High-resolution H-1 NMR, high-field H-1 NMR relaxometry, and low-field (<0.5 T) NMR relaxometry have been applied to study different types of olive and soybean oils. It has been shown that the use of spectral and relaxation information in high-field NMR is an effective tool for the detection of oil adulteration and identification of food oils, including oils with close content. We have also shown that low-field NMR relaxation measurements can be applied for the discrimination between various food oils in the case of a limited group of samples. This work has demonstrated the possibilities of the different types of pulse NMR experimental methods for the analysis of vegetable oils.

In this work, we describe the experiments for the detection of ammonium nitrate (AN) with a toroidal RF probe with an effective detection volume of 137.5 L. The system includes a Tecmag Scout NQR console, a Tomco linear power amplifier (4 kW), a duplexer and a high-power Q-factor spoiler. We studied the influence of partial metal shielding with an aluminium foil as well as the inclusion of metal pieces in an AN sample on the detection of the AN NQR signal. We have also tested NQR detection of AN placed in the open box made of soft iron plates. We have shown that the detection of the NQR signal of AN in the configurations where there is a hole in the shield around the AN sample is possible.

Over the last few decades, the utilization of microwave (MW) spectroscopy applications in industry has grown dramatically. This technique is very useful as it gives very important details about alcohol-water mixtures through the measurement of dielectric parameters (Ɛ’ and Ɛ”). This research determined the dielectric parameters (Ɛ’ and Ɛ”) of ethanol-water and methanol-water mixtures for concentration changes from pure water to pure alcohol. The ethanol-water and methanol-water mixture volume fractions of 43% and 44%, respectively, as well as the molar fractions xet≈ 0.20M and xmet ≈ 0.26M, obtained the breaking points of the dielectric parameters (Ɛ’ and Ɛ”).

Increasing worldwide food demand as a result of the increasing population has led to an increase in vegetable oil prices. Olive oil, one of the most popular edible oils, is regrettably commonly adulterated by the addition of a different, less expensive oil to lower its price. As a result, many processes are carried out on edible and olive oil is one of the most cheated products today. Microwave dielectric technique (MW), in parallel with Time Domain Nuclear Magnetic Resonance (TD-NMR) technique, has started to be used in food analysis because it can analyze the content of the product, which cannot be distinguished by sensory characteristics in a simple, fast and high-efficiency way.In this study, spin–lattice (T 1 ) and spin–spin (T 2 ) relaxation times of edible oils were measured. Dielectric permittivity constants Ɛ 1 and Ɛ 2 have also been measured from 10 MHz to 20 GHz. It is observed that spin–spin (T 2 ) and spin–lattice (T 1 ) relaxation times of pure olive oil are shorter than those of sunflower oil and that T 1 and T 2 are shorter for riviera olive oils than for extra virgin olive oils. It was found that the T 1 and T 2 values increased with the increase in temperature in the measurements based on the investigation of the impact of temperature on the relaxation times. The highest Ɛ 1 values are found in sunflower oils, while the lowest Ɛ 1 values are found in riviera olive oil. As is well known, the amounts of oleic and linoleic acid in edible oils also affect the T 1 -T 2 , viscosity, and Ɛ 1 -Ɛ 2 values. As a result, relaxation times and dielectric parameter constants are used to categorize and distinguish edible oils, particularly extra virgin and riviera olive oils.

The analysis of edible oils, which have an important place in human health, is very significant. One of the most widely used edible oil is olive oil, which unfortunately is very frequently adulterated by adding a different, cheaper oil to reduce its cost. Therefore, a useful and economical method or device is needed to detect counterfeiting and adulteration of oils. In this study, a low-cost, easy-to-use, lightweight, and practical time-domain nuclear magnetic resonance (TD-NMR) device was developed for quality control and food safety applications, including testing edible oils. For this purpose, a measurement system, consisting of an O-shaped magnet with NdFeB permanent disc magnets, a radio frequency (RF) detection probe and a temperature stabilization/control system, was designed. Using this homemade device, the spin–lattice ( T 1 ) and spin–spin ( T 2 ) relaxation times of seven different olive oils were measured. The received results were compared with those obtained by two different commercial low-field NMR (LF-NMR) devices. It was established a good agreement between the experimental results obtained on the homemade system and the commercial LF-NMR devices. Detection of various grades of olive oil, as well as oil adulteration, was demonstrated for a set of different olive oils and a mixture of olive and sunflower oils using the developed homemade TD-NMR device.

