Se investigó el efecto de la adición de polietileno maleatado en compuestos de etilen vinil acetato reforzados con harina de Telinne Monspessulana previamente mercerizada. Dos factores fueron analizados: (i) concentración del agente de acoplamiento con cinco niveles 2, 4, 6, 8, 10 partes por cien de polímero; y (ii) concentración de harina con dos niveles: 25 y 40 partes por cien de polímero. El efecto del polietileno maleatado sobre la compatibilidad entre etilen vinil acetato y la harina vegetal fue evaluado a través de ensayos de tensión a los compuestos. Los análisis permiten establecer que el agente de acoplamiento tipo polietileno maleatado mejoró la compatibilidad de los compuestos, efecto que fue evidenciado en los valores del módulo de Young y la resistencia a la tracción. Con base en estos resultados se concluye que el polietileno maleatado es una alternativa como agente de acoplamiento en compuestos de etilen vinil acetato y fibras naturales.
En el presente trabajo se presenta una nuevo algoritmo para encontrar la envolvente convexa C(P) para un conjuntos P de n puntos en R 2. Este problema ha sido ampliamente estudiado en la geometría computacional ya que tiene importante aplicaciones en la ingeniera y otros campos del conocimiento. El algoritmo propuesto se basada en búsquedas direccionales de hiperplanos soporte y una variante que incorpora hiperplanos separadores que permiten reducir el número de puntos evaluados, descartando los que son interiores. La aplicación del algoritmo propuesto se ilustra mediante un ejemplo. La complejidad del algoritmo obtenido es O(máx (nvo; nv o)), vo ≤ v ≤ n y v o ≤ v ≤ n, donde v es el número de vértices de la envolvente convexa.
PurposeThe aim of this research is to improve the responsiveness of the healthcare network of a large city to a major earthquake, by applying a combined methodology to reduce human suffering and death.Design/methodology/approachScenario analysis, a non-linear programming (NLP) model, and the analytical network process are sequentially applied to find the “best location pattern”.FindingsWhen considering the occurrence of major earthquakes in cities with high population density, as a rule of thumb, the location of healthcare facilities should prioritize areas characteristically overcrowded and/or that were built based on poor standards of seismic resistance.Research limitations/implicationsThe proposed research design does not include a cost criterion in the set of decision variables involved. Furthermore, the results derived from the NLP-model are restricted by the input simulation data.Practical implicationsThe performance of the “best location pattern” is compared with the current location of healthcare facilities in terms of their distances to the affected zones. Metropolis areas worldwide with similar conditions to the city under consideration could be benefited from applying the general methodology for relocation of healthcare facilities described in this research.Originality/valueThis research implements a diverse combination of methodologies to examine the problem of relocating of healthcare facilities in a large city in the wake of an assumed earthquake. In addition, to the best of authors' knowledge, this is the first study of its kind that proposes improvements in the responsiveness of the healthcare facilities' network in the city in question.
Linear programming (LP) is one of the most widely-applied techniques in operations research. Many methods have been developed and several others are being proposed for solving LP problems, including the famous simplex method and interior point algorithms. This study was aimed at introducing a new method for solving LP problems. The proposed algorithm starts from an interior point and then carries out orthogonal projections using parametric straight lines to move between the interior and polyhedron frontier defining the feasible region until reaching the extreme optimal point.
ResumenSe realizó un estudio experimental para medir la fuerza adhesiva de dos láminas de composición similar unidas con adhesivo. Las láminas se fabricaron a partir de polietileno con 32% de harina Telinne monspessulana y 5,2% de polietileno maleatado. Se usaron dos tipos de adhesivos ecológicos: poliuretano en dispersión acuosa y goma caliente de etilen vinil acetato (hot melt). Los substratos o superficies a unir de cada lámina previamente fueron sometidos a abrasión mecánica. Posteriormente las superficies fueron tratadas por separado con silano vinil-tri(2-metoxi etoxi), primer acrílico y diisocianato. La resistencia a la separación de ambos substratos denominada fuerza adhesiva de la junta, fue determinada aplicando la prueba 180º T-peel adhesión. Los tratamientos químicos aumentaron la resistencia adhesiva de las juntas unidas con poliuretano, los valores más altos se obtuvieron al unir los substratos con adhesivo hot melt sin tratamiento químico. La adición de agente maleatado en el compuesto de madera plástica no mejoró la eficiencia de los tratamientos químicos.Palabras clave: madera plástica; junta adhesiva; polietileno de baja densidad; peel adhesión; primer, adhesivo. Analysis of Bonded Joints Made with (Wood Plastic Composite Sheet) / (Ecological Adhesive) / (Wood Plastic Composite Sheet) AbstractAn experimental study was performed to measure the resistance to adhesive peel strength of two sheets of similar composition bonded with adhesive. The sheets were made from polyethylene with 32% Telinne monspessulana flour and 5.2% maleated polyethylene. Two types of eco-friendly adhesives were used: aqueous dispersion polyurethane and hot melt ethylene vinyl acetate base. The substrates or surfaces to be bonded from each sheet previously were subjected to mechanical abrasion. Subsequently the surface was treated with vinyl tri (2 -methoxyethoxy) silane, acrylic and diisocyanate primers. The resistance to the separation of both substrates also named as adhesive force of the joint, was determined with the test 180º T-peel adhesión. Chemical treatments increased the peeling strength in the bonded joints with polyurethane water-based, however higher values were obtained by joining the substrates with hot melt adhesive without chemical treatment. The addition of maleate in the wood plastic composite did not improve the efficiency of chemical treatments.
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