Analysis of the Behaviour of Biofuel-Fired Gas Turbine Power Plants

The utilisation of biofuels in gas turbines is a promising alternative to fossil fuels for power generation. It would lead to significant reduction of CO2 emissions using an existing combustion technology, although significant changes seem to be needed and further technological development is necessary. The goal of this work is to perform energy and exergy analyses of the behaviour of gas turbines fired with biogas, ethanol and synthesis gas (bio-syngas), compared with natural gas. The global energy transformation process (i.e. from biomass to electricity) has also been studied. Furthermore, the potential reduction of CO2 emissions attained by the use of biofuels has been determined, considering the restrictions regarding biomass availability. Two different simulation tools have been used to accomplish the aims of this work. The results suggest a high interest and the technical viability of the use of Biomass Integrated Gasification Combined Cycle (BIGCC) systems for large scale power generation

Neoformación de minerales de la arcilla en la España Peninsular: tendencias termidinámicas basadas en la composición de las aguas de los ríos españoles

[Abstract] Stable or metastabie minerals are established for 381 sampling points from river water compositions for every spanish watershed aiong the years 1974-75, 1975-76, 1981-82, 1982-83 and 1983-84, as published by the spanish Department of Public Works. Phase diagrams for the systems SiO2-Al2O3-H2O, K2O-SiO2-Al2O3-H2O, Na2O-SiO2-Al2O3-H2O, MgO-SiO2-Al2O3-H2O, and CaO-SiO2-Al2O3-H2O, for 298 K and 1 atm. conditions, are used in order to determine the mineraiogical stability, and therefore neoformation trends. Stable and metastable phases were taken into account to draw the diagrams (Fernandez Marcos and Macias, 1987). The prevailing trend in the Peninsula, according to this method, is towards kaolinite neoformation. Nevertheless differences are observed between watersheds. So kaolinite is the only stable mineral neoformed in the North watersheds while there exist severa! stable minerals (kaolinite, mica, (kaolinite, mica, chlorite, pyrophillite) or metastable ones (smectite) in the Tajo, Guadiana, Guadalquivir, South, Jucar, Segura and East Pyrenees watersheds, depending on sampling point and date. Geographic distribution of different minerals is satisfactorily explained by taking into account: rainfall distribution, sileceous or calcareous nature of ground, and upper, medium or lower position in the river course

Estado de degradación proteolítica del queso de Los Pedroches

Las imágenes electroforéticas en gel de poliacrilamida de seis muestras de quesos de los Pedroches maduros, elaborados por diferentes productores, indican que la as-caseína aparece más degradada en todos los quesos que la B-caseína, que apenas es hidrolizada en algunos quesos. La hidrólisis enzimática de la as-caseína (fundamentalmente de la as2- y as3-) origina cuatro productos de escisión de mayor movilidad. La degradación proteolítica de la B-caseína rinde siete fragmentos polipeptídicos de alto peso molecular y baja movilidad electroforética, que se sitúan en la región de la K • y y-caseína. Algunos de estos polipéptidos pueden corresponder a caseínas minoritarias equivalentes a la y-,, TS- y R-caseína eencontradas en qquesos maduros eelaborados con leche de vaca

Principales componentes químicos y parámetros físicos del queso de Los Pedroches

Se ha determinado la composición química bruta, los principales componentes mmerales y dos parámetros físicos, el pH y la ow, de un lote heterogéneo de 16 quesos de Los Pedroches maduros, elaborados todos eUos por productores diferentes. Los valores medios hallados, que pueden considerarse como representativos de esta variedad de queso, han sido: humedad 34,5 O/o, proteínas 3 1,7 0/o, gras:J 26,7 Ofo, ácido láctico 1,5 0/o y cenizas 6,3 0/o. Sobre la base de la m~tcria seca, el contenido medio en sal es del 4,8 0/o, el de calcio de 1 ,S 0/o y el de fósforo de 1,2 Ofo (relación Ca/1' = 1,27). El valor pll medio es de 5,45 y la aw de 0,90

Introducing a new dosimeter for the assessment and monitoring of vocal risk situations and voice disorders

