Revistas Universidad del Bío-Bío
Not a member yet
3557 research outputs found
Sort by
Wood polymer composite bonded veneer based hybrid composites
Get PDFWood veneer based composites have a great demand in present market as the material can utilize small diameter plantation timbers grown at short rotation cycle. This paper presents preparation and characterization of hybrid composites made of wood veneer and wood polymer composite. The study explored utilization of wood polymer composite as an adhesive for bonding veneers replacing formaldehyde-based adhesives. Wood polymer composite containing 40 % bamboo particles embedded in the matrix of polypropylene was used in sheet form to bind the veneers of Melia dubia wood. The composites were prepared in both laminated veneer lumber and plywood configurations. The assessment of physical and mechanical properties indicated that the properties of wood polymer composite contribute significantly to the properties of the hybrid composites. The density of the resultant composites was significantly higher (0,69 g/cm3 – 0,75 g/cm3) than conventional plywood or laminated veneer lumber. Among mechanical properties, there was no statistical difference in tensile and flexural strength of plywood and laminated veneer lumber configuration. Modulus of elasticity and compressive strength of laminated veneer lumber configuration were significantly higher than plywood. Glue shear strength and internal bond strength of the composites indicated acceptable bonding properties of wood polymer composite which suggests the potential application of these composites as a binding agent for wood veneers. These composites could be a special class of laminated composites with no formaldehyde emission hazards
Improving the thermal performance of schools in the High Andean Region of Peru. The case of “PRONIED’S prefabricated frost-type modular classrooms”
Get PDFFrente al déficit cualitativo y cuantitativo de infraestructura educativa en las zonas rurales altoandinas del Perú, el estado peruano ha venido invirtiendo y apostando en los últimos años en soluciones modulares, buscando la eficiencia en los procesos constructivos. La propuesta específica, con énfasis en el diseño bioclimático, es el “Módulo Prefabricado Aula tipo Heladas”; sin embargo, los usuarios han venido manifestando una falta de confort en estos nuevos ambientes. El presente estudio muestra el desarrollo de mediciones realizadas en un módulo construido, que permitieron la calibración y validación del modelo en un software de simulación, con el fin de proponer mejoras en el diseño que aporten a las futuras construcciones. Tomando como referencia el modelo de confort térmico adaptativo, se comprobó que las temperaturas interiores estaban por debajo de la zona de confort en las primeras horas de la mañana y muy por encima cerca del mediodía, alrededor de 6 ºC y 7 ºC respectivamente. Con la aplicación de estrategias bioclimáticas complementarias se logró mejorar considerablemente las condiciones térmicas interiores, aunque no lo suficiente para alcanzar la zona de confort en las primeras horas de la mañana; ello debido a que las temperaturas exteriores nocturnas son muy bajas, a que el edificio está deshabitado toda la noche, a la ausencia de masa térmica en la envolvente y a que no cuenta con sistemas solares activos ni de climatización artificial.Diante do déficit qualitativo e quantitativo de infraestrutura educacional nas áreas rurais alto-andinas do Peru, o Estado peruano vem, nos últimos anos, investindo e apoiando soluções modulares, buscando eficiência nos processos de construção. A proposta específica, com ênfase especial no design bioclimático, é a "Sala de aula modular pré-fabricada do tipo Helada". No entanto, os usuários têm expressado desconforto com essas novas instalações. Este estudo mostra o processo de medição realizado em um módulo construído, que permitiu calibrar e validar o modelo usando um software de simulação, para propor melhorias no projeto que possam contribuir para futuras construções. Tomando o modelo adaptativo de conforto térmico como referência, confirmou-se que as temperaturas internas estavam abaixo dos limites de conforto térmico nas primeiras horas da manhã e bem acima deles perto do meio-dia, em torno de 6 ºC e 7 ºC, respectivamente. Com a aplicação de estratégias bioclimáticas complementares, foi possível melhorar consideravelmente as condições térmicas internas, embora não o suficiente para alcançar o conforto no início da manhã. Isso