Isotopic and Elemental Authenticity Markers: a Case Study on Cypriot Wines

This study monitors variations in isotopes and elements in relation to grape variety, environmental factors and provenance in order to address the wine authenticity issue. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) assessed the wines’ elemental content. Site-specific nuclear isotope fractionation-nuclear magnetic resonance and isotope ratio mass spectrometry methodologies determined in authentic and commercial wines the distribution of the naturally occurring stable isotopes of the deuterium/hydrogen (D/H) ratios and carbon (¹³C/¹²C) in ethanol of wine and oxygen ratio (¹⁸O/¹⁶O) in wine water. Chemometrics delineated the elements and isotopes responsible for wine classification. Specifically, unsupervised principal component analysis (PCA) framed the importance of grape variety and provenance, while supervised analysis pinpointed the vineyard effect and highlighted the contribution of the vintage year. Validation steps ensured that the extracted models do not predict randomly and their results are reliable. In fact, the acquired results can be incorporated to the EU Wine Isotopic Databank database providing both a guide and a tool for eventual candidatures for denomination of origin and support both Cypriot wine and winemakers. In this context, this research contributes to authenticity assurance of wines and adds value to final products, while it helps controlling hazards arising from environmental changes.     

Development of NiO-based thin film structures as efficient H2 gas sensors operating at room temperatures

P-type NiO thin films have been developed on high resistivity Si and SiO₂ substrates by a pulsed laser deposition technique using an ArF^? 193 nm excimer laser at deposition temperature of 300 °C and in 40 Pa partial oxygen pressure. Structures based on such NiO films as host material in the form of Au-NiO Schottky diodes have been subsequently developed under vacuum. In a different procedure, an n-SnO₂ layer has been deposited by a CVD technique on a NiO film to produce a p/n heterojunction. The sensing properties of all above structures have been tested upon exposure to a H₂ flow in air ambient gas at various operating temperature ranging from 30 to 180 °C. For the NiO films, the optimum temperature was about 150 °C exhibiting a sensitivity of 94%. After surface sensitization of NiO by Au the NiO films showed an H₂ response at operating temperature of 30 °C. The sensitivity of p-NiO/n-SnO₂ heterojunction devices was extracted from I-V measurements in air and under H₂ flow mixed in air. In this case a dramatic increase of the sensitivity was achieved at operating temperature of 30 °C for a forward bias of 0,2 V.     

Fully Stratified Particle-Laden Flow in Horizontal Circular Pipe

This article describes the results of an experimental measurement and visualization of coarse-grained fully stratified particle-water mixtures. This article focuses on the study of the carrier liquid velocity field and behavior and local velocities of conveyed particles. Glass balls and graded pebble gravel of 6 mm mean diameter were conveyed by water in a horizontal smooth pipe loop with a transparent pipe viewing section of inner diameter 40 mm. The measurements were performed in the smooth pipe and the pipe with rough stationary bed created by two layers of spherical particles of the same mean diameter as the conveyed particles. Particle movement along the pipe bottom was studied and the effect of the stationary bed on local velocity values of the carrier liquid and conveyed particles were evaluated. It was concluded that in the flow with stationary bed the maximum liquid velocity is markedly shifted from the pipe center to its top. The coarse-grained particles moved principally in a layer close to the pipe invert, for higher flow velocities particle saltation becomes the dominant mode of transport.     

RF sputtered indium-tin-oxide as antireflective coating for GaAs solar cells

Conductive and antireflective indium-tin-oxide (ITO) has been prepared by RF sputtering in Ar atmosphere, without introducing oxygen into the plasma and on room temperature substrates in order to be used as antireflective coating on GaAs solar cells. The electrical resistivity of the n-type, degenerate ITO films exhibited a reduction with deposition rate and an increase with total pressure, while it was independent of the film thickness in the range of 20 nm to 130 run. Further reduction of resistivity, up to 4 × 10⁻⁴ Ωcm, was obtained by annealing at 400°C. This is the lowest resistivity that has been reported for TTO films prepared under similar conditions. The transmittance of 90 nm thick ITO film was 85% and the reflectance of p/n GaAs solar cell was reduced from 35% to 2% after the ITO layer application.     

Road to Next Generation Mobile Networks: An Evolutionary Dynamics Approach

One of the major challenges that mobile operators (MOs) are faced with nowadays is the transition to 4th Generation (4G) mobile communication technologies. The main reason for this lies on the reluctance of MOs to invest in a new technology without being sure about its success. The current paper investigates the decision-making procedures of a MO that wishes to migrate from its current technology type to 4G. Traditionally, the decision of deploying a new technology has been based on the analysis of similar implementations in other countries. However, such approaches can be inefficient and time consuming, as there are discrepancies concerning the technological progress among different countries. To this end, the authors employ evolutionary game theory to model the interactions of the MO’s decisions and the subscribers’ needs, and propose a practical and efficient qualitative model that identifies the circumstances under which the transition towards 4G networking can be facilitated. Specifically, the mathematical foundation of the decision making process is provided and the key role of the charging price and the quality of experience by the subscribers for using 4G connectivity is proven. With the process of 4G deployment still ongoing, this paper aims to present an analysis that can be used supplementary to the decision process of a MO that aims to evolve his network.     

