bluuebunny/crossref_metadata_2025 huggingface dataset:
The Control of Errors in Infrared Spectrophotometry. VI. The Evaluation of Optical Constants by Combined Transmission and Attenuated Total Reflection Measurements
Authors: Goplen T. G. , Cameron D. G. , Jones R. N.
Published: August 2005

An improved technique is described for the determination of the optical constants of liquids in the infrared. It is based on a combination of transmission and attenuated total reflection (ATR) measurements. A novel application of the Kramers-Kronig transform function is involved whereby a single-valued integration constant is derived from a vector of refractive index measurements obtained by ATR. These are measured over a wavenumber range where the absorbance is low. It has been shown in earlier work that by an appropriate choice of a low refractive index contact material (in our case sodium chloride) the ATR method has high precision and accuracy under these conditions. The accuracy of the method is evaluated on the basis of a statistical treatment of the propagation of the estimated errors in the experimentally measured quantities, viz., the transmittance, the cell thickness, and the ATR measurements which establish the integration constant (anchor point) of the Kramers-Kronig transform function. The transmittance measurements are made at several cell thicknesses. The data reduction computer program, by which the optical constants are evaluated from the transmission measurements, monitors these sets of data and selects at each wavenumber the one having the minimal statistical error.
An Infrared Spectroscopic Flow Reactor for in Situ Studies of Heterogeneous Catalytic Reactions at High Temperature and the Reactions of CO2 and Benzyl Benzoate on Alumina
Authors: King S. T.
Published: August 2005

A simple infrared spectroscopic flow reactor has been fabricated for studying hetereogeneous catalytic reactions at elevated temperatures. Adsorption of CO2 on alumina and modified alumina catalysts shows the formation of several different surface carbonates. The hydrogen carbonate on alumina has a fast equilibrium with the gas phase. During the reduction of benzoic acid esters in this reactor, the formation of surface benzoate and carbonate has been observed. The desorption rate of the surface benzoate depends on the composition of the catalyst.
An X-ray Photoelectron (ESCA) and Laser Raman Spectroscopic Investigation of Aluminum Perrhenate
Authors: Salvati Lawrence , Jones Gerald L. , Hercules David M.
Published: August 2005

Compound formation in supported heterogeneous catalysts is an area of significant interest. In the present study, Al(ReO4)3 was prepared and characterized by x-ray photoelectron spectroscopy and laser Raman spectroscopy. Characteristic spectra for Al(ReO4)3 are shown and compared to several rhenium reference compounds. The reduction behavior of Al(ReO4)3 is also explored; it was completely reduced to elemental rhenium in H2 at 500°C.
Fluorescence of Optical Materials Stimulated by ArF Laser Radiation at 193 nm
Authors: Wren David J.
Published: August 2005

The fluorescence spectra of four optical materials (S1-UV quartz, UV grade sapphire, MgF2, and BaF2) have been recorded using ArF laser radiation at 193 nm (6.4 eV) as an excitation source. The time-resolved fluorescence intensities have also been measured at several wavelengths using a transient digitizer with 2 ns resolution. All of the materials exhibit a fast fluorescence which follows the exciting laser pulse and has a lifetime τR < 7 ± 2 ns. This fast fluorescence is present as a broad continum from 200 to 1000 nm with maxima in the UV and the IR. In addition, there are fluorescence components with longer lifetimes which are characteristic of the individual materials. The results suggest further opportunities for study of optical materials using ArF lasers and indicate an area of caution to be exercised by experimentalists employing ArF lasers for excitation experiments.
Frequency Modulation Applied to Stimulated Raman Scattering (SRS) for Linewidth and Temperature Measurement
Authors: Perkins P. E.
Published: August 2005

FM modulation is investigated as a technique for accurately measuring the linewidths of Lorentzian resonances observed by stimulated Raman scattering difference frequency tuning. A normalized linewidth is obtained from the ratio of the nth to the ( n + 1)th harmonic content of the detected signal. Possible applications in temperature measurement are discussed.
Raman Studies of the Adduct Structure of Cl2 and Br2 with Piaselenole
Authors: Blaha J. J. , Brittain W. , Meloan C. E. , Fateley W. G.
Published: August 2005

The affinity of 2,1,3-benzoselenadiazole, commonly called piaselenole, for chlorine and bromine molecules has been known for a long time. Raman spectroscopy provides a very interesting method for determining the molecular structure of these 1:1 adducts. The Raman spectrum shows the Cl2 and Br2 molecules in the adduct remain as a dimer molecule.
Coal Combustion Fly Ash Characterization: Electron Spectroscopy for Chemical Analysis, Energy Dispersive X-ray Analysis, and Scanning Electron Microscopy
Authors: Rothenberg S. J. , Denee P. , Holloway P.
Published: August 2005