se deve ao fato de as temperaturas externas noturnas serem muito baixas, de o edifício ficar desabitado durante toda a noite, de não haver massa térmica no envelope e de não haver sistemas solares ativos ou ar-condicionado mecânico.Faced with the qualitative and quantitative deficit of educational infrastructure in Peru’s rural high Andean areas, in recent years the Peruvian State has been investing in and supporting modular solutions, seeking efficiency in the construction processes. The specific proposal, with special emphasis on bioclimatic design, is the "Prefabricated Frost-type Modular Classroom". However, users have been expressing discomfort with these new facilities. This study shows the measurement process carried out on a built module, which allowed calibrating and validating the model using simulation software, to propose improvements in the design that may contribute to future constructions. Taking the adaptive thermal comfort model as a reference, it was confirmed that indoor temperatures were below thermal comfort limits in the early hours of the morning and well above them close to noon, by around 6 ºC and 7 ºC respectively. With the application of complementary bioclimatic strategies, it was possible to considerably improve indoor thermal conditions, although not enough to reach comfort early in the morning. This is because the night-time outdoor temperatures are very low, the building is uninhabited all night long, there is no thermal mass in the envelope, and there are no active solar systems or mechanical air conditioning
Tempo e espaço: As origens portuguesas nas decisões urbanas de Oscar Niemeyer
Get PDF¿Se apropió el urbanismo en Brasil de la tradición urbana en la misma medida que la arquitectura moderna pionera? Este artículo construye una respuesta a esta pregunta, que implica el despliegue teórico de la definición del término espacio a partir del reconocimiento de dos concepciones históricamente aceptadas. Comienza con una breve presentación de las genealogías y principales aspectos de estas concepciones, como soporte metodológico para la lectura de su impacto en la obra de Oscar Niemeyer; rodea las estrategias de diseño en dos obras del arquitecto, el proyecto para la Praça XV en Río de Janeiro (1991) y para el conjunto urbano de Pena Furada, en Portugal (1965). Con nociones tomadas de otros campos disciplinares, se propone una interpretación de la incorporación del tiempo como elemento mediador de la experiencia espacial: como hito literal -impreso en referencias concretas a la tradición- y como elemento generador de decisiones espaciales -al incorporarse a la experiencia del desplazamiento-.Did urbanism in Brazil appropriate the urban tradition to the same extent as pioneering modern architecture? This article builds an answer to this question, which goes through the theoretical unraveling of the definition of the term space from the recognition of two historically accepted conceptions. It starts with a brief presentation of the main genealogies and principles of these conceptions, as methodological support to read their impact on the work of Oscar Niemeyer. It looks at the design strategies used in two works of the architect: the project for Praça XV in Rio de Janeiro (1991) and the urban complex of Pena Furada, in Portugal (1965). With notions borrowed from other disciplinary fields an interpretation of the incorporation of time as a mediating element of spatial experience is proposed: as a literal landmark - printed in concrete references to tradition - and as a generating element of spatial decisions - when incorporated into the experience of displacement.O urbanismo no Brasil se apropriou da tradição urbanística na mesma medida em que a arquitetura moderna pioneira? Este artigo constrói uma resposta a este questionamento, que passa pelo desdobramento teórico da definição do termo espaço a partir do reconhecimento de duas concepções historicamente aceitas. Parte da apresentação breve das genealogias e principais aspectos destas concepções, como suporte metodológico para a leitura de seu rebatimento na obra de Oscar Niemeyer; cerca as estratégias projetuais em duas obras do arquiteto, o projeto para a Praça XV no Rio de Janeiro (1991) e para o conjunto urbano de Pena Furada, em Portugal (1965). Com noções emprestadas de outros campos disciplinares, propõe uma interpretação da incorporação do tempo como elemento mediador da experiência espacial: como marco literal – impresso nas referências concretas à tradição ‒ e como elemento gerador das decisões espaciais ‒ ao ser incorporado na experiência do deslocamento
