排序方式: 共有7条查询结果,搜索用时 15 毫秒
1
1.
Formation pathways of polychlorinated dibenzofurans (PCDFs) in sediments contaminated with PCBs during the thermal desorption process 总被引:1,自引:0,他引:1
Thermal desorption has attracted considerable interest as a remediation technology for the removal of dioxins and polychlorinated biphenyls (PCBs) from contaminated soils and sediments. Although several research groups have confirmed that polychlorinated dibenzofurans (PCDFs) are formed from PCBs during the thermal desorption of sediments contaminated with PCB, the formation pathways remain poorly understood. Herein, thermal desorption has been used to develop a greater understanding of the formation pathways of PCDFs from sediments contaminated with PCBs. PCB decomposition experiments of sediments contaminated with PCBs were performed over 5 min at 450 °C with a gas composition of 10% O(2)/90% N(2), either in the absence (Run 1) or presence (Run 2-4) of one of three different (13)C(12)-labeled PCB individual standards. The results of Run 1 showed that 99.96% of PCBs and 98.40% of polychlorinated dibenzo-p-dioxins (PCDDs) in the treated sediments had decomposed, whereas the concentration levels of PCDFs had increased by a factor of 31. The addition of different (13)C(12)-labeled PCBs to the sediment sample yielded different (13)C(12)-PCDFs isomer patterns, with formation pathways including loss of ortho-Cl(2), loss of HCl involving a 2,3-chlorine shift, loss of ortho-H(2) and dechlorination. 相似文献
2.
I. Nishiumi Satoshi Yamagishi Hiromi Maekawa Chikashi Shimoda 《Behavioral ecology and sociobiology》1996,39(4):211-217
In many polygynous animals, parents invest more heavily in individual sons than in daughters. However, it is unclear if these
differences in investment are a consequence of sex differences in the demand of offspring related to sexual size dimorphism
or a consequence of parental manipulation. Here, we report on parental food delivery frequency in relation to brood size and
brood sex ratio in a wild population of polygynous great reed warblers Acrocephalus arundinaceus. We used the polymorphic microsatellite loci on the Z chromosome to sex chicks. We found that paternal feeding frequency
(times/h per nest) increased not with brood size, but with the proportion of males in the brood, although the demand per nest
was more closely related to brood size than to brood sex ratio. Additionally, the increase in rate of paternal feeding frequency
in relation to the brood sex ratio was much higher than the increase in rate of nestling food demands. Maternal feeding frequency
was independent of both brood size and brood sex ratio. These results strongly suggest that fathers preferentially invest
in their sons. We propose that parents can afford sex-biased parental care in animals in which food provisioning is enough
for all offspring to survive.
Received: 22 January 1996/Accepted after revision: 30 June 1996 相似文献
3.
Kosugi Takanobu Shimoda Yoshiyuki Tashiro Takayuki 《Environmental Economics and Policy Studies》2019,21(4):477-505
Environmental Economics and Policy Studies - This study investigates the factors influencing the diffusion of residential photovoltaic systems. Factors examined are related to social attributes,... 相似文献
4.
Daisuke Narumi Akira Kondo Yoshiyuki Shimoda 《Atmospheric environment (Oxford, England : 1994)》2009,43(14):2348-2359
An atmospheric dispersion model, where the inputs of meteorological field were calculated using a meteorological model, was used to reproduce the observed air pollution conditions for the typical fine day in summer period, especially the concentration of the photochemical oxidants. As well, the effects of an increase in the urban temperature and VOC emissions on the concentration of photochemical oxidants were also considered. The following conclusions were drawn.The observed air pollution levels were well modeled by the atmospheric dispersion model using in this study, although modeled NO levels were slightly lower than the observed levels. An analysis of the temperature data showed that a 1 °C increase in temperature leads to a maximal photochemical oxidant concentration of 5.3 ppb, which is an increase of 11%. Additionally, the effect on the photochemical oxidant concentration due to an increase in the vegetation-derived VOCs was more than double the effect due to an increase in the photochemical reactions. It was found that the temperature and photochemical oxidant concentration were linearly related up to a temperature increase of 3 °C. When the temperature increases up to 3 °C, the concentration of photochemical oxidants increases by 19 ppb. An analysis of the effect of vegetation-derived VOCs on photochemical oxidant concentrations showed that, the concentration of photochemical oxidants was 30 ppb higher in the afternoon by the effect of vegetation-derived VOCs, so even in metropolitan areas with relatively little vegetation, vegetation-derived VOCs have a strong impact on photochemical oxidant concentrations. 相似文献
5.
Steven Shimoda H.William Prengle Jr James M. Symons 《Waste management (New York, N.Y.)》1997,17(8):507-515
This paper presents the chemical reaction engineering development of the H2O2/VisUV photo-oxidation process for treatment of hazardous waterborne substances, that occur in groundwater, leachates, and industrial wastewater. Reaction results, on benzene (BNZ), dichlorobenzene (DCB), trichloroethene (TCE), trichloroethane (TCA), and carbon tetrachloride (CTC), have been obtained, providing engineering data and models that can be used to size full-scale equipment. A photochemical flow stirred tank reactor (pcfSTR) and a photo-chemical tubular flow reactor (pcTFR) were used in the experimental work. Two experimental discoveries were made in the course of the work: (1) conventional thermal kinetics do not apply, the rate controlling variable is the photon flux, and (2) for the photo-chemical reactors used, the pcfSTR was more effective than the pcTFR. The following sub-topics are discussed: reaction mechanism, reactor hydrodynamics, photon flux effects, typical reaction data (on benzene and trichloroethane), and rate constants. 相似文献
6.
7.
Educational initiative of Osaka University in sustainability science: mobilizing science and technology towards sustainability 总被引:1,自引:1,他引:0
Michinori Uwasu Helmut Yabar Keishiro Hara Yoshiyuki Shimoda Tatsuyoshi Saijo 《Sustainability Science》2009,4(1):45-53
One of the most important and yet difficult challenges that modern societies face is how to mobilize science and technology
(S&T) to minimize the impact of human activities on the Earth’s life support systems. As the establishment of inter-disciplinary
education programs is necessary to design a unified vision towards understanding the complexity of human nature, the Research
Institute for Sustainability Science (RISS) launched a new program on sustainability science in April 2008. The program expects
to address the issue of how to use knowledge more effectively to understand the dynamic interactions between nature and human
society. This paper first offers an overview of international and Japanese initiatives on sustainability education in which
we highlight the uniqueness of the attempt by the Integrated Research System for Sustainability Science (IR3S). The paper
then introduces the RISS program for sustainability science, addressing the principles and curriculum design of the program.
The paper discusses the main problems and constraints faced when developing the program, such as institutional barriers in
building a curriculum and obtaining cooperation from faculty. To challenge these barriers and limitations, the RISS uses the
program as a platform to disseminate the idea of sustainability science across the university. This attempt helps us to obtain
the continuing cooperation necessary to improve and maintain the program.
相似文献
Michinori UwasuEmail: |
1