Time filter

Source Type

Beijing, China

Shahaj A.,Nottingham Technology | Garvey S.D.,University of Nottingham
IEEE Transactions on Magnetics | Year: 2011

This paper introduces a magnetic bimorph concept as a means of manipulating magnetostriction in the stator teeth so that components of magnetostrictive force act to cancel out selected components of Maxwell force. This leads to zero net electromagnetic excitation of targeted vibration modes and reduces the vibration and resultant noise emission from the machine. The proposed noise reduction technique is suitable for large electrical machines with vibration modes that experience tooth rocking at natural frequencies within the range of acoustic interest. Experimental and finite-element investigations illustrate that this concept is a practical and low-cost method to implement without degrading the performance of the machine. A finite-element investigation has shown that the contributions to vibration of a large electrical machine from Maxwell forces in the air gap and the magnetostriction effect in the stator iron are comparable. Magnetostriction can act either to reduce or increase the overall modal excitation compared to the excitation of Maxwell forces. © 2006 IEEE. Source

Federici S.,University of Perugia | Meloni F.,University of Perugia | Bracalenti M.,University of Perugia | De Filippis M.L.,Nottingham Technology
NeuroRehabilitation | Year: 2015

OBJECTIVE: This review examines the utility of current active, powered, wearable lower limb exoskeletons as aids to rehabilitation in paraplegic patients with gait disorders resulting from central nervous system lesions. METHOD: The PRISMA guidelines were used to review literature on the use of powered and active lower limb exoskeletons for neurorehabilitative training in paraplegic subjects retrieved in a search of the electronic databases PubMed, EBSCO, Web of Science, Scopus, ProQuest, and Google Scholar. RESULTS:We reviewed 27 studies published between 2001 and 2014, involving a total of 144 participants from the USA, Japan, Germany, Sweden, Israel, Italy, and Spain. Seventy percent of the studies were experimental tests of safety or efficacy and 29% evaluated rehabilitative effectiveness through uncontrolled (22%) or controlled (7%) clinical trials. CONCLUSIONS: Exoskeletons provide a safe and practical method of neurorehabilitation which is not physically exhausting and makes minimal demands on working memory. It is easy to learn to use an exoskeleton and they increase mobility, improve functioning and reduce the risk of secondary injury by reinstating a more normal gait pattern. A limitation of the field is the lack of experimental methods for demonstrating the relative effectiveness of the exoskeleton in comparison with other rehabilitative techniques and technologies. © 2015 - IOS Press and the authors. All rights reserved. Source

Popov A.A.,University of Nottingham | Rowell S.,Nottingham Technology | Meijaard J.P.,University of Twente
Vehicle System Dynamics | Year: 2010

The paper is a review of the state of knowledge and understanding of steering control in motorcycles and of the existing rider models. Motorcycles are well known to have specific instability characteristics, which can detrimentally affect the rider's control, and as such a suitable review of these characteristics is covered in the first instance. Next, early models which mostly treat riding as a regulatory task are considered. A rider applies control based on sensory information available to him/her, predominantly from visual perception of a target path. The review therefore extends to cover also the knowledge and research findings into aspects of road preview control. Here, some more emphasis is placed on recent applications of optimal control and model predictive control to the riding task and the motorcycle-rider interaction. The review concludes with some open questions which naturally present a scope for further study. © 2010 Taylor & Francis. Source

Li S.,Nottingham Technology
International Journal of Mechanical Sciences | Year: 2014

This paper results from a reflection on the problem of finite rotations in plates and shells and its presentation in finite element formulation, a well-attended subject with a wide diversity of treatments, often extremely complicated. For instance, the very topic attracted 3 out of total 15 chapters over 120 out of total 494 pages in a monograph on nonlinear FEA [5]. In another instance, a 71 page journal paper was published [2] specifically on this topic alone. Review papers on this matter can be found in various sources including Appl Mech Rev, (e.g. Ibrahimbegovic, 1997 [8]). No attempt is to be made on reviewing these sophisticated approaches but the present paper will bring answers to questions, if they have ever been asked, such as whether the sophistication in existing approaches is really necessary and whether there is a much simpler and conceptually more direct and accurate approach. A proper re-examination of the existing approaches would reveal a fundamental inconsistency: rigid body rotations have been assumed without reservation to describe the deformations of deformable plates and shells. After re-establishing the consistency based on the very basics of conventional plate and shell theories as a simple reflection, one can conclude surprisingly that the whole issue on 'finite rotations' results from a logic fallacy of faulty generalisation. The so-called 'rotations' should be displacement gradients instead. They can be considered as 'rotations' as conventionally perceived hitherto under the condition of small deformation. Somehow, the concept of 'rotations' got generalised regardless the magnitude of the deformation. Instead of calling the problem as 'finite displacement gradients' as it should be called, a falsely generalised term of 'finite rotations' have been used. Since they were called 'rotations', the definition of those of rigid body kinematics has been taken for granted. Finite displacement gradients should not present any additional problem apart from introducing nonlinear nature into the problem, which can be addressed as a geometrically nonlinear problem in a conventional manner. However, along the line of a falsely generalised concept of finite rigid body rotations, complications have been the norm. The complicated accounts on the 'finite rotation' problem in the literature, which might have enhanced the understanding of rigid body kinematics, are entirely unnecessary as far as the deformable plates and shells are concerned, involving infinitesimal or finite deformations. © 2014 Elsevier Ltd. All rights reserved. Source

Perelman M.,Nottingham Technology | Knight A.,Evicom Ltd
International Journal of Clinical Pharmacology and Therapeutics | Year: 2013

Objective: Fentanyl pectin nasal spray (FPNS) is approved for management of breakthrough pain in cancer. It is available in 100 and 400 μg strength products which allow for doses of 100-800 μg (1 or 2 sprays). Existing titration strategies require a transition from the 100 μg product to the 400 μg product when increasing the dose from 200 to 400 μg. This study assessed the pharmacokinetic (PK) profile of FPNS administered as 4 sprays of 100 μg as an alternate titration strategy. Methods: In this 3-way, crossover study, healthy subjects aged 18-65 years were randomized to receive each of 3 dosages of FPNS (4 x 100 μg, 2 x 100 μg, and 1 x 400 μg). PK samples were collected over 24 hours. Results: Of 22 subjects randomized, 20 were included in the PK analysis. Administration of both 400 μg regimens (4 x 100 μg and 1 x 400 μg) provided greater systemic fentanyl exposure compared with the 200 μg dose (Cmax: 1,748 and 1,485 pg/ml vs. 1,051 pg/ml; AUC0-1h: 1,012 and 944 pgxh/ml vs. 665 pgxh/ml; and tmax: 0.25 hours and 0.50 hours vs. 0.25 hours); fentanyl exposure after 4 x 100 μg and 1 x 400 μg regimens was similar. Adverse events (AEs) were all mild or moderate in intensity; most common AEs were nausea (50%) and headache (23%). AE frequency was similar across treatments without reports of nasal effects. Conclusions: Given that systemic fentanyl exposure from FPNS administered as 4 x 100 μg is similar to that from FPNS as 1 x 400 μg, the 4 x 100 μg regimen provides an alternate titration strategy for patients needing more than 200 μg. This alternate strategy will facilitate a patient's ability to achieve an optimized FPNS regimen and reduce opioid wastage. ©2013 Dustri-Verlag Dr. K. Feistle. Source

Discover hidden collaborations