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1
tesis de maestría
Publicado 2024
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El emergente y exponencial crecimiento en el campo de las tecnologías avanzadas y "verdes" contribuye a un aumento global en la demanda de materias primas críticas de origen mineral, como lo son el manganeso y el cobalto. Los nódulos de manganeso han ganado reconocimiento recientemente como fuentes potenciales de estos elementos y otras materias críticas. Sin embargo, su presencia en los fondos marinos representa un dilema para los responsables políticos debido a su ubicación, con frecuencia más allá de las zonas económicas exclusivas de las naciones, y a las posibles amenazas de la minería submarina para los ecosistemas marinos abisales. La presente tesis tiene como objetivo realizar una caracterización estratigráfica, textural, mineralógica y composicional de los óxidos de Mn, incluidos los nódulos y concreciones, recubrimientos y venillas en la cuenca onshore de antearc...
2
artículo
Publicado 2019
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The behavior of the composite steel deck is conditioned, mainly, to the interaction that exists between the concrete and the steel deck, the shear connection between these two materials is provided by the mechanical adherence, which exists in its interface. In order to study these characteristics, a series of full-scale slab tests have been carried out, such as bending tests to identify the slipping load, which is directly related to the shear bond strength of the slab. The study of the shear bond strength is very important because in most cases the geometric conditions of the section and the slenderness of the slab will lead to this type of failure. For this reason, this research will be in charge of studying this failure condition, based on previously full-scale slab tests and newly constructed specimens, in order to cover as many situations as possible. The experimental results of the...
3
artículo
Publicado 2012
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The aim of the present work was to optimize the sensorial and technological features of ice cream. The experimental work was performed in two stages: 1) optimization of lactose enzymatic hydrolysis, and 2) optimization of the process and product. For the first stage a complete factorial design was developed, optimized using both response surface and the steepest ascent method. In the second stage a mixture design was performed, combining the process variables. The product with the best sensorial acceptance, high yield and low cost was selected. The acceptance of the product was developed by an untrained taster’s panel. As a main result the sensorial and technological features of the final product were improved, establishing the optimum parameters for its elaboration.
4
artículo
Publicado 2012
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The aim of the present work was to optimize the sensorial and technological features of ice cream. The experimental work was performed in two stages: 1) optimization of lactose enzymatic hydrolysis, and 2) optimization of the process and product. For the first stage a complete factorial design was developed, optimized using both response surface and the steepest ascent method. In the second stage a mixture design was performed, combining the process variables. The product with the best sensorial acceptance, high yield and low cost was selected. The acceptance of the product was developed by an untrained taster’s panel. As a main result the sensorial and technological features of the final product were improved, establishing the optimum parameters for its elaboration.
5
documento de trabajo
Publicado 2014
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Este trabajo desarrolla un modelo económico-político de equilibrio general dinámico para el tamaño y la composición óptima del gasto público. Una solución analítica es derivada de la votación por mayoría para tres categorías de gasto público: bienes de consumo público y transferencias (valorados por las familias), como también servicios públicos productivos (complementando al capital privado en una tecnología de crecimiento endógeno). La desigualdad se refleja en una distribución discreta de agentes que viven innatamente y dieren por sus tenencias de capital inicial. En contraste a la literatura previa que deriva relaciones monótonas (típicamente negativas) entre desigualdad y crecimiento en ambientes con votación unidimensional, este trabajo establece las condiciones, en un entorno de votación multidimensional, en virtud del cual una relación no monótona, forma ...
6
artículo
Publicado 2025
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Bulk-fill composite resins have emerged as a key innovation in restorative dentistry, offering an efficient and modern alternative for direct dental restorations. These resins allow for the placement of thicker layers, reducing clinical time. Among their main features are their adaptability, adequate depth of polymerization, and mechanical properties, which meet clinical requirements for functional and durable restorations. The clinical benefits of bulk-fill resins include reduced polymerization shrinkage stress and simplified handling, making them particularly useful for deep cavity restorations. However, despite these advantages, controversies have arisen regarding their long-term performance, such as color stability and wear resistance in areas of high occlusal load. This article reviews the fundamental characteristics of bulk-fill resins, their clinical benefits, and the controversie...
