bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of the Internet to Obtain Cancer Information Among Cancer Patients at an Urban County Hospital
Authors: Helft Paul R. , Eckles Rachael E. , Johnson-Calley Cynthia Stair , Daugherty Christopher K.
Published: July 2005

Purpose

To evaluate rates, predictors, and barriers to use of the Internet to obtain cancer information among a cohort of cancer patients at an urban county hospital.

Patients and Methods

Of 208 cancer patients approached, 200 patients completed a structured interview study examining Internet use, perceptions of the accuracy of Internet information, and barriers to use.

Results

Only 10% of participants reported using the Internet themselves to obtain cancer information. Another 21% reported exposure to Internet information through proxies. The most common barrier to Internet use cited was lack of Internet access, with 44% reporting that they would use the Internet to obtain cancer information if they had Internet access. Younger age and more years of formal education were significantly associated with Internet use, although race and income were not. Less education, African American race, and female sex were associated with lower estimates of the accuracy of Internet information. Fewer years of formal education was associated with increased likelihood of reporting confusion after reading Internet information.

Conclusion

Very few cancer patients in this study of a cohort of generally disadvantaged individuals used the Internet themselves to obtain cancer information, although many more desired to do so. Significant opportunities for Web-based interventions aimed at improving cancer care outcomes in this population of cancer patients exist. However, further study will be needed to determine how to make such intervention accessible, trustworthy, and understandable to the disadvantaged.
Interteaching versus Traditional Methods of Instruction: A Preliminary Analysis
Authors: Saville Bryan K. , Zinn Tracy E. , Elliott Marcus P.
Published: July 2005

Interteaching is a new pedagogical method based on behavior-analytic principles; it includes elements of Keller's (1968) Personalized System of Instruction, reciprocal peer tutoring, and cooperative learning. We examined the effectiveness of interteaching relative to more traditional methods of instruction in a controlled laboratory setting. We randomly assigned participants to 1 of 4 conditions: interteaching, lecture, reading, or control. Participants in the interteaching group performed significantly better on a short multiple-choice quiz than participants in the other groups. Our results suggest that interteaching may be an effective alternative to other methods of classroom instruction.
Hedgehog signaling is required for cranial neural crest morphogenesis and chondrogenesis at the midline in the zebrafish skull
Authors: Wada Naoyuki , Javidan Yashar , Nelson Sarah , Carney Thomas J. , Kelsh Robert N. , Schilling Thomas F.
Published: July 2005

Neural crest cells that form the vertebrate head skeleton migrate and interact with surrounding tissues to shape the skull, and defects in these processes underlie many human craniofacial syndromes. Signals at the midline play a crucial role in the development of the anterior neurocranium, which forms the ventral braincase and palate, and here we explore the role of Hedgehog (Hh) signaling in this process. Using sox10:egfp transgenics to follow neural crest cell movements in the living embryo, and vital dye labeling to generate a fate map, we show that distinct populations of neural crest form the two main cartilage elements of the larval anterior neurocranium: the paired trabeculae and the midline ethmoid. By analyzing zebrafish mutants that disrupt sonic hedgehog (shh)expression, we demonstrate that shh is required to specify the movements of progenitors of these elements at the midline, and to induce them to form cartilage. Treatments with cyclopamine, to block Hh signaling at different stages, suggest that although requirements in morphogenesis occur during neural crest migration beneath the brain, requirements in chondrogenesis occur later, as cells form separate trabecular and ethmoid condensations. Cell transplantations indicate that these also reflect different sources of Shh, one from the ventral neural tube that controls trabecular morphogenesis and one from the oral ectoderm that promotes chondrogenesis. Our results suggest a novel role for Shh in the movements of neural crest cells at the midline, as well as in their differentiation into cartilage, and help to explain why both skeletal fusions and palatal clefting are associated with the loss of Hh signaling in holoprosencephalic humans.
Large-scale enhancer detection in the zebrafish genome
Authors: Ellingsen Staale , Laplante Mary A. , König Melanie , Kikuta Hiroshi , Furmanek Tomasz , Hoivik Erling A. , Becker Thomas S.
Published: July 2005

Murine retroviral vectors carrying an enhancer detection cassette were used to generate 95 transgenic lines of fish in which reporter expression is observed in distinct patterns during embryonic development. We mapped 65 insertion sites to the as yet unfinished zebrafish genome sequence. Many integrations map close to previously known developmental genes, including transcription factors of the Pax, Hox, Sox, Pou, Otx, Emx, zinc-finger and bHLH gene families. In most cases, the activated provirus is located in, or within a 15 kb interval around, the corresponding transcriptional unit. The exceptions include four insertions into a gene desert on chromosome 20 upstream of sox11b, and an insertion upstream of otx1. In these cases, the activated insertions are found at a distance of between 32 kb and 132 kb from the coding region. These as well as seven other insertions described here identify genes that have recently been associated with ultra conserved non-coding elements found in all vertebrate genomes.
Influence of Notch on dorsoventral compartmentalization and actin organization in theDrosophilawing
Authors: Major Robert J. , Irvine Kenneth D.
Published: July 2005