In this work, we describe the design of a sensing system for the NQR detection of nitrogen substances in a large inspection volume. The system consists of a Tecmag Scout NQR console, Tomco linear amplifier (4kW), a large distance/volume RF probe (either planar gradiometer or toroidal coil), a duplexer and a high-power Q-factor spoiler. We studied the conditions for optimal unilateral detection at distances up to 20 cm as well as for the detection inside a large volume. It has been shown that depending on RF probe configuration and ambient RF noise level), a $14_\mathrm{N}$ NQR signal of a small amount (100 g) of hexamethylenetetramine (HMT) as the reference nitrogen substance can be detected using both types of RF detectors. Furthermore, a possibility of NQR detection for a partially shielded HMT sample has been also shown. The influence of conducting bodies near an NQR sample for detection performance has been studied as well. We have also demonstrated that this system can be applied to the detection of ammonium nitrate.

Single crystal (100) and (001) TiO2 rutile plates were implanted with vanadium 40 keV ions to the fluence of 1.5 x 10(17) ion cm(-2). A set of samples was also annealed at high-temperature in air to restore oxygen stoichiometric content and recover the TiO2 lattice structure after the high-dose ion implantation. In addition, a control set of TiO2 rutile plates was implanted with 40 keV argon ions to the same fluence to explore the effect of radiation-induced defects on magnetic properties. Rutherford backscattering spectroscopy (RBS), x-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM) measurements were carried out to characterize the structural and magnetic properties of the vanadium-implanted TiO2. Both as-implanted and subsequently annealed V-TiO2 samples reveal ferromagnetic response at room temperature. Strong ferromagnetism observed in the vanadium-implanted (001) TiO2 plates is related to the \substitutional V4+ ions coupled by the indirect exchange via electrons trapped at oxygen vacancies, while much weaker ferromagnetism in the (100)oriented plates and the Ar-implanted samples is attributed to lattice defects induced by the high-dose ion irradiation. Suppression of the ferromagnetic response in the vanadium-implanted (001) TiO2 after the thermal treatment is explained by filling in the oxygen vacancies due to oxygen diffusion during annealing in air atmosphere.

In the current study, ABO3 (A = Pb, Ba, Sr and B = Ti) perovskite structures are produced by the auto-combustion route by using citric acid (CA) and nitric acid (NA) as fuel and oxidizer. The X-ray diffraction (XRD) patterns confirmed the perovskite nanostructure with cubic, tetragonal, and rhombohedral for SrTiO3, PbTiO3, and BaTiO3, respectively. Using Scherrer’s equation and XRD pattern, the average crystallite size of the samples were acquired. The effect of Ti–O bond length on the structure of the samples was evaluated. The type of structures obtained depends on Ti–O bond length which is in turn influenced by A[Formula: see text] substitutions. Microstructural studies of nanostructures calcined at 850[Formula: see text]C confirmed the formation of polyhedral particles with a narrow size distribution. The values of optical band gaps were measured and the impact of A[Formula: see text] was discussed. The optical properties such as the complex refractive index and dielectric function were calculated by IR spectroscopy and Kramers–Kronig (K–K) relations. Lead, as the element with the highest density as compared to other elements, changes the optical constants, remarkably due to altering titanium and oxygen distance in TO6 groups.

