300 research outputs found

    Evaluation of frozen ground conditions along a coastal topographic gradient at Byers Peninsula (Livingston Island, Antarctica) by geophysical and geoecological methods

    Get PDF
    Geophysical surveying and geoelectricalmethods are effective to study permafrost distribution and conditions in polar environments. Geoelectrical methods are particularly suited to study the spatial distribution of permafrost because of its high electrical resistivity in comparison with that of soil or rock above 0 °C. In the South Shetland Islands permafrost is considered to be discontinuous up to elevations of 20–40ma.s.l., changing to continuous at higher altitudes. There are no specific data about the distribution of permafrost in Byers Peninsula, in Livingston Island, which is the largest ice-free area in the South Shetland Islands. With the purpose of better understanding the occurrence of permanent frozen conditions in this area, a geophysical survey using an electrical resistivity tomography (ERT)methodologywas conducted during the January 2015 field season, combined with geomorphological and ecological studies. Three overlapping electrical resistivity tomographies of 78meach were done along the same profile which ran from the coast to the highest raised beaches. The three electrical resistivity tomographies are combined in an electrical resistivitymodel which represents the distribution of the electrical resistivity of the ground to depths of about 13malong 158m. Several patches of high electrical resistivity were found, and interpreted as patches of sporadic permafrost. The lower limits of sporadic to discontinuous permafrost in the area are confirmed by the presence of permafrost-related landforms nearby. There is a close correspondence between moss patches and permafrost patches along the geoelectrical transect

    Modelos para optimizar adquisición y almacenamiento de materias primas agroindustriales

    Get PDF
    177 p.En este trabajo se presenta dos modelos de optimización para apoyar decisiones de planificación para la adquisición y almacenaje de materia prima de plantas de proceso agroindustriales, una parte de la cadena de suministro agroindustrial. Los modelos propuestos corresponden a un problema de Programación Lineal Entera Mixta que busca minimizar los costos de adquisición, transporte desde los huertos a la planta y seleccionar la mejor relación de calidad de la materia prima, esto para el modelo de retiro, y costos de almacenamiento, transporte desde la planta a los centros de almacenamiento y el almacenaje diferenciado de las materias primas para el modelo de almacenamiento, sujeto a restricciones de demanda de las plantas agroindustriales, oferta de los productores, variedades de materia prima existentes en los productores y calidades de las materias primas para el modelo de retiro, y restricciones de capacidad de los centros de almacenaje y variedad de materia prima única de almacenamiento por centro para el modelo de almacenamiento. El modelo de retiro entrega la selección de productores a los cuales se deben adquirir las variedades de materias prima para cumplir el plan anual de abastecimiento y el modelo de almacenamiento entrega los centros de almacenamientos necesarios para colocar las materias primas antes de ser enviadas a los procesos productivos. Los modelos fueron aplicados a tres temporadas de proceso de una planta agroindustrial de la Región del Maule (temporadas 2008, 2009 y 2010). Los resultados obtenidos por el modelo de retiro en forma global se tiene una disminución de costos totales de 4%, 9% y 9%, respectivamente, representados en ahorros monetarios de MM102,MM 102, MM 77 y MM98,respectivamente.Losresultadosobtenidosporelmodelodealmacenamientoenformaglobalsetieneunadisminucioˊndecostostotalesde20 98, respectivamente. Los resultados obtenidos por el modelo de almacenamiento en forma global se tiene una disminución de costos totales de 20%, 15% y 22%, respectivamente, representados en ahorros monetarios de MM 28, MM14yMM 14 y MM 33, respectivamente. Palabras Claves: Planificación de retiro, Planificación de almacenamiento, Cadena de suministro:ABSTRACT: This paper presents two optimization models to support planning decisions for the acquisition and storage of raw material for agro-processing plants, part of the agribusiness supply chain. The proposed model to a problem of Mixed Integer Linear Programming that seeks to minimize acquisition costs, transportation from the orchards to the plant and select the best quality raw material, this model for the removal and storage costs, transport from the plant to storage facilities and storage differentiated raw materials for the storage model, subject to demand constraints of the agro-industrial plants, supply of providers, a variety of existing raw material suppliers and qualities raw materials for the model of retirement, and capacity constraints of storage centers and unique variety of raw materials storage center for the storage model. The retirement model delivers the selection of suppliers to which they must purchase raw materials varieties to meet the annual supply and delivery storage model storage facilities required to get the raw materials before being sent to the processes productive. The models were applied to three-year process of agro-industrial plant in the Region of Maule (seasons 2008, 2009 and 2010). The results obtained by the model of retirement as they have reduced overall total cost of 4%, 9% and 9%, respectively, represented in monetary savings of MM102,MM 102, MM 77 and MM98respectively.Theresultsofthestoragemodelhasaloweroveralltotalcostof20 98 respectively. The results of the storage model has a lower overall total cost of 20%, 15% and 22%, respectively, represented in monetary savings of MM 28, MM14andMM 14 and MM 33 respectively. Keywords: Retirement planning, storage planning, supply chai

