background and objectives: today, 24-hours work is an unavoidable component in several industries. night-work is an imperative situation for an important part of workforces. shift-working is called to work at hours out of usual day-work time (7:00 am to 6:00 pm). the present study was a cross sectional descriptive-analytic research, and was carried out in order to investigate sleepiness and cha...

The temperature of the transition to the polar state in ferroelectric composites, representing spherical ferroelectric inclusions embedded in a dielectric matrix, under a depolarizing field effect is investigated. This temperature is determined both in the absence and presence of screening effects of the depolarizing field of the bound charges of spontaneous polarization at the inclusions surfa...

We present a simple method for directly measuring the average dwell time of spin-polarized Rb atoms on coated Pyrex glass surfaces. The method relies on the light shift of the Zeeman resonances of spin-polarized Rb atoms pumped and probed by evanescent waves, and does not depend on the microscopic details of surface interactions. We use a cell whose length is adjustable between 70 and 500 micro...

leaching of molybdenite concentrate with hydrogen peroxide in sulfuric acid solution was investigated to determine the effects of reaction time, reaction temperature, h2o2 concentration, h2so4 concentration, pulp density and rotation speed on molybdenum extraction and molybdenite dissolution kinetics, using the taguchi method. from analysis of variance (anova) for molybdenum extraction, the mos...

injection molding is one of the most common processes which are used for manufacturing different plastic parts. this method includes 3 continuous steps: filling of the mold, cooling and driving the part out. a wide range of plastic and non-plastic materials can be used as raw material in this process. one of the most important advantages of this way of production is that it is very economic. in...

the antioxidant properties of ruta graveolens l. were evaluated by two different methods; free radical scavenging using dpph and inhibition of lipid peroxidation by the ferric thiocyanate method. the ic50 value of the methanol extract in dpph inhibition was 200.5 μg/ml which was acceptable in comparison with bht (41.8 μg/ml). in thiocyanate method, the plant extract demonstrated activity as muc...

nowadays the researches have indicated the fact that using synthetic antioxidants as food additives in edible oils can have adverse effects on human health. so preparing antioxidation resources for reduction of oxidation stress effects is important. the aim of this project was, representing a natural antioxidant source with frap test. the present study optimized the ultrasound assisted extracti...

We study the role of filler concentration and microphysics on rheology polydisperse flake-graphite particles suspended in Newtonian mineral oil. Under steady shear, our samples exhibit shear thinning, yielding behavior is observed for volume fractions [Formula: see text]. Time-temperature superposition was using an Arrhenius-type horizontal shift factor, giving a flow activation energy that dep...