Journal of Spectroscopy http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Midinfrared FT-IR as a Tool for Monitoring Herbaceous Biomass Composition and Its Conversion to Furfural Wed, 04 Mar 2015 13:59:36 +0000 http://www.hindawi.com/journals/jspec/2015/719042/ A semiquantitative analysis by means of midinfrared FT-IR spectroscopy was tuned for the simultaneous determination of cellulose, hemicellulose, and lignin in industrial crops such as giant reed (Arundo donax L.) and switchgrass (Panicum virgatum L.). Ternary mixtures of pure cellulose, hemicellulose, and lignin were prepared and a direct correlation area/concentration was achieved for cellulose and lignin, whereas indirect correlations were found for hemicellulose quantification. Good correspondences between the values derived from our model and those reported in the literature or obtained according to the official Van Soest method were ascertained. Average contents of 40–45% of cellulose, 20–25% of hemicellulose, and 20–25% of lignin were obtained for different samples of giant reed species. In the case of switchgrass, a content of 36% of cellulose, 28% of hemicellulose, and 26% of lignin was achieved. This analysis was also carried out on giant reed and switchgrass residues after a mild hydrolysis step carried out with dilute hydrochloric acid for the production of furfural with good yield. Reasonable compositional data were obtained, thus allowing an indirect monitoring which helps the optimization of the hydrothermal pretreatment for furfural production from hemicellulose fractions. Anna Maria Raspolli Galletti, Aldo D’Alessio, Domenico Licursi, Claudia Antonetti, Giorgio Valentini, Alessandro Galia, and Nicoletta Nassi o Di Nasso Copyright © 2015 Anna Maria Raspolli Galletti et al. All rights reserved. Oxidative Stability of Baru (Dipteryx alata Vogel) Oil Monitored by Fluorescence and Absorption Spectroscopy Wed, 04 Mar 2015 11:25:48 +0000 http://www.hindawi.com/journals/jspec/2015/803705/ Baru (Dipteryx alata Vogel) is a native fruit of the Brazilian savanna that provides a nutritive oil, which also has medicinal properties. Baru fruits were collected in central-western Brazil, and the oil was obtained by pressing the seeds. The Baru oil was heated at 110°C for 24 h, and its oxidative stability was investigated by using fluorescence and absorption spectroscopy. The data showed that both absorption and fluorescence were able to precisely monitor the oil degradation induced by the thermooxidative process. The results revealed a rapid growth of the primary compounds generation in the first 16 hours of degradation. Significant amounts of secondary compounds began to be generated after 14 hours. Vanessa D. Silva, José N. Conceição, Ivan P. Oliveira, Caroline H. Lescano, Rozanna M. Muzzi, Omar P. S. Filho, Edemilson C. Conceição, Gleison A. Casagrande, and Anderson R. L. Caires Copyright © 2015 Vanessa D. Silva et al. All rights reserved. Effect of the Unsaturation of the Hydrocarbon Chain of Fatty-Amides on the Corrosion of Carbon Steel Using EIS and Real-Time Corrosion Measurement Mon, 02 Mar 2015 09:32:17 +0000 http://www.hindawi.com/journals/jspec/2015/184140/ Fatty-amide derivatives were evaluated to study the effect of the double bonds into the hydrocarbon chain (C18) on the corrosion behavior of carbon steel. Electrochemical impedance spectroscopy (EIS) and real-time corrosion measurements were used to evaluate the inhibition mechanism of the fatty-amides on carbon steel in CO2-saturated (3% NaCl + 10% diesel) emulsion at 50°C. EIS results demonstrated that the unsaturation present into the hydrocarbon chain contributes to the efficiency of fatty-amides, because they can be adsorbed on the metal surface by a flat-adsorption process reducing the presence of active sites and blocking the corrosion process and preventing the diffusion of corrosive species, such as H2O, H+, Cl−, and . Real-time corrosion measurements also indicated that the effectiveness of the inhibitors is dependent on the unsaturation into the hydrocarbon chain, being also a good technique to determine the stability of the adsorption process of the inhibitors. J. Porcayo-Calderon, I. Regla, E. Vazquez-Velez, L. M. Martinez de la Escalera, J. Canto, and M. Casales-Diaz Copyright © 2015 J. Porcayo-Calderon et al. All rights reserved. A Simple Approach to Distinguish Classic and Formaldehyde-Free Tannin Based Rigid Foams by ATR FT-IR Thu, 26 Feb 2015 10:22:03 +0000 http://www.hindawi.com/journals/jspec/2015/902340/ Tannin based rigid foams (TBRFs) have been produced with formaldehyde since 1994. Only recently several methods have been developed in order to produce these foams without using formaldehyde. TBRFs with and without formaldehyde are visually