2,567 research outputs found

    Self organizing fuzzy sliding mode controller for the position control of a permanent magnet synchronous motor drive

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    AbstractIn this paper, a self organizing fuzzy sliding mode controller (SOFSMC) which emulates the fuzzy controller with gain auto-tuning is proposed for a permanent magnet synchronous motor (PMSM) drive. The proposed controller is used for the position control of the PMSM drive. The performance and robustness of the control system is tested for nonlinear motor load torque disturbance and parameter variations. It has a novel gain self organizing strategy in response to the transient or tracking responses requirement. To illustrate the performance of the proposed controller, the simulation studies are presented separately for the SOFSMC and the fuzzy controller with gain auto-tuning. The results are compared with each other and discussed in detail. Simulation results showing the effectiveness of the proposed control system are confirmed under the different position changes

    Analysis of Interior and Exterior Environment Construction of Library Building and Rationalization Proposal

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    With increasingly fierce social competition, people need to constantly acquire knowledge to keep pace with the times. Thus, more and more people to resort to the library for learning, which is bound to have a huge impact on the construction and development of the library. To better reflect the function of the library, and make library provide more services, it is needed to systematically research the construction of interior and exterior environment of the library building in both reconstruction and expansion projects in the library. In this paper, the three major principles which should be followed in the construction of interior and exterior environment of the library building, namely perfect combination of applicability and artistry, giving prominence to culture and atmosphere, and green design and sustainable development. Secondly, countermeasures for problems (lack of parking space, design of the rest room, and so on) in the process of interior and exterior environment construction of a library building are put forward. Besides, deep discussions on measures for interior and exterior environment construction of a library building also are made. Thus, this paper is of certain reference value

    Search for vector-like leptons at a Muon Collider

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    A feasibility study is performed for searching vector-like leptons at a muon collider, in the context of the "4321 model", an ultraviolet-complete model with rich collider phenomenology together with potential to explain recent existing some B physics measurements or anomalies. In this paper, we perform a Monte Carlo study with various machine learning techniques, and examine the projected sensitivity on vector-like leptons over a wide mass range at a TeV-scale muon collider. We find that a 3 TeV muon collider with only 10/fb of data can already be sensitive to cover the mass range of a vector-like lepton up to 1450 GeV.Comment: CPC Published Versio

    The Pursuit of K: Reflections on the Current State-of-the-Art in Stress Intensity Factor Solutions for Practical Aerospace Applications

