Green Infrastructure / Low Impact Development (GI/LID) is an increasingly popular strategy to manage urban stormwater for individual properties, but the aggregate effect on runoff reduction at the city scale has not been thoroughly investigated. This study examined the potential combined effects of rain barrels, cisterns, and downspout disconnections on combined sewer overflows (CSOs) for a medium-sized urban center. To support a city-wide analysis, a novel simulation strategy was implemented using the Storm Water Management Model (SWMM). In this new approach, a modeling at the source technique for subcatchment delineation was combined with a set of R-language utilities to automatically configure GI/LID management scenarios. The reconfigured SWMM model was used to examine 99 distinct management scenarios based on different sizes, numbers, and locations of the targeted GI/LID features for the city of Buffalo, New York. For a typical hydrologic year, the deployment of large residential rain barrels (1000-gallon) resulted in up to a 12% reduction in predicted CSO volume, while the inclusion of large commercial-roof cisterns (5000-gallon) contributed up to an additional 12% reduction. Large variations in the predicted CSO reductions were observed across the various management scenarios, and the simulation tools were able to identify locations where the GI/LID features were most effective. In general, the modeling at the source approach and the R-language tools substantially enhanced the utility of SWMM for evaluating the effectiveness of GI/LID deployment as a CSO management strategy at the city scale, and the methodology can readily be adapted to cities with similar CSO issues.
We report upon the development of new catalytic systems for the selective hydroxylation of benzene under mild conditions. These involve the use of surfactant-transition metal salts and hydrogen peroxide. 相似文献
The two novel preconcentration and separation methods based on adsorption onto Amberlite XAD‐1180 and Amberlite XAD‐16 polymeric resins for spectrophotometric determination of sunset yellow dye were developed. The parameters, affecting the quantitative recovery, including pH, sample and eluent flow rates, eluent type, sample volume, were investigated and optimised. The interference effects of some cations, anions and widely used dye were also studied. At the optimum conditions, detection limits of the methods were found as 2.0 and 1.6 μg L?1 for Amberlite XAD‐1180 and Amberlite XAD‐16 resins, respectively. Linear dynamic ranges of the methods were obtained in the range of 0.2–50.0 and 0.2–20.0 μg mL?1 for Amberlite XAD‐1180 and Amberlite XAD‐16 resins, respectively. The relative standard deviations were below than 7% and 5% for Amberlite XAD‐1180 and Amberlite XAD‐16 resins, respectively. The determination of dye was performed at 483.0 nm using spectrophotometry. Validations of the methods were performed comparatively with determination of the sunset yellow content of some foodstuffs and pharmaceuticals. 相似文献
An investigation of the U.S. role in international biomedical publication is reported, based on counts of articles, notes and reviews in 975 biomedical journals covered by the Science Citation Index in 1973. U.S. scientists authored 42% of these biomedical papers, the U.K. 10%, West Germany and France 7% and 6%, and the U.S.S.R. 4%, a sharp change from earlier in this century when Germany and France had much more prominent roles. Overall, 94% of the papers are from OECD and Eastern European countries; only 4% are from underdeveloped regions. U.S. and U.K. papers are far more heavily cited than are papers from other countries; U.S.S.R. papers are particularly under-cited. Biomedical publication rates are shown to be highly correlated (r = 0.9) with both national wealth (GNP) and national affluence (GNP/capita). National publication rates also correlate with Nobel Prize recipients. - Frame, J. D., and F. Narin. The international distribution of biomedical publications. 相似文献
Calcium-binding peptide was derived from protein hydrolysates. In this study, tilapia protein at a concentration of 2 % (w/v) was hydrolyzed using various proteases including Alcalase 2.4 L, Flavourzyme 1,000L, Protease GN, and papain at 50 °C, pH 8 for 6 h. It was found that the degree of hydrolysis increased with the time of the incubation in all cases. The highest calcium-binding capacity of the hydrolysate was 65 mg/g protein at 27.7 % degree of hydrolysis by Alcalase 2.4 L. The molecular weight of the calcium-binding peptides characterized by gel-filtration chromatography on a Sephadex G-25 was 1.2 kDa. The calcium-binding motif of the hydrolyzed peptides identified by the automated Edman degradation was a short peptide (Trp-Glu-Trp-Leu-His-Tyr-Trp). The results of this study suggested that tilapia protein is a good source for calcium-binding peptides. 相似文献
