A flow-injection-ICP system sequential multielemental analysis with simultaneously mercury(II) preconcentration step

A flow-injection system for multielemental analysis with a mercury(II) preconcentration step using a resin Chelite-S(R)(Serva Feinbiochemica Heidelberg, Part No. 41709) packed minicolumn by inductively coupled plasma atomic emission spectroscopy is described. A mercury reductive elution procedure with a mixture of SnCl2/HCl was used, which allows use of 6 mol/L HCl solution instead of concentrated hydrochoric acid. The main parameters related to ICP operation, such as radio frequency power (950-1750 W), auxiliary argon flow (0.0-1.5 L/min) and spray chamber nebulizer pressure (15-35 psi), were studied. Optimization of the FIA system was reached by defining the best eluent carrier stream (1.4-2.8 mL/min), Hgdegrees carrier stream (10-40 mL min(-1)), loading time (0.5-4.0 min), sample flow rate (1.25-10.0 mL/min), temperature of reactor gas liquid separator (GLS) (25-75 degreesC) and eluent volume (50-350 muL). Throughput is around 30 samples per hour for analytical solutions within the range 50-2500 ng Hg(II)/L. Results from certified material showed good precision (RSD < 3%, n = 12) and no statistical difference was observed for real samples analyzed by AAS and by the proposed system.

AN ACTINOMETRIC STUDY OF C2H2 PLASMA POLYMERIZATION AND FILM PROPERTIES

Thin polymer films were grown in radio frequency discharges containing C2H2. Actinometry revealed the trend in the plasma concentration of the CH species as a function of the operating pressure. The C-H bond density in the films, revealed by infrared analysis, was found to increase with the pressure of C2H2 in a similar way to that of the concentration of the CH species in the discharge. From transmission ultraviolet-visible spectroscopy data, optical parameters of the polymers, namely, the refractive index and the optical gap, were calculated. For the range of pressure studied, the refractive index decreased from 1.73 to 1.63 and the optical gap increased from 2.4 to 3.3 eV. Finally, measurements of the residual stress of the polymer films were carried out by the bending beam method, using a He-Ne laser, yielding values from 0.05 to 0.3 GPa. (C) 1995 American Vacuum Society.

Effect of cold plasma treatment on mechanical properties of PET/PMMA composites

Mechanical strength of polyethylene terephthalate (PET) fibres and polymethyl methacrylate (PMMA) matrix composites were studied with particular interest on the effects of oxygen and argon plasma treated fibres. PET. fibres were treated in a radio frequency plasma reactor using argon or oxygen for different treatment times to increase the interface adhesion. Fibre volume fraction was measured through digital image analysis. Elastic moduli resulted between 3 GPa for untreated to 6 GPa for treated composites. Tensile tests on PET fibres showed that plasma treatment caused a decrease in average tensile strength compared to untreated fibres. Fracture analysis confirmed the increase in interfacial adhesion due to plasma treatment. (c) 2004 Elsevier Ltd. All rights reserved.

The effect of N+ ion energy on the properties of ion bombarded plasma polymer films

This work describes the influence of the ion bombardment on the electrical, optical and mechanical properties of polymer films deposited from radio-frequency plasmas of benzene. Irradiations were conducted using N+ at 5 x 10(19) ions/m(2), varying the ion energy, E-0, from 0 to 150 keV. Film elemental composition was determined by Rutherford backscattering spectroscopy. Electrical resistivity and hardness were obtained by the two-point probe and nanoindentation technique, respectively. Ultraviolet-visible spectroscopy was employed to investigate the optical constants of the samples. Etching rate was determined by exposure of the films to reactive oxygen plasmas. Ion bombardment induced gradual loss of H and increase in C and O concentrations with Eo. As a consequence the electrical, optical and mechanical properties were drastically affected. Interpretation of these results is proposed in terms of chain cross-linking and unsaturation. (C) 2001 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)

Plasma-deposition of Ag-containing polyethyleneoxide-like coatings

Ag-containing polyethyleneoxide (FEO)-like thin films have been deposited in Radio Frequency Glow Discharges fed with vapors of diethyleneglycol-dimethyl-ether and argon. Proper experimental conditions have been utilized in order to fragment the monomer in the glow and, at the same time, sputter Ag from the silver RF cathode of the reactor, in a way that polyethyleneoxide(PEO)-like coatings with embedded Ag clusters have been deposited at the ground electrode. The composition of the coatings has been investigated by means of different techniques; the plasma process has been investigated by means of Actinometric Optical Emission Spectroscopy. A correlation has been found between the amount of silver embedded in the coatings and that sputtered in the discharge, monitored by actinometry, that could eventually be utilized to control in situ the deposition process.

Estimativa do padrão de preferência térmica de matrizes pesadas (frango de corte)

Female broiler breeder productivity is based on the principles of thermal comfort that are directly related with the microclimate inside the housing. This research had the objective of monitoring the behavior of female broiler breeders, using the technology of radio-frequency, injectable transponders and readers in different existing microclimates inside a small scale distorted housing model. Eight birds with electronic identification were used. Three readers were used, in three different points inside the model: on the floor of the nest, in the passage besides the lateral wall and below the water facility. Dry bulb (DBT), wet bulb (WBT) and black globe (BGT) temperature were measured continuously. The results point out a distinct behavioral pattern of the birds regarding the environment exposition during the experiment. Three probabilistic models of behavior were developed from the recorded data: probabilistic model for the passage use: FP = 1.10 - 0.244 ln(DBT), probabilistic model for the water facility use: FB = 0.398 + 0.00866(DBT), and probabilistic model for the nest use: FN = 2.22 - 0.272 DBT + 0,011 DBT 2 - 0.000144 DBT 3.

