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排序方式: 共有169条查询结果,搜索用时 12 毫秒
41.
Ojha Ankita Tiwary Dhanesh Oraon Ramesh Singh Pardeep 《Environmental science and pollution research international》2021,28(24):30573-30594
Environmental Science and Pollution Research - Although water occupies 75% of the earth’s surface, only 0.0067% of the total water is available for human activities. These statistics further... 相似文献
42.
Quick BL Stephenson MT Witte K Vaught C Booth-Butterfield S Patel D 《Journal of Safety Research》2008,39(3):329-338
PROBLEM: The National Institute for Occupational Safety and Health's [NIOSH] National Occupational Research Agenda (DHHS Publication No. 96-115) reports that approximately 50% of miners will experience hearing loss by age 50, compared to only 9% of the general population. The present investigation examines three antecedents believed to be associated with miner's use of hearing protection. METHOD: A posttest-delayed-posttest-control group field research design was employed to assess antecedents toward wearing hearing protection. RESULTS: Following the initial posttest, miners' attitudes and subjective norms were antecedents to intentions to wear hearing protection devices. Also, intentions toward wearing hearing protection predicted hearing protection behaviors. Approximately six weeks later, miners' attitudes and perceived behavioral control were each significant predictors of intentions to wear hearing protection and again, intentions were positively associated with hearing protection behaviors. IMPACT ON INDUSTRY: Our results indicate that appeals to normative influences may be the most effective antecedent to employ when persuading coal miners to wear hearing protection. However, messages designed to impact attitudes and perceived behavioral control were also effective. 相似文献
43.
Stephenson MT Witte K Vaught C Quick BL Booth-Butterfield S Patel D Zuckerman C 《Journal of Safety Research》2005,36(1):9-17
INTRODUCTION: This longitudinal field study was designed to encourage Appalachian coal miners in West Virginia and Pennsylvania to engage in hearing-protection behaviors. METHOD: Participants were mailed postcards that featured either a positive, negative, or neutral message on the outside of the postcard and a message encouraging hearing protection behaviors on the inside. The first posttest measurement of the effectiveness of the persuasive messages was conducted about a week after the postcards were mailed. The delayed posttest measurement was conducted six weeks later. RESULTS: Responses from 307 coal miners revealed that the positive or neutral messages generated significantly more self-reported hearing protection behaviors than the negative message. Identical results were obtained in a delayed posttest assessment of miners' self-reported hearing protection behaviors. The positive message was also more effective than either the neutral or negative message in preventing defensive mechanisms from emerging over time. IMPACT ON INDUSTRY: Positive and neutral messages were convincingly more successful than negative messages in facilitating self-reported hearing protection behaviors among coal miners. Similarly, the positive messages kept defensive processes at bay. 相似文献
44.
The paper describes the training, validation and application of artificial neural network (ANN) models for computing the dissolved oxygen (DO) and biochemical oxygen demand (BOD) levels in the Gomti river (India). Two ANN models were identified, validated and tested for the computation of DO and BOD concentrations in the Gomti river water. Both the models employed eleven input water quality variables measured in river water over a period of 10 years each month at eight different sites. The performance of the ANN models was assessed through the coefficient of determination (R2) (square of the correlation coefficient), root mean square error (RMSE) and bias computed from the measured and model computed values of the dependent variables. Goodness of the model fit to the data was also evaluated through the relationship between the residuals and model computed values of DO and BOD. The model computed values of DO and BOD by both the ANN models were in close agreement with their respective measured values in the river water. Relative importance and contribution of the input variables to the model output was evaluated through the partitioning approach. The identified ANN models can be used as tools for the computation of water quality parameters. 相似文献
45.
