bluuebunny/crossref_metadata_2025 huggingface dataset:
The Transnational Community as an Agent for Caribbean Development: Aid from New York City and Toronto to Carriacou, Grenada
Authors: Mills Beth H
Published: October 2005

Small island economies of the Caribbean have traditionally relied on remittances from family members working abroad to sustain them in their limited circumstances. The responsibility to provide for those back home has evolved as the communities of Afro-Caribbean people in North America have prospered. For some islands, like Grenada and its dependencies of Carriacou and Petite Martinique, the present transnational network has become a complex and sophisticated vehicle for initiating and completing development projects in the Caribbean. Community social organization abroad, as well as access to the Internet as an organizing tool, allow transnational connections to flourish and provide much needed aid to the home community. Although these islands have a long history of migration and remittances, the transnational network fosters an organized and effective way of providing development aid at a larger, community-wide scale. This article uses examples, including interviews, from New York City and Toronto to give voice to these connections and projects.
Caribbean Peasantry Revisited: Barbadian Farmers over Four Decades
Authors: Momsen Janet Henshall
Published: October 2005

Peasantries are often seen as both unchanging and disappearing. This paper traces the transformation of the Barbadian peasant farm over four decades based on three repeat surveys undertaken in 1963, 1987 and 2003. It suggests that although the peasant farm acreage has fallen significantly over the period, the remaining farms have been transformed both in terms of crops grown and the markets served. Over a period during which Barbados has changed from an archetypal colonial sugar island to one whose economy is now dominated by tourism, small scale agriculture both reflects these changes and has adapted to them.
Environmental Planning in Barbados: A Confident State, Isolated Environmental Movements, and Anxious Development Consultants
Authors: Pugh Jonathan
Published: October 2005

This paper explores the 'confidence' that different groups have during environmental planning in Barbados. It shows how anxious donor agencies and Western consultants have been accused of projecting their vision of development onto the country. I examine how isolated environmental movements act unaccountably on behalf of a disengaged population. As a result, with the legacy of independence still in people's memories, the State of Barbados speaks with a certain amount of legitimacy when undertaking environmental planning.
The Distribution of Casuarinas on San Salvador Island, The Bahamas
Authors: Rodgers John Clair
Published: October 2005

This study investigates the distribution of Casuarinas, a noxious invasive plant species, on San Salvador Island, The Bahamas. The location of Casuarina individuals, clumps (4-20 individuals), and stands (>20 individuals) were mapped using a global positioning system. These locations were then compared to human settlement patterns. Casuarina distribution is strongly associated with human habitation. They had the highest abundance and the largest number of stands in the most populated areas, such as the western and northern regions of the island. They had the lowest abundance in the least populated areas, such as the eastern and southern regions of the island. The presence of individual Casuarinas and clumps of Casuarinas along roadsides in unpopulated regions suggests that they may be spreading without the aid of people into areas that are undeveloped. This migration is possibly occurring along roadways where favorable conditions (more light and less competition) may be providing footholds.
MADSTRESS: A Linear Approach for Evaluating Scattering and Absorption Coefficients of Samples Measured Using Time-Resolved Spectroscopy in Reflection
Authors: Chauchard F. , Roger J. M. , Bellon-Maurel V. , Abrahamsson C. , Andersson-Engels S. , Svanberg S.
Published: October 2005

Time-resolved spectroscopy is a powerful technique permitting the separation of the scattering properties from the chemical absorption properties of a sample. The reduced scattering coefficient and the absorption coefficient are usually obtained by fitting diffusion or Monte Carlo models to the measured data using numerical optimization techniques. However, these methods do not take the spectral dimension of the data into account during the evaluation procedure, but evaluate each wavelength separately. A procedure involving multivariate methods may seem more appealing for people used to handling conventional near-infrared data. In this study we present a new method for processing TRS spectra in order to compute the absorption and reduced scattering coefficients. This approach, MADSTRESS, is based on linear regression and a two-dimensional (2D) interpolation procedure. The method has allowed us to calculate absorption and scattering coefficients of apples and fructose powder. The accuracy of the method was good enough to provide the identification of fructose absorption peaks in apple absorption spectra and the construction of a calibration model predicting the sugar content of apples.
A New Fourier Transform Infrared Method for the Determination of Moisture in Edible Oils
Authors: Al-Alawi Ahmed , Van De Voort Frederick R. , Sedman Jacqueline
Published: October 2005

A rapid, practical, and accurate Fourier transform infrared (FT-IR) method for the determination of moisture content in edible oils has been developed based on the extraction of water from oil samples into dry acetonitrile. A calibration curve covering a moisture content range of 0–2000 ppm was developed by recording the mid-infrared (MIR) spectra of moisture standards, prepared by gravimetric addition of water to acetonitrile that had been dried over molecular sieves, in a 500 μm ZnSe transmission flow cell and ratioing these spectra against that of the dry acetonitrile. Water was measured in the resulting differential spectra using either the OH stretching (3629 cm−1) or bending (1631 cm−1) bands to produce linear standard curves having standard deviations (SDs) of approximately ±20 ppm. For moisture analysis in oils, the oil sample was mixed with dry acetonitrile in a 1:1 w/v ratio, and after centrifugation to separate the phases, the spectrum of the upper acetonitrile layer was collected and ratioed against the spectrum of the dry acetonitrile used for extraction. The method was validated by standard addition experiments with samples of various oil types, as well as with oil samples deliberately contaminated with alcohols, hydroperoxides, and free fatty acids to investigate possible interferences from minor constituents that may be present in oils and are potentially extractable into acetonitrile. The results of these experiments confirmed that the moisture content of edible oils can be assessed with high accuracy (on the order of ±10 ppm) by this method, thus providing an alternative to the conventional, but problematic, Karl Fischer method and facilitating the routine analysis of edible oils for moisture content.
Characterization of Historic Silk by Polarized Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy for Informed Conservation
Authors: Garside Paul , Lahlil Sophia , Wyeth Paul
Published: October 2005

