Biomechanical Study in Polyurethane Mandibles of Different Metal Plates and Internal Fixation Techniques, Employed in Mandibular Angle Fractures

The aim of this study was to perform a physicochemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures. Twenty-eight polyurethane mandibles were uniformly sectioned on the left angle. These were divided into 4 groups: group Eng 1P, one 2.0-mm plate and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates, the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the Ti-15Mo alloy. Each group was subjected to linear vertical loading at the first molar on the plated side in a mechanical testing unit. Means and standard deviations were compared with respect to statistical significance using ANOVA. The chemical composition of the Ti-15Mo alloy was close to the nominal value. The mapping of Mo and Ti showed a homogeneous distribution. SEM of the screw revealed machining debris. For the plates, only the cpTi plate undergoes a surface treatment. The metallographic analysis reveals granular microstructure, from the thermomechanical trials. A statistically significant difference was found (P < 0.05) when the comparison between both internal fixation techniques was performed. The 2P technique showed better mechanical behavior than 1P.

Elementos-traço em dois latossolos após aplicações anuais de lodo de esgoto por treze anos

This experiment aim was to evaluate the contamination of the trace elements (TE) arsenic, barium, cadmium, chromium, copper, mercury, molybdenum, nickel, lead, selenium, and zinc considered in the CONAMA resolution 375 after 13 years long using sewage sludge (SS) as fertilizer in two soils: an Eutroferric Clayed Red Latosol (Rhodic Eutrudox - RE) and a Dystrophic Red Latosol (Typic Haplorthox - TH). Experiment in the field under maize cultivation had four treatments (0, 5, 10, and 20 t of SS ha(-1), dry weight), five replications and an experimental design in randomized blocks. The agrochemicals (dolomitic limestone, single superphosphate, and potassium chloride), SS, soils, and the certified reference materials were digested according to the USEPA 3051A method and the chemical elements were quantified by ICP OES. The TE contents found in the agrochemicals used should not cause immediate environmental impact. The higher TE values were found in the RE and they did not reach the agricultural (more stringent) Investigation Level (IL) yet, according to 420 CONAMA resolution. Persisting the actual SS fertilization amount applied in the soil and the TE concentration in the SS is foreseen that Ba, Cd, Cr, Cu, Ni, and Zn will be the first elements to reach the IL in the RE.

Uso do método de Monte Carlo para simulação e detecção do espectro de raios-X gerado com feixes de elétrons em alvo de Molibdênio, utilizando o Geant4

The huge demand for procedures involving ionizing radiation promotes the need for safe methods of experimentation considering the danger of their biological e ects with consequent risk to humans. Brazilian's legislation prohibits experiments involving this type of radiation in humans through Decree 453 of Ministry of Health with determines that such procedures comply with the principles of justi cation, optimization and dose limitation. In this line, concurrently with the advancement of available computer processing power, computing simulations have become relevant in those situations where experimental procedures are too cost or impractical. The Monte Carlo method, created along the Manhattan Project duringWorldWar II, is a powerful strategy to simulations in computational physics. In medical physics, this technique has been extensively used with applications in diagnostics and cancer treatment. The objective of this work is to simulate the production and detection of X-rays for the energy range of diagnostic radiology, for molybdenum target, using the Geant4 toolkit. X-ray tubes with this kind of target material are used in diagnostic radiology, speci cally in mammography, one of the most used techniques for screening of breast cancer in women. During the simulations, we used di erent models for bremsstrahlung available in physical models for low energy, in situations already covered by the literature in earlier versions of Geant4. Our results show that although the physical situations seems qualitatively adequate, quantitative comparisons to available analytical data shows aws in the code of Geant4 Low Energy source

Implementação de um tuboexpansor na refinaria do Planalto Paulista – REPLAN com objetivo do aproveitamento da energia contida nos gases residuais do FCC – Fluid Catalytic Cracking na geração de energia elétrica

The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading

Alterações microestruturais decorrentes dos sucessivos reparos de solda TIG aplicados ao longo da vida útil de uma estrutura aeronáutica crítica à segurança de vôo