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    The elastic stress intensity factor (SIF, commonly denoted as K) is the foundation of practical fracture mechanics (FM) analysis for aircraft structures. This single parameter describes the first-order effects of stress magnitude and distribution as well as the geometry of both structure/component and crack. Hence, the calculation of K is often the most significant step in fatigue analysis based on FM. This presentation will provide several reflections on the current state-of-the-art in SIF solution methods used for practical aerospace applications, including a brief historical perspective, descriptions of some recent and ongoing advances, and comments on some remaining challenges. Newman and Raju made significant early contributions to practical structural analysis by developing closed-form SIF equations for surface and corner cracks in simplified geometries, often based on empirical fits of finite element (FE) solutions. Those solutions (and others like them) were sometimes revised as new analyses were conducted or limitations discovered. The foundational solutions have exhibited striking longevity, despite the relatively "coarse" FE models employed many decades ago. However, in recent years, the accumulation of different generations of solutions for the same nominal geometry has led to some confusion (which solution is correct?), and steady increases in computational capabilities have facilitated the discovery of inaccuracies in some (not all!) of the legacy solutions. Some examples of problems and solutions are presented and discussed, including the challenge of maintaining consistency with legacy design applications. As computational power has increased, the prospect of calculating large numbers of SIF solutions for specific complex geometries with advanced numerical methods has grown more attractive. Fawaz and Andersson, for example, have been generating literally millions of new SIF solutions for different combinations of multiple cracks under simplified loading schemes using p-version FE methods. These data are invaluable, but questions remain about their practical use, because the tabular databases of key results needed to support practical life analysis can occupy gigabytes of storage for only a few classes of geometries. The prospect of using such advanced numerical methods to calculate in real time only those K solutions actually needed to support a specific crack growth analysis is also tempting, but the stark reality is that the computational cost is still so high that the approach is not practical except for specific, critical application problems. Some thoughts are offered about alternative paradigms. Compounding approaches are some of the earliest building blocks of SIF development for more complex geometries. These approaches are especially attractive because of their very low computational cost and their conceptual robustness; they are, in some ways, an intriguing contrast and complement to the brute-force numerical methods. In recent years, researchers at NRC-Canada have published remarkable results showing how compounding approaches can be used to generate accurate solutions for very difficult problems. Examples are provided of some successes--and some limitations--using this approach. These closed-form, tabulated numerical, and compounding approaches have typically been used for simple remote loading with simple load paths to the crack. However, many significant cracks occur in complex stress gradient fields. This is a job for weight function (WF) methods, where the arbitrary stress distribution on the crack plane in the corresponding uncracked body (typically determined using FE methods) is used to determine K. Several significant recent advances in WF methods and solutions are highlighted here. Fueled by advanced 3D numerical methods, many new solutions have been generated for classic geometries such as surface and corner cracks with wide ranges of geometrical validity. A new WF formulation has also be developed for part-through cracks considering the arbitrary stress gradients in all directions in the crack plane (so-called bivariant solutions). Basic WF methods have recently been combined with analytical expressions for crack plane stresses to develop a large family of accurate SIF solutions for corner, surface, and through cracks at internal or external notches with very wide ranges of shapes, sizes, acuities, and offsets. Finally, WF solutions are much faster than FE or boundary element solutions, but can still be much slower than simple closed-form solutions, especially for bivariant solutions that can require 2D numerical integration. Novel pre-integration and dynamic tabular methods have been developed that substantially increase the speed of these advanced WF solutions. The practical utility of advanced SIF methods, including both WF and direct numerical methods, is greatly enhanced if the FM life analysis can be directly and efficiently linked with digital models of the actual structure or component (e.g., FE models for stress analysis). Two recent advances of this type will be described. One approach directly interfaces the FM life analysis with the FE model of the uncracked component (including stress results). Through a powerful graphical user interface, simplified FM life models can be constructed (and visualized) directly on the component model, with the computer collecting the geometry and stress gradient information needed for the life calculation. An even more powerful paradigm uses expert logic to automatically build an optimum simple fracture model at any and every desired location in the component model, perform the life calculation, and even generate fatigue crack growth life contour maps, all with minimal user intervention. This paradigm has also been extended to the automatic calculation of fracture risk, considering uncertainty or variability in key input parameters such as initial crack size or location. Another new integrated approach links the engineering life analysis, the component model, and a 3D numerical fracture analysis built with the same component model to generate a table of SIF values at a specific location that can then be employed efficiently to perform the life calculation. Some attention must be given to verification and validation (V&V) issues and challenges: how good are these SIF solutions, how good is good enough, and does anyone believe the life answer? It is important to think critically about the different sources of error or uncertainty and to perform V&V in a hierarchal, building-block manner. Some accuracy issues for SIF solutions, for example, may actually involve independent material behavior issues, such as constraint loss effects for crack fronts near component surfaces, and can be a source of confusion. Recommendations are proposed for improved V&V approaches. This presentation will briefly but critically survey the range of issues and advances mentioned above, with a particular view towards assembling an integrated approach that combines different methods to create practical tools for real-world design and analysis problems. Examples will be selectively drawn from the recent literature, from recent enhancements in the NASGRO and DARWIN computer codes, and from previously unpublished researc

    Relationship between IL-10 gene -819C/T polymorphism and the risk of inflammatory bowel disease: A meta-analysis

