L'utilisation et l'application de deux matériaux non traditionnels contrastés en remblais et en fondations de chaussées

The increased use of non-traditional materials is driven from multiple perspectives. These include societies’ desire for a more sustainable future, reinforced by legislation, regulation and policy mechanisms to encourage the greater use of such materials. This paper discusses two contrasting materials. Tyre bales are free-draining and lightweight and have been used in road foundations and embankments over soft ground as well as in slope failure repair or slope stabilisation. Electric arc furnace steel slag has been used as a direct replacement for a road embankment and a base course layer, as well as in a rail track. Experience demonstrates that such uses become widespread only when a given environmentally friendly material has a cost advantage and/or a performance benefit, and the material and its use is included in an appropriate standard or specification. It is concluded that the lack of a Quality Protocol is likely to further impede their use.Les progrès vers une utilisation accrue de matériaux non traditionnels sont motivés par un certain nombre de points de vue différents. Le premier d’entre eux est un enjeu de plus en plus important des sociétés pour un avenir plus durable; cela est souvent renforcé par des mécanismes législatifs, réglementaires et politiques de haut niveau visant à encourager une utilisation accrue de ces matériaux. Cet article traite de deux matériaux contrastés. Les balles de pneus sont drainantes et légères et ont été utilisées dans des fondations routières et dans des remblais sur les sols mous ainsi que lors des réparations et stabilisation de talus. Les scories d'aciérie de four à arc électrique ont été utilisées pour remplacer directement un remblai routier et une couche de base, ainsi que sur une voie ferrée. L'expérience montre que ces utilisations ne se généralisent que lorsqu'un matériau respectueux de l'environnement présente un avantage en termes de coûts et / ou un avantage en termes de performances, et que le matériau et son usage sont inclus dans une norme ou une spécification appropriée. Il est conclu que l’absence de protocole de qualité risque d’entraver leur utilisation.The work on tyre bales was variously supported by Veolia Environmental Trust, the Waste Resource Action Programme (WRAP), Inverness & Nairn Enterprise and Transport Scotland. The steel slag studies were financially supported by FCT vy the POCI 2010 program (Project PPCDT/ECM/56952/2004), by the cohesion found FEDER and the company doctoral grant SFRH/BDE/15661/2007

Seed bank and control of Rottboellia exaltata using clomazone alone and in combination with other herbicides.

Objetivou-se, com este trabalho, estudar o banco de sementes e o controle de Rottboellia exaltata L.f. com clomazone, isolado e em associação com outros herbicidas, em áreas de cana-soca com baixa e alta infestação.bitstream/item/131076/1/4466-18529-1-PB-Nubia.pdfOn line

Caracterização da rigidez de misturas betuminosas em ensaios de tracção indirecta por compressão diametral de provetes cilíndricos

As misturas betuminosas utilizadas nas camadas dos pavimentos rodoviários têm comportamento mecânico do tipo visco-elástico. Na prática do dimensionamento, este comportamento é definido pelo módulo de rigidez e pelo coeficiente de Poisson que caracterizam o comportamento elástico linear, mas admitindo que estes parâmetros são dependentes da temperatura e da frequência de aplicação das cargas. A norma europeia EN 12697-26 diz respeito à caracterização da rigidez de misturas betuminosas fabricadas a quente em ensaios com carregamentos repetidos à flexão, tracção indirecta ou tracção directa uniaxial. Esta norma contempla o ensaio de tracção indirecta por compressão diametral de provetes cilíndricos. O Instituto Superior Técnico possui o equipamento NAT que tem permitido o desenvolvimento de estudos baseados nesta técnica de ensaio. O artigo apresenta as principais conclusões de alguns desses estudos relacionadas, essencialmente, com a exactidão do método de ensaio e a sua adequação para caracterizar misturas betuminosas de aplicação corrente na construção e reabilitação das estradas da rede rodoviária nacional. É descrito ainda um modelo de previsão do módulo de rigidez, validado e calibrado para os resultados experimentais obtidos

Consideration of non-linearity of soils behaviour in the numerical modelling of road pavements

O objectivo principal desta comunicação é evidenciar a importância de considerar a nãolinearidade do comportamento dos solos de fundação na modelação numérica dos pavimentos rodoviários, para fins de dimensionamento estrutural. A instrumentação e observação de dois trechos experimentais numa estrada em Lisboa permitiram analisar o comportamento dos solos com esta finalidade. Durante a construção dos aterros foram realizados ensaios de carga com placa e ensaios de carga com pneu. A análise estrutural dos solos da fundação dos pavimentos, pelo método dos elementos finitos, permitiu concluir que a utilização do modelo elástico nãolinear foi a metodologia mais adequada à modelação do comportamento observado durante os ensaios. A consideração de comportamento elástico linear, tão corrente no dimensionamento dos pavimentos, mostrou-se inadequada e com tendência para subestimar a rigidez da fundação.The main objective of this paper is to point out the importance of non linearity of soils foundation behaviour in the road pavement modelling, for structural design purposes. The monitoring of two full-scale instrumented pavements in a road in Lisbon had allowed to this objective. During the test sections constructions, plate load tests and wheel load tests were carried out. The structural analysis of soils behaviour, by the finite elements method, allowed to conclude that the best adjustment to the experimental results was performed with the non-linear elastic model. The elastic linear behaviour, so worldwide used in pavements design, has shown inadequate and with trend to under predict foundation stiffness