    Cádiz, una economía por descubrir

    Get PDF
    Este trabajo intenta avanzar en el análisis de la economía de la provincia de Cádiz desde el siglo XIX hasta el XXI, poniendo en evidencia la función de los factores de desarrollo provinciales y la débil integración de las medidas de política económica de localización industrial en el entorno económico existente.This work tries to make advance the analysis of the evolution of the economy in the province of Cadiz, from the XIXth century to the XXIst century, putting forth the role of the factors of provincial development and the low integration of the measures oftheeconomical policyof industrial localisation in the existent economical environement

    Atmospheric emissions of volatile organic compounds from a mine soil treated with sewage sludge and tomato plants (Lycopersicum esculentum l.)

    Get PDF
    The study investigated the emissions of volatile organic compounds (VOCs) from a mining soil amended with sewage sludge and irrigated with wastewater with or without tomato plants. The aim is to find out whether amendment and irrigation change VOC emissions from the soil and whether tomato changes emissions compared to uncultivated soil. Soil and plant experiments were done in assembled pots. All pots were placed inside a closed glass chamber inside an isolated and windowless room. Experiments with soil without plants were done independently from experiments with soil and plants. An aspirating pump coupled with Tenax adsorbent tubes was used for sampling of VOCs emitted from pots. Volatile organic compounds trapped in the tubes were quantified by gas chromatography–mass spectrometry detection. The study detected a total of nine VOCs emitted from the polluted soil: benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, styrene, benzene-1,2,4-trimethyl and tetrachloroethylene, among which the most abundant were toluene, m-xylene and styrene. Differences between pots with or without amendments (C and A-pots) showed a general tendency to a decline of VOCs emissions in the mining soil amended with sewage sludge. Plants contributed to increase significantly the emissions of all VOCs in both A and C-pots. The soil amended with sewage sludge reduced the emission of VOCs: styrene in pots without plants and benzene and xylenes in pots with plants. Tomato plants contributed to increase significantly the emissions of all VOCs except styrene in both amended and non-amended soils. © 2022, The Author(s).Junta de Andalucía P10-RNM5814European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER) P10-RNM581

    Volatile organic compounds removal by means of a felt-based living wall to improve indoor air quality

    Get PDF
    Currently, the population spends most of the time in indoor environments, which makes Indoor Air Quality (IAQ) very important for health and comfort. As vegetation can act as a biofilter capturing air pollutants, this study aims to assess the effectiveness of a living wall module in the removal of the Total Volatile Organic Compounds (TVOCs) for IAQ improvement. An airtight glass chamber was used to release contaminants, monitoring the TVOCs both with the chamber empty (control) and with a small Fytotextile® living wall module planted with Nephrolepis exaltata L. A substantial reduction of TVOCs was observed when the living wall was inside the chamber. In few hours, TVOCs levels were reduced below the recommended limit (following Spanish regulations). More tests are recommended considering different plant species and other variables related to the IAQ.Junta de Andalucía - P18-TP-165

    Aligning rTWT with 802.1Qbv: a Network Calculus Approach

    Get PDF
    Industry 4.0 applications impose the challenging demand of delivering packets with bounded latencies via a wireless network. This is further complicated if the network is not dedicated to the time critical application. In this paper we use network calculus analysis to derive closed form expressions of latency bounds for time critical traffic when 802.11 Target Wake Time (TWT) and 802.1Qbv work together in a shared 802.11 network

    The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.

