Feasibility of Laminar Plasma-Jet Hardening of Cast Iron Surface

Nontransferred DC laminar plasma jets of stable flow and low impinging pressure acting on the substrate were used to heat W–Mo–Cu cast iron for phase transfer hardening of the surface layer. Substrates were heated in multipass with or without overlapping or heated with only single-pass. Surface morphologies of the molten trace and microstructure of the cross-section were observed, and the hardness distribution of the treated surface layer was examined. The surface layer of single-pass-heated specimen has an average hardness of about 900 HV0.1, while the specimen treated with multipass shows an average hardness of about 700 HV0.1, because of the heat effect from the neighboring pass treating, compared with the substrate hardness of about 300 HV0.1. The results demonstrate the stable and favorably controlled heating of the laminar plasma jet on the substrate surface and feasibility of using it as a tool for surface hardening of cast iron.

Application of Three-Dimensional Discrete Element Face-to-Face Contact Model with Fissure Water Pressure to Stability Analysis of Landslide in Panluo Iron Mine

Three-dimensional discrete element face-to-face contact model with fissure water pressure is established in this paper and the model is used to simulate three-stage process of landslide under fissure water pressure in the opencast mine, according to the actual state of landslide in Panluo iron mine where landslide happened in 1990 and was fathered in 1999. The calculation results show that fissure water pressure on the sliding surface is the main reason causing landslide and the local soft interlayer weakens the stability of slope. If the discrete element method adopts the same assumption as the limit equilibrium method, the results of two methods are in good agreement; while if the assumption is not adopted in the discrete element method, the critical phi numerically calculated is less than the one calculated by use of the limit equilibrium method for the same C. Thus, from an engineering point of view, the result from the discrete element model simulation is safer and has more widely application since the discrete element model takes into account the effect of rock mass structures.

Pleitos y usurpaciones de tierras realengas en Córdoba a fines del siglo XV : la villa de Las Posadas

Resumen: Analizamos el problema de las apropiaciones ilícitas de tierras en el término jurisdicional de la ciudad de Córdoba a fines de la Edad Media, centrando la atención en la villa de Las Posadas y en los procesos judiciales.

The production of separate streams of pure hydrogen and carbon dioxide from coal via an iron-oxide redox cycle

A chemical looping process using the redox reactions of iron oxide has been used to produce separate streams of pure H2 and CO2 from a solid fuel. An iron oxide carrier prepared using a mechanical mixing technique and comprised of 100wt.% Fe2O3 was used. It was demonstrated that hydrogen can be produced from three representative coals - a Russian bituminous, a German lignite and a UK sub-bituminous coal. Depending on the fuel, pure H2 with [CO] ≲50vol.ppm can be obtained from the proposed process. The cyclic stability of the iron oxide carrier was not adversely affected by contaminants found in syngas which are gaseous above 273K. Stable quantities of H2 were produced over five cycles for all three coals investigated. Independent of the fuel, SO2 was not formed during the oxidation with steam, i.e. the produced H2 was not contaminated with SO2. Since oxidation with air removes contaminants and generates useful heat and pure N2 for purging, it should be included in the operating cycle. Overall, it was demonstrated that the proposed process may be an attractive approach to upgrade crude syngas produced by the gasification of low-rank coals to pure H2, representing a substantial increase in calorific value, whilst simultaneous capturing CO2, a greenhouse gas. © 2010 Elsevier B.V.

Bronze and iron weapons from Luristan

The 30,000 km2 province of Luristan is situated in western Iran and encompasses the upper valleys of the Zagros Mountains. Even today, local tribesmen inhabit Luristan with their settlement patterns similar to ancient times. Several scientific excavations in the Luristan region have uncovered evidence that this particular region was a major attraction for human settlements from the Paleolithic era onwards. In Ancient Iran, the existence of rich mines together with discoveries made by innovative and inventive artisans spurred the growth of the metalworking culture as an art and a skill among early human communities in Ancient Iran. The art of Luristan can be described as the art of nomadic herdsmen and horsemen with an emphasis on the crafting of small, easily portable objects, among these a number of bronze daggers, swords and other weapons. Throughout its history, Luristan was never an ethnic or political entity because Luristan has been occupied by various tribes and races, throughout its history. Next to Elamites, other tribes who inhabited Luristan were the Hurrians, Lullubians, Kutians, and Kassites. As local tribesmen of Luristan were illiterate, information about their history can only be partially reconstructed from the literature of their southern neighbors: the Elamites and Babylonians. Luristan smiths made weapons for both civilizations. The region was later invaded by Assyrians and finally the Iranians settled the area and absorbed the local tribes. Following an accidental find by the local inhabitants in Luristan in 1928 CE, a number of unlawful diggings reveal a number of metal objects made of bronze and iron that showed a high level of craftsmanship. These objects were offered for sale on the art market with fancy names to hide their origin. The subsequent scientific excavations several decades after the initial discovery provided fascinating information about the culture of Luristan. The metalworking art of Luristan spans a time period from the third millennium BC to the Iron Age. The artifacts from Luristan seem to possess many unique and distinctive qualities, and are especially noteworthy for the apparently endless, intricate diversity and detail that they characteristically depict. The bronze artifacts found in or attributed to Luristan can be each be classed under five separate heads: a) arms and armor, including swords, dirks, daggers, axes, mace heads, spearheads, shields, quiver plaques, protective bronze girdles, helmets; b) implements related to horsemanship, including decorative or ornamental objects for horses as well as bits and snaffles; c) items for personal adornment and hygiene, including anklets, bangles, bracelets, finger rings, earrings and tweezers; d) ceremonial and ritual objects, including talismans, idols, pins, anthropomorphic and zoomorphic figurines; and e) utilitarian objects comprising various vessels and tools, including beakers, bowls and jugs. The scope of this article is limited to a discussion of the bronze and iron weapons made in Luristan. The techniques used for making bronze weapons in Luristan included: casting with open molds, casting with close molds, and casting with lost wax process. For metal sheets used for quiver plaques and bronze protective belts, the hammering technique was used. Edged weapons made in Luristan can be classified into: a) daggers, dirks, and swords with tangs; b) daggers, dirks, and swords with flanges; and c) daggers, dirks, and swords with cast-on hilts. Next to bronze, iron was also used for making weapons such as the characteristic weapon from this area, the iron mask sword.

