680 research outputs found

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    Validity of water industry wastes in cement industry

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    This paper examines the validity of several water industry wastes to be reused in different stages of cement production. The wastes considered are: a drinking water treatment plant sludge (DWTP), a sewage sludge (SS) and a spent activated carbon. Different procedures of drying of wastes using a novel dry spray system or subjected to thermal drying or stabilization and dried with lime are analysed. The spray drying process was successfully used with the DWTP sludge (but not with SS). The material was not found to be suitable as a supplementary material in blended cements. Despite this, the spray dried sludge did show good potential as partial or full substitute for clay as a raw material in cement clinker manufacture. A novel thermally drying process (Turbo-drying RINA-JET) was applied to produce dried sewage sludge. The dry sludge consisted of 56 % organic matter and has a high calorific value (8291 J / g), making it valid as an alternative fuel. The ash (35% of dry SS) contains Ca, Fe, P, Si and Al as main inorganic elements which are incorporated into the clinker phases. The burnability of the raw mixture containing this SS sludge was better than in the control raw mix. Furthermore, the paper describes an industrial process for stabilising sewage sludge (SS) with lime and evaluates the viability of the stabilised product, referred to as “Neutral”, as a raw material in the production of Portland cement clinker for the cement industry. The proposed process for sewage sludge treatment has a number of advantages over traditional treatments. In the Basic plant design, the chemical energy in the reagents generates sufficient thermal energy for the moisture to evaporate. This makes the process more energy-efficient than others. The validity of the “Neutral” product as a starting material in raw mixes for the production of cement clinker by substitution of limestone is demonstrated. Regarding the validity of spent activated carbon as an alternative to pet coke as fuel in Portland cement kilns, the carbon differed substantially from the coke, having lower calorific value (18 % less). However, the qualities of the spent coke were still sufficient for the intended use. The ash fraction of the spent activated carbon was mainly composed of anhydrite and quartz (SO3 = 14.1 %) and it is included into the clinker phases during the burning. The SO3 from the ashes promotes a very large growth in alite crystals in the clinker

    Ahorro de energía en la clinkerización empleando CaF2 y CaS04 como mineralizadores. Estudio de la fluorellestadita

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    Not availableEl clínker portland está compuesto esencialmente por cuatro fases: alita, belita, fase alumínica y fase ferrítica, que se corresponden de forma aproximada con C3S, C2S, C3A y C4AF (*), respectivamente. Estas dos últimas ("fundentes") tienen como misión principal el facilitar la formación de los hidráulicamente activos, C3S y C2S. Es decir, su aportación a las resistencias mecánicas del cemento hidratado es prácticamente despreciable. Aquellas fases (C3A y C4AF) se forman en el horno a partir de los crudos empleados (generalmente caliza y arcilla); su coste energético es elevado ya que además del que precisan para su síntesis les es necesaria una alta proporción de CaO. Este óxido proviene a su vez de la descarbonatación del CaC03, que es el proceso químico que mayor energía consume en la clinkerización. Por ello, una forma que a priori sería válida para ahorrar energía en la fabricación de cemento es la de sustituir total o parcialmente la "fase líquida" (C3A + C4AF) tradicional por otra que no precisara tanto CaO, ni que se formara con tan elevado gasto de energía

    Evaluation of a lime-mediated sewage sludge stabilisation process. Product characterisation and technological validation for its use in the cement industry

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    This paper describes an industrial process for stabilising sewage sludge (SS) with lime and evaluates the viability of the stabilised product, denominated Neutral, as a raw material for the cement industry. Lime not only stabilised the sludge, raised the temperature of the mix to 80-100 °C, furthering water evaporation, portlandite formation and the partial oxidation of the organic matter present in the sludge. Process mass and energy balances were determined. Neutral, a white powder consisting of portlandite (49.8%), calcite (16.6%), inorganic oxides (13.4%) and organic matter and moisture (20.2%), proved to be technologically apt for inclusion as a component in cement raw mixes. In this study, it was used instead of limestone in raw mixes clinkerised at 1400, 1450 and 1500 °C. These raw meals exhibited greater reactivity at high temperatures than the limestone product and their calcination at 1500 °C yielded clinker containing over 75% calcium silicates, the key phases in Portland clinker. Finally, the two types of raw meal (Neutral and limestone) were observed to exhibit similar mineralogy and crystal size and distribution. © 2011.Peer Reviewe

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

    Graph based study of allergen cross-reactivity of plant lipid transfer proteins (LTPs) using microarray in a multicenter study.

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    The study of cross-reactivity in allergy is key to both understanding. the allergic response of many patients and providing them with a rational treatment In the present study, protein microarrays and a co-sensitization graph approach were used in conjunction with an allergen microarray immunoassay. This enabled us to include a wide number of proteins and a large number of patients, and to study sensitization profiles among members of the LTP family. Fourteen LTPs from the most frequent plant food-induced allergies in the geographical area studied were printed into a microarray specifically designed for this research. 212 patients with fruit allergy and 117 food-tolerant pollen allergic subjects were recruited from seven regions of Spain with different pollen profiles, and their sera were tested with allergen microarray. This approach has proven itself to be a good tool to study cross-reactivity between members of LTP family, and could become a useful strategy to analyze other families of allergens

    CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

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    Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research
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