Nucleation kinetics of crystalline phases from a kaolinitic body used in the processing of red ceramics

The crystallization kinetics of red ceramic raw material from the western part of São Paulo State, Brazil, was examined by differential thermal analysis (DTA) and X-ray diffraction (XRD). The chemical composition of the clay sample was determined by X-ray fluorescence (XRF). Non-isothermal crystallization kinetic methods have been applied to the study of the mechanism of crystallization in this kaolinitic material. The exothermic peak shifted to higher temperatures (945 to 974 °C) with increasing heating rate (10 to 50 °C/min). The average activation energies determined by the Kissinger method (787 ± 85 kJ/mol) and the Ligero method (721 ± 32 kJ/mol) are in agreement. The Avrami constant n obtained by the Ligero method and the m parameter (Matusita method) values were between 1 and 1.5, which indicate a three-dimensional crystal growth with polyhedral morphology and surface nucleation as the dominant mechanism. X-ray diffraction data indicate that this activation energy is not associated with the crystallization of mullite. Scanning electron microscopy (SEM) images of fired (1000 and 1190 °C) samples show their densification during the sinterization process.The authors thank FUNDUNESP and FAPESP (2008/04368-4) for financial support of this work. We also are grateful to PROPE/UNESP/SANTANDER for Dr. Teixeira's post-doc scholarship in MadridPeer reviewe

Valorization of sugarcane bagasse ash: Producing glass-ceramic materials

Some aluminosilicates, for example mullite and wollastonite, are very important in the ceramic and construction industries. The most significant glass-ceramic for building applications has wollastonite as the main crystal phase. In this work we report on the use of sugarcane bagasse ash (SCBA) to produce glass-ceramics with silicates as the major crystalline phases. The glasses (frits) were prepared by mixing ash, limestone (calcium and magnesium carbonates) and potassium carbonate as the fluxing agent. X-ray fluorescence was used to determine the chemical composition of the glasses and their crystallization was assessed by using thermal analysis (DTA/DSC/TGA) and X-ray diffraction. The results showed that glass-ceramic material can be produced with wollastonite as the major phase, at a temperature lower than 900 °C.We are grateful to PROPE/UNESP/SANTANDER for the post-doctoral scholarship awarded to Dr. Teixeira, to FAPESP (2008/04368-4) for financial support of this project and also to FUNDUNESP for financial aid.Peer reviewe

Characterization of a wollastonite glass-ceramic material prepared using sugar cane bagasse ash (SCBA) as one of the raw materials

Glass-ceramic material prepared with sugar cane bagasse ash as one of the raw materials was characterized to determine some important properties for its application as a coating material. X-ray diffraction patterns showed that wollastonite-2M (CaSiO3) was the major glass-ceramic phase. The Rietveld method was used to quantify the crystalline (60 wt.%) and vitreous (40 wt.%) phases in the glass-ceramic. The microstructure (determined by scanning electron microscopy) of this material had a marble appearance, showing a microporous network of elongated crystals with some areas with dendritic, feather-like ordering. Microhardness data gave a mean hardness value of 564.4 HV (Vickers-hardness), and light microscopy disclosed a greenish brown colored material with a vitreous luster.The authors acknowledge the financial support provided through the project TRISOLCOOLAB (ENE2010-20650-CO2-01-02), Ministerio de Ciencia e Innovación of the Spanish government for facilitating the presentation of this work in CRYSTALLIZATION 2012. Also, the authors thank FAPESP (2008/04368-4) for financial support of this project and FUNDUNESP (01090/2011-DFP) for financial aid.Peer reviewe

Segredos de liquidificador: conhecimento e práticas de sexo seguro por Pessoas Vivendo com HIV/AIDS

http://dx.doi.org/10.5216/ree.v14i2.12647 O presente estudo foi realizado no hospital Dia do Hospital Universitário Professor Alberto Antunes em Maceió, Alagoas, com o objetivo de analisar o conhecimento e identificar as práticas de sexo seguro das Pessoas Vivendo com HIV.  Trata-se de pesquisa descritiva de abordagem qualitativa, realizada por meio de entrevista semiestruturada com treze pessoas. Os dados coletados foram organizados e analisados com base na análise temática. Os resultados apontaram para duas temáticas: A percepção do viver e conviver com HIV e A contradição entre o conhecimento e as práticas de sexo seguro. A análise evidenciou a situação de vulnerabilidade relacionada à condição de soropositividade e de marginalidade social, dificultando a convivência com o vírus e repercutindo em práticas sexuais desprotegidas. Discute-se a necessidade dos serviços desenvolverem estratégias educativas e preventivas voltadas para as pessoas que convivem com o vírus, com valorização da subjetividade em seu contexto sociocultural

Proposal of an Accessible Cabin Concept on Regional Aviation for Passengers with Disabilities

Despite a global increase in the number of passengers with disabilities on regional aviation, most aircraft cabins are still not adequately equipped to provide sufficient comfort to this public, making the travel experience much less attractive. In order to investigate how airlines and aircraft manufacturers could improve the cabin’s accessibility, this study aims to investigate solutions and systems available in the market to propose an accessible cabin concept for regional aviation. This research is part 2 of a two-part series that aims to apply a methodology inspired by Design Thinking Tools such as persona mapping to suggest improvements for the experience of passengers with disabilities. To this end, potential systems were evaluated and a cabin concept was proposed. It was noted that for passengers with sensory impairments, it is possible to improve their experience without major cabin modifications. However, research on their needs is limited and there are few solutions on the market targeting this audience. Conversely, passengers with mobility restrictions pose more complex challenges. Finally, the proposed accessible cabin concept demonstrates the potential to enhance the flight experience for passengers with special needs, potentially increasing their market share and overall satisfaction

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV