Repositorio institucional - Concytec
Not a member yet
3190 research outputs found
Sort by
Development of an object-oriented programming tool based on fem for numerical simulation of mineral-slurry transport
No full textThe early stages of the development of a finite element method (FEM) based computational tool for numerically simulating mineral-slurry transport involving both Newtonian and non-Newtonian flows are described in this work. The rationale behind the conception, design and implementation of the referred object-oriented programming tool is thus initially highlighted. A particular emphasis is put on several architectural aspects accounted for and object class hierarchies defined during the development of the tool. Next one of the main modules composing the tool under development is further described. Finally, as a means of illustration, the use of the FEM based tool for simulating two-dimensional laminar flows is discussed. More specifically, canonical configurations widely studied in the past are firstly accounted for. A more practical application involving the simulation of a mineral-slurry handling device is then studied using the power-law rheological model. The results from the simulations carried out highlight the usefulness of the tool for realistically predicting the associated flow behavior. The FEM based tool discussed in this work will be used in future for carrying out high-fidelity numerical simulations of turbulent multiphase flows including fluid-particle interactions. © Springer Nature Switzerland AG 2020.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Fabrication and thermomechanical evaluation in controlled atmospheres of SiC/Si biomorphic compounds
No full textBiomorphic SiC/Si compounds were fabricated from copaiba wood (Copaifera officinalis, natural wood native to Peru), by reactive infiltration of molten silicon in a porous carbon preform obtained by a controlled pyrolysis process of wood. Structural and microstructural characterization tests by X-ray diffraction and scanning electron microscopy, respectively, revealed, on the one hand, the presence of crystalline phases of SiC, Si and C, and on the other, the typical morphology of this type of material, which it consists of a continuous SiC scaffold with elongated channels in the direction of tree growth and the presence of residual Si and C located mainly in the porosities of the material. The mechanical behavior in uniaxial compression was also studied at a constant compression rate of 0.05 mm/min and as a function of temperature (from ambient to 1400 ºC) and test atmosphere (ambient air, humid air, dry air, Ar, N2 and reducing mixture (95% Ar + 5% H2). The mechanical results were evaluated based on values of maximum stress and modulus of elasticity (stiffness), finding a clear reduction in the values of maximum stress and stiffness of the material when the samples passed of ambient test temperatures at 1400 ºC. On the other hand, mechanical tests in a controlled atmosphere were carried out at a constant temperature of 1100 ºC and the results showed that the mechanical behavior of the studied compounds is slightly influenced by the working atmosphere. Mechanical data found in the various test conditions will be an important support for the definition of the maximum allowable stress (considering the safety factor applied for a particular case) in the industrial application of the materials studied in this work. © 2020, Avestia Publishing. All rights reserved.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Amyloid beta oligomers: how pH influences over trimer and pentamer structures?
No full textThe aggregation of proteins in the brain is one of the main features of neurodegenerative diseases. In Alzheimer’s disease, the abnormal aggregation of A?-42 is due to intrinsic and extrinsic factors. The latter is due to variations in the environment, such as temperature, salt concentration, and pH. We evaluated the effect of protonation/deprotonation of residues that are part of trimeric and pentameric oligomers at pH 5, pH 6, and pH 7. Molecular dynamics simulation at 200 ns in the canonical ensemble was implemented. The results have revealed that histidine, glutamic acid, and aspartic acid residues showed a protonation/deprotonation effect in oligomers. The root mean square deviation analysis was used to analyze the structural stability at different pHs. We found an increase in hydrophobicity in the side chains of the trimer, while in the pentamer, the structural instability of a compact structure at pH 5 caused the hydrophobic core to open, revealing the hydrophobic region to the environment. At this point, we believe that conformational changes mediated by pH are essential in the aggregation of A?-42 oligomers. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Compact and unified elasto-plastic formulation to study isotropic plates
