tehran is located in a valley at the foot of the alborz mountains in northern iran (35 degrees latitude north). urban expansion in tehran resulted from a high rate of population growth and rural-urban migration combined with a strong tradition of centralization in the capital. airborne particulate of tehran's atmosphere was fractionated in a 6-stage high-volume cascade impactor. the first ...

background & aim: the artificial teeth are produced with same standards for all the ethnics and countries in the world. the purpose of this study was to establish a normative size distribution in a group of students and staffs of shahid beheshti university of medical sciences. methods & materials: 320 individuals participated in this descriptive study. a vernier caliper was used to measure the ...

background : this research provides an insight into exposure information and particle size distributions of bisphenol a (bpa), a common environmental hormone, at polycarbonate (pc) molding plants in southern taiwan. methods : the inhalable dust sampler as iom and the micro-orifice uniform deposition impactor (moudi) were used for samples collection to evaluate the level and particle size distri...

as a native fermented dairy drink, doogh is an important industrial product in iran. however, its characteristics have not been completely evaluated. this study evaluated the flow behavior, particle size distribution and stability of non-fat doogh as affected by the row material employed (fresh skim milk or skim milk powder) and the total solids (ts) content of the final drink. the viscosity of...

the design of cement slurry for horizontal wellbores is challenging as it must present very high quality cement slurry properties e.g. zero free water, less than 50 cc api fluid loss value, appropriate rheology and yield point for effective displacement, adequate compressive strength, which is critical for lightweight slurries, and finally stable cement column behind casing. the main objective ...

the benefits of using mineral admixtures as a partial replacement of portland cement (pc) are well established in the literature. economic and environmental advantages by reducing co2 emissions are well known. this paper examines the influence of intergrinding and separate grinding on the amount of energy consumption, blaine fineness and particle size distribution (psd) of blended cements, name...

gold nanoparticles were synthesized by chemical reduction of haucl4 inside the pores of a polycarbonate-based membrane followed by dissolving the membrane in dichloromethane and further sonication. sonication time as the main affecting factor on the nanoparticle size was investigated. the characterization by transmission electron microscopy showed the formation of gold nanoparticles with diamet...

The use of classical, or time-averaged, light scattering methods to characterize the size and size distribution of macromolecules in dilute solutions or particles in dilute dispersions is discussed. The necessary scattering relations are presented systematically, starting with three cases at infinite dilution: the scattering extrapolated to zero angle, the scattering at small angle, and the sca...

Abstract I seems to be widely believed that the Fourier and Laplace transforms are simply related to each other. Nothing could be further from the truth. The Fourier transform is the basis for the Hilbert vector-space expansion of signals. The Laplace transform is the basis of system functions, that are causal. The Fourier transform does not naturally include the step function, which must be sh...

quantum dots of cds with hexagonal phase were prepared at relatively low temperature (60 oc) and short time by micro-emulsion (o/w) under ultrasound. this study was focused on the particle size distribution and the growth kinetics. the particle size distribution obtained from the optical absorption edge. it was relatively symmetrical with sonication time. in addition, an agreement was observed ...