bluuebunny/crossref_metadata_2025 huggingface dataset:
Rab6 interacts with the mint3 adaptor protein
Authors: Teber Iskender , Nagano Fumiko , Kremerskothen Joachim , Bilbilis Konstantinos , Goud Bruno , Barnekow Angelika
Published: August 2005

The Rab6 GTPase regulates a retrograde transport route connecting endosomes and the endoplasmic reticulum (ER) via the Golgi apparatus. Recently it was shown that active (GTP-loaded) Rab6A regulates intracellular processing of the amyloid precursor protein (APP). To characterize the role of Rab6A in APP trafficking and to identify effector proteins of the active Rab6A protein, we screened a human placenta cDNA library using the yeast two-hybrid system. We isolated an interacting cDNA clone encoding part of the adaptor protein mint3. The interaction between Rab6A and mint3 is GTP-dependent and requires the complete phosphotyrosine-binding (PTB) domain of the mint protein, which also mediates the association with APP. By confocal microscopy we show that Rab6A, mint3 and APP co-localize at Golgi membranes in HeLa cells. Density gradient centrifugation of cytosolic extracts confirms a common distribution of these three proteins. Our data suggest that mint3 links Rab6A to APP traffic.
Surface lignin and extractives on hardwood RDH kraft pulp chemically characterized by ToF-SIMS
Authors: Kleen Marjatta
Published: August 2005

The chemical characteristics of lignin and extractives on the outermost surface of hardwood rapid displacement heating (RDH) kraft pulp were studied using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Changes in these surface compounds induced by totally chlorine-free (TCF) bleaching were also revealed. The results suggest that the surface lignin remaining on unbleached RDH pulp was remnant from native wood lignin, which was never released from wood fibers, but had undergone structural changes during kraft cooking. Less than half of the surface lignin was removed during bleaching, with the oxygen stage and the final peroxide stage being the most effective. The main wood extractives on the hardwood RDH kraft pulp surface were sterols and steryl esters. TCF bleaching strongly reduced their abundance. Bleaching also removed fatty acids, but less effectively than neutral extractives. Fatty acid sodium salts were partly removed during TCF bleaching, in contrast to fatty acid calcium salts, which were very stable. ToF-SIMS has the unique capability to give valuable chemical information about the complex mixture of compounds on the pulp surfaces. Thus, it complements other surface-sensitive analytical techniques such as electron spectroscopy for chemical analysis (ESCA), atomic force microscopy (AFM) and field-emission scanning electron microscopy (FE-SEM). ToF-SIMS can give detailed chemical information about the effects of process conditions on pulp surface characteristics.
NMR studies on Fraser fir Abies fraseri (Pursh) Poir. lignins
Authors: Balakshin Mikhail Yu. , Capanema Ewellyn A. , Goldfarb Barry , Frampton John , Kadla John F.
Published: August 2005

The composition of mature, juvenile uninfested and juvenile infested Fraser fir wood (Rotholz) and the structures of lignins isolated from these woods were elucidated to verify differences between juvenile and mature wood and the effect of balsam woolly adelgid (BWA) infestation. Milled wood lignin (MWL) isolated from mature, juvenile and Rotholz wood were comprehensively characterized using heteronuclear multiple quantum coherence (HMQC) and quantitative 13C NMR techniques. The Rotholz wood was found to have ∼13% higher lignin content and more than five-fold the amount of galactans than that of the uninfested wood. Rotholz lignin possesses higher amounts of p-hydroxyphenyl units and aliphatic OH groups and a lower amount of alkyl-O-alkyl linkages and dibenzodioxocin moieties. The degree of condensation of the Rotholz lignin was rather similar to that of normal wood. Only small differences in the structure of mature and juvenile wood components were found.
The effect of chlorophorin and its derivative on melanin biosynthesis
Authors: Arung Enos Tangke , Yoshikawa Keisuke , Shimizu Kuniyoshi , Kondo Ryuichiro
Published: August 2005

By means of bioassay-guided fractionation using mushroom tyrosinase, a geranylated stilbene, chlorophorin, was characterized as the principal tyrosinase inhibitor in the heartwood of Chlorophora excelsa (Moraceae). It inhibited the oxidation of L-tyrosine and DL-3,4-dihydroxyphenylalanine (DL-DOPA) due to mushroom tyrosinase and melanin biosynthesis on B16 melanoma cells. Chlorophorin, which is a slight yellowish compound, has previously been reported as an unstable compound in light. On the basis of this finding, a chlorophorin derivative [4-(3″,7″-dimethyloctyl)-2′,3,4′,5-tetrahydroxydihydrostilbene; hexahydrochlorophorin] which is colorless, obtained by the hydrogenation of chlorophorin with Pd/C, was also tested to develop a superior material for practical use. Hexahydrochlorophorin showed more potent inhibitory activity on tyrosinase and melanin biosynthesis, and lower cytotoxicity towards B16 melanoma cells than chlorophorin.
Assessment of continuous distribution of wood properties from a low number of samples: Application to the variability of modulus of elasticity between trees and within a tree
Authors: Baillères Henri , Vitrac Olivier , Ramananantoandro Tahiana
Published: August 2005