Stability maps for the 5/3 mean motion resonance between Ariel and Umbriel with inclination

The evolution of the five largest satellites of Uranus during the crossing of the 5/3 mean motion resonance between Ariel and Umbriel is strongly affected by chaotic motion. Studies with numerical integrations of the equations of motion and analysis of Poincar\'e surface sections provided helpful insights to the role of chaos on the system. However, they lack of a quantification of this chaos in the phase-space. Here, we construct stability maps using the frequency analysis method. We determine that for low energies (small eccentricity and/or inclinations), the phase-space is mainly stable. As the energy increases, the chaotic regions replace the stable motion, until only small, localized libration regions remain stable.Comment: arXiv admin note: text overlap with arXiv:2305.0879

A review of sustainable approaches in transport infrastructure geotechnics

Transportation geotechnics associated with constructing and maintaining properly functioning transportation infrastructure is a very resource intensive activity. Large amounts of materials and natural resources are required, consuming proportionately large amounts of energy and fuel. Thus, the implementation of the principles of sustainability is important to reduce energy consumption, carbon footprint, greenhouse gas emissions, and to increase material reuse/recycling, for example. This paper focusses on some issues and activities relevant to sustainable earthwork construction aimed at minimising the use of energy and the production of CO2 while improving the in-situ ground to enable its use as a foundation without the consumption of large amounts of primary aggregate as additional foundation layers. The use of recycled materials is discussed, including steel slag and tyre bales, alongside a conceptual framework for evaluating the utility of applications for recycled materials in transportation infrastructure.This work is financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-00763

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

Risk factors for Salmonella sp. in pig lymph nodes in Portuguese abattoirs

Salmonella is one of the major causes of food borne disease in the European Union (EU). Some of the human cases are related to pork products. An EU baseline survey to assess the Salmonella pork prevalence was performed. Mesenteric lymph nodes were cultured and Salmonella sp. isolates were serotyped. Data concerning the animal and the slaughterhouse was also collected. The aim of the present study was to search for potential risk factors to the presence of Salmonella sp. in pigs lymph nodes in Portugal and to search for differences in the risk profile between groups of serotypes. The data was analysed using a Bayesian approach to incorporate the hierarchical structure of the data (samples nested in slaughterhouses). Two models were analysed: a binomial (presence/absence of Salmonella sp.) and categorical model (absence of Salmonella sp., serotype Typhimurium or serotype 1,4,[5],12:i:-, other serotypes). A total number of 659 samples were tested, belonging to 36 slaughterhouses. Around 23.7% of the samples were positive for Salmonella sp.. In the binomial model a significant association was found for region of the slaughterhouse - Lisbon and Tagus Valley Region with lower risk compared to the Centre Region (OR=0.36). In the categorical model a significant association for category Typhimurium or 1,4,[5],12:i:- was found for the variable hour when the sample was taken - afternoon with lower risk compared to morning (OR=0.20). The association found for the slaughterhouse region should be a matter of furthers studies to evaluate the hygiene practices in the slaughterhouses of that region

Risk associations for presence of Salmonella sp. in pen samples of breeding pigs in Portugal using binomial multilevel models

As Salmonella is one of the major causes of food-borne disease in the European Union (EU), EU approved legislation to achieve a reduction of the prevalence of this agent in the pig sector. To set the target for this reduction in each country it was decided to carry out baseline surveys in the EU to estimate the prevalence of the agent. The dataset analyzed in this work refers to the cross sectional baseline survey on the prevalence of Salmonella in breeding pigs in Portugal. A total of 1670 pen fecal samples from 167 herds were submitted to fecal culture

Probing the Kinetic Stabilities of Friedreich’s Ataxia Clinical Variants Using a Solid Phase GroEL Chaperonin Capture Platform

Numerous human diseases are caused by protein folding defects where the protein may become more susceptible to degradation or aggregation. Aberrant protein folding can affect the kinetic stability of the proteins even if these proteins appear to be soluble in vivo. Experimental discrimination between functional properly folded and misfolded nonfunctional conformers is not always straightforward at near physiological conditions. The differences in the kinetic behavior of two initially folded frataxin clinical variants were examined using a high affinity chaperonin kinetic trap approach at 25 °C. The kinetically stable wild type frataxin (FXN) shows no visible partitioning onto the chaperonin. In contrast, the clinical variants FXN-p.Asp122Tyr and FXN-p.Ile154Phe kinetically populate partial folded forms that tightly bind the GroEL chaperonin platform. The initially soluble FXN-p.Ile154Phe variant partitions onto GroEL more rapidly and is more kinetically liable. These differences in kinetic stability were confirmed using differential scanning fluorimetry. The kinetic and aggregation stability differences of these variants may lead to the distinct functional impairments described in Friedreich’s ataxia, the neurodegenerative disease associated to frataxin functional deficiency. This chaperonin platform approach may be useful for identifying small molecule stabilizers since stabilizing ligands to frataxin variants should lead to a concomitant decrease in chaperonin binding