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Eingeladener Vortrag
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NDT of Concrete Structures
(2002)
Communication: Fire retardant coatings are deposited on polyamide-66 using plasma polymerisation. Chemical composition and thickness of deposits are adjusted varying the plasma treatment based on hexamethydisiloxane mixed with oxygen. The fire retardancy performances are evaluated using a cone calorimeter. The correlation between fire retardancy and thickness as well as chemical composition is discussed.
Characterization of bond performance of textiles in cement matrices using fiber optic sensors
(2002)
Laboratory model test for monitoring the new main railway station of Berlin - The Lehrter Bahnhof
(2002)
The isoelectric point is a material property for the characterization of acid-base behavior of the powder surface. The IEP of two alumina powders (AKP-30, Grade A) with different particle size characteristics in aqueous suspension has been determined by colloid vibration current (CVI) and particle charge detection (PCD) methods in moderately concentrated suspensions in order to qualify these methods for a future standardization. The solid loading of the suspensions were 1 and 5 vol%. The comparison of the IEP determined by PCD and CVI was in good agreement. However, the solid loading dependence of IEP and a large IEP hysteresis (at 1 vol%) were observed, which do not allow a proper determination of the IEP. The recording of the potential curve and therfore the determination of the IEP with CVI was difficult for the suspension of Grade A powder due to formation of agglomerates at pH values near the pHIEP.
Zeta potential as measured with the electrokinetic sonic amplitude (ESA) method has been compared to streaming potential as measured with the particle charge detection (PCD) method. The measurements have been carried out on identical suspensions of a-Al2O3, SiC and Si3N4 with a solids volume fraction of 1% and 10%. Zeta potential and streaming potential are related by a linear function. The correlation coefficients for this relationship are better than 0.99 for the suspensions with 1% solids loading. For the suspensions with 10% solids loading, correlation coefficients are slightly lower due to the influence of increasing viscosity. Regardless of lower correlation at the higher solids loading, the isoelectric pH is constant within the limits of accuracy of the pH measurements.
VDI/VDE-Guideline 5570 - The First Comprehensive Standard on Characterization and Testing of POF
(2002)
Several colour-difference formulas such as CMC, CIE94, and CIEDE2000 have been developed by modifying CIELAB. These formulas give much better fits for experimental data based on small colour differences than does CIELAB. None of these has an associated uniform colour space (UCS). The need for a UCS is demonstrated by the widespread use of the a*b* diagram despite the lack of uniformity. This article describes the development of formulas, with the same basic structure as the DIN99 formula, that predict the experimental data sets better than do the CMC and CIE94 colour-difference formulas and only slightly worse than CIEDE2000 (which was optimized on the experimental data). However, these formulas all have an associated UCS. The spaces are similar in form to L*a*b*. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 282-290, 2002; Published online in Wiley InterScience (www.interscience.wiley.com).
Introduction
Due to the long history of railroad companies around the world, varying means of examination according to the specifications for the different railroad components have been carried out based on the general industrial progress of the country [1-3]. For more than 50 years the application of customized ultrasonic techniques for the examination of railroad components has increased, in comparison to conventional ultrasonic techniques used until to the end of 20th century. In this traditional atmosphere some accidents have disturbed the silent harmony of companies involved in the production of critical parts. More than ever high speed modern trains require modern and advanced examination techniques [4-8]. For practical application new ultrasonic techniques have been developed and optimized in co-operation with the German Railroad Company. In the present contribution the inspection of railroad axles will be described. The ultrasonic technique used for the examination is the phased array technique. The optimization of the phased array probes for the different geometries of the axles given was completed using a computer model for directivity calculations. In relation to the limited accessibility between wheel and brake angles of incidence for shear waves in the range between 28° and 72° are necessary.
During the examination of the axles a a considerable amount of ultrasonic data must be stored (storage of the digitized A-scans). However, due to economic aspects the evaluation of this data should be carried out in a very short time. The whole examination of one axle should not exceed 5 minutes. Therefore we have developed a special evaluation program adapted to the particular problematic of the axle inspection. The build up of the whole inspection system was done with partners from the industry like Krautkramer and a division of the Research Department of the Deutsche Bahn AG. In this consortium the Research Department of the Deutsche Bahn AG was responsible for the specification of the inspection problem, Krautkramer for the organization of the whole technical follow up and BAM for the development and optimization of the ultrasonic inspection technique as well as for the evaluation software. Some examples concerning the optimization process will be described in the present contribution.
