Estimating the Recreation Demand and Economic Value of Mountain Biking in Moab,Utah: An Application of Count Data Models

This paper reports the results of both standard and truncated count data travel cost demand models for estimating demand for and the economic value to participants in mountain biking in the Moab, Utah, area. The empirical estimates for average trip demand per person per season were 2.25 and 2.53 trips under truncated Poisson and truncated negative binomial models, respectively. Consumer surplus per person per trip for both models was approximately US $585. The total annual use value for mountain biking in the Moab area was US $1.33 million. This value suggests that this recreation has a higher value than most other activities in the area and that public land managers should be aware of the relative value of mountain biking as they make allocation decisions.     

Factors Determining the Post-consumer Waste Recycling Burden

The environmental burden of collecting recoverables from households is generally omitted from life-cycle analyses comparing the environmental outcome of using secondary material from post-consumer waste (PCW) with virgin feedstock. However, this burden can be considerable, depending upon the characteristics of the collection methods employed. Given that the basic objective of recycling is to secure environmental benefits, it is vital that the burden of collection through both bring/dropoff and kerbside schemes is taken into account if a valid assessment of the environmental balance resulting from PCW recycling is to be made. This paper presents survey data comparing the burden of collection for different types of recycling provision. It describes the site and spatial characteristics determining the amount of transport dedicated to collection at bring/drop-off sites. Predictor variables are identified as measures of these characteristics, and the survey data compared with them. A regression model to assess energy use at bring/drop-off sites with varying characteristics is then developed. The potential uses of the techniques presented include the evaluation of the environmental burdens of recycling provision at the waste collection authority and regional level, allowing more informed choices to be made in the development of recycling provision from an environmental standpoint.     

可持续性与生命科学产业

生物技术是1980年代和1990年代初作为推动一场新农业革命的技术而提出来的.若干家大型化学公司作为“生命科学”公司的再发明旨在探讨这种新知识和寄希望于正在展开的遗传学革命.这种范例转变在某些地区、尤其北美已经开始展开,但在其它地区、尤其欧洲似乎弄得十分糟糕.如同在它之前的几个产业一样,生命科学产业已经无法把利害攸关者的关注充分融入其战略性决策中.这一失败,加上其它因素例如对法规部门和多国公司的日益不信任,意味着这项新技术是在日益充满敌意的环境中推出的.     

LNG trench dispersion modeling using computational fluid dynamics

Quantifying the size of flammable vapor cloud hazards associated with an accidental release of Liquefied Natural Gas (LNG) into a spill containment system supported by narrow drainage trenches has posed a modeling challenge since the inception of the LNG industry. Early attempts to treat the vapors evolving from the trenches included using line-source Gaussian models, and the use of the DEGADIS model by modeling “segmented” trench elements and adding the contributions from each trench segment at a specified downwind distance. These approaches often are only reasonable for a select set of conditions (e.g., winds perpendicular to the trench) and have no ability to simulate many of the conditions that might result in a larger potential impact (e.g., winds blowing parallel to the trench).     

Retrofit NO x Control Options

Modifications to the combustion process have been the basis for NO_x control on new coal-fired power plants to meet federal New Source Performance Standards (NSPS) Promulgated in 1971 and revised in 1978. In the event that retrofit NO_x control is required on pre-NSPS plants, low-NO_x combustion will likely be the least cost approach, if such controls can be successfully applied to the wide diversity of these older utility boiler designs now in operation. A series of retrofit low-NOx combustion demonstrations supported by EPRI and electric utility companies are intended to establish the technical and economic feasibility of this approach.     

The environment and technical education in the united kingdom

Summary In showing that substantially more than three-quarters of the population of England and Wales at some stage in their career receive education or training in the further education sector, the author advocates the case for environmental education to be extensively developed at this educational level. An expanded programme in technical and allied colleges should contain elements of environmental education for nearly all technicians as well as specialist full-time training schemes for persons such as environmental monitoring technicians.Dr John F. Potter has been Hon. Secretary of the Institution of Environmental Sciences (UK) over the last five years. He is Editor of that Institution's News Sheet and Proceedings as well as being one of the General Editors of the IES/Wiley Environment Monograph Series. Trained as a geologist at the Universities of Manchester and London, he is currently Principal of Farnborough College of Technology, Hampshire, UK, where he has overall responsibility for a large number of educational programmes, many of which are concerned with the development of skills required by technicians and technologists.