Multi-loop Control Systems of Compensators for Powerful Sounding Pulses Generators

Construction principles of multi-loop control systems of compensators for powerful sounding pulses generators are presented. A method for controlling a compensating system using fuzzy logic and forecast control ideas is described. Proposed compensating system is able to solve different problems: reactive power compensation, harmonic elimination. The system is based on a combination of a thyristor compensator and an active power filter. Some practical results with Matlab-Simulink are presented to check the proposed control performance

La irrupción de VOX en el Parlamento Español: estrategias y oposición parlamentaria

Treballs finals del Màster en Análisi Política i Assessoria Institucional, Facultat de Dret, Universitat de Barcelona. Curs: 2020-2021. Tutor: Palau Roqué, Anna M

Phase-Field Study of the History-Effect of Remelted Microstructures on Nucleation During Additive Manufacturing of Ni-Based Superalloys

In the current work we employ multi-phase-field simulations to understand the effect of remelting on microstructure evolution, especially on nucleation of new grains during selective electron beam melting (SEBM) of Ni-based super alloy. The phase-field model is coupled to both mass and heat transport phenomena including release of latent heat of solidification. We run remelting simulations in both as cast and homogenized conditions. Experimental observations show that remelting triggers the nucleation of new grains at the melt pool border. The simulation results shed more light on the local conditions at the melt pool border thereby enhancing our understanding of the mechanisms responsible for the nucleation. The simulation results are validated with experimental results obtained for the Ni–20.5 mol pct Al model binary alloy.Open Access funding enabled and organized by Projekt DEAL.Ruhr-Universität Bochum (1007

Dez anos de pesquisa científica em controladoria no Brasil (1997 – 2006)

Mudanças havidas no Brasil nas últimas décadas motivaram a demanda por profissionais contábeis mais aptos a aplicarem seus conhecimentos nas organizações. Isso estimulou o aumento, a partir de 1998, do número de programas stricto sensu em Ciências Contábeis, com áreas de concentração e/ou linhas de pesquisa em Controladoria, palco da produção científica sobre a temática. Este trabalho buscou responder a indagação sobre quais foram as características da produção científica brasileira de artigos de Controladoria entre 1997 e 2006 e buscou identificar, descrever e analisar tais características. A pesquisa é bibliométrica e descritiva, com uma abordagem quantitativa do problema. Foram analisados 154 artigos, publicados em 24 revistas Qualis A e B Nacional na área contábil. A produção sobre “Controladoria” no período foi de 4,43% dos artigos publicados. A aplicação da Lei de Bradford identificou os três núcleos de publicações sobre o assunto, com 2, 4 e 18 revistas, respectivamente. As Leis de Lotka e Pareto indicaram os autores mais produtivos revelando que ainda não há uma elite de pesquisadores sobre a temática, pois o conhecimento está disperso entre vários autores com baixa produtividade. Verificou-se que mais de 80% dos artigos analisados provêm de programas stricto sensu e, dos autores alunos de programas, 94,2% eram de Ciências Contábeis, Administração e Engenharia.In the last decades in Brazil, changes have that motivated the demand for accounting professionals capable to apply their knowledge inside the organizations. This contributed to the growth of the number of Masters and Doctoral degree programs in Accountancy since 1998 which concentrate on Controllership (in other countries Management Accounting). These programs are the scenery of the scientific production for papers on this thematic. This research intends to describe some characteristics of the scientific production in Controllership (in other countries Management Accounting) between 1997 and 2006. It´s a bibliometrical and descriptive research, with a quantitative approach of the problem. The analysis was accomplished in a sample of 154 articles published in 24 Brazilian journals with Qualis notes National A and B in the accounting areas. The production of articles on the thematic represented in the analyzed period, 4,43% of the works published in the researched journals. The application of the Bradford´s Law identified the three cores of periodicals to the publications on the thematic, 2, 4 and 18 journals respectively. The verification of the Lotka´s and Pareto´s Laws revealed that there still isn´t an elite of researchers on the thematic in Brazil, and that the knowledge is dispersed among a great number of authors with low productivity. It was revealed that more than 80% of the analyzed papers are originated in Master’s and Doctoral programs among the authors’ students of programs, 94,2% were of Accountancy, Administration and Engineering.Los cambios que se produjeron en Brasil en las últimas décadas incentivaron la demanda de profesionales contables más capacitados para aplicar sus conocimientos en las organizaciones. Esto estimuló, a partir de 1998, el aumento del número de programas stricto sensu en Ciencias Contables, con áreas de concentración y/o líneas de investigación en Contraloría, marco de la producción científica sobre la temática. Este trabajo buscó señalar cuáles fueron las características de la producción científica de artículos de Contraloría entre 1997 y 2006 y trató de identificar, describir y analizar estas características. La investigación es bibliométrica y descriptiva, con un enfoque cuantitativo del problema. Se analizaron 154 artículos, publicados en 24 revistas Qualis A y B Nacional en el área contable. La producción sobre "Contraloría" en el período fue del 4,43% de los artículos publicados. La aplicación de la Ley de Bradford identificó los tres núcleos de publicaciones sobre el asunto, con 2, 4 y 18 revistas, respectivamente. Las Leyes de Lotka y Pareto indicaron los autores más productivos y revelaron que aún no hay una élite de investigadores sobre esta temática, pues el conocimiento está disperso entre diversos autores con baja productividad. Se comprobó que más del 80% de los artículos analizados proviene de programas stricto sensu y que el 94,2% de los autores alumnos de programas, eran de Ciencias Contables, Administración e Ingeniería

