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Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents an experimental investigation on the durability properties of metakaolin (MK) and bottom ash (BA) blended geopolymer under different environmental exposure. The blended geopolymer concrete (GPC) was prepared with sodium based alkaline activators under ambient curing temperature. The concentration of sodium hydroxide used was 8 M. The ratio of sodium silicate to sodium hydroxide was kept as 2.0. The performance of blended geopolymer concrete was compared with conventional concrete (CC). The test results reveal that blended geopolymer concrete develops a better performance against sulphate and acid resistance. Also, MK-BA GPC shows enhanced performance over the conventional concrete in terms of sorptivity, rapid chloride and water absorption. Resumen: Este artículo presenta una investigación experimental sobre las propiedades de durabilidad del geopolímero mezclado con metacaolín (MK) y cenizas de fondo (BA) bajo diferentes exposiciones ambientales. El hormigón de geopolímero mezclado (GPC) se preparó con activadores alcalinos a base de sodio a temperatura ambiente de curado. La concentración de hidróxido de sodio utilizada fue 8 M. La relación de silicato de sodio a hidróxido de sodio se mantuvo en 2,0. Se comparó el desempeño del concreto geopolímero mezclado con el concreto convencional (CC). Los resultados de las pruebas revelan que el concreto geopolimérico mezclado desarrolla un mejor desempeño frente a la resistencia a los sulfatos y ácidos. Además, MK-BA GPC muestra un rendimiento mejorado sobre el hormigón convencional en términos de sortividad y de rápida absorción de cloruro y agua.

In this study concrete pavers replacing natural coarse aggregate with recycled coarse aggregate were manufac-tured. The substitution percentages were 15%, 30% and 45%. The chief characteristics studied for coarse aggregate were particle size, bulk density and specific density. The chief characteristics studied in the pavers were water absorption, density and flexural strength. It was observed that the density of the pavers decreased by increasing percentage of recycled coarse aggregate replacement due to the due to the high porosity of the recycled aggregates. On the other hand, it was found that the pavers with a 15% substitution were the only ones that reached the average flexural tensile strength indicated in the standard. It was concluded that the manufactured pavers can be used in areas with high rainfall or high-water tables, as well as in car parks or sidewalks

The housing problem in Tunisia has become more acute due to the high cost of construction materials, thus constituting a source of concern for the population. To resolve the crisis, upgrading abundant local materials has become a necessity. This paper aimed to assess the potential use of Jebel Menchar's geomaterial to develop compressed earth brick (CEB). Laboratory tests were performed to determine the physical, chemical and mineralogical properties. Series of destructive and non-destructive tests were carried out to characterize the properties of bricks based on their composition in terms of compressive strength, flexural strength, water absorption and ultrasonic testing. The results indicated that all of the bricks studied exhibited a compressive strength greater than 2.3 Mpa during the 28-day experiments, thus suggesting a high potential ability to reduce building material problems, while also providing the brick industry a useful and inexpensive new raw material with less CO2 emissions. Resumen: El problema de la vivienda en Túnez se ha agudizado debido al alto costo de los materiales de construcción, lo que constituye un motivo de preocupación para la población. Para resolver la crisis, la actualización de abundantes materiales locales se ha convertido en una necesidad. Este artículo tuvo como objetivo evaluar el uso potencial del geomaterial de Jebel Menchar para desarrollar ladrillos de tierra comprimida (CEB, por sus siglas en inglés). Se realizaron pruebas de laboratorio para determinar las propiedades físicas, químicas y mineralógicas. Se llevaron a cabo una serie de ensayos destructivos y no destructivos para caracterizar las propiedades de los ladrillos en función de su composición en términos de resistencia a la compresión, resistencia a la flexión, absorción de agua y ensayos ultrasónicos. Los resultados indicaron que todos los ladrillos estudiados exhibieron una resistencia a la compresión superior a 2,3 Mpa durante los experimentos de 28 días, lo que sugiere una capacidad de alto potencial para reducir los problemas de los materiales de construcción, al tiempo que proporciona a la industria del ladrillo una nueva materia prima útil y económica con menos emisiones de CO2.

