A global human walking model with real-time kinematic personification

This paper presents a human walking model built from experimental data based on a wide range of normalized velocities. The model is structured on two levels. On the first level, global spatial and temporal characteristics (normalized length and step duration) are generated. On the second level, a set of parameterized trajectories produce both the position of the body in space and the internal body configuration. This is performed for a standard structure and an average configuration of the human body.The experimental context corresponding to the model is extended by allowing a continuous variation of global spatial and temporal parameters according to the motion rendition expected by the animator. The model is based on a simple kinematic approach designed to keep the intrinsic dynamic characteristics of the experimental model. Such an approach also allows a personification of the walking action in an interactive real-time context in most cases. A correction automata of such motion is then proposed.     

A graphical pascal extension based on graphical types

The goal of this paper is to present a graphical Pascal extension, named MIRA. This extension gives the user the means of defining and using specific graphical types. A complete vector arithmetic has been developed and a new structured type has been introduced: the figure type. Instructions to create and delete figures are discussed and it is shown how the graphical types can be used as other Pascal types. The implementation is carried out by a portable Pascal preprocessor.     

Relationship between gelation and morphology of rubber-modified epoxy resins

The addition of both a solid and a liquid rubber to an epoxy resin has been shown to strongly increase the toughness of the material. Moreover, it is well known that toughening depends on the morphology of the system, which, in turn, depends on the cure conditions. In the present work the morphologies of epoxy resins modified with mixtures of solid and liquid rubbers have been studied through transmission electron microscopy. An investigation of the influence of the elastomers and of the gel time on the morphology of the hardened material was carried out. Gel times were evaluated, through rheological measurements, at different cure temperatures.     

Reliability Analysis of a System Subject to Partial and Catastrophic Failures

This note considers a system which is subject to both partial and catastrophic failures. A Markov process, continuous in time and with three discrete states is used to demonstrate the effect of the throw-away maintenance philosophy on reliability.     

Interdisciplinary hydrogeological investigations

Traditionally, the responsibility for hydrogeological investigations in developing countries falls on governmental institutions, accustomed more to the management and handling of the resource rather than to its research. At the present time, the characteristics of developing countries restrict the possibility of applying and developing contemporary techniques and methodologies in the field of hydrogeology to universities or high‐level educational institutions, which do not necessarily maintain communication with the authorities in charge of the supply and administration of water. As an example of this research policy the Aquifer Development Project, carried out by the Geophysics Institute of the National University of México (UNAM), is presented.     

Nanocomposite polymer electrolyte based on whisker or microfibrils polyoxyethylene nanocomposites

Nanocomposite polymer electrolytes composed of high molecular weight poly(oxyethylene) PEO as a matrix, LiTFSI as lithium salt and ramie, cotton and sisal whiskers with high aspect ratio and sisal microfibrils (MF), as reinforcing phase were prepared by casting-evaporation. The morphology of the composite electrolytes was investigated by scanning electron microscopy and their thermal behavior (characteristic temperatures, degradation temperature) were investigated by thermogravimetric analysis and differential scanning calorimetry.Nanocomposite electrolytes based on PEO reinforced by whiskers and MF sisal exhibited very high mechanical performance with a storage modulus of 160 MPa at high temperature. A weak decrease of the ionic conductivity was observed with the incorporation of 6 wt% of whiskers. The addition of microfibrils involved a larger decrease of the conductivity. This difference may be associated to the more restricted PEO mobility due to the addition of entangled nanofibers.     

