3,545 research outputs found

    Sorption of lead (Pb2+) from aqueous solutions using chars obtained in the pyrolysis of forestry pine, rubber tires and plastics

    Get PDF
    Carbonaceous solid products resulting from thermochemical processes (pyrolysis, gasification), commonly known as chars, are emerging as low-cost sorbents of metallic contaminants, being their effectiveness already demonstrated in several studies (Inyang et al., 2012; Fuente-Cuesta et al., 2012; Ko³odyñska et al., 2012; Quek and Balasubramanian, 2009; Devecia and Kar, 2013). Given the fact that the commercial viability of pyrolysis and gasification plants for the treatment and valorisation of waste streams are increasingly being demonstrated, it is expected that large amounts of solid chars will be available in a near future, as by-products or as main products (pyrolysis-carbonization). Chars may possess several characteristics which turn them effective as heavy metals sorbents: aromatic carbon matrix with relatively porous structures, the presence of functional groups or inorganic inclusions in the surface providing active sites to interact with metallic species (Inyang et al., 2012; Fuente-Cuesta et al., 2012; Ko³odyñska et al., 2012; Quek and Balasubramanian, 2009; Devecia and Kar, 2013; Lu et al., 2012). Lead (Pb2+) is considered as a priority substance in the field of European water policy (EU, 2000; EU, 2008) which means that measures shall be taken by the Member States to eliminate or reduce the water pollution caused by this pollutant in order to fulfill the emission/discharge limits legislated for this compound

    Standardization and optimization of an automotive components production line

    Get PDF
    Supported by the concepts and definitions of Standard Work methodology, which underpins Lean Thinking philosophy and Kaizen, the study described in this article was developed at a company in the automotive sector, more specifically directed at a production line manufacturing components for air-conditioning systems. The main objectives were to standardize operations, decrease or eliminate the number of activities those are not generating added-value, enhance productivity and associate continuous improvement actions to the processes at hand in order to eliminate waste. After the implementation of a few simple changes - the standardization of operations, adjustments and allocations of workstations – one was able to tailor the production objectives and cycle times to the line’s capacity. The productivity and efficiency of both machines and workers was also increased. Due to the elimination of waste and generation of value, from the customer’s perspective, one was able to raise the OEE (Overall Equipment Effectiveness) general average by 16%, from 70% to 86%.info:eu-repo/semantics/publishedVersio

    Implementing autonomous maintenance in an automotive components manufacturer

    Get PDF
    The automotive sector constitutes one of the most demanding activities in the global market, since it requires a constant increase in productivity, both in the automobile industry as well as in the companies whose manufacture its components. This sector is currently set within an economic framework where there is a relentless search for costs reduction and an increase in productivity with minimal investment. In order to meet these requirements, companies have sought to optimise their products and processes to ensure higher profits. This study was developed with the purpose of enhancing procedures in the maintenance sector regarding a company which supplies air-conditioning tubes to the automotive sector. The main objective was to increase its machines and equipment availability through the implementation of autonomous maintenance. Due to the undertaken improvements, there was a 10% increase in the monthly indicator of equipment availability on line AA3 at the company where the study was carried out. This, in turn, resulted in an increase of 8% in OEE (Overall Equipment Effectiveness) during the same time period, which was chiefly due to a reduction both in machine breakdown rates, as well as in the MTTR (Mean Time To Repair) on the same line.info:eu-repo/semantics/publishedVersio

    Activated carbons from the co-pyrolysis of rice wastes for Cr(III) removal

    Get PDF
    ABSTRACT: Rice husk and polyethylene were mixed (50 % w/w each) and submitted to a pyrolysis assay. Four physical activations with CO2 were performed on the resulting co-pyrolysis char (PC). The activation at 800 °C, for 4h, generated the activated carbon (PAC3) with the best textural properties. PC, PAC3 and a commercial activated carbon (CAC) were characterized and submitted to Cr(III) removal assays. PC had a high percentage of volatile matter that was removed after the physical activation, resulting in more available pores in the final material (PAC). In the Cr(III) removal assays, two S/L ratios were tested: 5 and 10 g L-1. PC did not remove any Cr(III) from the solutions, but PAC presented similar results to CAC. At the S/L of 5 g L-1, Cr(III) removal was of 58.5 % for PAC and 62.5 % for CAC, both by adsorption mechanism; at the S/L of 10 g L-1, Cr(III) removal was almost complete due to precipitation caused by pH increase. The highest uptake capacities were of 7.92 mg g-1 for PAC and 8.71 mg g-1 for CAC, at the S/L of 5 g L-1. The results indicated that PAC3 may be a viable alternative to CAC on Cr(III) removal from aqueous media.info:eu-repo/semantics/publishedVersio

    CORAM (COsmic RAy Mission): An outreach program one century after Pacini and Hess works

    Get PDF
    Abstract CORAM (COsmic RAy Mission) is an outreach program carried out by INFN and the University of Salento in close collaboration with high schools. Students and their teachers are involved in the design, construction, test and operation of detectors for the measurement of several properties of the cosmic ray flux. The results of a set of measurements, made with a first detector prototype at different altitudes and underground, will be described

    Cr(III) removal from synthetic and industrial wastewaters by using co-gasification chars of rice waste streams