Fabricación de morteros aligerados con perlita y cal aplicados en paneles con matriz de residuos de paja de arroz
Get PDFThis research aims to design and characterize plaster mortars based on perlite and lime produced in Ecuador, with a minimum compressive strength of 6.89 MPa, as established by IRC 2018, to be applied on rice straw panels. For this purpose, two standard mixes are designed. In the first, sand is used as fine aggregate, while in the second, perlite is used. Eight additional mixes are obtained from each one, where cement is replaced by lime (in volume) in different percentages. A total of 270 test specimens were made to evaluate the compressive strength and density of the mortars at 1, 3, 7, 28, and 50 days. The mortar made with perlite, comprising 50% lime, 50% cement, and an additive, reached a resistance of 7.22 MPa, with a density of 1.45 g/cm³. When this mixture was applied to the rice straw panels, it resulted in an increase of up to 68% in their compressive strength.O objetivo desta pesquisa é projetar e caracterizar argamassas de reboco à base de perlita e cal produzidas no Equador, com uma resistência à compressão mínima de 6,89 MPa, conforme estabelecido pelo IRC 2018. Isso, para ser aplicado em painéis feitos com palha de arroz. Para isso, foram projetadas duas misturas padrão. Na primeira, a areia é usada como agregado fino, enquanto na segunda, é usada perlita. A partir de cada uma delas, são obtidas 8 misturas adicionais, nas quais o cimento é substituído por cal (em volume) em diferentes porcentagens. Foram feitos 270 corpos de prova para avaliar a resistência à compressão e a densidade das argamassas em 1, 3, 7, 28 e 50 dias. A argamassa feita com perlita e composta por 50% de cal, 50% de cimento e aditivo, atingiu uma resistência de 7,22 MPa, com densidade de 1,45 g/cm³. Quando essa mistura foi aplicada aos painéis feitos com palha de arroz, ela resultou em um aumento de até 68% na resistência à compressão.La presente investigación tiene como objetivo diseñar y caracterizar morteros de revoco a base de perlita y cal producida en Ecuador, con una resistencia mínima a compresión de 6.89 MPa, conforme lo establece el IRC 2018. Esto, con el fin de ser aplicado sobre paneles elaborados con paja de arroz. Para ello, se diseñan 2 mezclas patrón. En la primera se usa arena como árido fino, mientras que para la segunda se usa perlita. De cada una se obtienen 8 mezclas adicionales, en las que se sustituye el cemento por cal (en volumen) en diferentes porcentajes. Se realizan 270 probetas con la finalidad de evaluar la resistencia a compresión y la densidad de los morteros a 1, 3, 7, 28 y 50 días. El mortero elaborado con perlita y compuesto por 50% cal, 50% cemento y aditivo, alcanzó una resistencia de 7.22 MPa, con una densidad de 1.45 g/cm³. Al aplicar esta mezcla sobre los paneles elaborados con paja de arroz, dio como resultado el aumento de su resistencia a compresión hasta un 68%
Propósitos formativos en la enseñanza de la historia. Continuidades y cambios en las reformas curriculares
Get PDFEl artículo corresponde a una investigación que indagó en los textos visibles correspondiente a las bases curriculares para la enseñanza de la historia en Chile en educación media entre los años 1998 y 2015, periodo en el cual se desarrollaron tres procesos de renovación curricular. Se buscó develar los propósitos formativos con la finalidad de determinar sus énfasis, continuidades y cambios. La metodología se desarrolla en el marco de un diseño de investigación cualitativo desde un paradigma comprensivo interpretativo. Los resultados muestran que los propósitos formativos se desarrollan en dos dimensiones: explícitos, enfocados en el desarrollo de conocimientos, habilidades y actitudes; e implícitos, vinculados a la instalación del componente identitario. Esta último se posiciona como una persistencia. Respecto de las transformaciones, estas se manifiestan en los contenidos y formas, incorporando nuevas temáticas y dimensiones. Se concluye que la evolución curricular ha implicado cambios en los propósitos formativos en cuanto a sus formas, plasmadas en cuestiones procedimentales de corte pedagógico curricular; no obstante, sus finalidades nacionalizantes originarias, se mantienen sin mayores alteraciones.The article corresponds to an investigation that investigated the visible texts corresponding to the curricular bases for the teaching of history