Orange peels (Citrus sinensis) are an abundant lignocellulosic residue that can be used as a carbon source to obtain solids with catalytic potential in the transformation of terpenes and their oxides into value-added products. This research seeks to evaluate the isomerization of α-pinene epoxide to campholenic aldehyde using a catalyst obtained from orange peels. The material OAC-Zn was obtained by activation of orange peel with ZnSO4.7H2O followed by thermal treatment at 500 °C; an additional solid was obtained from orange peel by pyrolysis at 500 °C (OC-500). XRD revealed the presence of ZnO and ZnS in OAC-Zn; TGA analysis indicated thermal stability in OAC-Zn and OC-500 materials; SEM images showed porous surfaces of different morphology, and the presence of microporosity in OC-500 and mesoporosity in the OAC-Zn that was confirmed by physical nitrogen adsorption. The elements C, O, Zn and S was identified in OAC-Zn by EDX analysis. The results of TPD-NH3 showed that the solids contained medium and weak acidity. Campholenic aldehyde was synthesized with a 96 % selectivity over a mesoporous carbonaceous material obtained from orange peels using ZnSO4.7H2O as activating agent

The growth of RDF (Resource Description Framework) datasets and the expansion of their use in conjunction with the definition of SPARQL, a declarative query language, have made RDF data management an active area of research and development. In this regard,mechanisms have been proposed to help users find their desired answers in less time, including ranking methods and preference-based queries. Skyline queries constitute one of the most practical and predominant types of preference-based queries. The aim ofthis work was to provide a guide to specifying SPARQL skyline queries using syntax proposed in state-of-the-art works, and SPARQL versions 1.0 and 1.1. The results show the possibility of rewriting skyline queries in SPARQL to express preferences. We planto develop a tool to translate SPARQL skyline queries applying the different grammars proposed, into SPARQL 1.0 and 1.1 with the aim of providing an automatic mechanism of translation.

AbstractMany differrent solid wastes are deposited in landfills which may lead to leaching processes with groundwater pollution implications. Complex fractions of organic pollutants may transfer from the soil with multiplex physicochemical interactions which reduce the final soil-borne. In this paper, we study the potential removal of a dye and the potential of water infiltration in each layer of a soil. The results show a removal >98% in the complete profile and in the silty layer (SL) in which more infiltration was found. Therefore, organic fraction in the SL and even more interaction with the aluminum and silicates present, may reduce the dye by physicochemical interaction with log Koc properties. Also, more infiltration in SL indicates a strong interaction between dissolve analytes and soil due to despite a large amount of water cross the silt, low infiltered levels is presented. Finally, pH slightly acid from 4.5 in the sample was increased to 6.7 which indicates basic condition for neutralization, while conductivity was reduced even to values presented in tap water due to ionic exchange capacity by the soil. A preliminary conclusion indicates that removal of the first layer in a landfill reduces the capacity of pollutants removal in soils and, therefore, low physicochemical interactions may lead to the leaching of pollutants to waterbodies. However, further experiments are needed to strengthen this study.ResumenMuchos residuos solidos son depositados en rellenos sanitarios, lo que puede conducir a procesos de lixiviacion con implicaciones de contaminacion del agua subterranea. Las fracciones complejas de contaminantes organicos pueden transferirse desde el suelo con una interaccion fisicoquimica que reduce su paso final al agua. En este trabajo, se evaluo la eliminacion de un colorante y el potencial de la infiltracion del agua en cada estrato de un suelo. Los resultados muestran una eliminacion > 98% en el perfil completo del suelo y en el estrato limoso (SL) en el que se encontro mas infiltracion. Por lo tanto, la fraccion organica en el SL y la interaccion con el aluminio y lossilicatos presentes, pueden reducir el colorante por interacciones fisicoquimicas con propiedades de log Koc. Ademas, una mayor infiltracion en SL indica una fuerte interaccion entre el colorante y el suelo debido a que, aunque una gran cantidad de agua atraviesa los limos, se presentan bajos niveles infiltrados del colorante. Finalmente, el pH ligeramente acido de 4,5 en la muestra se incremento a 6,7 lo que indica una condicion basica para la neutralizacion, mientras que la conductividad se redujo incluso a los valores presentados en el agua del grifo debido a la capacidad de intercambio ionico del suelo. Una conclusion preliminar muestra que la eliminacion del primer estrato en un relleno sanitario reduce la capacidad de eliminacion del suelo y, por lo tanto, pocas interacciones fisicoquimicas pueden llevar a la lixiviacion de contaminantes a cuerpos de agua. Sin embargo, deben llevarse a cabo mas estudios en el futuro. https://doi.org/10.22209/rt.v43n2a04