Compartment boundaries play key roles in tissue organization by separating cell populations. Activation of the Notch receptor is required for dorsoventral (DV) compartmentalization of the Drosophila wing, but the nature of its requirement has been controversial. Here, we provide additional evidence that a stripe of Notch activation is sufficient to establish a sharp separation between cell populations, irrespective of their dorsal or ventral identities. We further find that cells at the DV compartment boundary are characterized by a distinct shape, a smooth interface, and an accumulation of F-actin at the adherens junction. Genetic manipulation establishes that a stripe of Notch activation is both necessary and sufficient for this DV boundary cell phenotype, and supports the existence of a non-transcriptional branch of the Notch pathway that influences F-actin. Finally, we identify a distinct requirement for a regulator of actin polymerization, capulet, in DV compartmentalization. These observations imply that Notch effects compartmentalization through a novel mechanism, which we refer to as a fence, that does not depend on the establishment of compartment-specific cell affinities, but does depend on the organization of the actin cytoskeleton.
Primary health-care teams as adaptive organizations: exploring and explaining work variation using case studies in rural and urban Scotland
Authors: Farmer Jane , West Christina , Whyte Bruce , Maclean Margaret
Published: July 2005

It is acknowledged, internationally, that health-care practitioners' work differs between rural and urban areas. While several factors affect individual teams' activities, there is little understanding about how patterns of work evolve. Consideration of work in relation to local circumstances is important for training, devising contracts and redesigning services. Six case studies centred on Scottish rural and urban general practices were used to examine, in-depth, the activity of primary health-care teams. Quantitative workload data about patient contacts were collected over 24 months. Interviews and diaries revealed insightful qualitative data. Findings revealed that rural general practitioners and district nurses tended to conduct more consultations per practice patient compared with their urban counterparts. Conditions seen and work tasks varied between case study teams. Qualitative data suggested that the key reasons for variation were: local needs and circumstances; choices made about deployment of available time, team composition and the extent of access to other services. Primary care teams might be viewed as adaptive organizations, with co-evolution of services produced by health professionals and local people. The study highlights limitations in the application of workload data and suggests that understanding the nature of work in relation to local circumstances is important in service redesign.
Ring fencing of elective surgery: does it affect hospital efficiency?
Authors: Kjekshus Lars Erik , Hagen Terje P
Published: July 2005

Ring fencing (RF) is defined as separating elective from emergency operations in parallel hospital production lines. This study examines the effects of RF of elective surgery on hospital efficiency. The analysis is performed on two levels. First, an intensive three-month study at the departmental level of three hospitals was performed. Second, a panel data analysis of the organizational population of Norwegian hospitals over the period from 1992 to 2000 was conducted, using a 'fixed effect' regression model to analyse the effect of RF on hospitals' cost and technical efficiency. The intensive study indicates that RF could have positive effects both on cost and technical efficiency under certain conditions of case-mix and the demand for elective surgery, while the panel analyses of the effects of RF in the hospital population do not produce stable results. We cannot conclude that RF has unconditional positive effects on hospitals' efficiency. However, in certain situations of case-mix and demand for services, RF could be a valuable tool for managers to increase hospitals' efficiency.
Applying activity-based costing to the nuclear medicine unit
Authors: Suthummanon Sakesun , Omachonu Vincent K , Akcin Mehmet
Published: July 2005

Previous studies have shown the feasibility of using activity-based costing (ABC) in hospital environments. However, many of these studies discuss the general applications of ABC in health-care organizations. This research explores the potential application of ABC to the nuclear medicine unit (NMU) at a teaching hospital. The finding indicates that the current cost averages US$236.11 for all procedures, which is quite different from the costs computed by using ABC. The difference is most significant with positron emission tomography scan, US$463 (an increase of 96%), as well as bone scan and thyroid scan, US$114 (a decrease of 52%). The result of ABC analysis demonstrates that the operational time (machine time and direct labour time) and the cost of drugs have the most influence on cost per procedure. Clearly, to reduce the cost per procedure for the NMU, the reduction in operational time and cost of drugs should be analysed. The result also indicates that ABC can be used to improve resource allocation and management. It can be an important aid in making management decisions, particularly for improving pricing practices by making costing more accurate. It also facilitates the identification of underutilized resources and related costs, leading to cost reduction. The ABC system will also help hospitals control costs, improve the quality and efficiency of the care they provide, and manage their resources better.
Simulation of Current Waveforms in High Voltage Spark Sources III: Numerical Integration and Inclusion of Gap Dynamic Impedance
Authors: Scheeline Alexander
Published: July 2005

Procedures for simulating discharge currents and voltages in an adjustable waveform spark source are outlined, and comparisons are made between simulated and observed data. Bulirsch-Stoer numerical integration is used to allow solution of the requisite nine simultaneous differential equations. An approximate gap model is employed which demonstrates how dynamic gap properties may be incorporated into modeling. This provides a mechanism for coupling fundamental physical knowledge of gap processes to electrical engineering considerations in source design. Comparison to earlier work involving closed form solution of simpler models is made.
General Intensity Expression in Molecular Luminescence Spectrometry
Authors: van Geel F. , Voigtman E. , Winefordner J. D.
Published: July 2005