When assessing historic textiles and considering appropriate conservation, display, and storage strategies, characterizing the physical condition of the textiles is essential. Our work has concentrated on developing nondestructive or micro-destructive methodologies that will permit this. Previously, we have demonstrated a correlation between the physical deterioration of unweighted and “pink” tin (IV) chloride weighted silk and certain measurable spectroscopic and chromatographic signatures, derived from polarized Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy (Pol-ATR) and high-performance liquid chromatography (HPLC) microsampling analyses. The application of the Pol-ATR technique to aged silk characterization has now been extended to include a more comprehensive range of weighting methods and aging regimes. This was intended to replicate the full spectrum of states of deterioration observed in silk textiles, from pristine to heavily degraded. Breaking strength was employed as a measure of the physical integrity of the fibers, and, as expected, decreased with aging. An orientational crystallinity parameter, reflecting the microstructural ordering of the fibroin polymer within the fibers, was derived from the Pol-ATR spectra. A good correlation was observed between the breaking strength of the variety of fibers and this parameter. This suggests that the physical state of historic silk fabrics might be adequately characterized for conservation purposes by such indirect micromethodology.
Vibrational Behavior of the −NO2 Group in Energetic Compounds
Authors: Beal Royce W. , Brill Thomas B.
Published: October 2005

The vibrational modes of the –NO2 group in more than fifty energetic compounds containing the C-nitro and N-nitro functionalities were observed and then calculated in optimized structures using density functional theory (B3LYP/6–31+G*). The trends in the symmetric and asymmetric stretches and scissor and out-of-plane deformations were explained by these calculations. A previously unreported correlation was found between the nitro group internal bonding angle and its asymmetric stretching frequency. The concept of meta and ortho/para directing groups was applicable to the trends in coupled motions in the nitroaromatic compounds. Both the scissor motion of C–NO2 groups and the out-of-plane deformation of N–NO2 groups were found to be virtually insensitive to the remainder of the molecule. These findings may be useful in analytical methods of explosive detection based on their infrared (IR) spectra.
Molecular Orientation of Poly(Ethylene Terephthalate) and Poly(Butylene Terephthalate) Probed by Polarized Raman Spectra: A Parallel Study
Authors: Soto A. , Iconomopoulou S. M. , Manikas A. C. , Voyiatzis G. A.
Published: October 2005

Poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) samples uniaxially drawn above Tg and beyond the yield point exhibit significant differences in their molecular orientation behavior as probed by polarized Raman spectra. The quasi-amorphous PET samples, drawn close to the Tg, manifest considerable molecular orientation development; however, when drawn above Tg + 30 °C, they exhibit significant molecular orientation relaxation. The semi-crystalline PBT samples maintain prominent molecular orientation even when drawn 110 °C above Tg. The drawing process, in PET samples, when resulting in molecular orientation, is accompanied by a gauche–trans transformation of the glycol linkage and a concurrent initiation of crystallinity development. In PBT specimens, it gives rise to a coexistence of α- and β-type crystalline phases. Phase a is predominant at high draw temperatures, i.e., Tg + 110 °C, while phase β dominates at low draw temperatures, i.e., Tg + 10 °C. PBT samples, with β-phase predominance, left at relevant draw temperatures without stress, exhibit a β–α phase change though no molecular orientation relaxation occurs. A note is made of the fact that complete molecular orientation analysis of PBT segments utilizing the depol method gives more reliable results than the simplified analysis assuming a cylindrical tensor for the 1614 cm−1 symmetric stretch of the para-disubstituted benzene ring of PBT. In this context, segments of PBT specimens rich in α-phase exhibit higher molecular orientation than those with β-phase predominance.
Comparison of Psychro-Active Arctic Marine Bacteria and Common Mesophillic Bacteria Using Surface-Enhanced Raman Spectroscopy
Authors: Laucks Mary L. , Sengupta Atanu , Junge Karen , Davis E. James , Swanson Brian D.
Published: October 2005

