TY - JOUR A1 - Pech, Anja A1 - Wilke, Olaf A1 - Mull, Birte A1 - Horn, Wolfgang A1 - Jann, Oliver T1 - Development of a TDS-GC-FID method for the determination of methanol and ethanol in air N2 - A method for the determination of very volatile organic compounds (VVOC) in air was developed and successfully tested for methanol and ethanol. Carbotrap300® (a multi-bed tube using Carbopack C®, Carbopack B® and Carbosive SIII®) was selected as sorption material for thermal desorption and tested for its suitability for emission test chamber measurements. The adsorption behaviour and the chromatographic results are influenced negatively by spiking aqueous solutions on the adsorption medium for calibration purposes. The latter effect can be reduced by blowing dry air across the adsorbent to remove the adsorbed water. Detection and quantification limits were determined for a GC-FID system and compared to GC-MS. The applicability of the method was tested with a methanol eliminating silane modified polymeric adhesive (SMP-adhesive for parquet) in an emission test chamber N2 - Eine Methode zur Bestimmung von sehr leicht flüchtigen Verbindungen in Luft wurde für Methanol und Ethanol entwickelt und erfolgreich getestet. Dafür wurde Carbotrap300® (Multibettrohr aus Carbopack C®, Carbopack B® und Carbosive SIII®) als Sorptionsmedium für die Thermodesorption ausgewählt und dessen Eignung für Emissionskammermessungen untersucht. Das Adsorptionsverhalten und die chromatographischen Ergebnisse werden negativ durch die Aufgabe von wässrigen Kalibrierlösungen auf das Adsorptionsmedium beeinflusst. Durch das Überleiten von trockener Luft kann dieser Effekt verringert werden, da so das adsorbierte Wasser entfernt wird. Die Nachweis- und Bestimmungsgrenzen wurden für ein eingesetztes GC- FID-System ermittelt und mit einem GC-MS verglichen. Mit einem methanolabspaltenden silanmodifizierten Polymerklebstoff (SMP-Parkettkleber), der in eine Emissionskammer eingebracht wurde, konnte die Tauglichkeit der Methode überprüft werden. PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-297020 UR - http://www.gefahrstoffe.de/gest/article.php?data[article_id]=76019 SN - 0949-8036 SN - 0039-0771 SN - 1436-4891 VL - 73 IS - 11/12 SP - 477 EP - 482 PB - Springer-VDI-Verlag CY - Düsseldorf AN - OPUS4-29702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weller, Michael G. T1 - Immunoassays and biosensors for the detection of cyanobacterial toxins in water N2 - Algal blooms are a frequent phenomenon in nearly all kinds of fresh water. Global warming and eutrophication by waste water, air pollution and fertilizers seem to lead to an increased frequency of occurrence. Many cyanobacteria produce hazardous and quite persistent toxins, which can contaminate the respective water bodies. This may limit the use of the raw water for many purposes. The purification of the contaminated water might be quite costly, which makes a continuous and large scale treatment economically unfeasible in many cases. Due to the obvious risks of algal toxins, an online or mobile detection method would be highly desirable. Several biosensor systems have been presented in the literature for this purpose. In this review, their mode of operation, performance and general suitability for the intended purpose will be described and critically discussed. Finally, an outlook on current developments and future prospects will be given. KW - Algal toxins KW - Cyanotoxins KW - Biotoxins KW - Blue-green algae KW - Harmful algal blooms KW - Microcystins KW - Nodularins KW - Anatoxin-a KW - Anatoxin-a(s) KW - Cylindrospermopsin KW - Saxitoxins PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-294728 DO - https://doi.org/10.3390/s131115085 SN - 1424-8220 VL - 13 IS - 11 SP - 15085 EP - 15112 PB - MDPI CY - Basel AN - OPUS4-29472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ziegler, Mathias A1 - Myrach, Philipp A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Laser-Thermografie für die schnelle Prüfung auf mikroskopische Risse in reflektierenden metallischen Oberflächen N2 - Thermografische ZfP-Verfahren erlauben die Erkennung einer Vielzahl von Defekten in unterschiedlichsten Werkstoffen. Neue Ansätze unter Verwendung von Lasern ermöglichen darüber hinaus die Prüfung auf Oberflächenrisse. Wir stellen die neuesten Entwicklungen dieser vielversprechenden Technik vor und zeigen warum deren Einsatz potentiell die Standardprüfverfahren Magnetpulver- bzw. Eindringprüfung für eine Reihe von Prüfproblemen beerben könnte. Hierzu stellen wir die Prüfergebnisse zu unterschiedlichen metallischen Werkstoffen, Rissgrößen und -typen in Abhängigkeit der Prüfparameter vor. Die aktuelle Grenze der Nachweisempfindlichkeit für die mittels klassischer Thermografie schwer prüfbaren hochreflektierenden Metalloberflächen liegt mit Rissbreiten und -tiefen von weni-gen Mikrometern im Bereich der fluoreszierenden Magnetpulver- und Eindringprüfung. Dabei sind weder Verbrauchsmittel noch eine Oberflächenpräparation notwendig und eine Prüfung kann berührungslos und automatisiert über Entfernungen im Meter-Bereich erfolgen. T2 - DGZfP-Jahrestagung 2013 CY - Dresden, Germany DA - 06.05.2013 KW - Thermografie KW - Laser KW - Risse PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-288706 SN - 978-3-940283-49-8 IS - DGZfP-BB 141 (Di.2.A.4) SP - 1 EP - 8 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-28870 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Röllig, Mathias A1 - Steinfurth, Henrik A1 - Ziegler, Mathias T1 - Untersuchung von Hochleistungs-LEDs für den Einsatz in der zerstörungsfreien Prüfung mittels Thermografie N2 - Für die optische Erwärmung von Prüfteiloberflächen sind Blitz- und Halogenlampen Stand der Technik. Der Vorteil dieser Wärmequellen liegt in ihren relativ geringen Anschaffungskosten bei gleichzeitig hohen Leistungsdichten am Prüfobjekt. Nachteilig ist bei den Halogenlampen die Limitierung der möglichen Modulationsffequenz auf ca. 1 Hz für die Anwendung dieser Quelle in der Lockin-Thermografie. Blitzlampen bieten für gewöhnlich nur eine feste Blitzdauer bei einer geringen Taktrate. Beide Anregungsquellen müssen in Reflexionsanordnung mit Filtern betrieben werden um die entstehende thermische Eigenstrahlung als Störquelle zu eliminieren. Wir stellen Untersuchungen an Hochleistungs-LEDs für den Einsatz in der aktiven Thermografie vor. Diese Lichtquellen werden durch die rasante Entwicklung der möglichen Leistungsdichten nun auch für die thermografische ZfP interessant. Sie zeigen ähnlich dem Laser eine schmale und auf den Werkstoff abstimmbare spektrale Verteilung der Strahlungsleistung bei moderaten Kosten. Die zugrunde liegende Elektrolumineszenz generiert kaum Wärmestrahlung und ermöglicht dadurch die Prüfung während des Erwärmungsvorganges ohne größeren Aufwand. Modulationsfrequenzen über 100 Hz mit thermischen Eindringtiefen < 1 mm sind möglich. Dadurch qualifizieren sich die LEDs zur Anwendung in der Lockin-Thermografie von Metallen und zur oberflächennahen Prüfung von Schichtsystemen. Durch die fast verzögerungsffeie Reaktion der LED auf das steuernde Signal sind nahezu beliebige zeitliche Anregungsformen möglich. Mit solch flexiblen Anregungsformen ließen sich bereits bei den photothermischen Verfahren erfolgreich höhere Tiefenreichweiten und -auflösungen gegenüber den klassischen Methoden der monofrequenten Lockin - und energiereichen Kurzimpuls-Anregung erzielen. Untersuchungen dieser Möglichkeiten im praktischen Einsatz der HochleistungsLEDs werden vorgestellt und mit herkömmlichen Lichtquellen verglichen. T2 - Thermographie-Kolloquium 2013 CY - Leinfelden-Echterdingen, Germany DA - 2013-09-26 KW - Thermografie KW - Hochleistungsleuchtdioden KW - Hohe Prüfraten KW - Schnelle Modulationsfrequenzen PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-293975 SN - 978-3-940283-52-8 VL - DGZfP-BB 143 SP - Vortrag 3, 1 EP - 8 AN - OPUS4-29397 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neukammer, J. A1 - Hussels, M. A1 - Kummrow, A. A1 - Devonshire, A. A1 - Foy, C. A1 - Huggett, J. A1 - Parkes, H. A1 - Zel, J. A1 - Milavec, M. A1 - Schimmel, H. A1 - Unger, Wolfgang A1 - Akgoz, M. A1 - McHugh, V. A1 - Grunert, H.