Influence of Manufacturing Parameters and Post Processing on the Electrical Conductivity of Extrusion-Based 3D Printed Nanocomposite Parts

The influence of manufacturing parameters of filament extrusion and extrusion-based Additive Manufacturing (AM), as well as different post processing techniques, on the electrical conductivity of 3D printed parts of graphene nanoplatelets (GNP)-reinforced acrylonitrile butadiene styrene (ABS) has been analyzed. The key role of the manufacturing parameters to obtain electrically conductive filaments and 3D printed parts has been demonstrated. Results have shown that an increase in extrusion speed, as well as lower land lengths, induces higher extrudate swelling, with the consequent reduction of the electrical conductivity. Additionally, filaments with lower diameter values, which result in a higher surface-to-cross-section ratio, have considerably lower electrical conductivities. These factors tune the values of the volume and surface electrical conductivity between 10-4-100 S/m and 10-8-10-3 S/sq, respectively. The volume and surface electrical conductivity considerably diminished after 3D printing. They increased when using higher printing layer thickness and width and were ranging between 10-7-10-4 S/m and 10-8-10-5 S/sq, respectively. This is attributed to the higher cross section area of the individual printed lines. The effect of different post processing (acetone vapor polishing, plasma and neosanding, which is a novel finishing process) on 3D printed parts in morphology and surface electrical conductivity was also analyzed

Deregulating the electricity sector

The purpose of this paper is to review several ways of restructuring the industrial electric sector providing examples of countries which have adopted the models that are submitted and that will be turning up in this work. The alternatives for a wholesale electricity market organisation are displayed taking into account that each particular solution to be adopted depends on the case of study features. In addition, advice is given on the transmission and distribution business regulation problem. Finally, we analyse the deregulation of the electricity sector in Uruguay in relation with the particular characteristics of the Uruguayan market

Mebendazole spectrophotometric determination: theorical and experimental study of the interaction with sodium hydroxide

USP, EP, and Argentinian Pharmacopoeia proposed HPLC-UV for quantitative quality control of mebendazole (MBZ) tablets. In this work, a spectrophotometric method is proposed. A mebendazole solution was prepared by dissolving the active ingredient in an ethanolic solution of HCl (1: 100) and adding NaOH 3N. It was allowed to stand 10 minutes. Absorbance spectrum was scanned between 350 and 700 nm. Maximum was found at 400 nm. A calibration curve in the range of 0.05 to 0.25 mg / mL, responded to A = (2.2746 ± 0.0224) C + (0.0012 ± 0.0068) with R2 = 0.9999. The RSD% was 0.961 indicating good repeatability for the analytical procedure. Accuracy in recovery experience was found to be 99.2 - 100.6%. Statistical comparison using t -test and F ?test indicate that there are no significant differences between HPLC and the spectrophometric methods, whith a 95% confidence level. Specificity and intermediate precision assays were satisfactory. Quantum theoretical chemistry was applied to elucidate the interaction that gives origin to the color, using static approximation and density functional theory, B3LYP and base 6-311G (d, p). Excitation energies B3LYP for MBZ and MBZ product of the interaction with sodium atom, were coincidental with experimental results.Fil: Delfino, Mario Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; ArgentinaFil: Monzón, Celina María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; ArgentinaFil: Jorge, Nelly Lidia. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Sarno, María del Carmen Teresa. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; Argentin

Fast and Efficient Monitoring of Diclofenac Dissolution Profile by CE

Capillary electrophoresis (CE) was used to follow Diclofenac tablet dissolution, in very short times and allowing dissolution testing without volume replacement. By using Student´s t test and F-test, this CE method was compared with HPLC. Statistical data show that there are no significant differences among them. The drug release kinetic of diclofenac tablets was described by various mathematical models and equations. Model-Independent Methods: t50% = 10.34 min; t80% = 20 min; DE% = 79.41% and MDT = 10.85 min, show that diclofenac tablet dissolution rate is very high, having 80% drug dissolution within 20 minutes. Model-Dependent Methods. The kinetics models used were: zero order, first order, Hixson?Crowell cube root law, Higuchi model, and Weibull model. Criteria used to choose the best model was by comparisson of r2 and AIC (Akaike Information Criteria). The model that best adjusts diclofenac tablet dissolution profile was the Hixson-Crowell cube root model.Fil: Monzón, Celina María. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Vera Candioti, Luciana. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Química. Cátedra de Química Analítica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Sarno, María del Carmen Teresa. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Delfino, Mario Raul. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

