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161.
Michael J. Mason Jeremy Mennis J. Douglas Coatsworth Thomas Valente Frank Lawrence Patricia Pate 《Journal of environmental psychology》2009
Geographic and substance use data were collected from 301 urban adolescents to compare the perceived and observed risk and safety associated with their home and activity space locations (routine locations). The geographic characteristics of the neighborhood surrounding each location was summarized according to features theorized to be risky, such as criminal activity and alcohol sales, and features theorized to be safe, such as recreation centers and churches. Data on socioeconomic status, derived from U.S. Bureau of the Census data, were also used to characterize locations. Adolescents' homes were typically perceived as safe despite observed measures of risk such as density of crimes and proximity to alcohol outlets. This held for both substance users and non-users. Differences in geographic characteristics for safe and risky activity spaces were observed for both substance users and non-users, with non-users appearing to be more sensitive to the presence of risky characteristics in the environment than substance users. Results highlight the need and provide a methodology to collect fine-grained activity space data instead of relying only on home residence when attempting to represent place and health behaviors with urban youth. 相似文献
162.
Jones K Lanthier Y van der Voet P van Valkengoed E Taylor D Fernández-Prieto D 《Journal of environmental management》2009,90(7):2154-2169
The overall objective of the Ramsar Convention, signed in 1971, is the conservation and wise use of wetlands by national action and international cooperation as a means to achieving sustainable development. This complex and challenging task requires national, local and international bodies involved in the implementation of the convention to rely on suitable geo-information to better understand wetland areas, complete national inventories, perform monitoring activities, carry out assessments and put in practice suitable management plans based on updated and reliable information. In the last years, Earth Observation (EO) technology has been revealed as a key tool and unique information source to support the environmental community in different application domains, including wetlands' conservation and management. In this context, the European Space Agency (ESA) in collaboration with the Ramsar Secretariat launched in 2003 the "GlobWetland" project in order to demonstrate the current capabilities of Earth Observation technology to support inventorying, monitoring, and assessment of wetland ecosystems. This paper collects the main results and findings of the "GlobWetland" project, providing an overview of the current capabilities and limits of EO technology as a tool to support the implementation of the Ramsar Convention. The project was carried out in collaboration with several regional, national and local conservation authorities and wetland managers, involving 50 different wetlands across 21 countries on four continents. This large range of users provided an excellent test bed to assess the potential of this technology to be applied in different technical, economic and social conditions. 相似文献
163.
Diego Simón Ana Maria Borreguero Antonio de Lucas Carolina Molero Juan Francisco Rodríguez 《Journal of Material Cycles and Waste Management》2014,16(3):525-532
Flexible polyurethane foams can be advantageously treated by two-phase glycolysis in order to recover polyols with improved quality. The bottom phase obtained, which contains highly toxic reaction by-products and the excess glycol, presents an environmental and economic problem which should be solved. The main purpose of this work is the development of process for the valorization of these by-products, converting them in non-dangerous and profitable substances. For this process, most of the glycol can be recovered by means of vacuum distillation in order to reuse it in the glycolysis. On the other hand, the vacuum residue, containing the isocyanate part of the glycolysis by-products, was assayed as initiator in the synthesis of new polyols. Propoxylation of the initiator was carried out in different experimental conditions to obtain several polyether-polyols. Rigid polyurethane foams with suitable technical properties were synthesized with those polyols synthesized with the dangerous glycolysis by-products. 相似文献
164.
