938 resultados para cBN grinding wheel
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El presente proyecto de grado se inscribe bajo el proyecto de Responsabilidad Social Empresarial de la línea de investigación de Realidad Empresarial de la Facultad de Administración de la Universidad del Rosario. El problema de investigación surge de dos problemas actuales, que convergen en la insostenibilidad a largo y mediano plazo de la manera en que se hacen la mayoría de los negocios hoy en día. El primer problema, es el de suficiencia, se evidencia desde el punto de vista del consumidor, el cual pareciera estar diseñado para comprar y acumular objetos y cosas que luego de un tiempo irán a parar a la basura. El segundo problema es el modelo de negocio que extrae recursos, los transforma, los comercializa de manera repetitiva y obliga al cliente a seguir comprando, olvidando que la mayoría de cosas que produce, terminan en el basurero. La deficiencia actual del consumismo insostenible y del diseño que no piensa en las generaciones futuras son dos caras de la misma moneda. Por eso es que se estudia el problema desde la perspectiva tanto del consumidor, como del productor. Las tendencias internacionales relacionadas con la sostenibilidad están llevando a los negocios por una nueva senda, la cual les dará ventajas competitivas a los adoptadores tempranos. A raíz de los problemas planteados y con el objetivo de encontrar la sostenibilidad empresarial, se estudia una posible solución para cada actor del problema. Por el lado del consumidor, se analiza la teoría que gira alrededor del consumo responsable y de cómo los consumidores tienen el poder de causar un efecto positivo con lo que mejor saben hacer: comprando (y eligiendo que comprar). Por el lado del productor se estudia un nuevo modelo de negocios llamado el sistema producto-servicio, el cual se enfoca a satisfacer necesidades de los clientes por medio de una combinación de prestación de servicios y facilitación de productos, en vez de la comercialización de estos. Es decir que en vez de vender cosas que los consumidores quieran acumular (problema de suficiencia), se les vende soluciones que satisfagan sus necesidades, reteniendo la compañía la propiedad sobre los productos que integran al servicio. Se estudia también de que maneras este modelo particular de sistemas producto-servicio puede ser recibido por los consumidores de hoy en día, tan acostumbrados al modelo actual. Se quiere explorar el sistema de productos y servicio como una alternativa empresarial perdurable que solucione los retos ambientales del siglo XXI. Para poder probar la viabilidad de este hipotético modelo que cambia los patrones de interacción de las empresas con los usuarios, se plantea una idea de negocio que integre productos y servicios para satisfacer las necesidades del cliente. Se escogió un área viii caracterizada por ser de las más consumistas y acumuladoras en cuanto al volumen de compras anual de los clientes: el negocio de la ropa. Y no solo cualquier tipo de ropa, sino el de la moda rápida, un modelo que obliga a los consumidores a comprar ropa con una frecuencia aún mayor. Se hizo esto con el objetivo de probar que el modelo propuesto puede funcionar inclusive bajo los supuestos más “consumistas” que existen hoy en día.
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Detectar las características diferenciales de los escolares que mejor se beneficien de los programas instruccionales emotivos dirigidos a la mejora del ajuste personal y la adaptación escolar y social, así como aquellas otras características que pudieran provocar un efecto de estancamiento o, incluso empeoramiento. Investigación I: cuestionario a expertos, n: 40 psicólogos. Investigación II: muestra 1: 84 escolares de cuarto de EGB; muestra 2: 285 escolares de sexto de EGB; muestra 3: 143 escolares de octavo de EGB. Total: 512 escolares de EGB. Invest.I: respuestas experienciales dadas por psicólogos sobre aspectos favorecedores de buen pronóstico. Invest.II: Estudio 1: diseño intra e intergrupo con medidas repetidas pre y post tratamiento. Variable independiente, tratamiento. Variable dependiente, cambio en adaptación personal, escolar y social. Estudio 2: interrelación factorial del pretest, en contraste con la interrelación de los cambios operados después del tratamiento. Estudio 3: variables predictoras: edad, sexo, aptitudes técnicas y hábitos de estudio, rendimiento académico, adaptación y estilos educativos de los padres; variable criterio: cambio en la adaptación personal, escolar y social. Invest.I: Cuestionario a expertos sobre variables predictoras de un buen pronóstico. Invest.II: Test de inteligencia Lorge-Thorndike, no verbal; Banneb, EHE, PESA y ESDA, Hernández, 1983; Tamai, Hernández, 1983; EOTE y DEOTE, Hernández y García, 1985; FIS, CBS y CBN, Sección Departamental Psicología Educativa, Universidad de la Laguna. Invest. I: cómputo de respuestas y detección de coincidencias. Invest.II: Estudio 1: cuarto de EGB, ANOVA inter o intragrupo; sexto y octavo de EGB, análisis de las diferencias de medias antes-despues, T-test. Estudio 2: Correlación de Pearson. Estudio 3: Análisis de varianza; Oneway y análisis de la función discriminante; método RAO. 1. Los alumnos que más se benefician son los que expresaban mayores sentimientos de miedo, tristeza y autoculpa. Mostraban actitudes de choque con las normas y tendencia a aislarse. Sin embargo, no se detectaban dificultades en el estudio, gozando de mejores capacidades intelectivas, de menor edad y de unos padres menos restrictivos. 2. En los alumnos que empeoran se detecta un contraste entre su autoevaluación (expresan menos dificultades adaptativas) y otros criterios más externos (tendencia a sobrevalorarse, personas autosuficientes y conflictivas según sus compañeros, peor rendimiento intelectual y académico). 3. Los alumnos que se mantienen, parten de menores dificultades adaptativas y de estudio. La presente investigación nos permite realizar pronósticos diferenciales sobre qué personas pueden beneficiarse con este tipo de programas y para quienes, en cambio, no es eficaz. Nos proporciona información sobre las variables específicas sobre las que se debe incidir para optimizar los resultados.
