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espanolLa presente investigacion tiene como proposito indagar ciertos aspectos relacionados con el discurso nacional de principios del siglo XX, centrando nuestra atencion en un amplio reportaje acerca de Arica y Tacna publicado por entregas en el diario La Union de Valparaiso en diciembre de 1922, momento de tension diplomatica entre Peru y Chile cuyo entorno era una posible definicion plebiscitaria de los limites de la nueva frontera norte. Este tipo de reportajes -que basaban su efectividad en la conjuncion entre imagenes fotograficas y textos- fueron utilizados como una postura periodistica que se correspondia con la alianza practicada entre las politicas de chilenizacion del Estado y las empresas editoriales para crear y fomentar un imaginario nacionalista postguerra del Pacifico. En este sentido, la intencionalidad estrategica del reportaje de La Union consistio en replicar una idea general pre concebida, estereotipada, que daba a entender la conveniencia de que los territorios ocupados y aun en disputa continuaran bajo el dominio de Chile, debido a que el pais era el mas apto para ejercer el progreso y la modernizacion. Estos intereses se habian tornado esenciales para la elite portena, que fue la tribuna hacia donde apunto en especial el diario. EnglishThis investigation aims to look at certain issues related to Chile's national discourse at the beginning of the twentieth century, focusing our attention on a wide-ranging report about Arica and Tacna published in installments in the newspaper La Union in December 1922. A moment of diplomatic tension between Peru and Chile whose backdrop was the possible definition of the new northern border's boundaries through a plebiscite. This kind of report - whose effectiveness was based on bringing photographic images and text- was used as a journalistic position that corresponded with the alliance between the State and the press over the policies of "Chilenisation" to create and encourage nationalist sentiment after the War of the Pacific. In this sense, the report's strategic intention in La Union consisted in replicating a preconceived and stereotypical general idea that held that it was con venient for the occupied territories still in dispute to continue under Chilean rule since the country was better suited to bringing progress and modernization. These interests had become essential for Valparaiso's elite, the audience at which the newspaper was aiming in particular.

This paper presents practical aspects related with the operation, compensation, and protection of high-power cycloconverters used in the mining industry. Practical recommendations related with startup, compensation requirements, operational characteristics, and unexpected shutdown process are described. Fuseless characteristics of modern cycloconverters are also discussed. Relevant current waveforms associated with the operation of a 20-MW synchronous motor semiautogenous grinding mill drive are presented, as well as current and voltage waveforms under fault operating conditions.

Se trata de una entrevista sostenida con el historiador frances Francois Hartog con ocasion de su visita a Valparaiso a fines del 2013. Se abordan aqui topicos de su obra, como su tesis de que vivimos una epoca signada por un “regimen de historicidad presentista”, el significado de la sobreproduccion de patrimonio, el boom de la memoria y la vinculacion entre bloqueo del horizonte de futuro y una ideologia dominante.

En el presente articulo se plantea el problema que significa la desaparicion de la historiografia moderna y la extincion de la memoria social, ambas formas de acceder al pasado destinadas a una mutua interpelacion critica. En su lugar hoy tendriamos dos formas equivalentes a ellas, pero que, en cambio, conviven en un acuerdo implicito: localismo patrimonial y patrimonialismo “desde abajo”. Serian formas propias de un “presentismo radical” que obturan la posibilidad de la historia como disciplina y como campo significativo de la accion humana. Palabras claves: Patrimonio, historiografia, memoria social, presentismo.

El presente texto pretende problematizar la enseñanza de la historia, proponiendo como hipótesis que la especificidad de la historia, en tanto disciplina (historiografía), es diluida en las estrategias ‘didácticas’ más extendidas entre los profesores. Este extravío es digno de investigar no por un mero celo disciplinario, sino debido a las consecuencias que puede tener en las valoraciones, decisiones y acciones futuras de los alumnos. Se plantea que la construcción de una representación del mundo histórico, como la que se delinea a partir de las actuales prácticas pedagógicas, no hace más que reforzar ciertas ideas arraigadas en el sentido común, impidiendo cualquier cambio conceptual y desestimando la historicidad de los propios estudiantes.

El presente trabajo busca establecer un contraste entre el recurso político del pasado y sus actuales usos meramente es­tetizantes. En este sentido, la obra de Ma­riátegui, en particular su exigencia de co­nocimiento de la realidad histórica del Perú para una transformación revolucionaria, es situada en el momento de “crisis” en que se formula. Momento en el cual la pregunta por la historia –como modalidad de la pre­gunta por el sentido– adquiere primordial urgencia para iluminar el futuro. Así este trabajo recupera la Filosofía de la Historia como actividad reflexiva que busca conectar nuevamente el discurso de la historia con el de la acción.

This paper presents a method for predicting the flicker level that is generated by the high-power load in a distribution system. Through the development of the Flickermeter that met the International Electrotechnical Commission requirements, a reference curve is obtained based on the variation of voltage and the amount of changes per minute of the load. The purpose of this prediction is to determine if the load operation will produce flicker before being connected to the electrical system. This analysis cannot be developed by power system software due to the Flickermeter complexity and the amount of data that is required for processing.

This paper presents a filter scheme implemented with passive high-pass filters and a shunt active power filter. The filter scheme is aimed to compensate high power cycloconverter drives used in grinding mill plant. Passive filters are used to compensate power factor and characteristics current harmonic components generated by the cycloconverter, while the shunt active filter is designed to compensate only the low frequency sub and inter-harmonics generated by the cycloconverter. The principal advantage of the proposed scheme is that it allows effective attenuation of all the harmonic components resulting from cycloconverter input currents, meeting IEEE Std. 519. Simulated results of a large grinding mill plant compensated with the proposed filter scheme prove the compensation effectiveness.

This paper presents a filter scheme composed by passive and series active power filters specially designed to compensate fundamental reactive power (with passive filters) and current harmonics (combination of passive and active). Low frequency current sub and inter-harmonics generated by cycloconverters are eliminated with an active power filter connected in series to a C type passive filter. Current frequency harmonics associated with cycloconverter topology are eliminated with passive filter units. With the proposed filter topology compensation effectiveness is significantly improved and allows the elimination of passive filter units, reducing cost and space required as compared with traditional passive schemes. This paper presents the principles of operation and design requirements of the proposed hybrid filter scheme. Simulated results based in the compensation of a real grinding mill plant prove the effectiveness and advantages of the proposed scheme.

This paper presents a design method for passive filters used to compensate power factor and current harmonics generated by high power cycloconverter drives. The paper includes the analysis of different passive filter topologies effectiveness (band-pass, high-pass and C type), a procedure to calculate filter parameters, tuning frequency selection, and reactive power distribution. The passive filters are designed to compensate high power grinding mill drives energized from cycloconverters. Simulated results based on a real grinding mill plant prove the effectiveness of the proposed method.