30,424 research outputs found

    Finite element modelling of material deformation and damage by tension under cyclic bending and compression test

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    Material deformation is determined by strain and stress states resulted from loading conditions applied on the material during the manufacturing process. Different testing methods, for example, uniaxial tensile test and dome test have been used to predict material deformation behavior during the manufacturing processes. However, under a complex deformation mode, materials display distinct deformation behavior. In double side incremental forming (DSIF) process, it has been widely acknowledged that the material deformation consists of stretching, bending, shearing, compression with cyclic loading. This leads to a significant material formability enhancement comparing to conventional sheet metal forming processes. This phenomenon cannot be explained by using the currently available testing methods because the complexity of the DSIF process prohibits a direct investigation of the influence of individual deformation modes. To simplify the loading conditions and to investigate their individual and interactive effects contributing to the formability enhancement in DSIF, in this study, a novel testing method of Tension under Cyclic Bending and Compression (TCBC) is proposed, through which the effect of stretching, bending, compression and cyclic loading can be independently evaluated. A finite element (FE) damage modelling of the TCBC test was developed by incorporating the shear-modified Gurson-Tvergaard-Needleman (GTN) model into the Abaqus/Explicit solver. The results showed that the damage accumulation in the material was suppressed due to the localized and cyclic material deformation. An enhanced material formability was obtained by using the FE damage modelling and the periodical accumulation of the damage showed that the TCBC test could be a possible representation of the material deformation in DSIF

    Generalized wordlength patterns and strength

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    Xu and Wu (2001) defined the \emph{generalized wordlength pattern} (A1,...,Ak)(A_1, ..., A_k) of an arbitrary fractional factorial design (or orthogonal array) on kk factors. They gave a coding-theoretic proof of the property that the design has strength tt if and only if A1=...=At=0A_1 = ... = A_t = 0. The quantities AiA_i are defined in terms of characters of cyclic groups, and so one might seek a direct character-theoretic proof of this result. We give such a proof, in which the specific group structure (such as cyclicity) plays essentially no role. Nonabelian groups can be used if the counting function of the design satisfies one assumption, as illustrated by a couple of examples

    Residents' Dissatisfaction and All-Cause Mortality. Evidence from 74 European Cities

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    Background: About 2/3 of the Europeans reside in cities. Thus, we must expand our knowledge on how city characteristics affect health and well-being. Perceptions about cities' resources and functioning might be related with health, as they capture subjective experiences of the residents. We characterized the health status of 74 European cities, using all-cause mortality as indicator, and investigated the association of mortality with residents' dissatisfaction with key domains of urban living. Methods: We considered 74 European cities from 29 countries. Aggregated data on residents' dissatisfaction was obtained from the Flash Eurobarometer, Quality of life in European cities (2004–2015). For each city a global dissatisfaction score and a dissatisfaction score by domain (environment, social, economic, healthcare, and infrastructures/services) were calculated. Data on mortality and population was obtained from the Eurostat. Standardized Mortality Ratios, SMR, and 95% Confidence Intervals (95% CI) were calculated. The association between dissatisfaction scores and SMR was estimated using Generalized Linear Models. Results: SMR varied markedly (range: 73.2–146.5), being highest in Eastern Europe and lowest in the South and Western European cities. Residents' dissatisfaction levels also varied greatly. We found a significant association between city SMR and residents' dissatisfaction with healthcare (β = 0.334; IC 95% 0.030–0.639) and social environment (β = 0.239; IC 95% 0.015–0.464). No significant association was found with the dissatisfaction scores related with the physical and economic environment and the infrastructures/services. Conclusions: We found a significant association between city levels of mortality and residents' dissatisfaction with certain urban features, suggesting subjective assessments can be also used to comprehend urban health.This study was funded by FEDER through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology—FCT (Portuguese Ministry of Science, Technology, and Higher Education) under the Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (POCI-01-0145-FEDER-006862; Ref. UID/DTP/04750/2013); and the Postdoc grant SFRH/BPD/97015/2013 (SF), co-funded by the FCT and the POPH/FSE Program