The surface and bulk properties of five samples of fly ash have been examined by electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA). Samples from a conventional pulverized coal combustor, a conventional stoker-fed combustor, and an experimental fluidized bed combustor (FBC) were examined. ESCA data indicated that all samples contained silicon, aluminum, magnesium, calcium, iron, potassium, carbon, oxygen, and sulfur and all but one contained titanium. Samples from the conventional combustors contained more carbon than samples from the FBC. FBC samples contained large amounts of calcium and magnesium. Valence states of some elements were obtained by a detailed examination of selected ESCA peaks. Sputtering was performed on two samples to obtain a depth profile of the composition. The EDXA data confirmed the presence of silicon, aluminum, magnesium, calcium, iron, potassium, sulfur, and titanium while chlorine was detected in some samples. The EDXA data for individual particles exhibited marked particle to particle compositional variation. SEM studies demonstrated that the morphology of FBC samples was different from that of all of the conventional combustor samples examined.
Laser-Enhanced Ionization Spectrometry: Characterization of Electrical Interferences
Authors: Green R. B. , Havrilla G. J. , Trask T. O.
Published: August 2005

The electrical interferences associated with laser-enhanced ionization (LEI) spectrometry are characterized in this study. This was accomplished by comparison of LEI signal behavior in acetylene/air and hydrogen/air flames. A discussion of the relationship of the analytical signal and the total ion concentration in the flame is presented. The results of flame composition experiments are discussed as well as the role of matrix ions in determining signal strength. Experiments with modified sensing electrodes and higher applied voltages illustrate a partial remedy for electrical interferences.
Relaxation Spectrum of Polytetrafluoroethylene Obtained from Electron Paramagnetic Resonance and Nuclear Magnetic Resonance Spectra
Authors: Shimada Shigetaka , Tanigawa Takeshi , Kashiwabara Hisatsugu
Published: August 2005

Distribution of the correlation time in solid polymers was taken into consideration in the analysis of the magnetic resonance data. Motional narrowing of the line width of the EPR spectrum of fluoroalkyl radicals in polytetrafluoroethylene and that of broad line NMR spectrum (fluorine resonance) were observed on the same samples at the temperatures ranging from 260 to 320K. Since EPR and NMR measurements are measurements with different characteristic times of observation, representative correlation times corresponding to respective measurements were found to agree with the relaxation theory proposed by Miyake [J. Polym. Sci. 28: 476 (1958)] in which distributions of correlation time were taken into consideration. Based on these values, the real activation energy of the molecular motion associated with the motional narrowings of EPR and NMR studies were found to be 310 KJ/mol. On the other hand, the activation energy which gives the same relaxation spectrum as obtained from EPR and NMR data was found to be 318 KJ/mol. This reflects that the analysis in the present paper is a proper analysis. The present paper presents an example in which the consideration of the distribution of the correlation time was successfully applied.
Selective Detection in Gas Chromatography by Active Nitrogen-Induced Chemiluminescence
Authors: Melzer J. E. , Sutton D. G.
Published: August 2005

Previous work has clearly shown that metastable transfer emission spectrometry has useful applications as a general detector for hydrocarbon gas chromatography and as a detector for organometallic compounds. We report here additional progress in determining the characteristics of the system response to HCl catalyzed chemiluminescence from saturated hydrocarbons and to oxygen-containing compounds. The implications in terms of a multipurpose general and selective detector for chromatography are discussed.
Tunable Diode Laser Measurement of Hydrogen Cyanide in Smoke
Authors: Forrest G. , Vilcins G.
Published: August 2005

The development of a tunable diode laser system for the puff-by-puff determination of hydrogen cyanide is described. Both spectral line scanning and fixed-frequency monitoring techniques are utilized for quantitative measurements on mechanically diluted cigarettes. It is shown that such mechanical dilution leads to significantly greater reductions in hydrogen cyanide delivery than expected from static dilution measurements.
Fourier-Transformed Infrared Photoacoustic Spectroscopy of Solids
Authors: Rockley Mark G.
Published: August 2005

A wide selection of infrared absorption spectra of opaque samples is presented to show the versatility of Fourier-transformed infrared photoacoustic spectroscopy. A method for correcting these spectra for incident radiant power variations with respect to wavelength is also demonstrated.
A New Detection System of Saturation Transfer Electron Paramagnetic Resonance Spectroscopy by a Fourier Transformation Technique
Authors: Watanabe Tokuko , Sasaki Takayoshi , Sawatari Katsuhiko , Fujiwara Shizuo
Published: August 2005

A new detection system for measurement of accurate saturation transfer electron paramagnetic resonance (ST-EPR) spectra has been developed. The principle of this system is that the EPR absorbance is recorded digitally over a wide frequency range without filtering, then processed numerically by a Fourier transformation technique without any phase sensitive detector which is used in conventional ST-EPR spectroscopy. It is possible to acquire the first and second harmonic signals at in-phase and 90° out-of-phase simultaneously. To obtain very high accuracy of phase determination, the modulation signal is also recorded and processed digitally simultaneously. To improve the signal/noise ratio, an accumulation technique is adopted. Consequently, in-phase and 90° out-of-phase for 100 kHz modulation can be easily corrected within the ±0.5° accuracy, and the phase can be changed quantitatively. Experimentally it is shown that 90° out-of-phase has to be set within 90 ± 0.5° to suppress the out-of-phase signal under 1% of in-phase signal in the absence of saturation. The errors in the ST-EPR parameters and τ-values are also estimated in the case of improper phase angles.
A Computer-Spectrometer Interactive System for Infrared Spectroscopy
Authors: Edgell Walter F. , Schmidlin Edward , Balk Michael W.
Published: August 2005

Noise in the common kinds of infrared spectra in use today is considered. Statistics are employed to suggest modified spectra that have more desirable noise properties. A computer-spectrometer system for infrared spectroscopy is described with the novel feature that the computer modifies the scanning characteristics of the spectrometer as the data are acquired, permitting complete flexibility in programming the spectrometer's task. This system is able to control the spectrometer in the ways required to produce the modified spectra. The nature and operation of the electronic interface between the computer and the spectrometer are described together with the basic characteristics of the computer software used to program it. Several examples of the modified spectra are shown. Significant improvement in spectrum quality and run time is seen.
Bausch & Lomb-ARL: Where We Come From, Who We are
Authors: Eklund Robert L.
Published: August 2005

Remembering where we came from, points out author Alex Haley in Roots, helps us know who we are today. The roots of spectroscopy are closely intertwined with those of Bausch & Lomb-ARL, known to the industry for more than 45 years as Applied Research Laboratories. A member of Bausch & Lomb's Instrument Group, ARL today is a major multinational supplier of spectrochemical instruments in the optical emission, inductively coupled plasma (ICP), X-ray fluorescence and diffraction, microanalysis, and scanning electron microscopy fields. Its story begins with a graduate student's dream—which, unlike most dreams, came true.
The Use of Trigonometric Polynomials to Approximate Visible and near Infrared Spectra of Agricultural Products
Authors: Giesbrecht F. G. , McClure W. F. , Hamid Abdul
Published: August 2005

A Fourier analysis of the spectra consisting of 1000 to 2000 reflectance values obtained by scanning agricultural products at specific, equally spaced wavelengths is used to reduce the amount of data that needs to be recorded. It is shown that as few as 50 pairs of coefficients retain the bulk of the information contained in the complete spectrum. Using the limited number of Fourier coefficients is equivalent to rejecting the high frequency noise without spectral distortion and loss of data points at the ends of the spectra.
An Improved Pneumatic Concentric Nebulizer for Atomic Absorption. II. Aerosol Characterization
Authors: Routh M. W.
Published: August 2005

The aerosol droplets generated by a new pneumatic concentric nebulizer for flame spectrochemical applications are characterized. Droplet number density and size distributions were measured using low angle forward scattering of laser light and compared to aerosol density and size distributions for a conventional nebulizer. The effects of impact bead position, spray chamber droplet conditioning, burner head temperature, nebulizer driving pressure, and uptake rate on droplet size and number density, and atomic absorption response are presented. The observed improvement in response is a result of increased nebulizer efficiency in converting solution to usable aerosol.
Raman Spectrometry with High Sensitivity
Authors: Freeman J. J. , Heaviside J. , Hendra P. J. , Prior J. , Reid E. S.
Published: August 2005

Raman spectroscopy, for well-understood fundamental reasons, is a relatively insensitive method of analysis, i.e., it is problematic to study dilute solutions, gases at low pressures, adsorbed species, etc. We describe instrumentation incorporating exit slit plane “multiplex” detection and demonstrate that the instrument improves in sensitivity over its conventional counterpart by a significant margin (in this case >X1000). The value that this increased optical efficiency provides is demonstrated and new applications of Raman spectroscopy are discussed. We include a discussion of the factors controlling the efficiency of illuminating and viewing opaque or highly scattering samples sensitive to high brightness lasers and demonstrate that most commercial spectrometers are set up in such a way that they perform in these cases much less adequately than need be.
An Improved Pneumatic Concentric Nebulizer for Atomic Absorption. I. Design and Performance
Authors: Howarth H. , McKenzie T. N. , Routh M. W.
Published: August 2005

A new pneumatic concentric nebulizer for flame spectrochemical applications has been designed and evaluated. The construction and fundamental operational characteristics of two versions, fixed and adjustable uptake, are described. Analytical figures of merit including detection limits, characteristic concentrations, and precisions, obtained in conjunction with a conventional atomic absorption spectrophotometer, are presented. Improvements in sensitivity of approximately 40 to 50% are typical with no concurrent losses in precision. Performance characteristics of the adjustable uptake version with an organic solvent (methylisobutylketone) are also described.
Photoacoustic Measurement of Carbon Monoxide Using a Semiconductor Diode Laser
Authors: Vansteenkiste T. H. , Faxvog F. R. , Roessler D. M.
Published: August 2005

Photoacoustic measurements have been made at the 4.803 μm absorption line of carbon monoxide in a small nonresonant cell using a low power semiconductor laser source. A simple theoretical model correctly predicts the dependence of the CO signal on chopping frequency and concentration dependence but is inadequate in describing the pressure dependence. Concentrations as low as 50 ppmv were measured by operating the cell in a double pass mode.
Slurry Atomization dc Plasma Emission Spectrometry and Laser Diffraction Studies of Aerosol Production and Transport
Authors: Mohamed Norita , Brown Robert M. , Fry Robert C.
Published: August 2005

