205 research outputs found

    Routing design for less-than-truckload motor carriers using ant colony techniques

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    One of the most important challenges for Less-Than-Truck-Load carriers consists of determining how to consolidate flows of small shipments to minimize costs while maintaining a certain level of service. For any origin-destination pair, there are several strategies to consolidate flows, but the most usual ones are: peddling/collecting routes and shipping through one or more break-bulk terminals. Therefore, the target is determining a route for each origin-destination pair that minimizes the total transportation and handling cost guaranteeing a certain level of service. Exact resolution is not viable for real size problems due to the excessive computational time required. This research studies different aspects of the problem and provides a metaheuristic algorithm (based on Ant Colonies Optimization techniques) capable of solving real problems in a reasonable computational time. The viability of the approach has been proved by means of the application of the algorithm to a real Spanish case, obtaining encouraging results

    ROUTING DESIGN FOR LESS-THAN-TRUCKLOAD MOTOR CARRIERS USING ANT COLONY TECHNIQUES

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    One of the most important challenges for Less-Than-Truck-Load carriers consists of determining how to consolidate flows of small shipments to minimize costs while maintaining a certain level of service. For any origin-destination pair, there are several strategies to consolidate flows, but the most usual ones are: peddling/collecting routes and shipping through one or more break-bulk terminals. Therefore, the target is determining a route for each origin-destination pair that minimizes the total transportation and handling cost guaranteeing a certain level of service. Exact resolution is not viable for real size problems due to the excessive computational time required. This research studies different aspects of the problem and provides a metaheuristic algorithm (based on Ant Colonies Optimization techniques) capable of solving real problems in a reasonable computational time. The viability of the approach has been proved by means of the application of the algorithm to a real Spanish case, obtaining encouraging results.

    Radio continuum properties of luminous infrared galaxies. Identifying the presence of an AGN in the radio

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    Luminous infrared galaxies are systems enshrouded in dust, which absorbs most of their optical/UV emission and re-radiates it in the mid- and far-infrared. Radio observations are largely unaffected by dust obscuration, enabling us to study the central regions of LIRGs in an unbiased manner. The main goal of this project is to examine how the radio properties of local LIRGs relate to their infrared spectral characteristics. Here we present an analysis of the radio continuum properties of a subset of the Great Observatories All-sky LIRG Survey (GOALS), which consists of 202 nearby systems (z<0.088). Our radio sample consists of 35 systems, or 46 individual galaxies, that were observed at both 1.49 and 8.44 GHz with the VLA with a resolution of about 1 arcsec (FWHM). The aim of the project is to use the radio imagery to probe the central kpc of these LIRGs in search of active galactic nuclei. We used the archival data at 1.49 and 8.44 GHz to create radio-spectral-index maps using the standard relation between flux density Sv and frequency v, S~v^-a, where a is the radio spectral index. By studying the spatial variations in a, we classified the objects as radio-AGN, radio-SB, and AGN/SB (a mixture). We identified the presence of an active nucleus using the radio morphology, deviations from the radio/infrared correlation, and spatially resolved spectral index maps, and then correlated this to the usual mid-infrared ([NeV]/[NeII] and [OIV]/[NeII] line ratios and EQW of the 6.2 um PAH feature) and optical (BPT diagram) AGN diagnostics. We find that 21 out of the 46 objects in our sample are radio-AGN, 9 are classified as starbursts (SB), and 16 are AGN/SB. After comparing to other AGN diagnostics we find 3 objects out of the 46 that are identified as AGN based on the radio analysis, but are not classified as such based on the mid-infrared and optical AGN diagnostics presented in this study.Comment: 33 pages, 7 figures, 5 tables, to appear in A&

    Modeling Ovoproduct Spoilage with Red Led Light

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    Heat-treatment of ovoproducts is often required to ensure microbial safety. However, it has been shown that in most microbial species slow heating, or heat shocks may induce a higher heat resistance, that means that it is not possible to remove the microbial flora completely. These microorganisms produce on ovoproducts spoilage especially when the cold chain is broken along the transportation and/or storage. As a result, the life span for the product is shortened. The microbial activity inside the product causes changes in several physical properties, which can be supervised using optical methods. The aim of this work is to monitor the sigmoid behaviour underlying the ovoproduct evolution and spoilage by means of red LED light. For two commercial types of liquid and pasteurized egg white, storage at 9°C, an average correlation of r=0.94 has been found between microorganism growth and mean grey level of LED light passing though the sample. The results show that it is possible to develop very simple predictive models taking into account only one optical parameter corre¬sponding to a single LED

    Supervision of ovoproducts spoilage with red led light

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    Heat-treatment of ovoproducts is often required to ensure microbial safety. However, it has been shown that in most microbial species slow heating, or heat shocks may induce a higher heat resistance, that means that it is not possible to remove the microbial flora completely. These microorganisms produce on ovoproducts spoilage especially when the cold chain is broken along the transportation and/or storage. As a result, the life span for the product is shortened. The microbial activity inside the product causes changes in several physical properties, which can be supervised using optical methods. The aim of this work is to monitor the sigmoid behaviour underlying the ovoproduct evolution and spoilage by means of red LED light. For two commercial types of liquid and pasteurized egg white, storage at 9ºC, an average correlation of r=0.94 has been found between microorganism growth and images mean grey level of LED light passing though the sample. The results show that it is possible to develop very simple predictive models taking into account only one optical parameter corresponding to a single LED