    Needle Tip Force Estimation using an OCT Fiber and a Fused convGRU-CNN Architecture

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    Needle insertion is common during minimally invasive interventions such as biopsy or brachytherapy. During soft tissue needle insertion, forces acting at the needle tip cause tissue deformation and needle deflection. Accurate needle tip force measurement provides information on needle-tissue interaction and helps detecting and compensating potential misplacement. For this purpose we introduce an image-based needle tip force estimation method using an optical fiber imaging the deformation of an epoxy layer below the needle tip over time. For calibration and force estimation, we introduce a novel deep learning-based fused convolutional GRU-CNN model which effectively exploits the spatio-temporal data structure. The needle is easy to manufacture and our model achieves a mean absolute error of 1.76 +- 1.5 mN with a cross-correlation coefficient of 0.9996, clearly outperforming other methods. We test needles with different materials to demonstrate that the approach can be adapted for different sensitivities and force ranges. Furthermore, we validate our approach in an ex-vivo prostate needle insertion scenario.Comment: Accepted for Publication at MICCAI 201

    Sensitive Chemical Compass Assisted by Quantum Criticality

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    The radical-pair-based chemical reaction could be used by birds for the navigation via the geomagnetic direction. An inherent physical mechanism is that the quantum coherent transition from a singlet state to triplet states of the radical pair could response to the weak magnetic field and be sensitive to the direction of such a field and then results in different photopigments in the avian eyes to be sensed. Here, we propose a quantum bionic setup for the ultra-sensitive probe of a weak magnetic field based on the quantum phase transition of the environments of the two electrons in the radical pair. We prove that the yield of the chemical products via the recombination from the singlet state is determined by the Loschmidt echo of the environments with interacting nuclear spins. Thus quantum criticality of environments could enhance the sensitivity of the detection of the weak magnetic field.Comment: 4 pages, 3 figure

    Associations of Body Composition, Maximum Strength, Power Characteristics With Sprinting, Jumping, and Intermittent Endurance Performance in Male Intercollegiate Soccer Players

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    The purpose of this study was to determine the relationships between body composition, strength, power characteristics, sprinting, jumping, and intermittent endurance performance in collegiate male players. Twenty-three players participated (19.7 ± 1.6 yrs; 71.8 ± 7.1 kg; 176.5 ± 5.1 cm). Measurements of interest in body composition included body fat percentage (BF%), lean body mass (LBM), and body mass (BM). Power characteristics were measured with an unloaded squat jump (SJ0) and loaded SJ at 20 kg (SJ20) and 40 kg (SJ40), and unloaded countermovement jump (CMJ0). Power assessments included peak power (PP) and PP allometrically scaled (PPa). Strength characteristics were assessed using isometric mid-thigh pull. Strength assessment included isometric peak force (IPF) and IPF allometrically scaled (IPFa). Performance measures included 10m and 20 m sprint time, CMJ0 jump-height, and Yo-Yo intermittent endurance test level 1 distance. Significant correlations ranging from moderate to very large were found for LBM and CMJ jump height (CM0 JH) (p = 0.01, r = 0.50); BF% and sprint times at 10 m (p = 0.03, r = 0.44) and 20 m (p = 0.02, r = 0.50). PP and PPa from SJ0 and CMJ0 were significantly correlated to 10m sprint time (p \u3c 0.05, r = −0.45 to −0.53) and 20 m sprint time (p \u3c 0.05, r = −0.40 to −0.49). Our findings agree with previous literature in that body composition and power characteristics are directly related to soccer-related performance

    Optimization of six strand tundish based on inclusions motion

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    Inclusion transport and the influence of structural parameters of baffle holes on inclusion removal rate are discussed. The physical modeling experiments give two optimal integrated tundish structural parameters of baffle holes. From the further study of Inclusion trajectories, the tundish should be optimized in the structural parameters of baffle holes in the condition of height 300 mm, angle 30° and diameter 20 mm

