Tribo-Corrosion behaviour of TiCxOy thin films in bio fluids

In recent years, the development of thin film systems for decorative applications has attracted significant attention in scientific research. These decorative coatings require, not only an attractive appearance for market applications, but also an ability to protect the surface underneath. Because of this, corrosion, wear and their combined effects (termed tribo-corrosion) are particularly important for lifetime prediction. The tribo-corrosion behaviour of a range of single layered titanium oxycarbide, TiCxOy,coatings, produced by DC reactive magnetron sputtering, has been studied and reported as a function of electrode potential (-0.9 V, -0.5 V, 0.0 V and +0.5 V) and applied load (3, 6 and 9 N). The study was conducted in a reciprocating sliding tribosystem (Plint TE 67/E) in a bio fluid (an artificial perspiration solution) at room temperature. During the wear tests, both the open-circuit potential and the corrosion current were monitored. The results showed that electrode potential and load have a significant influence on the total material loss. The variations in Rp (polarization resistance) and Cf(capacitance) before and after sliding, obtained by Electrochemical Impedance Spectroscopy (EIS) were evaluated in order to provide an understanding of the resistance of the film in such conditions. Tribo-corrosion maps were generated, based on the results, indicating the change in mechanisms of the tribological and corrosion parameters for such coatings

Optimal Inverter-Based Resource Installation to Minimize Technical Energy Losses in Distribution Systems

This paper proposes an algorithm for the optimal installation of inverter-based resources (IBR) composed of wind energy conversion systems, photovoltaic systems, and battery energy storage systems in distribution systems using genetic algorithm (GA) and the cuckoo search (CS) as optimization techniques. The OpenDSS software is used to calculate the power flow in the distribution system with different penetration levels of IBRs. It is used a standard load shape of the IEEE 123 bus system programmed in OpenDSS and irradiance, temperature, and wind speed curves from Brazil. The proposed algorithm, using a genetic algorithm and cuckoo search, was able to define the quantity and the location of hybrid renewable generation arrangements reducing electrical energy losses. Case studies were carried out for maximum penetration from 20% to 60%, totaling 5 cases, where each simulation was performed for a period of 24 hours. It is simple, fast and efficient, achieving satisfactory results and being able to be applied to larger systems. The proposed method stands out for the possibility of using IBR in conjunction with energy storage, in addition to having a customizable hybrid array and being able to carry out case studies with high penetration while optimally locating and sizing the hybrid array configured accordingly with the needs of each problem, reducing losses and maintaining the quality of the system\u27s electrical voltage

Mass-luminosity relation for FGK main sequence stars: metallicity and age contributions

The stellar mass-luminosity relation (MLR) is one of the most famous empirical "laws", discovered in the beginning of the 20th century. MLR is still used to estimate stellar masses for nearby stars, particularly for those that are not binary systems, hence the mass cannot be derived directly from the observations. It's well known that the MLR has a statistical dispersion which cannot be explained exclusively due to the observational errors in luminosity (or mass). It is an intrinsic dispersion caused by the differences in age and chemical composition from star to star. In this work we discuss the impact of age and metallicity on the MLR. Using the recent data on mass, luminosity, metallicity, and age for 26 FGK stars (all members of binary systems, with observational mass-errors <= 3%), including the Sun, we derive the MLR taking into account, separately, mass-luminosity, mass-luminosity-metallicity, and mass-luminosity-metallicity-age. Our results show that the inclusion of age and metallicity in the MLR, for FGK stars, improves the individual mass estimation by 5% to 15%.Comment: 7 pages, 4 figures, 1 table, accepted in Astrophysics and Space Scienc

Poor disability outcomes in the management of Low Back Pain patients in Portugal

Trabalho apresentado em 10th Interdisciplinary World Congress on Low Back & Pelvic Girdle Pain, 28-31 de outubro 2019, Antuérpia, BélgicaN/