Results of an interlaboratory comparison of XPS data obtained with stainless steel are presented. Only one photoelectron spectrometer model was used. The stainless-steel sample surfaces were analysed in different states by XPS: as received, after sputtering to I(C 1s)/I(Fe 2p3/2) 0.025 and after removing a chromium-enriched oxide layer following a certain protocol. The Fe, Cr and Ni elemental concentrations were evaluated from the respective XPS data submitted by the participants of the interlaboratory test experiment. Total means, repeat standard deviations (sr) and reproducibility standard deviations (sR) are presented. The best reproducibility standard deviations were obtained for the XPS analysis after removal of a chromium-enriched oxide layer and quantification of the XPS intensities without taking the contamination elements of carbon and oxygen into account. The absolute reproducibility standard deviation of the elemental concentrations in that case is as small as 1.1-1.5 at.%. This gives 2%, 6% and 16% for the relative reproducibility standard deviation of the concentrations of iron, chromium and nickel, respectively. The total means of the iron, chromium and nickel concentrations finally obtained agree within 2sR with bulk values determined by wavelength-dispersive x-ray fluorescence spectroscopy. Comparison to an earlier interlaboratory test experiment shows that using only one model of photoelectron spectrometer reduces the reproducibility standard deviations efficiently. Copyright © 2002 John Wiley & Sons, Ltd.
The feasibility of performing SI-traceable carbon isotope amount ratio measurements following conversion of carbon into CF4 was studied. A procedure for the direct fluorination of carbon with elemental fluorine was developed, and the conversion step was checked for losses, blank contributions, and the absence of systematic isotope effects. Gas chromatography was used to identify and quantify the gaseous fluorination products and to isolate CF4 from byproducts. After fluorination of graphite carbon, CF4 and perfluoroalkanes with up to six carbon atoms were observed as reaction products. Within an uncertainty of 10%, the graphite carbon was fully recovered in the gaseous carbon fluorides, with the main product being CF4 (80-90%) and C2F6 as the major byproduct. The fluorination and GC procedures were found to introduce an alteration not bigger than 0.03 ± 0.04 on the isotopic composition of CF4. Carbon blank contributions introduced during the fluorination procedure were below 0.5% relative to a typical sample of 4 mg of carbon. For two of the materials investigated, the carbon isotope ratios measured on a differential mass spectrometer were reproducible within a standard deviation of ~0.1 for several individual fluorinations. For these materials, the developed fluorination procedure is a straightforward process, which can be used as a foundation to establish SI-traceable measurements of carbon isotope amount ratios. However, for the third graphite material the formation of byproducts (C2F6-C6F14) was found to induce significant isotopic fractionation.
Prestressing steels can be exposed in prestressed concrete structures in construction stage (ungrouted duct) to environmental conditions causing formation and growth of hydrogen induced cracks with brittle fracture of the steel. The risk of this hydrogen induced stress corrosion cracking can be minimized by appropriate treatment, but there is a requirement for construction to approve only prestressing steel having no enhanced susceptibility to stress corrosion cracking. The paper describes the historical development of the different test methods proposed in the past and gives an overview on the general requirements for a suitable test method to assess the hydrogen-induced stress corrosion susceptibility of prestressing steels.
Since 1982, based on investigations on construction sites and transfer of the results into laboratory tests, a test method is available enabling realistic estimation of suitable application possibilities of prestressing steels. This so called DIBt-test is approved to distinguish between prestressing steels susceptible to hydrogen induced stress corrosion cracking and those suitable and therefore approvable steels at practical environmental conditions. Furthermore the test enables estimation of corrosion risk for newly developed prestressing steels with higher strength.