A general derivation of the luminescence flux reaching the detector in molecular luminescence spectrometry is given. The expression accounts for the pre-filter effect, the primary absorption effect, the re-absorption of fluorescence effect, and the post-filter effect. Also more than one absorbing species of primary excitation radiation and of fluorescence radiation is considered. The final expression may be used for explaining the shapes of luminescence analytical calibration curves in fluorimetry and phosphorimetry as well as to explain the mechanism of response of a positive-negative fluorescence detector.
Photoacoustic Spectroscopy of Rare Earth Oxides
Authors: Schoonover J. R. , Lee Yng-Long , Su S. N. , Lin S. H. , Eyring L.
Published: July 2005

A collection of photoacoustic spectra of several readily available stoichiometric rare earth oxide powders is presented. J levels of these spectra are assigned. In addition to the traditional applications of photoacoustic spectroscopy (chemical, physical, and analytical investigations), the technique is useful for studying the kinetics and thermodynamics of intermediate phases of rare earth oxides and surface photochemical reactions of rare earth oxides. The spectra may also reveal information on the lattice structure of powder grains. The need for additional work in rare earth oxide spectroscopy is pointed out.
The Vibrational Spectrum of Isotactic Polystyrene II: The Effect of Mass Defects
Authors: Painter Paul C. , Howe Stephen E. , Coleman Michael M.
Published: July 2005

Vibrational spectroscopic studies of isotactic styrene copolymers containing mass defects in the form of styrene-d8 units are presented. The results indicate that the changes which occur in the vibrational spectrum of isotactic polystyrene upon the introduction of styrene-d8 defects can be interpreted solely in terms of the derealization of chain vibrations and the appearance of localized defect modes. Frequency shifts and band broadening observed at low defect concentrations are shown to be consistent with an activation of the density of states of the protonated polymer.
Single Pulse Temperature Measurements in Flames by Thermally Assisted Atomic Fluorescence Spectroscopy
Authors: Elder Melanie L. , Zizak G. , Bolton D. , Horvath J. J. , Winefordner J. D.
Published: July 2005

Instantaneous single-shot temperatures measured using the thermally assisted fluorescence (THAF) technique are reported for three C2H2/O2/Ar flames which range in temperature from 2200 K to 2465 K. The temperature precision of 100 single-shot THAF measurements ranges, in general, from 10 K to 60 K. Comparison with averaged THAF temperature measurements and reversal temperature values indicates the high accuracy and precision obtainable with single-shot THAF and its potential for use as a thermometric method for laboratory and turbulent flames.
Fourier Transform Infrared Spectroscopy as a Powerful Tool for the Study of Carbohydrates in Aqueous Solutions
Authors: Back D. M. , Michalska D. F. , Polavarapu P. L.
Published: July 2005

FT-IR spectral investigations on carbohydrates were undertaken in aqueous media in order to facilitate the assignments of vibrational bands. For pure anomeric forms of glucose, FT-IR spectra obtained as a function of time revealed many changes in spectral content, providing new information about anomer characteristic bands in aqueous media. It was also found that fructose, which is known to undergo complex mutarotation, exhibits two types of spectral changes, whereas glucose, which undergoes simple mutarotation, shows a single type of spectral change. Thus FT-IR spectral investigations in aqueous carbohydrates should be able to distinguish between simple and complex mutarotation cases. As a vibrational spectroscopic technique, the importance of FT-IR spectroscopy is further emphasized by showing that Raman spectroscopy is not sensitive enough to reveal the structural changes of carbohydrates in aqueous media.
Application of Fourier Transform Infrared Emission Spectrometry to Surface Analysis
Authors: Nagasawa Y. , Ishitani A.
Published: July 2005

Infrared emission spectra of thin polymer layers on flat aluminum plate have been measured using Fourier transform infrared spectrometry. The detection limit of Fourier transform infrared emission spectrometry (FT-IR-EMS) was found to be comparable with that of Fourier transform infrared reflection absorption spectrometry (FT-IR-RAS) when an emission ray was collected at a viewing angle of 70°. The merits of FT-IR-EMS over FT-IR-RAS were demonstrated in the measurement of nonflat surfaces. The residual lubricant on steel tire cords could be detected efficiently by the FT-IR-EMS mode. The linear relationship found between the relative emission intensity and the thickness of film represents the possibility for a quantitative analysis of a thin overlayer on metal surface.
Spatial Emission Properties of a Microwave-Induced Plasma
Authors: Matousek J. P. , Orr B. J. , Selby M.
Published: July 2005

The spatial dependence of emission from a microwave-induced plasma in argon has been studied. A graphite furnace atomizer was used as a means of sample introduction. Emission from metallic elements is localized to a few cm near the inlet of the discharge, but the exact position of the emission profile is element-dependent. For non-metals, such as I, a broad profile centered about the resonant cavity is found. This difference in behavior is shown to be due to the deposition of metals upon the walls of the discharge tube used to confine the plasma. The removal of analyte atoms is explained by a mechanism which involves ionization of the analyte and then radial acceleration of these ions under the influence of the inhomogeneous microwave field. This hypothesis accounts for the observed decrease in emission intensity as microwave power is increased.
Infrared Study of Polystyrene at Variable Temperature
Authors: Nyquist R. A.
Published: July 2005

