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The exploration of mining has often been limited by time-consuming methods of analysis. This paper introduces Data Envelopment Analysis (DEA) as a new tool for the exploration phase of mining. DEA is a non-parametric method for data fusion, and it is used alongside with the on-site Raman analysis. Ten meters of halved rock drillcore from the Kittil mine (Suurikuusikko deposit) were pulverised and homogenised, thus ensuring that each meter had a representative sample. These 10 samples, one for each meter, were subsequently measured with a grid measurement (32×32 measurement each) using the Raman setup. All the data points were analysed using the point-count method. After identifying the frequency at which potentially valuable minerals appear in the samples, this information was analysed using DEA. The study ends by presenting an efficiency score for each meter of drillcore. These efficiency scores enable geologists to judge more rapidly which parts of the drillcore must be logged more carefully. In addition, Principal Component Analysis (PCA) is discussed as an alternative for producing similar results to DEA. [ABSTRACT FROM AUTHOR]

Rutile to anatase phase transition in Nb-doped thin films grown by RF magnetron sputtering method, annealed in H 2 atmosphere at 460 °C for 30 min using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-VIS spectroscopy and Raman analysis was found. XRD study reveals transformation of rutile fraction phase presented in mixed structure of Nb:TiO 2 thin films before annealing in H 2 environment to anatase and increases the crystallites size from 21 nm to 32 nm. The UV-VIS spectroscopy shows that the optical band gap of the films increases as the Nb concentration increases. Moreover, annealing in H 2 additionally increases the band gap. The increase of the optical band gap of the films is explained by the presence of both anatase phase and Nb 2 O 5 inclusions as shown by analysis of Raman spectra. [ABSTRACT FROM AUTHOR]

We report the deposition of tin sulfide (Sn 2 S 3 ) thin films by co-evaporation technique at different substrate temperatures. The influence of substrate temperature on the structural and optical properties of the thin films is investigated. X- ray diffraction (XRD) analysis and Micro-Raman studies confirm the formation of Sn 2 S 3 phase. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used to examine the surface morphology. The transmission spectra of the deposited Sn 2 S 3 thin films have been recorded in the wavelength range of 200–3000 nm using UV–vis-NIR spectrometer. Film thickness (d) and optical constants such as refractive index (n), extinction coefficient (k), real (ε 1 ) and imaginary (ε 2 ) parts of the dielectric constants of thin films are estimated from the optical transmittance. The optical band gaps of the deposited films at different substrate temperatures are in the range of 1.46–1.64 eV. Hall effect measurements confirm the n-type nature of the as-prepared Sn 2 S 3 thin films. [ABSTRACT FROM AUTHOR]

BaBi x La x Fe (12−2 x ) O 19 (0.0≤ x ≤0.5) hexaferrites were synthesized by solid state synthesis route and the effects of Bi, La substitutions on structural, magnetic and optical properties were investigated. X-ray powder diffraction, Scanning electron microscopy, Vibrating sample magnetometer, and Percent diffuse reflectance spectroscopy were used to study the physical properties. Room temperature specific magnetization (M–H) curves revealed the ferromagnetic nature of all products. The increasing Bi, La compositions increased the magnetic properties at different magnitudes with respect to undoped BaFe 12 O 19 sample. The maximum values of remnant specific magnetization ( M r =30.3 emu/g), extrapolated specific saturation magnetization ( M s =62.12 emu/g), and magneton number ( n B =16.27) were recorded from BaBi 0.2 La 0.2 Fe 11.4 O 19 hexaferrite. The average crystallite size varies in a range of (37.35–51.36) nm. The coercive field ( H c ) of undoped hexaferrites is 1180 Oe and increased to maximum 2320 Oe belonging to BaBi 0.4 La 0.4 Fe 11.2 O 19 . Magnetic anisotropy was confirmed as uniaxial and calculated effective anisotropy constants ( K eff ) are between 4.27×10 5 Ergs/g and 5.05×10 5 Ergs/g. The high magnitudes of magnetocrystalline anisotropy ( H a ) above than 16,200 Oe revealed that all samples are magnetically hard materials. The Tauc plots were drawn to extrapolate the direct optical energy band gap ( E g ) of hexaferrites. The E g values decreased from 1.76 eV to 1.47 eV with increasing Bi, La compositions. [ABSTRACT FROM AUTHOR]

A series of Mn–Zn Ferrite nanoparticles (<15 nm) with formula Mn x Zn 1− x Fe 2 O 4 (where x =0.00, 0.35, 0.50, 0.65) were successfully prepared by citrate-gel method at low temperature (400 °C). X-ray diffraction analysis confirmed the formation of single cubic spinel phase in these nanoparticles. The FESEM and TEM micrographs revealed the nanoparticles to be nearly spherical in shape and of fairly uniform size. The fractions of Mn 2+ , Zn 2+ and Fe 3+ cations occupying tetrahedral sites along with Fe occupying octahedral sites within the unit cell of different ferrite samples are estimated by room temperature micro-Raman spectroscopy. Low temperature Mossbauer measurement on Mn 0.5 Zn 0.5 Fe 2 O 4 has reconfirmed the mixed spinel phase of these nanoparticles. Room temperature magnetization studies (PPMS) of Mn substituted samples showed superparamagnetic behavior. Manganese substitution for Zn in the ferrite caused the magnetization to increase from 04 to18 emu/g and Lande's g factor (estimated from ferromagnetic resonance measurement) from 2.02 to 2.12 when x was increased up to 0.50. The FMR has shown that higher Mn cationic substitution leads to increase in dipolar interaction and decrease in super exchange interaction. Thermomagnetic ( M – T ) and magnetization ( M – H ) measurements have shown that the increase in Mn concentration (up to x =0.50) enhances the spin ordering temperature up to 150 K (blocking temperature). Magnetocrystalline anisotropy in the nanoparticles was established by Mossbauer, ferromagnetic resonance and thermomagnetic measurements. The optimized substitution of manganese for zinc improves the magnetic properties and makes these nanoparticles a potential candidate for their applications in microwave region and biomedical field. [ABSTRACT FROM AUTHOR]

It is now clear that growing flat graphene nanostructures from the gas phase on planar substrates is possible. One of the keys to success —particularly in producing a very large specific surface in a reduced space— is the use of 3D carbon nanostructures (i.e., vertical graphene nanowalls, VGNWs) over a planar substrate as a growth template for the deposition of electrochemically active materials (as, for example, transition metal oxides (TMO)). Vertical graphene nanowalls, also known as petal-like, vertical graphene flakes or vertical graphene, can achieve a very large specific surface area of 1100 m2/g, which is comparable to or greater than that of carbon nanotubes —the reference material for its use in high-performance supercapacitors or in other energy-related applications requiring a large active surface area. Vertical graphene nanowalls also exhibit high vertical and in-plane electrical conductivity when grown on metal electrodes, which benefits their use in electrochemical applications. Here, we focus on the growth of VGNWs on flexible stainless-steel substrates (SS310), in principle suitable for applications to electrodes of electrochemical systems (batteries, supercapacitors, catalysts), by inductively coupled plasma chemical vapour deposition (ICP-CVD), from methane as a carbon precursor, in a wide range of temperatures (575 to 900 °C). We will discuss the effect of growth temperature on morphological and structural characteristics of VGNWs based on the results of Raman spectroscopy and field emission scanning electron microscopy (FE-SEM) analysis. Because the nanostructures of graphene nanowalls reported to date are, for the most part, based on multi-layered graphene, here we seek to highlight the effect of temperature on the number of atomic layers of VGNW. In the 700–750 °C range, and under the plasma conditions explored, vertical graphene nanowalls are bilayer, which is foreseen to directly affect the magnitude of the VGNW specific surface. [Display omitted] • Growth of graphene nanowalls by ICP-CVD on stainless steel in the range 675–775 °C. • Monatomic two-layer graphene nanowalls grown at 750 °C by ICP-CVD. • Defects mainly at the edges and not at the faces of the graphene nanowalls. • Easy anchorage of MeO x particles on edges and high chemical stability of the system. [ABSTRACT FROM AUTHOR]

In this paper, cadmium oxide (CdO) was effectively developed on copper selenide (CuSe) nanoparticles via the wet-chemical method for the first time to explore their electrochemical properties for hybrid supercapacitors (HSC). The XRD Raman analysis proves the successful formation of the CdO, CuSe, and CdO-CuSe nanocomposite. The morphological results exposed that CdO and CuSe are composed of irregular particles-like morphology. Cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analysis demonstrated the battery-type behavior of the electrode materials, with prominent redox peaks and voltage plateau in the GCD profile with good reversibility. Interestingly, it was observed that the freshly prepared CdO-CuSe electrode displays a relatively higher capacity (386 C/g) compared to CdO and CuSe electrodes (175 and 216 C/g). Furthermore, we built a CdO-CuSe//AC HSC, which expanded the voltage limit to 1.8 V. It delivered a high energy and power densities of 51 Wh kg−1 and retained 16 Wh kg−1 when power density reached its maximum value of 6488 W kg−1. More importantly, a stable cycling performance (94.8%) was attained after 9000 cycles at the highest current rate of 15 A g−1, which can be attributed to the high conductivity, which offers more active sites for electrolyte ions on the electrode surface. [Display omitted] • CdO-CuSe nanocomposite was successfully prepared via the wet chemical method for the first time. • CdO-CuSe electrode exhibits a remarkable capacitive performance (385 C/g) compared to their pure counterparts in a three-electrode setup. • A CdO-CuSe//AC HSC was assembled, which delivered a high energy density of 51 Wh kg−1 and power density of 6488 W kg−1. [ABSTRACT FROM AUTHOR]