No full textWe introduce a compact and unified shear deformation theory for plates with elasto-plastic behavior. We formulate the kinematics of the two-dimensional structure in a compact and unified manner using the Carrera Unified Formulation. This formulation allows for generalized expansions of the primary variables and through-the-thickness functions. We obtain the governing equations using the principle of virtual work and a finite element discretization. We solve the nonlinear equations using a Newton–Raphson linearization scheme, and linearize the constitutive equations using the algorithmic tangent moduli. We consider the J2 flow theory of plasticity, and use a backwards Euler scheme to update the stresses. We analyze the convergence, and compare the effectiveness of the Mixed Interpolation of Tensorial Components technique in contrasting the shear locking phenomenon in the nonlinear regime to the use of full and uniform reduced integration. We also conduct numerical assessments for plates under uniform and line loads. We compare the present results to those obtained by finite element commercial software, and demonstrate the computational efficiency of the present method. © 2019Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Use of magnetic particles in the purification of igm antibodies against taenia solium
No full textThe use of L protein coupled magnetic particles for the concentration and purification of immunoglobulin M (mIgM) monoclonal antibodies against Taenia solium was evaluated. Three concentration methods and different elution times were evaluated and the ratio of particles to the ratio of mIgM was optimized. It is demonstrated that: 1) with the use of magnetic particles, a previous concentration of mIgM is not required, which reduces the manipulation of the antibodies and improves the recovery, 2) the use of a binding buffer can be omitted, since the pH of most cell culture supernatants are neutral, and 3) longer elution times (~ 45 minutes) are needed to increase recovery to a level greater than 80%. The study demonstrates that the use of L protein-coupled magnetic particles is a simple and efficient tool for mIgM concentration and purification. © 2020, Instituto Nacional de Salud. All rights reserved.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Schizaraeus fouquei sp. nov., the first record of schizaraeus from Peru (Coleoptera: Tenebrionidae: Stenosini)
No full textA new species of Stenosini (Coleoptera: Tenebrionidae: Pimeliinae), Schizaraeus fouquei sp. nov. is described from southern Andes of Peru: Apurímac and Cusco regions. Prior to this study, Schizaraeus Kulzer, 1955 was monotypic with one species, S. acuticosta Kulzer, 1955 from Catamarca Province in Argentina. We present habitus photographs of both species, scanning electron micrographs of external morphology of the new species, a distribution map, and a comparison of the characters of both species of the genus. © 2020 The Authors.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Six hundred years of South American tree rings reveal an increase in severe hydroclimatic events since mid-20th century
No full textSouth American (SA) societies are highly vulnerable to droughts and pluvials, but lack of long-term climate observations severely limits our understanding of the global processes driving climatic variability in the region. The number and quality of SA climate-sensitive tree ring chronologies have significantly increased in recent decades, now providing a robust network of 286 records for characterizing hydroclimate variability since 1400 CE. We combine this network with a self-calibrated Palmer Drought Severity Index (scPDSI) dataset to derive the South American Drought Atlas (SADA) over the continent south of 12 degrees S. The gridded annual reconstruction of austral summer scPDSI is the most spatially complete estimate of SA hydroclimate to date, and well matches past historical dry/wet events. Relating the SADA to the Australia-New Zealand Drought Atlas, sea surface temperatures and atmospheric pressure fields, we determine that the El Nino-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) are strongly associated with spatially extended droughts and pluvials over the SADA domain during the past several centuries. SADA also exhibits more extended severe droughts and extreme pluvials since the mid-20th century. Extensive droughts are consistent with the observed 20th-century trend toward positive SAM anomalies concomitant with the weakening of midlatitude Westerlies, while low-level moisture transport intensified by global warming has favored extreme rainfall across the subtropics. The SADA thus provides a long-term context for observed hydroclimatic changes and for 21st-century Intergovernmental Panel on Climate Change (IPCC) projections that suggest SA will experience more frequent/severe droughts and rainfall events as a consequence of increasing greenhouse gas emissions.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Regenerative potential of allogeneic adipose tissue-derived mesenchymal cells in canine cutaneous wounds