Propiedad privada, abasto y regulación del comercio y la circulación de mercancías en la campaña de Buenos Aires : desde fines de la colonia al gobierno de Martín Rodríguez

Resumen: El artículo indaga en la fiscalidad sobre el comercio interior de Buenos Aires y su relación con la consolidación de la propiedad privada en la campaña. A partir de un estudio de caso, se examinan las particularidades de las imposiciones fiscales sobre las actividades comerciales en el ámbito rural identificando cambios y continuidades en las formas de recaudación y gravamen. Este análisis se combina con el de los problemas que las prácticas ilegales vinculadas al abasto de ganado presentó tanto en su circulación en la campaña como en su introducción a los mercados citadinos. Ambas cuestiones son contrastadas con lo sucedido a partir de 1822, cuando durante el gobierno de Martín Rodríguez tanto el comercio como la circulación de ganado en el Hinterland intentarían ser regulados con mayor énfasis a fin de asegurar el respeto de la propiedad privada en el mundo rural.

Nonequilibrium microstructures and phase evolutions of an iron-based laser clad coating

The microstructural and compositional features of the laser-solidified microstructures and phase evolutions occurring during high temperature tempering were investigated by using analytical electron microscopy with energy dispersive X-ray analysis. The cladded alloy, a powder mixture of Fe, Cr, W, Ni and C with a weight ratio of 10:5:1:1:1, was processed with a 3 kW continuous wave CO2 laser. The cladded coating possessed the hypoeutectic microstructure of the primary dendritic gamma-austenite and interdendritic eutectic consisting of (gamma+M7C3). The gamma-austenite is a nonequilibrium phase with extended solid solution of alloying elements. And, a great deal of fine structures, i.e., a high density of dislocations, twins, and stacking faults existed in austenite phase. During high temperature aging, the precipitation of M23C6, MC and M2C in austenite and in situ transformation of M7C3(+gamma) --> M23C6 and M7C3+gamma --> M6C occurred. The laser clad coating revealed an evident secondary hardening and superior impact wear resistance.

Rapidly solidified nonequilibrium microstructure and phase transformation of laser-synthesized iron-based alloy coating

The rapidly solidified microstructural and compositional features, the precipitation and transformation of carbides during tempering, and the impact wear resistance of an iron-based alloy coating prepared by laser cladding are investigated. The clad coating alloy, a powder mixture of Fe, Cr, W, Ni, and C with a weight ratio of 10:5:1.1.1, is processed using a continuous wave CO, laser. Microstructural studies demonstrate that the coating possesses the hypoeutectic microstructure comprising the primary dendritic gamma-austenite and interdendritic eutectic consisting of gamma-austenite and M7C3 carbides. gamma-Austenite is a non-equilibrium phase with an extended solid solution of alloying elements. During high temperature tempering at 963 K for 1 h, the precipitation of M23C6, MC and M2C carbides in austenite and in situ carbide transformation of M7C3 to M23C6 and M7C3 to M6C respectively are observed. In addition, the microstructure of the laser-clad coating reveals an evident secondary hardening and a superior impact wear resistance.

Extracción de órganos de cadáveres con fines de trasplante. Voluntariedad y consentimiento presunto

El tema del llamado “consentimiento presunto” a los fines de habilitar la extracción de órganos cadavéricos ha suscitado debate e interés en ámbitos bioéticos y biojurídicos. Cuestiones como la del valor y significado del cuerpo y el cadáver, la relación entre el individuo y la comunidad, el papel de la voluntad y la libertad en las decisiones relacionadas con el propio cuerpo, tienen aquí especial relevancia. Varias leyes han tratado estos temas y distintos países se rigen por diferentes sistemas. La gran pregunta que recorrerá este trabajo se remite al papel y relevancia que se considera debe darse a la voluntad del difunto a la hora de disponer de sus órganos para trasplante.

