1,989 research outputs found
Environmental impact assessment of R-152a as a drop-in replacement of R-134a in a domestic refrigerator
No full textIn the European Union F-gas Regulation limited the use of some refrigerants in several applications. Regarding the domestic refrigeration sector, the F-gas Regulation banned the use of refrigerants with GWP values higher than 150. This fact led the scientific community to search for a replacement of R-134a, that is the most common refrigerant used in domestic refrigerators in USA. In this work, a comprehensive environmental analysis of the drop-in substitution of R-134 with a low GWP refrigerant (R-152a) in a no-frost domestic refrigerator was performed. The comparison, based on experimental data, between the environmental performance of the refrigeration system with the two refrigerants was carried out developing two different evaluation methods, which led to the evaluation of TEWI and LCCP, respectively. Both these metrics consider both direct and indirect contributions to global warming. Historical data of different countries were used to forecast the carbon intensity values for the next 15 years, which were then used to evaluate indirect emissions of the system during its lifetime. Considering the Italian case study, the results showed that the refrigerator working with an optimal charge of R-152a, identified as the mass charge that minimises TEWI and/or LCCP index, has better environmental performance than the system working with R-134a, with a reduction of TEWI and LCCP values of 10.3% and 9.4%, respectively. The same comparison, in terms of LCCP, was also performed for other European countries, showing a strong dependence of the LCCP index on carbon intensity values
Diseño y desarrollo de un SGC según la norma UNE-EN ISO 9001:2008 en una empresa dedicada a la construcción de edificación residencial
No full textConsulta en la biblioteca ETSI Industriales (Riunet)Llopis Llopis, R. (2016). Diseño y desarrollo de un SGC según la norma UNE-EN ISO 9001:2008 en una empresa dedicada a la construcción de edificación residencial. https://riunet.upv.es/handle/10251/61794.Archivo delegad
Plaza de Toros Madrid : el jueves, 16 de junio de 1932 se verificará ... una gran corrida extraordinaria a beneficio de la Asociación Benéfica de Auxilios Mutuos de Toreros ...
No full textTexto del cartel: "Se lidiarán ocho toros, con divisa encarnada y amarilla de la acreditada ganadería del ... Marqués de Albayda, de Madrid ... Espadas [:] Manuel Mejías (Bienvenida), Jesús Solorzano, Domingo Ortega, Luis Gómez (El Estudiante) ... La corrida empezará a las cuatro y media en punto de la tarde ... "Se incluye un recuadro con el detalle de las normas que regirán la corrida (con referencia al Reglamento Taurino aprobado por Orden de 12 de julio de 1930) y una tabla con los precios de las localidadesAño tomado de la fecha de celebración de la corridaTipografía en tinta negra sobre papel verdeTítulo inserto en ilustraciónCon ilustración en la cabecera: "C. Ruano Llopis
The role of learning in innovation: in-house versus externally contracted R&D experience
No full textEn este trabajo se analiza el papel del aprendizaje en el éxito innovador de las empresas, tomando en consideración la naturaleza heterogénea de las actividades innovadoras, y en particular, distinguiendo entre el aprendizaje que proviene de la realización interna de actividades de I+D y el aprendizaje que proviene de la contratación externa de estas actividades. Para este trabajo se utiliza una muestra representativa de empresas manufactureras en España durante el período 1990-2006, y dentro del marco de una función de producción de innovaciones, se estiman modelos ¿count¿ con el fin de investigar la influencia que tiene en la obtención de resultados innovadores la experiencia que proviene de la I+D realizada dentro de la empresa y de la contratada externamente. Nuestros resultados muestran que el aprendizaje tiene un papel importante en la obtención de innovaciones de producto cuando las empresas organizan sus actividades de I+D internamente, y que la experiencia que proviene de la contratación externa de actividades de I+D no influye sobre el número de innovaciones de producto. This paper analyses the role of learning in firms¿ innovation success, taking into account the heterogeneous nature of innovation activities, and in particular, distinguishing between learning arising from the internal organization of R&D activities and learning from externally contracting these activities. We use a representative sample of Spanish manufacturing firms for the period 1990-2006, and within an innovation production function approach, we estimate count data models to investigate the influence of firms¿ in-house and externally contracted R&D experience in the achievement of innovative results. Our results show that learning is important in the achievement of product innovations when the firms organize R&D activities internally, and that experience from externally contracted R&D activities does not influence the number of product innovations.innovation, accumulation of knowledge, in-house R&D experience, externally contracted R&D experience, count data models. innovación, acumulación de conocimiento, experiencia en I+D interna, experiencia en I+D contratada externamente, modelos para datos ¿count¿.
