Search

Resumen El principal propósito del presente artículo de investigación, fue comparar dos métodos usados para el diseño y evaluación biomecánica de implantes dentales. El primer método se desarrolló basado en la integración de una técnica imagenológica usada en diagnóstico de imágenes tomográficas, para la reconstrucción de modelos 3D virtuales óseos con herramientas software de ingeniería inversa, articulada al diseño aplicado en ingeniería e ingeniería mecánica aplicada. En el segundo método, la probeta de mandíbula fue modelada en un software CAD (Computer Aided Design) que fue utilizado para el diseño del implante; posteriormente fue realizado la simulación biomecánica estática en un entorno CAE (Computer Aided Engineering), aplicando cargas incrementales de torque de inserción en la interfase hueso implante. Los análisis por simulación en ambos métodos fueron realizados basados en los mismos criterios de evaluación. Se corroboró por simulación los valores de torque de inserción apropiados para mantener una adecuada relación en la interfase hueso implante. Por otra parte los resultados obtenidos por la aplicación de cada método de diseño fueron analizados y comparados para conocer el efecto de la integración de las técnicas imagenológicas apropiadas desde el software Bio CAD y articulado con las tecnologías software CAD CAE. Abstract The main objective of this research work was to make a comparison between two methods used for design and biomechanical assessment of dental implants.. The first method is based on integration of an imaging technique used in diagnosis of tomographic images applied to 3D bone model reconstruction with reverse engineering software tools implemented on engineering applications. In the second method a specimen of jaw modeled in CAD (Computer Aided Design) software used to implant design was implemented, then a static simulation biomechanics was performed in a CAE (Computer Aided Engineering) environment, applying elementary insertion torque loads at the bone-implant interface. Simulations Analysis were performed for both methods, using the same evaluation criteria. Appropriate insertion torque values were confirmed with simulations as appropriate to maintain a proper relationship at the bone-implant interface. The results obtained using each method were analyzed and compared to determine the effect on appropriate integration of BioCAD imaging techniques and articulation with Technologies CAD and CAE.

We thank Rene Cabral for his comments and suggestions on our paper Inequality and minimum wage policy: Not even talking, much less walking in Mexico (2015). It seems to us that although Cabral does identify some omissions in our paper, in general terms he agrees with most of our main conclusions. These are that the high inequality in Mexico is socially and economically inefficient; that it is indispensable to further study the links between inequality and minimum wages in Mexico; that this relationship, as well as the very low levels of minimum wages in Mexico, might have something to do with the less-than-optimal growth records of recent decades; that the chances for the legal delinking ( desvinculacion ) of minimum wages to other non-labor related variables as well as the implementation of a new policy to increase them in a significant and sustainable way in the country ―fiercely opposed by some sectors of the Mexican elite― will depend to a large extent on politics...

Enzymatic transesterification of palm oil with methanol and ethanol was studied. Of the four lipases that were tested in the initial screening, lipase Candida Rugosa (CR) resulted in the highest yield of mono alkyl esters. Lipase CR was further investigated in immobilized form within an activated carbon as support. The activated carbon was prepared by activation physical. Using the immobilized lipase CR, the effects of water and alcohol concentration, enzyme loading and enzyme thermal stability in the transesterification reaction were investigated. The optimal conditions for processing 50 g of palm oil were: 37 °C, 1:14.5 oil/methanol molar ratio, 1.0 g water and 500 mg lipase for the reactions with methanol, 35 °C, 1:15.0 oil/ethanol molar ratio, 1.0 g water, 500 mg lipase for the reactions with ethanol, and 35 °C, 1:10.0 oil/ n -butanol molar ratio, 1.0 g water, 500 mg lipase for the reactions with ethanol. Subject to the optimal conditions, methyl and ethyl esters formation of 70 and 85 mol% in 1 h of reaction were obtained for the immobilized enzyme reactions. The flow microcalorimetry is an important and novel techniques is used in evaluation of biodiesel production.

The book has a strong theoretical foundation with empirical illustrations from diverse Latin American countries. As a whole, it offers a comprehensive exploration of the foundations of the theory of National Innovation Systems. The authors explore the particular problems that many Latin American countries have faced when trying to build innovation systems associated with development strategies, particularly those that take into account social inclusion.