Ingrid Christine Koch Coleen Vogel Zarina Patel 《Mitigation and Adaptation Strategies for Global Change》2007,12(8):1323-1339
Climate change is a multi-dimensional issue and in terms of adaptation numerous state and non-state actors are involved from
global to national and local scales. The aim of this paper is first to analyse specific institutional networks involved in
climate change predominantly at the national level in South Africa and second to determine how different stakeholders perceive
their role vis-a-vis climate change adaptation. Within the South African context there is a gap in understanding and evaluating
how institutional networks operate and thus the findings of this work may help inform and strengthen such relationships in
the future. Results showed that few institutions fully understand the implications of adaptation and their roles and responsibilities
have not yet been properly defined. Constraints relating to capacity, lack of awareness and poor information flow need to
be addressed. Climate change is perceived as an important issue although problems such as poverty reduction and job creation
remain national priorities. Most importantly this research has demonstrated how adaptation challenges the hierarchical manner
in which government works and a more collaborative approach to climate change adaptation is needed. Adaptation needs to be
mainstreamed and institutional networks need to be strengthened in order for adaptation mechanisms to be effectively implemented.
相似文献
Ingrid Christine KochEmail: |
46.
C.J. EnnisK.K. Botros C. Patel 《Journal of Loss Prevention in the Process Industries》2011,24(1):111-121
Shell-tube type heat exchangers are often used to exchange heat between a high-pressure fluid and a low-pressure fluid. The pressure difference between these two fluids could be significantly high. In the event of a partial or full rupture of a tube, a problem may arise in that a transient pressure rise phenomenon could occur due to the flashing of the high-pressure sub-cooled fluid in the tube into the low-pressure shell, which may cause the shell to rupture with subsequent damage to equipment. This paper presents a dynamic model to describe the transient phenomenon occurring on the shell side following various scenarios of tube rupture. The spatial and temporal aspects of the flow transients along the pressure safety valve riser are accounted for by solving the one-dimensional continuity and momentum hyperbolic partial differential equations as applied to the liquid-filled riser. The dynamics of the attached piping system are also accounted for via two mechanistic models; the first is based on an inertial-resistive assumption of the fluids in this system, while the other is based on the assumption of anechoic perturbations passing through a long section of the attached piping. The latter is justified in cases where the attached piping is long enough such that reflections from the downstream end do not interfere with transients occurring in the shell during the initial phase of fluid flashing into the shell side following rupture. The various phases of this phenomenon are described, however the paper focuses on the initial phase of the phenomenon during which shell overpressure may be encountered. The model is applied to two ethylene heaters in tandem; the first uses propylene on the shell side to heat the ethylene on the tube side, while the second uses methanol, also on the shell side. The ratio between the shell design pressure to the tube design pressure in these two heaters are 0.169 and 0.154, respectively, hence the motivation to accurately model the transients involved in this phenomenon. The practical aspects and discussion around techniques to alleviate potential overpressure scenarios due to tube rupture are emphasized throughout the paper. 相似文献
47.
Benjamin Okang’ Odumo Gregoria Carbonell Hudson Kalambuka Angeyo Jayanti Purshottam Patel Manuel Torrijos José Antonio Rodríguez Martín 《Environmental science and pollution research international》2014,21(21):12426-12435
This work considered the environmental impact of artisanal mining gold activity in the Migori–Transmara area (Kenya). From artisanal gold mining, mercury is released to the environment, thus contributing to degradation of soil and water bodies. High mercury contents have been quantified in soil (140 μg kg?1), sediment (430 μg kg?1) and tailings (8,900 μg kg?1), as expected. The results reveal that the mechanism for transporting mercury to the terrestrial ecosystem is associated with wet and dry depositions. Lichens and mosses, used as bioindicators of pollution, are related to the proximity to mining areas. The further the distance from mining areas, the lower the mercury levels. This study also provides risk maps to evaluate potential negative repercussions. We conclude that the Migori–Transmara region can be considered a strongly polluted area with high mercury contents. The technology used to extract gold throughout amalgamation processes causes a high degree of mercury pollution around this gold mining area. Thus, alternative gold extraction methods should be considered to reduce mercury levels that can be released to the environment. 相似文献
48.