Psychro-active bacteria, important constituents of polar ecosystems, have a unique ability to remain active at temperatures below 0 °C, yet it is not known to what extent the composition of their outer cell surfaces aids in their low-temperature viability. In this study, aqueous suspensions of five strains of Arctic psychro-active marine bacteria (PAMB) (mostly sea-ice isolates), were characterized by surface-enhanced Raman spectroscopy (SERS) and compared with SERS spectra from E. coli and P. aerigunosa. We find the SERS spectra of the five psychro-active bacterial strains are similar within experimental reproducibility. However, these spectra are significantly different from the spectra of P. aeruginosa and E. coli. We find that the relative intensities of many of the common peaks show the largest differences reported so far for bacterial samples. An indication of a peak was found in the PAMB spectra that has been identified as characteristic of unsaturated fatty acids and suggests that the outer membranes of the PAMB may contain unsaturated fatty acids. We find that using suspensions of silver colloid particles greatly intensifies the Raman peaks and quenches the fluorescence from bacterial samples. This technique is useful for examination of specific biochemical differences among bacteria.
Molecular Ordering in Monolayers of an Alkyl-Substituted Perylene-Bisimide Dye by Attenuated Total Reflectance Ultraviolet—Visible Spectroscopy
Authors: Doherty Walter J. , Simmonds Adam G. , Mendes Sergio B. , Armstrong Neal R. , Saavedra S. Scott
Published: October 2005

Surface-relative orientational parameters were determined for monolayer films of N, N′-ditridecylperylenetetracarboxylic dianhydridediimide (C13-PTCDI) in terms of the relative electronic transition dipole strengths, providing a three-dimensional view of the absorption dipole distribution. In order to obtain a macroscopically ordered film, C13-PTCDI was deposited by (1) horizontal Langmuir–Blodgett (LB) transfer onto methyl- and phenyl-silanized glass, and (2) vapor deposition onto oriented films of poly(tetrafluoroethylene) (PTFE) on glass. Films of LB-deposited C13-PTCDI were found to be completely isotropic prior to annealing. After annealing, these films remained isotropic in the plane of the substrate while the out-of-plane anisotropy was significantly enhanced. In contrast, films of C13-PTCDI vapor deposited onto oriented poly(tetrafluoroethylene) (PTFE)-modified substrates yielded films with a high degree of both in- and out-of-plane anisotropy. Atomic force microscopy (AFM) images of both the LB- and vapor-deposited films show substantial differences in film morphology and long-range order. These results demonstrate that molecular orientation in C13-PTCDI films can be controlled by varying substrate surface chemistry and post-deposition processing.
Spectral Variable Selection for Partial Least Squares Calibration Applied to Authentication and Quantification of Extra Virgin Olive Oils Using Fourier Transform Raman Spectroscopy
Authors: Heise H. Michael , Damm Uwe , Lampen Peter , Davies Antony N. , McIntyre Peter S.
Published: October 2005

The limits of quantitative multivariate assays for the analysis of extra virgin olive oil samples from various Greek sites adulterated by sunflower oil have been evaluated based on their Fourier transform (FT) Raman spectra. Different strategies for wavelength selection were tested for calculating optimal partial least squares (PLS) models. Compared to the full spectrum methods previously applied, the optimum standard error of prediction (SEP) for the sunflower oil concentrations in spiked olive oil samples could be significantly reduced. One efficient approach (PMMS, pair-wise minima and maxima selection) used a special variable selection strategy based on a pair-wise consideration of significant respective minima and maxima of PLS regression vectors, calculated for broad spectral intervals and a low number of PLS factors. PMMS provided robust calibration models with a small number of variables. On the other hand, the Tabu search strategy recently published (search process guided by restrictions leading to Tabu list) achieved lower SEP values but at the cost of extensive computing time when searching for a global minimum and less robust calibration models. Robustness was tested by using packages of ten and twenty randomly selected samples within cross-validation for calculating independent prediction values. The best SEP values for a one year's harvest with a total number of 66 Cretian samples were obtained by such spectral variable optimized PLS calibration models using leave-20-out cross-validation (values between 0.5 and 0.7% by weight). For the more complex population of olive oil samples from all over Greece (total number of 92 samples), results were between 0.7 and 0.9% by weight with a cross-validation sample package size of 20. Notably, the calibration method with Tabu variable selection has been shown to be a valid chemometric approach by which a single model can be applied with a low SEP of 1.4% for olive oil samples across three different harvest years.
Measurement of Polystyrene Nanospheres Using Excimer Laser Fragmentation Fluorescence Spectroscopy
Authors: Choi Jong Hyun , Koshland Catherine P. , Sawyer Robert F. , Lucas Donald
Published: October 2005

Monodisperse polystyrene nanospheres with a mean diameter of 102 nm are photofragmented with 193 nm light in N2 at laser fluences from 1 to 20 J/cm2. Carbon atom fluorescence at 248 nm from the disintegration of the particles is used as a signature of the polystyrene. The normalized fluorescence signals are self-similar with an exponential decay lifetime of ∼10 ns. At fluences above 17 J/cm2, optical breakdown occurs and a strong continuum emission is generated that lasts significantly longer. A non-dimensional parameter, the photon-to-atom ratio (PAR), is used to interpret the laser-particle interaction energetics. Carbon fluorescence from polystyrene particles is compared with that from soot, and a similarity between the two particles is observed when normalized with PAR. Carbon emission from bulk polystyrene was also measured. Similar emission signals were observed, but the breakdown threshold of the surface is significantly lower at 0.2 J/cm2.
Fluorescence Quenching of the Europium Tetracycline Hydrogen Peroxide Complex by Copper (II) and other Metal Ions
Authors: Cano-Raya Clara , Ramos María. D. Fernández , Vallvey Luís. F. Capitán , Wolfbeis Otto S. , Schäferling Michael
Published: October 2005

