Journal of Spectroscopy http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. A Review of Spectral Methods for Dispersion Characterization of Carbon Nanotubes in Aqueous Suspensions Sun, 28 Jun 2015 14:38:26 +0000 http://www.hindawi.com/journals/jspec/2015/463156/ Characterization is a crucial step in the study of properties of nanomaterials to evaluate their full potential in applications. Carbon nanotube-based materials have properties that are sensitive to size, shape, concentration, and agglomeration state. It is therefore critical to quantitatively characterize these factors in situ, while the processing takes place. Traditional characterization techniques that rely on microscopy are often time consuming and in most cases provide qualitative results. Spectroscopy has been studied as an alternative tool for identifying, characterizing, and studying these materials in situ and in a quantitative way. In this paper, we provide a critical review of the spectroscopy techniques used to explore the surface properties (e.g., dispersion) characteristics of carbon nanotubes in aqueous suspensions during the sonication process. Jidraph Njuguna, O. Arda Vanli, and Richard Liang Copyright © 2015 Jidraph Njuguna et al. All rights reserved. Identification and Disease Index Inversion of Wheat Stripe Rust and Wheat Leaf Rust Based on Hyperspectral Data at Canopy Level Sun, 28 Jun 2015 14:10:43 +0000 http://www.hindawi.com/journals/jspec/2015/651810/ Stripe rust and leaf rust with similar symptoms are two important wheat diseases. In this study, to investigate a method to identify and assess the two diseases, the canopy hyperspectral data of healthy wheat, wheat in incubation period, and wheat in diseased period of the diseases were collected, respectively. After data preprocessing, three support vector machine (SVM) models for disease identification and six support vector regression (SVR) models for disease index (DI) inversion were built. The results showed that the SVM model based on wavelet packet decomposition coefficients with the overall identification accuracy of the training set equal to 99.67% and that of the testing set equal to 82.00% was better than the other two models. To improve the identification accuracy, it was suggested that a combination model could be constructed with one SVM model and two models built using K-nearest neighbors (KNN) method. Using the DI inversion SVR models, the satisfactory results were obtained for the two diseases. The results demonstrated that identification and DI inversion of stripe rust and leaf rust can be implemented based on hyperspectral data at the canopy level. Hui Wang, Feng Qin, Qi Liu, Liu Ruan, Rui Wang, Zhanhong Ma, Xiaolong Li, Pei Cheng, and Haiguang Wang Copyright © 2015 Hui Wang et al. All rights reserved. Broadband Spectroscopic Thermoacoustic Characterization of Single-Walled Carbon Nanotubes Mon, 15 Jun 2015 06:45:11 +0000 http://www.hindawi.com/journals/jspec/2015/762352/ Carbon nanotubes have attracted interest as contrast agents for biomedical imaging because they strongly absorb electromagnetic radiation in the optical and microwave regions. This study applies thermoacoustic (TA) imaging and spectroscopy to measure the frequency-dependent absorption profile of single-walled carbon nanotubes (SWNT) in the ranges of 2.7–3.1 GHz and 7–9 GHz using two tunable microwave sources. Between 7 and 9 GHz, the peak TA signal for solutions containing semiconducting and metallic SWNTs increased monotonically with a slope of 1.75 AU/GHz () and 2.8 AU/GHz (), respectively, relative to a water baseline. However, after compensating for the background signal from water, it was revealed that the TA signal from metallic SWNTs increased exponentially within this frequency band. Results suggest that TA imaging and spectroscopy could be a powerful tool for quantifying the absorption properties of SWNTs and optimizing their performance as contrast agents for imaging or heat sources for thermal therapy. Daniel R. Bauer, Xiong Wang, Jeff Vollin, Hao Xin, and Russell S. Witte Copyright © 2015 Daniel R. Bauer et al. All rights reserved. Nondestructive Detection of Blackheart in Potato by Visible/Near Infrared Transmittance Spectroscopy Sun, 14 Jun 2015 12:39:08 +0000 http://www.hindawi.com/journals/jspec/2015/786709/ The possibility of using visible/near infrared (Vis/NIR) transmission spectroscopic technique in the 513–850 nm region coupled with partial least squares-linear discriminant analysis (PLS-LDA) and other chemometric methods to classify potatoes with blackheart was investigated. The discrimination performance of different morphological correction methods, including weight correction, height correction, and volume correction, was compared. The results showed that height corrected transmittance has the best performance, with both calibration and validation sets having a success rate of 97.11%. Out of 1800 wavelengths, only six wavelengths (711, 817, 741, 839, 678, and 