7
tesis de grado
Publicado 2023
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Los minerales pertenecientes al supergrupo de la turmalina son muy útiles para registrar las condiciones fisicoquímicas de su cristalización y rastrear los procesos geológicos asociados a la formación de depósitos minerales. Este estudio presenta nuevos resultados sobre la petrografía y geoquímica de turmalina en el distrito Triásico de Chacaltaya-Kellhuani-Milluni (oeste de Bolivia), ubicado en el segmento norte de la Cordillera Real dentro del Cinturón Estannífero de los Andes Centrales. El área de estudio se encuentra alrededor del stock granítico de Chacaltaya, aproximadamente 5 km al sur del granito de Huayna-Potosí. En este distrito, la mineralización hidrotermal está asociada a greisen, brechas y vetas. Se distinguen tres tipos principales de turmalina hidrotermal, de acuerdo a la petrografía: i) Tur-1, que presenta un color naranja y se manifiesta como cristales ...
8
tesis de grado
Publicado 2023
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Los minerales pertenecientes al supergrupo de la turmalina son muy útiles para registrar las condiciones fisicoquímicas de su cristalización y rastrear los procesos geológicos asociados a la formación de depósitos minerales. Este estudio presenta nuevos resultados sobre la petrografía y geoquímica de turmalina en el distrito Triásico de Chacaltaya-Kellhuani-Milluni (oeste de Bolivia), ubicado en el segmento norte de la Cordillera Real dentro del Cinturón Estannífero de los Andes Centrales. El área de estudio se encuentra alrededor del stock granítico de Chacaltaya, aproximadamente 5 km al sur del granito de Huayna-Potosí. En este distrito, la mineralización hidrotermal está asociada a greisen, brechas y vetas. Se distinguen tres tipos principales de turmalina hidrotermal, de acuerdo a la petrografía: i) Tur-1, que presenta un color naranja y se manifiesta como cristales ...
9
artículo
Publicado 2019
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In the present study, new biosorbents based on magnetite (Fe3 O4 ), hydroxyapatite (HAp) and multiple-walled carbon nanotubes (MWCNT) composites were prepared. The materials were characterized by dynamic light scattering (DLS), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), raman spectroscopy and square wave voltammetry (SWV). The synthesized magnetite presented a ferromagnetic behavior. HAp was smaller by hydrothermal synthesis. In addition, the possible use of the composite involving the 3 starting materials (Fe3O4/MWCNT/HAp) in the removal of a heavy metal such as As(V) in aqueous solution was evaluated, taking into account the influence of factors such as pH, adsorbent mass and contact time. The maximum values of percentage of removal of this metal (greater than 85 %) were obtained under conditions of pH 6, adsorbent dose of 0. ...
10
artículo
Publicado 2022
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The following study is for living knowledge about the chemical and nutritional content of maca and cañihua coming of the principal areas of production in our country, and for diffuseness of its nutritional value inside the population contributing to improve the level and quality of life of Peruvians.For this we took 25 samples of maca from the soils of Junín, Puno, Ancash y Cerro de Paseo. They were obtained at random from the cultivated fields. The circunstances of this work was when the crop of this species was carried out and taken to the regional markets.We proceed to the determination of the protein content by the method of Microkjeldhal, aminoacids content by liquid chromatography of high performance, fat, carbohydrates, ash, fiber, humidity determination according to Peruvian Thecnical norms and determination of mineral by spectrophotometric in atomic absortion.We obtained as co...