Gerson Freitas Silva Valente Regina Célia Santos Mendonça José Antonio Marques Pereira Leonardo Bonato Felix 《Journal of environmental science and health. Part. B》2013,48(4):355-361
Iron electrodes were used for electrocoagulation (EC) treatment of wastewater from a dairy plant. Electrolysis time, pH, current density and distance between electrodes were considered to assess the removal efficiency of chemical oxygen demand (COD), total solids (TS) and their fractions and turbidity. Samples were collected from the effluent of a dairy plant using a sampling methodology proportional to the flow. The treatments were applied according to design factorial of half fraction with two levels of treatments and three repetitions at the central point. The optimization of parameters for treating dairy industry effluent by electrocoagulation using iron electrodes showed that electric current application for 15 minutes, an initial sample pH close to neutral (pH 7.0) and a current density of 50 A . m?2 resulted in a significant reduction in COD by 58 %; removal of turbidity, suspended solids and volatile suspended solids by 95 %; and a final treated effluent pH of approximately 9.5. Negative consequences of the type of electrode used were the emergence of an undesirable color and an increase in the proportion of dissolved solids in the treated effluent. 相似文献
165.
The Evolution of Particles in the Plume from a Large Coal-Fired Boiler with Flue Gas Desulfurization
Robert E. Imhoff Roger L. Tanner Ralph J. Valente Menachem Luria 《Journal of the Air & Waste Management Association (1995)》2013,63(7):1207-1214
ABSTRACT Airborne measurements were made of gaseous and particulate species in the plume of a large coal-fired power plant after flue gas desulfurization (FGD) controls were installed. These measurements were compared with measurements made before the controls were installed. The light scattering and number and volume distributions of plume excess particles were determined by nephelometry and optical particle counting techniques. The plume impact based on optical techniques was much lower than that observed in earlier measurements. Indeed, plume excess volumes as a function of particle size were of the same magnitude as the variability of the background volume distribution. In situ excess plume scattering actually decreased with distance from the source, in contrast to pre-FGD conditions. The upper limit for the dry rate of SO2-to-SO4 2- conversion was estimated from plume excess volume measurements to be about 4% lir1. This is slightly greater than the upper limit, 3.5% lir1, estimated by earlier researchers, but the same as that estimated using the present technique with the earlier data. The cross-plume profile of volume suggests SO2-to-SO4 2- conversion is highest at the plume edges. The greatest benefit of SO2 reduction on plume excess volume and visibility appears to occur far downwind of the source. 相似文献
166.
Menachem Luria Robert E. Imhoff Ralph J. Valente William J. Parkhurst Roger L. Tanner 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1408-1413
ABSTRACT The rate of conversion of SO2 to SO4 2- was re-estimated from measurements made in the plume of the Cumberland power plant, located on the Cumberland River in north-central Tennessee, after installation of flue gas desulfurization (FGD) scrubbers for SO2 removal in 1994. The ratio of SO2 to NOy emissions into the plume has been reduced to ~0.1, compared with a prescrubber value of ~2. To determine whether the SO2 emissions reduction has correspondingly reduced plume-generated particulate SO4 2- production, we have compared the rates of conversion before and after scrubber installation. The prescrubber estimates were developed from measurements made during the Tennessee Plume Study conducted in the late 1970s. The post-scrubber estimates are based upon two series of research flights in the summers of 1998 and 1999. During two of these flights, the Cumberland plume did not mix with adjacent power plant plumes, enabling rate constants for conversion to be estimated from samples taken in the plume at three downwind distances. Dry deposition losses and the fact the fact that SO2 is no longer in large excess compared with SO4 2- have been taken into account, and an upper limit for the conversion rate constant was re-estimated based on plume excess aerosol volume. The estimated upper limit values are 0.069 hr-1 and 0.034 hr-1 for the 1998 and 1999 data, respectively. The 1999 rate is comparable with earlier values for nonscrubbed plumes, and although the 1998 upper limit value is higher than expected, these estimates do not provide strong evidence for deviation from a linear relationship between SO2 emissions and SO4 2- formation. 相似文献
167.