698 nm) were selected as the optimum wavelengths for the discrimination of blackheart tubers based on principal component analysis (PCA). The data analysis showed that the overall classification rate by PLS-LDA method decreased from 97.11% to 96.82% in calibration set and from 97.11% to 96.53% in validation set, which was acceptable. The importance of these conclusions may be helpful to transfer Vis/NIR transmission technology from laboratory to industrial application in nondestructive, real-time, or portable measurement of potatoes quality. Zhu Zhou, Songwei Zeng, Xiaoyu Li, and Jian Zheng Copyright © 2015 Zhu Zhou et al. All rights reserved. Discriminating the Geographical Origins of Chinese White Lotus Seeds by Near-Infrared Spectroscopy and Chemometrics Wed, 10 Jun 2015 12:40:30 +0000 http://www.hindawi.com/journals/jspec/2015/831246/ The traceability of a Chinese white lotus seed (WLS) with Protected Designation of Origin (PDO) was investigated using near-infrared (NIR) spectroscopy and chemometrics. Three chemometrics methods, discrimination analysis (DA), class modeling, and a newly proposed strategy, the fusion of DA and class modeling, were investigated to compare their capacity to trace the geographical origins of WLS. Least squares support vector machine (LS-SVM) was developed to distinguish the PDO WLS from non-PDO WLS of four main producing areas. A class modeling technique, one-class partial least squares (OCPLS), was developed only using the data of PDO WLS. By the fusion of LS-SVM and OCPLS, the best prediction sensitivity and specificity were 0.900 and 0.973, respectively. The results indicate that fusion of DA and class modeling can enhance the specificity for detection of non-PDO products. The conclusion is that DA and class modeling should be combined for tracing food geographical origins. Lu Xu, Chen-Bo Cai, Yuan-Bin She, and Li-Juan Chen Copyright © 2015 Lu Xu et al. All rights reserved. Spectroscopic Studies of the Behavior of Eu3+ on the Luminescence of Cadmium Tellurite Glasses Sun, 07 Jun 2015 07:40:08 +0000 http://www.hindawi.com/journals/jspec/2015/478329/ The effect of europium doping on the photoluminescence of ZnO-CdO-TeO2 glasses is analyzed. TeO2-based glasses are of high interest as hosts for laser glasses. The Eu-doped oxide glasses were prepared by the conventional melt-quenching method. Five different concentrations of europium nitrate hexahydrate that varied from 0.3 to 1.5 mol% were used. SEM observations revealed the formation of zinc aluminate spinel and disperse droplets of liquid-liquid phase separation in the glasses. X-Ray diffraction reveals the amorphous structure of the fabricated glasses. FT-IR and Raman spectra show the presence of TeO4 and TeO3+1/TeO3 units that conform with the glass matrix. Raman spectra evidenced a band located at 1556 cm−1 that can be related to interstitial molecular oxygen in the glass matrix. Photoluminescence of the glasses showed light emission due to the following europiumtransitions from its , , and levels to its manifolds: (468 nm), (490 nm), (511 nm), (536 nm), (554 nm), (579.5 nm), (592 nm), (613 nm), (652 nm), and (490 nm). The estimated decay time, , was 0.4 ms for all the glasses. I. V. García-Amaya, Ma. E. Zayas, J. Alvarado-Rivera, E. Álvarez, S. A. Gallardo-Heredia, G. A. Limón, R. Lozada-Morales, and J. Ma. Rincón Copyright © 2015 I. V. García-Amaya et al. All rights reserved. Position, Energy, and Transit Time Distributions in a Hemispherical Deflector Analyzer with Position Sensitive Detector Mon, 01 Jun 2015 08:33:21 +0000 http://www.hindawi.com/journals/jspec/2015/153513/ Practical analytic equations, for the ideal field, and numerical results from SIMION simulations, for the fringing field, are presented for the exit radius and transit time of electrons in a hemispherical deflector analyzer (HDA) over a wide range of analyzer parameters. Results are presented for a typically dimensioned HDA with mean radius  mm and interradial separation  mm able to accommodate a 40 mm diameter position sensitive detector (PSD). Results for three different entry positions are compared: (the conventional central entry) and two displaced (paracentric) entries:  mm and  mm. Exit spreads , and base energy resolution are computed for HDA pass energies , 100, 500, and 1000 eV, entry aperture sizes  mm, entry angular spreads °, and an electron beam with relative energy spread . Overall, under realistic conditions, both paracentric entries demonstrate near ideal field behavior and clear superiority over the conventional entry at . The  mm entry has better absolute energy and time spread resolutions, while the  mm has better relative energy resolutions, both offering attractive alternatives for time-of-flight and coincidence applications where both energy and timing resolutions are important. Omer Sise and Theo J. M. Zouros Copyright © 2015 Omer Sise and Theo J. M. Zouros. All rights reserved. Influence of Erbium Ions on the Optical