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981.
ABSTRACT: The primary objective of this study was to perform a cost‐benefit analysis of maintaining the current level of water quality in the Catawba River basin. Economic benefits were estimated using a stated preference survey method designed to value respondents' willingness to pay for a management plan to protect water quality in the Catawba basin over time. From the surveys conducted with 1,085 area residents, we calculated an annual mean willingness to pay of $139 for the management plan, or more than $75.4 million for all taxpayers in the area. Over the five‐year time horizon in which respondents were asked to pay for the management plan, this resulted in a total economic benefit of $340.1 million. The Watershed Analysis Risk Management Framework model was used to estimate the amount of management activities needed to protect the current level of water quality in the basin over time. Based on the model results, the total cost of the management plan was calculated to be $244.8 million over a ten‐year period. The resulting cost‐benefit analysis indicated that the potential benefits of this management plan would outweigh the costs by more than $95 million.  相似文献   
982.

Climate change issues are calling for advanced methods to produce materials and fuels in a carbon–neutral and circular way. For instance, biomass pyrolysis has been intensely investigated during the last years. Here we review the pyrolysis of algal and lignocellulosic biomass with focus on pyrolysis products and mechanisms, oil upgrading, combining pyrolysis and anaerobic digestion, economy, and life cycle assessment. Products include oil, gas, and biochar. Upgrading techniques comprise hot vapor filtration, solvent addition, emulsification, esterification and transesterification, hydrotreatment, steam reforming, and the use of supercritical fluids. We examined the economic viability in terms of profitability, internal rate of return, return on investment, carbon removal service, product pricing, and net present value. We also reviewed 20 recent studies of life cycle assessment. We found that the pyrolysis method highly influenced product yield, ranging from 9.07 to 40.59% for oil, from 10.1 to 41.25% for biochar, and from 11.93 to 28.16% for syngas. Feedstock type, pyrolytic temperature, heating rate, and reaction retention time were the main factors controlling the distribution of pyrolysis products. Pyrolysis mechanisms include bond breaking, cracking, polymerization and re-polymerization, and fragmentation. Biochar from residual forestry could sequester 2.74 tons of carbon dioxide equivalent per ton biochar when applied to the soil and has thus the potential to remove 0.2–2.75 gigatons of atmospheric carbon dioxide annually. The generation of biochar and bio-oil from the pyrolysis process is estimated to be economically feasible.

  相似文献   
983.

Water pollution and the unsustainable use of fossil fuel derivatives require advanced catalytic methods to clean waters and to produce fine chemicals from modern biomass. Classical homogeneous catalysts such as sulfuric, phosphoric, and hydrochloric acid are highly corrosive and non-recyclable, whereas heterogeneous catalysts appear promising for lignocellulosic waste depolymerization, pollutant degradation, and membrane antifouling. Here, we review the use of sulfonated graphene and sulfonated graphene oxide nanomaterials for improving membranes, pollutant adsorption and degradation, depolymerization of lignocellulosic waste, liquefaction of biomass, and production of fine chemicals. We also discuss the economy of oil production from biomass. Sulfonated graphene and sulfonated graphene oxide display an unusual large theoretical specific surface area of 2630 m2/g, allowing the reactants to easily enter the internal surface of graphene nanosheets and to reach active acid sites. Sulfonated graphene oxide is hydrophobic and has hydrophilic groups, such as hydroxyl, carboxyl, and epoxy, thus creating cavities on the graphene nanosheet’s surface. The adsorption capacity approached 2.3–2.4 mmol per gram for naphthalene and 1-naphthol. Concerning membranes, we observe an improvement of hydrophilicity, salt rejection, water flux, antifouling properties, and pollutant removal. The nanomaterials can be reused several times without losing catalytic activity due to the high stability originating from the stable carbon–sulfur bond between graphene and the sulfonic group.