in Chile in secondary education between the years 1998 and 2015, a period in which three curricular renewal processes were developed. It was sought to reveal the formative purposes in order to determine their emphasis, continuities and changes. The methodology is developed within the framework of a qualitative research design from a comprehensive interpretive paradigm. The results show that the training purposes are developed in two dimensions: explicit, focused on the development of knowledge, skills and attitudes; and implicit, linked to the installation of the identity component. The latter is positioned as persistence. Regarding the transformations, these are manifested in the contents and forms, incorporating new themes and dimensions. It is concluded that the curricular evolution has implied changes in the formative purposes in terms of its forms, embodied in procedural questions of a curricular pedagogical nature; However, its original nationalizing purposes are maintained without major alterations
Antecedentes sobre la inserción socioeconómica de la comunidad italiana en Arica (1885-1903)
Get PDFThe main objective of this article is to describe and analyze the socioeconomic insertion of the Italian community residing in the city of Arica in the period between the years 1885-1903, through the review of documentary and newspaper sources, identifying the main economic and social activities in which they participated, understanding these as tools of their insertion and integration in the local society.
El objetivo central de este artículo es describir y analizar la inserción socioeconómica de la comunidad italiana residente en la ciudad de Arica en el periodo que comprende los años 1885-1903, a través de la revisión de fuentes documentales y hemerográficas, identificando las principales actividades económicas y sociales en las que participaron, entendiendo a estas como herramientas de su inserción e integración en la sociedad local.
 
Entre chuicos y damajuanas: Pauperización de la vida campesina en Ñuble (Chile), 1960-1980
Get PDFEl estudio, a través de una metodología cualitativa, revisa algunos aspectos de la vida campesina durante la segunda mitad del siglo XX en la antigua provincia de Ñuble, identificando cómo la presencia del alcoholismo transformaba los espacios, ralentizaba la producción agrícola, violentaba a las familias de la época, y empobrecía a las comunidades. Este proceso, denominado pauperización, deja en evidencia uno de los aspectos de la ocupación humana en el campo chileno, en este caso el trastoque de los roles de los miembros de la familia campesina, donde el hombre dejaba de ser un proveedor y protector de la misma para convertirse por efecto del alcohol en un agente disruptor en la sociedad, plantea una posibilidad de análisis para determinar condiciones de pobreza en algunos sectores rurales de Ñuble.
The study, through a qualitative methodology, reviews some aspects of peasant life during the second half of the 20th century in the former province of Ñuble, identifying how the presence of alcoholism transformed the spaces, slowed down agricultural production, ravaged the families of that period, and impoverished the communities. This process, called pauperization, highlights one of the aspects of human occupation in the Chilean countryside, in this case the change in the roles of the members of the peasant family, where the man ceased to be a provider and protector of the family and became a disruptive agent in society due to the effect of alcohol. This raises a possibility of analysis to determine the conditions of poverty in some rural sectors of Ñuble.
 
El Diablo en Chile Colonial. Alhué 1792
Get PDFThe study recounts the case of Santiago Barreta, accused of repeated rape against his daughters in the town of Alhue in 1792. However, what is interesting is the curious attribution of guilt to the Devil.
It is recognized that, despite the influence of the European Enlightenment, traditional beliefs rooted in divine law persisted in Chile at the time, where sin and crime were intertwined.
The study, heuristic in nature, becomes a tool to understand how these popular beliefs and reality merge into a single structure. In this case, the Devil becomes the scapegoat, a reflection of the influence he exerts on society, beyond his real history, which is inaccessible except through human perceptions, making imaginary representations become real to the extent that society accepted them as truths rooted in its cultural heritage.