The aim of this study was to propose an alternative non-deterministic and non-parametric technique for describing continuous variation in modulus of elasticity (E) within and between stems. The material studied consisted of hybridEucalyptus(Eucalyptus urophylla×Eucalyptus grandis) stems felled at the age of 59 months. Samples for measuringEwere taken along a diameter slab at 1.30 m above ground. The results showed that the proposed reconstruction technique is consistent compared to results from other studies onEucalyptus.Eincreases from pith to bark, following a polynomial distribution. Local and tree-averagedEincreased with cambial age, following a sigmoidal profile that can be described with five characteristic parameters (Eat pith,Eat inflection point,Eafter inflection point, cambial age when latency period ends, and cambial age at inflection point). The tree contributes little to the total variation. The most important changes inEvalue were found with increasing radial position, with this effect eight-fold more important than the tree effect.
Combined shear and compression analysis using a modified Iosipescu shear test device. Experimental studies on dry wood
Authors: Magistris Federica De , Salmén Lennart
Published: August 2005

The mechanical treatment of wood in a refiner involves a complex combination of shear and compression forces. To obtain more knowledge on this process, the possibility of using an apparatus based on the Iosipescu shear test device to measure the behaviour of wood under a combined shear and compression load was tested. In this new apparatus, different combinations of shear and compression load were achieved by different rotations of the shear test device itself. Numerical simulations of the combined shear and compression test were carried out and compared with experimental data to verify the reliability of the modified device as applied to wood. It was concluded that the new apparatus is suitable for applying different combinations of shear and compression load in testing wood samples. However, finite element analysis showed that with the use of homogeneous material in the model, the level of strain reached would be 10-fold smaller. This fact is probably due to the honeycomb structure of the wood cells, which allows for different local deformation that could not be represented by the continuous material used in the model.
An approach to viscoelastic behaviour analysis of wood-based panels by an inverse method of characterisation
Authors: Bos Frédéric , Le Magorou Laurent , Rouger Frédéric
Published: August 2005

The main objective of this paper is to propose an alternative method for viscoelastic characterisation of wood-based panels. Our approach, based on inverse identification methods, allows simultaneous estimation of the whole bending/torsion stiffness matrix of orthotropic plates. Elastic or viscoelastic characterisations are carried out according to the same protocol. The first step consists of optimisation of the experimental set-up, i.e., determination of the best localisation and intensity of the applied stresses and of the best position for boundary conditions. This step is realised for each type of panel using generic algorithms to obtain sensitivities satisfying the test for each stiffness matrix component. An identification procedure is then performed using a finite element program. The measurement of the whole displacement field (500×500 mm2) is made using an optical system. Validation of the elastic identification is carried out by comparison with the mechanical properties obtained from a vibrating test and a simulation tool. Non-conventional analysis of the viscoelastic behaviour of wood-based panels is illustrated for two particular plywood panels.
The mechanosorptive effect in Pinus radiata D. Don.
Authors: Entwistle Kenneth M.
Published: August 2005

Measurements are reported of the mechanosorptive strain in Pinus radiata specimens stressed either in torsion or in bending. It is demonstrated that, to secure valid data, correction must be made for the moisture-induced distortion at zero load. A series of measurements can be made on a single specimen if two successive mechano-sorptive loading cycles are used and the sense of the stress is reversed for the second cycle. At the end of this procedure the specimen has reverted to its original dimensions. The mechanosorptive strain is shown to vary linearly with the applied stress; the ratio of the mechanosorptive strain to the initial elastic strain is therefore an appropriate way of quantifying the mechanosorptive effect. Analysis of torsion and bending data reveals that there is a strong correlation between the magnitude of the mechanosorptive strain and the shear stress component of the applied stress along the cellulose microfibril direction. It is suggested that the mechanosorptive effect arises from the effect of stress on the distribution of hydrogen bonds in hemicelluloses. A detailed model must await more information about the molecular structure of hemicelluloses in the cell walls.
Rate and extent of adsorption of ACQ preservative components in wood
Authors: Tascioglu Cihat , Cooper Paul , Ung Tony
Published: August 2005

The adsorption of copper, [as Cu(II)], monoethanolamine (MEA) and didecyldimethyl ammonium chloride (DDAC) components of CuMEA and alkaline copper quaternary (ACQ) solutions impregnated into wood was followed by measuring the changes in solution concentrations in the wood over time. The rate and extent of copper and MEA adsorption were highly dependent on the solution strength and the conditioning temperature. Both copper and MEA were adsorbed by the wood structure with a rapid initial reaction, with higher relative amounts sorbed from lower concentration solutions. This was followed by a slower adsorption that still had not equilibrated after 7 weeks at 22°C. Generally, the adsorption pattern was similar for copper and MEA, suggesting that they were adsorbed as a copper MEA complex, with an MEA/copper molar ratio close to the theoretical maximum of 4. At a higher conditioning temperature of 50°C the reaction time was greatly reduced, with the adsorption after 1 week higher than after 7 weeks at 22°C, suggesting faster and more complete reaction at higher temperatures. DDAC was adsorbed more quickly and to a higher degree than Cu(II) for all treatment solutions and should be preferentially removed from such solutions, especially if empty-cell treatments are used. There appeared to be higher Cu adsorption from the higher concentration solutions of CuMEA than from corresponding ACQ solutions, likely due to DDAC competition with copper for the same reaction sites.
Prediction of long-term leaching potential of preservative-treated wood by diffusion modeling
Authors: Waldron Levi , Cooper Paul A. , Ung Tony Y.
Published: August 2005

