Analysis of cement slurries by inductively coupled plasma optical emission spectrometry with axial viewing

The feasibility of Portland cement analysis by introduction of slurries in an inductively coupled plasma optical emission spectrometer (ICP-OES) with axial viewing has been evaluated. After a fast manual grinding of the cement samples, owing to the pulverized state of this material, 0.1% m/v slurries were prepared in 1% v/v HCl. The calibration was performed adopting two strategies: one based on slurries prepared from different masses (50, 75, 100 and 125 mg) of a Portland cement standard reference material (NIST SRM 1881), and the other one based on aqueous reference solutions. A complete analysis of cement for major (Al, Ca, Fe, Mg and Si), minor and trace elements (Mn, P, S, Sr and Ti) was accomplished. Both strategies led to accurate results for commercial Portland cement samples, except for Si and Ti. for which the calibration with aqueous reference solutions resulted in low values. Applying a paired t-test it was shown that most results were in agreement at a 95% confidence level with a conventional fusion decomposition procedure. The ICP-OES with axial viewing and end-on gas configuration for removal of the recombination plasma zone was effective for cement slurry analysis without any undesirable particle deposition in the pre-optics interface and without severe spectral interferences. (C) 2002 Elsevier B.V. B.V. All rights reserved.

A Novel Plasma Technique for Surface Treatment: The Plasma Expander

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

HMDSO plasma polymerization and thin film optical properties

Thin films were deposited from hexamethyldisiloxane (HMDSO) in a glow discharge supplied with radiofrequency (rf) power. Actino-metric optical emission spectroscopy was used to follow trends in the plasma concentrations of the species SiH (414.2 nm), CH (431.4 nm), CO (520.0 nm), and H (656.3 nm) as a function of the applied rf power (range 5 to 35 W). Transmission infrared spectroscopy (IRS) was employed to characterize the molecular structure of the polymer, showing the presence of Si-H, Si-O-Si, Si-O-C and C-H groups. The deposition rate, determined by optical interferometry, ranged from 60 to 130 nm/min. Optical properties were determined from transmission ultra violet-visible spectroscopy (UVS) data. The absorption coefficient α, the refractive index n, and the optical gap E04 of the polymer films were calculated as a function of the applied power. The refractive index at a photon energy of 1 eV varied from 1.45 to 1.55, depending on the rf power used for the deposition. The absorption coefficient showed an absorption edge similar to other non-crystalline materials, amorphous hydrogenated carbon, and semiconductors. For our samples, we define as an optical gap, the photon energy E04 corresponding to the energy at an absorption of 104 cm-1. The values of E04 decreased from 5.3 to 4.6 as the rf power was increased from 5 to 35 W. © 1995.

Comportamento do implante contendo bone morphogenetic protein (bmp) associado ao plasma rico em plaquetas na reparação de fraturas orbitárias

Purpose: This study intends to evaluate BMP (Bone Morphogenetic Protein) implant and BMP implant plus PRP (Platelet Rich Plasma) in rabbit orbital fractures, searching for tissue reaction, by radiological and morfometrical analysis. Methods:Third six white rabbits were submitted to orbital floor fracture and distributed in three groups: G1, with rabbits receiving a plate containing decalcified bone matrix and BMP; G2, with rabbits receiving the implant with BMP wrapped by PRP; G3, the control group where it was made the fracture only. The animals were evaluated radiologically after surgery and at sacrifice time in 7, 30, 90 and 180th day after surgery. After sacrifice, a block containing the right orbital tissue was extracted and prepared to morphological and morphometrical analysis. Results: An intensive linfomononuclear inflammatory reaction was observed at 7th day in G1 e G2, witch decreased after the 30th day; mesenchimal cells, osteoblasts, new bone and progressive cavitation of the implant were also observed, besides signs of calcium deposition by radiological study. In the control group fibrosis at the site of fracture was identified only. Conclusion: BMP seemed a good orbital implant producing new bone at the implant site and correcting bone defect.There was not observed acceleration of osteoinduction when the implant was associated with PRP.

BMP implant associated with platelet-rich plasma in orbit fracture repair

Purpose: To evaluate a bone morphogenetic protein (BMP) implant with and without platelet-rich plasma (PRP), which is supposed to accelerate fracture consolidation in the orbit fracture treatment. Methods: Thirty-six white rabbits were subjected to orbital fracture and treated in three groups: BMP implant fracture repair (G1), BMP plus PRP implant fracture repair (G2), and fracture and spontaneous repair (G3). The animals were sacrificed at 7, 30, 90, and 180 days after surgery. A radiology evaluation was carried out on the 7th day after the fracture and at the sacrifice moments. After the animals' death, the orbital content material was removed and prepared for morphological and morphometric analysis. Results: Radiology suggested intramembranous and progressive cavitation and ossification without a reduction in implant size and with signs of calcium deposition; these events were confirmed by histological analysis, which showed a lymphomononuclear inflammatory reaction in G1 and G2, more intense 7 days after surgery and reducing after 30 days. Associating PRP with BMP did not accelerate bone induction. Conclusion: BMP implant promotes bone induction, integration at fracture site, scarce inflammatory reaction, and may be a good alternative in orbit fracture reconstruction. The addition of PRP to the BMP plate did not accelerate the resolution, and its use is not necessary. Copyright © Informa Healthcare USA, Inc.