indistinguishable; therefore a method for determining the differences between these foams had to be found. The attenuated total reflectance infrared spectroscopy (ATR FT-IR) investigation of the TBRFs presented in this paper allowed discrimination between the formaldehyde-containing (classic) and formaldehyde-free TBRFs. The spectra of the formaldehyde-free TBRFs, indeed, present decreased band intensity related to the C–O stretching vibration of (i) the methylol groups and (ii) the furanic rings. This evidence served to prove the chemical difference between the two TBRFs and explained the slightly higher mechanical properties measured for the classic TBRFs. Gianluca Tondi, Martin Link, Chuan Wei Oo, and Alexander Petutschnigg Copyright © 2015 Gianluca Tondi et al. All rights reserved. Fourier Transform Infrared Spectroscopic Imaging of Fracture Healing in the Normal Mouse Thu, 26 Feb 2015 06:34:38 +0000 http://www.hindawi.com/journals/jspec/2015/659473/ Fourier transform infrared spectroscopic imaging (FTIRI) was used to study bone healing with spatial analysis of various callus tissues in wild type mice. Femoral fractures were produced in 28 male C57BL mice by osteotomy. Animals were sacrificed at 1, 2, 4, and 8 weeks to obtain callus tissue at well-defined healing stages. Following microcomputerized tomography, bone samples were cut in consecutive sections for FTIRI and histology, allowing for spatial correlation of both imaging methods in different callus areas (early calcified cartilage, woven bone, areas of intramembranous and endochondral bone formation). Based on FTIRI, mineral/matrix ratio increased significantly during the first 4 weeks of fracture healing in all callus areas and correlated with bone mineral density measured by micro-CT. Carbonate/phosphate ratio was elevated in newly formed calcified tissue and at week 2 attained values comparable to cortical bone. Collagen maturity and mineral crystallinity increased during weeks 1–8 in most tissues while acid phosphate substitution decreased. Temporal and callus area dependent changes were detected throughout the healing period. These data assert the usefulness of FTIRI for evaluation of fracture healing in the mouse and its potential to evaluate pathologic fracture healing and the effects of therapeutic interventions. Hans Gollwitzer, Xu Yang, Lyudmila Spevak, Lyudmila Lukashova, Allina Nocon, Kara Fields, Nancy Pleshko, Hayden William Courtland, Mathias P. Bostrom, and Adele L. Boskey Copyright © 2015 Hans Gollwitzer et al. All rights reserved. Green Synthesis and Characterization of Carbon Nanotubes/Polyaniline Nanocomposites Mon, 23 Feb 2015 14:46:10 +0000 http://www.hindawi.com/journals/jspec/2015/297804/ Carbon nanotubes/polyaniline (CNT/PANI) nanocomposites were synthesized by the interfacial polymerization of aniline in the presence of CNTs using two green solvents, water and an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4]), as the two phases. The formation and incorporation of PANI on the surface of the CNTs were confirmed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy. The analyses showed that the surface of the CNTs was coated with different morphologies of thin PANI layers depending on whether a HCl or HNO3 solution was used. The thermal stability of the composites was much better than that of the bare CNTs and pure PANI. The as-prepared composites were also used to modify the nickel foam electrodes for characterization of the electrochemical properties. Van Hoa Nguyen and Jae-Jin Shim Copyright © 2015 Van Hoa Nguyen and Jae-Jin Shim. All rights reserved. SrAl2O4:Eu2+(,Dy3+) Nanosized Particles: Synthesis and Interpretation of Temperature-Dependent Optical Properties Mon, 23 Feb 2015 07:58:58 +0000 http://www.hindawi.com/journals/jspec/2015/541958/ SrAl2O4 nanosized particles (NPs) undoped as well as doped with Eu2+ and Dy3+ were prepared by combustion synthesis for the discussion of their intensively debated spectroscopic properties. Emission spectra of SrAl2O4:Eu2+(,Dy3+) NPs are composed by a green band at 19 230 cm−1 (520 nm) at room temperature, assigned to anomalous luminescence originated by Eu2+ in this host lattice. At low temperatures, a blue emission band at 22 520 cm−1 (444 nm) is observed. Contrary to most of the interpretations provided in the literature, we assign this blue emission band very reliably to a normal 4f6(7FJ)5d(t2g)→4f7(8S7/2) transition of Eu2+ substituting the Sr2+ sites. This can be justified by the presence of a fine structure in the excitation spectra due to the different 7FJ levels () of the 4f6 core. Moreover, Fano antiresonances with the 6IJ () levels could be observed. In addition, the Stokes shifts ( 980 cm−1 and 5 270 cm−1 for the blue and green