An approach to modeling leaching and leaching impacts of preservative components from treated wood is presented based on three simple laboratory determinations: the amount of preservative component available for leaching (Le), equilibrium dissociation of preservative into free water in wood (Di) and diffusion coefficients for component leaching in different wood directions (D). In this study, the following inorganic wood preservative systems were investigated: chromated copper arsenate (CCA), the copper component of copper azole (CA) and alkaline copper quaternary (ACQ), and boron in disodium octaborate tetrahydrate (DOT). Aggressive leaching of finely ground wood showed that amounts of preservative compounds available for leaching were highest for borates, followed by copper in copper amine systems and arsenic in CCA, copper in CCA and chromium in CCA. The equilibrium dissociation or solubility of components in free water in the wood was much higher for borates and copper amine, followed by copper and arsenic in CCA and chromium in CCA. Use of the applicable diffusion coefficient (D) and Di or Le values in a diffusion model allows the prediction of total amount leached and emission or flux rate at different times of exposure for products with different dimensions and geometries. The approach was tested and generally validated through application of the model to results of laboratory water spray leaching of full-size lumber samples. The approach explains the rapid leaching of boron compounds (large diffusion coefficient and high initial dissociated concentration) compared to other preservative components and predicts that ACQ will have higher initial leaching rates compared to CCA and CA, but the latter preservatives will continue to leach copper at a measurable rate for a much longer time. The practical implications and limitations of the approach are discussed.
An Attempt to Predict a Risk of Some of the Knee Region Ski Injuries by Means of Computer Simulations
Authors: Kietlinski K , Rzymkowski C
Published: August 2005

The thesis presented tries to explain some aspects of the phenomenon of ski injuries and also shows the mechanisms through which there is high risk of soft tissue injury. Based on studies about possible injury mechanisms to the soft tissues of the knee joint, two common knee injuries were selected to be studied: “Two-skier impact” and “Boot Induced Anterior Drawer.” A multi-body skier model with flexible elements equipped with a FEM model of the knee joint was developed for the presented work. The solutions obtained confirmed by a majority that for the previously listed mechanisms a high risk of cruciate ligaments injury occurs, especially for the ACL. No damage to the collateral ligaments, the MCL and the LCL, was noticed in any of the cases considered.
The Effect of Load Reduction Scheme on Crack Closure in the Near-Threshold Regime
Authors: Daniewicz SR
Published: August 2005

Three-dimensional elastic-plastic finite element analyses were conducted to model fatigue crack growth in an M(T) specimen. Variable amplitude loading with a continual load reduction was used to simulate the load history associated with fatigue crack growth threshold measurement. Load reductions with both constant load ratio R and constant maximum stress intensity Kmax were used.

Results indicated that load reduction with constant R generated a plastic wake such that remote crack opening occurred during loading, with the crack front opening prior to a region remote to the crack front. The last region to open was located at the point at which the load reduction originally began, and at the free surface. In contrast, for load reduction with constant Kmax, the crack front was the last to open. The results also indicated the crack opening process is three-dimensional in nature, with regions in the interior opening prior to regions near the free surface.
Ultrasonic Fatigue Testing of Ti-6Al-4V
Authors: Morrissey RJ , Golden PJ
Published: August 2005

The objective of this research was to investigate the high cycle fatigue behavior of a titanium alloy using an ultrasonic fatigue system. Fatigue testing up to one billion cycles under fully reversed loading conditions was performed to determine the ultra-high cycle fatigue behavior of Ti-6Al-4V. Endurance limit results were compared to similar data generated on conventional servohydraulic test systems and electromagnetic shaker systems to determine if there are any frequency effects. In addition, specimens were tested with and without cooling air to determine the effects of temperature on the fatigue behavior. Results indicate that the fatigue strength determined from ultrasonic testing was consistent with conventional testing. However, preliminary results indicate that cooling air may increase the fatigue limit stress at very long lives.
Evaluating Thermal Protective Performance Testing
Authors: Keltner NR
Published: August 2005

Even as better materials are developed for protective clothing, NFPA data indicate the number of burn related fire fighter deaths and severe injuries is increasing. These injuries are unexpected for the most part. As a result, questions arise about Thermal Protective Performance (TPP) ratings and whether performance changes are due to use or the effects of aging. As part of a NIST-sponsored Small Business Innovative Research project, current TPP test techniques were evaluated. Some changes and extensions are suggested.

In TPP tests, dry fabric samples or ensembles are exposed to heat flux of 83 kW/m2 with nominally 50% radiative and 50% convective heat transfer. Heat transmission through the test sample is measured with a copper calorimeter. The TPP Rating is the time in seconds required for a 2nd degree burn.

Current problems include:

1) Current test methods overestimate time to 2nd degree burn.

2) No information is provided on maximum potential burn damage.

3) No information is provided on heat transfer or fabric properties.

4) No information is provided on how performance changes with use.

Suggested changes and extensions include:

1) Change the heat source — use a modified radiant protective performance technique.

2) Replace the copper calorimeter with a thermal skin simulant sensor.

3) Estimate burn damage using a two step analysis method.

4) Obtain both dry and damp thermal properties for modeling clothing performance.
Progress in the Characterization of the Cutting Resistance of Protective Materials
Authors: Vu TBN , Vu-Khanh T , Lara J
Published: August 2005

A sliding sharp edge that penetrates a material is one of the most dangerous cases of cutting because it requires the smallest applied normal load. This study aims to analyze the cutting mechanics and mechanism of protective rubber materials in the presence of friction and the effect of the material's mechanical behavior and the blade's sliding velocity on the material's cut resistance. The International Standard ISO 13997 cut test method, which consists of measuring the distance that a straight blade slides horizontally to cut through a material under a constant applied normal force, was used to investigate the cutting phenomena. In practice, the cut resistance of a material is given by the contribution of the material's intrinsic strength and the frictional distribution between the material and the blade that slides and penetrates it. This study demonstrates that two types of friction are involved in material cutting: a macroscopic friction induced by the gripping of the material and by the applied normal load on the two sides of the blade; and a sliding friction associated with cut-through of the material that occurs along the face of the blade tip. For rubber materials, commonly used in protective gloves, the adhesion force due to the gripping of the material on the blade edge could be several times greater than the friction due to the applied normal force. Thus, the cutting energy required to break the molecular chains in rubber materials is much smaller than the energy dissipated by friction. For these materials, the elastic modulus, the structure of the material, as well as the sliding velocity, have a significant effect on the friction. Therefore, all of these properties can affect the cutting resistance results. A better understanding of the cutting mechanism in protective materials is a fundamental step in developing better performing protective materials.
Improved Formulations through Synergistic Combinations Based on Alkyl Glucosides
Authors: Bergström K , Johansson IM
Published: August 2005

Sugar surfactants have attracted a lot of interest in the last decades, both due to technical properties as well as to the extremely favorable ecological and toxicological properties. It is well known that alcohol glucosides have excellent aqueous solubility, a low temperature dependence compared to nonionic ethoxylates, and are stable in the presence of high levels of electrolytes. Furthermore, they are compatible with anionic, cationic, and other nonionic surfactants, making them extremely suitable for formulating concentrated products in the agrochemical area. In this paper, the synergistic effect of short-chained alkyl glucosides mixed with alcohol ethoxylates or amine derivatives have been investigated. These synergies have been manifested by lowering both surface tension and cmc as well as increasing wetting properties towards hydrophobic surfaces. The model system used contained agrochemical electrolytes such as glyphosate, MCPA-DMA salt and fertilizers. The relevance of the finding is supported by the increased bio-efficacy of a mixed adjuvant seen in a greenhouse test. Furthermore, this study shows that short-chained glucosides can be used as efficient solubilizers for adjuvants or wetting agents in high electrolyte system (i.e., fertilizers, active ingredients) to avoid phase separation. The effect has been assessed by studying the influence on cloud point as well as the amount of glucoside needed to solubilizer a nonionic wetting agent into a high electrolyte solution.
Predicting Oxidation and Deuterium Ingress for Zr-2.5Nb CANDU Pressure Tubes
Authors: Bahurmuz AA , Muir IJ , Urbanic VF
Published: August 2005

The pressure boundary of a CANDU® fuel channel is composed of a cold-worked Zr-2.5Nb pressure tube, which has each end rolled into a stainless-steel end fitting. Heavy-water (D2O) coolant (250–310°C) flows over and through twelve or thirteen fuel bundles contained in each pressure tube. During operation, some deuterium generated by aqueous corrosion of the tube surface enters the metal. Additional deuterium also enters through the rolled joint between the tube and the end fitting.

Predictive models for deuterium ingress are required for fitness-for-service assessments for operating pressure tubes and for the development of new reactor designs. A predictive model for assessing the long-term oxidation of, and deuterium ingress into, the body of the pressure tubes has been developed from in-reactor tests of samples which had been pre-oxidized to obtain oxide thickness values representative of long-term behavior. Deuterium ingress is modeled based on a fraction (2–10 %) of the corrosion-freed deuterium entering the metal. The current version of the model contains relationships describing the oxidation rate as a function of oxide thickness, temperature, concentration of dissolved oxygen in the water, and fast neutron flux and fluence. It can successfully predict the observed deuterium-uptake history of pressure tubes in existing CANDU reactors. The model projects a slight increase in the rate of oxidation and deuterium ingress over time. This increase is much less than for Zircaloy-2, a material used in early CANDU units.