Summary: Purpose. There are many physiological parameters recorded by devices that are becoming more affordable, precise and accurate. However, the lack of development in the recording of voice parameters from the physiological or medical point of view is striking, given that it is a fundamental tool for the work of many people and given the high incidence and prevalence of voice pathologies that affect people’s communication. In this paper we perform a complete literature review on the dosimeters used in voice research and to present a pro- totype dosimeter with a pilot study to show its capabilities. Method. We conducted a literature review using the keywords [MONITORING], [PHONATION], [ACCU- MULATOR], [PORTABLE], [DOSIMETRY], [VOICE] searching in PubMed, Trip Database, HONcode, and SciELO search engines. From our review of dosimeter designs, we created our own prototype consisting of two main components: a Knowles Electronics BU-7135-0000 accelerometer mounted on a neck brace; and the ultra- low power MSP430FR5994 microcontroller. The selected sampling frequency was 2048 Hz. The device calculates the F0 every 250 ms and the amplitude and phonation activity every 31.25 ms. A pilot study was conducted using 2 subjects: one male during 11 days and one female during 14 days. Results. This work includes devices that have been created during the last 45 years as tools for the diagnosis and monitoring of the treatment of cases of vocal pathology and for the detection of phonatory patterns or risk situa- tions for developing voice disorders or vocal pathologies. We also present recordings with our new device on the pattern of daily talk time, the fundamental frequency and the relative intensity of two subjects on different days. Conclusions. Interesting work has been done in the development of voice dosimeters with different approaches. In our experience it is not possible to access them for research and they are not yet in clinical use. It is possible that a joint approach with voice and voice disorders professionals and engineers working closely together could take advantage of current technology to develop a fully portable, useful, and efficient system

Nutrient availability and climate as the main determinants of the ratio of biomass to NPP in woody and non-woody forest compartments

Key message: Once the effect of stand age has been taken into account, nutrient availability and climate play a crucial role in determining the B:NPPs of woody and non-woody tissues. - Abstract: Forest ecosystems accumulate large amounts of carbon in living tissues. The residence time of this carbon in the ecosystem depends largely on the turnover time of these tissues, which can be estimated as a surrogate of the ratio of biomass to net primary production (B:NPP). We used a global forest database of 310 sites containing data for biomass stocks and NPP to investigate the differences of B:NPPs among species and forest compartments and to determine B:NPPs main exogenous (mainly climate and nutrient availability) and endogenous (leaf habit and stand age) drivers. We used asymptotic exponential functions to adjust the B:NPPs of woody compartments to a theoretical stationary state to allow comparisons between forests of different ages. The B:NPPs of woody tissues (branches, stems, and coarse roots) were positively influenced by stand age, conversely to fine roots and leaves, which were weakly dependent on the age of the forest. The B:NPPs of woody tissues were positively correlated with nutrient availability, whereas fine-root B:NPPs decreased with increasing nutrient availability. The foliar B:NPP of evergreen forests was positively correlated with water deficit, and the fine-root B:NPP was correlated positively with the seasonality of precipitation and with annual thermal amplitude but negatively with water deficit. Our results support the influence of climate on the B:NPPs of non-woody compartments and identify nutrient availability as the main influence on the B:NPPs of woody tissues

Comparative study of AR versus video tutorials for minor maintenance operations

[EN] Augmented Reality (AR) has become a mainstream technology in the development of solutions for repair and maintenance operations. Although most of the AR solutions are still limited to specific contexts in industry, some consumer electronics companies have started to offer pre-packaged AR solutions as alternative to video-based tutorials (VT) for minor maintenance operations. In this paper, we present a comparative study of the acquired knowledge and user perception achieved with AR and VT solutions in some maintenance tasks of IT equipment. The results indicate that both systems help users to acquire knowledge in various aspects of equipment maintenance. Although no statistically significant differences were found between AR and VT solutions, users scored higher on the AR version in all cases. Moreover, the users explicitly preferred the AR version when evaluating three different usability and satisfaction criteria. 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Tool-path effect on the geometric deviations in the machining of UNS A92024 aeronautic skins

Traditionally, aeronautics skins are being machined by chemical milling, a high-pollutant process. An efficient alternative to this technology is conventional machining. However, to ensure the parts machined with this process keeps the industrial quality controls, the effect of tool-path might be characterized, specially analyzing final thickness and roughness. In this paper, five different tool-paths have been applied under the same machining parameters in the dry milling of Al-Cu UNS A92024 thin plates. Machining time, final thickness and roughness have been evaluated. Most roughness and thickness results are under the industrial quality limits stablished for this type of parts.This work has received financial support from Spanish Goverment (Project DPI2015-71448-R), TECNALIA Research & Innovation and the University of Cadiz (University training plan UCA/REC01VI/2016)

Time-resolved imaging of the laser forward transfer of liquids

Time-resolved imaging is carried out to study the dynamics of the laser-induced forward transfer of an aqueous solution at different laser fluences. The transfer mechanisms are elucidated, and directly correlated with the material deposited at the analyzed irradiation conditions. It is found that there exists a fluence range in which regular and well-defined droplets are deposited. In this case, laser pulse energy absorption results in the formation of a plasma, which expansion originates a cavitation bubble in the liquid. After the further expansion and collapse of the bubble, a long and uniform jet is developed, which advances at a constant velocity until it reaches the receptor substrate. On the other hand, for lower fluences no material is deposited. In this case, although a jet can be also generated, it recoils before reaching the substrate. For higher fluences, splashing is observed on the receptor substrate due to the bursting of the cavitation bubble. Finally, a discussion of the possible mechanisms which lead to such singular dynamics is also provided