El estudio narra el caso de Santiago Barreta, acusado de estupro reiterado contra sus hijas, en la localidad de Alhue en 1792. Sin embargo, lo interesante del mismo es la curiosa atribución de culpabilidad al Diablo.
Se reconoce que, a pesar de la influencia de la Ilustración europea, en el Chile de la época persistían creencias tradicionales arraigadas en el derecho divino, donde el pecado y el delito estaban entrelazados.
El estudio, de carácter heurístico, se convierte en una herramienta para entender cómo estas creencias populares y la realidad se fusionan en una estructura única. En este caso, el Diablo se convierte en el chivo expiatorio, un reflejo de la influencia que ejerce en la sociedad, más allá de su historia real, que es inaccesible excepto a través de las percepciones humanas, haciendo que las representaciones imaginarias se volvieran reales en la medida en que la sociedad las aceptaba como verdades arraigadas en su acervo cultural
Plan de internacionalizacion de universidades regionales chilenas
Get PDFUniversidad Técnica Federico Santa María (UTFSM) nace gracias a la visión filantrópica de Don Federico Santa María. Se encuentra localizada en Valparaíso, pero también cuenta con sedes en Santiago y Concepción. La internacionalización de las universidades chilenas es alta en el caso de la investigación, sin embargo, en materia de sedes de las universidades chilenas en el extranjero es casi nula. En este artículo se propone la internacionalización de la UTFSM en la región de Cuyo (Provincia de Mendoza, Provincia de San Juan y Provincia de San Luis), tomando como base las relaciones históricas entre Chile y Argentina, las cuales nacen mucho antes del proceso independentista latinoamericano. Se concluye que existen diferentes maneras para lograr esta internacionalización como la apertura de sedes o el intercambio académico.Universidad Técnica Federico Santa María (UTFSM) borns by the philantropic vision of Federico Santa María. It is in Valparaíso, but it also has presence in Santiago and Concepción. The internationalization of Chilean universities is high in the case of research, however, the physical presence of Chilean universities in another country it is almost nil. This article proposes the internationalization of UTFSM in Cuyo region (Mendoza Province, San Juan Province and San Luis Province), based on the historical relation between Chile and Argentina, even before the independent process. It is concluded that there are different ways to achieve this internationalization such as the opening of campus or academic exchange
Assessment of cellulose nanofibers from bolaina blanca wood obtained at three shaft heights
Get PDFThis study evaluated cellulose nanofibers from bolaina blanca wood (Guazuma crinita) obtained at different heights of the longitudinal axis of the shaft of trees from a three-and-a-half-year-old plantation. The wood was subjected to pulping, bleaching and subsequent mechanical milling using a Changsha Samy XYQM-2L planetary ball mill to obtain cellulose nanofibers. The product was characterised using analytical techniques: scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy. Additionally, the degree of polymerisation was determined. The effect of longitudinal position on cellulose nanofibers characteristics was evaluated by comparing means using ANOVA and Kruskal–Wallis statistical tests. The yield of cellulose nanofibers production from the high, middle and basal sections was 32,1 %, 33,6 % and 31 %, respectively. The obtained cellulose nanofibers exhibited a significantly larger diameter for the high zone (84 nm) compared with the middle (75 nm) and basal (69 nm) zones; the length remained above the micrometre range. With respect to degree of polymerisation, a decrease was evidenced with respect to the increase in shaft height; the basal zone exhibited a degree of polymerisation of 300, a significantly higher value than the middle and high zones, which exhibited degree of polymerisation of 249 and 211, respectively. The product showed typical cellulose type I polymorphism and crystallinity indexes of 76 %, 93 % and 96 % for the high, middle and basal sections, respectively. Regarding the thermostability of cellulose nanofibers, the maximum degradation rate of cellulose nanofibers occurred between 335 °C and 341 °C, with cellulose nanofibers from the basal area being the most stable. The adsorption of the methylene blue dye on cellulose nanofibers was evaluated; an efficiency > 60 % was found