2,394 research outputs found

    Investigation of electrical properties for cantilever-based piezoelectric energy harvester

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    In the present era, the renewable sources of energy, e.g., piezoelectric materials are in great demand. They play a vital role in the field of micro-electromechanical systems, e.g., sensors and actuators. The cantilever-based piezoelectric energy harvesters are very popular because of their high performance and utilization. In this research-work, an energy harvester model based on a cantilever beam with bimorph PZT-5A, having a substrate layer of structural steel, was presented. The proposed energy scavenging system, designed in COMSOL Multiphysics, was applied to analyze the electrical output as a function of excitation frequencies, load resistances and accelerations. Analytical modeling was employed to measure the output voltage and power under pre-defined conditions of acceleration and load resistance. Experimentation was also performed to determine the relationship between independent and output parameters. Energy harvester is capable of producing the maximum power of 1.16 mW at a resonant frequency of 71 Hz under 1g acceleration, having load resistance of 12 k Omega. It was observed that acceleration and output power are directly proportional to each other. Moreover, the investigation conveys that the experimental results are in good agreement with the numerical results. The maximum error obtained between the experimental and numerical investigation was found to equal 4.3%

    Use of the Ilizarov apparatus to improve alignment in proximal humeral fractures treated initially by a unilateral external fixator

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    One of the recommended methods for the management of displaced unstable proximal humeral fractures is the unilateral external fixator. In polytrauma cases this method may be especially useful for the stabilisation of these fractures. However, problems may arise if the fracture is fixed in a malaligned or distracted position. Conversion of the treatment concept to other modalities is difficult because of the problem of pin tract infection. The Ilizarov apparatus provides an useful method in such situations, as it allows distraction, translation and compression without the need for further anaesthesia and additional fixation

    Existence and data dependence of the fixed points of generalized contraction mappings with applications

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    The aim of this paper is to introduce a newtype of generalized multivalued contraction mappings and to present some results regarding fixed points of new class of multivalued contractions. As applications we obtain some basic results in fixed point theory like characterization of metric completeness, data dependence of fixed points and homotopy result. We prove the existence and uniqueness of bounded solution of functional equation arising in dynamic programming. Our results generalize, extend and unify various comparable results in the existing literature.http://link.springer.com/journal/133982016-09-30hb201

    Towards Low Latency and Resource-Efficient FPGA Implementations of the MUSIC Algorithm for Direction of Arrival Estimation

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    The estimation of the Direction of Arrival (DoA) is one of the most critical parameters for target recognition, identification and classification. MUltiple SIgnal Classification (MUSIC) is a powerful technique for DoA estimation. The algorithm requires complex mathematical operations like the computation of the covariance matrix for the input signals, eigenvalue decomposition and signal peak search. All these signal processing operations make real-time and resource-efficient implementation of the MUSIC algorithm on Field Programmable Gate Arrays (FPGAs) a challenge. In this paper, a novel design approach is proposed for the FPGA-implementation of the MUSIC algorithm. This approach enables a significant reduction in both FPGA resources and latency. In more detail, the proposed design enables the estimation of DoA in real-time scenarios in 2μ sec with 30% to 50% fewer resources as compared to existing techniques.The work of Pedro Reviriego was supported in part by the Architecting Intelligent Cost-effective Central Offices to enable 5G Tactile Internet (ACHILLES) through the Spanish Ministry of Economy and Competitivity under Project PID2019-104207RB-I00, in part by the Madrid Government (Comunidad de Madrid-Spain) through the Multiannual Agreement with Universidad Carlos III de Madrid (UC3M) in the line of Excellence of University Professors under Grant EPUC3M21, and in part by the Context of the V Plan Regional de Investigación Científica e Innovación Tecnológica (V PRICIT) (Regional Program of Research and Technological Innovation)

    Prevalence of obesity in patients suffering from migraine

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    Background: Migraine is one of the most common primary headaches, accounting for significant morbidity in patients suffering from it. An association between obesity and migraine has been documented in the past, despite some studies pointing to the contrary. Author’s purpose is to calculate the prevalence of obesity in migraine patients in order to contribute to the existing concepts. A positive correlation could lead to the employment of weight loss interventions in the management of obese patients with migraine.Methods: In this cross-sectional study, 400 patients, recently diagnosed with migraine, attending the Neurology Outpatient Department at the Dr. Ruth KM Pfau Civil Hospital Karachi were enrolled after taking informed consent.  Migraine was diagnosed using International Classification of Headache Disorders III (ICHD III) criteria. Height (meters) and weight (kilograms) were measured and body mass index calculated. This data was kept confidential. The results were tabulated and analyzed using SPSS version 19.  Continuous quantitative data were analyzed using chi square test. A p Value of less than or equal to 0.05 was considered significant.Results: The mean age of enrolled participants was 30.69±6.96 years, 204(51%) were >30 years of age, 159(39.8%) were male and 241(60.3%) were female, mean height was 1.55±0.1 meters, mean weight was 56.26±12.98 kg, and mean duration of migraine was 5.04±2.02 weeks. The prevalence of obesity in patients with migraine was 108 (27%).Conclusions: It was concluded that the prevalence of obesity in patients with migraine was 27%

