2,065 research outputs found

    Surface tension implementation for Gensmac 2D

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    In the present work we describe a method which allows the incorporation of surface tension into the GENSMAC2D code. This is achieved on two scales. First on the scale of a cell, the surface tension effects are incorporated into the free surface boundary conditions through the computation of the capillary pressure. The required curvature is estimated by fitting a least square circle to the free surface using the tracking particles in the cell and in its close neighbors. On a sub-cell scale, short wavelength perturbations are filtered out using a local 4-point stencil which is mass conservative. An efficient implementation is obtained through a dual representation of the cell data, using both a matrix representation, for ease at identifying neighbouring cells, and also a tree data structure, which permits the representation of specific groups of cells with additional information pertaining to that group. The resulting code is shown to be robust, and to produce accurate results when compared with exact solutions of selected fluid dynamic problems involving surface tension

    Technology Knowledge Base for Coal Mining: Websites at the University of Wollongong

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    A new web portal “Coal Mine Science and Technology” has been established at the University of Wollongong to provide common access to a series of websites operating from its Information Technology servers. The portal links to three active websites and one that is in the process of development. The currently active websites are: Longwall Mining, Coal Mine Outbursts, and Bord and Pillar Mining websites. The fourth website on Heading Development is currently being prepared. All the active websites are designed with a common format and layout but differ in colour scheme. ACARP has funded the Coal Mine outbursts, and Heading Development websites while the other websites are partly funded by the University of Wollongong (UOW) and partly by the industry. The focus of the websites content has a technical orientation and provides the latest information and technology transfer aimed at the mining industry specifically for Australia and generally world wide. The content of all the websites has a predominantly Australian focus

    On the Use of KPCA to Extract Artifacts in One-Dimensional Biomedical Signals

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    Kernel principal component analysis(KPCA) is a nonlinear projective technique that can be applied to decompose multi-dimensional signals and extract informative features as well as reduce any noise contributions. In this work we extend KPCA to extract and remove artifact-related contributions as well as noise from one-dimensional signal recordings. We introduce an embedding step which transforms the one-dimensional signal into a multi-dimensional vector. The latter is decomposed in feature space to extract artifact related contaminations. We further address the preimage problem and propose an initialization procedure to the fixed-point algorithm which renders it more efficient. Finally we apply KPCA to extract dominant Electrooculogram (EOG) artifacts contaminating Electroencephalogram (EEG) recordings in a frontal channel.info:eu-repo/semantics/publishedVersio

    Weight-Bearing Asymmetry in Individuals Post-Hip Fracture During the Sit to Stand Task

