Performance of Low-Volume Roads with Wearing Course Layer of Silty Sandy Soil Modified with Rice Husk Ash and Lime

[EN] Rice husk ash (RHA) is a by-product of rice milling. Its use as soil stabilizer is a way to replace the final disposal with environmental benefit. However, RHA is not cementitious itself but when mixed with lime forms cements which improve the soil properties. A research of performance of a silty sandy soil modified with RHA and lime as wearing course layer of low-volume roads was conducted through two full-scale test sections with different pavements built in Artigas, northern Uruguay. The alkaline reactivity of RHA is low because the husk burning is not controlled. The soil-RHA-lime mix design was conducted according to the Thompson’s Method. The pavement test sections were monitored through deflection measures by Benkelman beam and observations of surface condition. The deflections decreased over time in both test sections due to the development of cementation of the study materials. After one year, the dust emission was reduced, the wet skid resistance of pavement surfaces improved and there was not rutting. The researched pavements have had a good performance under the existing traffic and environmental conditions, demonstrating that wearing course layer of silty sand modified with RHA and lime is an alternative to improve the condition of low-volume roads and to replace the final disposal of RHA, with environmental, social and economic benefits.DOI: http://dx.doi.org/10.4995/CIT2016.2016.3451http://ocs.editorial.upv.es/index.php/CIT/CIT2016Behak Katz, L.; Musso Laespiga, M. (2016). Performance of Low-Volume Roads with Wearing Course Layer of Silty Sandy Soil Modified with Rice Husk Ash and Lime. Editorial Universitat Politècnica de València. 630-637. https://doi.org/10.4995/CIT2016.2015.3451OCS63063

Evaluación de la conductividad hidráulica de suelos arcillosos para barreras impermeables de rellenos sanitarios

Los suelos arcillosos son usados como barrera de arcilla compactada (CCL) en obras de ingeniería como presas de tierra, lagunas de tratamiento de efluentes y en rellenos sanitarios. Las normativas ambientales de diferentes países coinciden en la necesidad de baja conductividad hidráulica (< 10-9 m/s) de las barreras de fondo. Esto puede ser cumplido usando una barrera de arcilla compactada (CCL) o de geocompuestos de bentonita (GCL). El objetivo de este trabajo es comparar el comportamiento hidráulico de CCLs y GCL. Fueron analizados suelos arcillosos de origen sedimentario de la cuenca de Paraná, de formaciones del Pérmico-Triásico con diferencias en su composición granulometría y mineralógica. Las unidades geológicas elegidas fueron la Fm Corumbataí (San Pablo, Brasil) y la Fm. Yaguarí (Uruguay). El GCL estudiado es compuesto por bentonita sódica y es fabricado por la empresa Ober de Brasil. La Fm. Corumbataí está compuesta por illita, la Fm. Yaguarí por esmectita cálcica y el GCL por esmectita sódica. A pesar de las diferencias, todos los suelos estudiados cumplen la condición de tener conductividad hidráulica menor a 10-9 m/s, exigida por diferente agencias de protección ambiental para barreras impermeables. Los menores valores de conductividad hidráulica se obtuvieron en el GCL, los valores intermedios en la Fm. Yaguarí y los valores mayores en la Fm. Courumbataí

Many-body localization in large-N conformal mechanics

In quantum statistical mechanics, closed many-body systems that do not exhibit thermalization after an arbitrarily long time in spite of the presence of interactions are called as many-body localized systems, and recently have been vigorously investigated. After a brief review of this topic, we consider a many-body interacting quantum system in one dimension, which has conformal symmetry and integrability. We exactly solve the system and discuss its thermal or non-thermal behavior.Comment: 12 pages, 2 figures, Contribution to Proceedings of the Workshop "Quantum Theory and Symmetry (QTS) 10 and Lie Theory and Its Applications in Physics (LT) 12

The methodology of the GUSTO cohort study: a novel approach in studying pediatric allergy

