1,285 research outputs found

    ANÃLISIS DE FACTIBILIDAD PARA LA INTRODUCCIÓN DEL BIODIESEL EN ECUADOR

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    Increases in petroleum prices have affected the prices of its derived products. In addition, the interest in issues related to the environment and energy security at world-wide level has been increased. All of these factors have contributed to the development of alternative fuel such as the ethanol, biodiesel and natural gas. This study analyzes the main agricultural products used to produce biodiesel, their production costs and the utilization of those inputs in other industries. This study will also include a brief summary of different legislations in those countries under analysis. On the other hand, we will find break-even points and apply a sensibility analysis associated with distinct scenarios in terms of input-output prices.Biofuels, biodiesel, feasibility, legislations, break-even points., Agribusiness,

    MANAGEMENT ACCOUNTING USES: EMPIRICAL EVIDENCE WITHIN INTERORGANIZATIONAL RELATIONSHIPS

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    Conversely to previous research focused in the study of only one use of management accounting systems (MAS) in interorganizational relationships, we develop a model to explore the interaction of both uses (decision control – decision management) offering empirical evidence through a survey in the relationship between a manufacturing firm and its outsourced firms. Through two MAS tools, designed and shared by the manufacturer, both parties inform about their use and their perception of the partner's use. The results show that the perceptions mediate the interaction between both uses, finding discrepancies between real use and perception. It is evidenced that the perception of the decision control of outsourced firms do not harm their decision management, strengthening the theory that both uses can be complementary and that a MAS can supervise partners without damage their use to improve their daily managememt.management accounting functions, interorganizational relationships.

    Updates of the in-gel digestion method for protein analysis by mass spectrometry

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    The in‐gel digestion of proteins for analysis by liquid chromatograph mass spectrometry has been used since the early 1990s. Although several improvements have contributed to increasing the quality of the data obtained, many recent publications still use sub‐optimal approaches. We present updates of the in‐gel digestion protocol. We show that alternative reducing, alkylating agent reactions and tryptic digestion buffers increase peptide and protein identification and reduce incubation times. Our results indicate that a simultaneous and short, high temperature reduction and alkylation reaction using Tris(2‐carboxyethyl)phosphine hydrochloride (TCEP) and chloroacetamide (CAA) with a subsequent gel wash improve protein identification and sequence coverage, diminish peptide side reactions. Additionally, use of 4‐(2‐Hydroxyethyl)piperazine‐1‐ethanesulfonic acid buffer (HEPES) allows a significant reduction in the digestion time improving trypsin performance and increasing the peptide recovery. The updates of the in‐gel digestion protocol described here are efficient and offer flexibility to be incorporated in any proteomic laboratory

    Aplicaciones eléctricas del acrilonitrilo butadieno estireno (ABS) reforzado con neumáticos fuera de uso (GTR)

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    La masiva fabricación de neumáticos, así como su posterior almacenamiento una vez utilizados, constituye un grave problema medioambiental al que se intenta dar salida de diversas formas, entre las que se encuentra el mezclar estos neumáticos fuera de uso (old used tires, GTR) con diferentes polímeros termoplásticos y termoestables. Estas mezclas se realizan variando el tratamiento previo al que se somete el GTR, el grado de desvulcanizado, las condiciones de mezcla o prensado, etc. Posteriormente, se analizan estas mezclas estructural y mecanicamente, buscando posibles aplicaciones industriales para ellas. El presente trabajo, pretende conseguir materiales aptos para la industria eléctrica a partir de la mezcal del Acrilonitrilo butadieno estireno (ABS) reutilizado con neumáticos fuera de uso (GTR), pero partiendo del requisito de unos mínimos costes de reciclado posibles, es decir, utilizando GTR vulcanizado y sin aplicar ningún pretratamiento previo, y en cambio, actuando sobre el tamaño de sus partículas, el cual se puede conseguir con un simple y economico tamizado. Otra novedad que introduce el presente estudio, es el elevado número de compuestos analizados, aparte del profundo analisis a los que se les ha sometido (dieléctrico, mecánico, térmico y de microestructura), obteniendose de cada ensayo una gran cantidad de variables. Los compuestos se obtuvieron tomando como variables los tres tamaños de particula del GTR (p<200μm, 200<p<500μm, y p>500μm), y las siete concentraciones de GTR en la mezcla (0%, 5%, 10%, 20%, 40%, 50% y70%), lo que representa, un total de 21 nuevos compuestos. Aparte, para que los ensayos dieléctricos fueran lo más exhaustivos posibles y mostraran el comportamiento del compuesto en condiciones muy diversas, se consideró un amplio régimen de temperaturas (30ºC hasta 120ºC) así como de frecuencias (1・10  -2 Hz hasta 3・106 Hz). Todos estos datos, han permitido caracterizar con bastante exactitud las propiedades de los nuevos compuestos, y dependiendo de estos resultados, se han buscado posibles aplicaciones eléctricas, con el requisito de que estas debían ajustarse a las Normativas Oficiales