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The purpose of this article is to analyze the coverage made by CNN and Al Jazeera (in Arabic) to operation Caste Lead and the Goldstone Report during 2008 and 2009. This investigation is based in the theory of Qualitative Analysis of Content, by Wildemuth and Zhang. The methodology follows up with the one proposed by the authors in the main theory, complementing it with the Gamson and Modigliani´s Framing theory. The methodology mention above display the different in the coverage development, determined by the geopolitical influences; being CNN more influenced by a Western pro USA and pro Israeli speech, while Al Jazeera is more prone to support the Palestinian cause, this is the thesis of this article. During the development of the investigation, the thesis was demonstrated to be only partially accurate as CNN was not completely supportive to the Israeli arguments during the coverage, but Al Jazeera did have preferential speech for the Palestinian cause.
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Resumen tomado del autor. Resumen en castellano e inglés. Notas a pie de página. Este artículo se incluye en el monográfico 'Didácticas específicas'
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Les lesions cerebrals per traumatismes craniencefàlics són la causa més freqüent de defunció en els accidents de trànsit en els que estan implicats vehicles de dues rodes. Malgrat la provada eficàcia de l'ús del casc per amortir les lesions en cas d'accidents, molts adolescents i joves no el fan servir o fan un ús incorrecte. El principal objectiu d'aquesta investigació és identificar les variables que millor prediuen l'ús del casc entre els adolescents. En la recerca es combinen la metodologia quantitativa i qualitativa i consta de dues fases. A la primera fase participen 876 estudiants de secundària (46,8% nois) amb edats compreses entre 14 i 18 anys. A la segona fase, s'estudien quatre casos d'adolescents que han patit un accident greu circulant amb ciclomotor i que no portaven el casc o feien un ús incorrecte. Els resultats suggereixen que l'edat i la influència social són les variables més rellevants per predir l'ús continuat del casc entre els adolescents. De l'estudi se'n deriven estratègies d'intervenció per incrementar l'ús del casc entre els dolescents.
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India's Constitution is not a covenant, or compact, between the states. The states are the creation of Constitution and subsequently of Parliament. Article 2 of the Constitution empo-wers Parliament to admit into Union, or establish new States on such terms and conditions as it thinks fit . Article 3 gives more comprehensive powers to Parliament for formation of new states and alteration of areas, boundaries or names of the existing States.The Indian Constitution not only permits, but also ordains various States to enact special laws to limit the ownership of land only to some designated residents. Goa does not have to reinvent the wheel. As a full-fledged State of the Indian Union it has to only convince the Union government that the ground of its legitimacy as a State is doomed without the Special Status which may empower the State Government to adopt legal instruments to safeguard its cultural and territorial identity and integrity, the ground of its Statehood.
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A driver controls a car by turning the steering wheel or by pressing on the accelerator or the brake. These actions are modelled by Gaussian processes, leading to a stochastic model for the motion of the car. The stochastic model is the basis of a new filter for tracking and predicting the motion of the car, using measurements obtained by fitting a rigid 3D model to a monocular sequence of video images. Experiments show that the filter easily outperforms traditional filters.