and Structural Properties of Polyvinyl Alcohol Wed, 27 May 2015 10:14:33 +0000 http://www.hindawi.com/journals/jspec/2015/204867/ Polyvinyl alcohol (PVA) films doped with erbium chloride (ErCl3) have been prepared by casting from their aqueous solutions. The structure of the doped samples as well as the interactions between the host PVA and Er+3 was investigated using FTIR spectroscopy. The optical measurement was recorded at room temperature in the range from 200 nm to 2000 nm. FTIR measurements revealed that Er+3 forms complex configuration within the PVA structure. PVA doped with 9 wt% of ErCl3 exhibits energy gap and refractive index of 5.1 eV and 1.72, respectively. The effect of the doping increment of ErCl3 on the optical parameters has been discussed. Taymour A. Hamdalla, Taha A. Hanafy, and Ashraf E. Bekheet Copyright © 2015 Taymour A. Hamdalla et al. All rights reserved. Spectroscopic Evaluations of Interfacial Oxidative Stability of Phosphonic Nanocoatings on Magnesium Mon, 18 May 2015 12:46:15 +0000 http://www.hindawi.com/journals/jspec/2015/350630/ Magnesium (Mg), and its alloys, is being investigated for its potential biomedical applications for its use as a biodegradable metal. However surface modification strategies are needed to modify the surface of the Mg alloy for its applicability in these applications. Self-assembled monolayers (SAMs) have been investigated as a coating strategy on magnesium for biomedical applications. In this report we evaluate the oxidative interfacial stability of phosphonic nanocoatings on magnesium using spectroscopic techniques. Self-assembled mono-/multilayers (SAMs) of octadecylphosphonic acid (ODPA) were formed on the native oxide layer of magnesium alloy using solution deposition technique. The SAMs modified Mg alloy and its oxidative stability were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). FTIR studies indicated mono-/bidentate bonding of the phosphonic SAMs to the Mg alloy surface. XPS confirmed SAM formation showing presence of “P” peaks while consequently showing decrease in peak intensity of Mg peaks. XPS analysis of the phosphonate peaks showed consistent presence of this peak over a period of 21 days. AFM images showed consistent coverage of the Mg alloy over a period of 21 days. The results collectively confirm that the monolayers are stable under the chosen oxidative study. Anil Mahapatro, Taína D. Matos Negrón, and Alan Nguyen Copyright © 2015 Anil Mahapatro et al. All rights reserved. Tuning the Refractive Index and Optical Band Gap of Silk Fibroin Films by Electron Irradiation Sun, 17 May 2015 10:57:44 +0000 http://www.hindawi.com/journals/jspec/2015/879296/ The Bombyx mori silk fibroin (SF) films were prepared by solution casting method and effects of electron beam on the optical properties and optical constants of the films have been studied by using UV-Visible spectrophotometer. Optical properties like optical band gap , refractive index n, extinction coefficient k, optical conductivity , and dielectric constants of virgin and electron irradiated films were determined by using UV-Visible absorption and transmission spectra. It was found that the reduction in optical band gap and increase in refractive index with increasing radiation dosage was observed. It is also observed from results that there is increase in dielectric constants with increasing photon energy. The observed optical changes have been tried to be correlated with the structural changes, revealed through FT-IR spectroscopy. The present study is quite important for tailoring the optical responses of SF films as per specific requirements. S. Asha, Y. Sangappa, and Sanjeev Ganesh Copyright © 2015 S. Asha et al. All rights reserved. A Model System for Concurrent Detection of Antigen and Antibody Based on Immunological Fluorescent Method Mon, 11 May 2015 13:44:54 +0000 http://www.hindawi.com/journals/jspec/2015/248504/ This paper describes a combined antigen/antibody immunoassay implemented in a 96-well plate using fluorescent spectroscopic method. First, goat anti-human IgG was used to capture human IgG (model antigen); goat anti-human IgG (Cy3 or FITC) was used to detect the model antigen; a saturating level of model antigen was then added followed by unlabelled goat anti-human IgG (model antibody); finally, Cy3 labelled rabbit anti-goat IgG was used to detect the model antibody. Two approaches were applied to the concomitant assay to analyze the feasibility. The first approach applied FITC and Cy3 when both targets were present at the same time, resulting in 50 ng/mL of the antibody detection limit and 10 ng/mL of antigen detection limit in the quantitative measurements of target concentration, taking the consideration of FRET efficiency of 68% between donor and acceptor. The sequential approach tended to lower the signal/noise (S/N) ratio and the detection of the model antigen (lower than 1 ng/mL) had better sensitivity than the model antibody (lower than 50 ng/mL). This