Valorization of brines in the chlor-alkali industry. Integration of precipitation and membrane processes

Reuse of brines in the chlor-alkali industry can be benefitial both in terms of new material source for the industry and environmental impact reduction of the brines disposal. In this thesis, reuse of Seawater Reverse Osmosis Desalination brine as well as potash mine brine is studied. Seawater Reverse Osmosis from the El Prat Desalination Plant and potash mine brine from the Llobregat brine collector pipe were used for this study. These kinds of brines were chemically characterized using different analytical methods that had to be adapted to the hiigh saliniities of the samples. According to the composition results obtained and the literature reviewed, several treatments were evaluated to reach the membrane electrolysis process requirements of the chlor-alkali industry. Potash mine brine had high sodium chloride concentration and in consequence, only purification was studied. Electrodialysis, nanofiltration and precipitation were studied for brines concentration and primary purification. Experiments in the laboratory and in pilot plants were carried out. Pilot plants were designed and operated to determine the optimal conditions to treat the brines and design a feasible system to valorize the brines in the chlor-alkali industry using membrane electrolysis cells. Electrodialysis was demonstrated a feasible technology for SWD-RO brine concentration, as it concentrated the brine and at the same time produced some useful by-products that could be further valorized. Performance obtained was highly dependent on inlet temperature ! and current densities used. The optimal ED operation point was determined when working in a continuous mode at 0.5kA/m2 were 18L/h of 244 g/L NaCl with 0.16 kWh/kg NaCl energy consumption were obtained. A first purification of polyvalent ions was reached using ED. Nanofiltration efficiently removed polyvalent ions from both brines studied. The optimal operation point was around 20 bar in both cases. In the pilot plant, pressures higher than 20bar could not be evaluated due to fixed inlet flow. Removal of sulphates, calcium and magnesium was higher than 90%, 50% and 70% in both brines studied whereas NaCl was only removed by 12% maximum at 20bar, which was benefitial for its reuse. Removal of minor elements was also studied and depended on ionic radii as well as ionic charge. Precipitation using NaOH and Na2CO3 reagents was evaluated to remove calcium and magnesium from the brines at different inlet temperatures. Temperatures over 65ºC increased calcium purification per! formance, especially on SWD-RO brines which contained all the ! antiscala! nts of the RO process that avoided calcium carbonate and sulphate precipitation. In consequence, the amount of reactants needed to reach the optimal purification point was higher than the values reported in the literature. Nevertheless, purifications efficiencies higher than 95% could be obtained. Reactant order addition effect on the purification performance results obtained was not considered significant Precipitates obtained during the purification process could be further valorized.Integration of membrane and precipitation process was needed in order to efficiently treat the brines studied. Finally, a mathematical model to predict the concentration performance and design future experiments was developed and validated with the results obtained in the pilot plant

Reducing the fine-tuning of gauge-mediated SUSY breaking

Despite their appealing features, models with gauge-mediated supersymmetry breaking (GMSB) typically present a high degree of fine-tuning, due to the initial absence of the top trilinear scalar couplings, $A_t=0$. In this paper, we carefully evaluate such a tuning, showing that is worse than per mil in the minimal model. Then, we examine some existing proposals to generate $A_t\neq 0$ term in this context. We find that, although the stops can be made lighter, usually the tuning does not improve (it may be even worse), with some exceptions, which involve the generation of $A_t$ at one loop or tree level. We examine both possibilities and propose a conceptually simplified version of the latter; which is arguably the optimum GMSB setup (with minimal matter content), concerning the fine-tuning issue. The resulting fine-tuning is better than one per mil, still severe but similar to other minimal supersymmetric standard model constructions. We also explore the so-called "little $A_t^2/m^2$ problem", i.e. the fact that a large $A_t$-term is normally accompanied by a similar or larger sfermion mass, which typically implies an increase in the fine-tuning. Finally, we find the version of GMSB for which this ratio is optimized, which, nevertheless, does not minimize the fine-tuning.Comment: 16 pages, 11 figures, 1 appendix. Discussion extended, matches EPJC published versio

On bulk-synchronous distributed-memory parallel processing of relational-database transactions

This paper describes two parallel algorithms for the eÆcient processing of relational database transactions and presents a performance analysis of them. These algorithms are built upon the bulk-synchronous parallel model of computation. The well-de ned structure of this model enabled us to evaluate their performance by using an implementation independent and yet em- pirical approach which includes the e ects of synchronization, communication and computation. The analysis reveals that the algorithm which borrows ideas from optimistic parallel discrete event simulation achieves better performance than the classical approach for synchronizing con- current transactions on a distributed memory system.Eje: Programación concurrenteRed de Universidades con Carreras en Informática (RedUNCI

What is a Natural SUSY scenario?