IR spectral data for polystyrene recorded at temperatures ranging from 30–210°C are reported. Certain IR band frequencies shift to lower frequency by as much as 4.5 cm−1 over the temperature range studied. In air, polystyrene oxidizes at 180°C.
Analytically Useful Spectra Excited in an Atmospheric Pressure Active Nitrogen Afterglow
Authors: Rice G. W. , D'Silva A. P. , Fassel V. A.
Published: July 2005

An atmospheric pressure active nitrogen (APAN) discharge has been utilized for producing characteristic molecular emissions from nonmetallic species introduced into the afterglow region of the discharge. The addition of inorganic S-, P-, B-, CI-, and Br-containing compounds into the afterglow has resulted in the formation of excited S2, PN, BO, NCI, and NBr species, respectively. Intense molecular Br2 emission and I2 emission, as well as atomic I emission, have also been observed. Preliminary analytical utilization of the molecular or atomic emissions observed revealed that the APAN afterglow may serve as a potentially useful detector for the aforementioned elements.
Circular Dichroism Measurements down to 600 cm−1
Authors: Polavarapu P. L.
Published: July 2005

Circular dichroism in vibrational transitions of chiral molecules is measured down to 600 cm−1, using a Fourier transform infrared spectrometer. This study indicates that the circular dichroism measurements can be carried out routinely to 600 cm−1.
Effects of Lightpipe Dimensions on Gas Chromatography/Fourier Transform Infrared Sensitivity
Authors: Giss Gary N. , Wilkins Charles L.
Published: July 2005

An empirical approach to the selection of lightpipes to achieve the best sensitivity for a particular GC column is presented. It is found that for a particular volume lightpipe the ratio of the length to the diameter determines the efficiency of the lightpipe. An empirical relationship that allows calculation of the most efficient lightpipe dimension is proposed.
Raman-Microsampling Technique Applying Optical Levitation by Radiation Pressure
Authors: Thurn R. , Kiefer W.
Published: July 2005

We report on a new Raman microprobe technique where micron-sized solid particles are trapped in stable optical potential wells using only the force of radiation pressure from a continuous gas laser. We demonstrate this technique with Raman spectra from spherical and non-spherical particles of sizes ranging between 10–30 μm. The particles are stably supported by a vertical directed focused TEM00-mode cw argon ion laser of ∼500 mW. The latter simultaneously serves as the exciting light source. Several suggestions for improvements of this technique are made.
Fourier Transform Infrared Vibrational CircularDichroism: Improvements in Methodology and Mid-Infrared Spectral Results
Authors: Lipp Elmer D. , Nafie Laurence A.
Published: July 2005

We report FT-IR-VCD recorded under improved conditions of signal-to-noise ratio, resolution, and spectral range (to 800 cm−1). Detailed descriptions are provided in the areas of artifact suppression, phase correction procedures, and comparison of FT-IR to dispersive VCD measurements. Spectral evidence supports the proposition that VCD absorbance artifacts are a surface effect originating at the optical window-solution interface.
Vibrational Spectra of Me2SiCl2, Me3SiCl, Me3SiOSiMe3, (Me2SiO)3, (Me2SiO)4, (Me2SiO)x, and Their Deuterated Analogs
Authors: Smith A. Lee , Anderson Dennis R.
Published: July 2005

This work had three objectives: to improve the reported assignments of the vibrational frequencies in several organoslllcon monomers and oligomers; to assign the vibrational frequencies of polydimethylsiloxane (PDMS); and to relate the vibrational spectra of PDMS to its other physical properties, especially at sub-ambient temperatures. Infrared and Raman spectra were obtained on the title compounds, and five sets of low-temperature IR spectra were obtained on PDMS. Some low-temperature spectra were also taken on the cyclosiloxanes. Assignment of all frequencies was accomplished, although in some cases, e.g., the methyl rocking frequencies at 650–870 cm−1 and the skeletal deformations below 400 cm−1, our confidence in their correctness Is less than complete. The low-temperature study showed striking changes In the IR spectrum of PDMS below its glass transition temperature T8. Bands became sharper and in some cases showed splitting. This behavior is consistent with the concept of polymer motion being frozen below T8. Except for the appearance of a strong, sharp band at 662 cm−1, not much change was seen in the spectrum at the “cold crystallization” point. Possibly the expected spectral changes were swamped by absorption from the more plentiful amorphous portion of the polymer matrix.
The Analysis of Lubricants on Magnetic Disks by Fourier Transform Infrared Spectroscopy
Authors: Walder Fredric T. , Vidrine D. Warren , Hansen George C.
Published: July 2005

The analysis of fluorocarbon lubricant on magnetic storage disks by Fourier transform Infrared external reflectance spectroscopy is presented. Optimization of parameters for the analysis is discussed and methods of quantitative analysis are proposed. Results from a dedicated accessory for the task are shown.
The Spectrochemical (ICP-AES) Determination of Tungsten in Tungsten Ores, Concentrates, and Alloys: An Evaluation as an Alternative to the Classical Gravimetric Procedure
Authors: Brenner I. B. , Erlich S.
Published: July 2005