Se reporta la caracterizacion de una mezcla asfaltica, modificada con desechos especiales proveniente de baterias de automoviles. La modificacion se realizo por via seca y se evaluo la relacion de vacios que caracteriza la calidad de una mezcla asfaltica, en el material modificado y sin modificar. El estudio se realizo anadiendo en peso porcentajes de 5%, 15%, 25% y 35% de escoria a la mezcla asfaltica. Los resultados obtenidos de la integracion de desechos especiales a la mezcla, indican que dicha modificacion mejora sus propiedades mecanicas y el rendimiento de los materiales al momento de ser usados en la mezcla. En comparacion con la mezcla sin modificar, la muestra modificada presento un aumento de un 30% en estabilidad y un 8% en flujo, lo que predice una mejora en las propiedades mecanicas de la mezcla en cuanto a aumento en resistencia. Por otro lado, las propiedades volumetricas de la mezcla modificada se mantuvieron en el rango dispuesto en la norma y el ensayo de modulo de rigidez, que determino el comportamiento del pavimento en sitio, igualmente aumento. Lo que demuestra las ventajas de modificar la mezcla asfaltica con la escoria de baterias desechadas.

Water sorption data of the peeled bean and shell of Trinitario fermented and dry cocoa beans were determined at 25 °C and adjusted to the isotherm models of Brunauer-Emmet-Teller-(BET) and Guggenheim-Anderson-de Boer-(GAB). The difference in the moisture sorption capacity of the shell and peeled beans was clearly established. The monolayer water contents estimated using the BET and GAB models for the peeled bean was 3.53 and 3.60 g water/100 g dry solids, respectively; while for the shell were 8.42 and 8.50 g water/100 g dry solids. The energy constants (C) obtained applying the BET model for the peeled bean and shell were 154.3 and 163.2, respectively. Those estimated from the GAB model (C´) were 21.63 and 83.56, respectively. A larger C´ value for the shell indicates stronger water binding to the active sites in the monolayer as compared with the peeled beans that could indicate the presence of more active polar sites in the former. The value of the K constant in the GAB model was 0.871 and 0.942 for the peeled bean and shell respectively that could suggest a larger water adsorption by proteinaceous material in the peeled bean.

Spite of continuously deforestation in Chile in the last 40 years, the production of combustion pellets is increased, being the main producer Ecomas. For this study, it was testedwalnut and wheat shells, waste paperboard and waste Kraft paperas raw materials for17 formulations of pellets. Only 8 formulations were successful for pellet production. The 8 pellets obtained and Ecomas pellet were compared according to ash and moisture content and heating value (HHV). The pellets obtained indicated a better HHV and moisture content but a higher ash content than Ecomas pellet. Moreover, 8 pellets and Ecomas pellet were compared with the set values inEuropean Norm EN 14961-2, indicating that pellets 5 and 6, meet the EN 14961-2. In view of the results achieved, the mixtures used in this study could considered as promising raw material for the production of combustion pellets with similar characteristics as commercial pellet Ecomas.