11
artículo
Publicado 2024
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Objective: This systematic review aimed to investigate the changes in the composition of the subgingival microbiota among subjects with normo-weight, overweight and obesity, in conditions of periodontal health and disease. Materials and Methods: The protocol for this study was designed following PRISMA guidelines. Records were identified using different search engines (PubMed/MedLine, Scopus and Web of Science). Observational studies, in human subjects diagnosed with obesity (BMI >30kg/m2) and periodontal disease (gingivitis and periodontitis), on the analysis of subgingival microbiota were selected. Eight articles were included. Results: The subgingival microbiota of 1,229 subjects (n=894 exposure group and n=335 control group) was analyzed. Periodontal pathogens were the most common bacteria detected in subjects with obesity and periodontitis (Porphyromonas gingivalis, Tannerella fo...
12
artículo
Publicado 2018
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The objective of this study was to determine the optimal parameters of decolorization of crude oil to obtain a semi-refined fish oil of acceptable quality; response surface methodology was used, considering a central composite design with two factors: Vacuum pressure (0.13-0.7 bar) and drying temperature (96-124°C); having as dependent variables the percentage of free fatty acids (% AGL) and color of the oil. The raw material and the optimum finished product were characterized physico-chemically, which was obtained under the operating conditions: drying temperature of 110 ° C and 0.13 bar vacuum. The finished product indicated a percentage of free fatty acids of 0.27 ± 0.01% and CieLab colour with coordinates L: 48.69 ± 0.88, a: -4.28 ± 0.26 and b: 35.03 ± 0.85, which Is equivalent to color 6 -7 in Gardner scale, compliance with the industrial specifications.
13
artículo
Publicado 2018
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The objective of this study was to determine the optimal parameters of decolorization of crude oil to obtain a semi-refined fish oil of acceptable quality; response surface methodology was used, considering a central composite design with two factors: Vacuum pressure (0.13-0.7 bar) and drying temperature (96-124°C); having as dependent variables the percentage of free fatty acids (% AGL) and color of the oil. The raw material and the optimum finished product were characterized physico-chemically, which was obtained under the operating conditions: drying temperature of 110 ° C and 0.13 bar vacuum. The finished product indicated a percentage of free fatty acids of 0.27 ± 0.01% and CieLab colour with coordinates L: 48.69 ± 0.88, a: -4.28 ± 0.26 and b: 35.03 ± 0.85, which Is equivalent to color 6 -7 in Gardner scale, compliance with the industrial specifications.
14
artículo
Publicado 2018
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The objective of this study was to determine the optimal parameters of decolorization of crude oil to obtain a semi-refined fish oil of acceptable quality; response surface methodology was used, considering a central composite design with two factors: Vacuum pressure (0.13-0.7 bar) and drying temperature (96-124°C); having as dependent variables the percentage of free fatty acids (% AGL) and color of the oil. The raw material and the optimum finished product were characterized physico-chemically, which was obtained under the operating conditions: drying temperature of 110 ° C and 0.13 bar vacuum. The finished product indicated a percentage of free fatty acids of 0.27 ± 0.01% and CieLab colour with coordinates L: 48.69 ± 0.88, a: -4.28 ± 0.26 and b: 35.03 ± 0.85, which Is equivalent to color 6 -7 in Gardner scale, compliance with the industrial specifications.
15
artículo
Publicado 2018
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The objective of this study was to determine the optimal parameters of decolorization of crude oil to obtain a semi-refined fish oil of acceptable quality; response surface methodology was used, considering a central composite design with two factors: Vacuum pressure (0.13-0.7 bar) and drying temperature (96-124°C); having as dependent variables the percentage of free fatty acids (% AGL) and color of the oil. The raw material and the optimum finished product were characterized physico-chemically, which was obtained under the operating conditions: drying temperature of 110 ° C and 0.13 bar vacuum. The finished product indicated a percentage of free fatty acids of 0.27 ± 0.01% and CieLab colour with coordinates L: 48.69 ± 0.88, a: -4.28 ± 0.26 and b: 35.03 ± 0.85, which Is equivalent to color 6 -7 in Gardner scale, compliance with the industrial specifications.
