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System Operating (system + operating)
Selected AbstractsA review on energy, economical, and environmental benefits of the use of CHP systems for small commercial buildings for the North American climateINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 14 2009P. J. Mago Abstract The use of combined heating and power (CHP) systems to produce both electricity and heat is increasing rapidly due to their high potential of reducing primary energy consumption (PEC), cost, and emissions in domestic, commercial, and industrial applications. In addition to producing both electricity and heat, CHP systems can be coupled with vapor compression systems to provide cooling. This paper analyzes a natural gas engine CHP system together with a vapor compression system for different American climate zones. Performance is measured in terms of operational costs, PEC, and carbon dioxide emissions as a percent of a reference building. The objective of this paper is to compare the performance of a CHP system operating 24,h a day with a system that only operates during typical office hours. Furthermore, the system is optimized based on reducing PEC, minimizing costs, and reducing emissions. In addition, the benefits of CHP systems based on the Energy Star program and the Leadership in Energy and Environmental Design (LEED) program are presented. Results show that, in general, it is more beneficial to operate the CHP system during typical office hours than to operate the system 24,h a day. Also, the CHP system performance strongly depends on the location where it is installed. In addition to reductions in cost, primary energy, and emissions, CHP systems can help achieve the Energy Star label for commercial office buildings and help obtain LEED points that go toward achieving LEED certification status. Copyright © 2009 John Wiley & Sons, Ltd. [source] Performance characteristics and modelling of a micro gas turbine for their integration with thermally activated cooling technologiesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 2 2007Adrián Vidal Abstract We have developed a simple model of a micro gas turbine system operating at high ambient temperatures and characterized its performance with a view to integrating this system with thermally activated cooling technologies. To develop and validate this model, we used experimental data from the micro gas turbine test facility of the CREVER research centre. The microturbine components were modelled and the thermodynamic properties of air and combustion gases were estimated using a commercial process simulator. Important information such as net output power, microturbine fuel consumption and exhaust gas mass flow rate can be obtained with the empirical correlations we have developed in this study. This information can be useful for design exhaust gas fired absorption chillers. Copyright © 2006 John Wiley & Sons, Ltd. [source] Performance of a turbo-coded CDMA system in a mobile satellite channelINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 4 2005Jin Young Kim Abstract The bit error rate (BER) performance of a turbo-coded code-division multiple-access (CDMA) system operating in a satellite channel is analysed and simulated. The system performance is compared for various constituent decoders, including maximum a posteriori probability (MAP) and Max-Log-MAP algorithms, and the soft-output Viterbi algorithm. The simulation results indicate that the Max-Log-MAP algorithm is the most promising among these three algorithms in overall terms of performance and complexity. It is also shown that, for fixed code rate, the BER performance is improved substantially by increasing the number of iterations in the turbo decoder, or by increasing the interleaver length in the turbo encoder. The results in this paper are of interest in CDMA-based satellite communications applications. Copyright © 2005 John Wiley & Sons, Ltd. [source] Analyzing the real advantages of bifunctional initiator over monofunctional initiator in free radical polymerizationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Paula F. de M. P. B. Machado Abstract Monofunctional initiators are extensively used in free radical polymerization. To enhance productivity, a higher temperature is usually used; however, this leads to lower molecular weights. Bifunctional initiators can increase the polymerization rate without decreasing the average molecular weight and this can be desirable. A bifunctional initiator is an important issue to be investigated, and it is of great interest to industries. The objective of this work is to study polymerization reactions with mono- and bi-functional initiators through comprehensive mathematical models. Polystyrene is considered as case study. This work collects and presents some experimental data available in literature for polymerization using two different types of bifunctional initiators. Model prediction showed good agreement with experimental data. It was observed that the initial initiator concentration has a huge impact on the efficiency of initiators with functionality bigger than one and high concentrations of bifunctional initiator make the system behave as if it were a system operating with monofunctional initiator. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Carbohydrate,protein interactions between HNK-1-reactive sulfoglucuronyl glycolipids and the proteoglycan lectin domain mediate neuronal cell adhesion and neurite outgrowthJOURNAL OF NEUROCHEMISTRY, Issue 2 2001Ryu Miura Lecticans, a family of chondroitin sulfate proteoglycans, represent the largest group of proteoglycans expressed in the nervous system. We previously showed that the C-type lectin domains of lecticans bind two classes of sulfated cell surface glycolipids, sulfatides and HNK-1-reactive sulfoglucuronylglycolipids (SGGLs). In this paper, we demonstrate that the interaction between the lectin domain of brevican, a nervous system-specific lectican, and cell surface SGGLs acts as a novel cell recognition system that promotes neuronal adhesion and neurite outgrowth. The Ig chimera of the brevican lectin domain bind to the surface of SGGL-expressing rat hippocampal neurons. The substrate of the brevican chimera promotes adhesion and neurite outgrowth of hippocampal neurons. The authentic, full-length brevican also promotes neuronal cell adhesion and neurite outgrowth. These activities of brevican substrates are neutralized by preincubation of cells with HNK-1 monoclonal antibodies and by pretreatment of the brevican substrates with purified SGGLs. Brevican and HNK-1 carbohydrates are coexpressed in specific layers of the developing hippocampus where axons from entorhinal neurons elongate. Our observations suggest that cell surface SGGLs and extracellular lecticans comprise a novel cell-substrate recognition system operating in the developing nervous system. [source] Evaluation of corrosion inhibitors for cooling water systems operating at high concentration cyclesMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 5 2009E. A. de Souza Abstract The present work aimed at evaluating AISI 1020 carbon steel corrosion resistance of a 6:4:1:1 (MoO/HEDP/PO/Zn2+) inhibitor mixture present in a solution which simulates an industrial cooling water system operating at high concentration cycles (1050 ppm Cl, and 450 ppm Ca2+). High concentration cycles are desirable, because system purge and treated water consumption are decreased. On the other hand, a high number of concentration cycles can increase the concentration of salts and dissolved impurities, causing corrosion, incrustations, and deposits inside the pipes, heat exchangers, and cooling towers. Thus, the chloride (Cl,) and calcium (Ca2+) ions aggressiveness was studied on the proposed inhibiting mixture, at the temperatures of 40 and 60,°C, through electrochemical techniques like open circuit potential measurements, anodic and cathodic polarization, and weight loss. The results showed that the inhibitor mixture conferred adequate protection to carbon steel in low concentrations, even in high aggressive media. [source] SCM transmission in MM fiber with automatic selection of the subcarrier frequencyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2009Marcin Kowalczyk Abstract Demonstrated was a 10 Mbit/s binary frequency shift keying subcarrier multiplexing system operating beyond the pass-band of 1 km MM graded index optical fiber. The system automatically adjusted the carrier frequency to the fiber frequency response. Transmission of four 10 Mbit/s channels was also shown over the same fiber. No visible channel interaction was observed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1212,1214, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24277 [source] Low-power millimeter wave radiations do not alter stress-sensitive gene expression of chaperone proteinsBIOELECTROMAGNETICS, Issue 3 2007M. Zhadobov Abstract This article reports experimental results on the influence of low-power millimeter wave (MMW) radiation at 60 GHz on a set of stress-sensitive gene expression of molecular chaperones, namely clusterin (CLU) and HSP70, in a human brain cell line. Selection of the exposure frequency is determined by its near-future applications for the new broadband civil wireless communication systems including wireless local area networks (WLAN) for domestic and professional uses. Frequencies around 60 GHz are strongly attenuated in the earth's atmosphere and such radiations represent a new environmental factor. An exposure system operating in V-band (50,75 GHz) was developed for cell exposure. U-251 MG glial cell line was sham-exposed or exposed to MMW radiation for different durations (1,33 h) and two different power densities (5.4 µW/cm2 or 0.54 mW/cm2). As gene expression is a multiple-step process, we analyzed chaperone proteins induction at different levels. First, using luciferase reporter gene, we investigated potential effect of MMWs on the activation of transcription factors (TFs) and gene promoter activity. Next, using RT-PCR and Western blot assays, we verified whether MMW exposure could alter RNA accumulation, translation, or protein stability. Experimental data demonstrated the absence of significant modifications in gene transcription, mRNA, and protein amount for the considered stress-sensitive genes for the exposure durations and power densities investigated. The main results of this study suggest that low-power 60 GHz radiation does not modify stress-sensitive gene expression of chaperone proteins. Bioelectromagnetics 28:188,196, 2007. © 2006 Wiley-Liss, Inc. [source] | ||||||||||||||||