Este trabalho apresenta o desenvolvimento e a valida\c{c}\~{a}o de um algoritmo computacional cuja finalidade é ajustar linhas isoladas de um espectro óptico obtendo os valores para os par\^{a}metros de um perfil Voigt ou Pseudo-Voigt. A recupera\c{c}\~{a}o destes par\^{a}metros é importante para o estudo do espectro de emiss\~{a}o de plasma produzido por laser. Os espectros testados foram bem aproximados pelas fun\c{c}\~{o}es ajustadas e a rotina de ajuste mostrou-se muito promissora para linhas espectrais isoladas. O método é avaliado e testado usando linhas simuladas e aplicado a dados experimentais da linha \textit{H$\alpha$} (656,273 nm) do hidrog\^{e}nio. Os par\^{a}metros do ajuste foram utilizados para determinar a densidade e a temperatura do plasma.

The calcium‑phosphorus ratio (Ca/P) has an important role in calcium phosphate applications, as a slight change in this ratio results in substantial modifications of their characteristics. Hydroxyapatite is a bioactive ceramic of the calcium phosphate family, and its composition and crystalline structure are similar to the human bone. For this reason, it is widely used to promote bone integration in prosthetics and scaffolds. Prosthetics are usually made of metal and coated with bioceramics and the some techniques used to make these coatings depositions conserve the stoichiometry from the target during deposition. Therefore, studying the target Ca/P is a way to guaranteeing the final deposition stoichiometry. In this study, we investigated the One Point Calibration – Laser Induced Breakdown Spectroscopy (OPC-LIBS) method for the measurement of the Ca/P of hydroxyapatite targets. This method is quantitative, based on the determination of correction parameters via analysis of a standard sample with known stoichiometry. Results were compared to well-established techniques of X-ray Fluorescence (XRF) and Atomic Absorption Spectroscopy (AAS) and showed that the deviation in the difference is less than 5%, proposing a substitute for elemental analysis. Moreover, this method has technical advantages such as rapid measurements, no need for sample preparation or destruction and easy automation.

This study aimed to evaluate the consumers' perception (n = 1085) about processing chocolate milk drinks by cold plasma. The consumers were asked about food technology neophobia, familiarity and, willingness to buy the product, sensory attributes, and perceived quality compared to traditional technologies. The consumers considered that new technologies could have a negative impact on health, natural quality of the product, and environment, that the benefits of the new technologies are overstated, and that could be a risk replacing the traditional technologies. However, most of the consumers (72.3%) were willing to buy the chocolate milk drink processed by cold plasma, mainly if the price is similar to that of the conventional product. Chocolate milk drink should have a brown color, chocolate flavor, typical chocolate and milk taste, and high consistency. The willingness to buy the new product increases with the belief that the new technologies would not bring negative health effects, while it decreases with the unfamiliarity with new technologies, doubts about the information provided by the media, or no perceived quality compared to the traditional technology. Therefore, it is important that the food industry provide consumers with trustable, understandable, and clear information so that the lack of confidence could be overcome.

This study aimed to evaluate the effect of the process time (5, 10, and 15 min) and flow rate (10, 20, and 30 mL/min) of cold plasma technology on physio-chemical characteristics (pH), bioactive compounds (DPPD, Total Phenolic Compounds, ACE-inhibitory activity values), fatty acid composition, and volatile compounds profile of chocolate milk drink. The mild (lower flow rate and process time) and more severe (higher flow rate and process time) conditions led to a reduction of the bioactive compounds (total phenolic compounds and ACE-inhibitory activity), changes in fatty acid composition (increased saturated fatty acid and decreased monounsaturated fatty acid and polyunsaturated fatty acid), less favorable health indices (higher atherogenic, thrombogenic and hypercholesterolemic saturated fatty acids and lower desired fatty acids), and lower number of volatile compounds. In contrast, in intermediate cold plasma conditions, an adequate concentration of bioactive compounds, fatty acid composition, and health indices, and increased number of volatile compounds (ketones, esters, and lactones) were observed. Overall, cold plasma technology has proven to be an interesting alternative to chocolate milk drinks, being of paramount importance the study of the cold plasma process parameters.

