THE ANALYSIS OF GAIT IN INDIVIDUALS WITH TRANSFEMORAL AMPUTATION USING A BIONIC KNEE DESIGN: A CASE STUDY

Walking is the body´s natural means of moving from one location to another. It is also the most convenient means of traveling short distances (Perry, 1992). Approximately 4500 new amputations of lower extremities are performed annually in the Czech Republic. Worldwide, 200 – 500 million major amputations are performed each year. Major limb amputations of lower extremities account for approximately 85% of all cases of amputations (Ellis, 2005). The loss of a lower extremity causes the inability to walk without a prosthetic aid. Biomechanics has an important place in the multidisciplinary team, which is essential for the complex care of amputees (Janura, Svoboda, Kozakova, & Birgusova, 2006). New prosthetic designs may enable people with transfemoral amputation perform sports (running) activities in the future. However, it is necessary to master walking with a prosthesis first. The aim of our study is to describe the selected biomechanical parameters of gait in patients with a two-year experience with a bionic knee

THE ANALYSIS OF GAIT IN INDIVIDUALS WITH TRANSFEMORAL AMPUTATION USING A BIONIC KNEE DESIGN: A CASE STUDY

Walking is the body´s natural means of moving from one location to another. It is also the most convenient means of traveling short distances (Perry, 1992). Approximately 4500 new amputations of lower extremities are performed annually in the Czech Republic. Worldwide, 200 – 500 million major amputations are performed each year. Major limb amputations of lower extremities account for approximately 85% of all cases of amputations (Ellis, 2005). The loss of a lower extremity causes the inability to walk without a prosthetic aid. Biomechanics has an important place in the multidisciplinary team, which is essential for the complex care of amputees (Janura, Svoboda, Kozakova, & Birgusova, 2006). New prosthetic designs may enable people with transfemoral amputation perform sports (running) activities in the future. However, it is necessary to master walking with a prosthesis first. The aim of our study is to describe the selected biomechanical parameters of gait in patients with a two-year experience with a bionic knee

Mass Transport Study of Combined Gas Phase and Surface Diffusion in Porous Glass Membrane

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The influence of hand positions on biomechanical injury risk factors at the wrist joint during the round-off skills in female gymnastics

The aim of this study was to examine the biomechanical injury risk factors at the wrist, including joint kinetics, kinematics and stiffness in the first and second contact limb for parallel and T-shape round-off (RO) techniques. Seven international-level female gymnasts performed 10 trials of the RO to back handspring with parallel and T-shape hand positions. Synchronised kinematic (3D motion analysis system; 247 Hz) and kinetic (two force plates; 1235 Hz) data were collected for each trial. A two-way repeated measure analysis of variance (ANOVA) assessed differences in the kinematic and kinetic parameters between the techniques for each contact limb. The main findings highlighted that in both the RO techniques, the second contact limb wrist joint is exposed to higher mechanical loads than the first contact limb demonstrated by increased axial compression force and loading rate. In the parallel technique, the second contact limb wrist joint is exposed to higher axial compression load. Differences between wrist joint kinetics highlight that the T-shape technique may potentially lead to reducing these bio-physical loads and consequently protect the second contact limb wrist joint from overload and biological failure. Highlighting the biomechanical risk factors facilitates the process of technique selection making more objective and safe

The impact and significance of tephra deposition on a Holocene forest environment in the North Cascades, Washington, USA.

© 2016 Elsevier Ltd. High-resolution palaeoecological analyses (stratigraphy, tephra geochemistry, radiocarbon dating, pollen and ordination) were used to reconstruct a Holocene vegetation history of a watershed in the Pacific Northwest of America to evaluate the effects and duration of tephra deposition on a forest environment and the significance of these effects compared to long-term trends. Three tephra deposits were detected and evaluated: MLF-T158 and MLC-T324 from the climactic eruption of Mount Mazama, MLC-T480 from a Late Pleistocene eruption of Mount Mazama and MLC-T485 from a Glacier Peak eruption. Records were examined from both the centre and fringe of the basin to elucidate regional and local effects. The significance of tephra impacts independent of underlying long-term trends was confirmed using partial redundancy analysis. Tephra deposition from the climactic eruption of Mount Mazama approximately 7600 cal. years BP caused a significant local impact, reflected in the fringe location by changes to open habitat vegetation (Cyperaceae and Poaceae) and changes in aquatic macrophytes (Myriophyllum spicatum, Potamogeton, Equisetum and the alga Pediastrum). There was no significant impact of the climactic Mazama tephra or other tephras detected on the pollen record of the central core. Changes in this core are potentially climate driven. Overall, significant tephra fall was demonstrated through high resolution analyses indicating a local effect on the terrestrial and aquatic environment, but there was no significant impact on the regional forest dependent of underlying environmental changes

Adsorption, Gas Phase Transport and Surface Diffusion in Porous Glass Membranes

Increasing attention is currently given to the development and application of inorganic membranes due to their high thermal stability and relatively high chemical stability. There is a great interest in applying inorganic membranes not only for separation but also in combination with chemical reactions. In this context the understanding of mass transfer rates is essential for their successful application and for the development of new membranes with improved performance. The present work is focused on a quantitative study of the mass transfer of inert and adsorbable gas mixtures through tubular porous Vycor glass. Transient diffusion experiments are performed based on substituting an enclosed gas via the membrane by another gas [1]. For this pressure responses between a closed outer volume and an open inner volume are observed with elapsed time for inert-inert, inert-adsorbable and adsorbable-adsorbable gas mixtures. For the observed pressure responses of the adsorbable gas mixtures, obviously a strong asymmetry between two reverse exchange experiments is found instead of the symmetry found for exchanging inert gas mixtures. The observed data are analyzed based on the Dusty Gas Model for the qualification of gas phase diffusion [2] and the generalized Stefan-Maxwell theory for the description of surface diffusion [3]. The model parameters for adsorbable gas mixtures can be determined from measurements for inert-inert and inert-adsorbable gas systems. The calculated results show a systematic disagreement with the observations if the simple competitive Langmuir equation is applied to describe the adsorption equilibria. The competitive adsorption equilibrium is found to have strong influence on the extend of surface diffusion. Thus, reliable competitive adsorption isotherms are required for accurate predictions of the mass transfer. Experimental investigations devoted to determine the required isotherms are carried out using a volumetric method. Surprisingly, the observed amount adsorbed of C3H8 in a 1:1 mixture with CO2 is very similar to that for the single component. Instead, for CO2 adsorption there is the expected competition in the mixture compared to single component adsorption. Further work is currently focused on quantifying the observed adsorption equilibria and on understanding and analyzing the transient diffusion experiments performed. Thus, this project aims to contribute to understand better surface diffusion of adsorbable gases in porous membranes. References: [1] A. Tuchlenski, P. Uchytil and A. Seidel-Morgenstern, An Experimental Study of Combined Gas Phase and Surface Diffusion in Porous Glass, Journal of Membrane Science, 140 (1998) 165. [2] E. A. Mason, A. P. Malinauskas, Gas Transport in Porous Media: The Dusty Gas Model, Elsevier, Amsterdam, 1983. [3] R. Krishna, Problems and Pitfalls in the Use of the Fick Formulation for Intraparticle Diffusion, Chem. Eng. Sci., 48 (1993) 845

Single component and competitive adsorption of propane, carbon dioxide and butane on Vycor glass

Equilibrium of gas phase adsorption on Vycor glass has been investigated. Adsorption isotherms for propane, carbon dioxide and butane as pure gases, binary mixtures and ternary mixtures were determined experimentally as a function of temperature using a volumetric method. The single-component isotherms were described with the Langmuir and Freundlich equations. Additionally, a second order isotherm based on statistical thermodynamics and an isotherm equation based on vacancy solution theory taking into account real phase behavior were used for fitting single-component equilibrium data. In order to describe the measured partial isotherms for binary mixtures, at first simple extensions of the single-component isotherm models were used, i.e., the conventional competitive Langmuir model and a multi-Freundlich equation based on the ideal adsorbed solution theory (IAS). Since these two simple isotherm models failed to represent the unusual competitive behavior observed, three model extensions using additional mixture parameters were applied, i.e., two modified multi-Langmuir equations based on: (a) statistical thermodynamics and (b) vacancy solution theory and a modified multi-Freundlich IAS model correcting spreading pressure uncertainties. These three model equations were found to be capable to describe the observed behavior better. Finally, the measured partial adsorption equilibrium data of the ternary system were correlated based on the extended equations using the determined additional binary parameters. The results obtained reveal the difficulty to predict accurately multi-component adsorption equilibria. Copyright © 2007 Elsevier Ltd All rights reserved

Stérilisation par plasma (mécanismes d'interphase impliqués dans l'inactivation des spores bactériennes traitées par les effluents chimiques d'une décharge couronne)

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Ionic liquid membranes for carbon dioxide-methane separation

The transport of carbon dioxide and methane in polymer containing ionic liquid was studied by a dynamic gas permeation method. Poly(vinylidene fluoride-co-hexafluoropropylene) polymeric membrane (Viton) and two ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [hmim][Tf(2)N]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [emim][Tf(2)N]) were used for preparation of ionic liquid membranes (ILM) with different ionic liquid amounts (from 0 to 80 wt%). For the better understanding of transport mechanism through ionic liquid membranes it is very useful to know also transport properties of pure ionic liquids and pure polymeric material. The gas transport through pure ionic liquid was determined indirectly, by means of the gas transport measurement through two special types of membranes: "sandwich arrangement" and "support arrangement". The dependencies of the separation factor and gas fluxes on the ionic liquid amounts in ionic liquid membranes were determined. The gas permeability increased with the ionic liquid [emim][Tf(2)N] content in the membrane, the permeability for the membranes with [hmim][Tf(2)N] exhibits the maximum for IL concentration of 70 wt%. Ideal separation factor CO(2)/CH(4) was low for small contents of ILs in membranes (0-15 wt%), around 7 for [emim][Tf(2)N] and 8 for [hmim][Tf(2)N] but for higher contents (30-75 wt%) it was approximately constant, 15 for [emimj[Tf(2)N] and 12 for [hmim][Tf(2)N]. Very interesting is the comparison of carbon dioxide permeability, it increases in the series: polymer, ionic liquid and ionic liquid membrane. Although the transport properties values of ILM were expected to be in the middle of the ionic liquid and the polymer from which were formed, surprisingly the obtained transport properties of ILM are much better than those for the pure components. For example, the carbon dioxide permeability for the ionic liquid membrane with 70 wt% of [hmim][Tf(2)N] is almost thousand times higher than for the pure polymer, and hundred times higher than for the ionic liquid. This fact indicates that the mechanism of the transport in ionic liquid membranes has to be different from the transport mechanisms in an ionic liquid. An explanation could be that "new transport pores" are created between polymer chains and an ionic liquid. (C) 2011 Elsevier BM. All rights reserved