Monitoring of the training load and recovery parameters in competitive swimmers

Nombreux sont les groupes de recherche qui se sont intéressés, ces dernières années, à la manière de monitorer l'entraînement des sportifs de haut niveau afin d'optimaliser le rendement de ce dernier tout en préservant la santé des athlètes. Un des problèmes cardinaux d'un entraînement sportif mal conduit est le syndrome du surentraînement. La définition du syndrome susmentionné proposée par Kreider et al. est celle qui est actuellement acceptée par le « European College of Sport Science » ainsi que par le « American College of Sports Medicine», à savoir : « An accumulation of training and/or non-training stress resulting in long-term decrement in performance capacity with or without related physiological and psychological signs and symptoms of maladaptation in which restoration of performance capacity may take several weeks or months. » « Une accumulation de stress lié, ou non, à l'entraînement, résultant en une diminution à long terme de la capacité de performance. Cette dernière est associée ou non avec des signes et des symptômes physiologiques et psychologiques d'inadaptation de l'athlète à l'entraînement. La restauration de ladite capacité de performance peut prendre plusieurs semaines ou mois. » Les recommandations actuelles, concernant le monitoring de l'entraînement et la détection précoce du syndrome du surentrainement, préconisent, entre autre, un suivi psychologique à l'aide de questionnaires (tel que le Profile of Mood State (POMS)), un suivi de la charge d'entraînement perçue par l'athlète (p.ex. avec la session rating of perceived exertion (RPE) method selon C. Foster), un suivi des performances des athlètes et des charges d'entraînement effectuées ainsi qu'un suivi des problèmes de santé (blessures et maladies). Le suivi de paramètres sanguins et hormonaux n'est pas recommandé d'une part pour des questions de coût et de faisabilité, d'autre part car la littérature scientifique n'a, jusqu'ici, pas été en mesure de dégager des évidences à ce sujet. A ce jour, peu d'études ont suivi ces paramètres de manière rigoureuse, sur une longue période et chez un nombre d'athlète important. Ceci est précisément le but de notre étude.

Produção de dióxido de manganês eletrolítico para uso em baterias de lítio

The e phase of electrolytic manganese dioxide (EMD) is the structural form most easily converted in the LiMn2O4 spinel used as cathode in lithium batteries. Thus, employing titanium as anode, a study of electrolysis parameters was carried out in order to determine the best conditions to produce an e-EMD suitable for that spinel preparation. The influence of solution temperature (65oC and 90oC) and current density (between 1 mA/cm2 and 17.5 mA/cm2) on the anode potential and the EMD properties was investigated using an aqueous 2.0 mol/L MnSO4 + 0.30 mol/L H2SO4 solution. In any of the electrolysis conditions tested only the e-EMD structure was obtained, but its specific surface area varied with the applied current density and temperature. Drying the e-EMD at temperatures between 60oC and 120oC did not cause any phase changes. To produce a suitable EMD at the highest current density possible without passivation of the titanium anode, the best electrolysis parameters were determined to be 90oC and 15 mA/cm2. The e-EMD thus obtained had a specific surface area (BET) of ca. 65 m2/g.

The summer North Atlantic Oscillation in CMIP3 models and related uncertainties in projected summer drying in Europe

This paper discusses uncertainties in model projections of summer drying in the Euro-Mediterranean region related to errors and uncertainties in the simulation of the summer NAO (SNAO). The SNAO is the leading mode of summer SLP variability in the North Atlantic/European sector and modulates precipitation not only in the vicinity of the SLP dipole (northwest Europe) but also in the Mediterranean region. An analysis of CMIP3 models is conducted to determine the extent to which models reproduce the signature of the SNAO and its impact on precipitation and to assess the role of the SNAO in the projected precipitation reductions. Most models correctly simulate the spatial pattern of the SNAO and the dry anomalies in northwest Europe that accompany the positive phase. The models also capture the concurrent wet conditions in the Mediterranean, but the amplitude of this signal is too weak, especially in the east. This error is related to the poor simulation of the upper-level circulation response to a positive SNAO, namely the observed trough over the Balkans that creates potential instability and favors precipitation. The SNAO is generally projected to trend upwards in CMIP3 models, leading to a consistent signal of precipitation reduction in NW Europe, but the intensity of the trend varies greatly across models, resulting in large uncertainties in the magnitude of the projected drying. In the Mediterranean, because the simulated influence of the SNAO is too weak, no precipitation increase occurs even in the presence of a strong SNAO trend, reducing confidence in these projections.

