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oxidation processes » operational processes (Expander búsqueda), production processes (Expander búsqueda)
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oxidation processes » operational processes (Expander búsqueda), production processes (Expander búsqueda)
data oxidation » wet oxidation (Expander búsqueda), ala oxidacion (Expander búsqueda), auto oxidation (Expander búsqueda)
1
artículo
Arsenate As(V) is a toxic contaminant commonly found in aquifers and groundwater that poses significant risks to human health. The effective treatment of arseniccontaminated water is therefore crucial for safeguarding public health. This study investigates removing As(V) using iron oxide-coated ignimbrite in batch experiments by varying the adsorbent dosage, initial As(V) concentration, contact time, and system temperature. The adsorption experiments revealed that the Langmuir isotherm model better fit the data (R2 = 0.99) than the Freundlich model (R2 = 0.73). According to the Langmuir model, the maximum adsorption capacity of As(V) on the iron oxide-coated ignimbrite was 4.84 mg·g −1 ± 0.12 mg·g −1 of As(V), with a standard deviation of ±0.05 mg·g −1 after 2 h of exposure with 0.15 g/50 mL iron oxide-coated ignimbrite adsorbent concentration. In the kinetic analysis, the pse...
2
artículo
Publicado 2019
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AP is supported by the “ Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica ” (Fondecyt - Peru), through the MAGNET research program. The collection of sampling was carried out within the framework of the “Impacto de la Variabilidad y Cambio Climático en el Ecosistema de Manglares de Tumbes” project. Supported by the International Development Research Centre of Canada under management of the Instituto Geofísico del Perú (IGP). WM is supported by research grants from the Brazilian Research Council (CNPq) . CJS is supported by the Australian Research Council ( DE160100443 , DP150103286 and LE140100083 ), in cooperation with Universidade Federal Fluminense . Project CTQ2011-28079-CO3-02 which is also supported with ERDF . We would like to thank Kelly Ronchi for the language revision.
3
artículo
Publicado 2020
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Magma recharge into a differentiated reservoir is one of the main triggering mechanisms for explosive eruptions. Here we describe the petrology of the eruptive products of the last explosive eruption of Tutupaca volcano (southern Peru) in order to constrain the pre-eruptive physical conditions (P-T-XH2O) of the Tutupaca dacitic reservoir. We demonstrate that prior to the paroxysm, magma in the Tutupaca dacitic reservoir was at low temperature and high viscosity (735 ± 23 °C), with a mineral assemblage of plagioclase, low-Al amphibole, biotite, titanite, and Fe-Ti oxides, located at 8.8 ± 1.6 km depth (233 ± 43 MPa). The phenocrysts of the Tutupaca dacites show frequent disequilibrium textures such as reverse zonation, resorption zones, and overgrowth rims. These disequilibrium textures suggest a heating process induced by the recharge of a hotter magma into the dacitic re...
4
artículo
Publicado 2016
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In the Do Azul mine, the manganese pisoliths are scattered in irregular layers of lateritic rocks, which form small hills, covering the slopes and surfaces with colluvial materials from the Igarapé Do Azul plateau. They are packages that reach up to 8 meters thick and are of great importance for understanding the processes of formation of manganese superegenous deposits. The pisoliths have spherical, sub-spherical and also angular shapes, the size of their diameters varies from 0.5 to 8 mm and are normally made up of a nucleus, surrounded by concentric layers. For the most part, the cores and layers are well differentiated. The nuclei can occupy from 10 to 80% of the total volume of each pisolite and are mainly made up of Mn oxides and hydroxides such as: cryptomelan, pyrolusite, lithophorite, hollandite, todorokite and birnessite, also occurring gibbsite, kaolinite and anatase in varia...
5
artículo
Publicado 2016
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In the Do Azul mine, the manganese pisoliths are scattered in irregular layers of lateritic rocks, which form small hills, covering the slopes and surfaces with colluvial materials from the Igarapé Do Azul plateau. They are packages that reach up to 8 meters thick and are of great importance for understanding the processes of formation of manganese superegenous deposits. The pisoliths have spherical, sub-spherical and also angular shapes, the size of their diameters varies from 0.5 to 8 mm and are normally made up of a nucleus, surrounded by concentric layers. For the most part, the cores and layers are well differentiated. The nuclei can occupy from 10 to 80% of the total volume of each pisolite and are mainly made up of Mn oxides and hydroxides such as: cryptomelan, pyrolusite, lithophorite, hollandite, todorokite and birnessite, also occurring gibbsite, kaolinite and anatase in varia...
6
artículo
Publicado 2019
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Objective: To evaluate the influence of the cleaning of the cavity with aluminum oxide and pumice on the marginal microfiltration when using ionomeric materials (IV). Materials and Methods: In 40 human premolar teeth, cavities were prepared at the level of the cemetery amelo, the teeth were randomly divided into 4 groups (n: 10) received cleaning and restoration procedures according to the group, G1 cleaning with abrasive air and restoration with IV Ketac Molar Easy Mix (IVKM), G2 abrasive air and restoration with IV Gold Label 2 (IVGL), G3 pumice stone and IVKM, G4 pumice stone and IVGL. After the process of thermal aging, pigmentation with methylene blue and cutting in the lingual buccal direction, the fragments with the highest integrity were analyzed to the stereomicroscope by three evaluators who established the degree of micro filtration at the cervical and occlusal levels; the ave...