  相似文献   
984.
The Dutch Ministry of Social Affairs and Employment provided subsidy over the period 2004–2008 to a number of companies to introduce changes aimed at reducing accidents by changing their safety culture and aspects of their safety management. As part of the programme a scientific evaluation was set up to assess the effectiveness of the interventions in 17 of the projects, covering 29 companies. Before and after studies were made of the companies, documenting the state of their safety management and risk control efforts and their accident rates before the intervention, the changes made over the study period and the resulting changes in a range of measures aimed at assessing the success of the changes. The analysis led to a categorisation of the projects according to their degree of success.This paper describes the patterns of interventions distinguishing between successful and not successful projects and discusses the mechanisms lying behind them. Interventions bringing about constructive dialogue between shop-floor and line management, providing motivation to line managers and strengthening the monitoring and learning loops in the safety management system (SM) appeared more successful. The amount of energy and creativity injected by top managers and, above all, by the coordinator (safety professional) appeared also to be a distinguishing factor.  相似文献   
985.
Marie Jahoda's latent deprivation model was tested with a representative sample of the German population (N = 998). As expected, employees reported high levels of time structure, social contact, collective purpose, and activity not only in comparison to unemployed persons but also in comparison to persons who are out of the labor force (i.e., students, homemakers, retirees). Even unskilled manual workers reported more access to these “latent functions” than persons without employment. For the fifth of Jahoda's dimensions, identity/status, no significant differences between employed persons and persons who are out of the labor force could be identified. However, unemployed persons reported less status than all other groups did. Thus, Jahoda's model was clearly endorsed for four of the five latent functions of employment and partly endorsed for the fifth function. All variables in the model correlated significantly with distress, as expected. Demographic correlates of the manifest and latent functions were also analyzed: Access to the latent functions was best among young men from higher social classes who lived in an intimate relationship in a comparatively large household with children. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
986.

Introduction

The purpose of this study was to calculate national estimates and examine the extent to which children prematurely use adult seat belts and ride in the front seat of a vehicle during a 30 day period.

Methods

Data were obtained from a nationally representative cross-sectional random-digit-dial telephone survey that included child-specific questions on motor vehicle restraint use and seating position.

Results

Among children less than 13 years, parents reported an estimated 618,337 who rode unrestrained and more than one million who rode in the front seat of a vehicle at least some of the time in the past 30 days. During the same time period, close to 11 million children 8 years and younger reportedly used only adult seat belts.

Discussion

Our results highlight the need for continued outreach to parents regarding optimal restraint use and rear seating position for children every trip, every time.  相似文献   
987.
The interval sorption and diffusion of water vapor were studied for two systems: methylcellulose (MC)/starch and carboxymethylcellulose (CMC)/starch. The diffusion coefficient of water vapor and the Gibbs free energy of swelling of these blends in water were estimated. The Gibbs free energy of mixing starch with the cellulose derivatives was determined using the thermodynamic cycle. CMC/starch was shown to be more compatible than MC/starch. Biodegradation of these systems in the water–soil environment was measured and found to increase with the concentration of starch in its blends with cellulose derivatives.  相似文献   
988.
This study investigated the water quality variation spanning 30 years (1986–2017) in 16 catchments of Hong Kong against different urbanization indices, namely, built area fraction; population; and product of population and built area fraction. Pearson correlations of three different periods of time (1988–1990, 1998–2000, and 2015–2017) indicated that water quality trends were dependent on the urbanization index. Total solids, nitrite-nitrogen, total phosphorus, electrical conductivity, dissolved oxygen, and flow rate had significant deteriorative trends (Pearson r > 0.5 and p < 0.05) with population and product of built area and population. Results also interpreted that built area fraction and product of built area and population were the worst and best indices that represented urbanization and/or its impacts, respectively. Mann-Kendall test for the entire 30 year period showed that water quality had improved with time with respect to certain water quality parameters (e.g., dissolved oxygen, ammoniacal nitrogen and total suspended solids). The results portrayed that although the urbanization of catchments had increased with time, the river water quality with respect to many parameters showed signs of improvement and the legislative measures implemented seemed to be effective in controlling pollution.  相似文献   
989.
The purpose of this investigation was to analyze the relationship between four interviewer‐related factors and the validity of the employment interview. Using a regression approach to meta‐analysis, an analysis of 120 interview studies with a total sample size of 18,158 suggested that: (1) training should be provided to interviewers regardless of whether the interview itself (i.e. the questions and rating scales) is structured; (2) the same interviewer should be used across all applicants, especially when the interview itself is not highly structured; and (3) using a panel of interviewers does not contribute to validity, and may actually have a detrimental effect. Results for the fourth interviewer factor, taking notes during the interview, were inconclusive. Limitations and directions for future research are noted. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
990.
A procedure to optimize the design of a Permeable Adsorptive Barrier (PAB) for the remediation of a contaminated aquifer is presented in this paper. A computer code, including different routines that describe the groundwater contaminant transport and the pollutant capture by adsorption in unsteady conditions over the barrier solid surface, has been developed. The complete characterization of the chemical–physical interactions between adsorbing solids and the contaminated water, required by the computer code, has been obtained by experimental measurements. A case study in which the procedure developed has been applied to a tetrachloroethylene (PCE)-contaminated aquifer near a solid waste landfill, in the district of Napoli (Italy), is also presented and the main dimensions of the barrier (length and width) have been evaluated. Model results show that PAB is effective for the remediation of a PCE-contaminated aquifer, since the concentration of PCE flowing out of the barrier is everywhere always lower than the concentration limit provided for in the Italian regulations on groundwater quality.  相似文献   
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