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781.
《Environmental engineering science》2011,28(11):775-779
Abstract An increasing demand for bio-based vehicle fuels and impending harsher regulations of CO2 emissions are driving the development of a second generation of ethanol fuel processes. These processes will increase yields and make new feedstocks available, as they are designed to handle lignocellulosic materials such as wood. In order to achieve a sound financial economy of such a process, as well as an acceptable degree of energy efficiency, it is of the utmost importance that the lignin produced has a high dry content. An experimental study was conducted on lignin slurry from a pilot plant in the north of Sweden, in which the lignin slurry was filtered, pressed, and characterized. The dewatering was evaluated with the classical filtration equation by determining the average specific filtration resistance of the filter cakes. Compared with previous work, relatively low values of the specific filtration resistance were obtained. It is probable that the low values were an effect of the high amount of cel... 相似文献
782.
Lars Hendrik Simon Volker Wilkens Thomas Fedtke Michael Beyer 《Journal of Loss Prevention in the Process Industries》2013,26(6):1583-1589
This paper shows the results of our investigations on the ignition source ultrasound in dust-air atmospheres. Ultrasound is, on the one hand, considered to be an ignition source according to international safety standards (EN 1127–1 (2011)). On the other hand, though, ultrasound is used for various applications in gases and air, such as level and flow measurement, or in the process industry, but no explosion accidents have yet been reported. Our research now shows that it is indeed possible to ignite dust-air mixtures in ultrasound fields under certain conditions. We conducted our experiments in an ultrasound standing wave field and used maize starch, calcium stearate and sulfur dust. For ignitions, an absorbing target was needed to convert the acoustic energy into heat. From theoretical estimations and experiments critical conditions that provoke ultrasonically triggered explosions are identified. 相似文献
783.
Monique Lortie Geneviève Baril-Gingras 《International journal of occupational safety and ergonomics》2013,19(1):3-18
The handling of 2,306 boxes being loaded or unloaded from vans onto or from 4-wheeled trolleys by 31 handlers in a warehouse were characterized. Handling was videotaped and characterized through an analysis grid completed by three trained observers. The following execution parameters were observed: nature of the exertion applied by the upper limbs, plane and direction of the exertion, resulting displacement of the box, grip, use of the lower limbs and the back. Results show that execution parameters used by handlers vary considerably from those usually recommended or studied. For example, symmetric grips were rarely used (4%). The grip was modified during the handling of half the boxes. Significant knee flexion was rarely observed (3% of exertions). Each box was moved by applying an average of . 3.5 different exertions. Exertions were mostly applied in a plane parallel to the shoulders; they were rarely executed in a strict sagittal plane (11%). The implication of these observations are discussed. 相似文献
784.
人工模拟环境试验中气候环境试验的条件是否真实,主要取决于环境试验设备技术性能指标,主要包括温度偏差、温度均匀度、温度波动度.由于测试点较多,在数据处理及结果不确定度评定上工作量较大,因此使用EXCEL数据处理软件进行计算,一方面保证了数据准确可靠,另一方面提高了工作效率. 相似文献
785.
786.
A FRAMEWORK FOR PROCESS INDICATORS TO MONITOR
FOR SUSTAINABLE DEVELOPMENT: PRACTICE TO AN URBAN WATER SYSTEM 总被引:2,自引:0,他引:2
Although very often used, the concept of sustainable development has not yet been perceived pragmatically. Due to its process
nature, in this paper, we argue that sustainable development is a process in which the essential feedback loops, or Viability Loops as we name them, in the system in question are kept healthy and functional. This process deals with evolutionary changes
with the end point not known in advance. According to this perception, measurement of sustainable development does not make
sense. Rather, we should look for the process indicators to monitor systems for sustainable development. The purpose of the
paper is to develop a methodology to deal with monitoring systems for sustainable development and its practice in an urban
water system. Using a system dynamics approach, the paper adopts a systemic monitoring framework based on the idea of Viability Loops to define process indicators to monitor systems for sustainable development. To illustrate the application of the framework,
its practice in the urban water system of Tehran, the capital of Iran, is provided as an example. The example of the urban
water supply system of Tehran is given as a case study, albeit with some unavailable data. Here, four typical viability loops
are discussed. The results of this application show that the flows of informative signals are lacking. Adopting the process
indicators, we can see the gaps between the public perceptions of water abundance, the costs of water provision and energy
utilizations, and what is going on in the reality are getting wider. That indicates that the viability loops are not functional
enough to produce effective changes to offset the reinforcing mechanisms. The sustainable development of the system is impaired
due to the persistence of those reinforcing mechanisms. 相似文献
787.
E. L. Genikhovich I. G. Gracheva R. I. Onikul E. N. Filatova 《Water, Air, & Soil Pollution: Focus》2002,2(5-6):501-512
Urban concentration fields are extremely inhomogeneous andtheir gradients are very high. It results in specificproblems when modelling air pollution at the urban scalethat are analysed in this paper. Some examples ofmisrepresentation of the urban concentration field,computed with the use of the source-receptor type models,are given here. They can help in understanding the natureof the problems we face and reveal deficiencies of thecomputational technologies in use. Filtering of thecomputed fields is suggested as an instrument for improvingtheir quality. Its efficiency is proved on the test runs.An algorithm for refinement of the filtered fields isintroduced in this paper. 相似文献
788.
在声学研究分析的基础上,阐述了内燃机噪声测试室的工程设计要点,论证了噪声测试室与试车室共用的可行性。 相似文献
789.
贵阳地区氡浓度的连续观测 总被引:1,自引:0,他引:1
叙述用静电累积氡测量仪对贵阳地区环境氡浓度进行连续四年的观测,氡浓度季节性的变化受气温、降雨量等因素的影响较大,降雨不仅可使环境氡浓度降低,而且在降雨量相近的情况下降雨次数较多氡浓度也会相对偏低。 相似文献
790.
The Wild Animal as a Research Animal 总被引:1,自引:0,他引:1
Jac. A.A. Swart 《Journal of Agricultural and Environmental Ethics》2004,17(2):181-197
Most discussions on animal experimentation refer to domesticated animals and regulations are tailored to this class of animals. However, wild animals are also used for research, e.g., in biological field research that is often directed to fundamental ecological-evolutionary questions or to conservation goals. There are several differences between domesticated and wild animals that are relevant for evaluation of the acceptability of animal experiments. Biological features of wild animals are often more critical as compared with domesticated animals because of their survival effects. An important issue is what is called here “natural suffering”: the suffering from natural circumstances. Should this type of suffering be taken into account when suffering from experimentation is evaluated? As an answer, it is suggested that ``natural functioning'' should be considered as an additional standard in the evaluation of wild animal experimentation. Finally, two topics related to the ecological context are considered. Firstly, the often inevitable involvement of non-research animals in wild animal experimentation, and secondly, the eco-centric approach to nature conservation. According to the latter position, animals are subordinated to ecosystems. All these aspects make the evaluation of wild animal experiments much more complex than experiments with domesticated animals. Preliminary scores are proposed to deal with these aspects. It is argued that this should not lead to a more complex governmental regulation, since an effective maintenance and control are hard to realize and one may loose the cooperation of researchers themselves. In addition, non-governmental professional organizations such as research societies and funding organizations play a pivotal role. 相似文献