-P. A1 - Zeichhardt, H. T1 - Survey results on nucleic acid tests of infectious diseases: present status and need for rapid and patient near diagnostics N2 - This survey will discuss current and emerging isothermal and rapid polymerase chain reaction (PCR) based nucleic acid amplification methods for patient near diagnostics. To assess the clinical need of rapid diagnostics for infectious diseases based on nucleic acid tests (NATs) we performed and analysed a questionnaire among laboratories participating in corresponding INSTAND ring trials for external quality assurance. The questions concerning new amplification technologies like isothermal nucleic acid amplification, potentially suited to significantly decrease turnaround times, were complemented by questions to evaluate the present status of NATs. Besides end-users, companies were also addressed by sending out a manufacturer specific questionnaire. Analysis of the answers from 48 laboratories in 14 European countries revealed that a much shorter turnaround time is requested for selected pathogens compared to about 2 h or longer when applying temperature cycling amplification, i.e. PCR. In this context, most frequently mentioned were MRSA, norovirus, influenza A and B viruses, cytomegalovirus (CMV) as well as hepatitis B virus (HBV) and hepatitis C virus (HCV). At present, 8% of the laboratories having participated in this survey apply isothermal amplification of nucleic acid to identify infectious pathogens. KW - Nucleic acid tests KW - Infectious diseases KW - Virus detection KW - Bacteria detection KW - Isothermal nucleic acid amplification KW - Status report KW - Questionnaire KW - NAT KW - PCR PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:0183-lab0000160 UR - http://www.egms.de/static/en/journals/lab/2015-6/lab000016.shtml DO - https://doi.org/10.3205/lab000016 SN - 1869-4241 VL - 6 SP - 1 EP - 11 PB - GMS CY - Düsseldorf AN - OPUS4-36133 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hothan, Sascha A1 - Häßler, Dustin T1 - Über die Entwicklung von Anwendungsregeln für reaktive Brandschutzsysteme auf Stahlzuggliedern N2 - Der vorliegende Beitrag stellt den Entwicklungsstand von Anwendungsregeln für reaktive Brandschutzsysteme auf Stahlzuggliedern zusammenfassend dar. Dabei wird insbesondere auf die jüngsten Veränderungen in den normativen Grundlagen und bauaufsichtlichen Regelungen eingegangen und im Hinblick auf Sicherheitsaspekte bewertet. Die Verringerung der Teilsicherheit für den Bauteilwiderstand nicht stabilitätsgefährdeter Bauteile im Regelwerk für die Kaltbemessung von Stahltragwerken ist hier als besonders kritisch anzusehen, da hierdurch ein systematisches Sicherheitsdefizit für den Brandfall verursacht wird. Weiterhin werden neuste Forschungsergebnisse bei der Entwicklung von Bewertungsregeln von reaktiven Brandschutzsystemen auf Vollkreisprofilen unter Zugbeanspruchung vorgestellt und diskutiert. Die Untersuchungen behandeln die Fragestellung, inwieweit Prüfungen mit Zugbeanspruchungen an Kreisvollprofilen erforderlich sein werden. KW - Stahlkonstruktion KW - Brandschutz KW - Reaktive Brandschutzsysteme KW - Zugglieder PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-307949 DO - https://doi.org/10.2314/GBV:77999762X SP - 141 EP - 148 PB - Institut für Stahlbau / Leibniz Universität Hannover CY - Hannover AN - OPUS4-30794 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Illerhaus, Bernhard A1 - Onel, Yener T1 - Mehr Strom oder mehr Spannung, ein Vergleich drei Röntgenröhren in der CT N2 - Sollten CT Aufnahmen quantitativ und automatisch ausgewertet werden, ist die Qualität der Tomogramme ein wesentlicher Punkt. Außerdem steht bei Serienmessungen nur eine begrenzte Meßzeit für jede Probe. Es werden die verschiedenen Mikrofokusröhren in Bezug auf die Parameter Orts- und Dichteauflösung, sowie Meßzeit verglichen, CT Beispiele dazu gezeigt. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Computertomographie KW - Ortsauflösung KW - Röhrenvergleich PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-307629 SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.1A.1, 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-30762 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Franziska A1 - Scholz, G. A1 - Benemann, Sigrid A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Evaluation of the formation pathways of cocrystal polymorphs in liquid-assisted syntheses N2 - The synthesis of the polymorphic cocrystal caffeine:anthranilic acid was investigated to obtain a better understanding of the processes leading to the formation of different polymorphic forms. In the case of these cocrystal polymorphs synthesized by liquid-assisted grinding a distinct influence of the dipole moment of the solvent was found. A pre-coordination between the solvent molecules and the caffeine:anthranilic acid cocrystal could be identified in the formation of form II. In the case of form II the solvent can be regarded as a catalyst. The formation pathway of each polymorph was evaluated using synchrotron X-ray diffraction. KW - cocrystal KW - synchrotron X-ray diffraction KW - caffeine PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-313222 DO - https://doi.org/10.1039/c4ce00472h SN - 1466-8033 VL - 16 IS - 35 SP - 8272 EP - 8278 CY - London, UK AN - OPUS4-31322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Schade, U. A1 - Aziz, E. F. A1 - Wolff, Dietmar T1 - Fourier-spektroskopische Untersuchungen im mittleren- und fernen Infrarotbereich an Co-60 bestrahlten und thermisch belasteten ultrahochmolekularen Polyethylen-Proben N2 - Fourier-Spektroskopische Untersuchungen von hochmolekularem Polyethylen (HMW-PE) und ultrahochmolekularem Polyethylen (UHMW-PE) im Mittleren - und Fernen Infrarotbereich können Veränderungen der molekularen Strukturen nachweisen, die durch Co60 γ-Strahlung und Rekristallisationsprozesse initiiert werden. UHMW-PE und HMW-PE sind im gewählten IR-Bereich unterscheidbar. Die integrale Absorption der B1u – Gitterschwingungen im Fernen Infrarotbereich (THz-Bereich) ermöglichen die quantitative Beschreibung des Kristallinitätsgrades und dessen Abbau. Die Bildung ungesättigter Vinylengruppen und der Abbau ungesättigter Methylengruppen können im Mittleren Infrarotbereich nachgewiesen werden. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Infrared and far-infrared spectroscopy KW - Polyethylene KW - Co-60 irradiation PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-313317 SN - 978-3-940283-61-0 VL - 148 SP - 1 EP - 7 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-31331 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gravenkamp, Hauke A1 - Song, C. T1 - Innovative numerische Methoden zur Simulation geführter Ultraschallwellen N2 - Geführte Ultraschallwellen bieten eine Vielzahl von Einsatzmöglichkeiten in der Zerstörungsfreien Prüfung, der Zustandsüberwachung sowie der Materialcharakterisierung. Insbesondere für Rohrleitungen und ausgedehnte Plattenstrukturen ist eine Vielzahl von auf geführten Wellen basierenden Verfahren in der Entwicklung und teilweise bereits im Einsatz. Aufgrund des komplexen Ausbreitungsverhaltens geführter Wellen werden numerische Verfahren (etwa die Finite Elemente Methode (FEM) oder die Randelementemethode (BEM)) zur Simulation der Wellenausbreitung sowie der Wechselwirkung mit Defekten in Wellenleitern angewendet. Diese Methoden sind für große Strukturen extrem rechenintensiv und umständlich in der Anwendung. Ein ungleich effizienteres Verfahren wurde kürzlich von den Autoren auf Grundlage der Scaled Boundary Finite Element Method entwickelt. Ein semi-analytischer Ansatz erlaubt die Modellierung beliebig ausgedehnter Strukturen bei extrem kurzen Rechenzeiten. Die Wechselwirkung geführter Wellen mit Rissen kann auf besonders elegante und exakte Weise beschrieben werden. Mit dieser Methode können die komplexen Vorgänge in Wellenleitern innerhalb weniger Sekunden modelliert werden. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.04.2014 PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-313610 SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Poster 66, 1 EP - 6 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-31361 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Christina A1 - Zorn, R. A1 - Emmerling, Franziska A1 - Falkenhagen, Jana A1 - Frick, B. A1 - Huber, P. A1 - Schönhals, Andreas T1 - Vibrational density of states of triphenylene based discotic liquid crystals: dependence on the length of the alkyl chain N2 - The vibrational density of states of a series of homologous triphenylene-based discotic liquid crystals HATn (n = 5, 6, 8, 10, 12) depending on the length of the aliphatic side chain is investigated by means of inelastic neutron scattering. All studied materials have a plastic crystalline phase at low temperatures, followed by a hexagonally ordered liquid crystalline phase at higher temperatures and a quasi isotropic phase at the highest temperatures. The X-ray scattering pattern for the plastic crystalline phase of all materials shows a sharp Bragg reflection corresponding to the intercolumnar distance in the lower q-range and a peak at circa 17 nm-1 related to intracolumnar distances between the cores perpendicular to the columns as well as a broad amorphous halo related to the disordered structure of the methylene groups in the side chains in the higher q-range. The intercolumnar distance increases linearly with increasing chain length for the hexagonal columnar ordered liquid crystalline phase. A similar