicate that the apparent reaction rate constant is a function of l...

We present a pseudo-random bit generator expanding a uniformly random bitstring r of length k/2, where k is the security parameter, into a pseudo-random bit-string of length 2k − log(k) using one modular exponentiation. In contrast to all previous high expansion-rate pseudo-random bit generators, no hashing is necessary. The security of the generator is proved relative to Paillier’s composite d...

Water management in gas diffusion layer (GDL) and micro porous layer (MPL) poses a great impact on performance of proton exchange membrane fuel cells (PEMFCs). And enhancement of the performance of fuel cells requires an appropriate water balance between the conservation of membrane humidity and the discharge of excess water produced in the cell. The Lattice Boltzmann method (LBM) can enable mo...

the goal of this laboratory study is to investigate the effect of pore shapes on seismic wave velocities in carbonate rocks under reservoir conditions. in this research, 41 core plugs of carbonate rocks from oil fields of the southwest of iran were prepared. the compressional and shear wave velocities were measured in both dry and brine saturated samples under several pressures especially reser...

In industry, the porosity of petrochemical reservoirs is measured frequently by coring and is an important property when trying to determine if a site is appropriate for drilling. Porosity can also be used in waste water treatment in order to determine if a material is ideal for water purification in industrial or residential applications. The purpose of this experiment was to simulate a oil re...

The so-called pseudosquares can be employed in very powerful machinery for the primality testing of integers N . In fact, assuming reasonable heuristics (which have been confirmed for numbers to 2) they can be used to provide a deterministic primality test in time O(log N), which some believe to be best possible. In the 1980s D.H. Lehmer posed a question tantamount to whether this could be exte...