The behaviour of flanged, and composite prestressed concrete beams under torsion and flexure

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Durability of self-compacting concrete containing pumice and zeolite against acid attack, carbonation and marine environment

International audienceDue to their fluidity and simplicity of use, self-compacting concretes (SCCs) have undeniable advantages. Since the study on the behavior of SCC containing pumice or zeolite with respect to aggressive media as acid attack and carbonation is very rare in literature, the purpose of this study is to focus on this subject. In this study, the influence of the partial substitution of 10% and 15% of Portland cement by pumice and zeolite admixtures on the fresh state, compressive strength of self-compacting concrete (SCC) is investigated. For durability, resistance to acid attack, carbonation and marine environment is studied. The results show different behaviors depending on the nature of the pozzolan. SCCs containing pumice exhibit a compressive strength at least equal to that of control concrete at early ages and higher than the ones of the control mix at long term ages. In contrast, SCC based on zeolite has a lower resistance compared to the control concrete due to the presence of a large porosity formed during the preparation of the mixture. This study shows and quantifies the positive effect of the partial substitution of Portland cement by 10% and 15% of pumice and 15% of zeolite on improving chemical resistance in acid attack. The carbonation study showed a lower resistance of SCCs containing pozzolan, this effect is more important for SCC with zeolite. Additional studies on the formulation and the properties at the fresh state of concrete containing zeolite in order to improve the mechanical strength will surely make it possible to obtain better performance and thus better profits from this natural pozzolan. © 2017 Elsevier Lt

A STUDY FOR REMOTE DETECTION OF INDUSTRIAL EFFLUENTS’ EFFECT ON RICE USING THERMAL IMAGES

Rice is one of the most important nutritious grains all over the world, so that only in some parts of Asia more than 300 million acres allocated for cultivating this product. Therefore, qualitative and quantitative management of this product is of great importance in commercial, political and financial viewpoints. Rice plant is very influenced by physical and chemical characteristics of irrigation water, due to its specific kind of planting method. Hence, chemically-polluted waters which received by plant can change in live plants and their products. Thus, a very high degree of treatment will be required if the effluent discharges to rice plants. Current waters receive a variety of land-based water pollutants ranging from industrial wastes to excess sediments. One of the most hazardous wastes are chemicals that are toxic. Some factories discharge their effluents directly into a water body. So, what would happen for rice plant or its product if this polluted water flow to paddies? Is there any remotely-based method to study for this effect? Are surface temperature distributions (thermal images) useful in this context? The first goal in this research is thus to investigate the effect of a simulated textile factory’s effluent sample on the rice product. The second goal is to investigate whether the polluted plant can be identified by means of thermal remote sensing or not. The results of this laboratory research have proven that the presence of industrial wastewater cause a decrease in plant’s product and its f-cover value, also some changes in radiant temperature

Methodological considerations in using the Network Scale up (NSU) for the estimation of risky behaviors of particular age-gender groups: An example in the case of intentional abortion

BackgroundNetwork Scale Up (NSU) is a promising tool for size estimation of sensitive issues. In this study we investigated the important methodological considerations to employ this method for estimating behaviors, such as abortion, which happens in a particular age-gender group.MethodsWe recruited 1250 males and 1250 females aged 18 to 50. Abortion rate was calculated through direct question and NSU methodology. The NSU was applied on three sub-samples (male, female and aggregate). Integrating replies to 25 reference groups, we estimated the network size (C) of respondents and its age-gender structure. To calculate the part of network that is subject to abortion, we compared two approaches: proportional and data based. The Visibility Factor (VF) was calculated through 222 females who had abortion. Direct estimate was considered as gold standard.ResultsUsing C's derived from proportional method, the Relative Bias (RB) in the male and female samples was 33% and 84%. Applying the data-based C's, the RB in the gender-specific and aggregate samples was 5% and 2%.ConclusionThe proportional method overestimates the prevalence. The data-based method to calculate the C is superior. The determination of the age-sex distribution of the network and the specific VF is essential

National population size estimation of illicit drug users through the network scale-up method in 2013 in Iran

Background For a better understanding of the current situation of drug use in Iran, we utilized the network scale-up approach to estimate the prevalence of illicit drug use in the entire country. Methods We implemented a self-administered, street-based questionnaire to 7535 passersby from the general public over 18 years of age by street based random walk quota sampling (based on gender, age and socio-economic status) from 31 provinces in Iran. The sample size in each province was approximately 400, ranging from 200 to 1000. In each province 75 of sample was recruited from the capital and the remaining 25 was recruited from one of the large cities of that province through stratified sampling. The questionnaire comprised questions on demographic information as well as questions to measure the total network size of participants as well as the network size in each of seven drug use groups including Opium, Shire (combination of Opium residue and pure opium), Crystal Methamphetamine, heroin/crack (which in Iranian context is a cocaine-free drug that mostly contains heroin, codeine, morphine and caffeine with or without other drugs), Hashish, Methamphetamine/LSD/ecstasy, and injecting drugs. The estimated size for each group was adjusted for transmission and barrier ratios. Results The most common type of illicit drug used was opium with the prevalence of 1500 per 100,000 population followed by shire (660), crystal methamphetamine (590), hashish (470), heroin/crack (350), methamphetamine, LSD and ecstasy (300) and injecting drugs (280). All types of substances were more common among men than women. The use of opium, shire and injecting drugs was more common in individuals over 30 whereas the use of stimulants and hashish was largest among individuals between 18 and 30 years of age. Conclusion It seems that younger individuals and women are more desired to use new synthetic drugs such as crystal methamphetamine. Extending the preventive programs especially in youth as like as scaling up harm reduction services would be the main priorities in prevention and control of substance use in Iran. Because of poor service coverage and high stigma in women, more targeted programs in this affected population are needed. © 2016 Elsevier B.V