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    Background: Individuals post hip fracture decrease force on the involved limb during sit to stand tasks, creating an asymmetry in vertical ground reaction force. Joint specific differences that underlie asymmetry of the vertical ground reaction force are unknown. The purpose of this study was to compare differences in vertical ground reaction force variables and joint kinetics at the hip and knee in participants post-hip fracture, who were recently discharged from home care physical therapy to controls. Methods: Forty-four community-dwelling older adults, 29 who had a hip fracture and 15 elderly control participant’s completed the sit to stand task on an instrumented chair with 3 force plates. T-tests were used to compare clinical tests (Berg Balance Scale, activity balance confidence and gait speed, isokinetic knee strength) and vertical ground reaction force variables. Two-way analyses of variance compared vertical ground reaction force variables and kinetics at the hip and knee between hip fracture and elderly control groups. Pearson correlation coefficients were used to determine correlations between clinical and vertical ground reaction force variables. Findings: Vertical ground reaction force variables were significantly lower on the involved side for the hip fracture group compared to the uninvolved side and controls. Lower involved side hip and knee moments and power contributed to lower involved side vertical ground reaction force. Vertical ground reaction force variables and strength had moderate to high correlations with clinical measures. Interpretation: Uninvolved side knee movements and powers were the largest contributors to asymmetrical vertical ground reaction force in participants post-hip fracture. The association of vertical ground reaction force variables and clinical measures of function suggesting reducing vertical ground reaction force asymmetry may contribute to higher levels of function post-hip fracture. Functional and strength training should target the involved knee to reduce vertical ground reaction force asymmetry. Background Individuals post hip fracture decrease force on the involved limb during sit to stand tasks, creating an asymmetry in vertical ground reaction force. Joint specific differences that underlie asymmetry of the vertical ground reaction force are unknown. The purpose of this study was to compare differences in vertical ground reaction force variables and joint kinetics at the hip and knee in participants post-hip fracture, who were recently discharged from homecare physical therapy to controls. Methods Forty-four community-dwelling older adults, 29 who had a hip fracture and 15 elderly control participant’s completed the sit to stand task on an instrumented chair with 3 force plates. T-tests were used to compare clinical tests (Berg Balance Scale, activity balance confidence and gait speed, isokinetic knee strength) and vertical ground reaction force variables. Two-way analyses of variance compared vertical ground reaction force variables and kinetics at the hip and knee between hip fracture and elderly control groups. Pearson correlation coefficients were used to determine correlations between clinical and vertical ground reaction force variables. Findings Vertical ground reaction force variables were significantly lower on the involved side for the hip fracture group compared to the uninvolved side and controls. Lower involved side hip and knee moments and power contributed to lower involved side vertical ground reaction force. Vertical ground reaction force variables and strength had moderate to high correlations with clinical measures. Interpretation Uninvolved side knee moments and powers were the largest contributors to asymmetrical vertical ground reaction force in participants post-hip fracture. The association of vertical ground reaction force variables and clinical measures of function suggesting reducing vertical ground reaction force asymmetry may contribute to higher levels of function post-hip fracture. Functional and strength training should target the involved knee to reduce vertical ground reaction force asymmetry

    Union after multiple anterior cervical fusion 21 cases followed for 1-6 years

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    With a mean follow-up of 3 (1-6) years, we report on 21 patients who underwent multiple level cervical fusion, using autologous iliac crest grafts. Dissectomies were performed in 14 patients and corpectomies in another 7. Instrumentation was used in all patients with corpectomies and in 2 patients who underwent 2-level and 3-level dissectomies. Non-union occurred in 1 patient at 1 level. Graft displacement requiring reoperation was observed in 2 patients with massive corpectomies, in 1 of them as a consequence of trauma. In both patients complete bony fusion was obtained after reoperation and no other complications were observed. We conclude that the success rate with multiple-level fusion is comparable to that of single-level fusion when adequate fixation is achieve

    Lumbosacral arthrodesis using pedicular screws and ringed rods

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    Sixty-one patients who had lumbar instability and chronic low back pain or deformity from nontraumatic lumbar pathologies were studied. In all of them a posterior lumbosacral fusion with CUN (Clinic of the University of Navarre) pedicle rod fixation was used. The mean follow-up period was 36 months (range 26-46 months). The consolidation rate was evaluated according to plain and functional radiographs, and a clinical evaluation was made using an analogue pain scale. The rate of fusion was 93.5%. Neurological complications occurred in 3.3%. The incidence of screw failure was 2.3% of all the screws. No other implant failure occurred. The patients rated their clinical results as 'excellent' in 33.8% of the cases, 'good' in 42.2%, 'fair' in 16.9% and 'poor' in 6.7%. CUN instrumentation is a versatile internal fixation system that has been shown to provide satisfactory stability. Furthermore, the clinical results are comparable to those reported in studies in which the most common hardwares were used

    Toward an understanding of the aqueous solubility of amino acids in the presence of salts : a molecular dynamics simulation study

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    Ion-specific effects on the aqueous solubilities of biomolecules are relevant in many areas of biochemistry and life sciences. However, a general and well-supported molecular picture of the phenomena has not yet been established. In order to contribute to the understanding of the molecular-level interactions governing the behavior of biocompounds in aqueous saline environments, classical molecular dynamics simulations were performed for aqueous solutions of four amino acids (alanine, valine, isoleucine, and 2-aminodecanoic acid), taken as model systems, in the presence of a series of inorganic salts. The MD results reported here provide support for a molecular picture of the salting-in/salting-out mechanism based on the presence/absence of interactions between the anions and the nonpolar moieties of the amino acids. These results are in good qualitative agreement with experimental solubilities and allow for a theoretical interpretation of the available data
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