Filtern
Erscheinungsjahr
Dokumenttyp
Sprache
- Englisch (24)
- Deutsch (9)
- Mehrsprachig (1)
Schlagworte
- Betonbrechsand (2)
- Magnetic domains (2)
- Müllverbrennungsasche (2)
- Nachhaltigkeit (2)
- Passive sampling (2)
- Raman microscopy (2)
- X-ray microdiffraction (2)
- Zünder (2)
- 2D nanomaterial (1)
- 3D printing (1)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (3)
- 8.6 Faseroptische Sensorik (2)
- 1 Analytische Chemie; Referenzmaterialien (1)
- 1.2 Biophotonik (1)
- 4 Material und Umwelt (1)
- 4.3 Schadstofftransfer und Umwelttechnologien (1)
- 6 Materialchemie (1)
- 6.1 Oberflächen- und Dünnschichtanalyse (1)
- 7 Bauwerkssicherheit (1)
- 7.4 Baustofftechnologie (1)
Das Basisanliegen - Einleitung
Mit der zunehmenden Zahl akkreditierter ZfP-Firmen und zunehmender Anwendung risikobasierender Konzepte ergibt sich die Notwendigkeit, internationale Standards wie die DIN EN ISO 17025 und darüber hinausgehende Richtlinien bei der Verfahrensauswahl in der ZfP zu berücksichtigen. Dieser Aufsatz soll aufzeigen, welche internationalen Aktivitäten gegenwärtig für die Zuverlässigkeitsbetrachtungen von Bedeutung sind (siehe auch [1]). In Übereinstimmung mit den Vereinbarungen und Definitionen der European-American Workshops zur Zuverlässigkeit [2, 3] gilt: Das Basisanliegen der Zuverlässigkeitsuntersuchungen beliebiger diagnostischer Systeme besteht darin, den Grad festzustellen mit dem das Prüfsystem in der Lage ist, seinen vorgesehenen Zweck zu erfüllen. Im Falle der ZfP besteht dieser Zweck zumeist in der Aufgabe, Bauteildefekte aufzufinden und zu beschreiben bzw. die Defektfreiheit von Bauteilen zu bestätigen, sowie Wanddicken zu messen oder Material zu charakterisieren.
Das Basisanliegen der Zuverlässigkeitsuntersuchungen findet seinen Niederschlag bei folgenden international relevanten Aktivitäten:
neue ISO 17025 als Notwendigkeit mit variablen Möglichkeiten der Verfahrensvalidierung
als Kettenglied in RBLM (Risk Based Life Time Management) (r) EPERC-Initiative
CEN/TC138/WG9 "Qualifizierung von ZfP-Verfahren"
Six-Sigma Strategie: als notwendiger Bestandteil
ASNT-Initiative: Standing Committee on NDE Reliability: als Arbeitspaket
Produkthaftung: als notwendige Voraussetzung für die Handhabung
During the second European-American Workshop on NDE Reliability, September 99 in Boulder, the term NDE reliability was defined as the degree that an NDT system is capable of achieving its purpose regarding detection, characterization and false calls. The most common but also most expensive - way to determine this degree of capability in e.g. defect detection is to make just a performance demonstration using realistic test samples and to count the correct detections and false calls. For a more efficient way of reliability evaluation we propose to decompose the system into main modules e.g. according to the reliability formula set up on the first workshop: into f(IC) a function of IC the intrinsic capability, determined by the physics and the technique of the NDE method representing an ideal upper bound of the reliability and g(AP) a function of AP the industrial application factor like surface state or limited access to a component in general diminishing the ideal capability and finally h(HF) the function of the human factor which is in general also diminishing the ideal capability. The workshop proposed a rather plain mathematical shape for the formula R = f(IC) g(AP) h(HF) which should be considered merely as a philosophical expression but not as exact mathematical formula to be applied for evaluation of e.g. POD data. We propose to decompose the NDE system into modules in terms of functions of IC, AP and HF if appropriate or additional ones if necessary and then to analyze the mutual relationships of the terms via fault tree analysis. Finally the total reliability of the system is composed of the reliability of the subsystems via the rules of statistical systems theory.
