Optimization of tank and flat-plate collector of solar water heating system for single-family households to assure economic efficiency through the TRNSYS program

Solar water heating systems are widely used in Brazil for domestic purposes in single-family households. The exploitation of the potential energy of the water from the upper tank and the thermosyphon phenomena for hot water circulation constitutes the absolute majority of the residential solar water heating systems in the country. But, these water heating systems are usually sized according to tables provided by the manufacturers, which show the number of plates required based on the size of the family and the number of hot water outlets. This sizing is based much more on intuition rather than on scientific data. For that reason, this work has developed an optimization model for water heating systems design parameters, using a numerical simulation routine, in a long-term transient regime. The optimized design gives the slope and area of the flat plate collector, which results in the minimum cost over the equipment life cycle. The computing procedure was executed considering specific characteristics of the project. A thermosyphon solar water heating system with flat-plate collector for Sao Paulo's climate was simulated. The practice of Brazilian designers and manufacturers is to recommend the maximization of the energetic gain for the winter. This paper has analyzed in economic terms if it is more attractive to increase the gain of solar energy in the winter period, with the consequence of reduction of the solar energy gain along the year, or to adopt the adequate slope, which improves the yearly solar energy gain.     

Changes in field potentials and membrane currents in rat sensorimotor cortex following repeated tetanization of the corpus callosum in vivo

Repeated, daily tetanization of the corpus callosum induces lasting changes in sensorimotor cortex field potential responses, but the synaptic populations that mediate these responses and support long-term potentiation (LTP) have not been characterized. Current source density analyses of field responses were compared between control animals and those in which LTP was induced by 10 daily series of tetanizations. Tetanization and paired-pulse stimulation (100 ms interval) enhanced the duration of initial (approximately 3 ms onset) deep-negative population spike activity generated by a current sink in layer V that peaked repeatedly at a frequency of approximately 400 Hz. The early (approximately 10 ms to peak) surface-negative component of field responses was generated by a current sink in upper layer V and a source in layer VI. This monosynaptic component followed high stimulation frequencies, recovered quickly from the effects of anaesthesia, and was enhanced by both tetanization and paired-pulse stimulation. The late (approximately 20 ms to peak) surface-negative component was generated by a sink in upper layer V and a source deep in layer V, and was greatly enhanced by tetanization and paired-pulse stimulation. The late component did not follow high-frequency stimulation and recovered slowly from anaesthesia, suggesting that it is driven polysynaptically. Potentiation of monosynaptic thalamic and cortico-cortical afferents probably mediates enhancements of the early component and population spikes, while potentiation of polysynaptic afferents to layer V may contribute to growth in the late component.     

Le co?t de l'effacement du schwa lors de la reconnaissance des mots en fran?ais.

We studied the processing of two word strings in French made up of a determiner and a noun which contains a schwa (mute e). Depending on the noun, schwa deletion is present, optional or absent. In a production study, we show that schwa deletion, and the category of the noun, have a large impact on the duration of the strings. We take this into account in two perception studies, which use word repetition and lexical decision, and which show that words in which the schwa has been deleted usually take longer to recognize than words that retain the schwa, but that this depends also on the category of the word. We explain these results by examining the influence of orthography. Based on the model proposed by Grainger and Ferrand (1996), which integrates the written dimension, we suggest that two sources of information, phonological and orthographic, interact during spoken word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Redundancy detection in semistructured case bases

With the dramatic proliferation of case-based reasoning systems in commercial applications, many case bases are now becoming legacy systems. They represent a significant portion of an organization's assets, but they are large and difficult to maintain. One of the contributing factors is that these case bases are often large and yet unstructured or semistructured; they are represented in natural language text. Adding to the complexity is the fact that the case bases are often authored and updated by different people from a variety of knowledge sources, making it highly likely for a case base to contain redundant and inconsistent knowledge. We present methods and a system for maintaining large and semistructured case bases. We focus on a difficult problem in case base maintenance: redundancy detection. This problem is particularly pervasive when one deals with a semistructured case base. We discuss an information retrieval-based algorithm and an implemented system for solving this problem. As the ability to contain the knowledge acquisition problem is of paramount importance, our method allows one to express relevant domain expertise for detecting redundancy naturally and effortlessly. Empirical evaluations of the system demonstrate the effectiveness of the methods in several large domains     

On the ambiguity of concept use in commentaries.