This study presents the 51 mixtures of ceramic clays characterized by using XRF, XRD, granulometry, and dilatometry analyses. After firing in a 1000–1250 °C range, water absorption (WA) according to EN standards by boiling in water, under vacuum, and by 24 h soaking is determined. The results indicated that there was a high and statistically significant correlation between the standard methods, but the testing under vacuum gave the highest saturation of the samples fired at 1200 °C and 1250 °C. It is determined that these illitic-kaolinitic clays can be used to produce floor ceramic tiles belonging to the BIIa group (water absorption between 3% and 6%).The study also aimed to reveal which method of WA determination is suitable to read the sintering interval from the gresification diagrams, which is compared to the beginning of sintering as read from dilatometry curves. Resumen: Este estudio muestra la caracterización de 51 mezclas de arcillas cerámicas, mediante análisis XRF, XRD, granulometría y dilatometría. Después de calentar las muestras en el intervalo de 1.000-1.250 °C, se ha determinado la absorción de agua (WA), de acuerdo con las normas EN mediante ebullición en agua, al vacío y en remojo durante 24 horas. Los resultados confirman que existe una correlación estadística alta y significativa entre los diferentes métodos estándar, aunque los ensayos a vacío dieron la mayor saturación de las muestras calentadas a 1.200 y 1.250 °C. Se ha determinado que estas arcillas ilítico-caoliníticas pueden ser utilizadas para la fabricación de baldosas cerámicas de suelo pertenecientes al grupo BIIa (absorción de agua entre 3 y 6%).El estudio también pretendía demostrar qué método de determinación de WA es adecuado para establecer el intervalo de sinterización, que se compara con el comienzo de la sinterización observado según las curvas de dilatometría.

El pan es un alimento de consumo masivo que puede mejorarse nutricionalmente mediante el agregado de distintos ingredientes. La harina de avena (Avena Sativa L.) con harina de trigo pan de buena calidad industrial se podrían combinar para obtener productos panificados con características aceptables para el consumidor y mejoras nutricionales. El objetivo de este trabajo fue analizar fisicoquímicamente las características de harinas de diferentes variedades de trigo y avena para ser utilizadas en panificación. Para esto se utilizaron tres variedades de trigo pan y nueve variedades de avena, dichos cultivares provistos por la Chacra Experimental INTA- Barrow. Se realizaron distintas pruebas de calidad industrial de granos y harinas y una caracterización nutricional/química de las mismas. Finalmente, se evaluó su vida útil. La calidad de grano del trigo pan, mostró que los tres materiales tuvieron buena performance. Dentro de las características de calidad industrial, B. Meteoro fue superior. Se logró ajustar un protocolo para el tratamiento térmico de los granos de avena y para la determinación de actividad la lipasa de las muestras. La calidad nutricional de las variedades de avena, dieron: valores de contenido de proteína elevados, los contenidos de contenido de ceniza, fibra y lípidos fueron similares a los observados en bibliografía. Los b-glucanos mostraron, en todas las variedades, valores superiores a los descriptos en la bibliografía. El análisis de vida útil de harinas, durante 10 meses de almacenamiento, no mostró evidencias de perdida de vida útil según los indicadores utilizados y los límites definidos por el Codex Alimentarius.

One aspect that affects the strength of Portland cement mortars is the correction of moisture in the mix. Thus, standard techniques are usually used to obtain the absorption value in fine aggregates; one of them is the standard ASTM C128. However, the ASTM C128 presents variability associated with the identification of the saturated surface dry state in the fine aggregates. This research compares the water absorption of four types of Colombian aggregates obtained using the ASTM C128 and an innovative instrumental and analytical technique with the thermogravimetric balance of halogen light (TBHL), coupled with a software that reads the retained water data in real time. The strength of mortars designed on the basis of moisture correction is also evaluated. The absorption results show that TBHL presents lesser dispersion results (not exceeding 10%) than the standard method ASTM C128, indicating greater precision and less uncertainty. Additionally, resources are optimized through TBHL implementation, requiring 25% less time, 86% less energy consumption, and 98% less fine aggregate for a test. Furthermore, the strength of the mortars varies depending on the method used to determine the absorption, as well as the morphology of the aggregates. The accuracy of TBHL allows better correction of the water-cement ratio in the mortars; thus, leading to higher performance. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Enviromental Sciences & Natural Resources / Revista de Ciencias Ambientales & Recursos Naturale is the property of ECORFAN-Mexico S.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study concrete pavers replacing natural coarse aggregate with recycled coarse aggregate were manufactured. The substitution percentages were 15%, 30% and 45%. The chief characteristics studied for coarse aggregate were particle size, bulk density and specific density. The chief characteristics studied in the pavers were water absorption, density and flexural strength. It was observed that the density of the pavers decreased by increasing percentage of recycled coarse aggregate replacement due to the due to the high porosity of the recycled aggregates. On the other hand, it was found that the pavers with a 15% substitution were the only ones that reached the average flexural tensile strength indicated in the standard. It was concluded that the manufactured pavers can be used in areas with high rainfall or high-water tables, as well as in car parks or sidewalks. [ABSTRACT FROM AUTHOR]

