Adsorption of two pesticides on a clay surface: a theoretical study

The contamination of water resources with many organic xenobiotic compounds poses a challenge to environmental sciences and technologies [1]. Although in many cases these contaminants are present only in small concentrations, the large variety of such compounds (some of which are classified as priority pollutants) is a matter of concern. Adsorption, alone or as part of a more complex water or wastewater treatment process, has been seen as playing a very important role in the removal of many of these pollutants [2]. In this regard, the choice of adsorbent materials is crucial, which requires an understanding of the details involved in the adsorption of more or less complex organic molecules by a variety of surfaces of different types. In addition to laboratory studies, computational studies may be valuable in this study [3]. MCPA (2-methyl-4-chlorophenoxyacetic acid, a herbicide) and Clofibric acid (2-(4-chlorophenoxy)-2-methylpropanoic, the metabolite of a pharmaceutical, clofibrate, and also a herbicide) are two phenoxy acids that differ only slightly in their structures. However, a quite distinct behavior in adsorption phenomena on clay materials has been observed in past studies [4]. By relating those differences with the molecules' structural features through atomistic computational studies, some insight may be gained into the respective adsorption processes of this type of compounds. In the present work quantum chemical calculations at density functional theory level have been performed to study the adsorption of MCPA and Clofibric acid by a clay surface model. Since hydration plays an important role for the adsorption process of these species, solvent effects were considered by inclusion of water molecules explicitly into the quantum chemical calculations. The deprotonated negatively charged species were found to strongly interact with the surface and the distinct behavior of both species upon adsorption was compared with experimental evidences

Socio-sportive experience and informal education of children and young people: Contributions to the citizenship of new generations

This presentation addresses the importance of socio-sports experiences, understood as an informal process of education in the construction of participatory citizenship of socially vulnerable children and young people. The study took place within the community of practices of a neighborhood, in Lisbon-Portugal. In fact, socio-sportive intervention can be configured as a space-time promoter of a multidimensional and empowerment vision of sustainable development of urban communities. It was through an on-site ethnographic observation study of the children's and youth experience in four informal sports activities - street football, capoeira, hip hop dance and the social circus - socially mediated by local community projects, that it was possible to identify collaborative practice models of collective construction of an integrative approach of informal education and sustainable social development, such as proximity social mediation, peer mentoring, popular education and collaborative action research. Informal models of education based on human rights, social justice and personal and social development, based on an ecosystem vision paradigm of urban development, through the expression of the children and youth trajectories and voices of the various community agents who collaborated in the course of research. The techniques used were participant observation, semi-directive and biographical interviews for tracing life trajectories and youth identities, life stories and also open interviews with project leaders. The premisse was that through sports it is possible to lead children and youth to educational attainment. The results let us perceive that, because it presupposes a setting of personal goals and the tentative to achieve them it implies persistence and continued work. Transferring these skills to the scholar domain, showed that their development in this area entails greater effectiveness in studying, making predict success in the future. It also implies the development of social relationship and teamwork skills. Combining informal education and sports is a rigorous, methodical, and holistic process, that takes the individual as a whole and as a multifaceted and complex being. The development of these competencies through informal educational methodologies assertively contributes, as was possible to see throughout this study, to the social inclusion to be done in a more sustained and consistent way.info:eu-repo/semantics/acceptedVersio

A relativistic quark model for the Omega- electromagnetic form factors

We compute the Omega- electromagnetic form factors and the decuplet baryon magnetic moments using a quark model application of the Covariant Spectator Theory. Our predictions for the Omega- electromagnetic form factors can be tested in the future by lattice QCD simulations at the physical strange quark mass.Comment: 13 pages, 5 figure

Mechanical and wear behaviours of nano and microfilled polymeric composite: effect of filler fraction and size

The addition of ceramic reinforced material, SiC particles, to resin matrices, results in the improvement of the overall performance of the composite, allowing the application of these materials as tribo-materials in industries such as: automotive, aeronautical and medical. Particle-reinforced polymeric composites are widely used as biomaterials, for example as dental filler materials and bone cements. These reinforced composites have improved mechanical and tribological performance and have higher values of elastic modulus and hardness, and also reduce the shrinkage during the polymerisation compared with resin matrices. However, the effect of the filler level in mechanical and tribological behaviour is not quite understood. The aim of this work is to determine the influence of the particle volume fraction and particle size in the wear loss of the composites and their antagonists. Reciprocating wear tests were conducted using a glass sphere against resin polyester silica reinforced composite in a controlled medium, with an abrasive slurry or distilled water. For 6 μm average particle dimension, seven particles contents were studied ranging from 0% to 46% of filler volume fraction (FVF). Afterwards, filler volume fractions of 10% and 30% were selected; and, for these percentages, 7 and 4 average particle dimensions were tested and were evaluated regarding their wear behaviour, respectively. The reinforcement particle dimensions used ranged from 0.1 μm to 22 μm with the 10% filler fraction, and for 30% of filler content the range extended from 3 μm to 22 μm. The results allow us to conclude that in an abrasive slurry medium the composite abrasion resistance decreases with the increase of the particle volume fraction, in spite of the accompanying rise in hardness and elastic modulus. With constant FVF, and abrasive slurry, the composite wear resistance increases with increasing average particle dimension. In a distilled water medium and with several FVF values, the minimum wear was registered for a median particle content of 24%. In this medium and with constant FVF the highest wear resistance occurred for average reinforcement particles of 6 μm. The removal mechanisms involved in the wear process are discussed, taking into account the systematic SEM observations to evaluate the wear mechanisms

A parameter for quantitative analysis of plasticity induced crack closure

Numerical models have been successfully developed to predict plasticity induced crack closure (PICC). However, despite the large research effort a full understanding of the links between physical parameters, residual plastic wake and PICC has not been achieved yet. The plastic extension of material behind crack tip, Δyp, obtained by the integration of vertical plastic deformation perpendicularly to crack flank, is proposed here to quantify the residual plastic field. The values of Δyp and PICC were obtained numerically in a M(T) specimen using the finite element method. An excellent correlation was found between PICC and Δyp which indicates that this parameter controls the phenomenon, and can be used to quantify the effect of physical parameters. An empirical model was developed to predict PICC assuming that the residual plastic field is a set of vertical plastic wedges, that the linear superposition principle applies and that the influence of a particular wedge exponentially decreases with distance to crack tip. The model was applied successfully to predict PICC for different residual plastic fields which provided an additional validation of Δyp as the parameter controlling PICC

Necesidades formativas de los trabajadores sociales portugueses en tiempos de austeridad

Nos últimos anos, Portugal atravessou um período de austeridade. Porém, as políticas de bem-estar não conseguiram dar respostas e!cazes, com efeitos ao nível do aumento da pobreza e exclusão social. Os/As assistentes sociais, confrontados/as com novos e complexos problemas, manifestaram di!culdades em dinamizar soluções. Deste modo, propusemonos a compreender as necessidades de formação que estes/as pro!ssionais apresentavam no contexto de crise económica e social. Para tal, aplicou-se um inquérito por questionário on-line aos/às assistentes sociais portugueses/as, tendo-se obtido 896 respostas válidas. As suas necessidades formativas concentraram-se na supervisão, nos conteúdos funcionais e deontologia, na intervenção familiar, na intervenção em crise e na ação social, sem descurar o desejo de reforço das competências em áreas inovadoras, como as línguas e a gestão de projetos e organizações. Apresentaram como motivações o aperfeiçoamento, o conhecimento das práticas inovadoras e preocupações cientí!cas, revelando, assim, a urgência em darem respostas aos desa!os da austeridade, através da procura de capacitação para uma práxis crítica e refléxivainfo:eu-repo/semantics/publishedVersio

Introduction to sustainability as a transversal competence in higher education

Sustainability in higher education institutions is little discussed, but there is a large amount of literature that mentions its importance for the awareness of all those who frequent their spaces, whether they are teachers, employees, or students. The understanding, by the human being, of the complex nature of the environment and the perception of the interdependence of the environmental elements in space and time is crucial and, for this reason, the education in this area must be accessible to all and at all levels of education, not matter what subject area. Since 2019, in the Soft Skills Lab of a public university was created a curricular unit called - Introduction to Sustainability, with the aim that students and everyone involved with the environment in a higher education institution can be fully aware of what it means to develop sustainability actions, both in the environment and in the very contents of the various courses developed in the institution they are a part of. This exploratory study aims to disseminate this experience with the 1st cycle students and also with workshops made with the employees as a practice that can be replicate in other institutions. The evaluation was made through the process of pedagogical monitoring students make every semester and in the case of the employees through a evaluation survey. It was very motivating to see the commitment that both students and employees have started to show in their daily behavior and even the creative suggestions for their participation in this matter.info:eu-repo/semantics/acceptedVersio

Managing doctor-patient relationships and turnover intention in Chinese hospitals with commitment HRM: the moderating role of pragmatism

A deteriorating doctor-patient relationship (DPR) and an increasing turnover of doctors are two challenges faced by Chinese public hospitals. The literature suggests dat commitment human resource (HR) practices may translate into better DPR and lower turnover intention. Given dat pragmatism is an important cultural value in Chinese society, this study aims to understand the extent to which pragmatism may effect the relationships among commitment HRM, DPR, and turnover intentions of doctors in China. A moderated SEM analysis with 508 samples shows dat commitment HR practices are TEMPTEMPeffective in improving DPR for all doctors surveyed, but its TEMPTEMPeffect on turnover intention depends upon the pragmatism-level of the respondents. Specifically, pragmatism TEMPhas a significant moderation TEMPTEMPeffect in the paths established from commitment HR practices to DPR and turnover intention in such a way dat, in the low-pragmatism sample, commitment HR practices are associated with better DPR, while DPR is associated negatively with lower turnover intention.info:eu-repo/semantics/acceptedVersio

Mechanical and tribological characterization of four commercial braking formulation materials

Organic friction materials for brake linings, namely brake pads are polymer matrix composites usually containing numerous macroscopic as well as microscopic constituents such as filamentary reinforcements, solid lubricants, abrasives and fillers. Their main objective of the these composite system are that a constant and stable coefficient of friction (COF) is provided irrespective of environmental conditions such as pressure, sliding velocity, temperature, humidity etc. Brake pads performance should be maintained over a wide range of stress conditions. Although the wear of the brake pad is inevitable, it should be minimized as far as possible. While cast iron has been the dominant material for brake discs, brake pad materials are constantly evolving into more complex composites. The main objectives of the present work is to characterize the physical and the tribological behavior of four commercial braking pads material formulations. For all compositions the studied factors are normal pressure and sliding speed, considering one braking-test protocol designed with temperature and friction load data acquisition. A double pad-on-disc tribological test configuration was used to determine tribological properties of brake pad for heavy vehicles commercial. Three wear tests via increased severity of rubbing conditions for a constant braking distance.The authors acknowledge Auto Travões Viseu-recondicionamento de Travões e embraiagens Lda the support through the provision of the frictrion linning materials presented in the study

How to measure banking regulation and supervision

This paper uses data from 141 countries to identify the variables that best characterize worldwide banking regulation and supervision practices. We apply a nonlinear principal components analysis with optimal variable transformation to deal with the variables’ mixed measurement levels and reduce data dimensionality. The robustness of the results is tested for different subsamples. The findings indicate that deposit insurance, liquidity, diversification requirements, complementary banking activities, and market discipline are the most reliable indicators to measure regulation. In contrast, resolution activities, the mandate of the head of the supervisory agency, and the report of prudential regulation infractions assume the same role for banking supervision. Capital requirements and ownership are of minor relevance and are sensitive to a country’s development level. China and Germany display the most distinct regulation practices, while China and the UK adopt the most stringent policies regarding supervision.info:eu-repo/semantics/publishedVersio