    Stainless Steel Voltammetric Sensor to Monitor Variations in Oxygen and Humidity Availability in Reinforcement Concrete Structures

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    [EN] The present work presents the results obtained with a stainless steel (SS) voltammetric sensor to detect variations in humidity (H2O) and oxygen (O2) availability in concretes. First, studies in solution were run by preparing several solutions to represent the different conditions that can be found in concrete pores. Second, the sensor's response was studied by varying O2 availability by argon or synthetic air bubbling. Then concrete conditions with different degrees of carbonation were simulated using solutions with a pH between 13 and 8.45. After characterization in solution, a study by means of concrete samples with several water/cement ratios (0.6, 0.5 and 0.4) was performed, in which sensors were embedded and studied under different O2 and H2O saturation conditions. The obtained results revealed that with the voltagram, it is possible to evaluate O2 availability variation from the slopes of the lines identified logarithmically in the voltagram for the obtained cathodic sweeping. All the results obtained with the sensor were correlated/validated by standard assays to characterize porosity in hardened concretes.The authors would like to express their gratitude to the Spanish Ministry of Science and Innovation for the pre-doctoral scholarship granted to Ana Martinez Ibernon (FPU 16/00723). To the Universitat Politecnica de Valencia for the financial support in the project "Ayudas a Primeros Proyectos de Investigacion (PAID-06-18): Lengua Electronica Voltametrica para el control de durabilidad en hormigones, SP20180245"Martínez-Ibernón, A.; Lliso-Ferrando, JR.; Gandía-Romero, JM.; Soto Camino, J. (2021). Stainless Steel Voltammetric Sensor to Monitor Variations in Oxygen and Humidity Availability in Reinforcement Concrete Structures. Sensors. 21(8):1-21. https://doi.org/10.3390/s21082851S12121

    Overload and short-circuit protection strategy for voltage source inverter-based UPS

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    Acute effects of different external compression with blood flow restriction on force-velocity profile during squat and bench press exercises

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    The aim was to compare the acute effects of bench press (BP) and squat (SQ) exercises with blood flow restriction (BFR) (40%, 60%, 80% and 100% of the complete arterial occlusion pressure (AOP)) and without BFR (CON) on the mean propulsive (VelMED) and maximum (VelMAX) bar velocity. Fourteen healthy, physically active males (age, 23.6±4.1 years; height, 1.85±0.11 m; body weight 85.4±4.1 kg) took part in the study. There was one set for each testing condition (CON, 40%, 60%, 80% and 100%) with 6 repetitions for BP and 6 repetitions for SQ, at 60% of 1RM, and 3 minutes of recovery between sets. The results showed statistically significant differences of the sets with 80% BFR vs. CON (mean difference [MD] = 0.035 m·s-1, p < 0.05, ES = 0.52 [1.02–0.03]) and 100% BFR sets vs. CON (MD = 0.074, p < 0.001, ES = 1.08 [1.79–0.38]) for BP. In the SQ exercise, statistically significant differences were found between 100% BFR vs. CON (DM = 0.031 m·s-1, p < 0.05), vs. 100% BFR 40% (MD = 0.04 m·s-1, p < 0.05). Trend analysis showed a statistically significant linear trend (F[1,9] = 34.9, p < 0.001, F[1,13] = 27.32, p < 0.001) for the VelMED in relation to the different levels of BFR. In conclusion, our results showed that BFR levels above ~80% AOP (BP) and ~100% AOP (SQ) produce a VelMED improvement at 60% 1RM