Recently tetrahedrite compounds have attracted great attention due to their potential applications on the mid temperature thermoelectric technologies. In this work, structural, Electron Paramagnetic Resonance (EPR) and the thermoelectric properties of tetrahedrite (Cu12-xFexSb4Si13 where x = 0.0, 1.0, 1.5, 2.5) were investigated. The crystal structural, morphological properties and elemental compositions of the samples were investigated by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS-EDX) tools respectively. Magnetic properties of the samples were performed by EPR techniques using electron spin resonance (ESR) spectrometer with the model of Bruker EMX series at X-band (9.5 GHz). The thermoelectric properties were assisted based on Seebeck coefficient, electrical resistivity, and thermal conductivity measurement between 300 and 600 K temperature range. PXRD patterns and SEM-EDX analysis confirmed the main phase of tetrahedrite structure for all compounds. The Seebeck coefficient sign indicated that holes were dominant carriers in all compounds. Electrical resistivity measurement showed an increment with increasing Fe concentration likely due to decreasing in carrier density. A typical behavior of intrinsic semiconductor was observed from temperature-dependent electrical resistivity measurements. The maximum ZT value of 0.6 was achieved for the sample Cu11Sb4S13 at 550 K. Electron Paramagnetic Resonance (EPR) and thermoelectric measurements exhibited that the maximum Fe concentration might be 5 1.0 for achieving high ZT value in Cu12-xFexSb4Si13 compounds.

Magnetic cobalt-gold thin films (Co Au(1_)) are grown on silicon (100) surfaces by using a sputter deposition technique. Magnetic anisotropy of the films is investigated by ferromagnetic resonance (FMR). Magnetic properties are explored by micromagnetic simulations based on the metropolis algorithm. Effective magnetic anisotropy is gradually increased with Co concentration. In-plane axial anisotropy exists for all samples and it is enhanced with a Co concentration of similar to 40% corresponding optimal cluster size, and intercluster separation. Segregation and coalescence of Co clusters caused by different Co concentrations strongly affect magnetic properties of the thin films. Therefore, the study revealed that magnetic behavior of Co Au(1-x) thin films can be tuned by changing Co concentration.

Birçok sülfat tuzu mineralleri arasında, tetrahedrit/tennantit grubu, termoelektrik ve fotovoltaik gibi ileri teknoloji uygulamalarında umut verici bir yere sahip olduğundan dolayı araştırmacıların ilgisini çekmektedir. Bu çalışmada katıhal reaksiyon metodu hazırlanmış ve ayrı ayrı vakumlu kuartz tüplere kapatılmış (Cu12Sb4S13) tetrahedrit ana malzemesi, %50Sb %50As tetrahedrit/tennantit bileşiği (Cu12As2Sb2S13) ve Cu12Sb4S13 ana malzemesindeki Cu elementi yerine kısmi olarak Fe katkılanan bileşiğinin (Cu10Fe2Sb4S13) yapısal karakteristikleri X-ışını kırımı tekniği (XRD) analiz edilmiştir. Oluşan bileşiklerin morfolojileri taramalı elektron mikroskobu (SEM) ile görüntülenmiş ve buna bağlı enerji dağıtıcı X-ışını spektrometresi (EDX) ile oluşan kompozisyonun element oranlarının analizleri yapılmıştır. Bu bileşiklerin ayrıca manyetik özellikleri, titreşimli örnek manyetik ölçüm tekniği (VSM) ile incelenerek belirlenmiştir. Tüm örnekler paramanyetik özellik göstermekte olup manyetik moment eğrilerinde Curie yasası ile uyumlu davranış gözlemlenmiştir.

Single-crystal (100) and (001) TiO2 rutile substrates have been implanted with 40 keV Fe+ at room temperature with high doses in the range of (0.5–1.5) × 1017 ions/cm2. A ferromagnetic resonance (FMR) signal has been observed for all samples with the intensity and the out-of-plane anisotropy increasing with the implantation dose. The FMR signal has been related to the formation of a percolated metal layer consisting of close-packed iron nanoparticles in the implanted region of TiO2 substrate. Electron spin resonance (ESR) signal of paramagnetic Fe3+ ions substituting Ti4+ positions in the TiO2 rutile structure has been also observed. The dependences of FMR resonance fields on the DC magnetic field orientation reveal a strong in-plane anisotropy for both (100) and (001) substrate planes. An origin of the in-plane anisotropy of FMR signal is attributed to the textured growth of the iron nanoparticles. As result of the nanoparticle growth aligned with respect to the structure of the rutile host, the in-plane magnetic anisotropy of the samples reflects the symmetry of the crystal structure of the TiO2 substrates. Crystallographic directions of the preferential growth of iron nanoparticles have been determined by computer modeling of anisotropic ESR signal of substitutional Fe3+ ions.