The main objective of this research study was to develop a bilayer active biocomposite (BA) from cassava bran, fique, and glycerol with a coating of polylactic acid (PLA) and nisaplin® that would allow its implementation in high humidity food matrices. Mechanical and thermal properties, water absorption, and antimicrobial effect on Escherichia coli were evaluated. A one-factorial completely randomized experimental design was performed with four concentrations of nisin. The flexural test revealed that the addition of PLA and nisin had no significant effect on stress or flexural modulus. Thermal analysis by differential scanning calorimetry (DSC) resulted in two endothermic peaks, one exothermic peak, and one glass transition peak. The BA's water absorption test had a percentage of 35%. It is concluded that the BA had no inhibitory effect on E. coli, but showed promissory potential for its application in high humidity foods. [ABSTRACT FROM AUTHOR]

Introduction--Currently, the development of materials from renewable resources is growing worldwide; non-wood lignocellulosic fibers from different plant species or agro-industrial residues are an interesting source of raw material. Objective--The objective of this work is the development and physical-mechanical characterization of a composite material based on Musa acuminata pseudostem particles and a thermosetting resin. Methodology--The composite was prepared with particles of an average size of 450 μm, washed with a NaOH solution and oven-dried at 70 °C for 24 h. The moisture content was controlled. In manufacturing, the particles were glued with urea formaldehyde resin in a drum-type mixer and pressed in thermal plates at 160°C and 107 psi. The composites were analyzed mechanically, obtaining data on modulus of rupture, elastic modulus and tensile strength. Penetration hardness and water absorption resistance tests were also performed. Moreover, thermographic tests were performed on the surface of the material. The results were compared with those obtained in commercial composites. Results--It was observed that the Musa acuminata composite presented greater resistance to moisture absorption, higher elastic modulus and was more resistant to tensile stresses. Additionally, the commercial composite showed lower penetration resistance. The Musa acuminata composite achieved higher thermal insulation in thermographic tests. Conclusions--Musa acuminata is a species with a high agro-industrial flow and a considerable producer of residues, which has interesting viable physical-mechanical characteristics to produce particle agglomerates that meet engineering standards. [ABSTRACT FROM AUTHOR]

En esta investigación fueron fabricados compuestos de partículas de Guadua angustifolia Kunth con tamaños de 500 µm y 300 µm con matriz polimérica. El objetivo fue evaluar las propiedades físico-mecánicas de los compuestos y compararlas con los resultados obtenidos en compuestos comerciales. Las propiedades mecánicas fueron analizadas usando un diseño factorial general con un factor, dos niveles y tres variables de respuesta. La adhesión de las partículas de guadua demostró mayor resistencia a esfuerzos de tracción y módulo de elasticidad frente al obtenido en compuestos comerciales. Los compuestos de guadua presentaron mayor resistencia a la penetración debido al menor volumen de espacios vacíos entre partículas. En pruebas de absorción de agua, los compuestos de guadua tuvieron hasta un 69 % de absorción y 16 % de incremento de espesor en 24 h frente a 86 % y 22 % respectivamente en compuestos comerciales. Asimismo, en pruebas mecánicas el compuesto de guadua 500 µm fue un 23% de mayor resistencia en flexión frente al compuesto comercial. Además, los compuestos guadua 500 µm y 300 µm tuvieron mayor resistencia a la tracción hasta en 57% y 32% respectivamente en comparación al compuesto comercial. En pruebas de dureza los compuestos de guadua mostraron mayor resistencia a la penetración frente al compuesto comercial.