A clog-free Babington slurry nebulizer system is presented for direct current plasma (DCP) emission spectrometry. The DCP is unique in that the torch tip opening at the entry point into this plasma is presently ∼5 times wider than that of the inductively coupled plasma and ∼10 times wider than that of premixed flame burner slots. The combination of this enlarged DCP torch tip opening and a Babington slurry nebulizer results in an overall system for spectrochemical analysis that is virtually unrestricted as to the direct nebulization and aerosol transport of homogenized solid samples such as animal tissue. Beef liver is briefly homogenized for 2 min and then directly nebulized into the plasma. A sample may be nebulized continuously without torch tip clogging. This eliminates the need for transient nebulization and allows for extended electronic integration times as well as wavelength scanned, spectral background correction procedures. Elements such as Cu, Zn, Ca, and P are detected in liver tissue within less than 10 min from the time the unprepared solid sample is received in the laboratory. The effects of Babington gas orifice diameter, argon flow rate, and sample consumption rate are studied. The DCP is found to have a remarkably wide range of gas flow rates acceptable for nebulizer operation. The use of near forward laser Fraunhofer diffraction is reported for the direct measurement of droplet size distributions on a nonintrusive basis as the aerosols emerge from spray chambers of spectrochemical interest.
Emission Line Enhancement in a dc Plasma
Authors: Nygaard Danton D. , Gilbert Thomas R.
Published: August 2005

Emission line enhancement in a dc plasma seeded with an easily ionizable matrix salt is discussed. Enhancement is shown to be inversely related to the ionization potential of the matrix element. The temperature of the plasma core is shown to decrease in the presence of an easily ionizable element, while the effective temperature experienced by the analyte is shown to increase under the same conditions. The emission of the plasma is spatially profiled with and without an easily ionizable matrix element at the 425.4 nm Cr line, the 340.5 nm Co line, and the 334.5 nm Zn line.
Optical Artefacts and Their Control in Raman Circular Difference Scattering Measurements
Authors: Hug W.
Published: August 2005

The optical sources of artificial scattering differences plaguing Raman optical activity measurements, and the precautions to be observed to avoid them, are discussed in detail. The performance of a special light collection arrangement developed by us is analyzed and its effectiveness in suppressing artefacts demonstrated by experimental results, notably the first observation of genuine Raman optical activity in the C—H stretch region. This should pave the way to a more general application of Raman optical activity measurements in stereochemistry.
Negative Ion Mass Spectra of Organic Nitriles
Authors: Bush Kenneth L. , Parker Carol E. , Harvan Donald J. , Bursey Maurice M. , Hass J. Ronald
Published: August 2005

Negative ion mass spectra organic nitriles have been determined using 1 Torr of methane moderator/reagent gas in a chemical ionization source. The spectra contain abundant (M – 1)− ions, and fragmentations are minimal. Ion/molecule reactions with residual oxygen, methane, and between sample molecules and ions form diverse products with low abundances relative to the ( M – 1)−. Detection limits are comparable with positive ion methods, and for selected compounds, can be several orders of magnitude lower.
The Sensitivity and Limitations of Condensed Phase Infrared Emission Spectroscopy
Authors: Chase D. B.
Published: August 2005

The basic problems of condensed phase infrared emission spectroscopy are discussed. Conditions which cause instrumental background and the method for background removal are reviewed. The sensitivity of the technique is illustrated with spectra of microgram quantities. Spectra are shown for samples near room temperature (30°C) and for a sample below room temperature. The major limitations in infrared emission spectroscopy are reviewed and the problems associated with multiple passing of radiation through the modulator are outlined.
Molecular Symmetry and Two-Photon Spectroscopy
Authors: Wirth Mary J. , Koskelo Aaron , Sanders Matthew J.
Published: August 2005

Two-photon polarization spectroscopy is an established method for making excited state symmetry assignments in randomly oriented samples. The relationship between the two-photon absorption process and the symmetry of the excited state, as established by previous theoretical developments, is illustrated in terms of the principles of the interaction between polarized light and oriented symmetric molecules. A description of the experimental methodology is presented and several applications for which this method has been used in vibronic coupling studies are discussed.
Tunable Diode Laser Spectrophotometry: Measurement of Liquid Water Absorption Coefficients
Authors: Venkatesh C. G. , Eng R. S. , Mantz A. W.
Published: August 2005

A very accurate measurement of the absorption coefficient of liquid water using a tunable diode laser double beam spectrometer is presented. The water absorption coefficient is 123 ± 1.8 cm−1 at 2590 cm−1 obtained by nonlinear least squares fitting to an exact transmittance formula including the effect of multiple reflections at all four window surfaces, using only the nominal values of the refractive indices of water and window of ZnSe.
Calculation of Discharge Current Waveforms in High Voltage Spark Sources. I. Solution of Constant Parameter Model
Authors: Scheeline Alexander
Published: August 2005

Equations are derived for computing the current waveform and instantaneous power dissipation in high voltage spark sources containing a branched waveshaping network. For constant or dual valued circuit parameters, examples of waveform characteristics are presented. Limitations of this constant parameter approach are discussed, and suggestions made for application of the equations for simulating nonlinear source and discharge behavior.
Saturable Inductor Based Controlled Waveform Excitation Source for Exploding Thin Film Atomic Spectroscopy
Authors: Suh S. Y. , Collins R. J. , Sacks R. D.
Published: August 2005