Determination of Antibiotic Residues in Honey by High-Performance Liquid Chromatography with Electronspray Ionization Tandem Mass Spectrometry

The aim of the present study was to develop a rapid and simple method for the detection and quantification of antibiotic and antibacterial residues in honey using liquid chromatography with electronspray ionization tandem mass spectrometry. Two different extraction methods were used. The first method uses water and 1% formic acid in acetonitrile for the determination of sulfonamides while the second uses phosphate buffer, 10% trichloroacetic acid, and acetonitrile as the extracting solvent for the determination of tetracyclines, amphenicols, fluoroquinolones, penicillin g, trimethoprim, and tiamulin. The multi-residue method was validated in a thyme honey matrix. Thirty-six different antibiotics and residues from four different families (sulfonamides, tetracyclines, amphenicols, fluoroquinolones) and some individual antibiotics (penicillin g, trimethoprim, and tiamulin) were tested in 20 honey samples originating from Cyprus and Greece. The decision limits (CCα) were from 0.1 to 9.2 μg kg^?1; the detection capabilities (CCβ) were from 0.3 to 27.6 μg kg^?1 while recoveries were from to be between 65.0 and 116.1%. The method was successfully applied to commercial samples from different types of honey from Greece and Cyprus. Among them, oxolonic acid, sulfathiazole, and sulfadimethoxine were found in three honey samples. Finally, proficiency testing was applied to the proposed method while analysis of certified samples showed good method performance characteristics.     

First Stages of Internal Oxidation in Ag-0.29 and 2.89 at. % Mg Single-Crystal Alloys

Internal oxidation of Ag-0.29 and 2.89 at.% Mg alloys was studied by in-situ X-ray measurements at 300°C. The kinetics and lattice-parameter changes as a function of time are discussed in terms of the formation of elementary MgO* species and non-stoichiometric clusters, during the first stages of oxidation. Studies were made using synchrotron radiation on single-crystal samples. The distorted zone, formed near the surface, was detected by measuring the position and the intensity of the (022) silver peak in the solid-solution alloy. From the diffraction-peak changes, information is deduced on the growth kinetics of the expanded layer. Oxygen diffusivity in silver, C ₀ D ₀, is calculated on the basis of Wagner’s law. At an early stage, the oxygen diffusivity is slightly lower than the theoretical value. During a second stage, accelerated kinetics give a very high C ₀ D ₀ value. We determined the O/Mg ratios at different stages during oxidation.     

Studies on the Authenticity of Local Wines by Spectroscopic and Chemometric Analysis

The authenticity of 91 wines produced in Cyprus from both indigenous and other vine varieties were investigated by a holistic approach, using, advanced technology such as SNIF-NMR （site-specific natural isotopic fractionation-nuclear magnetic resonance） and 1R-MS （isotope ratio-mass spectrometry） for the determination of the stable isotopes and ICP （inductively coupled plasma spectroscopy） for some heavy metals. The spectroscopic characteristics were evaluated statistically using different chemometric methods. The dependency of the D/H （deuterium/hydrogen） ratio of the methylene site in the ethanol molecule （D/H）ll and also theδ ^18O values of the wine water, were the most useful discriminators. Isotopic results allow us to have a complete idea about the regional variability of the isotopes. Among the metals, Ni followed by Pb was the ones with the highest discrimination value. The determined concentrations of Pb, Ni, Cr and Cd that are related to the safety of wines were within the acceptable limits that have been established by the OIV （international organization of vine and wine） or comparable with the results of the wines of other European countries. The study of the correlation between the load of heavy metals and isotopes in wines showed a dependence on the grape variety but not the geographical location of the vineyard. This is probably due to the close proximity of wine regions in Cyprus.     

The effects of thermomechanical processing on the precipitation in an industrial dual-phase steel microalloyed with titanium

Analytical transmission electron microscopy was employed to characterize the precipitation at each step of the fabrication process and thermomechanical treatment of an industrial dual-phase steel microalloyed with titanium. Theoretical thermodynamic calculations as well as experimental analysis showed that more than half of the titanium carbosulfide (Ti₄C₂S₂) precipitates would dissolve during reheating at 1240 °C. Despite this dissolution at 1240 °C, the remaining titanium carbonitrides and carbosulfides were effective in pinning austenitic grain boundaries, keeping the austenitic grain size at around 40 μm (at 1240 °C). It is also shown that, during hot rolling, there exist three regions of titanium carbide precipitation. The first is defined by an increase of titanium carbide precipitation due to deformation. The second region is marked by the insignificant change in precipitation. The third region is indicated by another increase in precipitation due to the austenite-to-ferrite transformation. The experimental and theoretical results on the contribution of TiC precipitation to hardening of ferrite (Orowan mechanism) were in excellent agreement, showing that TiC precipitates have the most important effect on increasing the yield strength, overshadowing the austenitic grain-boundary pinning contributions by Ti(C,N) and Ti₄C₂S₂ precipitates.