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Joanna Brzeska Aleksandra Heimowska Henryk Janeczek Marek Kowalczuk Maria Rutkowska 《Journal of Polymers and the Environment》2014,22(2):176-182
The aliphatic polyurethanes based on atactic poly[(R,S)-3-hydroxybutyrate] (a-PHB) and commercial oligomerols: poly(ε-caprolactone)diol and polyoxytetramethylenediol were investigated. a-PHB was obtained by anionic ring-opening polymerization of (R,S)-β-butyrolactone. The 4,4′-methylenedicyclohexyl diisocyanate and 1,4-butanediol were used as contributors of hard segments. The aim of the study was to determine the influence of synthetic, atactic a-PHB in soft segments of polyurethanes on their degradability in simulated body fluids (SBF) and Ringer solution. The incubation of polymer samples in both degradative solutions was carried out for 36 weeks. It was concluded that the presence of a-PHB in polyurethane structure accelerated their degradation in SBF and in Ringer solution and, protected the calcification process. 相似文献
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This paper describes the effect of the modification of polyurethane system with palm oil-based polyol on the cell structure and physical?Cmechanical properties of polyurethane foams. Flexible polyurethane foams were prepared by substituting a part of petrochemical polyether-polyol with the palm oil polyol. Selected physical?Cmechanical properties of these foams were examined and compared to the properties of reference foam. The properties such as apparent density, tensile strength, elongation at break, resilience, compressive stress and thermal stability were analyzed. It was found that the modifications of polyurethane formulation with palm oil polyol allow to improve selected properties of final products. 相似文献
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As Poland has signed and ratified the Framework Convention on Climate Change (FCCC), proper methodology for modeling the response of the economic system to greenhouse gas (GHG) abatement measures should be developed. The scheme of the Polish Country Study modeling system as well as the modeling algorithm for creating GHG abatement scenarios at the country level are presented. The mechanism of encouraging GHG emission reduction by policy measures is considered. The problem is discussed both from micro- and macroeconomic perspectives. Analysis of externalities was found to be an important element of the Country Study.
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The first detectable activities of radioiodine (131)I, and radiocaesium (134)Cs and (137)Cs in the air over Central Poland were measured in dust samples collected by the ASS-500 station in the period of 21(st) to 24(th) of March, 2011. However, the highest activity of both fission products, (131)I and (137)Cs: 8.3 mBq m(-3) and 0.75 mBq m(-3), respectively, were obtained in the samples collected on 30(th) March, i.e.~18 days after the beginning of the fission products' discharge from the damaged units of the Fukushima Daiichi Nuclear Power Plant. The simultaneously determined corrected aerosol residence time for the same samples by (210)Pb/(210)Bi and (210)Pb/(210)Po methods was equal to 10 days. Additionally, on the basis of the activity ratio of two other natural cosmogenic radionuclides, (7)Be and (22)Na in these aerosol samples, it was possible to estimate the aerosol residence time at ~150 days for the solid particles coming from the stratospheric fallout. These data, as well as the differences in the activity size distribution of (7)Be and (131)I in the air particulate matter, show, in contrast to the Chernobyl discharge, a negligible input of stratospheric transport of Fukushima-released fission products. 相似文献
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Michael K Stenstrom Diego Rosso Henryk Melcer Ron Appleton Victor Occiano Alan Langworthy Pete Wong 《Water environment research》2008,80(7):663-671
The City of San Diego, California, evaluated the performance capabilities of biological aerated filters (BAFs) at the Point Loma Wastewater Treatment Plant. The City conducted a 1-year pilot-plant evaluation of BAF technology supplied by two BAF manufacturers. This paper reports on the first independent oxygen-transfer test of BAFs at full depth using the offgas method. The tests showed process-water oxygen-transfer efficiencies of 1.6 to 5.8%/m (0.5 to 1.8%/ft) and 3.9 to 7.9%/m (1.2 to 2.4%/ft) for the two different pilot plants, at their nominal design conditions. Mass balances using chemical oxygen demand and dissolved organic carbon corroborated the transfer rates. Rates are higher than expected from fine-pore diffusers for similar process conditions and depths and clean-water conditions for the same column and are mostly attributed to extended bubble retention time resulting from interactions with the media and biofilm. 相似文献
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Bury Stanisław Zając Bartłomiej Okarma Henryk Kolanek Aleksandra 《Environmental science and pollution research international》2022,29(6):8334-8340
Environmental Science and Pollution Research - Depletion of free-living populations is often associated with changes in fitness-related traits, e.g., body size. Ongoing decrease in body size has... 相似文献
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An extremely potent mutagen, 3‐chloro‐4(dichloromethyl)‐5‐hydroxy‐2(5/f)‐furanone (MX) is commonly present in chlorinated drinking water. Due to its high mutagenic activity and according to WHO guidelines its concentration should be controlled in drinking waters. Determination of MX is difficult due to ppt levels at which the compound usually exists in drinking waters. Derivatization with 2‐propanol is presented as a method which significantly lowers GC/MS detection level of MX. Suitability of 2‐propylation for derivatization of other hydroxyfuranones is also shown. 相似文献
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Depleted uranium (DU) is a by-product of the 235U radionuclide enrichment processes for nuclear reactors or nuclear weapons. DU in the metallic form has high density and hardness as well as pyrophoric properties, which makes it superior to the classical tungsten armour-piercing munitions. Military use of DU has been recently a subject of considerable concern, not only to radioecologists but also public opinion in terms of possible health hazards arising from its radioactivity and chemical toxicity. In this review, the results of uranium content measurements in different environmental samples performed by authors in Kuwait after Gulf War are presented with discussion concerning possible environmental and health effects for the local population. It was found that uranium concentration in the surface soil samples ranged from 0.3 to 2.5 microg g(-1) with an average value of 1.1 microg g(-1), much lower than world average value of 2.8 microg g(-1). The solid fallout samples showed similar concentrations varied from 0.3 to 1.7 microg g(-1) (average 1.47 microg g(-1)). Only the average concentration of U in solid particulate matter in surface air equal to 0.24 ng g(-1) was higher than the usually observed values of approximately 0.1 ng g(-1) but it was caused by the high dust concentration in the air in that region. Calculated on the basis of these measurements, the exposure to uranium for the Kuwait and southern Iraq population does not differ from the world average estimation. Therefore, the widely spread information in newspapers and Internet (see for example: [CADU NEWS, 2003. http://www.cadu.org.uk/news/index.htm (3-13)]) concerning dramatic health deterioration for Iraqi citizens should not be linked directly with their exposure to DU after the Gulf War. 相似文献