the soil water retention curve (swrc) is a basic characteristic of the determination of soil hydraulic properties, including unsaturated hydraulic conductivity. measurement of this curve is essential to research, thus scientists have focused on indirect methods such as pedotransfer functions and empirical relationships to estimate swrc easily. since there is a close relationship between swrc an...

physicochemical and mechanical properties of wheat grains can have a great impact on the quality of the final products (bread). therefore, correct selection of wheat cultivar for specific applications seems to be crucial. in this study, the differences in the physicochemical and mechanical properties (under compression and impact loadings) of ten iranian wheat cultivars (azar2, alamut, bam, bah...

laboratory bioassays were carried out to study the insecticidal efficacy of two iranian diatomaceous earths (des) and silicosecâ® formulation against sitophilus granarius (l.). four different particle sizes of des were applied at five concentrations. the mortality was counted 2, 5 and 7 days after exposure. the experiment was carried out at 27 â± 1â°c and 55 â± 5% relative humidity in continuou...

tricalcium phosphate as hydroxyapatite is used as a suspension stabilizer in styrene polymerization process. particle size of tcp plays an essential role in the particles’ size distribution and geometrical form of polystyrene products. as the particle size of tcp is reduced, there will be much better chance to engulf the styrene particles. the higher the number of tcp particles surrounding each...

The presence of N-phenyl-p-phenylenediamine (PPDA: a dimer of aniline) during microwave (MW) irradiation can significantly improve Pt-loading on the XC72 carbon matrix as a catalyst support of proton exchange membrane fuel cells (PEMFCs). PPDA is converted to an emeraldine base state during MW-assisted redox reaction, which is characterized by both FTIR and Raman spectra. The increased degree o...

Rh/SiO(2) model catalyst surfaces are prepared under ultra-high vacuum conditions and examined in situ using scanning tunneling microscope and CO infrared reflection absorption techniques, to quantify the number and kinds of active Rh surface sites available for kinetic reaction (CO oxidation) as a function of Rh particle size. The results are compared against CO desorption measurements and ele...

Heterogeneous catalysts have been pivotal to the development of the modern chemical industry and are essential for catalysing many industrial reactions. However, reaction rates are different for every individual catalyst particle and depend upon each particle's morphology and size, crystal structure and composition. Measuring the rates of reaction on single nanocrystals will enable the role of ...

During metal-catalyzed growth of tapered silicon nanowires, or silicon nanocones (SiNCs), Au-Si eutectic particles are seen to undergo significant and reproducible reductions in their diameters. The reductions are accompanied by the transfer of eutectic droplet mass to adjacent, initially metal catalyst-free substrates, producing secondary nucleation and growth of SiNCs. Remarkably, the catalys...

A careful comparison was performed between Cu and Fe as catalysts for the growth of horizontally aligned ultralong single-walled carbon nanotube (SWNT) arrays on SiOx/Si substrates, and the mechanism of the difference was discussed. Cleaner and straighter SWNTs with smaller diameters and narrower size distribution were obtained using Cu as catalyst. It was also found that the SWNTs always grew ...

Solvent-free technique was employed in this work in order to assess the influence of the calcination temperature on the activity of Al-promoted sulfated zirconia. The catalyst was analyzed by XRD and IR-spectrum method, and catalytic activity was examined by esterification reaction of oleic acid. XRD analysis revealed that a decline in the percentage of tetragonal phases of zirconia was observe...