Application of Moessbauer spectroscopy for the characterization of iron-containing catalysts

International Nuclear Information System (INIS)

Phillips, J.

1998-01-01

Work in our laboratory demonstrates the unique analytical power as well as the limits of Moessbauer Spectroscopy (MES) as a tool for characterizing the size and phase of supported iron containing catalyst particles, particularly carbon supported catalysts. The major challenge in employing MES to characterize catalytic particles is understanding the impact of the relaxation effects on the spectra. Proper methods yield particle size and phase information, whereas improper interpretation can lead to the misidentification of phases. This is illustrated by feeding ersatz 'relaxed' spectra data, generated mathematically with a program which accounts for all aspects of relaxation, to a standard fitting routine. The fitting routine misinterprets the data and provides false phase identification. Methods for recognizing relaxation phenomena and strategies for extracting correct information from relaxed spectra are reviewed. Also reviewed are the major findings of studies on carbon supported catalysts. For example, MES studies, in conjunction with other techniques, demonstrate that bulk and surface structures which are easily accessible for carbon supported bimetallics are generally not found on refractory oxides

The Exoplanet Characterization ToolKit (ExoCTK)

Science.gov (United States)

Stevenson, Kevin; Fowler, Julia; Lewis, Nikole K.; Fraine, Jonathan; Pueyo, Laurent; Valenti, Jeff; Bruno, Giovanni; Filippazzo, Joseph; Hill, Matthew; Batalha, Natasha E.; Bushra, Rafia

2018-01-01

The success of exoplanet characterization depends critically on a patchwork of analysis tools and spectroscopic libraries that currently require extensive development and lack a centralized support system. Due to the complexity of spectroscopic analyses and initial time commitment required to become productive, there are currently a limited number of teams that are actively advancing the field. New teams with significant expertise, but without the proper tools, face prohibitively steep hills to climb before they can contribute. As a solution, we are developing an open-source, modular data analysis package in Python and a publicly facing web interface focused primarily on atmospheric characterization of exoplanets and exoplanet transit observation planning with JWST. The foundation of these software tools and libraries exist within pockets of the exoplanet community. Our project will gather these seedling tools and grow a robust, uniform, and well maintained exoplanet characterization toolkit.

In vivo characterization of colorectal metastases in human liver using diffuse reflectance spectroscopy: toward guidance in oncological procedures

Science.gov (United States)

Spliethoff, Jarich W.; de Boer, Lisanne L.; Meier, Mark A. J.; Prevoo, Warner; de Jong, Jeroen; Kuhlmann, Koert; Bydlon, Torre M.; Sterenborg, Henricus J. C. M.; Hendriks, Benno H. W.; Ruers, Theo J. M.

2016-09-01

There is a strong need to develop clinical instruments that can perform rapid tissue assessment at the tip of smart clinical instruments for a variety of oncological applications. This study presents the first in vivo real-time tissue characterization during 24 liver biopsy procedures using diffuse reflectance (DR) spectroscopy at the tip of a core biopsy needle with integrated optical fibers. DR measurements were performed along each needle path, followed by biopsy of the target lesion using the same needle. Interventional imaging was coregistered with the DR spectra. Pathology results were compared with the DR spectroscopy data at the final measurement position. Bile was the primary discriminator between normal liver tissue and tumor tissue. Relative differences in bile content matched with the tissue diagnosis based on histopathological analysis in all 24 clinical cases. Continuous DR measurements during needle insertion in three patients showed that the method can also be applied for biopsy guidance or tumor recognition during surgery. This study provides an important validation step for DR spectroscopy-based tissue characterization in the liver. Given the feasibility of the outlined approach, it is also conceivable to make integrated fiber-optic tools for other clinical procedures that rely on accurate instrument positioning.

Online and Certifiable Spectroscopy Courses Using Information and Communication Tools. a Model for Classrooms and Beyond

Science.gov (United States)

Krishnan, Mangala Sunder

2015-06-01

Online education tools and flipped (reverse) class models for teaching and learning and pedagogic and andragogic approaches to self-learning have become quite mature in the last few years because of the revolution in video, interactive software and social learning tools. Open Educational resources of dependable quality and variety are also becoming available throughout the world making the current era truly a renaissance period for higher education using Internet. In my presentation, I shall highlight structured course content preparation online in several areas of spectroscopy and also the design and development of virtual lab tools and kits for studying optical spectroscopy. Both elementary and advanced courses on molecular spectroscopy are currently under development jointly with researchers in other institutions in India. I would like to explore participation from teachers throughout the world in the teaching-learning process using flipped class methods for topics such as experimental and theoretical microwave spectroscopy of semi-rigid and non-rigid molecules, molecular complexes and aggregates. In addition, courses in Raman, Infrared spectroscopy experimentation and advanced electronic spectroscopy courses are also envisaged for free, online access. The National Programme on Technology Enhanced Learning (NPTEL) and the National Mission on Education through Information and Communication Technology (NMEICT) are two large Government of India funded initiatives for producing certified and self-learning courses with financial support for moderated discussion forums. The learning tools and interactive presentations so developed can be used in classrooms throughout the world using flipped mode of teaching. They are very much sought after by learners and researchers who are in other areas of learning but want to contribute to research and development through inter-disciplinary learning. NPTEL is currently is experimenting with Massive Open Online Course (MOOC

Characterization of Kevlar Using Raman Spectroscopy

Science.gov (United States)

Washer, Glenn; Brooks, Thomas; Saulsberry, Regor

2007-01-01

This paper explores the characterization of Kevlar composite materials using Raman spectroscopy. The goal of the research is to develop and understand the Raman spectrum of Kevlar materials to provide a foundation for the development of nondestructive evaluation (NDE) technologies based on the interaction of laser light with the polymer Kevlar. The paper discusses the fundamental aspects of experimental characterization of the spectrum of Kevlar, including the effects of incident wavelength, polarization and laser power. The effects of environmental exposure of Kevlar materials on certain characteristics of its Raman spectrum are explored, as well as the effects of applied stress. This data may provide a foundation for the development of NDE technologies intended to detect the in-situ deterioration of Kevlar materials used for engineering applications that can later be extended to other materials such as carbon fiber composites.

Characterizing the hydration state of L-threonine in solution using terahertz time-domain attenuated total reflection spectroscopy

Science.gov (United States)

Huang, Huachuan; Liu, Qiao; Zhu, Liguo; Li, Zeren

2018-01-01

The hydration of biomolecules is closely related to the dynamic process of their functional expression, therefore, characterizing hydration phenomena is a subject of keen interest. However, direct measurements on the global hydration state of biomolecules couldn't have been acquired using traditional techniques such as thermodynamics, ultrasound, microwave spectroscopy or viscosity, etc. In order to realize global hydration characterization of amino acid such as L-threonine, terahertz time-domain attenuated total reflectance spectroscopy (THz-TDS-ATR) was adopted in this paper. By measuring the complex permittivity of L-threonine solutions with various concentrations in the THz region, the hydration state and its concentration dependence were obtained, indicating that the number of hydrous water decreased with the increase of concentration. The hydration number was evaluated to be 17.8 when the molar concentration of L-threonine was 0.34 mol/L, and dropped to 13.2 when the molar concentration increased to 0.84 mol/L, when global hydration was taken into account. According to the proposed direct measurements, it is believed that the THz-TDS-ATR technique is a powerful tool for studying the picosecond molecular dynamics of amino acid solutions.

In-situ Raman spectroscopy as a characterization tool for carbon electrodes

Energy Technology Data Exchange (ETDEWEB)

Panitz, J -C; Joho, F B; Novak, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Lithium intercalation and de-intercalation into/from graphite electrodes in a nonaqueous electrolyte has been studied using in-situ Raman spectroscopy. Our experiments give information on the electrode-electrolyte interface with improved spatial resolution. The spectra taken from the electrode surface change with electrode potential. In this way, information on the nature of the chemical species present during charging and discharging half cycles is gained. For the first time, mapping techniques were applied to investigate if lithium intercalation proceeds homogeneously on the carbon electrode. (author) 3 figs., 1 tab., 4 refs.

Applications of the Raman spectroscopy in the materials characterization

International Nuclear Information System (INIS)

Jimenez S, S.; Escobar A, L.; Camacho L, M. A.

2011-01-01

The study field of the science and technology of surfaces and materials have been of primordial importance in the last years due to the impact that they have the knowledge that it generates in diverse areas. For this reason, the Mexican Society of Science and Technology of Surfaces and Materials has focused a good part of their investigation activities toward the materials science and technology development. Inside the investigation fields carried out by members of this Society, are the following: semiconductors, thin films, hard coatings, deposit techniques, plasmas, biomaterials, Ab-initio calculations, characterization techniques, photo-thermal properties, solar cells, nano science, magnetism, superconductivity and related topics. Among the techniques used for this purpose is the Raman Spectroscopy (Rs), which has demonstrated to be a powerful and versatile tool in the materials study. In the last three congresses that the Society has organized, an average of 42 works related with this topic have been presented, what gave the rule to prepare this book whose objective is on one hand diffusing part of the works that carry out different groups integrated with members of the Society that use the Rs like an important tool in its investigation work. A second objective is that it can serve like support to the students that begin to be involved, or that they are already involved, in topics where the Rs can have a decisive paper in the development of its projects. It is also expected that some of the topics included in the book are of utility for professors and researches that already uses the Rs, or that it can be of help for those who are beginning in this technique as alternative or like complementary analysis tool. (Author)

Characterizing aging effects of lithium ion batteries by impedance spectroscopy

International Nuclear Information System (INIS)

Troeltzsch, Uwe; Kanoun, Olfa; Traenkler, Hans-Rolf

2006-01-01

Impedance spectroscopy is one of the most promising methods for characterizing aging effects of portable secondary batteries online because it provides information about different aging mechanisms. However, application of impedance spectroscopy 'in the field' has some higher requirements than for laboratory experiments. It requires a fast impedance measurement process, an accurate model applicable with several batteries and a robust method for model parameter estimation. In this paper, we present a method measuring impedance at different frequencies simultaneously. We propose to use a composite electrode model, capable to describe porous composite electrode materials. A hybrid method for parameter estimation based on a combination of evolution strategy and Levenberg-Marquardt method allowed a robust and fast parameter calculation. Based on this approach, an experimental investigation of aging effects of a lithium ion battery was carried out. After 230 discharge/charge cycles, the battery showed a 14% decreased capacity. Modeling results show that series resistance, charge transfer resistance and Warburg coefficient changed thereby their values by approximately 60%. A single frequency impedance measurement, usually carried out at 1 kHz, delivers only information about series resistance. Impedance spectroscopy allows additionally the estimation of charge transfer resistance and Warburg coefficient. This fact and the high sensitivity of model parameters to capacity change prove that impedance spectroscopy together with an accurate modeling deliver information that significantly improve characterization of aging effects

Characterizing aging effects of lithium ion batteries by impedance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Troeltzsch, Uwe [University of the Bundeswehr Munich Institute for Measurement and Automation, 85579 Neubiberg (Germany)]. E-mail: uwe.troeltzsch@unibw-muenchen.de; Kanoun, Olfa [University of the Bundeswehr Munich Institute for Measurement and Automation, 85579 Neubiberg (Germany); Traenkler, Hans-Rolf [University of the Bundeswehr Munich Institute for Measurement and Automation, 85579 Neubiberg (Germany)

2006-01-20

Impedance spectroscopy is one of the most promising methods for characterizing aging effects of portable secondary batteries online because it provides information about different aging mechanisms. However, application of impedance spectroscopy 'in the field' has some higher requirements than for laboratory experiments. It requires a fast impedance measurement process, an accurate model applicable with several batteries and a robust method for model parameter estimation. In this paper, we present a method measuring impedance at different frequencies simultaneously. We propose to use a composite electrode model, capable to describe porous composite electrode materials. A hybrid method for parameter estimation based on a combination of evolution strategy and Levenberg-Marquardt method allowed a robust and fast parameter calculation. Based on this approach, an experimental investigation of aging effects of a lithium ion battery was carried out. After 230 discharge/charge cycles, the battery showed a 14% decreased capacity. Modeling results show that series resistance, charge transfer resistance and Warburg coefficient changed thereby their values by approximately 60%. A single frequency impedance measurement, usually carried out at 1 kHz, delivers only information about series resistance. Impedance spectroscopy allows additionally the estimation of charge transfer resistance and Warburg coefficient. This fact and the high sensitivity of model parameters to capacity change prove that impedance spectroscopy together with an accurate modeling deliver information that significantly improve characterization of aging effects.

Characterization of Egyptian coal from Sinai using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Eissa, N.A.; Abdel Meguid, M.M.; Deriu, A.; Albanese, G.

1983-08-01

The presence of iron bearing minerals in coal makes the Moessbauer Spectroscopy (MS) extremely useful for characterization of coals from different localities. In this paper the MS has been applied to characterize Egyptian coal from Sinai (Maghara). The chemical analysis of this coal is given. The MS results showed that pyritic sulphur (pyrite and marcasite) is the only bearing mineral in Egyptian coal. A review is given for the iron bearing minerals in coals from different countries measured by MS. (author)

Electrochemical impedance spectroscopy: An effective tool for a fast microbiological diagnosis

International Nuclear Information System (INIS)

Ramirez, Nardo; Regueiro, Angel; Arias, Olimpia; Contreras, Rolando

2009-01-01

Dielectric spectroscopy, also called electrochemical impedance spectroscopy, is traditionally used in monitoring corrosion and electro-deposition processes in the coating and characterization assessment of many kinds of sensors and semi-conductors. Its application in biotechnology for the characterization of cell cultures has, however, been notably expanded in the last decade. As a transductional principle, impedance has been applied in the field of microbiology as a means of detecting and quantifying pathogenic bacteria. This paper reviews the state-of-the-art of Impedance Microbiology, its progress and its applications for the detection of foodborne pathogenic bacteria, including the use of interdigitated microelectrodes, the development of chip-based impedance microbiology and the integration of impedance biosensors along with other techniques such as dielectrophoresis and electropermeabilization. Reference is made to basic components, definitions and principles of this technique, as well as to the explanation of the components and principles for cell culture design and the use of equivalent circuits for the analysis of the systems based on this alternative. (Author)

Use of photoacoustic mid-infrared spectroscopy to characterize soil properties and soil organic matter stability

Science.gov (United States)

Peltre, Clement; Bruun, Sander; Du, Changwen; Stoumann Jensen, Lars

2014-05-01

laboratory incubation and more classical soil parameters such as carbon and clay content for a range of 36 soils collected from various field experiments in Denmark. Partial least square (PLS) regression was used to correlate the collected FTIR-PAS spectra with the proportion of soil organic carbon mineralized after 34 weeks of incubation at 15° C and pF 2, taken as an indicator of the labile fraction of SOM. Results showed that it is possible to predict the labile fraction of SOM with FTIR PAS with similar accuracy as with NIRS (assessed in a previous study on the same soil set). FTIR-PAS offered the advantage over NIRS to allow identification of the chemical compounds positively or negatively correlated with the labile fraction of SOM. The band at 1612 cm-1 corresponding to polysaccharides, pectin and aromatic C=C was the band most positively correlated with labile SOM, which we attributed to the relative lability of fresh plant debris rich in polysaccharide and aromatic lignin. The band at 1560-1590 cm-1 assigned to N=H, C=N and aromatic C=C vibration was the band most negatively correlated with the labile fraction of SOM, confirming the abundance of nitrogenous and aromatic compounds in stabilized SOM. In conclusion, FTIR-PAS has proved to be a powerful tool to characterize the labile fraction of SOM, offering several benefits over reflectance spectroscopy techniques.

Raman spectroscopy as a tool for the characterization and classification of pollen; Raman-Spektroskopie als Werkzeug fuer die Charakterisierung und Klassifizierung von Pollen

Energy Technology Data Exchange (ETDEWEB)

Schulte, Franziska

2010-09-20

The chemical composition of pollen, the physiological containers that produce the male gametophytes of seed plants, has been a subject of research of plant physiologists, biochemists, and lately even material scientists for various reasons. The aim of this work was the analysis of whole pollen grains and pollen components by Raman Spectroscopy. These experiments were complemented by other techniques such as Enviromental Scanning Electron Microscopy (ESEM), High-Performance- Thin-Layer-Chromatography (HPTLC), Infrared Spectroscopy (IR) and Nuclear-Magnetic-Resonance Spectroscopy (NMR). As reported here, individual fresh pollen grains and their morphological constituents can be characterized and also classified in situ without prior preparation. Classification of pollen is based on their biochemical fingerprint revealed in their Raman spectrum. Raman spectroscopy is nondestructive and can be carried out with single pollen grains or fragments. It could be shown that the biochemical makeup of the pollen (as a part of the recognition/mating system) is altered during formation of a new biological species and that the species-specific chemical similarities and dissimilarities indeed reflect in the Raman spectral fingerprint. On the basis of the chemical information, unsupervised multivariate analysis consisting of hierarchical clustering revealed in most cases chemical similarities between species that were indicative of both phylogenetic relationship and matin behavior. Therefore experiments were conducted that gave the in situ Raman spectroscopic signatures ot the carotenoid molecules. As the data indicates, the in situ Raman spectra of the carotenoid molecules measured in single intact pollen grains provide in situ evidence of interspecies variations in pollen carotenoid content, structure, and/or assembly without prior purification. Results from HPTLC confirmed that carotenoid composition varied greatly between species and that the different in situ spectral

UV-VIS and photoluminescence spectroscopy for nanomaterials characterization

CERN Document Server

2013-01-01

Second volume of a 40-volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about UV-visible and photoluminescence spectroscopy for the characterization of nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume essential reading for research scientists in academia and industry in the related fields.

The characterization of natural gemstones using non-invasive FT-IR spectroscopy: New data on tourmalines.

Science.gov (United States)

Mercurio, Mariano; Rossi, Manuela; Izzo, Francesco; Cappelletti, Piergiulio; Germinario, Chiara; Grifa, Celestino; Petrelli, Maurizio; Vergara, Alessandro; Langella, Alessio

2018-02-01

Fourteen samples of tourmaline from the Real Museo Mineralogico of Federico II University (Naples) have been characterized through multi-methodological investigations (EMPA-WDS, SEM-EDS, LA-ICP-MS, and FT-IR spectroscopy). The samples show different size, morphology and color, and are often associated with other minerals. Data on major and minor elements allowed to identify and classify tourmalines as follows: elbaites, tsilaisite, schorl, dravites, uvites and rossmanite. Non-invasive, non-destructive FT-IR and in-situ analyses were carried out on the same samples to validate this chemically-based identification and classification. The results of this research show that a complete characterization of this mineral species, usually time-consuming and expensive, can be successfully achieved through non-destructive FT-IR technique, thus representing a reliable tool for a fast classification extremely useful to plan further analytical strategies, as well as to support gemological appraisals. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluorescence spectroscopy: a tool to characterize humic substances in soil colonized by microorganisms?

Czech Academy of Sciences Publication Activity Database

Řezáčová, Veronika; Gryndler, Milan

2006-01-01

Roč. 51, č. 3 (2006), s. 215-221 ISSN 0015-5632 R&D Projects: GA ČR GA526/03/0188 Institutional research plan: CEZ:AV0Z50200510 Keywords : fluorescence spectroscopy * humic substances * microorganism Subject RIV: EE - Microbiology, Virology Impact factor: 0.963, year: 2006

Site-Specific Characterization of Cytochrome P450cam Conformations by Infrared Spectroscopy.

Science.gov (United States)

Basom, Edward J; Maj, Michał; Cho, Minhaeng; Thielges, Megan C

2016-06-21

Conformational changes are central to protein function but challenging to characterize with both high spatial and temporal precision. The inherently fast time scale and small chromophores of infrared (IR) spectroscopy are well-suited for characterization of potentially rapidly fluctuating environments, and when frequency-resolved probes are incorporated to overcome spectral congestion, enable characterization of specific sites in proteins. We selectively incorporated p-cyanophenylalanine (CNF) as a vibrational probe at five distinct locations in the enzyme cytochrome P450cam and used IR spectroscopy to characterize the environments in substrate and/or ligand complexes reflecting those in the catalytic cycle. Molecular dynamics (MD) simulations were performed to provide a structural basis for spectral interpretation. Together the experimental and simulation data suggest that the CN frequencies are sensitive to both long-range influences, resulting from the particular location of a residue within the enzyme, as well as short-range influences from hydrogen bonding and packing interactions. The IR spectra demonstrate that the environments and effects of substrate and/or ligand binding are different at each position probed and also provide evidence that a single site can experience multiple environments. This study illustrates how IR spectroscopy, when combined with the spectral decongestion and spatial selectivity afforded by CNF incorporation, provides detailed information about protein structural changes that underlie function.

Characterization Of Cobalt-Exchanged Zeolite A By DRIFT Spectroscopy

Science.gov (United States)

Kappers, M. J.; van der Maas, John H.; Chalmers, J. M.; Howard, J.

1989-12-01

In-situ DRIFT spectroscopy has been succesfully used for the characterization of Co4Na4-A. Dehydration of the zeolite A appears to involve formation and breakdown of hydration complexes and hydrolysis. The position of cations and hydroxyl groups within the zeolite structure was derived from the adsorption of carbon monoxide and acetonitrile.

Spectroscopy as a diagnostic tool for urban soil contaminants

Science.gov (United States)

Brook, Anna; Kopel, Daniella

2014-05-01

Urbanization has become one of the major forces of change around the globe. Land use transformation, especially urbanization has the most profound influences of human activities because it affects so many of the planet's physical and biological systems. Land use changes directly impact the ability of the earth to continue to provide ecological services to human society and the other occupants of the ecosystems. The urban process gradually degrades and transforms agricultural and natural ecosystems into built environments. The urban environment includes cities, suburbs, peri-urban areas and towns. Urban ecosystems are highly heterogeneous due to the variety of land covers and land purposes. Thus, the choices on managing the extent and arranging the land cover patches (e.g., lawns) assist to shape the emergent structure and function of the urban ecosystems. As a result of ecological conditions and current management status the urban soils show substantial spatial heterogeneity. Whereas, adverse effects of pollutants on ecosystems have been demonstrated, one important need for environmental impact assessment have been defined as maintenance of long-term monitoring systems, which can enable to improve monitoring, modelling and assessment of various stressors in agriculture environment. Diffuse reflectance spectroscopy and diffuse reflectance Fourier-transform infrared (FTIR) spectroscopy across visible-near- short- mid- and long- wave infrared (0.4-14μm) has the potential to meet this demand. Relationships between spectral reflectance and soil properties, such as grain size distribution, moisture, iron oxides, carbonate content, and organic matter, have already been established in many studies (Krishnan et al. 1980, Ben-Dor and Banin 1995, Jarmer et al. 2008, Richter et al. 2009). The aims of this study are to develop diagnostic tool for heavy metals, polycyclic aromatic hydrocarbons, asbestos and other anthropogenic contaminants in urban soil using spectroscopy

Vibrational spectroscopy

Science.gov (United States)

Umesh P. Agarwal; Rajai Atalla

2010-01-01

Vibrational spectroscopy is an important tool in modern chemistry. In the past two decades, thanks to significant improvements in instrumentation and the development of new interpretive tools, it has become increasingly important for studies of lignin. This chapter presents the three important instrumental methods-Raman spectroscopy, infrared (IR) spectroscopy, and...

Iron oxides characterization by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Basurto Sanchez, R.

1993-01-01

In this work rust development on low carbon wire surface after the conformation process at different temperatures was studied by Moessbauer spectroscopy. The characterization was made by determining the following spectral parameters; 1) Quadrupole splitting, 2) Isomer shift, and 3) Magnetic splitting. The area quantification determined the percentage amount of three different iron oxides. These iron oxides were: a) Wustite (Fe O), b) Hematite (Fe 2 O 3 ), and c) Magnetite (Fe 3 O 4 ) which were present in the rust studied. With the results it was possible to establish the best temperature to favor the development of each of these iron oxides. (Author)

Redox Chemisty of Tantalum Clusters on Silica Characterized by X-ray Absorption Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Nemana,S.; Gates, B.

2006-01-01

SiO{sub 2}-supported clusters of tantalum were synthesized from adsorbed Ta(CH{sub 2}Ph){sub 5} by treatment in H{sub 2} at 523 K. The surface species were characterized by X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray absorption near edge spectroscopy (XANES)) and ultraviolet-visible spectroscopy. The EXAFS data show that SiOO{sub 2}-supported tantalum clusters were characterized by a Ta-Ta coordination number of approximately 2, consistent with the presence of tritantalum clusters, on average. When these were reduced in H{sub 2} and reoxidized in O{sub 2}, the cluster nuclearity remained essentially unchanged, although reduction and oxidation occurred, respectively, as shown by XANES and UV-vis spectra; in the reoxidation, the tantalum oxidation state change was approximately two electronic charges per tritantalum cluster. The data demonstrate an analogy between the chemistry of group 5 metals on the SiO{sub 2} support and their chemistry in solution, as determined by the group of Cotton.

Characterizing aeroallergens by infrared spectroscopy of fungal spores and pollen.

Directory of Open Access Journals (Sweden)

Boris Zimmermann

Full Text Available Fungal spores and plant pollen cause respiratory diseases in susceptible individuals, such as asthma, allergic rhinitis and hypersensitivity pneumonitis. Aeroallergen monitoring networks are an important part of treatment strategies, but unfortunately traditional analysis is time consuming and expensive. We have explored the use of infrared spectroscopy of pollen and spores for an inexpensive and rapid characterization of aeroallergens.The study is based on measurement of spore and pollen samples by single reflectance attenuated total reflectance Fourier transform infrared spectroscopy (SR-ATR FTIR. The experimental set includes 71 spore (Basidiomycota and 121 pollen (Pinales, Fagales and Poales samples. Along with fresh basidiospores, the study has been conducted on the archived samples collected within the last 50 years.The spectroscopic-based methodology enables clear spectral differentiation between pollen and spores, as well as the separation of confamiliar and congeneric species. In addition, the analysis of the scattering signals inherent in the infrared spectra indicates that the FTIR methodology offers indirect estimation of morphology of pollen and spores. The analysis of fresh and archived spores shows that chemical composition of spores is well preserved even after decades of storage, including the characteristic taxonomy-related signals. Therefore, biochemical analysis of fungal spores by FTIR could provide economical, reliable and timely methodologies for improving fungal taxonomy, as well as for fungal identification and monitoring. This proof of principle study shows the potential for using FTIR as a rapid tool in aeroallergen studies. In addition, the presented method is ready to be immediately implemented in biological and ecological studies for direct measurement of pollen and spores from flowers and sporocarps.

High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter

International Nuclear Information System (INIS)

Monkenbusch, M.; Richter, D.

2007-01-01

Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

Frequency-comb-assisted broadband precision spectroscopy with cascaded diode lasers

DEFF Research Database (Denmark)

Liu, Junqiu; Brasch, Victor; Pfeiffer, Martin H. P.

2016-01-01

Frequency-comb-assisted diode laser spectroscopy, employing both the accuracy of an optical frequency comb and the broad wavelength tuning range of a tunable diode laser, has been widely used in many applications. In this Letter, we present a novel method using cascaded frequency agile diode lasers......, which allows us to extend the measurement bandwidth to 37.4 THz (1355-1630 nm) at megahertz resolution with scanning speeds above 1 THz/s. It is demonstrated as a useful tool to characterize a broadband spectrum for molecular spectroscopy, and in particular it enables us to characterize the dispersion...

Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Hellman, Hal

1968-01-01

This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

Photoacoustic spectroscopy applied to the optical characterization of calcium phosphates for biomedical use

Energy Technology Data Exchange (ETDEWEB)

Mendez G, M. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Cruz O, A. [CINVESTAV, Dept. of Physics, 07360 Mexico D.F. (Mexico)

2007-07-01

Full text: Photoacoustic Spectroscopy (PAS), based on the Rosencwaig and Gersho model, has been used for thermal and optical characterization of diverse materials. The use of PAS has become an important tool because is a nondestructive and no contact analytical technique. Furthermore its use to measure optical absorption spectra has advantages over the usual transmission measurements due to important features as the fact that scattered light does not disturb the measurements significantly and also the sample don't need to be prepared to have good quality surfaces. Then the optical properties of biological samples can be easily investigated with this technique. In the present study PAS is applied to obtain the optical absorption spectra of hydroxyapatite (HAp) [Ca{sub 10} (PO{sub 4} ){sub 6} (OH ){sub 2}] and bioactive calcium phosphates. The spectra of these samples ranged from 300 to 800 nm. All samples were prepared in a power form with particle size < 741m. Complementary studies X-ray diffraction and EDC were performed. (Author)

Characterization of redeposited carbon layers on TEXTOR limiter by Laser Raman spectroscopy

International Nuclear Information System (INIS)

Egashira, K.; Tanabe, T.; Yoshida, M.; Nakazato, H.; Philipps, V.; Brezinsek, S.; Kreter, A.

2011-01-01

Highlights: ► Laser Raman technique has applied to analyze the deposited carbon layers on TEXTOR test limiters of C and W. ► The carbon deposited layers showed the Raman spectra composed of G-peak and D-peak. ► For W limiter, hydrogen concentrations in the deposited carbon layers and their thicknesses correlated to the two peaks. ► The Laser Raman spectroscopy is a promising tool for in situ analysis of carbon redeposit layers on plasma facing W materials. - Abstract: Laser Raman spectroscopy is quite sensitive to detect the changes of graphite structure. In this study, the Laser Raman technique was applied to analyze the deposited carbon layers on TEXTOR test limiters of carbon (C) and tungsten (W) produced by intentional carbon deposition experiments by methane gas puffing. The carbon deposited layers showed the Raman spectra composed of two broad peaks, G-peak and D-peak, centered at around 1580 and 1355 cm −1 respectively. For W limiter, the G-peak position and the integrated intensity of the two peaks well correlate to hydrogen concentrations in the deposited carbon layers and their thicknesses, respectively. Hence Laser Raman spectroscopy is a promising tool for the in situ analysis of carbon redeposit layers on plasma facing W materials and probably on Be materials.

The hallmarks of breast cancer by Raman spectroscopy

Science.gov (United States)

Abramczyk, H.; Surmacki, J.; Brożek-Płuska, B.; Morawiec, Z.; Tazbir, M.

2009-04-01

This paper presents new biological results on ex vivo breast tissue based on Raman spectroscopy and demonstrates its power as diagnostic tool with the key advantage in breast cancer research. The results presented here demonstrate the ability of Raman spectroscopy to accurately characterize cancer tissue and distinguish between normal, malignant and benign types. The goal of the paper is to develop the diagnostic ability of Raman spectroscopy in order to find an optical marker of cancer in the breast tissue. Applications of Raman spectroscopy in breast cancer research are in the early stages of development in the world. To the best of our knowledge, this paper is one of the most statistically reliable reports (1100 spectra, 99 patients) on Raman spectroscopy-based diagnosis of breast cancers among the world women population.

The use of UV-visible reflectance spectroscopy as an objective tool to evaluate pearl quality.

Science.gov (United States)

Agatonovic-Kustrin, Snezana; Morton, David W

2012-07-01

Assessing the quality of pearls involves the use of various tools and methods, which are mainly visual and often quite subjective. Pearls are normally classified by origin and are then graded by luster, nacre thickness, surface quality, size, color and shape. The aim of this study was to investigate the capacity of Artificial Neural Networks (ANNs) to classify and estimate the quality of 27 different pearls from their UV-Visible spectra. Due to the opaque nature of pearls, spectroscopy measurements were performed using the Diffuse Reflectance UV-Visible spectroscopy technique. The spectra were acquired at two different locations on each pearl sample in order to assess surface homogeneity. The spectral data (inputs) were smoothed to reduce the noise, fed into ANNs and correlated to the pearl's quality/grading criteria (outputs). The developed ANNs were successful in predicting pearl type, mollusk growing species, possible luster and color enhancing, donor condition/type, recipient/host color, donor color, pearl luster, pearl color, origin. The results of this study shows that the developed UV-Vis spectroscopy-ANN method could be used as a more objective method of assessing pearl quality (grading) and may become a valuable tool for the pearl grading industry.

From Femtosecond Dynamics to Breast Cancer Diagnosis by Raman Spectroscopy

International Nuclear Information System (INIS)

Abramczyk, H.; Placek, I.; Brozek-Pluska, B.; Kurczewski, K.; Morawiec, Z.; Tazbir, M.

2007-01-01

This paper presents new results based on Raman spectroscopy and demonstrates its utilisation as a diagnostic and development tool with the key advantage in breast cancer research. Applications of Raman spectroscopy in cancer research are in the early stages of development. However, research presented here as well as performed in a few other laboratories demonstrate the ability of Raman spectroscopy to accurately characterize cancer tissue and distinguish between normal, malignant and benign types. The main goals of bio-Raman spectroscopy at this stage are threefold. Firstly, the aim is to develop the diagnostic ability of Raman spectroscopy so it can be implemented in a clinical environment, producing accurate and rapid diagnoses. Secondly, the aim is to optimize the technique as a diagnostic tool for the non-invasive real time medical applications. Thirdly, the aim is to formulate some hypothesis based on Raman spectroscopy on the molecular mechanism which drives the transformation of normal human cells into highly malignant derivatives. To the best of our knowledge, this is the most statistically reliable report on Raman spectroscopy-based diagnosis of breast cancers among the world women population

Evaluating minerals of environmental concern using spectroscopy

Science.gov (United States)

Swayze, G.A.; Clark, R.N.; Higgins, C.T.; Kokaly, R.F.; Livo, K. Eric; Hoefen, T.M.; Ong, C.; Kruse, F.A.

2006-01-01

Imaging spectroscopy has been successfully used to aid researchers in characterizing potential environmental impacts posed by acid-rock drainage, ore-processing dust on mangroves, and asbestos in serpentine mineral deposits and urban dust. Many of these applications synergistically combine field spectroscopy with remote sensing data, thus allowing more-precise data calibration, spectral analysis of the data, and verification of mapping. The increased accuracy makes these environmental evaluation tools efficient because they can be used to focus field work on those areas most critical to the research effort. The use of spectroscopy to evaluate minerals of environmental concern pushes current imaging spectrometer technology to its limits; we present laboratory results that indicate the direction for future designs of imaging spectrometers.

Surface science tools for nanomaterials characterization

CERN Document Server

2015-01-01

Fourth volume of a 40volume series on nano science and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about Surface Science Tools for Nanomaterials Characterization. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.

Lifetime spectroscopy a method of defect characterization in silicon for photovoltaic applications

CERN Document Server

Rein, Stefan

2005-01-01

Lifetime spectroscopy is one of the most sensitive diagnostic tools for the identification and analysis of impurities in semiconductors. Since it is based on the recombination process, it provides insight into precisely those defects that are relevant to semiconductor devices such as solar cells. This book introduces a transparent modeling procedure that allows a detailed theoretical evaluation of the spectroscopic potential of the different lifetime spectroscopic techniques. The various theoretical predictions are verified experimentally with the context of a comprehensive study on different metal impurities. The quality and consistency of the spectroscopic results, as explained here, confirms the excellent performance of lifetime spectroscopy.

Characterization of Modified and Polymer Coated Alumina Surfaces by Infrared Spectroscopy

Directory of Open Access Journals (Sweden)

Ashraf Yehia El-Naggar

2013-01-01

Full Text Available The prepared, modified, and coated alumina surfaces were characterized by infrared spectroscopy (FTIR to investigate the surface properties of the individual and double modified samples. FTIR helps in reporting the changes occurred in hydroxyl groups as well as the structure changes as a result of thermal treating, hydrothermal treating, silylation treating, alkali metal treating, coating, and bonding with polymer. FTIR spectroscopy represents the strength and abundance of surface acidic OH which determine the adsorption properties of polar and nonpolar sorbents. Generally, all treated samples exhibit decrease of OH groups compared with those of parent ones producing alumina surfaces of different adsorptive powers.

Borehole Tool for the Comprehensive Characterization of Hydrate-bearing Sediments

KAUST Repository

Dai, Sheng; Santamarina, Carlos

2018-01-01

Reservoir characterization and simulation require reliable parameters to anticipate hydrate deposits responses and production rates. The acquisition of the required fundamental properties currently relies on wireline logging, pressure core testing, and/or laboratory ob-servations of synthesized specimens, which are challenged by testing capabilities and in-nate sampling disturbances. The project reviews hydrate-bearing sediments, properties, and inherent sampling effects, albeit lessen with the developments in pressure core technology, in order to develop robust correlations with index parameters. The resulting information is incorporated into a tool for optimal field characterization and parameter selection with un-certainty analyses. Ultimately, the project develops a borehole tool for the comprehensive characterization of hydrate-bearing sediments at in situ, with the design recognizing past developments and characterization experience and benefited from the inspiration of nature and sensor miniaturization.

Borehole Tool for the Comprehensive Characterization of Hydrate-bearing Sediments

KAUST Repository

Dai, Sheng

2018-02-01

Reservoir characterization and simulation require reliable parameters to anticipate hydrate deposits responses and production rates. The acquisition of the required fundamental properties currently relies on wireline logging, pressure core testing, and/or laboratory ob-servations of synthesized specimens, which are challenged by testing capabilities and in-nate sampling disturbances. The project reviews hydrate-bearing sediments, properties, and inherent sampling effects, albeit lessen with the developments in pressure core technology, in order to develop robust correlations with index parameters. The resulting information is incorporated into a tool for optimal field characterization and parameter selection with un-certainty analyses. Ultimately, the project develops a borehole tool for the comprehensive characterization of hydrate-bearing sediments at in situ, with the design recognizing past developments and characterization experience and benefited from the inspiration of nature and sensor miniaturization.

Borehole Tool for the Comprehensive Characterization of Hydrate-bearing Sediments

Energy Technology Data Exchange (ETDEWEB)

Dai, Sheng [Georgia Inst. of Technology, Atlanta, GA (United States); Santamarina, J. Carlos [Georgia Inst. of Technology, Atlanta, GA (United States); King Abdullah Univ. of Science and Technology (KAUST), Thuwal (Saudi Arabia)

2017-12-30

Reservoir characterization and simulation require reliable parameters to anticipate hydrate deposits responses and production rates. The acquisition of the required fundamental properties currently relies on wireline logging, pressure core testing, and/or laboratory observations of synthesized specimens, which are challenged by testing capabilities and innate sampling disturbances. The project reviews hydrate-bearing sediments, properties, and inherent sampling effects, albeit lessen with the developments in pressure core technology, in order to develop robust correlations with index parameters. The resulting information is incorporated into a tool for optimal field characterization and parameter selection with uncertainty analyses. Ultimately, the project develops a borehole tool for the comprehensive characterization of hydrate-bearing sediments at in situ, with the design recognizing past developments and characterization experience and benefited from the inspiration of nature and sensor miniaturization.

Raman spectroscopy for characterization of annealing of ion-implanted InP

International Nuclear Information System (INIS)

Myers, D.R.; Gourley, P.L.; Vaidyanathan, K.V.; Dunlap, H.L.

1983-01-01

Raman spectroscopy has been used as a noncontacting, nondestructive tool to evaluate the properties of Si + - and Be + implanted InP samples annealed at temperatures ranging from 600 to 750C using phospho-silicate glass (PSG) as the encapsulant. Carrier activation, carrier mobility and recovery of damage as a function of anneal temperature obtained from analysis of Raman data agree very well with independent electrical measurements. (author)

Standardizing Exoplanet Analysis with the Exoplanet Characterization Tool Kit (ExoCTK)

Science.gov (United States)

Fowler, Julia; Stevenson, Kevin B.; Lewis, Nikole K.; Fraine, Jonathan D.; Pueyo, Laurent; Bruno, Giovanni; Filippazzo, Joe; Hill, Matthew; Batalha, Natasha; Wakeford, Hannah; Bushra, Rafia

2018-06-01

Exoplanet characterization depends critically on analysis tools, models, and spectral libraries that are constantly under development and have no single source nor sense of unified style or methods. The complexity of spectroscopic analysis and initial time commitment required to become competitive is prohibitive to new researchers entering the field, as well as a remaining obstacle for established groups hoping to contribute in a comparable manner to their peers. As a solution, we are developing an open-source, modular data analysis package in Python and a publicly facing web interface including tools that address atmospheric characterization, transit observation planning with JWST, JWST corongraphy simulations, limb darkening, forward modeling, and data reduction, as well as libraries of stellar, planet, and opacity models. The foundation of these software tools and libraries exist within pockets of the exoplanet community, but our project will gather these seedling tools and grow a robust, uniform, and well-maintained exoplanet characterization toolkit.

Current research relevant to the improvement of γ-ray spectroscopy as an analytical tool

International Nuclear Information System (INIS)

Meyer, R.A.; Tirsell, K.G.; Armantrout, G.A.

1976-01-01

Four areas of research that will have significant impact on the further development of γ-ray spectroscopy as an accurate analytical tool are considered. The areas considered are: (1) automation; (2) accurate multigamma ray sources; (3) accuracy of the current and future γ-ray energy scale, and (4) new solid state X and γ-ray detectors

Designing tools for oil exploration using nuclear modeling

Science.gov (United States)

Mauborgne, Marie-Laure; Allioli, Françoise; Manclossi, Mauro; Nicoletti, Luisa; Stoller, Chris; Evans, Mike

2017-09-01

When designing nuclear tools for oil exploration, one of the first steps is typically nuclear modeling for concept evaluation and initial characterization. Having an accurate model, including the availability of accurate cross sections, is essential to reduce or avoid time consuming and costly design iterations. During tool response characterization, modeling is benchmarked with experimental data and then used to complement and to expand the database to make it more detailed and inclusive of more measurement environments which are difficult or impossible to reproduce in the laboratory. We present comparisons of our modeling results obtained using the ENDF/B-VI and ENDF/B-VII cross section data bases, focusing on the response to a few elements found in the tool, borehole and subsurface formation. For neutron-induced inelastic and capture gamma ray spectroscopy, major obstacles may be caused by missing or inaccurate cross sections for essential materials. We show examples of the benchmarking of modeling results against experimental data obtained during tool characterization and discuss observed discrepancies.

Two-dimensional NMR spectroscopy as a tool to link soil organic matter composition to ecosystem processes

Science.gov (United States)

Soucemarianadin, Laure; Erhagen, Björn; Öquist, Mats; Nilsson, Mats; Schleucher, Jürgen

2014-05-01

Environmental factors (e.g. temperature and moisture) and the size and composition of soil microbial populations are often considered the main drivers of soil organic matter (SOM) mineralization. Less consideration is given to the role of SOM as a substrate for microbial metabolism and the importance of the organo-chemical composition of SOM on decomposition. In addition, a fraction of the SOM is often considered as recalcitrant to mineralization leading to accumulation of SOM. However, recently the concept of intrinsic recalcitrance of SOM to mineralization has been questioned. The challenge in investigating the role of SOM composition on its mineralization to a large extent stems from the difficulties in obtaining high resolution characterization of a very complex matrix. 13C nuclear magnetic resonance (NMR) spectroscopy is a widely used tool to characterize SOM. However, SOM is a very complex mixture and in the resulting 13C NMR spectra, the identified functional groups may represent different molecular fragments that appear in the same spectral region leading to broad peaks. These overlaps defy attempts to identify molecular moieties, and this makes it impossible to derive information at a resolution needed for evaluating e.g. recalcitrance of SOM. Here we applied a method, developed in wood science for the pulp paper industry, to achieve a better characterization of SOM. We directly dissolved finely ground organic layers of boreal forest floors-litters, fibric and humic horizons of both coniferous and broadleaved stands-in dimethyl sulfoxide and analyzed the resulting solution with a two-dimensional (2D) 1H-13C NMR experiment. We will discuss methodological aspects related to the ability to identify and quantify individual molecular moieties in SOM. We will demonstrate how the spectra resolve signals of CH groups in a 2D plane determined by the 13C and 1H chemical shifts, thereby vastly increasing the resolving power and information content of NMR spectra. The

Fourier transform infrared spectroscopy in physics laboratory courses

International Nuclear Information System (INIS)

Möllmann, K-P; Vollmer, M

2013-01-01

Infrared spectrometry is one of the most important tools in the field of spectroscopic analysis. This is due to the high information content of spectra in the so-called spectroscopic fingerprint region, which enables measurement not only of gases, but also of liquids and solids. Today, infrared spectroscopy is almost completely dominated by Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy is able to detect minute quantities in the ppm and ppb ranges, and the respective analyses are now standard tools in science as well as industry. Therefore FTIR spectroscopy should be taught within the standard curriculum at university to physicists and engineers. Here we present respective undergraduate laboratory experiments designed for students at the end of their third year. Experiments deal first with understanding the spectrometer and second with recording and analysing spectra. On the one hand, transmission spectra of gases are treated which relate to environmental analytics (being probably the most prominent and well-known examples), and on the other hand, the focus is on the transmission and reflection spectra of solids. In particular, silicon wafers are studied—as is regularly done in the microelectronics industry—in order to characterize their thickness, oxygen content and phonon modes. (paper)

Characterization of Crystal Chirality in Amino Acids Using Low-Frequency Raman Spectroscopy.

Science.gov (United States)

Aviv, Hagit; Nemtsov, Irena; Mastai, Yitzhak; Tischler, Yaakov R

2017-10-19

We present a new method for differentiating racemic crystals from enantiopure crystals. Recently, developments in optical filters have enabled the facile use of Raman spectroscopy to detect low-frequency vibrational (LFV) modes. Here, for the first time, we use Raman spectroscopy to characterize the LFV modes for crystalline organic materials composed of chiral molecules. The LF-Raman spectra of racemic and enantiopure crystals exhibit a significant variation, which we attribute to different hydrogen-bond networks in the chiral crystal structures. Across a representative set of amino acids, we observed that when comparing racemic versus enantiopure crystals, the available LFV modes and their relative scattering intensity are strong functions of side chain polarity. Thus, LF-Raman can be used as a method that is complementary to the currently used methods for characterizing crystal chirality due to simpler, faster, and more sensitive measurements, along with the small sample size required, which is limited by the laser-beam diameter in the focus.

ASPECT (Automated System-level Performance Evaluation and Characterization Tool), Phase II

Data.gov (United States)

National Aeronautics and Space Administration — SSCI has developed a suite of SAA tools and an analysis capability referred to as ASPECT (Automated System-level Performance Evaluation and Characterization Tool)....

Polymorph characterization of active pharmaceutical ingredients (APIs) using low-frequency Raman spectroscopy.

Science.gov (United States)

Larkin, Peter J; Dabros, Marta; Sarsfield, Beth; Chan, Eric; Carriere, James T; Smith, Brian C

2014-01-01

Polymorph detection, identification, and quantitation in crystalline materials are of great importance to the pharmaceutical industry. Vibrational spectroscopic techniques used for this purpose include Fourier transform mid-infrared (FT-MIR) spectroscopy, Fourier transform near-infrared (FT-NIR) spectroscopy, Raman spectroscopy, and terahertz (THz) and far-infrared (FIR) spectroscopy. Typically, the fundamental molecular vibrations accessed using high-frequency Raman and MIR spectroscopy or the overtone and combination of bands in the NIR spectra are used to monitor the solid-state forms of active pharmaceutical ingredients (APIs). The local environmental sensitivity of the fundamental molecular vibrations provides an indirect probe of the long-range order in molecular crystals. However, low-frequency vibrational spectroscopy provides access to the lattice vibrations of molecular crystals and, hence, has the potential to more directly probe intermolecular interactions in the solid state. Recent advances in filter technology enable high-quality, low-frequency Raman spectra to be acquired using a single-stage spectrograph. This innovation enables the cost-effective collection of high-quality Raman spectra in the 200-10 cm(-1) region. In this study, we demonstrate the potential of low-frequency Raman spectroscopy for the polymorphic characterization of APIs. This approach provides several benefits over existing techniques, including ease of sampling and more intense, information-rich band structures that can potentially discriminate among crystalline forms. An improved understanding of the relationship between the crystalline structure and the low-frequency vibrational spectrum is needed for the more widespread use of the technique.

Single-Crystalline cooperite (PtS): Crystal-Chemical characterization, ESR spectroscopy, and {sup 195}Pt NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Rozhdestvina, V. I., E-mail: veronika@ascnet.ru; Ivanov, A. V.; Zaremba, M. A. [Far East Division, Russian Academy of Sciences, Institute of Geology and Nature Management (Russian Federation); Antsutkin, O. N.; Forsling, W. [Lulea University of Technology (Sweden)

2008-05-15

Single-crystalline cooperite (PtS) with a nearly stoichiometric composition was characterized in detail by X-ray diffraction, electron-probe X-ray microanalysis, and high-resolution scanning electron microscopy. For the first time it was demonstrated that {sup 195}Pt static and MAS NMR spectroscopy can be used for studying natural platinum minerals. The {sup 195}Pt chemical-shift tensor of cooperite was found to be consistent with the axial symmetry and is characterized by the following principal values: {delta}{sub xx} = -5920 ppm, {delta}{sub yy} = -3734 ppm, {delta}{sub zz} = +4023 ppm, and {delta}{sub iso} = -1850 ppm. According to the ESR data, the samples of cooperite contain copper(II), which is adsorbed on the surface during the layer-by-layer crystal growth and is not involved in the crystal lattice.

Characterizing millisecond intermediates in hemoproteins using rapid-freeze-quench resonance Raman spectroscopy.

Science.gov (United States)

Matsumura, Hirotoshi; Moënne-Loccoz, Pierre

2014-01-01

The combination of rapid freeze quenching (RFQ) with resonance Raman (RR) spectroscopy represents a unique tool with which to investigate the nature of short-lived intermediates formed during the enzymatic reactions of metalloproteins. Commercially available equipment allows trapping of intermediates within a millisecond to second time scale for low-temperature RR analysis resulting in the direct detection of metal-ligand vibrations and porphyrin skeletal vibrations in hemoproteins. This chapter briefly discusses RFQ-RR studies carried out previously in our laboratory and presents, as a practical example, protocols for the preparation of RFQ samples of the reaction of metmyoglobin with nitric oxide (NO) under anaerobic conditions. Also described are important controls and practical procedures for the analysis of these samples by low-temperature RR spectroscopy.

Materials characterization of free volume and void properties by two-dimensional positron annihilation lifetime spectroscopy

Science.gov (United States)

Chen, Hongmin; Van Horn, J. David; Jean, Y. C.; Hung, Wei-Song; Lee, Kueir-Rarn

2013-04-01

Positron annihilation lifetime spectroscopy (PALS) has been widely used to determine the free volume and void properties in polymeric materials. Recently, a two dimensional positron annihilation lifetime spectroscopy (2DPALS) system has been developed for membrane applications. The system measures the coincident signals between the lifetime and the energy which could separate the 2γ and 3γ annihilations and improve the accuracy in the determination of the free volume and void properties. When 2D-PALS is used in coupling with a variable mono-energy slow positron beam, it could be applied to a variety of material characterization. Results of free volumes and voids properties in a multi-layer polymer membrane characterized using 2D-PALS are presented.

Vibrational spectroscopy: a clinical tool for cancer diagnostics.

Science.gov (United States)

Kendall, Catherine; Isabelle, Martin; Bazant-Hegemark, Florian; Hutchings, Joanne; Orr, Linda; Babrah, Jaspreet; Baker, Rebecca; Stone, Nicholas

2009-06-01

Vibrational spectroscopy techniques have demonstrated potential to provide non-destructive, rapid, clinically relevant diagnostic information. Early detection is the most important factor in the prevention of cancer. Raman and infrared spectroscopy enable the biochemical signatures from biological tissues to be extracted and analysed. In conjunction with advanced chemometrics such measurements can contribute to the diagnostic assessment of biological material. This paper also illustrates the complementary advantage of using Raman and FTIR spectroscopy technologies together. Clinical requirements are increasingly met by technological developments which show promise to become a clinical reality. This review summarises recent advances in vibrational spectroscopy and their impact on the diagnosis of cancer.

Designing tools for oil exploration using nuclear modeling

Directory of Open Access Journals (Sweden)

Mauborgne Marie-Laure

2017-01-01

Full Text Available When designing nuclear tools for oil exploration, one of the first steps is typically nuclear modeling for concept evaluation and initial characterization. Having an accurate model, including the availability of accurate cross sections, is essential to reduce or avoid time consuming and costly design iterations. During tool response characterization, modeling is benchmarked with experimental data and then used to complement and to expand the database to make it more detailed and inclusive of more measurement environments which are difficult or impossible to reproduce in the laboratory. We present comparisons of our modeling results obtained using the ENDF/B-VI and ENDF/B-VII cross section data bases, focusing on the response to a few elements found in the tool, borehole and subsurface formation. For neutron-induced inelastic and capture gamma ray spectroscopy, major obstacles may be caused by missing or inaccurate cross sections for essential materials. We show examples of the benchmarking of modeling results against experimental data obtained during tool characterization and discuss observed discrepancies.

Laser induced breakdown spectroscopy (LIBS) as a rapid tool for material analysis

International Nuclear Information System (INIS)

Hussain, T; Gondal, M A

2013-01-01

Laser induced breakdown spectroscopy (LIBS) is a novel technique for elemental analysis based on laser-generated plasma. In this technique, laser pulses are applied for ablation of the sample, resulting in the vaporization and ionization of sample in hot plasma which is finally analyzed by the spectrometer. The elements are identified by their unique spectral signatures. LIBS system was developed for elemental analysis of solid and liquid samples. The developed system was applied for qualitative as well as quantitative measurement of elemental concentration present in iron slag and open pit ore samples. The plasma was generated by focusing a pulsed Nd:YAG laser at 1064 nm on test samples to study the capabilities of LIBS as a rapid tool for material analysis. The concentrations of various elements of environmental significance such as cadmium, calcium, magnesium, chromium, manganese, titanium, barium, phosphorus, copper, iron, zinc etc., in these samples were determined. Optimal experimental conditions were evaluated for improving the sensitivity of developed LIBS system through parametric dependence study. The laser-induced breakdown spectroscopy (LIBS) results were compared with the results obtained using standard analytical technique such as inductively couple plasma emission spectroscopy (ICP). Limit of detection (LOD) of our LIBS system were also estimated for the above mentioned elements. This study demonstrates that LIBS could be highly appropriate for rapid online analysis of iron slag and open pit waste.

Laser induced breakdown spectroscopy (LIBS) as a rapid tool for material analysis

Science.gov (United States)

Hussain, T.; Gondal, M. A.

2013-06-01

Laser induced breakdown spectroscopy (LIBS) is a novel technique for elemental analysis based on laser-generated plasma. In this technique, laser pulses are applied for ablation of the sample, resulting in the vaporization and ionization of sample in hot plasma which is finally analyzed by the spectrometer. The elements are identified by their unique spectral signatures. LIBS system was developed for elemental analysis of solid and liquid samples. The developed system was applied for qualitative as well as quantitative measurement of elemental concentration present in iron slag and open pit ore samples. The plasma was generated by focusing a pulsed Nd:YAG laser at 1064 nm on test samples to study the capabilities of LIBS as a rapid tool for material analysis. The concentrations of various elements of environmental significance such as cadmium, calcium, magnesium, chromium, manganese, titanium, barium, phosphorus, copper, iron, zinc etc., in these samples were determined. Optimal experimental conditions were evaluated for improving the sensitivity of developed LIBS system through parametric dependence study. The laser-induced breakdown spectroscopy (LIBS) results were compared with the results obtained using standard analytical technique such as inductively couple plasma emission spectroscopy (ICP). Limit of detection (LOD) of our LIBS system were also estimated for the above mentioned elements. This study demonstrates that LIBS could be highly appropriate for rapid online analysis of iron slag and open pit waste.

Synthesis, Characterization, and Spectroscopy of Model Molybdopterin Complexes‡

Science.gov (United States)

Burgmayer, Sharon J. Nieter; Kim, Mary; Petit, Rebecca; Rothkopf, Amy; Kim, Alison; BelHamdounia, Shadia; Hou, Ying; Somogyi, Arpad; Habel-Rodriguez, Diana; Williams, Antonio; Kirk, Martin L.

2012-01-01

The preparation and characterization of new model complexes for the molybdenum cofactor are reported. The new models are distinctive for the inclusion of pterin-substituted dithiolene chelates and have the formulation Tp*MoX(pterin-R-dithiolene) (Tp* = tris(3,5,-dimethylpyrazolyl)borate), X= O, S, R= aryl or −C(OH)(CH3)2). Syntheses of Mo(4+) and (5+) complexes of two pterin-dithiolene derivatives as both oxo and sulfido compounds, and improved syntheses for pterinyl alkynes and [Et4N][Tp*MoIV(S)S4] reagents are described. Characterization methods include electrospray ionization mass spectrometry, electrochemistry, infrared spectroscopy, electron paramagnetic resonance and magnetic circular dichroism. Cyclic voltammetry reveals that the Mo(5+/4+) reduction potential is intermediate between that for dithiolene with electron-withdrawing substituents and simple dithiolate chelates. Electron paramagnetic resonance and magnetic circular dichroism of Mo(5+) complexes where X = O, R = aryl indicates that the molybdenum environment in the new models is electronically similar to that in Tp*MoO(benzenedithiolate). PMID:17765313

Validating the Melusine Gamma Spectroscopy Tool

Energy Technology Data Exchange (ETDEWEB)

Erikson, Luke E.; Keillor, Martin E.; Stavenger, Timothy J.

2013-11-26

This technical report describes testing to evaluate the gamma spectroscopy tool, Melusine, under development by Pacific Northwest National Laboratory. The goal was to verify that the software can successfully be used to provide accurate results and statistical uncertainties for the detection of isotopes of interest and their activities. Of special interest were spectra similar to those produced by radionuclide stations that contribute to the Comprehensive Nuclear Test Ban Treaty Organization’s International Monitoring System. Two data sets were used to test Melusine’s capabilities. The first was the result of a multi-lab calibration effort based on neutron activations produced at the University of California at Davis. The second was taken from the Proficiency Test Exercises conducted by the CTBTO directly in 2005. In 37 of 42 cases, Melusine produced results in agreement with the best answer presently available, in most cases with calculated uncertainties comparable to or better than competing analyses. In fact, Melusine technically provided one more result than CTBTO’s PTE analyses that agreed with the “book answer” (Monte Carlo simulation). Despite these promising results, the Melusine software is still under development. Effort is especially needed to simplify its analysis process, improve stability, and provide user documentation. Some significant analysis tasks require further vetting, such as those to address summing effects. However, our test results indicate that Melusine’s calculations as presently implemented are sound and can be used to reliably analyze spectra from the CTBTO’s radionuclide stations.

Characterization of lipid oxidation process of beef during repeated freeze-thaw by electron spin resonance technology and Raman spectroscopy.

Science.gov (United States)

Chen, Qingmin; Xie, Yunfei; Xi, Jinzhong; Guo, Yahui; Qian, He; Cheng, Yuliang; Chen, Yi; Yao, Weirong

2018-03-15

In this study, electron spin resonance (ESR) and Raman spectroscopy were applied to characterize lipid oxidation of beef during repeated freeze-thaw (RFT). Besides the conventional indexes including peroxide values (PV), thiobarbituric acid-reactive substances (TBARS) and acid values (AV) were evaluated, the radical and molecular structure changes were also measured by ESR and Raman spectroscopy. The results showed that PV, TBARS and AV were increased (PRaman intensity of ν(CC) stretching region (1655cm -1 ) was decreased during RFT. Furthermore, lower Raman intensity ratio of I 1655 /I 1442 , I 1655 /I 1745 that determine total unsaturation was also observed. Significant correlations (pRaman spectroscopy. Our result has proved that ESR and Raman spectroscopy showed great potential in characterizing lipid oxidation process of beef during RFT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fluorescence spectroscopy

DEFF Research Database (Denmark)

Bagatolli, Luis

2016-01-01

Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses the foundati......Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

Magnetic resonance spectroscopy (MRS) of vertebral column – an additional tool for evaluation of aggressiveness of vertebral haemangioma like lesion

International Nuclear Information System (INIS)

Jeromel, Miran; Podobnik, Janez

2014-01-01

Most vertebral haemangioma are asymptomatic and discovered incidentally. Sometimes the symptomatic lesions present with radiological signs of aggressiveness and their appearance resemble other aggressive lesions (e.g. solitary plasmacytoma). We present a patient with large symptomatic aggressive haemangioma like lesion in 12 th thoracic vertebra in which a magnetic resonance spectroscopy (MRS) was used to analyse fat content within the lesion. The lesion in affected vertebrae showed low fat content with 33% of fat fraction (%FF). The fat content in non-affected (1 st lumbar) vertebra was as expected for patient’s age (68%). Based on MRS data, the lesion was characterized as an aggressive haemangioma. The diagnosis was confirmed with biopsy, performed during the treatment – percutaneous vertebroplasty. The presented case shows that MRS can be used as an additional tool for evaluation of aggressiveness of vertebral haemangioma like lesions

Prediction of the wear and evolution of cutting tools in a carbide / titanium-aluminum-vanadium machining tribosystem by volumetric tool wear characterization and modeling

Science.gov (United States)

Kuttolamadom, Mathew Abraham

The objective of this research work is to create a comprehensive microstructural wear mechanism-based predictive model of tool wear in the tungsten carbide / Ti-6Al-4V machining tribosystem, and to develop a new topology characterization method for worn cutting tools in order to validate the model predictions. This is accomplished by blending first principle wear mechanism models using a weighting scheme derived from scanning electron microscopy (SEM) imaging and energy dispersive x-ray spectroscopy (EDS) analysis of tools worn under different operational conditions. In addition, the topology of worn tools is characterized through scanning by white light interferometry (WLI), and then application of an algorithm to stitch and solidify data sets to calculate the volume of the tool worn away. The methodology was to first combine and weight dominant microstructural wear mechanism models, to be able to effectively predict the tool volume worn away. Then, by developing a new metrology method for accurately quantifying the bulk-3D wear, the model-predicted wear was validated against worn tool volumes obtained from corresponding machining experiments. On analyzing worn crater faces using SEM/EDS, adhesion was found dominant at lower surface speeds, while dissolution wear dominated with increasing speeds -- this is in conformance with the lower relative surface speed requirement for micro welds to form and rupture, essentially defining the mechanical load limit of the tool material. It also conforms to the known dominance of high temperature-controlled wear mechanisms with increasing surface speed, which is known to exponentially increase temperatures especially when machining Ti-6Al-4V due to its low thermal conductivity. Thus, straight tungsten carbide wear when machining Ti-6Al-4V is mechanically-driven at low surface speeds and thermally-driven at high surface speeds. Further, at high surface speeds, craters were formed due to carbon diffusing to the tool surface and

Characterization of full set material constants of piezoelectric materials based on ultrasonic method and inverse impedance spectroscopy using only one sample.

