Numerical interpretation of the coupled hydromechanical behaviour of expansive clays in constant volume column tests

© The authors and ICE Publishing: All rights reserved, 2015.Experimental and numerical studies of the behaviour of expansive clays have been attracting increasing interest, due to their good sealing properties, which render them ideal to be used as engineered barriers (buffers) in both active (e.g. nuclear) and non-active waste disposal facilities. Both large scale and laboratory scaled experiments indicate that the sealing capabilities of the buffer are fundamentally governed by its volumetric behaviour when wetted. In this paper, a constant volume column infiltration test, performed under isothermal conditions on compacted MX80 bentonite, is modelled numerically using the Imperial College Finite Element Program (ICFEP). A modified version of the Barcelona Basic Model is used to simulate the behaviour of the buffer, which is inherently partly saturated. The numerical results agree well with the observed experimental data, especially with regard to the advancement of the wetting front. A detailed interpretation of the computed evolutions with time of stress state, suction and void ratio at different elevations along the samples axis is carried out, providing insight into the complex hydro-mechanical response of the buffer during the experiment. Indeed, even though the overall volume of the sample was kept constant, a region of localised dilation, which induced the contraction of other zones of the material, was observed to advance simultaneously with the wetting front along the height of the soil column

Investigating soil-water retention characteristics at high suctions using Relative Humidity control

A technique for controlling relative humidity (RH) is presented, which involves supplying a sealed chamber with a continuous flow of air at a computer-regulated RH. The desired value of RH is achieved by mixing dry and wet air at appropriate volumes and is measured for servo-control at three locations in the chamber with capacitive RH sensors and checked with a sensitive VAISALA sensor. The setup is capable of controlling RH steadily and continuously with a deviation of less than 0.2% RH. The technique was adopted to determine wetting soil-water retention curves (SWRC) of statically compacted London Clay, under both free-swelling and constant volume conditions. The RH within the chamber was increased in a step-wise fashion, with each step maintained until vapour equilibrium between the chamber atmosphere and the soil samples was established. Independent filter paper measurements further validate the method, while the obtained retention curves complement those available in the literature for lower ranges of suction

Extra-Heavy Crude Oil Viscosity Reduction Using and Reusing Magnetic Copper Ferrite Nanospheres

The main objective of this study is the synthesis, use, and reuse of magnetic copper ferrite nanospheres (CFNS) for extra-heavy oil viscosity reduction. The CFNS were synthesized using a solvothermal method resulting in mean particle size of 150 nm. Interactions of CFNS with the crude oil were evaluated through asphaltene adsorption isotherms, as well as static and dynamic rheology measurements for two cycles at 25◦ C. Adsorption and desorption experiments corroborated that most of the asphaltenes adsorbed can be removed for nanoparticle reuse. During the rheology tests, nanoparticles were evaluated in the first cycle at different concentrations from 300 to 1500 mg/L, leading to the highest degree of viscosity reduction of 18% at 500 mg/L. SiO2 nanoparticles were evaluated for comparison issues, obtaining similar results regarding the viscosity reduction. After measurements, the CFNS were removed with a magnet, washed with toluene, and further dried for the second cycle of viscosity reduction. Rheology tests were performed for a second time at a fixed concentration of 500 mg/L, and slight differences were observed regarding the first cycle. Finally, changes in the extra-heavy oil microstructure upon CFNS addition were observed according to the significant decrease in elastic and viscous moduli

Catheter-associated urinary tract infection in medical patients of a Portuguese hospital: incidence and risk factors

info:eu-repo/semantics/publishedVersio

Neonatal meningitis associated with osteomyelitis and epidural empyema.

Neonatal meningitis is a serious disease with significant mortality and morbidity. Its signs and symptoms are subtle, non-specific, atypical or absent. Cephalohaematoma is frequent in newborns and complications are uncommon, including local infection after haematogenous spread in the setting of bacteraemia or meningitis with a possibility of osteomyelitis, epidural abscess and subdural empyema. We report the case of a late preterm newborn, with an unremarkable pregnancy, born by vacuum-assisted vaginal delivery that presented in the fifth day of life with irritability, fever and grunting. Cerebrospinal fluid and blood cultures were positive for Escherichia coli. The patient had neurological deterioration despite adequate antibiotic therapy and brain MRI showed a right parietal epidural empyema, subcutaneous abscess, osteomyelitis and supratentorial hydrocephalus. The culture of the cephalohaematoma's abscess material was positive for E coli. Antibiotic therapy was continued for 8 weeks. The child, now 2 years old, has spastic tetraparesis with global development delay

Customizing mass housing: a dual computer implementation design strategy based on shape grammars

This research aims at developing a system for automatic generation of designs that allows housing customers to participate in the design of their house by using mass-customization design. The proposed system is based on shape grammars and will allow future owners to acquire houses that fit their needs while simultaneously complying to a language of design (Stiny 1980). Such a system will enable to deliver design solutions with quality (Eloy et al. n.d.) and at affordable prices improving satisfaction of clients and their quality of living. The system encodes knowledge on housing design principles (sizes of rooms, types of rooms and there preferable connections) as well as in the construction techniques that underlies the shape composition principles.info:eu-repo/semantics/publishedVersio