In parallel with model development, there are experimental programs involving detailed surface analysis of removed pressure tubes and irradiation tests focused on elucidating the mechanisms of oxidation and deuterium ingress. As the results of these programs become available, they will be incorporated into the predictive model. This presentation will focus on the model and recent results from the supporting experimental programs.
Modeling the Effects of Oversize Solute Additions on Radiation-Induced Segregation in Austenitic Stainless Steels
Authors: Hackett MJ , Was GS , Simonen EP
Published: August 2005

Oversize solute additions to stainless steels hold promise for reducing radiation-induced segregation (RIS), possibly delaying the onset and severity of irradiation-assisted stress-corrosion cracking (IASCC). The Modified Inverse Kirkendall (MIK) model for RIS in austenitic stainless steels was adapted to include the effects of defect trapping, which is expected to be caused by oversized solutes, on RIS. The model accounts for the sensitivity of RIS to both dose rate and temperature. Model results show that the primary contribution to the reduction in RIS occurs through vacancy trapping and recombination with migrating interstitials, requiring strong solute binding energies on the order of 1.0 eV. The maximum reduction in RIS due to defect trapping increases with dose rate and temperature. The general trends of the model are consistent with experimental data from proton and neutron irradiations.
Ductility of Zircaloy-4 Fuel Cladding and Guide Tubes at High Fluences
Authors: Yagnik SK , Hermann A , Kuo R-C
Published: August 2005

Zircaloy fuel cladding suffers progressive degradation of ductility as its neutron exposure and hydrogen uptake increase with burnup. The loss of ductility appears to be the key property governing the cladding integrity in service. We report ductility data of Zircaloy-4 fabricated in stress-relief annealed (SRA) and recrystallized (RXA) conditions, covering a range of fluence, hydrogen content, and irradiation and test temperature.

The testing was performed on unirradiated and irradiated Zircaloy-4 cladding and guide tubes in SRA and RXA conditions, respectively, in the temperature range 25–350°C. These materials had been exposed to an estimated neutron fluence of ∼8 to 10 × 1025 n/m2 (E > 1 MeV) over four cycles of PWR operation. Due to its RXA fabrication condition, the guide tube material was also believed to represent BWR cladding. The hydrogen contents in the irradiated cladding was in the range of ∼200–600 ppm, exhibiting typical radial distribution of circumferential hydrides. By comparison, the hydrogen content in the irradiated guide tube material was in the range of ∼250–1800 ppm, exhibiting fairly uniform through-wall distribution of circumferential hydrides. Tensile tests and hydraulic burst tests were conducted on 130–150 mm long tubular specimens. In addition, smaller specimens machined in the form of 55 mm long curvilinear dog-bone and 10 mm slotted semicircular arc were tested in plane stress and plane strain configurations. Corresponding unirradiated archive materials in as-received condition and with uniform hydrogen charging up to 1200 ppm were also tested by identical methods. In all tests the fracture mode was examined by SEM fractography.

The investigations revealed a decrease in ductility of Zircaloy-4, mainly caused by irradiation and only partly by increasing hydrogen content. Unlike the elongation data, the strength data remained nearly constant with increasing hydrogen content in both materials at all test temperatures. The irradiated RXA material showed better ductility than irradiated SRA material at equivalent hydrogen levels, and exhibited a clearer correlation of ductility with hydrogen content, mainly due to its uniform hydrogen distribution. The paper will provide these and other quantitative data, e.g., those correlating ductility with the local (near fracture surface) hydrogen content. The paper synthesizes the experimental results and discusses their possible application to the criteria for hydrogen concentration and ductility limits in high burnup fuel.
Recent Surveillance Data and a Revised Embrittlement Correlation
Authors: Server WL , Lott RG , Rosinski ST , English CA
Published: August 2005

The mechanistically-guided embrittlement correlation model adopted in ASTM E 900-02 was based on U.S. surveillance results current through calendar year 1998. There now exists an extensive amount of new surveillance data that includes a large amount of boiling water reactor (BWR) results from a supplemental surveillance program designed to augment the plant-specific BWR surveillance programs. These recent data allow a statistical check of the ASTM E 900-02 embrittlement correlation, as well as the NRC correlation model currently being used in the pressurized thermal shock (PTS) re-evaluation effort and the older Regulatory Guide 1.99, Revision 2 correlation. Even though the ASTM E 900-02 embrittlement correlation is a simplified version of the NRC model, a comparison of the two embrittlement correlation models utilizing the new database has proven to be revealing. Based on the new BWR data, both models are inadequate in their ability to predict BWR results. Other aspects of the two models are presented, as well as plans to develop a revised embrittlement correlation.
Stress Intensity Factor Analysis and Fatigue Behavior of a Crack in the Residual Stress Field of Welding
Authors: Terada H
Published: August 2005

This paper deals with the behavior of a crack in the residual stress field induced by butt weld in a wide plate. It is known that the distribution pattern of residual stress is similar regardless of welding process, though the size and the magnitude of the residual stress depend largely on the welding process. Stress intensity factor and stress redistribution induced by the crack extension were calculated for a crack with arbitrary length and location. The stress redistributions caused by crack extension obtained by the present analysis showed good agreement with the experimental data. Fatigue crack propagation behavior in the residual stress field reported by Glinka was also examined from the ΔK point of view. In this paper, the effect of residual stress on the fatigue crack propagation rate is considered to be the effect of varying mean stress. The concept of ΔKeff, where the effect of residual stress is accounted as the correction factor by the way of simple superposition, is shown to predict the crack growth rate with sufficient accuracy.
Certification of Charpy V-Notch Reference Test Pieces at IRMM
Authors: Roebben G , Lamberty A , Pauwels J
Published: August 2005