Growing Up in Singapore Towards healthy Outcomes (GUSTO) is Singapore's largest birth cohort study to date. The main aim of GUSTO is to evaluate the role of developmental factors in the early pathways to metabolic compromise. Detailed data is collected for a range of environmental exposures in the parents and offspring, and allergic disorders are among a number of outcomes assessed in infancy and childhood. Under the Allergy domain of GUSTO, this integrated study will describe the epidemiology of allergic manifestations and different phenotypes in the Asian context and help shed light on the association of metabolic disease to allergy. Epigenetic mechanisms and associations with other childhood disorders will also be explored. The aim of this report is to focus on methodology of GUSTO, and to suggest similar approaches (i.e., integrated cohort studies on pediatric allergy) worldwide. Recruitment commenced in 2009 with a cohort of 1,163 pregnant mothers in their first trimester. The mothers and children were followed throughout pregnancy and follow-up will continue until the child reaches 3 years of age. Preliminary results showed that 39.8% of the mothers had a personal history of having at least one allergic disease, which included asthma, eczema and allergic rhinitis. Further data collection and analyses are still ongoing. Allergy is a complex spectrum of disorders with numerous poorly-understood aspects. The ongoing GUSTO cohort study, with its longitudinal design and multi-disciplinary nature, may provide new insights into developmental influences on allergy. As a Singapore-based study, it will be the first integrated allergy cohort in Southeast Asia, of which recruitment started during pregnancy

La búsqueda de la identidad en el período 1975-1983

A partir del análisis de resoluciones y expedientes judiciales conservados en el Archivo General de los Tribunales de Córdoba, mediante el relevamiento y sistematización de los procesos de guardas y adopciones tramitados entre 1975 y 1983 en los Juzgados de Menores y Juzgados Civiles, el proyecto se propone: identificar casos potenciales de apropiación de hijos de personas víctimas del Terrorismo de Estado, y elaborar una base de datos que contribuya a dar respuesta a las consultas sobre identidad presentadas ante el Poder Judicial de Córdoba. Es un trabajo cuya mirada se centra en la escena judicial de la época del “Proceso de Reorganización Nacional” con el propósito de colaborar en la promoción de los derechos humanos y la restitución de derechos vulnerados.Fil: Bonzano, María de los Ángeles. Universidad Católica de Córdoba. Facultad de Derecho y Ciencias Sociales; Argentin

La búsqueda de la identidad en el período 1975-1983

A partir del análisis de resoluciones y expedientes judiciales conservados en el Archivo General de los Tribunales de Córdoba, mediante el relevamiento y sistematización de los procesos de guardas y adopciones tramitados entre 1975 y 1983 en los Juzgados de Menores y Juzgados Civiles, el proyecto se propone: identificar casos potenciales de apropiación de hijos de personas víctimas del Terrorismo de Estado, y elaborar una base de datos que contribuya a dar respuesta a las consultas sobre identidad presentadas ante el Poder Judicial de Córdoba. Es un trabajo cuya mirada se centra en la escena judicial de la época del “Proceso de Reorganización Nacional” con el propósito de colaborar en la promoción de los derechos humanos y la restitución de derechos vulnerados.Fil: Bonzano, María de los Ángeles. Universidad Católica de Córdoba. Facultad de Derecho y Ciencias Sociales; Argentin

Development and Evaluation of a Sensitive PCR-ELISA System for Detection of Schistosoma Infection in Feces

Schistosomiasis is a neglected disease caused by worms of the genus Schistosoma. The transmission cycle requires contamination of bodies of water by parasite eggs present in excreta, specific snails as intermediate hosts and human contact with water. Fortunately, relatively safe and easily administrable drugs are available and, as the outcome of repeated treatment, a reduction of severe clinical forms and a decrease in the number of infected persons has been reported in endemic areas. The routine method for diagnosis is the microscopic examination but it fails when there are few eggs in the feces, as usually occurs in treated but noncured persons or in areas with low levels of transmission. This study reports the development of the PCR-ELISA system for the detection of Schistosoma DNA in human feces as an alternative approach to diagnose light infections. The system permits the enzymatic amplification of a specific region of the DNA from minute amounts of parasite material. Using the proposed PCR-ELISA approach for the diagnosis of a population in an endemic area in Brazil, 30% were found to be infected, as compared with the 18% found by microscopic fecal examination. Although the technique requires a complex laboratory infrastructure and specific funding it may be used by control programs targeting the elimination of schistosomiasis