Effect of collagenase ointment on a radiofrequency induced abrasive wound

• Aim: Radiofrequency is one of the methods used to treat wrinkles and skin lesions, but its application may result in an abrasive wound. The purpose of this study was to evaluate the effect of collagenase ointment on the epithelial healing of an abrasive wound induced by a radiofrequency system. • Methods: An abrasive wound was produced using radiofrequency at the dorsal midline of 30 guinea pigs, which were randomly divided into 2 groups: one group were treated with saline solution and the other group treated with collagenase ointment; both used twice daily. The animals were sacrificed at 1, 7, 15, 30 and 60 postoperative days. Macroscopic, histological and morphometric evaluations were performed and the results were submitted to statistical analysis. • Results: The animals treated with collagenase ointment presented accelerated healing process and less inflammatory cell infiltration than the saline solution treated animals from one to fifteen postoperative days. Morphometric evaluation showed a thicker epidermis and a thinner dermis layer in the saline solution group at one and seven postoperative days, but significant differences between both groups were not observed at thirty and sixty postoperative days. • Conclusion: According to our results the use of collagenase ointment may accelerate the healing process of a radiofrequency induced abrasive wound.

Evaluation of blood compatibility of plasma deposited heparin-like films and SF6 plasma treated surfaces

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

ENCORE: Enhanced Galileo code receiver for surveying applications

In this paper we describe the development of a low-cost high-accuracy Galileo Code receiver, user application software and positioning algorithms for land management applications, which have been implemented using a dedicated FPGA board and dual frequency Galileo E5/L1 Radio Frequency Front-End. The current situation of rural property surveying in Brazil is described and the use of code measurements from the new Galileo signals E5 AltBOC combined with E1 MBOC for use in land management applications is explored. We explain how such approach is expected to allow delivering an absolute positioning solution which could bridge the gap between receivers of high cost/complexity/accuracy based on carrier phase and receivers of lower cost/accuracy based on pseudorange observables. The system is presented together with a detailed description of main components: the Code Receiver and the Application Software. The work presented is part of an ongoing European-Brazilian consortium effort to explore the use of new Galileo for land management applications in Brazil and sponsored by the GNSS Supervisory Authority (GSA).

Remote laboratory experiment access via an RFID interface

In this paper, remote laboratory experiment access is considered through the use of radio frequency identification (RFID) technology. Contactless smart cards are used widely in many applications from travel cards through to building access control and inventory tracking. However, their use is considered here for access to electronic engineering experimentation in a remote laboratory setting by providing the ability to interface experiments through this contactless (wireless) connection means. A case study design is implemented to demonstrate such a means by incorporating experiment data onto a contactless smart card and accessing this via a card reader and web server arrangement. © 2012 IEEE.

Optical, mechanical and surface properties of amorphous carbonaceous thin films obtained by plasma enhanced chemical vapor deposition and plasma immersion ion implantation and deposition

Diverse amorphous hydrogenated carbon-based films (a-C:H, a-C:H:F, a-C:H:N, a-C:H:Cl and a-C:H:Si:O) were obtained by radiofrequency plasma enhanced chemical vapor deposition (PECVD) and plasma immersion ion implantation and deposition (PIIID). The same precursors were used in the production of each pair of each type of film, such as a-C:H, using both PECVD and PIIID. Optical properties, namely the refractive index, n, absorption coefficient, α, and optical gap, ETauc, of these films were obtained via transmission spectra in the ultraviolet-visible near-infrared range (wavelengths from 300 to 3300 nm). Film hardness, elastic modulus and stiffness were obtained as a function of depth using nano-indentation. Surface energy values were calculated from liquid drop contact angle data. Film roughness and morphology were assessed using atomic force microscopy (AFM). The PIIID films were usually thinner and possessed higher refractive indices than the PECVD films. Determined refractive indices are consistent with literature values for similar types of films. Values of ETauc were increased in the PIIID films compared to the PECVD films. An exception was the a-C:H:Si:O films, for which that obtained by PIIID was thicker and exhibited a decreased ETauc. The mechanical properties - hardness, elastic modulus and stiffness - of films produced by PECVD and PIIID generally present small differences. An interesting effect is the increase in the hardness of a-C:H:Cl films from 1.0 to 3.0 GPa when ion implantation is employed. Surface energy correlates well with surface roughness. The implanted films are usually smoother than those obtained by PECVD. ©2013 Elsevier B.V. All rights reserved.

Estimativa do vapor d'água atmosférico e avaliação da modelagem do atraso zenital troposférico utilizando GPS

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

Adesão bacteriana em braquetes metálicos com tratamento de superfície: estudo in vitro

Pós-graduação em Engenharia Mecânica - FEG

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

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)