emission, resp.), the Huang-Rhys parameters of and 6, and the average phonon energies of and 470 cm−1 coupled with the electronic states could be reliably determined. Huayna Terraschke, Markus Suta, Matthias Adlung, Samira Mammadova, Nahida Musayeva, Rasim Jabbarov, Mihail Nazarov, and Claudia Wickleder Copyright © 2015 Huayna Terraschke et al. All rights reserved. Optical Transition Probabilities of Er3+ Ions in ErBa3B9O18 Crystal Sun, 22 Feb 2015 14:15:19 +0000 http://www.hindawi.com/journals/jspec/2015/871320/ The optical absorption and emission intensity of luminescent and birefringent crystal ErBa3B9O18 were examined from optical absorption data based on Judd-Ofelt theory. The three intensity parameters () are 3.10 × 10−20, 0.87 × 10−20, and 1.80 × 10−20 cm2, respectively. From the obtained intensity parameters, the radiative probabilities , radiative lifetime , fluorescence branching ratios , and integrated emission cross sections have been calculated. In comparison with other Er-doped luminescent crystals, ErBa3B9O18 may find application in thin disk laser. Ming He, Tiezheng Liu, Junling Xiu, Yuanguang Tang, and Zhihua Zhang Copyright © 2015 Ming He et al. All rights reserved. Mimicking Multimodal Contrast with Vertex Component Analysis of Hyperspectral CARS Images Sun, 22 Feb 2015 13:29:54 +0000 http://www.hindawi.com/journals/jspec/2015/575807/ We show the applicability of vertex component analysis (VCA) of hyperspectral CARS images in generating a similar contrast profile to that obtained in “multimodal imaging” that uses signals from three separate nonlinear optical techniques. Using an atherosclerotic rabbit aorta test image, we show that the VCA algorithm provides pseudocolor contrast that is comparable to multimodal imaging, thus suggesting that under certain conditions much of the information gleaned from a multimodal nonlinear optical approach can be sufficiently extracted from the CARS hyperspectral stack itself. This is useful for unsupervised contrast generation on hyperspectral CARS implementations such as multiplex CARS that may not have multimodal capabilities. The utility of VCA as a quantitative analysis tool in CARS is also addressed. Joel T. Tabarangao and Aaron D. Slepkov Copyright © 2015 Joel T. Tabarangao and Aaron D. Slepkov. All rights reserved. Intercomparison of Numerical Inversion Algorithms for Particle Size Determination of Polystyrene Suspensions Using Spectral Turbidimetry Sun, 22 Feb 2015 12:05:58 +0000 http://www.hindawi.com/journals/jspec/2015/645879/ The continuous monitoring of the particle size distribution in particulate processes with suspensions or emulsions requires measurement techniques that can be used as in situ devices in contrast to ex situ or laboratory methods. In this context, for the evaluation of turbidimetric spectral measurements, the application of different numerical inversion algorithms is investigated with respect to the particle size distribution determination of polystyrene suspensions. A modified regularization concept consisting of a Twomey-Phillips-Regularization with an integrated nonnegative constraint and a modified L-curve criterion for the selection of the regularization parameter is used. The particle size (i.e., particle diameter) of polystyrene suspensions in the range –3 µm was validated via dynamic light scattering and differential centrifugal sedimentation and compared to the retrieved particle size distribution from the inverted turbidimetry measurements. Benjamin Glasse, Norbert Riefler, and Udo Fritsching Copyright © 2015 Benjamin Glasse et al. All rights reserved. Changes of pH in β-Lactoglobulin and β-Casein Solutions during High Pressure Treatment Thu, 19 Feb 2015 12:58:02 +0000 http://www.hindawi.com/journals/jspec/2015/935901/ The pH changes in the milk systems, β-lactoglobulin B, β-casein, and mixture of β-lactoglobulin and β-casein (pH 7 and ionic strength 0.08 M) were measured in situ during increasing pressure up to 500 MPa. An initial decrease to pH 6.7 was observed from 0.1 to 150 MPa for β-lactoglobulin, followed by an increase to pH 7.3 at 500 MPa. The initial decrease is suggested to be caused by the deprotonation of histidine, while the increase is suggested to result from an increase of hydroxide ions due to the loss of tertiary structure. The change in pH of the β-casein solution displayed an almost linear increasing pressure dependency up to a pH of 7.7 at 500 MPa. The limited tertiary structure of β-casein could allow exposure of all amino acids; thus the increase of pH can be caused by binding of water protons resulting in an increase of hydroxide ions. Addition of β-casein to β-lactoglobulin (1:1) was found to suppress the initial pH decrease found for the β-lactoglobulin solution. The