Dynamic analysis of Free-Piston Stirling Engine/Linear Alternator-load system-experimentally validated

This paper discusses the effects of variations in system parameters on the dynamic behavior of the Free-Piston Stirling Engine/Linear Alternator (FPSE/LA)-load system. The mathematical formulations incorporate both the mechanical and thermodynamic properties of the FPSE, as well as the electrical equations of the connected load. A state-space technique in the frequency domain is applied to the resulting system of equations to facilitate the evaluation of parametric impacts on the system dynamic stability. Also included is a discussion on the system transient stability as affected by sudden changes in some key operating conditions. Some representative results are correlated with experimental data to verify the model and analytic formulation accuracies. Guidelines are given for ranges of the system parameters which will ensure an overall stable operation

Eficacia escolar en escuelas bilingües en Puno, Perú

Señala que algunos países han implementado programas de etnoeducación; en Perú, se presenta que la mayoría de hablantes indígenas se encuentra en la sierra. Presenta el caso de la diglosia, la lengua dominante y la experiencia con el Ministerio de Educación al gestionar un proyecto de capacitación de los hablantes bilingües en la región Sur del País. Se incluyen resultados de escuelas EBI y monolingües en español (ME) y datos acerca de la implementación de dicho programa en el departamento de Puno, Perú

Realidad educativa en los institutos superiores tecnológicos en turismo y su influencia en la actividad turística - Cusco

Publicación a texto completo no autorizada por el autorEvalúa la situación actual en que se encuentran los Institutos Superiores Tecnológicos en Turismo en la ciudad del Cusco, instituciones que en base a sus respectivas curriculas, ofrecen estudios de mando medio a todos aquellos estudiantes que en su mayor parte no logran ingresar a las universidades sean nacionales o particulares quienes al quedar postrados los obliga a tener que concurrir a estos centros de enseñanza para posibilitar una profesión de educación superior. Conforme a las investigaciones realizadas en los diferentes Institutos Superiores Tecnológicos en Turismo, se ha determinado que muchos de ellos no cumplen con lo ofrecido, que solo optan por los ingresos económicos, olvidándose de la parte académica, el cual constituye un engaño y farsa con los estudiantes que depositan su confianza. Con respecto a la presencia de los egresados en el mercado ocupacional del Cusco, de acuerdo al análisis que se tiene, se viene demostrando que no tienen mucha presencia o aceptación por parte de las entidades públicas y privadas del sector turismo y que muchos de ellos solo cumplen labores de manera eventual, mientras tanto las instituciones educativas de mando medio, solo importándoles sacar más egresados, sin medir las consecuencias y por tanto no interesándoles en los más mínimo el desarrollo de habilidades de sus profesionales egresados.Tesi

A free-piston Stirling engine/linear alternator controls and load interaction test facility

A test facility at LeRC was assembled for evaluating free-piston Stirling engine/linear alternator control options, and interaction with various electrical loads. This facility is based on a 'SPIKE' engine/alternator. The engine/alternator, a multi-purpose load system, a digital computer based load and facility control, and a data acquisition system with both steady-periodic and transient capability are described. Preliminary steady-periodic results are included for several operating modes of a digital AC parasitic load control. Preliminary results on the transient response to switching a resistive AC user load are discussed

Single Phase Passive Rectification Versus Active Rectification Applied to High Power Stirling Engines

Stirling engine converters are being considered as potential candidates for high power energy conversion systems required by future NASA explorations missions. These types of engines typically contain two major moving parts, the displacer and the piston, in which a linear alternator is attached to the piston to produce a single phase sinusoidal waveform at a specific electric frequency. Since all Stirling engines perform at low electrical frequencies (less or equal to 100 Hz), space explorations missions that will employ these engines will be required to use DC power management and distribution (PMAD) system instead of an AC PMAD system to save on space and weight. Therefore, to supply such DC power an AC to DC converter is connected to the Stirling engine. There are two types of AC to DC converters that can be employed, a passive full bridge diode rectifier and an active switching full bridge rectifier. Due to the inherent line inductance of the Stirling Engine-Linear Alternator (SE-LA), their sinusoidal voltage and current will be phase shifted producing a power factor below 1. In order to keep power the factor close to unity, both AC to DC converters topologies will implement power factor correction. This paper discusses these power factor correction methods as well as their impact on overall mass for exploration applications. Simulation results on both AC to DC converters topologies with power factor correction as a function of output power and SE-LA line inductance impedance are presented and compared