Modelling the respiration rate of minimally processed broccoli (Brassica rapa var. sylvestris) for modified atmosphere package design

In this work, the effect of temperature, oxygen and carbon dioxide on the respiration rate of minimally processed broccoli was studied to develop suitable modified atmosphere packaging. Respiration rate was measured at 3, 5, 7, 10, 15 and 20 °C under different gas compositions of O₂ and CO₂ (1%, 5%, 10%, 15% and 21% of O₂ with the balance N₂, a mixture of 10% and 20% of carbon dioxide with the balance air and a mixture at 3% of O₂ and 15% of CO₂ with the balance N₂). As expected, temperature was the most influential factor on respiration rate, for all atmospheres tested: increasing the temperature from 3 to 20 °C resulted, for air‐stored samples, in a 84% change in oxygen respiration rate, whereas at constant temperature, the respiration rate decreased by 35% with lowering the O₂ concentration from 21% to 1% and by 44% with increasing the CO₂ concentration from 0% to 20%. The Michaelis and Menten competitive model with maximum respiration rate varying against temperature with an Arrhenius equation accurately described the influence of gas composition and temperature on the respiration rate of minimally processed broccoli, and it was used to design a suitable package.     

Ionic properties of an organic–inorganic sol–gel hybrid based on polydimethylsiloxane and tetraethoxysilane doped with sodium dodecyl sulfate

In this work, we performed impedance spectroscopy measurements of organically modified silicate membranes based on polydimethylsiloxane (PDMS) and tetraethoxysilane (TEOS) with the inclusion of sodium dodecyl sulfate (SDS) at five different concentrations. The results indicated that the conduction in a pure PDMS/TEOS hybrid membrane mainly resulted from a hopping mechanism. The conduction of membranes modified with the addition of SDS increased for SDS concentrations up to 20% and decreased for higher concentrations. This effect was explained on the basis of the porosity of the membranes due to SDS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comparing Two Multi-Criteria Methods for Prioritizing Wetland Restoration and Creation Sites Based on Ecological,Biophysical and Socio-Economic Factors

Wetland restoration has been recognized as a useful tool for improving water quality. Many studies have focused on developing strategies and models to optimize wetland performance. However, some important wetland placement characteristics have not been taken into account. In this research and unlike other studies, we included the social aspect (availability of public lands) as a fundamental factor to locate wetlands. Thus, environmental, biophysical and socio-economic factors were integrated through the comparison of two multi-criteria methods (a suitability model and a greedy algorithm). With nitrate removal as the main goal, the suitability model was applied considering the “terrain slope”, “proximity to watercourses” and “soil permeability”. The greedy algorithm was executed based on the “availability of public lands” and the “wetland restoration project costs”. These factors were chosen based on the Eu Life-CREAMAgua Flumen River project, which was carried out previously in the study area. Both the suitability model and the greedy algorithm provided critical information for siting a wetland and demonstrated the effectiveness of both approaches. By means of this study, we present highly applicable results as they are based on a real project (Eu Life-CREAMAgua Flumen River project), besides proposing and using the social factor as an innovative approach for the wetlands siting. This research and its possible adaptations can be used by decision makers to improve water quality using social and economic criteria, resulting in the efficient implementation of ecological-restoration projects.     

Effect of Sodium Bicarbonate on the Properties of Metronidazole Floating Matrix Tablets

The effect of sodium bicarbonate (SB) on the swelling behavior and the sustained release of floating systems was studied with varied proportions of this excipient and metronidazole. Two polymers with different hydration characteristics, Methocel K4M and Carbopol 971P NF, were used to formulate the matrices. Under in vitro dissolution conditions, the addition of SB to metronidazole sustained-release tablets modifies the matrix hydration volume, increasing at the beginning, reaching a maximum, and then declining. Pure Carbopol matrices show a rapid hydration with a limited further effect of the SB and metronidazole loads. Methocel show a significant increase of the apparent hydration volume due to SB addition with no further notable change due to metronidazole load. Increasing the metronidazole load reduces the floating time of Carbopol matrices while no effect on Methocel matrices could be observed within 8 hours dissolution. Matrices show increasing release constant values (k) as the metronidazole load increases. Methocel matrices release the drug 10% to 15% faster than Carbopol matrices. SB increases the cumulative amount of drug released from Methocel but not that releasing from Carbopol. These results are attributed to the intrinsic polymer properties, the barrier effect of CO₂ bubbles, and the matrix volume expansion produced after addition of SB.