We have analyzed in an interrelated way the main processes that occur in a glow discharge system: generation of the energetic particles that strike the cathode, emission of sputtered and reflected atoms from the cathode, and transport of these particles through the plasma, until their eventual arrival to the substrate. As an output of our calculations we have obtained the radial profiles of the energy and the number of particles that reach the substrate, as a function of the geometrical characteristics and pressure of the discharge. Our results show that the main part of the energy deposited in the substrate comes from the reflected gas atoms, in spite of the larger number of sputtered cathode atoms. © 1999 American Vacuum Society.@S0734-2101~99!02702-5# The aim of this article is to calculate the energy distribu- tion and the number of particles that bombard the substrate in a glow discharge sputtering system, as a function of the radial distance from the cathode-substrate axis. Special em- phasis will be paid to analyze the role played by those gas particles that, after being reflected in the cathode, reach the substrate with high energy, as compared to the sputtered cathode particles. The effects of the discharge pressure, p, and the cathode-substrate distance, d, on the radial profile of energy deposited in the substrate, will be discussed in detail for both the sputtered and the reflected fluxes of particles. We will study a planar dc glow discharge, with the cath- ode made of molybdenum, using argon as discharge gas, and the substrate being located at the anode; the main geometri- cal parameters of the system are shown in Fig. 1. In glow discharge sputtering systems, we can distinguish two re- gions: the dark space of the cathode, where almost all the potential fall takes place, and a region that is approximately equipotential, called the plasma region. When ions from the plasma enter in the cathode dark space they are accelerated towards the cathode by the electric field; this flux of ions undergoes charge-exchange collisions with the thermal gas atoms, originating a flux of fast neutral atoms. Both fluxes of energetic particles, ions and neutrals, strike the cathode and produce the emission of sputtered particles and secondary electrons, these latter helping to sustain the discharge. More- over, a fraction of the incident gas atoms are reflected from the cathode and gives a flux of backscattered gas particles. The fluxes of the sputtered cathode atoms and the reflected gas atoms abandon the cathode and cross the plasma losing energy until they eventually arrive at the substrate. This article is organized as follows. In the next section, we will present a model for the glow discharge that connects all the above mentioned processes. Then, in Sec. III, we will analyze the dependence of the final results on the parameters that characterize the discharge. The main conclusions of this work will be summarized in Sec. IV.

Activated carbons obtained from coconut peel were oxidized using hydrogen peroxide. Superficial characteristics of these carbons were determined through N2and CO2isotherms and functional groups were characterized by TPD. Finally, the microcalorimetry technique was used in order to obtain the immersion enthalpies in diverse liquids and established the relation between them and the results obtained by the other characterization techniques. The results suggested that the immersion calorimetry allow establishing the difference between the supports and the catalysts.

Comprising specially commissioned essays, the Handbook provides a comprehensive overview of alternative theories of economic growth. It surveys major sub-fields (including classical, Kaleckian, evolutionary, and Kaldorian growth theories) and highlights cutting-edge issues such as the relationship between finance and growth, the interplay of trend and cycle, and the role of aggregate demand in the long run.

Zorflex® activated carbon fibers (ACF), reference FM100 198B, are used before and after an oxidizing procedure with H 3 PO 4 to study the adsorption of Pb 2+ . The point of zero charge was determined for the modified and unmodified fiber giving values of 2.3 and 4.3, respectively. After oxidizing the ACF, the fiber showed to have a greater Pb 2+ adsorption capacity in comparison with the unmodified fiber, which is related with the acid sites increase, where lead was mainly adsorbed. Determination of the BET area was carried out by nitrogen physisorption at 77K. ACFs presented superficial areas between 1000 and 1500 m 2 /g showing mostly, a microporous structure. The preliminary design of an adsorbent using the modified fiber is presented where the fiber superior physicochemical properties over the unmodified one are observed.

The construction of a heat-conduction flow microcalorimeter of the twin type, that uses thermopiles to detect thermal changes in the reference and reaction cells, is described. For comparative purposes, gold and silver cells, with different geometric shapes, are used. The calorimetric set is immersed in a water thermostat at a temperature of 25.000 ± 0.005°C. The thermostat is placed in a room whose temperature is controlled to 25.0 ± 0.2°C by an air thermostat. The calibration constant of the apparatus is determined for several values of electric work and power. Values of 22 WV1 and 14 WV1 are obtained for the gold and silver cells, respectively. The influence of the flow rate on the potential signal is studied. Chemical calibrations are performed with HCl-NaOH, THAM-HCl (trihidroxymethylaminomethane), and urea-water systems at different flow rates. The results are in good agreement with those reported in the literature.

El uso excesivo e ineficiente manejo del fertilizante nitrogenado en caña de azúcar (Saccharum officinarum L) causan contaminación de acuíferos. El objetivo de este estudio fue evaluar el rendimiento, rentabilidad y cantidad de nitrógeno lixiviado en caña de azúcar, bajo la aplicación fraccionada del nitrógeno total que se aplica a la caña de azúcar. El estudio se realizó en el Módulo de Riego I-1 La Antigua, Veracruz, México. Se evaluaron nueve tratamientos que resultaron de los factores: dosis 250, 200 y 150 kg ha-1 de N y fraccionamientos 2, 3 y 4. Las variables de respuesta fueron: rendimiento, relación Beneficio/Costo y lixiviación de N. Se encontró una actitud ligeramente positiva (3.3) en escala Likert hacia la reducción de la dosis y aumento en el fraccionamiento del N total que se aplica al cultivo. Para el rendimiento, solo el fraccionamiento mostró diferencias significativas; al fraccionar el nitrógeno en tres y cuatro aplicaciones se obtuvieron rendimientos superiores a 125 t ha-1. Las menores pérdidas por lixiviación se registraron con una dosis de 150 kg ha-1 de N fraccionada en tres y cuatro aplicaciones, esto es, 16.80 y 15.40 kg ha-1 de N respectivamente. Se concluyó que el empleo de dosis de 150 kg ha-1 y con tres fraccionamientos del N total aplicado, representa una alternativa más sustentable para la producción de caña de azúcar. Por lo tanto, este manejo puede resultar en una mayor absorción de N por el cultivo y menos N se lixiviará hacia el acuífero.