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The aim of this study was to examine the mechanisms by which gypsum increases the sorption of fertilizer-P in soils of and and semi-arid regions. Either gypsum or soil (Usher from the UK; pH 7.8, 7% organic matter, 21% CaCO3: Yasouj from Iran; pH 8.2, 1.4% OM, 18% CaCO3: Ghanimeh from Saudi Arabia; pH 7.8, 1% OM, 26% CaCO3, 13% gypsum) was shaken for 24 It with KH2PO4 solutions in 10 mM CaCl2. With gypsum, grinding increased sorption by a factor of about 3, and increase in pH from 5.6 to 7.5 greatly increased sorption. Scanning electron micrographs (SEM) and EDX quantitative analysis showed that small crystals of gypsum disappeared and roughly spherical particles of dicalcium phosphate (DCPD) were formed. Analysis of equilibrium Solutions showed, using GEOCHEM, that octa-calcium phosphate (OCP) coated the DCPD. For the soils, sorption was in the order Ghanimeh > Yasouj > Usher. Removal of gypsum from Ghanimeh reduced sorption, with precipitated gypsum having a greater effect than gypsum mixed physically with the soil. Addition to Usher had no effect. SEM and EDX could not be used in the soil matrix, but solubility analysis again showed that solutions were close to equilibrium with OCP. Usher was unresponsive to added gypsum, presumably because of its small sorption capacity and high organic matter content. In Ghanimeh and Yasouj soils, gypsum increased sorption by being a source of readily available Ca2+ (c) 2005 Elsevier B.V. All rights reserved.
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Sediment and P inputs to freshwaters from agriculture are a major problem in the United Kingdom (UK). This study investigated mitigation options for diffuse pollution losses from arable land. Field trials were undertaken at the hillslope scale over three winters at three UK sites with silt (Oxyaquic Hapludalf), sand (Udic Haplustept), and clay (Typic Haplaquept) soils. None of the mitigation treatments was effective in every year trialled, but each showed overall average reductions in losses. Over five site years, breaking up the compaction in tramlines (tractor wheel tracks) using a tine reduced losses of sediment and P to losses similar to those observed from areas without tramlines, with an average reduction in P loss of 1.06 kg TP ha(-1) Compared to traditional plowing, TP losses under minimum tillage were reduced by 0.30 kg TT ha(-1) over five site years, TP losses under contour cultivation were reduced by 0.30 kg TP ha(-1) over two site years, and TP losses using in-field barriers were reduced by 0.24 kg TP ha(-1) over two site years. In one site year, reductions in losses due to crop residue incorporation were nor significant. Each of the mitigation options trialled. is associated with a small cost at the farm-scale of up to 5 pound ha(-1), or with cost savings. The results indicate that each of the treatments his the potential to be a cost-effective mitigation option, but that tramline management is the most promising treatment, because tramlines dominate sediment and P transfer in surface runoff from arable hillslopes.
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This study investigated the potential of Dichrostachys cinerea fruits as a protein supplement in semi-arid areas of Zimbabwe. The tanniniferous fruits were treated with aqueous solutions of polyethylene glycol (PEG) or sodium hydroxide (NaOH). Both treatments increased the soluble fraction, rate of degradation and effective degradability (ED) of nitrogen (N) in sacco. The PEG effects were higher than the NaOH effects (e.g. a 25% vs. 6% increase in effective N degradabilities, respectively). Five treatments were evaluated in a N-balance trial using Matebele goats: ground, PEG- or NaOH-treated D. cinerea fruits, a commercial protein supplement (CPS) and no supplement. Animals offered ground fruits or CPS retained most N (3.7 or 4.1 g N/day, respectively), while those offered NaOH- or PEG-treated fruits retained significantly less N (2.7 or 1.0 g/day, respectively). Unsupplemented animals were in negative N balance (-2.4 g/day). PEG treatment deactivated the tannins more than the NaOH treatment. PEG treatment resulted in excessive protein degradation in the rumen leading to high urine N loss. It is concluded that the D. cinerea fruits were beneficial for goat N-nutrition and that the tannins did not require inactivation. D. cinerea fruits can, therefore, replace the expensive commercial protein supplement. It is also suggested that the collection and grinding of fruits could be used as a management tool to control bush encroachment. (C) 2004 Elsevier B.V. All rights reserved.
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Tungsten carbide/oxide particles have been prepared by the gel precipitation of tungstic acid in the presence of an organic gelling agent [10% ammonium poly(acrylic acid) in water, supplied by Ciba Specialty Chemicals]. The feed solution; a homogeneous mixture of sodium tungstate and ammonium poly(acrylic acid) in water, was dropped from a 1-mm jet into hydrochloric acid saturated hexanol/concentrated hydrochloric acid to give particles of a mixture of tungstic acid and poly(acrylic acid), which, after drying in air at 100 degrees C and heating to 900 degrees C in argon for 2 h, followed by heating in carbon dioxide for a further 2 h and cooling, gives a mixture of WO, WC, and a trace of NaxWO3, with the carbon for the formation of WC being provided by the thermal carbonization of poly(acrylic acid). The pyrolyzed product is friable and easily broken down in a pestle and mortar to a fine powder or by ultrasonics, in water, to form a stable colloid. The temperature of carbide formation by this process is significantly lower (900 degrees C) than that reported for the commercial preparation of tungsten carbide, typically > 1400 degrees C. In addition, the need for prolonged grinding of the constituents is obviated because the reacting moieties are already in intimate contact on a molecular basis. X-ray diffraction, particle sizing, transmission electron microscopy, surface area, and pore size distribution studies have been carried out, and possible uses are suggested. A flow diagram for the process is described.
