3,805 research outputs found
Fetopathy associated with exposure to angiotensin converting enzyme inhibitors
Angiotensin Converting Enzyme Inhibitors (ACEI) are commonly used antihypertensive drugs, although contraindicated during pregnancy by fetopathy association such as renal dysgenesis, oligohydramnios, hipocalvaria, pulmonary hypoplasia, intrauterine growth restriction, and neonatal anuric renal failure. The authors present a clinical report of a child that developed neonatal anuric renal failure with peritoneal dialysis support by an in uterus exposure to ACEI with very good recovery. This case and literature review states the need to avoid ACEI prescription to Young women and it's suspension as soon as possible during pregnancy
Geomechanical parameters updating in an underground work
In geotechnical engineering, and in the particular case of underground works, a great number of uncertainties
arise due to the lack of knowledge of the involved formations and their variability. Geomechanical parameters are one of the
main issues in the underground works design. In the initial stages, the available information about the rock masses
characteristics is scarce. As the project advances to other stages more and more information from different sources becomes
available and can be used for updating the geomechanical model. Bayesian methodologies use probability as the main tool
to deal with uncertainty and manage to reduce it using new data via the Bayes theorem. In this work, a part of a developed
Bayesian framework to the updating of the deformability modulus (E) in an underground structure is presented. Assuming E
as a random variable, data from LFJ tests is used to obtain a posterior and less uncertain distribution of E. This approach led
to good results and considerable uncertainty reduction and increased reliability. The developed Bayesian framework
constitutes a rational and structured way of dealing with data with different sources and uncertainty levels.Fundação para a Ciência e a Tecnologia (FCT) - projecto POCI/ECM/57495/2004 entitled “Geotechnical Risk inTunnels for High Speed Trains”
Determination of geomechanical parameters using a KBS system and application to an underground station
In this paper a KBS computational system, designated by GEOPAT, for the calculation of geomechanical parameters for modelling underground structures in rock and soil formations is presented. To congregate the specialists' knowledge in rock and soil domains, and in particular in the tunnel engineering, causal nets have been established for decision support. GEOPAT determines the parameters for rock and soil formations, as well as heterogeneous rock formations. The developed GEOPAT system was applied to a large underground station in urban environment, excavated in granite formations, in order to obtain the deformability and strength parameters of the surrounding rock masses. Numerical models were developed considering either the obtained geomechanical parameters using artificial intelligence techniques or the parameters used in design. The numerical results obtained with the two sets of parameters are compared, as well as with the monitoring results. Some conclusions are drawn
Determinação de parâmetros geomecânicos em formações rochosas e maciços heterogéneos
Neste trabalho apresentam-se metodologias desenvolvidas para a obtenção de parâmetros geomecânicos em formações rochosas, incluindo-se a situação de maciços
heterogéneos. No caso das formações rochosas, a quantificação desses parâmetros é analisada com base nos principais ensaios in situ e de laboratório e com recurso aos sistemas empíricos,
com destaque para os sistemas RMR (Rock Mass Rating), Q e GSI (Geological Strength
Index). No que se refere aos maciços rochosos claramente heterogéneos como acontece nas formações graníticas da região do Porto, faz-se uma referência às possíveis abordagens do problema, identificando-se, contudo, ainda a necessidade de investigação neste domínio
Use of aI techniques and updating in geomechanical characterisation
Fundação para a Ciência e a Tecnologia (FCT) - projecto POCI/ECM/57495/2004 "Geotechnical Risk
in Tunnels for High Speed Trains
Determination of geomechanical parameters in granite formations using a knowledge based system
Nesta comunicação apresenta-se um sistema computacional para a obtenção de parâmetros
geomecânicos para a modelação de túneis em formações graníticas. Este sistema, designado GEOPAT, utiliza técnicas de inteligência artificial baseadas em conhecimento (KBS -
Knowledge Based System). Para este efeito, estabeleceram-se redes causais, com vista a
congregar o conhecimento de especialistas nos domínios das rochas e dos solos em geral e no domínio da engenharia de túneis em particular para o apoio à decisão. O GEOPAT determina os parâmetros para formações rochosas, terrosas e heterogéneas. As interfaces com o utilizador são interactivas e o sistema recorre a plataformas de Visual Basic, KAPPA-PC e Excel.In this paper a computational system for the calculation of geomechanical parameters for
tunnels modelling in granite formations is presented. This system called GEOPAT uses artificial
intelligence techniques (KBS systems). To congregate the specialists' knowledge in rocks and
soils domains and in particular in the tunnel engineering domain causal nets has been
established for decision support. GEOPAT determines the parameters for rock masses, soils and
heterogeneous rock formations. The interfaces are interactive and the system uses Visual Basic,
KAPPA-PC and Excel platforms.Sociedade Portuguesa de Geotecnia (SPG)Associação Brasileira de Mecânica dos Solos e Engenharia GeotécnicaUniversidade de Aveiro. Secção Autónoma de Engenharia Civi
Advanced tools and techniques to add value to soil stabilization practice
The aim of this paper is to demonstrate the advanced tools and techniques used for adding value to the soil stabilization practice. The tools presented involve advanced laboratory tests and modeling using codes and soft computing to evaluate the mechanical behavior of stabilized soils with cement, ranging from short-term to long-term behavior. More precisely, these tools are able to: 1. Predict the mechanical behavior of the stabilized soils over time from data obtained in the early ages saving time in laboratory tests; 2. Predict the mechanical behavior of the stabilized soils over time based on basic parameters of soil type and binder using historical accurate data, avoiding mechanical laboratory tests. 3. Incorporate the serviceability limit state concept in a novel proposal to estimate the design modulus in function of the uniaxial compressive strength and the strain level, making more economic and sustainable geotechnical solutions.This work was supported by FCT—‘‘Fundação para a Ciência e a Tecnologia’’, within ISISE, project UID/ECI/04029/2013 and through the post doctoral Grant fellowship with reference SFRH/BPD/94792/2013. This work was also partly financed by FEDER funds through the Competitivity Factors Operational Programme—COMPETE and by national funds through FCT within the scope of the project POCI-01-0145-FEDER-007633.info:eu-repo/semantics/publishedVersio
Prediction of geomechanical parameters using a KBS system. Application to two case studies of underground structures
In this paper the knowledge based system called GEOPAT is presented. The system calculates geomechanical parameters for modelling underground structures in rock, soil and heterogeneous formations. Specialists knowledge in this field was congregated and organized in causal nets. GEOPAT is still under developmentand aims to be an important tool for decision support. Nevertheless GEOPAT was already applied to some underground structures with success. In this work two of these applications are presented. The first is a largeunderground station of Metro of Porto and the last is the powerhouse complex composed by two caverns ofthe Venda Nova II hydroelectric scheme. Both structures were built in a granite rock mass. The geomechani-cal parameters were obtained using GEOPAT based on some information gathered in the field. Numerical models were developed and the results were compared with the monitored values. They showed in general a good agreement however it is still necessary to improve and increase the knowledge inside the system
Modelação numérica de uma central hidroeléctrica subterrânea utilizando parâmetros geomecânicos obtidos através de técnicas de inteligência artificial
No Norte de Portugal está a ser construído um grande complexo hidroeléctrico subterrâneo como reforço de potência de um sistema hidroeléctrico existente desde 1951. Este novo complexo inclui um circuito hidráulico com 4,4 km de comprimento e duas cavernas para o conjunto da central. Os parâmetros geomecânicos das formações graníticas interessadas foram obtidos através de um programa chamado GEOPAT, que utiliza técnicas de inteligência artificial. Permite calcular parâmetros geomecânicos para a modelação do comportamento estrutural das obras subterrâneas. Foram desenvolvidos modelos numéricos para a análise do comportamento das cavernas do complexo da central utilizando parâmetros obtidos pelo GEOPAT. Os valores calculados a partir dos modelos numéricos foram comparados com os correspondentes valores observados apresentando na globalidade uma boa concordância
Desenvolvimento de sistemas de inteligência artificial para análise de risco em túneis
O presente trabalho descreve sistemas computacionais que estão em fase de
desenvolvimento e aperfeiçoamento e que servirão para a análise de risco dos túneis da rede de
comboios de alta velocidade a ser construída em Portugal. Um dos sistemas, designado GEOPAT,
serve para prever parâmetros geomecânicos para a modelação de obras subterrâneas. Neste trabalho
serão apresentadas duas aplicações que já foram efectuadas nesta fase de desenvolvimento do
sistema a duas importantes obras subterrâneas construídas no Norte de Portugal. O outro sistema,
designado MATUF, está vocacionado para o apoio a operações de manutenção e inspecção dos
túneis
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