The purpose of this paper was to illustrate the procedure to obtain activated carbon from lignocellulosic residues through chemical and physical paths. A general surface characterization was made and aqueous solution isotherms were obtained in order to evaluate the behaviour of each carbon atom in solutions contaminated with selective ions. The other purpose was to show a simple way to perform a scale-up process of an absorber from the laboratory level to an industrial level, using the breaking curves in fixed beds developed through the continuous pursuit of the Pb(II) and Cr(VI) ions concentration in the effluent of the bed. Activated carbon was used to study the adsorption of Pb(II) and Cr(VI). Isotherms of aqueous adsorption were determined. This model was developed in order to examine its efficiency and to compare it with an experimental model made in the laboratory, which rendered very similar results. The main characteristic of the feasibility of the application of this design is the fact that neither tedious calculations nor mass transfer coefficients are required in order to construct the above-mentioned curves. The model was developed by applying concepts such as mass transfer zone (MTZ) and length of unused bed (LUB), which are the dynamical basis understanding for the adsorption process in fixed beds. As a complementary item of the experiment, within a pilot plant scale, a filter was developed in order to achieve flexibility when manipulating the most important adsorption parameters and to enable the control of the variables involved in the process that change the operating conditions.

This paper is an attempt to sketch a typology of a class of complex sentences, widely spread among different languages, in which the subordinate clauses cataphorically announced in the main clause. Sentences such as German Ich bleibe deshalb zu Hause, weil ich einen wichtigen Anruf erwarte, or Russian Ya zulas' ot togo, chto nie ponimala yego, can be cited as examples of such a construction. These sentences constitute, from our point of view, an intermediate stage between a discoursive construction that makes use of a typical device for discourse cohesion (i.e. phoric relationships) and a sentential construction. In the light of these considerations, it is proposed that there is a gradual transition between discourse and Syntax and not only from a diachronic point of view, but also from the perspective of a synchronic approach. The paper is based on facts from fifteen languages: Ancient Spanish, Ancient Greek, French, Latin, German, Finnish, Kimbundu, Hebrew, Catalan, Kipchak, Swedish, Russian, Polish, Hungarian and English.

International audience

The chapter primarily explores the likelihood of heat measurement by means of the calorimeter in the lithium-ion battery cells for different applications. The presented focus applications are electrical vehicle and smart grid application. The efficiency parameter for battery cell is established using state of the art isothermal calorimeter by taking the consideration of heat related measurement. The calorimeter is principally used for the determination of the heat flux of the battery cell. The main target is to achieve the precision and accuracy of measurement of battery cell thermal performance. In this chapter, the assessment of battery efficiency parameter is proposed. A newly devised efficiency calculation methodology is projected and illustrated. The procedure ensures the precision an accurate measurement of heat flux measurement and turns into more comparable efficiency parameter. In addition, the issue is to investigate thermal sensitivity to factors that influence the energy storage system performance, i.e., current rate and temperature requirements. The results provide insight into the establishment of new key performance indicator (KPI) efficiency specification of the battery system. The usage of the calorimetric experiments is presented to predict the temperature distribution over a battery cell and an array of cells.

International audience

International audience

International audience

We are grateful to InTech the publisher of the book "Thermodynamics - Interaction Studies - Solids, Liquids and Gases", for letting this publication being archived in this Open Access repository. The publication is available from Intech Open Access Publisher: http://www.intechopen.com/articles/show/title/thermodynamics-and-thermokinetics-to-model-phase-transitions-of-polymers-over-extended-temperature-a; International audience; A scientific understanding of the behaviour of polymers under extreme conditions of temperature and pressure becomes inevitably of the utmost importance when the objective is to produce materials with well-defined final in-use properties and to prevent the damage of materials during on-duty conditions. The proper properties as well as the observed damages are related to the phase transitions together with intimate pattern organization of the materials. Thermodynamic and thermokinetic issues directly result from the thermodynamic independent variables as temperature, pressure and volume that can stay constant or be scanned as a function of time. Concomitantly, these variables can be coupled with a mechanical stress, the diffusion of a solvent, and/or a chemically reactive environment. A mechanical stress can be illustrated in a chemically inert environment by an elongation and/or a shear. Diffusion is typically described by the sorption of a solvent. A chemical environment is illustrated by the presence of a reactive environment as carbon dioxide or hydrogen for example. Challenging aspects are polymer pattern multi scale organizations, from the nanometric to the macrometric scale, and their importance regarding industrial and technological problems, as described in the state of the art in Part 2. New horizons and opportunities are at hands through pertinent approaches, including advanced ad hoc experimental techniques with improved modelling and simulation. Four striking illustrations, from the interactions between a solvent and a polymer to the growth patterns, are illustrated in Part 3.

ISBN 978-2-952587-04-4; International audience

National audience

International audience