Calidad de suministro eléctrico : huecos de tensión. Mitigación de sus efectos en las plantas industriales

El objetivo principal de este proyecto se centra en el estudio y caracterización de los huecos de tensión, cómo se originan y el impacto en los consumidores, en particular en los industriales. Se detallarán otras perturbaciones con el fin de conocer el ámbito de la calidad de suministro. Se facilitará el estudio del impacto económico, y el coste de su mitigación, que tienen los huecos de tensión en la industria estableciendo una serie de protocolos que permitan el análisis de inversión de forma individualizada para cada caso.Ingeniería Técnica en Electricida

diseño de investigación para el análisis del efecto de las pérdidas en la red eléctrica de Guatemala de las centrales de generación renovable y no renovable con base en su ubicación topológica para el período 2017-2021.

Analiza las pérdidas de energía en la red eléctrica de Guatemala provocadas por la distancia entre los usuarios y los generadores renovables y no renovables de energía eléctrica

Biodegradable polymer compounds reinforced with banana fiber for the production of protective bags for banana fruits in the context of circular economy

Bags used to protect and accelerate the ripening of bananas are a clear example of the environmental problem of packaging waste. Small pieces of these non-biodegradable bags are frequently disposed on the soil by accident (environmental conditions and poor handling during the harvest) and remain there for years. This work focuses on the development of protective biodegradable bags reinforced with banana fiber, obtained from waste of the banana plants, thus promoting a circular economy and a more environmentally friendly process. To achieve this, different bio-based composites were tested (processability) by compounding extrusion (biopolymer and banana fiber with different process steps) and blown film extrusion. The bags produced were tested in field and sequentially improved in three generations of biofilms. The results showed that the maximum processable fiber content was 5 wt %. Additionally, the micronizing of the compounds was crucial to simplify the blown film extrusion and improve the smoothness of the bags (scratches avoidance on the banana surface). The final bags (Mater-Bi biopolymer, 5% combed and sieved banana fiber, and 2.5 wt % TiO2 for ultraviolet light filtration), performed better than the conventional ones (faster maturing, i.e., earlier harvest, and easier handling) and fulfilled the biodegradability, composting and ecotoxicity test requirements

Analysis of processing and environmental impact of polymer compounds reinforced with banana fiber in an injection molding process

The global consumption of thermoplastic materials of fossil origin continues to grow, generating high environmental impacts mainly due to the energy consumed during their production and processing. The use of natural materials, such as banana fiber (BF), present a sustainable alternative for the gradual replacement of these thermoplastic materials, potentially reducing the environmental impact and improving their mechanical performance. This work presents the development of HDPE compounds reinforced with BF for injection molding of components with lower environmental impact. To this end, the processing and treatment of the banana pseudostem fiber have been analyzed, and compounds with fiber percentages of up to 20 wt %, with and without chemical treatment, have been developed and characterized thermal and mechanically. Finally, thickness optimizations of a case study component have been carried out through finite element simulation, with fiber percentages up to 30 wt %, maintaining the stiffness of the original HDPE component. A Life Cycle Assessment was also carried out to assess the influence of the different processing scenarios. The results showed, on the one hand, that the fibers without chemical treatment and with mechanical combing allow improvements in the mechanical properties of HDPE compounds similar to those obtained with chemically treated fibers but considerably reducing the impacts due to the suppression of the fiber treatment (chemical products, subsequent drying, etc.). On the other hand, the environmental impact analysis showed that compounds with percentages of untreated fiber greater than 20 wt % reduce the impact of the components produced compared to pure HDPE. Finally, the incorporation of the BF also allowed the design optimization of the study component, reducing its thickness but maintaining the same original stiffness, further improving its environmental impact

La economía social en clave internacional. Cuantificación, reconocimiento institucional y visibilidad social en Europa, Iberoamérica y Norte de Africa

El presente trabajo tiene tres mayores objetivos: en primer lugar, pretende analizar el grado de visibilidad social del concepto de economía social desde una perspectiva internacional, entendiendo por ello su grado de conocimiento y percepción por la sociedad. En segundo lugar, estudiar su grado de institucionalización en el ordenamiento jurídico ya sea con leyes, políticas de fomento o con órganos específicos de atención a la economía social. Finalmente, pretende cartografiar cuantitativamente la economía social, trazando las dimensiones macroeconómicas de este tercer sector de las economías. El ámbito geográfico abordado son los países de la Unión Europea, Iberoamérica y Norte de África. Se parte de la concepción de economía social acuñada en la literatura científica y recientemente sancionada en la nueva legislación en la materia