Crystallographic structure of Ti-6Al-4V, Ti-HP and Ti-CP under high-pressure

The phase stability of a commercial purity (Ti-CP), high purity (Ti-HP) and Ti-6Al-4V alloy were investigated in a diamond anvil cell up to 32 GPa and 298 K using a polychromatic X-ray beam. The Ti-CP and Ti-HP shown the same HCP (c/a∼0.632) to Hexagonal (c/a∼1.63) non reversible martensitic transition at about 9 GPa. The as received Ti-6Al-4V shows a very low relative volume fraction β-Ti / α-Ti. No phase changes were observed in the Ti-6Al-4V alloy in the pressure range of this study. The α phase of the Ti-6Al-4V shows monotonic volume cell pressure dependence. This volume change is reversible and non-hysteretic. The cell of the a phase recovered its original volume when the pressure was released. © 2010 IOP Publishing Ltd.

Efficiency evaluation of ZrB2 incorporation in the MgB 2 matrix phase using high-energy milling

The present study suggests the use of high energy ball milling to mix (to dope) the phase MgB2 with the AlB2 crystalline structure compound, ZrB2, with the same C32 hexagonal structure than MgB 2, in different concentrations, enabling the maintenance of the crystalline phase structures practically unaffected and the efficient mixture with the dopant. The high energy ball milling was performed with different ball-to-powder ratios. The analysis of the transformation and formation of phases was accomplished by X-ray diffractometry (XRD), using the Rietveld method, and scanning electron microscopy. As the high energy ball milling reduced the crystallinity of the milled compounds, also reducing the size of the particles, the XRD analysis were influenced, and they could be used as comparative and control method of the milling. Aiming the recovery of crystallinity, homogenization and final phase formation, heat treatments were performed, enabling that crystalline phases, changed during milling, could be obtained again in the final product. © (2010) Trans Tech Publications.

Profile evaluation of orthodontic professionals as for their legal actions

Objective: Evaluate the legal actions and behavior in the doctor/patient relationship, used by dental surgeons practicing orthodontics. Methods: The population sample of the present study consisted of dental surgeons, active in the field of orthodontics, and registered with Dental Press Publishing Company - Maringá/PR, Brazil, with a total sample size of 525 professionals. The research was conducted using a 17-question survey forwarded to these professionals. Results and Conclusions: The majority of participants in our study are specialized in orthodontics; 75% of professionals use some sort of contract at the office/clinic; 73.7% of professionals periodically request maintenance X-rays; a large percentage of professionals (58.9%) keep patient records on file for life. The interviewed professionals demonstrate good knowledge of the Brazilian Code of Ethics in Dentistry, especially of Chapter XIV - on Communication.

A simple procedure for the preparation of laponite and thermoplastic starch nanocomposites: Structural, mechanical, and thermal characterizations

The aim of this article is to propose advances for the preparation of hybrid nanocomposites prepared by the combination of intercalation from solution and melt-processing methods. This research investigates the effect of the laponite RDS content on the thermal, structural, and mechanical properties of thermoplastic starch (TPS). X-ray diffraction was performed to investigate the dispersion of the laponite RDS layers into the TPS matrix. The results show good nanodispersion, intercalation, and exfoliation of the clay platelets, indicating that these composites are true nanocomposites. The presence of laponite RDS also improves the thermal stability and mechanical properties of the TPSmatrix due to its reinforcement effect which was optimized by the high degree of exfoliation of the clay. Thus, these results indicate that the exfoliated TPS-laponite nanocomposites have great potential for industrial applications and, more specifically, in the packaging field. © The Author(s) 2011 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Influence of anatomical location on CT numbers in cone beam computed tomography

Objective: To assess the influence of anatomical location on computed tomography (CT) numbers in mid- and full field of view (FOV) cone beam computed tomography (CBCT) scans. Study Design: Polypropylene tubes with varying concentrations of dipotassium hydrogen phosphate (K2HPO4) solutions (50-1200 mg/mL) were imaged within the incisor, premolar, and molar dental sockets of a human skull phantom. CBCT scans were acquired using the NewTom 3G and NewTom 5G units. The CT numbers of the K2HPO 4 phantoms were measured, and the relationship between CT numbers and K2HPO4 concentration was examined. The measured CT numbers of the K2HPO4 phantoms were compared between anatomical sites. Results: At all six anatomical locations, there was a strong linear relationship between CT numbers and K2HPO4 concentration (R 2 > 0.93). However, the absolute CT numbers varied considerably with the anatomical location. Conclusion: The relationship between CT numbers and object density is not uniform through the dental arch on CBCT scans. © 2013 Elsevier Inc.