An adjustable waveform excitation source for exploding thin film atomic spectroscopy is described. Waveform control is achieved through a saturable inductor having control windings and placed in series with the underdamped discharge tank circuit. This results in a high-current pulse for efficient sample atomization followed by a low-current measurement interval. When this is combined with gated integration, ∼15-fold increases in analysis line/background intensity ratios are observed for V and Mn. With additional inductance added to the circuit, the current and duration of both the atomization pulse and measurement interval can be adjusted independently. Other features of the excitation source include a plasma shunt capacitor, which results in more reproducible dielectric breakdown of the plasma support gas, and a variety of high-current series switches for initiating the discharge. Triggered spark gap, gravity operated spark gap, silicon-controlled rectifier, and ignitron switches are compared with respect to resistance and switching time jitter. Examples of discharge current and voltage waveforms and preliminary analytical data are presented.
Fourier Transform Infrared Evolved Gas Analysis: Additional Considerations and Options
Authors: Lephardt John O. , Fenner Robert A.
Published: August 2005

The technique of Fourier transform infrared evolved gas analysis described previously has been expanded both with respect to data processing options and to application areas. In this paper several of these additional options and applications are described. For improved qualitative and quantitative capabilities, smoothing and integration have been found beneficial. The use of interferometric processing permits compound specific profiles to be generated quickly. By considering reaction properties, the operations of spectral subtraction and factor analysis can be shown to yield information on both reaction stoichiometries and the number of reactions occurring vs temperature. In the area of applications, the examination of polymer chain length, functional group analysis, and intermolecular interactions are discussed.
Experimental Alignment of a Spectrometer System Using Laser Diffraction
Authors: Sainz Mario A. , Coleman David M.
Published: August 2005

A simple technique is described to facilitate precise three-dimensional alignment of a monochromator relative to a dimensionally fixed optical feed system. This technique uses diffraction of a He-Ne laser through the entrance slit of the monochromator. Diffraction pattern symmetry serves as a sensitive visual guide. Reduction of a three-dimensional alignment problem into a simpler two-dimensional one is achieved by the utilization of a “rail and rider” approach accompanied by systematic placement and mechanical alignment of components. Considerable time savings using this approach have been realized.
An Experimental Approach for Studies of the Photochemical, Thermal, and Environmental Degradation of Polymer-Coated Metals
Authors: Webb John Day , Schissel P. , Czanderna A. W. , Chughtai A. R. , Smith D. M.
Published: August 2005

An experimental approach to the study of polymer film photodegradation by Fourier transform infrared (FT-IR) spectroscopy, simultaneous with UV irradiation under varying thermal and environmental stresses, is described. Reflection spectra collected from polycarbonate-glazed gold mirrors undergoing irradiation in an environmental test chamber are presented as examples of the system's capability. The early degradative events in polycarbonate can be deduced from differences in these spectra.
Infrared Photoacoustic Spectroscopy of Conducting Polymers. I. Undoped and n-Doped Polyacetylene
Authors: Riseman Stephen M. , Yaniger Stuart I. , Eyring Edward M. , Macinnes David , Macdiarmid Alan Graham , Heeger Alan J.
Published: August 2005

Fourier transform infrared photoacoustic (FT-IR-PA) spectroscopy has been used to obtain the first published infrared spectrum of a heavily n-doped polyacetylene. Comparisons are made with the FT-IR-PA spectrum of undoped polyacetylene. All the infrared peaks in the FT-IR-PA spectrum of undoped polyacetylene agree in wavelength to ±10 cm−1 with transmission infrared peaks previously assigned by Shirakawa and Ikeda. Spectral shifts and intensity differences between the n-doped and undoped polyacetylene are similar to changes noted previously in the infrared spectra of p-doped polyacetylenes.
Total Internal Reflection Raman Spectroscopy at the Critical Angle for Raman Measurements of Thin Films
Authors: Iwamoto Reikichi , Ohta Koji , Miya Masaru , Mima Seiichi
Published: August 2005

Total internal reflection Raman spectroscopy at the critical angle has been shown to be useful for Raman measurements of not only thin films but also of any samples that can be directly coated or intimately contacted on the internal reflection element (IRE). Usefulness of this technique was demonstrated for a polystyrene film (0.70 μm thick) coated on the IRE, signal enhancement being 40 as compared with the conventional normal illumination. The technique was also applied to a thin coating layer of bovine albumin on the IRE to give the spectrum of excellent signal/noise ratio.
ICP-AES as a Multiple Element Detector for Metal Chelates Separated by HPLC
Authors: Fraley David M. , Yates Dennis A. , Manahan Stanley E. , Stalling David , Petty James
Published: August 2005

ICP-AES was used for the simultaneous multiple element detection of trace metals species separated by high-pressure liquid chromatography (HPLC). The technique is demonstrated for the determination of nitrilotriacetic acid (NTA) and ethylenedia-minetetraacetic acid (EDTA) chelates of copper, zinc, calcium, and magnesium. Multi-element chromatograms were obtained using a 32-channel polychromator programmed to perform a series of time-resolved intensity integrations. Data were retrieved channel-by-channel and plotted in histographic form. Comparison with UV absorbance and single-channel ICP-AES tracings reveals that the histograms reflect reliable chromatographic data. Linearity and precision of the system were found to be good in the 20 to 2000 ng range.
Spatial Dependence of Inverse Raman Signals
Authors: Daigneault Gregory R. , Morris Michael D.
Published: August 2005

The spatial dependence of inverse Raman signal intensities was investigated. Aqueous 0.5 M potassium nitrate in cells ranging from 1 to 50 mm was used as the test system. Three focusing lenses were used. The data do not fit the arctan dependence derived for Gaussian beams. The deviations are ascribed to the non-Gaussian profile of the pulsed dye laser beam.
Construction of a Compact Adjustable Waveform Spark Source
Authors: Thang Tran , Scheeline Alexander
Published: August 2005