combined antigen/antibody method might be useful for combined detection of antigens and antibodies. It will be helpful to screen for both antigen and antibody particularly in the situations of the multiserotype and high-frequency mutant virus infections. Yuan-Cheng Cao Copyright © 2015 Yuan-Cheng Cao. All rights reserved. Raman and Fluorescence Spectroscopy of CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7 Thu, 07 May 2015 13:52:43 +0000 http://www.hindawi.com/journals/jspec/2015/940172/ To better understand and ascertain the mechanisms of flotation reagent interaction with rare earth (RE) minerals, it is necessary to determine the physical and chemical properties of the constituent components. Seven rare earth oxides (CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7) that cover the rare earth elements (REEs) from light to heavy REEs have been investigated using Raman spectroscopy. Multiple laser sources (wavelengths of 325 nm, 442 nm, 514 nm, and 632.8 nm) for the Raman shift ranges from 100 cm−1 to 5000 cm−1 of these excitations were used for each individual rare earth oxide. Raman shifts and fluorescence emission have been identified. Theoretical energy levels for Er, Nd, and Yb were used for the interpretation of fluorescence emission. The experimental results showed good agreement with the theoretical calculation for Er2O3 and Nd2O3. Additional fluorescence emission was observed with Yb2O3 that did not fit the reported energy level diagram. Tb4O7 was observed undergoing laser induced changes during examination. Jianlan Cui and Gregory A. Hope Copyright © 2015 Jianlan Cui and Gregory A. Hope. All rights reserved. ZnO/ZnAl2O4 Nanocomposite Films Studied by X-Ray Diffraction, FTIR, and X-Ray Photoelectron Spectroscopy Tue, 28 Apr 2015 09:16:35 +0000 http://www.hindawi.com/journals/jspec/2015/836859/ ZnO/ZnAl2O4 nanocomposite films were synthesised by ultrasonic spray pyrolysis (USP) by extracting Al2O(SO4)2 oxide with zinc chloride hydrate in deionised water. The sample was then subjected to heat treatment at 650°C and 700°C for 1 h, which led to the formation of the spinel oxide (ZnAl2O4) and wurtzite (ZnO) phases. Al2(SO4)3·18H2O salt was transformed into aluminum oxide sulfate Al2O(SO4)2, which is an intermediary decomposition product, by calcination at 795°C for 3 h. The structures of the synthesised ZnO/ZnAl2O4 films were confirmed by XRD, FTIR, and X-ray photoelectron spectroscopy (XPS). XPS spectra of the major Zn, Al, and O photoelectron lines and the major X-ray induced Zn LMM Auger lines for ZnO/ZnAl2O4 are presented. S. Iaiche and A. Djelloul Copyright © 2015 S. Iaiche and A. Djelloul. All rights reserved. An Adaptive PHD Filter for Multitarget Tracking with Multispectral Data Fusion Mon, 20 Apr 2015 13:22:26 +0000 http://www.hindawi.com/journals/jspec/2015/179039/ In order to improve the detection and tracking performance of multiple targets from IR multispectral image sequences, the approach based on spectral fusion algorithm and adaptive probability hypothesis density (PHD) filter is proposed. Firstly, the nonstationary adaptive suppression method is proposed to remove the background clutter. Based on the multispectral image sequence, the spectral fusion method is used to detect the abnormal targets. Spectral fusion produces the appropriate binary detection model and the computational probability of detection. Secondly, the particle filtering-based adaptive PHD algorithm is developed to detect and track multiple targets. This algorithm can deal with the nonlinear measurement on target state. In addition, the calculated probability of detection substitutes the fixed detection probability in PHD filter. Finally, the synthetic data sets based on various actual background images were utilized to validate the effectiveness of the detection approach. The results demonstrate that the proposed approach outperforms the conventional sequential PHD filtering in terms of detection and tracking performances. Guoliang Zhang, Chunling Yang, and Yan Zhang Copyright © 2015 Guoliang Zhang et al. All rights reserved. Corrosion Performance of AISI-309 Exposed to Molten Salts V2O5-Na2SO4 at 700°C Applying EIS and Electrochemical Techniques Tue, 14 Apr 2015 11:05:55 +0000 http://www.hindawi.com/journals/jspec/2015/826759/ The corrosion performance of AISI-309 exposed 5 days to molten salts 50 mol% V2O5-50 mol% Na2SO4 at 700°C is reported in this paper. Such evaluation was made using three electrochemical techniques: potentiodynamic polarization curve (), electrochemical impedance spectroscopy (EIS), and linear polarization resistance (). From , the Tafel slopes, , and were obtained. From Nyquist and Bode plots, it was possible to determine two different stages; the first one showed just one loop, which indicated the initial formation of Cr2O3 layer over the metallic surface; after that, the dissolution of Cr2O3 formed a porous layer, which became part of the corrosion products; at the same