633 research outputs found

    Recycling of residual IGCC slags and their benefits as degreasers in ceramics

    Get PDF
    This work studies the evolution of IGCC slag grains within a ceramic matrix fired at different temperatures to investigate the effect of using IGCC slag as a degreaser. Pressed ceramic specimens from two clay mixtures are used in this study. The M1 mixture is composed of standard clays, whereas the M2 mixture is composed of the same clay mixture as M1 mixture but contains 15% by weight IGCC slag. The amount of IGCC slag added coincides with the amount of slag typically used as a degreaser in the ceramic industry. Specimens are fired at 950 ºC, 1000 ºC, 1050 ºC, 1100 ºC and 1150 ºC. The mineralogical composition and the IGCC slag grain shape within the ceramic matrix are determined by X-ray diffraction, polarized light microscopy and scanning electron microscopy. The results reveal that the surface of the slag grains is welded to the ceramic matrix while the quartz grains are separated, which causes increased water absorption and reduces the mechanical strength. IGCC slag, however, reduces water absorption. This behaviour is due to the softening temperature of the slag. This property is quite important from an industrial viewpoint because IGCC slag can serve as an alternative to traditional degreasing agents in the ceramic building industry. Additionally, using IGCC slag allows for the transformation of waste into a secondary raw material, thereby avoiding disposal at landfills; moreover, these industrial wastes are made inert and improve the properties of ceramics

    Class, type and position of 9148 surgically removed third molars in 3206 patients : a retrospective study

    Get PDF
    Objective: To investigate the class, type, position, diagnosis and most common procedures used in the surgical removal of third molars, and evaluate the sex and age distribution in a representative sample of Mexican patients. Study Design: A retrospective descriptive study was made covering the period 1993-2008 in relation to 9148 extracted third molars in 3206 patients treated in the Dental School of Salle Bajío University, A.C. (Mexico). Patients of either sex and aged 11-59 years, with at least one third molar programmed for surgical removal, were included in the study. A descriptive statistical study was made. Results: The mean patient age was 27.6 ± 10.6 years. There were 2093 females (65.3%) and 1111 males (34.6%). In relation to the 4025 upper molars, extraction was decided for prophylactic reasons in 3827 cases (95.08%). Type A presentations were recorded in 1929 cases (47.9%), with a vertical position in 1931 teeth (48%). In relation to the 5123 lower third molars, extraction was likewise most often indicated for prophylactic reasons (4424 cases, 86.36%). A total of 2353 teeth corresponded to type A (45.9%), 2545 were class I cases (49.7%), and a mesioangular position was observed in 1850 cases (36.1%). Conclusions: The present study shows that in Mexican patients, upper third molars most often correspond to type A and class I, with a vertical position, while lower third molars predominantly correspond to type A and class I, with a mesioangular position. This information can help dental surgeons take better decisions before and after surgery, to the benefit of their patients

    Factores asociados a la no realización de examen citopatológico en São Leopoldo, Rio Grande do Sul, Brasil, 2015: estudio transversal de base poblacional

    Get PDF
    Objetivo: estimar a prevalência de exame citopatológico não realizado nos últimos três anos e de nunca realizado em mulheres, e analisar fatores associados. Métodos: estudo transversal, com mulheres de 20 a 69 anos de idade, em São Leopoldo, RS, Brasil, em 2015; calcularam-se as razões de prevalência (RP) por regressão de Poisson. Resultados: entre 919 mulheres, a prevalência de exame atrasado foi 17,8% (intervalo de confiança de 95% [IC95%15,4;20,3), e de nunca realizado, 8,1% (IC95%6,3;9,8); na análise ajustada, o aumento na prevalência de exame atrasado mostrou-se associado à classe econômica D/E (RP=2,1 - IC95%1,3;3,5), idade de 20-29 anos (RP=3,2 - IC95%2,1;4,9) e nenhuma consulta realizada (RP=3,0 - IC95%2,1;4,1); nunca ter realizado exame associou-se com classe econômica D/E (RP=2,6 - IC95%1,4;5,0), idade de 20-29 anos (RP=24,1 - IC95%6,4;90,9) e nenhuma consulta (RP=2,9 - IC95%1,7;4,8). Conclusão: a cobertura de exame foi alta e com iniquidade.Objective: to estimate the prevalence of Pap tests not performed in the last three years and never performed in women and to analyze associated factors. Methods: this was a cross-sectional study with women aged 20 to 69 years living in São Leopoldo, RS, Brazil, in 2015; prevalence ratios (PR) were calculated using Poisson regression. Results: among 919 women, prevalence of delayed testing was 17.8% (95% confidence interval [95%CI]15.4;20.3) and never tested prevalence was 8.1% (95%CI6.3%;9.8%); in the adjusted analysis, the increase in the prevalence of delayed testing was associated with economic class D/E (PR=2.1 – 95%CI1.3;3.5), being aged 20-29 years (PR=3.2 – 95%CI2.1;4.9) and not having had a medical appointment (PR=3.0 – 95%CI2.1;4.1); never having tested was associated with economic class D/E (PR=2.6 – 95%CI1.4;5.0), being aged 20-29 years (PR=24.1 – 95%CI6.4;90.9), and not having had a medical appointment (PR=2.9 – 95%CI1.7;4.8). Conclusion: coverage of the test was high but characterized by social inequality.Objetivo: estimar la prevalencia de examen en mujeres, no realizado en los últimos tres años y de nunca realizado, y analizar factores asociados. Métodos: estudio transversal con mujeres de 20 a 69 años de edad de São Leopoldo, RS, Brasil, en 2015; se calcularon las razones de prevalencia (RP) por la regresión de Poisson. Resultados: entre 919 mujeres, la prevalencia de examen retrasado fue 17,8% (intervalo de confianza del 95% [IC95%]15,4;20,3) y de nunca realizado fue del 8,1% (IC95%6,3;9,8); en el análisis ajustado, el aumento en la prevalencia de examen retrasado se asoció con clase económica D/E (RP=2,1 – IC95%1,3;3,5), a edad entre 20-29 años (RP=3,2 – IC95%2,1;4,9) y ninguna consulta (RP=3,0 – IC95%2,1;4,1); nunca haber realizado examen se asoció con clase D/E (RP=2,6 – IC95%1,4;5,0), a 20- 29 años de edad (RP=24,1 – IC95%6,4;90,9) y ninguna consulta (RP=2,9 – IC95%1,7;4,8). Conclusión: la cobertura de examen fue alta y con inequidad

    Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA

    Get PDF
    Correlations between charged particles in deep inelastic ep scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C

    Measurement of inclusive D*+- and associated dijet cross sections in photoproduction at HERA

    Get PDF
    Inclusive photoproduction of D*+- mesons has been measured for photon-proton centre-of-mass energies in the range 130 < W < 280 GeV and a photon virtuality Q^2 < 1 GeV^2. The data sample used corresponds to an integrated luminosity of 37 pb^-1. Total and differential cross sections as functions of the D* transverse momentum and pseudorapidity are presented in restricted kinematical regions and the data are compared with next-to-leading order (NLO) perturbative QCD calculations using the "massive charm" and "massless charm" schemes. The measured cross sections are generally above the NLO calculations, in particular in the forward (proton) direction. The large data sample also allows the study of dijet production associated with charm. A significant resolved as well as a direct photon component contribute to the cross section. Leading order QCD Monte Carlo calculations indicate that the resolved contribution arises from a significant charm component in the photon. A massive charm NLO parton level calculation yields lower cross sections compared to the measured results in a kinematic region where the resolved photon contribution is significant.Comment: 32 pages including 6 figure

    D* Production in Deep Inelastic Scattering at HERA

    Get PDF
    This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel D+(D0Kπ+)π+D^{*+}\to (D^0 \to K^- \pi^+) \pi^+ (+ c.c.) has been used in the study. The e+pe^+p cross section for inclusive D^{*\pm} production with 5<Q2<100GeV25<Q^2<100 GeV^2 and y<0.7y<0.7 is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {1.3<pT(D±)<9.01.3<p_T(D^{*\pm})<9.0 GeV and η(D±)<1.5| \eta(D^{*\pm}) |<1.5}. Differential cross sections as functions of p_T(D^{*\pm}), η(D±),W\eta(D^{*\pm}), W and Q2Q^2 are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and η\eta(D^{*\pm}), the charm contribution F2ccˉ(x,Q2)F_2^{c\bar{c}}(x,Q^2) to the proton structure function is determined for Bjorken xx between 2 \cdot 104^{-4} and 5 \cdot 103^{-3}.Comment: 17 pages including 4 figure

    Plastisol Foaming Process. Decomposition of the Foaming Agent, Polymer Behavior in the Corresponding Temperature Range and Resulting Foam Properties

    Get PDF
    The decomposition of azodicarbonamide, used as foaming agent in PVC - plasticizer (1/1) plastisols was studied by DSC. Nineteen different plasticizers, all belonging to the ester family, two being polymeric (polyadipates), were compared. The temperature of maximum decomposition rate (in anisothermal regime at 5 K min-1 scanning rate), ranges between 434 and 452 K. The heat of decomposition ranges between 8.7 and 12.5 J g -1. Some trends of variation of these parameters appear significant and are discussed in terms of solvent (matrix) and viscosity effects on the decomposition reactions. The shear modulus at 1 Hz frequency was determined at the temperature of maximum rate of foaming agent decomposition, and differs significantly from a sample to another. The foam density was determined at ambient temperature and the volume fraction of bubbles was used as criterion to judge the efficiency of the foaming process. The results reveal the existence of an optimal shear modulus of the order of 2 kPa that corresponds roughly to plasticizer molar masses of the order of 450 ± 50 g mol-1. Heavier plasticizers, especially polymeric ones are too difficult to deform. Lighter plasticizers such as diethyl phthalate (DEP) deform too easily and presumably facilitate bubble collapse