Radionuclide migration in aquatic environment is influenced by its sorption onto colloids/mineral oxides and the presence of organic complexing anions. With a view to understand the sorption of trivalent actinides by mineral oxides in presence of organic acid, in the present study, Eu(III), malonic acid (MA) and γ-alumina are considered as representatives of trivalent actinides, low molecular weight natural occurring organic acid and aluminol sites, respectively. The influence of MA on sorption of Eu(III) by γ-alumina was elucidated by batch sorption, spectroscopic techniques and surface complexation modeling, for the first time. Attenuated Total Reflection-Fourier Transform Infrared spectroscopic studies of MA sorbed on γ-alumina revealed the presence of two inner-sphere surface complexes. Batch sorption for binary (alumina-Eu(III)) and ternary (alumina-Eu(III)-MA) systems were investigated as a function of pH, Eu(III) concentration and sequential addition of Eu(III)/MA. The pH edge for Eu(III) sorption shifts to higher pH with increasing Eu(III) concentration. In ternary systems, Eu(III) sorption is significantly enhanced at pH < 4.5. Eu(III) speciation on γ-alumina is independent of addition sequence of Eu(III)/MA. Time resolved fluorescence spectroscopy of Eu(III) sorbed on γ-alumina exhibited two surface species, XOEu2+ and (YO)2Eu+. The enhancement in I616/I592 and lifetime for ternary systems, as compared to binary system, at low pH, indicates the participation of Eu-MA complexes in the formation of surface species in ternary systems. The diffuse layer model has been employed to successfully model the experimental sorption profiles of binary and ternary systems, using code FITEQL 4.0, by considering the surface species identified by spectroscopic techniques. 相似文献
49.
Chronic elevated nitrogen (N) deposition has altered the N status of temperate forests, with significant implications for ecosystem function. The Bear Brook Watershed in Maine (BBWM) is a whole paired watershed manipulation experiment established to study the effects of N and sulfur (S) deposition on ecosystem function. N was added bimonthly as (NH4)2SO4 to one watershed from 1989 to 2016, and research at the site has studied the evolution of ecosystem response to the treatment through time. Here, we synthesize results from 27 years of research at the site and describe the temporal trend of N availability and N mineralization at BBWM in response to chronic N deposition. Our findings suggest that there was a delayed response in soil N dynamics, since labile soil N concentrations did not show increases in the treated watershed (West Bear, WB) compared to the reference watershed (East Bear, EB) until after the first 4 years of treatment. Labile N became increasingly available in WB through time, and after 25 years of manipulations, treated soils had 10× more extractable ammonium than EB soils. The WB soils had 200× more extractable nitrate than EB soils, driven by both, high nitrate concentrations in WB and low nitrate concentrations in EB. Nitrification rates increased in WB soils and accounted for ~?50% of net N mineralization, compared to ~?5% in EB soils. The study provides evidence of the decadal evolution in soil function at BBWM and illustrates the importance of long-term data to capture ecosystem response to chronic disturbance. 相似文献
50.
Alok Kumar Vikram Bhardwaj Jitendra Nath Tiwari Devendra Kumar Patel Dhruv Sen Singh Ram Lakhan Singh 《毒物与环境化学》2013,95(2):373-381
Amyotrophic lateral sclerosis (ALS), a progressive disorder that usually runs a fatal course within 2–5 years of onset, is characterized by loss of motor neurons in the cortex, brain stem, and spinal cord. In this study mercury (Hg) concentrations were determined in blood samples of 40 ALS patients, of whom 24 ALS patients were from the Ganga plain region and their metal levels were found to be significantly higher. In contrast, Hg levels in the 16 ALS patients from non-Ganga plain regions whose levels were similar to those of the control subjects. Mercury in stream water samples and freshly deposited stream sediment were determined in the locations of patients’ native residences along the Ganga plain region and metal levels were found to be higher than the threshold guideline values for Hg in stream waters recommended by WHO. The geo-accumulation index in selected sites of freshly deposited stream sediment ranged from moderate to highly polluted. The high levels of Hg observed in ALS patients may potentially alter the redox status of neuronal cell components and induce cell-death pathways. 相似文献