Translated Abstract
Beurteilung der Prüfverfahren zur Untersuchung der Spannungsrisskorrosionsempfindlichkeit von Spannstählen
Spannstähle können in Spannbetonbauwerken im Bauzustand (unverpresstes Hüllrohr) Umgebungsbedingungen ausgesetzt sein, die zur Bildung und Ausbreitung wasserstoffinduzierter Risse mit Sprödbruch des Stahles führen können. Das Risiko dieser wasserstoffinduzierten Spannungsrisskorrosion kann einerseits durch eine sachgemäße Verarbeitung der Spannstähle minimiert werden, andererseits besteht die Notwendigkeit nur solche Spannstähle für die Baupraxis zuzulassen, die unter baupraktischen Bedingungen keine erhöhte Empfindlichkeit für Spannungsrisskorrosion besitzen. Die vorliegende Arbeit beschreibt die historische Entwicklung der verschiedenen vorgeschlagenen Prüfverfahren und gibt einen Überblick über die allgemeinen Anforderungen an ein geeignetes Verfahren zur Beurteilung der wasserstoffinduzierten Spannungsrisskorrosionsempfindlichkeit von Spannstählen.
Seit 1982 steht, begründet durch Untersuchungen auf Baustellen und Umsetzung der Ergebnisse in Laborversuchen, ein Prüfverfahren zur Verfügung, das eine wesentlich realistischere Einschätzung der Einsatzmöglichkeiten von Spannstählen zulässt. Dieser sog. DIBt-Test hat sich bewährt, um unter praktischen Umgebungsbedingungen gegen H-induzierte Spannungsrisskorrosion empfindliche Spannstähle von geeigneten und damit zulassungswürdigen Stählen zu unterscheiden. Des weiteren erlaubt die Prüfung ebenfalls eine Abschätzung des Korrosionsrisikos für neuentwickelte, höherfeste Spannstähle.
Nowadays, micro-x-ray fluorescence analysis has become an established tool for the non-destructive investigation of art objects. However, as these types of sample often forms complex and inhomogeneous layer systems, the quantitative evaluation of the measurements is far from a standard routine. In this paper a fingerprint model is described, which we developed to discriminate between different iron-gall inks of historical manuscripts or compositions. Fundamental parameter methods are used to take self-attenuation, interference from the paper background and diffusion of the ink into the paper into account. The capability of the method to contribute to the solution of archaeometric problems is exemplified by the investigation of an ancient composition. Finally, the restrictions of the model and possible improvements are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Apparently that the type testing procedure should be conducted under the conditions ensuring reproducibility of its outcomes. We investigated various factors effecting upon the reproducibility. To obtain quantitative characteristics of indications visibility the image-processing hard-and software were used. It was established that there are two main groups of these factors. The first depends on the differences between various test panels, which are used for type testing. The second one concerns the reproducibility of some stages of penetrant testing procedure (excess penetrant removing and developer application). The recommendations to increase the reproducibility of type testing are developed and illustrated experimentally.
The determination of penetrant system sensitivity as a part of type testing should be conducted ensuring reproducibility of the result. We investigated some factors effecting the reproducibility. To obtain quantitative characteristics of indications visibility, an image processing system was used [1]. We used 3 different sets of reference blocks (rb1, rb2, rb3) corresponding to type 1 of EN ISO 3452-3 [2]. Two fluorescent penetrants with different sensitivities and the same wet solvent developer were used.
It was established that the reproducibility of type testing is influenced by mainly two principal factors. First there are the differences between reference blocks. Second one concerns the reproducibility of penetrant testing procedure, especially excess penetrant removal and developer application.
According to EN ISO 3452-3 a reference block for determination of sensitivity level of fluorescent penetrants consists of a set of three nickel-chrome plated panels with 10, 20 and 30 µm plating thickness. Transverse cracks are made in each panel by stretching the panels in the longitudinal direction and width to depth ratio of the cracks should be approximately 1/20. Each panel presents a certain sensitivity level, which is characterised by the level of visibility of the indication. The highest level 3 corresponds to the panel with 10 µm thickness plating. Each panel is cut longitudinally (perpendicular to the crack) so that 2 sheets (panels A and B) with nearly the same cracks will be produced. These panels A and B of a reference block are used for relative evaluation, for example to compare sensitivities of two penetrants. It is considered that the application of the same penetrant to both panels with subsequent adequate development results in the same visibility of the indications on these panels.