An “open box” spark source is described. It is designed for easy adjustment of inductance and capacitance values while maintaining compact design to minimize radio frequency interference. The design allows monitoring of discharge parameters during operation, and can be assembled with minimal machining.
A Rotating Disk Cell for Raman Spectroelectrochemistry: Investigation of an Electrode Surface Species and an Electrogenerated Solution Species
Authors: Pemberton Jeanne E. , Buck Richard P.
Published: August 2005

A Raman spectroelectrochemical cell has been developed which incorporates a rotating disk design. This cell has been shown to be useful for the Raman investigation of electrode surface species (spinning electrode) and electrogenerated solution species (static electrode). It has been used to characterize the Raman spectroelectrochemical behavior of photolabile dithizone anion adsorbed at silver and copper electrode surfaces. Use of this cell for the study of electrogenerated solution species was demonstrated by the resonance Raman characterization of the tetracyanoethylene anion radical electrogenerated with a cyclic potential step. Cell construction is described and its merits discussed.
Near Infrared Atomic Emissions of Sulfur and Carbon in the Argon Inductively Coupled Plasma
Authors: Hughes Steven K. , Fry Robert C.
Published: August 2005

Inductively coupled plasma (ICP) excitation of the 9212.91 Å nonresonant line of atomic sulfur is reported and is found to yield a detection limit more than 20-fold better than any visible or “air path” ultraviolet sulfur lines produced by the argon ICP. The ICP excited spectrum reported here for the element sulfur is markedly different from that reported for atmospheric pressure microwave-induced helium plasmas. Partial Grotrian diagrams and tables of relative intensities, detection limits, and corresponding wavelengths of 30 ICP excited, nonresonant atomic sulfur emission lines and 20 ICP excited, nonresonant atomic carbon lines are presented for the air path, photomultiplier accessible region 2000 to 9900 Å. No lines of ionized sulfur were observed in the 27-MHz, 1.75-kW argon ICP. Vertical emission intensity profiles of near infrared S(I) and C(I) lines are presented for both conventional and extended ICP torches. The present near infrared (S(I) 9212.91 Å and C(I) 9094.83 Å) detection limits for sulfur and carbon are 0.006 μg and 0.13 μg, respectively, using 8 μL gas sampling loop injections of H2S and CH4 into a low-volume transfer line leading directly into the ICP.
Flame Temperature Measurement by Redistribution of Rotational Population in Laser-Excited Fluorescence: An Application to the OH Radical in a Methane-Air Flame
Authors: Zizak G. , Horvath J. J. , Winefordner J. D.
Published: August 2005

Expressions for the rotationally relaxed population densities, under steady state laser excitation, have been derived with particular concern to the temperature measurement in flames. Agreement has been found between the developed theory and the measured rotational distribution. The experiments were carried out with both a flash lamp dye laser (long pulses) and a nitrogen laser-pumped dye laser (short pulses). The two distributions were found identical, showing that fast collisional rate constants are involved in the relaxation of the OH radical in a methane-air flame. The thermally assisted fluorescence technique has been proved to give reliable results in combustion diagnostics.
Fourier Encoded Data Searching of Infrared Spectra (FEDS/IRS)
Authors: Azarraga L. V. , Williams R. R. , de Haseth J. A.
Published: August 2005

A new library searching technique is reported that relies on Fourier transforms of infrared (IR) absorbance spectra. Searching in the time domain is shown to be more tolerant to noise than searches in the spectral domain and fewer points are required to encode the unique characteristics of the individual spectrum. This decreases both search time and library storage requirements. Additionally, time-domain classification of IR spectra is demonstrated and the possibility of indexing the library for a binary search is discussed.
Liquid Core Optical Fibers in Raman Spectroscopy
Authors: Ross Howard B. , McClain William M.
Published: August 2005

Raman spectra of samples contained in hollow quartz fibers are compared quantitatively to conventional Raman spectra using identical laser, spectrometer, detector, and scan speed. We find the fiber signal to be enhanced by a factor of 250/m of fiber, in good agreement with calculations based on geometrical optics. A fiber spectrum of 2 mol% trans-stilbene in benzene is good enough to allow essentially perfect solvent subtraction.
Optical Depth of Field Effects in Particle Size Analysis by Laser Diffractometry
Authors: Mohamed Norita , Fry Robert C.
Published: August 2005

A nonlinear overestimate of the median droplet diameter measured by laser diffractometry in aerosols of interest in atomic spectrochemical analysis is found to result if the aerosol path traversed by the laser exceeds the optical depth of field characteristic of the diffractometer. The depth of field of a Leeds and Northrup diffractometer is found to be 4.4 cm. The magnitude of the error in apparent median droplet diameter is +21% for aerosols emergent from 10 cm slot burners used in flame spectrochemical analysis. Additional data are included for a variety of aerosol path lengths over the range 0.5 to 20 cm. Although a nonlinear overestimate in median diameter results from use of aerosol path lengths exceeding the optical depth of field (4.4 cm), no appreciable change in the width of the apparent droplet size distribution was found to occur for path lengths up to 18 cm.
Inductively Coupled Plasma-Atomic Emission Spectrometric Analysis of Environmental Samples Using Ultrasonic Nebulization
Authors: Taylor Charles E. , Floyd Terrance L.
Published: August 2005