Percepção de professores sobre epilepsia

PURPOSE: To identify in a town of Brazil the knowledge, attitude and perception of epilepsy in teachers of elementary schools and to compare these before and after a training exercise. METHODS: Teachers of nine public schools of Barão Geraldo, Campinas, Brazil completed a questionnaire. Two researchers had meetings with teachers, presenting the Global Campaign Epilepsy out of the shadows, when the questionnaire was first completed by all attendees. Twenty teachers of these schools were motivated to attend a training course entitled Epilepsy and Health as part of their continuous education programme. Two years later the same questionnaire was again completed (post-test) by these 20 teachers. RESULTS: 100 teachers originally completed the questionnaire (97 women, mean age 42 years, 64 married). Forty-three percent of teachers said that they had enough knowledge regarding epilepsy and 20% said that they had poor knowledge about the condition. Regarding the IQ of children with epilepsy, 45% of teachers believed that they had average IQ, 18% above average, six percent under average and 29% did not know. Teachers believed that children with epilepsy have a higher possibility of acquiring mental disease in the future (51%); that epilepsy is a disease (68%); that epilepsy is contagious (1%); epilepsy is treatable (90%). After the course, the teachers beliefs seem to have improved. DISCUSSION: This work with elementary school teachers identified difficulties related to epilepsy which, if addressed, may help promote better quality of life of people with epilepsy in the community and help to decrease stigma attached to the condition. Better informed teachers are likely to have a more positive attitude and this will be passed to others. Educational campaigns about epilepsy amongst teachers should be encouraged as this may improve the management of epilepsy, by helping to develop a well informed and tolerant community.OBJETIVO: Identificar atitudes e percepção dos professores do ensino fundamental a respeito da epilepsia, antes e depois de um curso específico sobre o tema. MÉTODO: Participaram da pesquisa professores de nove escolas da rede pública do ensino fundamental de Barão Geraldo, distrito de Campinas, SP. Dois pesquisadores reuniram-se com os professores e apresentaram a Campanha Global Epilepsia fora das sombras, momento também em que os questionários foram aplicados. Vinte professores ficaram motivados para fazer o curso de extensão Temas transversais: epilepsia e saúde. Após este curso, os questionários foram re-aplicados. RESULTADOS: Foram aplicados 100 questionários em professores das nove escolas, sendo que: noventa e sete professores eram do sexo feminino, idade média de 42 (D.P. 22 a 63) e 64 estavam casados. Quarenta e três professores declararam possuir conhecimento sobre epilepsia abaixo da média e 20, disseram possuir um pobre conhecimento sobre a condição. No que diz respeito à idéias sobre epilepsia, os professores acham que: as crianças com epilepsia tem QI igual (45%), na média (18%), abaixo da média (6%) e não sabem opinar (29%); crianças com epilepsia têm maior chance de terem doença mental no futuro (51%); a epilepsia é uma doença (68%); a epilepsia é contagiosa (1%); a epilepsia é tratável (90%). Após o curso, crenças e mitos sobre epilepsia dos professores mostraram diferenças significativas. DISCUSSÃO: Idéias errôneas sobre epilepsia podem ser mudadas através de cursos educacionais sobre epilepsia. Este trabalho, realizado com professores do ensino fundamental, visou a identificação das dificuldades relacionadas à epilepsia para promover a redução do estigma. É importante que professores sejam melhor instruídos sobre a epilepsia para consequentemente, ter atitudes mais positivas em relação às crianças com epilepsia. Acreditamos que professores mais capacitados melhoram a maneira de lidar e de se relacionar com crianças com epilepsia, para a construção de uma comunidade bem informada e mais tolerante para lidar com as diferenças.283

Biofertilizante agrobio: Uma alternativa no controle da mancha bacteriana em mudas de pimentão (Capsicum annuum l.)

Agrobio é um biofertilizante líquido fabricado à base de esterco bovino, água, melaço e sais minerais, que são submetidos a um processo de fermentação à temperatura ambiente por 56 dias em recipientes abertos. Este produto tem sido largamente utilizado com sucesso por agricultores orgânicos e convencionais em todo o estado do Rio de Janeiro, no controle de várias enfermidades vegetais em diferentes culturas. Em bioensaios realizados em casa de vegetação, observou-se uma ação bacteriostática equivalente a de produtos químicos comerciais contra Xanthomonas campestris pv. vesicatoria em mudas de pimentão (Capsicum annuum L.), numa concentração de 5%. Nos bioensaios in vitro, onde foram testadas as concentrações de 2, 5 10 e 50% do Agrobio comercial, observouse que, a partir da concentração de 5%, ocorreu um nível satisfatório de inibição do crescimento bacteriano, apesar deste ter sido inferior ao obtido com o uso de sulfato de cobre e sulfato de estreptomicina