The europium–tetracycline complex [Eu(Tc)] is known to show only weak fluorescence with an emission maximum at 615 nm. On addition of hydrogen peroxide (HP), the strongly fluorescent [Eu(Tc)(HP)] complex is formed, which displays a 15-fold stronger luminescence intensity. This study describes the decrease in luminescence intensity of the [Eu(Tc)(HP)] complex in aqueous solution in the presence of Cu2+, Fe3+, Ag+, Al3+, Zn2+, Co2+, Ni2+, Mn2+, Ca2+, and Mg2+. Static and dynamic quenching can be induced by Cu2+, and these processes were quantified by means of their quenching constants. Stern–Volmer plots were also derived from lifetime imaging measurements accomplished by the rapid lifetime determination (RLD) technique based on microwell plate assays, and also by the time-correlated single photon counting (TCSPC) technique. According to those data, a time-resolved fluorescent method for copper determination can be proposed that is based on dynamic quenching of the [Eu(Tc)(HP)] complex by Cu2+ ions. The response to copper concentrations is linear up to 1.6 μmol L−1, providing a detection limit of 0.2 μmol L−1.
Monitoring of Emulsion Polymerization Reactors by Raman Spectroscopy: Calibration Model Maintenance
Authors: Elizalde Oihana , Asua José M. , Leiza Jose R.
Published: October 2005

Fourier transform (FT)-Raman combined with partial least squares regression (PLS-R) calibration models allows the accurate monitoring of solids content, copolymer composition, and free amounts of monomers in starved semi-batch emulsion copolymerizations. The calibration models remain valid as long as the spectrometer and the measuring conditions are unchanged. Unfortunately, maintenance and/or repairing of the spectrometer result in changes in the relative intensities of the peaks of the Raman spectrum, reducing the performance of the calibration models. Therefore, a strategy for the up-date of the PLS-R calibration models is needed. Strategies for calibration model maintenance were assessed, and we found that the best strategy was to build a new model composed of the old PLS-R model plus a PLS-R model able to account for the model mismatch of the old model.
Novel Attenuated Total Reflection Fourier Transform Infrared Microscopy Using a Gem Quality Diamond as an Internal Reflection Element
Authors: Ekgasit Sanong , Thongnopkun Pimthong
Published: October 2005

A novel technique for attenuated total reflection Fourier transform infrared (ATR FT-IR) spectral acquisition by an infrared microscope with a gem-quality faceted diamond as an internal reflection element (IRE) is introduced. Unlike conventional IREs, the novel diamond IRE has a sharp tip configuration instead of a flat tip configuration. Light at normal incidence was coupled into the diamond while the transflected radiation from the diamond was collected through the table facet by the built-in 15× Cassegrainian objective. The number of reflections in the novel diamond IRE equals two. The evanescent field generated under total internal reflection at the pavilion facet was exploited for ATR spectral acquisition of materials attached to the IRE. The observed ATR spectra were compared to those obtained via a traditional zinc selenide IRE.
New Strategy for Ready Application of Surface-Enhanced Resonance Raman Scattering/Surface-Enhanced Raman Scattering to Chemical Analysis of Organic Films on Dielectric Substrates
Authors: Kim Kwan , Kim Nam Hoon , Park Hyoung Kun , Ha Young Soo , Han Hyouk Soo
Published: October 2005

Dropping of appropriately concentrated AgNO3 and NaBH4 solutions, as well as laser-ablated Ag sols, onto organic molecules results in the formation of aggregated Ag nanoparticles that can induce surface-enhanced Raman scattering (SERS) for the molecules. The addition of flocculating agents such as alkali halides can further increase the Raman signals. We demonstrate in this work that Raman spectra can be obtained even for 0.01 monolayers of R6G on Si simply by spreading silver nanoparticles and/or fabricating Ag nanoparticles and nanoaggregates at the gaps and vacant sites of R6G molecules. The application prospect of the present methodology is extremely high, not only because of its simplicity but also because of the fact that the observation of vibrational spectra is one of the most incisive methods for understanding the chemical and physical phenomena on a variety of surfaces.
Passive Standoff Detection of SF6 at a Distance of 5.7 km by Differential Fourier Transform Infrared Radiometry
Authors: Lavoie Hugo , Puckrin Eldon , Thériault Jean-Marc , Bouffard François
Published: October 2005

Recent results are presented on the passive detection, identification, and quantification of a vapor cloud of SF6 measured at a horizontal standoff distance of 5.7 km using a dual-beam interferometer optimized for background signal suppression. The measurements were performed at Defense Research and Development Canada (DRDC)–Valcartier during a number of recent open-air experiments. The measurement approach is based on the differential passive standoff detection method that has been developed by DRDC Valcartier during the past few years. This work represents the first such measurement reported in the open literature for a standoff distance as large as 5.7 km. These results clearly demonstrate the capability of the differential radiometry approach to the detection, identification, and quantification of chemical vapor clouds located at long distances from the sensor.
Monitoring of High Solids Content Starved-Semi-Batch Emulsion Copolymerization Reactions by Fourier Transform Raman Spectroscopy
Authors: Elizalde Oihana , Asua José M. , Leiza Jose R.
Published: October 2005