Ultrasonic and pneumatic nebulizers used in inductively coupled plasma-atomic emission spectrometry (ICP-AES) are compared in the analysis of standard materials and environmental samples. Results verify that ICP-AES with ultrasonic nebulization is capable of lower detection limits than ICP-AES with a pneumatic system. The ultrasonic system used with desolvation, therefore, is the more desirable system when ultratrace ICP-AES quantitative analyses are required in a variety of environmental samples.
Extended Model for Saturation in a Two-Level System
Authors: van Dijk Cor A. , Omenetto N. , Winefordner J. D.
Published: August 2005

A model is presented, based on rate equations for a two-level system, which describes both the temporal and time-integrated dependence of the fluorescence signal due to saturation by a broad band and spatially homogeneous laser beam in an optically thin medium. In particular, we discuss the processing of the fluorescence signal by a gated integrator and relations between gate width, laser pulse length, and decay rate constant of the two-level system. It is shown that, even in the relatively simple case of a fully saturating, rectangular laser pulse, the integrated signal is still dependent on atomic and collisional parameters. On the other hand, this dependency can be used to measure these parameters. The only case in which the integrated signal becomes independent of these parameters is the case of a perfectly rectangular portion being sliced out of the time dependent fluorescence signal. An experimental method, which is expected to result in a better approximation of the saturation parameter in the case of the integrated signals, is suggested.
Experimental Determination of True Raman Linewidths from Measurements of Linewidths Observed at Different Slit Openings
Authors: Tanabe Kazutoshi , Hiraishi Jiro
Published: August 2005

A method is proposed to determine a true Raman linewidth from linewidths observed at different slit openings, without knowing accurate spectral slit widths. It is applied to various Raman lines of liquid molecules to assess the utility of the method.
Fourier Transform Infrared Spectroscopy of Protein Adsorption from Whole Blood: Ex Vivo Dog Studies
Authors: Gendreau R. M. , Winters S. , Leininger R. I. , Fink D. , Hassler C. R. , Jakobsen R. J.
Published: August 2005

A Fourier transform infrared/attenuated total reflectance technique has been developed to study protein adsorption onto surfaces. The application of this technique to an ex vivo model using a beagle dog as the source of whole, flowing blood is described (currently, high-quality infrared spectra are being collected at 5-s intervals of protein adsorption). This approach has enabled the authors to identify albumin and glycoproteins as the initially adsorbing species, with the subsequent competitive replacement of part of this protein layer with fibrinogen and other proteins. The exact relationship between the pattern of protein adsorption from whole blood and the generation of a thrombus (clot) is not yet clear, but it is hoped that this type of experimental approach will help clarify the relationship.
Applications of Four-Channel Raman Difference Spectroscopy
Authors: Laane Jaan , Kiefer Wolfgang
Published: August 2005

A four-channel photon counting system has been constructed for the measurement of Raman difference spectra. In this work we will describe the applications and advantages of such a system. Specifically, the simultaneous measurement of the parallel and perpendicular polarized compounds of the Raman spectra of both benzene and a mixture of benzene and benzene-d6 will be discussed. Spectra of two different mixtures of benzene and carbon disulfide and of the pure components were also recorded simultaneously using the four separate channels of the photon counting system. For both sets of data the solvent-induced frequency shifts were determined with very high accuracy.
Fabrication and Utilization of a High-Power Microwave Supply for Electrodeless Discharge Lamps and other Spectrochemical Emission Sources
Authors: Goode Scott R. , Baughman Kim W. , Pipes Dennis T. , Sandridge Michael R.
Published: August 2005

A study of the factors influencing the performance of a microwave-induced discharge shows that the analytical utility generally increases as the applied microwave power is increased. The fabrication of an easily used high-power system (500 W) is described; the system is used to excite electrodeless discharge lamps of relatively high-boiling species, multielement lamps, and an atmospheric-pressure flowing plasma. The system has been used to study vaporization phenomena in a cadmium electrodeless discharge lamp. The ground-state atom population, as measured by absorption, appears to be directly related to the thermal (wall) temperature.
EPR Study of Homogentisate Oxygenase from Aspergillus Sp.
Authors: Sonoda Masaru , Sakagishi Yoshikatsu
Published: August 2005

Homogentisate oxygenase from the fungus, Aspergillus, was isolated and partially purified. We used this enzyme for the EPR study of homogentisate oxygenase reaction. The strain of Aspergillus was isolated from soil in Saitama, Japan, and was cultivated in a medium containing ferrous iron and l-tyrosine as the sole carbon source. As well as the mammalian and bacterial homogentisate oxygenase, the fungal enzyme required ferrous iron as a cofactor, but not Fe3+, Cu2+, Co2+, or Mn2+. This fungal oxygenase was found to be very labile in the presence of O2. We performed EPR experiments on this homogentisate oxygenase reaction, and examined how the iron component was involved in oxidation of the substrate. When the homogentisate was added in an oxygen environment, an EPR signal of high spin iron (ferric) appeared at g = 4.28, which disappeared after incubation for 5 min at 25°C. Based on this result, we considered the oxygenation of homogentisate and proposed a reaction mechanism for homogentisate oxygenase from Aspergillus.
Deformation and fracture behavior of polypropylene–ethylene vinyl alcohol blends compatibilized with ionomer Zn2+
Authors: Montoya M. , Abad M. J. , Barral Losada L. , Bernal C.
Published: August 2005