Potencial escénico de la Reserva Natural Cerro Datanli-El Diablo en Jinotega, con fines eco turisticos

El estudio fue realizado en la RN Cerro Datanlí- El Diablo, Jinotega. El objetivo principal fue identificar sitios con potencial belleza escénica aun no considerados para la ejecución de actividades ecoturísticas que tiendan a mejorar la calidad de vida de sus pobladores locales a partir de la visita de turistas y nacionales. Los mejores atractivos naturales e infraestructura existente se homogenizaron mediante la consulta a lugareños y a través de la observación personal . La metodología se desarrolló en tres etapas: (1) Recolección de la información secundaria, selección y ubicación de la zona de estudio y de contactos (MARENA, PAGJINO, Líderes locales). (2) Giras de campo para llevar a cabo: el DRP auxiliado con tres herramientas participativas; la identificación de 22 sitios con potencial ecoturístico, 3 problemas principales que limitan su desarrollo, recorridos por 7 senderos ecológicos que facilitó la identificación de 17 sitios posibles como miradores de paisajes diversos y 5 sitios donde se pueden observar y escuchar cantar aves exóticas como el Quetzal; aplicación de encuestas a los pobladores locales (niños y jóvenes ambientalistas, mujeres y productores) con el fin de conocer su participación en actividades de protección, conservación y manejo de los recursos naturales. (3) Elaborar los mapas de los senderos a través del programa Arc View 3.2, se ubicaron los principales atractivos, propuestas de cambios en los recorridos basados en pendientes del terreno, análisis de visibilidad de miradores ysegún los atractivos principales en los sendero. La información facilitó incluir el diseño de un modelo de infraestructura en los senderos (gradas, miradores y puentes) para el tráfico de visitantes y la elaboración de tres propuestas de paquetes turísticos que contienen información básica de los recursos naturales existentes en la reserva natural.

Recently discovered Iron Age lion figurines from Jerusalem

Abstract: More than 500 Iron Age figurines were discovered in the 2005–2010 Western Wall Plaza excavations in Jerusalem.1 The excavations revealed a large building, probably of the four-room type. Many figurines were discovered in this building, others in fills below and above it, dating in general to the eighth-sixth centuries BCE. Here we focus on two heads most likely depicting lions, one of them exceptional—holding another animal in its mouth. We discuss the identification of these figurines as lions, the lion motif in a variety of media in the Southern Levant, and finally recent theories concerning lions in the Hebrew Bible and their relation to Yahweh. We suggest that the two Western Wall Plaza figurines represent lions as wild animals, in similarity to other figurines of wild animals made on occasion by Judean coroplasts.

Recuperar plásticos desechables a los fines de conformar elementos constructivos de una vivienda económica como respuesta social, analizada como un problema de ingeniería industrial

Resumen: El hecho de seleccionar a los plásticos dentro de nuestro proyecto es porque son en particular, partes abundantes y visibles en la composición de los residuos generados en nuestra sede UCA Campus Rosario. Razonamos que son varias las áreas que los producen en forma cotidiana o de modo transitorio (como es el caso de eventos), a las que podemos sumar un accionar ambientalmente responsable. Ello nos impone la responsabilidad de proponer algún modo de re-utilizarlos en el diseño de ciertos elemento que los integre como materia prima, material de aporte, insumo o material auxiliar, con un amplio campo de posibilidades como es en la construcción, a partir de una mirada desde la ingeniería ambiental. La metodología de trabajo que desarrollamos implica inspeccionar la materia prima con la cual se va a trabajar, a los fines de conocerla fehacientemente, así como internalizar la posible combinación entre los distintos tipos de plásticos de acuerdo a su composición y su respuesta en la integración con otros materiales de uso tradicional, de acuerdo a experiencias reconocidas Desde una mirada lineal la educación sola no alcanza, como tampoco la tecnología ni las medidas parciales son suficientes para aliviar este tremendo desequilibrio que venimos heredando. Ante estos hechos es perentorio comprender la complejidad, actuar desde allí descubriendo la conexión invisible entre el ser humano y el medio, y los seres humanos entre sí. Debido a ello entendemos que para restaurar el medio ambiente en principio hay que comenzar por restaurar los vínculos y los ciclos que los contienen, esto implica re-ciclar.

La inmigración colonizadora en Santa Cruz entre fines del siglo XIX y principios del siglo XX

Resumen: La inmigración colonizadora que recibió el entonces Territorio Nacional de Santa Cruz configuró sus características principales. Este fenómeno se originó a partir del ingreso de un número importante de individuos de diferentes nacionalidades que buscaban insertarse en un mundo diferente y en un nuevo mercado laboral. Esto afectó a la estructura social, económica, cultural y aun política de ese momento. Dentro de este proceso que afectó a todo el territorio nacional, uno de los casos más singulares es el desarrollo poblacional de los colonos de Santa Cruz a fines del siglo XIX y principios del siglo XX. La misma presente particularidades que merecen un análisis particular y detallado.