The minimal resolution conjecture for points on del Pezzo surfaces
No full textMustaţǎ (1997) stated a generalized version of the minimal resolution conjecture for a set Z of general points in arbitrary projective varieties and he predicted the graded Betti numbers of the minimal free resolution of IZ. In this paper, we address this conjecture and we prove that it holds for a general set Z of points on any (not necessarily normal) del Pezzo surface X ⊆ P d - up to three sporadic cases - whose cardinality {pipe}Z{pipe} sits into the interval [P X(r - 1),m(r)] or [n(r),P X(r)], r ≥ 4, where P X(r) is the Hilbert polynomial of X, m(r):= dr 2 + r(2 - d) and n(r):= dr 2 + r(d - 2). As a corollary we prove: (1) Mustaţǎ's conjecture for a general set of s ≥ 19 points on any integral cubic surface in P 3; and (2) the ideal generation conjecture and the Cohen-Macaulay type conjecture for a general set of cardinality s ≥ 6d + 1 on a del Pezzo surface X ⊆ P d. © 2012 by Mathematical Sciences Publishers
Experimental evaluation of zeotropic refrigerants in a dedicated mechanical subcooling system in a CO2 cycle
No full textUse of zeotropic blends in the dedicated mechanical subcooling system of a CO2 refrigeration system was suggested as a possible improvement due to matching of evaporating temperature with CO2 temperature profile during subcooling. This work has verified this possibility and has determined theoretically the best performing compositions of R-600, R-32 and CO2 with the base fluid R-152a. Then, the mixtures have been tested experimentally in a lab-test bench for constant heat load temperature for three heat rejection temperatures (25.1, 30.3 and 35.1°C). Optimum conditions are measured (subcooling degree and heat rejection) and a COP increase of 1.4% has been obtained. The work, for the optimum conditions, analyses the operating parameters of the cycles and focus specially on the thermal parameters of the subcooler. It has been verified that the use of zeotropic mixtures allows to reduce irreversibilities in the cycle, as pointed out theoretically by Dai et al. (2018)
Señal Banda Base y Densidad Espectral de Potencia Asocidada
No full textLa figura muestra la señal banda base y su densidad espectral de potencia en función de los parámetros escogidoshttps://laboratoriosvirtuales.upv.es/eslabon/depsbbLlinares Llopis, R. (2009). Señal Banda Base y Densidad Espectral de Potencia Asocidada. https://riunet.upv.es/handle/10251/491
Experimental energetic analysis of the subcooler system in a two-stage refrigeration facility driven by a compound compressor
No full text[EN] This paper presents a detailed experimental analysis of the energetic effects of using a subcooler system in a two-stage refrigeration facility driven by a compound compressor. The analysis is carried out by comparing the experimental performance of the two-stage cycle working with the subcooler system to the experimental performance of the two-state cycle working without the subcooler system in an evaporating temperature range between -36 degrees C and -21 degrees C and in a condensing temperature range between 31 degrees C and 49 degrees C using R-404A as the working fluid. Experimental results show that the amount of refrigerant used to obtain the subcooling, which is injected between the compression stages, causes an increment in the interstage working pressure, in power consumption, and in the cooling capacity of the cycle. This paper discusses and analyzes these modifications.Torrella Alcaraz, E.; Llopis, R.; Cabello, R.; Sanchez, D. (2009). Experimental energetic analysis of the subcooler system in a two-stage refrigeration facility driven by a compound compressor. HVAC&R Research. 15(3):583-596. doi:10.1080/10789669.2009.10390852S58359615
BER Modulación QAM
No full textLa figura muestra la BER teórica de una modulación QAM para un conjunto de relaciones Eb/Nohttps://laboratoriosvirtuales.upv.es/eslabon/berQAMLlinares Llopis, R. (2010). BER Modulación QAM. https://riunet.upv.es/handle/10251/788
Tren de Deltas y Conformación de Señal Banda Base en el dominio del tiempo
No full textTren de Deltas y Conformación de Señal Banda Base en el dominio del tiempohttps://laboratoriosvirtuales.upv.es/eslabon/tempsbbLlinares Llopis, R. (2009). Tren de Deltas y Conformación de Señal Banda Base en el dominio del tiempo. https://riunet.upv.es/handle/10251/491
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