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    Background: The -819C/T polymorphism in interleukin 10 (IL-10) gene has been reported to be associated with inflammatory bowel disease (IBD) ,but the previous results are conflicting.Materials and methods: The present study aimed at investigating the association between this polymorphism and risk of IBD using a meta-analysis.PubMed,Web of Science,EMBASE,google scholar and China National Knowledge Infrastructure (CNKI) databases were systematically searched to identify relevant publications from their inception to April 2016.Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using fixed- or random-effects models.Results: A total of 7 case-control studies containing 1890 patients and 2929 controls were enrolled into this meta-analysis, and our results showed no association between IL-10 gene -819C/T polymorphism and IBD risk(TT vs. CC:OR=0.81,95%CI 0.64- 1.04;CT vs. CC:OR=0.92,95%CI 0.81-1.05; Dominant model: OR=0.90,95%CI 0.80-1.02; Recessive model: OR=0.84,95%CI 0.66-1.06). In a subgroup analysis by nationality, the -819C/T polymorphism was not associated with IBD in both Asians and Caucasians. In the subgroup analysis stratified by IBD type, significant association was found in Crohn’s disease(CD)(CT vs. CC:OR=0.68,95%CI 0.48-0.97).Conclusion: In summary, the present meta-analysis suggests that the IL-10 gene -819C/T polymorphism may be associated with CD risk.Keywords: Interleukin 10, -819C/T polymorphism, inflammatory bowel diseaseDue to errors in the previous PDF especially in the 'Cite as' authors names, the PDF fulltext has been reloaded. This information is now correct

    A Group-Based Trust Model in Peer-to- Peer Environment

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    Abstract. The open and anonymous nature of peer-to-peer system makes it easy to be attacked and abused by some malicious nodes, so it is very important to establish a perfect trust mechanism in peer-to-peer environment. In this paper, we propose a novel group-based trust model in which the trust relationships between entities are divided into trust relationship in group and trust relationship between groups. This model deals with these two kinds of trust relationships in the different way and improves trust value calculation method. The model can get more real trust value at the small price, and the advantages of the model are simple structure and high reliability

    Expression of miR-126 and its potential function in coronary artery disease

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    Objective: This study aimed to explore the role of miR-126 in coronary artery disease (CAD) patients and the potential gene targets of miR-126 in atherosclerosis.Methodology: A total of 60 CAD patients and 25 healthy control subjects were recruited in this study. Among the 60 CAD patients, 18 cases were diagnosed of stable angina pectoris (SAP), 20 were diagnosed of unstable angina pectoris (UAP) and 22 were diagnosed of acute myocardial infarction (AMI). Plasma miR-126 levels from both groups of participants were analyzed by real-time quantitative PCR. ELISA was used to measure plasma level of placenta growth factor (PLGF).Results: The results showed that the miR-126 expression was significantly down-regulated in the circulation of CAD patients compared with control subjects (P<0.01). Plasma PLGF level was significantly upregulated in patients with unstable angina pectoris and acute myocardial infarction (AMI) compared with controls (both P<0.01) the miR-126 expression in AMI was significantly associated with PLGF.Conclusion: miR-126 may serve as a novel biomarker for CAD.Keywords: miR-126; PLGF; PCR; coronary artery disease; atherosclerosi

    Comparative transcriptomics in Yersinia pestis: a global view of environmental modulation of gene expression

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    <p>Abstract</p> <p>Background</p> <p>Environmental modulation of gene expression in <it>Yersinia pestis </it>is critical for its life style and pathogenesis. Using cDNA microarray technology, we have analyzed the global gene expression of this deadly pathogen when grown under different stress conditions <it>in vitro</it>.</p> <p>Results</p> <p>To provide us with a comprehensive view of environmental modulation of global gene expression in <it>Y. pestis</it>, we have analyzed the gene expression profiles of 25 different stress conditions. Almost all known virulence genes of <it>Y. pestis </it>were differentially regulated under multiple environmental perturbations. Clustering enabled us to functionally classify co-expressed genes, including some uncharacterized genes. Collections of operons were predicted from the microarray data, and some of these were confirmed by reverse-transcription polymerase chain reaction (RT-PCR). Several regulatory DNA motifs, probably recognized by the regulatory protein Fur, PurR, or Fnr, were predicted from the clustered genes, and a Fur binding site in the corresponding promoter regions was verified by electrophoretic mobility shift assay (EMSA).</p> <p>Conclusion</p> <p>The comparative transcriptomics analysis we present here not only benefits our understanding of the molecular determinants of pathogenesis and cellular regulatory circuits in <it>Y. pestis</it>, it also serves as a basis for integrating increasing volumes of microarray data using existing methods.</p

