965 resultados para SRM module
Resumo:
Summary
-Predatory functional responses play integral roles in predator–prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species.
-Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator–prey interactions and thus the predictive capability of the comparative functional response approach.
-We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses.
-Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator.
-Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator.
-This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies.
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Photovoltaic (PV) solar power generation is proven to be effective and sustainable but is currently hampered by relatively high costs and low conversion efficiency. This paper addresses both issues by presenting a low-cost and efficient temperature distribution analysis for identifying PV module mismatch faults by thermography. Mismatch faults reduce the power output and cause potential damage to PV cells. This paper first defines three fault categories in terms of fault levels, which lead to different terminal characteristics of the PV modules. The investigation of three faults is also conducted analytically and experimentally, and maintenance suggestions are also provided for different fault types. The proposed methodology is developed to combine the electrical and thermal characteristics of PV cells subjected to different fault mechanisms through simulation and experimental tests. Furthermore, the fault diagnosis method can be incorporated into the maximum power point tracking schemes to shift the operating point of the PV string. The developed technology has improved over the existing ones in locating the faulty cell by a thermal camera, providing a remedial measure, and maximizing the power output under faulty conditions.
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This discussion paper outlines an approach to developing and evaluating an educative programme primarily delivered by lay `citizen trainers’ in educating student nurses, and student midwives to the impact of and experience of extended and extensive civil unrest within their communities (`the Troubles’ ). This is drawn from experience within the Northern Ireland `Troubles’ and all of the citizen trainers were directly affected physically/psychologically. The programme was intended to both educate but primarily to help facilitate student nurses and student midwives to better understanding to experience and context and to more effective care delivery to those affected by/damaged by `the Troubles’. Evaluation of the teaching and learning by the students was significantly positive.
Challenges in measuring the diagnostic and treatment interval within Northern Ireland; ICBP module 4
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Electric vehicles (EVs) and hybrid EVs are the way forward for green transportation and for establishing low-carbon economy. This paper presents a split converter-fed four-phase switched reluctance motor (SRM) drive to realize flexible integrated charging functions (dc and ac sources). The machine is featured with a central-tapped winding node, eight stator slots, and six rotor poles (8/6). In the driving mode, the developed topology has the same characteristics as the traditional asymmetric bridge topology but better fault tolerance. The proposed system supports battery energy balance and on-board dc and ac charging. When connecting with an ac power grid, the proposed topology has a merit of the multilevel converter; the charging current control can be achieved by the improved hysteresis control. The energy flow between the two batteries is balanced by the hysteresis control based on their state-of-charge conditions. Simulation results in MATLAB/Simulink and experiments on a 150-W prototype SRM validate the effectiveness of the proposed technologies, which may provide a solution to EV charging issues associated with significant infrastructure requirements.
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Electric vehicles (EVs) and hybrid electric vehicles (HEVs) can reduce greenhouse gas emissions while switched reluctance motor (SRM) is one of the promising motor for such applications. This paper presents a novel SRM fault-diagnosis and fault-tolerance operation solution. Based on the traditional asymmetric half-bridge topology for the SRM driving, the central tapped winding of the SRM in modular half-bridge configuration are introduced to provide fault-diagnosis and fault-tolerance functions, which are set idle in normal conditions. The fault diagnosis can be achieved by detecting the characteristic of the excitation and demagnetization currents. An SRM fault-tolerance operation strategy is also realized by the proposed topology, which compensates for the missing phase torque under the open-circuit fault, and reduces the unbalanced phase current under the short-circuit fault due to the uncontrolled faulty phase. Furthermore, the current sensor placement strategy is also discussed to give two placement methods for low cost or modular structure. Simulation results in MATLAB/Simulink and experiments on a 750-W SRM validate the effectiveness of the proposed strategy, which may have significant implications and improve the reliability of EVs/HEVs.
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Enterobacter species commonly occur in the environment and are recognized as opportunistic human pathogens in clinical settings. However, with the exception of Enterobacter sakazakii (Cronobacter), Enterobacter species are not normally considered foodborne pathogens. Cronobacter are particularly associated with illness in infants, particularly within the first 3 months after birth. Therefore, although Cronobacter are found in a wide range of fresh and dried food materials, it is their contamination of the infant formula production chain that is the major cause for concern. Cronobacter are noted for their ability to survive during desiccation and their persistence in dried infant food for at least 2 years.
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Aims : This study evaluates the impact of a Developmental Coordination Disorder (DCD) evidence-based online module including synthesized resources, practical strategies, and interactive component on self-reported physical therapist (PT) knowledge, skills, and practice. Methods : PTs from across Canada completed questionnaires before, immediately after, and 2 months following completion of the module. Questionnaires used 7-point Likert scale items and short open-ended questions; analyzes used paired t-tests and a thematic approach. Results : Fifty PTs completed both pre- and post-questionnaires; 41 of these completed the follow-up questionnaire. Most items (79%) evaluating self-reported knowledge and skills increased significantly following module completion and this increase was maintained two months later. Most participants (92%) reported an increase in their confidence to provide DCD evidence-based services. Participants plan to modify their evaluative practices (e.g., involving children in goal setting) and their management of DCD (e.g., using best practice principles, providing resources to families and physicians). At the 2- month follow-up, 46% of participants had returned to the module to review information (e.g., video, resources) or to download handouts. Conclusion : An online module developed collaboratively with PTs has the potential not only to increase PTs’ knowledge, but also to support them in implementing evidence-based services for children with DCD.
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Aims: Developmental Coordination Disorder (DCD) is a chronic condition with potential negative health consequences. Clinicians working with children with DCD need access to tailored, synthesized, evidence-based DCD information; however a knowledge-to-practice gap exists. The aim of this study was to develop and evaluate an evidence-based online DCD module tailored to physical therapists’ (PTs) identified needs. Methods: Guided by the Knowledge to Action framework, we interviewed PTs working with children with DCD (n=9) to identify their information needs. Their recommendations, along with synthesized DCD research evidence, informed module development. PTs (n=50) responded to scaled items and open-ended questions to evaluate module usefulness. Results: The module incorporated important PT DCD content areas including: 1) Identification; 2) Planning Interventions and Goals; 3) Evidence-Based Practice; 4) Management; and, 5) Resources. Case scenarios, clinical applications, interactive media, links to resources, and interactive learning opportunities were also embedded. PTs perceived the module to be comprehensive and useful and provided feedback to improve module navigation. Conclusions: Involving end-users throughout the development and evaluation of an online PT DCD module contributed to its relevance, applicability, and utility. The ongoing clinical use of this module may have the potential to improve the quality of PT DCD services.
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LGVs are of ever-greater importance in terms of the final delivery of many time-critical, high value goods and are also widely used in industries that provide a wide range of critical support services. There are almost five times as many LGVs as there are HGVs (goods vehicles over 3.5 tonnes gross vehicle weight) currently licensed in Britain. The LGV fleet in Britain is growing at a faster rate than the HGV fleet, and the LGV fleet travels more than twice as many vehicle kilometres each year than the total HGV fleet. LGVs perform a far greater proportion of their total distance travelled in urban areas than HGVs, and consume 25% of the total diesel and 3% of the total petrol used by all motorised road transport vehicles in Britain.
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The review illustrates the importance of road movements in goods distribution in urban areas. It highlights the major economic, environmental and social impacts associated with this freight activity and reviews policy options available to those responsible for regulation. A wide range of possible solutions to problems posed by urban freight operations are also covered including approaches related to: consolidation, facilities, vehicle design, information capture and utilisation, and non-road modes.