    Can intersectionality help with understanding and tackling health inequalities? Perspectives of professional stakeholders

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    Background The concept of “intersectionality” is increasingly employed within public health arenas, particularly in North America, and is often heralded as offering great potential to advance health inequalities research and action. Given persistently poor progress towards tackling health inequalities, and recent calls to reframe this agenda in the United Kingdom and Europe, the possible contribution of intersectionality deserves attention. Yet, no existing research has examined professional stakeholder understandings and perspectives on applying intersectionality to this field. Methods In this paper we seek to address that gap, drawing upon a consultation survey and face-to-face workshop (n = 23) undertaken in the United Kingdom. The survey included both researchers (n = 53) and policy and practice professionals (n = 20) with varied roles and levels of engagement in research and evaluation. Topics included familiarity with the term and concept “intersectionality”, relevance to health inequalities work, and issues shaping its uptake. Respondents were also asked to comment on two specific policy suggestions: intersectionally targeting and tailoring interventions, and evaluating the intersectional effects of policies. The workshop aims were to share examples of applying intersectionality within health inequalities research and practice; understand the views of research and practice colleagues on potential contributions and challenges; and identify potential ways to promote intersectional approaches. Results Findings indicated a generally positive response to the concept and a cautiously optimistic assessment that intersectional approaches could be valuable. However, opinions were mixed and various challenges were raised, especially around whether intersectionality research is necessarily critical and transformative and, accordingly, how it should be operationalized methodologically. Nonetheless, there was general agreement that intersectionality is concerned with diverse inequalities and the systems of power that shape them. Conclusions We position intersectionality within the wider context of health inequalities policy and practice, suggesting potential ways forward for the approach in the context of the United Kingdom. The views of policy and practice professionals suggest that intersectionality has far to travel to help counter individualistic narratives and to encourage an approach that is sensitive to subgroup inequalities and the processes that generate them. Examples of promising practice, albeit mostly in North America, suggest that it is possible for intersectionality to gain traction

    Clinical practice guidelines on the management of variceal bleeding

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    Gastroesophageal variceal bleeding occurs in 30 - 50% of patients of liver cirrhosis with portal hypertension, with 20-70% mortality in one year. Therefore, it is essential to screen these patients for varices and prevent first episode of bleeding by treating them with β-blockers or endoscopic variceal band ligation. Ideally, the patients with variceal bleeding should be treated in a unit where the personnel are familiar with the management of such patients and where routine therapeutic interventions can be undertaken. Proper management of such patients include: initial assessment, resuscitation, blood volume replacement, vasoactive agents, prevention of associated complications such as bacterial infections, hepatic encephalopathy, coagulopathy and thrombocytopenia, and specific therapy. Rebleeding occurs in about 60% patients within 2 years of their recovery from first variceal bleeding episode, with 33% mortality. Therefore, it is mandatory that all such patients must be started on combination of β-blockers and band ligation to prevent recurrence of bleeding. Patients who required shunt surgery/TIPSS to control the acute episode do not require further preventive measures. These clinical practice guidelines (CPGs) have been jointly developed by Pakistan Society of Hepatology (PSH) and Pakistan Society of Study of Liver Diseases (PSSLD)

    Multiwall carbon nanotube microcavity arrays

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    Periodic highly dense multi-wall carbon nanotube (MWCNT) arrays can act as photonic materials exhibiting band gaps in the visible regime and beyond terahertz range. MWCNT arrays in square arrangement for nanoscale lattice constants can be configured as a microcavity with predictable resonance frequencies. Here, computational analyses of compact square microcavities (≈0.8 × 0.8 μm2) in MWCNT arrays were demonstrated to obtain enhanced quality factors (≈170-180) and narrow-band resonance peaks. Cavity resonances were rationally designed and optimized (nanotube geometry and cavity size) with finite element method. Series (1 × 2 and 1 × 3) and parallel (2 × 1 and 3 × 1) combinations of microcavities were modeled and resonance modes were analyzed. Higher order MWCNT microcavities showed enhanced resonance modes, which were red shifted with increasing Q-factors. Parallel microcavity geometries were also optimized to obtain narrow-band tunable filtering in low-loss communication windows (810, 1336, and 1558 nm). Compact series and parallel MWCNT microcavity arrays may have applications in optical filters and miniaturized optical communication devices
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