排序方式: 共有37条查询结果,搜索用时 31 毫秒
21.
PROBLEM: An average of three workers a year are killed in surface mining operations when a piece of haulage equipment collides with another smaller vehicle or a worker on foot. Another three workers are killed each year when haulage equipment backs over the edge of a dump point or stockpile. Devices to monitor the blind areas of mining equipment are needed to provide a warning to operators when a vehicle, person, or change in terrain is near the equipment. METHOD: A proximity warning system (PWS) based on the global positioning system (GPS) and peer-to-peer communication has been developed to prevent collisions between mining equipment, small vehicles, and stationary structures. RESULTS: A final system was demonstrated using one off-highway haul truck, three smaller vehicles, and various stationary structures at a surface mining operation. The system successfully displayed the location of nearby vehicles and stationary structures and provided visual and audible warnings to the equipment operator when they were within a preset distance. SUMMARY: Many surface mining operations already use GPS technology on their mobile equipment for tracking and dispatch. Our tests have shown that it is feasible to add proximity warning to these existing systems as a safety feature. Larger scale and long-term tests are needed to prove the technology adequately. IMPACT ON INDUSTRY: A PWSs that incorporates a combination of technologies could significantly reduce accidents that involve collisions or driving over an edge at surface mining operations. 相似文献
22.
The results of analyses for polychlorodibenzofuran (PCDF) content in two samples of polychlorobiphenyl (PCB) from used electrical transformers are presented and discussed. In neither sample was there evidence for enhanced PCDF concentrations even though one of them had been subjected to overheating while in service. 相似文献
23.
Results of analyses of eight samples of technical pentachlorophenol conducted by three different analytical methods are presented and discussed. 相似文献
24.
Nicholas M. Holden John F. Dowd Andrew G. Williams David Scholefield 《Environmental monitoring and assessment》1995,36(3):217-228
The use of chloride as a tracer for soil water investigations is discussed. Limitations with laboratory based soil core and field based sampling are considered with respect to the poor suitability of the data for rigorous assessment of mechanistic models. Investigation of water movement in soil has been restricted by limitations in spatial and temporal sampling. Fine resolution sampling generates large numbers of samples which cause problems with post sampling laboratory analysis. This paper describes a field-based system for the analysis of chloride in soil water. There are three component parts to the system, (i) a custom sampling sub-system comprising of ceramic cup suction samplers and sample traps, (ii) a sample routing sub-system to channel sample to (iii) a sample analysis sub-system utilizing a flow injection method for sample analysis using a custom built photo-diode detector. The three sub-systems were controlled by a suitably equipped personal computer. A calibration procedure is described with a third order polynomial equation derived to convert millivolt response from the detector into chloride concentration. Field and laboratory data from a tracer experiment are presented and discussed, and it is concluded that the system is well suited to field-based applications. Finally it is noted that the photo-detector is suitable for colourimetric analysis of any tracer with suitable chemical determination. 相似文献
25.
Malcolm S. Cresser Richard P. Smart Matthew Clark Andrew Crowe Danielle Holden Pippa J. Chapman Anthony C. Edwards 《Water, Air, & Soil Pollution: Focus》2004,4(6):85-95
Spatial and temporal changes in mobility of N species have been studied for three UK upland river networks, the Etherow in the South Pennines, the Nether Beck in the Lake District and the Dee in NE Scotland. The catchments are subject to N deposition at 35.1, 22.0 and 10.8–15.6 kg N ha–1 yr–1, respectively. TheNH
4
+
leaching appears to be predominantly regulated by flowpath in more polluted upland catchments. It is greatest where water draining acidified peaty soils contributes more to total discharge. Soluble organic matter may provide the dominant counter anion. In the Etherowand Dee catchments, which are dominated by acid mineral and organic soils, at high discharge NO
3
–
also appears to be associated with greater input of water from acidified soils. In contrast, for the Nether Beck, higher NO
3
–
concentrations are associated with tributaries draining soils contributingwater with higher alkalinity, suggesting nitrification is important. For the Etherow and Dee, dissolved organic N (DON) appears to originate predominantly from acidified, peaty soils. Spiking experiments with peat soil from the Etherow catchment confirmed the limited capacity of these soils to utilize inorganic N inputs, favouring equilibration with NH
4
+
inputs and leaching losses of inorganic N throughout the year. 相似文献
26.