Energy efficiency parameters in variable speed drives

The main purpose of this thesis is to measure and evaluate how accurately the current energy saving calculation in ABB’s new variable speed drive ACS850 works. The main topic of this thesis is energy-efficiency parameters. At the beginning of this thesis centrifugal pump, squirrel cage motor and variable speed drive, including some equations related to them, are being introduced. Also methods of throttling control and variable speed drive control of centrifugal pumps are being introduced. These subjects are introduced because the energy saving calculation in ACS850 is related to the centrifugal pumps usually driven by squirrel cage motors. The theory also includes short section about specific energy of pumping. Before measurements the current energy saving calculation of ACS850 is being introduced and analyzed. The measurements part includes introduction of measuring equipment, measurement results, summary and analysis of the measurements. At the end of this thesis a proposal for an improvement to the current energy saving calculation is being introduced and few proposals are made for new energy-efficiency parameters, which could be added to variable speed drives. At the end are also thoughts

On the effects of welding parameters on weld quality of plasma arc keyhole welding of structural steels

The possibility and the usefulness of applying plasma keyhole welding to structural steels with different compositions and material thicknesses, and in various welding positions has been examinated. Single pass butt welding with I groove in flat, horizontal vertical and vertical positions and root welding with V , Y and U grooves of thick plate material in flat position have been studied and the welds with high quality has been obtained. The technological conditions for successful welding are presented. The single and interactive effects of welding parameters on weld quality, especially on surface weld defects, geometrical form errors, internal defects and mechanical properties (strength, ductility, impact toughness, hardness and bendability) of weld joint, are presented. Welding parameter combinations providing the best quality welds are also presented.

Swarm Intelligent Selection and Optimization of Machining System Parameters for Microchannel Fabrication in Medical Devices

Current technology trends in medical device industry calls for fabrication of massive arrays of microfeatures such as microchannels on to nonsilicon material substrates with high accuracy, superior precision, and high throughput. Microchannels are typical features used in medical devices for medication dosing into the human body, analyzing DNA arrays or cell cultures. In this study, the capabilities of machining systems for micro-end milling have been evaluated by conducting experiments, regression modeling, and response surface methodology. In machining experiments by using micromilling, arrays of microchannels are fabricated on aluminium and titanium plates, and the feature size and accuracy (width and depth) and surface roughness are measured. Multicriteria decision making for material and process parameters selection for desired accuracy is investigated by using particle swarm optimization (PSO) method, which is an evolutionary computation method inspired by genetic algorithms (GA). Appropriate regression models are utilized within the PSO and optimum selection of micromilling parameters; microchannel feature accuracy and surface roughness are performed. An analysis for optimal micromachining parameters in decision variable space is also conducted. This study demonstrates the advantages of evolutionary computing algorithms in micromilling decision making and process optimization investigations and can be expanded to other applications

The effects of real time control of welding parameters on weld quality in plasma arc keyhole welding

Joints intended for welding frequently show variations in geometry and position, for which it is unfortunately not possible to apply a single set of operating parameters to ensure constant quality. The cause of this difficulty lies in a number of factors, including inaccurate joint preparation and joint fit up, tack welds, as well as thermal distortion of the workpiece. In plasma arc keyhole welding of butt joints, deviations in the gap width may cause weld defects such as an incomplete weld bead, excessive penetration and burn through. Manual adjustment of welding parameters to compensate for variations in the gap width is very difficult, and unsatisfactory weld quality is often obtained. In this study a control system for plasma arc keyhole welding has been developed and used to study the effects of the real time control of welding parameters on gap tolerance during welding of austenitic stainless steel AISI 304L. The welding tests demonstrated the beneficial effect of real time control on weld quality. Compared with welding using constant parameters, the maximum tolerable gap width with an acceptable weld quality was 47% higher when using the real time controlled parameters for a plate thickness of 5 mm. In addition, burn through occurred with significantly larger gap widths when parameters were controlled in real time. Increased gap tolerance enables joints to be prepared and fit up less accurately, saving time and preparation costs for welding. In addition to the control system, a novel technique for back face monitoring is described in this study. The test results showed that the technique could be successfully applied for penetration monitoring when welding non magnetic materials. The results also imply that it is possible to measure the dimensions of the plasma efflux or weld root, and use this information in a feedback control system and, thus, maintain the required weld quality.

The effect of microfibrillated cellulose addition on drying shrinkage and dimensional stability of wood-free paper

Microfibrillated cellulose (MFC) is known to enhance strength properties of paper. Improved strength usually means increased bonding which is strongly connected to dimensional instability of paper. Dimensional instability is due to changes in moisture content of paper; when paper is moistened it expands and when dried, it shrinks. Hygroexpansion is linked to end-use problems and excessive drying shrinkage consumes strength potential. Effective use of materials requires controlling of these phenomena. There isn’t yet data concerning dimensional stability of papers containing MFC which restricts wider use of MFC. Main objective of the work was to evaluate dimensional stability of wood-free paper containing different amounts of MFC. Sheets were dried with different methods to see how drying strains effected on drying shrinkage and hygroexpansion. Also tensile strength was measured to find out the effect of MFC. Results were compared to sheets containing kraft fines and in some test points cationic starch was used alongside with MFC. MFC increased the dimensional instability of freely dried sheets. As the amounts of MFC increased the effects on dimensional stability became more severe. However the fineness of MFC didn’t play any important role. Both hygroexpansion and drying shrinkage were decreased with cationic starch addition. Prevention of drying shrinkage over powered the effects of additives on hygroexpansion. Tensile strength improved up till 7 % addition amount which could be set as the upper limit of MFC addition when paper preparation and tensile strength are concerned.