For the first time, convective assembly technique was used for coating graphene oxide (GO) nano-sheets on an indium free, low cost and good conducting Nb doped TiO2 (TNO) thin films as a transparent conducting oxide (TCO) template. This construction enhances the charge transport as well as getting the benefit of photocatalysis activity of graphene-TiO2 structure. Surface morphology was investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). TCO template showed a smooth surface with root mean square value (RMS) of 0.5 nm. The assembled GO thin layer has wide continuous area, with wrinkles, crumbles and folding at the edges. Raman analysis was used to investigate the phonon lattice vibrations within the films. According to photo-catalytic activity measurements, GO on TNO films exhibited better photo-catalytic efficiency. The proposed hybrid material structure exhibited transparent conducting property and photo-catalytic activity. [ABSTRACT FROM AUTHOR]

Convective assembly technique which is a simple and scalable method was used for coating uniform graphene oxide (GO) nanosheets on zinc oxide (ZnO) thin films. Upon UV irradiation, an enhancement in the on-off ratio was observed after functionalizing ZnO films by GO nanosheets. The calculations of on-off ratio, the device responsivity, and the external quantum efficiency were investigated and implied that the GO layer provides a stable pathway for electron transport. Structural investigations of the assembled GO and the heterostructure of GO on ZnO were performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The covered GO layer has a wide continuous area, with wrinkles and folds at the edges. In addition, the phonon lattice vibrations were investigated by Raman analysis. For GO and the heterostructure, a little change in the ratio between the D-band and G-band was found which means that no additional defects were formed within the heterostructure. [ABSTRACT FROM AUTHOR]

Stress corrosion cracking of advanced powder metallurgy technology (APMT) and T91 (UNS K90901, ferritic-martensitic) steels were investigated in the as-received and proton-irradiated conditions in simulated boiling water reactor environment (2 ppm O2) using constant extension tensile tests at 288°C at a strain rate of 3x10-7s-1. Significant stress corrosion cracking was not observed in the as-received condition. A few cracks, perpendicular the loading direction, were observed in the proton-irradiated (5 dpa) specimen of T91. No intergranular fracture was observed on the fracture surfaces of as-received and proton-irradiated specimens of T91. No cracking was observed for APMT in un-irradiated and proton-irradiated (5 dpa) conditions. Results indicate that both APMT and T91 are highly resistant to stress corrosion cracking in a reactor environment and that irradiation to 5 dpa does not appreciably increase susceptibility. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO)-phosphor hybrid nanoscrolls were synthesized using a simple chemical method. The GO-phosphor ratio was varied to find the optimum ratio for enhanced optical characteristics of the hybrid. A scanning electron microscope analysis revealed that synthesized GO scrolls achieved a length of over 20 µm with interior cavities. The GO-phosphor hybrid is extensively analyzed using Raman spectroscopy, suggesting that various Raman combination modes are activated with the appearance of a low-frequency radial breathing-like mode (RBLM) of the type observed in carbon nanotubes. All of the synthesized GO-phosphor hybrids exhibit an intense luminescent emission around 540 nm along with a broad emission at approximately 400 nm, with the intensity ratio varying with the GO-phosphor ratio. The photoluminescence emissions were gauged using Commission Internationale d'Eclairage (CIE) coordinates and at an optimum ratio. The coordinates shift to the white region of the color spectra. Our study suggests that the GO-phosphor hybrid nanoscrolls are suitable candidates for light-emitting applications. [ABSTRACT FROM AUTHOR]

Ultrananocrystalline diamond film was deposited by microwave chemical vapor deposition (CVD) system using Ar-CO 2 -CH 4 as gas source. The effects of process conditions on the morphology of diamond film were investigated. Results show that the compact ultrananocrystalline films with thickness of 5 μm, crystal size of 20 nm and surface roughness below 16 nm can be deposited. The deposition rate is significantly improved by adding CO 2 into the Ar-CH 4 system. However, the parameter window of gas source for the deposition of compact nanodiamond films is quite narrow when this gas source is employed. Further research is needed to investigate the reasons and optimal process condition. [ABSTRACT FROM AUTHOR]

In this work, we report the synthesis of Ni doped CdS cowrie-shell architectures and submicron balls like structures via low temperature chemical bath deposition method. The as-synthesized materials were systematically characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDAX), Raman spectroscopy and FTIR spectra. XRD results revealed the existence of cubic phase of CdS based material. SEM pictures depicted the growth of well define morphologies i.e. cowries-shell and submicron balls. Deposition time and dopant played significant role in the growth of CdS based different architectures. The EDAX spectra confirmed the presence of Ni into the CdS lattice. Surface structure of synthesized material was derived by FTIR analysis. [ABSTRACT FROM AUTHOR]