Science.gov (United States)

Li, Shiyang; Zheng, Limei; Jiang, Wenhua; Sahul, Raffi; Gopalan, Venkatraman; Cao, Wenwu

2013-09-14

The most difficult task in the characterization of complete set material properties for piezoelectric materials is self-consistency. Because there are many independent elastic, dielectric, and piezoelectric constants, several samples are needed to obtain the full set constants. Property variation from sample to sample often makes the obtained data set lack of self-consistency. Here, we present a method, based on pulse-echo ultrasound and inverse impedance spectroscopy, to precisely determine the full set physical properties of piezoelectric materials using only one small sample, which eliminated the sample to sample variation problem to guarantee self-consistency. The method has been applied to characterize the [001] C poled Mn modified 0.27Pb(In 1/2 Nb 1/2 )O 3 -0.46Pb(Mg 1/3 Nb 2/3 )O 3 -0.27PbTiO 3 single crystal and the validity of the measured data is confirmed by a previously established method. For the inverse calculations using impedance spectrum, the stability of reconstructed results is analyzed by fluctuation analysis of input data. In contrast to conventional regression methods, our method here takes the full advantage of both ultrasonic and inverse impedance spectroscopy methods to extract all constants from only one small sample. The method provides a powerful tool for assisting novel piezoelectric materials of small size and for generating needed input data sets for device designs using finite element simulations.

Versatile silicon-waveguide supercontinuum for coherent mid-infrared spectroscopy

Science.gov (United States)

Nader, Nima; Maser, Daniel L.; Cruz, Flavio C.; Kowligy, Abijith; Timmers, Henry; Chiles, Jeff; Fredrick, Connor; Westly, Daron A.; Nam, Sae Woo; Mirin, Richard P.; Shainline, Jeffrey M.; Diddams, Scott

2018-03-01

Laser frequency combs, with their unique combination of precisely defined spectral lines and broad bandwidth, are a powerful tool for basic and applied spectroscopy. Here, we report offset-free, mid-infrared frequency combs and dual-comb spectroscopy through supercontinuum generation in silicon-on-sapphire waveguides. We leverage robust fabrication and geometrical dispersion engineering of nanophotonic waveguides for multi-band, coherent frequency combs spanning 70 THz in the mid-infrared (2.5 μm-6.2 μm). Precise waveguide fabrication provides significant spectral broadening with engineered spectra targeted at specific mid-infrared bands. We characterize the relative-intensity-noise of different bands and show that the measured levels do not pose any limitation for spectroscopy applications. Additionally, we use the fabricated photonic devices to demonstrate dual-comb spectroscopy of a carbonyl sulfide gas sample at 5 μm. This work forms the technological basis for applications such as point sensors for fundamental spectroscopy, atmospheric chemistry, trace and hazardous gas detection, and biological microscopy.

Versatile silicon-waveguide supercontinuum for coherent mid-infrared spectroscopy

Directory of Open Access Journals (Sweden)

Nima Nader

2018-03-01

Full Text Available Laser frequency combs, with their unique combination of precisely defined spectral lines and broad bandwidth, are a powerful tool for basic and applied spectroscopy. Here, we report offset-free, mid-infrared frequency combs and dual-comb spectroscopy through supercontinuum generation in silicon-on-sapphire waveguides. We leverage robust fabrication and geometrical dispersion engineering of nanophotonic waveguides for multi-band, coherent frequency combs spanning 70 THz in the mid-infrared (2.5 μm–6.2 μm. Precise waveguide fabrication provides significant spectral broadening with engineered spectra targeted at specific mid-infrared bands. We characterize the relative-intensity-noise of different bands and show that the measured levels do not pose any limitation for spectroscopy applications. Additionally, we use the fabricated photonic devices to demonstrate dual-comb spectroscopy of a carbonyl sulfide gas sample at 5 μm. This work forms the technological basis for applications such as point sensors for fundamental spectroscopy, atmospheric chemistry, trace and hazardous gas detection, and biological microscopy.

Moessbauer spectroscopy characterization of Zr-Nb-Fe phases

Energy Technology Data Exchange (ETDEWEB)

Ramos, C.P. [CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)]. E-mail: ciramos@cnea.gov.ar; Granovsky, M.S. [CAC-CNEA, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Saragovi, C. [CAC-CNEA, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)

2007-02-01

The aim of this work was the characterization of the ternary phases and of those coming from the corresponding binary systems in the Zr-Nb-Fe diagram by means of Moessbauer spectroscopy. This is part of a complete study involving a tentative isothermal section at 900 deg. C of the center of the Zr-Nb-Fe diagram which will be published elsewhere. Zr-Nb-Fe alloys with Nb contents between 5 and 50 at% and Fe contents between 10 and 60 at% were analyzed after a heat treatment at 900 deg. C for 4 month. Moessbauer characterization of the phases was complemented by optical and scanning electron microscopies, X-ray diffraction and electron microprobe analysis. From the obtained results it can be inferred that Fe in both of the Laves phases present in this system (Zr(FeNb){sub 2} and (ZrNb)Fe{sub 2}) sees different environments, producing quadrupole splitting and hyperfine field distributions, respectively. Two types of body centered cubic {beta} phases (Zr-rich and Nb-rich) were found having noticeable differences in their Moessbauer parameters. Furthermore it was shown that the ternary Fe(NbZr){sub 2} compound would show magnetic character at low temperatures. Concentration dependence of the hyperfine parameters and their relations with the lattice parameters contributed to the structural characterization of the phases.

Moessbauer spectroscopy characterization of Zr-Nb-Fe phases

International Nuclear Information System (INIS)

Ramos, C.P.; Granovsky, M.S.; Saragovi, C.

2007-01-01

The aim of this work was the characterization of the ternary phases and of those coming from the corresponding binary systems in the Zr-Nb-Fe diagram by means of Moessbauer spectroscopy. This is part of a complete study involving a tentative isothermal section at 900 deg. C of the center of the Zr-Nb-Fe diagram which will be published elsewhere. Zr-Nb-Fe alloys with Nb contents between 5 and 50 at% and Fe contents between 10 and 60 at% were analyzed after a heat treatment at 900 deg. C for 4 month. Moessbauer characterization of the phases was complemented by optical and scanning electron microscopies, X-ray diffraction and electron microprobe analysis. From the obtained results it can be inferred that Fe in both of the Laves phases present in this system (Zr(FeNb) 2 and (ZrNb)Fe 2 ) sees different environments, producing quadrupole splitting and hyperfine field distributions, respectively. Two types of body centered cubic β phases (Zr-rich and Nb-rich) were found having noticeable differences in their Moessbauer parameters. Furthermore it was shown that the ternary Fe(NbZr) 2 compound would show magnetic character at low temperatures. Concentration dependence of the hyperfine parameters and their relations with the lattice parameters contributed to the structural characterization of the phases

Characterization of organic photovoltaic devices using femtosecond laser induced breakdown spectroscopy

Science.gov (United States)

Banerjee, S. P.; Sarnet, Thierry; Siozos, Panayiotis; Loulakis, Michalis; Anglos, Demetrios; Sentis, Marc

2017-10-01

The potential of laser induced breakdown spectroscopy (LIBS) as a non-contact probe, for characterizing organic photovoltaic devices during selective laser scribing, was investigated. Samples from organic solar cells were studied, which consisted of several layers of materials including a top electrode (Al, Mg or Mo), organic layer, bottom electrode (indium tin oxide), silicon nitride barrier layer and substrate layer situated from the top consecutively. The thickness of individual layers varies from 115 to 250 nm. LIBS measurements were performed by use of a 40 femtosecond Ti:Sapphire laser operated at very low pulse energy (solar cell structure, demonstrating the potential of LIBS for fast, non-contact characterization of organic photovoltaic coatings.

Line and continuum spectroscopy as diagnostic tools for gamma ray bursts

International Nuclear Information System (INIS)

Liang, E.P.

1990-12-01

We review the theoretical framework of both line and continuum spectra formation in gamma ray bursts. These include the cyclotron features at 10's of keV, redshifted annihilation features at ∼400 keV, as well as other potentially detectable nuclear transition lines, atomic x-ray lines, proton cyclotron lines and plasma oscillation lines. By combining the parameters derived from line and continuum modeling we can try to reconstruct the location, geometry and physical conditions of the burst emission region, thereby constraining and discriminating the astrophysical models. Hence spectroscopy with current and future generations of detectors should provide powerful diagnostic tools for gamma ray bursters. 48 refs., 10 figs., 4 tabs

Characterization of photo-induced valence tautomerism in a cobalt-dioxolene complex by ultrafast spectroscopy

International Nuclear Information System (INIS)

Beni, A; Bogani, L; Bussotti, L; Dei, A; Gentili, P L; Righini, R

2005-01-01

The valence tautomerism of low-spin Co III (Cat-N-BQ)(Cat-N-SQ) was investigated by means of UV-vis pump-probe transient absorption spectroscopy in chloroform. By exciting the CT transition of the complex at 480 nm, an intramolecular electron transfer process is selectively triggered. The photo-induced charge transfer is pursued by a cascade of two main molecular events characterized by the ultrafast transient absorption spectroscopy: the first gives rise to the metastable high-spin Co II (Cat-N-BQ) 2 that, secondly, reaches the chemical equilibrium with the reactant species

Characterization of photo-induced valence tautomerism in a cobalt-dioxolene complex by ultrafast spectroscopy

Science.gov (United States)

Beni, A.; Bogani, L.; Bussotti, L.; Dei, A.; Gentili, P. L.; Righini, R.

2005-01-01

The valence tautomerism of low-spin CoIII(Cat-N-BQ)(Cat-N-SQ) was investigated by means of UV-vis pump-probe transient absorption spectroscopy in chloroform. By exciting the CT transition of the complex at 480 nm, an intramolecular electron transfer process is selectively triggered. The photo-induced charge transfer is pursued by a cascade of two main molecular events characterized by the ultrafast transient absorption spectroscopy: the first gives rise to the metastable high-spin CoII(Cat-N-BQ)2 that, secondly, reaches the chemical equilibrium with the reactant species.

Metabolomics As a Tool for the Characterization of Drug-Resistant Epilepsy.

Science.gov (United States)

Murgia, Federica; Muroni, Antonella; Puligheddu, Monica; Polizzi, Lorenzo; Barberini, Luigi; Orofino, Gianni; Solla, Paolo; Poddighe, Simone; Del Carratore, Francesco; Griffin, Julian L; Atzori, Luigi; Marrosu, Francesco

2017-01-01

Drug resistance is a critical issue in the treatment of epilepsy, contributing to clinical emergencies and increasing both serious social and economic burdens on the health system. The wide variety of potential drug combinations followed by often failed consecutive attempts to match drugs to an individual patient may mean that this treatment stage may last for years with suboptimal benefit to the patient. Given these challenges, it is valuable to explore the availability of new methodologies able to shorten the period of determining a rationale pharmacologic treatment. Metabolomics could provide such a tool to investigate possible markers of drug resistance in subjects with epilepsy. Blood samples were collected from (1) controls (C) ( n  = 35), (2) patients with epilepsy "responder" (R) ( n  = 18), and (3) patients with epilepsy "non-responder" (NR) ( n  = 17) to the drug therapy. The samples were analyzed using nuclear magnetic resonance spectroscopy, followed by multivariate statistical analysis. A different metabolic profile based on metabolomics analysis of the serum was observed between C and patients with epilepsy and also between R and NR patients. It was possible to identify the discriminant metabolites for the three classes under investigation. Serum from patients with epilepsy were characterized by increased levels of 3-OH-butyrate, 2-OH-valerate, 2-OH-butyrate, acetoacetate, acetone, acetate, choline, alanine, glutamate, scyllo-inositol (C lactate, and citrate compared to C (C > R > NR). In conclusion, metabolomics may represent an important tool for discovery of differences between subjects affected by epilepsy responding or resistant to therapies and for the study of its pathophysiology, optimizing the therapeutic resources and the quality of life of patients.

Arduino Due based tool to facilitate in vivo two-photon excitation microscopy.

Science.gov (United States)

Artoni, Pietro; Landi, Silvia; Sato, Sebastian Sulis; Luin, Stefano; Ratto, Gian Michele

2016-04-01

Two-photon excitation spectroscopy is a powerful technique for the characterization of the optical properties of genetically encoded and synthetic fluorescent molecules. Excitation spectroscopy requires tuning the wavelength of the Ti:sapphire laser while carefully monitoring the delivered power. To assist laser tuning and the control of delivered power, we developed an Arduino Due based tool for the automatic acquisition of high quality spectra. This tool is portable, fast, affordable and precise. It allowed studying the impact of scattering and of blood absorption on two-photon excitation light. In this way, we determined the wavelength-dependent deformation of excitation spectra occurring in deep tissues in vivo.

Characterization of UO2 by infrared spectroscopy

International Nuclear Information System (INIS)

Faeda, Kelly C.M.; Machado, Geraldo C.; Lameiras, Fernando S.

2011-01-01

The characterization of nuclear fuel is of great importance to minimize the effects related to burnup and temperature and to achieve stability during in-core operation. The understanding the U-O system and its thermodynamic properties has fundamental importance in nuclear industry. Many physical properties of UO 2±x depend on the ratio O / U, such as the electrical conductivity and thermal properties, as well as the diffusivities of its constituents and solutes. The U-O system presents various oxides such as UO 2±x , U 4 O 9 , U 3 O 8 , and UO 3 . The control of the O/U relation is critical to the manufacturing process of UO 2 . In this work, the infrared spectroscopy was used to identify the presence of phases in UO 2 powder samples that cannot be identified by thermogravimetry and X-ray diffraction. (author)

Raman spectroscopy for characterizing and determining the pozzolanic reactivity of fly ashes

Science.gov (United States)

Garg, Nishant

The efficacy and potential of Raman spectroscopy in characterization of a commercial Ordinary Portland Cement (OPC) and three fly ashes (FA's), and their evolving hydration products were studied in this Master's thesis work. While there have been several studies focusing on the application of Raman spectroscopy to synthetic, pure samples, work on commercial cementitious systems is scarce. This work covers this gap by evaluating mixtures containing cements and fly ashes. The study first involved determination followed by establishment of instrumental configuration and testing parameters optimum for studying cementitious materials both in the dry and wet form. It was found that by tweaking several parameters, collection methodologies and analysis techniques, improved, representative and reproducible data could be obtained. Mapping a representative area to determine the spatial distribution and concentration of sulfates and hydroxides on sample surfaces was found to be the most effective way to study these complex and heterogeneous systems. The Raman dry analysis of OPC and three different FA's of varying calcium contents and reactivity was able to identify the major mineralogical phases in these binders and the results were in correlation with the X-ray diffraction data. The observed calcium and sulfate phases and their relative concentration also agreed well with the supplementary compositional data obtained from X-ray fluorescence and Atomic absorption spectrometry. The wet analysis of pastes prepared with 100% OPC and 50%OPC+50%FA(1,2,3) followed the hydration process of the systems for 56 days (0, 0.2, 2, 4, 8, 12, 16, 20, 24, 48, 72 hours, 7, 14, 21, 28, and 56 days). Consistency of trends in the hydration mechanism of such pastes was only obtained when studies were focused on narrow wavenumber ranges: 950--1050 cm-1 for evolution of sulfates and 3600--3700cm-1 for evolution of hydroxides. Gradual disappearance of Gypsum with a parallel formation of Ettringite

Enantioselective silver nanoclusters: Preparation, characterization and photoluminescence spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Farrag, Mostafa, E-mail: mostafafarrag@aun.edu.eg

2016-09-01

Herein, we report a new wet-synthesis method to separate some water-soluble chiral silver nanoclusters with high yield. The cluster material was obtained by the reduction of silver nitrate with NaBH{sub 4} in the presence of three ligands L-penicillamine (L-pen), D-penicillamine (D-pen) and racemic mixture of penicillamine (rac-pen), functioning as capping ligand. For characterizing all silver cluster samples, the particle size was assessed by transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) and their average chemical formula was determined from thermogravimetric analysis (TGA) and elemental analysis (EA). The particles sizes of all three clusters are 2.1 ± 0.2 nm. The optical properties of the samples were studied by four different methods: UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy (PL) and circular dichroism (CD) spectroscopy. The spectra are dominated by the typical and intense plasmon peak at 486 nm accompanied by a small shoulder at 540 nm. Infrared spectroscopy was measured for the free ligand and protected silver nanoclusters, where the disappearance of the S-H vibrational band (2535–2570 cm{sup −1}) in the silver nanoclusters confirmed anchoring of ligand to the cluster surface through the sulfur atom. PL studies yielded the fluorescent properties of the samples. The main focus of this work, however, lies in the chirality of the particles. For all silver clusters CD spectra were recorded. While for clusters capped with one of the two enantiomers (D- or L-form) typical CD spectra were observed, no significant signals were detected for a racemic ligand mixture. Furthermore, silver clusters show quite large asymmetry factors (up to 3 × 10{sup −4}) in comparison to most other ligand protected clusters. These large factors and bands in the visible range of the spectrum suggest a strong chiral induction from the ligand to the metal core. Textural features of the

Applications of Raman spectroscopy to gemology.

Science.gov (United States)

Bersani, Danilo; Lottici, Pier Paolo

2010-08-01

Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals.

Characterization of Colloidal Quantum Dot Ligand Exchange by X-ray Photoelectron Spectroscopy

Science.gov (United States)

Atewologun, Ayomide; Ge, Wangyao; Stiff-Roberts, Adrienne D.

2013-05-01

Colloidal quantum dots (CQDs) are chemically synthesized semiconductor nanoparticles with size-dependent wavelength tunability. Chemical synthesis of CQDs involves the attachment of long organic surface ligands to prevent aggregation; however, these ligands also impede charge transport. Therefore, it is beneficial to exchange longer surface ligands for shorter ones for optoelectronic devices. Typical characterization techniques used to analyze surface ligand exchange include Fourier-transform infrared spectroscopy, x-ray diffraction, transmission electron microscopy, and nuclear magnetic resonance spectroscopy, yet these techniques do not provide a simultaneously direct, quantitative, and sensitive method for evaluating surface ligands on CQDs. In contrast, x-ray photoelectron spectroscopy (XPS) can provide nanoscale sensitivity for quantitative analysis of CQD surface ligand exchange. A unique aspect of this work is that a fingerprint is identified for shorter surface ligands by resolving the regional XPS spectrum corresponding to different types of carbon bonds. In addition, a deposition technique known as resonant infrared matrix-assisted pulsed laser evaporation is used to improve the CQD film uniformity such that stronger XPS signals are obtained, enabling more accurate analysis of the ligand exchange process.

Neuroimaging in Parkinsonism: a study with magnetic resonance and spectroscopy as tools in the differential diagnosis

International Nuclear Information System (INIS)

Vasconcellos, Luiz Felipe Rocha; Novis, Sergio A. Pereira; Rosso, Ana Lucia Z.; Moreira, Denise Madeira

2009-01-01

The differential diagnosis of Parkinsonism based on clinical features, sometimes may be difficult. Diagnostic tests in these cases might be useful, especially magnetic resonance imaging, a noninvasive exam, not as expensive as positron emission tomography, and provides a good basis for anatomical analysis. The magnetic resonance spectroscopy analyzes cerebral metabolism, yielding inconsistent results in parkinsonian disorders. We selected 40 individuals for magnetic resonance imaging and spectroscopy analysis, 12 with Parkinson's disease, 11 with progressive supranuclear palsy, 7 with multiple system atrophy (parkinsonian type), and 10 individuals without any psychiatric or neurological disorders (controls). Clinical scales included Hoenh and Yahr, unified Parkinson's disease rating scale and mini mental status examination. The results showed that patients with Parkinson's disease and controls presented the same aspects on neuroimaging, with few or absence of abnormalities, and supranuclear progressive palsy and multiple system atrophy showed abnormalities, some of which statistically significant. Thus, magnetic resonance imaging and spectroscopy could be useful as a tool in differential diagnosis of Parkinsonism. (author)

Characterization of defects in metals by positron-annihilation spectroscopy

International Nuclear Information System (INIS)

Siegel, R.W.

1981-10-01

The application of positron-annihilation spectroscopy (PAS) to the characterization and study of defects in metals has grown rapidly and increasingly useful in recent years. Owing to the ability of the positron to annihilate from a variety of defect-trapped states in metals, PAS can yield defect-specific information which, by itself or in conjunction with more traditional experimental techniques, has already made a significant impact upon our knowledge regarding lattice defect properties in metals. This has been especially true for vacancy defets, as a result of the positron's affinity for lower-than-average electron-density regions in the metal. The physical basis for the positron annihilation techniques is presented in this paper; and the experimental techniques, lifetime, Doppler broadening, and angular correlation, are briefly described and compared with respect to the information that can be obtained from each of them. A number of examples of the application of PAS to the characterization of atomic defects and their agglomerates are presented. The particular examples, chosen from the areas of equilibrium vacancy formation and atomic-defect recovery, were selected with a view toward elucidating the particular advantages of PAS over more traditional defect-characterization techniques. Limitations of PAS are also pointed out. 98 references

Cell growth characterization using multi-electrode bioimpedance spectroscopy

International Nuclear Information System (INIS)

Lu, Yi-Yu; Huang, Yu-Jie; Cheng, Kuo-Sheng; Huang, Ji-Jer

2013-01-01

Cell growth characterization during culturing is an important issue in a variety of biomedical applications. In this study an electrical bioimpedance spectroscopy-based multi-electrode culture monitoring system was developed to characterize cell growth. A PC12 cell line was cultured for the cell growth study. The bioimpedance variations for PC12 cell growth within the initial 12 h were measured over a range between 1 kHz and 4 MHz at three different medium concentrations. Within this frequency range, the largest bioimpedance value was 1.9 times the smallest bioimpedance value. The phase angle decreased over the range from 1 to 10 kHz when cells were growing. Then, the phase angle approached a constant over the frequency range between 10 kHz and 2 MHz. Thereafter, the phase angle increased rapidly from 20 to 52 degrees during cell culturing between 8 and 12 h at 4 MHz. The maximum cell number after culturing for 12 h increased by 25.8% for the control sites with poly-D-lysine (PDL) pastes. For the normal growth factor, the cell number increased up to 4.78 times from 8 to 12 h, but only 0.96 and 1.60 times for the other two medium growth factors. The correlation coefficients between impedance and cell number were 0.868 (coating with PDL), and 0.836 (without PDL) for the normal concentration medium. Thus, impedance may be used as an index for cell growth characterization. (paper)

Characterization of photo-induced valence tautomerism in a cobalt-dioxolene complex by ultrafast spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Beni, A [Dipartimento di Chimica, Universita di Firenze, via della Lastruccia 3, 50019 Sesto Fiorentino, Florence (Italy); Bogani, L [Dipartimento di Chimica, Universita di Firenze, via della Lastruccia 3, 50019 Sesto Fiorentino, Florence (Italy); Bussotti, L [LENS, Universita di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Florence (Italy); Dei, A [Dipartimento di Chimica, Universita di Firenze, via della Lastruccia 3, 50019 Sesto Fiorentino, Florence (Italy); Gentili, P L [LENS, Universita di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Florence (Italy); Righini, R [Dipartimento di Chimica, Universita di Firenze, via della Lastruccia 3, 50019 Sesto Fiorentino, Florence (Italy)

2005-01-01

The valence tautomerism of low-spin Co{sup III}(Cat-N-BQ)(Cat-N-SQ) was investigated by means of UV-vis pump-probe transient absorption spectroscopy in chloroform. By exciting the CT transition of the complex at 480 nm, an intramolecular electron transfer process is selectively triggered. The photo-induced charge transfer is pursued by a cascade of two main molecular events characterized by the ultrafast transient absorption spectroscopy: the first gives rise to the metastable high-spin Co{sup II}(Cat-N-BQ){sub 2} that, secondly, reaches the chemical equilibrium with the reactant species.

Laser-induced breakdown spectroscopy analysis of asbestos

International Nuclear Information System (INIS)

Caneve, L.; Colao, F.; Fabbri, F.; Fantoni, R.; Spizzichino, V.; Striber, J.

2005-01-01

Laser-induced breakdown spectroscopy was applied to test the possibility of detecting and identifying asbestos in different samples in view of the perspective at field operation without sample preparation which is peculiar to this technique. Several like-resin materials were first investigated by laser-induced breakdown spectroscopy, in order to find an asbestos container assuring safe laboratory operation during the material characterization aimed to identify indicators suitable for a quick identification on field. Successively, spectra of asbestos samples of both in serpentine and amphibole forms were measured and the variability in elemental composition was calculated from the emission spectra. Ratios of intensities of characteristic elements were tested as indicators for asbestos recognition. Laser-induced breakdown spectroscopy results were compared with those obtained by analyzing the same asbestos samples with a scanning electron microscopy equipped with an energy dispersive X-ray spectroscopy, a good correlation was found for Mg/Si and Fe/Si, thus showing the capability of laser-induced breakdown spectroscopy as a diagnostic tool for this category of materials. In particular, it was demonstrated that the method based on two indicators derived from laser-induced breakdown spectroscopy intensity ratios allows to discriminate between asbestos and cements in single shot measurements suitable to field operation

Fast characterization of solid organic waste content with near infrared spectroscopy in anaerobic digestion.

Science.gov (United States)

Charnier, Cyrille; Latrille, Eric; Jimenez, Julie; Lemoine, Margaux; Boulet, Jean-Claude; Miroux, Jérémie; Steyer, Jean-Philippe

2017-01-01

The development of anaerobic digestion involves both co-digestion of solid wastes and optimization of the feeding recipe. Within this context, substrate characterisation is an essential issue. Although it is widely used, the biochemical methane potential is not sufficient to optimize the operation of anaerobic digestion plants. Indeed the biochemical composition in carbohydrates, lipids, proteins and the chemical oxygen demand of the inputs are key parameters for the optimisation of process performances. Here we used near infrared spectroscopy as a robust and less-time consuming tool to predict the solid waste content in carbohydrates, lipids and nitrogen, and the chemical oxygen demand. We built a Partial Least Square regression model with 295 samples and validated it with an independent set of 46 samples across a wide range of solid wastes found in anaerobic digestion units. The standard errors of cross-validation were 90mgO 2 ⋅gTS -1 carbohydrates, 2.5∗10 -2 g⋅gTS -1 lipids, 7.2∗10 -3 g⋅gTS -1 nitrogen and 99mgO 2 ⋅gTS -1 chemical oxygen demand. The standard errors of prediction were 53mgO 2 ⋅gTS -1 carbohydrates, 3.2∗10 -2 g⋅gTS -1 lipids, 8.6∗10 -3 g⋅gTS -1 nitrogen and 83mgO 2 ⋅gTS -1 chemical oxygen demand. These results show that near infrared spectroscopy is a new fast and cost-efficient way to characterize solid wastes content and improve their anaerobic digestion monitoring. Copyright © 2016 Elsevier Ltd. All rights reserved.

New PLS analysis approach to wine volatile compounds characterization by near infrared spectroscopy (NIR).

Science.gov (United States)

Genisheva, Z; Quintelas, C; Mesquita, D P; Ferreira, E C; Oliveira, J M; Amaral, A L

2018-04-25

This work aims to explore the potential of near infrared (NIR) spectroscopy to quantify volatile compounds in Vinho Verde wines, commonly determined by gas chromatography. For this purpose, 105 Vinho Verde wine samples were analyzed using Fourier transform near infrared (FT-NIR) transmission spectroscopy in the range of 5435 cm -1 to 6357 cm -1 . Boxplot and principal components analysis (PCA) were performed for clusters identification and outliers removal. A partial least square (PLS) regression was then applied to develop the calibration models, by a new iterative approach. The predictive ability of the models was confirmed by an external validation procedure with an independent sample set. The obtained results could be considered as quite good with coefficients of determination (R 2 ) varying from 0.94 to 0.97. The current methodology, using NIR spectroscopy and chemometrics, can be seen as a promising rapid tool to determine volatile compounds in Vinho Verde wines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Correlated Raman micro-spectroscopy and scanning electron microscopy analyses of flame retardants in environmental samples: a micro-analytical tool for probing chemical composition, origin and spatial distribution.

Science.gov (United States)

Ghosal, Sutapa; Wagner, Jeff

2013-07-07

We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.

Using polarized Raman spectroscopy and the pseudospectral method to characterize molecular structure and function

Science.gov (United States)

Weisman, Andrew L.

Electronic structure calculation is an essential approach for determining the structure and function of molecules and is therefore of critical interest to physics, chemistry, and materials science. Of the various algorithms for calculating electronic structure, the pseudospectral method is among the fastest. However, the trade-off for its speed is more up-front programming and testing, and as a result, applications using the pseudospectral method currently lag behind those using other methods. In Part I of this dissertation, we first advance the pseudospectral method by optimizing it for an important application, polarized Raman spectroscopy, which is a well-established tool used to characterize molecular properties. This is an application of particular importance because often the easiest and most economical way to obtain the polarized Raman spectrum of a material is to simulate it; thus, utilization of the pseudospectral method for this purpose will accelerate progress in the determination of molecular properties. We demonstrate that our implementation of Raman spectroscopy using the pseudospectral method results in spectra that are just as accurate as those calculated using the traditional analytic method, and in the process, we derive the most comprehensive formulation to date of polarized Raman intensity formulas, applicable to both crystalline and isotropic systems. Next, we apply our implementation to determine the orientations of crystalline oligothiophenes -- a class of materials important in the field of organic electronics -- achieving excellent agreement with experiment and demonstrating the general utility of polarized Raman spectroscopy for the determination of crystal orientation. In addition, we derive from first-principles a method for using polarized Raman spectra to establish unambiguously whether a uniform region of a material is crystalline or isotropic. Finally, we introduce free, open-source software that allows a user to determine any of a

Characterization of ZnO nanostructures: A challenge to positron annihilation spectroscopy and other methods

Energy Technology Data Exchange (ETDEWEB)

Brauer, Gerhard; Anwand, Wolfgang; Grambole, Dieter; Skorupa, Wolfgang [Institut fuer Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden-Rossendorf, Dresden (Germany); Egger, Werner; Sperr, Peter [Institut fuer Angewandte Physik und Messtechnik LRT2, Fakultaet fuer Luft- und Raumfahrttechnik, Werner-Heisenberg-Weg 39, Universitaet der Bundeswehr, Neubiberg (Germany); Beinik, Igor; Wang, Lin; Teichert, Christian [Institut fuer Physik, Montanuniversitaet Leoben (Austria); Kuriplach, Jan; Lang, Jan [Department of Low Temperature Physics, Charles University, Prague (Czech Republic); Zviagin, Sergei; Cizmar, Erik [Institut Hochfeld-Magnetlabor, Forschungszentrum Dresden-Rossendorf, Dresden (Germany); Ling, Chi Chung; Hsu, Yuk Fan; Xi, Yan Yan; Chen, Xinyi; Djurisic, Aleksandra B. [Department of Physics, University of Hong Kong, Hong Kong (China)

2009-11-15

ZnO nanostructures are of special interest for device applications. However, their structural characterization remains an ongoing challenge. This paper reviews recent efforts and latest achievements in this direction. Results comprise PAS in the form of Slow Positron Implantation Spectroscopy (SPIS) and Pulsed Low Energy Positron Lifetime Spectroscopy (PLEPS), Nuclear Reaction Analysis (NRA), Atomic Force Microscopy (AFM), conductive AFM (C-AFM), Nuclear Magnetic Resonance (NMR), Electron Spin Resonance (ESR), Photoluminescence (PL) spectroscopy, and latest theoretical investigations of structure-related and positron properties of selected defects. The fundamental importance of a relationship between fabrication conditions, native defect formation, and resulting optical and electronic properties is demonstrated by getting either inferior (nanorods) or significantly improved (tetrapods) optical properties compared to single crystal samples, depending on the nanostructure fabrication method. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Characterization of the ground state dynamics of proteorhodopsin by NMR and optical spectroscopies

International Nuclear Information System (INIS)

Stehle, Jochen; Scholz, Frank; Löhr, Frank; Reckel, Sina; Roos, Christian; Blum, Michaela; Braun, Markus; Glaubitz, Clemens; Dötsch, Volker; Wachtveitl, Josef; Schwalbe, Harald

2012-01-01

We characterized the dynamics of proteorhodopsin (PR), solubilized in diC7PC, a detergent micelle, by liquid-state NMR spectroscopy at T = 323 K. Insights into the dynamics of PR at different time scales could be obtained and dynamic hot spots could be identified at distinct, functionally relevant regions of the protein, including the BC loop, the EF loop, the N-terminal part of helix F and the C-terminal part of helix G. We further characterize the dependence of the photocycle on different detergents (n-Dodecyl β-D-maltoside DDM; 1,2-diheptanoyl-sn-glycero-3-phosphocholine diC7PC) by ultrafast time-resolved UV/VIS spectroscopy. While the photocycle intermediates of PR in diC7PC and DDM exhibit highly similar spectral characteristics, significant changes in the population of these intermediates are observed. In-situ NMR experiments have been applied to characterize structural changes during the photocycle. Light-induced chemical shift changes detected during the photocycle in diC7PC are very small, in line with the changes in the population of intermediates in the photocycle of proteorhodopsin in diC7PC, where the late O-intermediate populated in DDM is missing and the population is shifted towards an equilibrium of intermediates states (M, N, O) without accumulation of a single populated intermediate.

Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues

Science.gov (United States)

Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

2017-12-01

Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics.

Synthesizing and Characterizing Graphene via Raman Spectroscopy: An Upper-Level Undergraduate Experiment That Exposes Students to Raman Spectroscopy and a 2D Nanomaterial

Science.gov (United States)

Parobek, David; Shenoy, Ganesh; Zhou, Feng; Peng, Zhenbo; Ward, Michelle; Liu, Haitao

2016-01-01

In this upper-level undergraduate experiment, students utilize micro-Raman spectroscopy to characterize graphene prepared by mechanical exfoliation and chemical vapor deposition (CVD). The mechanically exfoliated samples are prepared by the students while CVD graphene can be purchased or obtained through outside sources. Owing to the intense Raman…

Metabolomics As a Tool for the Characterization of Drug-Resistant Epilepsy

Directory of Open Access Journals (Sweden)

Federica Murgia

2017-09-01

Full Text Available PurposeDrug resistance is a critical issue in the treatment of epilepsy, contributing to clinical emergencies and increasing both serious social and economic burdens on the health system. The wide variety of potential drug combinations followed by often failed consecutive attempts to match drugs to an individual patient may mean that this treatment stage may last for years with suboptimal benefit to the patient. Given these challenges, it is valuable to explore the availability of new methodologies able to shorten the period of determining a rationale pharmacologic treatment. Metabolomics could provide such a tool to investigate possible markers of drug resistance in subjects with epilepsy.MethodsBlood samples were collected from (1 controls (C (n = 35, (2 patients with epilepsy “responder” (R (n = 18, and (3 patients with epilepsy “non-responder” (NR (n = 17 to the drug therapy. The samples were analyzed using nuclear magnetic resonance spectroscopy, followed by multivariate statistical analysis.Key findingsA different metabolic profile based on metabolomics analysis of the serum was observed between C and patients with epilepsy and also between R and NR patients. It was possible to identify the discriminant metabolites for the three classes under investigation. Serum from patients with epilepsy were characterized by increased levels of 3-OH-butyrate, 2-OH-valerate, 2-OH-butyrate, acetoacetate, acetone, acetate, choline, alanine, glutamate, scyllo-inositol (C < R < NR, and decreased concentration of glucose, lactate, and citrate compared to C (C > R > NR.SignificanceIn conclusion, metabolomics may represent an important tool for discovery of differences between subjects affected by epilepsy responding or resistant to therapies and for the study of its pathophysiology, optimizing the therapeutic resources and the quality of life of patients.

Raman Spectroscopy of Solid Oxide Fuel Cells: Technique Overview and Application to Carbon Deposition Analysis

KAUST Repository

Maher, R. C.; Duboviks, V.; Offer, G. J.; Kishimoto, M.; Brandon, N. P.; Cohen, L. F.

2013-01-01

Raman spectroscopy is a powerful characterization tool for improving the understanding of solid oxide fuel cells (SOFCs), capable of providing direct, molecularly specific information regarding the physical and chemical processes occurring within functional SOFCs in real time. In this paper we give a summary of the technique itself and highlight ex situ and in situ studies that are particularly relevant for SOFCs. This is followed by a case study of carbon formation on SOFC Ni-based anodes exposed to carbon monoxide (CO) using both ex situ and in situ Raman spectroscopy combined with computational simulations. In situ measurements clearly show that carbon formation is significantly reduced for polarized SOFCs compared to those held at open circuit potential (OCP). Ex situ Raman mapping of the surfaces showed clear variations in the rate of carbon formation across the surface of polarized anodes. Computational simulations describing the geometry of the cell showed that this is due to variations in gas access. These results demonstrate the ability of Raman spectroscopy in combination with traditional characterization tools, to provide detailed understanding of critical processes occurring within functional SOFCs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Raman Spectroscopy of Solid Oxide Fuel Cells: Technique Overview and Application to Carbon Deposition Analysis

KAUST Repository

Maher, R. C.

2013-07-30

Raman spectroscopy is a powerful characterization tool for improving the understanding of solid oxide fuel cells (SOFCs), capable of providing direct, molecularly specific information regarding the physical and chemical processes occurring within functional SOFCs in real time. In this paper we give a summary of the technique itself and highlight ex situ and in situ studies that are particularly relevant for SOFCs. This is followed by a case study of carbon formation on SOFC Ni-based anodes exposed to carbon monoxide (CO) using both ex situ and in situ Raman spectroscopy combined with computational simulations. In situ measurements clearly show that carbon formation is significantly reduced for polarized SOFCs compared to those held at open circuit potential (OCP). Ex situ Raman mapping of the surfaces showed clear variations in the rate of carbon formation across the surface of polarized anodes. Computational simulations describing the geometry of the cell showed that this is due to variations in gas access. These results demonstrate the ability of Raman spectroscopy in combination with traditional characterization tools, to provide detailed understanding of critical processes occurring within functional SOFCs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of superconducting thin films by infrared reflection

International Nuclear Information System (INIS)

Gervais, F.

1988-01-01

Infrared reflectivity spectroscopy is shown to be a powerful tool to characterize the new high-Tc oxide superconductors since it gives information about the superconducting gap, phonons, plasmon and possibly low-energy electronic excitations such as excitons, information relevant to understand the mechanism of superconductivity [fr

Fourier transform-infrared spectroscopy as a diagnostic tool for mosquito coil smoke inhalation toxicity in Swiss Albino mice

Science.gov (United States)

Anusha, Chidambaram; Sankar, Renu; Varunkumar, Krishnamoorthy; Sivasindhuja, Gnanasambantham; Ravikumar, Vilwanathan

2017-12-01

The goal of this study is to establish Fourier transform-infrared (FTIR) spectroscopy as a diagnostic tool for allethrin-based mosquito coil smoke inhalation induced toxicity in mice. Primarily, we confirmed mosquito coil smoke inhalation toxicity in mice via reduced the body, organ weight and major vital organ tissue morphological structure changes. Furthermore, FTIR spectra was collected from control and mosquito coil smoke inhalation (8 h per day for 30 days) mice various tissues like liver, kidney, lung, heart and brain, to investigate the functional groups and their corresponding biochemical content variations. The FTIR spectra result shown major bio macromolecules such as protein and lipid functional peaks were shifted (decreased) in the mosquito coil smoke inhalation group as compared to control. The drastic peak shift was noticed in the liver, kidney followed by lung and brain. It is therefore concluded that the FTIR spectroscopy can be a successful detection tool in mosquito coil smoke inhalation toxicity.

Optical tool for salinity detection by remote sensing spectroscopy: application on Oran watershed, Algeria

Science.gov (United States)

Abdellatif, Dehni; Mourad, Lounis

2017-07-01

Soil salinity is a complex problem that affects groundwater aquifers and agricultural lands in the semiarid regions. Remote sensing and spectroscopy database systems provide accuracy for salinity autodetection and dynamical delineation. Salinity detection techniques using polychromatic wavebands by field geocomputation and experimental data are time consuming and expensive. This paper presents an automated spectral detection and identification of salt minerals using a monochromatic waveband concept from multispectral bands-Landsat 8 Operational Land Imager (OLI) and Thermal InfraRed Sensor (TIRS) and spectroscopy United States Geological Survey database. For detecting mineral salts related to electrolytes, such as electronical and vibrational transitions, an integrated approach of salinity detection related to the optical monochromatic concept has been addressed. The purpose of this paper is to discriminate waveband intrinsic spectral similarity using the Beer-Lambert and Van 't Hoff laws for spectral curve extraction such as transmittance, reflectance, absorbance, land surface temperature, molar concentration, and osmotic pressure. These parameters are primordial for hydrodynamic salinity modeling and continuity identification using chemical and physical approaches. The established regression fitted models have been addressed for salt spectroscopy validation for suitable calibration and validation. Furthermore, our analytical tool is conducted for better decision interface using spectral salinity detection and identification in the Oran watershed, Algeria.

Conversion electron Moessbauer spectroscopy of plasma immersion ion implanted H13 tool steel

International Nuclear Information System (INIS)

Terwagne, G.; Hutchings, R.

1994-01-01

Conversion electron Moessbauer spectroscopy (CEMS) has been used to investigate nitride formation in AISI-H13 tool steel after treatment by plasma immersion ion implantation (PI 3 ) at 350 C. With only slight variation in the plasma conditions, it is possible to influence the kinetics of nitride precipitation so as to obtain nitrogen concentrations that range from those associated with ε-Fe 2 N through ε-Fe 3 N to γ'-Fe 4 N. The CEMS results enable a more definite identification of the nitrides than that obtained by glancing-angle X-ray diffraction and nuclear reaction analysis alone. (orig.)

Acoustic force spectroscopy

NARCIS (Netherlands)

Sitters, G.; Kamsma, D.; Thalhammer, G.; Ritsch-Marte, M.; Peterman, E.J.G.; Wuite, G.J.L.

2015-01-01

Force spectroscopy has become an indispensable tool to unravel the structural and mechanochemical properties of biomolecules. Here we extend the force spectroscopy toolbox with an acoustic manipulation device that can exert forces from subpiconewtons to hundreds of piconewtons on thousands of

Near infrared spectroscopy in the development of solid dosage forms.

Science.gov (United States)

Räsänen, Eetu; Sandler, Niklas

2007-02-01

The use of near infrared (NIR) spectroscopy has rapidly grown partly due to demands of process analytical applications in the pharmaceutical industry. Furthermore, newest regulatory guidelines have advanced the increase of the use of NIR technologies. The non-destructive and non-invasive nature of measurements makes NIR a powerful tool in characterization of pharmaceutical solids. These benefits among others often make NIR advantageous over traditional analytical methods. However, in addition to NIR, a wide variety of other tools are naturally also available for analysis in pharmaceutical development and manufacturing, and those can often be more suitable for a given application. The versatility and rapidness of NIR will ensure its contribution to increased process understanding, better process control and improved quality of drug products. This review concentrates on the use of NIR spectroscopy from a process research perspective and highlights recent applications in the field.

Characterization of vacancy type defects in Electronic Materials by Positron Lifetime and Age-Momentum Correlation Spectroscopy

Science.gov (United States)

Suzuki, Ryoichi; Ohdaira, Toshiyuki

2002-03-01

Positron annihilation spectroscopy is known to be sensitive to vacancy type defects. At the National Institute of Advanced Industrial Science and Technology (AIST) Japan, the authors have developed a measurement system which enables us to perform depth-selective positron annihilation lifetime spectroscopy (PALS) and positron age-momentum correlation (AMOC) spectroscopy with an intense slow positron beam. PALS gives us information on the size of vacancies whereas AMOC gives us information on not only vacancy sizes but also impurities or chemical environments. Using this system, we have carried out defect characterization experiments on various electronic materials, e.g. ion implanted Si, SiO2/Si, MOS, CVD or SOD (spin-on-dielectric) grown low dielectric insulator films, etc.

Characterization of bundled and individual triple-walled carbon nanotubes by resonant Raman spectroscopy.

Science.gov (United States)

Hirschmann, Thomas Ch; Araujo, Paulo T; Muramatsu, Hiroyuki; Zhang, Xu; Nielsch, Kornelius; Kim, Yoong Ahm; Dresselhaus, Mildred S

2013-03-26

The optical characterization of bundled and individual triple-walled carbon nanotubes was studied for the first time in detail by using resonant Raman spectroscopy. In our approach, the outer tube of a triple-walled carbon nanotube system protects the two inner tubes (or equivalently the inner double-walled carbon nanotube) from external environment interactions making them a partially isolated system. Following the spectral changes and line-widths of the radial breathing modes and G-band by performing laser energy dependent Raman spectroscopy, it is possible to extract important information as regards to the electronic and vibrational properties, tube diameters, wall-to-wall distances, radial breathing mode, and G-band resonance evolutions as well as high-curvature intertube interactions in isolated double- and triple-walled carbon nanotube systems.

Pinpointing water entries using pulsed neutron and Production logging tools

International Nuclear Information System (INIS)

Mukerji, P.; Oluwa, J.

2003-01-01

A successful work over requires a comprehensive understanding of fluid entries into the wellbore and fluid contact movement in the reservoir. Such information can be obtained by a combination of production logs and saturation-monitoring measurements. The ability to combine pulsed neutron and production logging tools provides the operator with better diagnostics for identifying candidates for remedial actions and greatly increases the possibility of a successful well intervention. Advances in pulsed neutron spectroscopy tools have improved the accuracy and precision of measured carbon/oxygen ratios. Some of the improvements in accuracy and precision have resulted from better tool characterization in a wider variety of logging environments in the calibration facility and new spectral standards. Coincident with the advances in pulsed neutron spectroscopy has been the development of production logging measurements run on a platform common. We will show how the application of pulsed neutron and production logs can optimize subsequent well intervention to reduce water production and/or increase oil production

High resolution spectroscopy in the microwave and far infrared

Science.gov (United States)

Pickett, Herbert M.

1990-01-01

High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

Laminated helmet materials characterization by terahertz kinetics spectroscopy

Science.gov (United States)

Rahman, Anis; Rahman, Aunik K.

2015-05-01

High speed acquisition of reflected terahertz energy constitutes a kinetics spectrum that is an effective tool for layered materials' deformation characterization under ballistic impact. Here we describe utilizing the kinetics spectrum for quantifying a deformation event due to impact in material used for Soldier's helmet. The same technique may be utilized for real-time assessment of trauma by measuring the helmet wore by athletes. The deformation of a laminated material (e.g., a helmet) is dependent on the nature of impact and projectile; thus can uniquely characterize the impact condition leading to a diagnostic procedure based on the energy received by an athlete during an impact. We outline the calibration process for a given material under ballistic impact and then utilize the calibration for extracting physical parameters from the measured kinetics spectrum. Measured kinetics spectra are used to outline the method and rationale for extending the concept to a diagnosis tool. In particular, captured kinetics spectra from multilayered plates subjected to ballistic hit under experimental conditions by high speed digital acquisition system. An algorithm was devised to extract deformation and deformation velocity from which the energy received on the skull was estimated via laws of nonrelativistic motion. This energy is assumed to be related to actual injury conditions, thus forming a basis for determining whether the hit would cause concussion, trauma, or stigma. Such quantification may be used for diagnosing a Soldier's trauma condition in the field or that of an athlete's.

Surface characterization of selected polymer thin films by total-reflection x-ray fluorescence spectroscopy and x-ray reflectivity

International Nuclear Information System (INIS)

Innis, Vallerie Ann A.

2006-01-01

Development of available x-ray characterizations tools for grazing incidence techniques was done to be able to probe nano-size thin films. Alignment of a Philips x-ray powder diffractometer was improved to let it perform as an x-ray reflectometer. X-ray reflectometry was coupled with total-reflection x-ray fluorescence spectroscopy. Evaluation of the performance of this grazing incidence techniques was done by preparing polymer thin films of carboxymethylcellulose, carrageenan and polyvinylpyrrolidone (PVP). The thickness of the films were varied by varying the process parameters such as concentration, spin speed and spin time. Angle-dispersive total-reflection x-ray fluorescence spectroscopy profiles of three films showed film formation only in carrageenan and PVP. For both carrageenan and PVP, an increase in concentration yielded a corresponding increase in intensity of the fluorescent or scattered peaks. XRR profiles of carrageenan thin films yielded a mean value for the critical angle close to quartz substrate. Thickness measurements of the prepared carrageenan thin films showed that concentration was the main determinant for final film thickness over the other process parameters. Sulfur fluorescent intensity derived from the TXRF measurement showed a linear relationship with the measured thickness by XRR. For PVP, measured critical angle is lower than quartz. Poor adhesion of the polymer onto the substrate yielded a limited number of thickness measurements made from the XRR profiles. (Author)

Recent Advances in the Characterization of Gaseous and Liquid Fuels by Vibrational Spectroscopy

Directory of Open Access Journals (Sweden)

Johannes Kiefer

2015-04-01

Full Text Available Most commercial gaseous and liquid fuels are mixtures of multiple chemical compounds. In recent years, these mixtures became even more complicated when the suppliers started to admix biofuels into the petrochemical basic fuels. As the properties of such mixtures can vary with composition, there is a need for reliable analytical technologies in order to ensure stable operation of devices such as internal combustion engines and gas turbines. Vibrational spectroscopic methods have proved their suitability for fuel characterization. Moreover, they have the potential to overcome existing limitations of established technologies, because they are fast and accurate, and they do not require sampling; hence they can be deployed as inline sensors. This article reviews the recent advances of vibrational spectroscopy in terms of infrared absorption (IR and Raman spectroscopy in the context of fuel characterization. The focus of the paper lies on gaseous and liquid fuels, which are dominant in the transportation sector and in the distributed generation of power. On top of an introduction to the physical principles and review of the literature, the techniques are critically discussed and compared with each other.

Neuroimaging in Parkinsonism: a study with magnetic resonance and spectroscopy as tools in the differential diagnosis

Energy Technology Data Exchange (ETDEWEB)

Vasconcellos, Luiz Felipe Rocha [1Hospital dos Servidores do Estado, Rio de Janeiro RJ (Brazil)], e-mail: luizneurol@terra.com.br; Novis, Sergio A. Pereira; Rosso, Ana Lucia Z. [Hospital Universitario Clementino Fraga Filho (HUCFF), Rio de Janeiro, RJ (Brazil); Moreira, Denise Madeira [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Neurologia Deolindo Couto; Leite, Ana Claudia C.B. [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil)

2009-03-15

The differential diagnosis of Parkinsonism based on clinical features, sometimes may be difficult. Diagnostic tests in these cases might be useful, especially magnetic resonance imaging, a noninvasive exam, not as expensive as positron emission tomography, and provides a good basis for anatomical analysis. The magnetic resonance spectroscopy analyzes cerebral metabolism, yielding inconsistent results in parkinsonian disorders. We selected 40 individuals for magnetic resonance imaging and spectroscopy analysis, 12 with Parkinson's disease, 11 with progressive supranuclear palsy, 7 with multiple system atrophy (parkinsonian type), and 10 individuals without any psychiatric or neurological disorders (controls). Clinical scales included Hoenh and Yahr, unified Parkinson's disease rating scale and mini mental status examination. The results showed that patients with Parkinson's disease and controls presented the same aspects on neuroimaging, with few or absence of abnormalities, and supranuclear progressive palsy and multiple system atrophy showed abnormalities, some of which statistically significant. Thus, magnetic resonance imaging and spectroscopy could be useful as a tool in differential diagnosis of Parkinsonism. (author)

X-ray photoelectron spectroscopy characterization of the ω phase in water quenched Ti-5553 alloy

International Nuclear Information System (INIS)

Qin, Dongyang; Lu, Yafeng; Zhang, Kong; Liu, Qian; Zhou, Lian

2012-01-01

X-ray photoelectron spectroscopy was used to investigate the ω phase in water quenched Ti-5553 alloy with a nominal composition of Ti–5Al–5V–5Mo–3Cr (wt.%), and the ω and the β phase were distinguished by deconvoluting the XPS spectra of Al2p, V2p and Cr2p core level regions. In addition, it is found that the binding energy of core level electron of alloying elements shifts comparing with that of pure metals, and the fact was interpreted by charge redistribution model. X-ray photoelectron spectroscopy technique could be used to characterize the nano-scale ω phase in β alloys. - Highlights: ► We characterize the ω phase in Ti-5553 alloy by XPS. ► Binding energy of Al2p, V2p and Cr2p electron are different in the ω and β phase. ► Structural difference leads to the binding energy gap.

Raman spectroscopy for the microbiological characterization and identification of medically relevant bacteria

Science.gov (United States)

Hamasha, Khozima Mahmoud

The detection and identification of pathogenic bacteria has become more important than ever due to the increase of potential bioterrorism threats and the high mortality rate of bacterial infections worldwide. Raman spectroscopy has recently gained popularity as an attractive robust approach for the molecular characterization, rapid identification, and accurate classification of a wide range of bacteria. In this dissertation, Raman spectroscopy utilizing advanced statistical techniques was used to identify and discriminate between different pathogenic and non-pathogenic bacterial strains of E. coli and Staphylococcus aureus bacterial species by probing the molecular compositions of the cells. The five-carbon sugar xylitol, which cannot be metabolized by the oral and nasopharyngeal bacteria, had been recognized by clinicians as a preventive agents for dental caries and many studies have demonstrated that xylitol causes a reduction in otitis media (chronic inner ear infections) and other nasopharyngeal infections. Raman spectroscopy was used to characterize the uptake and metabolic activity of xylitol in pathogenic (viridans group Streptococcus) and nonpathogenic (E. coli) bacteria by taking their Raman spectra before xylitol exposure and after growing with xylitol and quantifying the significant differences in the molecular vibrational modes due to this exposure. The results of this study showed significant stable spectral changes in the S. viridians bacteria induced by xylitol and those changes were not the same as in some E. coli strains. Finally, Raman spectroscopy experiments were conducted to provide important information about the function of a certain protein (wag31) of Mycobacterium tuberculosis using a relative non-pathogenic bacterium called Mycobacterium smegmatis. Raman spectra of conditional mutants of bacteria expressing three different phosphorylation forms of wag31 were collected and analyzed. The results show that that the phosphorylation of wag31

Applicability of UV laser-induced solid-state fluorescence spectroscopy for characterization of solid dosage forms.

Science.gov (United States)

Woltmann, Eva; Meyer, Hans; Weigel, Diana; Pritzke, Heinz; Posch, Tjorben N; Kler, Pablo A; Schürmann, Klaus; Roscher, Jörg; Huhn, Carolin

2014-10-01

High production output of solid pharmaceutical formulations requires fast methods to ensure their quality. Likewise, fast analytical procedures are required in forensic sciences, for example at customs, to substantiate an initial suspicion. We here present the design and the optimization of an instrumental setup for rapid and non-invasive characterization of tablets by laser-induced fluorescence spectroscopy (with a UV-laser (λ ex = 266 nm) as excitation source) in reflection geometry. The setup was first validated with regard to repeatability, bleaching phenomena, and sensitivity. The effect on the spectra by the physical and chemical properties of the samples, e.g. their hardness, homogeneity, chemical composition, and granule grain size of the uncompressed material, using a series of tablets, manufactured in accordance with design of experiments, was investigated. Investigation of tablets with regard to homogeneity, especially, is extremely important in pharmaceutical production processes. We demonstrate that multiplicative scatter correction is an appropriate tool for data preprocessing of fluorescence spectra. Tablets with different physical and chemical characteristics can be discriminated well from their fluorescence spectra by subjecting the results to principal component analysis.

Mechanical Resonators for Material Characterization: Sensor Development and Applications

DEFF Research Database (Denmark)

Casci Ceccacci, Andrea; Bosco, Filippo Giacomo

The goals of this PhD project were to provide new approaches and developing new systems for material characterization, based on micro and nanomechanical sensors. Common issues that have shown to hinder large-scale integration of sensing techniques based on a micromechanical sensor are the readout......-co-Glycolic Acid (PLGA), which is of high relevance in the biomedical research field. A second version of the system is currently under development, and it aims to increase the throughput of the system allowing to read out multiple microbridge arrays. For material characterization, spectroscopy analysis is often...... considered a benchmark technology. Conventional infrared spectroscopy approaches commonly require milligram amount of sample. Considering the frame of reference given by the overall aim of the project, mechanical sensors can be exploited to provide a unique tool for performing spectroscopy on a limited...

Applications of UV/Vis Spectroscopy in Characterization and Catalytic Activity of Noble Metal Nanoparticles Fabricated in Responsive Polymer Microgels: A Review.

Science.gov (United States)

Begum, Robina; Farooqi, Zahoor H; Naseem, Khalida; Ali, Faisal; Batool, Madeeha; Xiao, Jianliang; Irfan, Ahmad

2018-11-02

Noble metal nanoparticles loaded smart polymer microgels have gained much attention due to fascinating combination of their properties in a single system. These hybrid systems have been extensively used in biomedicines, photonics, and catalysis. Hybrid microgels are characterized by using various techniques but UV/Vis spectroscopy is an easily available technique for characterization of noble metal nanoparticles loaded microgels. This technique is widely used for determination of size and shape of metal nanoparticles. The tuning of optical properties of noble metal nanoparticles under various stimuli can be studied using UV/Vis spectroscopic method. Time course UV/Vis spectroscopy can also be used to monitor the kinetics of swelling and deswelling of microgels and hybrid microgels. Growth of metal nanoparticles in polymeric network or growth of polymeric network around metal nanoparticle core can be studied by using UV/Vis spectroscopy. This technique can also be used for investigation of various applications of hybrid materials in catalysis, photonics, and sensing. This tutorial review describes the uses of UV/Vis spectroscopy in characterization and catalytic applications of responsive hybrid microgels with respect to recent research progress in this area.

Characterization of the electronic structure of C50Cl10 by means of soft x-ray spectroscopies

International Nuclear Information System (INIS)

Brena, Barbara; Luo Yi

2005-01-01

The electronic structure of the last synthesized fullerene molecule, the C 50 Cl 10 , has been characterized by theoretical simulation of x-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and near-edge x-ray-absorption fine structure. All the calculations were performed at the gradient-corrected and hybrid density-functional theory levels. The combination of these techniques provides detailed information about the valence band and the unoccupied molecular orbitals, as well as about the carbon core orbitals

[Near-infrared spectroscopy as an auxiliary tool in the study of child development].

Science.gov (United States)

Oliveira, Suelen Rosa de; Machado, Ana Carolina Cabral de Paula; Miranda, Débora Marques de; Campos, Flávio Dos Santos; Ribeiro, Cristina Oliveira; Magalhães, Lívia de Castro; Bouzada, Maria Cândida Ferrarez

2015-01-01

To investigate the applicability of Near-Infrared Spectroscopy (NIRS) for cortical hemodynamic assessment tool as an aid in the study of child development. Search was conducted in the PubMed and Lilacs databases using the following keywords: "psychomotor performance/child development/growth and development/neurodevelopment/spectroscopy/near-infrared" and their equivalents in Portuguese and Spanish. The review was performed according to criteria established by Cochrane and search was limited to 2003 to 2013. English, Portuguese and Spanish were included in the search. Of the 484 articles, 19 were selected: 17 cross-sectional and two longitudinal studies, published in non-Brazilian journals. The analyzed articles were grouped in functional and non-functional studies of child development. Functional studies addressed the object processing, social skills development, language and cognitive development. Non-functional studies discussed the relationship between cerebral oxygen saturation and neurological outcomes, and the comparison between the cortical hemodynamic response of preterm and term newborns. NIRS has become an increasingly feasible alternative and a potentially useful technique for studying functional activity of the infant brain. Copyright © 2015 Associação de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

Photoelectron spectroscopy of molecular beams

International Nuclear Information System (INIS)

Berkowitz, J.

1974-01-01

The history of physical science is replete with examples of phenomena initially discovered and investigated by physicists, which have subsequently become tools of the chemist. It is demonstrated in this paper that the field of photoelectron spectroscopy may develop in a reverse fashion. After a brief introduction to the subject, the properties characterized as physical ones, are discussed. These are intensities and angular distributions, from which one can infer transition probabilities and phase shifts. Three separate experiments are described which involve accurate intensity measurements and it is shown how an interpretation of the results by appropriate theory has given new insight into the photoionization process. (B.R.H.)

Intra-annual wave resource characterization for energy exploitation: A new decision-aid tool

International Nuclear Information System (INIS)

Carballo, R.; Sánchez, M.; Ramos, V.; Fraguela, J.A.; Iglesias, G.

2015-01-01

Highlights: • A decision-aid tool is developed for computing the monthly performance of WECs. • It allows the generation of high-resolution monthly characterization matrices. • The decision-aid tool is implemented to the Death Coast (N Spain). • The monthly matrices can be obtained at any coastal location within the Death Coast. • The tool is applied to a coastal location of a proposed wave farm. - Abstract: The wave energy resource is usually characterized by a significant variability throughout the year. In estimating the power performance of a Wave Energy Converter (WEC) it is fundamental to take into account this variability; indeed, an estimate based on mean annual values may well result in a wrong decision making. In this work, a novel decision-aid tool, iWEDGE (intra-annual Wave Energy Diagram GEnerator) is developed and implemented to a coastal region of interest, the Death Coast (Spain), one of the regions in Europe with the largest wave resource. Following a comprehensive procedure, and based on deep water wave data and high-resolution numerical modelling, this tool provides the monthly high-resolution characterization matrices (or energy diagrams) for any location of interest. In other words, the information required for the accurate computation of the intra-annual performance of any WEC at any location within the region covered is made available. Finally, an application of iWEDGE to the site of a proposed wave farm is presented. The results obtained highlight the importance of the decision-aid tool herein provided for wave energy exploitation

Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues.

Science.gov (United States)

Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

2017-10-01

Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Conversion electron Mössbauer spectroscopy of plasma immersion ion implanted H13 tool steel

Science.gov (United States)

Terwagne, G.; Collins, G. A.; Hutchings, R.

1994-12-01

Conversion electron Mössbauer spectroscopy (CEMS) has been used to investigate nitride formation in AISI-H13 tool steel after treatment by plasma immersion ion implantation (PI3) at 350 °C. With only slight variation in the plasma conditions, it is possible to influence the kinetics of nitride precipitation so as to obtain nitrogen concentrations that range from those associated with ɛ-Fe2N through ɛ-Fe3N to γ'-Fe4N. The CEMS results enable a more definite identification of the nitrides than that obtained by glancing-angle X-ray diffraction and nuclear reaction analysis alone.

Combined operando Raman/UV-Vis-NIR spectroscopy as a tool to study supported metal oxide catalysts at work

NARCIS (Netherlands)

Tinnemans, Stanislaus Josephus

2006-01-01

A novel set-up has been developed in which two complementary spectroscopic techniques, namely operando Raman and UV-Vis-NIR spectroscopy, are combined. With this set-up it is possible to characterize catalytic materials under reaction conditions (high temperature, normal pressure) and in this way on

High-resolution Raman Spectroscopy for the Nanostructural Characterization of Explosive Nanodiamond Precursors.

Science.gov (United States)

Deckert-Gaudig, Tanja; Pichot, Vincent; Spitzer, Denis; Deckert, Volker

2017-01-18

The specific attributes of nanodiamonds have attracted increasing interest for electronics or biomedical applications. An efficient synthetic route towards nanodiamonds is via detonation of hexolite (i.e. a mixture of TNT [2,4,6-trinitrotoluene] and RDX [1,3,5-trinitro-1,3,5-triazine]). In particular, detonation of hexolite crystallized by spray flash evaporation (SFE) yields extremely small diamonds (<4 nm). To unravel the detonation mechanism, a structural characterization of the explosives is required but is challenging due to their thermal instability. We demonstrate a combination of conventional Raman spectroscopy and tip-enhanced Raman spectroscopy (TERS) for resolving morphological and structural differences of differently prepared hexolite nanocomposites. The experiments allow for the first time a structural differentiation of individual TNT and RDX crystals and 15-20 nm sized core-shell structures, consequently providing a general approach to investigate the actual composition of mixtures on the nanometer scale. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental Characterization and Modeling of PEM Fuel Cells

DEFF Research Database (Denmark)

Jespersen, Jesper Lebæk

fundamental knowledge of the transport and electrochemical processes of PEM fuel cells and to provide methods for obtaining high quality data for PEM fuel cell simulation model validation. In this thesis three different areas of experimental characterization techniques was investigated, they include: Stack...... for obtaining very detailed data of the manifold flow. Moreover, the tools complement each other well, as high quality validation data can be obtained from PIV measurements to verify CFD models. AC Impedance Spectroscopy was used to thoroughly characterize a HTPEM single cell. The measurement method...... was furthermore transferred onto a Labview platform, which signiffcantly improves the exibility and lowers the cost of using this method. This technique is expected to bea very important future tool, used both for material characterization, celldiagnostic, system optimization and as a control input parameter...

Characterization of Paracoccidioides brasiliensis by FT-IR spectroscopy and nanotechnology

Science.gov (United States)

Ferreira, Isabelle; Ferreira-Strixino, Juliana; Castilho, Maiara L.; Campos, Claudia B. L.; Tellez, Claudio; Raniero, Leandro

2016-01-01

Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, is a dimorphic fungus existing as mycelia in the environment (or at 25 °C in vitro) and as yeast cells in the human host (or at 37 °C in vitro). Because mycological examination of lesions in patients frequently is unable to show the presence of the fungus and serological tests can misdiagnose the disease with other mycosis, the development of new approach's for molecular identification of P. brasiliensis spurges is needed. This study describes the use of a gold nanoprobe of a known gene sequence of P. brasiliensis as a molecular tool to identify P. brasiliensis by regular polymerase chain reaction (PCR) associated with a colorimetric methods. This approach is suitable for testing in remote areas because it does not require any further step than gene amplification, being safer and cheaper than electrophoresis methods. The proposed test showed a color change of the PCR reaction mixture from red to blue in negative samples, whereas the solution remains red in positive samples. We also performed a Fourier Transform Infrared (FT-IR) Spectroscopy analysis to characterize and compare the chemical composition between yeast and mycelia forms, which revealed biochemical differences between these two forms. The analysis of the spectra showed that differences were distributed in chemical bonds of proteins, lipids and carbohydrates. The most prominent difference between both forms was vibration modes related to 1,3-β-glucan usually found in mycelia and 1,3-α-glucan found in yeasts and also chitin forms. In this work, we introduce FT-IR as a new method suitable to reveal overall differences that biochemically distinguish each form of P. brasiliensis that could be additionally used to discriminate biochemical differences among a single form under distinct environmental conditions.

Characterization of dissolved organic matter in Dongjianghu Lake by UV-visible absorption spectroscopy with multivariate analysis.

Science.gov (United States)

Zhu, Yanzhong; Song, Yonghui; Yu, Huibin; Liu, Ruixia; Liu, Lusan; Lv, Chunjian

2017-08-08

UV-visible absorption spectroscopy coupled with principal component analysis (PCA) and hierarchical cluster analysis (HCA) was applied to characterize spectroscopic components, detect latent factors, and investigate spatial variations of dissolved organic matter (DOM) in a large-scale lake. Twelve surface water samples were collected from Dongjianghu Lake in China. DOM contained lignin and quinine moieties, carboxylic acid, microbial products, and aromatic and alkyl groups, which in the northern part of the lake was largely different from the southern part. Fifteen spectroscopic indices were deduced from the absorption spectra to indicate molecular weight or humification degree of DOM. The northern part of the lake presented the smaller molecular weight or the lower humification degree of DOM than the southern part. E 2/4 , E 3/4 , E 2/3 , and S 2 were latent factors of characterizing the molecular weight of DOM, while E 2/5 , E 3/5 , E 2/6 , E 4/5 , E 3/6 , and A 2/1 were latent factors of evaluating the humification degree of DOM. The UV-visible absorption spectroscopy combined with PCA and HCA may not only characterize DOM fractions of lakes, but may be transferred to other types of waterscape.

Time-Resolved Fluorescence Spectroscopy and Fluorescence Lifetime Imaging Microscopy for Characterization of Dendritic Polymer Nanoparticles and Applications in Nanomedicine

Directory of Open Access Journals (Sweden)

Alexander Boreham

2016-12-01

Full Text Available The emerging field of nanomedicine provides new approaches for the diagnosis and treatment of diseases, for symptom relief and for monitoring of disease progression. One route of realizing this approach is through carefully constructed nanoparticles. Due to the small size inherent to the nanoparticles a proper characterization is not trivial. This review highlights the application of time-resolved fluorescence spectroscopy and fluorescence lifetime imaging microscopy (FLIM for the analysis of nanoparticles, covering aspects ranging from molecular properties to particle detection in tissue samples. The latter technique is particularly important as FLIM allows for distinguishing of target molecules from the autofluorescent background and, due to the environmental sensitivity of the fluorescence lifetime, also offers insights into the local environment of the nanoparticle or its interactions with other biomolecules. Thus, these techniques offer highly suitable tools in the fields of particle development, such as organic chemistry, and in the fields of particle application, such as in experimental dermatology or pharmaceutical research.

Time-Resolved Fluorescence Spectroscopy and Fluorescence Lifetime Imaging Microscopy for Characterization of Dendritic Polymer Nanoparticles and Applications in Nanomedicine.

Science.gov (United States)

Boreham, Alexander; Brodwolf, Robert; Walker, Karolina; Haag, Rainer; Alexiev, Ulrike

2016-12-24

The emerging field of nanomedicine provides new approaches for the diagnosis and treatment of diseases, for symptom relief and for monitoring of disease progression. One route of realizing this approach is through carefully constructed nanoparticles. Due to the small size inherent to the nanoparticles a proper characterization is not trivial. This review highlights the application of time-resolved fluorescence spectroscopy and fluorescence lifetime imaging microscopy (FLIM) for the analysis of nanoparticles, covering aspects ranging from molecular properties to particle detection in tissue samples. The latter technique is particularly important as FLIM allows for distinguishing of target molecules from the autofluorescent background and, due to the environmental sensitivity of the fluorescence lifetime, also offers insights into the local environment of the nanoparticle or its interactions with other biomolecules. Thus, these techniques offer highly suitable tools in the fields of particle development, such as organic chemistry, and in the fields of particle application, such as in experimental dermatology or pharmaceutical research.

FTIR spectroscopy and X-ray powder diffraction characterization of microcrystalline cellulose obtained from alfa fibers

Directory of Open Access Journals (Sweden)

Trache D.

2013-07-01

Full Text Available Many cereal straws have been used as raw materials for the preparation of microcrystalline cellulose (MCC. These raw materials were gradually replaced with wood products; nevertheless about 10% of the world overall pulp production is obtained from non-wood raw material. The main interest in pulp made from straw is that it provides excellent fibres for different industries with special properties, and that it is the major available source of fibrous raw material in some geographical areas. The aim of the present work was to characterize microcrystalline cellulose prepared from alfa fibers using the hydrolysis process. The products obtained are characterized with FTIR spectroscopy and X-ray powder diffraction. As a result, FTIR spectroscopy is an appropriate technique for studying changes occurred by any chemical treatment. The spectrum of alfa grass stems shows the presence of lignin and hemicelluloses. However, the cellulose spectrum indicates that the extraction of lignin and hemicellulose was effective. The X-ray analysis indicates that the microcrystalline cellulose is more crystalline than the source material.

Spectral characterization of crude oil using fluorescence (synchronous and time-resolved) and NIR (Near Infrared Spectroscopy); Caracterizacao espectral do petroleo utilizando fluorescencia (sincronizada e resolvida no tempo) e NIR (Near Infrared Spectroscopy)

Energy Technology Data Exchange (ETDEWEB)

Falla Sotelo, F.; Araujo Pantoja, P.; Lopez-Gejo, J.; Le Roux, G.A.C.; Nascimento, C.A.O. [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Quimica. Lab. de Simulacao e Controle de Processos; Quina, F.H. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica. Centro de Capacitacao e Pesquisa em Meio Ambiente (CEPEMA)

2008-07-01

The objective of the present work is to evaluate the performance of two spectroscopic techniques employed in the crude oil characterization: NIR spectroscopy and fluorescence spectroscopy (Synchronous fluorescence - SF and Time Resolved Fluorescence - TRF) for the development of correlation models between spectral profiles of crude oil samples and both physical properties (viscosity and API density) and physico-chemical properties (SARA analysis: Saturated, Aromatic, Resins and Asphaltenes). The better results for viscosity and density were obtained using NIR whose prediction capacity was good (1.5 cP and 0.5 deg API, respectively). For SARA analysis, fluorescence spectroscopy revealed its potential in the model calibration showing good results (R2 coefficients greater than 0.85). TRF spectroscopy had better performance than SF spectroscopy. (author)

Fourier Transform Infrared Spectroscopy (FTIR) as a Tool for the Identification and Differentiation of Pathogenic Bacteria.

Science.gov (United States)

Zarnowiec, Paulina; Lechowicz, Łukasz; Czerwonka, Grzegorz; Kaca, Wiesław

2015-01-01

Methods of human bacterial pathogen identification need to be fast, reliable, inexpensive, and time efficient. These requirements may be met by vibrational spectroscopic techniques. The method that is most often used for bacterial detection and identification is Fourier transform infrared spectroscopy (FTIR). It enables biochemical scans of whole bacterial cells or parts thereof at infrared frequencies (4,000-600 cm(-1)). The recorded spectra must be subsequently transformed in order to minimize data variability and to amplify the chemically-based spectral differences in order to facilitate spectra interpretation and analysis. In the next step, the transformed spectra are analyzed by data reduction tools, regression techniques, and classification methods. Chemometric analysis of FTIR spectra is a basic technique for discriminating between bacteria at the genus, species, and clonal levels. Examples of bacterial pathogen identification and methods of differentiation up to the clonal level, based on infrared spectroscopy, are presented below.

Cavity-enhanced spectroscopies

CERN Document Server

van Zee, Roger

2003-01-01

""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

Characterizing Exoplanet Habitability with Emission Spectroscopy

Science.gov (United States)

Robinson, Tyler

2018-01-01

Results from NASA’s Kepler mission and other recent exoplanet surveys have demonstrated that potentially habitable exoplanets are relatively common, especially in the case of low-mass stellar hosts. The next key question that must be addressed for such planets is whether or not these worlds are actually habitable, implying they could sustain surface liquid water. Only through investigations of the potential habitability of exoplanets and through searches for biosignatures from these planets will we be able to understand if the emergence of life is a common phenomenon in our galaxy. Emission spectroscopy for transiting exoplanets (sometimes called secondary eclipse spectroscopy) is a powerful technique that future missions will use to study the atmospheres and surfaces of worlds orbiting in the habitable zones of nearby, low-mass stars. Emission observations that span the mid-infrared wavelength range for potentially habitable exoplanets provide opportunities to detect key habitability and life signatures, and also allow observers to probe atmospheric and surface temperatures. This presentation will outline the case for using emission spectroscopy to understand if an exoplanet can sustain surface liquid water, which is believed to be a critical precursor to the origin of life.

Characterization of Campylobacter jejuni applying flaA short variable region sequencing, multilocus sequencing and Fourier transform infrared spectroscopy

DEFF Research Database (Denmark)

Josefsen, Mathilde Hartmann; Bonnichsen, Lise; Larsson, Jonas

flaA short variable region sequencing and phenetic Fourier transform infrared (FTIR) spectroscopy was applied on a collection of 102 Campylobacter jejuni isolated from continuous sampling of organic, free range geese and chickens. FTIR has been shown to serve as a valuable tool in typing...

Electrochemical Characterization and Degradation Analysis of Large SOFC Stacks by Impedance Spectroscopy

DEFF Research Database (Denmark)

Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, R.

2013-01-01

As solid oxide fuel cell (SOFC) technology is moving closer to a commercial break through, lifetime limiting factors, and methods to measure the “state-of-health” of operating cells and stacks are becoming of increasing interest. This requires application of advanced methods for detailed...... electrochemical characterization during operation. An experimental stack with low ohmic resistance from Topsoe Fuel Cell A/S was characterized in detail using electrochemical impedance spectroscopy (EIS). An investigation of the optimal geometrical placement of the current feeds and voltage probes was carried out...... with hydrogen as fuel with 52% fuel utilization and constant current load (0.2 A cm–2) at 750 °C. Stack interconnects were coated with six different coatings to prevent chromium poisoning on the cathode side. Four repeating units (RUs) with different coatings were selected for detailed impedance analysis. EIS...

Synchrotron radiation-induced contamination on LiF window: Characterization by Raman spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Yadav, P. K., E-mail: praveenyadav@rrcat.gov.in [Material Research Laboratory, Indus Synchrotron Utilization Division (India); Swami, M. K. [Laser Biomedical Applications & Instrumentation Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

2016-05-23

Characterization of synchrotron induced contamination on optical elements and their cleaning are serious issues in beam lines. We used Raman spectroscopy for characterization of synchrotron induced contamination layer on LiF window (used in high resolution vacuum ultra violet beam line). Three peaks at 1035 cm{sup −1} (corresponding to C-C sp{sup 3} vibrations), 1563 cm{sup −1} and 1375 cm{sup −1} (corresponding to G and D bands of carbon) are observed. By data fitting I(D)/I(G) ratio (0.84) and FWHM(G)=124 cm{sup −1} was obtained. Comparison with available literature indicates that the carbon might be present in the form of rings of hydrogenated amorphous carbon a-C:H (GLHC) with atomic hydrogen concentration about 15% with both sp{sup 2} and sp{sup 3} hybridization.

Endogenous synchronous fluorescence spectroscopy (SFS) of basal cell carcinoma-initial study

Science.gov (United States)

Borisova, E.; Zhelyazkova, Al.; Keremedchiev, M.; Penkov, N.; Semyachkina-Glushkovskaya, O.; Avramov, L.

2016-01-01

The human skin is a complex, multilayered and inhomogeneous organ with spatially varying optical properties. Analysis of cutaneous fluorescence spectra could be a very complicated task; therefore researchers apply complex mathematical tools for data evaluation, or try to find some specific approaches, that would simplify the spectral analysis. Synchronous fluorescence spectroscopy (SFS) allows improving the spectral resolution, which could be useful for the biological tissue fluorescence characterization and could increase the tumour detection diagnostic accuracy.

Near-infrared spectroscopy (NIRS) as a new tool for neuroeconomic research

Science.gov (United States)

Kopton, Isabella M.; Kenning, Peter

2014-01-01

Over the last decade, the application of neuroscience to economic research has gained in importance and the number of neuroeconomic studies has grown extensively. The most common method for these investigations is fMRI. However, fMRI has limitations (particularly concerning situational factors) that should be countered with other methods. This review elaborates on the use of functional Near-Infrared Spectroscopy (fNIRS) as a new and promising tool for investigating economic decision making both in field experiments and outside the laboratory. We describe results of studies investigating the reliability of prototype NIRS studies, as well as detailing experiments using conventional and stationary fNIRS devices to analyze this potential. This review article shows that further research using mobile fNIRS for studies on economic decision making outside the laboratory could be a fruitful avenue helping to develop the potential of a new method for field experiments outside the laboratory. PMID:25147517

Toward the development of Raman spectroscopy as a nonperturbative online monitoring tool for gasoline adulteration.

Science.gov (United States)

Tan, Khay M; Barman, Ishan; Dingari, Narahara C; Singh, Gajendra P; Chia, Tet F; Tok, Wee L

2013-02-05

There is a critical need for a real-time, nonperturbative probe for monitoring the adulteration of automotive gasoline. Running on adulterated fuel leads to a substantive increase in air pollution, because of increased tailpipe emissions of harmful pollutants, as well as a reduction in engine performance. Consequently, both classification of the gasoline type and quantification of the adulteration content are of great significance for quality control. Gasoline adulteration detection is currently carried out in the laboratory with gas chromatography, which is time-consuming and costly. Here, we propose the application of Raman spectroscopic measurements for on-site rapid detection of gasoline adulteration. In this proof-of-principle report, we demonstrate the effectiveness of Raman spectra, in conjunction with multivariate analysis methods, in classifying the base oil types and simultaneously detecting the adulteration content in a wide range of commercial gasoline mixtures, both in their native states and spiked with different adulterants. In particular, we show that Raman spectra acquired with an inexpensive noncooled detector provides adequate specificity to clearly discriminate between the gasoline samples and simultaneously characterize the specific adulterant content with a limit of detection below 5%. Our promising results in this study illustrate, for the first time, the capability and the potential of Raman spectroscopy, together with multivariate analysis, as a low-cost, powerful tool for on-site rapid detection of gasoline adulteration and opens substantive avenues for applications in related fields of quality control in the oil industry.

Application of terahertz spectroscopy for characterization of biologically active organic molecules in natural environment

Science.gov (United States)

Karaliūnas, Mindaugas; Jakštas, Vytautas; Nasser, Kinan E.; Venckevičius, Rimvydas; Urbanowicz, Andrzej; Kašalynas, Irmantas; Valušis, Gintaras

2016-09-01

In this work, a comparative research of biologically active organic molecules in its natural environment using the terahertz (THz) time domain spectroscopy (TDS) and Fourier transform spectroscopy (FTS) systems is carried out. Absorption coefficient and refractive index of Nicotiana tabacum L. leaves containing nicotine, Cannabis sativa L. leaves containing tetrahydrocannabinol, and Humulu lupulus L. leaves containing α-acids, active organic molecules that obtain in natural environment, were measured in broad frequency range from 0.1 to 13 THz at room temperature. In the spectra of absorption coefficient the features were found to be unique for N. tabacum, C. sativa and H. lupulus. Moreover, those features can be exploited for identification of C. sativa sex and N. tabacum origin. The refractive index can be also used to characterize different species.

Dual THz comb spectroscopy

Science.gov (United States)

Yasui, Takeshi

2017-08-01

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

Estimation of carbonate concentration and characterization of marine sediments by Fourier transform infrared spectroscopy.

Digital Repository Service at National Institute of Oceanography (India)

Veerasingam, S.; Venkatachalapathy, R.

its saturation horizon is shallower than that calcite [1]. Elements such as Ca2+ and Mg2+, in addition to their substantial contribution to marine sediments, are used biologically in vital cellular processes and in the mineralization of skeletons... such as ocean acidification on ecosystems. Thus, a rapid, cheap and non-destructive tool is required to investigate the distribution of CaCO3 in sediments for the understanding of the fate of biologically produced carbonate. 3    FTIR spectroscopy is one...

Online UV-visible spectroscopy and multivariate curve resolution as powerful tool for model-free investigation of laccase-catalysed oxidation.

Science.gov (United States)

Kandelbauer, A; Kessler, W; Kessler, R W

2008-03-01

The laccase-catalysed transformation of indigo carmine (IC) with and without a redox active mediator was studied using online UV-visible spectroscopy. Deconvolution of the mixture spectra obtained during the reaction was performed on a model-free basis using multivariate curve resolution (MCR). Thereby, the time courses of educts, products, and reaction intermediates involved in the transformation were reconstructed without prior mechanistic assumptions. Furthermore, the spectral signature of a reactive intermediate which could not have been detected by a classical hard-modelling approach was extracted from the chemometric analysis. The findings suggest that the combined use of UV-visible spectroscopy and MCR may lead to unexpectedly deep mechanistic evidence otherwise buried in the experimental data. Thus, although rather an unspecific method, UV-visible spectroscopy can prove useful in the monitoring of chemical reactions when combined with MCR. This offers a wide range of chemists a cheap and readily available, highly sensitive tool for chemical reaction online monitoring.

Methodology for cork plank characterization (Quercus suber L.) by near-infrared spectroscopy and image analysis

Science.gov (United States)

Prades, Cristina; García-Olmo, Juan; Romero-Prieto, Tomás; García de Ceca, José L.; López-Luque, Rafael

2010-06-01

The procedures used today to characterize cork plank for the manufacture of cork bottle stoppers continue to be based on a traditional, manual method that is highly subjective. Furthermore, there is no specific legislation regarding cork classification. The objective of this viability study is to assess the potential of near-infrared spectroscopy (NIRS) technology for characterizing cork plank according to the following variables: aspect or visual quality, porosity, moisture and geographical origin. In order to calculate the porosity coefficient, an image analysis program was specifically developed in Visual Basic language for a desktop scanner. A set comprising 170 samples from two geographical areas of Andalusia (Spain) was classified into eight quality classes by visual inspection. Spectra were obtained in the transverse and tangential sections of the cork planks using an NIRSystems 6500 SY II reflectance spectrophotometer. The quantitative calibrations showed cross-validation coefficients of determination of 0.47 for visual quality, 0.69 for porosity and 0.66 for moisture. The results obtained using NIRS technology are promising considering the heterogeneity and variability of a natural product such as cork in spite of the fact that the standard error of cross validation (SECV) in the quantitative analysis is greater than the standard error of laboratory (SEL) for the three variables. The qualitative analysis regarding geographical origin achieved very satisfactory results. Applying these methods in industry will permit quality control procedures to be automated, as well as establishing correlations between the different classification systems currently used in the sector. These methods can be implemented in the cork chain of custody certification and will also provide a certainly more objective tool for assessing the economic value of the product.

Methodology for cork plank characterization (Quercus suber L.) by near-infrared spectroscopy and image analysis

International Nuclear Information System (INIS)

Prades, Cristina; López-Luque, Rafael; García-Olmo, Juan; Romero-Prieto, Tomás; García de Ceca, José L

2010-01-01

The procedures used today to characterize cork plank for the manufacture of cork bottle stoppers continue to be based on a traditional, manual method that is highly subjective. Furthermore, there is no specific legislation regarding cork classification. The objective of this viability study is to assess the potential of near-infrared spectroscopy (NIRS) technology for characterizing cork plank according to the following variables: aspect or visual quality, porosity, moisture and geographical origin. In order to calculate the porosity coefficient, an image analysis program was specifically developed in Visual Basic language for a desktop scanner. A set comprising 170 samples from two geographical areas of Andalusia (Spain) was classified into eight quality classes by visual inspection. Spectra were obtained in the transverse and tangential sections of the cork planks using an NIRSystems 6500 SY II reflectance spectrophotometer. The quantitative calibrations showed cross-validation coefficients of determination of 0.47 for visual quality, 0.69 for porosity and 0.66 for moisture. The results obtained using NIRS technology are promising considering the heterogeneity and variability of a natural product such as cork in spite of the fact that the standard error of cross validation (SECV) in the quantitative analysis is greater than the standard error of laboratory (SEL) for the three variables. The qualitative analysis regarding geographical origin achieved very satisfactory results. Applying these methods in industry will permit quality control procedures to be automated, as well as establishing correlations between the different classification systems currently used in the sector. These methods can be implemented in the cork chain of custody certification and will also provide a certainly more objective tool for assessing the economic value of the product

[Atomic force microscopy: a tool to analyze the viral cycle].

Science.gov (United States)

Bernaud, Julien; Castelnovo, Martin; Muriaux, Delphine; Faivre-Moskalenko, Cendrine

2015-05-01

Each step of the HIV-1 life cycle frequently involves a change in the morphology and/or mechanical properties of the viral particle or core. The atomic force microscope (AFM) constitutes a powerful tool for characterizing these physical changes at the scale of a single virus. Indeed, AFM enables the visualization of viral capsids in a controlled physiological environment and to probe their mechanical properties by nano-indentation. Finally, AFM force spectroscopy allows to characterize the affinities between viral envelope proteins and cell receptors at the single molecule level. © 2015 médecine/sciences – Inserm.

The use of dielectric spectroscopy for the characterization of polymer-induced flocculation of polystyrene particles

DEFF Research Database (Denmark)

Christensen, Peter Vittrup; Keiding, Kristian

2008-01-01

in dilute suspensions. Thus, techniques usable for flocculation characterization in high-solids suspensions are desirable. This study investigates the use of dielectric spectroscopy to monitor the flocculation of polystyrene particles with a cationic polymer. The frequency-dependent permittivity is modeled......The flocculation of colloidal suspensions is an important unit operation in many industries, as it greatly improves the performance of solid separation processes. The number of available techniques for evaluating flocculation processes on line is limited, and most of these are only functional...... as a decrease in the magnitude of the dielectric dispersion. The use of dielectric spectroscopy is found to be valuable for assessing flocculation processes in high-solids suspensions, as changes in parameters Such as floc size and charge can be detected....

Characterization system for Germanium detectors dedicated to gamma spectroscopy applied to nuclear waste

Energy Technology Data Exchange (ETDEWEB)

Roccaz, J.; Portella, C.; Saurel, N. [CEA, DAM, VALDUC, F-21120 Is-sur-Tille (France)

2009-07-01

CEA-Valduc produces some radioactive waste (mainly alpha emitters). Legislation requires producers to sort their waste by activity and type of isotopes, and to package them in order to forward them to the appropriate reprocessing or storage facility. Our lab LMDE (laboratory for measurements on nuclear wastes and valuation) is in charge of the characterization of the majority of waste produced by CEA-Valduc. Among non-destructive methods to characterize a radioactive object, gamma-spectroscopy is one of the most efficient. We present to this conference the method we use to characterize nuclear waste and the system we developed to characterize our germanium detectors. The goal of this system is to obtain reliable numerical models of our detectors and calculate their efficiency curves. Measurements are necessary to checks models and improve them. These measurements are made on a bench using pinpoint sources ({sup 133}Ba, {sup 152}Eu) from 60 keV to 1500 keV, with distances from 'on contact' to a few meters from the diode and variable angles between the source and the detector axis. We have demonstrated that we are able to obtain efficiency curves

Characterization of type I, II, III, IV, and V collagens by time-resolved laser-induced fluorescence spectroscopy

Science.gov (United States)

Marcu, Laura; Cohen, David; Maarek, Jean-Michel I.; Grundfest, Warren S.

2000-04-01

The relative proportions of genetically distinct collagen types in connective tissues vary with tissue type and change during disease progression, development, wound healing, aging. This study aims to 1) characterize the spectro- temporal fluorescence emission of fiber different types of collagen and 2) assess the ability of time-resolved laser- induced fluorescence spectroscopy to distinguish between collagen types. Fluorescence emission of commercially available purified samples was induced with nitrogen laser excitation pulses and detected with a MCP-PMT connected to a digital storage oscilloscope. The recorded time-resolved emission spectra displayed distinct fluorescence emission characteristics for each collagen type. The time domain information complemented the spectral domain intensity data for improved discrimination between different collagen types. Our results reveal that analysis of the fluorescence emission can be used to characterize different species of collagen. Also, the results suggest that time-resolved spectroscopy can be used for monitoring of connective tissue matrix composition changes due to various pathological and non-pathological conditions.

High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter; La spectroscopie de neutrons a haute resolution-un outil pour l'etude de la dynamique des polymeres et de la matiere molle

Energy Technology Data Exchange (ETDEWEB)

Monkenbusch, M.; Richter, D. [Institut fur Festkorperforschung (IFF), Forschungszentrum Julich, Julich (Germany)

2007-09-15

Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

Directory of Open Access Journals (Sweden)

Javis Anyangwe Nwaboh

2011-01-01

Full Text Available We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS, quantum cascade laser absorption spectroscopy (QCLAS, and cavity ring down spectroscopy (CRDS, all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.

Anharmonic Vibrational Spectroscopy on Metal Transition Complexes

Science.gov (United States)

Latouche, Camille; Bloino, Julien; Barone, Vincenzo

2014-06-01

Advances in hardware performance and the availability of efficient and reliable computational models have made possible the application of computational spectroscopy to ever larger molecular systems. The systematic interpretation of experimental data and the full characterization of complex molecules can then be facilitated. Focusing on vibrational spectroscopy, several approaches have been proposed to simulate spectra beyond the double harmonic approximation, so that more details become available. However, a routine use of such tools requires the preliminary definition of a valid protocol with the most appropriate combination of electronic structure and nuclear calculation models. Several benchmark of anharmonic calculations frequency have been realized on organic molecules. Nevertheless, benchmarks of organometallics or inorganic metal complexes at this level are strongly lacking despite the interest of these systems due to their strong emission and vibrational properties. Herein we report the benchmark study realized with anharmonic calculations on simple metal complexes, along with some pilot applications on systems of direct technological or biological interest.

Ultraviolet-visible and fluorescence spectroscopy can be used as a diagnostic tool for gamma irradiation detection in vivo.

Science.gov (United States)

K-Abdelhalim, Mohamed Anwar; Moussa, Sherif A-Abdelmottaleb

2016-09-01

The spectroscopic properties can indicate important features about the nature and severity of the disease. However, no earlier studies have been used the spectroscopic properties as a diagnostic tool for radiation detection. This study was aimed to use ultraviolet-visible and fluorescence spectroscopy as a diagnostic tool for gamma irradiation detection in rats in vivo. Adult male rats were exposed to 25, 50, 75 and 100 Gray as single dose, using Cobalt-60 (Co-60) source with a dose rate of 0.883 centi Gray/sec (cGy/s). Ultraviolet and fluorescence spectroscopy of rat's blood serum were measured. After gamma irradiation of rats in vivo, the blood serum absorbance peaks for 25, 50, 75 and 100 Gray (Gy) decreased and shifted towards the ultra violet wavelength. A maximal change in fluorescence intensity of blood serum at 350 nm was obtained when exciting light at 194 nm after irradiation. The fluorescence intensity also decreased with the dose. The highest radiation gamma dose might be accompanied with the highest oxidative stress. This study suggests that at the above mentioned gamma radiation doses, the blood is highly fragmented; with low aggregation at 25 Gy and with high aggregation at 50-100 Gy.

Structural Characterization of Laboratory Made Tholins by IRMPD Action Spectroscopy and Ultrahigh Resolution Mass Spectrometry

Science.gov (United States)

Thissen, R.; Somogyi, A.; Vuitton, V.; Bégué, D.; Lemaire, J.; Steinmetz, V.

2011-10-01

The complex organic material that is found on the surface and within the haze layer of Titan is attributed to chemistry occurring in its thick N2/CH4 atmosphere. Although several groups are producing in various laboratory setting the socalled tholins which have been investigated by using analytical methods including UV/Vis, fluorescence, IR, and MS1-5, these very complex organic mixtures still hold many unanswered questions, especially related to the potentiality for their prebiotic chemistry. In addition to tholins characterization and analysis, we recently investigated quantitatively the hydrolysis kinetics of tholins in pure and NH3 containing water at different temperatures.7-8 Our groups at UJF (Grenoble) and at U of Arizona (Tucson) have been collaborating on mass spectral analyses of tholins samples for several years.9 Here, we report our most recent results on the structural characterization of tholins by infrared multiphoton dissociation (IRMPD) action spectroscopy10 and ultrahigh resolution MS. IRMPD action spectroscopy is a recently developed technique that uses IR photons of variable wavelengths to activate ions trapped inside an ion trap. When photons are absorbed at a given wavelength, the selected ion fragments and this fragmentation is monitored as a function of wavelength, analog to an absorption spectrum (impossible to record otherwise because of the much reduced density). This technique can, therefore, be used to determine IR spectra of ions in the gas phase, and provides with very acute structural information. IRMPD action spectroscopy is often used to distinguish between structural isomers of isobaric ions. The drawback is that it requests for high power lasers. Only two Free Electron Lasers (FEL) are available in the world and allow to record spectra with reasonable resolution (20-25 cm-1). IRMPD action spectra of selected ions from tholins will be presented and discussed together with observed fragmentation processes that reveal structural

Application of the Raman spectroscopy for the characterization of organic pesticides

International Nuclear Information System (INIS)

Sato B, R.Y.; Medina G, C.; Medina V, J.; Frausto R, C.

2004-01-01

Raman spectra of organophosphate, organo chlorine and bipyridyl pesticides are presented in this study. They have been obtained satisfactorily by the NlR-Raman spectroscopy technique. Pesticides have been analyzed in solution or as a solid in glass containers and on aluminum substrates. This analytic technique can be an alternative tool for the detection of pesticides in the agriculture, presenting advantages as be quick, not destructive and require little or no sample preparation. Moreover, samples can be analyzed through transparent containers avoiding contact with the toxic substances. The implementation of the aluminium substrate is easy and practical. Moreover, it is commercially available and does not need a previous preparation. The analysis of a mixture of two pesticides in a β carotene solution is shown. (Author) 25 refs., 8 figs

Structural Characterization of Amadori Rearrangement Product of Glucosylated Nα-Acetyl-Lysine by Nuclear Magnetic Resonance Spectroscopy

Directory of Open Access Journals (Sweden)

Chuanjiang Li

2014-01-01

Full Text Available Maillard reaction is a nonenzymatic reaction between reducing sugars and free amino acid moieties, which is known as one of the most important modifications in food science. It is essential to characterize the structure of Amadori rearrangement products (ARPs formed in the early stage of Maillard reaction. In the present study, the Nα-acetyl-lysine-glucose model had been successfully set up to produce ARP, Nα-acetyl-lysine-glucose. After HPLC purification, ARP had been identified by ESI-MS with intense [M+H]+ ion at 351 m/z and the purity of ARP was confirmed to be over 90% by the relative intensity of [M+H]+ ion. Further structural characterization of the ARP was accomplished by using nuclear magnetic resonance (NMR spectroscopy, including 1D 1H NMR and 13C NMR, the distortionless enhancement by polarization transfer (DEPT-135 and 2D 1H-1H and 13C-1H correlation spectroscopy (COSY and 2D nuclear overhauser enhancement spectroscopy (NOESY. The complexity of 1D 1H NMR and 13C NMR was observed due to the presence of isomers in glucose moiety of ARP. However, DEPT-135 and 2D NMR techniques provided more structural information to assign the 1H and 13C resonances of ARP. 2D NOESY had successfully confirmed the glycosylated site between 10-N in Nα-acetyl-lysine and 7′-C in glucose.

Spectroscopy characterization and quantum yield determination of quantum dots

International Nuclear Information System (INIS)

Ortiz, S N Contreras; Ospino, E Mejía; Cabanzo, R

2016-01-01

In this paper we show the characterization of two kinds of quantum dots: hydrophilic and hydrophobic, with core and core/shell respectively, using spectroscopy techniques such as UV-Vis, fluorescence and Raman. We determined the quantum yield in the quantum dots using the quinine sulphate as standard. This salt is commonly used because of its quantum yield (56%) and stability. For the CdTe excitation, we used a wavelength of 549nm and for the CdSe/ZnS excitation a wavelength of 527nm. The results show that CdSe/ZnS (49%) has better fluorescence, better quantum dots, and confirm the fluorescence result. The quantum dots have shown a good fluorescence performance, so this property will be used to replace dyes, with the advantage that quantum dots are less toxic than some dyes like the rhodamine. In addition, in this work we show different techniques to find the quantum dots emission: fluorescence spectrum, synchronous spectrum and Raman spectrum. (paper)

Using Rutherford Backscattering Spectroscopy to Characterize Targets for MTW

Science.gov (United States)

Brown, Gunnar; Stockler, Barak; Ward, Ryan; Freeman, Charlie; Padalino, Stephen; Stillman, Collin; Ivancic, Steven; Reagan, S. P.; Sangster, T. C.

2017-10-01

A study is underway to determine the composition and thickness of targets used at the Multiterawatt (MTW) laser facility at the Laboratory for Laser Energetics (LLE) using Rutherford backscattering spectroscopy (RBS). In RBS, an ion beam is incident on a sample and the scattered ions are detected with a surface barrier detector. The resulting energy spectra of the scattered ions can be analyzed to determine important parameters of the target including elemental composition and thickness. Proton, helium and deuterium beams from the 1.7 MV Pelletron accelerator at SUNY Geneseo have been used to characterize several different targets for MTW, including CH and aluminum foils of varying thickness. RBS spectra were also obtained for a cylindrical iron buried-layer target with aluminum dopant which was mounted on a silicon carbide stalk. The computer program SIMNRA is used to analyze the spectra. This work was funded in part by a Grant from the DOE through the Laboratory for Laser Energetics.

Characterization of CdSe polycrystalline films by photoluminescence spectroscopy

International Nuclear Information System (INIS)

Brasil, M.J.S.P.

1985-01-01

The characterization of CdSe polycristalline films were done by photoluminescence spectroscopy, X-ray diffraction analysis, diagrams IxV, and efficiency of solar energy conversion for cells done by these films. The experimental data shown strong temperature dependence of annealing, and the optimum temperature around 650 0 C was determined. The films did not present photoluminescence before heat treatment, but the annealed sample spectrum showed fine structures in the excitonic region, crystal phase transformation, enhancement of grain size, and better efficiency of the cell. Measurements of photoluminescence between 2 and 300 K, showed two bands of infrared emission, width and intense enough. The shape, at half-width, and the integrated intensity of one these bands were described by a configuration coordinate model for deep centers. Based on obtained results, some hypothesis about the origin of these bands and its correlation with efficiency of cells done with CdSe polycrystalline films, are proposed. (M.C.K.) [pt

Fluorescence spectroscopy as a tool for determination of organic matter removal efficiency at water treatment works

Directory of Open Access Journals (Sweden)

M. Z. Bieroza

2010-04-01

Full Text Available Organic matter (OM in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products, and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterization and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission technique to OM characterization in drinking water treatment is presented. The fluorescence data of raw and clarified water was obtained from 16 drinking water treatment works. The reduction in fulvic-like fluorescence was found to significantly correlate with OM removal measured with total organic carbon (TOC. Fluorescence properties, fulvic- and tryptophan-like regions, were found to discriminate OM fractions of different removal efficiencies. The results obtained in the study show that fluorescence spectroscopy provides a rapid and accurate characterization and quantification of OM fractions and indication of their treatability in conventional water treatment.

Vibrational Spectroscopy of Ionic Liquids.

Science.gov (United States)

Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

2017-05-24

Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

Real-time in vivo tissue characterization with diffuse reflectance spectroscopy during transthoracic lung biopsy: a clinical feasibility study

NARCIS (Netherlands)

Spliethoff, Jarich; Prevoo, Warner; Meier, Mark A.J.; de Jong, Jeroen; Evers, Daniel; Evers, Daniel J.; Sterenborg, Hendricus J.C.M.; Lucassen, Gerald; Lucassen, Gerald W.; Hendriks, Benno H.W.; Ruers, Theo J.M.

2016-01-01

Purpose: This study presents the first in vivo real-time tissue characterization during image-guided percutaneous lung biopsies using diffuse reflectance spectroscopy (DRS) sensing at the tip of a biopsy needle with integrated optical fibers. Experimental Design: Tissues from 21 consented patients

X-ray spectroscopy from exotic atoms

International Nuclear Information System (INIS)

Hartmann, F.J.

1994-01-01

Why do experimentalists study exotic atoms, in particular antiprotonic atoms? The answer is simple: the information about electromagnetic, weak, and strong interactions that can be obtained by doing X-ray spectroscopy from exotic atoms is really worth the effort. It is possible to (1) enlarge the knowledge about the properties of exotic particles (such as mass and magnetic moment); (2) open a possibility to test quantum electrodynamics; (3) get detailed insight into the shape of nuclei (characterized by the nuclear radium and higher momenta) and even into the neutron distribution in the nucleus (neutron halo); and (4) use it as a powerful tool to learn about the strong interaction at very low relative hadron-nucleon velocities

Moessbauer spectroscopy as a tool in astrobiology

Energy Technology Data Exchange (ETDEWEB)

Schroeder, Christian, E-mail: schroedc@uni-mainz.de; Klingelhoefer, Goestar, E-mail: klingel@mail.uni-mainz.de [Johannes Gutenberg-Universitaet, Institut fuer Anorganische Chemie und Analytische Chemie (Germany); Bailey, Brad E., E-mail: bebailey@ucsd.edu; Staudigel, Hubert, E-mail: hstaudigel@ucsd.edu [University of California San Diego, Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography (United States)

2005-11-15

Two miniaturized Moessbauer spectrometers are part of the Athena instrument package of the NASA Mars Exploration Rovers, Spirit and Opportunity. The primary objectives of their science investigation are to explore two sites on the surface of Mars where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life. Aqueous minerals - jarosite at Meridiani Planum, Opportunity's landing site, and goethite in the Columbia Hills in Gusev Crater, Spirit's landing site - were identified by Moessbauer spectroscopy, thus providing in situ proof of water being present at those sites in the past. The formation of jarosite in particular puts strong constraints on environmental conditions during the time of formation and hence on the evaluation of potential habitability. On Earth Moessbauer spectroscopy was used to investigate microbially induced changes in Fe oxidation states and mineralogy at the Loihi deep sea mount, a hydrothermal vent system, which might serve as an analogue for potential habitats in the Martian subsurface and the sub-ice ocean of Jupiter's icy moon Europa.

Moessbauer spectroscopy as a tool in astrobiology

International Nuclear Information System (INIS)

Schroeder, Christian; Klingelhoefer, Goestar; Bailey, Brad E.; Staudigel, Hubert

2005-01-01

Two miniaturized Moessbauer spectrometers are part of the Athena instrument package of the NASA Mars Exploration Rovers, Spirit and Opportunity. The primary objectives of their science investigation are to explore two sites on the surface of Mars where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life. Aqueous minerals - jarosite at Meridiani Planum, Opportunity's landing site, and goethite in the Columbia Hills in Gusev Crater, Spirit's landing site - were identified by Moessbauer spectroscopy, thus providing in situ proof of water being present at those sites in the past. The formation of jarosite in particular puts strong constraints on environmental conditions during the time of formation and hence on the evaluation of potential habitability. On Earth Moessbauer spectroscopy was used to investigate microbially induced changes in Fe oxidation states and mineralogy at the Loihi deep sea mount, a hydrothermal vent system, which might serve as an analogue for potential habitats in the Martian subsurface and the sub-ice ocean of Jupiter's icy moon Europa.

Formation and characterization of varied size germanium nanocrystals by electron microscopy, Raman spectroscopy, and photoluminescence

DEFF Research Database (Denmark)

Ou, Haiyan; Ou, Yiyu; Liu, Chuan

2011-01-01

Germanium nanocrystals are being extensively examined. Their unique optical properties (brought about by the quantum confinement effect) could potentially be applied in wide areas of nonlinear optics, light emission and solid state memory etc. In this paper, Ge nanocrystals embedded in a SiO2...... matrix were formed by complementary metal-oxide-semiconductor compatible technology, e.g. plasma enhanced chemical vapour deposition and annealing. Different sizes of the Ge nanocrystals were prepared and analyzed by transmission electron microscopy with respect to their size, distribution...... and crystallization. The samples of different size Ge nanocrystals embedded in the SiO2 matrix were characterized by Raman spectroscopy and photoluminescence. Interplayed size and strain effect of Ge nanocystals was demonstrated by Raman spectroscopy after excluding the thermal effect with proper excitation laser...

Structural characterization of chemical warfare agent degradation products in decontamination solutions with proton band-selective (1)H-(31)P NMR spectroscopy.

Science.gov (United States)

Koskela, Harri; Hakala, Ullastiina; Vanninen, Paula

2010-06-15

Decontamination solutions, which are usually composed of strong alkaline chemicals, are used for efficient detoxification of chemical warfare agents (CWAs). The analysis of CWA degradation products directly in decontamination solutions is challenging due to the nature of the matrix. Furthermore, occasionally an unforeseen degradation pathway can result in degradation products which could be eluded to in standard analyses. Here, we present the results of the application of proton band-selective (1)H-(31)P NMR spectroscopy, i.e., band-selective 1D (1)H-(31)P heteronuclear single quantum coherence (HSQC) and band-selective 2D (1)H-(31)P HSQC-total correlation spectroscopy (TOCSY), for ester side chain characterization of organophosphorus nerve agent degradation products in decontamination solutions. The viability of the approach is demonstrated with a test mixture of typical degradation products of nerve agents sarin, soman, and VX. The proton band-selective (1)H-(31)P NMR spectroscopy is also applied in characterization of unusual degradation products of VX in GDS 2000 solution.

High-precision multiband spectroscopy of ultracold fermions in a nonseparable optical lattice

Science.gov (United States)

Fläschner, Nick; Tarnowski, Matthias; Rem, Benno S.; Vogel, Dominik; Sengstock, Klaus; Weitenberg, Christof

2018-05-01

Spectroscopic tools are fundamental for the understanding of complex quantum systems. Here, we demonstrate high-precision multiband spectroscopy in a graphenelike lattice using ultracold fermionic atoms. From the measured band structure, we characterize the underlying lattice potential with a relative error of 1.2 ×10-3 . Such a precise characterization of complex lattice potentials is an important step towards precision measurements of quantum many-body systems. Furthermore, we explain the excitation strengths into different bands with a model and experimentally study their dependency on the symmetry of the perturbation operator. This insight suggests the excitation strengths as a suitable observable for interaction effects on the eigenstates.

Rapid detection of foodborne microorganisms on food surface using Fourier transform Raman spectroscopy

Science.gov (United States)

Yang, Hong; Irudayaraj, Joseph

2003-02-01

Fourier transform (FT) Raman spectroscopy was used for non-destructive characterization and differentiation of six different microorganisms including the pathogen Escherichia coli O157:H7 on whole apples. Mahalanobis distance metric was used to evaluate and quantify the statistical differences between the spectra of six different microorganisms. The same procedure was extended to discriminate six different strains of E. coli. The FT-Raman procedure was not only successful in discriminating the different E. coli strain but also accurately differentiated the pathogen from non-pathogens. Results demonstrate that FT-Raman spectroscopy can be an excellent tool for rapid examination of food surfaces for microorganism contamination and for the classification of microbial cultures.

Intelligent sensing sensory quality of Chinese rice wine using near infrared spectroscopy and nonlinear tools

Science.gov (United States)

Ouyang, Qin; Chen, Quansheng; Zhao, Jiewen

2016-02-01

The approach presented herein reports the application of near infrared (NIR) spectroscopy, in contrast with human sensory panel, as a tool for estimating Chinese rice wine quality; concretely, to achieve the prediction of the overall sensory scores assigned by the trained sensory panel. Back propagation artificial neural network (BPANN) combined with adaptive boosting (AdaBoost) algorithm, namely BP-AdaBoost, as a novel nonlinear algorithm, was proposed in modeling. First, the optimal spectra intervals were selected by synergy interval partial least square (Si-PLS). Then, BP-AdaBoost model based on the optimal spectra intervals was established, called Si-BP-AdaBoost model. These models were optimized by cross validation, and the performance of each final model was evaluated according to correlation coefficient (Rp) and root mean square error of prediction (RMSEP) in prediction set. Si-BP-AdaBoost showed excellent performance in comparison with other models. The best Si-BP-AdaBoost model was achieved with Rp = 0.9180 and RMSEP = 2.23 in the prediction set. It was concluded that NIR spectroscopy combined with Si-BP-AdaBoost was an appropriate method for the prediction of the sensory quality in Chinese rice wine.

Tissue characterization using electrical impedance spectroscopy data: a linear algebra approach.

Science.gov (United States)

Laufer, Shlomi; Solomon, Stephen B; Rubinsky, Boris

2012-06-01

In this study, we use a new linear algebra manipulation on electrical impedance spectroscopy measurements to provide real-time information regarding the nature of the tissue surrounding the needle in minimal invasive procedures. Using a Comsol Multiphysics three-dimensional model, a phantom based on ex vivo animal tissue and in vivo animal data, we demonstrate how tissue inhomogeneity can be characterized without any previous knowledge of the electrical properties of the different tissues, except that they should not be linearly dependent on a certain frequency range. This method may have applications in needle biopsies, radiation seeds, or minimally invasive surgery and can reduce the number of computer tomography or magnetic resonance imaging images. We conclude by demonstrating how this mathematical approach can be useful in other applications.

Raman Spectroscopy: An Emerging Tool in Neurodegenerative Disease Research and Diagnosis.

Science.gov (United States)

Devitt, George; Howard, Kelly; Mudher, Amrit; Mahajan, Sumeet

2018-03-21

The pathogenesis underlining many neurodegenerative diseases remains incompletely understood. The lack of effective biomarkers and disease preventative medicine demands the development of new techniques to efficiently probe the mechanisms of disease and to detect early biomarkers predictive of disease onset. Raman spectroscopy is an established technique that allows the label-free fingerprinting and imaging of molecules based on their chemical constitution and structure. While analysis of isolated biological molecules has been widespread in the chemical community, applications of Raman spectroscopy to study clinically relevant biological species, disease pathogenesis, and diagnosis have been rapidly increasing since the past decade. The growing number of biomedical applications has shown the potential of Raman spectroscopy for detection of novel biomarkers that could enable the rapid and accurate screening of disease susceptibility and onset. Here we provide an overview of Raman spectroscopy and related techniques and their application to neurodegenerative diseases. We further discuss their potential utility in research, biomarker detection, and diagnosis. Challenges to routine use of Raman spectroscopy in the context of neuroscience research are also presented.

Measurement and Characterization of Hydrogen-Deuterium Exchange Chemistry Using Relaxation Dispersion NMR Spectroscopy.

Science.gov (United States)

Khirich, Gennady; Holliday, Michael J; Lin, Jasper C; Nandy, Aditya

2018-03-01

One-dimensional heteronuclear relaxation dispersion NMR spectroscopy at 13 C natural abundance successfully characterized the dynamics of the hydrogen-deuterium exchange reaction occurring at the N ε position in l-arginine by monitoring C δ in varying amounts of D 2 O. A small equilibrium isotope effect was observed and quantified, corresponding to ΔG = -0.14 kcal mol -1 . A bimolecular rate constant of k D = 5.1 × 10 9 s -1 M -1 was determined from the pH*-dependence of k ex (where pH* is the direct electrode reading of pH in 10% D 2 O and k ex is the nuclear spin exchange rate constant), consistent with diffusion-controlled kinetics. The measurement of ΔG serves to bridge the millisecond time scale lifetimes of the detectable positively charged arginine species with the nanosecond time scale lifetime of the nonobservable low-populated neutral arginine intermediate species, thus allowing for characterization of the equilibrium lifetimes of the various arginine species in solution as a function of fractional solvent deuterium content. Despite the system being in fast exchange on the chemical shift time scale, the magnitude of the secondary isotope shift due to the exchange reaction at N ε was accurately measured to be 0.12 ppm directly from curve-fitting D 2 O-dependent dispersion data collected at a single static field strength. These results indicate that relaxation dispersion NMR spectroscopy is a robust and general method for studying base-catalyzed hydrogen-deuterium exchange chemistry at equilibrium.

Optical properties and extinction spectroscopy to characterize the synthesis of amine capped silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Roldan, Maria Virginia [Laboratorio de Materiales Ceramicos, FCEIyA, IFIR, UNR, Rosario (Argentina)], E-mail: vroldan@fceia.unr.edu.ar; Scaffardi, Lucia B. [CIOp - CONICET, CIC, c.c. 124, 1900 La Plata (Argentina) and Area Departamental de Ciencias Basicas, Facultad de Ingenieria, Universidad Nacional de La Plata, La Plata (Argentina); Sanctis, Oscar de [Laboratorio de Materiales Ceramicos, FCEIyA, IFIR, UNR, Rosario (Argentina); Pellegri, Nora [Laboratorio de Materiales Ceramicos, FCEIyA, IFIR, UNR, Rosario (Argentina)], E-mail: pellegri@fceia.unr.edu.ar

2008-12-20

The present work describes a method for preparation of Ag nanoparticles from chemical reduction of AgNO{sub 3} in ethanol with ATS [N-[3-(trimethoxysilyl)propyl] diethylenetriamine] as surface modifier. We study the influence of different parameters such as concentration, time, temperature and reductor agents on the size and shape of the nanoparticles. We present the morphologic and structural characterization of samples by UV-vis extinction spectroscopy, Atomic Force Microscopy (AFM) and X-ray diffraction (XRD). Particularly, using optical extinction spectroscopy, the present work shows the analysis of size evolution in the fabrication process of spherical silver nanoparticles. This evolution is studied as a function of the time elapsed between the beginning of the reaction and the extraction of the sample (temporal delayed synthesis), and as a function of the temperature during the chemical reaction. In both the cases, we propose the study of the plasmon width as a useful, simple and inexpensive method for analysis of the mean radius, specially, for values below 6 nm.

Optical properties and extinction spectroscopy to characterize the synthesis of amine capped silver nanoparticles

International Nuclear Information System (INIS)

Roldan, Maria Virginia; Scaffardi, Lucia B.; Sanctis, Oscar de; Pellegri, Nora

2008-01-01

The present work describes a method for preparation of Ag nanoparticles from chemical reduction of AgNO 3 in ethanol with ATS [N-[3-(trimethoxysilyl)propyl] diethylenetriamine] as surface modifier. We study the influence of different parameters such as concentration, time, temperature and reductor agents on the size and shape of the nanoparticles. We present the morphologic and structural characterization of samples by UV-vis extinction spectroscopy, Atomic Force Microscopy (AFM) and X-ray diffraction (XRD). Particularly, using optical extinction spectroscopy, the present work shows the analysis of size evolution in the fabrication process of spherical silver nanoparticles. This evolution is studied as a function of the time elapsed between the beginning of the reaction and the extraction of the sample (temporal delayed synthesis), and as a function of the temperature during the chemical reaction. In both the cases, we propose the study of the plasmon width as a useful, simple and inexpensive method for analysis of the mean radius, specially, for values below 6 nm

Selecting analytical tools for characterization of polymersomes in aqueous solution

DEFF Research Database (Denmark)

Habel, Joachim Erich Otto; Ogbonna, Anayo; Larsen, Nanna

2015-01-01

Selecting the appropriate analytical methods for characterizing the assembly and morphology of polymer-based vesicles, or polymersomes are required to reach their full potential in biotechnology. This work presents and compares 17 different techniques for their ability to adequately report size....../purification. Of the analytical methods tested, Cryo-transmission electron microscopy and atomic force microscopy (AFM) turned out to be advantageous for polymersomes with smaller diameter than 200 nm, whereas confocal microscopy is ideal for diameters >400 nm. Polymersomes in the intermediate diameter range can be characterized...... using freeze fracture Cryo-scanning electron microscopy (FF-Cryo-SEM) and nanoparticle tracking analysis (NTA). Small angle X-ray scattering (SAXS) provides reliable data on bilayer thickness and internal structure, Cryo-TEM on multilamellarity. Taken together, these tools are valuable...

Development and analysis of spectroscopic learning tools and the light and spectroscopy concept inventory for introductory college astronomy

Science.gov (United States)

Bardar, Erin M.

Electromagnetic radiation is the fundamental carrier of astronomical information. Spectral features serve as the fingerprints of the universe, revealing many important properties of objects in the cosmos such as temperature, elemental compositions, and relative motion. Because of its importance to astronomical research, the nature of light and the electromagnetic spectrum is by far the most universally covered topic in astronomy education. Yet, to the surprise and disappointment of instructors, many students struggle to understand underlying fundamental concepts related to light and spectroscopic phenomena. This dissertation describes research into introductory college astronomy students' understanding of light and spectroscopy concepts, through the development and analysis of both instructional materials and an assessment instrument. The purpose of this research was two-fold: (1) to develop a novel suite of spectroscopic learning tools that enhance student understanding of light and spectroscopy and (2) to design and validate a Light and Spectroscopy Concept Inventory (LSCI) with the sensitivity to distinguish the relative effectiveness of various teaching interventions within the context of introductory college astronomy. Through a systematic investigation that included multiple rounds of clinical interviews, open-ended written surveys, and multiple-choice testing, introductory college astronomy students' commonly held misconceptions and reasoning difficulties were explored for concepts relating to: (1) The nature of the electromagnetic spectrum, including the interrelationships of wavelength, frequency, energy, and speed; (2) interpretation of Doppler shift; (3) properties of blackbody radiation; and (4) the connection between spectral features and underlying physical processes. These difficulties guided the development of instructional materials including six unique "homelab" exercises, a binocular spectrometer, a spectral analysis software tool, and the 26

Study of human brain functions by functional magnetic resonance imaging (fMRI) and spectroscopy (fMRS)

International Nuclear Information System (INIS)

Jagannathan, N.R.

1998-01-01

Functional magnetic resonance imaging (fMRI) has become a powerful tool in the detection and assessment of cerebral pathophysiology and the regional mapping and characterization of cognitive processes such as motor skills, vision, language and memory. The results of the effect of motor cortex stimulation during repetitive hand squeezing task activation using in-vivo single voxel NMR spectroscopy carried out on normal volunteer subjects are presented

Probing defect states in polycrystalline GaN grown on Si(111) by sub-bandgap laser-excited scanning tunneling spectroscopy

Science.gov (United States)

Hsiao, F.-M.; Schnedler, M.; Portz, V.; Huang, Y.-C.; Huang, B.-C.; Shih, M.-C.; Chang, C.-W.; Tu, L.-W.; Eisele, H.; Dunin-Borkowski, R. E.; Ebert, Ph.; Chiu, Y.-P.

2017-01-01

We demonstrate the potential of sub-bandgap laser-excited cross-sectional scanning tunneling microscopy and spectroscopy to investigate the presence of defect states in semiconductors. The characterization method is illustrated on GaN layers grown on Si(111) substrates without intentional buffer layers. According to high-resolution transmission electron microscopy and cathodoluminescence spectroscopy, the GaN layers consist of nanoscale wurtzite and zincblende crystallites with varying crystal orientations and hence contain high defect state densities. In order to discriminate between band-to-band excitation and defect state excitations, we use sub-bandgap laser excitation. We probe a clear increase in the tunnel current at positive sample voltages during sub-bandgap laser illumination for the GaN layer with high defect density, but no effect is found for high quality GaN epitaxial layers. This demonstrates the excitation of free charge carriers at defect states. Thus, sub-bandgap laser-excited scanning tunneling spectroscopy is a powerful complimentary characterization tool for defect states.

Characterization of un-irradiated MIMAS MOX fuel by Raman spectroscopy and EPMA

Science.gov (United States)

Talip, Zeynep; Peuget, Sylvain; Magnin, Magali; Tribet, Magaly; Valot, Christophe; Vauchy, Romain; Jégou, Christophe

2018-02-01

In this study, Raman spectroscopy technique was implemented to characterize un-irradiated MIMAS (MIcronized - MASter blend) MOX fuel samples with average 7 wt.% Pu content and different damage levels, 13 years after fabrication, one year after thermal recovery and soon after annealing, respectively. The impacts of local Pu content, deviation from stoichiometry and self-radiation damage on Raman spectrum of the studied MIMAS MOX samples were assessed. MIMAS MOX fuel has three different phases Pu-rich agglomerate, coating phase and uranium matrix. In order to distinguish these phases, Raman results were associated with Pu content measurements performed by Electron Microprobe Analysis. Raman results show that T2g frequency significantly shifts from 445 to 453 cm-1 for Pu contents increasing from 0.2 to 25 wt.%. These data are satisfactorily consistent with the calculations obtained with Gruneisen parameters. It was concluded that the position of the T2g band is mainly controlled by Pu content and self-radiation damage. Deviation from stoichiometry does not have a significant influence on T2g band position. Self-radiation damage leads to a shift of T2g band towards lower frequency (∼1-2 cm-1 for the UO2 matrix of damaged sample). However, this shift is difficult to quantify for the coating phase and Pu agglomerates given the dispersion of high Pu concentrations. In addition, 525 cm-1 band, which was attributed to sub-stoichiometric structural defects, is presented for the first time for the self-radiation damaged MOX sample. Thanks to the different oxidation resistance of each phase, it was shown that laser induced oxidation could be alternatively used to identify the phases. It is demonstrated that micro-Raman spectroscopy is an efficient technique for the characterization of heterogeneous MOX samples, due to its low spatial resolution.

Instrument for x-ray absorption spectroscopy with in situ electrical control characterizations

International Nuclear Information System (INIS)

Huang, Chun-Chao; Chang, Shu-Jui; Yang, Chao-Yao; Tseng, Yuan-Chieh; Chou, Hsiung

2013-01-01

We report a synchrotron-based setup capable of performing x-ray absorption spectroscopy and x-ray magnetic circular dichroism with simultaneous electrical control characterizations. The setup can enable research concerning electrical transport, element- and orbital-selective magnetization with an in situ fashion. It is a unique approach to the real-time change of spin-polarized electronic state of a material/device exhibiting magneto-electric responses. The performance of the setup was tested by probing the spin-polarized states of cobalt and oxygen of Zn 1-x Co x O dilute magnetic semiconductor under applied voltages, both at low (∼20 K) and room temperatures, and signal variations upon the change of applied voltage were clearly detected

Purity and Defect Characterization of Single-Wall Carbon Nanotubes Using Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Yasumitsu Miyata

2011-01-01

Full Text Available We investigated the purity and defects of single-wall carbon nanotubes (SWCNTs produced by various synthetic methods including chemical vapor deposition, arc discharge, and laser ablation. The SWCNT samples were characterized using scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and Raman spectroscopy. Quantitative analysis of SEM images suggested that the G-band Raman intensity serves as an index for the purity. By contrast, the intensity ratio of G-band to D-band (G/D ratio reflects both the purity and the defect density of SWCNTs. The combination of G-band intensity and G/D ratio is useful for a quick, nondestructive evaluation of the purity and defect density of a SWCNT sample.

