The densities and seismic velocities of rocks are relatively weak functions of temperature, pressure and composition unless these are accompanied by a drastic change in mineralogy. The physical properties of a rock depend on the proportions and compositions of the various phases or minerals-the mineralogy. These, in turn, depend on temperature, pressure and composition. In general, one cannot a...

in this work, the precipitation and re-dissolution of asphaltenes were studied for an iranian relatively heavy crude oil. a series of experiments were designed and carried out to quantitatively examine the reversibility of asphaltenes precipitation upon the change in the solvent concentration along with the temperature. n-heptane was used as the precipitant, and a temperature range of 30 to 70°...

We have prepared and analyzed five different compositions of GexAsySe1−x−y glasses that have the same mean coordination number MCN of 2.5 in order to understand whether MCN or chemical composition has the dominant effect on the physical properties of the glass. Density measurements showed a maximum for the chemically stoichiometric Ge12.5As25Se62.5 sample and suggested that some rearrangement o...

Decomposing the Composition Effect This paper proposes a decomposition of the composition effect, i.e. the part of the observed between-group difference in the distribution of some economic outcome that can be explained by differences in the distribution of covariates. Our decomposition contains three types of components: (i) the “direct contributions” of each covariate due to between-group dif...

in this work, a tracer study on pore initiation in anodic alumina in oxalic acid was performed. effects of some experimental parameters such as applied electrical potential, electrolyte composition and heat pretreatment were evaluated. electrochemical and morphological experiments were performed using potentiostatic anodizing and scanning electron microscopy (sem) techniques, respectively. effe...

A person's ability to translate a mathematical problem into symbols is an increasingly important skill as computational devices play an increasing role in academia and the workplace. Thus it is important to better understand this "symbolization" skill and how it develops. We are working toward a model of the acquisition of skill at symbolizing and scaffolding strategies for assisting that acqui...

purpose the aim of this study was to determine the effect of ramadan fasting on body composition, calorie intake and physical performance in young female athletes undertaking training sessions during ramadan. methods twelve voluntary female athletes (15-27 years old) were assigned to the research. a prospective study was conducted to investigate the athletes on four different occasions: one wee...