Quantitative correlations between the abilities of the reference blocks used for determining of the sensitivity were obtained in our investigations. We used the relations between the measured values of light-fluxes from the indications of similar comparing areas on two panels. These indications correspond to certain cracks parts of the same total length on both comparing areas. The relations of the steps between the panel are responsible for the definition of the sensitivity groups. From our investigations it follows that the steps of the different sets are different. Besides it was established that the indications visibility for the same penetrant applied on different reference blocks might have a considerable difference depending on the penetrant sensitivity: the higher penetrant sensitivity, the smaller is such a difference between the steps 30/20 and 20/10. For example, for rb3 the relations 30/20 and 20/10 for lower sensitive penetrant (I1) reached factor 3 comparing with factor 2 for higher sensitive penetrant (I2).
Some results of the comparison between the 3 sets (rb1, rb2, rb3) investigations are summarised in Table 1 with rb1 as a reference.
Model for inhomogeneous ink paper layer systems measured with micro X-ray fluorescence analysis
(2002)
Multiple pulse investigations of 130-fs Ti:sapphire laser-induced damage of a high reflecting mirror consisting of alternating ?/4-layers of Ta2O5 and SiO2 and a single 500-nm Ta2O5 film were performed. In both cases, fused silica served as the substrate. For a fixed number of 1000 laser pulses per spot, a decrease in the damage threshold fluence of the mirror by a factor of two was observed by changing the repetition rate from 10 Hz to 1 kHz. A single 500-nm Ta2O5 film shows higher damage resistance compared to the mirror. The mirror and the Ta2O5 film samples were partially coated with a 300-nm-thick aluminium layer. The aluminium coating does not influence the damage threshold of the dielectrics underneath.
XTEM and TFXRD investigations of ohmic Ti/Al/Ti/Au/WSiN contacts on AlGaN/GaN HFET layer systems
(2002)
The microstructural features of the high-temperature-stable ohmic contact system Ti/Al/Ti/Au/WSiN on AlGaN/GaN were investigated using analytical transmission electron microscopy and thin film x-ray diffraction. For two typical rapid thermal annealing steps at 750 °C (non-ohmic behaviour) and 850 °C (ohmic behaviour) the intermetallic phases at the metal-semiconductor interface are presented. Increased annealing leads to the transformation of an Al2Au-AlAuTi phase mixture to a mixture of Al2Au-Al3Au8 phases and the formation of Ti-Al-nitride layers at the interfaces. In light of these results the electrical contact properties are discussed.
The device output of ISO/IEC-test chart files which include colours defined in the CIELAB colour space and the
corresponding device dependent colour spaces shows a lot of problems. The correponding colours produce very
different output or no output difference on monitors and printers. Sometimes for the present standard software
the monitor output is very different and there are no output differences on printers or vice versa. If a PostScript
MTL code (Measurement, Transfer and Linearization) is added to the code of an ISO/IEC-test chart (the NP file)
then the output of the new FP file produces the same output as expected by users and CIE colorimetry if CIELAB
colours and related device dependent colours are used for input. For this intended output property the definition of
the Colour Workflow (CW) and the Output Linearization (OL) is included in all ISO/IEC-test charts of the FP form.
- Remark: The output of this paper produces large color differences (often 20 CIELAB) for the NP files on most
printers and monitors. The large colour differences for corresponding colours of different colour spaces are not
intended by users and CIE colorimetry. The output of the FP files produces no colour differences as intended.
An attempt was undertaken to obtain a better understanding of the tribological properties of two wear-resistant coatings on tool steel by structural and microchemical analysis of wear particles using a transmission electron microscope. Coatings were deposited by physical vapor deposition and plasma-assisted chemical vapor deposition techniques and tribological properties were derived from reciprocating sliding tests of the coatings against alumina balls. Three types of wear particles were identified by electron diffraction and energy dispersive X-ray spectroscopy: nanocrystalline rutile (TiO2), nanocrystalline graphite and microcrystalline graphite. Low coefficients of friction, of the order of 0.2, were attributed to the formation of solid lubricant films of sub-stoichiometric TiO2-x Magnéli phases and/or graphite.