    PERBEDAAN PENGARUH LARUTAN PEMBERSIH EKSTRAK BUAH PEPAYA DAN ENZIM PAPAIN DALAM MENGHAMBAT PERTUMBUHAN PLAK DAN S. alpha PADA PLAT SPACE MAINTAINER LEPASAN (Kajian pada anak-anak Yayasan Islamic Centre Bin Baz usia 6-8

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    Akumulasi plak pada plat space maintainer harus selalu dibersihkan agar tidak mengganggu kebersihan jaringan mulut. Selain dengan cara mekanis, pembersihan plat space maintainer bisa dilakukan dengan cara kimia, yaitu dengan larutan pembersih. Penelitian ini bertujuan untuk membandingkan ekstrak buah pepaya dan enzim papain konsentrasi 1% dan 1,5% dalam menghambat pertumbuhan plak dan S. alpha pada plat space maintainer lepasan. Diteliti 10 space maintainer lepasan rahang bawah yang dipakai oleh 10 subyek anak-anak" Yayasan Islamic Center BinBaz. Setelah insersi subyek diinstruksikan untuk membersihkan alat space maintainer 2 kali sehari, saat menyikat gigi pagi dan malam dengan merendam dalam larutan pembersih selama 10 menit. Larutan pembersih yang digunakan untuk perendaman adalah ekstrak buah pepaya 1% dan 1,5% dan enzim papain 1% dan 1,5%. Masing-masing alat direndam selama 7 hari bergantian dengan jeda 7 hari washing period. Data dianalisa dengan anava 2 jalur dan Pairwise comparisons. Rerata penurunan skor plak dan S.alpha terbesar pada larutan ekstrak pepaya 1,5% pada permukaan dalam yaitu 0,42 :f: 0,15 dan 52,10 :f: 8,62. HasH uji anava 2 jalur terdapat perbedaan yang bermakna antara ke-4 jenis laruan pada skor plak (F= 1,785 p=O,OOO)dan S.alpha (F=2,186 p=O,OOO).Analisa Pairwise comparisons menunjukkan penurunan skor plak dan jumlah S. alpha yang bermakna (

    arrayMap 2014: an updated cancer genome resource.

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    Somatic copy number aberrations (CNA) represent a mutation type encountered in the majority of cancer genomes. Here, we present the 2014 edition of arrayMap (http://www.arraymap.org), a publicly accessible collection of pre-processed oncogenomic array data sets and CNA profiles, representing a vast range of human malignancies. Since the initial release, we have enhanced this resource both in content and especially with regard to data mining support. The 2014 release of arrayMap contains more than 64,000 genomic array data sets, representing about 250 tumor diagnoses. Data sets included in arrayMap have been assembled from public repositories as well as additional resources, and integrated by applying custom processing pipelines. Online tools have been upgraded for a more flexible array data visualization, including options for processing user provided, non-public data sets. Data integration has been improved by mapping to multiple editions of the human reference genome, with the majority of the data now being available for the UCSC hg18 as well as GRCh37 versions. The large amount of tumor CNA data in arrayMap can be freely downloaded by users to promote data mining projects, and to explore special events such as chromothripsis-like genome patterns

    Evaluation of deformation stability and fracture mechanism in incremental sheet forming

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    Incremental sheet forming (ISF) is a flexible process for rapid manufacturing of complex sheet metal parts. An advantage of ISF is the improved formability than traditional sheet forming processes such as stamping. A number of fundamental studies have been conducted to investigate the enhanced ISF formability considering the effects such as bending under tension and through thickness shear. To further understand the ISF deformation mechanism and formability enhancement, this work presents a new analytical model which is focused on investigating the deformation stability and its effect on the metal sheet fracture. Based on this new model, the critical strain of deformation instability is obtained. Furthermore, influences of the work-hardening effect and bending effect on the deformation stability are investigated. To validate the analytical model, the fracture occurrence of two aluminum grades, AA1100 and AA5052, are investigated by using ISF experiment. Based on the analytical and experimental investigation, this study has concluded that bending plays a major role on ISF deformation stability. In addition, the ISF fracture depends on both deformation stability and the sheet material's ductility
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