In this investigation, Guadua angustifolia Kunth particles composites with sizes of 500 µm and 300 µm with polymer matrix were manufactured. The goal was to evaluate the physical-mechanical properties of the composites and compare them with the results obtained in commercial composites. The mechanical properties were analyzed using a general factorial design with one factor, two levels and three response variables. The adhesion of guadua particles showed greater resistance to tensile stresses and modulus of elasticity compared to that obtained in commercial composites. Guadua composites showed greater resistance to penetration due to the smaller volume of empty spaces between particles. In water absorption tests, guadua composites had up to 69% absorption and 16% thickness increase in 24 hours versus 86% and 22% respectively in commercial composites. Also, in mechanical tests, the 500 µm guadua composites was 23% higher in flexural strength compared to the commercial composite. In addition, the 500 µm and 300 µm guadua composites had greater tensile strength of up to 57% and 32% respectively compared to the commercial composite. In hardness tests, the guadua composites showed greater resistance to penetration compared to the commercial composite. [ABSTRACT FROM AUTHOR]

The design of experiments is applied to find the optimum proportion of components for the samo # 4 block mix in the company Gres Caribe S.A. (Barranquilla, Colombia). The NTC 4205-1 standards for resistance to compression and water absorption were considered. Statistical analysis of collected data was assisted with Statgraphics Centurion XVI. Preliminary field tests established the limits of each component to determine the experimental region. The candidate points were selected under the D-optimal criterion and the regression model chosen. There are twenty points (o candidate mixtures) in total, thus twenty runs were required for the experiment. By maximizing the desirability function, the optimal mixture for the block was determined: 54.3091% clay, 37.5507% sand and 8.14017% water. Five field runs with this mixture showed that the property values of the new blocks exceeded the properties of the blocks manufactured with the old mixture. These blocks also meet the required standards. A savings of $ 9,606 / manufactured block is achieved, equivalent to a percentage decrease of 4.41%, quantified at COP 153'023,580 / year. [ABSTRACT FROM AUTHOR]

In order to study the influence of dry-wet cycling on the deterioration characteristics of gypsum rocks and solve the problems encountered in engineering construction, in this study, gypsum rocks are taken as the research object. With the combination of laboratory test and theoretical analysis, the numerical simulation of particle flow is carried out, and the deterioration characteristics of physical and mechanical properties of gypsum rock under dry-wet cycling are studied. The results show that gypsum, quartz, zeolite and dolomite are the main components of gypsum rocks. Gypsum occupies the most components in gypsum rocks, so the various characteristics of gypsum greatly affect the characteristics of gypsum rocks. The process of water absorption and loss of gypsum is similar, which shows that the rate of water absorption or loss of gypsum is faster in the early stage, and tends to be stable in the later stage. The curve of the whole process of water absorption and loss is fitted by negative exponential function, and the effect is better. The larger the porosity of gypsum rock is, the better its water absorption performance is. Intergranular pore, dissolution pore and dissolution pore are the main pore types of gypsum rock. Intergranular pore is the main water absorption channel of gypsum rock. The cumulative water absorption increases with the increase of wetting and drying cycles. The change of water absorption curve is mainly manifested in water absorption rate and time. The more the number of wet-dry cycles is, the higher the water absorption rate in the early stage of water absorption is, the closer the characteristic curve to the coordinate axis of water absorption is, and the shorter the water absorption time is. In contrast, the shape difference of water loss curve is very small. It can be seen from this that in the process of wetting and drying cycle, the hydrophysical and hydrochemical processes promote each other, which changes the crystal structure and pore structure of gypsum rocks, reduces the crystal strength and increases the porosity, thus leading to the deterioration of the mechanical properties of gypsum rocks. [ABSTRACT FROM AUTHOR]