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Why it is easier to cut with even the sharpest knife when 'pressing down and sliding' than when merely 'pressing down alone' is explained. A variety of cases of cutting where the blade and workpiece have different relative motions is analysed and it is shown that the greater the 'slice/push ratio' xi given by ( blade speed parallel to the cutting edge/blade speed perpendicular to the cutting edge), the lower the cutting forces. However, friction limits the reductions attainable at the highest.. The analysis is applied to the geometry of a wheel cutting device (delicatessan slicer) and experiments with a cheddar cheese and a salami using such an instrumented device confirm the general predictions. (C) 2004 Kluwer Academic Publishers.
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Reactions in (molecular) organic crystalline solids have been shown to be important for exerting control that is unattainable over chemical transformations in solution. Such control has also been achieved for reactions within metal– organic cages. In these examples, the reactants are already in place within the crystals following the original crystal growth. The post-synthetic modification of metal–organic frameworks (MOFs and indeed reactions and catalysis within MOFs have been recently demonstrated; in these cases the reactants enter the crystals through permanent channels. Another growing area of interest within molecular solid-state chemistry is synthesis by mechanical co-grinding of solid reactants—often referred to as mechanochemistry. Finally, in a small number of reported examples, molecules also have been shown to enter nonporous crystals directly from the gas or vapor phase, but in only a few of these examples does a change in covalent bonding result, which indicates that a reaction occurs within the nonporous crystals. It is this latter type of highly uncommon reaction that is the focus of the present study.
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Rationale: Increased food consumption following Δ9- tetrahydrocannabinol-induced cannabinoid type 1 receptor agonism is well documented. However, possible non-Δ9- tetrahydrocannabinol phytocannabinoid-induced feeding effects have yet to be fully investigated. Therefore, we have assessed the effects of the individual phytocannabinoids, cannabigerol, cannabidiol and cannabinol, upon feeding behaviors. Methods: Adult male rats were treated (p.o.) with cannabigerol, cannabidiol, cannabinol or cannabinol plus the CB1R antagonist, SR141716A. Prior to treatment, rats were satiated and food intake recorded following drug administration. Data were analyzed for hourly intake and meal microstructure. Results: Cannabinol induced a CB1R-mediated increase in appetitive behaviors via significant reductions in the latency to feed and increases in consummatory behaviors via increases in meal 1 size and duration. Cannabinol also significantly increased the intake during hour 1 and total chow consumed during the test. Conversely, cannabidiol significantly reduced total chow consumption over the test period. Cannabigerol administration induced no changes to feeding behavior. Conclusion: This is the first time cannabinol has been shown to increase feeding. Therefore, cannabinol could, in the future, provide an alternative to the currently used and psychotropic Δ9-tetrahydrocannabinol-based medicines since cannabinol is currently considered to be non-psychotropic. Furthermore, cannabidiol reduced food intake in line with some existing reports, supporting the need for further mechanistic and behavioral work examining possible anti-obesity effects of cannabidiol.
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Chitosan and its half-acetylated derivative have been compared as excipients in mucoadhesive tablets containing ibuprofen. Initially the powder formulations containing the polymers and the drug were prepared by either co-spray drying or physical co-grinding. Polymer–drug interactions and the degree of drug crystallinity in these formulations were assessed by infrared spectroscopy and differential scanning calorimetry. Tablets were prepared and their swelling and dissolution properties were studied in media of various pHs. Mucoadhesive properties of ibuprofen-loaded and drug-free tablets were evaluated by analysing their detachment from pig gastric mucosa over a range of pHs. Greater polymer–drug interactions were seen for spray-dried particles compared to co-ground samples and drug loading into chitosan-based microparticles (41%) was greater than the corresponding half-acetylated samples (32%). Swelling and drug release was greater with the half-acetylated chitosan tablets than tablets containing the parent polymer and both tablets were mucoadhesive, the extent of which was dependent on substrate pH. The results illustrate the potential sustained drug delivery benefits of both chitosan and its half-acetylated derivative as mucoadhesive tablet excipients.