A comparison is made of the precision and accuracy of the conventional WO3-gravimetric inductively coupled plasma atomic emission (ICP-AES) determination of macro amounts of tungsten in tungsten ores, concentrates, and alloys. Pure tungsten powders are readily dissolved in hydrogen peroxide. Samples having a complex mineralogical and metallurgical composition are conveniently dissolved by fusion with sodium peroxide and the solution stabilized with the employment of phosphoric acid. For ICP-AES analysis, the use of Sc(II) 361.384 as an internal standard reduces short-term variability by a factor of three, producing data that compare favorably with those obtained by the classical cinchonine-tungstic acid procedure and with those quoted in the literature for NBS 277.
Factor Analysis and Least-Squares Curve-Fitting of Infrared Spectra: An Application to the Study of Phase Transitions in Organic Molecules
Authors: Rao G. Ramana , Zerbi G.
Published: July 2005

The significance of eigenvectors and eigenspectra used in factor analysis, the relation of least-squares coefficients to the concentration of individual components, and the role of difference spectrum in the least-squares method have been examined theoretically. The equivalence of factor analysis and least-squares curve-fitting has been established. Factor analysis and least-squares curve-fitting have been attempted on the Fourier transform Infrared spectra of nonadecane, nonadecane-d2, nonadecane-d2 melt, and C24H49,COOH, obtained as a function of temperature. Experimental results have been used to substantiate theoretical conclusions.
Raman and Resonance Raman Spectroscopy of Selected Rare-Earth Sesquioxides
Authors: Tucker L. A. , Carney F. J. , McMillan P. , Lin S. H. , Eyring L.
Published: July 2005

Raman spectra of three readily available C-type stoichiometric rare-earth sesquioxide powders of composition Ln2O3 are presented. Some correlations of spectra with body-cell structure and infrared absorption spectra have been made. Spectra of Eu2O3, Dy2O3, and Tm2O3 display several new peaks that have not as yet been reported. Assignments of certain peaks to electronic Raman and resonance Raman transitions are discussed.
Infrared Spectra of Fossils
Authors: Low M.J. D. , Morterra C.
Published: July 2005

Infrared spectra of areas about 2.5 × 1 mm on the surfaces of fossil plant or animal remains can be recorded nondestructively with the use of photothermal beam deflection spectroscopy. Samples need not be removed from the fossil, which may remain on or in its matrix, as long as a portion of the fossil's surface is accessible to the analyzing beams. The technique is potentially valuable for the examination of special samples of palaeontological and archaeological interest.
Development of a New Optical Wavelength Rejection Filter: Demonstration of its Utility in Raman Spectroscopy
Authors: Flaugh Perry L. , O'Donnell Stephen E. , Asher Sanford A.
Published: July 2005

A new tunable optical filter has been developed which rejects a narrow wavelength interval (<7.5 nm) in the near-UV, visible, or near-IR spectral region and allows adjacent wavelengths to pass ( T > 90%). This filter will be useful in optics, in spectroscopy, and for laser applications. The active element of the filter is a crystalline colloidal array of polystyrene spheres. The rejected wavelengths are Bragg diffracted from this ordered array. For a particular sphere concentration and scattering from a particular set of lattice planes, tunability can be achieved by the altering of the angle between the filter and incident light beam. Bragg diffraction and light rejection of these filters are monitored by transmission measurements. The utility of this filter for spectroscopic measurements is demonstrated for Raman spectroscopy. Raman measurements are shown for polypropylene, a highly scattering material with numerous low-frequency modes. The filter selectively attenuates the elastically scattered light and allows the low frequency peaks to be observed. Use of this wavelength rejection filter to reject the Rayleigh scattered light simplifies the instrumentation, decreases the cost, and increases the sensitivity of Raman spectral measurements. This filter also has the potential to replace dispersive elements such as gratings and prisms in a variety of spectroscopic and optical applications.
Triplet-Triplet Absorption in Microcrystalline Benzil Detected by Diffuse Reflectance Laser Flash Photolysis
Authors: Wilkinson F. , Willsher C. J.
Published: July 2005

Following pulsed excitation at 354 nm, a transient absorption, maximizing at 510 nm, is readily observed for microcrystalline benzil, by diffuse reflectance laser flash photolysis. The transient absorption reduces the level of diffusely reflected analyzing light by 80%, and its decay appears to be a mixture of first- and second-order processes. Decay constants obtained from the slope of the first-order plot vary over a factor of about 2.5, with an initial slope = 0.18 × 105 (±0.01 × 10s) s−1, and a final slope = 0.66 × 104 (±0.04 × 104) s−1. Laser excitation also induces phosphorescence in microcrystalline benzil, which has a similar kinetic decay. It is confirmed that in diffuse reflectance mode the percentage transient absorption is directly proportional to the excited state concentration.
Photothermal Beam Deflection Study of Titanium Metal Corrosion by a Hot Lubricant
Authors: Masujima Tsutomu , Lloyd Lindsay B. , Eyring Edward M.
Published: July 2005