Este trabajo estudia las propiedades mecánicas y físicas de hormigones estructurales fabricados con áridos reciclados obtenidos de residuos de construcción y demolición. Se han seleccionado mezclas con una relación específica agua / cemento y una sustitución de agregados gruesos y finos similares. Se han comparado los resultados de la deformación, la resistencia a la compresión, la resistencia a la rotura por fraccionamiento, el módulo estático de elasticidad, la deformación por contracción, la densidad aparente y los ensayos de absorción de agua. Los datos muestran que las propiedades más afectadas debido a la sustitución de agregados naturales por agregados reciclados son la trabajabilidad, el módulo de elasticidad, la deformación por contracción y la absorción de agua. Abstract This work studies the mechanical and physical properties of structural concretes made by recycled aggregates obtained from construction and demolition waste. Mixes with a specific water/cement ratio and a similar coarse and fine aggregate substitution have been selected. Results from slump, compressive strength, splitting tensile strength, static modulus of elasticity, shrinkage strain, bulk density and water absorption tests have been compared. The data show that the most affected properties because of natural aggregate substitution for recycled aggregates are workability, modulus of elasticity, shrinkage strain and water absorption.

La meta de este trabajo fue el mejoramiento de las propiedades mecánicas de un bioplástico a base de almidón mediante la adición de dióxido de titanio (TiO2). Los materiales se sintetizaron por mezclado con glicerol y agua a 70 °C bajo condiciones de agitación constante, y se moldearon naturalmente en cajas Petri hasta obtener láminas. La caracterización se realizó por análisis de perfil de textura para determinar sus propiedades mecánicas, espectroscopía infrarroja para determinar sus grupos funcionales y absorción de agua para evaluar su permeabilidad. Se determinó que el uso de TiO2 mejora la resistencia mecánica y el módulo de elasticidad en un 30 y 17%, respectivamente, y disminuye su capacidad de absorción de agua en un 40%. Esta modificación en el comportamiento puede estar relacionada con la naturaleza hidrofóbica del TiO2. [ABSTRACT FROM AUTHOR]

Copyright of Informador Técnico is the property of Servicio Nacional de Aprendizaje SENA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

En casa de malla de la Universidad Nacional de Colombia sede Palmira (3° 30' 45.6" N y 76° 18' 29.911" O, 1050 m.s.n.m., 23.5 °C y 77% de HR) se midieron los requerimientos hídricos del cilantro (Coriandrum sativum L.) variedad Unapal Precoso y se relacionaron con el rendimiento de follaje fresco y materia seca. Las plantas fueron sembradas en macetas con 6 kg de suelo y por ciclo de cultivo se aplicaron láminas de agua de 140, 160, 200 (testigo propuesta por Vallejo y Estrada, 2004), 240 y 280 mm. Se utilizó un diseño completamente al azar con cinco tratamientos, cuatro repeticiones y 36 plantas por unidad experimental. Cada día, durante la fase experimental, se realizaron mediciones de evapotranspiración y cada 35 días después de la siembra se midieron las producciones de follaje y biomasa. La mayor producción de follaje se obtuvo con 200 mm de agua, valor asociado con la mayor eficiencia en el uso de ésta, medida como producción de MS, (0.64 g/lt de agua aplicado). En la etapa de germinación el coeficiente Kc del cultivo (relación evaporación real/evaporación de referencia) fue de 0.83, 1.12 en la etapa de crecimiento lineal y 1.40 en la etapa de formación de tallo floral y cosecha.

The present work studies the principal variables of control in the manufacturing process of construction pieces of the Metropolitan Area of San Jose de Cucuta by extrusion and pressing techniques for its forming. The investigation was taken out using clayey samples of the two principal geological formations of the region where the raw material is taken for processing at an industrial level. The clayey samples milling was made by dry means as well as by moisture means and its particle size was measured. Subsequently the forming process was taken over by using an hydraulic press and extruder with vacuum system , both equipments at laboratory scale, the pieces shaped were dry and firing between 980° c and 1180° at the end of the process the tests were made to determine water absorbtion, contraction and mass loss at the pieces firing. The study results left to see that the extrusion technique allowed a faster vitrification for the region’s clay in comparing with the pressing technique, the contractions of drying and firing are less marked on the pressing techniques with standard deviations much lower than in extrusion.El presente trabajo estudia las principales variables de control del proceso de fabricación de piezas cerámicas de construcción de la zona metropolitana de San José de Cúcuta, mediante las técnicas de extrusión y prensado para su conformado. La investigación se llevó a cabo utilizando muestras arcillosas de las dos principales formaciones geológicas de la región de donde se extraen las materias primas para el proceso a nivel industrial. Las muestras arcillosas se molturaron tanto por vía seca como por vía húmeda y se estudió su granulometría. Posteriormente se llevó a cabo el proceso de conformado utilizando una prensa hidráulica y una extrusora con vacío, ambos equipos a escala de laboratorio. Las probetas obtenidas se secaron y cocieron entre 980 ºC y 1180ºC al final del proceso se realizaron pruebas para determinar la absorción de agua, contracción y pérdida de masa en cocción de las probetas. Los resultados de la investigación dejaron ver que la técnica de extrusión permite una gresificación más rápida para las arcillas de la región en comparación con la técnica de prensado, las contracciones de secado y cocción son menos marcadas en la técnica de prensado y con desviaciones estándar mucho mas bajas que en el caso de la extrusión.