Single-crystalline ZnO thin films have been grown on sapphire substrates and implanted by 40 keV Ni+ ions with a dose of 0.25–1.25×1017 ions/cm2. After implantation the samples have been annealed at T=1000°C for 30 minutes in air. Both as-prepared and annealed nickel-implanted ZnO samples have been investigated by ferromagnetic resonance (FMR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and optical techniques. SEM studies reveal that the surface of non-implanted ZnO thin film is very smooth, while microcracks are present in the Ni-implanted ZnO samples. Annealing after implantation recovers the surface of the implanted ZnO. Energy dispersive X-ray spectroscopy shows that the Ni concentration increases with increasing the implantation dose. Optical measurements of the Ni-implanted ZnO thin films indicate that annealing results in formation of a new phase. This phase is attributed to NiO that appears due to redistribution and oxidation of the implanted Ni ions in the ZnO matrix. Magnetic measurements show that both as-implanted and annealed samples exhibit room-temperature ferromagnetism. VSM data indicate that annealing procedure results in decreasing the magnetic moment per Ni atom and higher coercivity at low temperatures. Magnetic-resonance studies reveal highly anisotropic FMR signal in the as-implanted Ni:ZnO samples starting from the dose of 0.5×1017 ions/cm2. We also observe a step-wise increase of the effective magnetization at the dose of 1.0×1017 ions/cm2, which is explained by magnetic percolation of the Ni nanoparticles. Narrow resonance signals with unusual angular dependence are observed in magnetic-resonance studies of the annealed Ni:ZnO samples, which have been related to the formation of a system of non-percolated NiO-coated Ni nanoparticles as a result of annealing in air. We did not observe experimental evidence for intrinsic ferromagnetism in the Ni-implanted ZnO thin films.

Polyethylene terephthalate (PET) foils were implanted with 40 keV Fe+ ions to doses of (0.15–1.50) × 1017 ions/cm2 at ion current density of 4 µA/cm2. The iron‐implanted PET composites were investigated using ferromagnetic resonance (FMR) technique supplemented by transmission electron microscopy (TEM), atomic force microscopy (AFM) and DC resistance measurements. TEM studies revealed formation of iron nanoparticles with size in the range of 5–100 nm depending on the implantation dose. AFM images showed depending on the implantation dose either small bumps or worm‐like structures on the polymer surface that corresponded to the inclusions towered above the surface. The results of AFM studies were found to be in good agreement with the TEM measurements. FMR signal was observed for the foils implanted with the dose higher than 0.15 × 1017 ions/cm2. The effective magnetization of the metal‐polymer composite was extracted from the angular dependencies of FMR resonance field. The percolation transition at the implantation dose of 1.0 × 1017 ions/cm2 was observed in the dose dependencies of the FMR absorption intensity and the effective magnetisation. The minimum in DC resistance found at the same dose indicates that a charge carrier mediated (exchange) interaction rather than the dipolar one is underlying mechanism for the percolation transition. Formation of a carbonized layer in the heavily implanted area of the polymer is supposed to be responsible for the exchange coupling of the magnetic granules. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Different polymers (viscous-flow epoxies, viscoelastic silicone resins and solid state polyimides) were implanted with 40 keV Fe+ or Co+ ions to the doses of 0.1÷2.0×1017 ions/cm2. The influence of the dose and viscosity of polymer target on the process of nucleation and growth of metal nanoparticles in the implanted polymers as well as on the magnetic properties of ion-synthesized composites were investigated by electron microscopy and magnetic resonance. The implantation of the polymers with 40 keV ions causes a surface carbonization of polymer substrate and at the doses more than 0.25×1017 ions/cm2 results in the formation of metal (iron or cobalt) nanophase in thin subsurface layer. Mean sizes, crystalline structure, shape and space packing of the ion-synthesized nanoparticles strongly depend on the dose, kind of implanted ions and the polymer viscosity during implantation. The ion synthesis of the isolated cubic or spherical particles with the mean sizes in the range of 2÷200 nm, as well the formation of many-particles clusters, fractal-type agglomerates and single microscaled plates are observed in the implanted polymers under study. Ion-synthesized iron or cobalt nanoparticles reveal the magnetic resonance response, and at high doses their resonance signals demonstrate the typical features of ferromagnetic resonance in granular magnetic films. The values of magnetization and coercivity of the granular composite films were obtained from the analysis of FMR data. The non-linear dependencies of the composite magnetization on ion dose and on the viscosity of polymer target are presented and discussed in the frame of the magnetic percolation transition in the many-particles system.

