38 research outputs found

    Analysis of the Patent of a Protective Cover for Vertical-Axis Wind Turbines (VAWTs): Simulations of Wind Flow

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    This paper presents a numerical and experimental analysis of the patent of a device to be used in vertical-axis wind turbines (VAWTs) under extreme wind conditions. The device consists of two hemispheres interconnected by a set of conveniently implemented variable section ducts through which the wind circulates to the blades. Furthermore, the design of the cross-section of the ducts allows the control of the wind speed inside the device. These ducts are intended to work as diffusers or nozzles, depending on the needs of the installation site. Simulations were performed for the case of high-speed external wind, for which the ducts act as diffusers to reduce wind speed and maintain a well-functioning internal turbine. Four different patent designs were analyzed, focusing on turbine performance and generated power. The results indicate that the patent allows the generation of electric power for a greater range of wind speeds than with a normal wind turbine. The results support that this patent may be a good alternative for wind power generation in geographic areas with extreme weather conditions or with maintained or strong gusty wind. Experimental tests were carried out on the movement of the blades using the available model. Finally, the power curve of the model of this wind turbine was obtained.Comment: 22 pages, 15 figure

    Objective assessment of the effect of pupil size upon the power distribution of multifocal contact lenses.

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    AIM: To analytically assess the effect of pupil size upon the refractive power distributions of different designs of multifocal contact lenses. METHODS: Two multifocal contact lenses of center-near design and one multifocal contact lens of center-distance design were used in this study. Their power profiles were measured using the NIMO TR1504 device (LAMBDA-X, Belgium). Based on their power profiles, the power distribution was assessed as a function of pupil size. For the high addition lenses, the resulting refractive power as a function of viewing distance (far, intermediate, and near) and pupil size was also analyzed. RESULTS: The power distribution of the lenses was affected by pupil size differently. One of the lenses showed a significant spread in refractive power distribution, from about -3 D to 0 D. Generally, the power distribution of the lenses expanded as the pupil diameter became greater. The surface of the lens dedicated for each distance varied substantially with the design of the lens. CONCLUSION: In an experimental basis, our results show how the lenses power distribution is affected by the pupil size and underlined the necessity of careful evaluation of the patient's visual needs and the optical properties of a multifocal contact lens for achieving the optimal visual outcome

    Active site isolation in bismuth-poisoned Pd/SiO₂ catalysts for selective hydrogenation of furfural

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    Active site isolation in furfural (FA) hydrogenation was studied by poisoning a Pd catalyst with bismuth. A solution of FA in water was hydrogenated over a 5 wt% Pd/SiO₂ catalyst in a batch reactor at various reaction temperatures and pressures. Furfuryl alcohol (FAL) was an intermediate product which was further hydrogenated into tetrahydrofurfuryl alcohol (TFAL) or cyclopentanone (CPA) and cyclopentanol (CPOL). While application of hydrogen pressure above 30 bar had little effect on the hydrogenation kinetics, a reaction temperature affected product distribution and the main product changed from TFAL (at 50 °C) to FAL (100 and 150 °C). Poisoning the catalyst with Bi decreased the number of available active sites but had little effect on the turn-over frequencies, most likely because of the absence of electronic effects of Bi on Pd nanoparticles. The main reaction product over the Bi-poisoned catalyst was FAL with no FA oligomerisation products. At a reaction temperature of 150 °C, CPA was formed with a 57% yield. Considering that Bi preferentially poisons step sites of Pd, the comparison of the product distribution between the Pd and Pd-Bi catalyst as well as the literature data for the alloy Pd-Cu catalysts indicates that the active site isolation observed in the Pd-Bi catalysts is responsible for the increasing FAL and CPA selectivities and elimination of oligomer by-products

    Human-carnivore relations: conflicts, tolerance and coexistence in the American West

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    Carnivore and humans live in proximity due to carnivore recovery efforts and ongoing human encroachment into carnivore habitats globally. The American West is a region that uniquely exemplifies these human-carnivore dynamics, however, it is unclear how the research community here integrates social and ecological factors to examine human-carnivore relations. Therefore, strategies promoting human-carnivore coexistence are urgently needed. We conducted a systematic review on human-carnivore relations in the American West covering studies between 2000 and 2018. We first characterized human-carnivore relations across states of the American West. Second, we analyzed similarities and dissimilarities across states in terms of coexistence, tolerance, number of ecosystem services and conflicts mentioned in literature. Third, we used Bayesian modeling to quantify the effect of social and ecological factors influencing the scientific interest on coexistence, tolerance, ecosystem services and conflicts. Results revealed some underlying biases in human-carnivore relations research. Colorado and Montana were the states where the highest proportion of studies were conducted with bears and wolves the most studied species. Non-lethal management was the most common strategy to mitigate conflicts. Overall, conflicts with carnivores were much more frequently mentioned than benefits. We found similarities among Arizona, California, Utah, and New Mexico according to how coexistence, tolerance, services and conflicts are addressed in literature. We identified percentage of federal/private land, carnivore family, social actors, and management actions, as factors explaining how coexistence, tolerance, conflicts and services are addressed in literature. We provide a roadmap to foster tolerance towards carnivores and successful coexistence strategies in the American West based on four main domains, (1) the dual role of carnivores as providers of both beneficial and detrimental contributions to people, (2) social-ecological factors underpinning the provision of beneficial and detrimental contributions, (3) the inclusion of diverse actors, and (4) cross-state collaborative management

