bluuebunny/crossref_metadata_2025 huggingface dataset:
Multielement Analysis of Rubber Samples by X-Ray Fluorescence
Authors: Kump Peter , Nečemer Marijan , Smodiš Borut , Jač'Imović Radojko
Published: August 2005

Destructive elemental analysis of rubber samples for major and trace element constituents is a rather demanding task, mainly because of the need for sophisticated and time-consuming sample preparation procedures. X-ray analysis has so far been used in the rubber industry primarily as a rapid tool for qualitative analysis, but a more realistic estimate of the accuracy of this, in many aspects, advantageous technique indicates that it could qualify as a quantitative method. In this work rubber samples were analyzed by the X-ray fluorescence analysis (XRFA) technique, utilizing Cd-109 and Fe-55 for excitation radioactive sources. The quantification procedure used employed a minimum number of calibration steps, utilizing only single-element-thick standards and stable compounds, or standard reference materials. Matrix correction calculations employed known fundamental constants and absorption measurements on a particular sample. In order to validate the results, and to establish the accuracy of analysis, some samples were also analyzed by neutron activation analysis (NAA). For the same purpose, the analysis of some standard reference materials of biological and inorganic matrices were performed. The accuracy of 5 to 6% achieved by XRFA means that it should be considered in the rubber industry as a rapid, simple, and cheap alternative to the analytical methods usually adopted.
Applications of a New 206.5-nm Continuous-Wave Laser Source: UV Raman Determination of Protein Secondary Structure and CVD Diamond Material Properties
Authors: Holtz Janet S. W. , Bormett Richard W. , Chi Zhenhuan , Cho Namjun , Chen X. G. , Pajcini Vasil , Asher Sanford A. , Spinelli Luis , Owen Philip , Arrigoni Marco
Published: August 2005

We demonstrate the utility of a new 206.5-nm continuous-wave UV laser excitation source for spectroscopic studies of proteins and CVD diamond. Excitation at 206.5 nm is obtained by intracavity frequency doubling the 413-nm line of a krypton-ion laser. We use this excitation to excite resonance Raman spectra within the π → π amide transition of the protein peptide backbone. The 206.5-nm excitation resonance enhances the protein amide vibrational modes. We use these high signal-to-noise spectral data to determine protein secondary structure. We also demonstrate the utility of this source to excite CVD and gem-quality diamond within its electronic bandgap. The diamond Raman spectra have very high signal-to-noise ratios and show no interfering broad-band luminescence. Excitation within the diamond bandgap also gives rise to narrow photoluminescence peaks from diamond defects. These features have previously been observed only by cathodoluminescence measurements. This new continuous-wave UV source is superior to the previous pulsed sources, because it avoids nonlinear optical phenomena and thermal sample damage; Photoluminescence.
Photosensitization by Harmine: An ESR Spin Trapping Study on the Generation of the Superoxide Anion Radical
Authors: Calle Paloma , Fernández-Arizpe Almudena , Sieiro Carlos
Published: August 2005

Harmine was in situ UV-irradiated in the presence of 5,5-dimethyl-1-pyrroline- N-oxide (DMPO), α-phenyl- N-tert-butyl nitrone (PBN), or α-(4-pyridyl-1-oxide) N-tert-butyl nitrone (4-POBN) as spin traps and observed by electron spin resonance (ESR) spectroscopy. The superoxide radical (O2·−) was detected as the corresponding DMPO, PBN, or 4-POBN spin adduct in dimethylsulfoxide (DMSO) or acetonitrile solution. The detection of these spin adducts was prevented by the addition of superoxide dismutase (SOD) to the solution. Also, the O2·− adduct formation was inhibited by the addition of antioxidants as cysteine methyl ester or ascorbic acid, in a dose-dependent manner. The studies carried out in aqueous buffered solution did not allow superoxide radical adduct detection. In the presence of DMPO as a spin trap, the DMPO–OH spin adduct was detected. On the other hand, classical scavengers of the hydroxyl radical such as mannitol or glycerol abolished DMPO–OH spin adduct detection. Other scavengers such as ethanol, DMSO, or sodium azide inhibited the trapping of hydroxyl radicals and resulted in the formation of new radical adducts. No PBN or 4-POBN spin adducts were detected in aqueous solution. The origin of the hydroxyl radical is discussed.
Investigation of YBa2Cu3O7-δ Superconducting Ceramics Intergranular Bonds with the Method of Nonresonant Microwave Adsorption
Authors: Makarshin L. L. , Belousov N. S. , Parmon V. N.
Published: August 2005

By the use of the electron spin resonance (ESR) method, the relation of intra- and intergranular components in a nonresonance microwave adsorption signal was investigated for superconducting YBa2Cu3O7-δ samples. It is shown that different kinds of external influences on superconducting ceramics (annealing in oxygen at 500 °C and paramagnetic molecule adsorption onto the ceramics) lead to the enhancement of intergranular bonds, while the granular properties are scarcely affected by these treatments.
Paramagnetic Centers and Dopant Excitation in Crystalline Silicon Carbide
Authors: Gerardi Gary J. , Poindexter Edward H. , Keeble David J.
Published: August 2005