No full textBackgroundMesenchymal stem cells (MSCs) have generated a great amount of interest over the past decade as a novel therapeutic treatment for a variety of diseases. Emerging studies have indicated that MSCs could enhance the repair of injured skin in canine cutaneous wounds.Case presentationA healthy 2 years old Bodeguero Andaluz dog was presented with multiple skin bite wounds. Antibiotic and anti-inflammatory therapy was administered for 8 days. On day three, 10(7) allogeneic adipose-derived mesenchymal stem cells (ASCs) were intradermally injected approximately equidistant to the ASCs treated wounds. Control wounds underwent conventional treatment with a topical antibacterial ointment until wound healing and closure. Wounds, skin morphology and healing progress were monitored via serial photographs and histopathology of biopsies obtained at day seven after ASC treatment. Histopathology revealed absence of inflammatory infiltrates and presence of multiple hair follicles in contrast to the non-ASCs treated control wounds indicating that ASC treatment promoted epidermal and dermal regeneration. ASCs were identified by flow cytometry and RT-PCR. The immunomodulatory role of ASCs was evidenced by coculturing peripheral blood mononuclear cells with allogeneic ASCs. Phytohemagglutinin was administered to stimulate lymphocyte proliferation. Cells were harvested and stained with an anticanine CD3-FITC antibody. The ASCs inhibited proliferation of T lymphocytes, which was quantified by reduction of carboxyfluorescein succinimidyl ester intensity using flow cytometry.ConclusionsCompared with conventional treatment, wounds treated with ASCs showed a higher regenerative capacity with earlier and faster closure in this dog.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Towards urban archaeo-geophysics in peru. The case study of plaza de armas in cusco
No full textFunding: The paper shows the results of the research project “Prospección geofísica para determinar las Funding: “The paper shows the results of the research project “Prospección geofísica para determinar las Universidad Nacional de San Antonio Abad del Cusco funded by UNSAAC Framework agreement between posibles estructuras soterradas en la plaza de armas del cusco utilizando un radar de penetración terrestre” of CONCYTEC-UNSAAC-FONDECYT. The research was co-funded by CNR with funds of Joint Laboratory of Universidad Nacional de San Antonio Abad del Cusco funded by UNSAAC Framework agreement between CONCYTEC-UNSAAC - FONDECYT. The research was co-funded by CNR with funds of Joint Laboratory of Acknowledgments: We acknowledge the archaeologist Angel Sanchez for his support during the Pre-hispanic Archaeological Science (LaPAS). geophysical prospections. Acknowledgments: We acknowledge the archaeologist Angel Sanchez for his support during the geophysical study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.Menciona que uno de los desafíos más complejos de las ciencias del patrimonio es la identificación y protección del patrimonio arqueológico enterrado en áreas urbanas y la necesidad de gestionar, mantener e inspeccionar servicios subterraneos. La arqueología y la geofísica, utilizadas de forma integrada, proporcionan un importante contribución para abrir nuevas perspectivas en la comprensión tanto de la historia de las ciudades como para ayudar a la tomadores de decisiones en la planificación y gobernanza del desarrollo y la gestión urbanos. Los problemas de identificación e interpretación de características geofísicas en el subsuelo urbano hacen necesario Desarrollar procedimientos ad hoc para ser implementados y validados en estudios de casos significativos. Este papel trata los resultados de un proyecto interdisciplinario en Cusco (Perú), la capital del Imperio Inca, donde se aplicó por primera vez el método georadar en la plaza principal. El método de georadar fue empleado con éxito basado en el conocimiento de la evolución histórica del Cusco y la disponibilidad de registros arqueológicos proporcionados por algunas excavaciones cercanas al área de estudio. Partiendo de un modelo para la reflexión de ondas electromagnéticas de estructuras arqueológicas y tuberías, resultados de georadar fueron interpretados mediante análisis morfológico comparativo de los valores de alta amplitud observados a partir de segmentos de tiempo con reflectores visualizados en los radargramas.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Comportamiento reológico y propiedades funcionales de chocolates oscuros con incorporación de arazá (Eugenia stipitata)
No full textLa tendencia en la fabricación de alimentos se inclina hacia el consumo de alimentos funcionales. Se ha demostrado que los chocolates poseen propiedades funcionales que son otorgadas por los granos de cacao del cual están hechos. En el presente estudio se evaluó el comportamiento reológico, propiedades funcionales y sensoriales de chocolates oscuros elaborados con granos de cacao criollo e incorporación de pulpa liofilizada de arazá (PLA) en diferentes porcentajes (1; 1,5 y 2%). No hubo cambios significativos en la textura de chocolate testigo y los tratamientos. El rendimiento de Casson aumentó a medida que se incrementó el porcentaje de PLA y sucedió lo contrario con la viscosidad plástica de Casson. Las propiedades funcionales de los chocolates mostraron un contenido fenólico total (CFT) entre 13,52 ± 1,90 y 18,73 ± 0,72 y actividad antioxidante entre 0,005 ± 0,004 y 0,010 ± 0,003, medidos como IC50. En el análisis sensorial, los tratamientos y testigo mostraron una puntuación de 7 en escala hedónica (me gusta moderadamente). Se demostró que, a las concentraciones de PLA utilizadas en la formulación de los chocolates oscuros, no se mejoran las propiedades funcionales del producto final.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy