Sugar markers in aerosol particles from an agro-industrial region in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Studying Close Approaches for a Cloud of Particles Considering Atmospheric Drag

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dynamics of Space Particles and Spacecrafts Passing by the Atmosphere of the Earth

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cyclodextrin Inclusion Complexes Loaded in Particles as Drug Carrier Systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efficacy of Surface Treatments on the Bond Strength of Resin Cements to Two Brands of Zirconia Ceramic

Purpose: To compare the shear bond strength (SBS) of two cements to two Y-TZP ceramics subjected to different surface treatments.Materials and Methods: Zirconia specimens were made from Lava (n = 36) and IPS e.max ZirCAD (n = 36), and their surfaces were treated as follows: no treatment (control), silica coating with 30-mu m silica-modified alumina (Al2O3) particles (CoJet Sand), or coating with liners Lava Ceram for Lava and Intensive ZirLiner for IPS e.max ZirCAD. Composite resin cylinders were bonded to zirconia with Panavia F or RelyX Unicem resin cements. All specimens were thermocycled (6000 cycles at 5 degrees C/55 degrees C) and subjected to SBS testing. Data were analyzed by post-hoc test Tamhane T2 and Scheffe tests (alpha = 0.05). Failure mode was analyzed by stereomicroscope and SEM.Results: With both zirconia brands, CoJet Sand showed significantly higher SBS values than control groups only when used with RelyX Unicem (p = 0.0001). Surface treatment with liners gave higher SBS than control groups with both ceramic brands and cements (p < 0.001). With both zirconia brands, the highest SBS values were obtained with the CoJet and RelyX Unicem combination (> 13.47 MPa). Panavia F cement showed significantly better results when coupled with liner surface treatment rather than with CoJet (p = 0.0001, SBS > 12.23 MPa). In untreated controls, Panavia F showed higher bond strength than RelyX Unicem; the difference was significant (p = 0.016) in IPS e.max ZirCAD. The nontreated specimens and those treated with CoJet Sand exhibited a high percentage of adhesive and mixed A (primarily adhesive) failures, while the specimens treated with liners presented an increase in mixed A and mixed C (primarily cohesive) failures as well as some cohesive failure in the bulk of Lava Ceram for both cements.Conclusion: CoJet Sand and liner application effectively improved the SBS between zirconia and luting cements. This study suggests that different interactions between surface treatments and luting cements yield different SBS: in clinical practice, these interactions should be considered when combining luting cements with surface treatments in order to obtain the maximum bond strength to zirconia restorations.

Statistical properties for a dissipative model of relativistic particles in a wave packet: A parameter space investigation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Prediction of the combustion process in fluidized bed based on physical-chemical properties of biomass particles and their hydrodynamic behaviors

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização de superfície, adesiva e mecânica de uma zircônia parcialmente estabilizada por ítria em função da partícula ou do momento do jateamento

Pós-graduação em Reabilitação Oral - FOAR

Synthesis and characterization of alpha-nickel (II) hydroxide particles on organic-inorganic matrix and its application in a sensitive electrochemical sensor for vitamin D determination

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoluminescence in NaNbO3 particles and films

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Separation of particles leading either to decay or unlimited growth of energy in a driven stadium-like billiard

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hawking radiation from Elko particles tunnelling across black-strings horizon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização geológica do perfil laterítico no município de Rondon do Pará, bloco sul do projeto Alumina Rondon

This completion of course work has as its object of study the Bauxite Province of Paragominas regarded as the richest Amazon bauxite province and whose genesis is related to laterization processes responsible for the formation of mineral deposits of the Rondon Alumina Project, designed to assess areas in the southeast of Pará State, for mineral resources exploration of bauxite, which is the main source of aluminum in the country. Located in the region of Rondon do Pará - PA, the study area is geologically inserted in Lithostratigraphic Unit called Cobertura Laterítica Matura (Mature Lateritic Cover), formed by alteration of paleotropics Cretaceous siliciclastic rocks, and its geomorphology corresponds to a broad plateau with displays of representative profiles of the processes that acted in the region. In this context, the present research aims to characterize the geological evolution of the laterite profile, with detailed studies in the area, geological description of the formations from the bauxite surfaces, and mineralogical composition litochemical of different horizons that were correlated and deployed in an evolutionary model compatible with its traits. The data collected during the analysis subsidized metalogenetic understanding of the processes that acted in the enrichment of aluminum and iron as well as the redistribution of the latter modified profile. The results and information were embodied in the form of geological characterization of the different constituents of mineral associations of bauxite horizons, similarities or differences in both textural and structural aspects, in order to propose a evolutionary model with retaken of gibbsitization processes

Vitrocerâmicas porosas via conformação e consolidação com amidos

The search for new methods of manufacture of glass-ceramics with controlled porosity and permeability is interesting of the industrial and commercial point of view, and a challenge of great complexity. Porous glass-ceramics produced by sintering and crystallization of glasses can find applications, for example, as filters, materials with bactericidal properties, bio-implants, as catalytic and enzymes supports, among others. An alternative and low cost method of ceramic manufacture reaching different levels of porosity, for diverse purposes, is the conformation assisted by addition of starch, known as consolidation with starch. The objective of this project is to study the process of conformation with starch for making porous glass-ceramics from a commercial glass in the system Na2O-CaO-SiO2, whose kinetics of sintering by viscous flow and surface crystallization are known. The method of conformation with starches is innovative for glass-ceramics and its development opens the way for obtaining a new class of materials. We found a possible route for the production of porous compacts of glass particles, from the powder preparation to the removal of starch. It was observed that a glass powder obtained by dry milling in a ball mill with alumina balls for 24 h, afterwards mixed with water in an eccentric ball mill for 2 h, without the addition of a deflocculant, and subsequently mixed with starch also in an eccentric ball mill for 5 min resulted in slurries stable against sedimentation