This work reports the synthesis by solid–state reaction of Cu 2 Fe 1- x Co x SnS 4 solid solutions. Crystal structures of Cu 2 Fe 0.8 Co 0.2 SnS 4 and Cu 2 Fe 0.6 Co 0.4 SnS 4 were investigated by single crystal X-ray diffraction. Both phases crystallize in the tetragonal stannite-type structure. The volume of the tetrahedral [MS 4 ] (M = Fe, Co) presented the highest distortion, with Edge-Length Distortion (ELD) indices ∼2% from the ideal tetrahedron. The powder X-ray diffraction (XRD) patterns of Cu 2 Fe 1- x Co x SnS 4 ( x = 0.2, 0.4, 0.6 and 0.8) has been refined by Rietveld method. No secondary phases were detected in XRD patterns. An analysis of the vibrational properties of Cu 2 Fe 1- x Co x SnS 4 was performed using Raman scattering measurements. The Raman peaks were analyzed by fitting of the spectra and subsequently identifying the vibrational modes by comparison with experimental and theoretical data from Cu 2 FeSnS 4 (CFTS) and Cu 2 CoSnS 4 (CCTS) end-members. The spectra from Cu 2 Fe 1- x Co x SnS 4 show that there is a variation in the frequency of the main A 1 peak at ∼320 cm −1 together with a decrease in the secondary mode intensity at ∼285 cm −1 . Full Width at Half Maximum (FWHM) and the intensity of the Raman peaks reflect the high crystallinity of Cu 2 Fe 1- x Co x SnS 4 solid solutions. The oxidation states of the metals were confirmed by temperature-dependent magnetization measurements performed in the antiferromagnetic Cu 2 Fe 1- x Co x SnS 4 solid solutions. [ABSTRACT FROM AUTHOR]

Silver containing amorphous carbon films were deposited on Si wafer using a hybrid deposition process combining d.c. magnetron sputtering and PECVD. The concentration of Ag in the films was varied from 1.3 to 8.3 at % by changing d.c. magnetron current of Ag target. The influence of incorporated Ag in the a-C:H on the atomic bond structure of the films were investigated by XPS, FTIR, Raman, and HRTEM methods of analysis. The XPS, FTIR, and Raman studies demonstrated that as the silver concentration increased in the a-C:H, sp2 bonding content increased and a-C:H films changed to more graphitic structure. The high resolution TEM cross sectional studies revealed that crystalline Ag particles formed with a size in the range of 2-4 nm throughout an amorphous a-C:H matrix. [ABSTRACT FROM AUTHOR]

The effect of annealing temperature and duration on the growth and properties of Cu 2 SnS 3 films, deposited by co-evaporation of elemental Cu, Sn and S onto soda-lime glass substrates held at 350 °C is investigated. X-ray diffraction and Raman spectroscopy studies were used for phase identification. The as-deposited films are multi-phase containing Cu 2 SnS 3 and the secondary phases Cu 4 SnS 4 , Cu 1.9375 S & SnS. Films annealed at 550 °C and 580 °C under sulfur atmosphere are found to be monoclinic Cu 2 SnS 3 with minor Cu 1.9375 S. The direct optical band gap and optical absorption coefficient of monoclinic Cu 2 SnS 3 phase are found to be 0.86 ± 0.03 eV and >10 4 cm −1 respectively. The electrical resistivity of the films is found to be in the range 0.02−0.35 Ω-cm depending on the annealing conditions. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide, RGO (also called chemically modified graphene, CMG) was synthesized by a simple hydrothermal method, with graphite oxide (GO), prepared by the modified Hummers method, served as the raw material. Structural and morphological studies indicate the degree of reduction is dependent on the temperature, which is also verified by Raman analysis. The variation in interlayer distance and the intensity ratio of the D to G Raman modes ( I D / I G ) indicates higher reaction temperature can accelerate the reduction of GO. The conductivity also varies with the degree of reduction, as verified by electrochemical analyzer. Moreover, the reaction process affects organic functional groups, the mechanism during the reaction process is discussed. [ABSTRACT FROM AUTHOR]

• Irradiation of GaN epilayers with light ions grown by hydride vapor-phase epitaxy. • Analysis of Raman spectrum by the Lorentz fitting model. • Carrier Concentration, biaxial stress and phonon lifetime calculations from Raman peak. • Effect of ions fluencies on phonon lifetime and carrier concentration. • Defects analysis of GaN epilayer from the photoluminescence spectrum. Gallium Nitride (GaN) epilayer grown by Hydride Vapor-Phase Epitaxy was irradiated with 100 MeV O7+ light ions for different fluences. The X-ray diffraction results confirmed that all the grown epilayers have wurtzite structure. The thickness of the pristine GaN is measured by cross-section scanning electron microscopy. From atomic force microscopy, the irradiated sample's surface morphology and root mean square values were analyzed. The stopping range of ions in the materials calculation provided the projected range for the irradiation ions. From Raman spectroscopy, Raman active mode of E H 2 and A 1 (LO) vibration was observed. These Raman modes were fitted by the Lorentz fitting method for line-shape model identification to calculate the area under the curve, full-width half maximum, and peak shift position. The biaxial stress, carrier concentration, and phonon lifetime for both pristine and irradiated GaN epilayers were obtained from the Raman active mode. The results indicated that the carrier concentration increases for higher fluences due to the defect formations. The photoluminescence spectrum was measured for all the epilayers and defect-induced photoluminescence emission was obtained for these irradiation epilayers. [ABSTRACT FROM AUTHOR]