    Combined use of venetoclax and azacitidine in treatment of acute myeloid leukemia complicated with disseminated Fusarium infection: a case report

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    Acute myeloid leukemia (AML) is a malignant clonal disease originating from hematopoietic stem/progenitor cells. Chemotherapy is the main treatment. If not effectively treated after 2 courses of standard treatment, these patients can be diagnosed with refractory AML. In this article, a case of refractory AML complicated with disseminated Fusarium infection receiving combined treatment of venetoclax and azacitidine was reported. The patient was diagnosed with AML (M5a) with DNMT3A, IDH2 and BCOR mutations, classified in the moderate group. Standard dose of IA regimen (deoxydaunorubicin + cytarabine) was ineffective, and additional homoharringtonine induction therapy remained ineffective. Subsequently, combined use of venetoclax and azacitidine was adopted and the severity of disease was alleviated. Complete remission was achieved after three cycles of venetoclax combined with azacitidine consolidation therapy. After the first chemotherapy, the patient presented with recurrent fever, purple induration with central necrosis in the upper and lower limbs, and visible subcutaneous liquid mass. Pathological examination suggested Fusarium infection. After amphotericin B combined with voriconazole as antifungal therapy, disseminated Fusarium infection was effectively controlled. This case prompts that combined use of venetoclax and azacitidine yields high remission rate in the treatment of refractory AML. Disseminated Fusarium infection is a rare fatal complication in AML patients after chemotherapy. Early diagnosis and effective antifungal treatment are effective interventions to improve the survival rate of patients

    Structure basis for the unique specificity of medaka enteropeptidase light chain

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    Thermal stresses concern not renewed type of stresses, that is once having liberated, they cannot accumulate more. The estimation of purely thermoelastic contribution to a lithosphere stress state gives the additional information, allowing to predict the danger connected with such natural factors, as seismic and volcanic activity. Some theoretical thermoelastic problems for the geological environment of a difficult outline with non-uniform thermophysical characteristics are considered. The decision is received on the basis of a numerical finite elements method. Influence of the model fixation, the geometrical factor and boundary conditions on distribution of thermal stresses and dislocation is investigated. Computing experiments have shown, that the size of the maximum thermal stresses reaches 500 bar. The maximum values of vertical dislocation are reached by 90 m, and horizontal — 50 m. Neutral plane position are precisely defined. Термоупругие напряжения относятся к невозобновляемому типу напряжений, то есть, однажды высвободившись, напряжения не могут накапливаться вновь. Расчет термоупругого вклада в напряженное состояние литосферы дает дополнительную информацию, позволяющую оценить опасность, связанную с такими природными явлениями, как сейсмичность и вулканическая активность. Рассмотрено несколько теоретических моделей для геологической среды сложного очертания с неоднородными теплофизическими характеристиками. Решение получено на основе численного метода конечных элементов. Исследовано влияние «закрепления» модели, геометрического фактора, неоднородных граничных условий на распределение термоупругих напряжений и перемещений. Вычислительные эксперименты показали, что величина максимальных термоупругих напряжений достигает 500 б. Максимальные величины вертикальных перемещений не превышают 90 м, горизонтальных — 50 м. Положение нейтральной плоскости определяется точно. На основі методу скінченних елементів отримано детальний розподіл термопружних напружень і переміщень для неоднорідного геологічного середовища. Досліджено взаємний вплив геометрії середовища й неоднорідних граничних умов на розподіл термопружних напружень та переміщень
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