64 research outputs found

    Surface nanostructuring of TiO2 thin films by ion beam irradiation

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    This work reports a procedure to modify the surface nanostructure of TiO2 anatase thin films through ion beam irradiation with energies in the keV range. Irradiation with N+ ions leads to the formation of a layer with voids at a depth similar to the ion-projected range. By setting the ion-projected range a few tens of nanometers below the surface of the film, well-ordered nanorods appear aligned with the angle of incidence of the ion beam. Slightly different results were obtained by using heavier (S+) and lighter (B+) ions under similar conditions

    Almeria’s Green Pest Management Revolution: An Opportunity That Arose from a Food Safety Alert

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    Almería, a province of Spain, is the leader in horticultural production on a Spanish and European scale. The specific conditions of greenhouse cultivation favor plant development, but also the proliferation of pests. This high incidence of pests was controlled in the past mainly by means of chemical phytosanitary treatments. The aim of the present work has been to analyze the tools facilitated by the Andalusian Government (Junta de Andalucía) to replace the usual pest management process, taking advantage of the context of the food safety alert arising from the detection of isophenphos-methyl in peppers from the province of Almeria in December 2007. The results illustrate that, unlike many programs of public subsidies which involve long-term expenditure, the aid in question took advantage of the socioeconomic situation following the food safety alert. The program led to substantial economic savings and met its objectives swiftly, achieving excellent results in terms of removing most of the pesticides used in the “conventional production system”. In the 2006–2007 season, only 515 hectares in Almería used biological control organisms, four years later, it reached 20,081 hectares, and the average area during the last ten years was 24,953 hectares. This shows that Almeria’s green pest management revolution had been consolidated

    Prototipagem rápida de um modelo complexo para fabricação de moldes de gesso para barbotina cerâmica

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    Computer assisted designing (CAD) is well known for several decades and employed for ceramic manufacturing almost since the beginning, but usually employed in the first part of the projectual ideation processes, neither in the prototyping nor in the manufacturing stages. The rapid prototyping machines, also known as 3D printers, have the capacity to produce in a few hours real pieces using plastic materials of high resistance, with great precision and similarity with respect to the original, based on unprecedented digital models produced by means of modeling with specific design software or from the digitalization of existing parts using the so-called 3D scanners. The main objective of the work is to develop the methodology used in the entire process of building a part in ceramics from the interrelationship between traditional techniques and new technologies for the manufacture of prototypes. And to take advantage of the benefits that allow us this new reproduction technology. The experience was based on the generation of a complex piece, in digital format, which served as the model. A regular 15 cm icosahedron presented features complex enough not to advise the production of the model by means of the traditional techniques of ceramics (manual or mechanical). From this digital model, a plaster mold was made in the traditional way in order to slip cast clay based slurries, freely dried in air and fired and glazed in the traditional way. This experience has shown the working hypothesis and opens up the possibility of new lines of work to academic and technological levels that will be explored in the near future. This technology provides a wide range of options to address the formal aspect of a part to be performed for the field of design, architecture, industrial design, the traditional pottery, ceramic art, etc., which allow you to amplify the formal possibilities, save time and therefore costs when drafting the necessary and appropriate matrixes to each requirement.Projeto assistido por computador (CAD) é bem conhecido por várias décadas e empregado na fabricação cerâmica desde o início, mas usualmente empregado na primeira parte dos processos na concepção do projeto, nem na prototipagem, nem nas fases de fabricação. As máquinas de prototipagem rápida, também conhecidas como impressoras 3D têm a capacidade de produzir, em poucas horas, peças utilizando materiais plásticos de alta resistência, com grande precisão e similaridade com relação ao original, com base em modelos digitais inéditos produzidos por meio de modelagem com softwares de projeto específico ou a partir da digitalização das peças existentes, utilizando os chamados scanners 3D. O principal objetivo deste trabalho é desenvolver a metodologia utilizada em todo o processo de construção de uma parte em cerâmica da inter-relação entre as técnicas tradicionais e novas tecnologias para a fabricação de protótipos. E para aproveitar os benefícios que nos permitem esta nova tecnologia de reprodução. A experiência baseou-se na geração de uma peça complexa, em formato digital, que serviu como modelo. Um icosaedro regular de 15 cm, complexo o suficiente para não sugerir a produção do modelo por meio das técnicas tradicionais cerâmicas (manual ou mecânica). A partir deste modelo digital, um molde de gesso feito na maneira tradicional para colagem por barbotina de massas à base de argila, secagem livre ao ar, queimada e esmaltada de maneira tradicional. Esta experiência mostrou a hipótese de trabalho e abre a possibilidade de novas linhas de trabalho a níveis acadêmicos e tecnológicos que serão explorados em um futuro próximo. Esta tecnologia oferece uma grande variedade de opções para lidar com o aspecto formal de uma peça a ser executada no campo do projeto, arquitetura, projeto industrial, a cerâmica tradicional, a arte cerâmica, etc., que permitem ampliar as possibilidades formais, economizar tempo e, portanto, os custos na elaboração das matrizes necessárias e adequadas para cada exigência.Centro de Tecnología de Recursos Minerales y Cerámic