A uniform dispersion of black TiO 2 nanoparticles and WO 3 nanorods on rGO nanosheets was assessed for its photoelectrochemical water splitting activity. A facile solution-based approach was employed to synthesize the black TiO 2 nanoparticles and WO 3 nanorods, whereas the modified Hummer's method was used to prepare the rGO nanosheets. The composite nanostructure was obtained using a solvothermal approach. Visible light absorption was improved significantly, and the bandgap was narrowed for nanocomposites (1.76 eV) than W-TiO 2 nanoparticles (3.10 eV). The structural changes were validated using various analytical techniques like XRD, Raman, and XPS analysis. The morphology of the individual constitutions and composites was examined by TEM. Photoelectrochemical analysis showed that the composite nanostructures of black TiO 2 /WO 3 /rGO exhibited enhanced water splitting activity under visible light irradiation (0.83 mA cm−2 at 0 V). This enhancement was attributed mainly to the more efficient photoinduced charge (electron–hole) separation and transportation involved in the composite nanostructures. Schematic diagram for the proposed mechanism of heterojunction photocatalysis for the hydrogen production. [Display omitted] • Black TiO 2 /WO 3 /rGO nanocomposites were prepared as photoanode. • The bandgap energy of the composite was significantly narrowed to 1.76 eV. • Black TiO 2 /WO 3 /rGO nanocomposites exhibit enhanced visible-NIR light absorption. • The enhanced photocurrent density of 0.83 mA cm−2 at 0 V was achieved. • The enhancement is due to more efficient charge separation and transportation. [ABSTRACT FROM AUTHOR]

Thermocatalytic decomposition of methane is an alternative route for the production of CO x -free hydrogen and carbon nanomaterials. In this work, a set of novel Ni, Co and Fe based bimetallic catalysts supported over mesoporous SBA-15 was synthesized by a facile wet impregnation route, characterized for their structural, textural and reduction properties and were successfully used for the methane decomposition. The fine dispersion of metal oxide particles on the surface of SBA-15, without affecting its mesoporous texture was clearly shown in the low angle X-ray diffraction patterns and the transmission electron microscopy (TEM) images. The nitrogen sorption analysis showed the reduced specific surface area and pore volume of SBA-15, after metal loading due to the partial filling of hexagonal mesopores by metal species. The results of methane decomposition experiments indicated that all of the bimetallic catalysts were highly active and stable for the reaction at 700 °C even after 300 min of time on stream (TOS). However, a maximum hydrogen yield of ∼56% was observed for the NiCo/SBA-15 catalyst within 30 min of TOS. A high catalytic stability was shown by the CoFe/SBA-15 catalyst with 51% of hydrogen yield during the course of reaction. The catalytic stability of the bimetallic catalysts was attributed to the formation of bimetallic alloys. Moreover, the deposited carbons were found to be in the form of a new set of hollow multi-walled nanotubes with open tips, indicating a base growth mechanism, which confirm the selectivity of SBA-15 supported bimetallic catalysts for the formation of open tip carbon nanotubes. The Raman spectroscopic and thermogravimetric analysis of the deposited carbon nanotubes over the bimetallic catalysts indicated their higher graphitization degree and oxidation stability. [ABSTRACT FROM AUTHOR]

Pure and Cu doped ZnO nanorods array are synthesized via two step chemical bath deposition method. The seed layer is prepared by successive ionic layer adsorption reaction (SILAR) method. The synthesized materials have been systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDAX), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) spectroscopy. SEM pictures show the existence of vertically well aligned hexagonal ZnO nanorods. EDAX spectrum confirms the presence of Cu in ZnO nanorods. High intense peak of (0 0 2) plane and E 2 high mode for XRD and Raman spectrum respectively, suggest the ZnO nanorods are adopted c -axis orientation perpendicular to substrate. XRD and Raman analysis shows the presence of tensile strain in Cu doped ZnO nanorods. Effect of Cu doping on lattice constants, unit cell volume and Zn–O bond length of ZnO nanorods have also been studied. Room temperature PL measurement exhibits two luminescence bands in the spectra i.e. UV emission centered at 3.215 eV and a broad visible band. Theoretical investigation for capping action of triethanolamine is done by Hartree–Fock (HF) method with 3-21G basis set using Gaussian 09 program package. [ABSTRACT FROM AUTHOR]

La 1− x Ba x InO 3− δ system was synthesized to understand the phase formation and their relationship with conduction phenomena. Rietveld analysis has been performed to confirm the presence of crystalline phases. At room temperature, the system is a single phase up to x =0.05 with space group Pnma . However, higher concentration of dopant leads to formation of cubic and orthorhombic phases for x =0.1–0.15 samples. Raman spectra further verified Ba-substitution at La-site in lanthanum indate. Ac conductivity has been measured as a function of temperature and Ba content. The highest conductivity observed is ~3 mS cm −1 for x =0.1 sample at 700 °C. The activation energy indicates that the nature of present samples is like oxide ion conductors and is almost invariant with increasing Ba-content. The thermal expansion coefficient (TEC) of present samples is in the order as required for SOFC applications. [ABSTRACT FROM AUTHOR]