A high solids content n-butyl acrylate/methyl methacrylate emulsion copolymerization process carried out under starved semi-batch conditions was for the first time monitored on-line by means of Fourier transform (FT)-Raman spectroscopy. Partial least squares regression was employed to build calibration models that allowed relating the spectra with solids content (overall conversion), free amounts of both n-butyl acrylate (n-BA) and methyl methacrylate (MMA), and cumulative copolymer composition. In spite of the heterogeneous nature of the polymerization, the similarities of the spectra for MMA, n-BA, and for the copolymer, and the low monomer concentrations in the reactor, the FT-Raman spectroscopy has been shown to be a suitable noninvasive sensor to accurately monitor the process. Therefore, it is well suited for on-line control of all-acrylic polymerization systems.
A High Speed Method of Continuous Background Correction in Atomic Absorption Spectrometry
Authors: Donnelly T. H. , Eccleston A. J. , Gully R. L.
Published: October 2005

Background correction in atomic absorption spectrometry using high speed electronic circuitry has been developed. Electrical responses are generated from two light sources: an atomic spectral lamp and a modified Beckman hydrogen arc lamp. Repetition rate of the pulses (2.6 msec) was limited by the increasing distortion of the pulse shape. Instantaneous relationships between the various electronic components was established using a synchronizing pulse generator.
A High Speed Method of Continuous Background Correction in Atomic Absorption Spectrometry. III. Direct Determination of Trace Metals in Sea Water Using the Varian Techtron Carbon Rod Atomizer Model 63
Authors: Donnelly T. H. , Ferguson J. , Eccleston A. J.
Published: October 2005

A newly developed method of background correction for atomic absorption spectrometry combined with the Varian Techtron carbon rod atomizer, model 63, has been applied to the direct determination of Pb, Zn, Fe, Cu, Ni, Co, and Cd in sea water. The background-corrected absorption measurements are reproducible and have a linear relationship to increasing additions of the metal over the ranges examined for the direct determination of metals in sea water. The values are comparable to those obtained by the accepted ammonium tetramethylenedithiocarbamate-methyl isobutyl ketone flame atomic absorption spectrometry method, within the limits of precision expected. However, except for Fe and Zn, the method is not sensitive enough to allow measurements at the lower concentration ranges of the metals in sea water. The direct method is a rapid technique for analyzing marine waters enriched in metals.
Resolution Enhancement of X-ray Fluorescence Spectra with a Computerized Multichannel Analyzer
Authors: Stewart James E.
Published: October 2005

The relationship between the shape of a real spectrum and the representation of the spectrum that is generated by a linear spectrometer may be described by a Fredholm integral equation. The Burger-van Cittert iterative method for solving the equation is applied to x-ray fluorescence spectra. The extent of enhancement that may be reached is limited by overcorrection in the wings of the recorded lines and the appearance of negative lobes. Reduction in line width of about 20% is a practical limit. There is an inherent increase in noise caused by the enhancement procedure, but this can be minimized by a subsequent spectral smoothing operation. The Burger-van Cittert method is especially suited to on-line treatment of data with a minicomputer or a computer-controlled multichannel analyzer.
Biochemical Applications of Infrared and Raman Spectroscopy
Authors: Parker Frank S.
Published: October 2005

Uses to which infrared and Raman spectroscopy have been put in biochemical work are reviewed. In the infrared field some of the applications discussed are hydrogen bonding, carbohydrates, lipids, proteins and polypeptides, hydrogen-deuterium exchange, nucleic acids, steroids, porphyrins, enzymology, and medical uses, among others. In the Raman field some of the applications discussed are polypeptides, proteins and enzymes, nucleic acids, carbohydrates, steroids, membranes, lipids, and calcified tissues. Some applications of resonance-Raman spectroscopy are discussed. They include such substances as carotenoids and plant pigments, enzymes, hemoglobin, cytochrome c, hemocyanin, visual pigments, and protein-ligand and antibody-hapten interactions. The kinds of information obtainable with each of the methods and the various classes of biochemical substances are given in some detail, and pertinent references are supplied.
Alkali Analysis Using Light Reflected from the Grating of an Optical Emission Spectrometer
Authors: Hodges R. J. , Belcher C. B.
Published: October 2005

A modification to a vacuum direct reading optical emission spectrometer is described. The light reflected from the grating is focussed onto the entrance slit of a secondary monochromator to extend the range of wavelengths available. Results for the analysis of sodium in mineral, rock, and ash samples by a fusion briquette method are given. The application to the analysis of other alkalis and to background correction is discussed.
New Slitless Optical Fiber Laser-Raman Spectrometer
Authors: Walrafen G. E.
Published: October 2005