The idea of "Natural SUSY", understood as a supersymmetric scenario where the fine-tuning is as mild as possible, is a reasonable guide to explore supersymmetric phenomenology. In this paper, we re-examine this issue in the context of the MSSM including several improvements, such as the mixing of the fine-tuning conditions for different soft terms and the presence of potential extra fine-tunings that must be combined with the electroweak one. We give tables and plots that allow to easily evaluate the fine-tuning and the corresponding naturalness bounds for any theoretical model defined at any high-energy (HE) scale. Then, we analyze in detail the complete fine-tuning bounds for the unconstrained MSSM, defined at any HE scale. We show that Natural SUSY does not demand light stops. Actually, an average stop mass below 800 GeV is disfavored, though one of the stops might be very light. Regarding phenomenology, the most stringent upper bound from naturalness is the one on the gluino mass, which typically sets the present level of fine-tuning at ${\cal O}(1\%)$. However, this result presents a strong dependence on the HE scale. E.g. if the latter is $10^7$ GeV the level of fine-tuning is $\sim$ four times less severe. Finally, the most robust result of Natural SUSY is by far that Higgsinos should be rather light, certainly below 700 GeV for a fine-tuning of ${\cal O}(1\%)$ or milder. Incidentally, this upper bound is not far from $\simeq1$ TeV, which is the value required if dark matter is made of Higgsinos.Comment: 41 pages, 8 figures, 9 tables. References added, matches JHEP published versio

Naturalness of MSSM dark matter

There exists a vast literature examining the electroweak (EW) fine-tuning problem in supersymmetric scenarios, but little concerned with the dark matter (DM) one, which should be combined with the former. In this paper, we study this problem in an, as much as possible, exhaustive and rigorous way. We have considered the MSSM framework, assuming that the LSP is the lightest neutralino, $\chi_1^0$, and exploring the various possibilities for the mass and composition of $\chi_1^0$, as well as different mechanisms for annihilation of the DM particles in the early Universe (well-tempered neutralinos, funnels and co-annihilation scenarios). We also present a discussion about the statistical meaning of the fine-tuning and how it should be computed for the DM abundance, and combined with the EW fine-tuning. The results are very robust and model-independent and favour some scenarios (like the h-funnel when $M_{\chi_1^0}$ is not too close to $m_h/2$) with respect to others (such as the pure wino case). These features should be taken into account when one explores "natural SUSY" scenarios and their possible signatures at the LHC and in DM detection experiments.Comment: 28 pages, 18 figures. References added, matches JHEP published versio

Evaluación de alternativas de financiamiento para implementar una planta procesadora de biodiésel a partir de aceites usados y grasa animal, en la provincia de Chiclayo 2017

La presente investigación da a conocer el biodiésel como un combustible renovable proveniente de aceites vegetales de cocina usados o grasas de origen animal, en las que se pueden utilizar de forma total o parcial, cumpliendo la función de reemplazar el combustible diésel de los motores sin requerir una modificación de estos. Es por este el motivo que se realizó un estudio de viabilidades comprendido en: Estudio de mercado enfocado en la posición del proyecto en el mercado, y establecer un predio de referencia. Estudio de la producción potencial de aceites usados, comprendiendo alianzas estratégicas para la recolección de los aceites usados de cocina como materia prima del biodiésel. Se realizó un estudio técnico, en las cuales se da a conocer las características del proceso productivo y bajo que paramentos se producirá el biocombustible. Posteriormente se realizó un estudio de localización, para determinar geográficamente donde estará ubicada la planta procesadora de biodiésel. Por último, se pasó a realizar un estudio económico-financiero, basado en la evaluación de alternativas de financiamiento, para un leasing financiero, siendo el más rentable la tasa financiera brindada por la entidad financiera BCP – Banco Crédito del Perú. En la etapa de evaluación se buscara determinar la viabilidad del proyecto, a partir de lo estudiado anteriormente, donde se medirán los resultados de someter el proyecto a variaciones en algunos de sus parámetros más importantes. Obteniendo resultados positivos tanto en VAN Y TIR, haciéndolo al proyecto viable y muy atractivo en cuanto a inversión

Integration of monopolar and bipolar electrodialysis for valorization of seawater reverse osmosis desalination brines: Production of strong acid and base

Water scarcity in the Mediterranean basin has been solved by using seawater desalination reverse osmosis technology (SWD-RO). This technology produces brine which is discharged back into the sea resulting in an environmental impact on marine ecosystems. Under the circular economy approach, the aim of this work is to recover resources from NaCl-rich brine (~60-70 g/L), e.g. in the form of NaOH and HCl, by integration of two ion exchange-based membrane technologies and quantify the electrical energy consumption. Electrodialysis (ED) incorporating monovalent selective cation exchange membranes as divalent ions purification and concentration of the NaCl present in the SWD-RO brine, was integrated with bipolar membrane ED (EDBM) to produce NaOH and HCl. Current densities of 0.30–0.40 kA/m2 at two temperature ranges simulating different seawater temperature regimes (15-18 ºC and 22-28ºC) were tested and a pure NaCl solution was used as starting concentrate stream. NaCl-rich brines with 100 or 200 gNaCl/L were obtained by ED and then introduced in the EDBM stack producing HCl and NaOH up to 2 M, depending on the initial concentrations. A minimum energy consumption of 1.7 kWh/kgNaOH was calculated when working by EDBM with initial concentrations of 104 g NaCl/L and 0.24 M HCl and NaOH.Peer ReviewedPostprint (author's final draft

Bases para implantar un programa de salud podológica en triatletas

Objetivos: Crear las bases para implantar un Programa de Salud podológica en triatletas mediante la determinación de las lesiones podológicas más frecuentes y los factores de riesgo y/o predisponentes en triatletas y comprobar el grado de información y los hábitos en los autocuidados del pie del triatleta. Método: los datos de este trabajo se extrajeron de un estudio observacional, descriptivo, transversal y retrospectivo. Se ha recogido información sobre las características personales, el nivel de entrenamiento y competición, las lesiones podológicas más frecuentes, los factores de riesgo, los hábitos en los autocuidados del pie de los triatletas y la participación del podólogo. Para cumplir los objetivos planteados se diseñó una herramienta exclusiva tratándose de un cuestionario cumplimentado por los triatletas a través de la aplicación Google Drive. Resultados: La muestra está compuesta por 468 triatletas, 422 hombres y 46 mujeres de edades comprendidas entre 13 y los 59 años. Las lesiones podológicas más frecuentes, una vez finalizada la prueba, han sido: ampollas en el pulpejo de los dedos y hematomas subungueales. La mayoría de las lesiones han ocurrido durante la carrera. El 81% de los triatletas sufren lesiones con frecuencia, tratándose principalmente de sobrecargas musculares de los gemelos. Uno de cada dos triatletas ha recibido información sobre cómo cuidarse los pies. Uno de cada dos triatletas ha acudido alguna vez al podólogo. Los triatletas que más usan calcetines en competición son los que participan en pruebas de media distancia y los que menos lo usan son los que participan en distancia sprint, los triatletas que menos usan vaselina son los que participan en distancia super sprint y los que más la usan son los participantes en la distancia iron man. Conclusiones: la presencia de lesiones podológicas y la falta de conocimiento sobre cómo cuidarse los pies justifica la importancia de crear un Programa de Salud podológica en triatletas. Los resultados de esta investigación podrán ser útiles para planificar e implementar futuras intervenciones educativas y para que sean más efectivas.Objectives: To create the basis for implementing a health podiatric program for triathletes by determining the most frequent injuries and risk factors and / or predisposing factors in triathletes and to verify the degree of information and habits in the self-care of triathlete's feet. Method: Data from this study was extracted from an observational, descriptive, cross - sectional and retrospective study. Information on personal characteristics, level of training and competition, most frequent injuries, risk factors, self-care of the triathletes' feet and participation of the podiatrist have been collected. In order to meet the objectives set an exclusive tool was designed in the form of a questionnaire completed by triathletes through the Google Drive application. Results: The sample is made up of 468 triathletes, 422 men and 46 women between the ages of 13 and 59. The most frequent injuries, once the race was completed, were: blisters on the fingertip and subungual hematomas. Most injuries occurred during the race. 81% of triathletes suffer injuries frequently, mainly involving muscle overload of the twins. One in two triathletes has received information about taking care of their feet. One in every two triathletes has visited a podiatrist. The triathletes who wear socks most frequently in competition are those who participate in races of medium distance and those who wear them the least are those who participate in races of sprinting distance. The triathletes who use Vaseline the least are those who participate in races of Super sprint distance whilst those who use it the most are participants in the Iron Man distance. Conclusions: the existence of podological injuries and lack of knowledge about how to take care of feet highlights the importance of creating a Podiatry Health Program for triathletes. The results of this research could provide useful assistance in planning and implementing future educational interventions and ensuring they are more effective

Uso del material informático como herramienta didáctica para el aprendizaje de las Matemáticas

Este trabajo trata sobre el aprendizaje de las matemáticas en Educación Infantil a través de las TIC, tomándolas como una herramienta didáctica más dentro del aula. En dicho trabajo se plantea una Propuesta Didáctica en la cual se compara el aprendizaje de las matemáticas con y sin el uso de las Nuevas Tecnologías, con el fin de observar la capacidad de los niños y niñas por aprender matemáticas tanto de una forma como de otra. Pretendemos, así mismo, conseguir mayor motivación al mismo tiempo que los niños y niñas se divierten y disfrutan de su propio aprendizaje.Grado en Educación Infanti