    LiNi0.5Mn1.5O4 Thin Films Grown by Magnetron Sputtering under Inert Gas Flow Mixtures as High-Voltage Cathode Materials for Lithium-Ion Batteries

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    Delivering a commercial high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) cathode electrode for Li-ion batteries would result in a significant step forward in terms of energy density. However, the structural ordering of the spinel and particle size have considerable effects on the cathode material's cyclability and rate capability, which are crucial challenges to address. Here, a novel mid-frequency alternating current dual magnetron sputtering method was presented, using different Ar-N-2 gas mixtures ratios for the process gas to prepare various LNMO thin films with highly controlled morphology and particle size; as determined from X-ray diffraction, Raman spectroscopy and electron microscopy. It resulted in enhanced cycling and rate performance. This processing method delivered N-containing LNMO thin film electrodes with up to 15 % increased discharge capacity at 1 C (120 mAh g(-1)) with respect to standard LNMO (grown under only Ar gas flow) thin film electrodes, along with outstanding rate performance up to 10 C (99 mAh g(-1)) in the operating voltage window 3.5-4.85 V vs. Li+/Li. Besides, electrochemical impedance spectroscopy results showed that the intricate phase transitions present in standard LNMO electrodes were almost suppressed in N-containing LNMO thin films grown under different Ar-N-2 gas flow mixtures

    Canopy fruit location can affect olive oil quality in Arbequina hedgerow orchards

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    The effect of location of fruit in canopies of hedgerow olive trees (Olea europaea L., cv. ‘Arbequina’) on quality of virgin oil was tested by analyzing oils extracted from different height layers and faces of 9 olive hedgerows (6 North-South oriented and 3 East-West). Although sensory attributes were not different other oil quality parameters may be significantly modified by fruit position. In some hedgerows, oils extracted from fruits harvested from higher layers exhibited significantly higher stability against oxidation, along with higher palmitic acid, linoleic acid and phenol contents, but lower oleic acid content. Oils extracted from fruits harvested from East and North facing hedgerows oriented North-South and East-West, respectively, exhibited higher oleic contents and lower saturated and polyunsaturated fatty acid contents. The mean phenol content of oils extracted from fruits from a North-South oriented hedgerow was significantly greater from one of the East-West oriented hedgerows. These findings may be relevant for the design of future olive hedgerows destined for olive oil production

    Influence of canopy fruit location on morphological, histochemical and biochemical changes in two oil olive cultivars

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    The influence of different irradiance conditions was evaluated under natural solar radiation by comparing well-exposed (in) and shaded fruit (out) in canopies of olive trees (Olea europaea L). Over a 2-year period, from 50 days after full bloom up to harvest time, “in” and “out” olive samples of two genotypes (“Frantoio Millennio” and “Coratina 5/19”) were periodically collected. Morphological, histochemical, and biochemical analysis were performed to study the changes on fruit morphometric traits, oil body accumulation, and b-glucosidase enzyme activity. Some parameters were modified by shading inside the canopy in which the proportion of incident photosynthetically active radiation intercepted by the crop was 47%. Shaded fruits developed at slow rate and were characterized by late darkgoing time, reduced size, with a tendency toward oblong shape. The rapid histochemical procedure proposed to estimate the oil body accumulation during fruit ripening showed that a reduced irradiance caused a decrease in oil body density. The canopy position influenced, in a different way, the b-glucosidase activity in relation to the fruit-ripening stage in both genotypes. These findings indicate that providing an adequate and uniform lighting of the olive canopy by careful choices of orchard management practices can be a key factor for several yield components