The stability of stationary phases on temperature and pH is especially important for separation techniques because it extends the possibilities of applications. In the present paper, the high-resolution continuum source graphite furnace atomic absorption spectrometry HR-CS-GF-AAS and confocal Raman microscopy were successfully used to evaluate stability of silica sorbent modified with polyaniline (Si-PANI) on acidic, neutral and alkaline media and elevated temperature. The solutions at pH range 1–12 were passed through the SPE cartridges, the eluates were collected and an amount of dissolved silica was analyzed. Furthermore, the quality of polyaniline film and its spatial distribution were verified by confocal Raman microscopy. The solubility of silica occurred significantly lower for Si-PANI adsorbent comparing to silica and RP-18. Our research shows that covering the particles of silica with polyaniline protects the surface of support material against the drastic pH value. The results obtained by Raman analyses confirm the high stability of polyaniline layer at a temperature range of 30–70 °C and at pH from 1 to 12. The sorbent may be used in separation techniques, e.g. as a stationary phase for liquid chromatography in the wide pH and temperature range. [ABSTRACT FROM AUTHOR]

Compositions with x ≤ 0.30 in the system (1 - x)Pb(Zr0.52Ti0.48)O3-(x)BiFeO3 were synthesized by sol-gel method. Rietveld analysis of X-ray diffraction data reveals tetragonal structure (P4mm) for x ≤ 0.05 and monoclinic (Cm) phase along with the existence of tetragonal phase for 0.10 ≤ x ≤ 0.25 and monoclinic phase for x = 0.30. Transformation of E(2TO) and E + B1 vibrational modes in the range 210-250 cm-1 (present for x ≤ 0.25) into A' + A" modes at ~236 cm-1 for x = 0.30, and occurrence of new vibrational modes A' and A" in Raman spectra for x ≥ 0.10 unambiguously support the presence of monoclinic phase. Occurrence of remnant polarisation and enhanced magnetization with concentration of BiFeO3 indicates superior multiferroic properties. Variation of magneto-capacitance with applied magnetic field is a strong evidence of magneto-electric multiferroic coupling in these materials. [ABSTRACT FROM AUTHOR]

There exist many different ways of analysing rock drillcore samples. Here the interest is on the faster exploration activities of mining. A capable, rapid and online measurement technique is presented for analysing the mineral composition of rock drillcore samples. Raman analysis is an accurate but slow method of analysing rock drillcore samples. On the other hand, laser-induced fluorescence (LIF) can be used as a rapid method to produce a colour map of minerals based on their fluorescence. These two methods can be combined by calibrating LIF measurements with Raman results. This paper presents a combination of Raman analysis with LIF image analysis to form a rapid online mineral exploration technique used on the rock drillcore samples. To the best knowledge of the authors, the combination of LIF and Raman in the study of rock drillcore has not been published. The sample set under study is segments of rock drillcore collected from a Ni–Cu multi-metal mine situated in Kevitsa, Finland. Scanning drillcore samples using LIF technique produces images which present a map of colours based on emissions of fluorescent minerals. Some parts of the sample set, based on the exposed colours, are measured through Raman spectroscopy and the minerals are identified using reference spectra from a public source. Identification of minerals through Raman analysis is done using Non-Negative Least Squares (NNLS) method. Results show that colours of LIF images correspond to minerals identified through Raman analysis. The combination of LIF and Raman is then used to produce mineral maps of the drillcore samples and finally an estimation of the mineral abundance per units of drillcore area is developed. [ABSTRACT FROM AUTHOR]

This study evaluated the ability of different in vitro mechanical loading tests to promote new mineral formation at bonded dentin interfaces. This research demonstrated a sequential transition in the dentin remineralizing procedure through the analysis of the mineral and matrix gradients. Mechanical loading in phosphoric acid (PA)-treated samples promoted a generalized increases in relative presence of minerals, crystallinity, ratio of phosphate peaks and a decrease in the gradient of mineral content. The organic component showed, in general terms, an increase in crosslinking. $$\upalpha $$ -helices incremented in sine and square waveform loading. In EDTA + SB specimens, the relative mineral concentration incremented when loading in hold, in general. Nonuniform parameters of Bis-GMA and adhesive penetration were encountered in both groups. PA + SB promoted the highest dentin mineralization degree when loading in square, based on the increase in the relative presence of minerals and crystallinity. EDTA + SB produced any advance crystallographic maturity at the interface. High crosslinking parameters and conformational changes in proteins in PA-treated specimens indicated, indirectly, that the first remineralization is intrafibrillar. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the effect of Fe additions on combustion velocity and phases that are formed after synthesis in the TiO2-Al-C system. Before experimental tests, thermodynamic calculations were performed to determine the range that Fe can be added to the reaction and remain self sustaining. According to the Merzhanov criterion, if the amount of Fe is lower than 53.13 wt.%, the adiabatic temperature of the reaction is higher than 1800 K and therefore the reaction proceeds in the self sustaining mode. But, experimental observations showed that the reaction became unstable when the amount of Fe was changed from 15 to 20 wt.%, which was considerably lower than that was predicted by thermodynamic calculations. X-ray diffraction analysis indicated that Fe3Al, TiC and Al2O3 are the main phases formed in the products and additions of Fe decreased the lattice parameter of TiC. Also, Raman spectroscopy analysis showed that at higher Fe contents, oxygen dissolved in the TiC crystal structure leading to the formation of titanium oxy-carbide with lower lattice parameter and residual un-reacted carbon in the products. The adiabatic temperatures for the reactions containing 15 and 20 wt.% Fe estimated using the thermodynamic data of the new products were in conformance with the Merzhanov criterion and experimental observations. Scanning electron microscopy examinations showed that the addition of Fe decreased TiC particle size and changed their growth controlling mechanism. [ABSTRACT FROM AUTHOR]