The present study aimed to evaluate the effect of cold plasma processing parameters (time and flow rate) on the physical (rheological parameters and particle size), microstructure (optical microscopy) and thermal properties (differential scanning calorimetry) of chocolate milk drinks. The beverages treated by cold plasma presented particles with increased size and had higher consistency and altered melting profile (lower temperature and bound water and higher enthalpy) than the pasteurized product, suggesting denaturation processes and formation of protein aggregates. More severe conditions resulted in beverages with particles of larger surface areas ([D 3,2]) and volume diameters ([D4,3]), resulting in higher consistency. Intermediate processing conditions resulted in products with characteristics more similar to the pasteurized beverages. The results indicate that the beverages submitted to cold plasma and pasteurization have different physical characteristics, melting profile and microstructure. Chocolate milk drinks with different characteristics could be obtained varying the cold plasma process parameters.

Background: Thermal pasteurization and sterilization are predominantly used in the dairy industry due to their efficacy in improving the product safety and shelf life. However, heat treatment can cause undesirable protein denaturation, non-enzymatic browning, loss of vitamins and volatile flavor compounds, freezing point depression, and flavour changes. Cold plasma is a non-thermal technology that has gained attention in recent years as a potential alternative method for chemical and thermal disinfection in foods using ambient or moderate temperatures and short treatment times. Scope and approach: This review aims to describe the fundamentals, parameters, and technology on cold plasma, discussing the critical processing factors involved in this technology. Also, it describes the mechanisms of microbial inactivation and provides an overview of the effects of non-thermal plasma on the quality of dairy products, considering a physicochemical, sensory and microbiology perspective. Key findings and conclusions: Cold plasma uses less aggressive mechanisms of action to the milk matrix when compared to the techniques currently used, and has shown an excellent performance on the elimination of pathogenic and spoilage microorganisms besides maintaining, in many cases, the nutritional, functional, and sensory characteristics of the product.

The effect of cold plasma processing time and gas flow on bioactive compounds such as vitamin C, carotenoids and phenolic compounds, DPPH, angiotensin-converting-enzyme (ACE) inhibitory activity, fatty acids profile, and volatile compounds of guava-flavored whey beverage was investigated. For comparative purposes, a pasteurized beverage was also manufactured. Cold plasma increased the concentration of bioactive and volatile compounds, and proportionated changes in the fatty acids profile. The milder conditions like lower flow rate and processing time, resulted in higher vitamin C and volatile compounds levels, and higher antioxidant activity, but with a lower carotenoids content and a less favorable fatty acids profile. More drastic conditions like higher flow rate and processing time resulted in products with lower vitamin C and volatile compounds levels, but with higher carotenoids content and ACE inhibitory activity. It can be concluded that the cold plasma processing can improve the properties of the guava-flavored whey beverages (increased concentration of bioactive and volatile compounds), while the effect on the fatty acid profile and ACE inhibitory activity is dependent on the process parameters (processing time and flow rate).

Mercury is a chemical element used in multiple applications; it is non-degradable and has bioaccumulation potential. Among toxic metals, mercury gets attention for its high toxic capacity. There is, therefore, great interest in developing analytical techniques for detection and real-time monitoring of mercury, to obtain reliable data for fundamental and applied studies, aimed to a rational and responsible use of this material, and to minimize its impact on the environment. In this work, the Laser-Induced Breakdown Spectroscopy (LIES) technique is applied to the analysis of dental amalgams with varying mercury concentrations in an Ag-Cu-Sn matrix. For each multi-elemental sample, we observed and recorded the spectra of laser-plasmas at delay times after the laser pulse between 1 and 5 mu s. Calibration curves were built to determine the concentration of mercury in the amalgams, using suitable corrections to compensate for the changes in electron number density and temperature associated to the large changes in the samples' matrix occurring at the different Hg concentration. The accuracy of the calibration curves at different delay times was estimated and discussed.

An innovative CF-LIBS procedure based on self-absorption corrections applied to a quantitative analysis of a doped frozen aqueous sample.