Corresponding colours of the olv* and cmy0* colour spaces (described by the PS image operators "4 colorimage, 3
colorimage and image" and described by the PS vector graphic operators "setcmykcolor, setrgbcolor and setgray")
show in a lot of cases an equal output as required by users and colorimetry. For many software - hardware combinations
the colours defined in the olv* and cmy0* colour spaces appear very different (about 15 CIELAB) in the
output. An example is the software Adobe Reader which produces a brownish output on the monitor for the greys
defined in the cmy0* colour space compared to the achromatic output for greys defined in the olv* colour space.
An ISO/IEC-test chart file uses the 6 different PS operators on one page. This test chart is used for a system test
(combinations of hardware and software) of the device colour output. For this test the 16 step colour scales of Fig.
B4 and D4 of the ISO/IEC-test chart according to ISO/IEC 15775 are used. If unexpected result occur then there are
methods to correct the output. e. g. by the MTL code (Measurement, Transfer and Linearisation).
A local, global or external transfer is used to make the output of raw scan olv*' image data of slide and negative film
very similar. A large variation of exposure has no influence on the output. For slide film this exposure range is
between about -0,5 stops (under exposure) and +1,0 stops (over exposure). For negative film the exposure range is
between about -1,0 stops (under exposure) and +3,0 stops (over exposure). The output appears the same for a local
and external transfer. All the different exposures of two film materials are shown on one page. The global transfer is
applied to an image of the flower motif (Fig. B1 and D1 of ISO/IEC-test chart according to ISO/IEC 15775).
Development of wood-inorganic composites with enhanced properties and environmental stability
(2002)
The special importance of the analysis of non-metals in high purity metals, which will serve as national standards for elemental analysis in Germany, is illustrated for oxygen and nitrogen. The typical range of the mass fraction of oxygen and nitrogen in these materials is below 10.MU.g/g, often close to 1.MU.g/g. The two methods applied at BAM for these measurements are classical carrier gas hot extraction (HE) and carrier gas hot extraction after activation with photons (PAA-HE). The approach, the methods and their advantages and limitations are discussed. Comparative results from the measurement of oxygen and nitrogen in Cu, Fe, Ga, Pb, Sn and W are presented. (author abst.)
Long-term performance of permeable reactive barriers has been investigated in laboratory experiments using elemental iron and hydroxyapatite as reactive materials and uranium as contaminant. Accelerated testing has been performed by applying elevated pollutant concentration and an increased flow velocity. The spatial distribution of uranium in the test columns has been investigated using a radioactive tracer. The results show that the migration pattern exhibits a linear behaviour.
Composite liners (a geomembrane in intimate contact with a mineral liner) are frequently used to line landfills and contaminated sites. It is therefore very important to characterise the behaviour of these systems even under extreme conditions.
An investigation was undertaken to determine the influence of a mixture of concentrated organic contaminants on composite liner materials taken from test cells that had been dismantled after a 12-year permeation test.
The organic hydrocarbons had permeated the HDPE-geomembrane and had then migrated or had been adsorbed within the mineral liners, depending on their properties. The obtained concentration profiles of the contaminant mixture components indicate that the various mineral layer materials have selective retardation abilities which correspond to the different parameters of the organic compounds as well as of the mineral layer.
In addition, contaminant transport in the composite liners tested was modelled and the results of the model analysis compared with measurement data. An example (acetone) illustrates the calculated spatial and temporal contaminant concentration.
The composite liners investigated exhibit a very good sealing capacity against the concentrated organic contaminants used.
The fabric of mineral liner materials that had been exposed to organic compounds over a 12-year period was investigated as part of a wider research project. Macromorphological and micromorphological changes in the fabric were identified using computed tomography and polarisation microscopy.
Special care was taken to ensure artefact free sampling and sample preparation, in particular, the drying method used, has a substantial influence on the quality of the thin sections.
