Design and Validation of a Synchronous Reluctance Motor With Single Tooth Windings

This paper presents for the first time the analysis and experimental validation of a six-slot four-pole synchronous reluctance motor with nonoverlapping fractional slot-concentrated windings. The machine exhibits high torque density and efficiency due to its high fill factor coils with very short end windings, facilitated by a segmented stator and bobbin winding of the coils. These advantages are coupled with its inherent robustness and low cost. The topology is presented as a logical step forward in advancing synchronous reluctance machines that have been universally wound with a sinusoidally distributed winding. The paper presents the motor design, performance evaluation through finite element studies and validation of the electromagnetic model, and thermal specification through empirical testing. It is shown that high performance synchronous reluctance motors can be constructed with single tooth wound coils, but considerations must be given regarding torque quality and the d-q axis inductances

Drowning risk and climate change: a state-of-the-art review

Drowning and climate change are both significant global health threats, yet little research links climate change to drowning risk. Research into the epidemiology, risk factors and preventive strategies for unintentional drowning in high-income and in low-income and middle-income countries has expanded understanding, but understanding of disaster and extreme weather-related drowning needs research focus. As nation states and researchers call for action on climate change, its impact on drowning has been largely ignored. This state-of-the-art review considers existing literature on climate change as a contributor to changes in drowning risks globally. Using selected climate change-related risks identified by the World Meteorological Organization and key risks to the Sustainable Development Goals as a framework, we consider the drowning risks associated with heat waves, hydrometeorological hazards, drought and water scarcity, damaged infrastructure, marine ecosystem collapse, displacement, and rising poverty and inequality. Although the degree of atmospheric warming remains uncertain, the impact of climate change on drowning risk is already taking place and can no longer be ignored. Greater evidence characterising the links between drowning and climate change across both high-income and low-income and middle-income contexts is required, and the implementation and evaluation of drowning interventions must reflect climate change risks at a local level, accounting for both geographical variation and the consequences of inequality. Furthermore, collaboration between the injury prevention, disaster risk reduction and climate change mitigation sectors is crucial to both prevent climate change from stalling progress on preventing drowning and further advocate for climate change mitigation as a drowning risk reduction mechanism

Resuscitation of Drowned Persons during the COVID-19 Pandemic: A Consensus Statement

Importance: Resuscitation is a niche example of how the COVID-19 pandemic has affected society in the long term. Those trained in cardiopulmonary resuscitation (CPR) face the dilemma that attempting to save a life may result in their own harm. This is most of all a problem for drowning, where hypoxia is the cause of cardiac arrest and ventilation is the essential first step in reversing the situation. Objective: To develop recommendations for water rescue organizations in providing their rescuers with safe drowning resuscitation procedures during the COVID-19 pandemic. Evidence Review: Two consecutive modified Delphi procedures involving 56 participants from 17 countries with expertise in drowning prevention research, resuscitation, and programming were performed from March 28, 2020, to March 29, 2021. In parallel, PubMed and Google Scholar were searched to identify new emerging evidence relevant to each core element, acknowledge previous studies relevant in the new context, and identify knowledge gaps. Findings: Seven core elements, each with their own specific recommendations, were identified in the initial consensus procedure and were grouped into 4 categories: (1) prevention and mitigation of the risks of becoming infected, (2) resuscitation of drowned persons during the COVID-19 pandemic, (3) organizational responsibilities, and (4) organizations unable to meet the recommended guidelines. The common measures of infection risk mitigation, personal protective equipment, and vaccination are the base of the recommendations. Measures to increase drowning prevention efforts reduce the root cause of the dilemma. Additional infection risk mitigation measures include screening all people entering aquatic facilities, defining criteria for futile resuscitation, and avoiding contact with drowned persons by rescuers with a high-risk profile. Ventilation techniques must balance required skill level, oxygen delivery, infection risk, and costs of equipment and training. Bag-mask ventilation with a high-efficiency particulate air filter by 2 trained rescuers is advised. Major implications for the methods, facilities, and environment of CPR training have been identified, including nonpractical skills to avoid being infected or to infect others. Most of all, the organization is responsible for informing their members about the impact of the COVID-19 pandemic and taking measures that maximize rescuer safety. Research is urgently needed to better understand, develop, and implement strategies to reduce infection transmission during drowning resuscitation. Conclusions and Relevance: This consensus document provides an overview of recommendations for water rescue organizations to improve the safety of their rescuers during the COVID-19 pandemic and balances the competing interests between a potentially lifesaving intervention and risk to the rescuer. The consensus-based recommendations can also serve as an example for other volunteer organizations and altruistic laypeople who may provide resuscitation.. © 2022 American Medical Association. All rights reserved

