Today, urbanised people spend most of their time in indoor environments, and the risk of exposure to toxic materials in an indoor environment is of great concern. This paper considers sources for the inhalation risk of aerosol sprays by measuring the particle size distributions of some of the most popular products that are commercially available in Bangladesh, and examines the degree of toxicity and the health risk via the respirability of the products. Results show that thoracic and respirable fractions of the suspended particulate matter are present in the tested samples and hence the spray products may pose a significant health risk. 相似文献
An efficient procedure for the regioselective synthesis of secondary alcohol alkoxylates from 2,2,4-trimethyl-1,3-pentanediol
(TMPD) is described. TMPD was reacted with propylene oxide followed by ethylene oxide in the presence of a catalytic amount
of alkali metal hydroxide to form secondary alcohol alkoxylates. Instead of a mixture of compounds resulting from the reaction
of TMPD and propylene oxide, the primary hydroxyl group of the TMPD reacted to form predominantly 2,2,4-trimethyl-3-hydroxypentylpropoxylate
as the major product. On further ethoxylation the less hindered secondary hydroxyl group of the 2,2,4-trimethyl-3-hydroxypentylpropoxylate
reacted predominantly. 13C NMR indicated that the secondary hydroxyl group (96.2 mol%) of TMPD remained unreacted during alkoxylation. 相似文献
The potential of grid-connected solar PV system in Bangladesh was estimated utilizing GeoSpatial toolkit, NASA SSE solar radiation data and HOMER optimization software. Financial viability of solar photovoltaic as an electricity generation source for Bangladesh was also assessed utilizing a proposed 1-MW grid-connected solar PV system using RETScreen simulation software for 14 widespread locations in Bangladesh. The technical potential of gird-connected solar PV in Bangladesh was calculated as about 50174 MW. The annual electricity generation of the proposed system varied depending on the location between 1653 MWh and 1854 MWh, with a mean value of 1729 MWh. Several different economic and financial indicators were calculated, such as the internal rate of return, net present value, benefit-cost ratio, cost of energy production and simple payback. All indicators – for all sites – showed favorable condition for development of the proposed solar PV system in Bangladesh. The results also showed that a minimum of 1423 tons of greenhouse gas emissions can be avoided annually utilizing the proposed system at any part of the country. 相似文献
The conventional electricity grids, which are supposed to supply the electricity to the plug-in hybrid electric vehicles (PHEVs), need to adapt to overcome the problems of reliability, security, economics and environmental concerns. Accordingly, electric utilities in several countries are exploring the possibilities of implementing more robust interactive smart grids. This article analyses salient features of a smart grid in the Canadian perspective, and discusses PHEV and its role in the future smart grid. A simulation tool has been used to assess the impacts of charging of PHEV on the future electricity grid of Canada under different penetration rates. The article indicates the associated environmental benefits of PHEV. 相似文献
An attempt was made to print cotton fabric with pigments using a new thickening agent based on Aloe vera gel in combination with sodium alginate. The results were compared with the standard conventional printing recipe containing synthetic thickener, and a favourable effect of Aloe vera introduction was achieved. The results show that the properties of the printed fabric (sharpness, colour yield, overall fastness properties, softness, and water vapour transmission) are dependent on the percentage of Aloe vera gel in the thickener combination, the concentration of printing auxiliaries, and the curing conditions. Optimal printing properties were achieved by using a printing paste containing 80% Aloe vera/20% sodium alginate (700 g kg?1), pigment (50 g kg?1), binder (145 g kg?1), fixer (10 g kg?1), and ammonium sulfate (5 g kg?1), followed by drying at 85 °C for 5 min and curing at 150 °C for 3 min. The sample printed with the new recipe showed superior rubbing fastness and handle properties, with a slightly lower colour yield, when compared with the sample printed with synthetic thickener. Finally, economic issues arising from synthetic thickener substitution are highlighted. 相似文献
Transition to alternative energy is receiving serious attention globally and in this very way, biodiesel from inedible neem can be an alternative to conventional liquid fuels as it contains 30–45%?wt of oil. In this study, esterification and transesterification reaction of methanol and triglycerides at a molar ratio of 7:1 was done and maximum 96% by volume biodiesel was extracted. Physiochemical properties of neem biodiesel lies within ASTM standards and Fourier transform infrared spectroscopy analysis of neem biodiesel reveals the presence of strong esters and the alkane group. The maximum efficiencies were found to be 22.8% and 22.3%, whereas minimum brake specific fuel consumptions were observed to be 0.57 and 0.59?kg/kW-hr for diesel and B20, respectively. Moreover, B20 provides less emission of HC, COx and increase in NOx. Taking all into consideration, if at least 60% of the arid lands is utilised to cultivate neem trees then it will minimise the import of fossil fuel to an extent of 8.75%. 相似文献
Two green nanocomposites of Co3O4 decorated CTAB/bentonite (Co@CT/BE) and chitosan/bentonite (Co@CH/BE) were synthesized as enhanced and environmental photocatalysts and antibacterial agents. As photocatalysts, the products were applied in the effective oxidation of toxic methyl parathion pesticide (MP) in wastewater under a visible light source. The application of Co@CH/BE (0.02 g) resulted in the complete oxidation of MP (50 mg/L) after 40 min and complete mineralization after 60 min. while the complete oxidation and mineralization of MP (50 mg/L) by Co@CT/BE was recognized after 75 min and 100 min, respectively. The Co@CH/BE composite is of higher activity than Co@CT/BE and can cause complete oxidation for MP at high concentrations up to 100 mg/L after 75 min. The oxidation pathway was illustrated considering the existence of the hydroxyl radicals as the active oxidizing species and the identified secondary organic compounds during the oxidation tests. The detected intermediate converted into end products of CO2 and inorganic anions of SO4?2, NO3?, and PO4?3 at the final stages of the oxidation processes. As antibacterial agents, the two composites exhibit considerable inhabitation zones of about 20 mm against both the Gram-positive Staphylococcus aureus and Gram-negative bacterium Vibrio Sp. The synthetic Co@CH/BE showed the best antibacterial properties with 200 μg/mL as minimum inhibitory against Staphylococcus aureus.