time a NiO layer combined with sulfur was forming, which was suggested as the second stage, represented by two capacitive loops. EIS plots were in agreement with the physical characterization made from SEM and EDS analyses. Fitting of EIS experimental data allowed us to propose two electrical circuits, being in concordance with the corrosion stages. Parameters obtained from the simulation of EIS data are also reported. From the results, it was stated that AISI-309 suffered intergranular corrosion due to the presence of sulfur, which diffused to the metallic surface through a porous Cr2O3 layer. E. F. Diaz, C. Cuevas-Arteaga, N. Flores-García, S. Mejía Sintillo, and O. Sotelo-Mazón Copyright © 2015 E. F. Diaz et al. All rights reserved. On the Structural Analysis of -Ray Induced Primary Free Radicals in UHMWPE and Vitamin E Stabilized UHMWPE by ESR Spectroscopy Sun, 05 Apr 2015 11:29:15 +0000 http://www.hindawi.com/journals/jspec/2015/653853/ Oriented allyl radicals are detected at room temperature in gamma irradiated UHMWPE. The effects of vitamin E and storage at room temperature on this oriented structure are also investigated during the study. While testing powder as well as compression-molded solids, with or without vitamin E, a typical ESR spectrum was recorded at room temperature following 100 kGy gamma dose and subsequent storage at −78.5°C for one year. The simulated results show that the relative abundance of 5% alkyl, 68% allyl, and 27% polyenyl produced a 98.7% best fit of experimental ones. Furthermore, the allyl radical signal gives approximately 20% of random orientations and 80% of oriented molecules. In oriented PE, measured at −196°C, Ohnishi et al. (1916) observed 25 lines within a total magnetic field width of approximately 133 G. Our spectra also show 25 lines spread over 136 G in UHMWPE powder samples and at room temperature after one year of storage. Malik Sajjad Mehmood, Muhammad Shah Jahan, Tariq Yasin, Muhammad Tariq, Mohammad Ahmad Choudhry, and Masroor Ikram Copyright © 2015 Malik Sajjad Mehmood et al. All rights reserved. GC-FID and NMR Spectroscopic Studies on Gamma Irradiated Walnut Lipids Tue, 31 Mar 2015 14:30:54 +0000 http://www.hindawi.com/journals/jspec/2015/532762/ Walnuts have an excellent fatty acid profile, beneficial for coronary heart diseases. A diet rich in walnuts has shown to decrease the total and LDL cholesterol levels as well as lipoprotein levels. In this study, the effects of different doses of γ-irradiation and different packaging conditions on proximate composition and fatty acid profile of walnuts (Juglans regia L.) were investigated merging data from different spectroscopic techniques. Walnuts moisture, ash, fat, and protein content as well as fatty acid profile were evaluated immediately after irradiation. GC-FID results showed that SFA increased and MUFA and PUFA decreased with the increase of irradiation dose. Moreover, MUFA/SFA and PUFA/SFA ratios decreased compared to control samples. Furthermore, NMR spectroscopy was implemented to examine possible discrimination patterns based on irradiation dose and packaging. This approach revealed the role of PUFA decrease with the parallel increase of irradiation dose while indicating the protective role of vacuum and MAP compared to air packaging. In conclusion, at irradiation doses of up to 5 kGy, the walnuts retained the nutritional benefits of its fatty acids, in particular MUFA and PUFA. Concerning the different types of packaging, greater stability in the nuts was observed using MAP packaging. Vassilia J. Sinanoglou, Irini F. Strati, Katerina Kokkotou, Dimitra Lantzouraki, Constantinos Makris, and Panagiotis Zoumpoulakis Copyright © 2015 Vassilia J. Sinanoglou et al. All rights reserved. Effect of Salicylic Acid and 5-Sulfosalicylic Acid on UV-Vis Spectroscopic Characteristics, Morphology, and Contact Angles of Spin Coated Polyaniline and Poly(4-aminodiphenylaniline) Thin Films Tue, 31 Mar 2015 05:57:11 +0000 http://www.hindawi.com/journals/jspec/2015/609175/ Polyaniline and poly(4-aminodiphenyl)aniline have been prepared following two different synthetic protocols (a traditional method and a “green” method). Both the polymers have been spin coated with salicylic acid and 5-sulfosalicylic acid as the dopants, in order to obtain them in form of thin films. These materials have been characterized, thereof achieving important information on their water contact angles and surface morphology. A. Sironi, D. Marinotto, C. Riccardi, S. Zanini, E. Guerrini, C. Della Pina, and E. Falletta Copyright © 2015 A. Sironi et al. All rights reserved. Using Fourier Transform Infrared Spectroscopy to Study Effects of Magnetic Field Treatment on Wheat (Triticum aestivum L.) Seedlings Mon, 30 Mar 2015 11:27:23 +0000 http://www.hindawi.com/journals/jspec/2015/570190/ Magnetic field treatments have been utilized to promote germination and growth of a variety of species of plants; however the mechanism of concern has not