    Get PDF
    ABSTRACT: Blends of rice waste streams were submitted to co-gasification assays. The resulting chars (G1C and G2C) were characterized and used in Cr(III) removal assays from a synthetic solution. A Commercial Activated Carbon (CAC) was used for comparison purposes. The chars were non-porous materials mainly composed by ashes (68.3-92.6% w/w). The influences of adsorbent loading (solid/liquid ratio - S/L) and initial pH in Cr(III) removal were tested. G2C at a S/L of 5 mg L-1 and an initial pH of 4.50 presented an uptake capacity significantly higher than CAC (7.29 and 2.59 mg g(-1), respectively). G2C was used in Cr(III) removal assays from an industrial wastewater with Cr(III) concentrations of 50, 100 and 200 mg L-1. Cr(III) removal by precipitation (uptake capacity ranging from 11.1 to 14.9mg g(-1)) was more effective in G2C, while adsorption (uptake capacity of 16.1 mg g(-1)) was the main removal mechanism in CAC.info:eu-repo/semantics/publishedVersio

    Numerical study of a thrombus migration risk in aneurysm after coil embolization in patient cases: FSI modelling

    Get PDF
    Purpose There are still many challenges for modelling a thrombus migration process in aneurysms. The main novelty of the present research lies in the modelling of aneurysm clot migration process in a realistic cerebral aneurysm, and the analysis of forces sufered by clots inside an aneurysm, through transient FSI simulations. Methods The blood fow has been modelled using a Womersley velocity profle, and following the Carreau viscosity model. Hyperelastic Ogden model has been used for clot and isotropic linear elastic model for the artery walls. The FSI coupled model was implemented in ANSYS® software. The hemodynamic forces sufered by the clot have been quantifed using eight diferent clot sizes and positions inside a real aneurysm. Results The obtained results have shown that it is almost impossible for clots adjacent to aneurysm walls, to leave the aneurysm. Nevertheless, in clots positioned in the centre of the aneurysm, there is a real risk of clot migration. The risk of migration of a typical post-coiling intervention clot in an aneurysm, in contact with the wall and occupying a signifcant percentage of its volume is very low in the case studied, even in the presence of abnormally intense events, associated with sneezes or impacts. Conclusions The proposed methodology allows evaluating the clot migration risk, vital for evaluating the progress after endovascular interventions, it is a step forward in the personalized medicine, patient follow-up, and helping the medical team deciding the optimal treatment.Universidade de Vigo/CISU

    Long-term Negative Psychological Impact of Presymptomatic Testing on Familial Amyloid Polyneuropathy: Efecto psicológico negativo a largo plazo de las pruebas genéticas presintomáticas en la polineuropatía amiloide familiar

    Get PDF
    http://sherpa.ac.uk/romeo/search.php?issn=2174-0550This study addresses the profile of at-risk subjects whose long-term psychological impact of presymptomatic testing (PST) for Familial Amyloid Polyneuropathy (FAP) TTR V30M is negative. The sample consisted of 177 subjects, aged over 20 years that were 50% at-risk for FAP, and performed the PST at least three years ago. Participants were contacted by mail, one time only, to answer the sociodemographic questionnaire and the Brief Symptom Inventory (BSI), the Self-Rating Anxiety Scale of Zung (SAS), and the Beck Depression Inventory (BDI). From the sample, 22.6% (BSI), 16.4% (SAS), and 9% (BDI) subjects presented negative psychological impact, after having performed the PST for more than 3 years. Subjects with clinically significant values in BSI, SAS, and BDI have an overlapping profile concerning the total sample, except regarding age, since clinically depressed subjects have a higher mean age. Married women or living in unmarried unions, aged between 30 and 45 years, employed, carriers, and having performed the PST test for 6-7 years are a group raising higher concern and requiring a more active role with respect to the psychological impact of the PST for FAP. The role of the clinical and health psychologist with these patients is critical in the adjustment to the presymptomatic test result as well as in adherence to the available treatments conducive to a better quality of life, in carriers.Este estudio aborda el perfil de sujetos en riesgo cuyo impacto psicológico a largo plazo de las pruebas presintomáticas (PST) para la polineuropatía amiloide familiar (FAP) TTR V30M es negativo. La muestra consistió en 177 sujetos mayores de 20 años que tenían un 50% de riesgo de FAP, que habían realizado el PST hacía al menos tres años. Se contactó con los participantes por correo, solo una vez, para responder el cuestionario sociodemográfico y el Inventario de síntomas breves (BSI), la Escala de ansiedad de autoclasificación de Zung (SAS) y el Inventario de depresión de Beck (BDI). El 22.6% (BSI), el 16.4% (SAS) y el 9% (BDI) de los sujetos de la muestra presentaron un impacto psicológico negativo después de haber realizado el PST durante más de 3 años. Los sujetos con valores clínicamente significativos en BSI, SAS y BDI tienen un perfil superpuesto con respecto a la muestra total, excepto con respecto a la edad, ya que los sujetos clínicamente deprimidos tienen una edad media más alta. Las mujeres casadas o que viven en pareja, con edades entre 30 y 45 años, que trabajan, son portadoras y han realizado la prueba PST durante 6-7 años son un grupo que suscita una mayor preocupación y requiere un papel más activo con respecto al impacto psicológico del PST para FAP. El papel del psicólogo clínico y de la salud con estos pacientes es decisivo en el ajuste del resultado de la prueba presintomática, así como en la adhesión a los tratamientos disponibles que conducen a una mejor calidad de vida en los portadores.info:eu-repo/semantics/publishedVersio
    corecore