Plasma-polymerized acetylene nanofilms modified by nitrogen ion implantation

Thin films were prepared by plasma enhanced chemical vapour deposition (PECVD) from a mixture of acetylene and argon, and post deposition-treated by plasma immersion ion implantation (PIII). The effect of PIII on the nanofilms properties was evaluated as a function of treatment time. The average thickness and roughness were diminished upon PIII. On the other hand, hardness (0.7-3.9 GPa) and elastic modulus (29-54 GPa) increased upon 60 min of ion bombardment. Such results are ascribed mainly to the densification of the film structure caused by the increment in the crosslinking degree with increasing the energy deposited in the films. Wettability of the samples, investigated by contact angle measurements, was reduced (from 64 to 21°) right after PIII. This result, attributed to the introduction of polar groups in the film structure, was not preserved as the sample was aged in atmosphere. After aging, contact angles were larger than 70° but still smaller than 90°. Although the wettability has decreased with aging, the hydrophilic character of the samples was preserved. For certain treatment times, nitrogen PIII turned the plasma-polymerized acetylene films smoother, denser, mechanically and tribologicaly more resistant than the as-deposited material. © 2013 Elsevier B.V.

Preparation of films from aluminum acetylacetonate by plasma sputtering

Aluminum acetylacetonate has been reported as a precursor for the deposition of alumina films using different approaches. In this work, alumina-containing films were prepared by plasma sputtering this compound, spread directly on the powered lowermost electrode of a reactor, while grounding the substrates mounted on the topmost electrode. Radiofrequency power (13.56 MHz) was used to excite the plasma from argon atmosphere at a working pressure of 11 Pa. The effect of the plasma excitation power on the properties of the resulting films was studied. Film thickness and hardness were measured by profilometry and nanoindentation, respectively. The molecular structure and chemical composition of the layers were analyzed by Fourier transform infrared spectroscopy and energy dispersive spectroscopy. Surface micrographs, obtained by scanning electron microscopy, allowed the determination of the sample morphology. Grazing incidence X-ray diffraction was employed to determine the structure of the films. Amorphous organic layers were deposited with thicknesses of up to 7 μm and hardness of around 1.0 GPa. The films were composed by aluminum, carbon, oxygen and hydrogen, their proportions being strongly dependent on the power used to excite the plasma. A uniform surface was obtained for low-power depositions, but particulates and cracks appeared in the high-power prepared materials. The presence of different proportions of aluminum oxide in the coatings is ascribed to the different activations promoted in the metalorganic molecule once in the plasma phase. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

Si-based thin film coating on Y-TZP: Influence of deposition parameters on adhesion of resin cement

This study evaluated the influence of deposition parameters for Si-based thin films using magnetron sputtering for coating zirconia and subsequent adhesion of resin cement. Zirconia ceramic blocks were randomly divided into 8 groups and specimens were either ground finished and polished or conditioned using air-abrasion with alumina particles coated with silica. In the remaining groups, the polished specimens were coated with Si-based film coating with argon/oxygen magnetron discharge at 8:1 or 20:1 flux. In one group, Si-based film coating was performed on air-abraded surfaces. After application of bonding agent, resin cement was bonded. Profilometry, goniometry, Energy Dispersive X-ray Spectroscopy and Rutherford Backscattering Spectroscopy analysis were performed on the conditioned zirconia surfaces. Adhesion of resin cement to zirconia was tested using shear bond test and debonded surfaces were examined using Scanning Electron Microscopy. Si-based film coating applied on air-abraded rough zirconia surfaces increased the adhesion of the resin cement (22.78 ± 5.2 MPa) compared to those of other methods (0-14.62 MPa) (p = 0.05). Mixed type of failures were more frequent in Si film coated groups on either polished or air-abraded groups. Si-based thin films increased wettability compared to the control group but did not change the roughness, considering the parameters evaluated. Deposition parameters of Si-based thin film and after application of air-abrasion influenced the initial adhesion of resin cement to zirconia. © 2013 Elsevier B.V. All rights reserved.

Estudo das propriedades de barreira de filmes depositados a plasma sobre a liga de alumínio 2024

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Deposição de filmes por plasma eletrolítico em ligas de alumínio

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Investigação da temperatura eletrônica da fase plasma e estudo da morfologia, estrutura molecular e crescimento do polímero proveniente de um plasma de benzeno excitado por tensão contínua

Pós-graduação em Física - FEG

Filmes finos obtidos a plasma em reagentes contendo ácido cítrico/etilenoglicol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Propriedades químicas e ópticas de filmes de carbono amorfo halogenados produzidos por deposição a vapor químico assistido por plasma (PECVD) e deposição e implantação iônica por imersão em plasma (DIIIP)

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Propriedades mecânicas e tribológicas de filmes sintetizados mediante técnica de deposição e implantação iônica por imersão em plasma

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Filmes orgânicos contendo óxido de alumínio depositados a plasma

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)