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41.
John M. Onyari Francis Mulaa Joshua Muia Paul Shiundu 《Journal of Polymers and the Environment》2008,16(3):205-212
In this study, the biodegradation of PLA films using microorganisms from Lake Bogoria (Kenya) were investigated. The biodegradation
tests done using certain strains of thermophilic bacteria showed faster biodegradation rates and demonstrated temperature
dependency. The biodegradation of the PLA films was studied using Gel Permeation Chromatography (GPC) and light microscopy.
The biodegradation of PLA was demonstrated by decrease in molecular weight. The preparation and characterization of PLA/Gum
Arabic blends were also investigated using DSC, TGA, TMA and NMR. In summary, the results obtained in this research show that
PLA films undergo fast biodegradation using thermophiles isolated from Lake Bogoria. The PLA/GA blends studies show it is
possible to prepare films of varying hydrophobic–hydrophilic properties for various applications. 相似文献
42.
LEAP是由斯德哥尔摩环境研究所(SEI)波士顿中心领导的一项合作项目,旨在为一体化的能源环境分析建立一套新的分析软件和数据库.LEAP2000项目的产品应尽早获得以广为传播. 相似文献
43.
The Bias of Complementarity Hotspots toward Marginal Populations 总被引:3,自引:1,他引:2
Abstract: It has been suggested that using complementarity to identify networks of important areas for conserving biodiversity may preferentially select areas within the margins of species ranges. We tested this idea by examining the location of complementarity hotspots in relation to two measures of range core-periphery. The first measures patterns of aggregation among records within each species' range to identify areas within the core (i.e., areas with aggregated distributions) and periphery (i.e., areas with scattered distributions) of the range. The second measures spatial turnover among species to identify areas with a high density of range edges. For three selected groups of terrestrial vertebrates in Europe—mammals, birds, and herptiles—areas chosen based on complementarity were located within the margins of species' ranges more often than expected by chance. This pattern was consistent for the two measures of core-periphery we used. The bias of complementarity hotspots toward marginal populations is especially important for species with restricted range sizes. If extinctions are determined mainly by demographic factors, then selecting areas at the peripheries of species' ranges might be a poor option. But if extinctions are determined mainly by extrinsic factors, then peripheral populations might be important to ensure the long-term persistence of species. 相似文献
44.
45.
Fernando Rojano Pierre-Emmanuel Bournet Melynda Hassouna Paul Robin Murat Kacira Christopher Y. Choi 《Environmental monitoring and assessment》2018,190(12):724
Air inside poultry houses must be removed on a regular basis to prevent excess of heat, particles and noxious gases that can imperil animals. To cope with this issue, natural ventilation could be an effective method when assisted by accurate predictions. This study investigates air discharges caused by natural ventilation of a poultry house by means of a three-dimensional computational fluid dynamics (CFD) model. It solves the governing equations of momentum, heat and mass transport, radiative transfers and animal-generated heat. Wind directions of 0°, 36° and 56° (0° corresponds to a wind blowing perpendicular to the ridgeline) were investigated; the CFD model predictions achieved a RMSE of 1.2 °C and 0.6 g[H2O] kg?1 [dry air] for internal temperature and absolute humidity, respectively, when air blew with an angle of 36°. Air renewal rates (ARR) were 39.5 (±?1.9), 34.9 (±?2.2) and 33.6 (±?1.7) volumes of the building per hour, when air blew at 0°, 36° and 56°, respectively. Such ARR predictions served to know how the gases contained in air would likely spread downstream from the building in order to define regions of potentially high gas concentration that could endanger neighbouring habitable facilities. 相似文献
46.
Oguma Andrew Y. Klerks Paul L. 《Environmental science and pollution research international》2017,24(23):19076-19085
Environmental Science and Pollution Research - Pollution-induced community tolerance (PICT) has been used to demonstrate effects of sediment contamination on microbes and meiofauna. Our study... 相似文献
47.
Benassi Laura Dalipi Rogerta Consigli Veronica Pasquali Michela Borgese Laura Depero Laura E. Clegg Francis Bingham Paul A. Bontempi Elza 《Environmental science and pollution research international》2017,24(17):14834-14846
Environmental Science and Pollution Research - This work supports, for the first time, the integrated management of waste materials arising from industrial processes (fly ash from municipal solid... 相似文献
48.