Tissue characterization using electrical impedance spectroscopy data: a linear algebra approach

International Nuclear Information System (INIS)

Laufer, Shlomi; Solomon, Stephen B; Rubinsky, Boris

2012-01-01

In this study, we use a new linear algebra manipulation on electrical impedance spectroscopy measurements to provide real-time information regarding the nature of the tissue surrounding the needle in minimal invasive procedures. Using a Comsol Multiphysics three-dimensional model, a phantom based on ex vivo animal tissue and in vivo animal data, we demonstrate how tissue inhomogeneity can be characterized without any previous knowledge of the electrical properties of the different tissues, except that they should not be linearly dependent on a certain frequency range. This method may have applications in needle biopsies, radiation seeds, or minimally invasive surgery and can reduce the number of computer tomography or magnetic resonance imaging images. We conclude by demonstrating how this mathematical approach can be useful in other applications. (paper)

Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

Energy Technology Data Exchange (ETDEWEB)

Varela, J.A.; Amado, J.M.; Tobar, M.J.; Mateo, M.P.; Yañez, A.; Nicolas, G., E-mail: gines@udc.es

2015-05-01

Highlights: • Chemical mapping and profiling by laser-induced breakdown spectroscopy (LIBS) of coatings produced by laser cladding. • Production of laser clads using tungsten carbide (WC) and nickel based matrix (NiCrBSi) powders. • Calibration by LIBS of hardfacing alloys with different WC concentrations. - Abstract: Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

Imaging spectroscopy for characterisation of grass swards

NARCIS (Netherlands)

Schut, A.G.T.

2003-01-01

Keywords: Imaging spectroscopy, imaging spectrometry, remote sensing, reflection, reflectance, grass sward, white clover, recognition, characterisation, ground cover, growth monitoring, stress detection, heterogeneity quantification

The potential of imaging spectroscopy as a tool for

Characterization by acoustic emission and electrochemical impedance spectroscopy of the cathodic disbonding of Zn coating

International Nuclear Information System (INIS)

Amami, Souhail; Lemaitre, Christian; Laksimi, Abdelouahed; Benmedakhene, Salim

2010-01-01

Galvanized steel has been tested in a synthetic sea water solution under different cathodic overprotection conditions. The generated hydrogen flux caused the damage of the metal-zinc interface and led to a progressive coating detachment. Scanning electron microscopy, electrochemical impedance spectroscopy and acoustic emission technique were used to characterize the damage chronology under different cathodic potentials. A damage mechanism was proposed and the acoustic signature related to the coating degradation was statistically identified using clustering techniques.

Characterization by acoustic emission and electrochemical impedance spectroscopy of the cathodic disbonding of Zn coating

Energy Technology Data Exchange (ETDEWEB)

Amami, Souhail [Universite de Technologie de Compiegne, Departement de Genie Mecanique, Laboratoire Roberval, UMR 6066 du CNRS, B.P. 20529, 60206 Compiegne Cedex (France)], E-mail: souhail.amami@utc.fr; Lemaitre, Christian; Laksimi, Abdelouahed; Benmedakhene, Salim [Universite de Technologie de Compiegne, Departement de Genie Mecanique, Laboratoire Roberval, UMR 6066 du CNRS, B.P. 20529, 60206 Compiegne Cedex (France)

2010-05-15

Galvanized steel has been tested in a synthetic sea water solution under different cathodic overprotection conditions. The generated hydrogen flux caused the damage of the metal-zinc interface and led to a progressive coating detachment. Scanning electron microscopy, electrochemical impedance spectroscopy and acoustic emission technique were used to characterize the damage chronology under different cathodic potentials. A damage mechanism was proposed and the acoustic signature related to the coating degradation was statistically identified using clustering techniques.

Experimental and Numerical Characterization of a Pulsed Supersonic Uniform Flow for Kinetics and Spectroscopy

Science.gov (United States)

Suas-David, Nicolas; Thawoos, Shameemah; Broderick, Bernadette M.; Suits, Arthur

2017-06-01

The current CPUF (Chirped Pulse Uniform Flow) and the new UF-CRDS (Uniform Flow Cavity Ring-Down Spectroscopy) setups relie mostly on the production of a good quality supersonic uniform flow. A supersonic uniform flow is produced by expanding a gas through a Laval nozzle - similar to the nozzles used in aeronautics - linked to a vacuum chamber. The expansion is characterized by an isentropic core where constant very low kinetic temperature (down to 20K) and constant density are observed. The relatively large diameter of the isentropic core associated with homogeneous thermodynamic conditions makes it a relevant tool for low temperature spectroscopy. On the other hand, the length along the axis of the flow of this core (could be longer than 50cm) allows kinetic studies which is one of the main interest of this setup (CRESU technique. The formation of a uniform flow requires an extreme accuracy in the design of the shape of the nozzle for a set of defined temperature/density. The design is based on a Matlab program which retrieves the shape of the isentropic core according to the method of characteristics prior to calculate the thickness of the boundary layer. Two different approaches are used to test the viability of a new nozzle derived from the program. First, a computational fluid dynamic software (OpenFOAM) models the distribution of the thermodynamic properties of the expansion. Then, fabricated nozzles using 3-D printing are tested based on Pitot measurements and spectroscopic analyses. I will present comparisons of simulation and measured performance for a range of nozzles. We will see how the high level of accuracy of numerical simulations provides a deeper knowledge of the experimental conditions. J. M. Oldham, C. Abeysekera, J. Joalland, L. N. Zack, K. Prozument, I. R. Sims, G. Barrat Park, R. W. Filed and A. G. Suits, J. Chem. Phys. 141, 154202, (2014). I. Sims, J. L. Queffelec, A. Defrance, C. Rebrion-Rowe, D. Travers, P. Bocherel, B. Rowe, I. W. Smith

Intracavity Faraday modulation spectroscopy (INFAMOS): A tool for radical detection

Science.gov (United States)

Gianella, Michele; Pinto, Tomas H. P.; Wu, Xia; Ritchie, Grant A. D.

2017-08-01

We present the intra-cavity Faraday modulation spectroscopy technique, whereby optical feedback cavity-enhanced spectroscopy is coupled with Faraday modulation spectroscopy to greatly enhance the interaction path length of a laser beam with a paramagnetic sample in a magnetic field. We describe a first prototype based upon a cw quantum cascade laser targeting a selection of fundamental rovibrational R-branch transitions of nitric oxide (1890 cm-1), consisting of a linear cavity (finesse F =6300 ) and a water-cooled solenoid. We demonstrate a minimum detectable Verdet constant of Vmin=4.7 ×10-14 rad cm-1 G-1 H z-1/2 (at SNR = 1), corresponding to a single-pass rotation angle of 1.6 ×10-10 rad Hz-1/2 and a limit of detection of 0.21 ppbv Hz-1/2 NO.

Intracavity Faraday modulation spectroscopy (INFAMOS): A tool for radical detection.

Science.gov (United States)

Gianella, Michele; Pinto, Tomas H P; Wu, Xia; Ritchie, Grant A D

2017-08-07

We present the intra-cavity Faraday modulation spectroscopy technique, whereby optical feedback cavity-enhanced spectroscopy is coupled with Faraday modulation spectroscopy to greatly enhance the interaction path length of a laser beam with a paramagnetic sample in a magnetic field. We describe a first prototype based upon a cw quantum cascade laser targeting a selection of fundamental rovibrational R-branch transitions of nitric oxide (1890 cm -1 ), consisting of a linear cavity (finesse F=6300) and a water-cooled solenoid. We demonstrate a minimum detectable Verdet constant of V min =4.7×10 -14  rad cm -1  G -1  Hz -1/2 (at SNR = 1), corresponding to a single-pass rotation angle of 1.6×10 -10  rad Hz -1/2 and a limit of detection of 0.21 ppbv Hz -1/2 NO.

Characterization of cinematographic films by Laser Induced Breakdown Spectroscopy

International Nuclear Information System (INIS)

Gaspard, S.; Oujja, M.; Rebollar, E.; Abrusci, C.; Catalina, F.; Castillejo, M.

2007-01-01

The emulsion-coated transparent plastic-base film has been the main carrier for production and preservation of motion picture contents since the 19th century. The knowledge of the composition of black and white silver gelatine cinematographic films is of great importance for the characterization of the photographic process and for identifying the optimum conditions for conservation. A cinematographic film is a multi-component system that consists of a layer of photographic emulsion overcoating a polymeric support (plasticized cellulose triacetate) and a protective transparent cross-linked gelatine layer coating the emulsion. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) is used to characterize the composition of the materials of cinematographic films. LIB spectra of film samples and of different individual film components, polymeric support and reference gelatines, were acquired in vacuum by excitation at 266 nm (Q-switched Nd:YAG laser, 6 ns, 10 Hz). In the cinematographic film, silver lines from the light-sensitive silver halide salts of the photographic emulsion are accompanied by iron, lead, chrome and phosphorus lines. Iron and lead are constituents of film developers, chrome is included in the composition of the hardening agents and phosphorus has its origin in the plasticizer used in the polymeric support. By applying successive pulses on the same spot of the film sample, it was possible to observe through stratigraphic analysis the different layers composition. Additionally, the results obtained reveal the analytical capacity of LIBS for the study and classification of the different gelatine types and qualities used for the protecting layer and the photographic emulsion

Spectroscopy of scattered light for the characterization of micro and nanoscale objects in biology and medicine.

Science.gov (United States)

Turzhitsky, Vladimir; Qiu, Le; Itzkan, Irving; Novikov, Andrei A; Kotelev, Mikhail S; Getmanskiy, Michael; Vinokurov, Vladimir A; Muradov, Alexander V; Perelman, Lev T

2014-01-01

The biomedical uses for the spectroscopy of scattered light by micro and nanoscale objects can broadly be classified into two areas. The first, often called light scattering spectroscopy (LSS), deals with light scattered by dielectric particles, such as cellular and sub-cellular organelles, and is employed to measure their size or other physical characteristics. Examples include the use of LSS to measure the size distributions of nuclei or mitochondria. The native contrast that is achieved with LSS can serve as a non-invasive diagnostic and scientific tool. The other area for the use of the spectroscopy of scattered light in biology and medicine involves using conducting metal nanoparticles to obtain either contrast or electric field enhancement through the effect of the surface plasmon resonance (SPR). Gold and silver metal nanoparticles are non-toxic, they do not photobleach, are relatively inexpensive, are wavelength-tunable, and can be labeled with antibodies. This makes them very promising candidates for spectrally encoded molecular imaging. Metal nanoparticles can also serve as electric field enhancers of Raman signals. Surface enhanced Raman spectroscopy (SERS) is a powerful method for detecting and identifying molecules down to single molecule concentrations. In this review, we will concentrate on the common physical principles, which allow one to understand these apparently different areas using similar physical and mathematical approaches. We will also describe the major advancements in each of these areas, as well as some of the exciting recent developments.

Applications of the Raman spectroscopy in the materials characterization; Aplicaciones de la espectroscopia Raman en la caracterizacion de materiales

Energy Technology Data Exchange (ETDEWEB)

Jimenez S, S. (ed.) [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Queretaro (Mexico); Escobar A, L. (ed.) [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Camacho L, M. A. (ed.) [Universidad Autonoma del Estado de Mexico, Instituto Literario No. 100, Col. Centro, 50000 Toluca, Estado de Mexico (Mexico)

2011-07-01

The study field of the science and technology of surfaces and materials have been of primordial importance in the last years due to the impact that they have the knowledge that it generates in diverse areas. For this reason, the Mexican Society of Science and Technology of Surfaces and Materials has focused a good part of their investigation activities toward the materials science and technology development. Inside the investigation fields carried out by members of this Society, are the following: semiconductors, thin films, hard coatings, deposit techniques, plasmas, biomaterials, Ab-initio calculations, characterization techniques, photo-thermal properties, solar cells, nano science, magnetism, superconductivity and related topics. Among the techniques used for this purpose is the Raman Spectroscopy (Rs), which has demonstrated to be a powerful and versatile tool in the materials study. In the last three congresses that the Society has organized, an average of 42 works related with this topic have been presented, what gave the rule to prepare this book whose objective is on one hand diffusing part of the works that carry out different groups integrated with members of the Society that use the Rs like an important tool in its investigation work. A second objective is that it can serve like support to the students that begin to be involved, or that they are already involved, in topics where the Rs can have a decisive paper in the development of its projects. It is also expected that some of the topics included in the book are of utility for professors and researches that already uses the Rs, or that it can be of help for those who are beginning in this technique as alternative or like complementary analysis tool. (Author)

Identification of inks and structural characterization of contemporary artistic prints by laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Oujja, M.; Vila, A.; Rebollar, E.; Garcia, J.F.; Castillejo, M.

2005-01-01

Identification of the inks used in artistic prints and the order in which different ink layers have been applied on a paper substrate are important factors to complement the classical stylistic aspects for the authentication of this type of objects. Laser-induced breakdown spectroscopy (LIBS) is investigated to determine the chemical composition and structural distribution of the constituent materials of model prints made by applying one or two layers of several blue and black inks on an Arches paper substrate. By using suitable laser excitation conditions, identification of the inks was possible by virtue of emissions from key elements present in their composition. Analysis of successive spectra on the same spot allowed the identification of the order in which the inks were applied on the paper. The results show the potential of laser-induced breakdown spectroscopy for the chemical and structural characterization of artistic prints

Characterization of human breast disease using phosphorus magnetic resonance spectroscopy and proton magnetic resonance imaging

International Nuclear Information System (INIS)

Merchant, T.E.

1992-01-01

This thesis provides the fundamental characterization and differentiation of breast tissues using in vivo and ex vivo MR techniques in the hope that these techniques and experimental findings will be used on a larger scale and in a predictive manner in order to improve the specificity of diagnosis and treatment of breast cancer. In this dissertation, clinical studies were performed using proton magnetic resonance imaging and phosphorus magnetic resonance spectro-scopy ( 31 P MRS) to characterize and differentiate malignant breast tumors, benign breast tumors and normal breast tissues in vivo. These studies were carried out following the methodical characterization of chemical extracts of malignant breast tumor, benign breast tumor and normal breast parenchymal surgical tissue specimens using high resolution 31 P MRS. Alterations in breast tissue metabolism, as a result of pathological processes, were postulated to be responsible for measurable differences between malignant breast tumors, benign breast tumors and normal breast tissues using magnetic resonance techniques. (author). 365 refs.; 37 figs.; 25 tabs

Direct characterization of the energy level alignments and molecular components in an organic hetero-junction by integrated photoemission spectroscopy and reflection electron energy loss spectroscopy analysis.

Science.gov (United States)

Yun, Dong-Jin; Shin, Weon-Ho; Bulliard, Xavier; Park, Jong Hwan; Kim, Seyun; Chung, Jae Gwan; Kim, Yongsu; Heo, Sung; Kim, Seong Heon

2016-08-26

A novel, direct method for the characterization of the energy level alignments at bulk-heterojunction (BHJ)/electrode interfaces on the basis of electronic spectroscopy measurements is proposed. The home-made in situ photoemission system is used to perform x-ray/ultraviolet photoemission spectroscopy (XPS/UPS), reflection electron energy loss spectroscopy (REELS) and inverse photoemission spectroscopy of organic-semiconductors (OSCs) deposited onto a Au substrate. Through this analysis system, we are able to obtain the electronic structures of a boron subphthalocyanine chloride:fullerene (SubPC:C60) BHJ and those of the separate OSC/electrode structures (SubPC/Au and C60/Au). Morphology and chemical composition analyses confirm that the original SubPC and C60 electronic structures remain unchanged in the electrodes prepared. Using this technique, we ascertain that the position and area of the nearest peak to the Fermi energy (EF = 0 eV) in the UPS (REELS) spectra of SubPC:C60 BHJ provide information on the highest occupied molecular orbital level (optical band gap) and combination ratio of the materials, respectively. Thus, extracting the adjusted spectrum from the corresponding SubPC:C60 BHJ UPS (REELS) spectrum reveals its electronic structure, equivalent to that of the C60 materials. This novel analytical approach allows complete energy-level determination for each combination ratio by separating its electronic structure information from the BHJ spectrum.

spectroscopy

African Journals Online (AJOL)

Aghomotsegin

2015-10-14

Oct 14, 2015 ... characterized by using phenotypic, API and Fourier transform infrared (FTIR) spectroscopy methods. One hundred and fifty-seven (157) strains were isolated from 13 cheese samples, and identification test was performed for 83 strains. At the end of the study, a total of 22 Lactococcus sp., 36 Enterecoccus ...

Near-Infrared Spatially Resolved Spectroscopy for Tablet Quality Determination.

Science.gov (United States)

Igne, Benoît; Talwar, Sameer; Feng, Hanzhou; Drennen, James K; Anderson, Carl A

2015-12-01

Near-infrared (NIR) spectroscopy has become a well-established tool for the characterization of solid oral dosage forms manufacturing processes and finished products. In this work, the utility of a traditional single-point NIR measurement was compared with that of a spatially resolved spectroscopic (SRS) measurement for the determination of tablet assay. Experimental designs were used to create samples that allowed for calibration models to be developed and tested on both instruments. Samples possessing a poor distribution of ingredients (highly heterogeneous) were prepared by under-blending constituents prior to compaction to compare the analytical capabilities of the two NIR methods. The results indicate that SRS can provide spatial information that is usually obtainable only through imaging experiments for the determination of local heterogeneity and detection of abnormal tablets that would not be detected with single-point spectroscopy, thus complementing traditional NIR measurement systems for in-line, and in real-time tablet analysis. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Single-step biosynthesis and characterization of silver nanoparticles using Zornia diphylla leaves: A potent eco-friendly tool against malaria and arbovirus vectors.

Science.gov (United States)

Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan; Hoti, S L; Khater, Hanem F; Benelli, Giovanni

2016-08-01

Mosquitoes (Diptera: Culicidae) are vectors of important pathogens and parasites, including malaria, dengue, chikungunya, Japanese encephalitis, lymphatic filariasis and Zika virus. The application of synthetic insecticides causes development of resistance, biological magnification of toxic substances through the food chain, and adverse effects on the environment and human health. In this scenario, eco-friendly control tools of mosquito vectors are a priority. Here single-step fabrication of silver nanoparticles (AgNP) using a cheap aqueous leaf extract of Zornia diphylla as reducing and capping agent pf Ag(+) ions has been carried out. Biosynthesized AgNP were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX) and X-ray diffraction analysis (XRD). The acute toxicity of Z. diphylla leaf extract and biosynthesized AgNP was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Both the Z. diphylla leaf extract and Ag NP showed dose dependent larvicidal effect against all tested mosquito species. Compared to the leaf aqueous extract, biosynthesized Ag NP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 values of 12.53, 13.42 and 14.61μg/ml, respectively. Biosynthesized Ag NP were found safer to non-target organisms Chironomus circumdatus, Anisops bouvieri and Gambusia affinis, with the respective LC50 values ranging from 613.11 to 6903.93μg/ml, if compared to target mosquitoes. Overall, our results highlight that Z. diphylla-fabricated Ag NP are a promising and eco-friendly tool against larval populations of mosquito vectors of medical and veterinary importance, with negligible toxicity against other non-target organisms. Copyright © 2016 Elsevier B

Anisotropy in Bone Demineralization Revealed by Polarized Far-IR Spectroscopy

Directory of Open Access Journals (Sweden)

Roman Schuetz

2015-04-01

Full Text Available Bone material is composed of an organic matrix of collagen fibers and apatite nanoparticles. Previously, vibrational spectroscopy techniques such as infrared (IR and Raman spectroscopy have proved to be particularly useful for characterizing the two constituent organic and inorganic phases of bone. In this work, we tested the potential use of high intensity synchrotron-based far-IR radiation (50–500 cm−1 to gain new insights into structure and chemical composition of bovine fibrolamellar bone. The results from our study can be summarized in the following four points: (I compared to far-IR spectra obtained from synthetic hydroxyapatite powder, those from fibrolamellar bone showed similar peak positions, but very different peak widths; (II during stepwise demineralization of the bone samples, there was no significant change neither to far-IR peak width nor position, demonstrating that mineral dissolution occurred in a uniform manner; (III application of external loading on fully demineralized bone had no significant effect on the obtained spectra, while dehydration of samples resulted in clear differences. (IV using linear dichroism, we showed that the anisotropic structure of fibrolamellar bone is also reflected in anisotropic far-IR absorbance properties of both the organic and inorganic phases. Far-IR spectroscopy thus provides a novel way to functionally characterize bone structure and chemistry, and with further technological improvements, has the potential to become a useful clinical diagnostic tool to better assess quality of collagen-based tissues.

Characterization of organic thin films

CERN Document Server

Ulman, Abraham; Evans, Charles A

2009-01-01

Thin films based upon organic materials are at the heart of much of the revolution in modern technology, from advanced electronics, to optics to sensors to biomedical engineering. This volume in the Materials Characterization series introduces the major common types of analysis used in characterizing of thin films and the various appropriate characterization technologies for each. Materials such as Langmuir-Blodgett films and self-assembled monolayers are first introduced, followed by analysis of surface properties and the various characterization technologies used for such. Readers will find detailed information on: -Various spectroscopic approaches to characterization of organic thin films, including infrared spectroscopy and Raman spectroscopy -X-Ray diffraction techniques, High Resolution EELS studies, and X-Ray Photoelectron Spectroscopy -Concise Summaries of major characterization technologies for organic thin films, including Auger Electron Spectroscopy, Dynamic Secondary Ion Mass Spectrometry, and Tra...

Characterization of functional LB films using electron spin resonance spectroscopy

International Nuclear Information System (INIS)

Kuroda, Shin-ichi

1995-01-01

The role of ESR spectroscopy in the characterization of functional LB films is discussed. Unpaired electrons in LB films are associated with isolated radical molecules produced by charge transfer, paramagnetic metallic ions such as Cu 2+ , strongly interacting spins in the mixed valence states in charge-transfer salts, and so on. These spins often manifest the functions of materials. They can also act as microscopic probes in the ESR analysis devoted for the elucidation of characteristic properties of LB films. In structural studies, ESR is of particular importance in the analysis of molecular orientation of LB films. ESR can unambiguously determine the orientation of molecules through g-value anisotropy: different g value, different resonance field. Two types of new control methods of molecular orientation in LB films originated from the ESR analysis: study of in-plane orientation in dye LB films which led to the discovery of flow-orientation effect, and observation of drastic change of orientation of Cu-porphyrin in LB films using the trigger molecule, n-hexatriacontane. In the studies of electronic properties, hyperfine interactions between electron and nuclear spins provide information about molecular orbitals and local structures. Stable isotopes have been successfully applied to the stable radicals in merocyanine LB films to identify hyperfine couplings. In conducting LB films composed of charge-transfer salts, quasi-one-dimensional antiferromagnetism in semiconducting films and spin resonance of conduction electrons in metallic films are observed. Results provide microscopic evidence for the development of columnar structures of constituent molecules. Development of new functional LB films may provide more cases where ESR spectroscopy will clarify the nature of such films. (author)

A computational tool to characterize particle tracking measurements in optical tweezers

International Nuclear Information System (INIS)

Taylor, Michael A; Bowen, Warwick P

2013-01-01

Here, we present a computational tool for optical tweezers which calculates the particle tracking signal measured with a quadrant detector and the shot-noise limit to position resolution. The tool is a piece of Matlab code which functions within the freely available Optical Tweezers Toolbox. It allows the measurements performed in most optical tweezer experiments to be theoretically characterized in a fast and easy manner. The code supports particles with arbitrary size, any optical fields and any combination of objective and condenser, and performs a full vector calculation of the relevant fields. Example calculations are presented which show the tracking signals for different particles, and the shot-noise limit to position sensitivity as a function of the effective condenser NA. (paper)

Tools for LWR spent fuel characterization: Assembly classes and fuel designs

International Nuclear Information System (INIS)

Moore, R.S.; Notz, K.J.

1991-01-01

The Characteristics Data Base (CDB) is sponsored by the DOE's Office of Civilian Radioactive Waste Management (OCRWM). The CDB provides a single, comprehensive source of data pertaining to radioactive wastes that will or may require geologic disposal, including detailed data describing the physical, quantitative, and radiological characteristics of light-water reactor (LWR) spent fuel. In developing the CDB, tools for the classification of fuel assembly types have been developed. The assembly class scheme is particularly useful for size- and handling-based describes these tools and presents results of their applications in the areas of fuel assembly type identification, characterization of projected discharges, cask accommodation analyses, and defective fuel analyses. Suggestions for additional applications are also made. 7 refs., 1 fig., 2 tabs

Characterization of polymer surface structure and surface mechanical behaviour by sum frequency generation surface vibrational spectroscopy and atomic force microscopy

International Nuclear Information System (INIS)

Opdahl, Aric; Koffas, Telly S; Amitay-Sadovsky, Ella; Kim, Joonyeong; Somorjai, Gabor A

2004-01-01

Sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM) have been used to study polymer surface structure and surface mechanical behaviour, specifically to study the relationships between the surface properties of polymers and their bulk compositions and the environment to which the polymer is exposed. The combination of SFG surface vibrational spectroscopy and AFM has been used to study surface segregation behaviour of polyolefin blends at the polymer/air and polymer/solid interfaces. SFG surface vibrational spectroscopy and AFM experiments have also been performed to characterize the properties of polymer/liquid and polymer/polymer interfaces, focusing on hydrogel materials. A method was developed to study the surface properties of hydrogel contact lens materials at various hydration conditions. Finally, the effect of mechanical stretching on the surface composition and surface mechanical behaviour of phase-separated polyurethanes, used in biomedical implant devices, has been studied by both SFG surface vibrational spectroscopy and AFM. (topical review)

Characterizing free volumes and layer structures in polymeric membranes using slow positron annihilation spectroscopy

International Nuclear Information System (INIS)

Jean, Y C; Chen Hongmin; Awad, Somia; Zhang Sui; Chen Hangzheng; Lau, Cher Hon; Wang Huan; Li Fuyun; Chung, Tai-Shung; Lee, L James; Huang, James

2011-01-01

Positron annihilation spectroscopy coupled with a newly built slow positron beam at National University of Singapore has been used to study the free volume, pore, and depth profile (0 - 10 μm) in cellulose acetate polymeric membrane at the bottom and top sides of membranes for ionic separation in water purification applications. The S and R parameters from Doppler broadening energy of annihilation radiation representing free volumes (0.1-1 nm size) and pores (>1 nm-μm) as a function of depth have been analyzed into multilayers, i.e. skin dense, transition, and porous layers, respectively. The top side of membrane has large free volumes and pores and the bottom side has a skin dense layer, which plays a key role in membrane performance. Positron annihilation lifetime results provide additional information about free-volume size and distribution at the atomic and molecular scale in polymeric membrane systems. Doppler broadening energy and lifetime spectroscopies coupled with a variable mono-energy slow positron beam are sensitive and novel techniques for characterization of polymeric membrane in separation applications.

Characterization of pigment/binder - systems in arts via FTIR and UV/Vis/NIR - spectroscopy with special consideration of nondestructive methods

International Nuclear Information System (INIS)

Vetter, W.A.

2014-01-01

The main focus of this doctoral thesis is on the non-destructive analysis of art objects by using compound specific reflection-UV/Vis/NIR and reflection-FTIR spectroscopy. Based on commercially available instruments, measuring systems have been designed and built to meet the specific requirements of material analysis in the field of art. These systems have been utilized to analyse different types of art objects (watercolour paintings, easel paintings, contemporary graphic art objects) in order to identify the materials used by the artists. Furthermore, two new procedures are presented which allow to build up adequate reference databases from only minimal sample amounts of original watercolour materials of the 19th century. This is a crucial point as both methods require references for the identification of the materials. The results obtained demonstrate that UV/Vis/NIR and FTIR spectroscopy in reflection mode enable the non-destructive identification of a variety of both, organic and inorganic materials, particularly in combination with element specific XRF (X-ray fluorescence analysis) and thus are valuable tools for the analysis of cultural heritage objects. Furthermore, the results have shown that a comparison of the complementary methods strongly facilitated the evaluation of spectra obtained by the particular analytical techniques and hence reliable results could be obtained in many cases. As expected, several frequently used pigments e.g. carbon based blacks, earth pigments and lake pigments could not be identified unambiguously due to methodical limitations. Therefore, the use of additional complementary methods such as Raman spectroscopy and X-ray diffraction (XRD) would be highly desirable. Except a few examples, the characteristics of the radiation used for the investigations did not allow to draw conclusions about the distribution of materials in multilayer structures. For this reason, it still remains necessary to analyse cross-sections of samples for a

Advances in the in Vivo Raman Spectroscopy of Malignant Skin Tumors Using Portable Instrumentation

Directory of Open Access Journals (Sweden)

Nikolaos Kourkoumelis

2015-06-01

Full Text Available Raman spectroscopy has emerged as a promising tool for real-time clinical diagnosis of malignant skin tumors offering a number of potential advantages: it is non-intrusive, it requires no sample preparation, and it features high chemical specificity with minimal water interference. However, in vivo tissue evaluation and accurate histopathological classification remain a challenging task for the successful transition from laboratory prototypes to clinical devices. In the literature, there are numerous reports on the applications of Raman spectroscopy to biomedical research and cancer diagnostics. Nevertheless, cases where real-time, portable instrumentations have been employed for the in vivo evaluation of skin lesions are scarce, despite their advantages in use as medical devices in the clinical setting. This paper reviews the advances in real-time Raman spectroscopy for the in vivo characterization of common skin lesions. The translational momentum of Raman spectroscopy towards the clinical practice is revealed by (i assembling the technical specifications of portable systems and (ii analyzing the spectral characteristics of in vivo measurements.

Development and characterization of AlCrN coated Si3N4 ceramic cutting tool

International Nuclear Information System (INIS)

Souza, J.V.C.; Nono, M.C.A.; Machado, J.P.B.; Silva, O.M.M.; Sa, F.C.L.

2010-01-01

Ceramic cutting tools are showing a growing market perspective in terms of application on machining operations due to their high hardness, wear resistance, and machining without a cutting fluid, therefore are good candidates for cast iron and Nickel superalloys machining. The objective of the present paper was the development of Si 3 N 4 based ceramic cutting insert, characterization of its physical and mechanical properties, and subsequent coating with AlCrN using a PVD method. The characterization of the coating was made using an optical profiler, XRD, AFM and microhardness tester. The results showed that the tool presented a fracture toughness of 6,43 MPa.m 1/2 and hardness of 16 GPa. The hardness reached 31 GPa after coating. The machining tests showed an improvement on work piece roughness when machining with coated insert, in comparison with the uncoated cutting tool. Probably this fact is related to hardness, roughness and topography of AlCrN. (author)

Microstructural characterization of cermet-steel interface in rock drilling tool

International Nuclear Information System (INIS)

Ybarra, L.A.C.; Molisani, A.L.; Yoshimura, H.N.

2010-01-01

Rock drilling tools basically present a WC cermet bonded to a steel shank. The interface cermet-steel plays fundamental role during drilling operation, since the fracture of this interface is the main failure mode of the tools. In this work, the microstructure of this interface in crown samples (type A), prepared in an industrial like process, was evaluated. In this process, a WC-containing powder was infiltrated with a copper alloy at 1100 deg C in a graphite mold previously mounted with a 1020 steel tube. The powder was characterized by XRD analysis and the cross-section microstructure of cermet-steel was analyzed using SEM-EDS. It was observed that Ni and small amount of Cu from cermet matrix diffused into the superficial region of the steel, and the Cu alloy dissolved and penetrated along the steel grain boundaries, resulting in good metallurgical bonding of the interface.(author)

Selecting analytical tools for characterization of polymersomes in aqueous solution

DEFF Research Database (Denmark)

Habel, Joachim Erich Otto; Ogbonna, Anayo; Larsen, Nanna

2015-01-01

/purification. Of the analytical methods tested, Cryo-transmission electron microscopy and atomic force microscopy (AFM) turned out to be advantageous for polymersomes with smaller diameter than 200 nm, whereas confocal microscopy is ideal for diameters >400 nm. Polymersomes in the intermediate diameter range can be characterized...... using freeze fracture Cryo-scanning electron microscopy (FF-Cryo-SEM) and nanoparticle tracking analysis (NTA). Small angle X-ray scattering (SAXS) provides reliable data on bilayer thickness and internal structure, Cryo-TEM on multilamellarity. Taken together, these tools are valuable...

High resolution hard X-ray photoemission using synchrotron radiation as an essential tool for characterization of thin solid films

International Nuclear Information System (INIS)

Kim, J.J.; Ikenaga, E.; Kobata, M.; Takeuchi, A.; Awaji, M.; Makino, H.; Chen, P.P.; Yamamoto, A.; Matsuoka, T.; Miwa, D.; Nishino, Y.; Yamamoto, T.; Yao, T.; Kobayashi, K.

2006-01-01

Recently, we have shown that hard X-ray photoemission spectroscopy using undulator X-rays at SPring-8 is quite feasible with both high resolution and high throughput. Here we report an application of hard X-ray photoemission spectroscopy to the characterization of electronic and chemical states of thin solid films, for which conventional PES is not applicable. As a typical example, we focus on the problem of the scatter in the reported band-gap values for InN. We show that oxygen incorporation into the InN film strongly modifies the valence and plays a crucial role in the band gap problem. The present results demonstrate the powerful applicability of high resolution photoemission spectroscopy with hard X-rays from a synchrotron source

Characterizing the Energetics of the Youngest Protostars: FIFI-LS Spectroscopy of Herschel-Identified Extreme Class 0 objects in Orion

Science.gov (United States)

Megeath, S.

2014-10-01

We propose FIFI-LS spectroscopy observations toward 3 of the youngest known Herschel- detected Class 0 protostars in the Orion molecular clouds. Characterization of the far-IR spectrum toward these PACS Bright Red Sources (PBRS) is imperative: this is the only observational means to characterize the complete energetics of the outflow in the earliest stages of the star formation process. We have already obtained Herschel-PACS spectroscopy for 8/14 PBRS; for these, the CO rotation temperatures are systematically lower than the larger samples of 'more typical' protostars observed. Furthermore, all of the Herschel-detected PBRS also have CARMA CO (J=1-0) outflow maps, enabling us to identify tentative trends between the detection and morphology (compact or extended) of the CO outflow and the presence or lack of far-infrared emission lines. Moreover, we only convincingly detect [OI] emission toward the source with the brightest outflow emission; thus, [OI] may not be universally present in protostellar outflows. However, due to the small-numbers with PACS spectroscopy, it is unclear if these trends are real and the three proposed PBRS have outflow maps of varying morphologies, but no far-infrared spectra. The results from this program will provide a firm observational footing for the presence or lack of such trends and will strengthen the connection of the far-IR emission lines to the outflow.

A novel analytical method for pharmaceutical polymorphs by terahertz spectroscopy and the optimization of crystal form at the discovery stage.

Science.gov (United States)

Ikeda, Yukihiro; Ishihara, Yoko; Moriwaki, Toshiya; Kato, Eiji; Terada, Katsuhide

2010-01-01

A novel analytical method for the determination of pharmaceutical polymorphs was developed using terahertz spectroscopy. It was found out that each polymorph of a substance showed a specific terahertz absorption spectrum. In particular, analysis of the second derivative spectrum was enormously beneficial in the discrimination of closely related polymorphs that were difficult to discern by powder X-ray diffractometry. Crystal forms that were obtained by crystallization from various solvents and stored under various conditions were specifically characterized by the second derivative of each terahertz spectrum. Fractional polymorphic transformation for substances stored under stressed conditions was also identified by terahertz spectroscopy during solid-state stability test, but could not be detected by powder X-ray diffractometry. Since polymorphs could be characterized clearly by terahertz spectroscopy, further physicochemical studies could be conducted in a timely manner. The development form of compound examined was determined by the results of comprehensive physicochemical studies that included thermodynamic relationships, as well as chemical and physicochemical stability. In conclusion, terahertz spectroscopy, which has unique power in the elucidation of molecular interaction within a crystal lattice, can play more important role in physicochemical research. Terahertz spectroscopy has a great potential as a tool for polymorphic determination, particularly since the second derivative of the terahertz spectrum possesses high sensitivity for pharmaceutical polymorphs.

Application of far-infrared spectroscopy to the structural identification of protein materials.

Science.gov (United States)

Han, Yanchen; Ling, Shengjie; Qi, Zeming; Shao, Zhengzhong; Chen, Xin

2018-05-03

Although far-infrared (IR) spectroscopy has been shown to be a powerful tool to determine peptide structure and to detect structural transitions in peptides, it has been overlooked in the characterization of proteins. Herein, we used far-IR spectroscopy to monitor the structure of four abundant non-bioactive proteins, namely, soybean protein isolate (SPI), pea protein isolate (PPI) and two types of silk fibroins (SFs), domestic Bombyx mori and wild Antheraea pernyi. The two globular proteins SPI and PPI result in broad and weak far-IR bands (between 50 and 700 cm-1), in agreement with those of some other bioactive globular proteins previously studied (lysozyme, myoglobin, hemoglobin, etc.) that generally only have random amino acid sequences. Interestingly, the two SFs, which are characterized by a structure composed of highly repetitive motifs, show several sharp far-IR characteristic absorption peaks. Moreover, some of these characteristic peaks (such as the peaks at 260 and 428 cm-1 in B. mori, and the peaks at 245 and 448 cm-1 in A. pernyi) are sensitive to conformational changes; hence, they can be directly used to monitor conformational transitions in SFs. Furthermore, since SF absorption bands clearly differ from those of globular proteins and different SFs even show distinct adsorption bands, far-IR spectroscopy can be applied to distinguish and determine the specific SF component within protein blends.

Characterization of Zircaloy-4 oxide layers by impedance spectroscopy

International Nuclear Information System (INIS)

Barberis, P.

1999-01-01

Two Zircaloy-4 type alloys with different tin contents (0.5 and 1.2 wt%) have been oxidized in autoclave (400 C in steam) for several durations (1-140 days). The film has been characterized by electrochemical impedance spectroscopy (EIS). Several soaking times have been investigated (up to 40 days). The Cole-Cole representation has been used to display and study the data. A simple electrical model has been derived from the observed spectra: the electrical circuit includes two RC loops in series, whose capacitances are frequency dispersed. It is thoroughly related to the layer structure. It has been shown that even before the kinetic transition, the film is constituted of three parts: an inner layer which is compact, an outer layer subdivided in an external region immediately soaked by the electrolyte, and an internal one in which electrolyte diffusion processes can take place. The kinetic transition is interpreted in terms of an abrupt 'compacity' change, both layers degrading at this point. The alloy with high tin content exhibits higher dispersive properties of the oxide layer formed on it, in correlation with its faster oxidation kinetics. (orig.)

Resonance Raman spectroscopy in one-dimensional carbon materials

Directory of Open Access Journals (Sweden)

Dresselhaus Mildred S.

2006-01-01

Full Text Available Brazil has played an important role in the development and use of resonance Raman spectroscopy as a powerful characterization tool for materials science. Here we present a short history of Raman scattering research in Brazil, highlighting the important contributions to the field coming from Brazilian researchers in the past. Next we discuss recent and important contributions where Brazil has become a worldwide leader, that is on the physics of quasi-one dimensional carbon nanotubes. We conclude this article by presenting results from a very recent resonance Raman study of exciting new materials, that are strictly one-dimensional carbon chains formed by the heat treatment of very pure double-wall carbon nanotube samples.

Autofluorescence and diffuse reflectance patterns in cervical spectroscopy

Science.gov (United States)

Marin, Nena Maribel

Fluorescence and diffuse reflectance spectroscopy are two new optical technologies, which have shown promise to aid in the real time, non-invasive identification of cancers and precancers. Spectral patterns carry a fingerprint of scattering, absorption and fluorescence properties in tissue. Scattering, absorption and fluorescence in tissue are directly affected by biological features that are diagnostically significant, such as nuclear size, micro-vessel density, volume fraction of collagen fibers, tissue oxygenation and cell metabolism. Thus, analysis of spectral patterns can unlock a wealth of information directly related with the onset and progression of disease. Data from a Phase II clinical trial to assess the technical efficacy of fluorescence and diffuse reflectance spectroscopy acquired from 850 women at three clinical locations with two research grade optical devices is calibrated and analyzed. Tools to process and standardize spectra so that data from multiple spectrometers can be combined and analyzed are presented. Methodologies for calibration and quality assurance of optical systems are established to simplify design issues and ensure validity of data for future clinical trials. Empirically based algorithms, using multivariate statistical approaches are applied to spectra and evaluated as a clinical diagnostic tool. Physically based algorithms, using mathematical models of light propagation in tissue are presented. The presented mathematical model combines a diffusion theory in P3 approximation reflectance model and a 2-layer fluorescence model using exponential attenuation and diffusion theory. The resulting adjoint fluorescence and reflectance model extracts twelve optical properties characterizing fluorescence efficiency of cervical epithelium and stroma fluorophores, stromal hemoglobin and collagen absorption, oxygen saturation, and stromal scattering strength and shape. Validations with Monte Carlo simulations show that adjoint model extracted

Characterization of gold nanoparticle films: Rutherford backscattering spectroscopy, scanning electron microscopy with image analysis, and atomic force microscopy

Directory of Open Access Journals (Sweden)

Pia C. Lansåker

2014-10-01

Full Text Available Gold nanoparticle films are of interest in several branches of science and technology, and accurate sample characterization is needed but technically demanding. We prepared such films by DC magnetron sputtering and recorded their mass thickness by Rutherford backscattering spectroscopy. The geometric thickness dg—from the substrate to the tops of the nanoparticles—was obtained by scanning electron microscopy (SEM combined with image analysis as well as by atomic force microscopy (AFM. The various techniques yielded an internally consistent characterization of the films. In particular, very similar results for dg were obtained by SEM with image analysis and by AFM.

Raman spectroscopy provides a powerful diagnostic tool for accurate determination of albumin glycation.

Science.gov (United States)

Dingari, Narahara Chari; Horowitz, Gary L; Kang, Jeon Woong; Dasari, Ramachandra R; Barman, Ishan

2012-01-01

We present the first demonstration of glycated albumin detection and quantification using Raman spectroscopy without the addition of reagents. Glycated albumin is an important marker for monitoring the long-term glycemic history of diabetics, especially as its concentrations, in contrast to glycated hemoglobin levels, are unaffected by changes in erythrocyte life times. Clinically, glycated albumin concentrations show a strong correlation with the development of serious diabetes complications including nephropathy and retinopathy. In this article, we propose and evaluate the efficacy of Raman spectroscopy for determination of this important analyte. By utilizing the pre-concentration obtained through drop-coating deposition, we show that glycation of albumin leads to subtle, but consistent, changes in vibrational features, which with the help of multivariate classification techniques can be used to discriminate glycated albumin from the unglycated variant with 100% accuracy. Moreover, we demonstrate that the calibration model developed on the glycated albumin spectral dataset shows high predictive power, even at substantially lower concentrations than those typically encountered in clinical practice. In fact, the limit of detection for glycated albumin measurements is calculated to be approximately four times lower than its minimum physiological concentration. Importantly, in relation to the existing detection methods for glycated albumin, the proposed method is also completely reagent-free, requires barely any sample preparation and has the potential for simultaneous determination of glycated hemoglobin levels as well. Given these key advantages, we believe that the proposed approach can provide a uniquely powerful tool for quantification of glycation status of proteins in biopharmaceutical development as well as for glycemic marker determination in routine clinical diagnostics in the future.

Raman Spectroscopy Provides a Powerful Diagnostic Tool for Accurate Determination of Albumin Glycation

Science.gov (United States)

Dingari, Narahara Chari; Horowitz, Gary L.; Kang, Jeon Woong; Dasari, Ramachandra R.; Barman, Ishan

2012-01-01

We present the first demonstration of glycated albumin detection and quantification using Raman spectroscopy without the addition of reagents. Glycated albumin is an important marker for monitoring the long-term glycemic history of diabetics, especially as its concentrations, in contrast to glycated hemoglobin levels, are unaffected by changes in erythrocyte life times. Clinically, glycated albumin concentrations show a strong correlation with the development of serious diabetes complications including nephropathy and retinopathy. In this article, we propose and evaluate the efficacy of Raman spectroscopy for determination of this important analyte. By utilizing the pre-concentration obtained through drop-coating deposition, we show that glycation of albumin leads to subtle, but consistent, changes in vibrational features, which with the help of multivariate classification techniques can be used to discriminate glycated albumin from the unglycated variant with 100% accuracy. Moreover, we demonstrate that the calibration model developed on the glycated albumin spectral dataset shows high predictive power, even at substantially lower concentrations than those typically encountered in clinical practice. In fact, the limit of detection for glycated albumin measurements is calculated to be approximately four times lower than its minimum physiological concentration. Importantly, in relation to the existing detection methods for glycated albumin, the proposed method is also completely reagent-free, requires barely any sample preparation and has the potential for simultaneous determination of glycated hemoglobin levels as well. Given these key advantages, we believe that the proposed approach can provide a uniquely powerful tool for quantification of glycation status of proteins in biopharmaceutical development as well as for glycemic marker determination in routine clinical diagnostics in the future. PMID:22393405

Intermediate Experimental Vehicle, ESA Program IXV ATDB Tool and Aerothermodynamic Characterization

Science.gov (United States)

Mareschi, Vincenzo; Ferrarella, Daniela; Zaccagnino, Elio; Tribot, Jean-Pierre; Vallee, Jean-Jacques; Haya-Ramos, Rodrigo; Rufolo, Giuseppe; Mancuso, Salvatore

2011-05-01

In the complex domain of the space technologies and among the different applications available in Europe, a great interest has been placed since several years in the development of re-entry technologies. Among the different achievements obtained in that field it is to be recalled the experience of the Atmospheric Re-entry Vehicle flight in 1998 and a certain number of important investments per-formed at Agency and national levels like Hermes, MSTP, Festip, X-38, FLPP, TRP, GSTP, HSTS, AREV, Pre-X. IXV (Intermediate eXperimental V ehicle) builds on these past experiences and studies and it is conceived to be the next technological step forward with respect to ARD With respect to previous European ballistic or quasi- ballistic demonstrators, IXV will have an increased in- flight manoeuvrability and the planned mission will allow verifying the performances of the required technologies against a wider re-entry corridor. This will imply from the pure technological aspect to increase the level of engagement on critical technologies and disciplines like aerodynamics/aerothermodynamics, guidance, navigation, control, thermal protection materials and in flight measurements. In order to support the TPS design and the other sub- systems, an AeroThermodynamicDataBase Tool has been developed by Dassault Aviation and integrated by Thales Alenia Space with the Functional Engineering Simulator (used for GNC performances evaluation) in order to characterize the aerothermodynamic behaviour of the vehicle. This paper will describe: - The methodology used to develop the ATDB tool, based on the processing of CFD computations and WTT campaigns results. - The utilization of the ATDB tool, by means of its integration into the System process. - The methodology used for the aerothermal characterization of IXV.

Optical Spectroscopy

DEFF Research Database (Denmark)

Thyrhaug, Erling

The work presented in this thesis is broadly concerned with how complexation reactions and molecular motion can be characterized with the standard techniques in optical spectroscopy. The thesis aims to show a relatively broad range of methods for probing physico-chemical properties in fluorophore...... information about chemical equilibria, kinetics and molecular motion by monitoring changes in optical properties of the system. The five presented research projects are largely unrelated to each other both in aim and in what property is probed, however they are all connected in that they are fluorophore...... reactions by optical spectroscopy. In project 1 simple steady-state absorption and fluorescence spectroscopy is used to determine the stoichiometries and equilibrium constants in the inclusion complex formation between cyclodextrins and derivatives of the water-insoluble oligo(phenylene vinylene) in aqueous...

Molecular studies by electron spectroscopy

International Nuclear Information System (INIS)

Hansteen, J.M.

1977-01-01

Experience gained in experimental nuclear physics has played a large role in the development of electron spectroscopy as a powerful tool for studying chemical systems. The use of ESCA (Electron Spectroscopy for Chemical Analysis) for the mapping of molecular properties connected with inner as well as outer electron shells is reviewed, mainly from a phenomological point of view. Molecular Auger electron spectroscopy is described as a means of gaining information on details in molecular structure, simultaneously being extensively applied for surface studies. Future highly promising research areas for molecular electron spectroscopy are suggested to be (e,2e) processes as well as continued exploitation of synchrotron radiation from high energy nuclear devices. (Auth.)

Extreme Spectroscopy: In situ nuclear materials behavior from optical data

Energy Technology Data Exchange (ETDEWEB)

Guimbretiere, G.; Canizares, A.; Raimboux, N.; Omnee, R.; Duval, F.; Ammar, M.R.; Simon, P. [CNRS - UPR3079 CEMHTI, Universite d' Orleans, 45071Orleans cedex 2 (France); Desgranges, L.; Mohun, R. [CEA, DEN, DEC, F-13108 Saint-Paul-Lez-Durance (France); Jegou, C.; Magnin, M. [CEA/DTCD/SECM/LMPA, Marcoule 30207 Bagnols Sur Ceze (France); Clavier, N.; Dacheux, N. [ICSM-UMR5257 CEA/CNRS/UM2/ENSCM, Marcoule, BP17171, 30207 Bagnols sur Ceze (France)

2015-07-01

In the nuclear industry, materials are regularly exposed to high temperature or/and irradiation and a better knowledge and understanding of their behavior under such extreme conditions is a key-point for improvements and further developments. Nowadays, Raman spectroscopy begins to be well known as a promising technique in the post mortem and remote characterization of nuclear materials exposed to extreme conditions. On this topic, at ANIMMA 2013 conference, we have presented some results about its implementation in the study of model or real nuclear fuel. However, the strength of Raman spectroscopy as in situ characterization tool is mainly its ability to be implemented remotely through optical fibers. Aware of this, implementation of other optical techniques can be considered in order to gain information not only on the structural dynamics of materials but also on the electronic charge carrier populations. In this paper, we propose to present our last advances in Raman characterization of nuclear materials and enlarge to the in situ use of complementary optical spectroscopies. Emphasis will be made on the information that can be gained to the behavior of the model fuel depleted UO{sub 2} under extreme conditions of high temperature and ionic irradiation: - In Situ Raman identification of the radiolysis alteration products of UO{sub 2} in contact with water under ionic irradiation. - In Situ Raman recording of the damaged dynamic of UO{sub 2} under inert atmosphere. - In Situ Raman and photo-luminescence study of virgin and damaged UO2 at high temperature. - In Situ study of electronic charge carriers' behavior in U{sub x}Th{sub 1-x}O{sub 2} solid solutions by mean of Iono- and Thermo- luminescence under and post- ionic irradiation. (authors)

Characterization and correction of the false-discovery rates in resting state connectivity using functional near-infrared spectroscopy

Science.gov (United States)

Santosa, Hendrik; Aarabi, Ardalan; Perlman, Susan B.; Huppert, Theodore J.

2017-05-01

Functional near-infrared spectroscopy (fNIRS) is a noninvasive neuroimaging technique that uses low levels of red to near-infrared light to measure changes in cerebral blood oxygenation. Spontaneous (resting state) functional connectivity (sFC) has become a critical tool for cognitive neuroscience for understanding task-independent neural networks, revealing pertinent details differentiating healthy from disordered brain function, and discovering fluctuations in the synchronization of interacting individuals during hyperscanning paradigms. Two of the main challenges to sFC-NIRS analysis are (i) the slow temporal structure of both systemic physiology and the response of blood vessels, which introduces false spurious correlations, and (ii) motion-related artifacts that result from movement of the fNIRS sensors on the participants' head and can introduce non-normal and heavy-tailed noise structures. In this work, we systematically examine the false-discovery rates of several time- and frequency-domain metrics of functional connectivity for characterizing sFC-NIRS. Specifically, we detail the modifications to the statistical models of these methods needed to avoid high levels of false-discovery related to these two sources of noise in fNIRS. We compare these analysis procedures using both simulated and experimental resting-state fNIRS data. Our proposed robust correlation method has better performance in terms of being more reliable to the noise outliers due to the motion artifacts.

Novel diamond-coated tools for dental drilling applications.

Science.gov (United States)

Jackson, M J; Sein, H; Ahmed, W; Woodwards, R

2007-01-01

The application of diamond coatings on cemented tungsten carbide (WC-Co) tools has been the subject of much attention in recent years in order to improve cutting performance and tool life in orthodontic applications. WC-Co tools containing 6% Co metal and 94% WC substrate with an average grain size of 1 - 3 microm were used in this study. In order to improve the adhesion between diamond and WC substrates it is necessary to etch cobalt from the surface and prepare it for subsequent diamond growth. Alternatively, a titanium nitride (TiN) interlayer can be used prior to diamond deposition. Hot filament chemical vapour deposition (HFCVD) with a modified vertical filament arrangement has been employed for the deposition of diamond films to TiN and etched WC substrates. Diamond film quality and purity has been characterized using scanning electron microscopy (SEM) and micro Raman spectroscopy. The performances of diamond-coated WC-Co tools, uncoated WC-Co tools, and diamond embedded (sintered) tools have been compared by drilling a series of holes into various materials such as human tooth, borosilicate glass, and acrylic tooth materials. Flank wear has been used to assess the wear rates of the tools when machining biomedical materials such as those described above. It is shown that using an interlayer such as TiN prior to diamond deposition provides the best surface preparation for producing dental tools.

The Optical Absorption Coefficient of Maize Grains Investigated by Photoacoustic Spectroscopy

Science.gov (United States)

Rodríguez-Páez, C. L.; Carballo-Carballo, A.; Rico-Molina, R.; Hernández-Aguilar, C.; Domínguez-Pacheco, A.; Cruz-Orea, A.; Moreno-Martínez, E.

2017-01-01

In the maize and tortilla industry, it is important to characterize the color of maize ( Zea mays L.) grain, as it is one of the attributes that directly affect the quality of the tortillas consumed by the population. For this reason, the availability of alternative techniques for assessing and improving the quality of grain is valued. Photoacoustic spectroscopy has proven to be a useful tool for characterizing maize grain. So, the objective of the present study was to determine the optical absorption coefficient β of the maize grain used to make tortillas from two regions of Mexico: (a) Valles Altos, 2012-2013 production cycle and (b) Guasave, Sinaloa, 2013-2014 production cycle. Traditional reflectance measurements, physical characteristics of the grain and nutrient content were also calculated. The experimental results show different characteristics for maize grains.

Surface metallurgy of cemented carbide tools

International Nuclear Information System (INIS)

Chopra, K.L.; Kashyap, S.C.; Rao, T.V.; Rajagopalan, S.; Srivastava, P.K.

1983-01-01

Transition metal carbides, owing to their high melting point, hardness and wear resistance, are potential candidates for specific application in rockets, nuclear engineering equipment and cutting tools. Tungsten carbide sintered with a binder (either cobalt metal or a mixture of Co + TiC and/or TaC(NbC)) is used for cutting tools. The surface metallurgy of several commercially available cemented carbide tools was studied by Auger electron spectroscopy and X-ray photoelectron spectroscopy techniques. The tool surfaces were contaminated by adsorbed oxygen up to a depth of nearly 0.3 μm causing deterioration of the mechanical properties of the tools. Studies of fractured samples indicated that the tool surfaces were prone to oxygen adsorption. The fracture path passes through the cobalt-rich regions. The ineffectiveness of a worn cutting tool is attributed to the presence of excessive iron from the steel workpiece and carbon and oxygen in the surface layers of the tool. The use of appropriate hard coatings on cemented carbide tools is suggested. (Auth.)

Moessbauer spectroscopy

International Nuclear Information System (INIS)

Gonser, U.

1975-01-01

This book is addressed to persons interested in learning about what has been done and what can be done with Moessbauer spectroscopy. In an introductory chapter the basic principle is explained and the general parameters governing Moessbauer spectroscopy are tabulated. For the following chapters various disciplines are chosen and the wide applicability of this measuring technique is demonstrated. The second chapter discusses a few representative examples of chemical interesting information being reflected by isomer shifts and quadrupole splittings, particularly with respect to bonding and structural properties. The third chapter deals with some applications of Moessbauer spectroscopy for characterizing magnetic compounds and its use for magnetic structure investigations, particularly by making use of polarized radiation. The fourth chapter describes the use of the Moessbauer spectroscopy for studying iron in biological molecules. As an example of recent applications to mineralogy and geology the results of the studies of lunar samples are reviewed in the fifth chapter. Finally, in the last chapter, work is described on the use of Moessbauer spectroscopy in physical metallurgy, particularly quantitative analyses which have enabled metallurgists to solve many old problems. (orig./FW) [de

Molecular ions, Rydberg spectroscopy and dynamics

International Nuclear Information System (INIS)

Jungen, Ch.

2015-01-01

Ion spectroscopy, Rydberg spectroscopy and molecular dynamics are closely related subjects. Multichannel quantum defect theory is a theoretical approach which draws on this close relationship and thereby becomes a powerful tool for the study of systems consisting of a positively charged molecular ion core interacting with an electron which may be loosely bound or freely scattering

Molecular ions, Rydberg spectroscopy and dynamics

Energy Technology Data Exchange (ETDEWEB)

Jungen, Ch. [Laboratoire Aimé Cotton, Université de Paris-Sud, 91405 Orsay (France)

2015-01-22

Ion spectroscopy, Rydberg spectroscopy and molecular dynamics are closely related subjects. Multichannel quantum defect theory is a theoretical approach which draws on this close relationship and thereby becomes a powerful tool for the study of systems consisting of a positively charged molecular ion core interacting with an electron which may be loosely bound or freely scattering.

Point defects in gallium arsenide characterized by positron annihilation spectroscopy and deep level transient spectroscopy

International Nuclear Information System (INIS)

Mih, R.; Gronsky, R.; Sterne, P.A.

1995-01-01

Positron annihilation lifetime spectroscopy (PALS) is a unique technique for detection of vacancy related defects in both as-grown and irradiated materials. The authors present a systematic study of vacancy defects in stoichiometrically controlled p-type Gallium Arsenide grown by the Hot-Wall Czochralski method. Microstructural information based on PALS, was correlated to crystallographic data and electrical measurements. Vacancies were detected and compared to electrical levels detected by deep level transient spectroscopy and stoichiometry based on crystallographic data

Infrared characterization of environmental samples by pulsed photothermal spectroscopy

International Nuclear Information System (INIS)

Seidel, W.; Foerstendorf, H.; Heise, K.H.; Nicolai, R.; Schamlott, A.; Ortega, J.M.; Glotin, F.; Prazeres, R.

2004-01-01

Low concentration of toxic radioactive metals in environmental samples often limits the interpretation of results of infrared studies investigating the interaction processes between the metal ions and environmental compartments. For the first time, we could show that photothermal infrared spectroscopy performed with a pulsed free electron laser can provide reliable infrared spectra throughout a distinct spectral range of interest. In this model investigation, we provide vibrational absorption spectra of a rare earth metal salt dissolved in a KBr matrix and a natural calcite sample obtained by photothermal beam deflection (PTBD) technique and FT-IR (Fourier-transform infrared) spectroscopy, respectively. General agreement was found between all spectra of the different recording techniques. Spectral deviations were observed with samples containing low concentration of the rare earth metal salt indicating a lower detection limit of the photothermal method as compared to conventional FT-IR spectroscopy. (authors)

Photoluminescence as a tool for characterizing point defects in semiconductors

Science.gov (United States)

Reshchikov, Michael

2012-02-01

Photoluminescence is one of the most powerful tools used to study optically-active point defects in semiconductors, especially in wide-bandgap materials. Gallium nitride (GaN) and zinc oxide (ZnO) have attracted considerable attention in the last two decades due to their prospects in optoelectronics applications, including blue and ultraviolet light-emitting devices. However, in spite of many years of extensive studies and a great number of publications on photoluminescence from GaN and ZnO, only a few defect-related luminescence bands are reliably identified. Among them are the Zn-related blue band in GaN, Cu-related green band and Li-related orange band in ZnO. Numerous suggestions for the identification of other luminescence bands, such as the yellow band in GaN, or green and yellow bands in ZnO, do not stand up under scrutiny. In these conditions, it is important to classify the defect-related luminescence bands and find their unique characteristics. In this presentation, we will review the origin of the major luminescence bands in GaN and ZnO. Through simulations of the temperature and excitation intensity dependences of photoluminescence and by employing phenomenological models we are able to obtain important characteristics of point defects such as carrier capture cross-sections for defects, concentrations of defects, and their charge states. These models are also used to find the absolute internal quantum efficiency of photoluminescence and obtain information about nonradiative defects. Results from photoluminescence measurements will be compared with results of the first-principle calculations, as well as with the experimental data obtained by other techniques such as positron annihilation spectroscopy, deep-level transient spectroscopy, and secondary ion mass spectrometry.

Solid NMR characterization of hydrogen solid storage matrices

International Nuclear Information System (INIS)

Pilette, M.A.; Charpentier, T.; Berthault, P.

2007-01-01

The aim of this work is to develop and validate characterization tools by NMR imagery and spectroscopy of the structure of materials for hydrogen storage, and of their evolution during load/unload cycles. The two main topics of this work are in one hand the analysis of the local structure of the materials and the understanding of their eventual modifications, and in another hand, the in-situ analysis of the distribution and diffusion of hydrogen inside the storage material. (O.M.)

SAXS Combined with UV-vis Spectroscopy and QELS: Accurate Characterization of Silver Sols Synthesized in Polymer Matrices.

