Analytical Model to Calculate Radial Forces in Permanent-Magnet Synchronous Machines

There are three principal sources of noise and vibration in electrical machines: electromagnetic sources, mechanical sources, and aerodynamic sources. Nowadays, one of the major advantages of permanent-magnet synchronous machines is their torque density. This density is achieved through a high magnetic flux density in the air gap, which is achieved through hard magnets. Unfortunately, in these machines, electromagnetic forces have been identified as the main source of vibration and noise, and high magnetic flux densities make these vibrations and noises more significant. With the aim of better understanding the relationship between electromagnetic forces and design variables, this article, which is the continuation of previous work, firstly describes a study of the sources of magnetic forces in permanent-magnet synchronous machines. Subsequently, an analytical model for the computation of the radial forces originating from electromagnetic sources in permanent-magnet synchronous machines is stated. This model analyzes the forces on both the rotor surface and the base of the stator tooth. The analytical results were corroborated through simulations using the finite element method (FEM) and also by experimental tests performed over two prototypes. The results achieved by the analytical model show good agreement with both FEM results and experimental measurements

Influence of manufacturing tolerances and eccentricities on the unbalanced magnetic pull in permanent magnet synchronous motors

Eccentricity is an inevitable fault in electric motors and hence its diagnosis is an important topic. Thus, the influence of static and dynamic eccentricities on the harmonics of the frequency spectra of the unbalanced magnetic pull is analyzed.In this study, dimensional tolerances of the rotor and the stator are also considered. All parts have dimensional tolerances in their designs and their real magnitudes vary to some extent from the theoretical values after the manufacturing process. Thanks to the finite element simulations, verified with experimental results, it is observed that the deviations originated by the manufacturing tolerances produce changes in the amplitudes of some harmonics and also additional and characteristic harmonics in the frequency spectra of the unbalanced magnetic pull. These are not negligible and must be taken into account when robust eccentricity detection procedures are defined. Otherwise, harmonics originated by tolerances and by eccentricities can be misidentified

Misoprostol for small bowel ulcers in patients with obscure bleeding taking aspirin and non-steroidal anti-inflammatory drugs (MASTERS): a randomised, double-blind, placebo-controlled, phase 3 trial

Background: The incidence of obscure gastrointestinal bleeding, which originates from the small bowel and is mainly associated with the use of aspirin and non-steroidal anti-inflammatory drugs (NSAIDs), is rising. We assessed the efficacy and safety of misoprostol for the treatment of small bowel ulcers and erosions in patients taking low-dose aspirin or NSAIDs with obscure gastrointestinal bleeding. Methods: In this randomised, double-blind, placebo-controlled, phase 3 trial, we recruited patients (aged ≥18 years) with small bowel ulcers who were taking low-dose aspirin, NSAIDs, or both for a minimum of 4 weeks, at University Hospital Crosshouse (Kilmarnock, UK). Eligible patients had evidence of obscure gastrointestinal bleeding (iron deficiency anaemia, a decrease in haemoglobin concentration of ≥20 × 103 mg/L, or positive faecal occult blood test) and normal upper endoscopy and colonoscopy. Patients were randomly assigned (1:1) using an interactive voice response system to receive 200 μg oral misoprostol or placebo four times daily for 8 weeks. Patients, investigators, and assessors were masked to treatment allocation. The primary endpoint was the complete healing of small bowel ulcers and erosions, assessed by video capsule endoscopy after 8 weeks of treatment. Primary analysis was by modified intention to treat, which included all randomised patients who received at least one dose of study treatment. Safety was assessed in the same population. The trial is registered with ClinicalTrials.gov, number NCT02202967. Findings: Between Jan 7, 2016, and Oct 11, 2017, we randomly allocated 104 eligible patients: 52 to receive misoprostol and 52 to receive placebo. Two patients allocated to misoprostol were later found to meet one of the exclusion criteria, thus 50 randomly assigned patients in the misoprostol group and 52 patients in the placebo group received at least one dose of study treatment. Complete healing of small bowel ulcers and erosions was noted at week 8 in 27 (54%) of 50 patients in the misoprostol group and nine (17%) of 52 patients in the placebo group (percentage difference 36·7%, 95% CI 19·5–53·9; p=0·0002). Adverse events occurred in 23 (46%) of 50 patients in the misoprostol group and 22 (42%) of 52 patients in the placebo group. The most common adverse events were abdominal pain (ten [20%] in the misoprostol group vs 13 [25%] in the placebo group), nausea or vomiting (nine [18%] vs seven [13%]), and diarrhoea (11 [22%] vs six [12%]). Four (8%) of 50 patients in the misoprostol group had severe adverse events, compared with none in the placebo group. No serious adverse events were reported. Interpretation: Misoprostol is effective for the treatment of small bowel ulcers and erosions in patients using low-dose aspirin and NSAIDs. Misoprostol might represent a pharmacological treatment option for lesions causing obscure gastrointestinal bleeding that is associated with aspirin and NSAIDs, but its use should be balanced against the risk of side-effects