    Get PDF
    Nitrogen balance studies have shown that a portion of the N ingested but not excreted is not accounted for. We compared several diets (standard, high-fat, high-protein, and self-selected cafeteria) to determine how diet-dependent energy sources affect nitrogen handling, i.e., the liver urea cycle. Diet components and rat homogenates were used for nitrogen, lipid, and energy nalyses. Plasma urea and individual amino acids, as well as liver urea cycle enzyme activities, were determined. Despite ample differences in N intake, circulating amino acids remained practically unchanged in contrast to marked changes in plasma urea. The finding of significant correlations between circulating urea and arginine-succinate synthase and lyase activities supported their regulatory role of urea synthesis, the main N excretion pathway. The cycle operation also correlated with the food protein/energy ratio, in contraposition to total nitrogen losses and estimated balance essentially independent of dietary energy load. The different regulation mechanisms observed have potentially important nutritional consequences, hinting at nitrogen disposal mechanisms able to eliminate excess nitrogen under conditions of high availability of both energy and proteins. Their operation reduces urea synthesis to allow for a safe (albeit unknown) mechanism of N/energy excess accommodation

    TRIM: An architecture for transparent IMS-based mobility

    Get PDF
    In recent years, the development and deployment of new wired and wireless access net work technologies have made the ubiquitous Internet a reality. Users can access anywhere and anytime to the broad set of value added Internet services, which are delivered by means of the IP protocol. In this context, 3GPP is currently developing the IP Multimedia Subsystem (IMS), as a key element that allows to evolve from the ubiquitous access to the Internet services towards a next generation network model, by providing a set of essen tial facilities such as session control, QoS, charging and service integration. Nevertheless, several open issues still need consideration before the future Internet becomes real, such as supporting user mobility in IP networks. Although mobility support in the Internet is receiving much attention, IMS networks present inherent particularities that require fur ther analysis. The solutions proposed so far for IMS do not support mobility transparently to the end user applications, or address the problem by introducing complex changes to the IMS infrastructure. This paper presents TRIM, an architecture for transparent IMS based mobility. TRIM supports mobility in IMS networks transparently to the end user applications, which are unaware of the handover management procedures executed between the mobile node and the network. We have performed several experiments with a TRIM prototype, using a real IMS testbed with 3G and WLAN access networks, validating the proposal for UDP and TCP based applications.European Community's Seventh Framework ProgramPartially granted by the Madrid Community through the MEDIANET project (S 2009/TIC 1468)Publicad

    A solution for transparent mobility with route optimization in the IP multimedia subsystem

    Get PDF
    This paper presents TRIM+, an architecture for transparent mobility management with route optimization in IMS based networks. The design of our architecture is based on a previous work referred to as TRIM. TRIM was originally devised to provide transparent mobility support in the IMS, although transparency came at the cost of using a suboptimal data path between communicating end points. TRIM+ maintains transparency as a design criterium, and thus end-user applications, running at the mobile node and its correspondent communication peers, are unaware of mobility management procedures. Additionally, the proposed design defines a set of route optimization procedures, allowing compliant devices to use the optimal data path for media communications. Furthermore, TRIM+ addresses packet loss management in scenarios where the media path cannot be maintained during the handover of the MN. To this end, our architecture enables the MN to request buffering capacity in its home network to temporarily store incoming media traffic during the handover, which would otherwise be dropped. This mechanism, as well as route optimization procedures, are executed transparently to the end-user applications running at the communicating end points. As a proof-of-concept, we have implemented a software prototype of the TRIM+ architecture, deploying it over a real IMS testbed. By means of a set of experiments, we have validated the mechanisms proposed in this paper, considering both UDP and TCP user traffic.This article has been partially granted by the Madrid Commu nity through the MEDIANET project (S 2009/TIC 1468), and by the European Community through the CROWD project (FP7 ICT 318115). The work of Ignacio Soto has been partially sup ported through the I MOVING project (TEC2010 18907).Publicad

    IEEE 802.11az Indoor Positioning with mmWave

    Full text link
    Last years we have witnessed the uprising of location based applications, which depend on the devices ability to accurately obtain their position. IEEE 802.11, foretelling the need for such applications, started the IEEE 802.11az work on Next Generation Positioning. Although this standard provides positioning enhancements for sub-6GHz and mmWave bands, high accuracy in the order of centimeters can only be obtained in the latter band, thanks to the beamforming information available at mmWave operation. This work presents a detailed analysis on the new techniques provided by IEEE 802.11az for enhanced secured positioning in the mmWave band, assessing them through experimentation.Comment: 8 pages, 6 figures, magazine submissio
    corecore