Single‐molecule enzymology à la Michaelis–Menten

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102694/1/febs12663.pd

Nanosuspensions: particle size reduction as tool to improve lipophilic drugs bioavailability

En los últimos años, las nanosuspensiones han sido objeto de numerosos estudios con el n de evaluar sus propiedades biofarmacéuticas, demostrando en muchos casos valiosas ventajas frente a las formulaciones utilizadas convencionalmente. El uso de esta novedosa tecnología ha permitido el desarrollo de formas farmacéuticas para ser administradas por diferentes vías y también su aplicación ha demostrado ventajas en el desarrollo de estudios toxicológicos. En el presente trabajo se plantea una revisión de los aportes que brinda la obtención de partículas nanométricas de principios activos a la tecnología farmacéutica, los procesos de obtención de las mismas, así como su caracterización y principales aplicaciones en diferentes vías de administración de fármacos.In recent years, nanosuspensions have been subject of numerous studies in order to evaluate their biopharmaceutical properties, demonstrating in many cases valuable advantages over the conventional formulations. The application of this innovative technology has allowed the development of pharmaceutical dosage forms designed to be administrated by di erent routes, and its application has also demonstrated some advantages in the development of toxicological studies. This paper presents a review of the contributions that nanometric particles provide to the pharmaceutical technology area, the design and formulation procedures, characterization studies and principal applications.Fil: Starkloff, Walter Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Catedra de Control de Calidad de Medicamentos; ArgentinaFil: Palma, Santiago Daniel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Unidad de Investigacion y Desarrollo en Tecnologia Farmaceutica; Argentina. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas. Departamento de Farmacia; ArgentinaFil: Gonzalez Vidal, Noelia Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Catedra de Control de Calidad de Medicamentos; Argentin

A New Real-Time Flight Simulator for Military Training Using Mechatronics and Cyber-Physical System Methods

So far, the aeronautical industry has developed flight simulators and space disorientation with high costs. This chapter focuses on the design and implementation process of a low-cost real-time flight simulator for the training of armed force pilots using mathematical models of flight physics. To address such concern, the mathematical models of a Cessna type aircraft have been developed. This has been followed by a flight simulator, which operated with a new construction using a Stewart scale platform and operated by a joystick. Specifically, the simulator has been developed using an approximation of a physical cyber-system and a mechatronic design methodology that consists of mechanical, electrical and electronic elements that control the Stewart platform with three degrees of freedom. Based on software engineering, the algorithms of mathematical and physical models have been developed. These have been used to create an interactive flight simulator of an aircraft based on the Unity 3D game engine platform. The performance of the algorithms has been evaluated, using threads and processes to handle the communication and data transmission of the flight simulator to the Stewart platform. The evaluation of the developed simulator has been validated with professional pilots drilled with the Microsoft Flight Simulator. The results demonstrated that this flight simulator stimulates the development of skills and abilities for the maneuver and control of an aircraft

Identification of fibril-like tertiary contacts in soluble monomeric α-synuclein

Structural conversion of the presynaptic, intrinsically disordered protein α-synuclein into amyloid fibrils underlies neurotoxicity in Parkinson's disease. The detailed mechanism by which this conversion occurs is largely unknown. Here, we identify a discrete pattern of transient tertiary interactions in monomeric α-synuclein involving amino acid residues that are, in the fibrillar state, part of β-strands. Importantly, this pattern of pairwise interactions does not correspond to that found in the amyloid state. A redistribution of this network of fibril-like contacts must precede aggregation into the amyloid structure.Fil: Esteban Martin, Santiago. Barcelona Supercomputing Center. Research Programme in Computational Biology; EspañaFil: Silvestre Ryan, Jordi. Institute for Research in Biomedicine. Research Programme in Computational Biology; EspañaFil: Bertoncini, Carlos Walter. Institute for Research in Biomedicine. Research Programme in Computational Biology; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Salvatella, Xavier. Institute for Research in Biomedicine. Research Programme in Computational Biology; España. Institució Catalana de Recerca i Estudis Avançats; Españ