Revistas Universidad del Bío-Bío
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La filosofía y el sabio estoico: Examen de la virtud
Get PDFEl hombre, para los estoicos debe conocer todo aquello que le permita conseguir la felicidad, primordialmente la felicidad interior, y no el goce de las cosas externas.
La filosofía, para los estoicos, en general, era en primera instancia una necesidad, una forma de vida, que no persigue utilidad alguna. Con la aparición de "la filosofía estoica" en la historia ya no se busca solamente la verdad, sino más bien, un repertorio de nuevas convicciones que le ayuden a un buen vivir suyo, ejercicio esencial es la búsqueda de la "felicidad".
El estoico se vuelve a la filosofía, pero no en un sentido original, sino que busca en ella, un sustituto de las convicciones políticas, sociales y religiosas, es decir, un sustituto de las cuestiones éticas. La filosofía se transforma en una norma de vida, en una especie de religiosidad, que va, en definitiva, a permitirle vivir. De aquí surge la "doctrina estoica" como una respuesta a los tiempos nuevos, a través de una moral de aguante.
La filosofía estoica da paso a la elaboración de las cuestiones más importantes de la vida individual de la época histórica que le correspondió vivir
Patrimonio geomorfológico del Paso Pehuenche, Mendoza, Argentina
Get PDFThe relief is a natural asset that has suffered the impact of aggressive anthropic activities on numerous occasions and, however, it is rarely considered when taking preservation measures as its heritage value is unknown. El Paso Pehuenche located in the province of Mendoza and linking Argentina with Chile, has an interesting and varied relief composed of structural and climatic morphologies that it was considered necessary to know and interpret in order to later inventory its Geomorphological Heritage Sites. This selection was achieved based on the scientific value of the geoforms, taking into account parameters such as rarity, diversity, representativeness, integrity, scientific knowledge and observation conditions. Added to the scientific value was the evaluation of added values, of use and of susceptibility to degradation in each selected site to determine the management value that allows establishing management priorities and recommending concrete actions for the protection and conservation of the geomorphological heritage of the area. The work finally proposes dissemination and awareness strategies towards the local population and visitors of the international passage to achieve the objective of a sustainable public use of the relief by knowing its heritage potential and achieving its enjoyment by current and future generations.El relieve es un bien natural que en numerosas ocasiones ha sufrido el impacto de actividades antrópicas agresivas y, sin embargo, rara vez es considerado al momento de tomar medidas de preservación al desconocer su valor patrimonial. El Paso Pehuenche ubicado en la provincia de Mendoza y que vincula Argentina con Chile, posee un interesante y variado relieve compuesto por morfologías estructurales y climáticas que se consideró necesario conocer e interpretar para posteriormente inventariar sus Sitios Patrimoniales Geomorfológicos. Esta selección su logró en función del valor científico de las geoformas teniendo en cuenta parámetros como rareza, diversidad, representatividad, integridad, conocimiento científico y condiciones de observación. Al valor científico se sumó la evaluación de valores añadidos, de uso y de susceptibilidad a la degradación en cada sitio seleccionado para determinar el valor de gestión que permite establecer prioridades de manejo y recomendar acciones concretas para la protección y conservación del patrimonio geomorfológico del área. El trabajo finalmente propone estrategias de difusión y sensibilización hacia la población local y visitante del paso internacional para lograr el objetivo de un uso público sustentable del relieve al conocer su potencial patrimonial y lograr su disfrute por parte de generaciones actuales y futuras
Combining artificial neural network and moth-flame optimization algorithm for optimization of ultrasound-assisted and microwave-assisted extraction parameters: Bark of Pinus brutia