Impurities, point defects, and dopant excitation in SiC have been examined by electron paramagnetic resonance (EPR). The pervasive nitrogen n-type dopant was found to show a substantial photo-enhancement, not due to generation of carrier pairs. Aluminum in Al-doped SiC showed a strong EPR signal below 4 K, which disappeared as the sample was warmed to 10 K, because of the onset of impurity band conduction. The Al EPR signal intensity depends on the degree of compensation. Boron EPR appeared in samples where excess Al counteracts the compensation of B ions by N dopant. Hydrogen plasma anneal at 250 °C partially passivated Al; however, extended heating in vacuum, expected to depassivate, actually further decreased the Al signal. Abrasion damage produced a featureless, isotropic signal suggestive of the bulk damage signal in Si, indicating dangling C or Si orbitals. An oxide interface signal, in analogy to Pb of oxidized Si, was not isolated; the observed signal included a damage-like line.
Self-Association of Medium-Chain Alcohols in n-Decane Solutions
Authors: Førland Geir M. , Libnau Fred O. , Kvalheim Olav M. , Høiland Harald
Published: August 2005

Self-association of medium-chain alcohols in n-decane solutions has been studied by infrared absorption of the fundamental OH stretching vibration. The alcohols investigated were 1-propanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-butanol, 1-pentanol, and 1-hexanol. Infrared spectra were acquired for varying alcohol molalities, the highest concentration being 0.2 mol/kg. The spectra for each alcohol were collected in a data matrix. The bilinear multicomponent data were successfully resolved into spectra and concentration profiles by a multivariate method. The result indicates that monomers dominate the spectral variance in the low-molality region, while cyclic oligomers dominate in the upper concentration range. It further indicates that minor amounts of open-chain aggregates may be present. The monomer and cyclic tetramer appear to be the dominant species, while the amount of open-chain aggregates was negligible even in the low-molality region. The equilibrium constants for the monomer–tetramer association reactions ( K1–4) were calculated by a least-squares method. The calculated values for the equilibrium constants, based on the molality, range from 138 to 106 for the linear alcohol molecules. The result shows that 1-butanol, 1-pentanol, and 1-hexanol have similar constants, while 1-propanol displays a markedly higher value. The equilibrium constants obtained for 2-methyl-1-propanol and 2-methyl-2-propanol were 77 and 39, respectively. The considerably lower values for the branched alcohol molecules indicate that steric interaction between the chain prevents self-association into larger aggregates.
Laser-Induced Fluorescence in Artwork Diagnostics: An Application in Pigment Analysis
Authors: Anglos Demetrios , Solomidou Maria , Zergioti Ioanna , Zafiropulos Vassilis , Papazoglou Theodore G. , Fotakis Costas
Published: August 2005

The applicability of laser-induced fluorescence (LIF) spectroscopy as a nondestructive analytical technique for artwork diagnostics is investigated. In this work, LIF is employed in the examination of a set of cadmium sulfide- and cadmium selenide sulfide-based pigments in a series of oil painting test samples. Fluorescence spectra of the oil colors are recorded upon pulsed laser excitation at 532, 355 (Nd:YAG), and 248 nm (KrF excimer). The technique is shown to be suitable for differentiating among the various cadmium pigments used in this study and, furthermore, to be capable of identifying individual components in mixtures of these pigments on the basis of their characteristic fluorescence emission. Future prospects and the potential for the extension of LIF from a research laboratory technique into a conservator's tool for artwork diagnostics are discussed.
Equilibrium Vapor Cell for Quantitative IR Absorbance Measurements
Authors: Field Paul E. , Combs Roger J. , Knapp Robert B.
Published: August 2005

Infrared absorbance measurements through a gas flow cell are made with the closed-loop circulation of vapor/air mixtures equilibrated with the use of temperature-regulated aqueous solutions. Constant reproducible vapor pressures of organic solutes are established with the equilibrated aqueous solutions. The water solvent depresses the vapor pressure of the pure organic solutes of methanol, ethanol, isopropanol, acetone, and methyl ethyl ketone (MEK). Knowledge of the solution liquid mole fractions, the pure component vapor pressures, and the Wilson coefficients permits determination of the solute vapor pressures to within 2% accuracy. Reliable aqueous solution preparation requires only the correct weighings of pure constituent materials before mixing to achieve the targeted solute liquid mole fractions. Absorbances are measured for four of the five solutes over a range of seven concentrations and for MEK over four concentrations. These concentrations show the absorbance region of adherence to Beer's law with an experimental precision of approximately ±2% for the solutes studied. Absorptivities that are calculated from the Beer's law slope are compared to the available infrared absorbance data.
FT-IR Analysis of Pillared Clay Pore Structure via Adsorbed Bipyridine Surface Probe Species
Authors: Bagshaw Stephen A. , Cooney Ralph P.
Published: August 2005

Adsorption interactions of the bidentate molecules 2,2'-bipyridine and 4,4'-bipyridine with the surfaces of different alumina-pillar interlayered clays have been investigated by FT-IR spectroscopy. These interactions were examined in an attempt to establish a spectroscopic method for the determination of interpillar distances in the galleries of pillared clays. 2,2'-Bipyridine adsorbs in a bidentate C2 v, interaction to single Lewis acid sites on the surfaces of individual pillars and not to adjacent pillars, indicating that the distances between binding sites on adjacent pillars are too great to be successfully probed by this molecule. 4,4'-Bipyridine maintains the D2 h symmetry of the free molecule through interaction with Lewis acid sites on two adjacent pillars simultaneously via both ends of the molecule, thereby exhibiting possible utility as a probe of the interpillar distance. Surface-adsorbed monoprotonated 2,2'-bipyridinium cations are formed through interaction with Brönsted acid sites on the pillared clay surfaces. The IR spectrum of the surface-adsorbed protonated species suggests C2/i transoid symmetry and is presented for the first time.
Phase Retrieval in Optical Spectroscopy: Resolving Optical Constants from Power Spectra
Authors: Vartiainen Erik M. , Peiponen Kai-Erik , Asakura Toshimitsu
Published: August 2005

The problem of phase retrieval appears in optical spectroscopy when a power spectrum P(ω) = |f(ω)|2 is measured while the entire complex function f(ω) = | f(ω)|exp iθ(ω) is needed for obtaining the desired material properties. Recently we proposed a new approach to solve this problem in optical spectroscopy by using the maximum entropy model. Here we give a short review of its theory and show how to improve the phase retrieval procedure to work well in practice. The usage and applicability of the procedure, especially in reflectance spectroscopy of solids, are demonstrated with practical examples. Its use in other applications is also discussed.
Spectroscopic Characterization and Tissue Imaging Using Site-Selective Polyazacyclic Terbium(III) Chelates
Authors: Houlne Michael P. , Agent Tony S. , Kiefer Garry E. , McMillan Kenneth , Bornhop Darryl J.
Published: August 2005

Polyazamacrocyclic chelates of terbium are shown to be useful in diagnostic medical imaging as tissue site-selective markers. Spectroscopic properties and biodistribution are studied for three terbium(III) species: 3,6,9-tris(methylene phosphonic acid n-butyl ester)-3,6,9,15-tetraaza-bicyclo[9.3.1]pentadeca-1(15),11,13-triene (abbreviated as PCTMB); 3,6,9-tris(methylene phosphonic acid)-3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(13),11,13-triene (abbreviated as PCTMP); and N,N'-bis(methylene phosphonic acid)-2,11-diaza [3.3]-(2,6)pyridinophane (abbreviated as BP2P). The respective aqueous molar absorptivities are found to be 3424, 2513, and 3281/2210 L mole−1 cm−1. Fluorescence quantum efficiency is determined against rhodamine 19 in basic ethanol and rhodamine 6G in ethanol. These values are 0.48, 0.21, and 0.40 for Tb-PCTMB, Tb-PCTMP, and Tb-BP2P, respectively. Biodistribution studies performed in Sprague–Dawley rats indicate tissue site-selectivity. Fluorescence images of bone tissues are presented and demonstrate the potential for using the lanthanide chelates to perform site-directed in vivo imaging for the early identification of abnormal tissue.
Quantitative Depth Profiling of Layered Samples Using Phase-Modulation FT-IR Photoacoustic Spectroscopy
Authors: Jones Roger W. , McClelland John F.
Published: August 2005

In phase-modulation FT-IR spectroscopy, all wavelengths in a spectrum are modulated at the same frequency and in phase. This factor makes the use of photoacoustic phase data for depth profiling samples much easier in phase modulation than in rapid scan. A method to quantitatively measure layer thickness by using the phase of a substrate spectrum peak is demonstrated with a series of samples consisting of thin polymer Alms on substrates. Additions to the basic method are demonstrated that extend its application to cases where the substrate peak is overlapped by a spectrum peak of the surface film. A linear relationship between phase angle and layer thickness extending to thicknesses greater than twice the thermal diffusion length is demonstrated. Representations of phase modulation data as a family of angle-specific spectra, as magnitude vs. phase curves, and as a power spectrum and phase spectrum pair, each of which is useful for different aspects of depth profiling, are discussed. Calculating these representations from a single pair of orthogonal interferograms is described.
Determining Acid Equilibrium Constants by Means of Chromatic Parameters
Authors: Escolar D. , Haro Ma R. , Saucedo A. , Ayuso J. , Jimenez A. , Alvarez J. A.
Published: August 2005

A method has been developed for the determination of acid-base equilibrium constants, which is applicable to compounds that absorb in the visible. The tristimulus (X, Y, Z) and the colorimetric coordinate values ( L, a, b) of the chromatic space CIELAB 1976 are calculated by means of the transmittances of the entire spectral range. The curves, in the a,b plane, of chromatic differences vs. pH intersect at a pH value agreeing with the p Ka; this configuration occurs because a chromatic equilibrium of both species takes place at this point, which corresponds to the chemical equilibrium. With this method, the acidity constants are found easily and quickly, and they yield very good results. The validity of the method has been tested with the acid-base indicator bromophenol blue, obtaining p Ka= 3.943 at 25 °C; this result is compared with those obtained through the usual spectrophotometric methods. Also, thermodynamic magnitudes obtained from p Ka values at different temperatures from 20 to 70 °C have been determined, resulting in Δ H0 = -(13.93 ± 0.88) kj mol−1 Δ S0 = -(122.6 ± 2.8) J K−1 mol−1.
Comparative Study of the Solid-Matrix Luminescence Properties of Perdeuterated Phenanthrene and Phenanthrene Adsorbed on Several Solid Matrices
Authors: Ramasamy Savakkattupalayam M. , Hurtubise Robert J.
Published: August 2005

Temperature was varied over a wide range to determine its effect on the luminescence properties of deuterated phenanthrene and phenanthrene adsorbed on a number of solid matrices. Not only were insights into the effects of temperature and solid matrices on the luminescence properties acquired but also the deuterium isotope effect revealed unique information about the role played by the solid matrix in the luminescence of the model compounds. In addition, comparisons of nonradiative rate constants and the efficiencies of intersystem crossing revealed important differences among the solid matrices in altering these parameters. The perdeuterated phenanthrene and phenanthrene proved to be useful probes for investigating the effects of solid matrices on the excited triplet state of phosphors because the excited singlet state of the lumiphor was affected very little by the solid matrices, and the rate constants of phosphorescence for the two phosphors are essentially the same.
Cut Performance Fundamentals and Norms Harmonization
Authors: Rebouillat S , Steffenino B
Published: August 2005

The cut performance of articles made of high performance materials is currently evaluated using several norm procedures. These tend to diverge, in their predictiveness of the “real” in use performance of the considered protective articles, when the cut resistance of the compounding fiber increases. Although relationships exist between the various cut performance levels obtained using ASTM, ISO, and EN norms, the ASTM and ISO approaches remain the most suitable methods for cut level exceeding 3, as defined by the European EN388 standard, this normalized cut resistance measurement procedure is part of the ANSI/ISEA 105-2000 guidance. Various studies, such as the effect of the cutting speed and the speed profile, the force distributions, the artefacts generated by various spot coatings, etc., aim at improving the interpretation of the measured cut level. Therewith, substantial potential improvements of the cut fundamental understanding and the norm harmonization are brought to the attention of the end-users of mechanically resistant articles made of high performance fibers, such as para-aramid.
Obtaining Creep Compliance Parameters Accurately from Static or Cyclic Creep Tests
Authors: Kim J , Roque R , Birgisson B
Published: August 2005

Obtaining creep compliance parameters that accurately represent the creep response of asphalt mixtures is critical for proper evaluation of the thermal cracking performance, as well as load induced cracking performance of asphalt pavements. A power law, which uses three parameters to describe the creep compliance curve, is commonly used for asphalt mixtures. However, the specific values of the parameters obtained can depend on both the testing and the data interpretation methods used. Different testing methods (for example, static versus cyclic creep) offer different advantages and disadvantages related to complexity in testing, as well as in the sensitivity of the data obtained from each test to the compliance parameters of interest. In general, cyclic creep tests provide greater sensitivity and accuracy at shorter loading times, while static creep tests are more accurate and reliable for the determination of the long-term creep response.
Post-Irradiation Tensile Behavior and Residual Activity of Several Ferritic/Martensitic and Austenitic Steels Irradiated in Osiris Reactor at 325°C up to 9 dpa
Authors: de Carlan Y , Averty X , Brachet J-C , Bertin J-L , Rozenblum F , Rabouille O , Bougault A
Published: August 2005

An experimental irradiation, named “Alexandre,” has been carried out in the Osiris experimental reactor to perform a generic study on the mechanical behavior after irradiation at 325°C of different kinds of steels suitable for use as irradiated components in a nuclear reactor [1]. The irradiated steels were austenitic stainless, martensitic (conventional and reduced activation), and ferritic-martensitic Oxide Dispersion Strengthened steels in various initial metallurgical conditions. The final dose was 9 dpa, which represents nearly a “saturation” dose for the hardening/embrittlement of both austenitic and martensitic steels. At this dose, the Yield Strength and the Ultimate Tensile Strengths are almost equal, and strong localization of the plastic deformation is often observed.

After irradiation, as-quenched martensitic steels exhibit very large tensile strengths, and some of them show ductility parameters comparable with those of the tempered martensitic steels. At 9 dpa, the behavior of cold-worked steels tends to be similar to that of tempered steels with a more pronounced localization of the deformation. This indicates that the recovery of the cold-worked microstructure is not achieved at 9 dpa. Certain martensitic steels (MANET II and HT9) show tendencies to brittle behavior and exhibit a considerable degradation of their ductility parameters after irradiation. The behavior of the most chromium-rich ferritic steel (ODS-MA957) is quite surprising. It exhibits moderate hardening and good post-irradiation ductility parameters.

Measurements of the dose rate have been performed after several cooling-times, of up to 53 months after unloading, to study the radioactive decay of the steels. Experimental data show that the reduced activation steels exhibit the lowest residual activity and the highest rate of relative activity decrease (90 %) during the cooling period.
Delayed Hydrogen Cracking Velocity and J-Integral Measurements on Irradiated BWR Cladding
Authors: Grigoriev V , Jakobsson R
Published: August 2005

Propagation of an axial crack has been characterized by means of the Pin-Loading Tension (PLT) test. The same experimental arrangement is used for the Delayed Hydrogen Cracking (DHC) and for the J-integral measurements. The DHC tests are performed under variable temperature and/or load conditions simulating a variable PCMI. Tests have been performed in air on unirradiated SRA Zircaloy-4 tubing and irradiated BWR Zircaloy-2 cladding containing from 30–350 ppm of hydrogen. Variable loading facilitates DHC: in the experiment at 300°C a crack velocity as high as 9.3·10−7 m/s (80 mm/day) has been observed for irradiated cladding. V-K curves or diagrams of DHC crack velocity, V, as a function of stress-intensity factor, K, are suggested for different BWR claddings. Despite a limited amount of tests, the V-K curves appear to depend on the type of cladding. DHC does occur at much lower stress intensities compared to the Kc converted from the J0.2 values, confirming DHC to be the dominating secondary failure crack propagation mechanism in BWR cladding.
Effect of Installation Details on the Condensation Performance of Window Frames
Authors: Kudder RJ , Babich SK , Johnson DK
Published: August 2005