First trials for this approach of data analysis will be presented via examples from NDE systems in the aerospace industry.
Struktur des basischen Zink-O,O'-ethylhexyldithiophosphats in unpolar, aprotischen Lösungsmitteln
(1995)
We compare standard and inverted bulk heterojunction solar cells composed of PCPDTBT:PC70BM
blends. Inverted devices comprising 100 nm thick active layers exhibited short circuit currents of
15 mA/cm², 10% larger than in corresponding standard devices. Modeling of the optical field distribution
in the different device stacks proved that this enhancement originates from an increased absorption of
incident light in the active layer. Internal quantum efficiencies (IQEs) were obtained from the direct
comparison of experimentally derived and modeled currents for different layer thicknesses, yielding IQEs
of ~70% for a layer thickness of 100 nm. Simulations predict a significant increase of the light harvesting
efficiency upon increasing the layer thickness to 270 nm. However, a continuous deterioration of the
photovoltaic properties with layer thickness was measured for both device architectures, attributed to
incomplete charge extraction. On the other hand, our optical modeling suggests that inverted devices
based on PCPDTBT should be able to deliver high power conversion efficiencies (PCEs) of more than
7% provided that recombination losses can be reduced.
We performed spatially resolved synchrotron-induced x-ray fluorescence analyses (SY-XRF) of five silverpoint drawings from the famous `Karlsruhe sketchbook´ and a silverpoint, which is assumed to be an original one used by the Renaissance artist Hans Baldung Grien (1484-1545) himself. The silverpoint, one out of a very small number of ancient styli conserved nowadays, is fixed on the so-called `Karlsruhe sketchbook´. Measurements were executed at the FLUO-TOPO beamline at the electron storage ring ANKA. It has been shown, that SY-XRF at this beamline is nondestructive and sensitive enough for the analysis of minor and major elements in the silver strokes. This study provides new insights into this graphical technique and ancient drawing instruments: results are that three drawings have been created with a common type of silverpoint containing about (10.4 ± 0.7) wt% of Cu. In all the cases, Hg at a 10% level by weight was identified in the strokes. Presence of Hg is not due to the original silver alloy, but is a result of a general alteration phenomenon of silverpoint drawings. This fact is confirmed by the analysis of the original silverpoint, which contains only small traces of Hg. The result for the copper content of the silverpoint (10.4 ± 1.7) wt% is in good agreement with that of these three drawings. It is supposable that the silverpoint found attached today served for the creation of the corresponding drawings. Moreover, the graphical technique of Baldung is found to be continual over three decades. Only one very late drawing dated to 1543 was probably realized with another silverpoint, containing about 3 wt% of Cu. This difference in the chemical composition of drawings from the late period might be used as a more precise dating indicator of Baldung drawings that are not clearly attributed to a certain period.
Zwei Verfahren, der Unterwasser-Test und der Plate-Dent-Test, wurden hinsichtlich ihrer Eignung zur indirekten Bestimmung
der Zündstärke von Zündern untersucht. Die Einflüsse verschiedener Sekundärladungsmassen und unterschiedlichen
Hülsenmaterials von Zündern standen hierbei im Vordergrund.
Der Unterwasser-Test, bei dem als Maß für die Zündstärke die Stoß- und Blasenenergie eines Zünders ermittelt werden,
erwies sich als probate und genaue Bestimmungsmethode. Zünder mit unterschiedlichen Sekundärladungsmassen waren
eindeutig differenzierbar. Das Hülsenmaterial hatte nur einen vernachlässigbaren Einfluss auf die Ergebnisse.
Der Plate-Dent-Test, bei dem die Abmaße des gebildeten Kraters zur indirekten Bestimmung der Zündstärke herangezogen
werden, zeigte gegenteilige Effekte. Ab einem Ladungslänge-Durchmesser-Verhältnis von größer zwei war eine Differenzierung
von Zündern verschiedener Sekundärladungsmasse nicht mehr möglich. Außerdem hatte das Hülsenmaterial
einen signifikanten Einfluss auf die Kraterbildung. Der Plate-Dent-Test ist somit nur für den direkten Vergleich der Zündstärken
baugleicher Zünder z. B. unter variierenden Umweltbedingungen geeignet.---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Two procedures – the underwater test and the plate-dent-test – were examined concerning their applicability for the indirect
determination of the initiating capability of detonators. At this the focus was on the influence of varying explosive masses
and different shell material.
