Prediction of soluble solids in pulp of 92 samples of guava (Psidium guajava L.) and (Psidium friedrichsthalianum) in two maturity stages was made by using NIRS technique (near infrared reflectance spectroscopy). Each fruit was processed to obtain the edible fraction in which it was determined the soluble solids content (%). Two subsamples were taken and scanned in NIR spectrophotometer at the range of 400 to 2500 nm. Calibration regression models were generated by using MPLS (modified partial least squares) at the range of 1108 - 2498.2 nm. For the choice of the final model of the NIR calibration the criteria considered were the coefficient of determination (R 2 ) and the residual predictive deviation (RPD). Analysis of variance and mean test employing the statistical program SAS v 9.0 were realized in order to establish differences in the results obtained by the primary or reference method and NIR. The results showed a high predictive power of the model (R 2 = 0.990) when compared the primary and NIR measurements. The RPD value was 6.20, indicating excellent prediction accuracy. Primary estimates and NIR not showed significant differences. However there were significant differences at level of samples.

Due to its extensive field of application in different areas, including mechanics, electronics, tribology and optics the last decade has seen a large interest the study of titanium–zirconium–nitride (Ti–Zr)N thin films grown by different techniques. We had produced (Ti–Zr)N thin films and in this work chemical, morphological and electronics analysis are presented. Thin films were produced by the PAPVD (plasma assisted physics vapor deposition) technique, by pulsed arc in a mono-vaporizer system using a titanium–zirconium target with 99.99% purity. Argon–nitrogen mixture for the discharge was used. For the analyses X-ray photoelectron spectroscopy (XPS) and scanning probe microscopy (SPM) techniques were used, XPS results shown the chemical composition of the films. Films were morphologically and tribologically characterized using SPM, obtaining grain size and friction coefficient.

A new family of Transition Metallic Nitrides (5d Transition Metal with Nitrogen, NMT) has been produced by Plasma Assisted System. In this work an arc pulsed - Plasma Assisted Physical Vapor Deposition system (PAPVD) to grow Gold Nitride thin films (AuN) was used. The binding energies of 398.1 eV, 84.7 eV and 88.36 eV, to N1s and Au4f nar- row spectrum respectively were determined trough X-Ray Photoelectron Spectroscopy (XPS). Additionally using X- Ray Diffraction (XRD) a widening of the Au Bragg diffraction lines was observed, which could be attributed to new phases produced for inclution of nitrogen atom inside Au lattice. Using Atomic Force Microscopy (AFM) the granular character of the samples was verified and the grain sizes were determined. Additionally the conductive character of these samples was observed by Scanning Tunnel Microscopy (STM).

TiC thin films were grown on 304 stainless steel substrates using the cathodic arc discharge (CAD) technique. Titanium (6N) was placed in the cathodic electrode and the substrate was placed on the anode, besides this electrode is a furnace. The substrate temperature was varied between 50 and 250 degrees C with increases of 50 degrees C. For producing the discharge, a critical damping RLC (C = 0.54 mF, L = 2.3 mH and R = 0.46 m Omega) circuit was employed. To grow the TiC films, methane was used at a pressure of 3 mbar and a discharge voltage of 270V. X-ray diffraction (XRD) showed the TiC-phase with broad peaks and low intensities, however, the films have a crystallographic texture coefficient for (111)-orientation. Using the Scherrer equation both the crystallite size and microstrain were determined. The crystallite size increased as a function of substrate temperature. Using x-ray photoelectron spectroscopy (XPS) technique, amorphous carbon and TiC were identified. Profiler depth was realized for identifying the distribution of both compounds in the film.

A new family of Transition Metallic Nitrides (5d Transition Metal with Nitrogen, NMT) has been produced by Plasma Assisted System. In this work an arc pulsed - Plasma Assisted Physical Vapor Deposition system (PAPVD) to grow Gold Nitride thin films (AuN) was used. The binding energies of 398.1 eV, 84.7 eV and 88.36 eV, to Nls and Au4f narrow spectrum respectively were determined trough X-Ray Photoelectron Spectroscopy (XPS). Additionally using XRay Diffraction (XRD) a widening of the Au Bragg diffraction lines was observed, which could be attributed to new phases produced for inclution of nitrogen atom inside Au lattice. Using Atomic Force Microscopy (AFM) the granular character of the samples was verified and the grain sizes were determined. Additionally the conductive character of these samples was observed by Scanning Tunnel Microscopy (STM).