7
artículo
Publicado 2017
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Composite material (AC-ZnO) was prepared by growing ZnO nanoparticles during the production of biomass based-activated carbon (AC) via the incorporation of zinc acetate in the process. Comprehensive analyses confirmed the presence of ZnO nanoparticles over the AC surface and described the particular nature of the composite adsorbent. Methylene blue (MB) equilibrium data fitted the Dubinin-Radushkevich model. The MB adsorption capacity was higher for the bare activated carbons (197.9–188.7 mg/g) than the activated carbons with ZnO nanoparticles (137.6–149.7 mg/g). The adsorption of the MB on the adsorbents is physical because the mean adsorption energy (E) is between 1.76 and 2.00 kJ/mol. Experiments that combine adsorption and photocatalysis were carried out with different loads of adsorbents and with and without UV-light exposure. Photocatalytic activity was identified mostly at the...
8
artículo
Publicado 2012
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The aim of the study is the principal parameters establish or to determine for the production of flour of eggplant of excellent quality, depending on the temperature, time of dried and size of the particles of flour, which finally define the performance of the process. One used fruits in his ideal condition of maturity organoléptica, for preventing it from oxidizing for action of the enzimas, there was in use a solution of 80 parts for million (ppm) of metabisulfito of potassium. The temperature of dried was of 65°C during 16h, which was carried out in a dryer of trays of stainless steel, with control of temperature and time. (Dryer of 20 trays of 50 X 40 cm c/u). For the grinding there was used a molino of hammer of stainless steel of 10kg/h, the flour being obtained by size of minor particle of 0.5 mm.
9
artículo
Publicado 2012
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The aim of the study is the principal parameters establish or to determine for the production of flour of eggplant of excellent quality, depending on the temperature, time of dried and size of the particles of flour, which finally define the performance of the process. One used fruits in his ideal condition of maturity organoléptica, for preventing it from oxidizing for action of the enzimas, there was in use a solution of 80 parts for million (ppm) of metabisulfito of potassium. The temperature of dried was of 65°C during 16h, which was carried out in a dryer of trays of stainless steel, with control of temperature and time. (Dryer of 20 trays of 50 X 40 cm c/u). For the grinding there was used a molino of hammer of stainless steel of 10kg/h, the flour being obtained by size of minor particle of 0.5 mm.
10
artículo
Publicado 2022
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Skarn-type deposits show complex mineralogical and textural relationships because of the variety of geological processes involved in their development. Mineral associations can be further complicated by supergene leaching and oxidation. Consequently, hydrothermal alterations constitute complex geochemical signatures to be analysed under a number of factors in these mineralised systems, which are conclusive in vectoring these types of deposits. This study is proposed in order to understand these alterations and to propose their usefulness in the exploration of Cu-Zn skarn deposits. The methodology of bibliographic research and case studies was used, from three main sources of data: information from the Mesozoic sedimentary belt of the Inter-Andean Cordillera and the Yauli dome, case studies from different parts of the world and analysis of the geological, magmatic and petrological conditi...
11
artículo
Publicado 2005
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The oxidation-reduction reactions, typically known as “redox reactions”, are the most important group of chemical reactions. This study proposes a unified procedure for balancing those reactions through an ionelectron method, either in acid or basic medium. Traditionally, balancing is carried out through different stages in most parts of the process.
12
artículo
Publicado 2005
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Las reacciones de oxidación-reducción, generalmente conocidas como reacciones redox, constituyen un grupo de reacciones químicas importantes. En el presente trabajo, se propone un procedimiento unificado para balancear dichas reacciones, empleando el método del ion-electrón, ya sea en un medio ácido ó básico. Por lo general, el balanceo se realiza a través de diversas etapas durante gran parte de su ejecución.
13
artículo
Publicado 2014
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The aim of this study was to evaluate diets enriched with vitamin E and organic selenium on the productive performance and meat quality of rainbow trout (Oncorhynchus mykiss). The study was carried out in the fish farm «El Ingenio» in Huancayo, Peru with 4200 juvenile trout (164 g of body weight) during 40 days. A basal diet (treatment 1), two levels of vitamin E (25 and 50 ppm) and three levels of organic selenium (0.15, 0.25 and 0.35 ppm) were used. In the study, 600 trout were assigned per each of the seven treatments, using three repetitions per treatment (n=200) in a completely randomized design. Body weight gain, feed conversion ratio, and protein efficiency ratio were evaluated. Besides, in the frozen meat content of vitamin E, selenium and total volatile basic nitrogen, and the oxidation state were determined. Data was processed by the analysis of variance, the Tukey multiple c...