A new slitless optical fiber laser-Raman spectrometer has been developed in which long, thin, low loss optical fibers, either liquid filled or solid core, act simultaneously as the sample and entrance aperature. The fiber end is placed at the focus of the collimator lens, and the resultant parallel radiation is dispersed by three large triangular Steinheil prisms in series. The dispersed radiation is then focussed by the camera lens to a series of points in the focal plane. The Raman points are detected photoelectrically by scanning with either an exit pinhole or slit, and a photomultiplier whose photocathode surface can be as small as the fiber end. Because of the long fiber lengths employed and of the high transmission efficiency of the spectrometer, very large Raman signals result. For example, the extremely weak Raman intensity maximum from fused silica at Δ v̄bar; ≈ 2165 cm−1 is readily detected visually in the focal plane using a fiber length of 85 m and a few hundred milliwatts of 476.5 nm excitation. The new spectrometer will be of considerable use in Raman studies of pure and doped glasses in fiber form, and of a wide range of liquids and mixtures where small sample amounts are involved. It may also be possible eventually to extend this slitless method to studies of water, aqueous solutions, and gases by employing straight dielectric waveguide techniques.
Lattice Phonon Spectra of Aluminum Oxide Anodic Films
Authors: Chatelet J. , Claassen H. H. , Gruen D. M. , Sheft I. , Wright R. B.
Published: October 2005

Techniques have been developed for obtaining reproducible lattice phonon spectra of barrier aluminum oxide anodic films. Changes in the lattice phonon spectrum as a result of 15-keV proton bombardment are interpreted in terms of the formation of Al-OH bonds. Polarization spectra of stripped and unstripped aluminum oxide films confirm the findings of Vedder and Vermilyea, particularly with respect to the origin of the 960 cm−1 band. The close similarity in the observed and calculated band shapes (using the theory of Berreman) leave little doubt that the 960 cm−1 absorption is due to a longitudinal optic mode of the aluminum oxide lattice.
X-ray Spectrometric Analysis of Plutonium-Zirconium Alloys
Authors: Walden J. C. , Wallace P. L. , Magana J. W.
Published: October 2005

An x-ray spectrometric method for analyzing binary plutonium-zirconium alloys containing 1 to 25 wt% Zr has been developed. The alloys are analyzed as solutions in 8 M nitric acid. Yttrium is added as an internal standard. The techniques involved in handling and containing the radioactive solutions in conventional liquid cells are described in detail. No modifications to the x-ray spectrometer are required. Adaptations of this method have been used for the analysis of binary plutonium-gallium and plutonium-uranium alloys.
The Spectral Energy Value System
Authors: Anderson Philip C.
Published: October 2005

This paper presents the spectral energy value system as a conceptualization of the nature of intramolecular energy structure. Using data from emission spectroscopy, the author has constructed structural representations of molecular “electromagnetic” energies. These spectral energy structures are corroborated by data from several independent branches of physical chemistry. Nonzero values for average emission line energies of diatomic molecules of elements in their standard states are proposed. Then it is shown that a total molecular energy calculated from thermodynamic data can be accounted for simply as an arithmetic summation of emission line energies of constituent atoms. Allocation of spectral energy and nuclidal mass to chemical bonds is shown to conform to a simple equivalence relation. Spectral energy structures for over 100 simple molecules have been constructed. The spectral energy structure of methane is discussed in detail. The concept of spectral energy density is introduced, and its general implications for physical chemistry are indicated. A particular example of the utility of this concept is a possible solution to the metabolic riddle of amino acid essentiality.
Automated Direct Current Arc Time Studies Using a Computer-Coupled Photodiode Array Spectrometer
Authors: Horlick Gary , Codding Edward G. , Leung S. T.
Published: October 2005

A hardware and software system has been developed which is capable of automatically acquiring and analyzing intensity-time data from a dc arc source. This system is based on a computer-coupled photodiode array spectrometer with which 260 Å of continuous spectral information can be simultaneously measured and stored directly in a small computer. With the present system up to seven time sequential spectra, each representing the integral of the spectral intensity over times ranging from 1 to 10 sec, can be automatically obtained during a dc arc burn. The time interval spectra can then be analyzed under computer control and the intensity-time curves for any desired lines can be plotted on a computer terminal within about 2 min after termination of the are burn. The application of the system to some simple dc arc time studies is discussed and illustrated.
The Determination of Parts per Million Levels of Thorium in Optical Components by X-ray Fluorescence
Authors: Keenan Joseph A.
Published: October 2005

A nondestructive technique for the determination of thorium in optical glass has been devised using tube-excited x-ray fluorescence with an energy-dispersive detector. Capability for full calibration and sample analysis has been incorporated into a computer-coupled system. Bulk thorium concentrations as low as 87 ppm have been detected with a coefficient of variation of 27.2% at 95% confidence using NBS-certified standards. At 466 ppm the coefficient of variation was 5.6% at the 95% confidence level. Qualitative determination of thorium in optical coatings has been demonstrated also.
Atomic Absorption Spectrometry with Absorption Tube Technique
Authors: Uchida Tetsuo , Iida Chuzo
Published: October 2005

In atomic absorption spectrometry with the long absorption tube using a hydrogen-air flame and ring burner, the various effects such as the external heating of the tube, rate of exhaust of the burnt gas, and preheating of the aspirating air on the sensitivity, detection limit, and memory effect for 24 elements were studied. The optimal flame conditions were appreciably affected by the rate of exhaust of burnt gas. Preheating of the aspirating air resulted in 3 to 10% enhancement in sensitivity for silver, zinc, and antimony. By external heating of the tube, more than 40% enhancement in sensitivity was obtained for manganese, copper, gallium, silver, antimony, and bismuth. The detection limits were also lowered considerably for gallium, tin, antimony, mercury, and bismuth.
The Determination of Barium and Antimony in Gunshot Residue by Flameless Atomic Absorption Spectroscopy Using a Tantalum Strip Atomizer
Authors: Goleb J. A. , Midkiff C. R.
Published: October 2005