In this article, we respond in general and specific terms to the commentaries written on our target article (Slaney & Racine, 2011). In so doing, we revisit the motivation for our initial article and attempt to clarify certain aspects of our argument. Given that we were taken by some to be trying to undermine the Representational Theory of Mind (RTM), we discuss RTM in some detail. We also discuss Wittgenstein's methods and their relevance to the issues raised in our article and in the commentaries. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

PON OTDR仪表介绍

PON拓扑在许多方面与传统网络不同,当使用OTDR测试链路特性时面临新的挑战.能够用于测试PON的OTDR的特征包括能够利用相对短的脉冲、灵敏的光学检测电路和优化的软件分析提供足够大的动态范围.     

Fabrication and characterization of cantilevers with integrated sharp tips and piezoelectric elements for actuation and detection for parallel AFM applications

We have developed a new process to fabricate arrays of cantilevers with integrated tips for atomic force microscope (AFM) imaging and a piezoelectric layer for vertical actuation and detection. A good homogeneity of the tip shape is obtained thanks to a self-sharpening effect. The cantilevers have been characterized mechanically and electrically.     

Nephrotoxic Potential of Putative 3,5-Dichloroaniline (3,5-DCA) Metabolites and Biotransformation of 3,5-DCA in Isolated Kidney Cells from Fischer 344 Rats

The current study was designed to explore the in vitro nephrotoxic potential of four 3,5-dichloroaniline (3,5-DCA) metabolites (3,5-dichloroacetanilide, 3,5-DCAA; 3,5-dichlorophenylhydroxylamine, 3,5-DCPHA; 2-amino-4,6-dichlorophenol, 2-A-4,6-DCP; 3,5-dichloronitrobenzene, 3,5-DCNB) and to determine the renal metabolism of 3,5-DCA in vitro. In cytotoxicity testing, isolated kidney cells (IKC) from male Fischer 344 rats (~4 million/mL, 3 mL) were exposed to a metabolite (0–1.5 mM; up to 90 min) or vehicle. Of these metabolites, 3,5-DCPHA was the most potent nephrotoxicant, with 3,5-DCNB intermediate in nephrotoxic potential. 2-A-4,6-DCP and 3,5-DCAA were not cytotoxic. In separate experiments, 3,5-DCNB cytotoxicity was reduced by pretreating IKC with antioxidants and cytochrome P450, flavin monooxygenase and peroxidase inhibitors, while 3,5-DCPHA cytotoxicity was attenuated by two nucleophilic antioxidants (glutathione and N-acetyl-L-cysteine). Incubation of IKC with 3,5-DCA (0.5–1.0 mM, 90 min) produced only 3,5-DCAA and 3,5-DCNB as detectable metabolites. These data suggest that 3,5-DCNB and 3,5-DCPHA are potential nephrotoxic metabolites and may contribute to 3,5-DCA induced nephrotoxicity in vivo. In addition, the kidney can bioactivate 3,5-DCNB to toxic metabolites, and 3,5-DCPHA appears to generate reactive metabolites to contribute to 3,5-DCA nephrotoxicity. In vitro, N-oxidation of 3,5-DCA appears to be the primary mechanism of bioactivation of 3,5-DCA to nephrotoxic metabolites.     

Hybrid ultrasonic elastic force motors micromachined in silicon

Abstract

A micromotor for low power applications is being developed using silicon micromachining technologies and organometallic PZT films sol-gel deposition. The construction of a hybrid ultrasonic motor suitable for batch fabrication is proposed. A fabrication process for the stator resonator compatible with both bulk micromachining and 0.3 μm PZT films deposition on a SiNx/Ta/Pt substrate has been tested. Comparison of PZT actuated and previously fabricated ZnO actuated diaphragms are performed using laser interferometry. PZT samples show promising results for applications where a low voltage operation is a key benefit. Poled PZT films are obtained after process completion and influence of DC biases on the resonance frequencies are observed.     

Long-term enhancement of entorhinal-dentate evoked potentials following 'modified' ECS in the rat

Electroconvulsive therapy (ECT) is widely used as a treatment for drug-resistant depression. The animal analogue of ECT is electroconvulsive shock (ECS) seizures. We have recently shown that repeated ECS seizures cause a long-lasting, perhaps permanent, enhancement in entorhinal-dentate evoked potentials in the rat. Our study, however, involved 'unmodified' ECS, whereas in clinical practice ECT is now usually given in its 'modified' form (with near-threshold currents, a short-acting barbiturate, muscle relaxant and oxygen). We have therefore repeated our experiments using modified ECS. Entorhinal-dentate evoked potentials were measured in Long-Evans rats before and after: (1) eight modified ECS seizures; or (2) eight sham modified ECS trials. Despite the use of the modified procedure, a significant and long-lasting enhancement in population spike amplitude was seen in the ECS group. We conclude that the modified procedure does not protect rats against the long-lasting enhancement of evoked potentials. Similar changes may be occurring in the brains of patients subjected to modified ECT.