Industry standard tests and calculation methods under laboratory conditions are used to determine a Condensation Resistance Factor (CRF) for window frames. The CRF is one of several performance parameters used to select fenestration products for specific conditions of exposure and occupancy. Colder climates and higher interior humidity typically require fenestration products with higher CRFs. The CRF by itself is not necessarily a predictor of the ability of a window frame to resist interior surface condensation due to thermal bridges or breaches in thermal breaks created by installation details, rough opening materials, and surrounding wall details. This paper explores the affect of installation details on the interior surface temperature of metal window frames, and indirectly, the likelihood of surface condensation on the frame.
Corrosion Resistance, Mechanical Properties, Fatigue Properties, and Tissue Response of Ti-15Zr-4Nb-4Ta Alloy
Authors: Okazaki Y , Gotoh E
Published: August 2005

Ti, Zr, Nb, and Ta are biocompatible elements. A Ti-15Zr-4Ta-4Nb alloy for medical implants is being developed. In terms of in vitro cytocompatibility, the new bone tissue response to the Ti-15Zr-4Ta-4Nb alloy determined through rat tibia implantation was equal to or better than that to the Ti-6Al-4V alloy. An acceptable level of biological response can be expected when this alloy is used appropriately because it consists of biocompatible elements and has excellent biocompatibility, corrosion resistance, microstructure, and mechanical and fatigue properties. Therefore, the Ti-15Zr-4Ta-4Nb alloy with a low metal release rate is considered advantageous for long-term surgical implants.
Neutron Flux Effect on the Irradiation Hardening of Type 304 Stainless Steel
Authors: Torimaru T , Kodama M , Tanaka S , Nakamura T , Asano K , Kumagai K
Published: August 2005

In order to investigate the neutron flux effect on the irradiation hardening of type 304 stainless steel, microstructure observation, tensile test, and micro Vickers hardness test were performed on the type 304 stainless steel irradiated to 1.6 × 1024−1.4 × 1026 n/m2 in LWRs, (flux 3.4 × 1015−5.6 × 1017 n/m2/s). The tensile test was carried out in air at 288°C, and the hardness test was also carried out in air, but at room temperature. The amount of irradiation hardening increased with increasing neutron flux. The amount of irradiation hardening was proportional to the 0.25th power of neutron flux. Dislocation loop density increased with increasing neutron flux, and mean diameter had hardly any dependence on neutron flux. From the above, the neutron flux dependence of dislocation loop density could be said to be the main factor controlling irradiation hardening under LWR irradiation conditions. The amount of irradiation hardening of type 304 stainless steel used in LWR is expected to be lower than the predicted amount from higher flux irradiated materials.
A New Low Cost Method For Measuring the Viscoelastic Behavior of Adhesives
Authors: Moonay DJ , McGregor RG , Mastria RA
Published: August 2005

A rotational benchtop Rheometer with vane spindles can be used to measure the static yield stress behavior of materials. By running at different rotational speeds, the Rheometer data can be equated with the viscoelastic information determined by an oscillating rheometer. The rotational Rheometer offers a less expensive method suitable for Quality Control needs.
Method for Quantifying Percentage Wood Failure in Block-Shear Specimens by a Laser Scanning Profilometer
Authors: Scott CT , Hernandez R , Frihart C , Gleisner R , Tice T
Published: August 2005

A new method for quantifying percentage wood failure of an adhesively bonded block-shear specimen has been developed. This method incorporates a laser displacement gage with an automated two-axis positioning system that functions as a highly sensitive profilometer. The failed specimen is continuously scanned across its width to obtain a surface failure profile. The laser is then moved incrementally along the length of the specimen and repeatedly scanned to obtain a three-dimensional digital profile of the surface. This digital profile can then be reconstructed and analyzed with appropriate software. Special algorithms are used to quantify percentage wood failure and degree of wood failure (depth of wood failure) and to recognize various surface anomalies, such as bondline voids. This paper presents exploratory data on several different types of wood failures and correlates these measurements to the visual inspections of skilled evaluators. The device is very sensitive to most observed failures, particularly those with deep wood failure. However, shallow failures close to the bondline can be problematic. The algorithms allow a “roughness” tolerance to be specified to characterize these surfaces. This new method will be useful for automating measurement of wood failure in block-shear specimens with good precision and repeatability.
Determination of Sulfur Content in Crude Oil Using On-Line X-ray Transmission Technology
Authors: Fess S
Published: August 2005

This paper describes the function and use of X-ray Transmission (XRT) analytical instrumentation as applied to the classification and blending of crude oil that contains 0.1–3.3% sulfur by weight. In the XRT method, sulfur absorbs X-rays transmitted between an X-ray source and detector. The technique compensates for density changes in the oil and minimizes the effects of variations in the C/H ratio of the oil. When used on-line the instrument obtains the sulfur measurement in the high-pressure flow conditions required to pump crude oil, typically 800 psig in pipelines. Automatic compensation for variations in oil density and temperature are achieved using integrated densitometer and temperature sensor readings taken by the instrument as the sulfur is being measured. In this paper calibration, precision, and long-term stability results are shown. Experimental data were obtained using a commercially available on-line XRT analyzer.
Measuring Pavement Friction Characteristics at Variable Speeds for Added Safety
Authors: Jackson NM , Choubane B , Holzschuher C , Gokhale S
Published: August 2005

Pavement friction testing is frequently conducted in accordance with the provisions outlined in ASTM E 274, “Standard Test Method for Skid Resistance of Paved Surfaces Using a Full-Scale Tire.” The standard speed of testing in Florida is 40 mph (64.4 km/h). However, due to safety concerns related to testing on high-speed facilities, considerable attention has been focused in recent years on height-sensor based (non-contact) technology. It is potentially well suited for surveying the surface texture characteristics of pavement sections while operating at highway speed.