Enfisema lobar congênito: série de casos de 30 anos em dois hospitais universitários

Objetivo: Revisar os casos de enfisema lobar congênito (ELC) operados nos últimos 30 anos em dois hospitais universitários. Métodos: Foram revistos os prontuários médicos das crianças com ELC operadas no Hospital das Clínicas da Faculdade de Medicina de Botucatu e no Hospital da Universidade de Mogi das Cruzes entre 1979 e 2009. Dados sobre sintomas, exame físico, achados radiológicos, diagnóstico, tratamento cirúrgico e seguimento pós-operatório mediato e tardio foram analisados. Resultados: Durante o período estudado, 20 crianças com ELC foram submetidas a tratamento cirúrgico. A média de idade dos pacientes no momento da cirurgia foi 6,9 meses (variação, 9 dias a 4 anos). Todos os casos apresentaram sintomas ao nascimento ou nos primeiros meses de vida. Em todos os casos, a radiografia simples de tórax foi importante na definição do diagnóstico. Em casos de dificuldade respiratória moderada, a TC de tórax auxiliou no diagnóstico. Um paciente com desconforto respiratório grave foi diagnosticado erroneamente com pneumotórax hipertensivo e submetido a drenagem torácica. A broncoscopia só foi realizada nos pacientes com dificuldade respiratória moderada e não foram encontrados sinais de anomalias traqueobrônquicas. A abordagem cirúrgica foi realizada através de toracotomia lateral poupadora de músculo. O lobo superior esquerdo e o lobo médio foram os mais afetados, seguidos pelo lobo superior direito. A lobectomia foi realizada em 18 casos, enquanto a bilobectomia foi realizada em 2 casos (com ressecção de cisto broncogênico em 1 desses). Complicações pós-operatórias não foram observadas. O acompanhamento pós-operatório foi de pelo menos 24 meses (média, 60 meses) e não foram observadas complicações tardias nesta série. Conclusões: O ELC é uma doença pouco comum, ainda negligenciada, de etiologia incerta, mas de fácil diagnóstico radiológico e tratamento cirúrgico eficaz.

Effect of Na-chloride on the bioleaching of a chalcopyrite concentrate in shake flasks and stirred tank bioreactors

Oxidative dissolution of chalcopyrite at ambient temperatures is generally slow and subject to passivation, posing a major challenge for developing bioleaching applications for this recalcitrant mineral. Chloride is known to enhance the chemical leaching of chalcopyrite, but much of this effect has been demonstrated at elevated temperatures. This study was undertaken to test whether 100-200 mM Na-chloride enhances the chemical and bacterial leaching of chalcopyrite in shake flasks and stirred tank bioreactor conditions at mesophilic temperatures. Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and abiotic controls were employed for the leaching experiments. Addition of Na-chloride to the bioleaching suspension inhibited the formation of secondary phases from chalcopyrite and decreased the Fe(III) precipitation. Neither elemental S nor secondary Cu-sulfides were detected in solid residues by X-ray diffraction. Chalcopyrite leaching was enhanced when the solution contained bacteria, ferrous iron and Na-chloride under low redox potential (< 450 mV) conditions. Scanning electron micrographs and energy-dispersive analysis of X-rays revealed the presence of precipitates that were identified as brushite and jarosites in solid residues. Minor amounts of gypsum may also have been present. Electrochemical analysis of solid residues was in concurrence of the differential effects between chemical controls, chloride ions, and bacteria. Electrochemical impedance spectroscopy was used to characterize interfacial changes on chalcopyrite surface caused by different bioleaching conditions. In abiotic controls, the impedance signal stabilized after 28 days, indicating the lack of changes on mineral surface thereafter, but with more resistive behavior than chalcopyrite itself. For bioleached samples, the signal suggested some capacitive response with time owing to the formation of less conductive precipitates. At Bode-phase angle plots (middle frequency), a new time constant was observed that was associated with the formation of jarosite, possibly also with minor amount or elemental S, although this intermediate could not be verified by XRD. Real impedance vs. frequency plots indicated that the bioleaching continued to modify the chalcopyrite/solution interface even after 42 days. © 2013 The Authors.

Biossolubilização da calcopirita na presença dos íons cloreto e ácidos orgânicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aplicação do Método de Rietveld em caracterização estrutural e nanoestrutural do espinélio 'Ni IND. 1'- 'delta' Co'delta''Fe IND.2''O IND.4' preparado por reação de combustão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aspectos clínicos e radiográficos da coluna cervical de bezerros submetidos a Prova do Laço

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação comparativa de diferentes meios para o diagnóstico em endodontia

Pós-graduação em Odontologia - FOAR

Utilização do pó de pedra basáltica em substituição à areia natural do concreto

Pós-graduação em Engenharia Civil - FEIS

Avaliação de implantes dentários da liga experimental Ti-30Ta após tratamento de superfície biomimético e imobilização com bisfosfonato

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

Ferritas 'MG IND. 1' - 'delta'ZN''delta''FE' IND. 2'O IND. 4' obtidas por síntese de reação de combustão: caracterização estrutural e nanoestrutural

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

Desenvolvimento de sistemas líquido-cristalinos multifuncionais contendo nanopartículas de TiO2 para proteção solar e liberação controlada de terpinem-4-ol

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