A new geopolymeric binder from hydrated-carbonated cement

This paper evaluates the use of hydrated Portland cement as the raw material in the production of geopolymers. The silicon and aluminium oxides needed for the geopolymerization process were produced by the carbonation of hydrated Portland cement, which transforms CSH and CAH (Portland cement hydrates) into silica and alumina gels. Hydrated-carbonated Portland cement was alkali activated with a NaOH/waterglass solution. Pastes and mortars were prepared, and micro-structural and mechanical properties were analyzed. It has been noted that geopolymers are mechanically stable and yield compressive strength higher than 10 MPa when mortars are cured at 65 °C for 3 days. The results have shown that there are interesting possibilities for re-using the cement-rich fraction of construction and demolition waste. Alkaline activation of hydrated-carbonated Portland cement could be considered a low CO 2-emission binder. © 2012 Elsevier B.V. All rights reserved.Paya Bernabeu, JJ.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Soriano Martinez, L.; Mitsuuchi Tashima, M. (2012). A new geopolymeric binder from hydrated-carbonated cement. Materials Letters. 74:223-225. doi:10.1016/j.matlet.2012.01.132S2232257

Undamning the Douro river catchment: a stepwise approach for prioritizing dam removal

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime, and degrading the aquatic and riparian habitats. In the present study, which comprised the Douro River basin located in the North of Portugal, the cost-benefit assessment of dams was based upon a balance between the touristic benefits of a dammed Douro, and the ecological benefits of less fragmented Douro sub-catchments. Focused on four sub-catchments (Sabor, Tâmega, Côa and Corgo), a probabilistic stream connectivity model was developed and implemented to recommend priorities for dam removal, where this action could significantly improve the movement of potadromous fish species along the local streams. The proposed model accounts for fish movement across the dam or weir (permeability), which is a novel issue in connectivity models. However, before any final recommendation on the fate of a dam or weir, the connectivity results will be balanced with other important socio-economic interests. While implementing the connectivity model, an inventory of barriers (dams and weirs) was accomplished through an observation of satellite images. Besides identification and location of any obstacles, the inventory comprised the compilation of data on surrounding land use, reservoir water use, characteristics of the riparian gallery, and permeability conditions for fish, among others. All this information was stored in a geospatial dataset that also included geographical information on the sub-catchment drainage network. The linear (drainage network) and point (barriers) source data were processed in a computer program that provided or returned numbers for inter-barrier stream lengths (habitat), and the barrier permeability. These numbers were finally used in the same computer program to calculate a habitat connector index, and a link improvement index, used to prioritize dam removal based upon structural connectivity criteria. The results showed that habitat patch connectivity in the Sabor, Tâmega and Côa sub-catchments is not dramatically affected by the installed obstacles, because most link improvement values were generally low. For the opposite reason, in the Corgo sub-catchment, obstacles may constitute a relatively higher limitation to connectivity, and in this case the removal of eight obstacles could significantly improve this connectivity. Using the probabilistic model of structural connectivity, it was possible to elaborate a preliminary selection of dams/weirs that critically limit stream connectivity, and that will be the focus of field hydraulic characterization to precisely determine fish movement along the associated river stretches. Future work will also include the implementation of a multi-criteria decision support system for dam removal or mitigation of the critical structures, as well to define exclusion areas for additional obstaclesinfo:eu-repo/semantics/publishedVersio

Properties and microstructure of alkali-activated red clay brick waste

Sintered red clay ceramic is used to produce hollow bricks which are manufactured in enormous quantities in Spain. They also constitute a major fraction of construction and demolition waste. The aim of this research was to investigate the properties and microstructure of alkali-activated cement pastes and mortars produced using red clay brick waste. The work shows that the type and concentration of alkali activator can be optimised to produce mortar samples with compressive strengths up to 50 MPa after curing for 7 days at 65 C. This demonstrates a new potential added value reuse application for this important waste material.The authors are grateful to the Spanish Ministry of Science and Innovation for supporting this study through Project GEOCEDEM BIA 2011-26947, and to FEDER funding. They also thank the Institute for Science and Technology of Concrete - ICITECH, for providing the means to carry out this investigation; and Universitat Jaume I, for supporting this research through the research stay granted.Reig Cerdá, L.; Tashima, MM.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Cheeseman, C.; Paya Bernabeu, JJ. (2013). Properties and microstructure of alkali-activated red clay brick waste. Construction and Building Materials. 43:98-106. doi:10.1016/j.conbuildmat.2013.01.031S981064

A utilização do ELISA empregando antígenos homólogos e heterólogos para a detecção de IgG e subclasses (IgG1 e IgG2) no diagnóstico de Leishmaniose visceral canina