14
artículo
Publicado 2014
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El objetivo del presente estudio fue evaluar dietas enriquecidas con vitamina E y selenio orgánico sobre el comportamiento productivo y la calidad funcional del filetede truchas arco iris (Oncorhynchus mykiss). El estudio se hizo en el Centro Piscícola «El Ingenio» en Huancayo, Perú, con 4200 truchas juveniles (164 g de peso) durante 40 días. Se trabajó con una dieta basal (tratamiento 1), dos niveles de vitamina E (25 y 50ppm y tres niveles de selenio orgánico (0.15, 0.25 y 0.35 ppm). Se asignaron 600 peces por cada uno de los siete tratamientos y se tuvo tres repeticiones por cada uno (n=200)en un diseño experimental completamente al azar. Se evaluó la ganancia de peso, conversión alimenticia y eficiencia proteica. Además, se determinó el contenido de vitamina E, selenio, nitrógeno de bases volátiles totales y el estado de oxidación en el filete congelado. Los datos se ...
15
artículo
Publicado 2014
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Chemical composition and technological and nutritional value of "papaya height"(Carica pubescens) also known as "Arequipa papaya" was studied using official AOAC methods and adapting the standard procedure of food technology. The samples were analyzed for physico-chemical proximal composition and content of vitamins and minerals by VIS spectrophotometric method through oxidation-reduction and atomic absorption spectrophotometry. Nutritional technological study was conducted through the elaboration of a processed product to extend the shelf life, the sensory evaluation was performed by quantitative descriptive analysis using hedonic scale and microbiological testing according to Peruvian technical norm NTP 203,108. On average the most relevant results per hundred grams of edible portion were: pH 6,7 to 6,8; acidity 0,08 to 0,09; water 87,7 to 87,54 g; protein 0,49 to 0,52 g; total mineral...
16
artículo
Publicado 2014
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Se estudió la composición química y el valor tecnológico-nutricional de “papaya de altura” (Carica pubescens), también conocida como “papaya arequipeña”, cultivada en la región Arequipa, empleando métodos oficiales de la AOAC y adecuando el procedimiento estándar de la tecnología alimentaria. Las muestras fueron analizadas por su composición fisico-química proximal y el contenido de vitaminas y minerales por método espectrofotométrico VIS mediante oxido-reducción y espectrofotometría de absorción atómica. El estudio tecnológico nutricional se realizó a través de la elaboración de un producto procesado para extender la vida útil, cuya evaluación sensorial se realizó mediante análisis descriptivo cuantitativo empleando escala hedónica y el análisis microbiológico según Norma técnica peruana NTP 203.108. En promedio, los resultados más relevantes por ...
17
tesis doctoral
Publicado 2014
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Universidad Nacional Agraria La Molina. Escuela de Posgrado. Doctorado en Ciencia Animal
18
artículo
Publicado 2018
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Rindermann's cognitive capitalism disregards geographic causes of national wealth and postulates that IQ influences wealth through strengthened institutions, whereas a novel biogeographic theory posits that diminished UV radiation, by reducing cell oxidative stress and fatigue, increases industriousness and improves nations' wealth, thus generating favorable conditions for children's intellectual growth. This study tested predictions from both perspectives and also evaluated whether health + education mediates radiation's cognitive and economic effects. Analyses of data sets encompassing 96 countries yielded well-fitted structural equation models upholding the latter hypothesis and showing that radiation directly influences all variables, cognitive ability and income are unrelated, and the former and institutional strength behave as net dependent variables. The findings suggest that what...
19
tesis de maestría
Publicado 2018
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El presente estudio explica un comparativo cómo influye el incremento de Oxido de Calcio (Cal) en el proceso productivo del Azúcar en los años 2015 y 2016 en una empresa agroindustrial del Norte del Perú. A partir de dicho objetivo se utilizó el diseño es no experimental transversal, sino descriptivo, la técnica de estudio tiene un enfoque cualitativo, los instrumentos a utilizar en el presente estudio de investigación son los registros de datos del área de control calidad de una empresa agroindustrial del norte del Perú en los años 2015 y 2016, y finalmente como herramientas se utilizó gráficas de Control y tablas. Se consideró como muestra representativa la data del área de Control de Calidad de una empresa agroindustrial del norte del Perú, conformado por un total de 216 datos utilizados como muestra correspondiente a los dos años de estudio (2015 y 2016). Los resulta...
20
tesis doctoral
Publicado 2022
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Photoelectrochemical (PEC) processes have become an efficient and viable method for solar energy conversion into zero-emission fuels by harnessing and storage the power of the sun, which offers an environment-friendly approach. Hydrogen is considered as a sustainable and suitable energy alternative in comparison to energy systems based on the consumption of conventional hydrocarbon fuels. In particular, hydrogen production by PEC water splitting represents an attractive alternative to enhance the efficiency of water splitting process using sun light. Current research in this field is devoted to the fabrication and evaluation of new photoactive materials that upon sunlight absorption enable water-splitting PEC reactions with high efficiency and durability. Silicon based compounds offer a good opportunity as photoactive material due to its high abundance and current scalable technologies. ...
