Tropical soils with high aluminum concentrations cause oxidative stress in two tomato genotypes

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

Mechanical and microstructural characterization of laser-welded joints of 6013-T4 aluminum alloy

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

Characterization of calcium phosphate coating produced by biomimetic method

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

Heterojunction between Al2O3 and SnO2 thin films for application in transparent FET

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hydroxyapatite coating deposited on grade 4 titanium by plasma electrolytic oxidation

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

Corrosion resistance of 2024 aluminum alloy coated with plasma deposited a-C:H:Si:O films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Abutment coating with diamond-like-carbon films to reduce implant-abutment bacterial leakage

Backgroud: The influence of diamond-like-carbon (DLC) films on bacterial leakage through the interface between abutments and dental implants of external hexagon (EH) and internal hexagon (IH) was evaluated. Film deposition was performed by PECVD (Plasma Enhanced Chemical Vapor Deposition). Sets of implants and abutments (N=180, n=30) were divided according to the connection design and the treatment of the abutment base: (1) no treatment (control); (2) DLC film deposition, and (3) Ag-DLC film deposition. Under sterile conditions, 1 µL of Enterococcus faecalis was inoculated inside the implants, and abutments were tightened. The sets were tested for immediate external contamination, suspended in test tubes containing sterile culture broth, and followed-up for five days. Turbidity of the broth indicated bacterial leakage. At the end of the period, the abutments were removed and the internal content of the implants was collected with paper points and plated in Petri dishes. They were incubated for 24 h for bacterial viability assessment and colony-forming unit (CFU) counting. Bacterial leakage was analyzed by Chi-square and Fisher exact tests (α=5%). The percentage of bacterial leakage was 16.09% for EH implants and 80.71% for IH implants (P<0.0001). The bacterial load was higher inside these implants (P=0.000). The type of implant significantly influenced the results (P=0.000), whereas the films did not (P=0.487). We concluded that: (1) IH implants showed a higher frequency of bacterial leakage and (2) the DLC and Ag-DLC films did not significantly reduce the frequency of bacterial leakage and bacteria load inside the implants.

Utilização de lama vermelha para oxidação eletrolítica assistida por plasma de liga de alumínio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Grinding of AISI 4340 steel with interrupted cutting by aluminum oxide grinding wheel

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

Comparison of the Fuel Needed to Transport Plastic Recyclables Verses Aluminum Recyclables from Yellowstone National Park

Research has provided no definitive answers on whether PET plastic bottles or aluminum cans are a more environmentally sustainable choice as soda containers. This paper researches the fuel used in recycling each of these materials from Yellowstone National Park to processing locations. The data is used to determine which of these alternatives use less fuel in this process. It was found that plastics use more fuel when transported from Yellowstone National Park to the processing center. Aluminum uses less fuel per ton to transport from Yellowstone to the processing center. The conclusions from this research may have implications on which material would be advised to use in selling soda in Yellowstone National Park.

Methodology of CO2 emission evaluation in the life cycle of office building facades

The construction industry is one of the greatest sources of pollution because of the high level of energy consumption during its life cycle. In addition to using energy while constructing a building, several systems also use power while the building is operating, especially the air-conditioning system. Energy consumption for this system is related, among other issues, to external air temperature and the required internal temperature of the building. The facades are elements which present the highest level of ambient heat transfer from the outside to the inside of tall buildings. Thus, the type of facade has an influence on energy consumption during the building life cycle and, consequently, contributes to buildings' CO2 emissions, because these emissions are directly connected to energy consumption. Therefore, the aim is to help develop a methodology for evaluating CO2 emissions generated during the life cycle of office building facades. The results, based on the parameters used in this study, show that facades using structural glazing and uncolored glass emit the most CO2 throughout their life cycle, followed by brick facades covered with compound aluminum panels or ACM (Aluminum Composite Material), facades using structural glazing and reflective glass and brick facades with plaster coating. On the other hand, the typology of facade that emits less CO2 is brickwork and mortar because its thermal barrier is better than structural glazing facade and materials used to produce this facade are better than brickwork and ACM. Finally, an uncertainty analysis was conducted to verify the accuracy of the results attained. (C) 2011 Elsevier Inc. All rights reserved.

Thallium Bromide Deposited Using Spray Coating

Spray coating was used to produce thallium bromide samples on glass substrates. The influence of several fabrication parameters on the final structural properties of the samples was investigated. Substrate position, substrate temperature, solution concentration, carrying gas, and solution flow were varied systematically, the physical deposition mechanism involved in each case being discussed. Total deposition time of about 3.5 h can lead to 62-mu m-thick films, comprising completely packed micrometer-sized crystalline grains. X-ray diffraction and scanning electron microscopy were used to characterize the samples. On the basis of the experimental data, the optimum fabrication conditions were identified. The technique offers an alternative method for fast, cheap fabrication of large-area devices for the detection of high-energy radiation, i.e., X-rays and gamma-rays, in medical imaging.