High pressure compression of filter cakes

The purpose of this thesis was to investigate the compression of filter cakes at high filtration pressures with five different test materials and to compare the energy consumption of high pressure compression with the energy consumption of thermal drying. The secondary target of this study was to investigate the particle deformation of test materials during filtration and compression. Literature part consists of basic theory of filtration and compression and of the basic parameters that influence the filtration process. There is also a brief description about all of the test materials including their properties and their industrial production and processing. Theoretical equations for calculating the energy consumptions of the filtrations at different conditions are also presented. At the beginning of the experiments at experimental part, the basic filtration tests were done with all the five test materials. Filtration tests were made at eight different pressures, from 6 bars up to 100 bars, by using piston press pressure filter. Filtration tests were then repeated by using a cylinder with smaller slurry volume than in the first series of filtration tests. Separate filtration tests were also done for investigating the deformation of solid particles during filtration and for finding the optimal curve for raising the filtration pressure. Energy consumption differences between high pressure filtration and ideal thermal drying process were done partly experimentally and partly by using theoretical calculation equations. By comparing these two water removal methods, the optimal ranges for their use were found considering their energy efficiency. The results of the measurements shows that the filtration rate increased and the moisture content of the filter cakes decreased as the filtration pressure was increased. Also the porosity of the filter cakes mainly decreased when the filtration pressure was increased. Particle deformation during the filtration was observed only with coal particles.

Physicochemical parameters of Amazon Melipona honey

Stingless bees produce a honey that is different from the Apis honey in terms of composition. There aren't enough data to establish quality control parameters for this product, mainly due to lack of research results. The aim of this work is to evaluate some physicochemical parameters that can be used for the characterization and for the quality control of the Meliponinae honey. Four different samples were collected in the Amazon region of Brazil in 2004 (Melipona compressipes manaoense bee and Melipona seminigra merribae bee). Honey analyses were performed as described by the official methods. The mean results were: moisture (30.13%), pH (3.65), acidity (24.57 mEq/kg), water activity (0.75), fructose (31.91%), glucose (29.30%) and sucrose (0.19%). These results reinforce the need for a specific regulation for stingless bee honey. This will only be feasible when enough data is available to establish upper and lower limits for the physicochemical parameters used for quality control.

Microencapsulação do agente quelante sulfoxina em microesferas de quitosana preparadas por spray drying como novo adsorvente para íons metálicos

In this work, a new adsorbent was prepared by microencapsulation of sulfoxine into chitosan microspheres by the spray drying technique. The new adsorbent was characterized by Raman spectroscopy, scanning electron microscopy and microanalysis of energy dispersive X-rays. The Cu(II) adsorption was studied as a function of pH, time and concentration. The optimum pH was found to be 6.0. The kinetic and equilibrium data showed that the adsorption process followed the pseudo second-order kinetic model and the Langmuir isotherm model over the entire concentration range. An increase of 8.0% in the maximum adsorption capacity of the adsorbent (53.8 mg g-1) was observed as compared to chitosan glutaraldehyde cross-linked microspheres.

Imobilização da lacase em micropartículas de quitosana obtidas por spray drying e usadas na construção de biossensores

Biosensors based on laccase immobilized on microparticles of chitosan crosslinked with tripolyphosphate (biosensor I) and glyoxal (biosensor II) obtained by spray drying for the determinations of rutin in pharmaceutical formulations were developed. Under optimized operational conditions (pH 4.0, frequency of 30 Hz, pulse amplitude of 40 mV and scan increment of 2.0 mV) two analytical curves were obtained for both biosensors showing a detection limit of 6.2x10-8 mol L-1 for biosensor (I) and 2.0x10-8 mol L-1 for biosensor (II). The recovery of rutin from pharmaceutical sample ranged from 90.7 to 105.0% and the lifetime of these biosensors were 4 months (at least 400 determinations).

An expeditious and consistent procedure for tetrahydrofuran (THF) drying and deoxygenation by the still apparatus

Despite the availability of alternative methods for drying tetrahydrofuran (THF), the use of the still apparatus, wherein a THF solution containing Na-bezophenone ketyl is heated to reflux, remains widespread. We herein propose a set of procedures to solve the problems usually faced in applying this drying technique. Moreover, a discussion is made on the chemical knowledge underlying such procedures. Safety and economy issues concerned with the operation of the THF still apparatus are also discussed.

Construção de uma câmara para monitoramento in situ do processo de secagem de geis e sólidos porosos

The present work deals with the design and construction of an equipment for studying the drying process of gels and solids. The equipment was built using mainly a commercial oven and others peripherals for programmed control of temperature, humidity and data acquisition. The system allows the in situ monitoring of the gel drying, registering the weight loss, and the shrinkage of sample and the oven temperatures. This set of allowed parameters makes possible to establish the main steps involved in the drying of meso and nanostructured porous materials.