Although the height-sensor based technology has been available since the 1960s, it continues to mature. A considerable amount of research has been conducted to gain further understanding on the factors affecting high-speed pavement surface surveying from both the analytical and experimental points of view. Still some problems have not fully been resolved, particularly in the interpretation of the measured data and selection of adequate sensing technology (or sensor designs).

The Florida Department of Transportation (FDOT) initiated the present study to assess the feasibility of using high-speed, laser-based sensors to quantify the texture and friction characteristics of asphalt pavements. The main objective of this study is to provide for a safer, faster and more appropriate method of estimating pavement friction characteristics on high-speed facilities, ramps, and at other potentially hazardous sites. Further, it is also intended to provide for a means to obtain a measure of International Friction Index (IFI) in accordance with ASTM E 1960.

This paper presents a description of the FDOT testing program, the data collection effort, as well as the subsequent analyses and findings.
Determination of Beryllium Compounds by NIOSH 7303
Authors: Amer S , Smieja D , Loughrin J , Reichmann L
Published: August 2005

The fourth edition of the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods contains a new, simplified procedure for elemental analysis in workplace atmospheres by Inductively Coupled Argon Plasma Atomic Emission Spectroscopy (ICP-AES) titled NIOSH 7303. This method uses hot block digestion with hydrochloric acid (HCl) and nitric acid (HNO3). The method was presented as fully valid for elemental beryllium. It was further investigated and also found to be valid for beryllium sulfate tetrahydrate and has a recovery efficiency of about 80 % for beryllium oxide. Additionally, no matrix effect on beryllium analysis is apparent by NIOSH 7303 for five common sampling media: polyvinylchloride filters, mixed cellulose ester filters, Whatman® 42 filters, Ghost™ wipes, and Palintest® wipes. Finally, the method has been reevaluated and found to produce a beryllium detection level of 0.0002 μg/mL (0.005 μg/sample for air samples) and a quantifiable level of 0.0005 (0.0125 μg/sample). At this detection limit, the Occupational Safety and Health Administration Permissible Exposure Limit (PEL) of 0.002 mg/m3 can be achieved at the method's detection level with an air sample of 2.5 L or one tenth of the PEL with a sample of 25 L under the prescribed preparation and analytical conditions.
Use of Herbicides to Control the Spread of Aquatic Invasive Plants
Authors: Poovey AG , Getsinger KD
Published: August 2005

Invasive aquatic plants have become problematic in lakes and reservoirs across the United States. Infestations should be aggressively controlled to prevent degradation of water quality, fish and wildlife habitat, and the reduction of biodiversity. Operating under the purview of the US Army Corps of Engineers Aquatic Plant Control Research Program, the Chemical Control and Physiological Processes Team (CCPPT) develops and evaluates environmentally sound strategies for managing invasive aquatic and wetland plants using herbicides. Evaluations are conducted using a multi-tiered approach in customized controlled-environmental chambers, greenhouses, outdoor mesocosms, and pond facilities. The CCPPT employs methods consistent with the herbicide modes of action when conducting herbicide efficacy studies in small-scale experimental systems. Results from these studies are verified in aquatic and wetland field sites throughout the US. Coordination with the US Environmental Protection Agency and state regulatory agencies is undertaken to support the review and registration of new aquatic herbicides and amendments to established labels. Information and technology developed via research efforts are transferred to natural resource managers, the private sector, and the general public.
Which Way Do Concrete Cracks Run?
Authors: Neville A
Published: August 2005

A high stress causes development of cracks, which may fracture aggregate particles or skirt around them. Numerous factors influence the path taken by a crack. No direct studies are available, but the relevant factors are: properties of the parent rock; shape, size, and texture of coarse aggregate particles; properties of the interface and bond; moduli of elasticity of the aggregate and of the matrix; and strength of the matrix relative to the strength of the aggregate. At very early ages, fracture parameters change, but later on, age is not a factor influencing the crack path. The crack path influences the shear strength of beams, in that cracks passing through the aggregate reduce the contribution of aggregate interlock: some aggregates result, therefore, in a low shear strength. This has been found only recently. Establishing experimentally the influences on the crack path would enable us to design mixes economically with balanced properties of strength and ductility.
Biocomposites: Exploring Surface Texture for Cell Adhesion
Authors: Ribeiro R , Asthana P , Ingole S , Shi B , Kuhn T , Liang H
Published: August 2005

This paper discusses the principles behind effects of surface roughness and porosity of materials on cell adhesion, an important question in biocomposites. Literature provided controversial reports of surface roughness effects. We used new evidence to illustrate how cells are attached to polymeric materials.
PolyADP-Ribosylation Is Involved in Neurotrophic Activity
Authors: Visochek Leonid , Steingart Ruth A. , Vulih-Shultzman Ina , Klein Rodica , Priel Esther , Gozes Illana , Cohen-Armon Malka
Published: August 2005

