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461.
We sampled residues from high-order and low-order blow-in-place detonations of mortars and projectiles filled with Composition B (Comp B), a TNT and RDX mixture. Our goals were to (1) characterize the types of explosive particles, (2) estimate the explosive 'footprint' for different munitions, and (3) estimate the mass of Comp B remaining after each detonation. The aerial deposition of Comp B particles helps estimate how large of an area is contaminated by a low-order detonation and how best to sample residue resulting from different rounds. We found that the high-order detonations deposited microgram to milligram quantities whereas the low-order detonations deposited gram quantities of Comp B. For the high-order detonations the concentration of Comp B in the residue decreased as a function of distance from the blast. The low-order tests scattered centimeter-sized chunks and millimeter-sized or smaller particles of Comp B. The chunks were randomly scattered whereas the number of millimeter-sized particles decreased with distance from the detonation. For both high- and low-order detonations we found that the smaller munitions deposited less Comp B than the larger munitions and deposited it closer to the detonation point. 相似文献
462.
Nonstructural Urban Stormwater Quality Measures: Building a Knowledge Base to Improve Their Use 总被引:1,自引:0,他引:1
This article summarizes a research project that investigated the use, performance, cost, and evaluation of nonstructural measures
to improve urban stormwater quality. A survey of urban stormwater managers from Australia, New Zealand, and the United States
revealed a widespread trend of increasing use of nonstructural measures among leading stormwater management agencies, with
at least 76% of 41 types of nonstructural measures being found to be increasing in use. Data gathered from the survey, an
international literature review, and a multicriteria analysis highlighted four nonstructural measures of greatest potential
value: mandatory town planning controls that promote the adoption of low-impact development principles and techniques; development
of strategic urban stormwater management plans for a city, shire, or catchment; stormwater management measures and programs
for construction/building sites; and stormwater management activities related to municipal maintenance operations such as
maintenance of the stormwater drainage network and manual litter collections. Knowledge gained on the use and performance
of nonstructural measures from the survey, literature review, and three trial evaluation projects was used to develop tailored
monitoring and evaluation guidelines for these types of measure. These guidelines incorporate a new evaluation framework based
on seven alternative styles of evaluation that range from simply monitoring whether a nonstructural measure has been fully
implemented to monitoring its impact on waterway health. This research helps to build the stormwater management industry’s
knowledge base concerning nonstructural measures and provides a practical tool to address common impediments associated with
monitoring and evaluating the performance and cost of these measures. 相似文献
463.
Oheneba-Dornyo Theresa Valerie Amuzu Setor Maccagnan Anna Taylor Timothy 《Environmental Modeling and Assessment》2022,27(3):473-489
Environmental Modeling & Assessment - Malaria has a significant impact on the lives of many in Ghana. It is one of the key causes of mortality and morbidity, resulting in 32.5% of outpatient... 相似文献
464.
John R. Post Hillary G. M. Ward Kyle L. Wilson George L. Sterling Ariane Cantin Eric B. Taylor 《Conservation biology》2022,36(3):e13783
Use of extensive but low-resolution abundance data is common in the assessment of species at-risk status based on quantitative decline criteria under International Union for Conservation of Nature (IUCN) and national endangered species legislation. Such data can be problematic for 3 reasons. First, statistical power to reject the null hypothesis of no change is often low because of small sample size and high sampling uncertainty leading to a high frequency of type II errors. Second, range-wide assessments composed of multiple site-specific observations do not effectively weight site-specific trends into global trends. Third, uncertainty in site-specific temporal trends and relative abundance are not propagated at the appropriate spatial scale. A common result is the propensity to underestimate the magnitude of declines and therefore fail to identify the appropriate at-risk status for a species. We used 3 statistical approaches, from simple to more complex, to estimate temporal decline rates for a designatable unit (DU) of rainbow trout in the Athabasca River watershed in western Canada. This DU is considered a native species for purposes of listing because of its genetic composition characterized as >0.95 indigenous origin in the face of continuing introgressive hybridization with introduced populations in the watershed. Analysis of abundance trends from 57 time series with a fixed-effects model identified 33 sites with negative trends, but only 2 were statistically significant. By contrast, a hierarchical linear mixed model weighted by site-specific abundance provided a DU-wide decline estimate of 16.4% per year and a 3-generation decline of 93.2%. A hierarchical Bayesian mixed model yielded a similar 3-generation decline trend of 91.3% and the posterior distribution showed that the estimate had a >99% probability of exceeding thresholds for an endangered listing. We conclude that the Bayesian approach was the most useful because it provided a probabilistic statement of threshold exceedance in support of an at-risk status recommendation. 相似文献
465.
Ofei-Quartey Muriel Naa Lamiokor Appiah-Effah Eugene Akodwaa-Boadi Kofi Ampaw Barnabas Taylor Theodora Sophia Millogo Zouma Emeline Nadège 《Journal of Material Cycles and Waste Management》2023,25(3):1560-1580
Journal of Material Cycles and Waste Management - Co-composting, a circular economy approach to waste management, has economic potential and environmental benefits through nutrient recycling and... 相似文献