this article addresses the interplay between heat of hydration and physico-mechanical properties of calcium sulfate hemi-hydrate in the presence of retarding additives such as citric and malic acids and sodium citrate. the heat of hydration was measured using a semi-isothermal calorimeter. results proved that citric and malic acids had superior impact on hydration and mechanical properties. whi...

Due-dates are often determined during sales negotiations between customers and the sales team of the firm. In the preliminary (pre-sale) stage, the customer provides a time interval (due-window) of his preferred due-dates. This interval reflects acceptable leadtimes, which are functions of the customer resource constraints (e.g. storage or personnel limitations). If the due-dates are assigned e...

objective: previous studies have demonstrated that dental stone casts can be disinfected by replacing 10v% of required water with 5.25% sodium hypochlorite solution. this comparative study evaluated physical properties of dental stone models produced by replacing distilled water with sodium hypochlorite.   methods: in this in-vitro experimental study, a total of 45 dental stone models were prod...

Students of social movements have long struggled with the question how relatively abstract political opportunities, such as elite divisions, affect unorganized activists without much knowledge of politics. We argue that the relationship between institutional opportunities and decisions to mobilize may take the form of trickle-down politics. In this view activists are affected by political oppor...

introduction: scatter radiation is one of the major sources of error in nuclear medicine data processing. different methods of scatter correction have been introduced in order to improve the quality of data. however the best method is to avoid recording of scatter photons in acquisition. the only difference between scattered and non-scattered photons is the energy. pulse height analyzer is the ...

introduction: the aim of the present study was to evaluate the effect of different mixing techniques (conventional, amalgamator and ultrasonic mixing) on the physical properties the working time (wt), setting time (st), dimensional changes (dc) and film thickness (ft)] of calcium-enriched mixture (cem) cement and mineral trioxide aggregate (mta). methods and materials: the mentioned physical pr...

optimal attributes are useful in interpretation of seismic data. two proposed methods are presented in this paper for finding optimal attributes. regularized discriminate analysis(rda) is based on 2 parameters ë, ? which called regularization parameter. the other method is principal component analysi s(pca).in this paper gas chimney detection is defined as the subject of study for ranking relev...