566 research outputs found
The Knock-Limited Performance of Fuel Blends Containing Aromatics V : N-Propylbenzene, N-Butylbenzene, Isobutylbenzene, M-Xylene, and 1-Isopropyl-4-Methylbenzene
Results are reported of knock-limited tests of five aromatics, each individually blended with selected base fuels and tested with and without TEL, using 17.6, F-4, and F-3 small-scale engines. The five aromatics rated in the following order of decreasing antiknock effectiveness at fuel/air ratio 0.10: m-xylene, 1-isopropyl-4-methylbenzene, n-propylbenzene, isobutylbenzene, and n-butylbenzene
A sunny future: expert elicitation of China's solar photovoltaic technologies
China has emerged as the global manufacturing center for solar photovoltaic (PV) products. Chinese firms have entered all stages of the supply chain, producing most of the installed solar modules around the world. Meanwhile, production costs are at record lows. The decisions that Chinese solar producers make today will influence the path for the solar industry and its role towards de-carbonization of global energy systems in the years to come. However, to date, there have been no assessments of the future costs and efficiency of solar PV systems produced by the Chinese PV industry. We perform an expert elicitation to assess the technological and non-technological factors that led to the success of China's silicon PV industry as well as likely future costs and performance. Experts evaluated key metrics such as efficiency, costs, and commercial viability of 17 silicon and non-silicon solar PV technologies by 2030. Silicon-based technologies will continue to be the mainstream product for large-scale electricity generation application in the near future, with module efficiency reaching as high as 23% and production cost as low as 34/MWh, allowing solar PV to be competitive with traditional energy resources like coal. The industry's future developments may be affected by overinvestment, overcapacity, and singular short-term focus.info:eu-repo/semantics/publishedVersio
China's wind industry: leading in deployment, lagging in innovation
China's massive carbon emissions and air pollution concerns have led its government to embrace clean energy innovation as a means of transitioning to a more sustainable energy system. We address the question of whether China's wind industry has become an important source of clean energy technology innovation. We find that in terms of wind capacity expansion, China has delivered enormous progress, increasing its wind capacity from virtually no wind capacity in the early 2000s to 140 GW by 2015. However, in terms of innovation and cost competitiveness, the outcomes were more limited: Chinese wind turbine manufacturers have secured few international patents and achieved moderate learning rates compared to the global industry's historical learning rate. Leading China-based indigenous producers are likely to remain important global players for the foreseeable future, but further progress in reducing the cost of capital equipment may slow relative to the recent past. However, opportunities in lowering curtailment rates and improving turbine quality can reduce China's overall levelized cost of electricity for wind.info:eu-repo/semantics/publishedVersio
China's wind electricity and cost of carbon mitigation are more expensive than anticipated
The success of China's transition to a low-carbon energy system will be key to achieve the global level of emissions reductions needed to avoid large negative consequences from climate change. China is undergoing an impressive build up of renewable capacity, in particular wind. Using data from the Clean Mechanism Development project database between 2004 and 2012, this study shows that while China made progress in bringing down the levelized cost of wind electricity and cost of carbon mitigation (CCM), serious grid-connection issues and high wind curtailment rates resulted in a levelized cost of wind electricity that is one-half to two times higher than expected, and a CCM that is four to six times higher. Sharp drop in electricity demand, utilization rate, and coal prices in recent years may lead to even higher results.info:eu-repo/semantics/publishedVersio
Practice Matters: Screening and Caring for Those with Hypertension
The purpose of this article is to review best practices for screening and monitoring hypertension for Faith Community Nurses (FCNs). Epidemiological data regarding hypertension will be presented, along with current guidelines for blood pressure monitoring. Information on lifestyle modification and patient education resources is included to assist the FCN to improve service to patients at risk for and with current hypertension
An investigation of the existence of a surface water layer on aircraft radomes during simulated flight in heavy precipitation