In this work, we performed two-dimensional hybrid (kinetic particle ions, massless fluid electrons) studies of collisionless magnetic reconnection on tearing mode, which is characteristic of magnetosphere and high temperature fusion device plasmas. Results include the full electron pressure tensor (instead of a localized resistivity) in the generalized Ohm's law to initiate reconnection, and an initial perturbation to the Harris equilibrium is applied. It was found that the reconnection rate has similar results to those obtained on magnetohydrodynamic (MHD) models and kinetic models.

AuN films were produced through the PAPVD (Plasma Assisted Physics Vapor Deposition) method, using the pulsed arc technique in a mono-vaporizer noncommercial system, which consists of a chamber with two faced electrodes, and a power controlled system. In order to obtain the films, an Au Target with 99% purity and stainless steel 304 were used as target and substrate respectively. Nitrogen was injected in gaseous phase at 2.3 mbar pressure, and a discharge of 160 V was performed, supplied by the power controlled source. Au4f and N1s narrow spectra were analyzed using XPS (X-ray Photoelectron Spectroscopy). (C) 2006 Elsevier Inc. All rights reserved.

(TiAl)N Films were grown on H13 steel by a plasma assisted repetitive pulsed arc discharge. To grow the coatings, a TiAl sintered cathode was used, 50% Ti-50% Al. The deposition system consists of a reaction chamber with two electrodes placed face to face. A pulsed power supply, which allows for control of parameters like time active arc, time between arcs, arc energy, and others, is used to generate the discharge. Thermal changes were carried out on H13 steel before and after growing the (TiAl)N films. X-ray diffraction (XRD) was employed to study the coatings, observing the H13 steel and (TiAl)N oxidation temperature. Morphological characteristics were analyzed by means of an Atomic Force Microscopy (AFM). Scanning electron microscopy (SEM) revealed the surface chemical composition of the films and morphological details of the samples. (C) 2007 Published by Elsevier Inc.

Gold nitride (AuN) is a recently synthesized component and is being studied for properties like optical, electrical and mechanical. Plasma-assisted physical vapor deposition (PAPVD) in pulsed arc system is used for deposition of AuN thin film. The system is formed of a reactor in which there are two faced electrodes, and a power-controlled system that performs the discharge systematically. Chemical analyses were realized by x-ray photoelectron spectroscopy (XPS) technique, and narrow N 1s and Au 4f spectra are shown using film stoichiometry, and I-V curves were obtained in two ways (substrate-film and film-substrate), to observe the electrical properties.

Graded coatings have the advantage of having gradual properties such as thermal expansion coefficient and lattice parameter, avoiding adherence problems due to good match between their component materials. In this work, some properties of coatings grown in graded form are presented. The materials were produced using the sputtering dc technique because of its facility to control the deposition parameters and generate homogeneous growth. The target is a disc of titanium and the samples are made of stainless steel 304. The working gases are argon, nitrogen and methane, which are mixed according to the material to be produced. Titatnium (Ti) layer is grown with argon, the titanium nitride (TiN) film is produced with a mixture of argon and nitrogen, and the titanium nitride carbon (TiCN) material is obtained mixing argon (Ar), nitrogen (N-2) and methane (CH4). These materials are characterized with scanning probe microscopy (SPM) in atomic force microscopy (AFM) mode in order to determine grain size and with x-ray photoelectron spectroscopy (XPS) studying the chemical composition and performing depth profiles.

The superficial characterization of epicarp of the coffee fruits was made in two states of development: mature and green. The roughness of the area, and also the line for the parameters of roughness average (Ra) and quadratic root average of the roughness (Rq), were found by means of atomic force microscopy (AFM). In addition, the densities and dimensions of the coffee cells were found. The Ra range of the mature fruit was found to be between 0.03 and 0.19μm, and for the green fruit it was between 0.23 and 0.38μm. The Rq range of the mature fruit was found to be between 0.05 and 0.24μm, and for the green fruit it was between 0.29 and 0.49μm. These values delimit ranges of roughness for each state of development analyzed, and there is a difference among them without appearing interpolation of the data. It was determined that the cells have ellipsoidal form with an average area of 194.62μm2, and the density average is 4.206cell/mm2.

