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The relationship between light and perceived safety at night is intuitively strong, yet theoretically and empirically its workings are largely unknown. Intelligent dynamic road lighting, which continuously adapts to the presence and behavior of users, can light the street only when and where it is needed. As such, it offers a solution to the energy waste and luminous pollution associated with conventional road lighting. With this innovation, however, new questions emerge about the effect of lighting on perceived safety. We need to consider not only how much lighting pedestrians need to feel safe, but also which parts of the street should be lit. In two experiments, we investigated the effect of different light distributions on perceived safety, and explored mediation by people's appraisal of three safety-related cues suggested in the literature: prospect (having an overview), escape (perceived escape possibilities), and refuge/concealment (perceived hiding places for offenders). Both experiments, one with stationary and one with walking participants, demonstrated that people prefer having light in their own immediate surroundings rather than on the road that lies ahead. This could be explained, partially, by changes in prospect, escape, and concealment. Against expectations, prospect was higher with lighting distributions in which participants' immediate surroundings, but not the more distant parts of the road, were most strongly lit. 相似文献
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K Yoshida A Antal I Fuzesi L Nagy E Petro M Suzan 《Journal of environmental science and health. Part. B》1990,25(2):151-167
The technique of ultra-low volume by ultra-light aircraft for pesticide spray application has been discussed for some time in North America, mainly due to the air worthiness of such an aircraft which was not designed to carry appreciable amounts of payload. The risk factor of such application in insect control has not been determined, while applicator exposure to insecticide in ULV application by manual sprayer was assessed. An attempt was made to produce, by a series of field exposure measurements, a set of applicator exposure data for ULV-ULA and to compare the results with the data produced in synthetic pyrethroid application by using a hand-held ULV applicator. The applicator exposure of hand-held operation resulted in as high as 1000 times the exposure of aerial applicators indicating the effect of work practices and man-machine relationships. A delineation of toxic dose for these two types of applications shows that the aerial application could provide some benefits in reducing applicator exposure potential. 相似文献
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The increasing use of plastics in packaging materials leads to growing amounts of plastic waste. Recycling material is generally
regarded as advantageous. But in fact very few products are made from plastic waste, partly this can be explained by that
little is known about the recycling process and the properties of collected materials. There is a need for injection moulding
grades of recycled polyethylene, while large amounts of extrusion grades are available from packaging waste. A controlled
way of de-branching or partly degrading PE would be desirable. Peroxides are commonly used to crosslink polyolefins, but under
certain conditions a chain scission reaction occur. Another problem encountered with recycling of polyethylene are the poor
miscibility of low amounts contaminations, i. e. polypropylene. A compatibilizer can improve properties of such polymer blends,
in this work EPDM is used as compatibilzer. Studies of mechanical properties and viscosity measurements show that it is possible
to partly degrade PE with peroxide exposing it to high temperature and oxygen. The properties of PE/PP blends were improved
with EPDM as compatibilizer. 相似文献
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Sandra Tostar Erik Stenvall Antal Boldizar Mark R. St. J. Foreman 《Waste management (New York, N.Y.)》2013,33(6):1478-1482
There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5 M) dissolved in either dimethyl sulfoxide or water (at ca. 23 °C and heated to ca. 105 °C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed. 相似文献
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Erik Stenvall Sandra Tostar Antal Boldizar Mark R.StJ. Foreman Kenneth Möller 《Waste management (New York, N.Y.)》2013,33(4):915-922
The compositions of three WEEE plastic batches of different origin were investigated using infrared spectroscopy, and the metal content was determined with inductively coupled plasma. The composition analysis of the plastics was based mainly on 14 samples collected from a real waste stream, and showed that the major constituents were high impact polystyrene (42 wt%), acrylonitrile–butadiene–styrene copolymer (38 wt%) and polypropylene (10 wt%). Their respective standard deviations were 21.4%, 16.5% and 60.7%, indicating a considerable variation even within a single batch. The level of metal particle contamination was found to be low in all samples, whereas wood contamination and rubber contamination were found to be about 1 wt% each in most samples. In the metal content analysis, iron was detected at levels up to 700 ppm in the recyclable waste plastics fraction, which is of concern due to its potential to catalyse redox reactions during melt processing and thus accelerate the degradation of plastics during recycling. Toxic metals were found only at very low concentrations, with the exception of lead and cadmium which could be detected at 200 ppm and 70 ppm levels, respectively, but these values are below the current threshold limits of 1000 ppm and 100 ppm set by the Restriction of Hazardous Substances directive. 相似文献
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Marguerite Miguet Julien Thevenon Vincent Laugel Mathilde Lefebvre Aurélie Bourchany Jean-Baptiste Rivière Yannis Duffourd Elise Schaefer Maria Cristina Antal Rosalie Abida Anne-Sophie Weingertner Valérie Kremer Pierre Vabres Fanny Morice-Picard Marie Gonzales Dan Lipsker Sylvie Fraitag Jean-Louis Mandel Jamel Chelly Hélène Dollfus Laurence Faivre Christel Thauvin-Robinet Nadège Calmels Salima El Chehadeh 《黑龙江环境通报》2016,36(13):1276-1279
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