    OC, HPC, UHPC and UHPFRC Corrosion Performance in the Marine Environment

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    [EN] This work aims to study the corrosion performance of six concretes in the marine environment: three ordinary concretes (C30, C40 and C50); one high-performance concrete (C90); two ultra high-performance concretes, one without fibres (C150-NF) and another one with steel fibres (C150-F). To this end, porosity and chloride ingress resistance were analysed at different ages. Resistivity was also evaluated and the corrosion rate in the embedded rebars was monitored. The results showed that C30, C40 and C50 had porosity accessible to water percentages and capillary absorption values between six- and eight-fold higher than C90 and C150-NF and C150-F, respectively. Similar differences were obtained when oxygen permeability was analysed. Chloride ingress resistance in the ordinary concretes was estimated to be one-fold lower than in C90 and two-fold lower than in C150-NF and C150-F. Presence of fibres in C150-F increased the diffusion coefficient between 5% and 50% compared to C150-NF. Fibres also affected resistivity: C150-NF had values above 5500 ohm m, but the C150-F and C90 values were between 700 and 1000 ohm m and were one-fold higher than the ordinary concretes. After 3 years, the corrosion damage in the embedded rebars exposed to a marine environment was negligible in C90, C150-NF and C150-F (9.5, 6.2 and 3.5 mg mass loss), but with higher values (between 170.4 and 328.9 mg) for C3, C40 and C50. The results allow a framework to be established to make comparisons in future studies.This research was funded by the Spanish Government, grant number PID2020-119744RB-C21 funded by MCIN/AEI/10.13039/501100011033Lliso-Ferrando, JR.; Gandía-Romero, JM.; Soto Camino, J.; Valcuende Payá, MO. (2023). OC, HPC, UHPC and UHPFRC Corrosion Performance in the Marine Environment. Buildings. 13(10):1-27. https://doi.org/10.3390/buildings13102439127131

    Generic multisensor multitarget bias estimation architecture

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    Current bias estimation algorithms for air traffic control (ATC) surveillance are focused on radar sensors, but the integration of new sensors (especially automatic dependent surveillance-broadcast and wide area multilateration) demands the extension of traditional procedures. This study describes a generic architecture for bias estimation applicable to multisensor multitarget surveillance systems. It consists on first performing bias estimations using measurements from each target, of a subset of sensors, assumed to be reliable, forming track bias estimations. All track bias estimations are combined to obtain, for each of those sensors, the corresponding sensor bias. Then, sensor bias terms are corrected, to subsequently calculate the target or sensor-target pair specific biases. Once these target-specific biases are corrected, the process is repeated recursively for other sets of less reliable sensors, assuming bias corrected measures from previous iterations are unbiased. This study describes the architecture and outlines the methodology for the estimation and the bias estimation design processes. Then the approach is validated through simulation, and compared with previous methods in the literature. Finally, the study describes the application of the methodology to the design of the bias estimation procedures for a modern ATC surveillance application, specifically for off-line assessment of ATC surveillance performance

    Experimentel ADS-B based surveillance

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    This paper describes an ADS-B implementation in air-to-air and ground based experimental surveillance within a prototype ATM system. The relations between airborne and ground systems related to surveillance are detailed, and the prototype surveillance systems and their algorithms described. Their performance is analysed, based both on simulated and real data
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