behaviour is assumed for the plastic crystalline phase. Besides n = 8 all materials under study exhibit a Boson peak. With increasing chain length, the frequency of the Boson peak decreases and its intensity increases. This can be explained by a self-organized confinement model. The peaks for n = 10, 12 are much narrower than for n = 5, 6 which might imply the transformation from a rigid system to a softer one with increasing chain length. Moreover the results can also be discussed in the framework of a transition from an uncorrelated to a correlated disorder with increasing n where n = 8 might be speculatively considered as a transitional state. KW - X-ray scattering KW - Neutron scattering KW - Differential scanning calorimetry PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304789 DO - https://doi.org/10.1039/c3cp55303e SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 16 SP - 7324 EP - 7333 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Bruno, Giovanni A1 - Müller, Bernd R. T1 - Direkte Röntgenrefraktion an Mikrostrukturen N2 - Die durch Brechung an Mikrostrukturen abgelenkte Röntgenstrahlung wird direkt zweidimensional abgebildet. Dazu werden Modellproben einfacher Geometrie (Fasern, Kapillaren, monodisperse Nano- und Mikropartikel) mit einem auf 50 µm kollimierten Synchrotronstrahl (20 keV) gescannt. Die nach den Regeln der geometrischen Optik an prismatischen und linsenartigen Grenzflächen abgelenkte Strahlung wird in etwa 3 Metern Entfernung von einem Flächendetektor mit 7 µm Ortsauflösung zusätzlich zu der ungestörten Resttransmission des Primärstrahls registriert. In der Abfolge der Radiogramme werden die lokalen Orientierungsänderungen der Probekörper-Grenzflächen bei deren Abtastung mit wenigen Mikrometern Schrittweite bildhaft verfolgt. Mit der hier erreichten Winkelauflösung von etwa 3 Bogensekunden (Streuvektor-Inkremente Δk = 10-3nm-1) kann bei 50 µm Ortsauflösung das Materialvolumen bezüglich innerer Grenzflächen mit Nanometer-Separation auch bei hohen Abtastraten unterhalb einer Sekunde pro Bild charakterisiert werden. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Computertomographie (CT) KW - Rekonstruktionsalgorithmus KW - DIRECTT KW - Missing wedge KW - Statistische Bewertung PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312931 UR - http://www.ndt.net/article/dgzfp2014/papers/di1b2.pdf SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.1.B.2, 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-31293 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Hentschel, Manfred P. A1 - Onel, Yener A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Wolk, Thomas A1 - Staude, Andreas A1 - Ehrig, Karsten A1 - Müller, Bernd R. T1 - Bewertung von Porositätsparametern in Cordierit-Diesel-Partikelfilter-Materialien mit fortgeschrittenen Röntgenverfahren und statistischer Analyse N2 - Bikontinuierliche poröse Keramiken für Filteranwendungen weisen eine komplizierte Mikrostruktur auf, in der Poren und Festkörperphase 'vermischt' sind. Mechanische, thermische sowie Filtereigenschaften können nur präzise bestimmt werden, wenn die Morphologie beider Phasen quantitativ angegeben werden kann. Hier werden unter Anwendung von 3D Computertomographie (CT) und verschiedenen Techniken, die auf der Röntgenrefraktion basieren, die Porosität und die Porenorientierung in keramischen Cordierit-Dieselpartikelfiltern bewertet. Dabei werden zur Auswertung der Tomogramme die Fouriertransformierten sowie eine neu entwickelte richtungssensitive Bildanalyse (DIVA, directional interface variance analysis) angewandt. Sowohl die genannten Messtechniken als auch der statistische Ansatz gestatten die Extraktion optional ortsaufgelöster oder gemittelter Werte. Es ergeben sich sehr gute Übereinstimmungen der experimentell ermittelten Porositätswerte mit Ergebnissen aus Quecksilberintrusionsversuchen als auch der ermittelten Porenorientierung im Vergleich zu publizierten Angaben zur kristallographischen Textur. Dies legt den Schluss nahe, dass die Kenntnis der Grenzflächen (zwischen Poren und Materie) genügt, die morphologischen Eigenschaften solcher Materialien hinreichend zu beschreiben. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Cordierit KW - Poröse Keramik KW - Porenorientierung KW - Röntgenrefraktion KW - Computer-Tomographie KW - 3D-Mikrostruktur PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312946 SN - 978-3-940283-61-0 VL - 148 SP - 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-31294 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Lück, S. A1 - Schmidt, V. A1 - Grothausmann, R. A1 - Hilger, A. A1 - Manke, I. T1 - Reduzierung von Missing-Wedge-Artefakten mit DIRECTT N2 - Wir stellen eine Prozedur vor, mit der typische 'Missing Wedge' (MW)-Artefakte in CT-Rekonstruktionen effektiv unterdrückt werden können. Dazu wird der iterative DIRECTT-Algorithmus (Direkte Iterative Rekonstruktion Computertomographischer Trajektorien) mit einigen Zyklen diskreter Rekonstruktion eingesetzt. Die Kernfunktionen des Algorithmus', die wiederholte Auswahl und Gewichtung von Elementen einer Zwischenkonstruktion, werden beibehalten. Abgesehen von Sonderfällen der Röntgen- und Neutronentomographie tritt die MW-Restriktion (neben einer Vielzahl anderer) in Standardkonfigurationen der Elektronentomographie auf. Um den MW-Effekt isoliert zu untersuchen und beurteilen zu können, werden hier vollständige experimentelle Datensätze einer bekannten Porenstruktur um einen Sektor beschnitten sowie MW-Rekonstruktionen von Porenmodellen erzeugt. Die Ergebnisse werden mit zurzeit verbreiteten Algorithmen (Gefilterte Rückprojektion (FBP) und ART-Varianten) verglichen. Die Bewertung im Fourierraum zeigt, dass DIRECTT die fehlende Information im MW erfolgreich ergänzt. Zur quantitativen Bewertung der lokalen Rekonstruktionsqualität werden Methoden der räumlichen Statistik eingesetzt. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Computertomographie (CT) KW - Rekonstruktionsalgorithmus KW - DIRECTT KW - Missing Wedge KW - Statistische Bewertung PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312977 SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Poster 18, 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-31297 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agirrezabal-Telleria, Iker A1 - Guo, Y. A1 - Hemmann, Felix A1 - Arias, P. L. A1 - Kemnitz, E. T1 - Dehydration of xylose and glucose to furan derivatives using bifunctional partially hydroxylated MgF2 catalysts and N2-stripping N2 - The current furfural production yield is low due to the use of non-selective homogeneous catalysts and expensive separation. In this work, partially hydroxylated MgF2 catalysts, synthesized using different water contents, were screened during xylose dehydration in water–toluene at 160 °C. The different Lewis/Brønsted ratios on the MgF2 catalysts showed that under-coordinated Mg can isomerize xylose to xylulose, whilst the surface OH-groups were responsible for the dehydration reactions. The presence of glucose as a co-carbohydrate reduced the furfural selectivity from 86 to 81%, whilst it also led to high 5-hydroxymethylfurfural selectivity. The tests catalyzed by MgF2 in combination with simultaneous N2-stripping showed that a furfural selectivity of 87% could be achieved using low xylose loadings. Moreover, the catalysts regenerated by H2O2 showed high activity during the dehydration tests in water–toluene at 160 °C. KW - Bifunctional MgF2 KW - Lewis/Bronsted KW - Carbohydrates KW - Furan derivatives KW - N2-stripping PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-305441 DO - https://doi.org/10.1039/c4cy00129j SN - 2044-4753 SN - 2044-4761 VL - 4 IS - 5 SP - 1357 EP - 1368 PB - RSC Publ. CY - Cambridge AN - OPUS4-30544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karabeliov, Krassimire A1 - Baeßler, Matthias A1 - Cuéllar, Pablo A1 - Rücker, Werner T1 - A method for system identification of a structure supported by nonlinear springs using evolutionary computing N2 - A mechanical structure supported by nonlinear springs subjected to an external load is considered. If all mechanical parameters of the system were known, the displacement of the system subjected to this load could be easily calculated. If not all of the parameters are known, but the load and the displacement are measured at one location, an inverse problem exists. In the presented problem the nonlinear springs are unknown and have to be determined. At first glance a problem needs to be solved, which is underdetermined due to the number of unknown variables. However, evolutionary computing can be applied to solve this inverse, nonlinear and multimodal problem. Sometimes a prior knowledge exists on certain system properties, which is difficult to implement into analytical or numerical solver. This knowledge can play a decisive role in