Stellar populations of classical and pseudo-bulges for a sample of isolated spiral galaxies

In this paper we present the stellar population synthesis results for a sample of 75 bulges in isolated spiral Sb-Sc galaxies, using the spectroscopic data from the Sloan Digital Sky Survey and the STARLIGHT code. We find that both pseudo-bulges and classical bulges in our sample are predominantly composed of old stellar populations, with mean mass-weighted stellar age around 10 Gyr. While the stellar population of pseudo-bulges is, in general, younger than that of classical bulges, the difference is not significant, which indicates that it is hard to distinguish pseudo-bulges from classical bulges, at least for these isolated galaxies, only based on their stellar populations. Pseudo-bulges have star formation activities with relatively longer timescale than classical bulges, indicating that secular evolution is more important in this kind of systems. Our results also show that pseudo-bulges have a lower stellar velocity dispersion than their classical counterparts, which suggests that classical bulges are more dispersion-supported than pseudo-bulges.Comment: 10 pages, 8 figures. Accepted for publication in Astrophysics & Space Scienc

Theoretical description of phase coexistence in model C60

We have investigated the phase diagram of the Girifalco model of C60 fullerene in the framework provided by the MHNC and the SCOZA liquid state theories, and by a Perturbation Theory (PT), for the free energy of the solid phase. We present an extended assessment of such theories as set against a recent Monte Carlo study of the same model [D. Costa et al, J. Chem. Phys. 118:304 (2003)]. We have compared the theoretical predictions with the corresponding simulation results for several thermodynamic properties. Then we have determined the phase diagram of the model, by using either the SCOZA, or the MHNC, or the PT predictions for one of the coexisting phases, and the simulation data for the other phase, in order to separately ascertain the accuracy of each theory. It turns out that the overall appearance of the phase portrait is reproduced fairly well by all theories, with remarkable accuracy as for the melting line and the solid-vapor equilibrium. The MHNC and SCOZA results for the liquid-vapor coexistence, as well as for the corresponding critical points, are quite accurate. All results are discussed in terms of the basic assumptions underlying each theory. We have selected the MHNC for the fluid and the first-order PT for the solid phase, as the most accurate tools to investigate the phase behavior of the model in terms of purely theoretical approaches. The overall results appear as a robust benchmark for further theoretical investigations on higher order C(n>60) fullerenes, as well as on other fullerene-related materials, whose description can be based on a modelization similar to that adopted in this work.Comment: RevTeX4, 15 pages, 7 figures; submitted to Phys. Rev.

A tetragonal-to-monoclinic phase transition in a ferroelectric perovskite: the structure of PbZr(0.52)Ti(0.48)O3

The perovskite-like ferroelectric system PbZr(1-x)Ti(x)O3 (PZT) has a nearly vertical morphotropic phase boundary (MPB) around x=0.45-0.50. Recent synchrotron x-ray powder diffraction measurements by Noheda et al. [Appl. Phys. Lett. 74, 2059 (1999)] have revealed a new monoclinic phase between the previously-established tetragonal and rhombohedral regions. In the present work we describe a Rietveld analysis of the detailed structure of the tetragonal and monoclinic PZT phases on a sample with x= 0.48 for which the lattice parameters are respectively: at= 4.044 A, ct= 4.138 A, at 325 K, and am= 5.721 A, bm= 5.708 A, cm= 4.138 A, beta= 90.496 deg., at 20K. In the tetragonal phase the shifts of the atoms along the polar [001] direction are similar to those in PbTiO3 but the refinement indicates that there are, in addition, local disordered shifts of the Pb atoms of ~0.2 A perpendicular to the polar axis.. The monoclinic structure can be viewed as a condensation along one of the directions of the local displacements present in the tetragonal phase. It equally well corresponds to a freezing-out of the local displacements along one of the directions recently reported by Corker et al.[J. Phys. Condens. Matter 10, 6251 (1998)] for rhombohedral PZT. The monoclinic structure therefore provides a microscopic picture of the MPB region in which one of the "locally" monoclinic phases in the "average" rhombohedral or tetragonal structures freezes out, and thus represents a bridge between these two phases.Comment: REVTeX, 7 figures. Modifications after referee's suggestion: new figure (figure 5), comments in 2nd para. (Sect.III) and in 2nd & 3rd para. (Sect. IV-a), in the abstract: "...of ~0.2 A perpendicular to the polar axis.