On track for solar grade silicon through a Siemens process-type laboratory reactor: operating conditions and energy savings

Polysilicon cost impacts significantly on the photovoltaics (PV) cost and on the energy payback time. Nowadays, the besetting production process is the so called Siemens process, polysilicon deposition by chemical vapor deposition (CVD) from Trichlorosilane. Polysilicon purification level for PV is to a certain extent less demanding that for microelectronics. At the Instituto de Energía Solar (IES) research on this subject is performed through a Siemens process-type laboratory reactor. Through the laboratory CVD prototype at the IES laboratories, valuable information about the phenomena involved in the polysilicon deposition process and the operating conditions is obtained. Polysilicon deposition by CVD is a complex process due to the big number of parameters involved. A study on the influence of temperature and inlet gas mixture composition on the polysilicon deposition growth rate, based on experimental experience, is shown. Moreover, CVD process accounts for the largest contribution to the energy consumption of the polysilicon production. In addition, radiation phenomenon is the major responsible for low energetic efficiency of the whole process. This work presents a model of radiation heat loss, and the theoretical calculations are confirmed experimentally through a prototype reactor at our disposal, yielding a valuable know-how for energy consumption reduction at industrial Siemens reactorsPostprint (published version

Comparación entre pacientes hipertensos con infarto cerebral lagunar y hemorragia intracerebral profunda primaria

It was carried out a descriptive and prospective study of the hypertensive patients with diagnostic of lacunar cerebral infarct or deep primary intracerebral hemorrhages in acute phase who were assisted in the intermediate care Unit and in the neurology Service of the Provincial University Hospital Arnaldo Milián Castro during the period among July 1 2000 to June 30 2001. We intended to compare the factors of cerebrovascular risk, the localization of the lesions and the prognosis among hypertensive patients with lacunar cerebral infarct and deep primary intracerebral hemorrhages, and the relationship of these factors in the functional state at the time of remission and in the mortality. For the statistical analysis it was created a database of the results obtained in the pattern of collection of data and later it was used Windows SPSS program. We find that the lacunar cerebral infarct and deep primary intracerebral hemorrhages have the same localization in deep areas of the brain, the affectation of same arteries, and also that the main factor of risk is the arterial hypertension. Besides the fundamental difference (isquemia versus hemorrhage) there are other differences in the behaviour of the factors of risk, in the specific localization of the lesion and in the prognosis at the time of remission. These findings made us consider that the differences in certain factors of risk and in specific localization of the lesions can be the key to explain the outcome of the ischemic and hemorrhagic lesion of the small cerebral arteries.Se realizó un estudio descriptivo y prospectivo de los pacientes hipertensos con diagnóstico de infarto cerebral lacunar o de hemorragia profunda primaria en fase aguda que fueron atendidos en la Unidad de Cuidados Intermedios y en el Servicio de Neurología del Hospital Provincial Universitario Arnaldo Milián Castro durante el período comprendido entre el 1 de julio de 2000 hasta el 30 de junio de 2001. Nos propusimos comparar los factores de riesgo cerebrovascular, la localización de las lesiones y el pronóstico entre pacientes hipertensos con infarto cerebral lacunar y con hemorragia intracerebral profunda primaria, y la relación de estos factores en la situación funcional al egreso y en la mortalidad. Para el análisis estadístico se creó una base de datos a partir de los resultados obtenidos en el modelo de recogida de datos y posteriormente se utilizó el programa SPSS para Windows. Encontramos que el infarto cerebral lacunar y la hemorragia intracerebral profunda primaria tienen en común la localización en áreas profundas del cerebro, la afectación de las mismas arterias y la hipertensión arterial como principal factor de riesgo, y que poseen además de la diferencia fundamental, isquemia versus hemorragia, otras diferencias en cuanto al comportamiento de los factores de riesgo, la localización específica de la lesión y el pronóstico al egreso. Estos hallazgos nos hicieron considerar que las diferencias en cuanto a determinados factores de riesgo y a la localización específica de las lesiones pueden ser la clave para explicar el desenlace de la enfermedad isquémica y hemorrágica de las pequeñas arterias cerebrales

Positioning system for 3D scans inside objects

En este trabajo presentamos un sistema de posicionamiento de visión activa para el escaneo 3D del interior de piezas. El diseño del sistema propuesto consta de dos módulos: un sistema de dimensionamiento 2D de visión activa, y un sistema que posiciona el módulo de visión activa. El sistema de posicionamiento es capaz de determinar la profundidad del sistema de dimensionamiento 2D de visión activa en el interior del objeto a escanear usando varios sensores. Las principales contribuciones de este trabajo son la caracterización del sistema de dimensionamiento 2D, y el desarrollo de algoritmos de posicionamiento de la luz activa con énfasis en el modelado y fusión de sensores. El sistema puede utilizarse como un sistema de dimensionamiento en aplicaciones industriales como la industria metal mecánica, la aeronáutica, la medicina, en el control de calidad y en áreas de visión por computadora.In this work we present an active positioning system for 3D scan of interior parts. The design of the proposed system consists of two modules: an active 2D dimensional system and positional system based on active vision. The active 2D dimensional system is able to determine the depth of the 2D dimensional system inside the object to be scanned using several sensors. The main contributions of this work are the characterization of the 2D dimensional system and the development of active light positioning algorithms with emphasis on the modeling and fusion of the sensors. The system can be used as a dimensional system in industrial applications such as the metal mechanical industry, aeronautics industry, medicine, quality control and computer vision.Peer Reviewe

On track for solar grade silicon through a siemens process-type laboratory reactor: operating conditions and energy savings

Polysilicon cost impacts significantly on the photovoltaics (PV) cost and on the energy payback time. Nowadays, the besetting production process is the so called Siemens process, polysilicon deposition by chemical vapor deposition (CVD) from Trichlorosilane. Polysilicon purification level for PV is to a certain extent less demanding that for microelectronics. At the Instituto de Energía Solar (IES) research on this subject is performed through a Siemens process-type laboratory reactor. Through the laboratory CVD prototype at the IES laboratories, valuable information about the phenomena involved in the polysilicon deposition process and the operating conditions is obtained. Polysilicon deposition by CVD is a complex process due to the big number of parameters involved. A study on the influence of temperature and inlet gas mixture composition on the polysilicon deposition growth rate, based on experimental experience, is shown. Moreover, CVD process accounts for the largest contribution to the energy consumption of the polysilicon production. In addition, radiation phenomenon is the major responsible for low energetic efficiency of the whole process. This work presents a model of radiation heat loss, and the theoretical calculations are confirmed experimentally through a prototype reactor at our disposal, yielding a valuable know-how for energy consumption reduction at industrial Siemens reactors

Heat losses in a CVD reactor for polysilicon: comprehensive model and experimental validation

This work addresses heat losses in a CVD reactor for polysilicon production. Contributions to the energy consumption of the so-called Siemens process are evaluated, and a comprehensive model for heat loss is presented. A previously-developed model for radiative heat loss is combined with conductive heat loss theory and a new model for convective heat loss. Theoretical calculations are developed and theoretical energy consumption of the polysilicon deposition process is obtained. The model is validated by comparison with experimental results obtained using a laboratory-scale CVD reactor. Finally, the model is used to calculate heat consumption in a 36-rod industrial reactor; the energy consumption due to convective heat loss per kilogram of polysilicon produced is calculated to be 22-30 kWh/kg along a deposition process

Conceptual design of the ITER fast-ion loss detector

A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ∼5 ◦ might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ∼11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.Marie Curie FP7 Integration PCIG11-GA2012-321455Ministerio de Economía y Competitividad RYC-2011-09152, FIS2015-69362-P, ENE2012- 3108

Smart feeding in farming through IoT in silos

Smart farming practices are of utmost importance for any economy to foster its growth and development and tackle problems like hunger and food insecurity and ensure the well-being of its citizens. However, such practices usually require large investments that are not affordable for SMEs. Such is the case of expensive weighing machines for silos, while the range of possibilities of the Internet of Things (IoT) could intensively reduce these costs while connecting the data to intelligent Cloud services, such as smart feeding systems. The paper presents a novel IoT device and methodology to monitor quantity and quality of grains in silo by estimating the volume of grains at different time instants along with temperature and humidity in the silo. A smart feeding system, implemented via a virtual organization of agents, processes the data and regulates the grain provided to the animals. Experimental on-field measurements at a rabbit farm show the suitability of the proposed system to reduce waste as well as animal diseases and mortality

Convertidores de potencia para microrredes y sistemas de generación distribuidos

This paper presents an overview and critical discussion about the utilization of power converters in several microgrid configurations that incorporate non-conventional renewable energy sources and energy storage. The methodology is developed over 69 works published in this research topic. The papers are selected from databases in electrical engineering, e.g., IEEExplore, ScienceDirect, Springer, MDPI, etc. Then, the papers are classified depending on its focus, i.e., power converters in microgrids or power converters in distribution systems. At least, three classifications are proposed and one of them is made over more than 40 papers about power converters used in microgrids and electric distribution systems. Given the wide variety of microgrids and their configurations, the selection of appropriate power converters for every scenario is not trivial; therefore, this work also classifies the converters in their most common application, their advantages and disadvantages, and also point out the study domain, i.e., simulation or physical implementation. One of the main conclusions made from the overview is a gap identified in the study of direct current/ direct current microgrids despite being the simplest configuration among the three analyzed configurations. This is because hybrid and alternate current microgrids are more widely used since they allow taking advantage of the infrastructure of the current electrical systems.Este artículo presenta una visión general y una discusión crítica sobre la utilización de convertidores de potencia en varias configuraciones de microrredes que incorporan fuentes de energía renovable no convencionales y almacenamiento de energía. La metodología se desarrolla sobre 69 trabajos publicados en este tema de investigación. Los documentos se seleccionan de bases de datos en ingeniería eléctrica, p. ej. IEEExplore, ScienceDirect, Springer, MDPI, etc. Luego, los artículos se clasifican según su enfoque, es decir, convertidores de potencia en microrredes o convertidores de potencia en sistemas de distribución. Se proponen al menos tres clasificaciones y una de ellas se realiza sobre más de 40 artículos sobre convertidores de potencia utilizados en microrredes y sistemas de distribución eléctrica. Dada la gran variedad de microrredes y sus configuraciones, la selección de convertidores de potencia apropiados para cada escenario no es trivial; por lo tanto, este trabajo también clasifica a los convertidores en su aplicación más común, sus ventajas y desventajas, y también señala el dominio de estudio, es decir, simulación o implementación física. Una de las principales conclusiones extraídas de la visión general es una brecha identificada en el estudio de las microrredes de corriente continua / corriente continua a pesar de ser la configuración más simple entre las tres configuraciones analizadas. Esto se debe a que las microrredes híbridas y de corriente alterna son las más utilizadas ya que permiten aprovechar la infraestructura de los sistemas eléctricos actuales

A fast feedback controlled magnetic drive for the ASDEX Upgrade fast-ion loss detectors

A magnetically driven fast-ion loss detector system for the ASDEX Upgrade tokamak has been designed and will be presented here. The device is feedback controlled to adapt the detector head position to the heat load and physics requirements. Dynamic simulations have been performed taking into account effects such as friction, coil self-induction, and eddy currents. A real time positioning control algorithm to maximize the detector operational window has been developed. This algorithm considers dynamical behavior and mechanical resistance as well as measured and predicted thermal loads. The mechanical design and real time predictive algorithm presented here may be used for other reciprocating systems.EURATOM 63305

Current Understanding of the Physiopathology, Diagnosis and Therapeutic Approach to Alzheimer’s Disease

L.M.-R. and J.J.R.-R. are funded by P20-01293 from Junta de Andalucia, Spain. J.J.R.-R. is additionally funded by PECART-0096-2020 from Junta de Andalucia, Spain and PID2020-117544RB-100 from the Ministry of Science and Innovation, Spain.Alzheimer's disease (AD) is the most common cause of dementia. It is characterized by cognitive decline and progressive memory loss. The aim of this review was to update the state of knowledge on the pathophysiological mechanisms, diagnostic methods and therapeutic approach to AD. Currently, the amyloid cascade hypothesis remains the leading theory in the pathophysiology of AD. This hypothesis states that amyloid-beta (A beta) deposition triggers a chemical cascade of events leading to the development of AD dementia. The antemortem diagnosis of AD is still based on clinical parameters. Diagnostic procedures in AD include fluid-based biomarkers such as those present in cerebrospinal fluid and plasma or diagnostic imaging methods. Currently, the therapeutic armory available focuses on symptom control and is based on four pillars: pharmacological treatment where acetylcholinesterase inhibitors stand out; pharmacological treatment under investigation which includes drugs focused on the control of A beta pathology and tau hyperphosphorylation; treatment focusing on risk factors such as diabetes; or nonpharmacological treatments aimed at preventing development of the disease or treating symptoms through occupational therapy or psychological help. AD remains a largely unknown disease. Further research is needed to identify new biomarkers and therapies that can prevent progression of the pathology.Junta de Andalucia European Commission P20-01293 PECART-0096-2020Spanish Government European Commission PID2020-117544RB-10