Assessment of cooling methods for increased power density in electrical machines

A comprehensive thermal analysis of three different electrical machines is presented, with a view of identifying design aspects that can be exploited to achieve higher power density. A review of some novel cooling methods is initially made. Following this, the stator and rotor thermal resistance paths of the three selected machines are created and the individual components of each resistance path mathematically analysed to identify the parts of the machines that provide greatest potential to reduce stator and rotor temperatures. This is verified with a Design of Experiments analysis on the thermal resistance models of each. Finally, a different novel cooling method is applied to the model of each machine, demonstrating the typical temperature reductions that can be achieved

The Impact of Municipal Mergers on Local Public Spending:Evidence from Remote-Sensing Data

How are resources distributed when administrative units merge? We take advantage of recent, large-scale municipal mergers in Japan to systematically study the impact of municipal mergers within merged municipalities and, in particular, what politicians do when their districts and constituencies suddenly change. We argue that when rural and sparsely populated municipalities merge with more urban and densely populated municipalities, residents of the former are likely to see a reduced share of public spending because they lost political leverage through the merger. Our empirical analyses detect changes in public spending before and after the municipal mergers with remote sensing data, which allows for flexible units of analysis and enables us to proxy for spending within merged municipalities. Overall, our results show that politicians tend to reduce benefits allocated to areas where there are a small number of voters, while increasing the allocation to more populous areas. The micro-foundation of our argument is also corroborated by survey data. The finding suggests that, all things being equal, the quantity rather than quality of electorates matters for politicians immediately after political units change

An assessment of financial viability of recycled carbon fibre in automotive applications

Carbon fibre (CF) recycling has been demonstrated to achieve reductions in environmental impacts compared to virgin CF production, but there is limited understanding of the financial viability of recycling and reutilisation of recycled CF (rCF). In this work, cost analysis and identification of market opportunities for rCF are performed by evaluating the cost of recycling, composite manufacture, and applications in automotive industry. Cost impacts of using rCF as a substitute for conventional materials and competitor lightweight materials are assessed over the full life cycle, including in-use implications. Recovery of CF can be achieved at $5/kg and less across a wide range of process parameters, approximately 15% of the cost of producing virgin carbon fibre. The life cycle cost results show that rCF composites, especially aligned rCF composites, give substantial cost reductions relative to virgin CF composites and even steel and aluminium

Thanks for the memories: exploring city tourism experiences via social media reviews

This study uses online reviews to explore memorable tourism experiences of tourists visiting different city attractions. Seeking to identify a collection of themes and concepts reflecting tourists' memorable experiences during their attraction visits, this study reveals the most shared tourism memories in cognitive-emotive-behavioral themes. By developing a matrix that categorizes tourist city attractions based on an ideographic approach, the study also argues that there are different types of tourist memorable experiences at different types of attractions (i.e., human-marker, nature-sight and human-sight tourist attractions). The findings extend previous understanding of the research in tourism experience and attractions by analyzing 156,986 TripAdvisor tourist reviews of the top ten most popular tourist attractions in London. This study also provides recommendations for destination management organizations and various city tourism stakeholders to plan, market and manage city tourism products and services

Salmonella flagellin activates NAIP/NLRC4 and canonical NLRP3 inflammasomes in human macrophages

Infection of human macrophages with Salmonella enterica serovar Typhimurium (S. Typhimurium) leads to inflammasome activation. Inflammasomes are multi-protein complexes facilitating caspase–1 activation and subsequent gasdermin D-mediated cell death and interleukin–1β and interleukin–18 cytokine release. The NAIP/NLRC4 inflammasome is activated by multiple bacterial protein ligands including flagellin from the flagellum and the needle protein PrgI from the S. Typhimurium type III secretion system. Here we show that transfected ultrapure flagellin from S. Typhimurium induced cell death and cytokine secretion in THP–1 cells and primary human monocyte-derived macrophages (hMDM). In THP–1 cells, NAIP/NLRC4 and NLRP3 played redundant roles in inflammasome activation during infection with S. Typhimurium. Knock-out of NAIP or NLRC4 in THP–1 cells revealed that flagellin, but not PrgI, now activated the NLRP3 inflammasome through a ROS- and/or cathepsin-dependent mechanism that was independent of caspase–4/5 activity. In conclusion, our data suggest that NLRP3 can be activated by flagellin to act as a “safety net” to maintain inflammasome activation under conditions of suboptimal NAIP/NLRC4 activation, as observed in THP–1 cells, possibly explaining the redundant role of NLRP3 and NAIP/NLRC4 during S. Typhimurium infection.Wellcome Trus