Get PDFIn this study, the extraction parameters of Pinus brutia bark were optimized using a hybrid artificial intelligence technique. Firstly, the bark samples were extracted by ultrasound-assisted extraction and microwave-assisted extraction which are defined as ‘green’ extraction methods at different conditions. The selected extraction parameters for ultrasound-assisted extraction were 0:100; 20:80; 40:60; 80:20 (%) ethanol: water ratios; 40 ºC, 60 °C extraction temperatures and 5 min, 10 min, 15 min, 20 min extraction times and for microwave-assisted extraction were 90, 180, 360, 600, 900 (W) microwave power, 0:100; 20:80; 40:60; 60:40; 80:20 (%) ethanol: water ratios. Then Stiasny number, condensed tannin content and reducing sugar content of all extracts were determined. Next, the prediction models were developed for each studied parameter using Artificial Neural Network. Finally, the extraction parameters were optimized using Moth-Flame Optimization Algorithm. After that optimization process, while the extraction time was the same (5 min), the ethanol: water ratio and extraction temperature values differed for the optimization of all studied assays of ultrasound-assisted extraction. Also, microwave power and ethanol: water ratio variables were found in different values for each assay of microwave-assisted extraction. The results showed that the Artificial Neural Network and Moth-Flame Optimization could be a novel and powerful hybrid approach to optimize the extraction parameters of Pinus brutia barks with saving time, cost, chemical and effort
Lumber drying of pinus: Geostatistics applied to drying kilns
Get PDFThis study aimed to evaluate the spatial distribution of the air circulation speed and the final moisture content of pine lumber after kiln drying by using geostatistics. Two kilns acting on boards of 27 mm and 42 mm were evaluated. Air circulation speed and final moisture content were collected in different regions of the kilns. There was no significant difference for air circulation speed and final moisture content between the front and rear regions of the equipment. In the horizontal axis (Y-axis), air circulation speed averages did not differ statistically in both situations, but higher values for this variable were obtained from the spaces between the piles. Final moisture content tended to increase when closer to the door opening. In the vertical axis (Z-axis), the lower part tended to reach higher air circulation speed values. Thus, the spatial behavior influences the air circulation speed and final moisture content during lumber drying. Besides, the variograms presented the same tendency in comparison to the data obtained in a conventional manner, which indicates that geostatistics can be used to represent variables in kilns during the drying process
Wettability and decay of particleboards manufactured with thermally treated sugarcane residue and bamboo (Dendrocalamus asper) particles
Get PDFThis study aimed to evaluate the chemical composition of wood particles (control and treated), and the effects of thermal modification and adhesive levels on the wettability and biological resistance of particleboards made of sugarcane residue and bamboo (Dendrocalamus asper). Therefore, 75% bamboo particles and 25% sugarcane residue (bagasse) were used for producing the particleboards. The particles were treated at 220 °C for 3h35min. Urea formaldehyde (UF) adhesive was used in three solid contents (10%, 12% and 14%) based on the dry mass of the particles. The mat was cold pre-consolidated (pressure of 0,5 MPa for 5 min) and after hot consolidated (3,45 MPa, 180 ºC, 10 min). Water and ethylene glycol and two measurement times were used to measure the contact angle. Gloeophyllum trabeum and Rhodonia placenta (brown rot) and Trametes versicolor (white rot) fungi were used for the biological resistance test. There was a change in the chemical composition of the treated particles such as a reduction in the levels of lignin (bagasse and bamboo), total extracts and holocellulose (bagasse). The thermal treatment increased the final contact angles obtained with water. The particleboard surfaces were classified as non-wettable and partially wettable to the tested solvents. The thermal treatment provided biological resistance improvements in the particleboards to the tested fungi, being classified as very resistant to Rhodonia placenta, resistant to very resistant to Gloeophyllum trabeum, and moderate to resistant to Trametes versicolor
Performance of cement-bonded wood particleboards produced using fly ash and spruce planer shavings