The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading

Desenvolvimento de aplicativo de análise técnica e econômica para adaptação de uma roda d’água acionada por cima para geração de energia elétrica no meio rural

The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading

Doses de molibdênio e nitrogênio em milho safrinha e efeito residual na cultura da soja em plantio direto

Pós-graduação em Agronomia - FEIS

Produção e posterior semeadura de sementes de soja enriquecida com molibdênio: qualidade fisiológica, alterações químicas e nutricionais, métodos e épocas de aplicação

Pós-graduação em Agronomia - FEIS

Efeito de elementos susbstitucionais e intersticiais nas propriedades mecânicas e na biocompatibilidade de ligas do sistema Ti-15Zr-xMo

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

Stress distribution in delayed replanted teeth splinted with different orthodontic wires: a three-dimensional finite element analysis

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

Effect of recasting procedure upon corrosion behavior and metallic ion release of Co-Cr-Mo dental alloy in physiological

Recasting process influence upon corrosion behavior of Co-Cr-Mo dental alloy in simulated physiological serum has been investigated using chemical and electrochemical techniques. Recast Co-Cr-Mo alloy by induction (IND) or by blowtorch (FLAME) has exhibited similar dendritic structures. Both IND and FLAME alloys have presented good corrosion resistance in physiological serum. Passivation process provides this corrosion resistance. Codissolution makes this process difficult. Passive films, formed on these alloys, have been analyzed as a dual layer consisting of an inner barrier and an outer porous layer. Passive film protective characteristics are higher in FLAME than in IND alloy. On this last alloy, the passive film is more porous due to a higher Codissolution. ©Carl Hanser Verlag, München.

Synthesis and characterization of an antibacterial and non-toxic dimeric peptide derived from the C-terminal region of Bothropstoxin-I

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

Crystal structure of mature 2S albumin from Moringa oleifera seeds

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

Structure, microstructure, and selected mechanical properties of Ti-Zr-Mo alloys for biomedical applications

New titanium alloys for biomedical applications have been developed primarily with the addition of Nb, Ta, Mo, and Zr, because those elements stabilize the β phase and they don’t cause cytotoxicity in the organism. The objective of this paper is to analyze the effect of molybdenum on the structure, microstructure, and selected mechanical properties of Ti-15Zr-xMo (x = 5, 10, 15, and 20 wt%) alloys. The samples were produced in an arc-melting furnace with inert argon atmosphere, and they were hot-rolled and homogenized. The samples were characterized using chemical, structural, and microstructural analysis. The mechanical analysis was made using Vickers microhardness and Young’s modulus measurements. The compositions of the alloys were sensitive to the molybdenum concentration, indicating the presence of α’+α”+β phases in the Ti-15Zr-5Mo alloy, α”+β in the Ti-15Zr-10Mo alloy, and β phase in the Ti-15Zr-15Mo and Ti-15Zr-20Mo alloys. The mechanical properties showed favorable values for biomedical application in the alloys presenting high hardness and low Young’s modulus compared with CP-Ti.

Effect of the substitutional elements on the microstructure of the Ti-15Mo-Zr and Ti-15Zr-Mo systems alloys

Titanium alloys have excellent biocompatibility, and combined with their low elastic modulus, become more efficient when applied in orthopedic prostheses. Samples of Ti-15Mo-Zr and Ti-15Zr-Mo system alloys were prepared using an arc-melting furnace with argon atmosphere. The chemical quantitative analysis was performed using an optical emission spectrometer with inductively coupled plasma and thermal conductivity difference. The X-ray diffractograms, allied with optical microscopy, revealed the structure and microstructure of the samples. The mechanical analysis was evaluated by Vickers microhardness measurements. The structure and microstructure of alloys were sensitive to molybdenum and zirconium concentration, presenting α′, α″ and β phases. Molybdenum proved to have greater β-stabilizer action than zirconium. Microhardness was changed with addition of molybdenum and zirconium, having Ti-15Zr-10Mo (436 ± 2 HV) and Ti-15Mo-10Zr (378 ± 4 HV) the highest values in each system.