Dados los requerimientos actuales en materiales plásticos no contaminantes, se llevó a cabo el estudio del efecto de un aditivo Masterbatch sobre las propiedades mecánicas, de barrera y ópticas de un polímero elaborado por extrusión-soplado a partir de almidón de yuca, ácido poliláctico (PLA) y Masterbatch gris (MBG). Se estableció que la película presentó una permeabilidad al vapor de agua en el día 90 de seguimiento (5,75E-14 g/m*s*Pa), en el caso de la permeabilidad al oxígeno el valor más bajo se presentó en el día 30 (9,57503E19 mol/m*s*Pa), la absorción de agua y porcentaje de solubilidad decrecieron a lo largo del tiempo pasando de 97,9% (día 8) a 86,3% (día 90) y 25,41% (día 8) a 19,61% (día 90), respectivamente. En relación a la resistencia máxima a la tensión no hubo diferencia significativa durante el tiempo de evaluación, se presentó una disminución en el módulo de Young (235,50 a 173,10 MPa) y aumentó la elongación máxima en el punto de rotura (2,64 a 11,34 %). En cuanto al color, las muestras presentaron una luminosidad superior al valor de 50, es decir, neutralidad en el color, de igual forma con respecto a Chroma (o saturación) (promedio de 1,46) y una tendencia hacia el neutro en el matiz por sus valores cercanos a 0. Como prueba de apoyo se realizó una prueba de Calorimetría Diferencial de Barrido (DSC).

Dentro del Programa Europeo LIFE, se ha desarrollado un proceso de microencapsulación de mercurio liquido, utilizando la tecnología de estabilización/solidificación con azufre polimérico (SPSS). Como resultado se ha obtenido un material estable tipo concreto que permite la inmovilización de mercurio y su almacenamiento a largo plazo. La descripción del proceso y la caracterización de los materiales obtenidos, denominados concretos Hg-S, se detallan en la Parte I. El presente trabajo, Parte II, incluye los resultados de los diferentes ensayos realizados para determinar la durabilidad de las muestras de concreto Hg-S con un contenido de mercurio de hasta el 30 %. Se han utilizado diferentes métodos de ensayo estándar, UNE y RILEM, para determinar propiedades como la absorción de agua por capilaridad, la permeabilidad de agua a baja presión, la resistencia a álcali y ácido, el comportamiento en niebla salina, y la resistencia al hielo-deshielo y al fuego. Las muestras presentaron una capilaridad extremadamente baja y una resistencia alta tanto a álcali como a ácido. También mostraron una elevada resistencia en condiciones ambientales muy agresivas como niebla salina, hielo-deshielo y humedad-sequedad.

Este trabajo presenta el estudio experimental de las propiedades de durabilidad del hormigón activado alcalinamente (AAS) y expuesto a carbonatación. Las propiedades de durabilidad fueron estudiadas a través de las mediciones de resistencia a la compresión, permeabilidad, absorción de agua y la penetración de ion cloruro. Los resultados muestran que los hormigones AAS, generan una mayor resistencia a la compresión a edades tempranas en comparación con los hormigones OPC. En contraste con las medidas de permeabilidad y absorción de agua las cuales fueron más bajas para el hormigón AAS con respecto a los OPC.