Amorphous B"4C and BC"2N films were prepared on (111) silicon substrates by reactive laser ablation using a B"4C target. For the depositions of BC"2N a nitrogen pressure of 63mTorr in the growth chamber was used. The electron inelastic mean free path (IMFP) for B"4C and BC"2N was calculated for energies between 200 and 2000eV from their respective energy-loss functions, which was obtained from quantitative analysis of REELS. The IMFPs are analyzed in terms of the Bethe equation for inelastic scattering of electron. REELS results were used to obtain the dielectric function of the B"4C and BC"2N in the energy range from 4 to 100eV.

Due to the Au conductivity, good electric characteristics of AuN are expected, which could generate applications in the electronic industry. AuN films were grown through the Plasma Assisted Physic Vapor Deposition (PAPVD) by the pulsed arc technique. Films were chemically characterized through X-Ray Photoelectron Spectroscopy (XPS) in order to determine its composition. Using Scanning Tunneling Microscopy (STM), and due to the electric conductivity of the films, images and I-V curves were obtained in order to observe the morphology of the films and to obtain the gap value, respectively.

We have studied the stability of a conducting fluid when it is continuously injected or ejected through a pair of parallel porous walls and escapes in both directions along the channel. The flow forms a stagnation point at the center and the effluence is restricted by a magnetic field perpendicular to the walls. A theoretical analysis of the steady state solutions of the MHD equations in the incompressible case is given as a function of three parameters Re, Rm and MA (Re: Reynolds number, Rm: magnetic Reynolds number, MA: Alfvenic Mach number), for some asymptotic limits. In the case of suction, critical values of the parameters are found for which there are bifurcations in the system. Such bifurcations are pitchfork type. In the case of injection, the flux results always stable.

TiN coatings can be obtained in a relatively wide range of compositions around stoichiometry. Changing the stoichiometry around the 1:1 composition broadens the spectrum of colors and can modify the mechanical properties as compared with those of stoichiometric TiN. In this work, we present the deposition of TiN coatings by using a metallic Ti cathode and varying the nitrogen partial pressure in a cathodic arc evaporation reactive process. The composition, crystalline structure, hardness and color of the different samples are characterized, and the effect of deposition pressure is discussed. The hardest coatings were deposited in the interval of deposition pressures between 5 and 20×10−3mbar. From the reflectance spectra in the visible range, a dominant wavelength of 581–582nm is found for all the TiN samples, very close to that of the pure gold reference spectrum (579nm) with purity colors that increase with the deposition pressure from 0.67 to 0.84 and approaches the color purity measured for the pure gold reference (0.91).

We have grown hematite (α–Fe 2 O 3) thin films on stainless steel and (001)-silicon single-crystal substrates by RF magnetron sputtering process in argon atmosphere at substrate temperatures from 400 to 800°C. Conversion Electron Mössbauer (CEM) spectra of the sample grown on stainless steel at 400°C exhibit values for hyperfine parameter characteristic of bulk hematite phase in the weak ferromagnetic state. Also, the relative line intensity ratio suggests that the magnetization vector of the polycrystalline film is aligned preferentially parallel to the surface. The X-ray diffraction (XRD) pattern of the polycrystalline thin film grown on steel substrates also corresponds to α–Fe 2 O 3. The samples were also analyzed by Atomic Force Microscopy (AFM), those grown on stainless steel reveal a morphology consisting of columnar grains with random orientation, given the inhomogeneity of the substrate surface.

Gold is used in electronic industry like electric conductor for products such as computers, mobiles phones, etc; with the drawback that it is one of the most expensive metals in the market. Gold Nitride is a new material, having excellent physics properties like high hardness, high melting point, high electric conductivity, chemical inertia and good thermodynamic stabily among others. At the moment its study is more about electronics, optics, mechanical properties and growth of the films. AuN thin films were produced by the PAPVD (Plasma assisted Physics Vapor Deposition) method, using the pulsed are technique in a mono-vaporizer system. These films were created with an Au target of 99% purity and deposited on stainless steel 304. It was observed that heating the substrate produces small stoichiometric changes in the film, which makes small changes in the diffraction patterns to appear, like widening in the Au orientation, since the composicional gradient is varying according to the substrate temperature. Au 4f and N1s narrow spectra were analyzed using XPS (X-Ray Photoelectron Spectroscopy), in order to observe stoichiometry in the films.