The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC) of the European Commission (EC) is one of the reference materials producers which certifies reference test pieces for the indirect verification of Charpy pendulum impact machines. The certification approach taken at IRMM consists of two main steps. In a first step, a Master Batch of reference test pieces is certified for each of a number of chosen nominal energy levels (currently 30 J, 60 J, 80 J, 120 J, and 160 J). The certified absorbed energy value of these Master Batches is determined in an international round-robin. In the second step of the certification process, the Master Batch test pieces are used to determine the certified value of Secondary Batches of reference test pieces of the same nominal energy. This is achieved by comparing samples of Master and Secondary Batch under repeatability conditions. In this paper, this Master Batch — Secondary Batch approach is critically assessed in terms of traceability and uncertainty of the certified absorbed energy. It is shown that the produced reference test pieces are fit-for-purpose: they meet the requirements of their intended use (indirect verification).
Understanding Polymeric Pads in Pre-CMP Conditioning
Authors: Ng D , Kulkarni M , Xu G , Severs P , Marvin R , Xiao J , Liang H
Published: August 2005

Experiments were conducted to understand the principles behind polymeric pads during pre-CMP conditioning. Nylon, polycarbonate, and polyurethane pads were tested against copper pins in a slurry containing 3 wt % alumina nanoparticles. The surface properties of pads were estimated after conditioning. The wear of pads along with friction coefficient was evaluated during friction experiments. Results show that contact angles of polycarbonate and polyurethane pads increase with their surface roughness, while those of nylon show the opposite tendency. Surface roughness of pads induced by conditioning could influence the wear performance of nylon and polycarbonate, more than that of the polyurethane pad. Our previous study has shown that the stimulation of friction induces materials transfer during CMP. In this work, we further investigated the effect of such transfer on wear mechanisms of pads during conditioning and polishing. Compared with nylon and polycarbonate, chemical and material properties of polyurethane and their tribological performance are more stable. This makes polyurethane a unique material for CMP.
Advanced Methods of Coating Adhesion Testing
Authors: Gitis NV , Xiao J , Vinogradov M
Published: August 2005

Adhesion of coatings from 1 nm to 0.1 mm was successfully evaluated with multi-sensing technology, based on simultaneous high-resolution force, electrical, and acoustic measurements. Sharp changes in the signals were indicative of the thresholds of adhesion and delamination for various thin and thick coatings during scratching and indenting with several test tools, both sharp (diamond tips) and dull (balls).
Fracture Mechanics Applied to Adhesive Joints
Authors: Wheeler GE , Madsen BS , DeVries KL
Published: August 2005

Since the advent of synthetic adhesives in the middle of the last century, the growth in their usage has been so phenomenal that a handbook, the International Plastics Selector-Adhesives, published by D.A.T.A. in 1991, lists some 5000 different adhesive formulations that are commercially available. Despite their wide usage, much is not well understood about adhesives and adhesive joint failure. A few observations relevant to this discussion of Fracture Mechanics Analysis of Adhesive Joints are: (a) The stress distribution in such joints is never as simple as often assumed, and the usually reported “standard test results” often completely ignore the most important aspects of the stress distribution. (b) Crack growth does not always initiate at the point of maximum stresses in an adhesive joint. (c) The locus of adhesive crack growth is often somewhat removed from the adhesive-substrate bond-line, but there are instances where it closely follows this bond-line. (d) Adhesive Fracture Mechanics analysis can provide significant information on the resolution of questions raised in these observations. This presentation will review some of the work in these areas by graduate students in our laboratory. Some of the cited work was accomplished by previous lab students. Other parts of the cited work are from ongoing research by current students. The presentation will endeavor to demonstrate that: (a) Adhesive Fracture Mechanics can be used to quantitatively predict the strength of adhesive joints and, more particularly, to elucidate the effects of such factors as adherend thickness, adhesive thickness (and variation), amount of overlap, geometric configuration, material discontinuities, etc. (b) Other factors being equal, crack growth tends to initiate at locations of maximum energy release rate irrespective of whether or not these are points of maximum stresses. (c) The preferred locus of crack growth is along those paths for which the energy release rate is a maximum. In each of these cases, results of a fracture mechanics analysis will be presented along with experimental verification of the analyses.
Advances in ICP-MS Technologies for Characterization and Ultra-Trace Speciation as a Tool for the Petroleum Industry
Authors: Paszek J , Mason KJ , Mennito AS , McElroy FC
Published: August 2005

Particular elements can, even at trace levels, impact product quality, deposit formation, and regulatory compliance. Characterization of trace and ultra-trace level constituents in aqueous and/or organic matrices has often required the need to employ more than one analytical technique. In recent years, improvements in ICP-MS technologies have made it a preferred technique for multi-element trace level characterization in a variety of matrices. Coupling ICP-MS with various liquid chromatography techniques has enabled a unique capability to speciate organo-metallics at ppb levels. This paper will show how ICP-MS has been successfully used to measure ppb levels in refinery effluent streams. It will demonstrate how hyphenated ICP-MS techniques assisted in development of bioremediation options for selenium removal in wastewater treatment plants.
Direct Trace and Ultra-Trace Metals Determination in Crude Oil and Fractions by Inductively Coupled Plasma Mass Spectrometry
Authors: Dreyfus S , Pécheyran C , Magnier C , Prinzhofer A , Lienemann CP , Donard OFX
Published: August 2005