Co+ ions of 40keV were implanted in thin polyimide foils with doses in the range of (0.25–1.50)×1017ions/cm2 at ion current densities of 4, 8 and 12μA/cm2. The cobalt-implanted polymer foils were annealed at a temperature of 300°C for 2h in vacuum. Both the as-implanted and post-annealed samples were investigated by the ferromagnetic resonance (FMR) technique supplemented by transmission electron microscopy (TEM). TEM investigations showed that the implantation results in the formation of cobalt granules in the irradiated polymer layer with the thickness of about 70nm. The mean lateral size of cobalt granules varied within 5–20nm depending on the dose. The annealing of the implanted samples induced coalescence of the cobalt granules and increase of their lateral sizes. No FMR signals were found for the as-prepared polymer foils implanted by cobalt ions at low current density of 4μA/cm2. FMR signals were observed for the as-prepared samples implanted at higher ion current densities of 8 and 12μA/cm2 as well as for all annealed samples. The values of the effective magnetisation were extracted from the FMR spectra measured at different sample orientations in the applied magnetic field. Dose dependencies of the FMR absorption intensity and effective magnetisation were obtained for the annealed films. The magnetic properties of the synthesised cobalt–polymer composite materials and their modification due to the annealing treatment are discussed.

Polyimide foils were implanted with 40 keV Fe+ and Co- to doses of 0.25-1.5×1017 ions/cm2. Electron microscopy studies showed the formation of iron and cobalt nanoparticles in the implanted polymer layer with a thickness of about 70 nm. The size and shape of the ion-synthesized metal nanoparticles depend on the implantation parameters and subsequent thermal annealing. A ferromagnetic resonance (FMR) response was found in the iron-implanted samples as well as in the annealed cobalt and iron samples. The effective magnetization values of the metal/polymer composite layers were extracted from the FMR spectra and plotted as a function of implantation dose. The magnetic properties of the iron and cobalt nanoparticles in polyimide are compared and discussed.

40 keV Fe+ ions were implanted into polyimide (PI) films with doses of (0.25–1.25)×1017 ions/cm2 at ion current densities of 4, 8 and 12 μA/cm2. Transmission electron microscopy study showed that iron granular films consisting of isolated metal particles with lateral sizes of 25–300 nm were formed in the irradiated (carbonised) layer of polymer. An influence of implantation parameters and thermal annealing on magnetic properties of the synthesised iron films was investigated by the ferromagnetic resonance technique. It was found that the metal/polymer composite layer is formed at highest dose of 1.25×1017 ions/cm2 and it reveals the characteristics of a continuous magnetic film: remanent magnetisation and coercive field.

In this work, composition of wet deposition in Kaynarca, Turkey is studied by collecting precipitation samples during more than a 2-year period. August 1993-November 1995. Concentrations of the main cations Na+, Mg2+, Ca2+, K+, NH4+ and the main anions Cl-, NO3- and SO4(2-) together with pH were studied. The average pH value at Kaynarca was near neutral, 5.59. Results indicated that SO4(2-) concentration in precipitation was very high, as was Ca2+, neutralizing the acidity. Acidic wet deposition samples were generally obtained in winter. Enrichment factors for sea and soil indicate the strong effects of sea and soil, specifically limestone on the composition of precipitation. Non-sea salt fractions of SO4(2-) were found to range from 0.955 to 0.980, showing the effect of non-sea sources, especially emissions from fossil-fuel combustion, on the pH of samples. Trajectory analysis showed that cyclones originating from northwestern, central and eastern parts of Europe have generally high sulfate and nitrate concentrations and low pH.