    Quantitative RT-PCR analysis of differentially expressed genes in Quercus suber in response to Phytophthora cinnamomi infection

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    cDNA-AFLP methodology was used to gain insight into gene fragments differentially present in the mRNA profiles of Quercus suber roots infected with zoospores of Phytophthora cinnamomi at different post challenge time points. Fifty-three transcript-derived fragments (TDFs) were identified and sequenced. Six candidate genes were selected based on their expression patterns and homology to genes known to play a role in defence. They encode a cinnamyl alcohol dehydrogenase2 (QsCAD2), a protein disulphide isomerase (QsPDI), a CC-NBS-LRR resistance protein (QsRPc), a thaumatin-like protein (QsTLP), a chitinase (QsCHI) and a 1,3-β-glucanase (QsGlu). Evaluation of the expression of these genes by quantitative polymerase chain reaction (qPCR) revealed that transcript levels of QsRPc, QsCHI, QsCAD2 and QsPDI increased during the first 24 h post-inoculation, while those of thaumatin-like protein decreased. No differential expression was observed for 1,3-β-glucanase (QsGlu).Four candidate reference genes, polymerase II (QsRPII), eukaryotic translation initiation factor 5A (QsEIF-5A), β-tubulin (QsTUB) and a medium subunit family protein of clathrin adaptor complexes (QsCACs) were assessed to determine the most stable internal references for qRT-PCR normalization in the Phytophthora-Q. suber pathosystem in root tissues. Those found to be more stable, QsRPII and QsCACs, were used as internal reference in the present work.Knowledge on the Quercus defence mechanisms against biotic stress is scarce. This study provides an insight into the gene profiling of a few important genes of Q. suber in response to P. cinnamomi infection contributing to the knowledge of the molecular interactions involving Quercus and root pathogens that can be useful in the future to understand the mechanisms underlying oak resistance to soil-borne oomycetes.Peer Reviewe

    Marine mammals and Good Environmental Status: Science, Policy and Society; Challenges and Opportunities

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    The Marine Strategy Framework Directive has become the key instrument for marine conservation in European seas. We review its implementation, focusing on cetacean biodiversity, using the examples of Spain and the Regional Seas Convention, OSPAR. The MSFD has been widely criticised for legal vagueness, lack of coordination, uncertainty about funding, and poor governance; its future role within EU Integrated Maritime Policy remains unclear. Nevertheless, the first stages of the process have run broadly to schedule: current status, environmental objectives and indicators have been described and the design of monitoring programmes is in progress, drawing on experience with other environmental legislation. The MSFD is now entering its critical phase, with lack of funding for monitoring, limited scope for management interventions, and uncertainty about how conservation objectives will be reconciled with the needs of other marine and maritime sectors, being among the main concerns. Clarity in governance, about the roles of the EU, Member States, Regional Seas Conventions and stakeholders, is needed to ensure success. However, even if (as seems likely) good environmental status cannot be achieved by 2020, significant steps will have been taken to place environmental sustainability centre-stage in the development of Integrated Maritime Policy for EU seas.Postprin

    Natural History of MYH7-Related Dilated Cardiomyopathy

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    BACKGROUND: Variants in myosin heavy chain 7 (MYH7) are responsible for disease in 1% to 5% of patients with dilated cardiomyopathy (DCM); however, the clinical characteristics and natural history of MYH7-related DCM are poorly described. OBJECTIVE: We sought to determine the phenotype and prognosis of MYH7-related DCM. We also evaluated the influence of variant location on phenotypic expression. METHODS: We studied clinical data from 147 individuals with DCM-causing MYH7 variants (47.6% female; 35.6 ± 19.2 years) recruited from 29 international centers. RESULTS: At initial evaluation, 106 (72.1%) patients had DCM (left ventricular ejection fraction: 34.5% ± 11.7%). Median follow-up was 4.5 years (IQR: 1.7-8.0 years), and 23.7% of carriers who were initially phenotype-negative developed DCM. Phenotypic expression by 40 and 60 years was 46% and 88%, respectively, with 18 patients (16%) first diagnosed at <18 years of age. Thirty-six percent of patients with DCM met imaging criteria for LV noncompaction. During follow-up, 28% showed left ventricular reverse remodeling. Incidence of adverse cardiac events among patients with DCM at 5 years was 11.6%, with 5 (4.6%) deaths caused by end-stage heart failure (ESHF) and 5 patients (4.6%) requiring heart transplantation. The major ventricular arrhythmia rate was low (1.0% and 2.1% at 5 years in patients with DCM and in those with LVEF of ≤35%, respectively). ESHF and major ventricular arrhythmia were significantly lower compared with LMNA-related DCM and similar to DCM caused by TTN truncating variants. CONCLUSIONS: MYH7-related DCM is characterized by early age of onset, high phenotypic expression, low left ventricular reverse remodeling, and frequent progression to ESHF. Heart failure complications predominate over ventricular arrhythmias, which are rare
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