Science.gov (United States)

Bulavin, Leonid; Kutsevol, Nataliya; Chumachenko, Vasyl; Soloviov, Dmytro; Kuklin, Alexander; Marynin, Andrii

2016-12-01

The present work demonstrates a validation of small-angle X-ray scattering (SAXS) combining with ultra violet and visible (UV-vis) spectroscopy and quasi-elastic light scattering (QELS) analysis for characterization of silver sols synthesized in polymer matrices. Polymer matrix internal structure and polymer chemical nature actually controlled the sol size characteristics. It was shown that for precise analysis of nanoparticle size distribution these techniques should be used simultaneously. All applied methods were in good agreement for the characterization of size distribution of small particles (less than 60 nm) in the sols. Some deviations of the theoretical curves from the experimental ones were observed. The most probable cause is that nanoparticles were not entirely spherical in form.

IR spectroscopy together with multivariate data analysis as a process analytical tool for in-line monitoring of crystallization process and solid-state analysis of crystalline product

DEFF Research Database (Denmark)

Pöllänen, Kati; Häkkinen, Antti; Reinikainen, Satu-Pia

2005-01-01

-ray powder diffraction (XRPD) as a reference technique. In order to fully utilize DRIFT, the application of multivariate techniques are needed, e.g., multivariate statistical process control (MSPC), principal component analysis (PCA) and partial least squares (PLS). The results demonstrate that multivariate...... Fourier transform infra red (ATR-FTIR) spectroscopy provides valuable information on process, which can be utilized for more controlled crystallization processes. Diffuse reflectance Fourier transform infra red (DRIFT-IR) is applied for polymorphic characterization of crystalline product using X......Crystalline product should exist in optimal polymorphic form. Robust and reliable method for polymorph characterization is of great importance. In this work, infra red (IR) spectroscopy is applied for monitoring of crystallization process in situ. The results show that attenuated total reflection...

Chlorococcalean microalgae Ankistrodesmus convolutes biodiesel characterization with Fourier transform-infrared spectroscopy and gas chromatography mass spectroscopy techniques

Directory of Open Access Journals (Sweden)

Swati SONAWANE

2015-12-01

Full Text Available The Chlorococcalean microalgae Ankistrodesmus convolutes was found in fresh water Godawari reservoir, Ahmednagar district of Maharashtra State, India. Microalgae are modern biomass for the production of liquid biofuel due to its high solar cultivation efficiency. The collection, harvesting and drying processes were play vital role in converting algal biomass into energy liquid fuel. The oil extraction was the important step for the biodiesel synthesis. The fatty acid methyl ester (FAME synthesis was carried through base catalyzed transesterification method. The product was analyzed by using the hyphened techniques like Fourier Transform-Infrared spectroscopy (FT-IR and Gas Chromatography Mass Spectroscopy (GCMS. FT-IR Spectroscopy was results the ester as functional group of obtained product while the Gas Chromatography Mass Spectroscopy was results the six type of fatty acid methyl ester with different concentration. Ankistrodesmus convolutes biodiesel consist of 46.5% saturated and 49.14% unsaturated FAME.

Characterization of the major nutritional components of Caryocar brasiliense fruit pulp by NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Miranda-Vilela, Ana Luisa; Grisolia, Cesar Koppe [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Ciencias Biologicas. Dept. de Genetica e Morfologia; Resck, Ines Sabioni; Mendonca, Marcio Antonio [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Quimica

2009-07-01

Pequi (Caryocar brasiliense Camb.), a typical fruit of Brazilian Cerrado, is well known in regional cookery and used in folk medicine to treat various illnesses. Mass spectrometry and chromatographic methods have identified the organic composition of pequi fruit pulp; however, NMR spectroscopy is used for the first time to characterize the nutritional components of organic and aqueous-ethanolic extracts. This spectroscopic technique determined the triacylglycerols in the pequi organic fraction, which is constituted mainly by oleate and palmitate esters, and detected the carbohydrate mixtures as the major components of aqueous and ethanolic fractions, respectively. In this study, presence of phenolic compounds was only evidenced in the ethanolic fraction. (author)

Characterization of the major nutritional components of Caryocar brasiliense fruit pulp by NMR spectroscopy

International Nuclear Information System (INIS)

Miranda-Vilela, Ana Luisa; Grisolia, Cesar Koppe; Resck, Ines Sabioni; Mendonca, Marcio Antonio

2009-01-01

Pequi (Caryocar brasiliense Camb.), a typical fruit of Brazilian Cerrado, is well known in regional cookery and used in folk medicine to treat various illnesses. Mass spectrometry and chromatographic methods have identified the organic composition of pequi fruit pulp; however, NMR spectroscopy is used for the first time to characterize the nutritional components of organic and aqueous-ethanolic extracts. This spectroscopic technique determined the triacylglycerols in the pequi organic fraction, which is constituted mainly by oleate and palmitate esters, and detected the carbohydrate mixtures as the major components of aqueous and ethanolic fractions, respectively. In this study, presence of phenolic compounds was only evidenced in the ethanolic fraction. (author)

Vibrational Characterizations of Zn0.72Li0.28O/Si Thin Films Studied by Fourier Transform Raman Spectroscopy

International Nuclear Information System (INIS)

Myo Myat Thet; Win Kyaw; Yin Maung Maung; Ko Ko Kyaw Soe

2008-03-01

The Zn0.72Li0.28O/Si (x = 0.28mol%) thin layers were fabricated on p-Si(100) substrate with five different process temperature. Vibrational characterizations of those thin films were investigated by FT- Raman spectroscopy. The resulted spectral line characters have been compared with that of Zn0.72Li0.28O/Glass thin films. Some vibrational motions of starting materials and final(candidate) thin films molecules were found in two substrates of glass and Si and vibrational frequencies were assigned by using molecular spectroscopy. Most of the frequencies of starting and final materials were found to be shifted in each of the films of two different substrates.

Stability of FDTS monolayer coating on aluminum injection molding tools

International Nuclear Information System (INIS)

Cech, Jiri; Taboryski, Rafael

2012-01-01

Highlights: ► We present novel and highly useful results on FDTS monolayer coating of aluminum. ► The coating is particularly applicable for coating of prototyping injection molding tools, which often are made of Al. ► We have demonstrated that the coating prevails in injection molding conditions and that the coating will prevent wear of the tools. - Abstract: We have characterized perfluorodecyltrichlorosilane (FDTS) molecular coating of aluminum molds for polymer replication via injection molding (IM). X-ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energies and roughness data have been collected. Samples have been characterized immediately after coating, after more than 500 IM cycles to test durability, and after 7 months to test temporal stability. The coating was deposited in an affordable process, involving near room temperature gas phase reactions. XPS shows detectable fluorine presence on both freshly coated samples as well as on post-IM samples with estimated 30 at.% on freshly coated and 28 at.% on post-IM samples with more than 500 IM cycles with polystyrene (PS) and ABS polymer.

Characterization of transition metal-containing oxide systems by Mössbauer Spectroscopy

Directory of Open Access Journals (Sweden)

Z. Homonnay

2004-12-01

Full Text Available High-temperature (high-Tc superconductors and colossal magnetoresistant (CMR materials belong to the most promising materials of the past 2-3 decades for technical applications. Most of them are oxides and the crucial element which determines their useful physical properties is often a transition metal (Cu, Co, Fe, Mn. 57Fe Mössbauer Spectroscopy can be used to characterize the electronic and structural properties of transition metal-containing oxides by providing information on the local electronic structure of the lattice site where the Mössbauer probe is accommodated. By reviewing several Mössbauer studies, it is demonstrated how the layered (2D electronic structure of high-Tc superconductors can be deduced from the analysis of the Mössbauer isomer shift and quadrupole splitting. We also show how the Mössbauer isomer shift indicates metallicity of the ferromagnetic phase in the CMR material LaxSr1-xCoO3.

Protein folding on the ribosome studied using NMR spectroscopy

Science.gov (United States)

Waudby, Christopher A.; Launay, Hélène; Cabrita, Lisa D.; Christodoulou, John

2013-01-01

NMR spectroscopy is a powerful tool for the investigation of protein folding and misfolding, providing a characterization of molecular structure, dynamics and exchange processes, across a very wide range of timescales and with near atomic resolution. In recent years NMR methods have also been developed to study protein folding as it might occur within the cell, in a de novo manner, by observing the folding of nascent polypeptides in the process of emerging from the ribosome during synthesis. Despite the 2.3 MDa molecular weight of the bacterial 70S ribosome, many nascent polypeptides, and some ribosomal proteins, have sufficient local flexibility that sharp resonances may be observed in solution-state NMR spectra. In providing information on dynamic regions of the structure, NMR spectroscopy is therefore highly complementary to alternative methods such as X-ray crystallography and cryo-electron microscopy, which have successfully characterized the rigid core of the ribosome particle. However, the low working concentrations and limited sample stability associated with ribosome–nascent chain complexes means that such studies still present significant technical challenges to the NMR spectroscopist. This review will discuss the progress that has been made in this area, surveying all NMR studies that have been published to date, and with a particular focus on strategies for improving experimental sensitivity. PMID:24083462

Intracellular formation of α-synuclein oligomers and the effect of heat shock protein 70 characterized by confocal single particle spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Levin, Johannes [Department of Neurology, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); German Center for Neurodegenerative Diseases – DZNE, Site Munich, Feodor-Lynen-Str. 17, 81377 Munich (Germany); Hillmer, Andreas S. [Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Feodor-Lynen-Str. 23, 81377 Munich (Germany); Högen, Tobias [Department of Neurology, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); McLean, Pamela J. [Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 (United States); Giese, Armin, E-mail: armin.giese@med.uni-muenchen.de [Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Feodor-Lynen-Str. 23, 81377 Munich (Germany)

2016-08-12

Synucleinopathies such as dementia with Lewy bodies or Parkinson’s disease are characterized by intracellular deposition of pathologically aggregated α-synuclein. The details of the molecular pathogenesis of PD and especially the conditions that lead to intracellular aggregation of α-synuclein and the role of these aggregates in cell death remain unknown. In cell free in vitro systems considerable knowledge about the aggregation processes has been gathered. In comparison, the knowledge about these aggregation processes in cells is far behind. In cells α-synuclein aggregates can be toxic. However, the crucial particle species responsible for decisive steps in pathogenesis such as seeding a continuing aggregation process and triggering cell death remain to be identified. In order to understand the complex nature of intracellular α-synuclein aggregate formation, we analyzed fluorescent particles formed by venus and α-synuclein-venus fusion proteins and α-synuclein-hemi-venus fusion proteins derived from gently lyzed cells. With these techniques we were able to identify and characterize α-synuclein oligomers formed in cells. Especially the use of α-synuclein-hemi-venus fusion proteins enabled us to identify very small α-synuclein oligomers with high sensitivity. Furthermore, we were able to study the molecular effect of heat shock protein 70, which is known to inhibit α-synuclein aggregation in cells. Heat shock protein 70 does not only influence the size of α-synuclein oligomers, but also their quantity. In summary, this approach based on fluorescence single particle spectroscopy, that is suited for high throughput measurements, can be used to detect and characterize intracellularly formed α-synuclein aggregates and characterize the effect of molecules that interfere with α-synuclein aggregate formation. - Highlights: • Single particle spectroscopy detects intracellular formed α-synuclein aggregates. • Fusion proteins allow detection of protein

Combining fibre optic Raman spectroscopy and tactile resonance measurement for tissue characterization

International Nuclear Information System (INIS)

Candefjord, Stefan; Nyberg, Morgan; Ramser, Kerstin; Lindahl, Olof A; Jalkanen, Ville

2010-01-01

Tissue characterization is fundamental for identification of pathological conditions. Raman spectroscopy (RS) and tactile resonance measurement (TRM) are two promising techniques that measure biochemical content and stiffness, respectively. They have potential to complement the golden standard-–histological analysis. By combining RS and TRM, complementary information about tissue content can be obtained and specific drawbacks can be avoided. The aim of this study was to develop a multivariate approach to compare RS and TRM information. The approach was evaluated on measurements at the same points on porcine abdominal tissue. The measurement points were divided into five groups by multivariate analysis of the RS data. A regression analysis was performed and receiver operating characteristic (ROC) curves were used to compare the RS and TRM data. TRM identified one group efficiently (area under ROC curve 0.99). The RS data showed that the proportion of saturated fat was high in this group. The regression analysis showed that stiffness was mainly determined by the amount of fat and its composition. We concluded that RS provided additional, important information for tissue identification that was not provided by TRM alone. The results are promising for development of a method combining RS and TRM for intraoperative tissue characterization

Using Dielectric Relaxation Spectroscopy to Characterize the Glass Transition Time of Polydextrose.

Science.gov (United States)

Buehler, Martin G; Kindle, Michael L; Carter, Brady P

2015-06-01

Dielectric relaxation spectroscopy was used to characterize the glass transition time, tg , of polydextrose, where the glass transition temperature, Tg , and water activity, aw (relative humidity), were held constant during polydextrose relaxation. The tg was determined from a shift in the peak frequency of the imaginary capacitance spectrum with time. It was found that when the peak frequency reaches 30 mHz, polydextrose undergoes glass transition. Glass transition time, tg , is the time for polydextrose to undergo glass transition at a specific Tg and aw . Results lead to a modified state diagram, where Tg is depressed with increasing aw . This curve forms a boundary: (a) below the boundary, polydextrose does not undergo glass transition and (b) above the boundary, polydextrose rapidly undergoes glass transition. As the boundary curve is specified by a tg value, it can assist in the selection of storage conditions. An important point on the boundary curve is at aw = 0, where Tg0 = 115 °C. The methodology can also be used to calculate the stress-relaxation viscosity of polydextrose as a function of Tg and aw , which is important when characterizing the flow properties of polydextrose initially in powder form. © 2015 Institute of Food Technologists®

Applicability of FTIR-spectroscopy for characterizing waste organic matter

International Nuclear Information System (INIS)

Smidt, E.

2001-12-01

State and development of waste organic matter were characterized by means of FTIR-spectroscopy. Due to the interaction of infrared light with matter energy is absorbed by chemical functional groups. Chemical preparation steps are not necessary and therefore this method offers a more holistic information about the material. The first part of experiments was focussed on spectra of different waste materials representing various stages of decomposition. Due to characteristics in the fingerprint- region the identity of wastes is provable. Heights of significant bands in the spectrum were measured and relative absorbances were calculated. Changes of relative absorbances indicate the development of organic matter during decomposition. Organic matter of waste samples was compared to organic matter originating from natural analogous processes (peat, soil). The second part of experiments concentrated on a composting process for a period of 260 days. Spectral characteristics of the samples were compared to their chemical, physical and biological data. The change of relative absorbances was reflected by conventional parameters. According to the development of the entire sample humic acids underwent a change as well. For practical use the method offers several possibilities: monitoring of a process, comparison of different processes, quality control of products originating from waste materials and the proof of their identity. (author)

Characterization of Nuclear Materials Using Complex of Non-Destructive and Mass-Spectroscopy Methods of Measurements

International Nuclear Information System (INIS)

Gorbunova, A.; Kramchaninov, A.

2015-01-01

Information and Analytical Centre for nuclear materials investigations was established in Russian Federation in the February 2 of 2009 by ROSATOM State Atomic Energy Corporation (the order #80). Its purpose is in preventing unauthorized access to nuclear materials and excluding their illicit traffic. Information and Analytical Centre includes analytical laboratory to provide composition and properties of nuclear materials of unknown origin for their identification. According to Regulation the Centre deals with: · identification of nuclear materials of unknown origin to provide information about their composition and properties; · arbitration analyzes of nuclear materials; · comprehensive research of nuclear and radioactive materials for developing techniques characterization of materials; · interlaboratory measurements; · measurements for control and accounting; · confirmatory measurements. Complex of non-destructive and mass-spectroscopy techniques was developed for the measurements. The complex consists of: · gamma-ray techniques on the base of MGAU, MGA and FRAM codes for uranium and plutonium isotopic composition; · gravimetrical technique with gamma-spectroscopy in addition for uranium content; · calorimetric technique for plutonium mass; · neutron multiplicity technique for plutonium mass; · measurement technique on the base of mass-spectroscopy for uranium isotopic composition; · measurement technique on the base of mass-spectroscopy for metallic impurities. Complex satisfies the state regulation requirements of ensuring the uniformity of measurements including the Russian Federation Federal Law on Ensuring the Uniformity of Measurements #102-FZ, Interstate Standard GOST R ISO/IEC 17025-2006, National Standards of Russian Federation GOST R 8.563-2009, GOST R 8.703-2010, Federal Regulations NRB-99/2009, OSPORB 99/2010. Created complex is provided in reference materials, equipment end certificated techniques. The complex is included in accredited

Vibrational Micro-Spectroscopy of Human Tissues Analysis: Review.

Science.gov (United States)

Bunaciu, Andrei A; Hoang, Vu Dang; Aboul-Enein, Hassan Y

2017-05-04

Vibrational spectroscopy (Infrared (IR) and Raman) and, in particular, micro-spectroscopy and micro-spectroscopic imaging have been used to characterize developmental changes in tissues, to monitor these changes in cell cultures and to detect disease and drug-induced modifications. The conventional methods for biochemical and histophatological tissue characterization necessitate complex and "time-consuming" sample manipulations and the results are rarely quantifiable. The spectroscopy of molecular vibrations using mid-IR or Raman techniques has been applied to samples of human tissue. This article reviews the application of these vibrational spectroscopic techniques for analysis of biological tissue published between 2005 and 2015.

ESR spectroscopy - an analytical tool for the glass industry

International Nuclear Information System (INIS)

Elvers, A.; Weissmann, R.

2001-01-01

In the past, wet chemical methods have been developed for the quantitative analysis of polyvalent elements in glasses. The major disadvantage of these chemical methods is that all structural information is lost during analysis. In addition, the analysis of species by wet chemical methods is unreliable due to possible redox reactions during the decomposition process. Therefore, the emphasis is on the physical methods which can directly detect species in bulk glasses. Especially optical and ESR spectroscopy are suitable methods due to their wide range of applications and sensitivity. Concerning quantitative measurements, no comparison between ESR results and chemical analysis of species has been published so far. This work discusses the possible application of ESR spectroscopy in the glass industry by focussing on routine interpretation, the correlation to chemical procedures and quantitative analysis. Results are presented and discussed for iron and chromium in packaging glasses. For example an excellent correlation was found between the Fe 3+ ESR signal and the chemically determined Fe 3+ concentration in glass. (orig.)

Raman spectroscopy as a tool for ecology and evolution.

Science.gov (United States)

Germond, Arno; Kumar, Vipin; Ichimura, Taro; Moreau, Jerome; Furusawa, Chikara; Fujita, Hideaki; Watanabe, Tomonobu M

2017-06-01

Scientists are always on the lookout for new modalities of information which could reveal new biological features that are useful for deciphering the complexity of biological systems. Here, we introduce Raman spectroscopy as a prime candidate for ecology and evolution. To encourage the integration of this microscopy technique in the field of ecology and evolution, it is crucial to discuss first how Raman spectroscopy fits within the conceptual, technical and pragmatic considerations of ecology and evolution. In this paper, we show that the spectral information holds reliable indicators of intra- and interspecies variations, which can be related to the environment, selective pressures and fitness. Moreover, we show how the technical and pragmatic aspects of this modality (non-destructive, non-labelling, speed, relative low cost, etc.) enable it to be combined with more conventional methodologies. With this paper, we hope to open new avenues of research and extend the scope of available methodologies used in ecology and evolution. © 2017 The Authors.

NIR & MIR spectroscopy as an effective tool for detecting urban influences on soils

Science.gov (United States)

Brook, Anna; Kopel, Daniella; Wittenberg, Lea

2016-04-01

Soil supports ecosystem functions and services, sustains ecosystems and biodiversity, yet in the urban spreading world of today, soil as a resource is in constant danger. Human society takes for granted the services provided by open green patches allocated within and nearby cities, with no consideration of ramifications of urban development on those areas. The urban ecology science recognizes the need to learn, identify and monitor the soils of cities - urban soils. The definitions of those soils are mainly descriptive, since urban soils do not submitted to the pedological process as natural soils. The main objective of this paper is to characterize urban soils in open green undisturbed patches by mineralogical composition. This goal was achieved using field and laboratory spectroscopy across visible near, short wave infrared regions and laboratory thermal mid infrared region. The majority of the studies on urban soils concentrate on identifying and mapping of pollution mostly heavy metals. In this study a top-down analysis (a simple and intuitive spectral feature for detecting the presence of minerals, organic matter and pollutants in mixed soil samples) is applied. This method uses spectral activity (SA) detection in a structured hierarchical approach to quickly and, more importantly, correctly identify dominant spectral features. The applied method is adopted by multiple in-production tools including continuum removal normalization, guided by polynomial generalization, and spectral-likelihood algorithms: orthogonal subspace projection (OSP) and iterative spectral mixture analysis (ISMA) were compared to feature likelihood methods. A total of 70 soil samples were collected at different locations: in remnant area within the city (edge and core), on the borders of the neighborhoods (edge) and in the fringe zone and in 2 locations in the protected park. The park samples were taken in locations found more than 100m from roads or direct anthropogenic disturbances. The

Analytical characterization using surface-enhanced Raman scattering (SERS) and microfluidic sampling

International Nuclear Information System (INIS)

Wang, Chao; Yu, Chenxu

2015-01-01

With the rapid development of analytical techniques, it has become much easier to detect chemical and biological analytes, even at very low detection limits. In recent years, techniques based on vibrational spectroscopy, such as surface enhanced Raman spectroscopy (SERS), have been developed for non-destructive detection of pathogenic microorganisms. SERS is a highly sensitive analytical tool that can be used to characterize chemical and biological analytes interacting with SERS-active substrates. However, it has always been a challenge to obtain consistent and reproducible SERS spectroscopic results at complicated experimental conditions. Microfluidics, a tool for highly precise manipulation of small volume liquid samples, can be used to overcome the major drawbacks of SERS-based techniques. High reproducibility of SERS measurement could be obtained in continuous flow generated inside microfluidic devices. This article provides a thorough review of the principles, concepts and methods of SERS-microfluidic platforms, and the applications of such platforms in trace analysis of chemical and biological analytes. (topical review)

Characterization of amorphous and nanocrystalline carbon films

International Nuclear Information System (INIS)

Chu, Paul K.; Li Liuhe

2006-01-01

Amorphous and nanocrystalline carbon films possess special chemical and physical properties such as high chemical inertness, diamond-like properties, and favorable tribological proprieties. The materials usually consist of graphite and diamond microstructures and thus possess properties that lie between the two. Amorphous and nanocrystalline carbon films can exist in different kinds of matrices and are usually doped with a large amount of hydrogen. Thus, carbon films can be classified as polymer-like, diamond-like, or graphite-like based on the main binding framework. In order to characterize the structure, either direct bonding characterization methods or the indirect bonding characterization methods are employed. Examples of techniques utilized to identify the chemical bonds and microstructure of amorphous and nanocrystalline carbon films include optical characterization methods such as Raman spectroscopy, Ultra-violet (UV) Raman spectroscopy, and infrared spectroscopy, electron spectroscopic and microscopic methods such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, transmission electron microscopy, and electron energy loss spectroscopy, surface morphology characterization techniques such as scanning probe microscopy (SPM) as well as other characterization methods such as X-ray reflectivity and nuclear magnetic resonance. In this review, the structures of various types of amorphous carbon films and common characterization techniques are described

Fourier transform near-infrared spectroscopy application for sea salt quality evaluation.

Science.gov (United States)

Galvis-Sánchez, Andrea C; Lopes, João Almeida; Delgadillo, Ivonne; Rangel, António O S S

2011-10-26

Near-infrared (NIR) spectroscopy in diffuse reflectance mode was explored with the objective of discriminating sea salts according to their quality type (traditional salt vs "flower of salt") and geographical origin (Atlantic vs Mediterranean). Sea salts were also analyzed in terms of Ca(2+), Mg(2+), K(+), alkalinity, and sulfate concentrations to support spectroscopic results. High concentrations of Mg(2+) and K(+) characterized Atlantic samples, while a high Ca(2+) content was observed in traditional sea salts. A partial least-squares discriminant analysis model considering the 8500-7500 cm(-1) region permitted the discrimination of salts by quality types. The regions 4650-4350 and 5900-5500 cm(-1) allowed salts classification according to their geographical origin. It was possible to classify correctly 85.3 and 94.8% of the analyzed samples according to the salt type and to the geographical origin, respectively. These results demonstrated that NIR spectroscopy is a suitable and very efficient tool for sea salt quality evaluation.

Characterization and wear performance of boride phases over tool steel substrates

Directory of Open Access Journals (Sweden)

Edgar E Vera Cárdenas

2016-02-01

Full Text Available This research work was conducted to characterize boride phases, obtained from the powder-pack process, on AISI H13 and D2 steel substrates, and investigate their tribological behavior. The boriding was developed at a temperature of 1273 K with an exposure time of 8 h. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were conducted on the borided material to characterize the presence of the FeB, Fe2B, and CrB phases and the distribution of heavy elements on the surface of the substrates. The adherence of the boride layers was evaluated, in a qualitative form, through the Daimler-Benz Rockwell-C indentation technique. Sliding wear tests were then performed using a reciprocating wear test machine. All tests were conducted in dry conditions at room temperature. A frequency of 10 Hz and 15-mm sliding distance were used. The applied Hertzian pressure was 2.01 GPa. Scanning electron microscopy was used to observe and analyze the wear mechanisms. Additionally, the variation of the friction coefficient versus the number of cycles was obtained. Experimental results showed that the characteristic wear mechanism for the borided surface was plastic deformation and mild abrasive wear; for unborided substrates, cracking and spalling were observed.

Raman spectroscopy in pharmaceutical product design

DEFF Research Database (Denmark)

Paudel, Amrit; Raijada, Dhara; Rantanen, Jukka

2015-01-01

Almost 100 years after the discovery of the Raman scattering phenomenon, related analytical techniques have emerged as important tools in biomedical sciences. Raman spectroscopy and microscopy are frontier, non-invasive analytical techniques amenable for diverse biomedical areas, ranging from...... molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant...... application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed....

GEOMETRICAL CHARACTERIZATION OF MICRO END MILLING TOOLS

DEFF Research Database (Denmark)

Borsetto, Francesca; Bariani, Paolo

The milling process is one of the most common metal removal operation used in industry. This machining process is well known since the beginning of last century and has experienced, along the years, many improvements of the basic technology, as concerns tools, machine tools, coolants/lubricants, ......The milling process is one of the most common metal removal operation used in industry. This machining process is well known since the beginning of last century and has experienced, along the years, many improvements of the basic technology, as concerns tools, machine tools, coolants....../lubricants, milling strategies and controls. Moreover the accuracy of tool geometry directly affects the performance of the milling process influencing the dimensional tolerances of the machined part, the surface topography, the chip formation, the cutting forces and the tool-life. The dimensions of certain...... geometrical details, as for instance the cutting edge radius, are determined by characteristics of the manufacturing process, tool material, coating etc. While for conventional size end mills the basic tool manufacturing process is well established, the reduction of the size of the tools required...

Quantitative Studies of Antimicrobial Peptide Pore Formation in Large Unilamellar Vesicles by Fluorescence Correlation Spectroscopy (FCS)

DEFF Research Database (Denmark)

Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

2013-01-01

In spite of intensive research efforts over the past decades, the mechanisms by which membrane-active antimicrobial peptides interact with phospholipid membranes are not yet fully elucidated. New tools that can be used to characterize antimicrobial peptide-lipid membrane interactions are therefore...... to quantify leakage from large unilamellar vesicles is associated with a number of experimental pitfalls. Based on theoretical and experimental considerations, we discuss how to properly design experiments to avoid these pitfalls. Subsequently, we apply fluorescence correlation spectroscopy to quantify...

Characterization of toners and inkjets by laser ablation spectrochemical methods and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy

Science.gov (United States)

Trejos, Tatiana; Corzo, Ruthmara; Subedi, Kiran; Almirall, José

2014-02-01

Detection and sourcing of counterfeit currency, examination of counterfeit security documents and determination of authenticity of medical records are examples of common forensic document investigations. In these cases, the physical and chemical composition of the ink entries can provide important information for the assessment of the authenticity of the document or for making inferences about common source. Previous results reported by our group have demonstrated that elemental analysis, using either Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) or Laser Ablation Induced Breakdown Spectroscopy (LIBS), provides an effective, practical and robust technique for the discrimination of document substrates and writing inks with minimal damage to the document. In this study, laser-based methods and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) methods were developed, optimized and validated for the forensic analysis of more complex inks such as toners and inkjets, to determine if their elemental composition can differentiate documents printed from different sources and to associate documents that originated from the same printing source. Comparison of the performance of each of these methods is presented, including the analytical figures of merit, discrimination capability and error rates. Different calibration strategies resulting in semi-quantitative and qualitative analysis, comparison methods (match criteria) and data analysis and interpretation tools were also developed. A total of 27 black laser toners originating from different manufacturing sources and/or batches were examined to evaluate the discrimination capability of each method. The results suggest that SEM-EDS offers relatively poor discrimination capability for this set (~ 70.7% discrimination of all the possible comparison pairs or a 29.3% type II error rate). Nonetheless, SEM-EDS can still be used as a complementary method of analysis since it has

Characterization of control mesoporous glasses (CPGs) using positron annihilation lifetime spectroscopy (PALS)

Energy Technology Data Exchange (ETDEWEB)

Sayed Ahmed, Essmat Mahmoud Hassan

2008-01-30

This thesis has two main goals. Firstly and for the first time, the positron annihilation lifetime technique (PALS) is used to characterize the control porous glasses (CPGs) media. All the positron annihilation spectroscopy (PAS) investigations have been interested in the commercial Vycor glass media of pores size {<=} 4 nm. Therefore, the PALS is used to establish basic correlations between the important physical properties of the CPG (pore size, surface area, and porosity) and the orthopositronium (o-Ps) lifetime. The second goal is to use these correlations to verify the validity of some suggested models and theories to discover possible deviations from the expected behaviour and to discuss the physical point of view for these deviations. Chapter 1 presents an overview of positron, positronium and their interaction with solid materials. Chapter 2 of this thesis is concerned with characterization of porous glass materials. This chapter discusses in detail the preparation methods of porous glasses specially control porous glass and Vycor glass. The gas adsorption phenomenon in porous glass and the related definitions are discussed. The most important terms of the porous glass such as pore size, shape, volume, pore size distribution, surface area, and porosity are discussed. Chapter 3 presents in detail the well known models and the derived equations which correlate between the lifetime of the o-Ps long-lived component and the pore size, pore shape and the temperature dependence of the porous media. Chapter 4 presents an overview of the main experimental techniques used in this thesis, namely positron annihilation lifetime spectroscopy. Chapter 5 explains the sample preparation for the measurements. The chapter represents also the experimental data for the correlation between the o-Ps lifetime and pore sizes for a system of CPG media (from 1 nm to 64 nm). I also studied the temperature dependence of the o-Ps long-lived component in different pore sizes. In this

Characterization of control mesoporous glasses (CPGs) using positron annihilation lifetime spectroscopy (PALS)

International Nuclear Information System (INIS)

Sayed Ahmed, Essmat Mahmoud Hassan

2008-01-01

This thesis has two main goals. Firstly and for the first time, the positron annihilation lifetime technique (PALS) is used to characterize the control porous glasses (CPGs) media. All the positron annihilation spectroscopy (PAS) investigations have been interested in the commercial Vycor glass media of pores size ≤ 4 nm. Therefore, the PALS is used to establish basic correlations between the important physical properties of the CPG (pore size, surface area, and porosity) and the orthopositronium (o-Ps) lifetime. The second goal is to use these correlations to verify the validity of some suggested models and theories to discover possible deviations from the expected behaviour and to discuss the physical point of view for these deviations. Chapter 1 presents an overview of positron, positronium and their interaction with solid materials. Chapter 2 of this thesis is concerned with characterization of porous glass materials. This chapter discusses in detail the preparation methods of porous glasses specially control porous glass and Vycor glass. The gas adsorption phenomenon in porous glass and the related definitions are discussed. The most important terms of the porous glass such as pore size, shape, volume, pore size distribution, surface area, and porosity are discussed. Chapter 3 presents in detail the well known models and the derived equations which correlate between the lifetime of the o-Ps long-lived component and the pore size, pore shape and the temperature dependence of the porous media. Chapter 4 presents an overview of the main experimental techniques used in this thesis, namely positron annihilation lifetime spectroscopy. Chapter 5 explains the sample preparation for the measurements. The chapter represents also the experimental data for the correlation between the o-Ps lifetime and pore sizes for a system of CPG media (from 1 nm to 64 nm). I also studied the temperature dependence of the o-Ps long-lived component in different pore sizes. In this

Infrared imaging spectroscopy and chemometric tools for in situ analysis of an imiquimod pharmaceutical preparation presented as cream

Science.gov (United States)

Carneiro, Renato Lajarim; Poppi, Ronei Jesus

2014-01-01

In the present work the homogeneity of a pharmaceutical formulation presented as a cream was studied using infrared imaging spectroscopy and chemometric methodologies such as principal component analysis (PCA) and multivariate curve resolution with alternating least squares (MCR-ALS). A cream formulation, presented as an emulsion, was prepared using imiquimod as the active pharmaceutical ingredient (API) and the excipients: water, vaseline, an emulsifier and a carboxylic acid in order to dissolve the API. After exposure at 45 °C during 3 months to perform accelerated stability test, the presence of some crystals was observed, indicating homogeneity problems in the formulation. PCA exploratory analysis showed that the crystal composition was different from the composition of the emulsion, since the score maps presented crystal structures in the emulsion. MCR-ALS estimated the spectra of the crystals and the emulsion. The crystals presented amine and C-H bands, suggesting that the precipitate was a salt formed by carboxylic acid and imiquimod. These results indicate the potential of infrared imaging spectroscopy in conjunction with chemometric methodologies as an analytical tool to ensure the quality of cream formulations in the pharmaceutical industry.

Characterization of different cassava samples by nuclear magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Iulianelli, Gisele C.V.; Tavares, Maria I.B.

2011-01-01

Cassava root (Manihot esculenta Crantz) is grown in all Brazilian states, being an important product in the diet of Brazilians. For many families of the North and Northeast states, it may represent the main energy source. The cassava root flour has high levels of starch, in addition to containing fiber, lipids and some minerals. There is, however, great genetic variability, which results in differentiation in its chemical composition and structural aspect. Motivated by the economic, nutritional and pharmacological importance of this product, this work is aimed at characterizing six cassava flour samples by NMR spectroscopy. The spectra revealed the main chemical groups. Furthermore, the results confirmed differences on chemical and structural aspect of the samples. For instance, the F1 sample is richer in carbohydrates, while the F4 sample has higher proportion of glycolipids, the F2 sample has higher amylose content and the F6 sample exhibits a greater diversity of glycolipid types. Regarding the molecular structure, the NMR spectra indicated that the F1 sample is more organized at the molecular level, while the F3 and F5 samples are similar in amorphicity and in the molecular packing. (author)

Characterization of solar cell materials by Proton Back Scattering Spectroscopy

International Nuclear Information System (INIS)

Joynal Abedin, M.; Fazlul Hoque, A.K.M.; Firoz Hasan, S.M.

2001-01-01

The need for accurate chemical characterization of samples specially related to electronic and solar cell materials has assumed increasing importance in recent years. The importance of the study of the surfaces of materials of different origin also increased in recent years to a great extent. This need has created a worldwide spurt to develop rapid, accurate and sensitive tools for the characterization of materials. In recent years the proton backscattering spectrometry (PBS) method has been recognized as one of the useful analytical tool in several applications of material analysis and technology. The lack of information of the relevant scattering cross sections as a function of proton energy and the problems arising in conventional data analysis have so far rendered proton backscattering analysis of multielemental samples difficult at low energies. On the other hand advances in the computer evaluation of experimental data have, however, made it possible to utilize low-MeV protons as a sensitive probe for light elements in the μm range. The benefits of the method in comparison to alpha particle backscattering include the relatively higher non-Rutherford scattering cross sections of the light elements and to the lower proton stopping in the target material. These lead to higher sensitivity in detecting and profiling light elements in heavy targets and to significantly larger accessible depths and smaller straggling than with alpha particles. Research works on the development of methodologies of Proton Backscattering Spectrometry (PBS) for the analysis of thin films and surfaces has been in progress in the 3 MeV Van de Graaff Accelerator facilities of Atomic Energy Centre, Dhaka for some years. The PBS system comprises a target chamber with appropriate sample holders and a Surface Barrier Detector (SBD) with the associated electronics for data acquisition and reduction. For the evaluation of the PBS data RBS Universal Master Package, RUMP has been installed in the

Characterization of carotenoids in soil bacteria and investigation of their photodegradation by UVA radiation via resonance Raman spectroscopy.

Science.gov (United States)

Kumar B N, Vinay; Kampe, Bernd; Rösch, Petra; Popp, Jürgen

2015-07-07

A soil habitat consists of an enormous number of pigmented bacteria with the pigments mainly composed of diverse carotenoids. Most of the pigmented bacteria in the top layer of the soil are photoprotected from exposure to huge amounts of UVA radiation on a daily basis by these carotenoids. The photostability of these carotenoids depends heavily on the presence of specific features like a carbonyl group or an ionone ring system on its overall structure. Resonance Raman spectroscopy is one of the most sensitive and powerful techniques to detect and characterize these carotenoids and also monitor processes associated with them in their native system at a single cell resolution. However, most of the resonance Raman profiles of carotenoids have very minute differences, thereby making it extremely difficult to confirm if these differences are attributed to the presence of different carotenoids or if it is a consequence of their interaction with other cellular components. In this study, we devised a method to overcome this problem by monitoring also the photodegradation of the carotenoids in question by UVA radiation wherein a differential photodegradation response will confirm the presence of different carotenoids irrespective of the proximities in their resonance Raman profiles. Using this method, the detection and characterization of carotenoids in pure cultures of five species of pigmented coccoid soil bacteria is achieved. We also shed light on the influence of the structure of the carotenoid on its photodegradation which can be exploited for use in the characterization of carotenoids via resonance Raman spectroscopy.

Characterization of hard nitride and carbide titanium and zirconium coatings on high-speed steel cutting tool inserts

International Nuclear Information System (INIS)

Fenske, G.; Kaufherr, N.; Albertson, C.; Mapalo, G.; Nielsen, R.; Kaminsky, M.

1986-01-01

Hard nitride and carbide coatings of titanium and zirconium deposited by reactive evaporation and reactive sputtering techniques were characterized by electron microscopy and Auger spectroscopy to determine the effect of coating process on coating composition and microstructure. Analysis of the chemical composition by Auger spectroscopy revealed the coatings were of high purity with slight differences in stoichiometry depending on the coating technique. Both techniques produced coatings with a columnar microstructure. However, the reactive sputtering technique produced coarser (shorter and wider) columnar grains than the reactive evaporation technique. Furthermore, selected area diffraction analysis of reactively sputtered ZrN coatings showed a two-phased zone (hcp Zr and fcc ZrN) near the substrate/coating interface, while TiC coatings deposited by reactive sputtering and evaporation only showed a single-phase region of fcc TiC

Online characterization of planetary surfaces: PlanetServer, an open-source analysis and visualization tool

Science.gov (United States)

Marco Figuera, R.; Pham Huu, B.; Rossi, A. P.; Minin, M.; Flahaut, J.; Halder, A.

2018-01-01

The lack of open-source tools for hyperspectral data visualization and analysis creates a demand for new tools. In this paper we present the new PlanetServer, a set of tools comprising a web Geographic Information System (GIS) and a recently developed Python Application Programming Interface (API) capable of visualizing and analyzing a wide variety of hyperspectral data from different planetary bodies. Current WebGIS open-source tools are evaluated in order to give an overview and contextualize how PlanetServer can help in this matters. The web client is thoroughly described as well as the datasets available in PlanetServer. Also, the Python API is described and exposed the reason of its development. Two different examples of mineral characterization of different hydrosilicates such as chlorites, prehnites and kaolinites in the Nili Fossae area on Mars are presented. As the obtained results show positive outcome in hyperspectral analysis and visualization compared to previous literature, we suggest using the PlanetServer approach for such investigations.

Detection Limits of DLS and UV-Vis Spectroscopy in Characterization of Polydisperse Nanoparticles Colloids

Directory of Open Access Journals (Sweden)

Emilia Tomaszewska

2013-01-01

Full Text Available Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs colloids were studied using dynamic light scattering (DLS and ultraviolet-visible (UV-Vis spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM, transmission electron microscopy (TEM, DLS, and UV-Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV-Vis only.

In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

KAUST Repository

Maher, R. C.; Duboviks, V.; Offer, G.; Cohen, L. F.; Brandon, N. P.

2013-01-01

Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

KAUST Repository

Maher, R. C.

2013-10-06

Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

Photoacoustic spectroscopy of β-hematin

International Nuclear Information System (INIS)

Samson, Edward B; Goldschmidt, Benjamin S; Whiteside, Paul J D; Sudduth, Amanda S M; Custer, John R; Viator, John A; Beerntsen, Brenda

2012-01-01

Malaria affects over 200 million individuals annually, resulting in 800 000 fatalities. Current tests use blood smears and can only detect the disease when 0.1–1% of blood cells are infected. We are investigating the use of photoacoustic flowmetry to sense as few as one infected cell among 10 million or more normal blood cells, thus diagnosing infection before patients become symptomatic. Photoacoustic flowmetry is similar to conventional flow cytometry, except that rare cells are targeted by nanosecond laser pulses to induce ultrasonic responses. This system has been used to detect single melanoma cells in 10 ml of blood. Our objective is to apply photoacoustic flowmetry to detection of the malaria pigment hemozoin, which is a byproduct of parasite-digested hemoglobin in the blood. However, hemozoin is difficult to purify in quantities greater than a milligram, so a synthetic analog, known as β-hematin was derived from porcine hemin. The specific purpose of this study is to establish the efficacy of using β-hematin, rather than hemozoin, for photoacoustic measurements. We characterized β-hematin using UV–vis spectroscopy, TEM, and FTIR, then tested the effects of laser irradiation on the synthetic product. We finally determined its absorption spectrum using photoacoustic excitation. UV–vis spectroscopy verified that β-hematin was distinctly different from its precursor. TEM analysis confirmed its previously established nanorod shape, and comparison of the FTIR results with published spectroscopy data showed that our product had the distinctive absorbance peaks at 1661 and 1206 cm −1 . Also, our research indicated that prolonged irradiation dramatically alters the physical and optical properties of the β-hematin, resulting in increased absorption at shorter wavelengths. Nevertheless, the photoacoustic absorption spectrum mimicked that generated by UV–vis spectroscopy, which confirms the accuracy of the photoacoustic method and strongly suggests

X-ray absorption spectroscopy: EXAFS and XANES - A versatile tool to study the atomic and electronic structure of materials

International Nuclear Information System (INIS)

Alp, E.E.; Mini, S.M.; Ramanathan, M.

1990-01-01

X-ray absorption spectroscopy (XAS) had been an essential tool to gather spectroscopic information about atomic energy level structure in the early decades of this century. The correct interpretation of the oscillatory structure in the x-ray absorption cross-section above the absorption edge has transformed XAS from a spectroscopic tool to a structural technique. EXAFS (Extended X-ray Absorption Fine Structure) yields information about the interatomic distances, near neighbor coordination numbers, and lattice dynamics. XANES (X-ray Absorption Near Edge Structure), on the other hand, gives information about the valence state, energy bandwidth and bond angles. Today, there are about 50 experimental stations in various synchrotrons around the world dedicated to collecting x-ray absorption data from the bulk and surfaces of solids and liquids. In this chapter, they will give the basic principles of XAS, explain the information content of essentially two different aspects of the absorption process leading to EXAFS and XANES, and discuss the source and sample limitations

Applications of Moessbauer spectroscopy to the structural characterization of minerals and products of the country 's mining - metallurgical industry

International Nuclear Information System (INIS)

Herrera Palma, Victoria; Cruz Inclan, Carlos Manuel

2016-01-01

Since the seventies of the past century Moessbauer Spectroscopy (MS) has been systematically and successfully applied at CEADEN in the study and characterization of lateritic and other iron-rich ores, and different products of their industrial processing as well. Due to their high iron and chrome content these materials seemed to be attractive as raw material for the production of several enriched fractions in metallurgical applications. Such studies showed that the systematic application of MS combined with X- Ray Diffraction and other techniques like neutron Diffraction, Thermal and Calorimetric analysis and Optical and Electron Microscopies, has allowed a higher level of accuracy in the crystallographic characterization, and the phase composition and other specific properties assessment. As examples in this direction, in the present paper results of the study on two different iron-bearing materials are reported: a) magnetite of Mina Grande (in Santiago de Cuba), and b) Monitoring of a proposed process using concentration tables for chrome enrichment from tailings of the nickel plant 'Hector Ramos Latour' at Holguin, both areas located in the east of Cuba. It is evidenced that a right combination of 57 Fe Moessbauer Spectroscopy with other mentioned methods is nowadays the wisest and most efficient way for a thorough identification and characterization of iron-bearing mineral ores and products in mining and metallurgical industry. (Author)

Characterization and discrimination of human breast cancer and normal breast tissues using resonance Raman spectroscopy

Science.gov (United States)

Wu, Binlin; Smith, Jason; Zhang, Lin; Gao, Xin; Alfano, Robert R.

2018-02-01

Worldwide breast cancer incidence has increased by more than twenty percent in the past decade. It is also known that in that time, mortality due to the affliction has increased by fourteen percent. Using optical-based diagnostic techniques, such as Raman spectroscopy, has been explored in order to increase diagnostic accuracy in a more objective way along with significantly decreasing diagnostic wait-times. In this study, Raman spectroscopy with 532-nm excitation was used in order to incite resonance effects to enhance Stokes Raman scattering from unique biomolecular vibrational modes. Seventy-two Raman spectra (41 cancerous, 31 normal) were collected from nine breast tissue samples by performing a ten-spectra average using a 500-ms acquisition time at each acquisition location. The raw spectral data was subsequently prepared for analysis with background correction and normalization. The spectral data in the Raman Shift range of 750- 2000 cm-1 was used for analysis since the detector has highest sensitivity around in this range. The matrix decomposition technique nonnegative matrix factorization (NMF) was then performed on this processed data. The resulting leave-oneout cross-validation using two selective feature components resulted in sensitivity, specificity and accuracy of 92.6%, 100% and 96.0% respectively. The performance of NMF was also compared to that using principal component analysis (PCA), and NMF was shown be to be superior to PCA in this study. This study shows that coupling the resonance Raman spectroscopy technique with subsequent NMF decomposition method shows potential for high characterization accuracy in breast cancer detection.

Characterization of nano-crystalline ZrO{sub 2} synthesized via reactive plasma processing

Energy Technology Data Exchange (ETDEWEB)

Jayakumar, S., E-mail: sjayakumar.physics@gmail.com [Research and Development Centre, Bharathiar University, Coimbatore 641 014 (India); Ananthapadmanabhan, P.V. [Laser and Plasma Technology Division, BARC, Trombay, Mumbai 400 085 (India); Perumal, K. [Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641 020 India (India); Thiyagarajan, T.K. [Laser and Plasma Technology Division, BARC, Trombay, Mumbai 400 085 (India); Mishra, S.C. [Department of Metallurgical and Materials Engg, National Institute of Technology, Rourkela 769 008 (India); Su, L.T.; Tok, A.I.Y.; Guo, J. [School of Materials Science and Engg, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639 798 (Singapore)

2011-07-25

Highlights: > Direct conversion of micron-sized zirconium hydride powder to nanocrystalline ZrO{sub 2} powder. > The experimental approach uses reactive plasma processing technique. > The product has been characterized by various analytical tools to support the findings. - Abstract: Nano-crystalline ZrO{sub 2} powder has been synthesized via reactive plasma processing. The synthesized ZrO{sub 2} powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM) and FTIR spectroscopy. The synthesized powder consists of a mixture of tetragonal and monoclinic phases of zirconia. Average crystallite size calculated from the XRD pattern shows that particles with crystallite size 20 nm or less than 20 nm are in tetragonal phase, whereas particles greater than 20 nm are in the monoclinic phase. TEM results show that particles have spherical morphology with maximum percentage of particles distributed in a narrow size from about 15 nm to 30 nm.

Characterization of Nuclear Materials in extreme conditions: the Raman spectroscopy approach

International Nuclear Information System (INIS)

Guimbretiere, G.; Canizares, A.; Simon, P.; Raimboux, N.; Ammar, M.R.; Duval, F.; Omnee, R.; Maslova, O.; Barthe, M.F.; Desgranges, L.; Caraballo, R.; Jegou, C.

2013-06-01

In this article, we review our last advances on the Raman spectroscopy characterization of irradiated and/or leached UO 2 , PuO 2 and (U, Pu)O 2 samples. For this, three original Raman setups dedicated to the study of nuclear materials were involved. In all cases, irradiation was observed inducing the appearance of Raman defect bands in the 500-750 cm -1 range. For UO 2 , annealing temperature experiment suggests that these defect bands may be the signatures of a medium range structured defect. Besides, the leaching experiments show different behavior between the in situ probed UO 2 ceramic and post mortem probed [UO 2 + (U, Pu)O 2 ] sample: In the first case we observed the growth of an altered layer made of studtite and schoepite phases. In the second we observed, in one hand the creation of U 3 O 8 and studtite phases at the surface of the UO 2 grains, in second hand no Raman signatures of any layer at the surface of the (U, Pu)O 2 grains. (authors)

Statistical process control for alpha spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Richardson, W; Majoras, R E [Oxford Instruments, Inc. P.O. Box 2560, Oak Ridge TN 37830 (United States); Joo, I O; Seymour, R S [Accu-Labs Research, Inc. 4663 Table Mountain Drive, Golden CO 80403 (United States)

1995-10-01

Statistical process control(SPC) allows for the identification of problems in alpha spectroscopy processes before they occur, unlike standard laboratory Q C which only identifies problems after a process fails. SPC tools that are directly applicable to alpha spectroscopy include individual X-charts and X-bar charts, process capability plots, and scatter plots. Most scientists are familiar with the concepts the and methods employed by SPC. These tools allow analysis of process bias, precision, accuracy and reproducibility as well as process capability. Parameters affecting instrument performance are monitored and analyzed using SPC methods. These instrument parameters can also be compared to sampling, preparation, measurement, and analysis Q C parameters permitting the evaluation of cause effect relationships. Three examples of SPC, as applied to alpha spectroscopy , are presented. The first example investigates background contamination using averaging to show trends quickly. A second example demonstrates how SPC can identify sample processing problems, analyzing both how and why this problem occurred. A third example illustrates how SPC can predict when an alpha spectroscopy process is going to fail. This allows for an orderly and timely shutdown of the process to perform preventative maintenance, avoiding the need to repeat costly sample analyses. 7 figs., 2 tabs.

Statistical process control for alpha spectroscopy

International Nuclear Information System (INIS)

Richardson, W.; Majoras, R.E.; Joo, I.O.; Seymour, R.S.

1995-01-01

Statistical process control(SPC) allows for the identification of problems in alpha spectroscopy processes before they occur, unlike standard laboratory Q C which only identifies problems after a process fails. SPC tools that are directly applicable to alpha spectroscopy include individual X-charts and X-bar charts, process capability plots, and scatter plots. Most scientists are familiar with the concepts the and methods employed by SPC. These tools allow analysis of process bias, precision, accuracy and reproducibility as well as process capability. Parameters affecting instrument performance are monitored and analyzed using SPC methods. These instrument parameters can also be compared to sampling, preparation, measurement, and analysis Q C parameters permitting the evaluation of cause effect relationships. Three examples of SPC, as applied to alpha spectroscopy , are presented. The first example investigates background contamination using averaging to show trends quickly. A second example demonstrates how SPC can identify sample processing problems, analyzing both how and why this problem occurred. A third example illustrates how SPC can predict when an alpha spectroscopy process is going to fail. This allows for an orderly and timely shutdown of the process to perform preventative maintenance, avoiding the need to repeat costly sample analyses. 7 figs., 2 tabs

Mössbauer spectroscopy.

Science.gov (United States)

Huynh, Boi Hanh

2011-01-01

Mössbauer spectroscopy has contributed significantly to the studies of Fe-containing proteins. Early applications yielded detailed electronic characterizations of hemeproteins, and thus enhanced our understanding of the chemical properties of this important class of proteins. The next stage of the applications was marked by major discoveries of several novel Fe clusters of complex structures, including the 8Fe7S P cluster and the mixed metal 1Mo7Fe M center in nitrogenase. Since early 1990 s, rapid kinetic techniques have been used to arrest enzymatic reactions for Mössbauer studies. A number of reaction intermediates were discovered and characterized, both spectroscopically and kinetically, providing unprecedented detailed molecular-level mechanistic information. This chapter gives a brief summary of the historical accounts and a concise description of some experimental and theoretical elements in Mössbauer spectroscopy that are essential for understanding Mössbauer spectra. Major biological applications are summarized at the end.

Study of thermal pre-treatment on anaerobic digestion of slaughterhouse waste by TGA-MS and FTIR spectroscopy.

Science.gov (United States)

Rodríguez-Abalde, Ángela; Gómez, Xiomar; Blanco, Daniel; Cuetos, María José; Fernández, Belén; Flotats, Xavier

2013-12-01

Thermogravimetric analysis coupled to mass spectrometry (TGA-MS) and Fourier-transform infrared spectroscopy (FTIR) were used to describe the effect of pasteurization as a hygienic pre-treatment of animal by-products over biogas production. Piggery and poultry meat wastes were used as substrates for assessing the anaerobic digestion under batch conditions at mesophilic range. Poultry waste was characterized by high protein and carbohydrate content, while piggery waste presented a major fraction of fat and lower carbohydrate content. Results from anaerobic digestion tests showed a lower methane yield for the pre-treated poultry sample. TGA-MS and FTIR spectroscopy allowed the qualitative identification of recalcitrant nitrogen-containing compounds in the pre-treated poultry sample, produced by Maillard reactions. In the case of piggery waste, the recalcitrant compounds were not detected and its biodegradability test reported higher methane yield and production rates. TGA-MS and FTIR spectroscopy were demonstrated to be useful tools for explaining results obtained by anaerobic biodegradability test and in describing the presence of inhibitory problems.

Call for papers for special issue of Journal of Molecular Spectroscopy focusing on "Frequency-comb spectroscopy"

Science.gov (United States)

Foltynowicz, Aleksandra; Picqué, Nathalie; Ye, Jun

2018-05-01

Frequency combs are becoming enabling tools for many applications in science and technology, beyond the original purpose of frequency metrology of simple atoms. The precisely evenly spaced narrow lines of a laser frequency comb inspire intriguing approaches to molecular spectroscopy, designed and implemented by a growing community of scientists. Frequency-comb spectroscopy advances the frontiers of molecular physics across the entire electro-magnetic spectrum. Used as frequency rulers, frequency combs enable absolute frequency measurements and precise line shape studies of molecular transitions, for e.g. tests of fundamental physics and improved determination of fundamental constants. As light sources interrogating the molecular samples, they dramatically improve the resolution, precision, sensitivity and acquisition time of broad spectral-bandwidth spectroscopy and open up new opportunities and applications at the leading edge of molecular spectroscopy and sensing.

Development of a highly efficient conversion electron Moessbauer spectroscopy (CEMS) detector for low temperature (xPb1-x)Te bilayers

International Nuclear Information System (INIS)

Pombo, Carlos Jose da Silva Matos

2006-01-01

The 57 Fe Moessbauer spectroscopy is a nuclear, non-destructive technique used for the investigation of structural, magnetic and hyperfine properties of several materials. It is a powerful tool in characterizing materials in physics, metallurgy, geology and biology field areas, especially magnetic materials, alloys and minerals containing Fe. Lately, the Conversion Electron Moessbauer Spectroscopy (CEMS) is widely used in making studies on ultra-thin magnetic films, as well as other nanostructured materials. In case of magnetic nanostructures, low temperature (LT) studies are especially important due to the possibility of dealing with superparamagnetic effects. In this work it was developed a CEMS measurement system for low temperatures ( R ) and an optical cryostat (Model SVT-400, Janis Research Co, USA), from which the project was originally conceived at the Applied Physics / Moessbauer spectroscopy Department from University of Duisburg-Essen, Germany. The LT-CEMS system was fully built, tested and successfully applied in a preliminary characterization of Fe/(Eu x Pb 1-x )Te(111) bilayers with use of a 15 angstrom, 57 Fe probe layer, with reasonable results at sample temperatures as low as 8 K. (author)

Characterization of the implantation damage in SiO2 with x-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Ajioka, T.; Ushio, S.

1986-01-01

X-ray photoelectron spectroscopy (XPS) has been applied to characterize the damage introduced into SiO 2 by ion implantation. By measuring the peak width of Si/sub 2p/ from SiO 2 which corresponds to perturbation of the SiO 2 network, good depth profiles of the damage have been obtained for implanted samples and subsequently annealed samples. The results show that the damage distributed more widely than that calculated from energy deposition and that the perturbation of the network is caused not only by radiation damage but also by the existence of impurities in the network. It has been found that the XPS method is effective to understand the atomic structure, and thus, electrical properties of SiO 2

Biomolecular EPR spectroscopy

CERN Document Server

Hagen, Wilfred Raymond

2008-01-01

Comprehensive, Up-to-Date Coverage of Spectroscopy Theory and its Applications to Biological SystemsAlthough a multitude of books have been published about spectroscopy, most of them only occasionally refer to biological systems and the specific problems of biomolecular EPR (bioEPR). Biomolecular EPR Spectroscopy provides a practical introduction to bioEPR and demonstrates how this remarkable tool allows researchers to delve into the structural, functional, and analytical analysis of paramagnetic molecules found in the biochemistry of all species on the planet. A Must-Have Reference in an Intrinsically Multidisciplinary FieldThis authoritative reference seamlessly covers all important bioEPR applications, including low-spin and high-spin metalloproteins, spin traps and spin lables, interaction between active sites, and redox systems. It is loaded with practical tricks as well as do's and don'ts that are based on the author's 30 years of experience in the field. The book also comes with an unprecedented set of...

XRD and 119Sn Moessbauer spectroscopy characterization of SnSe obtained from a simple chemical route

International Nuclear Information System (INIS)

Bernardes-Silva, Ana Claudia; Mesquita, A.F.; Moura de Neto, E.; Porto, A.O.; Ardisson, J.D.; Lima, G.M. de; Lameiras, F.S.

2005-01-01

Crystalline tin selenide semiconductor was synthesized by a chemical route. Selenium powder reacted with potassium boronhydride, giving a soluble selenium species potassium seleniumhydride. The reaction of potassium seleniumhydride with tin chloride produced crystalline tin selenide, which was characterized by X-ray diffraction, 119 Sn Moessbauer spectroscopy and scanning electronic microscopy. The material was thermally treated, in nitrogen flow, at 300 and 600 deg. C for 2 h and the particle size evolution was studied by X-ray diffraction. The X-ray diffraction and 119 Sn Moessbauer results showed that a mixture of tin oxides and orthorhombic tin selenide was obtained

Characterization of Glutaredoxin Fe-S Cluster-Binding Interactions Using Circular Dichroism Spectroscopy.

Science.gov (United States)

Albetel, Angela-Nadia; Outten, Caryn E

2018-01-01

Monothiol glutaredoxins (Grxs) with a conserved Cys-Gly-Phe-Ser (CGFS) active site are iron-sulfur (Fe-S) cluster-binding proteins that interact with a variety of partner proteins and perform crucial roles in iron metabolism including Fe-S cluster transfer, Fe-S cluster repair, and iron signaling. Various analytical and spectroscopic methods are currently being used to monitor and characterize glutaredoxin Fe-S cluster-dependent interactions at the molecular level. The electronic, magnetic, and vibrational properties of the protein-bound Fe-S cluster provide a convenient handle to probe the structure, function, and coordination chemistry of Grx complexes. However, some limitations arise from sample preparation requirements, complexity of individual techniques, or the necessity for combining multiple methods in order to achieve a complete investigation. In this chapter, we focus on the use of UV-visible circular dichroism spectroscopy as a fast and simple initial approach for investigating glutaredoxin Fe-S cluster-dependent interactions. © 2018 Elsevier Inc. All rights reserved.

Surface characterization of IM7/5260 composites by x-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Ohno, Satomi; Lee, Moon-Hwan; Lin, Kuen Y.; Ohuchi, Fumio S.

2001-01-01

Surfaces of high-performance carbon fiber/bismeleimide (BMI) composites (IM7/5260) have been characterized by x-ray photoelectron spectroscopy. An experimental technique to separately examine the chemical natures of the carbon fibers and BMI resin in the composite form was developed. This technique uses a flood gun to establish differential charging conditions on the BMI resin. The binding energies from the BMI resin were shifted by an amount of voltage applied to the flood gun, whereas those from the carbon fibers were uniquely determined due to their electrically conducting nature. By adding external bias voltage to the sample, the binding energies for conducting fibers were further shifted from those of the BMI resin, thereby separating the IM7 phase completely from the BMI phase in the binding energy scale, allowing independent measurement of the chemical changes associated with those peaks. Using this technique, the effects of thermal aging and surface plasma treatment on the IM7/5260 composite were studied

Characterization of the calcification of cardiac valve bioprostheses by environmental scanning electron microscopy and vibrational spectroscopy.

Science.gov (United States)

Delogne, Christophe; Lawford, Patricia V; Habesch, Steven M; Carolan, Vikki A

2007-10-01

Bioprosthetic heart valve tissue and associated calcification were studied in their natural state, using environmental scanning electron microscopy (ESEM). Energy dispersive X-ray micro-analysis, X-ray diffraction, Fourier-transform infrared and Raman spectroscopy were used to characterize the various calcific deposits observed with ESEM. The major elements present in calcified valves were also analyzed by inductively coupled plasma-optical emission spectroscopy. To better understand the precursor formation of the calcific deposits, results from the elemental analyses were statistically correlated. ESEM revealed the presence of four broad types of calcium phosphate crystal morphology. In addition, two main patterns of organization of calcific deposits were observed associated with the collagen fibres. Energy dispersive X-ray micro-analysis identified the crystals observed by ESEM as salts containing mainly calcium and phosphate with ratios from 1.340 (possibly octacalcium phosphate, which has a Ca/P ratio of 1.336) to 2.045 (possibly hydroxyapatite with incorporation of carbonate and metal ion contaminants, such as silicon and magnesium, in the crystal lattice). Raman and fourier-transform infrared spectroscopy also identified the presence of carbonate and the analyses showed spectral features very similar to a crystalline hydroxyapatite spectrum, also refuting the presence of precursor phases such as beta-tricalcium phosphate, octacalcium phosphate and dicalcium phosphate dihydrate. The results of this study raised the possibility of the presence of precursor phases associated with the early stages of calcification.