An experiment to investigate the electromagnetic attenuation effects of an impacting water spray on an aircraft weather radome was conducted in Langley's 4 X 7 m. wind tunnel equipped with a water spray system. Results indicate no significant liquid water film formed at the stagnation point of the radome under the test conditions. However, a water sheath was observed standing away from the radome surface, which could possibly have significant attenuation properties of its own. Due to the lack of fidelity in modeling both the natural environment with the tunnel apparatus and the water sheath, it is recommended that further studies be undertaken to better define the water distribution in the vicinity of the radome and measure its effect on weather radar performance
Organization of Multinational Activities and Ownership Structure
We develop a model in which multinational investors decide about the modes of organization, the locations of production, and the markets to be served. Foreign investments are driven by market-seeking and cost-reducing motives. We further assume that investors face costs of control that vary among sectors and increase in distance. The results show that (i) production intensive sectors are more likely to operate a foreign business independent of the investment motive, (ii) that distance may have a non-monotonous effect on the likelihood of horizontal investments, and (iii) that globalization, if understood as reducing distance, leads to more integration
Spatial and seasonal differences in the top predators of Easter Island: Essential data for implementing the new Rapa Nui multiple‐uses marine protected area
Reef fishes are an important component of marine biodiversity, and changes in the composition of the assemblage structure may indicate ecological, climatic, or anthropogenic disturbances. To examine spatial differences in the reef fish assemblage structure around Easter Island, eight sites were sampled during autumn and summer 2016–2017 with baited remote underwater video systems. To determine seasonal changes, quarterly (seasonal) sampling was conducted at five of those eight sites. Fifteen pelagic species of fishes were recorded during this study, some of which have not previously been recorded in scuba surveys, including the Galapagos shark (Carcharhinus galapagensis, Snodgrass & Heller, 1905) and tunas (Scrombidae). Significant spatial and seasonal differences were found in the fish assemblage. Fish assemblages from the south coast differed significantly from those along the west and east coasts, mainly due to the occurrence of top predators. Winter differed from other seasons, especially along the south coast where the island is more exposed to large oceanic swells and winds from Antarctica. Owing to the variety and high relative abundance of species recorded during this survey, baited remote underwater video systems seemed to be an effective method for studying top predators at Easter Island. The identification of priority zones for the protection of top predator species represents an important contribution of this study, in order to develop management and conservation strategies to be implemented in the newly created Rapa Nui multiple uses coastal marine protected areas
Does improved access to diagnostic imaging results reduce hospital length of stay? A retrospective study
<p>Abstract</p> <p>Background</p> <p>One year after the introduction of Information and Communication Technology (ICT) to support diagnostic imaging at our hospital, clinicians had faster and better access to radiology reports and images; direct access to Computed Tomography (CT) reports in the Electronic Medical Record (EMR) was particularly popular. The objective of this study was to determine whether improvements in radiology reporting and clinical access to diagnostic imaging information one year after the ICT introduction were associated with a reduction in the length of patients' hospital stays (LOS).</p> <p>Methods</p> <p>Data describing hospital stays and diagnostic imaging were collected retrospectively from the EMR during periods of equal duration before and one year after the introduction of ICT. The post-ICT period was chosen because of the documented improvement in clinical access to radiology results during that period. The data set was randomly split into an exploratory part used to establish the hypotheses, and a confirmatory part. The data was used to compare the pre-ICT and post-ICT status, but also to compare differences between groups.</p> <p>Results</p> <p>There was no general reduction in LOS one year after ICT introduction. However, there was a 25% reduction for one group - patients with CT scans. This group was heterogeneous, covering 445 different primary discharge diagnoses. Analyses of subgroups were performed to reduce the impact of this divergence.</p> <p>Conclusion</p> <p>Our results did not indicate that improved access to radiology results reduced the patients' LOS. There was, however, a significant reduction in LOS for patients undergoing CT scans. Given the clinicians' interest in CT reports and the results of the subgroup analyses, it is likely that improved access to CT reports contributed to this reduction.</p
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