    Observation of Scaling Violations in Scaled Momentum Distributions at HERA

    Get PDF
    Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of xx and Q2Q^2 using the ZEUS detector. The evolution of the scaled momentum, xpx_p, with Q2,Q^2, in the range 10 to 1280 GeV2GeV^2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2Q^2.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

    Data standardization of plant-pollinator interactions

    Get PDF
    Background: Animal pollination is an important ecosystem function and service, ensuring both the integrity of natural systems and human well-being. Although many knowledge shortfalls remain, some high-quality data sets on biological interactions are now available. The development and adoption of standards for biodiversity data and metadata has promoted great advances in biological data sharing and aggregation, supporting large-scale studies and science-based public policies. However, these standards are currently not suitable to fully support interaction data sharing. Results: Here we present a vocabulary of terms and a data model for sharing plant–pollinator interactions data based on the Darwin Core standard. The vocabulary introduces 48 new terms targeting several aspects of plant–pollinator interactions and can be used to capture information from different approaches and scales. Additionally, we provide solutions for data serialization using RDF, XML, and DwC-Archives and recommendations of existing controlled vocabularies for some of the terms. Our contribution supports open access to standardized data on plant–pollinator interactions. Conclusions: The adoption of the vocabulary would facilitate data sharing to support studies ranging from the spatial and temporal distribution of interactions to the taxonomic, phenological, functional, and phylogenetic aspects of plant–pollinator interactions. We expect to fill data and knowledge gaps, thus further enabling scientific research on the ecology and evolution of plant–pollinator communities, biodiversity conservation, ecosystem services, and the development of public policies. The proposed data model is flexible and can be adapted for sharing other types of interactions data by developing discipline-specific vocabularies of terms.Fil: Salim, José A. Universidade de Sao Paulo; BrasilFil: Saraiva, Antonio M.. Universidade de Sao Paulo; BrasilFil: Zermoglio, Paula Florencia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Norte. Instituto de Investigaciones En Recursos Naturales, Agroecologia y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones En Recursos Naturales, Agroecologia y Desarrollo Rural.; ArgentinaFil: Agostini, Kayna. Universidade Federal do São Carlos; BrasilFil: Wolowski, Marina. Universidade Federal de Alfenas; BrasilFil: Drucker, Debora P.. Empresa Brasileira de Pesquisa Agropecuaria (embrapa);Fil: Soares, Filipi M.. Universidade de Sao Paulo; BrasilFil: Bergamo, Pedro J.. Jardim Botânico do Rio de Janeiro; BrasilFil: Varassin, Isabela G.. Universidade Federal do Paraná; BrasilFil: Freitas, Leandro. Jardim Botânico do Rio de Janeiro; BrasilFil: Maués, Márcia M.. Empresa Brasileira de Pesquisa Agropecuaria (embrapa);Fil: Rech, Andre R.. Universidade Federal dos Vales do Jequitinhonha e Mucuri; BrasilFil: Veiga, Allan K.. Universidade de Sao Paulo; BrasilFil: Acosta, Andre L.. Instituto Tecnológico Vale; BrasilFil: Araujo, Andréa C. Universidade Federal do Mato Grosso do Sul; BrasilFil: Nogueira, Anselmo. Universidad Federal do Abc; BrasilFil: Blochtein, Betina. Pontificia Universidade Católica do Rio Grande do Sul; BrasilFil: Freitas, Breno M.. Universidade Estadual do Ceará; BrasilFil: Albertini, Bruno C.. Universidade de Sao Paulo; BrasilFil: Maia Silva, Camila. Universidade Federal Rural Do Semi Arido; BrasilFil: Nunes, Carlos E. P.. University of Stirling; BrasilFil: Pires, Carmen S. S.. Empresa Brasileira de Pesquisa Agropecuaria (embrapa);Fil: Dos Santos, Charles F.. Pontificia Universidade Católica do Rio Grande do Sul; BrasilFil: Queiroz, Elisa P.. Universidade de Sao Paulo; BrasilFil: Cartolano, Etienne A.. Universidade de Sao Paulo; BrasilFil: de Oliveira, Favízia F. Universidade Federal da Bahia; BrasilFil: Amorim, Felipe W.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Fontúrbel, Francisco E.. Pontificia Universidad Católica de Valparaíso; ChileFil: da Silva, Gleycon V.. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Consolaro, Hélder. Universidade Federal de Catalão; Brasi
    corecore