Quinoa (Chenopodium quinoa willd) is a pseudocereal produced for many years in Andean regions and allows different transformations taking advantage of their nutritional qualities becoming it a food agribusiness alternative. Objective of this study was to observe physical and chemical changes from two quinoa flour varieties (Blanca dulce de Jericó and Tunkahuan) during extrusion process and determine conditions (flour moisture, temperature and screw speed) that allow obtain an extruded similar to precooked functional properties. Water absorption index (IAA), water solubility index (ISA) and swelling power (PH) was response variables. Two flour extruded at 105°C degrees, 150 rpm screw speed and 25 to 30% moisture improved functional properties (IAA increased from 1,81 g gel/g D.M to 4,22 g gel/g D.M in Tunkahuan extruded quinoa flour and 2,00 g gel/g to 4,27 g gel MS/ MS g flour in Blanca dulce de Jericó) but nutritional properties decreased as digestibility except for a carbohydrate content increase. [ABSTRACT FROM AUTHOR]

There is a large number of plastics materials currently consumed for human benefit, Polyethylene Terephthalate (PET) is one of the most commonly used in the plastic industry. When discarded, this kind of plastic results highly polluting due to its slow degradability (approximately 100 years), representing a serious problem when packages are finally disposed of. For this reason, it is important to find an alternative and appropriate use for plastic waste. To this end, the Centro Nacional de Investigación y Certificación en Vivienda, Hábitat y Desarrollo Urbano (CENVIH) carried out research project with the main goal of assessing the physical and mechanical properties of concrete masonry using PET as an additive, meeting the specifications of the Venezuelan regulation COVENIN 42-82. To accomplish this, both traditional and PET blended blocks (volume substitution of the fine aggregate with different percentages of shredded PET) were tested. The results show that the compressive strength of the masonry unit with PET decreases as the plastic content increases. To conclude, it is technically viable to use concrete masonry with a 10 % substitution of PET as non-structural construction elements, since it meets the specifications of COVENIN 42-82. [ABSTRACT FROM AUTHOR]

Due to the current requirements in clean plastic materials, the project was conducted to study the effect of a masterbatch additive on mechanical properties (stress analysis), barrier (desiccant method), optical (CIELab and CIECh scale) of a polymer composed by cassava starch, polylactic acid (PLA) and grey masterbatch (MBG) and by using the blown film extrusion technology polymer. It was established that the films has a permeability to water vapor on the 90th day of monitoring (5,75E-14 g/m*s*Pa), in the case of the oxygen permeability, the lower value occurred on day 30 (9,57503E19 mol/m*s*Pa), the water absorption and the solubility percentage decrease throughout changing to 97,9% (day 8) a 86,3% (day 90) y 25,41% (day 8) a 19,61% (day 90), respectively. In relation whit the tensile modulus there wasn't significant difference during the evaluation time, a decrease occurs in Young modulus (235,50 to 173,10 MPa) and the maximum elongation at break point (2,64 to 11,34%). Regarding color, samples presented a luminosity value over 50, that is, neutrality in color; in the same manner in relation to Chroma (or saturation) (average value of 1,46) and a trend to neutral position on hue due to values close to 0. As supporting evidence was realized a Differential Scanning Calorimetry (DSC) test. [ABSTRACT FROM AUTHOR]

Agglomerates made from lignocellulosic particles from plants found in the region of Quindio - Colombia such as "guasca de plátano", "tripeperro" and "pasto elefante", were obtained and they were compared with wood commercial agglomerates purchased on the local market. These particles were mixed with a thermosetting resin, and pressed under temperature for a certain time and then allowed to cure at room temperature. At the conclusion of the manufacturing process and curing, the agglomerate was subjected to mechanical analysis of bending, tension, compression, hardness and water absorption according to ASTM standards for wood particleboard. The agglomerate was also subjected to thermography analysis in order to observe its thermal insulation. Results show that the agglomerates made by us, present better results than the commercial one regarding water absorption, thermal insulation and hardness and similar results in the mechanical tests of bending, tension and compression, except to the agglomerate of "tripeperro". [ABSTRACT FROM AUTHOR]