The applicability of the photothermal beam deflection (PBD) method in monitoring the corrosion of titanium metal by a perfluoropolyether lubricant was investigated in the 21°–270°C temperature range. The signal amplitude and rise time at lower temperatures (21°–150°C) were constant for a given amount of corrosion product. At higher temperatures (150°–270°C) thermal gradients in the sample cell caused correctable distortions of the PBD signal. The signal rise times in all cases were slow (1–2 s). Signal amplitude sensitivity to thermal gradients made kinetic measurements difficult, even on a long time scale. The PBD signal indicates that corrosion depends on the presence of molecular oxygen in the lubricant as well as upon temperature.
Chemical Dynamics of a Laser Microprobe Vapor Plume in a Controlled Atmosphere
Authors: Beenen G. J. , Piepmeier E. H.
Published: July 2005

The vapor plume produced by the action of a focused laser beam on a solid sample of an aluminum alloy or zirconium was studied in a controlled atmosphere. The formation of binary compounds by chemical reaction between the vapor plume and the atmosphere was followed with the use of emission, absorption, and fluorescence detection methods. Most experiments were performed at 150 Torr in 100% O2, 50% O2/50% Ar, and 100% Ar. Both spatially and temporally resolved profiles of the metal monoxide formed in the plume were recorded. The experimental data are compared to kinetic calculations for the formation of AlO and AlO2. The initial concentration of the atmospheric gas in the region of the plume was found to be less than the average bulk concentration in the sample chamber. A “piston” mechanism of plume expansion is proposed to account for this. Complete mixing of the plume with the atmosphere took at least 100 µs. A significant quantity of metal monoxide was formed in an atmosphere containing only trace amounts of oxygen. The sample is believed to be the source of oxygen.
Multichannel Coherent Anti-Stokes Raman Spectroscopy in Liquids
Authors: Adams V. S. , Carreira L. A. , Azakraga L.
Published: July 2005

A computer-controlled system has been developed for obtaining multichannel coherent anti-Stokes Raman (CARS) spectra of liquid samples. The technique utilizes a narrow (0.01 nm) pump laser beam and a partially broad-band (3–6 nm) probe laser beam. In addition to tuning the broad-band laser, a PDP 11/34 computer controls the crossing angle of the two beams, the collection angle of the multichannel output signal, and the tuning of a dispersive polychromator. Digital data are collected from a vidicon multichannel detector. CARS spectra of Rhodamine 6G (a highly fluorescent laser dye) and of perylene (a polyaromatic hydrocarbon of environmental interest) were obtained with the use of this system. The multichannel spectra are compared to those obtained from point-by-point scans.
Application of CARS to an Operating Chemical Reactor
Authors: England W. A. , Milne J. M. , Jenny S. N. , Greenhalgh D. A.
Published: July 2005

Coherent Anti-Stokes Raman Spectroscopy has been used to obtain in situ CO concentration profiles in an operating methanation reactor. The accuracy and precision of CO concentration measurement have been assessed with the use of least-squares fitting and a simple ratioing technique. The applicability of CARS to concentration measurements in chemical reactors is discussed.
Spatially Resolved Vibrational Temperature Profiles in Flames from Molecular Absorption Spectroscopy
Authors: Huie Carmen W. , Yeung Edward S.
Published: July 2005

A highly collimated laser beam is used to observe molecular absorption in a premixed air-acetylene flame by providing a two-dimensional image on a vidicon camera Spatially resolved molecular concentrations can thus be obtained in 1/60 second By measurement of the relative intensities of absorption from different vibrational levels in the ground state of the molecules, a vibrational temperature can be derived for each of the spatial regions in the flame This information is directly relevant to the understanding of dissociation in flames
Factor Analysis of Raman Spectra of Polyethylene under High Pressure
Authors: Shih L. B. , Priest R. G.
Published: July 2005

Raman spectra of very high signal quality in the skeletal optical region were obtained for linear polyethylene at three different pressures: ambient, 103 kbar, and 384 kbar We have employed the factor analysis technique to decompose a series of spectra at temperatures near the melt We found that there were two non-trivial abstract spectra for data at ambient pressure and 103 kbar and three non-trivial abstract spectra for the 384 kbar data The plots of the third reconstruction coefficients vs temperature gave scattered points in the first two cases and a structured curve in the case of the highest pressure Based on these observations, we conclude that there are two linearly independent contributions (crystalline and melt) to the two lower pressure data sets and three (crystalline, melt, and intermediate) to the highest pressure data set We believe this is the first piece of evidence for the existence of the high-pressure phase of polyethylene from spectroscopically derived measurements
Features of Infrared Emission Spectra of Organic Compounds
Authors: Baraldi Pietro , Fabbri Gianfranco
Published: July 2005