Get PDFThe aim of this research was to investigate the physico-mechanical, thermal, and morphological properties of cement-bonded wood particleboards produced by using fly ash as a partial cement replacement and spruce planer shavings. Experimental single-layer cement-bonded wood particleboards produced using a target density of 1200 kg/m3, 1/3 wood-cement ratio, a dimension of 460 x 460 x 10 mm3 and 5 %, 10 %, 15 %, 20 % fly ash as cement replacement were tested for physical and mechanical properties in accordance with EN and ASTM standards. Moreover, morphological and thermal properties of the cement-bonded wood particleboards were analysed by using the scanning electron microscope and thermogravimetric analysis-derivative thermogravimetry. Test results indicated that the fly ash enhanced both the bending strength and water-resistance of the cement-bonded wood particleboards. Internal bond and screw withdrawal strengths tended to decrease as the fly ash content increased in the cement-bonded wood particleboards, but this decrease was not statistically significant. As the fly ash increased, the weight loss of the cement-bonded wood particleboards decreased in the thermogravimetric analysis because of the pozzolonic reaction of the fly ash with calcium hydroxide. In the scanning electron microscope, it was observed that calcium silicate hydrate gel increased, whereas calcium hydroxide decreased as the usage ratio of the fly ash increased in the cement-bonded wood particleboards
Chemical constituents of palm wastes slow pyrolysis derived vinegar
Get PDFOut of rachis and stem of palm tree from grooves in humid and dry zones, test materials were randomly collected and chipped for slow pyrolysis process. Chemical constituents of a set of pyrolysis derived vinegar were identified in their aqueous phase by gas chromatograph and quantitatively compared in sampled parts of sampled tree and grooves. Another set of vinegar was dewatered by dichloromethane, then their constituents were identified by gas chromatograph coupled with mass spectrometer, chemical constituents in aqueous state in both sampled grooves were the same but with different percentage values. In the organic phase, common chemical constituents of sampled parts and grooves were quantitatively compared. In humid zone rachis was 2,22 times richer in acetic acid and 2,37 times in phenol, but in dry zone stem is richer in acetic acid by 15,35 %. In their organic phases dominant and comparable chemicals of stem and rachis from sampled zone were furfural, phenol, benzic acid, 5-methyl-2- furancarboraldehyde, butanic acid and 2-methyl-phenol. Stem from dry zone was richer in these chemicals by 36,55 %, 96,93 %, 6,37 times, 62,05, 49, 32,57 % respectively. Rachis of humid zone contained more furfural, 63,95 %, 22,08 %, 2-methyl-phenol, but that of dry zone was richer in phenol by 46,20 %, 2,5 times in benzoic acid. Results from both phases of vinegar indicate that ecological impacts on the chemical constituents of palm from the same species are evident
La sostenibilidad del patrimonio urbano. Estudio de caso en Altea y La Vila Joiosa (Alicante, España)
Get PDFLos conjuntos históricos constituyen enclaves urbanos de alto interés patrimonial. Son espacios fundacionales de la ciudad destinados originalmente al hábitat. Han representado un paradigma de la noción de barrio y un referente de modelo sostenible urbano, social y económico en la cultura mediterránea europea. El fenómeno turístico puede ser una valiosa herramienta de impulso económico en esos ámbitos, pero existe el riesgo de que la sostenibilidad urbana acabe derivando en una mera explotación económica. Esta investigación realiza un estudio de caso sobre dos conjuntos históricos del levante español, representativos de la cultura urbana mediterránea, que están experimentado estos procesos, Altea y La Vila Joiosa. Se ha empleado una metodología analítica basada en indicadores multidimensionales de sostenibilidad urbana más orientados hacia lo funcional y social que a lo material. Los resultados presentan convergencias con los principales estudios del marco teórico, pero también algunos matices derivados de particularidades económicas, sociales y culturales de los conjuntos analizados en cuanto a población, vivienda y usos. Las conclusiones recalcan la importancia de asentar la imagen urbana, apoyarse en el arraigo ciudadano, evitar la privatización del espacio público y apostar por un turismo sostenible.Historical ensembles are urban areas of considerable heritage interest. They are foundational spaces of the city originally intended for habitat. They have represented a paradigm of the notion of the neighborhood, and a benchmark for a sustainable urban, social, and economic model in European Mediterranean culture. The tourism phenomenon can be a valuable tool to boost the economy in these areas, but there is a risk that urban sustainability will end up leading