A method was developed to analyze direct trace and ultra-trace metal elements in crude oil and its fractions (maltenes-asphaltenes) by ICP-MS after sample dilution in xylene. Efficient introduction of organic compounds requires addition of O2 for complete combustion of the sample, carbon deposit on cones (interface) and extraction lenses was minimized by optimization of argon to oxygen ratio in the plasma. A PFA-100 (100 μl.mn−1) MicroFlow Nebulizer and a Scott “double pass” chilled spray chamber were associated for an optimal introduction of petroleum products. The Q-ICP/MS was equipped with platinum cones to limit drifts caused by cone corrosion during an organic analysis. A standard addition method was realized for the calibration procedure in order to control the matrix effects. Method validation was completed by analyzing three certified reference materials from the National Institute for Standards and Technology (NIST). NIST 1085b, NIST 1084a, and NIST 1634c accuracies were approximately 10 %. Detection limit of ultra trace elements in xylene were at pg.g−1 level. A clean PFA filter system was developed to separate the oil fractions (maltenes and asphaltenes) by precipitation of asphaltenes (heavy fraction) in n-heptane. For optimal detection conditions, the samples were diluted in xylene according to their pre-estimated element concentration range. Total mass balance shows a recovery close to 100 % for Ni, V, Cu, Mo, Ag, Sn, Ba, and Pb. These results show that elements analyzed are highly concentrated in the asphaltenic fraction.
Latest Improvements on Using Polarized X-Ray Excitation EDXRF for the Analysis of Low Sulfur Content in Automotive Fuel
Authors: Wissmann D
Published: August 2005

Polarized X-Ray EDXRF has been used for the analysis of low levels of a broad range of elements in light matrices for a long time. By using the polarization of the excitation radiation, the background scattered by the sample is drastically reduced. For the analysis of low sulfur in automotive fuels, this meant a detection limit comparable to the WDXRF technique.

Recent developments in detector technology and in closed coupled static geometry result in further improvement of sensitivity for this application.

This paper shows the development of this technique for the analysis of low sulfur content in petroleum products. It shows the results of a round robin test, performed by CEN TC 19 WG 27 in 2001.

The technical basis of these data is compared to the recent technical developments, and future options are shown. The influence by sample preparation and sample presentation, which might be special for this analytical technique, is investigated and discussed.
Fuel Analysis by Filter Furnace Electrothermal Atomic Absorption Spectrometry
Authors: Tittarelli P , Priola M , Ricchiuto S , Katskov DA , Ngobeni P
Published: August 2005

The determination of Mn, Fe, Co, and Zn was performed in gasoline, jet, and diesel fuel samples by electrothermal atomic absorption spectrometry using the Transverse Heated Filter Atomizer (THFA). Thermal conditions were experimentally defined for the investigated elements.

The elements were analyzed without the addition of chemical modifiers, using organometallic standards for the calibration. Gasoline samples were analyzed directly, while jet and diesel fuel samples were diluted 1+3 with n-heptane.

The following LODs were obtained using 40 µL injections: 0.08 µg/L Mn, 0.35 µg/L Fe, 0.54 µg/L Co, and 0.06 µg/L Zn. The limits of determination, calculated for diesel and jet fuel samples, were 1.2 µg/kg Mn, 4.9 µg/kg Fe, 7.6 µg/kg Co, and 0.8 µg/kg Zn. The corresponding limits of quantitation for gasoline samples were about four times higher.
Generalized Archie's Law for Estimation of Soil Electrical Conductivity
Authors: Shah PH , Singh DN
Published: August 2005

Archie's law, which is an empirical relationship between the electrical conductivity of rocks and their porosity, has been used widely for saturated rocks, while Archie's second law has been developed for unsaturated rocks. Both of these laws assume that the rock matrix is non-conducting and the conduction takes place through the pore-solution only. However, not many efforts have been made by the researchers to check suitability and applicability of Archie's law to the saturated or unsaturated states of the soils. Hence, a generalized Archie's law for soils, by incorporating their physical properties, volumetric moisture content, and bulk and pore-solution conductivities, was attempted in this study utilizing the data available in the literature. Further, to demonstrate the validity of this law, four soils with entirely different properties were used. These soils were characterized by conducting conventional laboratory tests, and their bulk and pore-solution conductivities were determined with the help of an impedance analyzer and a pressure membrane extractor.
Determination of Total Mercury in Crude Oil by Combustion Cold Vapor Atomic Absorption Spectrometry (CVAAS)
Authors: Fox BS , Mason KJ , McElroy FC
Published: August 2005