Germanium nanowires (GeNWs) were synthesized in a low pressure chemical vapor deposition reactor (LPCVD) using a vapor-liquid-solid process (VLS). In this work, the focus is put on the characterization of these GeNWs using scanning electron microscopy (SEM) combined with Raman spectroscopy. In particular, NWs with conical shape grown at a moderate temperature (320 °C) were investigated in terms of the intensity measured for the Ge-related Raman line. The two main observations, discussed in this paper, are the anomalous magnitude of this line, as compared to measurements under the same conditions on a Ge(100) substrate, and the oscillations observed when the Raman line intensity is measured while scanning the laser beam along the axis of the conical shaped NWs, from the tip to the bottom. These effects are discussed involving the fact that optical modes appear in such NWs (both for the incident and Raman scattered light) when conditions on the diameter, the laser excitation wavelength, and substrate (on which the NWs are transferred after growth) are fulfilled. Taking into account these specific optical modes, the effects observed can be explained. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

CuZnO (CZO) films have attracted increasing amounts of attention due to their promising potential applications in semiconductor devices. ZnO shows n-type conductivity, and attempts have been made to dope several elements in ZnO to improve the electrical properties. This study investigated the electrical property transitions of CZO films and determined the copper concentration at which the conductivity of CZO films will change from n-type to p-type. In this study, CZO films were fabricated by ultrasonic spray pyrolysis with copper acetate, zinc acetate, and ammonium acetate precursor solution. The concentrations of Cu ions in the CZO films were controlled by the concentration ratios of copper acetate to zinc acetate in the precursor solutions. In addition, these samples were analyzed by Hall effect measurements, X-ray diffraction, transmittance measurements, and photoluminescence measurements. The results show that the conductivity of the CZO film changes from n-type to p-type when the copper ion concentration in the film is 5%. [ABSTRACT FROM AUTHOR]

Abstract: Titanium nitride, carbide and carbonitride coatings were synthesized on titanium substrates by the thermochemical diffusion process in ammonia, methane and varying compositions of ammonia/methane mixture, respectively. High temperature oxidation resistance of these coatings has been studied as a function of carbon to nitrogen ratio in the coatings. Oxidation experiments were conducted in a thermogravimetric analyzer in oxygen atmosphere at 800°C. XRD, SEM, EDS, XPS and Raman measurements before and after the oxidation studies revealed that the content of sp3 bonded carbon interspersed in the coatings plays a key role in deciding the oxidation resistance of the coatings. TiC with higher sp3 carbon showed maximum oxidation resistance and TiN the least. Incorporation of even a small amount of N in TiC and C in TiN is found to drastically alter their oxidation resistance. [Copyright &y& Elsevier]

Orthopedic bone devices can be prepared from the shells of giant pearl oysters. Nacre is biocompatible and composed of calcium carbonate (aragonite). Direct welding of bone onto the biomaterial surface has been reported but poorly investigated. Nacre from Pinctada maxima was used to prepare plates, screws and rods. Five sheep were implanted in the first metatarsus under general anesthesia and killed 2 months later. Bones were harvested and fixed in formalin. Analysis was performed by nanotomography and histology after embedding in poly(methyl methacrylate). Polished sections were imaged by scanning electron microscopy then analyzed on a Raman microscope. Nanotomography and histology evidenced the newly apposed bone composed of thin trabeculae with a lower mineralization than mature bone. Erosion of the nacre was also easily observed. The bone/nacre interface presented a characteristic toothed-comb appearance. Raman spectroscopy identified the typical bands of aragonite (1091 and 711 cm−1) in the devices. At a distance from the interface, the bone matrix presented the typical bands of hydroxyapatite at 960, 1044 and 594-610 cm−1 with the amide bands of collagen at 1250 cm−1. At the bone/nacre interface, a phosphate-rich layer was observed without proteins. The newly formed bone units exhibited a band at 1075 cm−1 corresponding to a high amount of B-carbonate substitution. The carbonate/phosphate ratio decreased between new and mature bone, and crystallinity was improved. Raman spectroscopy confirmed the modifications of the bone matrix around the nacre implant and the direct apposition of bone without an interposing organic layer between the calcium carbonate (nacre) and the calcium phosphate (hydroxyapatite). Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Present study demonstrates the feasibility of using oxides of Sn to fabricate the p- n junction diode and reports the device characteristics. Reactive thermal evaporation method was used to fabricate the p-type SnO and n-type SnO multilayer thin films. The x-ray diffraction (XRD) and Raman spectra depict the presence of both SnO and SnO layers. The interface of the p- n junction analyzed by cross-sectional transmission electron microscope (TEM) images and selected area electron diffraction (SAED) pattern confirmed the presence of SnO-SnO layers. The diode shows rectifying current-voltage characteristics with forward threshold voltage of 3.5 V. [ABSTRACT FROM AUTHOR]