A flameless atomic absorption technique, employing a tantalum strip atomizer, has been developed to determine barium and antimony in gunshot residue. Cotton swabs, wetted with 5% HNO3, are used to collect residue. Barium and antimony are released from the swabs by acid leaching or plasma ashing. Both techniques give good recoveries; the ashing technique is preferred for blood-stained swabs. The sensitivity for barium is 0.1 ng/10 µl and antimony 0.2 ng/10 µl. At nanogram levels the standard relative deviation for barium is 8.3% and for antimony 8.5%.
Biochemical Applications of Flame Emission and Atomic Absorption Spectroscopy
Authors: Berman Eleanor
Published: October 2005

Certain aspects of the current status of biochemical applications of flame emission and atomic absorption spectroscopy are discussed. Various techniques described for determination of 21 elements are compared. Interferences due to the composition of the biological matrix are emphasized.
Atomic Absorption Interferences Using a Tantalum Boat Atomizing System
Authors: Schrenk W. G. , Everson Richard T.
Published: October 2005

A tantalum boat was used to study interference effects for the elements zinc, copper, manganese, iron, and sodium. The maximum absorption signal depended on the temperature of the boat and on how long a particular temperature was applied. The parameters were different for each element. Calibration curves for zinc, copper, and manganese differed for the different anions with which they were associated. For anions studied (chloride, nitrate, and sulfate), chloride in each case produced the largest absorption signal for the metal atom. Absorption responses of zinc, copper, and manganese were studied in the presence of a series of added ions: Na+, Ca2+, Fe2+, Mg2+, Cu2+, SO42−, and PO43−. The effects of all except Ca2+ and PO43− were negligible. Ca2+ and PO43− caused the largest signal depression, although SO42− also caused some. As the temperature of the tantalum boat was increased, the interference effect decreased but did not vanish. The absorption signal of Na+, studied in the presence of Li+, Rb+, and Cs+, was enhanced slightly in each case, but the effect was less than that observed for the same systems when aspirating a liquid sample into a flame cell.
Photometric Precision in Infrared Spectra Measured by Fourier Transform Spectroscopy
Authors: Griffiths Peter R.
Published: October 2005

Digitally recorded spectra containing lines of width less than or equal to the resolution at which the measurement has been made are observed to show some photometric In spectra measured by Fourier transform spectroscopy, this error may be substantially reduced if the interferogram is zero-filled. To prevent the generation of artifacts in the spectrum (of a similar origin to the sine x side-lobes formed when a non-zero-filled spectrum is computed with a box-car truncation function), the zero-filled interferogram must be suitably apodized.
Optical Spectra, Electrical Conductances, Densities, and Viscosities of Glass-Forming Melts
Authors: Islam N. , Islam M. R. , Ahmad S. , Waris B.
Published: October 2005

The charge-transfer bands of I− in thin film spectra of MCl2 (M = Mn, Co, and Ni)-rich mixtures of tetra- n-alkyl* (A* = butyl, pentyl, hexyl, and heptyl, respectively), and tributylpropyl-ammonium iodides have been found to resemble those of crystalline potassium-, rubidium-, and cesium-iodides.1 (The band separation corresponds to 0.87 to 0.97 eV as against 0.94 to 1.15 eV found in the spectra of crystalline KI, RbI, and CsI, and 0.94 eV for 52P3/2 ← 52P1/2 transitions in the case of iodine atom.) In addition to the usual d- d bands, the charge-transfer bands of CoX4− and NiX4− which are ordinarily obscured by the absorption of X− are also observed. The band assignments of NiX4− have been made in the light of the calculated electronic energy levels of tetrahalonickel (II) complexes using the Liehr-Ballhausen secular determinants for the d8 system in a cubic tetrahedral field based on the four ligand-field parameters (NiCl4−: λ = −275, B = 740.00, C/B = 3.97, Dq = 358; NiCl2Br2−: λ = −275, B = 713.75, C/B = 3.93, Dq = 346; and NiCl2 I2−: λ = −275, B = 637.75, C/B = 4.7, Dq = 346 cm−1). Similarly, the charge-transfer bands of Br− and Cl− are also obtained in thin film spectra of MCl2 (M = Mn, Co, and Ni) in tetrabutyl-, and trioctylpropyl-ammonium bromides, and tetrabutyl-ammonium chloride, respectively. The degree of dissociation of MX4− is negligible in pure (A4N+)2MX4− (where A stands for either the same or different alkyl groups) as apparent from the decrease in the electrical conductances with [MX2]. The species, (A4N+)2MX4−, appear to be held together with increased intermolecular forces at low temperatures as evident from the (increase in the Eη;, energy of activation of viscosity) kinematic viscosity measurements. The data on the energies of activation of conductances and viscosities as functions of composition and temperature suggest an increased molecular association (as their ratio Eη;/EΛ ≈ 1) in such systems. The conductances and viscosities have been analyzed in terms of different functional forms based on the free volume model. The Walden's product rule has been found applicable in these systems.
On Line Infrared Identification of Gas Chromatography Effluents
Authors: Katlafsky B. , Dietrich M. W.
Published: October 2005