PolyADP-ribosylation is a transient posttranslational modification of proteins, mainly catalyzed by poly(ADP-ribose)polymerase-1 (PARP-1). This highly conserved nuclear protein is activated rapidly in response to DNA nick formation and promotes a fast DNA repair. Here, we examine a possible association between polyADP-ribosylation and the activity of neurotrophins and neuroprotective peptides taking part in life-or-death decisions in mammalian neurons. The presented results indicate an alternative mode of PARP-1 activation in the absence of DNA damage by neurotrophin-induced signaling mechanisms. PARP-1 was activated in rat cerebral cortical neurons briefly exposed to NGF-related nerve growth factors and to the neuroprotective peptides NAP (the peptide NAPVSIPQ, derived from the activity-dependent neuroprotective protein ADNP) and ADNF-9 (the peptide SALLRSIPA, derived from the activity-dependent neurotrophic factor ADNF) In addition, polyADP-ribosylation was involved in the neurotrophic activity of NGF-induced and NAP-induced neurite outgrowth in differentiating pheochromocytoma 12 cells as well as in the neuroprotective activity of NAP in neurons treated with the Alzheimer's disease neurotoxin β-amyloid. A fast loosening of the highly condensed chromatin structure by polyADP-ribosylation of histone H1, which renders DNA accessible to transcription and repair, may underlie the role of polyADP-ribosylation in neurotrophic activity.
Abrupt Maturation of a Spike-Synchronizing Mechanism in Neocortex
Authors: Long Michael A. , Cruikshank Scott J. , Jutras Michael J. , Connors Barry W.
Published: August 2005

Synchronous activity is common in the neocortex, although its significance, mechanisms, and development are poorly understood. Previous work showed that networks of electrically coupled inhibitory interneurons called low-threshold spiking (LTS) cells can fire synchronously when stimulated by metabotropic glutamate receptors. Here we found that the coordinated inhibition emerging from an activated LTS network could induce correlated spiking patterns among neighboring excitatory cells. Synchronous activity among LTS cells was absent at postnatal day 12 (P12) but appeared abruptly over the next few days. The rapid development of the LTS-synchronizing system coincided with the maturation of the inhibitory outputs and intrinsic membrane properties of the neurons. In contrast, the incidence and magnitude of electrical synapses remained constant between P8 and P15. The developmental transformation of LTS interneurons into a synchronous, oscillatory network overlaps with the onset of active somatosensory exploration, suggesting a potential role for this synchronizing system in sensory processing.
Coupled Networks of Parvalbumin-Immunoreactive Interneurons in the Rat Basolateral Amygdala
Authors: Muller Jay F. , Mascagni Franco , McDonald Alexander J.
Published: August 2005

Recent studies indicate that the basolateral amygdala exhibits fast rhythmic oscillations during emotional arousal, but the neuronal mechanisms underlying this activity are not known. Similar oscillations in the cerebral cortex are generated by a network of parvalbumin (PV)-immunoreactive interneurons interconnected by chemical synapses and dendritic gap junctions. The present immunoelectron microscopic study revealed that the basolateral amygdalar nucleus (BLa) contains a network of parvalbumin-immunoreactive (PV+) interneurons interconnected by chemical synapses, dendritic gap junctions, and axonal gap junctions. Twenty percent of synapses onto PV+ neurons were formed by PV+ axon terminals. All of these PV+ synapses were symmetrical. PV+ perikarya exhibited the greatest incidence of PV+ synapses (30%), with lower percentages associated with PV+ dendrites (15%) and spines (25%). These synapses comprised half of all symmetrical synapses formed with PV+ cells. A total of 18 dendrodendritic gap junctions between PV+ neurons were observed, mostly involving secondary and more distal dendrites (0.5-1.0 μm thick). Dendritic gap junctions were often in close proximity to PV+ chemical synapses. Six gap junctions were observed between PV+ axon terminals. In most cases, one or both of these terminals formed synapses with the perikarya of principal neurons. This is the first study to describe dendritic gap junctions interconnecting PV+ interneurons in the basolateral amygdala. It also provides the first documentation of gap junctions between interneuronal axon terminals in the mammalian forebrain. These data provide the anatomical basis for a PV+ network that may play a role in the generation of rhythmic oscillations in the BLa during emotional arousal.
A Comparison of Visceral and Somatic Pain Processing in the Human Brainstem Using Functional Magnetic Resonance Imaging
Authors: Dunckley Paul , Wise Richard G. , Fairhurst Merle , Hobden Peter , Aziz Qasim , Chang Lin , Tracey Irene
Published: August 2005

Evidence from both human and animal studies has demonstrated a key role for brainstem centers in the control of ascending nociceptive input. Nuclei such as the rostral ventromedial medulla and periaqueductal gray (PAG) are able to both inhibit and facilitate the nociceptive response. It has been proposed that altered descending modulation may underlie many of the chronic pain syndromes (both somatic and visceral). We used functional magnetic resonance imaging to image the neural correlates of visceral and somatic pain within the brainstem. Ten healthy subjects were scanned twice at 3 tesla, during which they received matched, moderately painful, electrical stimuli to either the midline lower abdomen or rectum. Significant activation was observed in regions consistent with the PAG, nucleus cuneiformis (NCF), ventral tegmental area/substantia nigra, parabrachial nuclei/nucleus ceruleus, and red nucleus bilaterally to both stimuli. Marked spatial similarities in activation were observed for visceral and somatic pain, although significantly greater activation of the NCF (left NCF,p= 0.02; right NCF,p= 0.01; Student's pairedttest, two-tailed) was observed in the visceral pain group compared with the somatic group. Right PAG activity correlated with anxiety during visceral stimulation (r= 0.74;p< 0.05, Pearson'sr, two-tailed) but not somatic stimulation. We propose that the differences in NCF and right PAG activation observed may represent a greater nocifensive response and greater emotive salience of visceral over somatic pain.
Stargazin Modulates Native AMPA Receptor Functional Properties by Two Distinct Mechanisms
Authors: Turetsky Dorothy , Garringer Eva , Patneau Doris K.
Published: August 2005

