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匹配条件: “Daniel W.S. Challender” ,找到相关结果约411597条。
Wildlife trade in Asia: start with the consumer
Diogo Veríssimo,Daniel W.S. Challender,Vincent Nijman
Asian Journal of Conservation Biology , 2012,
The reliability analysis of cutting tools in the HSM processes
W.S. Lin
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: This article mainly describe the reliability of the cutting tools in the high speed turning by normaldistribution model.Design/methodology/approach: A series of experimental tests have been done to evaluate the reliabilityvariation of the cutting tools. From experimental results, the tool wear distribution and the tool life are determined,and the tool life distribution and the reliability function of cutting tools are derived. Further, the reliability ofcutting tools at anytime for high speed machining (HSM) is easily calculated from cutting parameters and toolwear limit from the derived reliability function.Findings: The higher the cutting speed, the sooner the tool flank wear, and the faster the degrade speed of thereliability curve. It means that the sooner the tool flank wear rate, the shorter the tool life, and it is the time tochange the cutting tool.Practical implications: This paper shows that the tool flank wear rate can be described by the reliabilitydegrade rate, the higher the flank wear rate, the steeper the tool reliability degrade rate.Originality/value: This article is discussing about the tool wear variation of the cutting tool from the point ofreliability. From the reliability variation of the cutting tool, we can further predict the tool life, in order to decidethe tool replacement time.
The study of high speed fine turning of austenitic stainless steel
W.S. Lin
Journal of Achievements in Materials and Manufacturing Engineering , 2008,
Abstract: Purpose: The purpose of this research paper is focused on the surface roughness variation in high speed fine turning of the austenitic stainless steel.Design/methodology/approach: A series of experimental tests have been done to evaluate the possibility of high speed fine turning of the austenitic stainless steel from the surface roughness variation and machining stability.Findings: It was found that, the smaller the feed rate, the smaller the surface roughness value. But when the feed rate smaller than the critical feed rate, the chatter will occurs and the surface roughness of the work piece would be deteriorated.The higher the cutting speed is, the higher the cutting temperature of cutting tool is. The cutting tool will be soften and the surface roughness of the workpiece will be deteriorated.Research limitations/implications: The tool chattering would caused poor surface roughness in high speed fine turning for feed rate smaller than 0.02 mm/rev. The chatter suppression method must be considered when high speed fine turning of austenitic stainless steel.Originality/value: Most of the stainless steel machining proceeds at low cutting speed because the austenitic stainless steel is a hard machining material. The research result of this paper indicated that high speed fine turning of austenitic stainless steel is possible.
MgO-Au cermet films
Gold Bulletin , 1978, DOI: 10.1007/BF03216527
The development of gold drugs
Gold Bulletin , 1981, DOI: 10.1007/BF03216736
Precipitation hardening and ordering of carat gold jewellery alloys
Gold Bulletin , 1978, DOI: 10.1007/BF03216531
Abstract: The mechanical properties of gold jewellery alloys are dependant upon their thermal as well as their mechanical histories. An understanding of the mechanisms by which they harden during thermal treatment is therefore important. Two contributions to knowledge in this area are discussed in this note.
Fire regime of the Kruger National Park for the period 1980 -1992
W.S.W. Trollope
Koedoe : African Protected Area Conservation and Science , 1993, DOI: 10.4102/koedoe.v36i2.373
Abstract: Fire regime refers to the type and intensity of fire and the season and frequency of burning. In the Kruger National Park it varies according to the source of ignition of the fires. Since 1985 the different ignition sources have been controlled bums (47), refugees (23), others (20) and lightning (10). The data showed that anthropogenic fires were the most common fires and evidence on a global scale would suggest that the status quo will be maintained even if controlled burning is discontinued as is currently being considered by the National Parks Board. The most common type of fires that occur in the park are surface head fires burning with the wind but back fires and crown fires do also occur. The intensity of the fires is primarily a function of the grass fuel load which is dependent on the rainfall and consequently varies enormously from year to year. The type of fire also influences the intensity and research conducted during 1992 showed that head fires burning under similar environmental conditions were on average 36 times more intense than back fires. Anthropogenic fires generally occurred during the dry, dormant, winter period while lightning fires were more associated with the spring and summer period when dry lightning storms occur. The frequency of burning varied significantly between sourveld and sweetveld. The mean frequency of burning in sourveld areas was triennial and in the sweetveld areas octennial. Finally the general conclusion that can be drawn about the fire regime of the Kruger National Park is that it is highly variable and will continue to be so in the future. This is a very positive feature that ensures a wide diversity of habitat types.
Veld management with specific reference to game ranching in the grassland and savanna areas of South Africa
W.S.W. Trollope
Koedoe : African Protected Area Conservation and Science , 1990, DOI: 10.4102/koedoe.v33i2.443
Abstract: Veld management refers to the management of natural vegetation for specific objectives related to different forms of land use. In the wildlife context a wide spectrum of different forms of land use are practised ranging from pure nature conservation in large national parks through to smaller areas used for game farming. Consequently the products useable to society emanating from these areas vary greatly, and therefore the management of veld stocked with wildlife is extremely complex and must be adapted to the particular form of land use that is being practised. A generally accepted principle is that the smaller the area being used for wildlife the more intensively it must be managed, particularly game ranches. A prerequisite for the development of an effective veld management program is a comprehensive assessment of the condition of the veld upon which realistic veld management practices can be formulated. These practices will include stocking the veld with the appropriate species and numbers of animals, grazing and browsing management, veld burning and the provision of watering points. Finally a programme for monitoring veld condition over time is a prerequisite for sound veld management.
汉景泰,W.S. Fyfe
科学通报 , 2000,
Abstract: 以铁的硫化物矿折黄铁矿和磁黄铁矿为吸附材料,在实验室条件下研究了它们对模型水体中的砷的吸附作用。在实验观测基础上讨论了这些矿物材料对砷的吸附速率和效率,吸附砷的稳定性以及稳定条件,提出这些矿物去除水体中砷的有效吸附材料,对于缺乏水质处理设备条件的地区有直接的实用价值。
Culture of Pangasianodon hypophthalmus into India: Impacts and Present Scenario
A. K. Singh,W.S. Lakra
Pakistan Journal of Biological Sciences , 2012,
Abstract: Pangasianodon aquaculture is the fastest growing food producing sector of the world. Recent national production of Pangasianodon hypophthalmus in India accounts for 0.7 million tonnes at present. Being influenced by trade and markets, P. hypophthalmus has been introduced to many countries including India. There has been a steady increase in the production of P. hypophthalmus by small and marginal farmers of the country. However, concern has arisen about the long term sustainability due to diseases and its negative impacts on socio-economic aspects and biodiversity. Unregulated culture of P. hypophthalmus has been causing concern to environmental safety and warranting a very cautious and regulated approach to its culture. The standards, protocols and guidelines have been developed to address the issues of sustainability of Pangasianodon catfish production.

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