    Condiciones y medio ambiente de trabajo en hospitales públicos provinciales de la ciudad de Córdoba, Argentina

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    Esta investigación se propuso caracterizar las condiciones de empleo, identificar riesgos laborales percibidos el trabajador y estimar la frecuencia de problemas de salud referidos por los integrantes de los equipos de salud de hospitales de la ciudad de Córdoba dependientes del Ministerio de Salud de la provincia de Córdoba. Se realizó un estudio de corte transversal sobre 453 trabajadores pertenecientes a hospitales públicos provinciales de la ciudad de Córdoba, seleccionados mediante muestreo probabilístico aleatorio simple, con un nivel de confianza del 95% y un error muestral del 5%, en quienes se aplicó un cuestionario autoadministrado durante el segundo semestre de 2012. Se halló que el 35% del personal está vinculado laboralmente mediante formas de contratación no permanentes. El pluriempleo alcanza al 36% de los encuestados. La percepción de riesgos biológicos alcanza el 77,9%, el 50,7% se expone a sustancias químicas y el 51,7% manipula cargas físicas de gran volumen. Los problemas de salud más frecuentemente señalados fueron: gastritis (28,3%), obesidad (24,3%), lumbalgia (19,6%), alteraciones del sueño (14,1%), tensión arterial elevada (12,4%). Las proporciones de trabajadores no estables y de pluriempleo, y la elevada percepción de riesgos en el ámbito laboral deberían motivar la formulación de políticas y normativas de mejora de las condiciones de trabajo y empleo

    Morphological evolution of pulsed laser deposited ZrO2 thin films

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    Morphological evolution of ZrO2 thin films deposited during pulsed laser deposition of Zr in O2 atmosphere has been experimentally studied at two different film deposition temperatures, 300 and 873 K. The roughness exponent, , the growth exponent, , the coarsening exponent, 1/z, and the exponent defining the evolution of the characteristic wavelength of the surface, p, for depositions at 300 K amounted to = 1.00.1, = 0.40.1, 1/z= 0.340.03, and p= 0.490.03, whereas for depositions carried out at 873 K amounted to = 0.30.3, = 0.40.2, and 1/z= 0.00.2. Experimental error becomes important due to the flat morphology of the films inherent to the deposition technique. The change in the surface topography with the film temperature has been studied with the help of a simple Monte Carlo model which indicates the existence of two different growth regimes: a shadowing dominated growth, occurring at low temperatures, characterized by calculated values = 1.000.04, = 0.500.04, p= 0.460.01, and 1/z= 0.350.02 and a diffusion dominated growth that takes place at high temperatures as well as at low deposition rates, characterized by calculated values = 0.150.08, = 0.330.04, and 1/z= 0.330.07. The good agreement obtained between the experimental and simulated parameters is discussed within the frame of the general characteristics of the deposition method.Universidad Nacional Autónoma de México-PAPIIT-IN107808Consejo Nacional de Ciencia y Tecnología de México-CONACyT-50203-FMinisterio de Ciencia, Innovación y Universidades de España-MAT 2007-65764, PIE 200960I132 y CONSOLIDER INGENIO 2010-CSD2008-00023Junta de Andalucía-TEP2275 y P07-FQM-0329

    Supersonic Kinks in Coulomb lattices

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    There exist in nature examples of lattices of elements for which the interaction is repulsive, the elements are kept in place because different reasons, as border conditions, geometry (e.g., circular) and, certainly, the interaction with other elements in the system, which provides an external potential. A primer example are layered silicates as mica muscovite, where the potassium ions form a two dimensional lattice between silicate layers. We propose an extremely simplified model of this layer in order to isolate the properties of a repulsive lattice and study them. We find that they are extremely well suited for the propagation of supersonic kinks and multikinks. Theoretically, they may have as much energy and travel as fast as desired. This striking results suggest that the properties of repulsive lattices may be related with some yet not fully explained direct and indirect observations of lattice excitations in muscovite
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