High speed solid rotor permanent magnet machines: concept and design

This paper proposes a novel solid rotor topology for an Interior Permanent Magnet (IPM) machine, adopted in this case for an aircraft starter-generator design. The key challenge in the design is to satisfy two operating conditions which are: a high torque at start and a high speed at cruise. Conventional IPM topologies which are highly capable of extended field weakening are found to be limited at high speed due to structural constraints associated with the rotor material. To adopt the IPM concept for high speed operation, it is proposed to adopt a rotor constructed from semi-magnetic stainless steel, which has a higher yield strength than laminated silicon steel. To maintain minimal stress levels and also minimize the resultant eddy current losses due to the lack of laminations, different approaches are considered and studied. Finally, to achieve a better tradeoff between the structural and electromagnetic constraints, a novel slitted approach is implemented on the rotor. The proposed rotor topology is verified using electromagnetic, static structural and dynamic structural Finite Element (FE) analyses. An experiment is performed to confirm the feasibility of the proposed rotor. It is shown that the proposed solid rotor concept for an IPM fulfils the design requirements whilst satisfying the structural, thermal and magnetic limitations

Production of Lightning NO(x) and its Vertical Distribution Calculated from 3-D Cloud-scale Chemical Transport Model Simulations

A 3-D cloud scale chemical transport model that includes a parameterized source of lightning NO(x), based on observed flash rates has been used to simulate six midlatitude and subtropical thunderstorms observed during four field projects. Production per intracloud (P(sub IC) and cloud-to-ground (P(sub CG)) flash is estimated by assuming various values of P(sub IC) and P(sub CG) for each storm and determining which production scenario yields NO(x) mixing ratios that compare most favorably with in-cloud aircraft observations. We obtain a mean P(sub CG) value of 500 moles NO (7 kg N) per flash. The results of this analysis also suggest that on average, P(sub IC) may be nearly equal to P(sub CG), which is contrary to the common assumption that intracloud flashes are significantly less productive of NO than are cloud-to-ground flashes. This study also presents vertical profiles of the mass of lightning NO(x), after convection based on 3-D cloud-scale model simulations. The results suggest that following convection, a large percentage of lightning NO(x), remains in the middle and upper troposphere where it originated, while only a small percentage is found near the surface. The results of this work differ from profiles calculated from 2-D cloud-scale model simulations with a simpler lightning parameterization that were peaked near the surface and in the upper troposphere (referred to as a "C-shaped" profile). The new model results (a backward C-shaped profile) suggest that chemical transport models that assume a C-shaped vertical profile of lightning NO(x) mass may place too much mass neat the surface and too little in the middle troposphere

Lean participative process improvement : outcomes and obstacles in trauma orthopaedics

To examine the effectiveness of a “systems” approach using Lean methodology to improve surgical care, as part of a programme of studies investigating possible synergy between improvement approaches. Setting A controlled before-after study using the orthopaedic trauma theatre of a UK Trust hospital as the active site and an elective orthopaedic theatre in the same Trust as control. Participants All staff involved in surgical procedures in both theatres. Interventions A one-day “lean” training course delivered by an experienced specialist team was followed by support and assistance in developing a 6 month improvement project. Clinical staff selected the subjects for improvement and designed the improvements. Outcome Measures We compared technical and non-technical team performance in theatre using WHO checklist compliance evaluation, “glitch count” and Oxford NOTECHS II in a sample of directly observed operations, and patient outcome (length of stay, complications and readmissions) for all patients. We collected observational data for 3 months and clinical data for 6 months before and after the intervention period. We compared changes in measures using 2-way analysis of variance. Results We studied 576 cases before and 465 after intervention, observing the operation in 38 and 41 cases respectively. We found no significant changes in team performance or patient outcome measures. The intervention theatre staff focused their efforts on improving first patient arrival time, which improved by 20 minutes after intervention. Conclusions This version of “lean” system improvement did not improve measured safety processes or outcomes. The study highlighted an important tension between promoting staff ownership and providing direction, which needs to be managed in “lean” projects. Space and time for staff to conduct improvement activities are important for success

Computational fluid dynamics modelling of an entire synchronous generator for improved thermal management

This study is the first in a series dedicated to investigating the airflow and thermal management of electrical machines. Owing to the temperature dependent resistive losses in the machine's windings, any improvement in cooling provides a direct reduction in losses and an increase in efficiency. This study focuses on the airflow which is intrinsically linked to the thermal behaviour of the machine as well as the windage power consumed to drive the air through the machine. A full computational fluid dynamics (CFD) model has been used to analyse the airflow around all major components of the machine. Results have been experimentally validated and investigated. At synchronous speed the experimentally tested mass flow rate and windage torque were under predicted by 4% and 7%, respectively, by the CFD. A break-down of torque by component shows that the fan consumes approximately 87% of the windage torque

London, you have a problem with women: trust towards the police in England

Following a series of high-profile incidents of violence against women by serving London Metropolitan Police Officers, questions of standards and the public’s confidence in policing are in the spotlight. Over a fifteen-month period between July 2022 and September 2023 using monthly surveys of representative English samples, this study confirms that women, in general, are more trusting in the police than men. This, however, does not hold true in London. Out of nine regions in England, London is the only region where women’s overall trust in the police is lower than men. Lower levels of trust in the police among women in London hold when controls for age, income, political environment and crime levels are considered. In line with existing literature that considers women being more sensitive to cues about trustworthiness, the concerning incidents of sexual violence by police officers against women are likely to further erode trust in police in the capital, which already ranks last among England’s nine regions in citizen trust of the police