INTERVENÇÕES EM DOENTES COM DEGLUTIÇÃO COMPROMETIDA

INTERVENÇÕES EM DOENTES COM DEGLUTIÇÃO COMPROMETIDA Álvara Silva 1, Ana Taborda1, Hélder Vilarinho1, Inês Rocha1, Olinda Vieira1 1Serviço de Traumatologia Craneo Encefálica (TCE), HSA/CHP. Hospital de Santo António, Centro Hospitalar do Porto (HSA/CHP), Porto. Introdução Deglutição compreende uma actividade neuromuscular complexa, que se inicia de forma consciente e envolve quatro fases: antecipatória, oral, faríngea e esofágica. A disfagia apresenta-se como um sintoma de uma doença, relacionada com alguma parte do tracto digestivo da boca até o estômago podendo originar complicações como a desnutrição, desidratação e respiratórias. Objectivos Identificar e analisar as intervenções mais adequadas às características individuais do doente com deglutição comprometida. Material e Métodos Revisão de literatura através de bases de dados: ISI Knowledge, EBSCO, Oaister, Biblioteca Virtual em Saúde. As palavras-chave utilizadas foram: Intervenções, Disfagia, Reabilitação; Técnicas de Deglutição. Os critérios de inclusão foram: artigos publicados em português e inglês, com acesso livre, texto completo, desde 2005, num total de 208 artigos, tendo sido apenas sido incluídos 8 artigos. Resultados A introdução de alimentos de forma fraccionada, tal como a sua viscosidade (pastosos) são técnicas eficazes para evitar complicações como a desnutrição, desidratação e infecções respiratórias. Efectuando a protusão da língua e abertura da mandíbula, ocorre uma estimulação dos músculos genioglosso e supra hióideos. Em presença de um bolo com consistência mais sólida estes músculos podem tornar-se mais fortes e longos. A deglutição supraglótica, fortalece os músculos do osso hióide, expande a amplitude de movimento do mesmo e aumenta o efeito de protecção da via aérea. A estimulação eléctrica produz efeitos favoráveis na recuperação da disfagia nos doentes após tratamento de cancro de pescoço e da cabeça. Um programa precoce de deglutição de alta intensidade promove a recuperação da função normal da deglutição em doentes com AVC. A administração de líquidos constitui um alto risco para pacientes com a deglutição comprometida. Estímulos mecânico e térmico sobre os pilares do palato e gloso não produzem resposta motora na fase faríngea. Conclusões Nesta revisão da literatura foram analisados vários estudos científicos de diferentes autores, com o objectivo identificar a evidência que forneça um conjunto de intervenções que visem a recuperação de doentes com comprometimento da deglutição. Os trabalhos científicos aqui revistos apontam para necessidade de maior investimento neste âmbito, visto os trabalhos utilizarem amostras heterogéneas, ausência de descrição detalhada das intervenções implementadas, não utilização de critério final a deglutição funcional. Apresentador: Olinda Vieira, Enfermeira, Serviço de Traumatologia Crâneo Encefálica (TCE), HSA/CHP

T cells in sputum of asthmatic patients are activated independently of disease severity or control

Background T cells play an important role in bronchial asthma. Although airway CD4+ T cells have been extensively studied previously, there are hardly any studies relating CD8+ T cell activation and disease symptoms. Objectives The aim of this study was to analyse the association between T cell activation in induced sputum T cells and asthma severity and control; and to evaluate T cell subpopulations in the same subgroups. Methods Fifty allergic asthmatic patients were recruited and lung function testing was performed. Airway cells were obtained by sputum induction via inhalation of hypertonic saline solution. CD3, CD4, CD8, CD28, CD25 and CD69 were studied by flow cytometry in whole induced sputum and peripheral blood cells. Results Total induced sputum T cells and CD8+ T cells had a higher relative percentage of the activation markers CD25 and CD69 in comparison with peripheral blood. In sputum, the relative percentage of CD25 was higher in CD4+ T cells when compared to CD8+ T cells and the reverse was true regarding CD69. However, neither disease severity nor control were associated with the relative percentage of CD25 or CD69 expression on T cells in sputum. Conclusions Both CD4+ and CD8+ T cells are activated in the lungs and peripheral blood of asthmatic patients. However, with the possible exception of CD69+ CD8+ T lymphocytes in the sputum, there is no association between T cell activation phenotype in the target organ and disease severity or control.info:eu-repo/semantics/publishedVersio

Development of a practical heat of hydration model for concrete curing for geotechnical applications

Thermal integrity profiling (TIP) is a common non-destructive technique to evaluate the quality of construction of piles by analysing the temperature fields due to heat of hydration from freshly cast concrete piles. For this process to be accurate, a reliable concrete heat of hydration model is required. This paper proposes a practical and simple to calibrate four parameter model for the prediction of concrete heat of hydration. This model has been shown to be able to reproduce the evolution of heat of hydration measured in laboratory tests, as well as field measurements of temperature within curing concrete piles, as part of a thermal integrity profiling (TIP) operation performed at a site in London. With the simplicity of the model and the small number of model parameters involved, this model can be easily and quickly calibrated, enabling quick predictions of expected temperatures for subsequent casts using the same concrete mix