22,907 research outputs found

    Application of a simplified thermal-electric model of a sodium-nickel chloride battery energy storage system to a real case residential prosumer

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    Recently, power system customers have changed the way they interact with public networks, playing a more and more active role. End-users first installed local small-size generating units, and now they are being equipped with storage devices to increase the self-consumption rate. By suitably managing local resources, the provision of ancillary services and aggregations among several end-users are expected evolutions in the near future. In the upcoming market of household-sized storage devices, sodium-nickel chloride technology seems to be an interesting alternative to lead-acid and lithium-ion batteries. To accurately investigate the operation of the NaNiCl2 battery system at the residential level, a suitable thermoelectric model has been developed by the authors, starting from the results of laboratory tests. The behavior of the battery internal temperature has been characterized. Then, the designed model has been used to evaluate the economic profitability in installing a storage system in the case that end-users are already equipped with a photovoltaic unit. To obtain realistic results, real field measurements of customer consumption and solar radiation have been considered. A concrete interest in adopting the sodium-nickel chloride technology at the residential level is confirmed, taking into account the achievable benefits in terms of economic income, back-up supply, and increased indifference to the evolution of the electricity market

    Isothermal heat flux sensing unit Final report, Jun. 21, 1967 - Jan. 2, 1968

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    Thermal analysis, theory of operation, and operating instructions for isothermal heat flux sensing uni

    Sustainable seabed mining: guidelines and a new concept for Atlantis II Deep

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    The feasibility of exploiting seabed resources is subject to the engineering solutions, and economic prospects. Due to rising metal prices, predicted mineral scarcities and unequal allocations of resources in the world, vast research programmes on the exploration and exploitation of seabed minerals are presented in 1970s. Very few studies have been published after the 1980s, when predictions were not fulfilled. The attention grew back in the last decade with marine mineral mining being in research and commercial focus again and the first seabed mining license for massive sulphides being granted in Papua New Guinea’s Exclusive Economic Zone.Research on seabed exploitation and seabed mining is a complex transdisciplinary field that demands for further attention and development. Since the field links engineering, economics, environmental, legal and supply chain research, it demands for research from a systems point of view. This implies the application of a holistic sustainability framework of to analyse the feasibility of engineering systems. The research at hand aims to close this gap by developing such a framework and providing a review of seabed resources. Based on this review it identifies a significant potential for massive sulphides in inactive hydrothermal vents and sediments to solve global resource scarcities. The research aims to provide background on seabed exploitation and to apply a holistic systems engineering approach to develop general guidelines for sustainable seabed mining of polymetallic sulphides and a new concept and solutions for the Atlantis II Deep deposit in the Red Sea.The research methodology will start with acquiring a broader academic and industrial view on sustainable seabed mining through an online survey and expert interviews on seabed mining. In addition, the Nautilus Minerals case is reviewed for lessons learned and identification of challenges. Thereafter, a new concept for Atlantis II Deep is developed that based on a site specific assessment.The research undertaken in this study provides a new perspective regarding sustainable seabed mining. The main contributions of this research are the development of extensive guidelines for key issues in sustainable seabed mining as well as a new concept for seabed mining involving engineering systems, environmental risk mitigation, economic feasibility, logistics and legal aspects

    Evaluating techniques in tissue clarification using CLARITY imaging and investigating where sodium is sensed in the body

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    OBJECTIVE: Previous studies have shown the significant contribution of sympathoinhibition in response to sodium loading to prevent increases in mean arterial blood pressure in salt resistant phenotypes. It has also been shown that brain Gαi2 protein gated signal transduction plays a major role in this pathway, however, the specific mechanisms through which this pathway is activated remain less well understood. The purpose of this study was to elucidate the relative contribution of increased sodium in either the plasma or the cerebrospinal fluid (CSF) to the regulation of mean arterial pressure and natriuresis. Additionally we explored the potential for using the novel CLARITY Imaging technique to identify the relative activity of neurons in areas of the brain thought to play a major role in body fluid homeostasis in response to salt. METHODS: Rats that were pre-treated with either scrambled or Gαi2 oligodeoxynucleotides (ODN), to selectively down regulate brain Gαi2 proteins, were challenged either peripherally or centrally with sodium. Upon sodium loading physiological parameters were measured for two hours after which the animal's brains were recovered for immunohistochemical (IHC) analysis of the paraventricular nucleus, a known regulatory center for body fluid homeostasis and blood pressure regulation. Additionally we adapted a version of the published CLARITY Imaging protocols for optically clearing tissue through application of electrophoretic tissue clearing (ETC) to a larger rat model. RESULTS: In scrambled ODN pre-treated rats we observed a temporary increase in MAP in response to both the peripheral and central sodium challenge. In the Gαi2 ODN pre-treated animals we saw some form of attenuation to this response in both studies, however, where in the peripheral challenge there was an increase in the amount of time that it took the rats to return to normotension with no alteration in natriuresis, in the central challenge there was a large attenuation in natriuresis with no differences in the time to return to baseline MAP. Our IHC analysis also showed a decrease in neuronal activation of paraventricular medial parvocellular neurons in Gαi2 pre-treated rats that were challenged peripherally vs their SCR pre-treated counterparts. No such difference was observed in either of the pre-treatment groups from the central sodium challenge study. In the CLARITY study we found that it is possible to adapt the method for optically clearing tissue to the larger model, however, we encountered several issues related to tissue swelling and peripheral tissue damage. CONCLUSION: Based on our current results it seems evident that there are at least two different mechanisms that activate the cardiovascular regulatory control centers in the brain that prevent long term increases in mean arterial pressure in response to increased salt. It also appears that these two different mechanisms are triggered either by increases in plasma or CSF salinity, though which of these two mechanisms may be directly responsible for the development of salt sensitive hypertension requires further investigation. While we had some success at optically clearing larger tissue volumes through ETC, problems we encountered with maintaining tissue integrity for investigations of intact neural networks prevented us from applying this technique, in its current form, to our investigation of salt sensitive hypertension

    Evaluating the direct costs of controlling NOx emissions in Europe

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    This study summarises the available information on the costs of those nitrogen oxides abatement technologies in operation at present or coming into operation in the near future. Relying on disaggregated source data and using engineering cost functions and various technical and economic assumptions, the least cost curves of nitrogen oxides abatement for all the European countries have been derived and some examples are presented.Denitrification; Abatement costs
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