Development of Tools to Calculate the Vibroacoustic Performance of Electrical Machines in Lift Installations

Improper operation of the traction machine of a lift installation causes energy waste, vibrations and noise. The design of the machine must be optimum if energy efficiency and comfort specifications have to be satisfied. The vibrations and noise frequency spectra of electrical machines present manifest peaks at certain frequencies, multiples of the fundamental electrical frequency, that depend on the machine topology and its rotation velocity. Changes in its topology or in its mechanical properties (geometry, size, materials…) must be done in order to reduce the magnitude of peaks at certain excitation frequencies or to locate the excitation frequencies far from the natural frequencies of the structure or the lift installation. Machine designers need tools to calculate their vibroacoustic response once a certain design has been proposed, so they can modify it before a prototype is built in case the response is not acceptable. Numerical and analytical models to calculate the vibroacoustic response of electrical machines have been developed and experimentally validated. In this paper, the authors summarise the state of the art in modelling the vibroacoustic performance of electrical machines, provide some guidelines regarding the values to be assigned to the machine componets, and show some of the results obtained in their research work

Optimum Slot and Pole Design for Vibration Reduction in Permanent Magnet Synchronous Motors

Permanent Magnet Synchronous Motors (PMSMs) are increasingly being used and are required to satisfy noise and vibration specifications. Thus, it is necessary to develop design guidelines for electric motors that consider vibration response as a key output of the design. This work shows the influence of the main design parameters regarding PMSMs: the number of slots and the number of poles. First, the influence of the number of slots in the natural frequencies is analysed by Finite Element calculations, which are experimentally verified. Then, the analytical calculation of the vibration response is explained. This is applied for several combinations of the number of slots and the number of poles, and the results are compared. Considering the analytical development, a procedure to choose the most adequate combination of the number of slots and poles is proposed. The analytical predictions are validated according to experimental measurements in two machines

Machine learning model of acoustic signatures: towards digitalised thermal spray manufacturing.

Thermal spraying, an important industrial surface manufacturing process in sectors such as aerospace, energy and biomedical, remains a skill intensive process often involving multiple trial runs impacting the yield. The core research challenge in digitalisation of the thermal spraying process lies in instrumenting the manufacturing platform, as the process includes harsh conditions such as UV rays, high-plasma temperatures, dusty chemical environments and inaccessibility of the spray booth. This paper introduces a novel application of machine learning to the acoustic emission spectra of thermal spraying. By transitioning from the amplitude-time domain to a Fourier-transformed frequency-time domain, it is possible to predict anomalies in real-time - a crucial step towards sustainable material and manufacturing digitalisation. Our experimental results also indicate that this method is suitable for industrial applications, by generating useful data that can be used to develop Visual Geometry Group (VGG) transfer learning models to overcome the traditional limitations of convoluted neural networks (CNN)

The Grizzly, April 17, 2008

Owen Gingerich Discusses Religion and Evolution at UC • Breakaway Presents P.S. We\u27ve Missed You at UC! • Kennedy Speaks • Achievement Gap: An Issue Left Behind? • All Dogs Go to Heaven: Review of Black Lab Bistro • UC Theater Dances in an Irish Spring • Opinions: Want Change? Vote Obama; Elitists in Government? Yes Please! • A Swingin\u27 Season for UC Tennishttps://digitalcommons.ursinus.edu/grizzlynews/1762/thumbnail.jp

Syndromic surveillance: two decades experience of sustainable systems – its people not just data!