Fabric changes due to contaminant permeation over several years are, by and large, relatively small and their intensity is material specific. Silty clay CML1, in particular, contains a somewhat greater number of fissures and voids in comparison with the original material. The superposition of various processes in both test procedures and sample preparation may lead to fabric changes which can impede interpretation of the results.
Results of the inter-laboratory comparison "Determination of nanometric step heights with AFM"
(2002)
Non-destructive evaluation of advanced materials by synchrotron radiation refraction topography
(2002)
The 57Fe-Moessbauer spectrum of (dmpipzH2)2[FeIII(H2O)2Cl4][FeIII Cl4]Cl2 (1) consists of two doublets caused by a strongly distorted octahedral and a non-distorted tetrahedral component. Both (dmpipzH2)[FeIIIBr4]2 (2) and (trienH2)[FeIIIBr4]Br (3) show only one doublet indicating a more strongly distorted iron(III) species for 2 and a less-distorted one in the case of 3. For all compounds investigated, the ESR spectra reveal the existence of ground states with predominant antiferromagnetic coupling. The Néel temperatures amount to <4.2 K for 1, 4 K for 3 and 48 K for 2. In the case of 2, both the Moessbauer and the ESR spectra reveal the formation of exchange-coupled {FeBr4} units which has been attributed to a significant cation influence. The fine structure of residual paramagnetic [FeBr4]- subunits remaining in the crystalline matrix could be directly determined. Temperature dependent AC and DC susceptibility measurements of 2 and 3 confirmed the results.
Raman spectroscopic and 35Cl-NMR scans of Hydro-Xan®, a preparation containing the biocatalytically effective Tetrachlorinedecaoxide anion (TCDO), are described. The spectroscopic analyses showed that HydroXan® does not contain chlorite initially used in the preparation anymore. Furthermore, a structure of four equal chlorate-like ClO3-groups was indicated for TCDO by the scans. Such a structure is supported by the long-term stability of HydroXan® found at tests over 267 days.
The flame retardant effect of zinc sulphide (ZnS) in plasticised poly(vinyl chloride) (PVC-P) materials was investigated. PVC-P containing different combinations of additives such as 5% ZnS, 5% of antimony oxide (Sb2O3) and 5% of mixtures based on Sb2O3 and ZnS were compared. The thermal degradation and the combustion behaviour were studied using thermogravimetry (TG), coupled with FTIR (TG-FTIR) or with mass spectroscopy (TG-MS), and a cone calorimeter, respectively. A detailed and unambiguous understanding of the decomposition and release of the pyrolysis products was obtained using both TG-MS and TG-FTIR. The influence of ZnS, Sb2O3 and the corresponding mixtures on the thermal decomposition of PVC-P was demonstrated. Synergism was observed for the combination of the two additives. The combustion behaviour (time to ignition, heat release, smoke production, mass loss, CO production) was monitored versus external heat fluxes between 30 and 75 kW m-2 with the cone calorimeter. Adding 5% of ZnS has no significant influence on the fire behaviour of PVC-P materials beyond a dilution effect, whereas Sb2O3 works as an effective fire retardant. Synergism of ZnS and Sb2O3 allows the possibility of replacing half of Sb2O3 by ZnS to reach equivalent fire retardancy.
The thermal degradation and the combustion behavior of glass fiber-reinforced PA 66 materials containing red phosphorus were investigated. Thermogravimetry (TG), TG coupled with FTIR, and TG coupled with mass spectroscopy were used to investigate the thermal decomposition. The flame retardant red phosphorus was investigated with respect to the decomposition kinetics and the release of volatile products. The combustion behavior was characterized using a cone calorimeter. Fire risks and fire hazards were monitored versus external heat fluxes between 30 and 75 kW/m2. Red phosphorus acts in the solid phase and its efficiency depends on the external heat flux. The use of red phosphorus results in an increased amount of residue and in a corresponding decrease in total heat release. The decrease of the mass loss rate peak results in a corresponding decrease of the peak heat release. With increasing external heat flux applied the first effect on the total heat release decreases linearly, whereas the second effect on the peak heat release expands linearly. The investigation provides insight into the mechanisms of how the fire retardant PA 66 is achieved by red phosphorus controlling the degradation kinetics. Taking into account that a decrease of the volatile products also leads to a decrease of heat production in the flame zone and that the char acts as heat transfer barrier, a reduced pyrolysis temperature is suggested as a further feedback effect.