pH change of the mixture did not suggest any intermolecular interaction, and a simple additive model is proposed to calculate the pH change of the mixture from the corresponding individual samples. Karsten Olsen, Bo B. Jespersen, and Vibeke Orlien Copyright © 2015 Karsten Olsen et al. All rights reserved. The Use of ATR-FTIR Spectroscopy for Quantification of Adsorbed Compounds Wed, 18 Feb 2015 11:36:09 +0000 http://www.hindawi.com/journals/jspec/2015/727595/ Quantification of adsorbed amounts requires in most cases several assumptions. Adsorption of organic compounds, for example, is usually measured indirectly, by mass balance calculations based on the evaluation of the remaining chemical in solution. Such procedure might yield overestimates when precipitation or degradation of the adsorbate occurs and underestimates when separation of the sorbent material (e.g., clay particles) with the adsorbed chemical is not effective. This study presents a simple quantification procedure based on the ratio between IR absorption bands of the sorbate and the adsorbate. The advantages of the procedure are (a) direct evaluation of the adsorbed amount and (b) accurate measurement of chemicals that are hard to quantify, as those that do not absorb light in the UV-Visible range, or require expensive chromatography procedures. Giora Rytwo, Roee Zakai, and Bernd Wicklein Copyright © 2015 Giora Rytwo et al. All rights reserved. Raman Spectroscopy Study of the Doping Effect of the Encapsulated Iron, Cobalt, and Nickel Bromides on Single-Walled Carbon Nanotubes Wed, 18 Feb 2015 06:21:40 +0000 http://www.hindawi.com/journals/jspec/2015/653848/ In this contribution the modification of the electronic properties of single-walled carbon nanotubes (SWCNTs) filled with nickel bromide, cobalt bromide, and iron bromide was studied by Raman spectroscopy. The doping-induced alterations of the radial breathing mode (RBM) and G-mode in the Raman spectra of the filled SWCNTs were analyzed in detail. The observed shifts of the components of the Raman modes and changes of their profiles allowed concluding that the embedded compounds have an acceptor doping effect on the SWCNTs, and the doping level increases in the line with nickel bromide-cobalt bromide-iron bromide. Marianna V. Kharlamova Copyright © 2015 Marianna V. Kharlamova. All rights reserved. Infrared Absorption Spectroscopic Study on Reaction between Self-Assembled Monolayers and Atmospheric-Pressure Plasma Wed, 11 Feb 2015 10:18:21 +0000 http://www.hindawi.com/journals/jspec/2015/417024/ Plasma is becoming increasingly adopted in bioapplications such as plasma medicine and agriculture. This study investigates the interaction between plasma and molecules in living tissues, focusing on plasma-protein interactions. To this end, the reaction of air-pressure air plasma with NH2-terminated self-assembled monolayer is investigated by infrared spectroscopy in multiple internal reflection geometry. The atmospheric-pressure plasma decomposed the NH2 components, the characteristic units of proteins. The decomposition is attributed to water clusters generated in the plasma, indicating that protein decomposition by plasma requires humid air. Masanori Shinohara, Katsuhiro Amano, Naoki Maruno, Yuta Yoshida, Yoshinobu Matsuda, and Hiroshi Fujiyama Copyright © 2015 Masanori Shinohara et al. All rights reserved. Controlling Terahertz Surface Plasmon Properties on a Periodically Structured Silicon Surface Wed, 04 Feb 2015 13:45:59 +0000 http://www.hindawi.com/journals/jspec/2015/543985/ The paper presents experimental and numerical investigations on the terahertz (THz) surface plasmon propagation in a periodically patterned doped silicon substrate. Silicon substrates are periodically patterned with 2D array of vertical structures forming a plasmonic waveguide. The waveguide configurations are found to support resonant surface modes at certain frequencies which can occur anywhere depending on the structural parameters. The 2D pattern of vertical structures is observed to affect the THz surface plasmon propagation along the waveguide configuration. The periodicities are changed in both directions to examine the change in amplitude and cut-off frequencies of the resonant surface modes. The results are confirmed independently through finite element method based numerical simulations and compared with theory. The present study should find applications in facilitating the development of futuristic ultrahigh speed networks and devices operating at the terahertz frequencies. Gagan Kumar Copyright © 2015 Gagan Kumar. All rights reserved. Vibrational Spectroscopic Study of the Cocrystal Products Formed by Cinchona Alkaloids with 5-Nitrobarbituric Acid Sat, 31 Jan 2015 13:27:32 +0000 