Syndromic surveillance is a form of surveillance that generates information for public health action by collecting, analysing and interpreting routine health-related data on symptoms and clinical signs reported by patients and clinicians rather than being based on microbiologically or clinically confirmed cases. In England, a suite of national real-time syndromic surveillance systems (SSS) have been developed over the last 20 years, utilising data from a variety of health care settings (a telehealth triage system, general practice and emergency departments). The real-time systems in England have been used for early detection (e.g. seasonal influenza), for situational awareness (e.g. describing the size and demographics of the impact of a heatwave) and for reassurance of lack of impact on population health of mass gatherings (e.g. the London 2012 Olympic and Paralympic Games).We highlight the lessons learnt from running SSS, for nearly two decades, and propose questions and issues still to be addressed. We feel that syndromic surveillance is an example of the use of ‘big data’, but contend that the focus for sustainable and useful systems should be on the added value of such systems and the importance of people working together to maximise the value for the public health of syndromic surveillance services

Mutations in Known Monogenic High Bone Mass Loci Only Explain a Small Proportion of High Bone Mass Cases.

High bone mass (HBM) can be an incidental clinical finding; however, monogenic HBM disorders (eg, LRP5 or SOST mutations) are rare. We aimed to determine to what extent HBM is explained by mutations in known HBM genes. A total of 258 unrelated HBM cases were identified from a review of 335,115 DXA scans from 13 UK centers. Cases were assessed clinically and underwent sequencing of known anabolic HBM loci: LRP5 (exons 2, 3, 4), LRP4 (exons 25, 26), SOST (exons 1, 2, and the van Buchem's disease [VBD] 52-kb intronic deletion 3'). Family members were assessed for HBM segregation with identified variants. Three-dimensional protein models were constructed for identified variants. Two novel missense LRP5 HBM mutations ([c.518C>T; p.Thr173Met], [c.796C>T; p.Arg266Cys]) were identified, plus three previously reported missense LRP5 mutations ([c.593A>G; p.Asn198Ser], [c.724G>A; p.Ala242Thr], [c.266A>G; p.Gln89Arg]), associated with HBM in 11 adults from seven families. Individuals with LRP5 HBM (∼prevalence 5/100,000) displayed a variable phenotype of skeletal dysplasia with increased trabecular BMD and cortical thickness on HRpQCT, and gynoid fat mass accumulation on DXA, compared with both non-LRP5 HBM and controls. One mostly asymptomatic woman carried a novel heterozygous nonsense SOST mutation (c.530C>A; p.Ser177X) predicted to prematurely truncate sclerostin. Protein modeling suggests the severity of the LRP5-HBM phenotype corresponds to the degree of protein disruption and the consequent effect on SOST-LRP5 binding. We predict p.Asn198Ser and p.Ala242Thr directly disrupt SOST binding; both correspond to severe HBM phenotypes (BMD Z-scores +3.1 to +12.2, inability to float). Less disruptive structural alterations predicted from p.Arg266Cys, p.Thr173Met, and p.Gln89Arg were associated with less severe phenotypes (Z-scores +2.4 to +6.2, ability to float). In conclusion, although mutations in known HBM loci may be asymptomatic, they only account for a very small proportion (∼3%) of HBM individuals, suggesting the great majority are explained by either unknown monogenic causes or polygenic inheritance.This study was supported by The Wellcome Trust and NIHR CRN (portfolio number 5163). CLG was funded by a Wellcome Trust Clinical Research Training Fellowship (080280/Z/06/Z), the EU 7th Framework Programme under grant agreement number 247642 (GEoCoDE), a British Geriatric Society travel grant, and is now funded by Arthritis Research UK (grant ref 20000). SH acknowledges Arthritis Research UK support (grant ref 19580). KESP acknowledges the support of Cambridge NIHR Biomedical Research Centre. KAW is supported by the core programme of the MRC Nutrition and Bone Health group at MRC Human Nutrition Research, funded by the UK Medical Research Council (Grant code U10590371). EM acknowledges support of the Sheffield Teaching Hospitals Foundation Trust Clinical Research Facility. The SGC is a registered charity (no. 1097737) that receives funds from AbbVie, Bayer, Boehringer Ingelheim, Genome Canada (Ontario Genomics Institute OGI- 055), GlaxoSmithKline, Janssen, Lilly Canada, Novartis Research Foundation, Ontario Ministry of Economic Development & Innovation, Pfizer, Takeda, and Wellcome Trust (092809/Z/10/Z).This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/jbmr.270