1,357 research outputs found
Improving the Efficiency of a Nuclear Power Plant Using a Thermoelectric Cogeneration System
The efficiencies of nuclear power plants are rather poor having the ratio %30 by using the conventional energy/exergy tools. According to that information, large amount of energy is wasted during condensation and thrown out to the environment. Thermoelectric generator (TEG) system has a potential to be used as a heat exchanging technology to produce power with a relatively low efficiency (about 5%) and it can transform the temperature difference into electricity and generate clean electrical energy. In the present study, we offer a novel system to recover the waste heat from a VVER-1000 nuclear power plant. The heat transfer of the TEG is analyzed numerically with respect to the various temperature ranges and constant mass flow rate of the exhaust steam entering the system. In the analyses, different hot temperature ranges (35ºC, 45ºC and 55ºC) and a constant cold temperature (i.e. 18ºC) are used for a HZ-20 thermoelectric module and it has been proven that the designed TEG can produce the maximum output power of 76,956 MW for a temperature difference ∆T=37 and the conversion efficiency of 3.854% sits. The TEG is designed for the condenser of a 1000 MW nuclear power plant. It\u27s shown that about 2.0% increasing in the power plant efficiency is expected by using the selected thermoelectric generator in the condensation cycle.Article History: Received: July 15th 2017; Received: October 17th 2017; Accepted: February 13rd 2018; Available onlineHow to Cite This Article: Terzi, R. and Kurt, E. (2018), Improving the efficiency of a nuclear power plant using a thermoelectric cogeneration system, Int. Journal of Renewable Energy Development, 7(1), 77-84.https://doi.org/10.14710/ijred.7.1.77-8
Juglone effects on seedling growth in intact and coatless seeds of muskmelon
Elongation, fresh and dry weights of muskmelon seedlings (Cucumis melo cv. Ký kavunu) were enhanced by juglone in intact seeds. In the case of coatless seeds, root elongation decreased but fresh and dry weight of the seedlings were increased by juglone. While protein content was slightly increased by juglone in cotyledons of intact seeds, it did not change significantly in coatless seeds. Catechol oxidizing activity of polyphenol oxidase (PPO) enzyme increased in cotyledons of juglone treated intactseeds whereas it did not change significantly in coatless seeds
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Failure of Sterne- and Pasteur-Like Strains of Bacillus anthracis to Replicate and Survive in the Urban Bluebottle Blow Fly Calliphora vicina under Laboratory Conditions
Britta von Terzi, Peter C. B. Turnbull, Wolfgang Beyer, University of Hohenheim, Institute of Environmental and Animal Hygiene, Stuttgart, GermanySteve E. Bellan, Center for Computational Biology and Bioinformatics, University of Texas at Austin, Austin, Texas, United States of AmericaThis study aimed to elucidate the bacteriological events occurring within the gut of Calliphora vicina, selected as the European representative of blow flies held responsible for the spread of anthrax during epidemics in certain parts of the world. Green-fluorescent-protein-carrying derivatives of Bacillus anthracis were used. These lacked either one of the virulence plasmids pXO1 and pXO2 and were infected, or not infected, with a worm intestine phage (Wip4) known to influence the phenotype and survival of the pathogen. Blood meals were prepared for the flies by inoculation of sheep blood with germinated and, in case of pXO2+ strains, encapsulated cells of the four B. anthracis strains. After being fed for 4 h an initial 10 flies were externally disinfected with peracetic acid to ensure subsequent quantitation representing ingested B. anthracis only. Following neutralization, they were crushed in sterile saline. Over each of the ensuing 7 to 10 days, 10 flies were removed and processed the same way. In the absence of Wip4, strains showed steady declines to undetectable in the total B. anthracis counts, within 7–9 days. With the phage infected strains, the falls in viable counts were significantly more rapid than in their uninfected counterparts. Spores were detectable in flies for longer periods than vegetative bacteria. In line with the findings in both biting and non-biting flies of early workers our results indicate that B. anthracis does not multiply in the guts of blow flies and survival is limited to a matter of days.This work was funded by grant BE 2157/3-1 of the German Research Foundation (DFG). SEB was funded by a United States National Institute of General Medical Sciences MIDAS grant U01GM087719 to Lauren A. Meyers and Alison P. Galvani. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Center for Computational Biology and BioinformaticsEmail: [email protected]
LSTM neural networks: Input to state stability and probabilistic safety verification
The goal of this paper is to analyze Long Short Term Memory (LSTM) neural networks from a dynamical system perspective. The classical recursive equations describing the evolution of LSTM can be recast in state space form, resulting in a time-invariant nonlinear dynamical system. A sufficient condition guaranteeing the Input-to-State (ISS) stability property of this class of systems is provided. The ISS property entails the boundedness of the output reachable set of the LSTM. In light of this result, a novel approach for the safety verification of the network, based on the Scenario Approach, is devised. The proposed method is eventually tested on a pH neutralization process
Effects of weed control practices on plant diversity in a homogenous olive-dominated landscape (South-east of Italy)
Olive groves represent an important economic, agro-ecological, and cultural resource in the Mediterranean Basin. Weed management plays a fundamental role in their sustainable management. The aim of this work was to characterize and assess the plant diversity associated with different weed control practices, in a homogeneous olive-dominated landscape in the South-East of Italy. Sixty-five vegetation plots were sampled in orchards treated with different weed control practices: mowing, tillage, and use of chemical herbicides. The multi-response permutation procedure was used to test the hypothesis of no difference among the treatments. The relationships between plots were visualized by means of non-metric multidimensional scaling ordination. A generalized linear mixed model was used to analyze the relationships between weed control practices and life forms, chorotypes, and diversity indexes. The results showed that the three weed control practices determined slightly different plant communities. Chemically weeded orchards showed an impoverished floristic composition and the lowest diversity, whereas mowing and tillage yielded similar values. These latter two treatments differed for the percentages of hemicryptophytes and therophytes. Moreover, different from other studies, we did not find plant species of particular concern for biodiversity conservation. We hypothesize that this result is due to the monotonous structure of the agro-landscape we investigated, where natural elements are almost lacking. From this point of view, a correct management of agro-districts should consider both the agronomic practices at the level of the individual olive groves and the structure of the agro-landscape
Produção de lipase por duas cepas de Aspergillus niger por fermentação em estado sólido e submersa.
Comparação da produção das enzimas xilanase e feruloil esterase em fermentação em estado sólido e submersa pela cepa mutante Aspergillus niger 3T5B8.
Topical Treatment with Cord Blood Serum in Glaucoma Patients: A Preliminary Report
Purpose. To report data happened to be observed in two glaucoma patients treated with Cord Blood Serum (CBS) eyedrops.
Design. Case report. Retrospective data analysis
Methods. CBS topical eyedrops, characterized in advance for growth factors (GFs) content, were administered for two months with the aim to relieve their subjective symptoms, in two patients who had referred ocular surface discomfort, although in absence of any sign of keratopathy. As patients were also affected by advanced glaucoma at risk of vision loss, and under treatment with hypotensive drugs, they had been also monitored over the same period with IOP controls and Visual field tests in our Unit.
Results. During subsequent visits, data from Mean Deviation and Pattern Standard Deviation in the Visual fields were retrospectively collected and compared before and after treatment with CBS, and an amelioration was observed.
Conclusions. CBS contains a combination of GFs, which potentially exert a neuroprotective action and candidate CBS as an interesting natural source to be delivered in neurodegenerative ocular disorders. The incidentally observed amelioration in these two patients deserves further investigation in this respec
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