The present study aimed to compare the physicochemical (pH), physical (rheology parameters and particle size), microstructure (optical microscopy) and thermal properties (differential scanning calorimetry) of guava flavored whey-beverages submitted to cold plama technology in different processing time (5, 10, and 15 min) and gas flow (10, 20, and 30 mL min-1) conditions with a conventional pasteurized product. Whey beverages treated by cold plasma presented higher pH values, lower consistency and lower viscosity, and a flow behavior index similar to Newtonian fluids. Milder cold plasma conditions resulted in whey beverages with higher pH, lower viscosity and consistency, and similar particle distribution and microstructure compared to the pasteurized product. In contrast, more severe processing conditions resulted in a higher particle surface area ([D 3,2]) and smaller particles (~10 μM), due to the decrease in the number of larger particles (1000 μM), cell rupture, the formation of cell fragments, and higher viscosity and consistency. The treatments did not affect the thermal properties (enthalpy and bound water) of any sample.

Nd:YAG (532nm) pulsed laser deposition (PLD) has been used to produce crystalline hydroxyapatite (HAP) coatings at room temperature onto silicon substrates. The PLD HAP coatings were homogeneous (100.4nm RMS roughness) and consisted of micrometric particles (>10μm) coalesced over a nanometric dense layer. The deposition parameters of 532nm laser, 30J/cm2 fluence, 10−4Pa vacuum environment and room temperature are capable of coating any surface with crystalline HAP without requiring heat treatment. It was confirmed by Synchrotron Radiation Grazing Angle X-ray Diffraction (GAXRD) patterns that the nanocrystalline component present in the coatings was reduced and did not hide peaks of decomposition to other calcium phosphate (CaP) phases when in situ heat treatments of 200°C and 800°C were performed. The use of dense and stoichiometric HAP targets that could withstand the high-fluence laser allowed producing 150nm crystalline HAP coatings in only 5min of deposition time, although 532nm laser wavelength is outside the absorption range of the HAP. This contribution opens the perspective to produce controlled PLD HAP coating over thermally sensitive substrates with reduced processing time for large-scale production for biomedical applications. As a demonstration, HAP coating was deposited and characterized on thermal sensitive bioabsorbable polylactide (PLA) surfaces.

The non-equilibrium electro-thermodynamic properties of magnetized plasma produced by a modified radio-frequency magnetron sputtering system were investigated in detail. The plasma was analyzed using Hall, Langmuir, and Faraday probes and optical emission spectroscopy, and numerical simulations were conducted to determine the electric and magnetic field profiles. It is found that the occurrence of lower hybrid resonance and excitation of helicon waves are satisfied locally along the plasma profile (Z). This unusual effect in magnetron sputtering systems plays an important role in the increase of the electrons and ions temperature improving the quality of the films produced. Films of complex structure as hydroxyapatite that have biomedical applications were produced along the Z to confirm our plasma results. The films were characterized by performing grazing incidence X-ray diffraction using synchrotron radiation, X-ray photoelectron spectroscopy and atomic force microscopy. The microstructure analysis of hydroxyapatite films produced at different Z revealed that films with high crystallinities and with ideal stoichiometries (Ca/P = 1.67 +/- 0.05) were produced within a magnetic cusp region (26 mm < Z < 32 mm). Based upon the results from plasma diagnostics and films characterization, we proposed a model of plasma of this system. The delivered energy by ions bombardment for films formation was determined and reached values around 8 eVs(-1)A(-2) and plasma temperature of T approximate to 10 eV inside the magnetic cusp region. Finally, this work opens the possibility to produce coatings of other complex compounds by the fine-tuning of resonant waves and their high delivered energies in vacuum magnetized plasmas. (C) 2017 Elsevier Ltd. All rights reserved.

Recent results of experimental work and theoretical modeling carried out in the TCABR tokamak are reported on characterization of MHD instabilities, improved diagnostics of rotation of the plasma column, excitation of Alven global modes, identification of GAMs, and the effect of rotation on their behavior. Detailed measurements of edge electrostatic perturbations and of magnetic island evolution and rotation indicate that the edge turbulence is substantially affected by the islands growth, leading to a strong modulation of the edge particle losses at the same frequency of the MHD activity. Measurements with spatial resolution also show that the growth of the MHD activity is due to nonlinear coupling of magnetic islands with different poloidal mode numbers, which increases the impurity influx. A new system of data acquisition and processing of the TCABR plasma rotation diagnostic was implemented. The system is based upon a single monochromator coupled with six photomultipliers tubes and allows one toroidal and two poloidal simultaneous rotation measurements. The excitation of Global Alfven Waves - GAW has been investigated, using a new type of radio frequency amplifier. The GAW resonances are searched either by a pre-programmed density variation, at fixed generator frequency, or through three RF frequency sweeps from 2 to 4.5 MHz, at stationary density. GAW resonances have been found and their somewhat new characteristics are presented. The investigation of the effect of poloidal and toroidal rotation on the characteristics of the geodesic acoustic mode has been investigated, both theoretically and experimentally. It is found that the assumption of isothermal flux surfaces gives rise to a third branch of this mode. Detailed predictions coupled with experimental measurements are currently being carried out to investigate this question.