http://www.hindawi.com/journals/jspec/2015/340460/ X-ray powder diffraction, differential scanning calorimetry, infrared absorption spectroscopy, and Raman spectroscopy have been used to study the phenomenon of cocrystal formation in the molecular complexes formed by 5-nitrobarbituric acid with four cinchona alkaloids. The cocrystal products were found to contain varying degrees of hydration, ranging from no hydration in the nitrobarbiturate-quinidine cocrystal up to a 4.5-hydrate species in the nitrobarbiturate-cinchonine cocrystal. For the nitrobarbiturate cocrystals with cinchonine, cinchonidine, and quinidine, the predominant interaction was with the quinoline ring system of the alkaloid. However, for quinine, the predominant interaction was with the quinuclidine group of the alkaloid. These properties serve to demonstrate the utility of 5-nitrobarbituric acid as a preferred reagent for chemical microscopy, since the differing range of hydrate and structural types would serve to easily differentiate the cinchona alkaloids from each other, even when different compounds contained the same absolute configurations at their dissymmetric centers. Harry G. Brittain Copyright © 2015 Harry G. Brittain. All rights reserved. Electron Spin Resonance and Atomic Force Microscopy Study on Gadolinium Doped Ceria Thu, 29 Jan 2015 12:51:13 +0000 http://www.hindawi.com/journals/jspec/2015/491840/ A combined electron spin resonance (ESR) and atomic force microscopy (AFM) study on Ce1−xGdxO2−x/2 samples is here presented, aimed at investigating the evolution of the ESR spectral shape as a function of in a wide composition range. At low , the spectrum is composed of features at ; 2.8; 6. With increasing , this pattern merges into a single broad ESR curve, which assumes a Dysonian-shaped profile at , whereas, at these values, AFM measurements show an increasing surface roughness. It is suggested that the last could cause the formation of surface polaritons at the origin of the particular ESR spectral profile observed at these high Gd doping levels. Cesare Oliva, Francesco Orsini, Serena Cappelli, Paolo Arosio, Mattia Allieta, Mauro Coduri, and Marco Scavini Copyright © 2015 Cesare Oliva et al. All rights reserved. Study of the Synergistic Effect of Nanoporous Nickel Phosphates on Novel Intumescent Flame Retardant Polypropylene Composites Thu, 29 Jan 2015 06:26:48 +0000 http://www.hindawi.com/journals/jspec/2015/289298/ A char forming agent (CFA) and silica-gel microencapsulated ammonium polyphosphate (Si-MCAPP) were selected to form novel intumescent flame retardant system to prepare flame retardant polypropylene (PP) composites, and then the influences of nanoporous nickel phosphates (NiP) on the thermal and flame retardant properties of flame retardant PP composites were studied by the real time FTIR (RTFTIR) spectra, limited oxygen index (LOI) test, and the scanning electron microscopy. RTFTIR shows the addition of NiP can improve the thermal stability of flame retardant PP composites. LOI test shows LOI value is increased with the increase of the content of NiP, and the optimized concentration of NiP is 1.0%. Furthermore, smoke toxicity of the novel flame retardant PP composites was studied by mice experiment. The upper limit of the no death smoke concentration of the composite is 12.37 mg/L. Shibin Nie, Chi Zhang, Chao Peng, De-yi Wang, Daowei Ding, and Qingliang He Copyright © 2015 Shibin Nie et al. All rights reserved. Dictionary-Based, Clustered Sparse Representation for Hyperspectral Image Classification Thu, 22 Jan 2015 11:40:16 +0000 http://www.hindawi.com/journals/jspec/2015/678765/ This paper presents a new, dictionary-based method for hyperspectral image classification, which incorporates both spectral and contextual characteristics of a sample clustered to obtain a dictionary of each pixel. The resulting pixels display a common sparsity pattern in identical clustered groups. We calculated the image’s sparse coefficients using the dictionary approach, which generated the sparse representation features of the remote sensing images. The sparse coefficients are then used to classify the hyperspectral images via a linear SVM. Experiments show that our proposed method of dictionary-based, clustered sparse coefficients can create better representations of hyperspectral images, with a greater overall accuracy and a Kappa coefficient. Zhen-tao Qin, Wu-nian Yang, Ru Yang, Xiang-yu Zhao, and Teng-jiao Yang Copyright © 2015 Zhen-tao Qin et al. All rights reserved. Synthesis and Photocatalytic Activity of Mo-Doped TiO2 Nanoparticles Thu, 22 Jan 2015 08:08:03 +0000 http://www.hindawi.com/journals/jspec/2015/681850/ The undoped and Mo-doped TiO2 nanoparticles were synthesized by sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), diffuse reflectance UV-visible absorption spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), and transmission electron microscopy (TEM). The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue under irradiation of a 500 W xenon lamp and natural solar light outdoor. Effects of calcination temperatures and Mo doping amounts on crystal phase, crystallite size, lattice distortion, and optical properties were investigated. The results showed that most of Mo6+ took the place of Ti4+ in the crystal lattice of TiO2, which inhibited the growth of crystallite size, suppressed the transformation from anatase to rutile, and led to lattice distortion of TiO2. Mo doping narrowed the band gap (from 3.05 eV of TiO2 to 2.73 eV of TiMo0.02O) and efficiently increased the optical absorption in visible region. Mo doping was shown to be an efficient method for degradation of methylene blue under visible light, especially under solar light. When the calcination temperature was 550°C and the Mo doping amount was 2.0%, the Mo-doped TiO2 sample exhibited the highest photocatalytic activity. Ji-guo Huang, Xue-ting Guo, Bo Wang, Lin-yang Li, Mei-xia Zhao, Li-li Dong, Xing-juan Liu, and Yu-ting Huang Copyright © 2015 Ji-guo Huang et al. All rights reserved. Compression of Extreme-Ultraviolet Ultrashort Pulses by Grating Configurations Thu, 22 Jan 2015 06:46:51 +0000 http://www.hindawi.com/journals/jspec/2015/495914/ The design and realization of grating instruments to condition the spectral phase of ultrashort extreme-ultraviolet pulses are discussed. The main application of such configurations is the temporal compression of pulses by compensating the phase chirp and getting close to the Fourier limit. We discuss the two configurations useful for the realization of ultrafast grating compressors, namely, the classical diffraction mount and the off-plane one. The configuration may be applied to free-electron lasers and high-order laser harmonics. Fabio Frassetto, Paolo Miotti, and Luca Poletto Copyright © 2015 Fabio Frassetto et al. All rights reserved. Calibration Method for Confocal X-Ray Microanalysis with Polychromatic Excitation Tue, 13 Jan 2015 11:02:43 +0000 http://www.hindawi.com/journals/jspec/2015/368054/ To apply the fundamental parameters method at the confocal setup the knowledge of the sensitivity of the spectrometer is required which depends on the characteristics of two X-ray lenses: one in the excitation channel and another in the detection channel. For the particular case of polychromatic excitation, the theory shows that the focalization properties of the excitation lens for all incident energies affect the X-ray fluorescence intensity. Therefore the traditional calibration method based on the measurement of standard samples becomes unstable since the number of required fitting parameters is too high. To reduce these parameters a previous characterization of the excitation lens by a simulation program was employed giving rise to a simplified confocal setup calibration. The developed calibration method was applied for a confocal spectrometer implemented in the Brazilian Synchrotron Radiation Source (LNLS) with white beam. The experimental parameters of the sensitivity were obtained from depth profile analysis of several pure thin films. The calibrated confocal setup was used to quantify reference standards in order to validate the calibration procedure. Our results for elemental concentrations show relative errors less than 15% for the quantitative analysis of a light matrix reference standard. C. Sosa, V. Stoytschew, J. Leani, H. J. Sánchez, C. A. Pérez, and R. D. Perez Copyright © 2015 C. Sosa et al. All rights reserved. Analysis of 31 Hydrazones of Carbonyl Compounds by RRLC-UV and RRLC-MS(/MS): A Comparison of Methods Tue, 13 Jan 2015 09:38:17 +0000 http://www.hindawi.com/journals/jspec/2015/890836/ Aldehydes and ketones are volatile organic compounds (VOC) emitted into the atmosphere by a large number of natural and anthropogenic sources. Carbonyl compounds (CC) are atmospheric pollutants with known damaging effects for the human’s health. In this work, the separation of 31 carbonyl compounds (CC) in their 2,4-dinitrophenylhydrazones form was optimized by rapid resolution liquid chromatography in 9 minutes and simultaneously detected by ultraviolet and mass spectrometry with an APCI(−) as ionization source. The mass spectra of hydrazones presented the [M-H]− ions as base peak, but the MS/MS spectra showed fragments related to different structural classes of aldehydes and ketones, representing an important tool to assist structure elucidation of unknown CC in real samples. Multiple reactions monitoring (MRM) improved the sensitivity and selectivity for the quantitation method. Analytical parameters using both UV and MS (linearity, determination coefficients, detection limits, and sensitivity) were compared. The detection methods are complementary and a powerful analytical tool for the detection and quantitation of CC in complex environmental samples. Soraya de M. Ochs, Maíra Fasciotti, and Annibal D. Pereira Netto Copyright © 2015 Soraya de M. Ochs et al. All rights reserved. SERS Characterization of the Indocyanine-Type Dye IR-820 on Gold and Silver Nanoparticles in the Near Infrared Tue, 13 Jan 2015 07:53:16 +0000 http://www.hindawi.com/journals/jspec/2015/805649/ The Raman spectrum of the indocyanine-type dye IR-820 has been assigned for both solid and solution. SERS spectra of IR-820 on both silver and gold nanoparticles suspensions excited at 1064 nm were obtained. AgNPs allowed the detection of the dye through SERS down to 0.1 micromoles per liter; for the AuNPs the lowest concentration of the dye detectable was 10 micromoles per liter. Changes in the SERS relative intensities compared to the Raman spectrum in solution are subtle, mostly due to the preresonance effect of the dye. However, a perpendicular orientation relative to the metallic surface was inferred for the dye on both AgNPs and AuNPs. The easily distinguishable SERS spectra of the dye excited at 1064 nm, together with the high biological compatibility of cyanine dyes, are both indicative that IR-820 could be used as a high-performance probe molecule for SERS. Tatiana B. V. Neves and Gustavo F. S. Andrade Copyright © 2015 Tatiana B. V. Neves and Gustavo F. S. Andrade. All rights reserved. Structural and Spectroscopic Characterization of PM 597 Dye-Silica Core-Shell Nanoparticles Mon, 12 Jan 2015 12:48:14 +0000 http://www.hindawi.com/journals/jspec/2015/901032/ Nanostructured fluorescent pyrromethene (PM) doped-silica core-shell particles were successfully prepared by Stöber process. The average size of the particles was in the range of 10–20 nm measured by TEM micrograph. The atomic structure and morphology of PM 597/SiO2 core/shell nanoparticles were studied by AFM and SEM, respectively. Absorption and emission spectra of the PM 597/SiO2 core/shell nanoparticles under the UV irradiation were studied and not significantly influenced at the position of peaks. Finally, amplified spontaneous emission (ASE) and photobleaching of dye were examined and found no significant influence on the peaks of PM dye due to the formation of smaller sizes of PM 597/SiO2 core/shell nanoparticles. The observed PM 597/SiO2 core/shell nanoparticles were different in shapes with smaller size distribution and highly luminescent. Majority of nanoparticles were roughly spherical with many of them aggregated. The less photobleaching of dye core may be due to the protection of pumped energy by SiO2 shell and restricts the leakage of dye. Tahani R. Al-Biladi, A. S. Al Dwayyan, M. Naziruddin Khan, Saif M. H. Qaid, and Khalid Al Zahrani Copyright © 2015 Tahani R. Al-Biladi et al. All rights reserved. Pencil Beam Spectral Measurements of Ce, Ho, Yb, and Ba Powders for Potential Use in Medical Applications Tue, 06 Jan 2015 05:59:46 +0000 http://www.hindawi.com/journals/jspec/2015/563763/ The aim of the present study was to obtain modified X-ray spectra, by using appropriate filter materials for use in applications such as dual energy X-ray imaging. K-edge filtering technique was implemented in order to obtain narrow energy bands for both dual- and single-kVp techniques. Three lanthanide filters (cerium, holmium, and ytterbium) and a filter outside lanthanides (barium), with low K-edge, were used to modify the X-ray spectra. The X-ray energies that were used in this work ranged from 60 to 100 kVp. Relative root mean square error (RMSE) and the coefficient of variation were used for filter selection. The increasing filter thicknesses led to narrower energy bands. For the dual-kVp technique, 0.7916 g/cm2 Ho, 0.9422 g/cm2 Yb, and 1.0095 g/cm2 Yb were selected for 70, 80, and 90 kVp, respectively. For the single-kVp technique 0.5991 g/cm2 Ce, 0.8750 g/cm2 Ba, and 0.8654 g/cm2 Ce were selected for 80, 90, and 100 kVp, respectively. The filtered X-ray spectra of this work, after appropriate modification, could be used in various X-ray applications, such as dual-energy mammography, bone absorptiometry, and digital tomosynthesis. N. Martini, V. Koukou, C. Michail, P. Sotiropoulou, N. Kalyvas, I. Kandarakis, G. Nikiforidis, and G. Fountos Copyright © 2015 N. Martini et al. All rights reserved. Effect of Sintering Temperature on Structural and Morphological Properties of Europium (III) Oxide Doped Willemite Wed, 31 Dec 2014 12:06:12 +0000 http://www.hindawi.com/journals/jspec/2014/328931/ Willemite- (Zn2SiO4-) based