Algoritmo genético para solucionar el problema de dimensionamiento y programación de lotes con costos de alistamiento dependientes de la secuencia

The main purpose of this paper is to develop a hybrid genetic algorithmin order to determine the lot sizes and their production scheduling in asingle machine manufacturing system for multi-item orders, the objectivefunction minimizes the sum of holding costs, tardy costs and setup costs.The problem considers a set of orders to be processed each one with itsown due date. Each order must be delivered complete. In the schedulingare considered sequence dependent setup times. The proposed hybridgenetic algorithm has embedded a heuristic that is used to calculate itsfitness function. The heuristic method presents a modification on theoptimal timming algorithm in which are involved sequence dependentset up times. A design of experiments is developed in order to assess thealgorithm performance, which is also tested using random-generateddata and results are compared with those generated by an exact method.The results show that the algorithm achieves a good performance in bothsolution quality and time especially for large instances.El objetivo de este artículo es desarrollar un algoritmo genético el cualpermita determinar los tamaños de lote de producción y su programaciónen un sistema de manufactura de una máquina para órdenesmultiproducto, cuya función objetivo minimiza la suma de los costosde inventario por terminaciones tardías y de alistamiento. El problemacontempla un conjunto de órdenes a ser procesadas con sus respectivasfechas de entrega. Cada orden debe ser entregada en su totalidad. Dentrode la programación de los trabajos se consideran tiempos de alistamientodependientes de la secuencia. En la metaheurística implementada se utilizade manera embebida un método heurístico para el cálculo de la funciónde adaptación. El método heurístico presentado es una variación delOptimal Timming Algorithm el cual involucra los tiempos de alistamientodependientes de la secuencia. Se desarrolla un diseño de experimentospara probar el desempeño del algoritmo utilizando instancias generadasde forma aleatoria y comparando sus soluciones contra las encontradaspor un método exacto. Los resultados muestran que el algoritmo lograun buen desempeño tanto en tiempo de ejecución como en calidad de lasolución especialmente en instancias grandes.

Surface-Enhanced Raman spectroscopy of thiobenzoic acid on metal nanoparticles

Molecules adsorbed on some metal surfaces such as silver, copper and gold, can exhibit enormous Surface-enhanced Raman Scattering (SERS). The SERS effect has historically been associated with substrate roughness on two characteristic length scales [1,2]. Surface roughness on the 10 to 100 nm length scale supports the electromagnetic resonances which are the dominant mechanism of enhancement. A second mechanism often thought to require atomic scale roughness, is referred to as the chemical enhancement mechanism. This second mechanism involves the creation of new electronic excited states which result from adsorbate–substrate chemical interactions. These two mechanisms operate simultaneously making it difficult to isolate the role and magnitude of each one. In this work the SERS spectra of thiobenzoic acid (TBA) adsorbed on several silver colloids are recorded by using different excitation wavelengths. Taking advantage of the fact that SERS spectroscopy is both, surface selective and highly sensitive, we have attempted to determine the molecular structure of the surface complex once TBA is adsorbed on the metal. The analysis of the vibrational wavenumbers of the Raman and SERS spectra suggests that this molecule shows unidentate coordination to the silver surface through the sulphur atom. In order to confirm this conclusion DFT calculations have been carried out for different TBA-silver complexes concluding that the unidentate coordination is the most likely interaction of TBA on the metal surface. Wavelength-scanned SERS excitation spectroscopy involves the measurement of SERS signal by using several excitation wavelengths and it was recognized as a useful tool for checking the mechanisms responsible for the SERS enhancement [3]. We have studied the effect of the wavelength within the SERS spectra of TBA on silver colloid prepared by different methods and we have analyzed the intensity of the 8a vibrational mode of TBA recorded at about 1590 cm-1. The intensity of this mode is noticeably higher in the spectrum recorded with the 514.5 nm line (Fig. 1). This result is attributed to the presence of a resonant Raman effect associated to a photoinduced charge-transfer process when using the most energetic excitation line. Finally, it is important to mention the high affinity of TBA for the silver surfaces what allows for a detection limit estimated to be 0.01 microM.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Raman, SERS and DFT study of chemically-adsorbed thiobenzoic acid on silver nanoparticles