The suitability of shale materials from the Iberian Massif in the Jaén province (Spain) to make ceramic materials has been evaluated. The main components of these shales are illite, kaolinite, quartz and feldspars, with lesser amounts of chlorite, pyrophyllite, paragonite and chlorite/vermiculite mixed-layers. The materials contain high amounts of alumina (17-21 %), and iron oxide vary over a wide range (1.33-9.21 %). Grain-size analysis shows that more than 90% is En este trabajo se ha evaluado la aplicabilidad para fabricar materiales cerámicos de las pizarras del Macizo Ibérico de la provincia de Jaén. Los principales componentes de estas pizarras son illita, caolinita, cuarzo y feldespatos, con menores contenidos de clorita, pirofilita, paragonita e interestratificado clorita/vermiculita. Estos materiales tienen altos contenidos de alúmina (17-21%), mientras el oxido de hierro varía en un amplio intervalo (1.33-9.21%). Los análisis granulométricos muestran que más del 90% de las partículas son

En el mejoramiento genético de una especie se requiere de la caracterización de los progenitores utilizados en el mismo, a fin de conocer su utilidad como fuente gen��tica de un carácter determinado, así como para planear las combinaciones apropiadas. La presente investigación tuvo como objetivo la caracterización de un grupo de 49 genotipos de Phaseolus vulgaris y uno de Phaseolus coccineus, en cuanto a las características físicas, de calidad culinaria y nutricional del grano. La variedad Blanco Tlaxcala (P. coccineus) presentó mayor tamaño de grano y menor contenido de proteína que los genotipos de P. vulgaris. El 86% de los genotipos evaluados mostraron tiempos de cocción menores a 115 min, característica relacionada con la capacidad de absorción de agua (r=-0.78 **). Redlands Pioneer e ICA Zerinza resultaron de cocción rápida y Perry Marrow, Kaboon e ICA Zerinza pueden ser utilizados para desarrollar variedades con bajo contenido de testa. Los genotipos G 2333, Negro Lolotla, REN 27 y J 117 mostraron alto contenido de proteína. BY 94022, Pinto Villa y Negro 150 presentaron la menor actividad de inhibidor de tripsina en frijol cocido. Se encontró suficiente variación genética en la mayoría de las características de calidad determinadas, por lo que existe la posibilidad de su mejoramiento a través de la recombinación y selección.Physical, culinary and nutritional characterization in dry bean from the semiarid highlands of Mexico. In the improvement of a given crop species, knowledge on the grain quality and related traits in the progenitors used in the breeding process is needed to establish their usefulness as a source of a given character, and as well as to plan the proper combinations between progenitors. The aim of the present research was to characterize a group of 49 genotypes of Phaseolus vulgaris and one of Phaseolus coccineus, in relation to physical, cooking and nutritional grain traits. Cultivar Blanco Tlaxcala (P. coccineus) showed a larger grain size and lower protein content than any of the P. vulgaris cultivars. The 86% of the studied genotypes showed cooking times lower to 115 min, and a significant correlation between this trait and water sorption capacity (r=-0.78 **) was found. Cultivars Redlands Pioneer and ICA Zerinza could be used as source of low cooking time; and Perry Marrow, Kaboon and ICA Zerinza in the production of low shell content cultivars. Genotypes G 2333, Negro Lolotla, REN 27 and J 117 showed the highest grain protein content. On the other hand, BY 94022, Pinto Villa and Negro 150 had the lowest trypsin inhibitor activity. Results support the possible use of the above genotypes as sources of those grain traits. In general, large variability was found for most of the quality traits determined; therefore, there is scope for improvement through recombination and selection.

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The purpose of this investigation was to determine the physicochemical, textural and sensorial characteristics of gluten-free spaghetti elaborated with unripe plantain, chickpea and maize flours. Luminosity (L*) of the uncooked gluten-free spaghetti was not significantly different from control sample, but in cooked spaghetti,L* value was different. The diameters of raw spaghetti (gluten-free and control) were similar, but lower diameters were determined in cooked gluten-free spaghetti; however, some composites had similar water absorption values. Gluten-free spaghetti had higher hardness, cohesiveness and chewiness than the control but had lower elasticity. The maximum peak viscosity was lower in the gluten-free spaghetti than in the control, and no breakdown viscosity was observed, although high setback viscosity was found. The overall sensorial acceptability was similar in the gluten-free spaghetti among the different formulations, but it was significantly lower than the control. It is possible to prepare gluten-free pasta with textural and overall acceptability. [ABSTRACT FROM PUBLISHER]