to mere economic exploitation. This research makes a case study on two historical ensembles of the Spanish Levante, representative of Mediterranean urban culture, which are undergoing these processes, Altea and La Vila Joiosa. An analytical methodology has been used based on multidimensional urban sustainability indicators that are more oriented towards the functional and social than the material. The results show convergences with the main studies on this theoretical framework, but also some nuances derived from the economic, social, and cultural particularities of the groups analyzed in terms of population, housing, and uses. The conclusions emphasize the importance of establishing the urban image, relying on citizen rooting, avoiding the privatization of public space, and focusing on sustainable tourism
Uso de materiales ligeros para la producción de hormigón de baja densidad: una revisión literaria
Get PDFAo longo do século XX, a indústria da construção civil vem utilizando grandes quantidades de concreto, consequentemente, a demanda por agregados naturais tem aumentado, de modo que se tornou necessário neutralizar o uso destes. Neste contexto, o presente trabalho visa apresentar uma revisão da literatura sobre o uso de materiais leves para a produção de concreto de baixa densidade com isolamento térmico produzido principalmente com agregados leves. Nesta estrutura, foram analisados 52 artigos indexados entre 2017 e 2021 no banco de dados Scopus. Os resultados revelaram que, usando ceramsite de lodo como agregado, pode-se obter uma densidade de 1251 kg/m3 e, com agregados de argila expandida, é possível obter resistências à compressão de 17,7 a 66,1 MPa. Em conclusão, determinou-se que o uso de materiais leves na produção de concreto pode reduzir sua densidade, além de contribuir para a redução dos danos ao meio ambiente.Throughout the 20th century, the construction industry has been using large quantities of concrete. Consequently, the demand for natural aggregates has increased, making it necessary to counteract their use. In this context, this work aims at presenting a literature review of the use of lightweight materials to produce low-density concrete, whose thermal insulation is mainly made using lightweight aggregates. In this framework, 52 articles indexed between 2017 and 2021 in the Scopus database were reviewed. The results revealed that, by employing ceramsite sludge as an aggregate, a density of 1,251 kg/m3 can be obtained and, with expanded clay aggregates, compressive strengths from 17.7 to 66.1 MPa can be obtained. In conclusion, it was determined that the use of lightweight materials in concrete production can reduce its density, in addition to contributing to the reduction of environmental damage.A lo largo del siglo XX la industria de la construcción viene empleando grandes cantidades de hormigón, en consecuencia, ha aumentado la demanda de los agregados naturales, de manera que se hace necesario contrarrestar el uso de estos. Frente a tal contexto, el presente trabajo tiene como objetivo presentar una revisión literaria del uso de materiales ligeros para producir hormigón de baja densidad, el cual posee aislamiento térmico que se produce principalmente con agregados ligeros. En ese marco, se revisaron 52 artículos indexados entre los años 2017 y 2021 en la base de datos de Scopus. Los resultados revelaron que, empleando ceramsite de lodo como árido, se puede obtener una densidad de 1251 kg/m3 y, con agregados de arcilla expandida, se puede obtener resistencias a la compresión desde 17.7 a 66.1 MPa. En conclusión, se logró determinar que con el uso de materiales livianos en la producción de hormigón se puede disminuir su densidad, además de contribuir en la reducción de daños que se generan al medio ambiente
Desenvolvimento da indústria siderúrgica e arquitetura de vanguarda do século XX no Chile: Unidad departamental Acería CONOX y Colada Continua (1976), e Central de Alimentación y Casino (1973) na fábrica CAP-Huachipato como exemplos do paradigma brutalista