At the underwater test the initiating capability is determined indirectly by measurement and calculation of the shock and
bubble energy. This method proved to be effective and accurate. Detonators with different secondary charge masses could
be distinguished clearly and the shell material had only a negligible influence on the energy release.
The plate-dent-test, at which the dimensions of the formed dent are an indirect measure for the initiating capability, showed
the contrary effects. A differentiation of detonators was proved to be impossible when a relation of charge length to diameter
greater than two was reached. Furthermore, it could be shown that the shell material had significant influence on the
dent formation. Therefore, the plate-dent-test is only suitable for the direct comparison of identical detonators, e. g. under
varying environmental conditions.
Rainfall-triggered runoff is a major driver of pesticide input in streams. Only few studies have examined the suitability of passive sampling to quantify such episodic exposures. In this study, we used Empore-TM styrene-divinylbenzene reverse phase sulfonated disks (SDB disks) and event-driven water samples (EDS) to assess exposure to 15 fungicides and 4 insecticides in 17 streams in a German vineyard area during 4 rainfall events. We also conducted a microcosm experiment to determine the SDB-disk sampling rates and provide a free-software solution to derive sampling rates under time-variable exposure. Sampling rates ranged from 0.26 to 0.77 L d-1 and time-weighted average (TWA) concentrations from 0.05 to 2.11 µg/L. The 2 sampling systems were in good agreement and EDS exceeded TWA concentrations on average by a factor of 3. Our study demonstrates that passive sampling is suitable to quantify episodic exposures from polar organic pesticides.
Magnetic domains have been the subject of much scientific investigation since their theoretical existence was first postulated by P.-E. Weiss over a century ago. Up to now, the three-dimensional (3D) domain structure of bulk magnets has never been observed owing to the lack of appropriate experimental methods. Domain analysis in bulk matter thus remains one of the most challenging tasks in research on magnetic materials. All current domain observation methods are limited to studying surface domains or thin magnetic films. As the properties of magnetic materials are strongly affected by their domain structure, the development of a technique capable of investigating the shape, size and distribution of individual domains in three dimensions is of great importance. Here, we show that the novel technique of Talbot-Lau neutron tomography with inverted geometry enables direct imaging of the 3D network of magnetic domains within the bulk of FeSi crystals.
This overview article provides insight into how to apply Raman spectroscopy in combination with a confocal, optical microscope setup on polycrystalline material systems, in order to obtain quantitative information on phase distribution, grain sizes, crystal orientations and microstrain. Although the present work uses Cu(In,Ga)(S,Se)₂ absorber layers in corresponding thin-film solar cells as a model system to demonstrate the capabilities of Raman microspectroscopy, the approaches discussed may be applied to any organic or inorganic, polycrystalline materials system.
This paper gives a brief overview on3D imaging of magnetic domains with shearing grating neutron tomography. We investigated the three-dimensional distribution of magnetic domain walls in the bulk of a wedge-shaped FeSi single crystal. The width of the magnetic domains wasanalyzed at different locations within the crystal. Magnetic domains close to the tip of the wedge are much smaller than in the bulk. Furthermore, the three-dimensional shape of individual domains wasinvestigated. We discuss prospects and limitations of the applied measurement technique.
More than 5 million non-electric detonators are used annually in Germany for blasting operations. The relative usage of non-electric detonators amounts to about 50% of all civil blasting operations in Germany. BAM, as the notified body for explosives in Germany, tests non-electric detonators for the purpose of EU-type approval under the civil explosives directive, but also in the context of general investigations, e.g. when misfiring occurs. BAM has all facilities to test these detonators according to the European standard EN 13763. The presentation will cover the test facilities of BAM and address some issues of delay time accuracy. Several advantages and disadvantages of the non-electric ignition system will be discussed in the context of case investigations, and conclusions for mining operations and the advoidance of misfiring will be drawn.