Indirect immunofluorescence is the method recommended for the diagnosis of visceral leishmanisis in dogs, however, the accuracy of this technique is low and its use on a large scale is limited. Since ELISA does not present these limitations, this technique might be an option for the detection of IgG or specific IgG1 and IgG2 subclasses. Canine ehrlichiosis is an important differential diagnosis of American Visceral Leishmaniasis (AVL). The present study compared ELISA using Leishmania chagasi and Leishmania braziliensis antigen for the detection of anti-Leishmania IgG and subclasses in serum samples from 37 dogs naturally infected with L. chagasi (AVL) and in samples from four dogs co-infected with L. braziliensis and L. chagasi (CI). The occurrence of cross-reactivity was investigated in control serum samples of 17 healthy dogs (HC) and 35 infected with Ehrlichia canis (EC). The mean optical density obtained for the detection of IgG was significantly higher when L. chagasi antigen was used, and was also higher in subgroup VLs (symptomatic) compared to subgroup Vla (asymptomatic). The correlation between IgG and IgG1 was low. The present results suggest that IgG ELISA using homologous antigen yields the best results, permitting the diagnosis of asymptomatic L. chagasi infection and the discrimination between cases of AVL and ehrlichiosis in dogs.A imunofluorescência indireta é o método recomendado para o diagnóstico de leishmaniose visceral em cães, entretanto, a acurácia dessa técnica é baixa e seu uso em grande escala é limitado. Uma vez que o ELISA não apresenta essas limitações, essa técnica poderia ser uma opção para a detecção de IgG ou subclasses IgG1 e IgG2 específicas. A ehrlichiose canina é um importante diagnóstico diferencial de Leishmaniose Visceral Americana (LVA). O presente estudo comparou o ELISA usando antígenos de Leishmania chagasi e Leishmania braziliensis para a detecção de IgG e subclasses anti-Leishmania em amostras de soro de 37 cães naturalmente infectados com L. chagasi (LVA) e em amostras de quatro cães co-infectados (CI). A ocorrência de reatividade cruzada foi investigada em amostras de soro controle de 17 animais saudáveis (HC) e 35 de infectados por Ehrlichia canis (EC). A média de densidade óptica obtida para a detecção de IgG foi significantemente maior quando o antígeno de L. chagasi foi usado e também mais elevada no subgrupo LVs (sintomático) quando comparado ao subgrupo LVa (assintomático). A correlação entre IgG e IgG1 foi baixa. O presente resultado sugere que ELISA IgG empregando antígeno homólogo, produz os melhores resultados, permitindo o diagnóstico de infecção assintomática por L. chagasi e a discriminação entre casos de LVA e ehrlichiose em cães

Aperiodicity in one-way Markov cycles and repeat times of large earthquakes in faults

A common use of Markov Chains is the simulation of the seismic cycle in a fault, i.e. as a renewal model for the repetition of its characteristic earthquakes. This representation is consistent with Reid's elastic rebound theory. Here it is proved that in {\it any} one-way Markov cycle, the aperiodicity of the corresponding distribution of cycle lengths is always lower than one. This fact concurs with observations of large earthquakes in faults all over the world

New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC)

This paper provides information about the synthesis and mechanical properties of geopolymers based on fluid catalytic cracking catalyst residue (FCC). FCC was alkali activated with solutions containing different SiO 2/Na 2O ratios. The microstructure and mechanical properties were analysed by using several instrumental techniques. FCC geopolymers are mechanically stable, yielding compressive strength about 68 MPa when mortars are cured at 65°C during 3 days. The results confirm the viability of producing geopolymers based on FCC. © 2012 Elsevier B.V. All rights reserved.We acknowledge the Ministerio de Ciencia e Innovacion (MICINN) of the Spanish Government and FEDER funds (MAT-2011-19934 project) and the PROPG-UNESP "Universidade Estadual Paulista Julio de Mesquita Filho", Brazil.Mitsuuchi Tashima, M.; Akasaki, JL.; Castaldelli, V.; Soriano Martínez, L.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Borrachero Rosado, MV. (2012). New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC). Materials Letters. 80:50-52. https://doi.org/10.1016/j.matlet.2012.04.051S50528

Alkali activated materials based on fluid catalytic cracking catalyst residue (FCC): Influence ofSiO2/Na2O and H2O/FCC ratio on mechanical strength and microstructure

Reuse of industrial and agricultural wastes as supplementary cementitious materials (SCMs) in concrete and mortar productions contribute to sustainable development. In this context, fluid catalytic cracking catalyst residue (spent FCC), a byproduct from the petroleum industry and petrol refineries, have been studied as SCM in blended Portland cement in the last years. Nevertheless, another environmental friendly alternative has been conducted in order to produce alternative binders with low CO2 emissions. The use of aluminosilicate materials in the production of alkali-activated materials (AAMs) is an on going research topic which can present low CO2 emissions associated. Hence, this paper studies some variables that can influence the production of AAM based on spent FCC. Specifically, the influence of SiO2/Na2O molar ratio and the H2O/spent FCC mass ratio on the mechanical strength and microstructure are assessed. Some instrumental techniques, such as SEM, XRD, pH and electrical conductivity measurements, and MIP are performed in order to assess the microstructure of formed alkali-activated binder. Alkali activated mortars with compressive strength up to 80 MPa can be formed after curing for 3 days at 65 C. The research demonstrates the potential of spent FCC to produce alkali-activated cements and the importance of SiO2/Na2O molar ratio and the H2O/spent FCC mass ratio in optimising properties and microstructure.Authors would like to thank to the Ministerio de Ciencia e Innovacion (MICINN) of the Spanish Government (BIA2011-26947) and to FEDER for funding, and also to the PROPG - UNESP "Universidade Estadual Paulista Julio de Mesquita Filho'', Brazil.Mitsuuchi Tashima, M.; Akasaki, JL.; Melges, J.; Soriano Martínez, L.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Borrachero Rosado, MV. (2013). Alkali activated materials based on fluid catalytic cracking catalyst residue (FCC): Influence ofSiO2/Na2O and H2O/FCC ratio on mechanical strength and microstructure. Fuel. 108:833-839. https://doi.org/10.1016/j.fuel.2013.02.052S83383910

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio