1,423 research outputs found

    Modeling of the penultimate unit effect in chain growth copolymerizations

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    The present work addresses the modeling and simulation of the addition of copolymerizations of styrene and methyl methacrylate in batch mode, and the formation of tailored vinyl acetate/acrylic acid copolymers is evaluated through stochastic optimization procedures based on the Monte Carlo method. A kinetic model of the free-radical reaction was proposed in order to predict the behavior of the reaction system taking into consideration the presence of the penultimate unit effect. The profiles of conversion and copolymer composition were also evaluated considering the effect of the medium viscosity (kinetic phenomena related to gel and glass effects) on the reaction performance. It was shown that the proposed model for chain-growth copolymerization is able to describe strong nonlinear behaviors such as autoacceleration of the polymerization and drift of copolymer composition. It was also shown that copolymers with homogeneous composition can be successfully synthesized through manipulation of the monomer feed flow rate based on a stochastic optimization procedure

    Vector diseases treatment based on intermediate complexion using textile substrates

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    The most efficient insect repellents are DEET (N, N-diethhyl-meta-toluamide) from synthetic origin and citronella essential oil from natural origin. However, there are other products that can also be used as insect repellents from synthetic origin, such as: DEPA (N, N-Diethyl Phenylacetamide), Icaridin, IR3535 and Permethrin and, of natural origin: Carapa guianesis, Atemisia vulgaris, Ocimim., basilicum, Cinnamomum camphora, Corymbia citriodora, Eucalyptus sp, Cymbopogon, Mentha pulegium. All those products are the basis of most commercial repellents; however the action of these repellents is of short duration, due to the volatility of the chemical compounds of these products and, therefore they offer an uncontrolled release. The authors have shown that there would be an alternative to control their release based on the complexation of the active principle (the repellent oil). Thus, the repellent will have its prolonged effect and will protect the user longer. The active principle can be used in repellent products, applied to the skin via spray or can be used on textiles. According to Lis Arias et al. when used in textiles, these products become biofunctional, enabling the delivery of assets for cosmetotextiles applications. Due to its specific response, biofunctional textiles are especially useful when the textile comes into close contact with the skin. Thus, these products can be used as insect repellents, reducing the number of infections caused by these vectorsPostprint (published version

    Analyzing the Targets of Hate in Online Social Media

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    Social media systems allow Internet users a congenial platform to freely express their thoughts and opinions. Although this property represents incredible and unique communication opportunities, it also brings along important challenges. Online hate speech is an archetypal example of such challenges. Despite its magnitude and scale, there is a significant gap in understanding the nature of hate speech on social media. In this paper, we provide the first of a kind systematic large scale measurement study of the main targets of hate speech in online social media. To do that, we gather traces from two social media systems: Whisper and Twitter. We then develop and validate a methodology to identify hate speech on both these systems. Our results identify online hate speech forms and offer a broader understanding of the phenomenon, providing directions for prevention and detection approaches.Comment: Short paper, 4 pages, 4 table

    ESQUERDAS LATINO-AMERICANAS E GASTO SOCIAL: HÁ COERÊNCIA ENTRE PROPOSTAS E PRÁTICAS?

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    This paper analyses social spending of left and center-left governments recently elected in Latin American countries. It compares the expenditure on targeted social programs as well as on health and education trying to identify what the actions these so-called progressive administrations would be bringing to thesocial field with regards to old practices. It also stresses the relation between proposals presented by these progressive actors before they were in power and what the put in practice afterwards

    Analysis of the incursion of international law of catastrophes to the normative territory of armed conflicts: when catastrophe and war collide

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    This reflection will deal particularly with the convergences between catastrophes and armed conflicts, which united form a new level of emergency and must be studied in all its anarchic complexity. Accordingly, it seeks to understand the interference of the new International Law of Catastrophes in the classic International Humanitarian Law. This brand-new area of International Law, therefore, will form a new legal framework to be standardized in the future in order to accelerate the emergency response cycle accepted and shared worldwide by international humanitarian organizations as minimum parameters for procedures and response flows. Therefore, this investigation will focus on presenting firstly the incursion of the International Law of Catastrophes to the normative territory of armed conflicts, and then the related cross-cutting factors determining the formation of humanitarian catastrophes arising from armed conflicts, as well as the new modality of the catastrophe itself

    Twist Removal Of Healed Vs. Nonhealed Implants-a Mechanical And Histological Study In Mini Pigs

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The objective of this study was to evaluate the effect of removal torque (reverse torque) of titanium implants in peri-implant bone. Methods: The P1-M1 teeth were extracted bilaterally of 6 mini pigs (BR-1). Each animal received 6 titanium implants, three for each side of mandible. On the right side of mandible, 3 implants reminded 9 months (9M) under masticatory activity and on the left side, other 3 implants were placed and immediately removed (IR). All 36 implants were removed by removal torque, and the recorded values were statistically analyzed. Animals were euthanized right after the removal torque and recording. Each third (cervical, medium, and apical) of peri-implant bone was extracted and analyzed histological and immunohistochemically. Student's t test was used to determine statistical differences in the values between the 9M and IR samples. Data were presented as means with standard deviations. The level of significance was set at 5% (P < 0.05). Results: Removal torque was higher in 9M experimental situation than in IR. Histological characteristics of mature bone were presented in the 9M experimental condition, and immature bone characteristics were presented in the IR experimental condition. Removal torque caused small fractures and rounding in the bone grooving. Immunohistochemical analysis reinforced the histological results; Student's t test provided statistically significant differences to osteocalcin expression in 9M samples and no statistically significant differences expression to collagen I in both experimental conditions (P < 0.05). Conclusions: Removal torque caused microscopical fractures and smoothing in the peri-implant bone grooves, but it does not compromise the bone healing.2CAPESCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Information architecture analysis using business intelligence tools based on the information needs of executives

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    Devising an information architecture system that enables an organization to centralize information regarding its operational, managerial and strategic performance is one of the challenges currently facing information technology. The present study aimed to analyze an information architecture system developed using Business Intelligence (BI) technology. The analysis was performed based on a questionnaire enquiring as to whether the information needs of executives were met during the process. A theoretical framework was applied consisting of information architecture and BI technology, using a case study methodology. Results indicated that the transaction processing systems studied did not meet the information needs of company executives. Information architecture using data warehousing, online analytical processing (OLAP) tools and data mining may provide a more agile means of meeting these needs. However, some items must be included and others modified, in addition to improving the culture of information use by company executives
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