Valente GF Santos Mendonça RC Pereira JA Felix LB 《Journal of environmental science and health. Part. B》2012,47(4):355-361
Iron electrodes were used for electrocoagulation (EC) treatment of wastewater from a dairy plant. Electrolysis time, pH, current density and distance between electrodes were considered to assess the removal efficiency of chemical oxygen demand (COD), total solids (TS) and their fractions and turbidity. Samples were collected from the effluent of a dairy plant using a sampling methodology proportional to the flow. The treatments were applied according to design factorial of half fraction with two levels of treatments and three repetitions at the central point. The optimization of parameters for treating dairy industry effluent by electrocoagulation using iron electrodes showed that electric current application for 15 minutes, an initial sample pH close to neutral (pH 7.0) and a current density of 50 A (.)(m-2) resulted in a significant reduction in COD by 58 %; removal of turbidity, suspended solids and volatile suspended solids by 95 %; and a final treated effluent pH of approximately 9.5. Negative consequences of the type of electrode used were the emergence of an undesirable color and an increase in the proportion of dissolved solids in the treated effluent. 相似文献
168.
Chemometrics are increasingly used in environmental monitoring studies, but are still far from being accepted as routine tools by field specialists. The multivariate character of usually highly correlated environmental data recommends the use of advanced chemometrics as part of the analytical methodology in order to get information on the basic structure of data. In this work, we have applied a battery of non-supervised (Principal Component Analysis (PCA)) and supervised (k-Nearest Neighbour (k-NN), Soft Independent Modelling of Class Analogies (SIMCA), Linear Discriminant Analysis (LDA) and Artificial Neural Networks (ANNs)) multivariate techniques on a specific environmental dataset. The dataset consists on the concentration of 14 elements (Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, V and Zn) in 95 sediments collected at eight different locations of the estuary of the Nerbioi-Ibaizabal River (Bilbao, Basque Country) during 12 sampling campaigns conducted every 3 months between 2005 and 2008. The study aims to present a simple methodology of general applicability which may result in a flexible and practical tool to assess chemical pollution in sediments of a given specific site. 相似文献
169.
Arturo Torres-Dosal Rebeca Isabel Martinez-Salinas Diego Hernandez-Benavides Francisco Javier Perez-Vazquez Cesar Ilizaliturri-Hernandez Ivan Nelinho Perez-Maldonado 《Environmental monitoring and assessment》2012,184(12):7551-7559
In Mexico, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) was used until the year 2000, principally in agriculture and anti-paludal program health campaigns. The southeastern region of Mexico was an important area of malaria, and from 1957 DDT was applied indoors every 6?months, with a coverage of 2?g/m2. The current study was performed in Tabasco, a Mexican state located in the southeastern region of Mexico. DDT and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (DDE) were analyzed by gas chromatography/mass spectrometry. In general, low levels were found in household outdoor samples; the levels of DDT ranged from not detectable to 0.048?mg/kg, and of DDE from 0.001 to 0.068?mg/kg. An important finding was that, in all communities where DDT in blood was analyzed, exposure to DDT was found, indicating both past and present exposure. Although the levels found in this study were lower than other studies in Mexico, there is a need to evaluate whether the people living in the study area are at risk. 相似文献
170.
Diego Ruiz-Labourdette María F. Schmitz Carlos Montes Francisco D. Pineda 《Environmental Modeling and Assessment》2010,15(6):531-547
The Madrid Regional Government (Central Spain) proposes a zone of the Guadarrama Mountains to be declared as a National Park.
This paper reports on the zoning method developed to this end. The procedure followed considers compatibility of land uses
with landscape characteristics and proposes protecting a part of the zone through declaration of National Park status and
declaring another part as a Regional Park. The approach is based upon a multivariate environmental analysis aimed at zoning
for optimal location of potential activities. The zoning permits the design of protected areas following the criteria underlying
the declaration of these two categories in accordance with the Spanish environmental legislation in force. A practical tool
for policy decision-making is provided. However, the final decision taken by policymakers in the design and zoning of protected
areas differed from the model output used by the scientists. This is discussed in the paper to illustrate the interactions
between political decision-making and scientific modelling. 相似文献