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121.
Feasibility of a waste material, flyash, as a material for purification of wastewater containing Lissamine Red has been studied. Effects of time and concentration, temperature and pH on the removal of the dye have been studied. Lower concentrations favour the uptake of dye from water and the maximum removal was observed at a dye concentration of 20 mgL m 1 , 30°C, pH of 7 and adsorbent particle size of 53 µm. Dynamics of the uptake was studied using Lagergren's equation. The mass transfer coefficient was found to be 0.05 cmmin m 1 at a concentration of 20 mgL m 1 , 30°C and 53 µm particle size.  相似文献   
122.
Toxic metals like lead, manganese, copper and cadmium damage neurons and deregulate neurotransmitters like serotonin and dopamine (which are essential to normal impulse control and learning). Earlier studies show that — controlling for socio‐economic and demographic factors — environmental pollution with lead is a highly significant risk factor in predicting higher rates of crime, attention deficit disorder or hyperactivity, and learning disabilities. Exposure and uptake of lead has been associated with industrial pollution, leaded paint and plumbing systems in old housing, lead residues in soil, dietary habits (such as shortages of calcium and iron), and demographic factors (such as poverty, stress, and minority ethnicity). We report here on an additional “risk co‐factor” making lead and other toxic metals in the environment more dangerous to local residents: the use of silicofluorides as agents in water treatment. The two chemicals in question — fluosilicic acid and sodium silicofluoride — are toxins that, despite claims to the contrary, do not dissociate completely and change water chemistry when used under normal water treatment practices. As a result, water treatment with siliconfluorides apparently functions to increase the cellular uptake of lead. Data from lead screening of over 280,000 children in Massachusetts indicates that silicofluoride usage is associated with significant increases in average lead in children's blood as well as percentage of children with blood lead in excess of 10μg/dL. Consistent with the hypothesized role of silicofluorides as enhancing uptake of lead whatever the source of exposure, children are especially at risk for higher blood lead in those communities with more old housing or lead in excess of 15 ppb in first draw water samples where silicofluorides are also in use. Preliminary findings from county‐level data in Georgia confirm that silicofluoride usage is associated with higher levels of lead in children's blood. In both Massachusetts and Georgia, moreover, behaviors associated with lead nurotoxicity are more frequent in communities using silicofluorides than in comparable localities that do not use these chemicals. Because there has been insufficient animal or human testing of silicofluoride treated water, further study of the effect of silicofluorides is needed to clarify the extent to which these chemicals are risk co‐factors for lead uptake and the hazardous effects it produces.  相似文献   
123.
Examination of the changing composition of shopping centres in suburban Sydney between 1969 and 1998 suggests that retail restructuring is linked to lifestyle changes. The growth in the number of shops appears to have matched population growth in the 1990s, suggesting that the suburbanisation of retailing has stabilised. At the same time there has been increasing diversification in terms of the retail functions which are available and in terms of the places where these are available. These changes appear linked to a blurring of the distinction between shopping and leisure and to the use of shopping as a way of signifying identity.  相似文献   
124.
Large‐span reinforced concrete (RC) shells collapses that occurred in the last decade caused many death toll as well as significant losses to national economies. The most famous cases were the collapse of the aqua park cover in Moscow on February 2004 and the 2E terminal roof destruction at Charles de Gaulle Airport near Paris on May 2004. Following the publications of the appropriate commissions that have studied the reasons of these events, the influence of concrete creep and changes in the shell geometry on buckling of RC thin‐walled shells was not properly considered in the design. This study is focused on buckling of such shells, taking into account geometrical and physical nonlinear behaviour of compressed concrete. Other important reasons of concrete shells collapse are also analysed. The study is based on available experimental and theoretical investigations of ferro‐cement shells' models previously performed by the first author. The results of these investigations, obtained for small‐scale ferro‐cement models of thin‐walled shallow RC shells, are discussed. Behaviour of the tested models is compared with that of the above‐mentioned real shells and similar structures, which also collapsed. The critical buckling loads for the shells are obtained. It is shown that these loads are lower than the actual ones; thus, the shells buckling was unavoidable. To prevent brittle shell failure, they should be designed using other dominant failure modes that appear before the buckling. Possible failure schemes of real RC shells can be predicted using dominant failure modes obtained by laboratory testing of scaled models. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
125.
A continuous oxygen uptake meter or continuous respirometer was developed which produced a rapid and reliable response to systemic shocks. The respirometer basically is a 101. Plexiglas laboratory activated sludge unit with a variable volume air tight side car. The feed enters the completely mixed aeration basin and is pumped into the side car. The side car is the site of the oxygen uptake measurements as indicated by a continuously monitoring dissolved oxygen probe. The system was most sensitive to changes in influent concentrations when run at an F/M = 0.1. Response time for a change in DO of 0.1 ppm was less than 4 min. The continuous respirometer was tested employing both synthetic and raw industrial wastes.  相似文献   
126.
127.
Fibre Chemistry - Modification of polycaproamide by 1H,1H,13H-trihydroperfluorotridecan-1-ol immobilized on montmorillonite produced an F-containing polymer composite. The structure of the...  相似文献   
128.
Sofronova  E. D.  Lipin  V. A.  Sustavova  T. A. 《Fibre Chemistry》2022,53(5):342-345
Fibre Chemistry - Under modern conditions the creation of materials for sanitary hygiene and medical products based on cellulose is of paramount importance. Development and improvement in this area...  相似文献   
129.
Makarov  R. I.  Khorosheva  E. R. 《Glass and Ceramics》2022,78(9-10):350-352
Glass and Ceramics - Selective quality control of manufactured multilayer windshields was conducted. Deviations of curved products from a specified shape were brought to light. Linear regression...  相似文献   
130.
Glass and Ceramics - A catalyst was developed in the form of a composite based on a zeolite matrix modified with titanium nanoparticles based on zeolite raw materials from the Kulikovskoe deposit...  相似文献   
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