Abstract: Eu3+-doped niobium oxyfluorosilicate glass with molar composition of 1Eu2O3+20Nb2O5+20K2O+19ZnF2+10LiF+30SiO2 (EuNKZLS) was prepared by the melt quenching method. Absorption, photoluminescence and phonon sideband (PSB) spectra were recorded to estimate the local structural evolution. The local structure around the Eu3+ ions and the phonon energy (645cm−1) of EuNKZLS glass were confirmed on the basis of PSB spectrum associated with the 7F0→5D2 transition. The structure of EuNKZLS glass in the broad compositional range has been determined from the Raman spectrum. The extent of coupling between the vibrational modes and electronic transitions along with the multiphonon relaxation process has also been discussed. [Copyright &y& Elsevier]

The effect of dysprosium (Dy) doping on the structural and dielectric properties of barium titanate (BaTiO) ceramic has been studied. Dysprosium-doped barium titanate (BT) with general formula BaDyTiO ( x = 0.0-0.1) is prepared through solid state reaction route. The XRD pattern reports the single phase tetragonal structure up to x = 0.025 with space group of P4mm and a secondary phase is observed for higher concentration of Dy. The Raman study of BaDyTiO ( x = 0.00, 0.01, 0.025) also reveals that the ceramic is showing tetragonal symmetry and with an increase in Dy doping the tetragonal phase is moving toward more symmetric phase i.e. cubic pm3m. The surface morphology of the sintered pellets shows a compact and homogeneous grain distribution with a decrease in grain size as the Dy content increases. The temperature and frequency dependency dielectric study of the ceramic compositions ( x = 0.00, 0.01, 0.025) are studied to show the effect of Dy ion on the A site of BaTiO perovskite ceramic. The dielectric constant decreases with increase in Dy content. The dielectric diffusivity increases with increase in doping concentration. The P-E hysteresis loop confirms the ferroelectric behavior of the sample with decrease in remanent polarization and increase in coercive field. [ABSTRACT FROM AUTHOR]

Highlights: [•] The amorphous Ge–Te–In films were prepared by magnetron co-sputtering method. [•] The Ge–Te–In film system has a high crystallization temperature. [•] Large redshift of the optical band gap is related to crystallization by annealing. [•] The structural rearrangements around Ge atoms occur during crystallization. [ABSTRACT FROM AUTHOR]

Highlights: [•] Silica gel with a film of polyaniline was obtained in a process in situ polymerization of aniline. [•] Uniform distribution of PANI on the surface was confirmed by Raman analysis. [•] Prepared column was tested for non-suppressed IC with spectrophotometric detection. [•] The application of silica gel modified with polyaniline for separation of selected anions with use HPIC was tested. [•] The column and optimized chromatographic system were successfully used for analysis of lake water. [ABSTRACT FROM AUTHOR]

In situ growth of upright-standing SnO2 nanoplates connected to horizontally pointed TiO2 nanoneedles to form a new, high surface area hierarchical nanostructure is proposed for the first time and envisaged in ammonia and liquid petroleum gas sensors. The increased surface area due to a hierarchical nanostructure accounts for enhanced gas sensitivity. [Copyright &y& Elsevier]

This is the first report of anthropogenic particles (APs), including microplastics and synthetic, semi-synthetic and anthropogenically-altered natural fibers, in water and sediment of the Chubut River estuary. This river is the main source of freshwater in Chubut Province (Patagonia, Argentina), where wastes and pollutants are poured and finally end in the Atlantic Ocean. The average concentration in surface and bottom water samples was 5.5 items/L, while in sediment was 175.4 items/kg dw. Raman's analysis identified particles dominated by polyethylene terephthalate (PET) (35.5 %), dye signature only (18.5) and anthropogenic cellulose (10 %). Fibers were the prevalent shape (83 %), and the chemical identification evidenced a textile origin. The highest APs concentration was found in sediments from the site with the finest grain size and the greatest amount of organic matter. Present results will provide a baseline for future studies and raise public and governmental awareness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Abstract: Nonoxide ceramics titanium carbide (TiC) has been prepared from ilmenite by using an extended arc plasma reactor under Ar atmosphere with an optimum time period of 20min. The TiC product obtained after the acid treatment is of high purity and well comparable to the commercial available powder. The XRD and Raman analyses clearly predict that the product contains only TiC matrix without having any impurity. The particle size measurement and scanning electron micrograph predict that the range of the powders is within 10μm whereas the commercial powder has a broad range from 10 to 80μm. [Copyright &y& Elsevier]