The IR emission spectra of a number of organic compounds have been examined in comparison with absorption spectra The behavior of band intensity as a function of some experimental parameters has been considered in order to find the optimum range of the parameters for the recording of the emission spectra It is shown that the spectra recorded on samples with low optical thickness and low crystal size are very close to absorption spectra Specific fields of application can be found where emission techniques exhibit some advantages in comparison with absorption ones
Purification of EDTA Monitored by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES)
Authors: Mitchell J. W. , Herring C , Bylina E
Published: July 2005

The viability and limitations of inductively coupled plasma atomic emission spectrometry (ICP-AES) for trace characterization of concentrated EDTA solutions are determined Qualitative detection of elemental impurities based on multielement scans, semiquantitative estimates of impurity levels obtained by comparison of results with calibration graphs in the 1 to 5 µg/mL range, and quantitative analyses via standard addition methods involving EDTA solutions doped with trace metals in the 01 to 10 µg/mL, and in the 001 to 016 µg/mL ranges are reported Applications of the method to the analysis of EDTA, purified by recrystallization, and to the monitoring of EDTA solutions, electrolyzed at the mercury cathode, are described Mercury cathode electrolysis is superior to the recrystallization method only in the case of removal of Cd, Cu, and Fe The recrystallization procedure provides the greater advantage of reducing the levels of a broader range of trace elements than was possible by electrolysis Both methods reduce amenable trace elemental impurities in EDTA solutions to the 100 ng/mL level or below
Decomposition of Copper Compounds in X-Ray Photoelectron Spectrometers
Authors: Klein Joseph C. , Li Chung Ping , Hercules David M. , Black James F.
Published: July 2005

Six Cu compounds were analyzed in three different x-ray photoelectron spectrometers (AEI-ES200, LHS-10, and HP-5950A), each equipped with a different type of AI Kα x-ray source, to determine the cause of reduction of copper salts in photoelectron spectrometers The monochromatic source used in the HP 5950A spectrometer did not cause sample degradation Significant sample degradation was observed in the AEIES200, which was attributed to the radiative heating from the x-ray gun The LHS-10 spectrometer, which utilizes a water-cooled x-ray housing, afforded significantly less sample reduction than the AEI ES200 spectrometer
Analysis of Gasifier Samples Collected with a High-Temperature/High-Pressure Cascade Impactor: Electron Spectroscopy for Chemical Analysis, Energy Dispersive X-Ray Analysis, and Scanning Electron Microscopy
Authors: Rothenberg S. J. , Brundle C. R. , Denee P. B. , Carpenter R. L. , Newton G. J. , Henderson R. F.
Published: July 2005

A particulate sample was collected from the process stream of a low Btu gasifier in a cascade impactor operated at 400°C and 10–12 atmospheres pressure. Stainless steel shim stock was used as collection substrate. The sample, which weighed less than 1 mg, was successfully mounted and examined by ESCA, EDXA, and SEM. The ESCA spectra of the samples and of the blank impactor plates were taken before and after ion etching. The SEM and EDXA data were obtained for samples still on the impactor plate and for a sample transferred from the plate to a carbon, oxygen, and sulphur, but no significant peaks for alkali metals or calcium normally found on the surface of coal combustion fly ash. The EDXA data demonstrated that the core of the particles contained Al, Si, Mg, Ca, and S. Methods of sample manipulation are described.
Determination of Boron in Silicate Geological Material by an Emission Spectrographic Method
Authors: Baucells M. , Lacort G. , Roura M. , Rauret G.
Published: July 2005

A spectrographic method has been developed to determine boron in silicate geological materials. Its basis is the use of a mixture (97.3%: 2.0%:0.7%) of graphite, gallium oxide, and germanium dioxide as internal standard, and the use of the 249.677 nm line to avoid interference of the SiO band. Standards were prepared by diluting 1:1 the synthetic glass VS-N (ANRT) with a synthetic silicate matrix. The precision of the method is 4.7%; we tested the accuracy by analyzing one geological international standard, which demonstrated good agreement between the standard and this technique. A new figure of glauconite GL-O boron content is given. Minimum detectable concentration is 11 μg/g B in rock sample.
Mixture Analysis of Fatty Amines and Their Derivatives by Carbon-13 NMR
Authors: Mozayeni Foad , Plank Charles , Gray Linsley
Published: July 2005

Fatty amines are derived from fatty acids and have varied industrial applications. When a mixture of these amines is analyzed, carbon-13 NMR can be used to provide specific structural information. This information can easily be used for quantitative analysis, making possible a clear and concise analysis of mixtures of these compounds.
Infrared Characterization of Different Water Types inside Reverse Micelles
Authors: Boicelli C. Andrea , Giominl Marcello , Giuliani Anna M.
Published: July 2005

The three Gaussian components of the IR stretching band of OH for reverse micelles of egg yolk L-α-phosphatidylcholine in benzene have been characterized in frequency, bandwidth, and extinction coefficient. The different types of water identified inside the micelles correspond to hydration layers around the phospholipid polar heads, the first containing up to ∼11 water molecules per polar head, the second with a maximum of 10–12 water molecules per polar head.
Some Effects of High-Solids Matrices on the Sample Delivery System and the Meinhard Concentric Nebulizer during ICP Emission Analyses
Authors: Baginski B. R. , Meinhard J. E.
Published: July 2005