Problemática de nitratos en el agua subterránea de zonas urbanas: caso de estudio Pergamino - Argentina

Un manejo sostenible del agua subterránea en zonas urbanizadas exige el conocimiento del origen y variaciones espacio-temporales de posibles contaminantes. La afectación por nitratos en Pergamino (provincia de Buenos Aires) es el principal problema de abastecimiento de agua potable para la población. Con base en la caracterización hidrogeológica del acuífero pampeano y la red de flujo asociada a la explotación del agua subterránea se analizan las condiciones hidroquímicas en la zona urbana. Asimismo, se reconoce una variación espacial en el contenido de nitratos con valores superiores a 150 mg/l en coincidencia con el cono de depresión de la zona de explotación e inferiores a 45 mg/l en la periferia. Complementariamente, las variaciones temporales en el periodo 2006- 2018 evidencian un incremento progresivo de las concentraciones en la mayoría de los pozos analizados y, en casos puntuales, oscilaciones vinculadas a variaciones estacionales. En conclusión, la fuente de contaminación se asocia a un sistema de saneamiento inadecuado y/o pérdidas en la actual red de cloacas. El deterioro en la calidad química del agua en el centro de la ciudad condujo a la inhabilitación de pozos y a la búsqueda de mejores condiciones en los sectores periurbanos.Sustainable groundwater management in urban areas requires knowledge of the spatial and temporal variations of possible contaminants. The main problem in the provision of drinking water in Pergamino (Buenos Aires) is the nitrates contamination. Based on the hydrogeological characterization of the Pampeano aquifer and the exploitation groundwater level-monitoring network, hydrochemical conditions in the urban area are analyzed. Areal variation in the nitrate content is recognized with values greater than 150 mg/l in coincidence with the cone of depression in the area of exploitation, and less than 45 mg/l in the periphery. In addition, temporal variations are observed between 2006 and 2018 with a progressive increment in concentrations in most of the wells. In some specific wells, oscillations linked to seasonal variations are observed too. In conclusion, the source of contamination is associated with an inadequate sanitation system or losses in the current sewer network. Water chemical deterioration in the center of the city led to put wells out of service and search for better conditions in the periurban sectors.Fil: Perdomo, Santiago. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Ruiz, María Soledad. Universidad Nacional del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Wahlmann, Agustina. Universidad Nacional de La Plata; ArgentinaFil: Ainchil, Jeronimo Enrique. Universidad Nacional del Noroeste de la Provincia de Buenos Aires; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Kruse, Eduardo Emilio. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; Argentin

Relevamiento y diagnóstico preliminar del servicio de provisión de agua en cooperativas de la provincia de Buenos Aires

Las cooperativas constituyen un actor clave en el suministro de agua potable en la provincia de Buenos Aires, provista fundamentalmente a partir de agua subterránea. En algunos sectores, este servicio público presenta falencias por problemas de escasa cobertura y falta de mantenimiento de la infraestructura básica. Además, dependiendo de la región, surgen necesidades relacionadas al crecimiento poblacional, a una mayor demanda y a la búsqueda de nuevas fuentes de agua. El objetivo del trabajo fue realizar un diagnóstico preliminar de la situación actual del servicio de provisión de agua potable brindado por cooperativas de la provincia a través de un relevamiento e inventario de datos técnicos. En la provincia existen 157 cooperativas que proveen de agua a población, de las cuales se seleccionaron y visitaron 50 localidades sobre las que se realizó una entrevista de las características del abastecimiento de agua, incluyendo aspectos de la fuente, infraestructura, operación, mantenimiento, calidad del agua y saneamiento. A partir del análisis de los registros recopilados se pudieron identificar los principales puntos que afectan la calidad y la sustentabilidad ambiental del servicio. La base de datos generada reviste importancia a nivel regional y posibilita la generación y aplicación de medidas preventivas y correctivas que podrían ser adaptadas a diferentes situaciones, con la finalidad de optimizar la gestión del recurso hídrico y el abastecimiento de agua.Cooperatives in the province of Buenos Aires are a key stakeholder in the supply of drinking water produced mainly from groundwater exploitation. In some sectors, this public service has deficiencies related to population growth, increased demand and the search for new water sources. The objective of this work was to survey and inventory the available data to produce a preliminary diagnosis of the present situation of the water supply service provided by 157 cooperatives in the province. Fifty of them were selected and interviewed about the characteristics of the water supply including aspects regarding source, infrastructure, operation, maintenance, water quality and sanitation. The data analysis allowed to identify the main critical aspects affecting the quality and environmental sustainability of the service. The database created becomes important at the regional level since it enables the application of preventive and corrective measures that could be adapted to the situation of different localities to optimize the water management and supply service.Centro de Estudios Integrales de la Dinámica Exógen

