Multi-Destination and Multi-Purpose Trip Effects in the Analysis of the Demand for Trips to a Remote Recreational Site

One of the basic assumptions of the travel cost method for recreational demand analysis is that the travel cost is always incurred for a single purpose recreational trip. Several studies have skirted around the issue with simplifying assumptions and dropping observations considered as nonconventional holiday-makers or as nontraditional visitors from the sample. The effect of such simplifications on the benefit estimates remains conjectural. Given the remoteness of notable recreational parks, multi-destination or multi-purpose trips are not uncommon. This article examines the consequences of allocating travel costs to a recreational site when some trips were taken for purposes other than recreation and/or included visits to other recreational sites. Using a multi-purpose weighting approach on data from Gros Morne National Park, Canada, we conclude that a proper correction for multi-destination or multi-purpose trip is more of what is needed to avoid potential biases in the estimated effects of the price (travel-cost) variable and of the income variable in the trip generation equation.     

The research on extracting the information of human errors in the main control room of nuclear power plants by using Performance Evaluation Matrix

Digitalized nuclear instruments and control systems have been the main stream design for the main control room (MCR) of advanced nuclear power plants (NPPs) nowadays. Digitalization of human–system interface (HSI) could improve human performance and, on the other hand, could reduce operators’ situation awareness as well. It might cause that humans make wrong decision during an emergency unintentionally. Besides, digital HSI relies on computers to integrate system information automatically instead of human operation. It has changed the operator’s role from mainly relating operational activity to mainly relating monitoring. However, if the operators omit or misjudge the information on the video display units and wide display panel, the error of omission and error of commission may occur. This study applies Content Category Analysis (CCA) and Performance Evaluation Matrix (PEM) methods to explore the potential problems in the MCR of advanced NPPs which are caused by human errors. The results show that the potential problems that would probably contribute to the human performance of MCR in the advanced NPPs are multiple accidents, pressure level, number of operators, and other factors such as working environmental. The conclusions of this research may be considered to avoid and prevent human errors in the human factor related researches especially in the nuclear safety field.     

Ethylene Dosages in Denver and Marketability of Cut-Flower Carnations

Ethylene dosages required to reduce keeping life of the cut-flower, Dianthus caryophyllus L. cv “White Sim,” were compared with dosages estimated from air samples obtained in selected locations of the Denver Metropolitan region. Ethylene concentrations sufficiently high and prolonged to reduce significantly flower longevity prior to final sale are seldom attained. If flowers are harvested in an immature stage and immediately refrigerated, there should not be any economic loss. But, damage is likely after the flower is purchased and displayed at room temperature. Regardless of quality maintained in the marketing processes by the greenhouse industry, severe consumer dissatisfaction may result when ethylene sensitive plant material is purchased. The results emphasize means of avoiding pollution damage from ethylene.     

An Aquifer Vulnerability Assessment of the Paluxy Aquifer, Central Texas, USA, Using GIS and a Modified DRASTIC Approach

D epth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone, and Conductivity of the aquifer). Using such an approach allows one to investigate the potential for groundwater contamination on a regional, rather than site-specific, scale. Based upon data from variables such as soil permeability, depth to water, aquifer hydraulic conductivity, and topography, subjective numerical weightings have been assigned according to the variable's relative importance in regional groundwater quality. The weights for each variable comprise a GIS map layer. These map layers are combined to formulate the final groundwater pollution potential map. Using this method of investigation, the pollution potential map for the study area classifies 47% of the area as having low pollution potential, 26% as having moderate pollution potential, 22% as having high pollution potential, and 5% as having very high pollution potential.     

EIA-Learning from Experience: Changes in the Quality of Environmental Impact Statements for UK Planning Projects

This paper draws on a research report recently produced (1996) by the authors for the UK Department of the Environment. The principal aim of the research was to establish clearly what changes, if any, there have been in the quality of Environmental Impact Statements (EISs) since the inception of mandatory EIA in 1988, and to explain reasons for the changes. The paper provides a critique of the meaning of 'quality' in an area such as this. Quality relates both to the EIS and to the EIA process. EIS quality can be assessed against various review frameworks in a structured and systematic way; quality can also be assessed according to the perspective of the individual participant in the EIA process. The findings of both macro and micro studies of quality are discussed. The macro study uses a range of review frameworks (minimum regulatory requirements, an EU framework, and comprehensive frameworks developed by EIA academics at UK universities, including Oxford Brookes University) for a large sample of EISs. The micro study uses a structured questionnaire of the participants (local planning officers, developers, consultants and others) involved in a smaller set of detailed case studies. The findings reveal that there has been a learning from experience and an improvementin quality, but they also highlight a number of problems in the EIA process. The paper outlines some of the determinants of the changes in quality, and concludes with recommendations for developments in EIA in response to particular issues raised. These recommendations are set in the context of European Commission amendments to the EC EIA Directive.     

Carbon bed mercury emissions control for mixed waste treatment

Mercury has various uses in nuclear fuel reprocessing and other nuclear processes, and so it is often present in radioactive and mixed (radioactive and hazardous) wastes. Compliance with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards can require off-gas mercury removal efficiencies up to 99.999% for thermally treating some mixed waste streams. Test programs have demonstrated this level of off-gas mercury control using fixed beds of granular sulfur-impregnated activated carbon. Other results of these tests include (1) the depth of the mercury control mass transfer zone was less than 15-30 cm for the operating conditions of these tests; (2) MERSORB carbon can sorb mercury up to 19 wt % of the carbon mass; and (3) the spent carbon retained almost all (98.3-99.99%) of the mercury during Toxicity Characteristic Leachability Procedure (TCLP) tests, but when even a small fraction of the total mercury dissolves, the spent carbon can fail the TCLP test when the spent carbon contains high mercury concentrations.