Consenso intersocietario para el tratamiento de la obesidad en adultos en Argentina

La obesidad es una enfermedad crónica que genera altos costos en salud, cuyo tratamiento, en ocasiones, no se aborda o se lo hace de forma inadecuada, y muchas veces no se basa en la evidencia disponible. Es por ello que, a partir de una iniciativa de la Sociedad Argentina de Nutrición, diferentes sociedades científicas se reunieron con el objetivo de construir un documento actualizado, basado en una metodología científica, que aporte al mejor tratamiento de las personas que viven con obesidad en Argentina. Este es el primer Consenso Intersocietario para el tratamiento de la Obesidad en adultos en Argentina a partir del cual se obtuvieron recomendaciones para la práctica clínica basadas en la evidencia científica. Es una necesidad primordial contar con herramientas, adecuadas a la realidad local y consensuadas por expertos de distintas disciplinas

Expansive sediments of Libertad Formation (Quaternary) research: engineering geological mapping and evaluate methodology in suburban area of Montevideo city, Uruguay

O estudo do fenômeno de expansão em solos argilosos tem-se restringido, na maioria das vezes, a estudos laboratoriais referentes ao comportamento mecânico do solo e as correlações com as propriedades índices e as classificações geotécnicas. Poucos são os estudos na área de mapeamento geotécnico em média e grande escala, existindo um vazio nas metodologias de mapeamento geotécnico no que se refere a esta classe de solos. Durante o desenvolvimento desta pesquisa sobre as características expansivas da Fm. Libertad, Quaternário (Uruguai), foram combinados os produtos obtidos das técnicas de mapeamento com os propriedades identificadas nos ensaios de caracterização e as medidas de expansão. A técnica de avaliação de terreno usando Landforms para separar unidades homogêneas, resultou em um grande auxílio permitindo direcionar os trabalhos e observações de campo e diminuir o numero de amostras a serem coletadas. O ensaio de caracterização da Capacidade de Troca Catiônica (CTC) da fração argila, usando a técnica de Azul de Metileno, mostrou-se coincidente com a identificação de argilo-minerais usando Difração de Raios X (DRX). Esses dados, associados aos valores de Pressão de Expansão e Expansão livre de amostra indeformadas, com umidade natural e secas ao ar, e de amostras compactadas com diferentes massas específicas seca (pd) e umidade constante (w=15%) permitiram identificar unidades com diferentes potenciais de expansão na Fm. Libertad. A combinação desses dados permitiu a produção da Carta de Potencial de Expansão do Solos, numa região de desenvolvimento urbano no Município de Montevidéu, Uruguai. Este documento fornece aos planejadores do uso e ocupação da área o conhecimento dos diferentes graus de restrição que devem ser levados em conta devido à presença de solos potencialmente expansivos. Elaborou-se uma proposta metodológica para a execução de trabalhos de mapeamento geotécnico de solos expansivos.The swelling phenomenon of the clay soils has been studied mainly in laboratory with the objective of undestand the behavior of the soil and the correlations with the index properties and with the geotechnical classifications. In Engineering Geotechnical Mapping there is a lack of methodology about swell soil mapping in medium or large scale. In this research the swelling characteristics of the Libertad Formation (Uruguay) were studied by combination of the information obtained in the Engineering Geotechnical Mapping (scale 1:10.000) and the soil properties identified in the characterization and swelling tests. The technique of land evaluation using Landforms to separate homogeneous units, it resulted in a great aid allowing to guide the works and field observations and to reduce the number of samples to be collected. The characterization tests of cationic exchange capacity (CEC) of the clay, using the technique of adsorption of methilene blue, it was shown coincident with the identification of clay using X-Ray Diffraction (XRD). The swelling potentials of the Libertad Formation were determined based in the information of the values of swelling pressure and free swelling from undisturbed samples, both with natural moisture contents and air dried, besides the samples compacted with different apparent specific gravity (pd) and with constant moisture content (w= 15%). This procedure allowed the production of the Swelling Potential Chart of the soil in an suburban area of Montevideo City, Uruguay. This document can supply the information to the management of the area taken in account the different swelling potential of the soils. Finally it is presented a methodology to carry out Engineering Geological Mapping of the swelling soils