Thiocarboxylic acids are organosulphur compounds with general formula RC(O)SH. They are related to carboxylic acids by the replacement of one oxygen by sulphur. Two tautomers are possible, written as RC(S)OH and RC(O)SH. The second one is the majority species in solid state and solution of thiobenzoic acid (TBA) at room temperature [1], but derivatives from both tautomers are known so that the SERS spectrum can be originated by either one. Taking advantage of the fact that SERS spectroscopy is both surface selective and highly sensitive we have attempted to determine the molecular structure of TBA once it is adsorbed on the metal surface. To accomplish this SERS spectra of TBA have been recorded on different silver colloids. A combination of layer-by-layer method with spin-coating deposition of silver nanoparticles have been used to prepare SERS active substrates on which the homogeneity of the SERS signal of TBA has been analyzed. Fig. 1 (I) shows the Raman spectra of TBA in the neat liquid (a), 1 M aqueous solution at pH 14 (b), SERS spectrum of a 5x10-4 M silver colloid prepared by reduction of silver nitrate with sodium borohydride at pH 7 (c) and SERS spectrum of a 5x10-4 M silver colloid prepared by reduction of silver nitrate with hydroxylamine hydrochloride (d). The assignment of the Raman spectra has been based on the present work as well as on previous studies [2-4]. The two bands recorded at 1662 and 2572 cm-1 in Fig.1a, are assigned to (C=O) and (SH) modes, what confirms that the Raman spectrum in the neat liquid is due to the thiolic specie of TBA, RC(O)SH. In the Raman spectrum of the solution (Fig. 1b) a significant redshift of (C=O) mode of 52 cm-1 and the absence of the (SH) band are detected in agreement with the behavior observed in the SERS spectrum (Fig. 1c). The latter confirms that the thiol tautomer of thiobenzoate anion, RC(O)S-, is adsorbed on silver nanoparticles. Other important SERS enhancements have been registered for the following vibrational modes: 8a;ring, (C=O) and (CS) recorded at 1592, 1554 and 928 cm-1 in Fig. 1c and 1d, respectively. The last two modes, (C=O) and (CS), undergo wavenumber shifts of +40 and -40 cm-1 respectively, which are closely related with the coordination of thiobenzoate anion to the metal surface [5]. The analysis of the vibrational wavenumber of these modes suggests that this molecule shows unidentate coordination through the sulphur atom to the metal surface. In order to confirm this fact DFT calculations have been carried out for different silver complexes: I) bridging bidentate ligand, (II) chelating ligand and (III and IV) unidentate ligand (Fig. 2). Theoretical wavenumber of representative bands of these compounds have been compared to the experimental one concluding that the behavior of the unidentate ligand (III) is the most probably coordination type of TBA on the metal surface. In order to confirm these conclusions the SERS spectra of TBA on silver colloid prepared by reduction of silver nitrate with hydroxylamine hydrochloride at different concentration of analyte have been recorded as well (Fig. 1 (II)). It is well known that the SERS enhancement factor depends strongly on different factors and in particular on the adsorption properties of the probe and the analyte concentration on the surface coverage. In this sense TBA has shown a very good detection level for this particular silver colloid it being a highly SERS active molecule. The detection limit is estimated to be 0.01 molar. Finally, Fig. 3 shows a representative Raman mapping of TBA adsorbed on a silver substrate prepared by spin-coating. Generally speaking, the image represents a fairly homogeneous distribution of the SERS intensity highlighting some points where the intensity is stronger as is expected in areas with heterogeneous coverage. The reproducibility of this type of substrate is under study focusing their application as reproducible and ultrasensitive sensing assemblies by using TBA as the target molecule due its good SERS sensitivity.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Altos de Reveque: un asentamiento fortificado fenicio-púnico en el litoral de Andalucía oriental

We report preliminary results from research into a new fortified settlement located close to the western coast in the current province of Almería in the Southeast of the Iberian Peninsula. An analysis is made of the fortification system, consisting of a casemate walls, and of the archaeological materials collected at the surface, offering a chronology of the site between the second half of the 6th century B.C. to the end of the 5th or early 4th century B.C. The function proposed for the site is that of a strategic control of metal and agricultural resources by the ancient Phoenician city of Abdera.Se presentan los primeros datos sobre un nuevo asentamiento fortificado próximo al litoral occidental de la provincia de Almería, en el sureste de la Península Ibérica. Se analiza el sistema de muralla de casamatas, así como los materiales arqueológicos superficiales que permiten datar su funcionamiento entre la segunda mitad del siglo VI a. C. y finales del siglo V o principios del IV a. C. Se propone una funcionalidad relacionada con el control estratégico de recursos mineros y agrícolas por parte de la antigua ciudad fenicia de Abdera

Nanostructure ITO and get more of it. Better performance at lower cost

In this paper, we investigated how different growth conditions (i.e., temperature, growth time, and composition) allows for trading off cost (i.e., In content) and performance of nanostructured indium tin oxide (ITO) for biosensing applications. Next, we compared the behavior of these functionalized nanostructured surfaces obtained in different growth conditions between each other and with a standard thin film as a reference, observing improvements in effective detection area up to two orders of magnitude. This enhanced the biosensor's sensitivity, with higher detection level, better accuracy and higher reproducibility. Results show that below 150 °C, the growth of ITO over the substrate forms a homogenous layer without any kind of nanostructuration. In contrast, at temperatures higher than 150 °C, a two-phase temperature-dependent growth was observed. We concluded that (i) nanowire length grows exponentially with temperature (activation energy 356 meV) and leads to optimal conditions in terms of both electroactive surface area and sensitivity at around 300 °C, (ii) longer times of growth than 30 min lead to larger active areas and (iii) the In content in a nanostructured film can be reduced by 10%, obtaining performances equivalent to those found in commercial flat-film ITO electrodes. In summary, this work shows how to produce appropriate materials with optimized cost and performances for different applications in biosensing

