现代过滤器清洁技术必须增加效益和避免环境问题

介绍了Schwing公司用于聚合物纺丝过滤系统组件的清洁工艺和设备,技术要点是采用水解或热解原理,具有增加效益和避免环境问题的优点。     

LIQUID-LIQUID EXTRACTION STUDIES OF METAL IONS WITH DIAZACROWN AND STRUCTURE ANALOGOUS OPEN-CHAIN COMPOUNOS

1,10-diaze [8]crown-6, their N,N'-dibutyl- and dioctyl-substituted derivatives and the structure analogous open-chein tetreoxedieza slkanee have been synthesized in order to examine the extraction properties for Na⁺, K⁺, Sr²⁺ and Hg²⁺. It wes found, that the extraction of strontium, potassium and sodium picratee with azacrown compounds ie much higher than that with open-chein oxaaze alkanes. 1,10-diaze [18] erown-6 has a good selectivity for the extraction of Sr²⁺ over K⁺ and Na in alkaline solution. In the case of Sr²⁺ the diffarencea between tha various azacrown compounds are email, whereea in the caee of K⁺ and Na the substituted derivativee are better extractante. Theserssulte correspond qualitativsly with tha order of stebility conetantB in protic solvsnts. The extrectebility of N,N'-dioctyl-l, 10-dieze[18]crown-6 for HgCl₂ is very high. Contrerv to the order of stability conetants the uneubetituted conpound do not extract mercury under the choeen experimental condition*. The extraction power of open-chain conpounde ie aleo high and strong Influenced by the alkyl eubatltuente at the nitrogen donor stons,     

Spatial scale and social impacts of biofuel production

The prospect of biofuels going ‘mainstream’ has drawn more attention to the social impacts of the production and use of transport biofuels. Since 2007, many media stories have appeared about alleged negative impacts of biofuels, notably the price of food going up or land-grab by plantation developers. These stories stand in stark contrast with the rosy picture painted by some academics involved in the technical development of bioethanol or biodiesel. This paper explores the questions when and why negative social impacts are likely to occur and under what circumstances more positive impacts might be expected. These impacts are discussed for three geographically defined biofuel supply chains; north-north, south-north and south-south. These three systems differ in the spatial scale of production and consumption and with that comes a different distribution of environmental, social and economic impacts. In the case of domestic production and consumption in developed countries, the social impacts are relatively minor and can be mitigated by social policies. Large scale, export-oriented production systems in developing countries could theoretically yield positive social impacts, but this would require on the one hand the tailored design of ‘pro-poor’ social innovations and interventions on the ground and on the other hand a certification of the supply chain feeding into consumer demand for ‘ethical’ fuel. The latent existence of this demand might be significant but recent NGO campaigns have severely undermined the ethical credentials of biofuels. It would require a persistent and collaborative effort to restore the brand value of ‘green’ fuel, an effort which will require better legislation and radically improved monitoring and enforcement practices in countries where the very absence of these has led to, and is still causing, the large scale destruction of habitats that are carbon sinks of global importance. The significant levels of government funding for biofuels stand in strong contrast with the problematic environmental and social governance of international biofuels supply chains. Notwithstanding the ‘must tackle climate change’ rhetoric by policy makers and in policy documents, this suggests that biofuels policy may be primarily driven by other concerns, especially regarding energy security. We argue that policies that are designed for a rather narrowly defined purpose of ‘security of supply’, cannot be realistically expected to yield high social or environmental benefits, and certainly not abroad.     

Building Large,Complex, Distributed Safety-Critical Operating Systems

Safety-critical systems typically operate in unpredictable environments. Requirements for safety and reliability are in conflict with those for real-time responsiveness. Due to unpredictable environmental needs there is no static trade-off between measures to accommodate the conflicting objectives. Instead every feature or operating system service has to be adaptive. Finally, for any design problem, there cannot be any closed-form (formal) approach taking care at the same time of (external) time constraints or deadlines, and synchronization requirements in distributed design. The reason is that these two aspects are causally independent. - In this situation we worked out a heuristic experimental, performance-driven and performance-based methodology that allows in an educated way to start with a coarse system model, with accurate logical expectations regarding its behavior. Through experiments these expectations are validated. If they are found to successfully stand the tests extended expectations and model features are generated for refining the previous design as well as its performance criteria. The refinement is done in such a way that the previous experimental configurations are extreme model cases or data profiles which both logically and experimentally are to reproduce the behavior of the previous modeling step. Thus the novel performance aspects or tendencies could then unambiguously be attributed to the influences of the refined model features. We termed this methodology Incremental Experimentation. As a general methodology it relies on a principle of comparative performance studies rather than on realistic data for narrow application ranges. The paper describes how we applied a 5-step design and refinement procedure for developing, analyzing, and evaluating our distributed operating system MELODY that exhibits novel services for supporting real-time and safety-critical applications in unpredictable environments. Experimental set-ups and theme-related findings are discussed in particular.     

Optically detected magnetic resonance of thiol-capped CdTe nanocrystals

The optical properties of thiol-stabilized CdTe nanocrystals have been examined. The thiol groups -SR generate a CdS shell at the interface, leading to a CdTe/CdS core—shell structure. The present paper describes our efforts to identify the influence of the CdTe–SR interface on the optical properties of the nanocrystals, utilizing photoluminescence and optically detected magnetic resonance (ODMR) spectroscopy. The photoluminescence spectrum consists of an excitonic peak, overlapped by a broad band at lower energies. The ODMR spectrum, in the spectral regime of the broad band, showed two resonance signals. They are associated with a trapped hole at an anisotropic site of a cadmium vacancy at the Cd–SR interface and an electron in the conduction band.     

Zur numerischen Simulation von Wärmenetzen

Forschung im Ingenieurwesen - Der Aufsatz beschreibt eine Möglichkeit, beliebig vermaschte Wärmenetze numerisch zu simulieren. Basierend auf einer graphentheoretischen Beschreibung der...     

Brain-computer communication: motivation, aim, and impact of exploring a virtual apartment.

The step away from a synchronized or cue-based brain-computer interface (BCI) and from laboratory conditions towards real world applications is very important and crucial in BCI research. This work shows that ten naive subjects can be trained in a synchronous paradigm within three sessions to navigate freely through a virtual apartment, whereby at every junction the subjects could decide by their own, how they wanted to explore the virtual environment (VE). This virtual apartment was designed similar to a real world application, with a goal-oriented task, a high mental workload, and a variable decision period for the subject. All subjects were able to perform long and stable motor imagery over a minimum time of 2 s. Using only three electroencephalogram (EEG) channels to analyze these imaginations, we were able to convert them into navigation commands. Additionally, it could be demonstrated that motivation is a very crucial factor in BCI research; motivated subjects perform much better than unmotivated ones.     

Development of intuitions about support beyond infancy.

In a series of 3 experiments modeled after infant studies, 3- to- 6-year-old children’s intuitive knowledge about support was assessed. Different objects were shown either sufficiently supported or not. Children had to predict whether a block would remain standing on a platform upon release or make perceptual judgments about the possibility of a shown block-on-platform configuration. Overall, performance was strongly age-related and independent of task context. Sensitivity for the amount of contact between object and support was clearly evidenced for each of the age-groups tested and was almost perfect in 5- and 6-year-olds. By contrast, sensitivity for the proportion of an object’s volume positioned over the support was only marginally reliable in 3-year-olds and still far from perfect in 6-year-olds. It is concluded that basic intuitions about support undergo distinct developmental change beyond infancy and are not yet fully developed in kindergartners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Five decades of Computer-Aided Ship Design

This article will present a synoptical review of key developments in Computer-Aided Ship Design since its inception about five decades ago. Milestone events and major innovations will be identified in several categories of ship design application with the principal emphasis on the methodologies, the modeling and the integration of the ship design process. The discussion will address many specific subtasks of ship design on the common platform of a human-guided, computer-based decision process.