PIXE as a characterization technique in the cutting tool industry

International Nuclear Information System (INIS)

Freemantle, C.S.; Sacks, N.; Topic, M.; Pineda-Vargas, C.A.

2014-01-01

Two WC–Co powders have been analyzed using micro-PIXE to identify elemental concentration and distribution. A powder recycled primarily from used mining components and a powder produced exclusively from fresh raw materials was studied. Elemental mapping of major elements as well as impurities, within powder granule cross sections, was performed. Contaminants (e.g. Fe and Ni) from manufacturing processes, as well as trace impurities (e.g. Cr, Cl, Ca and S) from recycling were detected, quantified and compared. The extent of increased concentrations of impurities resulting from recycling were observed, demonstrating the potential for PIXE as a characterization tool for detecting trace elements in cemented carbides, allowing for future improvements in the manufacturing and recycling processes

PIXE as a characterization technique in the cutting tool industry

Energy Technology Data Exchange (ETDEWEB)

Freemantle, C.S., E-mail: chris@freemantle.co.za [School of Chemical and Metallurgical Engineering and DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, P/Bag 3, Wits 2050 (South Africa); Pilot Tools (Pty) (Ltd.), P.O. Box 27559, Benrose 2011 (South Africa); Sacks, N. [School of Chemical and Metallurgical Engineering and DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, P/Bag 3, Wits 2050 (South Africa); Topic, M. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, CPUT, Bellville (South Africa)

2014-01-01

Two WC–Co powders have been analyzed using micro-PIXE to identify elemental concentration and distribution. A powder recycled primarily from used mining components and a powder produced exclusively from fresh raw materials was studied. Elemental mapping of major elements as well as impurities, within powder granule cross sections, was performed. Contaminants (e.g. Fe and Ni) from manufacturing processes, as well as trace impurities (e.g. Cr, Cl, Ca and S) from recycling were detected, quantified and compared. The extent of increased concentrations of impurities resulting from recycling were observed, demonstrating the potential for PIXE as a characterization tool for detecting trace elements in cemented carbides, allowing for future improvements in the manufacturing and recycling processes.

Antibody-Unfolding and Metastable-State Binding in Force Spectroscopy and Recognition Imaging

Science.gov (United States)

Kaur, Parminder; Qiang-Fu; Fuhrmann, Alexander; Ros, Robert; Kutner, Linda Obenauer; Schneeweis, Lumelle A.; Navoa, Ryman; Steger, Kirby; Xie, Lei; Yonan, Christopher; Abraham, Ralph; Grace, Michael J.; Lindsay, Stuart

2011-01-01

Force spectroscopy and recognition imaging are important techniques for characterizing and mapping molecular interactions. In both cases, an antibody is pulled away from its target in times that are much less than the normal residence time of the antibody on its target. The distribution of pulling lengths in force spectroscopy shows the development of additional peaks at high loading rates, indicating that part of the antibody frequently unfolds. This propensity to unfold is reversible, indicating that exposure to high loading rates induces a structural transition to a metastable state. Weakened interactions of the antibody in this metastable state could account for reduced specificity in recognition imaging where the loading rates are always high. The much weaker interaction between the partially unfolded antibody and target, while still specific (as shown by control experiments), results in unbinding on millisecond timescales, giving rise to rapid switching noise in the recognition images. At the lower loading rates used in force spectroscopy, we still find discrepancies between the binding kinetics determined by force spectroscopy and those determined by surface plasmon resonance—possibly a consequence of the short tethers used in recognition imaging. Recognition imaging is nonetheless a powerful tool for interpreting complex atomic force microscopy images, so long as specificity is calibrated in situ, and not inferred from equilibrium binding kinetics. PMID:21190677

Characterization of ultrafine aluminum nanoparticles

International Nuclear Information System (INIS)

Sandstrom, Mary M.; Jorgensen, Betty S.; Mang, Joseph T.; Smith, Bettina L.; Son, Steven F.

2004-01-01

Aluminum nanopowders with particle sizes ranging from ∼25 nm to 80 nm were characterized by a variety of methods. We present and compare the results from common powder characterization techniques including transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), BET gas adsorption surface area analysis, thermogravimetric analysis (TGA), photon correlation spectroscopy (PCS), and low angle laser light scattering (LALLS). Aluminum nanoparticles consist of an aluminum core with an aluminum oxide coating. HRTEM measurements of both the particle diameter and oxide layer thickness tend to be larger than those obtained from BET and TGA. LALLS measurements show a large degree of particle agglomeration in solution; therefore, primary particle sizes could not be determined. Furthermore, results from small-angle scattering techniques (SAS), including small-angle neutron (SANS) and x-ray (SAXS) scattering are presented and show excellent agreement with the BET, TGA, and HRTEM. The suite of analytical techniques presented in this paper can be used as a powerful tool in the characterization of many types of nanosized powders.

Application of resonance ionisation spectroscopy in atomic physics

International Nuclear Information System (INIS)

Kluge, H.J.

1997-01-01

Resonance ionization spectroscopy (RIS) and resonance ionization mass spectroscopy (RIMS) techniques have proved to be a powerful tool in atomic spectroscopy and trace analysis. Detailed atomic spectroscopy can be performed on samples containing less than 10 12 atoms. This sensitivity is especially important for investigating atomic properties of transuranium elements. RIMS is especially suitable for ultra trace determination of long lived radioactive isotopes. The extremely low detection limits allow analysis of samples in the sub-femtogram regime. High elemental and isotopic selectivity can be obtained. To produce isobarically pure ion beams, a RIS based laser ion source can be used

Materials characterization by resonant ultrasonic spectroscopy method

International Nuclear Information System (INIS)

Cheong, Yong Moo; Jung, H.K.; Joo, Y.S.; Sim, C.M.

2001-01-01

A high temperature resonant ultrasound spectroscopy(RUS) was developed. The dynamic elastic constant of RPV weld, which has various different microstructure was determined by RUS. It was confirmed the RUS method is very sensitive to the microstructures of the material. RUS can be used to monitor the degradation of nuclear materials including neutron irradiation embrittlement through the measurement of dynamic elastic constants, elastic anisotropy, high temperature elastic constant and Q-factor

Soft X-ray emission spectroscopy used for the characterization of a-C and CN{sub x} thin films

Energy Technology Data Exchange (ETDEWEB)

Nepijko, S.A., E-mail: nepijko@uni-mainz.de [Institute of Physics, University of Mainz, Staudingerweg 7, 55128 Mainz (Germany); Chernenkaya, A. [Institute of Physics, University of Mainz, Staudingerweg 7, 55128 Mainz (Germany); Graduate School Materials Science in Mainz, Staudingerweg 9, 55128 Mainz (Germany); Medjanik, K.; Chernov, S.V. [Institute of Physics, University of Mainz, Staudingerweg 7, 55128 Mainz (Germany); Klimenkov, M. [Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Vlasenko, O.V. [Sumy State University, Rimsky-Korsakov str. 2, 40007 Sumy (Ukraine); Petrovskaya, S.S. [Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Krzhizhanovsky str. 3, 03142 Kiev (Ukraine); Odnodvorets, L.V. [Sumy State University, Rimsky-Korsakov str. 2, 40007 Sumy (Ukraine); Zaulichnyy, Ya.V. [National Technical University of Ukraine (KPI), Pobedy Av. 37, 03056 Kiev (Ukraine); Schönhense, G. [Institute of Physics, University of Mainz, Staudingerweg 7, 55128 Mainz (Germany)

2015-02-27

We present the results of a soft X-ray emission spectroscopy study of a-C and CN{sub x} films on a Si(100) substrate. Also for the characterization of the homogeneity in depth of these films electron energy loss spectroscopy measurements with localization better than 4 nm were carried out. In case of CN{sub x} films the highest diamond-like modification occurs in the region close to the Si(100) substrate. The film density decreases with increasing distance from the substrate and becomes almost constant in range of thicknesses more than ~ 2 nm. - Highlights: • CN{sub x} and a-C film densities decrease with the increase of thickness. • Density increases with the decrease of Si(100) substrate temperature at preparation. • Highest concentration of the diamond-like structure is in the substrate vicinity. • It reduces further from the substrate and stabilizes at thickness ≥ 2 nm.

Characterization of dissolved organic matter in fogwater by excitation-emission matrix fluorescence spectroscopy

Science.gov (United States)

Birdwell, J.E.; Valsaraj, K.T.

2010-01-01

Dissolved organic matter (DOM) present in fogwater samples collected in southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix fluorescence spectroscopy. The goal of the study was to illustrate the utility of fluorescence for obtaining information on the large fraction of organic carbon in fogwaters (typically >40% by weight) that defies characterization in terms of specific chemical compounds without the difficulty inherent in obtaining sufficient fogwater volume to isolate DOM for assessment using other spectroscopic and chemical analyses. Based on the findings of previous studies using other characterization methods, it was anticipated that the unidentified organic carbon fraction would have characteristic peaks associated with humic substances and fluorescent amino acids. Both humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices for the fogwater had similar values to those of soil and sediment porewater. Greater biological character was observed in samples with higher organic carbon concentrations. Fogwaters are shown to contain a mixture of terrestrially- and microbially-derived fluorescent organic material, which is expected to be derived from an array of different sources, such as suspended soil and dust particles, biogenic emissions and organic substances generated by atmospheric processes. The fluorescence results indicate that much of the unidentified organic carbon present in fogwater can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems, though it should be noted that fluorescent signatures representative of DOM produced by atmospheric processing of organic aerosols may be contributing to or masked by humic-like fluorophores. ?? 2010.

Electromagnetic field enhancement effects in group IV semiconductor nanowires. A Raman spectroscopy approach

Science.gov (United States)

Pura, J. L.; Anaya, J.; Souto, J.; Prieto, A. C.; Rodríguez, A.; Rodríguez, T.; Periwal, P.; Baron, T.; Jiménez, J.

2018-03-01

Semiconductor nanowires (NWs) are the building blocks of future nanoelectronic devices. Furthermore, their large refractive index and reduced dimension make them suitable for nanophotonics. The study of the interaction between nanowires and visible light reveals resonances that promise light absorption/scattering engineering for photonic applications. Micro-Raman spectroscopy has been used as a characterization tool for semiconductor nanowires. The light/nanowire interaction can be experimentally assessed through the micro-Raman spectra of individual nanowires. As compared to both metallic and dielectric nanowires, semiconductor nanowires add additional tools for photon engineering. In particular, one can grow heterostructured nanowires, both axial and radial, and also one could modulate the doping level and the surface condition among other factors than can affect the light/NW interaction. We present herein a study of the optical response of group IV semiconductor nanowires to visible photons. The study is experimentally carried out through micro-Raman spectroscopy of different group IV nanowires, both homogeneous and axially heterostructured (SiGe/Si). The results are analyzed in terms of the electromagnetic modelling of the light/nanowire interaction using finite element methods. The presence of axial heterostructures is shown to produce electromagnetic resonances promising new photon engineering capabilities of semiconductor nanowires.

Characterisation of Wear Resistant Boride Layers on a Tool Steel by Activity Controlled Pack Boronising

DEFF Research Database (Denmark)

Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

2015-01-01

The present work addresses the production and characterisation of iron boride layers by pack boronising of a Vanadis 6 tool steel. The boride layers were produced at 900°C for 2h using different pack compositions in order to obtain a single-phase boride layer. The layers were characterized...... by electron microscopy, glow discharge optical emission spectroscopy, X-ray diffraction, Vickers hardness tests and wear testing with a pin-on-disc tribometer. It was found that the type of boride phases (FeB and/or Fe2B) present in the treated layer can be controlled by changing the boron activity...... by pack boronising for all conditions as compared to the heat treated tool steel....

Raman spectroscopy as a tool for investigating lipid protein interactions

DEFF Research Database (Denmark)

Petersen, Frederic Nicolas Rønne; Helix Nielsen, Claus

2009-01-01

]) as well as improved technical equipment for signal capture (such as improved sensitivity of charge-coupled devices [CCDs]). Combined, these technological advances have brought Raman spectroscopy into a new era in which hitherto inaccessible or hardly accessible research areas now are becoming possible...

Near edge x-ray spectroscopy theory

International Nuclear Information System (INIS)

1994-01-01

We propose to develop a quantitative theory of x-ray spectroscopies in the near edge region, within about 100 eV of threshold. These spectroscopies include XAFS (X-ray absorption fine structure), photoelectron diffraction (PD), and diffraction anomalous fine structure (DAFS), all of which are important tools for structural studies using synchrotron radiation x-ray sources. Of primary importance in these studies are many-body effects, such as the photoelectron self-energy, and inelastic losses. A better understanding of these quantities is needed to obtain theories without adjustable parameters. We propose both analytical and numerical calculations, the latter based on our x-ray spectroscopy codes FEFF

Infrared spectroscopy: a potential tool in huanglongbing and citrus variegated chlorosis diagnosis.

Science.gov (United States)

Cardinali, Marcelo Camponez do Brasil; Villas Boas, Paulino Ribeiro; Milori, Débora Marcondes Bastos Pereira; Ferreira, Ednaldo José; França e Silva, Marina; Machado, Marcos Antonio; Bellete, Barbara Sayuri; da Silva, Maria Fatima das Graças Fernandes

2012-03-15

Huanglongbing (HLB) and citrus variegated chlorosis (CVC) are serious threats to citrus production and have caused considerable economic losses worldwide, especially in Brazil, which is one of the biggest citrus producers in the world. Neither disease has a cure nor an efficient means of control. They are also generally confused with each other in the field since they share similar initial symptoms, e.g., yellowing blotchy leaves. The most efficient tool for detecting these diseases is by polymerase chain reaction (PCR). However, PCR is expensive, is not high throughput, and is subject to cross reaction and contamination. In this report, a diagnostic method is proposed for detecting HLB and CVC diseases in leaves of sweet orange trees using attenuated total reflectance Fourier transform infrared spectroscopy and the induced classifier via partial least-squares regression. Four different leaf types were considered: healthy, CVC-symptomatic, HLB-symptomatic, and HLB-asymptomatic. The results show a success rate of 93.8% in correctly identifying these different leaf types. In order to understand which compounds are responsible for the spectral differences between the leaf types, samples of carbohydrates starch, sucrose, and glucose, flavonoids hesperidin and naringin, and coumarin umbelliferone were also analyzed. The concentration of these compounds in leaves may vary due to biotic stresses. Copyright © 2012 Elsevier B.V. All rights reserved.

Atomic column resolved electron energy-loss spectroscopy

International Nuclear Information System (INIS)

Duscher, G.; Pennycook, S.J.; Browning, N.D.

1998-01-01

Spatially resolved electron energy-loss spectroscopy (EELS) is rapidly developing into a unique and powerful tool to characterize internal interfaces. Because atomic column resolved Z-contrast imaging can be performed simultaneously with EELS in the scanning transmission electron microscope, this combination allows the atomic structure to be correlated with the electronic structure, and thus the local properties of interfaces or defects can be determined directly. However, the ability to characterize interfaces and defects at that level requires not only high spatial resolution but also the exact knowledge of the beam location, from where the spectrum is obtained. Here we discuss several examples progressing from cases where the limitation in spatial resolution is given by the microscopes or the nature of the sample, to one example of impurity atoms at a grain boundary, which show intensity and fine structure changes from atomic column to atomic column. Such data can be interpreted as changes in valence of the impurity, depending on its exact site in the boundary plane. Analysis ofthis nature is a valuable first step in understanding the microscopic structural, optical and electronic properties of materials. (orig.)

Laser induced breakdown spectroscopy for analysis and characterization of degradation pathologies of Roman glasses

International Nuclear Information System (INIS)

Palomar, T.; Oujja, M.; García-Heras, M.; Villegas, M.A.; Castillejo, M.

2013-01-01

The feasibility and possibilities of laser induced breakdown spectroscopy (LIBS) in the full study of non-destructible historic glasses have been explored in the present work. Thirteen Roman glass samples, including seven entire glass beads, from the ancient town of Augusta Emerita (SW Spain) were characterized by LIBS in combination with other conventional techniques, such as scanning electron microscopy/energy dispersive X-ray spectrometry, X-ray fluorescence and ultraviolet–visible spectrophotometry. LIBS stratigraphic analysis, carried out by the application of successive laser pulses on the same spot, has been mainly targeted at characterizing particular features of non-destructible historic glasses, such as bulk chemical composition, surface degradation pathologies (dealkalinization layers and deposits), chromophores, and opacifying elements. The obtained data demonstrate that LIBS can be a useful and alternative technique for spectroscopic studies of historical glasses, especially for those conserved under burial conditions and when it deals with studying non-destructible samples. - Highlights: • Determination of chromophores and opacifiers in non-destructible glass by LIBS • Manganese is determined as principal component of dark deposits. • Antimony appears in all decorations while lead is only present in yellow ones. • Stratigraphic analysis enables the identification of dealkalinization layers

Laser induced breakdown spectroscopy for analysis and characterization of degradation pathologies of Roman glasses

Energy Technology Data Exchange (ETDEWEB)

Palomar, T. [Instituto de Historia, Centro de Ciencias Humanas y Sociales, CSIC, C/Albasanz 26-28, 28037 Madrid (Spain); Oujja, M., E-mail: m.oujja@iqfr.csic.es [Instituto de Química Física Rocasolano, CSIC, C/Serrano 119, 28006 Madrid (Spain); García-Heras, M.; Villegas, M.A. [Instituto de Historia, Centro de Ciencias Humanas y Sociales, CSIC, C/Albasanz 26-28, 28037 Madrid (Spain); Castillejo, M. [Instituto de Química Física Rocasolano, CSIC, C/Serrano 119, 28006 Madrid (Spain)

2013-09-01

The feasibility and possibilities of laser induced breakdown spectroscopy (LIBS) in the full study of non-destructible historic glasses have been explored in the present work. Thirteen Roman glass samples, including seven entire glass beads, from the ancient town of Augusta Emerita (SW Spain) were characterized by LIBS in combination with other conventional techniques, such as scanning electron microscopy/energy dispersive X-ray spectrometry, X-ray fluorescence and ultraviolet–visible spectrophotometry. LIBS stratigraphic analysis, carried out by the application of successive laser pulses on the same spot, has been mainly targeted at characterizing particular features of non-destructible historic glasses, such as bulk chemical composition, surface degradation pathologies (dealkalinization layers and deposits), chromophores, and opacifying elements. The obtained data demonstrate that LIBS can be a useful and alternative technique for spectroscopic studies of historical glasses, especially for those conserved under burial conditions and when it deals with studying non-destructible samples. - Highlights: • Determination of chromophores and opacifiers in non-destructible glass by LIBS • Manganese is determined as principal component of dark deposits. • Antimony appears in all decorations while lead is only present in yellow ones. • Stratigraphic analysis enables the identification of dealkalinization layers.

Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

Science.gov (United States)

Varela, J. A.; Amado, J. M.; Tobar, M. J.; Mateo, M. P.; Yañez, A.; Nicolas, G.

2015-05-01

Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

Science.gov (United States)

Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

2015-04-01

The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

Electrical Impedance Spectroscopy for Electro-Mechanical Characterization of Conductive Fabrics

Directory of Open Access Journals (Sweden)

Tushar Kanti Bera

2014-06-01

Full Text Available When we use a conductive fabric as a pressure sensor, it is necessary to quantitatively understand its electromechanical property related with the applied pressure. We investigated electromechanical properties of three different conductive fabrics using the electrical impedance spectroscopy (EIS. We found that their electrical impedance spectra depend not only on the electrical properties of the conductive yarns, but also on their weaving structures. When we apply a mechanical tension or compression, there occur structural deformations in the conductive fabrics altering their apparent electrical impedance spectra. For a stretchable conductive fabric, the impedance magnitude increased or decreased under tension or compression, respectively. For an almost non-stretchable conductive fabric, both tension and compression resulted in decreased impedance values since the applied tension failed to elongate the fabric. To measure both tension and compression separately, it is desirable to use a stretchable conductive fabric. For any conductive fabric chosen as a pressure-sensing material, its resistivity under no loading conditions must be carefully chosen since it determines a measurable range of the impedance values subject to different amounts of loadings. We suggest the EIS method to characterize the electromechanical property of a conductive fabric in designing a thin and flexible fabric pressure sensor.

Metabolomic Characterization of Ovarian Epithelial Carcinomas by HRMAS-NMR Spectroscopy

Directory of Open Access Journals (Sweden)

D. Ben Sellem

2011-01-01

Full Text Available Objectives. The objectives of the present study are to determine if a metabolomic study by HRMAS-NMR can (i discriminate between different histological types of epithelial ovarian carcinomas and healthy ovarian tissue, (ii generate statistical models capable of classifying borderline tumors and (iii establish a potential relationship with patient's survival or response to chemotherapy. Methods. 36 human epithelial ovarian tumor biopsies and 3 healthy ovarian tissues were studied using 1H HRMAS NMR spectroscopy and multivariate statistical analysis. Results. The results presented in this study demonstrate that the three histological types of epithelial ovarian carcinomas present an effective metabolic pattern difference. Furthermore, a metabolic signature specific of serous (N-acetyl-aspartate and mucinous (N-acetyl-lysine carcinomas was found. The statistical models generated in this study are able to predict borderline tumors characterized by an intermediate metabolic pattern similar to the normal ovarian tissue. Finally and importantly, the statistical model of serous carcinomas provided good predictions of both patient's survival rates and the patient's response to chemotherapy. Conclusions. Despite the small number of samples used in this study, the results indicate that metabolomic analysis of intact tissues by HRMAS-NMR is a promising technique which might be applicable to the therapeutic management of patients.

Analysis and characterization of contamination in EUV reticles

Science.gov (United States)

Okoroanyanwu, Uzodinma; Dittmar, Kornelia; Fahr, Torsten; Wallow, Tom; La Fontaine, Bruno; Wood, Obert; Holfeld, Christian; Bubke, Karsten; Peters, Jan-Hendrik

2010-04-01

A host of complementary imaging techniques (Scanning Electron Microscopy), surface analytical technique (Auger Electron Spectroscopy, AES), chemical analytical and speciation techniques (Grazing Incidence Reflectance Fourier-Transform Infrared Spectroscopy, GIR-FTIR; and Raman spectroscopy) have been assessed for their sensitivity and effectiveness in analyzing contamination on three EUV reticles that were contaminated to varying degrees. The first reticle was contaminated as a result of its exposure experience on the SEMATECH EUV Micro Exposure Tool (MET) at Lawrence Berkeley National Laboratories, where it was exposed to up to 80 hours of EUV radiation. The second reticle was a full-field reticle, specifically designed to monitor molecular contamination, and exposed to greater than 1600J/cm2 of EUV radiation on the ASML Alpha Demo Tool (ADT) in Albany Nanotech in New York. The third reticle was intentionally contaminated with hydrocarbons in the Microscope for Mask Imaging and Contamination Studies (MIMICS) tool at the College of Nanoscale Sciences of State University of New York at Albany. The EUV reflectivities of some of these reticles were measured on the Advanced Light Source EUV Reflectomer at Lawrence Berkeley National Laboratories and PTB Bessy in Berlin, respectively. Analysis and characterization of thin film contaminants on the two EUV reticles exposed to varying degrees of EUV radiation in both MET and ADT confirm that the two most common contamination types are carbonization and surface oxidation, mostly on the exposed areas of the reticle, and with the MET being significantly more susceptible to carbon contamination than the ADT. While AES in both surface scanning and sputter mode is sensitive and efficient in analyzing thin contaminant films (of a few nanometers), GIRFTIR is sensitive to thick films (of order of a 100 nm or more on non-infra-red reflecting substrates), Raman spectroscopy is not compatible with analyzing such contaminants because of

Characterization of the intergrain and surface properties of Y1Ba2Cu3O7-x by Raman spectroscopy

International Nuclear Information System (INIS)

Erle, A.; Blumenroder, S.; Guntherodt, G.

1989-01-01

The intergrain region of polycrystalline YBa 2 Cu 3 O 7 - x has been identified by Raman spectroscopy as due to BaCuO 2 , which forms a coating of the grains. The oxygen concentration near the surface of single crystals (within ∼ 1000 Angstrom penetration depth of the light) is characterized by the intensity of the 590-cm - 1 oxygen vibration along the Cu-O chains

Application of a novel combination of near-infrared spectroscopy and a humidity-controlled 96-well plate to the characterization of the polymorphism of imidafenacin.

Science.gov (United States)

Uchida, Hiroshi; Yoshinaga, Tokuji; Mori, Hirotoshi; Otsuka, Makoto

2010-11-01

This study aimed to apply a currently available chemometric near-infrared spectroscopy technique to the characterization of the polymorphic properties of drug candidates. The technique requires only small quantities of samples and is therefore applicable to drugs in the early stages of development. The combination of near-infrared spectroscopy and a patented 96-well plate divided into 32 individual, humidity-controlled, three-well compartments was used in the characterization of a hygroscopic drug, imidafenacin, which has two polymorphs and one pseudo-polymorph. Characterization was also conducted with powder X-ray diffraction and thermal analysis. The results were compared with those from routinely used conventional analyses. Both the microanalysis and conventional analysis successfully characterised the substance (transformation and relative stability among the two polymorphs and a pseudo-polymorph) depending on the storage conditions. Near-infrared spectroscopic analyses utilizing a humidity-controlled 96-well plate required only small amounts of the sample for characterization under the various conditions of relative humidity. Near-infrared microanalysis can be applied to polymorphic studies of small quantities of a drug candidate. The results also suggest that the method will predict the behaviors of a hygroscopic candidate in solid pharmaceutical preparations at the early stages of drug development. © 2010 The Authors. JPP © 2010 Royal Pharmaceutical Society of Great Britain.

High-throughput quantitative biochemical characterization of algal biomass by NIR spectroscopy; multiple linear regression and multivariate linear regression analysis.

Science.gov (United States)

Laurens, L M L; Wolfrum, E J

2013-12-18

One of the challenges associated with microalgal biomass characterization and the comparison of microalgal strains and conversion processes is the rapid determination of the composition of algae. We have developed and applied a high-throughput screening technology based on near-infrared (NIR) spectroscopy for the rapid and accurate determination of algal biomass composition. We show that NIR spectroscopy can accurately predict the full composition using multivariate linear regression analysis of varying lipid, protein, and carbohydrate content of algal biomass samples from three strains. We also demonstrate a high quality of predictions of an independent validation set. A high-throughput 96-well configuration for spectroscopy gives equally good prediction relative to a ring-cup configuration, and thus, spectra can be obtained from as little as 10-20 mg of material. We found that lipids exhibit a dominant, distinct, and unique fingerprint in the NIR spectrum that allows for the use of single and multiple linear regression of respective wavelengths for the prediction of the biomass lipid content. This is not the case for carbohydrate and protein content, and thus, the use of multivariate statistical modeling approaches remains necessary.

Positron annihilation lifetime spectroscopy (PALS) as a characterization technique for nanostructured self-assembled amphiphile systems.

Science.gov (United States)

Dong, Aurelia W; Pascual-Izarra, Carlos; Pas, Steven J; Hill, Anita J; Boyd, Ben J; Drummond, Calum J

2009-01-08

Positron annihilation lifetime spectroscopy (PALS) has potential as a novel rapid characterization method for self-assembly amphiphile systems; however, a lack of systematic correlation of PALS parameters with structural attributes has limited its more widespread application. In this study, using the well-characterized phytantriol/water and the phytantriol/vitamin E acetate/water self-assembly amphiphile systems, the impact of systematic structural changes controlled by changes in composition and temperature on PALS parameters has been studied. The PALS parameters (orthopositronium (oPs) lifetime and intensity signatures) were shown to be sensitive to the molecular packing and mobility of the self-assembled lipid molecules in various lyotropic liquid crystalline phases, enabling differentiation between liquid crystalline structures. The oPs lifetime, related to the molecular packing and mobility, is correlated with rheological properties of the individual mesophases. The oPs lifetime links the lipid chain packing and mobility in the various mesophases to resultant macroscopic properties, such as permeability, which is critical for the use of these mesophase structures as diffusion-controlled release matrices for active liposoluble compounds.

Laser spectroscopy used in nuclear physics; La spectroscopie laser appliquee a la physique nucleaire

Energy Technology Data Exchange (ETDEWEB)

Le Blanc, F

2001-04-05

The study of nuclear shapes is a basic topic since it constitutes an excellent ground for testing and validating nuclear models. Measurements of the electron quadrupolar moment, of the nuclear charge radius and of the magnetic dipolar moment shed light on the nuclear deformation. Laser spectroscopy is a specific tool for such measurements, it is based on the interaction of the nucleus with the surrounding electron cloud (hyperfine structure), it is then an external approach of the shape of the nucleus whereas the classical nuclear spectroscopy ({alpha}, {beta} or {gamma}) gives information on the deformation from the inside of the nucleus. The author describes 2 techniques of laser spectroscopy: the colinear spectroscopy directly applied to a beam issued from an isotope separator and the resonant ionization spectroscopy linked with atom desorption that allows the study of particular nuclei. In order to illustrate both methods some effective measurements are presented: - the colinear spectroscopy has allowed the achievement of the complete description of the isomeric state (T = 31 years) of hafnium-178; - The experiment Complis has revealed an unexpected even-odd zigzag effect on very neutron-deficient platinum isotopes; and - the comparison of 2 isotopes of gold and platinum with their isomers has shown that the inversion of 2 levels of neutron, that was found out by nuclear spectroscopy, is in fact a consequence of a change in the nuclear shape. (A.C.)

1994 Fernald field characterization demonstration program data report

International Nuclear Information System (INIS)

Rautman, C.A.; Cromer, M.V.; Newman, G.C.; Beiso, D.A.

1995-12-01

The 1994 Fernald field characterization demonstration program, hosted by Fernald Environmental Management Project, was established to investigate technologies that are applicable to the characterization and remediation of soils contaminated with uranium. An important part of this effort was evaluating field-screening tools potentially capable of acquiring high-resolution information on uranium contamination distribution in surface soils. Further-more, the information needed to be obtained in a cost- and time-efficient manner. Seven advanced field-screening technologies were demonstrated at a uranium-contaminated site at Fernald, located 29 kilometers northwest of Cincinnati, Ohio. The seven technologies tested were: (1) alpha-track detectors, (2) a high-energy beta scintillometer, (3) electret ionization chambers, (4) and (5) two variants of gamma-ray spectrometry, (6) laser ablation-inductively coupled plasma-atomic emission spectroscopy, and (7) long-range alpha detection. The goals of this field demonstration were to evaluate the capabilities of the detectors and to demonstrate their utility within the US Department of Energy's Environmental Restoration Program. Identical field studies were conducted using four industry-standard characterization tools: (1) a sodium-iodide scintillometer, (2) a low-energy FIDLER scintillometer, (3) a field-portable x-ray fluorescence detector, and (4) standard soil sampling coupled with laboratory analysis. Another important aspect of this program was the application of a cost/risk decision model to guide characterization of the site. This document is a compilation of raw data submitted by the technologies and converted total uranium data from the 1994 Fernald field characterization demonstration

Laser-Induced Breakdown Spectroscopy (LIBS) for Monitoring the Formation of Hydroxyapatite Porous Layers

OpenAIRE

Sola, Daniel; Paulés, Daniel; Grima, Lorena; Anzano, Jesús

2017-01-01

Laser-induced breakdown spectroscopy (LIBS) is applied to characterize the formation of porous hydroxyapatite layers on the surface of 0.8CaSiO3-0.2Ca3(PO4)2 biocompatible eutectic glass immersed in simulated body fluid (SBF). Compositional and structural characterization analyses were also conducted by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and micro-Raman spectroscopy.

Detection of carotenoids present in blood of various animal species using Raman spectroscopy

Science.gov (United States)

Liaqat, Maryam; Younus, Ayesha; Saleem, Muhammad; Rashid, Imaad; Yaseen, Maria; Jabeen, Saher

Raman spectroscopy is simple stable powerful diagnostic tool for body fluids, tissues and other biomolecules. Human blood possesses different kind of carotenoids that play a key role for protecting the cells from damaging by different viral and bacterial diseases. Carotenoids are antioxidative components which are capable to overcome the attack of different free radicals and reactive oxygen species. Carotenoids are not prepared by human body, therefore it is recommended to eat carotenoids enrich vegetable foods. No standard data is available on the concentration of useful carotenoids component in non-vegetable consumed items. In present research work, Raman spectroscopy is used to compare various blood components like plasma, serum, carotenoids present in blood of different animal species like goat, sheep, cow and buffalo consumed by human. Especially beta carotene is investigated. The Raman shift ranges from 600-1700 cm-1 for samples. Different characteristic peaks of the blood components are found which are not characterized before in animal samples. Doctrate Student in Photonics Deparatment of Electrical Engineering.

Modulated Raman Spectroscopy for Enhanced Cancer Diagnosis at the Cellular Level

Science.gov (United States)

De Luca, Anna Chiara; Dholakia, Kishan; Mazilu, Michael

2015-01-01

Raman spectroscopy is emerging as a promising and novel biophotonics tool for non-invasive, real-time diagnosis of tissue and cell abnormalities. However, the presence of a strong fluorescence background is a key issue that can detract from the use of Raman spectroscopy in routine clinical care. The review summarizes the state-of-the-art methods to remove the fluorescence background and explores recent achievements to address this issue obtained with modulated Raman spectroscopy. This innovative approach can be used to extract the Raman spectral component from the fluorescence background and improve the quality of the Raman signal. We describe the potential of modulated Raman spectroscopy as a rapid, inexpensive and accurate clinical tool to detect the presence of bladder cancer cells. Finally, in a broader context, we show how this approach can greatly enhance the sensitivity of integrated Raman spectroscopy and microfluidic systems, opening new prospects for portable higher throughput Raman cell sorting. PMID:26110401

Spectroscopic Characterization of Omeprazole and Its Salts

Directory of Open Access Journals (Sweden)

Tomislav Vrbanec

2017-01-01

Full Text Available During drug development, it is important to have a suitable crystalline form of the active pharmaceutical ingredient (API. Mostly, the basic options originate in the form of free base, acid, or salt. Substances that are stable only within a certain pH range are a challenge for the formulation. For the prazoles, which are known to be sensitive to degradation in an acid environment, the formulation is stabilized with alkaline additives or with the application of API formulated as basic salts. Therefore, preparation and characterization of basic salts are needed to monitor any possible salinization of free molecules. We synthesized salts of omeprazole from the group of alkali metals (Li, Na, and K and alkaline earth metals (Mg, Ca. The purpose of the presented work is to demonstrate the applicability of vibrational spectroscopy to discriminate between the OMP and OMP-salt molecules. For this reason, the physicochemical properties of 5 salts were probed using infrared and Raman spectroscopy, NMR, TG, DSC, and theoretical calculation of vibrational frequencies. We found out that vibrational spectroscopy serves as an applicable spectroscopic tool which enables an accurate, quick, and nondestructive way to determine the characteristic of OMP and its salts.

Detecting Damage in Composite Material Using Nonlinear Elastic Wave Spectroscopy Methods

Science.gov (United States)

Meo, Michele; Polimeno, Umberto; Zumpano, Giuseppe

2008-05-01

Modern aerospace structures make increasing use of fibre reinforced plastic composites, due to their high specific mechanical properties. However, due to their brittleness, low velocity impact can cause delaminations beneath the surface, while the surface may appear to be undamaged upon visual inspection. Such damage is called barely visible impact damage (BVID). Such internal damages lead to significant reduction in local strengths and ultimately could lead to catastrophic failures. It is therefore important to detect and monitor damages in high loaded composite components to receive an early warning for a well timed maintenance of the aircraft. Non-linear ultrasonic spectroscopy methods are promising damage detection and material characterization tools. In this paper, two different non-linear elastic wave spectroscopy (NEWS) methods are presented: single mode nonlinear resonance ultrasound (NRUS) and nonlinear wave modulation technique (NWMS). The NEWS methods were applied to detect delamination damage due to low velocity impact (<12 J) on various composite plates. The results showed that the proposed methodology appear to be highly sensitive to the presence of damage with very promising future NDT and structural health monitoring applications.

Moessbauer Spectroscopy in the Characterization of waste product used like fertilizer in soil. Some Applications

International Nuclear Information System (INIS)

Furet, N. R.; Orihuela, D. L.; Hernandez

2007-01-01

At the present time, the use of industrial solid wastes is an important task, because a great effort that have been carried out to preserve the environmental and to obtain the high technologies. In this work, a characterization of a industrial waste product, on base of the monohydrous iron sulphate (FeSO 4 .1H 2 O) with a 15% approximately of free sulphuric acid, used like improvement of soil was carried out by Mossabuer spectroscopy. This waste product was used in a series of the experiences in parcels (where peaches, (Prunus persica), strawberries are cultivated) in the zone of Cartaya (Huelva, Spain). The characterisation of soil from the parcel before application of this product was carried out in order to analyse and compare with the final results by using the methods of the Moessbauer spectroscopy. High contents of Fe, S, and Zn at the studied product are observed . This elements are very important for plants. The pH in soil and Fe, Mn, and Zn contents in soil and leaf were determined. The knowledge of the main chemical-structural properties of this product, used like improvement of soil, will permit the study of the influence to) on the soil properly, b) on the peach leaves and c) on the foodstuff fruit. (Author)

Fully Automated Lipid Pool Detection Using Near Infrared Spectroscopy

Directory of Open Access Journals (Sweden)

Elżbieta Pociask

2016-01-01

Full Text Available Background. Detecting and identifying vulnerable plaque, which is prone to rupture, is still a challenge for cardiologist. Such lipid core-containing plaque is still not identifiable by everyday angiography, thus triggering the need to develop a new tool where NIRS-IVUS can visualize plaque characterization in terms of its chemical and morphologic characteristic. The new tool can lead to the development of new methods of interpreting the newly obtained data. In this study, the algorithm to fully automated lipid pool detection on NIRS images is proposed. Method. Designed algorithm is divided into four stages: preprocessing (image enhancement, segmentation of artifacts, detection of lipid areas, and calculation of Lipid Core Burden Index. Results. A total of 31 NIRS chemograms were analyzed by two methods. The metrics, total LCBI, maximal LCBI in 4 mm blocks, and maximal LCBI in 2 mm blocks, were calculated to compare presented algorithm with commercial available system. Both intraclass correlation (ICC and Bland-Altman plots showed good agreement and correlation between used methods. Conclusions. Proposed algorithm is fully automated lipid pool detection on near infrared spectroscopy images. It is a tool developed for offline data analysis, which could be easily augmented for newer functions and projects.

Dynamic light scattering and X-ray photoelectron spectroscopy characterization of PEGylated polymer nanocarriers: internal structure and surface properties.

Science.gov (United States)

Celasco, Edvige; Valente, Ilaria; Marchisio, Daniele L; Barresi, Antonello A

2014-07-22

In this work, nanospheres and nanocapsules are precipitated in confined impinging jet mixers through solvent displacement and characterized. Acetone and water are used as the solvent and antisolvent, respectively, together with polymethoxypolyethylene glycol cyanoacrylate-co-hexadecylcyanoacrylate and Miglyol as the copolymer and oil, respectively. Characterization is performed with dynamic light scattering, with electrophoretic measurements, and for the first time with X-ray photoelectron spectroscopy. Results show that the presence of polyethylene glycol chains seems to be more pronounced on the surface of nanospheres than on that of nanocapsules. The thickness of the copolymer layer in nanocapsules ranges from 1 to 10 nm, depending on the value of the oil:copolymer mass ratio. Fast dilution is confirmed to have a positive effect in suppressing aggregation but can induce further copolymer precipitation.

Characterization of Metalloproteins and Biomaterials by X-ray Absorption Spectroscopy and X-ray Diffraction

DEFF Research Database (Denmark)

Frankær, Christian Grundahl

This thesis presents thework on combining complementary X-rays techniques for studying the structures of proteins and other biomaterials, and consists of three different projects: (i) Characterization of protein powders with X-ray powder diffraction (XRPD). (ii) The combination of X-ray...... crystallography and X-ray absorption spectroscopy (XAS) applied to studying different hexameric insulin conformations. (iii) The structures of polymorphs of strontium ranelate and the distribution of strontium in bone tissue. A procedure for fast identification and verification of protein powders using XRPD...... was correction for disordered bulk-solvent, but also correction for background and optimization of unit cell parameters have to be taken into account. A sample holder was designed for collecting powder diffraction data on a standard laboratory X-ray powder diffractometer. The background was reduced by use...

Structural characterization of H plasma-doped ZnO single crystals by positron annihilation spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Anwand, Wolfgang; Brauer, Gerhard; Cowan, Thomas E. [Institut fuer Strahlenphysik, Forschungszentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Grambole, Dieter; Skorupa, Wolfgang [Institut fuer Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Cizek, Jakub; Kuriplach, Jan; Prochazka, Ivan [Department of Low Temperature Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Egger, Werner; Sperr, Peter [Institut fuer Angewandte Physik und Messtechnik, Fakultaet fuer Luft- und Raumfahrttechnik, Universitaet der Bundeswehr, Heisenbergweg 39, 85579 Neubiberg (Germany)

2010-11-15

Nominally undoped, hydrothermally grown ZnO single crystals have been investigated before and after exposure to remote H plasma. Structural characterizations have been made by various positron annihilation spectroscopies (continuous and pulsed slow positron beams, conventional lifetime). The content of bound hydrogen (H-b) before and after the remote H plasma treatment at the polished side of the crystals was determined at depths of 100 and 600 nm, respectively, using nuclear reaction analysis. At a depth of 100 nm, H-b increased from (11.8{+-}2.5) to (48.7{+-}7.6) x 10{sup 19} cm{sup -3} after remote H plasma treatment, whereas at 600 nm no change in H-b was observed. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

X-ray diffraction, IR spectroscopy and thermal characterization of partially hydrolyzed guar gum.

Science.gov (United States)

Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

2012-05-01

Guar gum was hydrolyzed using cellulase from Aspergillus niger at 5.6 pH and 50°C temperature. Hydrolyzed guar gum sample was characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, dilute solution viscometry and rotational viscometry. Viscometry analysis of native guar gum showed a molecular weight of 889742.06, whereas, after enzymatic hydrolysis, the resultant product had a molecular weight of 7936.5. IR spectral analysis suggests that after enzymatic hydrolysis of guar gum there was no major transformation of functional group. Thermal analysis revealed no major change in thermal behavior of hydrolyzed guar gum. It was shown that partial hydrolysis of guar gum could be achieved by inexpensive and food grade cellulase (Aspergillus niger) having commercial importance and utilization as a functional soluble dietary fiber for food industry. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterization of Inclusions in Evolution of Sodium Sulfate Using Terahertz Time-domain Spectroscopy.

Science.gov (United States)

Bao, Rima; Wu, Zhikui; Li, Hao; Wang, Fang; Miao, Xinyang; Feng, Chengjing

2017-01-01

The study of fluid inclusion is one of the important means to understanding the evolution of mineral crystals, and can therefore provide original information of mineral evolution. In the process of evolution, outside factors such as temperature and pressure, directly affect the number and size of inclusions, and thus are related to the properties of crystals. In this paper, terahertz time-domain spectroscopy (THz-TDS) was used to detect sodium sulfate crystals with different growth temperatures, and absorption coefficient spectra of the samples were obtained. It is suggested that the evolution of sodium sulfate could be divided into two stages, and 80°C was the turning point. X-ray diffraction (XRD) and polarizing microscopy were used to support this conclusion. The research showed that THz-TDS could characterize the evolution of mineral crystals, and it had a unique advantage in terms of crystal evolution.

Cluster tool for in situ processing and comprehensive characteriza tion of thin films at high temperatures.

Science.gov (United States)

Wenisch, Robert; Lungwitz, Frank; Hanf, Daniel; Heller, Rene; Zscharschuch, Jens; Hübner, René; von Borany, Johannes; Abrasonis, Gintautas; Gemming, Sibylle; Escobar-Galindo, Ramon; Krause, Matthias

2018-05-31

A new cluster tool for in situ real-time processing and depth-resolved compositional, structural and optical characterization of thin films at temperatures from -100 to 800 °C is described. The implemented techniques comprise magnetron sputtering, ion irradiation, Rutherford backscattering spectrometry, Raman spectroscopy and spectroscopic ellipsometry. The capability of the cluster tool is demonstrated for a layer stack MgO/ amorphous Si (~60 nm)/ Ag (~30 nm), deposited at room temperature and crystallized with partial layer exchange by heating up to 650°C. Its initial and final composition, stacking order and structure were monitored in situ in real time and a reaction progress was defined as a function of time and temperature.

Structural characterization of ammonium uranate by infrared spectroscopy

International Nuclear Information System (INIS)

Rodriguez S, A.

1994-01-01

Infrared spectroscopy have been used to investigate the chemical composition of some ammonium uranates. In this study, I have attempted to establish the interrelationship between the structure of the products, the character of their infrared spectra and x-ray diffraction data capable of consistent interpretation in terms of defining the compounds. (Author)

Electron capture and energy-gain spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Taulbjerg, K.

1989-01-01

The applicability of translation energy spectroscopy as a tool to determine individual reaction cross sections in atomic collisions is analyzed with special emphasis on the electron capture process in highly charged ion collisions. A condition is derived to separate between higher collision energies where translation energy spectroscopy is problem free and lower energies where strong overlap of individual spectra features prohibits an analysis of the total translation energy spectrum by means of a simple deconvolution procedure. 8 refs., 6 figs.

Conversion electron spectroscopy in transfermium nuclei

International Nuclear Information System (INIS)

Herzberg, R.D.

2003-01-01

Conversion electron spectroscopy is an essential tool for the spectroscopy of heavy deformed nuclei. The conversion electron spectrometer SACRED has been used in conjunction with the gas-filled recoil separator RITU to study conversion electron cascades in 254 No. The spectra reveal the ground state rotational bands down to low spin. A detailed analysis of the background seen for 254 No shows that approximately 40% of the decay path goes via excited high K bands which may be built on an isomer. (orig.)

Application of MCD spectroscopy and TD-DFT to endohedral metallofullerenes for characterization of their electronic transitions.

Science.gov (United States)

Yamada, Michio; Slanina, Zdenek; Mizorogi, Naomi; Muranaka, Atsuya; Maeda, Yutaka; Nagase, Shigeru; Akasaka, Takeshi; Kobayashi, Nagao

2013-03-14

We describe, for the first time, the application of magnetic circular dichroism (MCD) spectroscopy and time-dependent density functional theory (TD-DFT) calculations using B3LYP and M06-2X functionals to characterize the electronic transitions of endohedral metallofullerenes (EMFs). Results revealed that the electronic transitions of La@C(2v)-C(82), La(2)@I(h)-C(80), and Sc(3)N@I(h)-C(80) can be assigned using these techniques. Particularly, a difference in the electronic transitions between La(2)@I(h)-C(80) and Sc(3)N@I(h)-C(80), which is invisible in absorption spectra, was observed clearly in MCD spectra. The observed MCD bands agree well with the oscillator strengths calculated using the B3LYP functional. In addition, the MCD bands of La(2)@I(h)-C(80) were altered upon [5,6]-addition, demonstrating that the MCD spectroscopy is sensitive to chemical functionalization of EMFs, and that it is therefore powerful to distinguish [5,6]-adducts from pristine La(2)@I(h)-C(80), although no marked difference exists in their absorption spectra.

Atomic Auger spectroscopy: Historical perspective and recent highlights

International Nuclear Information System (INIS)

Mehlhorn, W.

2000-01-01

The non-radiating decay of an inner-shell ionized atom by the emission of an electron was discovered by Pierre Auger in cloud-chamber experiments in the years 1923 to 1926. The first spectroscopic investigation of Auger electrons was performed by Robinson and Cassie in 1926, marking the birth date of Auger spectroscopy. The following seven decades of Auger spectroscopy will be divided into three periods. In the first period (1926-1960) Auger spectroscopy was mainly connected with β-ray spectroscopy where inner-shell ionization of atoms in the solid state was caused either by γ-conversion or by electron capture. The second period (beginning in 1960) is characterized by the external excitation of gas-phase or free metallic atoms, opening Auger spectroscopy to electron energies in the range of few eV to few keV. The third period (beginning in 1977/78) is characterized by the use of synchrotron radiation with its outstanding properties of tunability, polarization and narrow-band high intensity for the excitation and ionization of inner-shell electrons. Finally, two recent highlights of Auger spectroscopy, the interference between photo- and Auger electron with equal energies and an 'almost' complete experiment for Auger decay, will be presented

In-Situ Raman Characterization of SOFC Anodes

KAUST Repository

Maher, Robert C.; Offer, Gregory; Brandon, Nigel P.; Cohen, Lesley F.

2012-01-01

Solid oxide fuel cells (SOFCs) have many advantages when compared to other fuel cell technologies, particularly for distributed stationary applications. As a consequence they are becoming ever more economically competitive with incumbent energy solutions. However, as with all technologies, improvements in durability, efficiency and cost is required before they become feasible alternatives. Such improvements are enabled through improved understanding of the critical material interactions occurring during operation. Raman spectroscopy is a noninvasive and non-destructive optical characterization tool which is ideally suited to the study of these critical chemical processes occurring within operational SOFCs. In this paper we will discuss advantages of using Raman characterization for understanding these important chemical processes occurring within SOFCs. We will present the specific examples of the type of measurement possible and discuss the direction of future research. © 2012 Materials Research Society.

Laser-Induced Breakdown Spectroscopy (LIBS for Monitoring the Formation of Hydroxyapatite Porous Layers

Directory of Open Access Journals (Sweden)

Daniel Sola

2017-12-01

Full Text Available Laser-induced breakdown spectroscopy (LIBS is applied to characterize the formation of porous hydroxyapatite layers on the surface of 0.8CaSiO3-0.2Ca3(PO42 biocompatible eutectic glass immersed in simulated body fluid (SBF. Compositional and structural characterization analyses were also conducted by field emission scanning electron microscopy (FESEM, energy dispersive X-ray spectroscopy (EDX, and micro-Raman spectroscopy.

U(IV) fluorescence spectroscopy. A new speciation tool

Energy Technology Data Exchange (ETDEWEB)

Lehmann, Susanne; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

2017-06-01

We combined absorption and fluorescence spectroscopy to study the speciation of U(IV) in solution in concentrations down to 10{sup -6} M uranium. With our time-resolved laser-induced fluorescence setup we could determine the fluorescence decay time of U(IV) in perchloric as well as in chloric acid with 2.6 ± 0.3 ns at room temperature and 148.4 ± 6.5 ns at liquid nitrogen temperature. For the U(IV) sulfate system, we observed a bathochromic shift and a peak shape modification in the fluorescence spectra with increasing sulfate concentration in solution. Thus, the potential of U(IV) fluorescence for speciation analysis could be proven.

In situ monitoring of cocrystals in formulation development using low-frequency Raman spectroscopy.

Science.gov (United States)

Otaki, Takashi; Tanabe, Yuta; Kojima, Takashi; Miura, Masaru; Ikeda, Yukihiro; Koide, Tatsuo; Fukami, Toshiro

2018-05-05

In recent years, to guarantee a quality-by-design approach to the development of pharmaceutical products, it is important to identify properties of raw materials and excipients in order to determine critical process parameters and critical quality attributes. Feedback obtained from real-time analyses using various process analytical technology (PAT) tools has been actively investigated. In this study, in situ monitoring using low-frequency (LF) Raman spectroscopy (10-200 cm -1 ), which may have higher discriminative ability among polymorphs than near-infrared spectroscopy and conventional Raman spectroscopy (200-1800 cm -1 ), was investigated as a possible application to PAT. This is because LF-Raman spectroscopy obtains information about intermolecular and/or lattice vibrations in the solid state. The monitoring results obtained from Furosemide/Nicotinamide cocrystal indicate that LF-Raman spectroscopy is applicable to in situ monitoring of suspension and fluidized bed granulation processes, and is an effective technique as a PAT tool to detect the conversion risk of cocrystals. LF-Raman spectroscopy is also used as a PAT tool to monitor reactions, crystallizations, and manufacturing processes of drug substances and products. In addition, a sequence of conversion behaviors of Furosemide/Nicotinamide cocrystals was determined by performing in situ monitoring for the first time. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of Ge-nanocrystal films with photoelectron spectroscopy

International Nuclear Information System (INIS)

Bostedt, C.; Buuren, T. van; Willey, T.M.; Nelson, A.J.; Franco, N.; Moeller, T.; Terminello, L.J.

2003-01-01

The Ge 3d core-levels of germanium nanocrystal films have been investigated by means of photoelectron spectroscopy. The experiments indicate bulk-like coordinated atoms in the nanocrystals and suggest structured disorder on the nanoparticle surface. The results underline the importance of the surface on the overall electronic structure of this class of nanostructured materials

NMR spectroscopy: a tool for conformational analysis

International Nuclear Information System (INIS)

Tormena, Claudio F.; Cormanich, Rodrigo A.; Rittner, Roberto; Freitas, Matheus P.

2011-01-01

The present review deals with the application of NMR data to the conformational analysis of simple organic compounds, together with other experimental methods like infrared spectroscopy and with theoretical calculations. Each sub-section describes the results for a group of compounds which belong to a given organic function like ketones, esters, etc. Studies of a single compound, even of special relevance, were excluded since the main goal of this review is to compare the results for a given function, where different substituents were used or small structural changes were introduced in the substrate, in an attempt to disclose their effects in the conformational equilibrium. Moreover, the huge amount of data available in the literature, on this research field, imposed some limitations which will be detailed in the Introduction, but it can be reminded in advance that these limitations include mostly the period when these results were published. (author)

Fourier Transform Infrared Spectroscopy as a Tool in Analysis of Proteus mirabilis Endotoxins.

Science.gov (United States)

Żarnowiec, Paulina; Czerwonka, Grzegorz; Kaca, Wiesław

2017-01-01

Fourier transform infrared spectroscopy (FT-IR) was used to scan whole bacterial cells as well as lipopolysaccharides (LPSs, endotoxins) isolated from them. Proteus mirabilis cells, with chemically defined LPSs, served as a model for the ATR FT-IR method. The paper focuses on three steps of infrared spectroscopy: (1) sample preparation, (2) IR scanning, and (3) multivariate analysis of IR data (principal component analysis, PCA).

Pink berry grape (Vitis vinifera L.) characterization: Reflectance spectroscopy, HPLC and molecular markers.

Science.gov (United States)

Rustioni, Laura; De Lorenzis, Gabriella; Hârţa, Monica; Failla, Osvaldo

2016-01-01

Color has a fundamental role for the qualitative evaluation and cultivar characterization of fruits. In grape, a normally functional pigment biosynthesis leads to the accumulation of a high quantity of anthocyanins. In this work, 28 Vitis vinifera L. cultivars accumulating low anthocyanins in berries were studied to characterize the biosynthetic dysfunctions in both a phenotypic and genotypic point of view. Reflectance spectroscopy, HPLC profiles and molecular markers related to VvMybA1 and VvMybA2 genes allowed a detailed description of the pigment-related characteristics of these cultivars. Data were consistent concerning the heterozygosity of the non-functional allele in both investigated genes, resulting in a low colored phenotype as described by reflectance. However, the variability in berry colour among our samples was not fully explained by MybA locus, probably due to specific interferences among the biosynthetic pathways, as suggested by the anthocyanin profile variations detected among our samples. The results presented in this work confirmed the importance of the genetic background: grapes accumulating high levels of cyanidin-3-O-glucosides (di-substituted anthocyanin) are generally originated by white cultivar retro-mutations and they seem to preserve the anomalies in the flavonoid hydroxylases enzymes which negatively affect the synthesis of tri-substituted anthocyanins. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Linear and Nonlinear Molecular Spectroscopy with Laser Frequency Combs

Science.gov (United States)

Picque, Nathalie

2013-06-01

The regular pulse train of a mode-locked femtosecond laser can give rise to a comb spectrum of millions of laser modes with a spacing precisely equal to the pulse repetition frequency. Laser frequency combs were conceived a decade ago as tools for the precision spectroscopy of atomic hydrogen. They are now becoming enabling tools for an increasing number of applications, including molecular spectroscopy. Recent experiments of multi-heterodyne frequency comb Fourier transform spectroscopy (also called dual-comb spectroscopy) have demonstrated that the precisely spaced spectral lines of a laser frequency comb can be harnessed for new techniques of linear absorption spectroscopy. The first proof-of-principle experiments have demonstrated a very exciting potential of dual-comb spectroscopy without moving parts for ultra-rapid and ultra-sensitive recording of complex broad spectral bandwidth molecular spectra. Compared to conventional Michelson-based Fourier transform spectroscopy, recording times could be shortened from seconds to microseconds, with intriguing prospects for spectroscopy of short lived transient species. The resolution improves proportionally to the measurement time. Therefore longer recordings allow high resolution spectroscopy of molecules with extreme precision, since the absolute frequency of each laser comb line can be known with the accuracy of an atomic clock. Moreover, since laser frequency combs involve intense ultrashort laser pulses, nonlinear interactions can be harnessed. Broad spectral bandwidth ultra-rapid nonlinear molecular spectroscopy and imaging with two laser frequency combs is demonstrated with coherent Raman effects and two-photon excitation. Real-time multiplex accessing of hyperspectral images may dramatically expand the range of applications of nonlinear microscopy. B. Bernhardt et al., Nature Photonics 4, 55-57 (2010); A. Schliesser et al. Nature Photonics 6, 440-449 (2012); T. Ideguchi et al. arXiv:1201.4177 (2012) T

Time-resolved photoelectron spectroscopy using synchrotron radiation time structure

International Nuclear Information System (INIS)

Bergeard, N.; Silly, M.G.; Chauvet, C.; Guzzo, M.; Ricaud, J.P.; Izquierdo, M.; Sirotti, F.; Krizmancic, D.; Guzzo, M.; Stebel, L.; Pittana, P.; Sergo, R.; Cautero, G.; Dufour, G.; Rochet, F.

2011-01-01

Synchrotron radiation time structure is becoming a common tool for studying dynamic properties of materials. The main limitation is often the wide time domain the user would like to access with pump-probe experiments. In order to perform photoelectron spectroscopy experiments over time scales from milliseconds to picoseconds it is mandatory to measure the time at which each measured photoelectron was created. For this reason the usual CCD camera based two-dimensional detection of electron energy analyzers has been replaced by a new delay-line detector adapted to the time structure of the SOLEIL synchrotron radiation source. The new two-dimensional delay-line detector has a time resolution of 5 ns and was installed on a Scienta SES 2002 electron energy analyzer. The first application has been to characterize the time of flight of the photo emitted electrons as a function of their kinetic energy and the selected pass energy. By repeating the experiment as a function of the available pass energy and of the kinetic energy, a complete characterization of the analyzer behaviour in the time domain has been obtained. Even for kinetic energies as low as 10 eV at 2 eV pass energy, the time spread of the detected electrons is lower than 140 ns. These results and the time structure of the SOLEIL filling modes assure the possibility of performing pump-probe photoelectron spectroscopy experiments with the time resolution given by the SOLEIL pulse width, the best performance of the beamline and of the experimental station. (authors)

Characterizing the Solvated Structure of Photoexcited [Os(terpy2]2+ with X-ray Transient Absorption Spectroscopy and DFT Calculations

Directory of Open Access Journals (Sweden)

Xiaoyi Zhang

2016-02-01

Full Text Available Characterizing the geometric and electronic structures of individual photoexcited dye molecules in solution is an important step towards understanding the interfacial properties of photo-active electrodes. The broad family of “red sensitizers” based on osmium(II polypyridyl compounds often undergoes small photo-induced structural changes which are challenging to characterize. In this work, X-ray transient absorption spectroscopy with picosecond temporal resolution is employed to determine the geometric and electronic structures of the photoexcited triplet state of [Os(terpy2]2+ (terpy: 2,2′:6′,2″-terpyridine solvated in methanol. From the EXAFS analysis, the structural changes can be characterized by a slight overall expansion of the first coordination shell [OsN6]. DFT calculations supports the XTA results. They also provide additional information about the nature of the molecular orbitals that contribute to the optical spectrum (with TD-DFT and the near-edge region of the X-ray spectra.

Principles of electron tunneling spectroscopy

CERN Document Server

Wolf, E L

2012-01-01

Electron tunnelling spectroscopy as a research tool has strongly advanced understanding of superconductivity. This book explains the physics and instrumentation behind the advances illustrated in beautiful images of atoms, rings of atoms and exotic states in high temperature superconductors, and summarizes the state of knowledge that has resulted.

Application of FTIR spectroscopy to the characterization of archeological wood.

Science.gov (United States)

Traoré, Mohamed; Kaal, Joeri; Martínez Cortizas, Antonio

2016-01-15

Two archeological wood samples were studied by attenuated total reflectance Fourier transform infrared (FTIR-ATR) spectroscopy. They originate from a shipwreck in Ribadeo Bay in the northwest of Spain and from a beam wood of an old nave of the Cathedral of Segovia in the central Spain. Principal component analysis was applied to the transposed data matrix (samples as columns and spectral bands as rows) of 43 recorded spectra (18 in the shipwreck and 25 in the beam wood). The results showed differences between the two samples, with a larger proportion of carbohydrates and smaller proportion of lignin in the beam than in the shipwreck wood. Within the beam wood, lignin content was significantly lower in the recent than the old tree rings (P=0.005). These variations can be attributed to species differences between the two woods (oak and pine respectively), with a mixture of guaiacyl and syringyl in hardwood lignin, whereas softwood lignin consists almost exclusively of guaiacyl moieties. The influence of environmental conditions on the FTIR fingerprint was probably reflected by enhanced oxidation of lignin in aerated conditions (beam wood) and hydrolysis of carbohydrates in submerged-anoxic conditions (shipwreck wood). Molecular characterization by analytical pyrolysis of selected samples from each wood type confirmed the interpretation of the mechanisms behind the variability in wood composition obtained by the FTIR-ATR. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiation damage analysis by positron annihilation spectroscopy

International Nuclear Information System (INIS)

Siegel, R.W.