been fully elucidated. In this research, wheat seedlings were treated with 500 mT and 1500 mT static magnetic field (SMF) for 10 and 20 min, respectively. Analyzing Fourier transform infrared spectra collected from leaves of seedlings showed that SMF treatments decreased the contents of lipids and proteins, shifted bands to higher wavenumbers in 3000–2800 cm−1 regions, and increased the ratio of CH2/CH3 which likely indicates a structural variation of lipids. For bands assigned to different second structures of proteins, slight bands shifting and changing the ratio of different second structures of proteins were observed due to SMF treatments. To summarize, the results revealed that lipids rather than proteins were sensitive to SMF treatments. The results provided insight into the SMF induced conformational changes of lipids and proteins in wheat leaves, which will help elucidate the biological mechanisms of SMF on plant growth and development. Zhenlin Wei, Dejie Jiao, and Junxiao Xu Copyright © 2015 Zhenlin Wei et al. All rights reserved. Spectroscopy Applied to Engineering Materials Thu, 26 Mar 2015 07:32:56 +0000 http://www.hindawi.com/journals/jspec/2015/693276/ Ming-Guo Ma, Wen Zeng, Shao-Wen Cao, Zhong-Chang Wang, and Jie-Fang Zhu Copyright © 2015 Ming-Guo Ma et al. All rights reserved. XPS, FTIR, EDX, and XRD Analysis of Al2O3 Scales Grown on PM2000 Alloy Wed, 25 Mar 2015 11:38:12 +0000 http://www.hindawi.com/journals/jspec/2015/868109/ This work is an original example to compare the results obtained after calcination of Al2O3 hydroxides and oxidation of alumino-formers alloys. FTIR and XPS signatures were obtained for various oxidation temperatures and compared with those known from the literature about calcination of Al2O3 precursors. The aim of this work is to evaluate the use of IR spectroscopy and XPS analysis to probe the structural varieties of Al2O3. For this objective, a study of the PM2000 oxidation at various temperatures was conducted by means of XRD, IR spectroscopy, XPS analysis, EDX analysis, and SEM observations. This allowed us to clearly differentiate the transition Al2O3 from the α-Al2O3 and, amongst the transition Al2O3, to differentiate the characteristic of the IR spectrum of γ-δ phases from that of the θ phase. K. Djebaili, Z. Mekhalif, A. Boumaza, and A. Djelloul Copyright © 2015 K. Djebaili et al. All rights reserved. Atomic Force Microscopy for Understanding Solvent Cointercalation into Graphite Electrode in Lithium Secondary Batteries Wed, 25 Mar 2015 08:38:41 +0000 http://www.hindawi.com/journals/jspec/2015/462140/ The electrochemical processes occurring at the surface of a highly ordered pyrolytic graphite (HOPG) electrode were investigated by in situ atomic force microscopy (AFM) to understand the solvent cointercalation involved in the formation of a surface film. AFM images were recorded under the conditions that AFM probe does not affect the electrode reaction. The AFM images show the morphological changes occurring at the electrode surface, indicating that two different types of reactions occurred in the film formation at the surface of the electrode. The formation of a blister structure was observed on the graphite surface, because of the decomposition of solvated lithium ions produced in the electrolyte solution and intercalation between the graphite layer and particulate materials. The solvent cointercalation reaction leading to the blister structure was more pronounced for the HOPG electrode with a higher value of mosaic spread. Yang-Soo Kim and Soon-Ki Jeong Copyright © 2015 Yang-Soo Kim and Soon-Ki Jeong. All rights reserved. The Improvement Effect of Dispersant in Fluorite Flotation: Determination by the Analysis of XRD and FESEM-EDX Wed, 25 Mar 2015 08:07:36 +0000 http://www.hindawi.com/journals/jspec/2015/859365/ Different dispersants were added in the dispersion process to improve the efficiency of fluorite flotation. The types and dosage of dispersant on the improvement of fluorite flotation were investigated; when the sodium polyacrylate (SPA) was used as the dispersant and its addition is 0.5%, the concentrate grade of CaF2 increased from 90% to 98% and the fluorite recovery increased from 81% to 85%. Methods of X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), and Energy dispersive X-ray spectrometer (EDX) were used to characterize the sample. According to the analysis of results, the optimal sample consisted of CaF2 and very little CaCO3 in the size range of 0–5 μm. It could be concluded that the mechanism of improvement for the concentrate grade and recovery of CaF2 was attributed to the change of potential energy barrier which caused the separation of particles with different charge. All results indicate that SPA has a great potential to be an efficient and cost-effective dispersant for the improvement of fluorite flotation. Y. J. Li, F. Y. Sun, Y. Zhou, and L. Zeng Copyright © 2015 Y. J. Li et al. All rights reserved. EPR Spectroscopy