Solute transport through compacted clay liner (CCL) and geosynthetic clay liner (GCL): direct and coupled flux and membrane behavior

Neste trabalho foi analisado o comportamento de um solo argiloso compactado (CCL) da Fm. Corumbataí e de um geocomposto bentonítico (GCL) composto por bentonita \'NA\', frente a gradientes hidráulicos e químicos. As propriedades físicas e mineralógicas dos solos foram avaliadas, bem como determinados em ensaios de adsorção em lote os parâmetros das isotermas de Freundlich e Langmuir. Foi desenvolvido um equipamento para avaliar o comportamento membrana e poder calcular o coeficiente de eficiência químico-osmótico (\'ômega\') em ensaio de difusão-membrana. Os ensaios de advecção foram executados com o equipamento já existente no departamento de Geotecnia. Em todos os ensaios foram utilizadas soluções monoiônicas de \'KCL\' e \'CU\'CL IND.2\' 2\'H IND.2\'O\'. O valor do factor de retardamento Rd determinado no ensaio em lote (batch test) foi maior que o Rd medido no ensaio de advecção, enquanto que, no ensaio de difusão-membrana, obteve-se o menor valor de Rd. Tanto o GCL quanto o CCL apresentaram comportamento membrana e geração de pressão osmótica para as soluções utilizadas. No entanto, com a solução de \'K POT.+\' as diferenças de pressão se mantiveram durante o ensaio, enquanto que no caso da solução de \'CU POT.+2\' a pressão induzida no corpo de prova do CCL e do GCL tem um pico e logo diminue até zero. O GCL teve um aumento na condutividade hidráulica, no ensaio de advecção, quando permeado com solução de \'CU POT.+2\'. Este comportamento é atribuído ao colapso da dupla camada difusa das partículas de argila. O CCL não apresentou este comportamento. Os resultados deste trabalho sugerem que o CCL da Fm. Corumbataí tem melhor desempenho como barreira que o GCL, nas condições de laboratório e para as soluções usadas.In this research the behavior of a compacted clayey liner (CCL) of Corumbataí Fm. and a geosynthetic clay liner (GCL) containing \'NA\'-bentonite, was evaluated in presence of hydraulic and chemical gradients. Physical and mineralogical properties of the soils were determined and batch tests were executed to obtain the adsorption parameters of the Freundlich and Langmuir models. A laboratory apparatus was developed for assessment of the membrane behavior allowing determining the chemico-osmotic efficiency coefficient (\'ômega\') in diffusion-membrane test. The advection test was carried out with existent equipment in geotechnical department. Both tests were performed with single salt \'KCL\' and \'CU\'CL IND.2\' 2\'H IND.2\'O\' solutions. The measured value of the retardation factor (Rd) for the batch test is bigger than the Rd measured in advection test while in the diffusion-membrane test, the Rd obtained is the smallest. Both GCL and the CCL exhibit membrane behavior and they generate osmotic pressure with both solutions. However with \'KCL\' solution the difference of pressure are maintained during the test, while in the case of \'CU POT.+2\' solution the induced pressure across the specimen of CCL and GCL have a peak to after decrease to zero. The GCL had an increase in the hydraulic conductivity for a \'CU POT.+2\' solution in the advection test. This behavior is attributed to the collapse of the diffuse double layers of clay particles. The CCL did not exhibit this behavior. The results of this study suggest that the CCL of Corumbataí Fm. has a better performance as clay barrier tha the GCL, considering the solutions used and in the laboratory conditions