identifying the system properties and it can be easily included as boundary condition when applying evolutionary algorithm. This article examines how and under what conditions the spring resistances can be identified. The procedure is exemplified at a mechanical system of a pile foundation. T2 - 2nd International conference on mathematical modeling in physical sciences 2013 CY - Prague, Czech Republic DA - 01.09.2013 PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304531 UR - http://iopscience.iop.org/1742-6596/490/1/012095/pdf/1742-6596_490_1_012095.pdf DO - https://doi.org/10.1088/1742-6596/490/1/012095 SN - 1742-6588 SN - 1742-6596 VL - 490 IS - 012095 SP - 1 EP - 4 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-30453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stengel, Dominik A1 - Mehdianpour, Milad T1 - Finite element modelling of electrical overhead line cables under turbulent wind load N2 - This paper presents a finite element model of an overhead transmission line using so called cable elements which allow reproducing the cable's nonlinear characteristics accurately employing only a few elements. Aerodynamic damping is considered in the equation of motion by taking into account the relative velocity between the flow of the wind and the moving structure. The wind flow itself is simulated by wave superposition making necessary assumptions on the lateral correlation between the wind velocities along the cable length. As result from the simulation, the following conclusions can be drawn. The first natural frequency of generally used wide spanning cables lies well below 1 Hz where also most of the energy content of the wind excitation is to be expected. Aerodynamic damping is significant for the moving cables holding very low structural damping which leads to a suppression of resonant amplification. This is particularly of interest regarding the support reaction which is dominated by the mean value and the so called background response. The latter is mostly influenced by the randomness of the wind flow, especially lateral to the main wind direction. KW - Nonlinear Finite Element Formulations KW - Nonlinear Equation of Motion KW - Turbulent Wind Excitation PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304567 DO - https://doi.org/10.1155/2014/421587 SN - 2314-6494 SN - 2356-766X VL - 2014 IS - Article ID 421587 SP - 1 EP - 8 PB - Hindawi Publ. CY - New York, NY ; Cairo AN - OPUS4-30456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Noack-Schönmann, Steffi A1 - Bus, T. A1 - Banasiak, Ronald A1 - Knabe, Nicole A1 - Broughton, William J. A1 - Dulk-Ras, H.D. A1 - Hooykaas, P.J.J. A1 - Gorbushina, Anna T1 - Genetic transformation of Knufia petricola A95 - a model organism for biofilm-material interactions N2 - We established a protoplast-based system to transfer DNA to Knufia petricola strain A95, a melanised rock-inhabiting microcolonial fungus that is also a component of a model sub-aerial biofilm (SAB) system. To test whether the desiccation resistant, highly melanised cell walls would hinder protoplast formation, we treated a melanin-minus mutant of A95 as well as the type-strain with a variety of cell-degrading enzymes. Of the different enzymes tested, lysing enzymes from Trichoderma harzianum were most effective in producing protoplasts. This mixture was equally effective on the melanin-minus mutant and the type-strain. Protoplasts produced using lysing enzymes were mixed with polyethyleneglycol (PEG) and plasmid pCB1004 which contains the hygromycin B (HmB) phosphotransferase (hph) gene under the control of the Aspergillus nidulans trpC. Integration and expression of hph into the A95 genome conferred hygromycin resistance upon the transformants. Two weeks after plating out on selective agar containing HmB, the protoplasts developed cell-walls and formed colonies. Transformation frequencies were in the range 36 to 87 transformants per 10 µg of vector DNA and 106 protoplasts. Stability of transformation was confirmed by sub-culturing the putative transformants on selective agar containing HmB as well as by PCR-detection of the hph gene in the colonies. The hph gene was stably integrated as shown by five subsequent passages with and without selection pressure. KW - DNA transfer KW - Fungal cell-walls KW - Protoplasts KW - Hygromycin resistance KW - Black yeast KW - Sub-aerial biofilms KW - Stress-protective morphology KW - Ancestor of opportunistic pathogens & lichens PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-320840 UR - http://www.amb-express.com/content/4/1/80 DO - https://doi.org/10.1186/s13568-014-0080-5 SN - 2191-0855 VL - 4 SP - 80, 1 EP - 6 PB - Springer CY - Heidelberg AN - OPUS4-32084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kopyra, J. A1 - Keller, A. A1 - Bald, Ilko T1 - On the role of fluoro-substituted nucleosides in DNA radiosensitization for tumor radiation therapy N2 - Gemcitabine (2',2'-difluorocytidine) is a well-known radiosensitizer routinely applied in concomitant chemoradiotherapy. During irradiation of biological media with high-energy radiation secondary low-energy (<10 eV) electrons are produced that can directly induce chemical bond breakage in DNA by dissociative electron attachment (DEA). Here, we investigate and compare DEA to the three molecules 2'-deoxycytidine, 2'-deoxy-5-fluorocytidine, and gemcitabine. Fluorination at specific molecular sites, i.e., nucleobase or sugar moiety, is found to control electron attachment and subsequent dissociation pathways. The presence of two fluorine atoms at the sugar ring results in more efficient electron attachment to the sugar moiety and subsequent bond cleavage. For the formation of the dehydrogenated nucleobase anion, we obtain an enhancement factor of 2.8 upon fluorination of the sugar, whereas the enhancement factor is 5.5 when the nucleobase is fluorinated. The observed fragmentation reactions suggest enhanced DNA strand breakage induced by secondary electrons when gemcitabine is incorporated into DNA. KW - Dissociative electron attachment KW - DNA radiation damage KW - Gemcitabine KW - DNA radiosensitizer KW - Tumor radiation therapy PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-302872 DO - https://doi.org/10.1039/c3ra46735j SN - 2046-2069 VL - 4 IS - 13 SP - 6825 EP - 6829 PB - RSC Publishing CY - London AN - OPUS4-30287 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ehlert, Christopher A1 - Unger, Wolfgang A1 - Saalfrank, P. T1 - C K-edge NEXAFS spectra of graphene with physical and chemical defects: a study based on density functional theory N2 - Recently, C K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of graphite (HOPG) surfaces have been measured for the pristine material, and for HOPG treated with either bromine or krypton plasmas (Lippitz et al., Surf. Sci., 2013, 611, L1). Changes of the NEXAFS spectra characteristic for physical (krypton) and/or chemical/physical modifications of the surface (bromine) upon plasma treatment were observed. Their molecular origin, however, remained elusive. In this work we study by density functional theory, the effects of selected point and line defects as well as chemical modifications on NEXAFS carbon K-edge spectra of single graphene layers. For Br-treated surfaces, also Br 3d X-ray Photoelectron Spectra (XPS) are simulated by a cluster approach, to identify possible chemical modifications. We observe that some of the defects related to plasma treatment lead to characteristic changes of NEXAFS spectra, similar to those in experiment. Theory provides possible microscopic origins for these changes. KW - Graphene KW - NEXAFS KW - Spectrum simulation KW - Density functional theory PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-309658 DO - https://doi.org/10.1039/c4cp01106f SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 27 SP - 14083 EP - 14095 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-30965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vöse, Markus A1 - Fedelich, Bernard A1 - Otto, F. A1 - Eggeler, G. T1 - Micromechanical modeling of creep damage in a copper-antimony alloy N2 - A micromechanical model of creep induced grain boundary damage is proposed, which allows for the simulation of creep damage in a polycrystal with the finite element method. Grain boundary cavitation and sliding are considered via a micromechanically motivated cohesive zone model, while the grains creep following the slip system theory. The model has been calibrated with creep test data from pure Cu single crystals and a coarse-grained polycrystalline Cu-Sb alloy. The test data includes porosity measurements and estimates of grain boundary sliding. Finally, the model has been applied to Voronoi models of polycrystalline structures. In particular the influence of grain boundary sliding on the overall creep rate is demonstrated. T2 - ECF20 - 20th European conference on fracture CY - Trondheim, Norway DA - 28.06.2014 KW - Creep damage KW - Grain boundary sliding KW - Cohesive zone KW - Micromechanical model KW - Polycrystal PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-309914 DO - https://doi.org/10.1016/j.mspro.2014.06.006 SN - 2211-8128 VL - 3 SP - 21 EP - 26 PB - Curran CY - Red Hook, NY, USA AN - OPUS4-30991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Bauer, P. A1 - Caspers, F. A1 - Heck, S. A1 - Müller, F. A1 - Pohl, Rainer A1 - Scheuerlein, C. A1 - Sickert, Roland A1 - Maierhofer, Christiane A1 - Brackrock, Daniel T1 - Sensoren für Verbunddrähte aus Niob-Titan und Kupfer N2 - Der Large Hadron Collider (LHC) des europäischen Kernforschungszentrums CERN ist einer der weltweit größten und leistungsfähigsten Teilchenbeschleuniger. Um den Teilchenstrahl auf seiner Kreisbahn zu halten, werden mit Hilfe supraleitender Spulen sehr starke Magnetfelder erzeugt. Die hierzu benötigten hohen Ströme werden über Verbunddrähte aus Niob-Titan und Kupfer geleitet. Die Drähte werden u.a. durch Ultraschallschweißungen miteinander verbunden. Eine mangelhafte Verbindung kann zur Erwärmung der Kontaktstelle und in Folge davon zum Zusammenbruch der Supraleitung führen. Auf Anfrage des CERN wurden an der BAM Untersuchungen zur Prüfbarkeit solcher Verbindungen bei Umgebungstemperatur durchgeführt. Es gelang, für einen Verbindungstypen einen Wirbelstromsensor für eine manuelle Prüfung zu entwickeln. Ein Prototyp des Sensors befindet sich beim CERN in der praktischen Erprobung. Das Sensorprinzip sowie Prüfergebnisse aus Labor und Praxis werden vorgestellt. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Ultraschallprüfung mit Matrix-Sensoren KW - Aktive Thermografie KW - Gabelsensor PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-319785 SN - 978-3-940283-61-0 VL - 148 SP - 1 EP - 12 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-31978 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, B. A1 - Krahl, T. A1 - Rurack, Knut A1 - Kemnitz, E. T1 - Nanoscale CaF2 doped with Eu3+ and Tb3+ through fluorolytic sol-gel synthesis N2 - In this article, the high potential of the fluorolytic sol–gel process to synthesize nanoscopic rare earth-doped calcium fluoride sols is shown. Through a fluorolytic sol–gel process we manage to achieve spherical monodisperse ~5 nm sized nanoparticles using a simple and reproducible one-pot-wet chemical route at room temperature. The as-synthesized clear sols exhibit an intense red and green luminescence under UV excitation at room temperature. A spectroscopic study of the sols revealed the characteristic transitions 5D0 → 7FJ of Eu3+ and 5D4 → 7FJ of Tb3+, with 5D0 → 7F2 (611 nm) of Eu3+ and 5D4 → 7F4 (581 nm) of Tb3+ as the most prominent transitions. This facile synthetic strategy is also valuable for developing other luminescent nanoparticles. KW - Calciumfluorid KW - Europium KW - Lumineszenz KW - Nanopartikel KW - Sol-Gel-Synthese KW - Terbium PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-320120 DO - https://doi.org/10.1039/c4tc01073f SN - 2050-7526 SN - 2050-7534 VL - 2 IS - 40 SP - 8607 EP - 8613 PB - Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-32012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ressnig, A. A1 - Corbiere, T. A1 - Lunkenbein, T. A1 - Braun, Ulrike A1 - Willinger, M. G. A1 - Antonietti, M. T1 - Decomposition synthesis of tuneable, macroporous carbon foams from crystalline precursors via in situ templating N2 - A flexible, sustainable, one-step thermal decomposition route for the synthesis of hierarchical, heteroatom doped carbon foams is presented. Task-specific semi-organic crystals combine functions for three different purposes: the carbon and heteroatom source, a foaming agent (CO2) and an in situ generable template (NaCl). Insights to the decomposition pathway were gained through FTIR/MS coupled TGA and an ultrafast out-of-furnace heating procedure and the products were analysed with (HR)SEM/TEM, EELS, FTIR, and N2 sorption. The resulting macroporous carbon foams are excellent supports for metallic nanoparticles due to their hierarchical structure, high surface area and tuneable heteroatom contents. This was demonstrated for catalytically active copper or the magnetic CoNi alloy for water purification. KW - macroporous carbon KW - thermal decomposition KW - synthesize heteroatom KW - in situ template (NaCl) PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-318641 DO - https://doi.org/10.1039/c4ta03646h SN - 2050-7496 SN - 2050-7488 VL - 2 IS - 42 SP - 18076 EP - 18081 PB - RSC CY - London [u.a.] AN - OPUS4-31864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Sabine A1 - Niederleithinger, Ernst T1 - Anwendung der Reverse Time Migration auf Ultraschall-Echo-Messungen in der zerstörungsfreien Prüfung im Bauwesen N2 - Ultraschall-Echo-Messungen dienen im Bauwesen zur Dickenbestimmung von Bauteilen sowie der Lokalisierung und Charakterisierung von Einbauteilen, Einlagerungen und anderen Inhomogenitäten. Zur Rekonstruktion werden bisher Abbildungsverfahren wie z.B. 3D-SAFT genutzt. Diese setzen aber voraus, dass direkte Reflexionen am Abbildungsobjekt erfolgen. Deshalb können keine zuverlässigen Aussagen über den Durchmesser von eingebauten Spannkanälen oder z. B. Seitenkanten von Objekten getroffen werden. Ziel laufender Forschungsarbeiten ist es, die Abbildungsqualität zu verbessern. Mit der aus der Geophysik stammenden Reverse Time Migration, die bereits häufig in der Erdölexploration genutzt wird, lassen sich auch steilere Strukturen über 70° abbilden und somit auch die Unterseite von Einbauten oder Stufen in Bauteilen darstellen. Um die Leistungsfähigkeit des Algorithmus für die zerstörungsfreie Prüfung zu untersuchen, wurden verschiedene Simulationsrechnungen durchgeführt. Dabei wurden typische Prüfprobleme unterschiedlicher Komplexität zunächst in Polyamid nachgestellt. Die Schwerpunkte lagen bei der Darstellung senkrechter Grenzflächen und Hohlstellen. Die Rechnungen dienten neben der Evaluierung und Optimierung des Verfahrens auch der Planung von Experimenten an Probekörpern mit verschiedenen Einbauten. Die Simulationsergebnisse wurden an einem dem synthetischen Modell entsprechenden Polyamidprobekörper überprüft, an dem rauscharme Ultraschalldaten aufgenommen werden konnten. In einer Messreihe wurde in den Probekörper eine Bohrung eingebracht und schrittweise vergrößert. Mit diesen Messungen konnte die Leistungsfähigkeit der Reverse Time Migration auch an realen Ultraschalldaten nachgewiesen werden. Untersuchungen mit an Beton aufgenommenen Ultraschalldaten werden folgen. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Ultraschall KW - Reverse Time Migration KW - Zerstörungsfreie Prüfung PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-319311 SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.1.C.4, 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-31931 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mozetic, M. A1 - Ostrikov, K. A1 - Ruzic, D.N. A1 - Curreli, D. A1 - Cvelbar, U. A1 - Vesel, A. A1 - Primc, G. A1 - Leisch, M. A1 - Jousten, K. A1 - Malyshev, O.B. A1 - Hendricks, J.H. A1 - Kövér, L. A1 - Tagliaferro, A. A1 - Conde, O. A1 - Silvestre, A.J. A1 - Giapintzakis, J. A1 - Buljan, M. A1 - Radic, N. A1 - Drazic, G. A1 - Bernstorff, S. A1 - Biedermann, H. A1 - Kylián, O. A1 - Hanus, J. A1 - Milosevic, S. A1 - Galtayries, A. A1 - Dietrich, Paul A1 - Unger, Wolfgang A1 - Lehocky, M. A1 - Sedlarik, V. A1 - Stana-Kleinschek, K. A1 - Drmota-Petric, A. A1 - Pireaux, J.J. A1 - Rogers, J.W. A1 - Anderle, M. T1 - Recent advances in vacuum sciences and applications N2 - Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid–liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented. KW - Vacuum KW - Surface KW - Plasma KW - Interface KW - Nanoscience PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304884 DO - https://doi.org/10.1088/0022-3727/47/15/153001 SN - 0022-3727 SN - 1361-6463 VL - 47 IS - 15 SP - 153001-1 EP - 153001-23 PB - IOP Publ. CY - Bristol AN - OPUS4-30488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Myrach, Philipp A1 - Maierhofer, Christiane A1 - Reischel, Mercedes A1 - Rahammer, M. A1 - Holtmann, N. T1 - Untersuchung der Auflösungsgrenzen der Lockin-Thermografie zur Prüfung von Faserverbundwerkstoffen N2 - Aktive Thermografie mit Lockin-Anregung stellt ein berührungsfreies und zerstörungsfreies Prüfverfahren dar, welches insbesondere auch die Prüfung von kohlenstofffaserverstärkten Kunststoffen ermöglicht. Um eine Standardisierung dieses Verfahrens voranzubringen, wurden im Rahmen eines Forschungsprojektes umfangreiche Untersuchungen zur Validierung des Verfahrens durchgeführt. Dabei wurden unter anderem der Einfluss der spektralen Empfindlichkeit verschiedener Kamerasysteme, unterschiedlicher Lagenaufbauten bei CFK-Probekörpern und der Einfluss einer Phasenverschiebung zwischen dem Anregungssignal und der Detektion der Thermografiebilder untersucht. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Aktive Thermografie KW - Lockin-Thermografie KW - CFK PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-309259 SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.3.C.3, 1 EP - 10 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-30925 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ecker, Melanie A1 - Pretsch, Thorsten T1 - Novel design approaches for multifunctional information carriers N2 - Two design approaches for multifunctional information carriers are introduced. In the first one, quick response (QR) code carriers, which were composed of poly(ester urethane) (PEU) and microencapsulated thermochromic pigments (T-PIGs), differing in color and color switching temperature (CST), were prepared. The obtained material systems exhibited machine-readable QR codes at 23 °C and a two-stage decolorization when heated, culminating in unreadable QR codes at temperatures above the highest CST of the employed T-PIGs. In the second scenario, information carriers were sealed with a dark, thermochromic PEU layer. As a result, the QR codes were hidden at 23 °C and became readable upon heating due to color fading. Beyond the characterization of the employed components, preparation methods, functionality analyses and durability investigations are reported. When heated after thermo-mechanical programming, pronounced shape memory properties could be verified. The thermo-responsiveness of such multifunctional material systems may qualify them for usage in anti-counterfeiting applications. KW - Poly(ester urethane) KW - Shape memory polymer KW - Thermo-responsiveness KW - Information carrier KW - QR code carrier KW - Thermochromic properties KW - Microencapsulated thermochromic pigments KW - Anti-counterfeiting KW - Smart label KW - Difficult-to-copy KW - Durability KW - Multifuncitonal material systems PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-315176 DO - https://doi.org/10.1039/c4ra08977d SN - 2046-2069 VL - 4 IS - 87 SP - 46680 EP - 46688 PB - RSC Publishing CY - London AN - OPUS4-31517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Batzdorf, Lisa A1 - Emmerling, Franziska T1 - Mechanochemical synthesis and characterisation of cocrystals and metal-organic compounds N2 - The mechanochemical synthesis of two model compounds, a metal organic framework ([Bi(1,4-bdc)2]*(Im) (bdc = benzene dicarboxylate, Im = imidazole cation)) and a cocrystal (Carbamazepine:Indometacin 1:1) were followed ex situ by combined analytical methods. Powder X-ray diffraction (XRD) and Raman spectroscopy data were evaluated for the synthesis of the metal organic framework. XRD measurements and REM images were analysed for the synthesis of the cocrystal. The measurements revealed that both model compounds were synthesised within minutes. The metal organic framework [Bi(1,4-bdc)2]*(Im) is synthesised via an intermediate structure. The cocrystal Carbamazepine:Indometacin 1:1 is formed within few seconds and afterwards the crystallite size decreases extremely. KW - Powder X-ray diffraction (XRD) KW - Raman spectroscopy KW - mechanochemical synthesis PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-306305 UR - http://pubs.rsc.org/en/content/articlepdf/2014/fd/c3fd00163f DO - https://doi.org/10.1039/C3FD00163F SN - 1359-6640 SN - 1364-5498 N1 - Geburtsname von Batzdorf, Lisa: Tröbs, L. - Birth name of Batzdorf, Lisa: Tröbs, L. SP - 109 EP - 119 PB - RSC CY - Cambridge [u.a.] AN - OPUS4-30630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Thomas A1 - Traulsen, Christoph Hans-Henning A1 - Darlatt, Erik A1 - Richter, S. A1 - Poppenberg, J. A1 - Traulsen, N.L. A1 - Linder, I. A1 - Lippitz, Andreas A1 - Dietrich, Paul A1 - Dib, B. A1 - Unger, Wolfgang A1 - Schalley, C.A. T1 - The versatility of 'Click' reactions at surfaces: Molecular recognition at interfaces N2 - In order to investigate molecular recognition on surfaces, an azide-functionalized monolayer was deposited on gold. The monolayer was characterized by X-ray photoelectron spectroscopy (XPS) and angle-resolved near-edge X-ray absorption fine structure (NEXAFS) experiments and the decomposition of the azide upon irradiation with X-ray beams was investigated. Subsequently, various alkyne-functionalized host and guest molecules were attached to the azide by 1,3-dipolar cycloaddition. These modified surfaces and their host–guest chemistry were analysed by XPS and angle-resolved NEXAFS. The reversibility of guest binding was shown for one example as a proof of principle. KW - 'Click' reaction KW - Azide-terminated surfaces KW - SAMs KW - Host guest molecules KW - Molecular recognition at interfaces PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-306463 DO - https://doi.org/10.1039/C4RA01730G SN - 2046-2069 VL - 4 IS - 34 SP - 17694 EP - 17702 PB - RSC Publishing CY - London AN - OPUS4-30646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bald, Ilko A1 - Keller, A. T1 - Molecular processes studied at a single-molecule level using DNA origami nanostructures and atomic force microscopy N2 - DNA origami nanostructures allow for the arrangement of different functionalities such as proteins, specific DNA structures, nanoparticles, and various chemical modifications with unprecedented precision. The arranged functional entities can be visualized by atomic force microscopy (AFM) which enables the study of molecular processes at a single-molecular level. Examples comprise the investigation of chemical reactions, electron-induced bond breaking, enzymatic binding and cleavage events, and conformational transitions in DNA. In this paper, we provide an overview of the advances achieved in the field of single-molecule investigations by applying atomic force microscopy to functionalized DNA origami substrates. KW - DNA origami KW - atomic force microscopy KW - single-molecule analysis KW - DNA radiation damage KW - protein binding KW - enzyme reactions KW - G quadruplexes PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314343 DO - https://doi.org/10.3390/molecules190913803 SN - 1420-3049 VL - 19 IS - 9 SP - 13803 EP - 13823 PB - MDPI CY - Basel AN - OPUS4-31434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, Marcel A1 - Avilov, Vjaceslav A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Experimental and numerical investigation of an electromagnetic weld pool control for laser beam welding N2 - The objective of this study was to investigate the influence of externally applied magnetic fields on the weld quality in laser beam welding. The optimization of the process parameters was performed using the results of computer simulations. Welding tests were performed with up to 20 kW laser beam power. It was shown that the AC magnet with 3 kW power supply allows for a prevention of the gravity drop-out for full penetration welding of 20 mm thick stainless steel plates. For partial penetration welding it was shown that an0.5 T DC magnetic field is enough for a suppression of convective flows in the weld pool. Partial penetration welding tests with 4 kW beam power showed that the application of AC magnetic fields can reduce weld porosity by a factor of 10 compared to the reference joints. The weld surface roughness was improved by 50%. KW - Laser beam welding KW - Electromagnetic weld pool support KW - Hartmann effect KW - Electromagnetic rectification PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314405 DO - https://doi.org/10.1016/j.phpro.2014.08.006 SN - 1875-3892 VL - 56 SP - 515 EP - 524 PB - Elsevier B.V. CY - Amsterdam [u.a.] AN - OPUS4-31440 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zocca, Andrea A1 - Wirth, Cynthia A1 - Mühler, T. A1 - Günster, Jens T1 - Powder-bed stabilization for powder-based additive manufacturing N2 - The most successful additive manufacturing (AM) technologies are based on the layer-by-layer deposition of a flowable powder. Although considered as the third industrial revolution, one factor still limiting these processes to become completely autonomous is the often necessary build-up of support structures. Besides the prevention of lateral shifts of the part during the deposition of layers, the support assures quality and stability to the built process. The loose powder itself surrounding the built object, or so-called powder-bed, does not provide this sustenance in most existent technology available. Here we present a simple but effective and economical method for stabilizing the powder-bed, preventing distortions in the geometry with no need for support structures. This effect, achieved by applying an air flow through the powder-bed, is enabling an entirely autonomous generation of parts and is a major contribution to all powder-based