16
artículo
Publicado 2017
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Microbial proteases are the most important group in the enzymes world market, because have several industrial applications. Moreover, they have some advantages respect to proteases produced by other sources, such as to have more stability and to be excreted to fermentation medium. The genus Pseudomonas has been studied as a protease producer of enzymes with industrial potential. Nevertheless, the production is affected by factors such as medium composition and culture conditions, and their optimization lead to reduce costs and increase yield. In this context, medium components that influenced significantly in production of Pseudomonas sp. M211 extracellular proteases in submerged fermentation were determined. In this work, one-factor-at-a-time method was used to assess the effect of different carbon, nitrogen and ions sources in proteases production. The highest level of extracellular pr...
17
artículo
Publicado 2021
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In Peru the COVID-19 pandemic led to a strict quarantine since March 15th, in the city of Arequipa this situation prevailed until September 17th when measures were slowly loosen up. This state of emergency has produced a series of environmental changes on water and air quality and also changes in waste generation and composition, however the latter data has not been equally collected and disseminated. This case study presents the results of waste characterization from 25 households in 8 districts in the province of Arequipa. The Technical Team of Solid Waste form the Environmental Engineering Faculty of the National University of Engineering conducted the study. Data from waste generation and segregation habits was gathered and, after receiving the appropriate training, participants provided information about their household waste generation and composition (between the 1st and 7th of Se...
18
artículo
Publicado 2012
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Objective: to compare in vitro the marginal seal degree of composite resin restorations photopolomerized with L.E.D light and conventional halogen light, was the objective of this research.It was used 20 healthy molars recently extracted, in each of them, standardized dimensions class V cavities were prepared in the buccal and palatal aspects. Both cavities were filled with nanoparticles composite resin, Filteck Z350 and Single Bond adhesive (3M). Vestibular restaurations were light cured using L.E.D light, and palatal with conventional halogen light. Once restored, the molars were maintained for 48 hours at 37 °C and 100 % humidity. Samples were subjected to 1 % blue methylene solution thermocycling regimen, and then the marginal leakage degree was assessed, making a palatal-vestibule coronal cut, and the evaluation with a stereoscopic microscopy. The frequency of specimens that leakag...
19
artículo
Publicado 2012
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Objective: to compare in vitro the marginal seal degree of composite resin restorations photopolomerized with L.E.D light and conventional halogen light, was the objective of this research.It was used 20 healthy molars recently extracted, in each of them, standardized dimensions class V cavities were prepared in the buccal and palatal aspects. Both cavities were filled with nanoparticles composite resin, Filteck Z350 and Single Bond adhesive (3M). Vestibular restaurations were light cured using L.E.D light, and palatal with conventional halogen light. Once restored, the molars were maintained for 48 hours at 37 °C and 100 % humidity. Samples were subjected to 1 % blue methylene solution thermocycling regimen, and then the marginal leakage degree was assessed, making a palatal-vestibule coronal cut, and the evaluation with a stereoscopic microscopy. The frequency of specimens that leakag...
20
tesis de maestría
Publicado 2017
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En la presente tesis, se estudió la influencia de la anisotropía y la humedad en las propiedades mecánicas a la tracción y la resistividad volumétrica de los compuestos de Acrilonitrilo Butadieno Estireno reforzado con Nano Tubos de Carbono y Acrilonitrilo Butadieno Estireno reforzado con Micro Fibras de Carbono impresos en 3D de por Deposición de Material Fundido. Para estudiar la influencia de la anisotropía, tres diferentes orientaciones de impresión de capa fueron comparadas (0°, 45° and 45°/-45°) esto para una altura de capa de 0.2 mm. Se concluyó que la influencia de la anisotropía es importante para el comportamiento mecánico de el Acrilonitrilo Butadieno Estireno con Micro Fibras de Carbono esto debido a la relación que existe entre la resistencia que realiza el refuerzo y el alineamiento que presentan las fibras respecto a la dirección de tracción. Por otro lad...