AMPA receptors play a central role in basal excitatory synaptic transmission as well as synaptic maturation and plasticity. The transmembrane AMPA receptor regulatory protein (TARP) stargazin (γ2) serves multiple roles in trafficking and stabilizing synaptic AMPA receptors and may be incorporated as an auxiliary subunit. We wanted to determine whether stargazin altered channel function of neuronal AMPA receptors. Transfection of cultured hippocampal neurons with stargazin produced two distinct effects on AMPA receptor functional properties: a sixfold reduction in glutamate-evoked desensitization and a twofold increase in the relative size of responses to the partial agonist kainate. Kinetic and dose-response analyses suggest that the effect of stargazin on glutamate desensitization results from an allosteric interaction that destabilizes the desensitized state of the receptor and that potentiation of kainate responses reflects increased efficacy rather than a change in affinity. These functional effects were also observed in human embryonic kidney 293 cells transfected with various heteromeric and homomeric AMPA receptors, with distinct subunit-dependent effects on glutamate desensitization, kainate efficacy, and trafficking. Two regions of stargazin mediate its functional effects: the C-terminal intracellular domain seems to be more important for effects on glutamate-evoked desensitization and receptor trafficking, whereas the first extracellular domain makes a larger contribution to effects on kainate efficacy. These data indicate that TARPs are involved both in trafficking and direct modulation of channel function and, as auxiliary subunits of neuronal AMPA receptors, must be considered in the functional heterogeneity of neuronal AMPA receptors.
Cholecystokinin Activates Orexin/Hypocretin Neurons through the Cholecystokinin A Receptor
Authors: Tsujino Natsuko , Yamanaka Akihiro , Ichiki Kanako , Muraki Yo , Kilduff Thomas S. , Yagami Ken-ichi , Takahashi Satoru , Goto Katsutoshi , Sakurai Takeshi
Published: August 2005

Orexin A and B are neuropeptides implicated in the regulation of sleep/wakefulness and energy homeostasis. The regulatory mechanism of the activity of orexin neurons is not precisely understood. Using transgenic mice in which orexin neurons specifically express yellow cameleon 2.1, we screened for factors that affect the activity of orexin neurons (a total of 21 peptides and six other factors were examined) and found that a sulfated octapeptide form of cholecystokinin (CCK-8S), neurotensin, oxytocin, and vasopressin activate orexin neurons. The mechanisms that underlie CCK-8S-induced activation of orexin neurons were studied by both calcium imaging and slice patch-clamp recording. CCK-8S induced inward current in the orexin neurons. The CCKAreceptor antagonist lorglumide inhibited CCK-8S-induced activation of orexin neurons, whereas the CCKBreceptor agonists CCK-4 (a tetrapeptide form of cholecystokinin) and nonsulfated CCK-8 had little effect. The CCK-8S-induced increase in intracellular calcium concentration was eliminated by removing extracellular calcium but not by an addition of thapsigargin. Nifedipine, ω-conotoxin, ω-agatoxin, 4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidinium chloride, and SNX-482 had little effect, but La3+, Gd3+, and 2-aminoethoxydiphenylborate inhibited CCK-8S-induced calcium influx. Additionally, the CCK-8S-induced inward current was dramatically enhanced in the calcium-free solution and was inhibited by the cation channel blockerSKF96365, suggesting an involvement of extracellular calcium-sensitive cation channels. CCK-8S did not induce an increase in intracellular calcium concentration when membrane potential was clamped at -60 mV, suggesting that the calcium increase is induced by depolarization. The evidence presented here expands our understanding of the regulation of orexin neurons and the physiological role of CCK in the CNS.
How to Enhance Ipsilateral Actions of Pyramidal Tract Neurons
Authors: Jankowska E. , Cabaj A. , Pettersson L.-G.
Published: August 2005

We have shown previously that ipsilateral pyramidal tract (PT) neurons facilitate the actions of reticulospinal neurons on feline motoneurons (Edgley et al., 2004), which indicates that they might assist the recovery of motor functions after injuries of contralateral corticospinal neurons. Nevertheless, stimulation of ipsilateral PT fibers alone only rarely evoked any synaptic actions in motoneurons. The aim of this study was to investigate possible ways of enhancing such actions and of inducing more effective excitation and inhibition of motoneurons. The effects of stimulation of the ipsilateral PT were investigated after eliminating the spinal actions of contralateral PT fibers by hemisecting the spinal cord at a low thoracic level and were estimated from intracellular records from hindlimb motoneurons. Two measures were used to enhance PT actions. The first was to increase the probability of activation of reticulospinal neurons by mutual facilitation of actions of ipsilateral and contralateral PT neurons. The second was to enhance synaptic transmission between PT neurons and reticulospinal neurons, and in pathways between the reticulospinal neurons and motoneurons via commissural interneurons, by systemic application of a K+channel blocker, 4-aminopyridine (4-AP). The results show that under favorable conditions, ipsilateral PT neurons may induce EPSPs and IPSPs in hindlimb motoneurons, or even action potentials, via the reticulospinal pathway. This study strengthens previous conclusions that ipsilateral PT neurons can potentially replace, at least to some extent, the actions of injured contralateral PT neurons. It also suggests that 4-AP might improve the progress of the recovery.