Effect of Boriding on the Mechanical Properties of AISI 1045 Steel

Efecto en las propiedades mecánicas de un acero borurado 1045.Some mechanical properties of AISI 1045 borided steels were estimated in the present work. The boriding process was carried out by the powder pack method at 950°C with 8 h of treatment. The fatigue strength on borided notched specimens was evaluated with rotating bending tests (R=1) considering a stress concentration factor (Kt) of 2.53. Likewise, the presence of residual stresses in boride layers was established by the XRD technique. The Daimler-Benz Rockwell C test was used, also, to estimate the strength adhesion of the coated system. The results show a decrease in the fatigue strength of AISI borided steels due to the presence of high porosity in the layers. Finally, the Rockwell-C adhesion test showed no coating failure for the boride layer

Análisis cualitativo de temas construidos y emergentes a partir de una experiencia piloto de psicoterapia centrada en la compasión (PCC) en pacientes con cáncer avanzado

Introducción: Desde el Instituto Catalán de Oncología de Duran i Reinals, se desarrolla un modelo de Psicoterapia grupal Centrada en la Compasión” (PCC), enfocada a pacientes con cáncer en fase avanzada. El modelo trabaja constructos terapéuticos como “compasión” o “autocompasión”, junto a la atención consciente (mindfulness) para mejorar el bienestar emocional y ayudar al crecimiento personal y espiritual de estos pacientes. Objetivo: El presente estudio piloto tiene como objetivo evaluar la adecuación del nuevo modelo de PCC propuesto. Concretamente evalúa la adecuación de los constructos trabajados por la terapia, la existencia de nuevos temas relevantes para el paciente no contemplados en el modelo, y la consistencia global del modelo a nivel de estructura, tareas y contenido. Método: La metodología fue cualitativa, se grabó y transcribió un ciclo de 8 sesiones de PCC y se hizo un análisis temático del contenido de las sesiones. El análisis fue realizado por dos evaluadores de forma independiente. La muestra final estuvo formada por 9 pacientes. Resultado: Los resultados obtenidos indican que hay una buena adecuación de los constructos trabajados en la terapia y del modelo en general. Sin embargo, será necesario incluir el tema de las “relaciones interpersonales”, tema muy relevante para el paciente no contemplado en el modelo. Además, se obtuvo información sobre principales preocupaciones de los pacientes, dificultades a la hora de realizar algunas tareas propuestas y un feedback positivo de la propia psicoterapia y de su participación. Conclusiones: Este estudio piloto aporta información relevante que permite ajustar y mejorar la propuesta del modelo de PCC inicial

Photogrammetry as a New Scientific Tool in Archaeology: Worldwide Research Trends

Archaeology has made significant advances in the last 20 years. This can be seen by the remarkable increase in specialised literature on all archaeology-related disciplines. These advances have made it a science with links to many other sciences, both in the field of experimental sciences and in the use of techniques from other disciplines such as engineering. Within this last issue it is important to highlight the great advance that the use of photogrammetry has brought for archaeology. In this research, through a systematic study with bibliometric techniques, the main institutions and countries that are carrying them out and the main interests of the scientific community in archaeology related to photogrammetry have been identified. The main increase in this field has been observed since 2010, especially the contribution of UAVs that have reduced the cost of photogrammetric flights for reduced areas. The main lines of research in photogrammetry applied to archaeology are close-range photogrammetry, aerial photogrammetry (UAV), cultural heritage, excavation, cameras, GPS, laser scan, and virtual reconstruction including 3D printin

IAA : Información y actualidad astronómica (24)

Sumario : Máseres en el espacio.-- Venus Express.-- El complejo cinturón de asteroides.-- DECONSTRUCCIÓN Y otros ENSAYOS : Rotación diferencial y oscilaciones estelares.-- ACTUALIDAD.-- ENTRE BASTIDORES .-- HISTORIAS DE ASTRONOMÍA: El astrónomo de vista prodigiosa.-- CIENCIA: PILARES E INCERTIDUMBRES : Ondas gravitatorias.-- ACTIVIDADES IAA.Esta revista se publica con la ayuda FCT-08-0130 del Programa Nacional de Fomento de la Cultura Científica y Tecnológica 2008.N