Unlike many heavy metals, mercury is a long-range air and water pollutant whose load on the environment is increasing. According to published reports, a major source of atmospheric mercury is the burning of coal for electrical power generation. However, certain crude oils may contain up to several hundred ng/g of total mercury. Accurate analysis of total mercury in crude oil is the first step in determining the value of a crude oil and one's ability to process the material within the refinery, while generating finished products. This paper details the use of Combustion Cold Vapor Atomic Absorption Spectrometry (CVAAS) technology for the analysis of crude samples and distillation cuts. The instrument described in the report is one of several instrument methods currently being evaluated by groups in industry and government. The use of a boat-inlet sample introduction system allows crude oil and other types of material to be analyzed without acid digestion. The strengths and weaknesses of the combustion-CVAAS technique, along with a year's worth of operating experience, will be presented from the user's perspective.
Interlaboratory Evaluation of a Portable Fluorescence Method for the Measurement of Trace Beryllium in the Workplace
Authors: Ashley K , McCleskey TM , Brisson MJ , Goodyear G , Cronin J , Agrawal A
Published: August 2005

Researchers at Los Alamos National Laboratory (LANL) developed a field-portable fluorescence method for the measurement of trace beryllium in workplace samples such as surface dust and air filters. The technology has been privately licensed and is commercially available. In cooperation with the Analytical Subcommittee of the Beryllium Health and Safety Committee, we have carried out a collaborative interlaboratory evaluation of the LANL field-portable fluorescence method. The interlaboratory study was conducted for the purpose of providing performance data that can be used to support standard methods. Mixed cellulose ester (MCE) membrane filters and Whatman 541 filters were spiked with beryllium standard solutions so that the filters spanned the range ≈0.05 − ≈0.5 µg Be per sample. Sets of these filters were then coded (to ensure blind analysis) and sent to participating laboratories, where they were analyzed. Analysis consisted of the following steps: 1. Removal of the filters from transport cassettes and placement of them into 15-mL centrifuge tubes; 2. mechanically-assisted extraction of the filters in 5 mL of 1% ammonium bifluoride solution (aqueous) for 30 min; 3.–4. filtration and transfer of sample extract aliquots (100 µL) into fluorescence cuvettes; 5. introduction of 1.9 mL of detection solution (to effect reaction of the fluorescence reagent with beryllium in the extracted sample); and 6. measurement of fluorescence at ≈475 nm using a portable fluorometer. This work presents performance data in support of a procedure that is targeted for publication as a National Institute for Occupational Safety and Health (NIOSH) method and as an ASTM International standard.
Dynamic Modelling and Simulation of Squirrel-Cage Asynchronous Machine with Non-Linear Effects
Authors: Okoro OI
Published: August 2005

The paper presents the dynamic modelling and computer simulation of a squirrel-cage induction machine with non-linear effects. The computer simulation for the transient operation is obtained from the non-linear differential system of equations, which describe the induction machine in the rotor reference frame and with currents as state variables. It is shown that by using the characteristic data available from d.c. measurement, no-load, Blocked rotor, and retardation tests of the machine as well as the results obtained from the optimization of the T-model rotor circuit, accurate simulation of the machine under dynamic condition is possible. The simulated time function of the transient current, mechanical speed, and shaft torque characteristics of the machine are compared with the experimental results.
The Mechanical Characterization of Low Work Hardening, High Strength Steel
Authors: Scott RI , Hodgson PD
Published: August 2005

One of the major challenges in assessing the mechanical properties of recovery annealed steel is the strain localization that occurs almost immediately on the formation of the first Lüders band, such that no or limited propagation of the Lüders band occurs along the tensile coupon. The stress raiser associated with the geometry of the standard tensile coupon means that this plastic deformation is often completely outside the standard extensometers on the coupon. Hence, no strain is measured during the test. While this is not important for assessing the tensile strength of the steel, it does mean that the strain related properties, such as the elastic limit of the steel, cannot be measured using standard testing techniques.

This work addresses this issue by examining three techniques for ensuring that the strain occurs inside the extensometer. It is shown that the best technique is the extended extensometer, where the gauge length covers slightly more than the tensile coupon parallel length. While this leads to some variation in the width of the material being measured, compensation can be made by adjusting the strain to correct the Young's Modulus.

This technique has direct implications not just for recovery annealed steels, but for other high strength, low work hardening materials such as ultrafine ferrite. A particular requirement of these high strength steels in structural applications is a high elastic limit; hence, measurement of the strain related properties for these high strength materials must be considered vital in their mechanical assessment.
Modifizierte Optimale Regelung – Stabilitätsorientierter nichtlinearer Reglerentwurf (Modified Optimal Control – Stability-Oriented Nonlinear Control)
Authors: Sackmann Martin
Published: August 2005

In diesem Beitrag wird mit dem Konzept der Modifizierten Optimalen Regelung auf das erste stabilitätsorientierte Reglersyntheseverfahren im Zustandsraum für nichtlineare zeitkontinuierliche Mehrgrößensysteme eingegangen, das robuste Stabilität, Optimalität und günstiges dynamisches Verhalten konstruktiv miteinander kombiniert. Die Leistungsfähigkeit und die Vorteile der Methodik werden beim Reglerentwurf für das nichtlineare Modell 6. Ordnung einer Raumfähre dargestellt.