Reports have challenged the viability of the concentric nebulizer for high-solids analyte injection in ICP spectrometers. Such samples, particularly those high in sulfates, have been said to cause emission signal drift and plasma instability due to salt deposits on the nebulizer nozzle tip which progressively obstruct argon supply to the plasma. It was of interest to test this hypothesis, particularly with respect to a comparison of the performance of a recently developed recessed capillary tip nozzle, the Meinhard Type C, with the performance of the widely used Types A and B. The aqueous test analyte contained 410 g/L hydrated aluminum sulfate with 1 mg/L manganese as internal standard. Nebulizer performance on a Perkin-Elmer ICP/5000 was monitored via the manganese emission signal and continuous readouts of the nebulizer argon flow rate and argon pressure. In each test, sample analyses continued to the point of plasma failure and instrument shutdown, after which the torch and nebulizer were removed and photographed. In all cases, failure due to salt deposits was discovered in the sample delivery tube of the torch, not in the nebulizers. However, the time before plasma failure occurred was significantly longer with the Type C nebulizer than with either the Type A or Type B units. Photographs and data tabulations are provided to illustrate these effects.
Vibrational Spectra of Species Adsorbed on Surfaces: Forms of Vibrations and Selection Rules for Regular Arrays of Adsorbed Species
Authors: Sheppard N. , Erkelens J.
Published: July 2005

In this paper we describe systematically the forms, symmetries, and selection rules for the normal modes of vibration of a number of examples of surface-adsorbed species. The chosen cases are discussed for adsorption both on isolated sites and in regular arrays of surface sites such as are occupied at higher coverage. For this purpose the Site Group and Factor Group (Correlation Field) approach to the vibrations of regular 3-dimensional lattices is adapted to the 2-dimensional systems. For simplicity the examples chosen are mainly monatomic and diatomic species adsorbed in various ways on specific sites of (111), (100), or (110) planes of metals with face-centered cubic lattices. The selection rules discussed refer to activities in infrared, Raman, or electron energy loss spectroscopy (dipolar and impact scattering mechanisms) and distinguish between adsorption on insulating and conducting (metal) surfaces. The examples chosen for regular arrays all refer to cases where experimental results (mainly from electron energy loss spectroscopy) are available in the literature, where they have been discussed mainly at the site group level.
Factor Analysis Applied to a Silane Coupling Agent on E-Glass Fiber System
Authors: Culler S. R. , Gillette P. C. , Ishida H. , Koenig J. L.
Published: July 2005

The system γ-aminopropyltriethoxysilane coupling agent on E-glass mats has been analyzed by the use of factor analysis to determine the number of pure components and extract the pure component spectra, to improve the signal-to-noise (S/N) ratio of the collected spectra, and to determine the concentration of unknown mixtures. Normalization of the scaling coefficients allows the construction of a calibration curve for the determination of the treating solution concentration by examination of the silane coupling agent on the glass mats.
X-Ray Fluorescence Analysis of Chinese Porcelains from K'ang Hsi to Modern Times Using Cd-109 Source
Authors: Yap C. T. , Tang S. M.
Published: July 2005

About 200 pieces of porcelains were analyzed with the use of the x-ray fluorescence technique with a Cd-109 source as exciter. It was found that fluorescence spectra of the glaze of porcelains made in Ching-te Chen during the Ch'ing dynasty and those made during the Republic period varied little. However, these spectra are quite different from those of the glaze of porcelains made elsewhere. Moreover, among porcelains made after World War II, those from Ching-te Chen and elsewhere often contain zinc and arsenic.
Calculation of Error in Depolarization Ratio Measurement Due to Finite Collection Angle in Laser Raman Spectroscopy
Authors: Deb S. K. , Bansal M. L. , Roy A. P.
Published: July 2005

We calculate the error introduced in the measurement of the depolarization ratio (ρ) of strongly polarized lines due to the finite angle of collection employed in a laser Raman spectrometer. The mathematical formulation takes explicit account of both the collection lens and the polarization analyzer, placed to select the polarization of the scattered beam. It is shown that for the commonly employed geometry where the analyzer is rotated by 90° to select the polarized and depolarized intensities, keeping the polarization of the incident beam normal to the mean scattering plane, the relative error (Δ ρ/ρ) does not exceed 8%, even for a collection cone of half angle as large as 25° for ρ as small as 0.01. The present work also shows that the results in the literature which suggest that the relative error in the depolarization ratio is independent of ρ are incorrect.
The Design and Characterization of an Interface for High Performance Liquid Chromatography with Direct Current Argon Plasma Detection
Authors: Mazzo David J. , Elliott William G. , Uden Peter C. , Barnes Ramon M.
Published: July 2005

The design and characterization of a nebulizer/spray chamber interface for high performance liquid chromatography-direct current argon plasma spectroscopy are presented. Optimum geometry for this interface was determined by the varying of the chimney tip diameter. Mechanical efficiencies of the interface as a function of nebulizer argon flow are tabulated. The particle velocity distribution within the solvent spray created by the nebulizer and emerging from the interface chimney was measured with the use of laser-Doppler anemometry.