Preload Evaluation of Different Screws in External Hexagon Joint

Purpose: This study compared the maintenance of tightening torque in different retention screw types of implant-supported crowns. Materials and Methods: Twelve metallic crowns in UCLA abutments cast with cobalt-chromium alloy were attached to external hexagon osseointegrated implants with different retention screws: group A: titanium alloy retention screw; group B: gold alloy retention screw with gold coating; group C: titanium alloy retention screw with diamond-like carbon film coating; and group D: titanium alloy retention screw with aluminum titanium nitride coating. Three detorque measurements were obtained after torque insertion in each replica. Data were evaluated by analysis of variance (ANOVA), Tukey's test (P < 0.05), and t test (P < 0.05). Results: Detorque value reduced in all groups (P < 0.05). Group A retained the highest percentage of torque in comparison with the other groups (P < 0.05). Groups B and D retained the lowest percentage of torque without statistically significant difference between them (P < 0.05). Conclusions: All screw types exhibited reduction in the detorque value. The titanium screw maintained the highest percentage of torque whereas the gold-coated screw and the titanium screw with aluminum titanium nitride coating retained the lowest percentage. (Implant Dent 2012;21:46-50)

Quantum Monte Carlo study of small aluminum clusters Al-n (n=2-13)

Using fixed node diffusion quantum Monte Carlo (FN-DMC) simulations and density functional theory (DFT) within the generalized gradient approximations, we calculate the total energies of the relaxed and unrelaxed neutral, cationic, and anionic aluminum clusters, Al-n (n = 1-13). From the obtained total energies, we extract the ionization potential and electron detachment energy and compare with previous theoretical and experimental results. Our results for the electronic properties from both the FN-DMC and DFT calculations are in reasonably good agreement with the available experimental data. A comparison between the FN-DMC and DFT results reveals that their differences are a few tenths of electron volt for both the ionization potential and the electron detachment energy. We also observe two distinct behaviors in the electron correlation contribution to the total energies from smaller to larger clusters, which could be assigned to the structural transition of the clusters from planar to three-dimensional occurring at n = 4 to 5.

IMPROVEMENT TO THE MARGINAL COPING FIT OF COMMERCIALLY PURE TITANIUM CAST IN PHOSPHATE-BONDED INVESTMENT BY USING A SIMPLE PATTERN COATING TECHNIQUE

Statement of problem. Coatings of zirconite, Y2O3 or ZrO2 on wax patterns before investing in phosphate-bonded investments have been recommended to reduce the reaction layer in titanium castings, but they are not easily obtainable. Spinel-based investments are relatively stable with molten titanium and could be used as coatings to improve the quality of castings made with those investments. Purpose. The purpose of this study was to evaluate the effect of pattern coating with a commercial spinel-based investment before investing in 1 of 3 phosphate-bonded investments on the marginal coping fit and surface roughness of commercially pure titanium castings. Material and methods. Ten square acrylic resin patterns (12 x 12 x 2 mm) per group were invested in the phosphate-bonded investments Rematitan Plus (RP), Rema Exakt (RE), and Castorit Super C (CA) with or without a coating of the spinel-based investment, Rematitan Ultra (RU). After casting, the specimens were cleaned and the surface roughness was measured with a profilometer. Copings for dental implants with conical abutment were invested, eliminated, and cast as previously described. The copings were cleaned and misfit was measured with a profile projector (n=10). For both tests, the difference between the mean value of RU only and each value of the phosphate-bonded investment was calculated, and the data were analyzed by 2-way ANOVA and Tukey's HSD test (alpha=.05). In addition, the investment roughness was measured in bar specimens (30 x 10 x 10 mm), and the data (n=10) were analyzed by 1-way ANOVA and Tukey's HSD post hoc test (alpha=.05). Results. Two-way ANOVA for casting surface roughness was significant because of the investment, the coating technique, and the interaction between variables. One-way ANOVA was performed to prove the interaction term, and Tukey's post hoc test showed that RP with coating had the lowest mean, while RP had the highest. CA with coating was not different from RP with coating or CA without coating. RE with coating was similar to CA, while RE was different from all groups. For coping marginal fit, the 2-way ANOVA was significant for the investment, the coating technique, and the interaction between variables. The interaction was analyzed by1-way ANOVA and Tukey's HSD test that showed no significant difference among the coated groups, which had better marginal fit than the groups without coating. Among the groups without coating, CA had significant lower marginal misfit than RP, while RE was not different from CA and RP. For the investment surface roughness, the 1-way ANOVA was significant. CA and RU were smoother than RE and RP (P<.001). Conclusions. The coating technique improved the quality of castings fabricated with phosphate-bonded investments. (J Prosthet Dent 2012;108:51-57)