Get PDFThe Huachipato steel plant located in San Vicente Bay, Talcahuano, was set in motion in the mid-20th century as a state initiative (personified in CORFO), to create a national production center in the Bío-Bío area and to promote economic and social development, in response to the 1930 crisis and the Chillan earthquake, in 1939. Within the first decades of operation, the Compañía de Acero del Pacífico (CAP) implemented a series of expansion plans to improve and increase production, modernizing machinery and constructing buildings to accommodate both the new industrial processes and the service equipment that the workers would use. In this context, in the 1970s, two buildings of notable architectural quality were built: the Unidad Departamental Acería CONOX y Colada Continua, and the Central de Alimentación y Casino de Trabajadores. In this study, the information available in Revista AUCA (1979), where said projects are published, was collected, and later the characteristics of these buildings were analyzed, highlighting their values as architectural work -morphological, spatial, aesthetic, structural-, reviewing the theoretical foundations and the relationship with other key architectural works, to understand the concepts of “brutalism” and “mat building”. In summary, the results reflect that these works, on adapting to functions that are so different to each other, as the industrial production and workers’ facilities) are, reflect the modern paradigm of 1959’s X CIAM and the design criteria of the architectural avant-garde of the 1960’s, becoming both industrial heritage and architectural heritage of Chile.La siderúrgica Huachipato en la bahía de San Vicente, Talcahuano, se pone en marcha a mediados del siglo XX como iniciativa estatal (personificada en CORFO) para crear un centro de producción nacional en la zona del Biobío e impulsar el desarrollo económico y social, en respuesta a la crisis de 1930 y el terremoto de Chillan ocurrido en 1939. Dentro de las primeras décadas de funcionamiento, la Compañía de Acero del Pacífico (CAP) implementó una serie de planes de expansión para mejorar y aumentar la producción, modernizando maquinarias y construyendo edificaciones a fin de dar cabida tanto a los nuevos procesos industriales, como a los equipamientos de servicios que utilizarían los obreros. En este contexto, en la década de los 70, se construyeron dos obras de notable calidad arquitectónica: la Unidad Departamental de la Acería CONOX y Colada Continua, y la Central de Alimentación y Casino de trabajadores. En el estudio que aquí se presenta, se recabó la información disponible en Revista AUCA (1979), donde dichos proyectos fueron publicados, y luego se analizaron las características de estas edificaciones poniendo en relevancia sus valores como obra de arquitectura (morfológicos, espaciales, estéticos, estructurales) y revisando los fundamentos teóricos y la relación con otras obras de arquitectura claves para entender los conceptos de “brutalismo” y “mat building”. En síntesis, los resultados reflejan que estas obras, aunque disímiles entre sí, por adaptarse a funciones tan diferentes como la producción industrial y el equipamiento para obreros, recogen el paradigma moderno del X CIAM de 1956 y los criterios proyectuales de la vanguardia arquitectónica de los años sesenta, configurándose, a la vez, como patrimonio industrial y como patrimonio arquitectónico de Chile.A usina siderúrgica Huachipato na baía de San Vicente, Talcahuano, foi lançada em meados do século 20 como uma iniciativa estatal (personificada em CORFO) para criar um centro de produção nacional na área do rio Bío-Bío e promover o desenvolvimento econômico e social como resposta à crise de 1930 e ao terremoto de Chillán, ocorrido em 1939. Nas primeiras décadas de operação, a Compañía de Acero del Pacífico (CAP) implementou uma série de planos de expansão para melhorar e aumentar a produção, modernizando máquinas e construindo edifícios para acomodar os novos processos industriais, bem como os equipamentos de serviço que os trabalhadores utilizariam. Nesse contexto, na década de 1970, foram construídas duas obras de notável qualidade arquitetônica: a Unidad departamental Acería CONOX y Colada Continua e a Central de Alimentación y Casino de trabajadores. No presente estudo foram recolhidas as informações disponíveis na Revista AUCA (1979), na qual foram publicados os respectivos projetos e, em seguida, foram analisadas as características destes edifícios, destacando os seus valores como obra de arquitetura: morfológicos, espaciais, estéticos, estruturais, revendo os fundamentos teóricos e a relação com outras obras arquitetônicas fundamentais para compreender os conceitos de "brutalismo" e "mat building". Em suma, os resultados refletem que essas obras, embora diferentes entre si, por se adaptarem a funções tão diferentes como a produção industrial e o equipamento dos trabalhadores, refletem o paradigma moderno do X CIAM de 1956 e os critérios de design da vanguarda arquitetônica dos anos sessenta, configurando-se, ao mesmo tempo, como patrimônio industrial e patrimônio arquitetônico do Chile