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991.
Estrogenic personal care products in a greywater reuse system. 总被引:1,自引:0,他引:1
H R Andersen M Lundsbye H V Wedel E Eriksson A Ledin 《Water science and technology》2007,56(12):45-49
The occurrence and fate of parabens in a greywater system was assessed. The potential for removal of residual paraben concentrations in effluent greywater with chlorine dioxide was also investigated. The influent to the greywater plant was characterised by considerable variation, with concentrations from below the detection limit to 40 microg/L and the five commonly used parabens in consumer products were frequently detected. After the biological treatment only two paraben were detected with concentration from 65-120 ng/L. Chlorine dioxide treatment of the biologically treated effluent with dosages down to 0.75 mg/L resulted in more than 97% reduction of all parabens. Formation of the by-product chloroform was insignificant from the chlorine dioxide treatment. 相似文献
992.
A method was developed to assess the heat insulation performance of intumescent coatings. The method consists of temperature measurements using the bench‐scaled experimental set‐up of a cone calorimeter and finite difference simulation to calculate the effective thermal conductivity dependent on time/temperature. This simulation procedure was also adapted to the small scale test furnace, in which the standard time–temperature curve is applied to a larger sample and thus which provides results relevant for approval. Investigations on temperature and calculated effective thermal conduction were performed on intumescent coatings in both experimental set‐ups using various coating thicknesses. The results correspond to each other as well as showing the limits of transferability between both fire tests. It is shown that bench‐scaled cone calorimeter tests are a valuable tool for assessing and predicting the performance of intumescent coatings in larger tests relevant for approval. The correlation fails for processes at surface temperatures above 750°C, which are not reached in the cone calorimeter, but are attained in the small scale furnace set‐up. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
993.
M Ia Bogomazov 《Voprosy pitaniia》1985,(2):56-58
Experiments on rats were made to study absorption, distribution in tissues and bioavailability of feed (internal label) and mineral (external label) cadmium-109. It was established that feed cadmium is absorbed from the gastrointestinal tract 6 times less effective as compared with an aqueous solution of cadmium chloride. In internal label, there takes place more rapid and more complete translocation of cadmium from blood plasma to red cells, whereas it bioavailability for the basic organs of deposition (kidneys, liver) is 5 times as decreased. Possible causes of the events described are discussed. 相似文献
994.
The Inter-laboratory Comparison Programme (ILCP) is a quality assurance system administered by the Dairy Division of the Ministry of Agriculture and Fisheries to monitor the performance of agency certified laboratories (ACLs). The programme works on a monthly basis during the milk producing season and is co-ordinated from the National Dairy Laboratory (NDL). Samples are despatched to Regional Dairy Labora-tories (RDL) and to the ACLs 2 weeks later. The RDL results are used to calculate an official mean. The ACL results are sent to the RDL where they are scrutinized immediately; hence, a rapid feedback on the ACL performance is possible. The NDL despatches a detailed statistical evaluation of results of ACLs and RDLs. The pro-gramme has increased from seven products in 1977 to eleven in 1984. Microbiological and chemical analyses are performed. A bacterial identification scheme to monitor E. coli and S. aureus was included in 1982. A scoring system (0 poor-10 good) which includes a weighting for specific tests and which is measured against an 'official' score has been introduced into a report which is distributed to all participants. The data generated by the programme are used by both ACLs and RDLs to check their analytical performance and quality control. Data are used by Dairy Division, as a national compilation of results issued by it which serves to highlight problem analyses, season trends and analytical limits. 相似文献
995.
Vectored transmission for digital subscriber line systems 总被引:2,自引:0,他引:2
This paper describes the "vectored" transmission technique for digital subscriber line (DSL) systems, which utilizes user coordination at the central office or optical network unit. This method exploits the colocation of the downstream transmitters and of the upstream receivers, in order to achieve far-end crosstalk (FEXT) cancellation and perform multiuser transmission optimization. The performance improvements are particularly pronounced in environments with strong FEXT such as in very high-speed DSL. Discrete multitone is employed for each user with additional constraints on the cyclic prefix length and with the assumption of block-synchronized transmission and reception for downstream and upstream transmission correspondingly. Within each tone, upstream crosstalk is removed by multiple-input-multiple-output decision feedback at the receiving side, while downstream crosstalk is eliminated by analogous preprocessing at the transmitting side. Additionally, the issue of transmission energy allocation in frequency and among users is addressed. Assuming frequency-division duplexing, the corresponding optimization problem is formulated and solved via convex programming both for a fixed upstream-downstream band plan and for a dynamically programmable band plan. The case of power backoff as a means to reduce the impact of crosstalk on alien systems is also treated. Interestingly, the performance of the proposed methods is shown to be very close to known information theory bounds 相似文献
996.
Polyurethanes were prepared from pure 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butane diol (BDO) or 1,2-ethane diol (EDO) and α,ω-hydroxyl poly(propylene oxide) (PPO) by reaction injection moulding (RIM). Hard segment (MDI + BDO or EDO) level was 45–50 wt%. The PPO had about 20% ethylene oxide copolymerized in at the chain ends to provide 80% primary OH end groups. Mn was varied from 2000 to 4000. Dibutyl tin dilaurate catalyst and mould temperature were varied. Dynamic mechanical, wide-angle X-ray, differential scanning calorimeter, molecular weight and tensile elongation measurements were made on the RIM polyurethanes. At low reaction rates (low catalyst or temperature) highly crystalline, well phase separated but low molecular weight polymers were produced. At high catalyst or temperature levels more poorly phase separated but high molecular weight, tough polymers resulted. Higher Mn PPO gave better phase separation and EDO gave higher melting temperatures. Preventing hard segment crystallinity by substituting asymmetric MDI or glycols resulted in phase compatibility. 相似文献
997.
998.
999.
Taganrog Metallurgical Plant. Translated form Metallurg, No. 11, p. 34, November, 1989. 相似文献
1000.