Statistical Models for Predicting the Optimum Gypsum Content in Cement Mortar

One of the most important problems in concrete industry in Iraq is deterioration due to internal sulfate attack that causes damage of concrete and hence reduces its compressive strength, increases its expansion and may be lead to its cracking and destruction. Linear regression analysis is used to predict the optimum SO3 content (O.G.C) on the basis of cement chemical composition, Blaine fineness and age. Three models are presented, the first one is an early age model (less than or equal to 7- days). Then a late age (greater than 7-days) model was developed based on the predicted optimum SO3 content of early age and late age. The third model was an all ages model and it is a general model specially for OPC. The important results obtained are the positive effect of C3S, C3A and C4AF on optimum SO3 content in cement mortar. The effect of C3A on optimum SO3 content is about twice that of C4AF. The study also showed a trend of positive and important effect of the fineness of cement

Statistical Model for Predicting the Optimum Gypsum Content in Concrete

The problem of internal sulfate attack in concrete is widespread in Iraq and neighboring countries.This is because of the high sulfate content usually present in sand and gravel used in it. In the present study the total effective sulfate in concrete was used to calculate the optimum SO3 content. Regression models were developed based on linear regression analysis to predict the optimum SO3 content usually referred as (O.G.C) in concrete. The data is separated to 155 for the development of the models and 37 for checking the models. Eight models were built for 28-days age. Then a late age (greater than 28-days) model was developed based on the predicted optimum SO3 content of 28-days and late age. Eight developed models were built for all ages. The important results obtained from the developed models are the positive effect of C3S, C3A and C4AF on optimum SO3 content. The effect of C3A on optimum SO3 content is about twice that of C4AF. The study also showed a trend of positive and important effect of the fineness of cement except in some models and this is due to statistical overla

Evaluation of functional SiO2 nanoparticles toxicity by a 3D culture model

International audienc

The financial stress spillover: Evidence from selected Asian countries

The objective of the study is to analyze financial stress spillover among selected Asian countries, namely, China, Pakistan, Sri Lanka, Malaysia and India for the period from Jan 2001 to Dec 2009. The financial stress is measured by Financial Stress Index (FSI), a specially designed comprehensive measure of financial stress. The methodology of Yimlam 2012 is adopted for analyzing dynamics of variance decomposition among countries using FSI for the selected countries. The results of the study confirm that China and Pakistan are the largest transmitters of spillover towards other selected countries. Also the net spillover of China and Pakistan indicated to be positive whereas all other countries show up negative net spillovers. The economic and geographic linkages are suggested to be responsible for influencing magnitude of spillover among selected countries. Finally, the response of each country to shocks in other countries is found to be positive