    Supervisión de la degradación de ovoproducto mediante diodos emisores de luz

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    La extrema sensibilidad de los ovoproductos al deterioro microbiano hace necesaria la aplicación de un tratamiento térmico que asegure su inocuidad. El hecho de que el tratamiento térmico no asegure la completa erradicación de la flora microbiana junto con la falta de mantenimiento de la cadena de frío a lo largo de la distribución y/o conservación del mismo limita y acorta la vida útil del producto. La degradación microbiana del ovoproducto afecta a ciertas propiedades físicas del mismo cuya alteración puede ser objeto de supervisión mediante técnicas ópticas siendo el objetivo de este trabajo la realización de un estudio preliminar para la supervisión de la degradación de ovoproducto mediante LED con el objeto de hacer una propuesta de implantación en laboratorios de calidad en la industria. Los resultados muestran que en clara líquida pasteurizada el aumento del contenido microbiano a lo largo del tiempo de almacenamiento se correlaciona (con valores de hasta r = 0.97) con el incremento en el nivel de intensidad lumínica detectado en las muestras. En la yema a partir de niveles altos de concentración de microorganismos los fenómenos de turbidez y gelificación se identifican con una disminución en los valores de los parámetros ópticos considerados

    Ovoproductos

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    La extrema sensibilidad de los ovoproductos al deterioro microbiano hace necesaria la aplicacion de un tratamiento termico que asegure su inocuidad. El hecho de que el tratamiento termico no asegure la completa erradicacion de la flora microbiana junto con la falta de mantenimiento de la cadena de fn'o a lo largo de la distribucion y/o conservacion del mismo limita y acorta la vida util del producto. La degradacion microbiana del ovoproducto afecta a ciertas propiedades ffsicas del mismo cuya alteration puede ser objeto de supervision mediante tecnicas opticas siendo el objetivo de este trabajo la realization de un estudio preliminar para la supervision de la degradacion de ovoproducto mediante LED con el objeto de hacer una propuesta de implantation en laboratories de calidad en la industria. Los resultados muestran que en clara liquida pasteurizada el aumento del contenido microbiano a lo largo del tiempo de almacenamiento se correlaciona (con valores de hasta r = 0.97) con el incremento en el nivel de intensidad luminica detectado en las muestras, siendo posible establecer modelos sencillos de prediction de la carga microbiana a traves de este para metro optico y empleando la information correspondiente a un unico LED. - Heat-treatment of ovoproducts is often required to ensure microbial safety. However, it has been shown that in most microbial species slow heating, or heat shocks may induce a higher heat resistance, that means that it is not possible to remove the microbial flora completely. These microorganisms produce ovoproducts spoilage especially when the cold chain is broken along the transport and/or storage. As result, the useful life for the product is shorten. The microbial activity in the product changes several physical properties which can be supervised using optical methods, so the goal of this work is to carry out a prospective study for the supervision of ovoproduct spoilage with scatter red LED light. For liquid and pasteurizated white egg it has been found a correlation (r=0.97) between microorganism growth and grey level of LED light passing thought out the sample

    Diseño y optimización de sistemas de transformación y conservación de naranja variedad “Canoneta” de la Serra Nord mallorquina para obtención de naranja IV gama

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    Este trabajo muestra el efecto de diferentes tipos de procesado sobre la vida útil de naranjas mínimamente procesadas de la variedad “Canoneta”. Las naranjas peladas de manera mecánica o semimanual fueron envasadas en dos atmósferas (vacío parcial y 20% CO2+ 80% N2) y se almacenaron durante 10 días a 4ºC y a 8ºC. Los análisis sensoriales, microbiológicos y físicoquímicos identificaron el pelado semi-manual como el menos idóneo de los métodos de pelado y se estableció 7 días como la vida útil máxima para un producto aceptable desde el punto de vista sensorial

    C-GOALS II. Chandra Observations of the Lower Luminosity Sample of Nearby Luminous Infrared Galaxies in GOALS

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    We analyze Chandra X-ray observatory data for a sample of 63 luminous infrared galaxies (LIRGs), sampling the lower-infrared luminosity range of the Great Observatories All-Sky LIRG survey (GOALS), which includes the most luminous infrared selected galaxies in the local universe. X-rays are detected for 84 individual galaxies within the 63 systems, for which arcsecond resolution X-ray images, fluxes, infrared and X-ray luminosities, spectra and radial profiles are presented. Using X-ray and MIR selection criteria, we find AGN in (31±\pm5)% of the galaxy sample, compared to the (38±\pm6)% previously found for GOALS galaxies with higher infrared luminosities (C-GOALS I). Using mid-infrared data, we find that (59±\pm9)% of the X-ray selected AGN in the full C-GOALS sample do not contribute significantly to the bolometric luminosity of the host galaxy. Dual AGN are detected in two systems, implying a dual AGN fraction in systems that contain at least one AGN of (29±\pm14)%, compared to the (11±\pm10)% found for the C-GOALS I sample. Through analysis of radial profiles, we derive that most sources, and almost all AGN, in the sample are compact, with half of the soft X-ray emission generated within the inner 1\sim 1 kpc. For most galaxies, the soft X-ray sizes of the sources are comparable to those of the MIR emission. We also find that the hard X-ray faintness previously reported for the bright C-GOALS I sources is also observed in the brightest LIRGs within the sample, with LFIR>8×1010L_{\rm FIR}>8\times10^{10} L_{\odot}.Comment: 24 pages, 13 figures, 11 tables, accepted for publication in A&
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