Los sistemas que implican una espera antes de la atención se enmarcan dentro de la Teoría de colas.Este trabajo busca comparar las medidas de desempeñoen colas no markovianas.Para ello se simularon sistemas de cola única, que se conformaron a partir de las combinaciones de las distribuciones de tiempos entre llegadas (normal, lognormal, Weibull o triangular), sus parámetros (Prueba 1, Prueba 2 o Prueba 3), y las distribuciones de los tiempos de servicio (constante o triangular). Algunos resultados muestran que al comparar individualmente cada medida de desempeño, para sistemas que mantienen constante los parámetros de llegadas, las distribuciones de servicio, y varían la distribución de tiempos entre llegada, su comportamiento conjunto es estadísticamente distinto. Por su parte, los sistemas que incluyeron distribuciones de entrada normal o uniforme, fijando los parámetros de la distribución con una o dos desviaciones estándar (1s; 2s), y la distribución de servicio, mostraron que en la evaluación de cada medida de desempeño particular, tenían valores estadísticamente iguales. En el caso de los sistemas que incluían los parámetros con la mayordesviación estándar y las distribuciones lognormal y Weibull, o lognormal y uniforme, presentaron comportamiento estadísticamente similar en tres de cuatro medidas de desempeño.

Se sintetizaron zeolitas con fase *BEA y se determino la relacion de las condiciones de sintesis con la composicion final del solido. Los datos de acidez muestran una tendencia lineal con la cantidad de cationes alcalinos intercambiados con amonio.  A partir de las zeolitas sintetizadas se prepararon catalizadores para su evaluacion en la reaccion hidrocraqueo de un gasoleo de vacio, donde los catalizadores mas activos son aquellos que presentaron mayor acidez y mayor cantidad de aluminio incorporado en la estructura de la zeolita. Se resalta el hecho de que altos tiempos de cristalizacion le confiere a la zeolita propiedades fisicoquimicas especiales que permiten obtener mayor actividad catalitica comparada con aquellas zeolitas sintetizadas a bajo tiempo de cristalizacion. Por otro lado, el tipo de cation presente en el gel, regula de manera diferente la concentracion de aluminio y por tanto modifica su comportamiento catalitico. Los materiales obtenidos se caracterizaron por diferentes tecnicas analiticas como difraccion de rayos X, analisis termogravimetrico y diferencial, analisis quimico, area BET, desorcion de amoniaco a temperatura programada, resonancia magnetica nuclear 27Al MAS NMR y reduccion a temperatura programada.

Ag+, Cu2+ or Ag+-Cu2+ ion-exchanged nitrate-sodium cancrinite-type zeolites were tested as bactericidal agents against Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). Nitrated-sodium cancrinite was synthesized using solutions of NaOH and NaNO3, and using zeolite X as Al and Si sources under hydrothermal conditions at 80 oC and autogenous pressure during 40 h. Solids were characterized by powder X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and chemical analysis. Then, different masses of these ion-exchanged zeolites were mixed with the microorganisms. Results showed that E. coli was more sensitive than P. aeruginosa, and 2.5 mg of Ag+ or Cu2+-Ag+ cancrinites were enough to inhibit the E. coli growth, while for P. aeruginosa larger amounts of Ag+ (5 mg) and Ag+-Cu2+ (20 mg) of the cancrinites were necessary. Cu-zeolites did not show bactericidal activity. Different treatments times between these microorganisms and the modified zeolites were also investigated. A 20 min treatment was enough to inhibit totally the bacterial growth. As a reference system zeolite A exchanged with these metals was used.

Adobe has been used in construction since the first civilizations in the world, and to improve its mechanicalproperties, organic stabilizers were added. We studied the compressive strength of adobe cubic samples made with soil fromthe Sierra Region of Ecuador and organic stabilizers. Four organic stabilizers were studied: cow manure, nopal sap, strawand bull blood, which were added in specific percentages individually and in combination. Field and laboratory tests werecarried out according to “Proyecto de actualizacion – version 1 de la Norma Peruana E.080 de Noviembre 2013”. The resultsshowed that the four organic stabilizers improve the compressive strength, having an increase from 0.5 to 13.1%. By using10% of cow manure with 20% of bull blood the adobe compressive strength increased 13.1% in relation to the basic adobe.