A fast and precise method for the determination of electron temperature and electron number density in laser-induced plasmas is presented. The method is based on the use of a simple artificial neural network (ANN), trained on a suitable set of laser-induced breakdown spectroscopy spectra. The training procedure is quite fast; once the ANN is set, the determination of plasma temperature and electron number density is almost instantaneous, allowing the possibility of measuring these parameters, with good precision, in real time. A direct application of this new method could be the characterization of plasmas generated during pulsed laser deposition process of thin films and nanoparticles generation. The plasma electronic parameters will help to tune the energies involved in the stoichiometry and crystallization control of those nanostructured materials. As an example, the characteristics of the plasma induced by a Nd:YAG laser on a pure titanium target are determined, at different laser fluences.

This work presents the experimental analysis of the central electron temperature measured by the electron cyclotron emission (ECE) radiometer and the infrared Thomson Scattering (ITS) diagnostic. The detection of the ECE radiation is done by a heterodyne scanning radiometer that works at the second harmonic extraordinary mode, in frequency range from 50 to 85GHz, which allows measurement of the radial profile of electron temperature with good spatial and temporal resolutions. The ITS diagnostic uses a Neodymium Glass laser (wavelength 1.054 μm). This ITS diagnostic measures the electron temperature in the center of plasma column one time during plasma shot. Results also show a discrepancy between the two diagnostics in the electron temperature measurement in the presence of Magnetohydrodynamics activity that gives an explanation for this apparent inconsistency.

We present a method to estimate the temperature of transient plasmas and their degree of departure from local thermodynamic equilibrium conditions. Our method is based on application of the Saha–Boltzmann equations on the temporal variation of the intensity of the spectral lines of the plasma, under the assumption that the plasmas at the different times when the spectra were obtained are in local thermodynamic equilibrium. The method requires no knowledge of the spectral efficiency of the spectrometer/detector, transition probabilities of the considered lines, or degeneracies of the upper and lower levels. Provided that the conditions of optically thin, homogeneous plasma in local thermodynamic equilibrium are satisfied, the accuracy of the procedure is limited only by the precision with which the line intensities and densities can be determined at two different temperatures. The procedure generates an equation describing the temporal evolution of the electron number density of transient plasmas under local thermodynamic equilibrium conditions. The method is applied to the analysis of two laser-induced breakdown spectra of cadmium at different temperatures.

Fil: Bredice, Fausto Osvaldo. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - la Plata. Centro de Invest.opticas (i); Argentina;

Long-distance correlations (LDCs) of plasma potential fluctuations in the plasma edge have been investigated in the TCABR tokamak in the regime of edge biasing H-mode using an array of multi-pin Langmuir probes. This activity was carried out as part of the scientific programme of the 4th IAEA Joint Experiment (2009). The experimental data confirm the effect of amplification of LDCs in potential fluctuations during biasing recently observed in stellarators and tokamaks. For long toroidal distances between probes, the cross-spectrum is concentrated at low frequencies f < 60 kHz with peaks at f < 5 kHz, f = 13-15 kHz and f similar to 40 kHz and low wave numbers with a maximum at k = 0. The effects of MHD activity on the LDCs in potential fluctuation are investigated.

An analytical method is proposed to evaluate the experimental uncertainty in the electron temperature measurements in the TCABR tokamak. Solving the integral equation resulting from the convolution of two functions, one representing, the scattered light and the other the spectral apparatus function, i.e., the polychromator, an analytical expression for the electron temperature is obtained, from which the uncertainty in the measured value is readily evaluated. The results show that the major contribution to the error comes from the noise in the signal; the uncertainties in the filters parameters do not contribute significantly to the total error.