Amberlite XAD‐7 and XAD‐8 resins were used as adsorbents for preconcentration and determination of Allura Red (AR) food dye in aqueous medium. The effects of pH, sample volume, sample and eluent flow rates on the extraction of AR were optimised. The determination of dye was performed at 506.0 nm using spectrophotometry. Interference effects of matrix ions and some dyes were also investigated under optimised conditions. The methods permitted low detection limits which were 1.2 and 0.6 μg L?1 for XAD‐7 and XAD‐8, respectively. Adsorption behaviours were investigated by adsorption isotherms and zero charge pH experiments. Validations of the method were performed by determination of AR contents in some foodstuffs. AR contents of liquid samples were found between 58 and 440 μg mL?1. AR concentrations of solid samples were between 416 and 432 μg g?1. The XAD‐7 and XAD‐8 resins presented a fast and reliable potential to determine AR dye in real samples. 相似文献
A country by subject count of the serial periodical collection at the British Library Lending Division (BLLD) in 1973 is reported and compared to previous counts. Approximately 25 000 periodicals have titles indicating that they are scientific journals in nine fields of the physical and biological sciences, engineering, and mathematics. The overall subject distribution of the journals appears to be remarkably stable when compared to a similar count byHulme 60 years ago, although the number of journals appears to have doubled in the last 60 years. A major shift was found in the national origin of the journals, when compared withHulme's counts, with a notable rise in the number and percent of U.S. journals, and a sharp decline in the percentage of French and German journals. 相似文献
A unification of more than one million non-patent references (NPR's) on the front pages of U.S. and EPO patents has been carried
out, with a subsequent match to theScience Citation Index (SCI), in order to investigate the citation linkage between patented technology and the scientific research literature. The U.S.
system shows an extremely rapid increase in linkage, with citations from U.S. patents to U.S. authored papers increasing more
than three-fold over the last decade. The EPO system does not show any increase; the occurrence of non-patent references appears
to be relatively constant in the EPO system over the last decade. In the U.S. system approximately 75 percent of the cited
papers originate in public science institutions, showing large dependence of patented industrial technology on public science.
We expect to find similar result in the EPO system. 相似文献
A conceptual framework is suggested within which various techniques for studying scientific advance may be viewed. The two axes arerelevance of the technique to a “true” measure of the rate of scientific advance, versusobjectivity of the technique. It is suggested that a situation exists somewhat analogous to the Heisenberg uncertainty, principle; the most objective technique, a simple publication count, is the least relevant to a true measure of scientific advance, while the most relevant technique, interviews with an eminent and knowledgeable scientist in the field, is the least objective. Between these two extremes lie a group of scientometric techniques which should be capable of producing analyses which are both satisfactorilly relevant and satisfactorily objective. 相似文献
Directional communication in wireless sensor networks minimizes interference and thereby increases reliability and throughput of the network. Hence, directional wireless sensor networks (DWSNs) are fastly attracting the interests of researchers and industry experts around the globe. However, in DWSNs the conventional medium access control protocols face some new challenges including the synchronization among the nodes, directional hidden terminal and deafness problems, etc. For taking the advantages of spatial reusability and increased coverage from directional communications, a low duty cycle directional Medium Access control protocol for mobility based DWSNs, termed as DCD-MAC, is developed in this paper. To reduce energy consumption due to idle listening, duty cycling is extensively used in WSNs. In DCD-MAC, each pair of parent and child sensor nodes performs synchronization with each other before data communication. The nodes in the network schedule their time of data transmissions in such a way that the number of collisions occurred during transmissions from multiple nodes is minimized. The sensor nodes are kept active only when the nodes need to communicate with each other. The DCD-MAC exploits localized information of mobile nodes in a distributed manner and thus it gives weighted fair access of transmission slots to the nodes. As a final point, we have studied the performance of our proposed protocol through extensive simulations in NS-3 and the results show that the DCD-MAC gives better reliability, throughput, end-to-end delay, network lifetime and overhead comparing to the related directional MAC protocols. 相似文献