This work investigated the deformation and fracture behavior of polypropylene–ethylene vinyl alcohol (PP/EVOH) blends compatibilized with ionomer Zn2+. Uniaxial tensile tests and quasistatic fracture experiments were performed for neat PP and for 10 and 20 wt % EVOH blends with different ionomer contents. The addition of EVOH copolymer to PP led to an increase in the Young's modulus whereas the yield strength was decreased with the EVOH content as a consequence of the higher stiffness of EVOH and the poor interfacial adhesion between PP and EVOH, respectively. Furthermore, the incorporation of EVOH into PP promoted stable crack growth. Neat PP displayed nonlinear load‐displacement behavior with some amount of slow crack growth preceding unstable brittle fracture, whereas most PP/EVOH blends exhibited “pseudostable” fracture characterized by slow crack growth that could not be externally controlled. All blends exhibited lower resistance to crack initiation than PP but the fracture propagation resistance was significantly improved. For 10 wt % EVOH blends, the resistance to crack initiation was roughly constant with the ionomer content up to 5%, then it increased with the further addition of compatibilizer. Conversely, for 20 wt % EVOH blends, the resistance to crack initiation appeared to be independent of the ionomer content. The better resistance to crack initiation exhibited by the 10 wt % EVOH blends could be attributed to a higher level of compatibilization in these blends. By contrast, 20 wt % EVOH blends with ≤2% ionomer content showed completely stable crack growth. In addition, J–R curves and valid plane strain fracture toughness values for these blends could also be determined. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1271–1279, 2005
Structure analysis in polyurethane foams at interfaces
Authors: Mahmood Nasir , Kressler Jörg , Busse Karsten
Published: August 2005

The aim of this study was to investigate the structure and morphology of polyurethane (PU) foams at the interface with a thermoplastic material. Fourier transform infrared/attenuated total reflectance spectroscopy was used to study the reaction of 4,4′‐diphenylmethane diisocyanate (MDI) with polyether‐based polyols with water as a blowing agent via the absorption intensity of the ν(NCO, 2265 cm−1) vibrational band of MDI in three different PU foam systems. The data revealed that MDI reacted simultaneously with two different species in the reaction mixture having different reaction rates. These were the reactions of isocyanate functional groups with water (fast reaction) and polyol (slow reaction). A structure analysis at the PU foam interface (i.e., PU formed a compact film 110 ± 30 μm thick at the interface) with a thermoplastic material plate was carried out with small‐angle X‐ray scattering (SAXS), transmission electron microscopy (TEM), and neutron reflection (NR) techniques. From SAXS measurements, a typical hard‐segment–segment distance of 10 ± 0.3 nm was observed. The TEM and NR data of the compact PU film revealed an internal layered structure (parallel to the surface) with a typical layer thickness of 260–400 nm. The formation of a layered morphology (macrophase‐separated structures) was assumed to be due to the difference in the polarities of the hard and soft segments. Furthermore, the layer thickness increased when D2O was used as the blowing agent instead of H2O. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1280–1289, 2005
Reactive polytetrafluoroethylene/polyamide compounds. I. Characterization of the compound morphology with respect to the functionality of the polytetrafluoroethylene component by microscopic and differential scanning calorimetry studies
Authors: Pompe G. , Häußler L. , Pötschke P. , Voigt D. , Janke A. , Geißler U. , Hupfer B. , Reinhardt G. , Lehmann D.
Published: August 2005

Compounds of electron‐beam‐irradiated polytetrafluoroethylene (PTFE) and polyamide (PA) were produced by reactive extrusion. During extrusion, both a breakdown process of the PTFE agglomerates and a chemical reaction between PTFE and PA took place. The morphology of the compounds was characterized with differential scanning calorimetry using fractionated crystallization, with atomic force microscopy and scanning electron microscopy, and with dynamic light scattering. The particle size of the dispersed PTFE phase decreased as the irradiation dose increased. A simple theoretical model of the breakdown process of PTFE agglomerates was made for the discussion of the development of the observed degree of dispersion. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1308–1316, 2005
Reactive polytetrafluoroethylene/polyamide 6 compounds. II. Study of the reactivity with respect to the functionality of the polytetrafluoroethylene component and analysis of the notched impact strength of the polytetrafluoroethylene/polyamide 6 compounds
Authors: Pompe G. , Häußler L. , Adam G. , Eichhorn K.‐J. , Janke A. , Hupfer B. , Lehmann D.
Published: August 2005

The formation of block copolymers as a result of an in situ chemical reaction during the reactive extrusion of electron‐beam‐irradiated polytetrafluoroethylene (PTFE) and polyamide 6 (PA) was detected indirectly with differential scanning calorimetry and Fourier transform infrared. As expected, the content of the block copolymers in the compound increased as the irradiation dose was increased. The notched impact strength showed an increase in the PTFE/PA compounds produced with highly irradiated PTFE. This behavior is discussed in the context of the degree of dispersion of the PTFE phase (as reported in part I of this series) and the adhesion changed by the in situ reaction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1317–1324, 2005