Investigation of Cu2+ Ions Adsorbed in Tannin-Formaldehyde Resins of Mimosa (Acacia mearnsii) Bark Extracts Tue, 24 Mar 2015 13:46:29 +0000 http://www.hindawi.com/journals/jspec/2015/978270/ The chemical environment of Cu2+ ions adsorbed in tannin-formaldehyde resins of Acacia mearnsii bark extracts, prepared from polybutene, is investigated by EPR spectroscopy at 300 K. The spectrum is simulated considering two isolated axial Cu(II) species (Species 1: , , , and ; Species 2: , , , and ), superposed to a broad line (; linewidth = 30.0(5) mT) assigned to Cu(II) aggregates. Measurements at 77 K did not improve spectral resolution. Heating at 413 K changes the hyperfine parameters of Species 2 (, , , and ) and slightly modifies the parameters of the broad line (; linewidth = 40.00(50) mT) but does not change Species 1, assigned to Cu(II) species immobilized into resin pores in cathecolate-type coordination sites. Species 2 is assigned to Cu(II) species immobilized at the outer resin surface. Upon extended heating, a reversible formation of semiquinone-type paramagnetic radicals () is observed, assigned to the partial collapse of the resin polymeric network. Marcelo H. Herbst and Ney V. Vugman Copyright © 2015 Marcelo H. Herbst and Ney V. Vugman. All rights reserved. Insight into the Interaction between the HIV-1 Integrase Inhibitor Elvitegravir and Bovine Serum Albumin: A Spectroscopic Study Tue, 24 Mar 2015 12:30:06 +0000 http://www.hindawi.com/journals/jspec/2015/435674/ The interaction between the anti-HIV drug Elvitegravir (EVG) and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy and UV-visible absorption spectra. The mechanism for quenching the fluorescence of BSA by EVG is discussed. It was found that EVG can quench the intrinsic fluorescence of BSA through a static quenching procedure. The quenching type, association constant, and number of binding sites were investigated. The binding constant of EVG with BSA was calculated at different temperatures based on fluorescence quenching results. The thermodynamic parameters , , and were determined. The positive and negative and values showed that a spontaneous interaction may involve both roles of hydrophobic interaction and hydrogen bonding. The interaction of BSA with EVG was also confirmed by UV absorption spectra. The average distance, , between donor (BSA) and acceptor (EVG) was obtained according to Förster’s theory of nonradiation energy transfer. Synchronous fluorescence and three-dimensional fluorescence spectra were used to investigate the conformational change of BSA molecules that occur upon addition of EVG and showed, upon binding, a possibility of increasing hydrophobicity around tryptophan residues of BSA. Ali Saber Abdelhameed Copyright © 2015 Ali Saber Abdelhameed. All rights reserved. Detection of Dissolved Carbon Monoxide in Transformer Oil Using 1.567 m Diode Laser-Based Photoacoustic Spectroscopy Tue, 24 Mar 2015 10:12:42 +0000 http://www.hindawi.com/journals/jspec/2015/737635/ Carbon monoxide (CO) is one of the most important fault characteristic gases dissolved in power transformer oil. With the advantages of high sensitivity and accuracy, long-term stability, and short detection time, photoacoustic spectroscopy (PAS) has been proven to be one promising sensing technology for trace gas recognition. In this investigation, a tunable PAS experimental system based on a distributed-feedback (DFB) diode laser was proposed for recognizing dissolved CO in transformer oil. The molecular spectral line of CO gas detection was selected at 1.567 μm in the whole experiment. Relationships between the photoacoustic (PA) signal and gas pressure, temperature, laser power, and CO gas concentration were measured and discussed in detail, respectively. Finally, based on the least square regression theory, a novel quantitative identification method for CO gas detection with the PAS experimental system was proposed. And a comparative research about the gas detection performances performed by the PAS system and gas chromatography (GC) measurement was presented. All results lay a solid foundation for exploring a portable and tunable CO gas PAS detection device for practical application in future. Qu Zhou, Chao Tang, Shiping Zhu, Weigen Chen, and Xiaojuan Peng Copyright © 2015 Qu Zhou et al. All rights reserved. Hydrothermal Synthesis and Structural Characterization of NiO/SnO2 Composites and Hydrogen Sensing Properties Tue, 24 Mar 2015 09:13:17 +0000 http://www.hindawi.com/journals/jspec/2015/450485/ Pure SnO2 and NiO doped SnO2 nanostructures were successfully synthesized via a simple and environment-friendly hydrothermal method. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectra (XPS) were used to investigate the crystalline structures, surface morphologies and microstructures, and element components and their valences of the as-synthesized samples. Furthermore, planar chemical gas sensors based on the synthesized pure SnO2 and NiO/SnO2 composites were fabricated and their sensing performances to hydrogen, an important fault characteristic gas dissolved in power transformer oil, were investigated in detail. Gas sensing experiments indicate that the NiO/SnO2 composites showed much higher gas response and lower working temperature than those of pure SnO2, which could be ascribed to the formation of p-n heterojunctions between p-type NiO and n-type SnO2. These results demonstrate that the as-synthesized NiO/SnO2 composites a promising hydrogen sensing material. Chao Wei, Bin Bo, Fengbo Tao, Yuncai Lu, Shudi Peng, Wei Song, and Qu Zhou Copyright © 2015 Chao Wei et al. All rights reserved. Evaluation of Salmon Adhesion on PET-Metal Interface by ATR, FT-IR, and Raman Spectroscopy Tue, 24 Mar 2015 06:55:45 +0000 http://www.hindawi.com/journals/jspec/2015/835798/ The material employed in this study is an ecoefficient, environmentally friendly, chromium (VI)-free (noncarcinogenic) metal polymer. The originality of the research lies in the study of the effect of new production procedures of salmon on metal packaging with multilayer polyethylene terephthalate (PET) polymer coatings. Our hypothesis states that the adhesion of postmortem salmon muscles to the PET polymer coating produces surface and structural changes that affect the functionality and limit the useful life of metal containers, compromising therefore their recycling capacity as ecomaterials. This work is focused on studying the effects of the biochemical changes of postmortem salmon on the PET coating and how muscle degradation favors adhesion to the container. The experimental design considered a series of laboratory tests of containers simulating the conditions of canned salmon, chemical and physical tests of food-contact canning to evaluate the adhesion, and characterization of changes in the multilayer PET polymer by electron microscopy, ATR, FT-IR, and Raman spectroscopy analyses. The analyses determined the effect of heat treatment of containers on the loss of freshness of canned fish and the increased adhesion to the container wall, and the limited capability of the urea treatment to remove salmon muscle from the container for recycling purposes. E. Zumelzu, M. J. Wehrhahn, F. Rull, H. Pesenti, O. Muñoz, and R. Ugarte Copyright © 2015 E. Zumelzu et al. All rights reserved. Orientation Mapping of Extruded Polymeric Composites by Polarized Micro-Raman Spectroscopy Tue, 24 Mar 2015 06:43:03 +0000 http://www.hindawi.com/journals/jspec/2015/518054/ Molecular orientation has a strong influence on polymeric composite materials’ mechanical properties. In this paper we describe the use of polarized micro-Raman spectroscopy as a powerful tool to map out the molecular orientation of a uniaxially oriented polypropylene- (PP-) based composite material. Initial samples exhibited a high degree of surface fibrillation upon cutting. Raman spectroscopy was used to characterize the degree of orientation in the skin and guide the development of the posttreatment process to optimize the skin relaxation while maintaining the high degree of orientation in the rest of the board. The PP oriented polymer composite (OPC) was oriented through an extrusion process and its surface was then treated to achieve relaxation. Micro-Raman analysis at the surface region demonstrated the surface orientation relaxation, and the results provide an effective way to correlate the extent of relaxation and process conditions. Larger scale orientation mapping was also carried out over the entire cross-section (12.7 cm × 2.54 cm). The results agree well with prior expectation of the molecular orientation based on the extrusion and subsequent quenching process. The methodologies described here can be readily applied to other polymeric systems. Xiaoyun Chen, M. Anne Leugers, Tim Kirch, and Jamie Stanley Copyright © 2015 Xiaoyun Chen et al. All rights reserved. NIRS Characterization of Paper Pulps to Predict Kappa Number Mon, 23 Mar 2015 13:15:10 +0000 http://www.hindawi.com/journals/jspec/2015/104609/ Rice is one of the most abundant food crops in the world and its straw stands as an important source of fibres both from an economic and an environmental point of view. Pulp characterization is of special relevance in works involving alternative raw materials, since pulp properties are closely linked to the quality of the final product. One of the analytical techniques that can be used in pulp characterization is near-infrared spectroscopy (NIRS). The use of NIRS has economic and technical advantages over conventional techniques. This paper aims to discuss the convenience of using NIRS to predict Kappa number in rice straw pulps produced under different conditions. We found that the resulting Kappa number can be acceptably estimated by NIRS, as the errors obtained with that method are similar to those found for other techniques. Ana Moral, Elena Cabeza, Roberto Aguado, and Antonio Tijero Copyright © 2015 Ana Moral et al. All rights reserved.