glass ceramics doped with various amounts of europium oxide (Eu2O3) were prepared by solid state melting and quenching method. Effect of sintering temperature (600–1000°C) on structural and morphological properties of the doped samples was investigated. Phase composition, phase evolution, functional groups, and microstructure analysis were, respectively, characterized using X-ray diffractometer (XRD), fourier transform infrared spectroscopy, field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray. XRD analysis detected the presence of rhombohedral crystalline phase in the doped samples sintered at different temperatures. FE-SEM and bulk density results confirmed that doping of the willemite with Eu2O3 effectively enhanced densification. The microstructural analysis of the doped samples showed that the average grain size increased with the increase of sintering temperature. Nur Fatin Syamimi, Khamirul Amin Matori, Way Foong Lim, Sidek Abdul Aziz, and Mohd Hafiz Mohd Zaid Copyright © 2014 Nur Fatin Syamimi et al. All rights reserved. In Situ Dispersive EXAFS in Electrocatalysis: The Investigation of the Local Structure of IrOx in Chronoamperometric Conditions as a Case Study Wed, 31 Dec 2014 11:56:18 +0000 http://www.hindawi.com/journals/jspec/2014/480102/ An in situ study with dispersive EXAFS (Extended X-Ray Absorption Spectroscopy) at the Ir- edge is performed to characterize Electrodeposited Iridium Oxide Films (EIROF) under chronoamperometric conditions. The technique monitors the local chemical environment and electronic structure of iridium during the oxidation of Ir(III) to Ir(IV) with a time resolution of milliseconds. The study is performed in both acidic and basic media. The Fourier transforms of the time-resolved EXAFS signals clearly show that the short-range structure of Ir is similar to that of rutile-type IrO2 and is maintained during the reaction, thus accounting for the flexibility of the structure of the electrode material in accommodating different oxidation states. From a more general point of view, the work demonstrates the capabilities of in situ experiments based on state-of-the-art dispersive EXAFS in clarifying the mechanistic aspects of electrochemical processes. Elisabetta Achilli, Alessandro Minguzzi, Ottavio Lugaresi, Cristina Locatelli, Sandra Rondinini, Giorgio Spinolo, and Paolo Ghigna Copyright © 2014 Elisabetta Achilli et al. All rights reserved. Raman Study on Pompeii Potteries: The Role of Calcium Hydroxide on the Surface Treatment Wed, 31 Dec 2014 08:42:22 +0000 http://www.hindawi.com/journals/jspec/2014/435026/ Pottery samples from the Pompeii archaeological site were investigated by IR Raman spectroscopy and EDAX measurements. The analysis of the Raman spectra of the surfaces reveals the presence calcium hydroxide (peak at about 780 cm−1) while the calcium carbonate is totally absent. The comparative studies on the carbonation effect of the surfaces were performed on laboratory grown samples of calcium hydroxide. The samples were treated at high temperature and exposed to different ambient conditions, and the analysis suggests that the original surfaces of Roman pottery were scattered by calcium hydroxide (limewash) before the cooking process in the furnace. The result of this surface treatment not only permits a vitrification of the surfaces but also seems to reduce the content of CO2 in the furnace atmosphere and then obtain a more oxidant ambient during the cooking of the pottery. These results give new insights on the real degree of knowledge of the Romans about the art of ceramics and more generally about chemistry and technologies. Daniele Chiriu, Pier Carlo Ricci, Andrea Polcaro, Paolo Braconi, David Lanzi, and Davide Nadali Copyright © 2014 Daniele Chiriu et al. All rights reserved. Velocity Selective Polarization Spectroscopy for Modulation-Free Dispersion Signals at Detuned Frequencies Tue, 30 Dec 2014 09:16:31 +0000 http://www.hindawi.com/journals/jspec/2014/541063/ We present a simple technique to obtain modulation-free locking signals at the detuned frequency from an atom transition between hyperfine structures. Polarization spectroscopy allows us to obtain the dispersion signals that are suitable for frequency locking. Velocity selective optical pumping using another laser beam also allows us to obtain signals at the detuned frequency and to shift crossover signal away. By combining these two techniques, we were able to obtain the velocity selective birefringence signal only at the principle transition in an Rb vapor cell and compare the birefringence signal with the theoretical spectrum predicted by using Nakayama’s model. Hoon Yu, Seung Jin Kim, and Jung Bog Kim Copyright © 2014 Hoon Yu et al. All rights reserved.