Experimental Validation of Property Models and Databases for Computational Superalloy Design

Computational superalloy development is a powerful alternative to the conventional experimental approach. Based on thermodynamic databases and the CALPHAD method, it is possible to estimate the properties of a large number of potential alloys and select the most promising ones. However, the accuracy of the databases and complementary property models can be unsatisfying. The accuracy of two mass density and γ/γ′\gamma / \left(\gamma\right)^{&aposx;}lattice parameter models and the TTNI8 and TCNI10 databases is analyzed in detail on the experimental basis of computationally optimized single‐crystalline superalloys. Various properties are measured and compared to the results of the property models and databases. Neither of the databases is superior to the other and especially the γ′\left(\gamma\right)^{&aposx;}solvus temperature is not accurately described in both. The new mass density model, a linear regression based on the molar mass, is more reliable for low‐density alloys. Both lattice parameter model versions slightly overestimate the room‐temperature γ$$\gamma$$ lattice parameter. The γ′\left(\gamma\right)^{&aposx;}lattice parameter, however, is more accurately calculated using the new model version. The results of this study can be readily used to improve a multicriteria alloy optimization tool for computational superalloy design.The backbone of computational alloy design are thermodynamic databases for the CALPHAD method and property models. The accuracy of two databases and model versions for the mass density and the γ/γ′\gamma / \left(\gamma\right)^{&aposx;}lattice misfit are evaluated. The experimental subject of this study are computationally optimized Ni‐based superalloys. This provides insight into the model and database performance in the unknown composition spaces. image © 2024 WILEY‐VCH GmbHDeutsche Forschungsgemeinschaft DF

Using Selective Electron Beam Melting to Enhance the High‐Temperature Strength and Creep Resistance of NiAl–28Cr–6Mo In Situ Composites

By increasing the density of interfaces in NiAl–CrMo in situ composites, the mechanical properties can be significantly improved compared to conventionally cast material. The refined microstructure is achieved by manufacturing through electron beam powder bed fusion (PBF‐EB). By varying the process parameters, an equiaxed or columnar cell morphology can be obtained, exhibiting a plate‐like or an interconnected network of the (Cr,Mo) reinforcement phase which is embedded in a NiAl matrix. The microstructure of the different cell morphologies is investigated in detail using scanning electron microscope, transmission electron microscopy, and atom probe tomography. For both morphologies, the mechanical properties at elevated temperatures are analyzed by compression and creep experiments parallel and perpendicular to the building direction. In comparison to cast NiAl and NiAl–(Cr, Mo), the yield strength of the PBF‐EB fabricated specimens is significantly improved at temperatures up to 1,027 °C. While the columnar morphology exhibits the best improved mechanical properties at high temperatures, the equiaxial morphology shows nearly ideal isotropic mechanical behavior, which is a substantial advantage over directionally solidified material.The additive manufacturing of NiAl–28Cr–6Mo in situ composites improves the mechanical properties significantly compared to conventionally cast material. By varying the process parameters, an equiaxed or columnar cell morphology can be obtained, exhibiting a plate‐like or an interconnected network of the (Cr,Mo) reinforcement phase. The yield strength of the PBF‐EB fabricated specimens is significantly improved at temperatures up to 1027 °C. image © 2023 WILEY‐VCH GmbH Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165

Influence of the W and Ta content on the High-Temperature Oxidation Resistance of Multinary Co/Ni-Based Superalloys at 1050 °C and 1150 °C

Outstanding inherent environmental resistance is a precondition for the use of superalloys in high-temperature applications. Besides high Al and Cr levels, also refractory metal concentrations (W and Ta) are reported to affect protective scale formation, as these elements are expected to affect the chemical activity and also the transport of protective scale formers within the alloy. In this study, we elucidate the high-temperature oxidation behavior of 3 Co-based (Co/Ni ratio: 1.4) and 3 Ni-based (Co/Ni ratio: 0.7) superalloys differing in W and Ta levels. Time-resolved thermogravimetric analysis (TGA) in synthetic air at 1050 °C and 1150 °C for 100 h, scanning electron microscopy analysis (SEM), thermodynamic calculations using the CALPHAD software Thermo-Calc, and diffusion couple experiments were conducted to assess the impact of the Co/Ni ratio and the refractory metal content on the oxidation performance. The results indicate that a low W content (3 vs. 5 at.%) and a high Ta content (2.1 vs. 1.5 at.%) beneficially affect the oxidation resistance, as alumina scale formation is facilitated.Open Access funding enabled and organized by Projekt DEAL.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659EAM-SG21-3Friedrich-Alexander-Universität Erlangen-Nürnberg (1041