1982-01-01

Positron annihilation spectroscopy (PAS) has in recent years become a valuable new tool for investigating defects in metals. The ability of the positron to localize in a trapped state at various defect sites, in which the positron annihilates with unique characteristics, has enabled the positron to be used as a localized probe of these defect sites. Several reviews of the application of PAS to the study of defects in metals have been published, as have more general treatises on the applications of positron annihilation to the study of solids. PAS has made, and has considerably greater potential for, a significant contribution to radiation damage analysis in two areas of importance: (1) the determination of atomic-defect properties, a knowledge of which is necessary for the modeling required to couple the results of model experiments using electron and ion irradiation with the expected irradiation conditions of reactor systems, and (2) the monitoring and characterization of irradiation-induced microstructure development. A unique aspect of PAS for radiation damage analysis is the defect specificity of the annihilation characteristics of a trapped positron. In addition to its value as an independent analytical tool, PAS can be a useful complement to more traditional techniques for defect studies

Characterization of metallic nanoparticles by high-resolution X-ray absorption and X-ray emission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kuehn, Timna-Josua

2012-03-15

In almost all areas of technology, metallic nanoparticles are of interest due to their special thermal, electronic, magnetic and optical properties. Their special properties are mainly due to their small size which implies the relevance of quantum effects as well as the significance of the surface: For 2 nm nanoparticles, the surface-to-volume ratio is already 1:1. However, the identification of surface-to-volume interactions - that are responsible for the new properties - is a difficult task due to the small size that inhibits a lot of 'standard' techniques to be applicable. Here X-ray absorption/emission spectroscopy (XAS/XES) is a favorable tool for the characterization of nanoparticles, independent on size, degree of crystallinity and shape/condition of the surface. Using XAS, a tempered nanosized Co{sub 3}Pt/C catalyst have been investigated. Its outstanding oxygen-reduction reaction (ORR) properties in a fuel cell could be related to a lowered Pt 5d-band center connected to a tightened Pt-Pt bonding distance, leading to a weakening of the oxygen adsorption strength so that the ORR may proceed faster. One drawback remains, however, as the properties found by (standard) XAS are summed up for different chemical environments of the chosen element. Thus, no distinction can be made between, e.g., the pure metal in a nanoparticles' interior and the ligated metal in the outer shells or surface. Here, high-resolution fluorescence-detected XAS (HRFD-XAS) provides additional opportunities as, due to its chemical sensitivity, it leads to site-selective XAS. For a system of 6 nm sized Co nanoparticles, build up of a metallic core surrounded by a protecting shell, that resulted from the 'smooth oxidation' process, this technique of site-selective XAS was proven to be applicable. For the first time, the interior and outer shell of a metallic nanoparticle could be characterized separately. In particular, the Co-hcp phase could be determined for the

Surface characterization of insulin protofilaments and fibril polymorphs using tip-enhanced Raman spectroscopy (TERS).

Science.gov (United States)

Kurouski, Dmitry; Deckert-Gaudig, Tanja; Deckert, Volker; Lednev, Igor K

2014-01-07

Amyloid fibrils are β-sheet-rich protein aggregates that are strongly associated with a variety of neurodegenerative maladies, such as Alzheimer's and Parkinson's diseases. Even if the secondary structure of such fibrils is well characterized, a thorough understanding of their surface organization still remains elusive. Tip-enhanced Raman spectroscopy (TERS) is one of a few techniques that allow the direct characterization of the amino acid composition and the protein secondary structure of the amyloid fibril surface. Herein, we investigated the surfaces of two insulin fibril polymorphs with flat (flat) and left-twisted (twisted) morphology. It was found that the two differ substantially in both amino acid composition and protein secondary structure. For example, the amounts of Tyr, Pro, and His differ, as does the number of carboxyl groups on the respective surfaces, whereas the amounts of Phe and of positively charged amino and imino groups remain similar. In addition, the surface of protofilaments, the precursors of the mature flat and twisted fibrils, was investigated using TERS. The results show substantial differences with respect to the mature fibrils. A correlation of amino acid frequencies and protein secondary structures on the surface of protofilaments and on flat and twisted fibrils allowed us to propose a hypothetical mechanism for the propagation to specific fibril polymorphs. This knowledge can shed a light on the toxicity of amyloids and define the key factors responsible for fibril polymorphism. Finally, this work demonstrates the potential of TERS for the surface characterization of amyloid fibril polymorphs. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Spectroscopy as a diagnostic tool for urban soil

Science.gov (United States)

Brook, Anna; Kopel, Daniella; Wittenberg, Lea

2015-04-01

Anthropogenic urban soil are the foundation of the urban green infrastructure, the green net quality is as good as each of its patches. In early days of pedology urban soil has been recognized with respect to contamination and the risks for human health but in study performed since the 70s, the importance of urban soil for the urban ecology became increasingly significant (Gómez-Baggethun and Barton 2013). Urban soils are highly disturbed land that was created by the process of urbanization. The dominant agent in the creation of urban soils is human activity which modifies the natural soil through mixing, filling or by contamination of land surfaces so as to create a layer of urban soil which can be more than 50 cm thick (Pavao-Zuckerman 2008). The objective of this study is to determine the extent to which field spectroscopy methods can be used to extend the knowledge of urban soils features and components. The majority of the studies on urban soils concentrate on identifying and mapping of pollution mostly heavy metals. In this study a top-down analysis is developed - a simple and intuitive spectral feature for detecting the presence of minerals, organic matter and pollutants in mixed soil samples. The developed method uses spectral activity (SA) detection in a structured hierarchical approach to quickly and, more importantly, correctly identify dominant spectral features. The developed method is adopted by multiple in-production tools including continuum removal normalization, guided by polynomial generalization, and spectral-likelihood algorithms: orthogonal subspace projection (OSP) and iterative spectral mixture analysis (ISMA) were compared to feature likelihood methods (Li et al. 2014). Results of the proposed top-down unmixing method suggest that the analysis is made very fast due to the simplified hierarchy which avoids the high-learning curve associated with unmixing algorithms showed that the most abundant components were coarse organic matter 12

APROBA-Plus: A probabilistic tool to evaluate and express uncertainty in hazard characterization and exposure assessment of substances.

Science.gov (United States)

Bokkers, Bas G H; Mengelers, Marcel J; Bakker, Martine I; Chiu, Weihsueh A; Slob, Wout

2017-12-01

To facilitate the application of probabilistic risk assessment, the WHO released the APROBA tool. This tool applies lognormal uncertainty distributions to the different aspects of the hazard characterization, resulting in a probabilistic health-based guidance value. The current paper describes an extension, APROBA-Plus, which combines the output from the probabilistic hazard characterization with the probabilistic exposure to rapidly characterize risk and its uncertainty. The uncertainty in exposure is graphically compared with the uncertainty in the target human dose, i.e. the dose that complies with the specified protection goals. APROBA-Plus is applied to several case studies, resulting in distinct outcomes and illustrating that APROBA-Plus could serve as a standard extension of routine risk assessments. By visualizing the uncertainties, APROBA-Plus provides a more transparent and informative outcome than the more usual deterministic approaches, so that risk managers can make better informed decisions. For example, APROBA-Plus can help in deciding whether risk-reducing measures are warranted or that a refined risk assessment would first be needed. If the latter, the tool can be used to prioritize possible refinements. APROBA-Plus may also be used to rank substances into different risk categories, based on potential health risks without being compromised by different levels of conservatism that may be associated with point estimates of risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spectroscopy and optical diagnostics for gases

CERN Document Server

Hanson, Ronald K; Goldenstein, Christopher S

2016-01-01

This text provides an introduction to the science that governs the interaction of light and matter (in the gas phase). It provides readers with the basic knowledge to exploit the light-matter interaction to develop quantitative tools for gas analysis (i.e. optical diagnostics) and understand and interpret the results of spectroscopic measurements. The authors pair the basics of gas‐phase spectroscopy with coverage of key optical diagnostic techniques utilized by practicing engineers and scientists to measure fundamental flow‐field properties. The text is organized to cover three sub‐topics of gas‐phase spectroscopy: (1) spectral line positions, (2) spectral line strengths, and (3) spectral lineshapes by way of absorption, emission, and scattering interactions. The latter part of the book describes optical measurement techniques and equipment. Key subspecialties include laser induced fluorescence, tunable laser absorption spectroscopy, and wavelength modulation spectroscopy. It is ideal for students an...

CHARACTERIZATION OF NEW TOOL STEEL FOR ALUMINUM EXTRUSION DIES

Directory of Open Access Journals (Sweden)

José Britti Bacalhau

2014-06-01

Full Text Available Aluminum extrusion dies are an important segment of application on industrial tools steels, which are manufactured in steels based on AISI H13 steel. The main properties of steels applied to extrusion dies are: wear resistance, impact resistance and tempering resistance. The present work discusses the characteristics of a newly developed hot work steel to be used on aluminum extrusion dies. The effects of Cr and Mo contents with respect to tempering resistance and the Al addition on the nitriding response have been evaluated. From forged steel bars, Charpy impact test and characterization via EPMA have been conducted. The proposed contents of Cr, Mo, and Al have attributed to the new VEX grade a much better tempering resistance than H13, as well as a deeper and harder nitrided layer. Due to the unique characteristics, this new steel provides an interesting alternative to the aluminum extrusion companies to increase their competitiveness.

Applied spectroscopy and the science of nanomaterials

CERN Document Server

2015-01-01

This book focuses on several areas of intense topical interest related to applied spectroscopy and the science of nanomaterials. The eleven chapters in the book cover the following areas of interest relating to applied spectroscopy and nanoscience: ·         Raman spectroscopic characterization, modeling and simulation studies of carbon nanotubes, ·         Characterization of plasma discharges using laser optogalvanic spectroscopy, ·         Fluorescence anisotropy in understanding protein conformational disorder and aggregation, ·         Nuclear magnetic resonance spectroscopy in nanomedicine, ·         Calculation of Van der Waals interactions at the nanoscale, ·         Theory and simulation associated with adsorption of gases in nanomaterials, ·         Atom-precise metal nanoclusters, ·         Plasmonic properties of metallic nanostructures, two-dimensional materials, and their composites, ·         Applications of graphe...

Cancer diagnosis by infrared spectroscopy: methodological aspects

Science.gov (United States)

Jackson, Michael; Kim, Keith; Tetteh, John; Mansfield, James R.; Dolenko, Brion; Somorjai, Raymond L.; Orr, F. W.; Watson, Peter H.; Mantsch, Henry H.

1998-04-01

IR spectroscopy is proving to be a powerful tool for the study and diagnosis of cancer. The application of IR spectroscopy to the analysis of cultured tumor cells and grading of breast cancer sections is outlined. Potential sources of error in spectral interpretation due to variations in sample histology and artifacts associated with sample storage and preparation are discussed. The application of statistical techniques to assess differences between spectra and to non-subjectively classify spectra is demonstrated.

Solid-state characterization of triamcinolone acetonide nanosuspensiones by X-ray spectroscopy, ATR Fourier transforms infrared spectroscopy and differential scanning calorimetry analysis

Directory of Open Access Journals (Sweden)

Eva García-Millán

2017-12-01

Full Text Available The data presented in this article describe the physical state of the triamcinolone acetonide (TA in nanosuspension stabilized with polyvinyl alcohol (PVA and poloxamer 407 (PL. The data were assessed by X-ray spectroscopy, ATR Fourier transforms infrared spectroscopy measurements (FTIR, and Differential scanning calorimetry (DSC analysis. PVA, PL and polymeric mixture (PVA and PL were compared with nanosuspension and the interactions between drug triamcinolone acetonide and polymers were studied. The data are related and are complementary to the research article entitle “Improved release of triamcinolone acetonide from medicated soft contact lenses loaded with drug nanosuspensions” (García-Millán et al., 2017 [1]. Keywords: Triamcinolona acetonide nanosuspensiones, X-ray spectroscopy, FTIR spectroscopy, DSC

Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Mascali, David, E-mail: davidmascali@lns.infn.it; Castro, Giuseppe; Celona, Luigi; Neri, Lorenzo; Gammino, Santo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Biri, Sándor; Rácz, Richárd; Pálinkás, József [Institute for Nuclear Research (Atomki), Hungarian Academy of Sciences, Bem tér 18/c, H-4026 Debrecen (Hungary); Caliri, Claudia [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università degli Studi di Catania, Dip.to di Fisica e Astronomia, via Santa Sofia 64, 95123 Catania (Italy); Romano, Francesco Paolo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); CNR, Istituto per i Beni Archeologici e Monumentali, Via Biblioteca 4, 95124 Catania (Italy); Torrisi, Giuseppe [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università Mediterranea di Reggio Calabria, DIIES, Via Graziella, I-89100 Reggio Calabria (Italy)

2016-02-15

An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed “on-line” during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and the beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.

Electrochemical impedance spectroscopy for quantitative interface state characterization of planar and nanostructured semiconductor-dielectric interfaces

Science.gov (United States)

Meng, Andrew C.; Tang, Kechao; Braun, Michael R.; Zhang, Liangliang; McIntyre, Paul C.

2017-10-01

The performance of nanostructured semiconductors is frequently limited by interface defects that trap electronic carriers. In particular, high aspect ratio geometries dramatically increase the difficulty of using typical solid-state electrical measurements (multifrequency capacitance- and conductance-voltage testing) to quantify interface trap densities (D it). We report on electrochemical impedance spectroscopy (EIS) to characterize the energy distribution of interface traps at metal oxide/semiconductor interfaces. This method takes advantage of liquid electrolytes, which provide conformal electrical contacts. Planar Al2O3/p-Si and Al2O3/p-Si0.55Ge0.45 interfaces are used to benchmark the EIS data against results obtained from standard electrical testing methods. We find that the solid state and EIS data agree very well, leading to the extraction of consistent D it energy distributions. Measurements carried out on pyramid-nanostructured p-Si obtained by KOH etching followed by deposition of a 10 nm ALD-Al2O3 demonstrate the application of EIS to trap characterization of a nanostructured dielectric/semiconductor interface. These results show the promise of this methodology to measure interface state densities for a broad range of semiconductor nanostructures such as nanowires, nanofins, and porous structures.

Characterization of the Roraima savanna across of X-ray diffraction, thermomagnetic analysis and Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Silva, Gilmar A.; Araujo, R.C.; Sergio, C.S. [Universidade Federal de Roraima (UFRR), Boa Vista, RR (Brazil)

2012-07-01

Full text: The technique of X-ray diffraction has great resolving power to determine the phases present in crystalline material, thereby enabling it to determine the elements present in the materials as well as changes in structure that they can suffer when subjected to various physical processes and/or chemical means. The research had as objective to characterize the mineralogy of iron oxides, silicon, aluminum and other minerals in the soil of five points of the Roraima savannah. The points where samples were collected are five municipalities in the state of Roraima. The area of sampling is part of the savanna in Roraima. The samples were collected. We analyzed samples from five points from the collection of natural soil in the locations listed. The samples were placed in a mill to a uniform grain size. After the milling process, the magnetic material was separated using a permanent magnet. Then the samples were analyzed by x-ray diffraction, thermomagnetic analysis and Moessbauer spectroscopy. Preliminary results of XRD showed the occurrence of phases of oxides of iron, silicon, aluminum and other phases less. Thermomagnetic analysis show that the magnetic phases are magnetite and hematite. The results of the Moessbauer spectroscopy indicates the reliability in the two prior art and confirmed the presence of the phases of oxides of iron present in the soil analyzed. (author)

Surface Enhanced Raman Spectroscopy (SERS) and multivariate analysis as a screening tool for detecting Sudan I dye in culinary spices

Science.gov (United States)

Di Anibal, Carolina V.; Marsal, Lluís F.; Callao, M. Pilar; Ruisánchez, Itziar

2012-02-01

Raman spectroscopy combined with multivariate analysis was evaluated as a tool for detecting Sudan I dye in culinary spices. Three Raman modalities were studied: normal Raman, FT-Raman and SERS. The results show that SERS is the most appropriate modality capable of providing a proper Raman signal when a complex matrix is analyzed. To get rid of the spectral noise and background, Savitzky-Golay smoothing with polynomial baseline correction and wavelet transform were applied. Finally, to check whether unadulterated samples can be differentiated from samples adulterated with Sudan I dye, an exploratory analysis such as principal component analysis (PCA) was applied to raw data and data processed with the two mentioned strategies. The results obtained by PCA show that Raman spectra need to be properly treated if useful information is to be obtained and both spectra treatments are appropriate for processing the Raman signal. The proposed methodology shows that SERS combined with appropriate spectra treatment can be used as a practical screening tool to distinguish samples suspicious to be adulterated with Sudan I dye.

Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles

Science.gov (United States)

Redding, Brandon; Schwab, Mark J.; Pan, Yong-le

2015-01-01

The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field. PMID:26247952

Advancing spaceborne tools for the characterization of planetary ionospheres and circumstellar environments

Science.gov (United States)

Douglas, Ewan Streets

This work explores remote sensing of planetary atmospheres and their circumstellar surroundings. The terrestrial ionosphere is a highly variable space plasma embedded in the thermosphere. Generated by solar radiation and predominantly composed of oxygen ions at high altitudes, the ionosphere is dynamically and chemically coupled to the neutral atmosphere. Variations in ionospheric plasma density impact radio astronomy and communications. Inverting observations of 83.4 nm photons resonantly scattered by singly ionized oxygen holds promise for remotely sensing the ionospheric plasma density. This hypothesis was tested by comparing 83.4 nm limb profiles recorded by the Remote Atmospheric and Ionospheric Detection System aboard the International Space Station to a forward model driven by coincident plasma densities measured independently via ground-based incoherent scatter radar. A comparison study of two separate radar overflights with different limb profile morphologies found agreement between the forward model and measured limb profiles. A new implementation of Chapman parameter retrieval via Markov chain Monte Carlo techniques quantifies the precision of the plasma densities inferred from 83.4 nm emission profiles. This first study demonstrates the utility of 83.4 nm emission for ionospheric remote sensing. Future visible and ultraviolet spectroscopy will characterize the composition of exoplanet atmospheres; therefore, the second study advances technologies for the direct imaging and spectroscopy of exoplanets. Such spectroscopy requires the development of new technologies to separate relatively dim exoplanet light from parent star light. High-contrast observations at short wavelengths require spaceborne telescopes to circumvent atmospheric aberrations. The Planet Imaging Concept Testbed Using a Rocket Experiment (PICTURE) team designed a suborbital sounding rocket payload to demonstrate visible light high-contrast imaging with a visible nulling coronagraph

Synthesis and Characterization of Carboxymethyl Chitosan Nanogels for Swelling Studies and Antimicrobial Activity

Directory of Open Access Journals (Sweden)

Reem K. Farag

2012-12-01

Full Text Available Nanogels of a binary system of carboxymethyl chitosan (CMCh and poly- (vinyl alcohol PVA, were successfully synthesized by a novel in situ process. They were also characterized by various analytical tools like Fourier transform infrared spectroscopy (FTIR, transmission electron microscopy (TEM and X-ray diffraction (XRD. They were studied for their unique swelling properties in water and different pH solutions. They were also investigated for their great ability to capture or isolate bacteria and fungi from aquatic environments.

Analysis of fresco by laser induced breakdown spectroscopy

International Nuclear Information System (INIS)

Caneve, L.; Diamanti, A.; Grimaldi, F.; Palleschi, G.; Spizzichino, V.; Valentini, F.

2010-01-01

The laser-based techniques have been shown to be a very powerful tool for artworks characterization and are used in the field of cultural heritage for the offered advantages of minimum invasiveness, in situ applicability and high sensitivity. Laser induced breakdown spectroscopy, in particular, has been applied in this field to many different kinds of ancient materials with successful results. In this work, a fragment of a Roman wall painting from the archaeological area of Pompeii has been investigated by LIBS. The sample elemental composition resulting from LIBS measurements suggested the presence of certain pigments. The ratio of the intensities of different lines related to some characteristic elements is proposed as an indicator for pigment recognition. The depth profiling permitted to put in evidence the presence of successive paint layers with different compositions. A comparison with the results obtained by the microscopy inspection of the sample has been done.

New advanced characterization tools for PW-class lasers (Conference Presentation)

Science.gov (United States)

Quéré, Fabien

2017-05-01

Spatio-temporal couplings (STC) of laser beams are ubiquitous in ultrafast optics. In the femtosecond range, chirped-pulse amplification (CPA), the key technology of amplified ultrashort pulses, relies on the use of massive STCs induced at different locations in laser systems (for instance by gratings or prisms), which should all eventually perfectly cancel out at the laser output. Residual STCs, for example resulting from imperfect compensation, decrease the peak intensity at focus by increasing both the focal spot size and the pulse duration. This is particularly detrimental for ultrahigh-intensity (UHI) lasers, which aim for the highest possible peak intensities. However, it is precisely with these lasers that such uncontrolled defects are most likely to occur, due to the complexity of these systems and the large diameters of the output beams. Accurately measuring STCs is thus essential in ultrafast optics. Significant progress has been made in the last decade, and several techniques are now available for the partial or complete spatiotemporal characterization of near-visible femtosecond laser beams. However, none of these has yet been applied to UHI femtosecond lasers, due to the difficulty of handling these large and powerful beams. As a result, all UHI lasers are currently characterized under the unjustified and unverified assumption of the absence of STCs, using separate measurements in space and time. This situation is now becoming a major bottleneck for the development of UHI lasers and their applications. In particular, the optimal and reliable operation of PW-class lasers now available or under construction all around the world will simply not be possible without a proper spatiotemporal metrology. In this talk, we present the first complete spatiotemporal experimental reconstruction of the field E(t,r) for a 100 TW peak-power laser, obtained using self-referenced spatially-resolved Fourier transform spectroscopy [1,2], and thus reveal the spatiotemporal

Development of a surrogate model for elemental analysis using a natural gamma ray spectroscopy tool

International Nuclear Information System (INIS)

Zhang, Qiong

2015-01-01

A systematic computational method for obtaining accurate elemental standards efficiently for varying borehole conditions was developed based on Monte Carlo simulations, surrogate modeling, and data assimilation. Elemental standards are essential for spectral unfolding in formation evaluation applications commonly used for nuclear well logging tools. Typically, elemental standards are obtained by standardized measurements, but these experiments are expensive and lack the flexibility to address different logging conditions. In contrast, computer-based Monte Carlo simulations provide an accurate and more flexible approach to obtaining elemental standards for formation evaluation. The presented computational method recognizes that in contrast to typical neutron–photon simulations, where the source is typically artificial and well characterized (Galford, 2009), an accurate knowledge of the source is essential for matching the obtained Monte Carlo elemental standards with their experimental counterparts. Therefore, source distributions are adjusted to minimize the L2 difference of the Monte Carlo computed and experimental standards. Subsequently, an accurate surrogate model is developed accounting for different casing and cement thicknesses, and tool positions within the borehole. The adjusted source distributions are then utilized to generate and validate spectra for varying borehole conditions: tool position, casing and cement thickness. The effect of these conditions on the spectra are investigated and discussed in this work. Given that Monte Carlo modeling provides much lower cost and more flexibility, employing Monte Carlo could enhance the processing of nuclear tool logging data computed standards. - Highlights: • A novel computational model for efficiently computing elemental standards for varying borehole conditions has been developed. • A model of an experimental test pit was implemented in the Monte Carlo code GEANT4 for computing elemental standards. �

Exploratory investigations of hypervelocity intact capture spectroscopy

Science.gov (United States)

Tsou, P.; Griffiths, D. J.

1993-01-01

The ability to capture hypervelocity projectiles intact opens a new technique available for hypervelocity research. A determination of the reactions taking place between the projectile and the capture medium during the process of intact capture is extremely important to an understanding of the intact capture phenomenon, to improving the capture technique, and to developing a theory describing the phenomenon. The intact capture of hypervelocity projectiles by underdense media generates spectra, characteristic of the material species of projectile and capture medium involved. Initial exploratory results into real-time characterization of hypervelocity intact capture techniques by spectroscopy include ultra-violet and visible spectra obtained by use of reflecting gratings, transmitting gratings, and prisms, and recorded by photographic and electronic means. Spectrometry proved to be a valuable real-time diagnostic tool for hypervelocity intact capture events, offering understanding of the interactions of the projectile and the capture medium during the initial period and providing information not obtainable by other characterizations. Preliminary results and analyses of spectra produced by the intact capture of hypervelocity aluminum spheres in polyethylene (PE), polystyrene (PS), and polyurethane (PU) foams are presented. Included are tentative emission species identifications, as well as gray body temperatures produced in the intact capture process.

Psychometric characterization of the obstetric communication assessment tool for medical education: a pilot study.

Science.gov (United States)

Rodriguez, A Noel; DeWitt, Peter; Fisher, Jennifer; Broadfoot, Kirsten; Hurt, K Joseph

2016-06-11

To characterize the psychometric properties of a novel Obstetric Communication Assessment Tool (OCAT) in a pilot study of standardized difficult OB communication scenarios appropriate for undergraduate medical evaluation. We developed and piloted four challenging OB Standardized Patient (SP) scenarios in a sample of twenty-one third year OB/GYN clerkship students: Religious Beliefs (RB), Angry Father (AF), Maternal Smoking (MS), and Intimate Partner Violence (IPV). Five trained Standardized Patient Reviewers (SPRs) independently scored twenty-four randomized video-recorded encounters using the OCAT. Cronbach's alpha and Intraclass Correlation Coefficient-2 (ICC-2) were used to estimate internal consistency (IC) and inter-rater reliability (IRR), respectively. Systematic variation in reviewer scoring was assessed using the Stuart-Maxwell test. IC was acceptable to excellent with Cronbach's alpha values (and 95% Confidence Intervals [CI]): RB 0.91 (0.86, 0.95), AF 0.76 (0.62, 0.87), MS 0.91 (0.86, 0.95), and IPV 0.94 (0.91, 0.97). IRR was unacceptable to poor with ICC-2 values: RB 0.46 (0.40, 0.53), AF 0.48 (0.41, 0.54), MS 0.52 (0.45, 0.58), and IPV 0.67 (0.61, 0.72). Stuart-Maxwell analysis indicated systematic differences in reviewer stringency. Our initial characterization of the OCAT demonstrates important issues in communications assessment. We identify scoring inconsistencies due to differences in SPR rigor that require enhanced training to improve assessment reliability. We outline a rational process for initial communication tool validation that may be useful in undergraduate curriculum development, and acknowledge that rigorous validation of OCAT training and implementation is needed to create a valuable OB communication assessment tool.

Microstructure Evolution and Impedance Spectroscopy Characterization of Thermal Barrier Coating Exposed to Gas Thermal-shock Environment

Directory of Open Access Journals (Sweden)

CHEN Wen-long

2017-10-01

Full Text Available Gas thermal-shock experiment of thermal barrier coatings (TBCs was carried out in air up to 1250℃ in order to simulate the thermal cycling process of the engine blades during the start heating and shut down cooling. The growth of thermal growth oxide (TGO layer and microstructure evolution of YSZ layer during thermal cycling process were investigated systematically by electrochemical impedance spectroscopy testing and SEM. The results show that the thickness of TGO layer increases when increasing the frequency of thermal cycling, and the impedance response of middle frequencies is more and more remarkable. Meanwhile, initiation and growth of micro-cracks occur in YSZ layer during the gas thermal-shock experiment. The corresponding impedance characterization of YSZ layer after 100 cycles is similar to the as-sprayed sample, indicating that micro-cracks in short time could heal since the YSZ micro-cracks sinter at high temperature. But after 300 cycles, the impedance spectroscopy of YSZ layer is quite different to the as-sprayed sample, with the corresponding impedance of particle-gap of YSZ more and more remarkable with the increase of the thermal-shock times, indicating that non-healing micro-cracks form in the YSZ layer, which may be the main reason to induce the failure of YSZ layer.

Role of Raman spectroscopy and surface enhanced Raman spectroscopy in colorectal cancer

Science.gov (United States)

Jenkins, Cerys A; Lewis, Paul D; Dunstan, Peter R; Harris, Dean A

2016-01-01

Colorectal cancer (CRC) is the fourth most common cancer in the United Kingdom and is the second largest cause of cancer related death in the United Kingdom after lung cancer. Currently in the United Kingdom there is not a diagnostic test that has sufficient differentiation between patients with cancer and those without cancer so the current referral system relies on symptomatic presentation in a primary care setting. Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are forms of vibrational spectroscopy that offer a non-destructive method to gain molecular information about biological samples. The techniques offer a wide range of applications from in vivo or in vitro diagnostics using endoscopic probes, to the use of micro-spectrometers for analysis of biofluids. The techniques have the potential to detect molecular changes prior to any morphological changes occurring in the tissue and therefore could offer many possibilities to aid the detection of CRC. The purpose of this review is to look at the current state of diagnostic technology in the United Kingdom. The development of Raman spectroscopy and SERS in clinical applications relation for CRC will then be discussed. Finally, future areas of research of Raman/SERS as a clinical tool for the diagnosis of CRC are also discussed. PMID:27190582

Characterization of toners and inkjets by laser ablation spectrochemical methods and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy

International Nuclear Information System (INIS)

Trejos, Tatiana; Corzo, Ruthmara; Subedi, Kiran; Almirall, José

2014-01-01

Detection and sourcing of counterfeit currency, examination of counterfeit security documents and determination of authenticity of medical records are examples of common forensic document investigations. In these cases, the physical and chemical composition of the ink entries can provide important information for the assessment of the authenticity of the document or for making inferences about common source. Previous results reported by our group have demonstrated that elemental analysis, using either Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) or Laser Ablation Induced Breakdown Spectroscopy (LIBS), provides an effective, practical and robust technique for the discrimination of document substrates and writing inks with minimal damage to the document. In this study, laser-based methods and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) methods were developed, optimized and validated for the forensic analysis of more complex inks such as toners and inkjets, to determine if their elemental composition can differentiate documents printed from different sources and to associate documents that originated from the same printing source. Comparison of the performance of each of these methods is presented, including the analytical figures of merit, discrimination capability and error rates. Different calibration strategies resulting in semi-quantitative and qualitative analysis, comparison methods (match criteria) and data analysis and interpretation tools were also developed. A total of 27 black laser toners originating from different manufacturing sources and/or batches were examined to evaluate the discrimination capability of each method. The results suggest that SEM-EDS offers relatively poor discrimination capability for this set (∼ 70.7% discrimination of all the possible comparison pairs or a 29.3% type II error rate). Nonetheless, SEM-EDS can still be used as a complementary method of analysis since it has

Characterization of toners and inkjets by laser ablation spectrochemical methods and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Trejos, Tatiana, E-mail: trejost@fiu.edu; Corzo, Ruthmara, E-mail: rcorz001@fiu.edu; Subedi, Kiran, E-mail: ksube001@fiu.edu; Almirall, José, E-mail: almirall@fiu.edu

2014-02-01

Detection and sourcing of counterfeit currency, examination of counterfeit security documents and determination of authenticity of medical records are examples of common forensic document investigations. In these cases, the physical and chemical composition of the ink entries can provide important information for the assessment of the authenticity of the document or for making inferences about common source. Previous results reported by our group have demonstrated that elemental analysis, using either Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) or Laser Ablation Induced Breakdown Spectroscopy (LIBS), provides an effective, practical and robust technique for the discrimination of document substrates and writing inks with minimal damage to the document. In this study, laser-based methods and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) methods were developed, optimized and validated for the forensic analysis of more complex inks such as toners and inkjets, to determine if their elemental composition can differentiate documents printed from different sources and to associate documents that originated from the same printing source. Comparison of the performance of each of these methods is presented, including the analytical figures of merit, discrimination capability and error rates. Different calibration strategies resulting in semi-quantitative and qualitative analysis, comparison methods (match criteria) and data analysis and interpretation tools were also developed. A total of 27 black laser toners originating from different manufacturing sources and/or batches were examined to evaluate the discrimination capability of each method. The results suggest that SEM-EDS offers relatively poor discrimination capability for this set (∼ 70.7% discrimination of all the possible comparison pairs or a 29.3% type II error rate). Nonetheless, SEM-EDS can still be used as a complementary method of analysis since it has

Teaching UV-Vis Spectroscopy with a 3D-Printable Smartphone Spectrophotometer

Science.gov (United States)

Grasse, Elise K.; Torcasio, Morgan H.; Smith, Adam W.

2016-01-01

Visible absorbance spectroscopy is a widely used tool in chemical, biochemical, and medical laboratories. The theory and methods of absorbance spectroscopy are typically introduced in upper division undergraduate chemistry courses, but could be introduced earlier with the right curriculum and instrumentation. A major challenge in teaching…

Using 3D Printing for Rapid Prototyping of Characterization Tools for Investigating Powder Blend Behavior

DEFF Research Database (Denmark)

Hirschberg, Cosima; Boetker, Johan P; Rantanen, Jukka

2018-01-01

of complex powder behavior, such as mixing process and segregation phenomenon. An approach based on the fast prototyping of new powder handling geometries and interfacing solutions for process analytical tools is reported. This study utilized 3D printing for rapid prototyping of customized geometries...... the percolation thresholds. Blends with a paracetamol wt% above the percolation threshold were subsequently investigated in relation to their segregation behavior. Rapid prototyping using 3D printing allowed designing two funnels with tailored flow behavior (funnel flow) of model formulations, which could...... blend were monitored during blending. Rapid prototyping allowed for fast modification of powder testing geometries and easy interfacing with process analytical tools, opening new possibilities for more detailed powder characterization....

Automated riverine landscape characterization: GIS-based tools for watershed-scale research, assessment, and management.

Science.gov (United States)

Williams, Bradley S; D'Amico, Ellen; Kastens, Jude H; Thorp, James H; Flotemersch, Joseph E; Thoms, Martin C

2013-09-01

River systems consist of hydrogeomorphic patches (HPs) that emerge at multiple spatiotemporal scales. Functional process zones (FPZs) are HPs that exist at the river valley scale and are important strata for framing whole-watershed research questions and management plans. Hierarchical classification procedures aid in HP identification by grouping sections of river based on their hydrogeomorphic character; however, collecting data required for such procedures with field-based methods is often impractical. We developed a set of GIS-based tools that facilitate rapid, low cost riverine landscape characterization and FPZ classification. Our tools, termed RESonate, consist of a custom toolbox designed for ESRI ArcGIS®. RESonate automatically extracts 13 hydrogeomorphic variables from readily available geospatial datasets and datasets derived from modeling procedures. An advanced 2D flood model, FLDPLN, designed for MATLAB® is used to determine valley morphology by systematically flooding river networks. When used in conjunction with other modeling procedures, RESonate and FLDPLN can assess the character of large river networks quickly and at very low costs. Here we describe tool and model functions in addition to their benefits, limitations, and applications.

Atomic Force Microscopy as a Tool for Asymmetric Polymeric Membrane Characterization

International Nuclear Information System (INIS)

Abdul Wahab Mohammad; Pei, L.Y.; Indok Nurul Hasyimah Mohd Amin; Rafeqah Raslan

2011-01-01

Atomic force microscopy (AFM) has a wide range of applications and is rapidly growing in research and development. This powerful technique has been used to visualize surfaces both in liquid or gas media. It has been considered as an effective tool to investigate the surface structure for its ability to generate high-resolution 3D images at a subnanometer range without sample pretreatment. In this paper, the use of AFM to characterize the membrane roughness is presented for commercial and self-prepared membranes for specific applications. Surface roughness has been regarded as one of the most important surface properties, and has significant effect in membrane permeability and fouling behaviour. Several scan areas were used to compare surface roughness for different membrane samples. Characterization of the surfaces was achieved by measuring the average roughness (R a ) and root mean square roughness (R rms ) of the membrane. AFM image shows that the membrane surface was composed entirely of peaks and valleys. Surface roughness is substantially greater for commercial available hydrophobic membranes, in contrast to self-prepared membranes. This study also shows that foulants deposited on membrane surface would increase the membrane roughness. (author)

Structure and nature of the metal-support interface: characterization of iridium clusters on magnesium oxide by extended x-ray absorption fine structure spectroscopy

NARCIS (Netherlands)

Zon, van F.B.M.; Maloney, S.D.; Gates, B.C.; Koningsberger, D.C.

1993-01-01

X-ray absorption spectroscopy was used to characterize the metal-support interface in catalysts consisting of very small Ir clusters of nearly uniform nuclearity on the surface of MgO powder. [Ir4(CO)12] on MgO was converted in high yield into [HIr4(CO)11]- and sep. into [Ir6(CO)15]2-. EXAFS data

Infrared spectroscopy: a tool for determination of the degree of conversion in dental composites

Directory of Open Access Journals (Sweden)

Luciene Gonçalves Palmeira Moraes

2008-04-01

Full Text Available Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree.

Spectrally interleaved, comb-mode-resolved spectroscopy using swept dual terahertz combs.

Science.gov (United States)

Hsieh, Yi-Da; Iyonaga, Yuki; Sakaguchi, Yoshiyuki; Yokoyama, Shuko; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Araki, Tsutomu; Yasui, Takeshi

2014-01-22

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10(-7) in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

Spectrally interleaved, comb-mode-resolved spectroscopy using swept dual terahertz combs

Science.gov (United States)

Hsieh, Yi-Da; Iyonaga, Yuki; Sakaguchi, Yoshiyuki; Yokoyama, Shuko; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Araki, Tsutomu; Yasui, Takeshi

2014-01-01

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

Detailed characterization of anode-supported SOFCs by impedance spectroscopy

DEFF Research Database (Denmark)

Barfod, R.; Mogensen, Mogens Bjerg; Klemensø, Trine

2007-01-01

Anode-supported thin electrolyte cells are studied by electrochemical impedance spectroscopy (EIS). The aim is to describe how the losses of this type of cells are distributed at low current density (around open-circuit voltage) as a function of temperature. An equivalent circuit consisting...

Synthesis and characterization of germa[n]pericyclynes.

Science.gov (United States)

Tanimoto, Hiroki; Nagao, Tomohiko; Nishiyama, Yasuhiro; Morimoto, Tsumoru; Iseda, Fumiyasu; Nagato, Yuko; Suzuka, Toshimasa; Tsutsumi, Ken; Kakiuchi, Kiyomi

2014-06-14

The synthesis and characterization of novel pericyclynes comprising germanium atoms and acetylenes, germa[n]pericyclynes, are described. The prepared germa[4]-, [6]-, and [8]pericyclynes were compared by (13)C NMR spectroscopy, X-ray crystallography, cyclic voltammetry, UV-visible spectroscopy, fluorescence emission spectroscopy, Raman spectroscopy, and density functional theory calculation analyses.

High resolution X-ray emission spectroscopy: An advanced tool for actinide research

Science.gov (United States)

Vitova, T.; Brendebach, B.; Dardenne, K.; Denecke, M. A.; Lebid, A.; Löble, M.; Rothe, J.; Batuk, O. N.; Hormes, J.; Liu, D.; Breher, F.; Geckeis, H.

2010-03-01

High resolution X-ray emission spectroscopy (HRXES) is becoming increasingly important for our understanding of electronic and coordination structures. The combination of such information with development of quantum theoretical tools will advance our capability for predicting reactivity and physical behavior especially of 5f elements. HRXES can be used to remove lifetime broadening by registering the partial fluorescence yield emitted by the sample (i.e., recording a windowed signal from the energy dispersed fluorescence emission while varying incident photon energy), thereby yielding highly resolved X-ray absorption fine structure (XAFS) spectra. Such spectra often display resonant features not observed in conventional XAFS. The spectrometer set-up can also be used for a wide range of other experiments, for example, resonant inelastic X-ray scattering (RIXS), where bulk electron configuration information in solids, liquids and gases is obtained. Valence-selective XAFS studies, where the local structure of a selected element's valence state present in a mixture of valence states can be obtained, as well as site-selective XAFS studies, where the coordination structure of a metal bound to selected elements can be differentiated from that of all the other ligating atoms. A HRXES spectrometer has been constructed and is presently being commissioned for use at the INE-Beamline for actinide research at the synchrotron source ANKA at FZK. We present the spectrometer's compact, modular design, optimized for attaining a wide range of energies, and first test measurement results. Examples from HRXES studies of lanthanides, actinides counter parts, are also shown.

Positron Spectroscopy of Hydrothermally Grown Actinide Oxides

Science.gov (United States)

2014-03-27

actinide oxides . The work described here is an attempt to characterize the quality of crystals using positron annihilation spectroscopy (PALS). The...Upadhyaya, R. V. Muraleedharan, B. D. Sharma and K. G. Prasad, " Positron lifetime studies on thorium oxide powders," Philosohical Magazine A, vol. 45... crystals . A strong foundation for actinide PALS studies was laid, but further work is required to build a more effective system. Positron Spectroscopy

Development and characterization of Si3N4 coated AlCrN ceramic cutting tool

International Nuclear Information System (INIS)

Souza, J.V.C.; Nono, M.C.A.; Martins, G.V.; Machado, J.P.B.; Silva, O.M.M.

2009-01-01

Nowadays, silicon nitride based cutting tools are used to machine cast iron from the automotive industry and nickel superalloys from the aero industries. Advances in manufacturing technologies (increased cutting speeds, dry machining, etc.) induced the fast commercial growth of physical vapor deposition (PVD) coatings for cutting tools, in order to increase their life time. In this work, a new composition of the Si 3 N 4 ceramic cutting tool was developed, characterized and subsequently coated, using a PVD process, with aluminum chromium nitride (AlCrN). The Si 3 N 4 substrate properties were analyzed by XRD, AFM, hardness and fracture toughness. The AlCrN coating was analyzed by AFM, grazing incidence X-ray diffraction (GIXRD) and hardness. The results showed that this PVD coating could be formed homogeneously, without cracks and promoted a higher surface hardness to the insert and consequently it can produce a better wear resistance during its application on high speed machining. (author)

The role of MR spectroscopy in neurooncology

DEFF Research Database (Denmark)

Kozić, D; Ostojić, Jelena; Bjelan, M

2012-01-01

Magnetic resonance spectroscopy (MRS) is a diagnostic tool that provides information related to brain's metabolic activity. Literature data suggest that elevation of the ratio between the choline and creatine (the Cho/Cr ratio), the reduction of the ratio between n-acetyl-aspartate acid and creat......Magnetic resonance spectroscopy (MRS) is a diagnostic tool that provides information related to brain's metabolic activity. Literature data suggest that elevation of the ratio between the choline and creatine (the Cho/Cr ratio), the reduction of the ratio between n-acetyl-aspartate acid...... and creatine (the NAA/Cr ratio), increase of the ratio between myo-inositol and creatine (the MI/Cr ratio), and the presence of lipids and lactate are useful diagnostic markers in grading tumors as well as in the prediction of tumor malignancy potential. Two additional important roles of MRS...

New and improved method of investigation using thermal tools for characterization of cellulose from eucalypts pulp

Energy Technology Data Exchange (ETDEWEB)

Lengowski, Elaine Cristina, E-mail: elainelengowski@yahoo.com.br [Laboratório de Anatomia e Qualidade da Madeira – LANAQM, Departamento de Engenharia e Tecnologia Florestal – DETF/Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Magalhães, Washington Luiz Esteves, E-mail: washington.magalhaes@embrapa.br [Embrapa Florestas, Estrada da Ribeira km 111 P.O. Box 319, 83411-000 Colombo, PR (Brazil); Programa de Pós Graduação em Engenharia de Materiais – PIPE Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Nisgoski, Silvana, E-mail: silnis@yahoo.com [Laboratório de Anatomia e Qualidade da Madeira – LANAQM, Departamento de Engenharia e Tecnologia Florestal – DETF/Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Muniz, Graciela Inês Bolzon de, E-mail: graciela.ufpr@gmail.com [Laboratório de Anatomia e Qualidade da Madeira – LANAQM, Departamento de Engenharia e Tecnologia Florestal – DETF/Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Satyanarayana, Kestur Gundappa [Embrapa Florestas, Estrada da Ribeira km 111 P.O. Box 319, 83411-000 Colombo, PR (Brazil); Lazzarotto, Marcelo, E-mail: marcelo.lazzarotto@embrapa.br [Embrapa Florestas, Estrada da Ribeira km 111 P.O. Box 319, 83411-000 Colombo, PR (Brazil)

2016-08-20

Highlights: • Cellulose was treated to modify its crystallinity. • Cellulose was characterized by X-ray diffraction to evaluate Segal’s index. • TGA and DTA with chemometric tools were used to predict Segal’s index. • MLR model was applied to predict XRD cellulose Segal’s index from TGA curves. • MLR model was applied to predict XRD cellulose Segal’s index from DTA curves. - Abstract: Despite cellulose being the most abundant biopolymer on earth and an important commodity, there is a lack of deeper knowledge about its structure as well as faster and more efficient characterization techniques. This paper presents preparation of nanocellulose from bleached cellulose pulp of Eucalyptus by chemical and mechanical pre-treatments, while the cellulose was given treatment to obtain a great range of crystallinity index. The nanocellulose is characterized by X-ray diffraction to evaluate Segal’s index while chemometric tools by TGA and DTA were used to predict Segal’s index. DTA curves, along with multivariate statistical model, presented better result than TGA. The coefficient of variation and standard error of prediction for the proposed models using external validation samples were in the range of 0.91–0.96 and 4.18–8.71, respectively. These successful mathematical models are discussed by correlating them with the observed characteristics of cellulose.

New and improved method of investigation using thermal tools for characterization of cellulose from eucalypts pulp

International Nuclear Information System (INIS)

Lengowski, Elaine Cristina; Magalhães, Washington Luiz Esteves; Nisgoski, Silvana; Muniz, Graciela Inês Bolzon de; Satyanarayana, Kestur Gundappa; Lazzarotto, Marcelo

2016-01-01

Highlights: • Cellulose was treated to modify its crystallinity. • Cellulose was characterized by X-ray diffraction to evaluate Segal’s index. • TGA and DTA with chemometric tools were used to predict Segal’s index. • MLR model was applied to predict XRD cellulose Segal’s index from TGA curves. • MLR model was applied to predict XRD cellulose Segal’s index from DTA curves. - Abstract: Despite cellulose being the most abundant biopolymer on earth and an important commodity, there is a lack of deeper knowledge about its structure as well as faster and more efficient characterization techniques. This paper presents preparation of nanocellulose from bleached cellulose pulp of Eucalyptus by chemical and mechanical pre-treatments, while the cellulose was given treatment to obtain a great range of crystallinity index. The nanocellulose is characterized by X-ray diffraction to evaluate Segal’s index while chemometric tools by TGA and DTA were used to predict Segal’s index. DTA curves, along with multivariate statistical model, presented better result than TGA. The coefficient of variation and standard error of prediction for the proposed models using external validation samples were in the range of 0.91–0.96 and 4.18–8.71, respectively. These successful mathematical models are discussed by correlating them with the observed characteristics of cellulose.

Optical characterization of epitaxial semiconductor layers

CERN Document Server

Richter, Wolfgang

1996-01-01

The last decade has witnessed an explosive development in the growth of expitaxial layers and structures with atomic-scale dimensions. This progress has created new demands for the characterization of those stuctures. Various methods have been refined and new ones developed with the main emphasis on non-destructive in-situ characterization. Among those, methods which rely on the interaction of electromagnetic radiation with matter are particularly valuable. In this book standard methods such as far-infrared spectroscopy, ellipsometry, Raman scattering, and high-resolution X-ray diffraction are presented, as well as new advanced techniques which provide the potential for better in-situ characterization of epitaxial structures (such as reflection anistropy spectroscopy, infrared reflection-absorption spectroscopy, second-harmonic generation, and others). This volume is intended for researchers working at universities or in industry, as well as for graduate students who are interested in the characterization of ...

An introductory study using impedance spectroscopy technique with polarizable microelectrode for amino acids characterization

Science.gov (United States)

Chin, K. B.; Chi, I.; Pasalic, J.; Huang, C.-K.; Barge, Laura M.

2018-04-01

Portable, low power, yet ultra-sensitive life detection instrumentations are vital to future astrobiology flight programs at NASA. In this study, initial attempts to characterize amino acids in an aqueous environment by electrochemical impedance spectroscopy (EIS) using polarizable (blocking) electrodes in order to establish a means of detection via their electrical properties. Seven amino acids were chosen due to their scientific importance in demonstrating sensitivity levels in the range of part per billion concentration. Albeit more challenging in real systems of analyst mixtures, we found individual amino acids in aqueous environment do exhibit some degree of chemical and physical uniqueness to warrant characterization by EIS. The polar amino acids (Asp, Glu, and His) exhibited higher electrochemical activity than the non-polar amino acids (Ala, Gly, Val, and Leu). The non-polar amino acids (Gly and Ala) also exhibited unique electrical properties which appeared to be more dependent on physical characteristics such as molecular weight and structure. At concentrations above 1 mM where the amino acids play a more dominant transport role within the water, the conductivity was found to be more sensitive to concentrations. At lower concentrations activity with water. As revealed by equivalent circuit modeling, the relaxation times showed a 1-2 order of magnitude difference between polar and non-polar amino acids. The pseudo-capacitance from EIS measurements on sample mixtures containing salt water and individual amino acids revealed the possibility for improvement in amino acid selectivity using gold nanoporous surface enhanced electrodes. This work establishes important methodologies for characterizing amino acids using EIS combined with microscale electrodes, supporting the case for instrumentation development for life detection and origin of life programs.

High energy PIXE: A tool to characterize multi-layer thick samples

Science.gov (United States)

Subercaze, A.; Koumeir, C.; Métivier, V.; Servagent, N.; Guertin, A.; Haddad, F.

2018-02-01

High energy PIXE is a useful and non-destructive tool to characterize multi-layer thick samples such as cultural heritage objects. In a previous work, we demonstrated the possibility to perform quantitative analysis of simple multi-layer samples using high energy PIXE, without any assumption on their composition. In this work an in-depth study of the parameters involved in the method previously published is proposed. Its extension to more complex samples with a repeated layer is also presented. Experiments have been performed at the ARRONAX cyclotron using 68 MeV protons. The thicknesses and sequences of a multi-layer sample including two different layers of the same element have been determined. Performances and limits of this method are presented and discussed.

Purification and Characterization of Recombinant N-Terminally Pyroglutamate-Modified Amyloid-β Variants and Structural Analysis by Solution NMR Spectroscopy.

Directory of Open Access Journals (Sweden)

Christina Dammers

Full Text Available Alzheimer's disease (AD is the leading cause of dementia in the elderly and is characterized by memory loss and cognitive decline. Pathological hallmark of AD brains are intracellular neurofibrillary tangles and extracellular amyloid plaques. The major component of these plaques is the highly heterogeneous amyloid-β (Aβ peptide, varying in length and modification. In recent years pyroglutamate-modified amyloid-β (pEAβ peptides have increasingly moved into the focus since they have been described to be the predominant species of all N-terminally truncated Aβ. Compared to unmodified Aβ, pEAβ is known to show increased hydrophobicity, higher toxicity, faster aggregation and β-sheet stabilization and is more resistant to degradation. Nuclear magnetic resonance (NMR spectroscopy is a particularly powerful method to investigate the conformations of pEAβ isoforms in solution and to study peptide/ligand interactions for drug development. However, biophysical characterization of pEAβ and comparison to its non-modified variant has so far been seriously hampered by the lack of highly pure recombinant and isotope-enriched protein. Here we present, to our knowledge, for the first time a reproducible protocol for the production of pEAβ from a recombinant precursor expressed in E. coli in natural isotope abundance as well as in uniformly [U-15N]- or [U-13C, 15N]-labeled form, with yields of up to 15 mg/l E. coli culture broth. The chemical state of the purified protein was evaluated by RP-HPLC and formation of pyroglutamate was verified by mass spectroscopy. The recombinant pyroglutamate-modified Aβ peptides showed characteristic sigmoidal aggregation kinetics as monitored by thioflavin-T assays. The quality and quantity of produced pEAβ40 and pEAβ42 allowed us to perform heteronuclear multidimensional NMR spectroscopy in solution and to sequence-specifically assign the backbone resonances under near-physiological conditions. Our results suggest

Orientation Mapping of Extruded Polymeric Composites by Polarized Micro-Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Xiaoyun Chen

2015-01-01

Full Text Available 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.

High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

Energy Technology Data Exchange (ETDEWEB)

Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

2014-08-01

A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

Minimizing Characterization - Derived Waste at the Department of Energy Savannah River Site, Aiken, South Carolina

Energy Technology Data Exchange (ETDEWEB)

Van Pelt, R. S.; Amidon, M. B.; Reboul, S. H.

2002-02-25

Environmental restoration activities at the Department of Energy Savannah River Site (SRS) utilize innovative site characterization approaches and technologies that minimize waste generation. Characterization is typically conducted in phases, first by collecting large quantities of inexpensive data, followed by targeted minimally invasive drilling to collect depth-discrete soil/groundwater data, and concluded with the installation of permanent multi-level groundwater monitoring wells. Waste-reducing characterization methods utilize non-traditional drilling practices (sonic drilling), minimally intrusive (geoprobe, cone penetrometer) and non-intrusive (3-D seismic, ground penetration radar, aerial monitoring) investigative tools. Various types of sensor probes (moisture sensors, gamma spectroscopy, Raman spectroscopy, laser induced and X-ray fluorescence) and hydrophobic membranes (FLUTe) are used in conjunction with depth-discrete sampling techniques to obtain high-resolution 3-D plume profiles. Groundwater monitoring (short/long-term) approaches utilize multi-level sampling technologies (Strata-Sampler, Cone-Sipper, Solinst Waterloo, Westbay) and low-cost diffusion samplers for seepline/surface water sampling. Upon collection of soil and groundwater data, information is portrayed in a Geographic Information Systems (GIS) format for interpretation and planning purposes. At the SRS, the use of non-traditional drilling methods and minimally/non intrusive investigation approaches along with in-situ sampling methods has minimized waste generation and improved the effectiveness and efficiency of characterization activities.

Minimizing Characterization - Derived Waste at the Department of Energy Savannah River Site, Aiken, South Carolina

International Nuclear Information System (INIS)

Van Pelt, R. S.; Amidon, M. B.; Reboul, S. H.

2002-01-01

Environmental restoration activities at the Department of Energy Savannah River Site (SRS) utilize innovative site characterization approaches and technologies that minimize waste generation. Characterization is typically conducted in phases, first by collecting large quantities of inexpensive data, followed by targeted minimally invasive drilling to collect depth-discrete soil/groundwater data, and concluded with the installation of permanent multi-level groundwater monitoring wells. Waste-reducing characterization methods utilize non-traditional drilling practices (sonic drilling), minimally intrusive (geoprobe, cone penetrometer) and non-intrusive (3-D seismic, ground penetration radar, aerial monitoring) investigative tools. Various types of sensor probes (moisture sensors, gamma spectroscopy, Raman spectroscopy, laser induced and X-ray fluorescence) and hydrophobic membranes (FLUTe) are used in conjunction with depth-discrete sampling techniques to obtain high-resolution 3-D plume profiles. Groundwater monitoring (short/long-term) approaches utilize multi-level sampling technologies (Strata-Sampler, Cone-Sipper, Solinst Waterloo, Westbay) and low-cost diffusion samplers for seepline/surface water sampling. Upon collection of soil and groundwater data, information is portrayed in a Geographic Information Systems (GIS) format for interpretation and planning purposes. At the SRS, the use of non-traditional drilling methods and minimally/non intrusive investigation approaches along with in-situ sampling methods has minimized waste generation and improved the effectiveness and efficiency of characterization activities

Defect Characterization in Semiconductors with Positron Annihilation Spectroscopy

Science.gov (United States)

Tuomisto, Filip

Positron annihilation spectroscopy is an experimental technique that allows the selective detection of vacancy defects in semiconductors, providing a means to both identify and quantify them. This chapter gives an introduction to the principles of the positron annihilation techniques and then discusses the physics of some interesting observations on vacancy defects related to growth and doping of semiconductors. Illustrative examples are selected from studies performed in silicon, III-nitrides, and ZnO.

Characterization of oil-producing microalgae using Raman spectroscopy

Czech Academy of Sciences Publication Activity Database

Samek, Ota; Zemánek, Pavel; Jonáš, Alexandr; Telle, H.H.

2011-01-01

Roč. 8, č. 10 (2011), s. 701-709 ISSN 1612-2011 R&D Projects: GA MŠk OC08034; GA MŠk ED0017/01/01; GA ČR GAP205/11/1687 Grant - others:EC(XE) PERG 06-GA-2009-256526 Institutional research plan: CEZ:AV0Z20650511 Keywords : Raman spectroscopy * algae * lipids * biofuel * iodine value * microorganisms Subject RIV: BH - Optics, Masers, Lasers Impact factor: 9.970, year: 2011

Characterization of Shock Effects in Calcite by Raman Spectroscopy: Results of Experiments

Science.gov (United States)

Bell, M. S.

2016-01-01

Carbonates comprise approx. 20% by volume of present day Earth's sedimentary rocks and store most of the terrestrial CO2 inventory. Some of the oldest meta-sedimentary rocks found on Earth contain abundant carbonate from which impact-induced release of CO2 could have played a role in the formation and evolution of the atmosphere. Carbonates are also present in the target materials for approx. 30% of all terrestrial impact structures including large impacts such as Chicxulub which happened to occur at a location with extraordinarily thick platform carbonate 3-6 km deep. The impact release of CO2 from carbonates can cause global warming as a result of the well-known greenhouse effect and have subsequent effects on climate and biota. Therefore, the shock behavior of calcite is important in understanding the Cretaceous-Paleogene event and other impacts with carbonate-bearing sediments in their target(s) such as Mars and some asteroids. A comprehensive survey utilizing a variety of techniques to characterize the effects manifest in Calcite (Iceland Spar) experimentally shocked to 60.8 GPa has been completed. Results of analysis by Raman Spectroscopy are reported here.

Characterization of underground storage tank sludge using fourier transform infrared photoacoustic spectroscopy

International Nuclear Information System (INIS)

Luo, S.; Bajic, S.J.; Jones, R.W.

1994-01-01

Analysis of underground storage tank (UST) contents is critical for the determination of proper disposal protocols and storage procedures of nuclear waste materials. Tank volume reduction processes during the 1940's and 50's have produced a waste form that compositionally varies widely and has a consistency that ranges from paste like sludge to saltcake. The heterogeneity and chemical reactivity of the waste form makes analysis difficult by most conventional methods which require extensive sample preparation. In this paper, a method is presented to characterize nuclear waste from UST's at the Westinghouse Hanford Site in Washington State, using Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS). FTIR-PAS measurements on milligram amounts of surrogate sludge samples have been used to accurately identify phosphate, sulfate, nitrite, nitrate and ferrocyanide components. A simple sample preparation method was followed to provide a reproducible homogeneous sample for quantitative analysis. The sample preparation method involved freeze drying the sludge sample prior to analysis to prevent the migration of soluble species. Conventional drying (e.g., air or, oven) leads to the formation of crystals near the surface where evaporation occurs. Sample preparation as well as the analytical utility of this method will be discussed

Electrical and spectroscopic characterization of a surgical argon plasma discharge

International Nuclear Information System (INIS)

Keller, Sandra; Neugebauer, Alexander; Bibinov, Nikita; Awakowicz, Peter

2013-01-01

For electrosurgical procedures, the argon plasma coagulation (APC) discharge is a well-established atmospheric-pressure plasma tool for thermal haemostasis and devitalization of biological tissue. To characterize this plasma source, voltage-current measurements, microphotography, optical emission spectroscopy and numerical simulation are applied. Two discharge modes are established during the operation of the APC plasma source. A short transient spark discharge is ignited within the positive half period of the applied high voltage after a streamer channel connects the APC probe and the counter-electrode. During the second phase, which continues under negative high voltage, a glow discharge is stabilized in the plasma channel.

Synthesis and characterization of gold nanoparticles as diagnostic and therapeutic tool

International Nuclear Information System (INIS)

Costa, Pryscila Rodrigues da

2012-01-01

Nanomedicine covers the use of nanoparticles to the targeted site of action as platforms for building imaging and therapeutic agents against cancer and other human diseases. In particular, gold nanoparticles (AuNp's) have proven to be efficient for the diagnosis and therapy. Interest in the development of AuNp's is due to their extraordinary physical and chemical properties resulting from the effect of its size in the nanoscale, to have an area of easy modification and the radioactive γ and β emitter ( 198 Au; Eγ = 0,411 MeV, β max = 0,96 MeV; T 1/2 = 2,69 days), having the advantage of being able to be applied as a diagnostic tool for molecular photon emission tomography (SPECT) using only a small amount of radioactive gold . In this study were synthesized AuNp's, whose surface is functionalized with a biocompatible polymer (modified polyethylene glycol) and folic acid in order to render them stealth and specific tumors that over express the folate receptors. The techniques of Dynamic Light Scattering (DLS), zeta potential (ζ), transmission electron microscopy (TEM) and UV-Visible absorption spectroscopy were employed to characterization of the size and geometry of the nanoparticles, in addition to confirming its binding to thiol -PEG and PEG-thiol Folate. The results of UV-Visible and TEM showed the formation of dispersed AuNp's ranging in size from 8-12 nm with a strong absorption around 520 nm, relating to a maximum of surface plasmon resonance. DLS results showed a hydrodynamic diameter of 10 and 14 nm. The (pH ∼ 5.0 to 6.0) ranged ζ potential values of the dispersions prepared between -16.2 and -42.1 mV, indicating stable colloidal suspensions. To determine the real concentration of gold in the samples, it was used neutron activation in the nuclear reactor TRIGA MARK I IPR-R1 CDTN / CNEN of Belo Horizonte. Biocompatibility studies in vitro and in vivo of the samples were carried out showing that they have low toxicity in the models used. We evaluated

Diffuse reflectance spectroscopy as a tool for real-time tissue assessment during colorectal cancer surgery

Science.gov (United States)

Baltussen, Elisabeth J. M.; Snaebjornsson, Petur; de Koning, Susan G. Brouwer; Sterenborg, Henricus J. C. M.; Aalbers, Arend G. J.; Kok, Niels; Beets, Geerard L.; Hendriks, Benno H. W.; Kuhlmann, Koert F. D.; Ruers, Theo J. M.

2017-10-01

Colorectal surgery is the standard treatment for patients with colorectal cancer. To overcome two of the main challenges, the circumferential resection margin and postoperative complications, real-time tissue assessment could be of great benefit during surgery. In this ex vivo study, diffuse reflectance spectroscopy (DRS) was used to differentiate tumor tissue from healthy surrounding tissues in patients with colorectal neoplasia. DRS spectra were obtained from tumor tissue, healthy colon, or rectal wall and fat tissue, for every patient. Data were randomly divided into training (80%) and test (20%) sets. After spectral band selection, the spectra were classified using a quadratic classifier and a linear support vector machine. Of the 38 included patients, 36 had colorectal cancer and 2 had an adenoma. When the classifiers were applied to the test set, colorectal cancer could be discriminated from healthy tissue with an overall accuracy of 0.95 (±0.03). This study demonstrates the possibility to separate colorectal cancer from healthy surrounding tissue by applying DRS. High classification accuracies were obtained both in homogeneous and inhomogeneous tissues. This is a fundamental step toward the development of a tool for real-time in vivo tissue assessment during colorectal surgery.