On-line infrared spectra obtained with the Norcon RS-1 gas chromatographic identifier are of sufficient quality for qualitative identification of functional groups, chemical classes, or chemical entities. Identification limits for chemical entities vary between 20 and 200 µg, polar compounds having higher sensitivities. Functional group identifications can be made with correspondingly smaller samples. A 5-fold increase in sensitivity was demonstrated using signal-averaging techniques.
On the Importance of Spectral Interferences in Atomic Absorption Spectroscopy
Authors: Lovett R. J. , Welch D. L. , Parsons M. L.
Published: October 2005

Various types of spectral interferences in atomic absorption spectroscopy were investigated. Of particular concern were interferences in which atomic electronic processes are a problem. Source emission of multiplets and other radiation near the analysis line can cause nonlinear analytical curves and poor detection limits. Direct absorption spectral overlaps were found to be of importance in some analyses, particularly for transition elements. Comprehensive lists of observed and predicted spectral interferences are presented. It is concluded that spectral interferences may be of more importance than previously supposed in routine analytical situations. Further, there should be an optimal spectral bandpass for each analytical transition.
Visual and Automatic Spectral Analysis Using a Small Digital Computer
Authors: Akitt J. W.
Published: October 2005

A small computer, forming part of an NMR Fourier transform spectroscopy installation, has been programmed to analyze spectra consisting of overlapping lines such as are obtained from quadrupolar nuclei or in Raman spectroscopy. A rough visual fit to the data, which is displayed on an oscilloscope, is obtained by manual insertion of parameters and the fit is refined automatically using a sequential direct search method, thus eliminating the tedious stage of manual refinement. The equipment has proved easy and convenient to use.
Mixing of Ambient Nitrogen in a Flowing Argon Inductively Coupled Plasma Discharge
Authors: Barnes Ramon M. , Nikdel Seifollah
Published: October 2005

The concentration of argon and nitrogen are measured by gas chromatography for an inductively coupled plasma discharge in argon which is surrounded by a nitrogen sheath. The mixing of nitrogen with the argon discharge is substantially different than cold-gas mixing when no discharge is present. The formation of a toroidal discharge with a central flow further decreases the mixing of nitrogen with the discharge. More than a few percent nitrogen mixed into the argon discharge drastically alters the plasma temperature distribution.
Interaction of Silanes with Antimony Oxide to Facilitate Particulate Dispersion in Organic Media and to Enhance Flame Retardance
Authors: Pasteur G. A. , Schonhorn H.
Published: October 2005

Three new organo-antimony flame retardants which are insoluble in strong acid media have been prepared by the interaction of silanes with antimony oxide using three different procedures. These compounds have been characterized by infrared spectroscopy.
The Measurement of Oscillator Strengths for Copper Lines Involving Autoionizing Levels
Authors: McDermott William E. , Nash Charles P.
Published: October 2005

The relative oscillator strengths of lines involving levels subject to autoionization have been measured in an exploding wire. In this high electron density environment the depletion of the line strength due to autoionization is saturated. The relative oscillator strengths therefore approximate predicted values.
Atomic Fluorescence Spectrometry with an Eimac Continuum Excitation Source and a Graphite Filament Atomizer
Authors: Chuang F. S. , Winefordner J. D.
Published: October 2005

A graphite filament atomizer is used to produce atoms for a variety of elements, and the resulting atomic vapor is excited by means of an Eimac xenon arc continuum source. The resulting atomic fluorescence is measured by a conventional atomic fluorescence spectrometric instrumental system. Relative and absolute detection limits (sample size of 0.5 to 1.0 µl) are in the range of 2 × 10−4 to 0.1 µg/ml and 0.2 to 50 pg, respectively, for Ag, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, Tl, and Zn. Relative standard deviations (for four measurements) range from 0.03 to 0.07 for all of the above. The atomic fluorescence spectrometric system is simple and inexpensive to construct, simple to operate, and useful for a wide variety of elements without the need of changing any instrumental component or parameter other than the wavelength of the monochromator and possibly the conditions of atomization.
Polarization Scrambling by Optical Windows Used for Light Scattering Experiments at High Pressures
Authors: Cantor D. M. , Schroeder J. , Jonas J.
Published: October 2005

Polarization scrambling by high pressure cell windows as a function of pressure up to 2 kbar has been measured for two window materials and two sizes of plug apertures. Measured scrambling was about 1% for quartz, 0.5% for float glass, and decreased with decreasing aperture size. The amount of scrambling decreased significantly with time when the cell was left pressurized. A qualitative explanation of the results, based on changes in the P44 Pockets coefficient with pressure is given.
Identification of Oat Cultivars by Fluorescence Spectroscopy
Authors: Brach E. J. , Baum B.
Published: October 2005

A fluorescence spectrograph that operates in a reflective mode to identify oat cultivars is discussed. The wavelength of the exciting energy is 2400 Å, and the wavelength of the emission energy varies between 3000 and 5000 Å. Three peak and two valley points were identified and correlated with the different cultivars. A canonical analysis performed on various samples taken from six cultivars showed that they could be separated on the first two axes.