Turn-turn short circuit fault management in permanent magnet machines

This paper presents a systematic study on turn-turn short circuit fault and ways to manage them to provide a basis for comparison of the various options available. The possible methods to reduce the likelihood of the winding SC fault and the fault mitigation techniques related to such faults are discussed. A Finite Element (FE) analysis of a surface-mount Permanent Magnet (PM) machine under application of different mitigation techniques during a turn-turn fault is presented. Both machine and drive structural adaptations for different fault mitigation techniques are addressed. Amongst the investigated fault mitigation techniques, the most promising solution is identified and validated experimentally. It is shown that the shorting terminal method adopting vertical winding arrangement is an effective method in terms of the implementation, reliability and weight

Integrated motor drives: state of the art and future trends

With increased need for high power density, high efficiency and high temperature capabilities in Aerospace and Automotive applications, Integrated Motor Drives (IMD) offers a potential solution. However, close physical integration of the converter and the machine may also lead to an increase in components temperature. This requires careful mechanical, structural and thermal analysis; and design of the IMD system. This paper reviews existing IMD technologies and their thermal effects on the IMD system. The effects of the power electronics (PE) position on the IMD system and its respective thermal management concepts are also investigated. The challenges faced in designing and manufacturing of an IMD along with the mechanical and structural impacts of close physical integration is also discussed and potential solutions are provided. Potential converter topologies for an IMD like the Matrix converter, 2-level Bridge, 3-level NPC and Multiphase full bridge converters are also reviewed. Wide band gap devices like SiC and GaN and their packaging in power modules for IMDs are also discussed. Power modules components and packaging technologies are also presented

An exploratory trial of the effectiveness of an enhanced consultative approach to delivering speech and language intervention in schools

Background: Increased demand for access to specialist services for providing support to children with speech, language and communication needs prompted a local service review of how best to allocate limited resources. This study arose as a consequence of a wish to evaluate the effectiveness of an enhanced consultative approach to delivering speech and language intervention in local schools.Aims: The purpose was to evaluate an intensive speech and language intervention for children in mainstream schools delivered by specialist teaching assistants.Methods & Procedures: A within-subjects, quasi-experimental exploratory trial was conducted, with each child serving as his or her own control with respect to the primary outcome measure. Thirty-five children between the ages of 4;2 and 6;10 (years; months) received speech and/or language intervention for an average of four 1-hour sessions per week over 10 weeks. The primary outcome measure consisted of change between pre- and post-intervention scores on probe tasks of treated and untreated behaviours summed across the group of children, and maintenance probes of treated behaviours. Secondary outcome measures included standardized tests (Clinical Evaluation of Language Fundamentals PreschoolUK (CELF-P UK); Diagnostic Evaluation of Articulation and Phonology (DEAP)) and questionnaires completed by parents/carers and school staff before and after the intervention period.Outcome & Results: The primary outcome measure showed improvement over the intervention period, with target behaviours showing a significantly larger increase than control behaviours. The gains made on the target behaviours as a result of intervention were sustained when reassessed 312 months later. These findings were replicated on a second set of targets and controls. Significant gains were also observed on CELF-PreschoolUK receptive and expressive language standard scores from pre- to post-intervention. However, DEAP standard scores of speech ability did not increase over the intervention period, although improvements in raw scores were observed. Questionnaires completed before and after intervention showed some significant differences relating to how much the child's speech and language difficulties affected him/her at home and at school.Conclusions & Implications: This exploratory study demonstrates the benefit of an intensive therapy delivered by specialist teaching assistants for remediating speech and language difficulties experienced by young children in mainstream schools. The service delivery model was perceived by professionals as offering an inclusive and effective practice and provides empirical support for using both direct and indirect intervention in the school setting. © 2010 Royal College of Speech & Language Therapists.Link_to_subscribed_fulltex