U.S. National PM2.5 Chemical Speciation Monitoring Networks—CSN and IMPROVE: Description of networks
Paul A. Solomon Dennis Crumpler James B. Flanagan R.K.M. Jayanty Ed E. Rickman Charles E. McDade 《Journal of the Air & Waste Management Association (1995)》2014,64(12):1410-1438
The U.S. Environmental Protection Agency (EPA) initiated the national PM2.5 Chemical Speciation Monitoring Network (CSN) in 2000 to support evaluation of long-term trends and to better quantify the impact of sources on particulate matter (PM) concentrations in the size range below 2.5 μm aerodynamic diameter (PM2.5; fine particles). The network peaked at more than 260 sites in 2005. In response to the 1999 Regional Haze Rule and the need to better understand the regional transport of PM, EPA also augmented the long-existing Interagency Monitoring of Protected Visual Environments (IMPROVE) visibility monitoring network in 2000, adding nearly 100 additional IMPROVE sites in rural Class 1 Areas across the country. Both networks measure the major chemical components of PM2.5 using historically accepted filter-based methods. Components measured by both networks include major anions, carbonaceous material, and a series of trace elements. CSN also measures ammonium and other cations directly, whereas IMPROVE estimates ammonium assuming complete neutralization of the measured sulfate and nitrate. IMPROVE also measures chloride and nitrite. In general, the field and laboratory approaches used in the two networks are similar; however, there are numerous, often subtle differences in sampling and chemical analysis methods, shipping, and quality control practices. These could potentially affect merging the two data sets when used to understand better the impact of sources on PM concentrations and the regional nature and long-range transport of PM2.5. This paper describes, for the first time in the peer-reviewed literature, these networks as they have existed since 2000, outlines differences in field and laboratory approaches, provides a summary of the analytical parameters that address data uncertainty, and summarizes major network changes since the inception of CSN.
ImplicationsTwo long-term chemical speciation particle monitoring networks have operated simultaneously in the United States since 2001, when the EPA began regular operations of its PM2.5 Chemical Speciation Monitoring Network (IMPROVE began in 1988). These networks use similar field sampling and analytical methods, but there are numerous, often subtle differences in equipment and methodologies that can affect the results. This paper describes these networks since 2000 (inception of CSN) and their differences, and summarizes the analytical parameters that address data uncertainty, providing researchers and policymakers with background information they may need (e.g., for 2018 PM2.5 designation and State Implementation Plan process; McCarthy, 2013) to assess results from each network and decide how these data sets can be mutually employed for enhanced analyses. Changes in CSN and IMPROVE that have occurred over the years also are described. 相似文献
49.
Erlinda S. Rabano Norma T. Castillo Kahirup J. Torre Paul A. Solomon 《Journal of the Air & Waste Management Association (1995)》2013,63(1):76-80
First-time measurements of the potentially toxic inorganic species of arsenic (arsenite arid arsenate) have been obtained in fine (<2.5 µm AD) and coarse (>2.5 µm AD) atmospheric particles in the Los Angeles area. A recently developed method that includes procedures for sample collection, preparation, and analysis was used in this study. Size-fractlonated aerosol samples were collected with a high-volume dichotomous virtual impactor that employed polytetrafluoroethylene filters. Results were obtained for the recovery of arsenic standards added to unexposed and collected filters. Data from this study, indicated that the recently developed speciation method can be used to determine concentrations of As(lll) and As(V) In atmospheric particulate matter samples. Size-fractionated aerosol samples were collected in the city of Industry during January and February 1987. In most samples, As(lll) and As( V) were above the detection limit (approximately 1 ng m-3 of either species) in both aerosol size fractions. A greater portion (about 75 percent) of the two species were observed in the fine particles. The As(lll)/As(V) ratio for both particle sizes was close to 1 (I.e., an equal mixture of both species). Comparison of total suspended particulate arsenic measured by the speciation method to that measured by a routine California Air Resources Board-approved procedure showed good agreement (r = 0.94), indicating both methods were approximately equivalent for the collection and analysis of aerosol arsenic. 相似文献
50.
Martin A. Cohen P. Barry Ryan Yukio Yanagisawa John D. Spengler Halûk Özkaynak Paul S. Epstein 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1086-1093
The Kanawha Valley region of West Virginia which is comprised of Charleston and surrounding communities Is the center of a heavily industrialized area known for its chemical manufacturing. As part of a larger study designed to investigate the Impact of the chemical industry on human exposures to volatile organic compounds (VOC), a study of the relationship between indoor and outdoor concentrations was conducted. Thirty-five homes were selected for monitoring from among volunteers; approximately ten in each of three distinct population-industry centers and four outside the Valley to act as controls. Monitoring was performed using passive, badge samplers with a three-week monitoring period. Two separate questionnaires were administered: one for characterization of the residence; and one to characterize source use during monitoring. Participants were also asked to keep a record of their activities with respect to in-home, outdoors and other Indoor environments. Analysis of the samplers was performed by solvent extraction followed by gas chromatography using a flame-ionization detector. Results suggest that indoor VOC concentrations are higher than outdoor concentrations. Additionally, certain ventilation-related parameters were identified that afforded some predictive power for indoor concentrations. No statistically significant differences between regions were identified. 相似文献