A. Armstrong J. Holden P. Kay M. Foulger S. Gledhill A.T. McDonald A. Walker 《Journal of environmental management》2009,90(11):3512-3519
In recent years there has been a dramatic increase in artificial drain-blocking in world peatlands. The UK blanket peatlands have been severely drained over the past few decades but now drains are being blocked in an attempt to improve peatland environments. The drain-blocking has been a disparate process with limited knowledge transfer between organisations and within organisations operating in different geographic areas. Consequently, there has been no compilation of techniques used and their effectiveness. During this study thirty-two drain-blocked sites were surveyed and all the key stakeholders interviewed. Drain-blocking using peat turf was preferred by practitioners and was also the most cost-effective method. Peat turves were successful except on steep slopes, in areas of severe erosion, in very wet or very dry locations, or if the mineral substrate was exposed. A drain-blocking best practice guide is offered by this paper, providing information on the most suitable methods for blocking peatland drains under different circumstances. Additional considerations are provided for practitioners to ensure peatland drain-blocking is as successful as possible. 相似文献
27.
Joseph Holden Andy J. Howard L. Jared West Eleanor Maxfield Ian Panter John Oxley 《Journal of environmental management》2009,90(11):3197-3204
Environmental change caused by urban development, possibly augmented by climate change, may result in accelerated decay of in situ archaeological resources. Damage may be related to changes in hydrological processes. Such archaeological resources have to be considered in environmental planning. In this paper we highlight the need for improved hydrological data from urban archaeological sites using the case study of the City of York, UK, arguably one of the most well studied and well preserved urban archaeological environments globally. We suggest that the quality of hydrological data collected during routine surveys and experimental work must be improved and standardised in order for us to produce reliable archaeological risk models for urban sites. 相似文献
28.
Wood samples treated with technical pentachlorophenol (PCP), technical sodium pentachlorophenoxide (NaPCP) and octachlorodibenzo-p-dioxin have been exposed outdoors for periods up to years. Analysis of extracts from the samples show that photolytic reductive dechlorination of highly chlorinated dibenzo-p-dioxins to less chlorinated isomers occurs. However there is no discernible increase in polychlorodibenzo-p-dioxin concentrations in the technical PCP treated wood presumably because further photolytic reactions and volatilisation compete effectively with the photolytic formation. There is no evidence for formation of octachlorodibenzo-p-dioxin (OCDD) in technical PCP treated wood in this study, probably because photolytic destruction and volatilisation compete effectively with formation reactions when the initial OCDD concentration is relatively high. 相似文献
29.
30.
Alex G. Stewart Annie Worsley Vanessa Holden Andrew S. Hursthouse 《Environmental geochemistry and health》2012,34(6):653-664
The Society for Environmental Geochemistry and Health (SEGH) is a forum for multidisciplinary interaction relating the geochemical environment to health. With national funding, SEGH identified collaborative opportunities through the MULTITUDE series of workshops (2007–2011). We reviewed the meetings by electronic questionnaire (39?% response). Smaller meetings saw most returning delegates, suggesting networking and personal interaction is a key positive feature of SEGH; 31?% of practitioners and 25?% of academics participated in more than one meeting. Collaboration between SEGH participants resulted in joint funding (13 academics, 4 practitioners, 1 other) and joint papers (19, 5, 3). Evidence of behavioural change was seen in comments in five themes regarding the impacts of the conferences: support for current direction; impact on education practice (academics); new approaches; networking; multidisciplinary work. Multidisciplinary meetings and resulting networking were seen as having real value by many respondents, who encouraged further active pursuit of these activities. SEGH is eager to continue these activities which transform research, education and practice, resulting in a better understanding of the structure and processes comprising the broad geochemical environment on health. Comments showed the value and strength of small, well-organised conferences, bringing together a mixed group of disciplines, both research and applied, in a relaxed atmosphere. The absence of serious negative critique along with clear, positive comments suggests that there is a substantial level of support for, and even pleasure in, SEGH multidisciplinary conferences and workshops over the past years. It is encouraging that annual European conferences are viewed as such a positive achievement. 相似文献