Metabolite characterization in serum samples from normal healthy ...

African Journals Online (AJOL)

Metabolite characterization in serum samples from normal healthy human subjects by 1H and 13C NMR spectroscopy. D Misra, U Bajpai. Abstract. One and two dimensional NMR spectroscopy has been employed to characterize the various metabolites of serum control healthy samples. Two dimensional heteronuclear ...

Thermal and Chemical Characterization of Non-Metallic Materials Using Coupled Thermogravimetric Analysis and Infrared Spectroscopy

Science.gov (United States)

Huff, Timothy L.

2002-01-01

Thermogravimetric analysis (TGA) is widely employed in the thermal characterization of non-metallic materials, yielding valuable information on decomposition characteristics of a sample over a wide temperature range. However, a potential wealth of chemical information is lost during the process, with the evolving gases generated during thermal decomposition escaping through the exhaust line. Fourier Transform-Infrared spectroscopy (FT-IR) is a powerful analytical technique for determining many chemical constituents while in any material state, in this application, the gas phase. By linking these two techniques, evolving gases generated during the TGA process are directed into an appropriately equipped infrared spectrometer for chemical speciation. Consequently, both thermal decomposition and chemical characterization of a material may be obtained in a single sample run. In practice, a heated transfer line is employed to connect the two instruments while a purge gas stream directs the evolving gases into the FT-IR. The purge gas can be either high purity air or an inert gas such as nitrogen to allow oxidative and pyrolytic processes to be examined, respectively. The FT-IR data is collected realtime, allowing continuous monitoring of chemical compositional changes over the course of thermal decomposition. Using this coupled technique, an array of diverse materials has been examined, including composites, plastics, rubber, fiberglass epoxy resins, polycarbonates, silicones, lubricants and fluorocarbon materials. The benefit of combining these two methodologies is of particular importance in the aerospace community, where newly developing materials have little available data with which to refer. By providing both thermal and chemical data simultaneously, a more definitive and comprehensive characterization of the material is possible. Additionally, this procedure has been found to be a viable screening technique for certain materials, with the generated data useful in

Metabonomics of human fecal extracts characterize ulcerative colitis, Crohn's disease and healthy individuals

DEFF Research Database (Denmark)

Bjerrum, Jacob Tveiten; Wang, Yulan; Hao, Fuhua

2015-01-01

This study employs spectroscopy-based metabolic profiling of fecal extracts from healthy subjects and patients with active or inactive ulcerative colitis (UC) and Crohn's disease (CD) to substantiate the potential use of spectroscopy as a non-invasive diagnostic tool and to characterize the fecal......-projection to latent structure-discriminant analysis using SIMCA-P + 12 and MATLAB. Significant differences were found in the metabolic profiles making it possible to differentiate between active IBD and controls and between UC and CD. The metabolites holding differential power primarily belonged to a range of amino...... acids, microbiota-related short chain fatty acids, and lactate suggestive of an inflammation-driven malabsorption and dysbiosis of the normal bacterial ecology. However, removal of patients with intestinal surgery and anti-TNF-α antibody treatment eliminated the discriminative power regarding UC versus...

Mechanical Spectroscopy: Some Applications On Structural Changes And Relaxation Dynamics In Soft Matter

Directory of Open Access Journals (Sweden)

Wu Xuebang

2015-09-01

Full Text Available The general trend in soft matter is to study systems of increasing complexity covering a wide range in time and frequency. Mechanical spectroscopy is a powerful tool for understanding the structure and relaxation dynamics of these materials over a large temperature range and frequency scale. In this work, we collect a few recent applications using low-frequency mechanical spectroscopy for elucidating the structural changes and relaxation dynamics in soft matter, largely based on the author’s group. We illustrate the potential of mechanical spectroscopy with three kinds of soft materials: colloids, polymers and granular systems. Examples include structural changes in colloids, segmental relaxations in amorphous polymers, and resonant dissipation of grain chains in three-dimensional media. The present work shows that mechanical spectroscopy has been applied as a necessary and complementary tool to study the dynamics of such complex systems.

Characterization of laser-induced breakdown spectroscopy (LIBS) for application to space exploration

International Nuclear Information System (INIS)

Knight, Andrew K.; Scherbarth, Nancy L.; Cremers, David A.; Ferris, Monty J.

2000-01-01

Early in the next century, several space missions are planned with the goal of landing craft on asteroids, comets, the Moon, and Mars. To increase the scientific return of these missions, new methods are needed to provide (1) significantly more analyses per mission lifetime, and (2) expanded analytical capabilities. One method that has the potential to meet both of these needs for the elemental analysis of geological samples is laser-induced breakdown spectroscopy (LIBS). These capabilities are possible because the laser plasma provides rapid analysis and the laser pulse can be focused on a remotely located sample to perform a stand-off measurement. Stand-off is defined as a distance up to 20 m between the target and laser. Here we present the results of a characterization of LIBS for the stand-off analysis of soils at reduced air pressures and in a simulated Martian atmosphere (5-7 torr pressure of CO 2 ) showing the feasibility of LIBS for space exploration. For example, it is demonstrated that an analytically useful laser plasma can be generated at distances up to 19 m by using only 35 mJ/pulse from a compact laser. Some characteristics of the laser plasma at reduced pressure were also investigated. Temporally and spectrally resolved imaging showed significant changes in the plasma as the pressure was reduced and also showed that the analyte signals and mass ablated from a target were strongly dependent on pressure. As the pressure decreased from 590 torr to the 40-100 torr range, the signals increased by a factor of about 3-4, and as the pressure was further reduced the signals decreased. This behavior can be explained by pressure-dependent changes in the mass of material vaporized and the frequency of collisions between species in the plasma. Changes in the temperature and the electron density of the plasmas with pressure were also examined and detection limits for selected elements were determined. (c) 2000 Society for Applied Spectroscopy

Characterization of laser-induced breakdown spectroscopy (LIBS) for application to space exploration

Energy Technology Data Exchange (ETDEWEB)

Knight, Andrew K. [Group CST-1, MS J565, Chemical Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Scherbarth, Nancy L. [Group CST-1, MS J565, Chemical Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Cremers, David A. [Group CST-1, MS J565, Chemical Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ferris, Monty J. [Group CST-1, MS J565, Chemical Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2000-03-01

Early in the next century, several space missions are planned with the goal of landing craft on asteroids, comets, the Moon, and Mars. To increase the scientific return of these missions, new methods are needed to provide (1) significantly more analyses per mission lifetime, and (2) expanded analytical capabilities. One method that has the potential to meet both of these needs for the elemental analysis of geological samples is laser-induced breakdown spectroscopy (LIBS). These capabilities are possible because the laser plasma provides rapid analysis and the laser pulse can be focused on a remotely located sample to perform a stand-off measurement. Stand-off is defined as a distance up to 20 m between the target and laser. Here we present the results of a characterization of LIBS for the stand-off analysis of soils at reduced air pressures and in a simulated Martian atmosphere (5-7 torr pressure of CO{sub 2}) showing the feasibility of LIBS for space exploration. For example, it is demonstrated that an analytically useful laser plasma can be generated at distances up to 19 m by using only 35 mJ/pulse from a compact laser. Some characteristics of the laser plasma at reduced pressure were also investigated. Temporally and spectrally resolved imaging showed significant changes in the plasma as the pressure was reduced and also showed that the analyte signals and mass ablated from a target were strongly dependent on pressure. As the pressure decreased from 590 torr to the 40-100 torr range, the signals increased by a factor of about 3-4, and as the pressure was further reduced the signals decreased. This behavior can be explained by pressure-dependent changes in the mass of material vaporized and the frequency of collisions between species in the plasma. Changes in the temperature and the electron density of the plasmas with pressure were also examined and detection limits for selected elements were determined. (c) 2000 Society for Applied Spectroscopy.

Micromechanical String Resonators: Analytical Tool for Thermal Characterization of Polymers

DEFF Research Database (Denmark)

Bose, Sanjukta; Schmid, Silvan; Larsen, Tom

2014-01-01

Resonant microstrings show promise as a new analytical tool for thermal characterization of polymers with only few nanograms of sample. The detection of the glass transition temperature (Tg) of an amorphous poly(d,l-lactide) (PDLLA) and a semicrystalline poly(l-lactide) (PLLA) is investigated....... The polymers are spray coated on one side of the resonating microstrings. The resonance frequency and quality factor (Q) are measured simultaneously as a function of temperature. Change in the resonance frequency reflects a change in static tensile stress, which yields information about the Young’s modulus...... of the polymer, and a change in Q reflects the change in damping of the polymer-coated string. The frequency response of the microstring is validated with an analytical model. From the frequency independent tensile stress change, static Tg values of 40.6 and 57.6 °C were measured for PDLLA and PLLA, respectively...

Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane—Breath Biomarkers of Serious Diseases

Science.gov (United States)

Wojtas, Jacek

2015-01-01

The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases. PMID:26091398

Spectroscopy in catalysis : an introduction

NARCIS (Netherlands)

Niemantsverdriet, J.W.

2007-01-01

Spectroscopy in Catalysis is an introduction to the most important analytical techniques that are nowadays used in catalysis and in catalytic surface chemistry. The aim of the book is to give the reader a feeling for the type of information that characterization techniques provide about questions

Preparation and characterization of standardized pomegranate extract-phospholipid complex as an effective drug delivery tool

Directory of Open Access Journals (Sweden)

Amisha Kamlesh Vora

2015-01-01

Full Text Available Punicalagins, a pair of anomeric ellagitannins, present in Punica granatum (Pomegranates are known to possess excellent antioxidant activity in vitro, but poor oral bioavailability. The reasons cited for poor bioavailability are their large molecular size, poor lipophilicity, and degradation by colonic microflora into less active metabolites. The objective of the present research work was to complex the standardized pomegranate extract (SPE with phospholipid to formulate standardized pomegranate extract-phospholipid complex (SPEPC, characterize it and check its permeability through an ex vivo everted gut sac experiment. SPEPC was prepared by mixing SPE (30% punicalagins and soya phosphatidylcholine (PC in 1:1 v/v mixture of methanol and dioxane and spray-drying the mixture. The complex was characterized by infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. It was evaluated for its octanol solubility, dissolution, and permeability by everted the gut sac technique. The characterization methods confirmed the formation of complex. Increased n-octanol solubility of the complex proved its increased lipophilicity. Dissolution studies revealed that the phospholipid covering may prevent the punicalagins to be released in gastro-intestinal tract, thus preventing their colonic microbial degradation. SPEPC showed better apparent permeability than SPE in an everted gut sac technique. Hence, it could be concluded that phospholipid complex of SPE may be of potential use in increasing the permeability and hence the bioavailability of punicalagins.

Comparison of torque measurements and near-infrared spectroscopy in characterization of a wet granulation process

DEFF Research Database (Denmark)

Jørgensen, Anna Cecilia; Luukkonen, Pirjo; Rantanen, Jukka

2004-01-01

The purpose of this study was to compare impeller torque measurements and near-infrared (NIR) spectroscopy in the characterization of the water addition phase of a wet granulation process. Additionally, the effect of hydrate formation during granulation on the impeller torque was investigated....... Anhydrous theophylline, alpha-lactose monohydrate, and microcrystalline cellulose (MCC) were used as materials for the study. The materials and mixtures of them were granulated using purified water in a small-scale high-shear mixer. The impeller torque was registered and NIR spectra of wet samples were...... recorded at-line. The torque and the NIR baseline-corrected water absorbances increased with increasing water content. A plateau in the NIR baseline-corrected water absorbances was observed for wet masses containing MCC. This was at the region of optimal water amount for granulation according to the torque...

Post-Kerr black hole spectroscopy

Science.gov (United States)

Glampedakis, Kostas; Pappas, George; Silva, Hector O.; Berti, Emanuele

2017-09-01

One of the central goals of the newborn field of gravitational wave astronomy is to test gravity in the highly nonlinear, strong field regime characterizing the spacetime of black holes. In particular, "black hole spectroscopy" (the observation and identification of black hole quasinormal mode frequencies in the gravitational wave signal) is expected to become one of the main tools for probing the structure and dynamics of Kerr black holes. In this paper we take a significant step toward that goal by constructing a "post-Kerr" quasinormal mode formalism. The formalism incorporates a parametrized but general perturbative deviation from the Kerr metric and exploits the well-established connection between the properties of the spacetime's circular null geodesics and the fundamental quasinormal mode to provide approximate, eikonal limit formulas for the modes' complex frequencies. The resulting algebraic toolkit can be used in waveform templates for ringing black holes with the purpose of measuring deviations from the Kerr metric. As a first illustrative application of our framework, we consider the Johannsen-Psaltis deformed Kerr metric and compute the resulting deviation in the quasinormal mode frequency relative to the known Kerr result.

Raman spectroscopy as a tool to investigate the structure and electronic properties of carbon-atom wires

Directory of Open Access Journals (Sweden)

Alberto Milani

2015-02-01

Full Text Available Graphene, nanotubes and other carbon nanostructures have shown potential as candidates for advanced technological applications due to the different coordination of carbon atoms and to the possibility of π-conjugation. In this context, atomic-scale wires comprised of sp-hybridized carbon atoms represent ideal 1D systems to potentially downscale devices to the atomic level. Carbon-atom wires (CAWs can be arranged in two possible structures: a sequence of double bonds (cumulenes, resulting in a 1D metal, or an alternating sequence of single–triple bonds (polyynes, expected to show semiconducting properties. The electronic and optical properties of CAWs can be finely tuned by controlling the wire length (i.e., the number of carbon atoms and the type of termination (e.g., atom, molecular group or nanostructure. Although linear, sp-hybridized carbon systems are still considered elusive and unstable materials, a number of nanostructures consisting of sp-carbon wires have been produced and characterized to date. In this short review, we present the main CAW synthesis techniques and stabilization strategies and we discuss the current status of the understanding of their structural, electronic and vibrational properties with particular attention to how these properties are related to one another. We focus on the use of vibrational spectroscopy to provide information on the structural and electronic properties of the system (e.g., determination of wire length. Moreover, by employing Raman spectroscopy and surface enhanced Raman scattering in combination with the support of first principles calculations, we show that a detailed understanding of the charge transfer between CAWs and metal nanoparticles may open the possibility to tune the electronic structure from alternating to equalized bonds.

Surface characterization of ceramic materials

International Nuclear Information System (INIS)

Somorjai, G.A.; Salmeron, M.

1976-01-01

In recent years several techniques have become available to characterize the structure and chemical composition of surfaces of ceramic materials. These techniques utilize electron scattering and scattering of ions from surfaces. Low-energy electron diffraction is used to determine the surface structure, Auger electron spectroscopy and other techniques of electron spectroscopy (ultraviolet and photoelectron spectroscopies) are employed to determine the composition of the surface. In addition the oxidation state of surface atoms may be determined using these techniques. Ion scattering mass spectrometry and secondary ion mass spectrometry are also useful in characterizing surfaces and their reactions. These techniques, their applications and the results of recent studies are discussed. 12 figures, 52 references, 2 tables

Impedance Spectroscopy of Dielectrics and Electronic Conductors

DEFF Research Database (Denmark)

Bonanos, Nikolaos; Pissis, Polycarpos; Macdonald, J. Ross

2013-01-01

Impedance spectroscopy is used for the characterization of materials, such as electroceramics, solid and liquid electrochemical cells, dielectrics and also fully integrated devices, such as fuel cells. It consists of measuring the electrical impedance - or a closely related property, such as admi......Impedance spectroscopy is used for the characterization of materials, such as electroceramics, solid and liquid electrochemical cells, dielectrics and also fully integrated devices, such as fuel cells. It consists of measuring the electrical impedance - or a closely related property......, such as admittance or dielectric constant - as a function of frequency and comparing the results with expectations based on physical, chemical, and microstructural models. This article reviews the principles and practical aspects of the technique, the representations of the results, the analysis of data......, and procedures for the correction of measurement errors. The applications of impedance spectroscopy are illustrated with examples from electroceramics and polymer-based dielectric systems. The way in which the technique is applied to the two classes of materials is compared with reference to the different models...

Characterization and noninvasive diagnosis of bladder cancer with serum surface enhanced Raman spectroscopy and genetic algorithms

Science.gov (United States)

Li, Shaoxin; Li, Linfang; Zeng, Qiuyao; Zhang, Yanjiao; Guo, Zhouyi; Liu, Zhiming; Jin, Mei; Su, Chengkang; Lin, Lin; Xu, Junfa; Liu, Songhao

2015-05-01

This study aims to characterize and classify serum surface-enhanced Raman spectroscopy (SERS) spectra between bladder cancer patients and normal volunteers by genetic algorithms (GAs) combined with linear discriminate analysis (LDA). Two group serum SERS spectra excited with nanoparticles are collected from healthy volunteers (n = 36) and bladder cancer patients (n = 55). Six diagnostic Raman bands in the regions of 481-486, 682-687, 1018-1034, 1313-1323, 1450-1459 and 1582-1587 cm-1 related to proteins, nucleic acids and lipids are picked out with the GAs and LDA. By the diagnostic models built with the identified six Raman bands, the improved diagnostic sensitivity of 90.9% and specificity of 100% were acquired for classifying bladder cancer patients from normal serum SERS spectra. The results are superior to the sensitivity of 74.6% and specificity of 97.2% obtained with principal component analysis by the same serum SERS spectra dataset. Receiver operating characteristic (ROC) curves further confirmed the efficiency of diagnostic algorithm based on GA-LDA technique. This exploratory work demonstrates that the serum SERS associated with GA-LDA technique has enormous potential to characterize and non-invasively detect bladder cancer through peripheral blood.

Piezomodulated reflectivity on CdMnTe/CdTe quantum well structures as a new standard characterization method

Energy Technology Data Exchange (ETDEWEB)

Kurtz, E.; Schmitt, K.; Hommel, D.; Waag, A.; Bicknell-Tassius, R.N.; Landwehr, G. (Physikalisches Inst., Univ. Wuerzburg (Germany))

1993-01-30

Piezomodulated reflectivity (PZR) measurements are reported for the first time as a standard characterization method for CdMnTe/CdTe single (SQW) and multiple (MQW) quantum wells grown by molecular beam epitaxy on CdTe substrates 1 mm thick. Previously, modulation spectroscopy studies of II-VI structures required thin substrates which needed special preparation. In this paper we present studies of optical properties of CdMnTe/CdTe SQWs and MWQs using the PZR technique. The samples, mounted on a sinusoidally driven piezoelectric transducer are subjected to an alternating strain. Exploiting ''lock-in'' techniques, the first derivative of the reflectivity is measured directly. Specific electronic transitions, e.g. excitons, are well resolved in the modulated spectrum and can be easily identified. This makes PZR a very sensitive and powerful tool for the characterization of quantum well structures, and a useful complement to other standard techniques such as photoluminescence and excitation spectroscopy. (orig.).

Review of x-ray spectroscopy from laser-produced plasmas

International Nuclear Information System (INIS)

Kauffman, R.L.

1987-09-01

Recent progress in x-ray spectroscopy from laser plasmas is reviewed. Advances in the use of K-shell spectra as a diagnostic tool is discussed. Much activity in understanding complex spectra especially from Ne I and Ni I isoelectronic series have been made. Much of the progress has been due to observation of amplification from Δn = O transitions from these configurations. The spectroscopy will be discussed and examples of spectra of the amplified lines will be shown. Finally, recent work on using x-ray spectroscopy to diagnose high density implosions will be discussed. 33 refs

Applications of spectroscopy with multiwavelength sources

NARCIS (Netherlands)

Hänsel, A.

2018-01-01

Spectroscopy is a powerful tool to investigate the physical properties of complex systems. The interaction of light with matter allows to get insights into the structure of it. Chapter 1 is dedicated to introduce this topic and to show the developments of the technologies that paved the way to its

Characterization of the Pore Filling of Solid State Dye Sensitized Solar Cells with Photoinduced Absorption Spectroscopy

Directory of Open Access Journals (Sweden)

Carol Olson

2011-01-01

Full Text Available Near steady-state photoinduced absorption (PIA and UV-Vis absorption spectroscopy are used to characterize the pore filling of spiro-MeOTAD (2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine9,9′-spirobifluorene into the nanoparticulate TiO2 electrode of a solid-state dye-sensitized solar cell (ssDSC. The volumetric ratio of filled to unfilled pore volumes, as well as the optical signature of interacting chemical species, that is, the hole-transfer yield (HTY, are investigated. PIA spectroscopy is used to measure the HTY, relative to the amount of spiro-MeOTAD present, without needing to determine the extinction coefficients of the dye and spiro-MeOTAD cation species. The Beer-Lambert law is used to relate the relative PIA signal to the penetration length of the hole-conductor in the TiO2 film. For the sample thickness range of 1.4–5 μm investigated here, the optimum characteristic penetration length is determined to be 3.1+0.46 μm, which is compared to 1.4 μm for the 200 mg mL−1 concentration of spiro-MeOTAD conventionally used. Therefore, doubling the effective penetration of spiro-MeOTAD is necessary to functionalize all the dye molecules in a ssDSC.

Characterization of Roman glass tesserae from the Coriglia excavation site (Italy) via energy-dispersive X-ray fluorescence spectrometry and Raman spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Donais, Mary Kate; Sparks, Andrew; Redente, Monica [Saint Anselm College, Department of Chemistry, Manchester, NH (United States); Pevenage, Jolien van; Moens, Luc; Vincze, Laszlo [Ghent University, Department of Analytical Chemistry, Ghent (Belgium); George, David B. [Saint Anselm College, Department of Classics, Manchester, NH (United States); Vandenabeele, Peter [Ghent University, Department of Archaeology, Ghent (Belgium)

2016-12-15

The combined use of handheld energy-dispersive X-ray fluorescence spectrometry, Raman spectroscopy, and micro-energy-dispersive X-ray fluorescence spectrometry permitted the characterization of Roman glass tesserae excavation from the Coriglia (Italy) archeological site. Analyses of ten different glass colors were conducted as spot analyses on intact samples and as both spot analyses and line scans on select cross-sectioned samples. The elemental and molecular information gained from these spectral measurements allowed for the qualitative chemical characterization of the bulk glass, decolorants, opacifiers, and coloring agents. The use of an antimony opacifier in many of the samples supports the late Imperial phasing as determined through numismatic, fresco, ceramics, and architectural evidence. And dealinization of the exterior glass layers caused by the burial environment was confirmed. (orig.)

Transgenic tools to characterize neuronal properties of discrete populations of zebrafish neurons.

Science.gov (United States)

Satou, Chie; Kimura, Yukiko; Hirata, Hiromi; Suster, Maximiliano L; Kawakami, Koichi; Higashijima, Shin-ichi

2013-09-01

The developing nervous system consists of a variety of cell types. Transgenic animals expressing reporter genes in specific classes of neuronal cells are powerful tools for the study of neuronal network formation. We generated a wide variety of transgenic zebrafish that expressed reporter genes in specific classes of neurons or neuronal progenitors. These include lines in which neurons of specific neurotransmitter phenotypes expressed fluorescent proteins or Gal4, and lines in which specific subsets of the dorsal progenitor domain in the spinal cord expressed fluorescent proteins. Using these, we examined domain organization in the developing dorsal spinal cord, and found that there are six progenitor domains in zebrafish, which is similar to the domain organization in mice. We also systematically characterized neurotransmitter properties of the neurons that are produced from each domain. Given that reporter gene expressions occurs in a wide area of the nervous system in the lines generated, these transgenic fish should serve as powerful tools for the investigation of not only the neurons in the dorsal spinal cord but also neuronal structures and functions in many other regions of the nervous system.

Wild 2 grains characterized combining MIR/FIR/Raman micro-spectroscopy and FE-SEM/EDS analyses

Science.gov (United States)

Ferrari, M.; Rotundi, A.; Rietmeijer, F. J. M.; Della Corte, V.; Baratta, G. A.; Brunetto, R.; Dartois, E.; Djouadi, Z.; Merouane, S.; Borg, J.; Brucato, J. R.; Le Sergeant d'Hendecourt, L.; Mennella, V.; Palumbo, M. E.; Palumbo, P.

We present the results of the analyses \\cite{Rotundi14} of two bulk terminal particles (TPs), C2112,7,171,0,0 (TP2) and C2112,9,171,0,0 (TP3), derived from the Jupiter-Family comet 81P/Wild 2 returned by the NASA Stardust mission \\cite{Brownlee06}. Each particle, embedded in a slab of silica aerogel, was pressed in a diamond cell. Aerogel is usually cause of problems when characterizing the minerals and organic materials present in the embedded particles. We overcame this common issue by means of the combination of FE-SEM/EDS, IR and Raman mu -spectroscopy, three non-destructive analytical techniques, which provided bulk mineralogical and organic information on TP2 and TP3. This approach proved to be a practical solution for preliminary characterization, i.e. scanning particles for chemical and mineralogical heterogeneity. Using this type of bulk characterization prior to more detailed studies, could be taken into account as a standard procedure to be followed for selecting Stardust particles-of-interest. TP2 and TP3 are dominated by Ca-free and low-Ca, Mg-rich, Mg,Fe-olivine. The presence of melilite in both particles is supported by IR mu -spectroscopy and corroborated by FE-SEM/EDS analyses, but is not confirmed by Raman mu -spectroscopy possibly because the amount of this mineral is too small to be detected. TP2 and TP3 show similar silicate mineral compositions, but Ni-free, low-Ni, sub-sulfur (Fe,Ni)S grains are present only in TP2. TP2 contains indigenous amorphous carbon hot spots, while no indigenous carbon was identified in TP3. These non-chondritic particles probably originated in a differentiated body. The presence of high temperature melilite group minerals (incl. gehlenite) in TP2 and TP3 reinforces the notion that collisionally-ejected refractory debris from differentiated asteroids may be common in Jupiter-Family comets. This raises the question whether similar debris and other clearly asteroidal particles could be present in Halley-type comets

Application of fluorescence spectroscopy for dissolved organic matter characterization in constructed wetlands

Science.gov (United States)

Sardana, A.; Aziz, T. N.; Cottrell, B. A.

2017-12-01

In this presentation we will discuss our ongoing work to characterize the photochemical behavior of dissolved organic matter (DOM) from wastewater treated in constructed wetlands. We have used a suite of spectroscopic and chromatographic techniques to characterize the DOM and to quantify the potential production of reactive oxygenated species (ROS). In the present study, DOM was fractionated based on its hydrophobicity and both the natural water isolates and fractionated DOM were characterized using SUVA254, spectral slope ratios, excitation emission matrix fluorescence spectroscopy (EEMs) and proton nuclear magnetic resonance (1H NMR). Photodegradation of wetland DOM and the formation of the hydroxyl radical (*OH), singlet oxygen (1O2), and the triplet-excited state (3DOM*) was also determined to assess the reactivity of DOM. EEM spectra exhibited the four main fluorescence peaks that are characteristic of DOM: peak A humic-like DOM, Peak C (fulvic or chromophoric DOM), Peak M (marine-like DOM), and peak T (tryptophan or protein-like absorbance). Two additional observed peaks with shorter emission wavelengths (A' Ex/Em = 243/278 nm and T' Ex/Em = 272/319 nm) were attributed to the microbial DOM in wastewater effluent. The spectral slope ratios decreased from 1.46 at the wetland inlet to 0.89 at the wetland outlet. The protein-like Peak T fluorescence decreased from 50% at the wetland inlet to 6.7% at the Wetland 2 outlet. A negative correlation between the percent fluorescence of Peak T and Peaks A, C and M confirmed the transition from the spectrum of pure wastewater with a primarily protein-like signature to a spectrum characteristic of terrestrially derived DOM. This transition coincided with enhanced formation rates and steady state concentrations of photochemically produced reactive intermediates (PPRIs). Size Exclusion Chromatography demonstrated that the influent wastewater had a lower molecular weight as compared to downstream wetland locations

Emerging applications of fluorescence spectroscopy in medical microbiology field.

Science.gov (United States)

Shahzad, Aamir; Köhler, Gottfried; Knapp, Martin; Gaubitzer, Erwin; Puchinger, Martin; Edetsberger, Michael

2009-11-26

There are many diagnostic techniques and methods available for diagnosis of medically important microorganisms like bacteria, viruses, fungi and parasites. But, almost all these techniques and methods have some limitations or inconvenience. Most of these techniques are laborious, time consuming and with chances of false positive or false negative results. It warrants the need of a diagnostic technique which can overcome these limitations and problems. At present, there is emerging trend to use Fluorescence spectroscopy as a diagnostic as well as research tool in many fields of medical sciences. Here, we will critically discuss research studies which propose that Fluorescence spectroscopy may be an excellent diagnostic as well as excellent research tool in medical microbiology field with high sensitivity and specificity.

Emerging applications of fluorescence spectroscopy in medical microbiology field

Directory of Open Access Journals (Sweden)

Gaubitzer Erwin

2009-11-01

Full Text Available Abstract There are many diagnostic techniques and methods available for diagnosis of medically important microorganisms like bacteria, viruses, fungi and parasites. But, almost all these techniques and methods have some limitations or inconvenience. Most of these techniques are laborious, time consuming and with chances of false positive or false negative results. It warrants the need of a diagnostic technique which can overcome these limitations and problems. At present, there is emerging trend to use Fluorescence spectroscopy as a diagnostic as well as research tool in many fields of medical sciences. Here, we will critically discuss research studies which propose that Fluorescence spectroscopy may be an excellent diagnostic as well as excellent research tool in medical microbiology field with high sensitivity and specificity.

Characterization of extra-solar planets and their atmospheres (Spectroscopy of transits and atmospheric escape)

International Nuclear Information System (INIS)

Bourrier, Vincent

2014-01-01

Hot Jupiters are exo-planets so close to their star that their atmosphere can lose gas because of hydrodynamic escape. Transiting gaseous giants are an excellent way to understand this mechanism, but it is necessary to study other types of planets to determine its impact on the exo-planetary population. This thesis aims at using transit spectroscopy to observe the atmosphere of several exo-planets, to study their properties and to contribute to the characterization of hydrodynamic escape. UV lines observed with the Hubble telescope are analyzed with the numerical model of upper atmospheres we developed. Using the Ly-α line we identify energetic and dynamical interactions between the atmospheres of the hot Jupiters HD209458b and HD189733b and their stars. We study the dependence of the escape on the environment of a planet and on its physical properties, through the observation of a super-Earth and a warm Jupiter in the 55 Cnc system. Using observations of HD209458b, we show that magnesium lines are a window on the region of formation of hydrodynamic escape. We study the potential of transit spectroscopy in the near-UV to detect new cases of atmospheric escape. This mechanism is fostered by the proximity of a planet to its star, which makes it even more important to understand the formation and migration processes that can be traced in the alignment of a planetary system. Using measures from the spectrographs HARPS-N and SOPHIE we study the alignments of 55 Cnc e and the Kepler candidate KOI 12.01, whose planetary nature we also seek to validate. (author)

XAFS Spectroscopy : Fundamental Principles and Data Analysis

NARCIS (Netherlands)

Koningsberger, D.C.; Mojet, B.L.; Dorssen, G.E. van; Ramaker, D.E.

2000-01-01

The physical principles of XAFS spectroscopy are given at a sufficiently basic level to enable scientists working in the field of catalysis to critically evaluate articles dealing with XAFS studies on catalytic materials. The described data-analysis methods provide the basic tools for studying the

Vibrational spectroscopy: a tool being developed for the noninvasive monitoring of wound healing

Science.gov (United States)

Crane, Nicole J.; Elster, Eric A.

2012-01-01

Wound care and management accounted for over 1.8 million hospital discharges in 2009. The complex nature of wound physiology involves hundreds of overlapping processes that we have only begun to understand over the past three decades. The management of wounds remains a significant challenge for inexperienced clinicians. The ensuing inflammatory response ultimately dictates the pace of wound healing and tissue regeneration. Consequently, the eventual timing of wound closure or definitive coverage is often subjective. Some wounds fail to close, or dehisce, despite the use and application of novel wound-specific treatment modalities. An understanding of the molecular environment of acute and chronic wounds throughout the wound-healing process can provide valuable insight into the mechanisms associated with the patient's outcome. Pathologic alterations of wounds are accompanied by fundamental changes in the molecular environment that can be analyzed by vibrational spectroscopy. Vibrational spectroscopy, specifically Raman and Fourier transform infrared spectroscopy, offers the capability to accurately detect and identify the various molecules that compose the extracellular matrix during wound healing in their native state. The identified changes might provide the objective markers of wound healing, which can then be integrated with clinical characteristics to guide the management of wounds.

Combined In Situ Illumination-NMR-UV/Vis Spectroscopy: A New Mechanistic Tool in Photochemistry.

Science.gov (United States)

Seegerer, Andreas; Nitschke, Philipp; Gschwind, Ruth M

2018-06-18

Synthetic applications in photochemistry are booming. Despite great progress in the development of new reactions, mechanistic investigations are still challenging. Therefore, we present a fully automated in situ combination of NMR spectroscopy, UV/Vis spectroscopy, and illumination to allow simultaneous and time-resolved detection of paramagnetic and diamagnetic species. This optical fiber-based setup enables the first acquisition of combined UV/Vis and NMR spectra in photocatalysis, as demonstrated on a conPET process. Furthermore, the broad applicability of combined UVNMR spectroscopy for light-induced processes is demonstrated on a structural and quantitative analysis of a photoswitch, including rate modulation and stabilization of transient species by temperature variation. Owing to the flexibility regarding the NMR hardware, temperature, and light sources, we expect wide-ranging applications of this setup in various research fields. © 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

International Nuclear Information System (INIS)

Bonomo, F.; Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D.; Barbisan, M.; Pasqualotto, R.; Serianni, G.; Cristofaro, S.

2015-01-01

The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H α light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H α spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region

Application of Laser Induced Breakdown Spectroscopy under Polar Conditions

Science.gov (United States)

Clausen, J. L.; Hark, R.; Bol'shakov, A.; Plumer, J.

2015-12-01

Over the past decade our research team has evaluated the use of commercial-off-the-shelf laser-induced breakdown spectroscopy (LIBS) for chemical analysis of snow and ice samples under polar conditions. One avenue of research explored LIBS suitability as a detector of paleo-climate proxy indicators (Ca, K, Mg, and Na) in ice as it relates to atmospheric circulation. LIBS results revealed detection of peaks for C and N, consistent with the presence of organic material, as well as major ions (Ca, K, Mg, and Na) and trace metals (Al, Cu, Fe, Mn, Ti). The detection of Ca, K, Mg, and Na confirmed that LIBS has sufficient sensitivity to be used as a tool for characterization of paleo-climate proxy indicators in ice-core samples. Techniques were developed for direct analysis of ice as well as indirect measurements of ice via melting and filtering. Pitfalls and issues of direct ice analysis using several cooling techniques to maintain ice integrity will be discussed. In addition, a new technique, laser ablation molecular isotopic spectroscopy (LAMIS) was applied to detection of hydrogen and oxygen isotopes in ice as isotopic analysis of ice is the main tool in paleoclimatology and glaciology studies. Our results demonstrated that spectra of hydroxyl isotopologues 16OH, 18OH, and 16OD can be recorded with a compact spectrograph to determine hydrogen and oxygen isotopes simultaneously. Quantitative isotopic calibration for ice analysis can be accomplished using multivariate chemometric regression as previously realized for water vapor. Analysis with LIBS and LAMIS required no special sample preparation and was about ten times faster than analysis using ICP-MS. Combination of the two techniques in one portable instrument for in-field analysis appears possible and would eliminate the logistical and cost issues associated with ice core management.

Layman friendly spectroscopy

Science.gov (United States)

Sentic, Stipo; Sessions, Sharon

Affordable consumer grade spectroscopes (e.g. SCiO, Qualcomm Tricorder XPRIZE) are becoming more available to the general public. We introduce the concepts of spectroscopy to the public and K12 students and motivate them to delve deeper into spectroscopy in a dramatic participatory presentation and play. We use diffraction gratings, lasers, and light sources of different spectral properties to provide a direct experience of spectroscopy techniques. Finally, we invite the audience to build their own spectroscope--utilizing the APS SpectraSnapp cell phone application--and study light sources surrounding them in everyday life. We recontextualize the stigma that science is hard (e.g. ``Math, Science Popular Until Students Realize They're Hard,'' The Wall Street Journal) by presenting the material in such a way that it demonstrates the scientific method, and aiming to make failure an impersonal scientific tool--rather than a measure of one's ability, which is often a reason for shying away from science. We will present lessons we have learned in doing our outreach to audiences of different ages. This work is funded by the APS Outreach Grant ``Captain, we have matter matters!'' We thank New Mexico Tech Physics Department and Physics Club for help and technical equipment.

Characterization of D2 tool steel friction surfaced coatings over low carbon steel

International Nuclear Information System (INIS)

Sekharbabu, R.; Rafi, H. Khalid; Rao, K. Prasad

2013-01-01

Highlights: • Solid state coating by friction surfacing method. • D2 tool steel is coated over relatively softer low carbon steel. • Defect free interface between tool steel coating and low carbon steel substrate. • D2 coatings exhibited higher hardness and good wear resistance. • Highly refined martensitic microstructure in the coating. - Abstract: In this work D2 tool steel coating is produced over a low carbon steel substrate using friction surfacing process. The process parameters are optimized to get a defect free coating. Microstructural characterization is carried out using optical microscopy, scanning electron microscopy and X-ray diffraction. Infrared thermography is used to measure the thermal profile during friction surfacing of D2 steel. Wear performance of the coating is studied using Pin-on-Disk wear tests. A lower rotational speed of the consumable rod and higher translational speed of the substrate is found to result in thinner coatings. Friction surfaced D2 steel coating showed fine-grained martensitic microstructure compared to the as-received consumable rod which showed predominantly ferrite microstructure. Refinement of carbides in the coating is observed due to the stirring action of the process. The infrared thermography studies showed the peak temperature attained by the D2 coating to be about 1200 °C. The combined effect of martensitic microstructure and refined carbides resulted in higher hardness and wear resistance of the coating

A high pressure x-ray photoelectron spectroscopy experimental method for characterization of solid-liquid interfaces demonstrated with a Li-ion battery system

Energy Technology Data Exchange (ETDEWEB)

Maibach, Julia; Xu, Chao; Gustafsson, Torbjörn; Edström, Kristina [Department of Chemistry–Ångström Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala (Sweden); Eriksson, Susanna K. [Department of Chemistry–Ångström Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala (Sweden); Åhlund, John [VG Scienta AB, Box 15120, SE-750 15 Uppsala (Sweden); Siegbahn, Hans; Rensmo, Håkan; Hahlin, Maria, E-mail: maria.hahlin@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden)

2015-04-15

We report a methodology for a direct investigation of the solid/liquid interface using high pressure x-ray photoelectron spectroscopy (HPXPS). The technique was demonstrated with an electrochemical system represented by a Li-ion battery using a silicon electrode and a liquid electrolyte of LiClO{sub 4} in propylene carbonate (PC) cycled versus metallic lithium. For the first time the presence of a liquid electrolyte was realized using a transfer procedure where the sample was introduced into a 2 mbar N{sub 2} environment in the analysis chamber without an intermediate ultrahigh vacuum (UHV) step in the load lock. The procedure was characterized in detail concerning lateral drop gradients as well as stability of measurement conditions over time. The X-ray photoelectron spectroscopy (XPS) measurements demonstrate that the solid substrate and the liquid electrolyte can be observed simultaneously. The results show that the solid electrolyte interphase (SEI) composition for the wet electrode is stable within the probing time and generally agrees well with traditional UHV studies. Since the methodology can easily be adjusted to various high pressure photoelectron spectroscopy systems, extending the approach towards operando solid/liquid interface studies using liquid electrolytes seems now feasible.

Multi-Instrument Characterization of the Surfaces and Materials in Microfabricated, Carbon Nanotube-Templated Thin Layer Chromatography Plates. An Analogy to ‘The Blind Men and the Elephant’

Energy Technology Data Exchange (ETDEWEB)

Jensen, David S.; Kanyal, Supriya S.; Madaan, Nitesh; Hancock, Jared M.; Dadson, Andrew; Vail, Michael A.; Vanfleet, Richard; Shutthanandan, V.; Zhu, Zihua; Engelhard, Mark H.; Linford, Matthew R.

2013-08-08

Herein we apply a suite of surface/materials analytical tools to characterize some of the materials created in the production of microfabricated thin layer chromatography plates. Techniques used include X-ray photoelectron spectroscopy (XPS), valence band spectroscopy, static time-of-flight secondary ion spectrometry (ToF-SIMS) in both positive and negative ion modes, Rutherford backscattering spectroscopy (RBS), and helium ion microscopy (HIM). Materials characterized include: the Si(100) substrate with native oxide: Si/SiO2, alumina (35 nm) deposited as a diffusion barrier on the Si/SiO2: Si/SiO2/Al2O3, iron (6 nm) thermally evaporated on the Al2O3: Si/SiO2/Al2O3/Fe, the iron film annealed in H2 to make Fe catalyst nanoparticles: Si/SiO2/Al2O3/Fe(NP), and carbon nanotubes (CNTs) grown from the Fe nanoparticles: Si/SiO2/Al2O3/Fe(NP)/CNT. The Fe thin films and nanoparticles are found in an oxidized state. Some of the analyses of the CNTs/CNT forests reported appear to be unique: the CNT forest appears to exhibit an interesting ‘channeling’ phenomenon by RBS, we observe an odd-even effect in the ToF-SIMS spectra of Cn- species for n = 1 – 6, with ions at even n showing greater intensity than the neighboring signals, and ions with n ≥ 6 showing a steady decrease in intensity, and valence band characterization of CNTs using X-radiation is reported. The information obtained from the combination of the different analytical tools provides a more complete understanding of our materials than a single technique, which is analogous to the story of ‘The Blind Men and the Elephant’. (Of course there is increasing emphasis on the use of multiple characterization tools in surface and materials analysis.) The raw XPS and ToF-SIMS spectra from this study will be submitted to Surface Science Spectra for archiving.

Threshold photoelectron spectroscopy and photoionization total ion yield spectroscopy of simple organic acids, aldehydes, ketones and amines

International Nuclear Information System (INIS)

Yencha, Andrew J; Malins, Andrew E R; Siggel-King, Michele R F; Eypper, Marie; King, George C

2009-01-01

We have initiated a research program to investigate the ionization behavior of some simple organic molecules containing the carboxyl group (R 2 C=O), where R could be H, OH, NH 2 , or CH 3 or other aliphatic or aromatic carbon groups, using threshold photoelectron spectroscopy and photoionization total ion yield spectroscopy. We report here on the simplest organic acid, formic acid, and two simple aldehydes: acetaldehyde and the simplest unsaturated aldehyde, 2-propenal (acrolein). The objective of this study was to characterize the valence cationic states of these molecules with vibrational structural resolution.

The ROSPHERE γ-ray spectroscopy array

Energy Technology Data Exchange (ETDEWEB)

Bucurescu, D.; Căta-Danil, I.; Ciocan, G.; Costache, C.; Deleanu, D.; Dima, R. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Filipescu, D. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Extreme Light Infrastructure Nuclear Physics - ELI-NP, Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Florea, N.; Ghiţă, D.G.; Glodariu, T.; Ivaşcu, M.; Lică, R.; Mărginean, N.; Mărginean, R. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Mihai, C., E-mail: cmihai@tandem.nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Negret, A.; Niţă, C.R.; Olăcel, A.; Pascu, S.; Sava, T. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); and others

2016-11-21

The ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) has been designed as a multi-detector setup dedicated to γ-ray spectroscopy studies at the Bucharest 9 MV Tandem accelerator. Consisting of up to 25 detectors (either Compton suppressed HPGe detectors or fast LaBr{sub 3}(Ce) scintillator detectors) together with a state of the art plunger device, ROSPHERE is a powerful tool for lifetime measurements using the Recoil Distance Doppler Shift (RDDS) and the in-beam Fast Electronic Scintillation Timing (FEST) methods. The array's geometry, detectors, electronics and data acquisition system are described. Selected results from the first experimental campaigns are also presented.

Applications of magnetic resonance spectroscopy for noninvasive assessment of hepatic steatosis

NARCIS (Netherlands)

van Werven, J.R.

2011-01-01

MR spectroscopy is a noninvasive technique to quantify hepatic steatosis. MR spectroscopy provides information about the chemical composition of tissues in a spectrum. Hepatic steatosis is characterized by accumulation of fat in the liver. The prevalence of hepatic steatosis is increasing due to its

Synthesis, characterization and biological activity studies of mixed ...

African Journals Online (AJOL)

The complexes were characterized using some physical techniques such as melting point, solubility, conductivity measurement and spectroscopic analyses such as UV-Visible spectroscopy, Atomic absorption spectroscopy, and Infrared spectroscopy. Based on the physical and spectroscopic results, the coordination of the ...

Electrochemical boriding and characterization of AISI D2 tool steel

International Nuclear Information System (INIS)

Sista, V.; Kahvecioglu, O.; Eryilmaz, O.L.; Erdemir, A.; Timur, S.

2011-01-01

D2 is an air-hardening tool steel and due to its high chromium content provides very good protection against wear and oxidation, especially at elevated temperatures. Boriding of D2 steel can further enhance its surface mechanical and tribological properties. Unfortunately, it has been very difficult to achieve a very dense and uniformly thick boride layers on D2 steel using traditional boriding processes. In an attempt to overcome such a deficiency, we explored the suitability and potential usefulness of electrochemical boriding for achieving thick and hard boride layers on this tool steel in a molten borax electrolyte at 850, 900, 950 and 1000 °C for durations ranging from 15 min to 1 h. The microstructural characterization and phase analysis of the resultant boride layers were performed using optical, scanning electron microscopy and X-ray diffraction methods. Our studies have confirmed that a single phase Fe 2 B layer or a composite layer consisting of FeB + Fe 2 B is feasible on the surface of D2 steel depending on the length of boriding time. The boride layers formed after shorter durations (i.e., 15 min) mainly consisted of Fe 2 B phase and was about 30 μm thick. The thickness of the layer formed in 60 min was about 60 μm and composed mainly of FeB and Fe 2 B. The cross sectional micro-hardness values of the boride layers varied between 14 and 22 GPa, depending on the phase composition.

Characterization of a magnetic trap by polarization dependent Zeeman spectroscopy

DEFF Research Database (Denmark)

Nielsen, Carsten Vandel; Lyngsøe, Jens Kristian; Thorseth, Anders

2008-01-01

This paper demonstrates a detailed experimental study of our cloverleaf magnetic trap for sodium atoms. By using polarization dependent Zeeman spectroscopy of our atomic beam, passing the magnetic trap region, we have determined important trap parameters such as gradients, their curvatures...

A simple, sensitive and non-destructive technique for characterizing bovine dental enamel erosion: attenuated total reflection Fourier transform infrared spectroscopy.

Science.gov (United States)

Kim, In-Hye; Son, Jun Sik; Min, Bong Ki; Kim, Young Kyoung; Kim, Kyo-Han; Kwon, Tae-Yub

2016-03-30

Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (Perosion.

Spec Tool; an online education and research resource

Science.gov (United States)

Maman, S.; Shenfeld, A.; Isaacson, S.; Blumberg, D. G.

2016-06-01

Education and public outreach (EPO) activities related to remote sensing, space, planetary and geo-physics sciences have been developed widely in the Earth and Planetary Image Facility (EPIF) at Ben-Gurion University of the Negev, Israel. These programs aim to motivate the learning of geo-scientific and technologic disciplines. For over the past decade, the facility hosts research and outreach activities for researchers, local community, school pupils, students and educators. As software and data are neither available nor affordable, the EPIF Spec tool was created as a web-based resource to assist in initial spectral analysis as a need for researchers and students. The tool is used both in the academic courses and in the outreach education programs and enables a better understanding of the theoretical data of spectroscopy and Imaging Spectroscopy in a 'hands-on' activity. This tool is available online and provides spectra visualization tools and basic analysis algorithms including Spectral plotting, Spectral angle mapping and Linear Unmixing. The tool enables to visualize spectral signatures from the USGS spectral library and additional spectra collected in the EPIF such as of dunes in southern Israel and from Turkmenistan. For researchers and educators, the tool allows loading collected samples locally for further analysis.

The micro and meso-porous materials. Characterization; Les materiaux micro et mesoporeux. Caracterisation

Energy Technology Data Exchange (ETDEWEB)

Thibault-Starzyk, F.

2004-10-01

The micro and meso-porous materials, called zeolites, are very important in the modern chemical industry and in petrochemistry. This book deals in particular with the study and the characterization of zeolites. Its aim is to give to generalist chemists the tools for approaching experimentally these particular materials. The main methods of study and characterization are gathered in eight chapters, and the authors stress on the specificities due to the porous system: -structural analysis by the diffraction methods; -infrared spectroscopy; -NMR; -micro-calorimetry; -adsorption thermodynamics; -methods using the programed temperature; -modeling; -reactivity: kinetics and chemical engineering. This book appeals to students, engineers or searchers, without previous knowledge on these materials, but having a bachelor's degree or a master degree in general chemistry. (O.M.)

XPS Protocol for the Characterization of Pristine and Functionalized Single Wall Carbon Nanotubes

Science.gov (United States)

Sosa, E. D.; Allada, R.; Huffman, C. B.; Arepalli, S.

2009-01-01

Recent interest in developing new applications for carbon nanotubes (CNT) has fueled the need to use accurate macroscopic and nanoscopic techniques to characterize and understand their chemistry. X-ray photoelectron spectroscopy (XPS) has proved to be a useful analytical tool for nanoscale surface characterization of materials including carbon nanotubes. Recent nanotechnology research at NASA Johnson Space Center (NASA-JSC) helped to establish a characterization protocol for quality assessment for single wall carbon nanotubes (SWCNTs). Here, a review of some of the major factors of the XPS technique that can influence the quality of analytical data, suggestions for methods to maximize the quality of data obtained by XPS, and the development of a protocol for XPS characterization as a complementary technique for analyzing the purity and surface characteristics of SWCNTs is presented. The XPS protocol is then applied to a number of experiments including impurity analysis and the study of chemical modifications for SWCNTs.

Characterization techniques for graphene-based materials in catalysis

Directory of Open Access Journals (Sweden)

Maocong Hu

2017-06-01

Full Text Available Graphene-based materials have been studied in a wide range of applications including catalysis due to the outstanding electronic, thermal, and mechanical properties. The unprecedented features of graphene-based catalysts, which are believed to be responsible for their superior performance, have been characterized by many techniques. In this article, we comprehensively summarized the characterization methods covering bulk and surface structure analysis, chemisorption ability determination, and reaction mechanism investigation. We reviewed the advantages/disadvantages of different techniques including Raman spectroscopy, X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FTIR and Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS, X-Ray diffraction (XRD, X-ray absorption near edge structure (XANES and X-ray absorption fine structure (XAFS, atomic force microscopy (AFM, scanning electron microscopy (SEM, transmission electron microscopy (TEM, high-resolution transmission electron microscopy (HRTEM, ultraviolet-visible spectroscopy (UV-vis, X-ray fluorescence (XRF, inductively coupled plasma mass spectrometry (ICP, thermogravimetric analysis (TGA, Brunauer–Emmett–Teller (BET, and scanning tunneling microscopy (STM. The application of temperature-programmed reduction (TPR, CO chemisorption, and NH3/CO2-temperature-programmed desorption (TPD was also briefly introduced. Finally, we discussed the challenges and provided possible suggestions on choosing characterization techniques. This review provides key information to catalysis community to adopt suitable characterization techniques for their research.

DNP-enhanced solid-state NMR spectroscopy of active pharmaceutical ingredients.

Science.gov (United States)

Zhao, Li; Pinon, Arthur C; Emsley, Lyndon; Rossini, Aaron J

2017-11-28

Solid-state NMR spectroscopy has become a valuable tool for the characterization of both pure and formulated active pharmaceutical ingredients (APIs). However, NMR generally suffers from poor sensitivity that often restricts NMR experiments to nuclei with favorable properties, concentrated samples, and acquisition of one-dimensional (1D) NMR spectra. Here, we review how dynamic nuclear polarization (DNP) can be applied to routinely enhance the sensitivity of solid-state NMR experiments by one to two orders of magnitude for both pure and formulated APIs. Sample preparation protocols for relayed DNP experiments and experiments on directly doped APIs are detailed. Numerical spin diffusion models illustrate the dependence of relayed DNP enhancements on the relaxation properties and particle size of the solids and can be used for particle size determination when the other factors are known. We then describe the advanced solid-state NMR experiments that have been enabled by DNP and how they provide unique insight into the molecular and macroscopic structure of APIs. For example, with large sensitivity gains provided by DNP, natural isotopic abundance, 13 C- 13 C double-quantum single-quantum homonuclear correlation NMR spectra of pure APIs can be routinely acquired. DNP also enables solid-state NMR experiments with unreceptive quadrupolar nuclei such as 2 H, 14 N, and 35 Cl that are commonly found in APIs. Applications of DNP-enhanced solid-state NMR spectroscopy for the molecular level characterization of low API load formulations such as commercial tablets and amorphous solid dispersions are described. Future perspectives for DNP-enhanced solid-state NMR experiments on APIs are briefly discussed. Copyright © 2017 John Wiley & Sons, Ltd.

Raman Spectroscopy of Microbial Pigments

Science.gov (United States)

Edwards, Howell G. M.; Oren, Aharon

2014-01-01

Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

Effect of dissolved oxygen on two bacterial pathogens examined using ATR-FTIR spectroscopy, microelectrophoresis, and potentiometric titration.

Science.gov (United States)

Castro, Felipe D; Sedman, Jacqueline; Ismail, Ashraf A; Asadishad, Bahareh; Tufenkji, Nathalie

2010-06-01

The effects of dissolved oxygen tension during bacterial growth and acclimation on the cell surface properties and biochemical composition of the bacterial pathogens Escherichia coli O157:H7 and Yersinia enterocolitica are characterized. Three experimental techniques are used in an effort to understand the influence of bacterial growth and acclimation conditions on cell surface charge and the composition of the bacterial cell: (i) electrophoretic mobility measurements; (ii) potentiometric titration; and (iii) ATR-FTIR spectroscopy. Potentiometric titration data analyzed using chemical speciation software are related to measured electrophoretic mobilities at the pH of interest. Titration of bacterial cells is used to identify the major proton-active functional groups and the overall concentration of these cell surface ligands at the cell membrane. Analysis of titration data shows notable differences between strains and conditions, confirming the appropriateness of this tool for an overall charge characterization. ATR-FTIR spectroscopy of whole cells is used to further characterize the bacterial biochemical composition and macromolecular structures that might be involved in the development of the net surficial charge of the organisms examined. The evaluation of the integrated intensities of HPO(2)(-) and carbohydrate absorption bands in the IR spectra reveals clear differences between growth protocols. Taken together, the three techniques seem to indicate that the dissolved oxygen tension during cell growth or acclimation can noticeably influence the expression of cell surface molecules and the measurable cell surface charge, though in a strain-dependent fashion.

Electrochemical Characterization of a PEMEC Using Impedance Spectroscopy

DEFF Research Database (Denmark)

Elsøe, Katrine; Grahl-Madsen, L.; Hjelm, Johan

2017-01-01

In this study, electrochemical impedance spectroscopy (EIS) is applied in combination with cyclic voltammetry (CV) and current density – cell voltage curves (iV-curves) to investigate the processes contributing to the total impedance of a polymer electrolyte membrane electrolysis cell (PEMEC). i......V-curves were linear above 0.35 A cm−2 implying ohmic processes to be performance limiting, however the impedance spectra showed three arcs indicating three electrochemical reactions at these conditions not to be purely ohmic, but also to have capacitive properties. A hypothesis that the composite Ir...

Photoelectron spectroscopy

International Nuclear Information System (INIS)

Bosch, A.

1982-01-01

In this work examples of the various aspects of photoelectron spectroscopy are given. The investigation was started with the development of an angle-resolved spectrometer so that the first chapters deal with angle-resolved ultra-violet photoelectron spectroscopy. To indicate the possibilities and pitfalls of the technique, in chapter II the theory is briefly reviewed. In chapter III the instrument is described. The system is based on the cylindrical mirror deflection analyzer, which is modified and improved for angle-resolved photoelectron spectroscopy. In combination with a position sensitive detector, a spectrometer is developed with which simultaneously several angle-resolved spectra can be recorded. In chapter IV, the results are reported of angle-integrated UPS experiments on dilute alloys. Using the improved energy resolution of the instrument the author was able to study the impurity states more accurately and shows that the photoemission technique has become an important tool in the study of impurities and the interactions involved. XPS and Auger results obtained from dilute alloys are presented in chapter V. It is shown that these systems are especially suited for the study of correlation effects and can provide interesting problems related to the satellite structure and the interaction of the impurity with the host. In chapter VI, the valence bands of ternary alloys are studied with UPS and compared to recent band structure calculation. The core level shifts are analyzed in a simple, thermodynamic scheme. (Auth.)

Characterization of insoluble organic matter in primitive meteorites by microRaman spectroscopy

Science.gov (United States)

Busemann, Henner; Alexander, M. O'd.; Nittler, Larry R.

2007-08-01

We have analyzed the chemically and isotopically well-characterized insoluble organic matter (IOM) extracted from 51 unequilibrated chondrites (8 CR, 9 CM, 1 CI, 3 ungrouped C, 9 CO, 9 CV, 10 ordinary, 1 CB and 1 E chondrites) using confocal imaging Raman spectroscopy. The average Raman properties of the IOM, as parameterized by the peak characteristics of the so-called D and G bands, which originate from aromatic C rings, show systematic trends that are correlated with meteorite (sub-) classification and IOM chemical compositions. Processes that affect the Raman and chemical properties of the IOM, such as thermal metamorphism experienced on the parent bodies, terrestrial weathering and amorphization due to irradiation in space, have been identified. We established separate sequences of metamorphism for ordinary, CO, oxidized, and reduced CV chondrites. Several spectra from the most primitive chondrites reveal the presence of organic matter that has been amorphized. This amorphization, usually the result of sputtering processes or UV or particle irradiation, could have occurred during the formation of the organic material in interstellar or protoplanetary ices or, less likely, on the surface of the parent bodies or during the transport of the meteorites to Earth. D band widths and peak metamorphic temperatures are strongly correlated, allowing for a straightforward estimation of these temperatures.

Electrochemical and wear behavior of niobium-vanadium carbide coatings produced on AISI H13 tool steel through thermo-reactive deposition/diffusion

International Nuclear Information System (INIS)

Castillejo Nieto, Fabio Enrique; Olaya Flores, Jhon Jairo; Alfonso Orjuela, Jose Edgar

2016-01-01

We deposited of niobium-vanadium carbide coatings on tool steel AISI H13 using the thermo-reactive substrates deposition/diffusion (TRD) technique. The carbides were obtained using salt baths composed of molten borax, ferroniobium, vanadium and aluminum, by heating this mixture at 1020°C for 4 hours. The coatings were characterized morphologically via electron microscopy scanning (SEM), the chemical surface composition was determined through X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX); the crystal structure was analyzed using x-ray diffraction (XRD), the mechanical properties of the coatings were evaluated using nano-indentation, The tribological properties of the coatings obtained were determined using a Pin-on-disk tribometer and the electrochemical behavior was studied through potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the hardness of the coated steel increased four times with respect to uncoated steel, and the electrochemical test established that the corrosion current is lower by one order of magnitude for coated steel

Pseudo-HE images derived from CARS/TPEF/SHG multimodal imaging in combination with Raman-spectroscopy as a pathological screening tool

International Nuclear Information System (INIS)

Bocklitz, Thomas W.; Salah, Firas Subhi; Vogler, Nadine; Heuke, Sandro; Chernavskaia, Olga; Schmidt, Carsten; Waldner, Maximilian J.; Greten, Florian R.; Bräuer, Rolf; Schmitt, Michael; Stallmach, Andreas; Petersen, Iver; Popp, Jürgen

2016-01-01

Due to the steadily increasing number of cancer patients worldwide the early diagnosis and treatment of cancer is a major field of research. The diagnosis of cancer is mostly performed by an experienced pathologist via the visual inspection of histo-pathological stained tissue sections. To save valuable time, low quality cryosections are frequently analyzed with diagnostic accuracies that are below those of high quality embedded tissue sections. Thus, alternative means have to be found that enable for fast and accurate diagnosis as the basis of following clinical decision making. In this contribution we will show that the combination of the three label-free non-linear imaging modalities CARS (coherent anti-Stokes Raman-scattering), TPEF (two-photon excited autofluorescence) and SHG (second harmonic generation) yields information that can be translated into computational hematoxylin and eosin (HE) images by multivariate statistics. Thereby, a computational HE stain is generated resulting in pseudo-HE overview images that allow for identification of suspicious regions. The latter are analyzed further by Raman-spectroscopy retrieving the tissue’s molecular fingerprint. The results suggest that the combination of non-linear multimodal imaging and Raman-spectroscopy possesses the potential as a precise and fast tool in routine histopathology. As the key advantage, both optical methods are non-invasive enabling for further pathological investigations of the same tissue section, e.g. a direct comparison with the current pathological gold-standard

Balloon and Button Spectroscopy: A Hands-On Approach to Light and Matter

Science.gov (United States)

Ribaudo, Joseph

2016-01-01

Without question, one of the most useful tools an astronomer or physicist can employ to study the universe is spectroscopy. However, for students in introductory physics or astronomy classes, spectroscopy is a relatively abstract concept that combines new physics topics such as thermal radiation, atomic physics, and the wave and particle nature of…

Single-molecule force spectroscopy: optical tweezers, magnetic tweezers and atomic force microscopy

Science.gov (United States)

Neuman, Keir C.; Nagy, Attila

2012-01-01

Single-molecule force spectroscopy has emerged as a powerful tool to investigate the forces and motions associated with biological molecules and enzymatic activity. The most common force spectroscopy techniques are optical tweezers, magnetic tweezers and atomic force microscopy. These techniques are described and illustrated with examples highlighting current capabilities and limitations. PMID:18511917