A consortium has recently been initiated to study the macroscopic and microscopic properties of basaltic and andesitic rocks as analogue materials for Mars. The goal of this project is the integration of diverse spectroscopic approaches to
evaluate the composition and texture of Mars materials using both in situ and remote sensing techniques. Initial emphasis is placed on assessment of the mineral composition for low albedo areas (basalt vs andesite vs weathering) of the Martian surface through spectral analysis of a suite of samples that have been exceptionally well characterized in the laboratory. The initial results indicate that the visible/NIR reflectance spectra, mid-IR reflectance and emission spectra, and Mössbauer spectra contain consistent diagnostic features associated with the measured modal mineralogy and provide baseline data for the first group of well characterized basalts. The consortium study involves integrating multiple remote sensing techniques for recent and upcoming missions to Mars in order to compare the results obtained by these instruments and thereby strengthen interpretive results.
A new method has been developed for the measurement of sulfur in gas oils using a high pressure asher (HPA) for sample digestion. This, combined with a calibrated enriched isotopic reference material, and high precision mass spectrometry, makes it a powerful tool for an accurate and precise determination of the sulfur content in fossil fuels. The method described here was one of the methods used in the certification of the candidate reference materials BCR-104R, BCR-671 and BCR-672. Approximately 0.2 g of the gas oil samples were spiked with the spike isotopic reference material IRMM-646, which is enriched in 34S, and combusted in an HPA using nitric acid. The isotopes of sulfur were measured as arsenic monosulfides (AsS+) using a thermal ionization mass spectrometer equipped with a Faraday detector. The total uncertainty of the sulfur content (k = 2) is about 1%. The certified reference materials NIST SRM-2724b and NIST SRM-1619b and BCR-105 were used as part of the method validation work. The mass content of sulfur in BCR-104R was measured to be 1014 µg g-1, BCR-671 has 450 µg g-1 sulfur and BCR-672 shows a sulfur mass content of 201 µg g-1. The sulfur content of the candidate reference materials is homogeneous for the sample size used.
The standard for advanced technical ceramics ENV 843-4 of 1995 (Vickers, Knoop and Rockwell superficial hardness tests) was validated within the framework of the CERANORM EC-project. The paper reports on depth sensing hardness measurements done for comparison with the other hardness tests. The instrumented indentation test is a modern technique (recent issue ISO/DIS 14577) that has the potential to take into account the specific response of materials in a much better way. An evaluation has been made to establish whether the instrumented hardness technique is a appropriate method for advanced technical ceramics and offers potential for additional applications.
In collaboration with the United States Department of Agriculture and a number of major milling companies, the "Insect-Detect" immunoassay for analyzing insect contamination in grains has been compared with three more traditional methods, X-ray analysis, cracking and flotation, and the insect fragment test (IFT). Testing was carried out in blind fashion using clean wheat samples that were spiked with differing numbers of grain kernels infested with late instar larvae of the granary weevil (Sitophilus granarius (L.)). Three different laboratories analyzed the samples for each of the four methods. The collaborative trials showed that the insect immunoassay clearly provided the most accurate measurement of actual insect infestation, followed by X-ray analysis. While both cracking and flotation and IFT procedures provided a general measure of contamination, they showed much greater variability.
The Bundesanstalt für Materialforschung und -prüfung (Federal Institute for Materials Research and Testing) (BAM) is establishing a system of primary reference materials to meet the demands for metrological traceability and to act as national standards in the field of elemental analysis. For all elements of the periodic table - except those that are gases or radioactive - two different kinds of reference materials are being certified. One is for analyte calibration (Type A) and one for problems concerning matrix matching (Type B). These substances are of very high purity and of defined stoichiometry. As far as possible, pure elements and metals rather than pure compounds are used. The certification of both types of material requires most elements of the periodic table to be certified at very low levels using trace element analysis methods. The application of these methods is described and examples of the certification of copper and iron are given.