additive manufacturing technologies. Moreover, it makes powder-based AM independent of gravitational forces, which will facilitate crafting items in space from a variety of powdery materials. KW - Additive manufacturing KW - Powder bed PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314244 DO - https://doi.org/10.1155/2014/491581 SN - 1687-8132 SN - 1687-8140 N1 - Geburtsname von Wirth, Cynthia: Gomes, C. M. - Birth name of Wirth, Cynthia: Gomes, C. M. VL - 2014 SP - 491581-1 - 491581-6 PB - Hindawi Publishing Corporation CY - New York, NY ; Cairo AN - OPUS4-31424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nariaki, D. A1 - Lekovic, F. A1 - Homenya, P. A1 - Costa, B. F. O. A1 - Menzel, Michael A1 - Boca, R. A1 - Blumers, M. A1 - Klingelhöfer, G. A1 - Renz, F. T1 - Iron(III) complexes on a dendrimeric basis and various amine core investigated by Mössbauer spectroscopy N2 - Dendrimers of various generations were synthesized by the divergent method. Starting from various amine cores (G0a, G0b, G0c) the generations were built by reaction of the amine with acrylnitrile followed by hydrogenation with DIBAL-H. Treatment with salicylaldehyde creates a fivefold coordination sphere for iron in the molecular periphery. The resulting multinuclear coordination compounds are investigated by Mossbauer spectroscopy. T2 - ICRTP 2014 - International conference on recent trends in physics CY - Indore, India DA - 22.02.2014 PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316331 DO - https://doi.org/10.1088/1742-6596/534/1/012003 SN - 1742-6588 SN - 1742-6596 VL - 534 IS - 1 SP - 012003-1 EP - 012003-8 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-31633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epishin, A.I. A1 - Link, T. A1 - Fedelich, Bernard A1 - Svetlov, I.L. A1 - Golubovskiy, E.R. T1 - Hot isostatic pressing of single-crystal nickel-base superalloys: mechanism of pore closure and effect on mechanical properties N2 - Pore annihilation was investigated in the single-crystal nickel-base superalloy CMSX-4. HIP tests at 1288 °C/103 MPa were interrupted at different times, then the specimens were investigated by TEM, metallography and density measurements. The kinetics of pore annihilation was determined. The pore closure mechanism was identified as plastic deformation on the octahedral slip systems. A model describing the kinetics of pore closure has been developed on the base of crystal plasticity and large strain theory. Mechanical tests with the superalloy CMSX-4 and the Ru-containing superalloy VGM4 showed, that HIP significantly increases the fatigue life at low temperatures but has no effect on creep strength. T2 - Eurosuperalloys 2014 - 2nd European symposium on superalloys and their applications CY - Giens, France DA - 12.05.2014 PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316410 DO - https://doi.org/10.1051/matecconf/20141408003 N1 - Serientitel: MATEC Web of conferences – Series title: MATEC Web of conferences VL - 14 SP - 08003-1 EP - 08003-6 PB - EDP Sciences AN - OPUS4-31641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rades, Steffi A1 - Hodoroaba, Vasile-Dan A1 - Salge, T. A1 - Wirth, Thomas A1 - Lobera, M.P. A1 - Labrador, R.H. A1 - Natte, Kishore A1 - Behnke, Thomas A1 - Gross, Thomas A1 - Unger, Wolfgang T1 - High-resolution imaging with SEM/T-SEM, EDX and SAM as a combined methodical approach for morphological and elemental analyses of single engineered nanoparticles N2 - The combination of complementary characterization techniques such as SEM (Scanning Electron Microscopy), T-SEM (Scanning Electron Microscopy in Transmission Mode), EDX (Energy Dispersive X-ray Spectroscopy) and SAM (Scanning Auger Microscopy) has been proven to be a powerful and relatively quick characterization strategy for comprehensive morphological and chemical characterization of individual silica and titania nanoparticles. The selected “real life” test materials, silica and titania, are listed in the OECD guidance manual as representative examples because they are often used as commercial nanomaterials. Imaging by high resolution SEM and in the transmission mode by T-SEM allows almost simultaneous surface and in-depth inspection of the same particle using the same instrument. EDX and SAM enable the chemical characterization of bulk and surface of individual nanoparticles. The core–shell properties of silica based materials are addressed as well. Titania nominally coated by silane purchased from an industrial source has been found to be inhomogeneous in terms of chemical composition. KW - surface and in-depth inspection KW - silica nanoparticles KW - titania nanoparticles PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316296 DO - https://doi.org/10.1039/c4ra05092d SN - 2046-2069 VL - 4 IS - 91 SP - 49577 EP - 49587 PB - RSC Publishing CY - London AN - OPUS4-31629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - The tribological and mechanical properties of niobium carbides (NbC) bonded with cobalt of Fe3Al N2 - The tribological and mechanical properties of niobium carbide bonded with 8 vol.-% (NbC-8Co), 12 vol.-% of cobalt (NbC-12Co) or 12 vol.-% of Fe3Al (NbC-12Fe3Al) are presented. Rotating discs made of metal-bonded niobium carbide were mated against alumina (99.7%) under unlubricated (dry) unidirectional sliding tests (0.1 m/s to 12.0 m/s; 22 °C and 400 C) as well as in oscillation tests (f=20 Hz, Δx=0.2 mm, 2/50/98% rel. humidity, n=105/106 cycles). Microstructure and phase compositions were determined as well. The tribological data obtained were benchmarked with different ceramics, cermets, hard metals and thermally sprayed coatings, where NbC bonded with 8% and 12% Co presented above 7 m/s the lowest wear rates so far in such a benchmark. Binderless NbC (HP-NbC1) and the metal-bonded NbCs exhibited low wear rates under dry sliding associated with P·V high load carrying capacities. NbC-based hard metal bonded with 12 vol.-% of Fe3Al resulted in a higher hardness level than for 12 vol.-% cobalt. The tribological profile established revealed a strong position of NbC-bearing materials under tribological considerations and for closed tribosystems against established reference tribo-couples. KW - Sliding KW - Ceramic KW - Oscillation KW - Strength KW - Modulus KW - High temperatures KW - Friction KW - Wear KW - NbC KW - Niobium carbide KW - Cobalt KW - Fe3Al KW - Hard metal PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316129 DO - https://doi.org/10.1016/j.wear.2014.09.007 SN - 0043-1648 VL - 321 SP - 1 EP - 7 PB - Elsevier CY - Amsterdam AN - OPUS4-31612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Dohse, Elmar A1 - Bartusch, Jürgen A1 - Köppe, Enrico A1 - Kreutzbruck, Marc A1 - Hillger, W. A1 - Amos, J. M. T1 - Ultrasonic testing of adhesively bonded joints using air-coupled cellular polypropylene transducers N2 - In air-coupled ultrasonic testing, the impedance mismatch between the transducer and the air is commonly being solved by adding matching layers to composite transducers. To avoid the difficult technological procedure regarding matching layers, some new piezoelectric materials have been proposed. Most promising are ferroelectrets, which are charged cellular polymers, having ferroelectric and consequently piezoelectric properties. In particular, the extreme softness of cellular polypropylene (cPP) leads to a high piezoelectric constant and to a good impedance match with the air, making matching layers redundant. Its elasticity modulus below 1 MPa causes an additional effect not observed with common piezoelectric materials: that is the electrostrictive effect, here defined as the thickness change due to the attractive force between the transducer electrodes. This effect exceeds the piezoelectric effect at excitation voltages over 1 kV. The extreme softness of cPP leads also to high flexibility, enabling easy focusing by bending the transducer. We have developed air-coupled ultrasonic transducers based on cPP. This includes the electrical matching networks for the transmitter and for the receiver. The transmitter is excited with voltages up to 2.5 kV, so that the electrostrictive effect dominates, leading to sound pressure around 145dB at the transducer surface. These transducers have been applied for testing carbon-fiber-reinforced polymer plates, adhesive joints and other composite structures. Here we report about ultrasonic transmission of two types of adhesive joints. The first one is multi-layer aluminium components with some artificial disbonds, which are common in aerospace industry, and the second one is an aluminium-steel joint with polyurethane adhesive, which is used in automotive industry. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Air-coupled KW - Ultrasonic testing KW - Ferroelectret KW - Cellular polypropylene KW - Transducer KW - Adhesive joint PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317204 SN - 978-80-214-5018-9 SP - 1 EP - 8 PB - Brno University of Technology AN - OPUS4-31720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schoknecht, Ute A1 - Kalbe, Ute A1 - Van Zomeren, A. A1 - Hjelmar, O. T1 - Laboratory leaching tests on treated wood according to different harmonised test procedures N2 - -Background- Laboratory leaching tests on treated wood were performed during a European robustness study in the framework of the validation of a tank leaching test procedure that has been proposed for construction products in order to determine the potential release of dangerous substances which can be transferred to soil and groundwater. The release of substances has to be determined also for materials treated with biocidal products according to the requirements of the European Biocidal Products Regulation. A similar leaching test procedure was already harmonised for treated wood for this purpose. Both test procedures were applied in parallel to wood treated with the same preservative to investigate whether the results of these tests can replace each other. Additional experiments were performed to further investigate unexpected effects of L/A ratio on leaching of copper and duration of storage of treated test specimens. -Results- Both procedures generate similar results concerning cumulative emissions of tebuconazole, copper, dissolved organic carbon and total nitrogen. The emission rates with time are in comparable ranges for both leaching protocols. Emissions of copper increased with decreasing L/A ratios. Strong correlation of copper concentrations and dissolved organic carbon as well as total nitrogen concentrations in eluates indicates that this observation is caused by co-elution of copper with organic substances. Duration of storage of treated test specimens affected emissions for the investigated wood preservative. -Conclusions- Based on these findings, results from both test procedures can be used to describe leaching characteristics and avoid double testing of treated wood to fulfil the requirements of the European regulations for either biocides or construction products. Leaching of substances from treated wood is a complex process that depends on its chemical composition and ageing processes. KW - Construction products KW - Biocidal product KW - Emission KW - Leaching KW - Tank leaching test KW - Treated wood KW - European regulation PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317320 UR - http://www.enveurope.com/content/26/1/25 SN - 2190-4715 SN - 2190-4707 VL - 26 SP - 25, 1 EP - 10 PB - Springer CY - Berlin ; Heidelberg AN - OPUS4-31732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stoch, P. A1 - Szczerba, Wojciech A1 - Bodnar, W. A1 - Ciecinska, M. A1 - Stoch, A. A1 - Burkel, E. T1 - Structural properties of iron-phosphate glasses: spectroscopic studies and ab initio simulations N2 - Vitrification is the most effective method for the immobilization of hazardous waste by incorporating toxic elements into a glass structure. Iron phosphate glasses are presently being considered as matrices for the storage of radioactive waste, even of those which cannot be vitrified using conventional borosilicate waste glass. In this study, a structural model of 60P2O5–40Fe2O3 glass is proposed. The model is based on the crystal structure of FePO4 which is composed of [FeO4][PO4] tetrahedral rings. The rings are optimized using the DFT method and the obtained theoretical FTIR and Raman spectra are being compared with their experimental counterparts. Moreover, the proposed model is in very good agreement with X-ray absorption fine structure spectroscopy (XANES/EXAFS) and Mössbauer spectroscopy measurements. According to the calculations the Fe3+ is in tetrahedral and five-fold coordination. The maximal predicted load of waste constituents into the glass without rebuilding of the structure is 30 mol%. Below this content, waste constituents balance the charge of [FeO4]- tetrahedra which leads to their strong bonding to the glass resulting in an increase of the chemical durability, transformation and melting temperatures and density. KW - Glass KW - Iron KW - DFT simulations KW - Mössbauer spectroscopy KW - XANES/EXAFS KW - FTIR spectroscopy KW - Raman spectroscopy KW - Coordination PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317351 DO - https://doi.org/10.1039/c4cp03113j SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 37 SP - 19917 EP - 19927 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-31735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kunte, Hans-Jörg A1 - Lentzen, G. A1 - Galinski, E. T1 - Industrial production of the cell protectant ectoine: protection mechanisms, processes, and products N2 - Bacteria, Archaea and Eukarya can adapt to Saline environments by accumulating compatible solutes in order to maintain an osmotic equilibrium. Compatible solutes are of diverse chemical structure (sugars, polyols, amino acid derivatives) and are beneficial for bacterial cells not only as osmoregulatory solutes, but also as protectants of proteins by mitigating detrimental effects of freezing, drying and high temperatures. The aspartate derivative ectoine is a wide spread compatible solute in Bacteria and possesses additional protective properties compared with other compatible solutes, and stabilizes even whole cells against stresses such as UV radiation or cytotoxins. The protective properties of ectoine for proteins can be explained by its strong (kosmotropic) interaction with water and subsequent exclusion from Protein surface, the decrease of the solubility of the peptide backbone and the strengthening of intramolecular hydrogen bonds (secondary structures). The stabilizing and UV-protective properties of ectoine attracted industry, which saw the potential to market ectoine as a novel active component in health care products and cosmetics. In joint efforts of industry and research large-scale fermentation procedures have been developed with the halophilic bacterium Halomonas elongata used as a producer strain. The two key technologies that allow for the annual production of ectoine on a scale of tons are the bacterial milking procedure and the development and application of ectoine-excreting mutants (“leaky” mutant). The details of these two procedures including the strain development and Fermentation processes will be introduced and current and future applications of ectoine will be discussed. KW - Bacterial milking KW - Batch fermentation KW - Continuous culture KW - Ectoine excretion KW - Hofmeister effect KW - Kosmotrope KW - “leaky” mutant KW - Osmophobic effect KW - Protein protection KW - Preferential exclusion PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376805 DO - https://doi.org/10.2174/22115501113026660037 SN - 2211-551X VL - 3 IS - 1 SP - 10 EP - 25 PB - Bentham Science AN - OPUS4-37680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zscherpel, Uwe A1 - Schumacher, David A1 - Redmer, Bernhard A1 - Ewert, Uwe A1 - Ullberg, C. A1 - Weber, N. A1 - Pantsar, T. T1 - Digital radiology with photon counting detectors N2 - The progress in X-ray detector electronics (sensitivity and speed) allows meanwhile fast single photon detection by a matrix detector. Combined photon counting and energy discrimination is implemented in the electronic circuit of each detector pixel. The company XCounter developed detectors based on CdTe single crystals, which can be tiled to larger areas and have a pixel size of 100ìm. The largest area available in beginning of 2014 is 50x75 mm². These detectors have very promising properties, which make them very suitable for NDT applications: 1. A CdTe attenuation layer of 750 µm thickness allows efficient X-ray detection up to ca. 300 keV. In counting mode only photon noise is important; no other detector noise sources need to be considered. There is no Offset signal without radiation. 2. Each of the detector pixels has two energy thresholds. These can be used for dual energy imaging for materials separation. Also the suppression of scattered radiation by energy thresholding will improve the image contrast sensitivity. First experiments will be presented which demonstrate the advantages of this new detector technology over the conventional charge integrating detectors. A challenge is the development of a modified detector calibration procedure, which becomes critical at longer exposure times. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Materials characterization KW - Radiographic testing (RT) KW - Digital detector array KW - Photo counting KW - Image quality KW - Calibration KW - Dual-energy KW - Energy discrimination KW - Digital radiology KW - Detectors PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323063 UR - https://www.ndt.net/?id=16709 SN - 1435-4934 N1 - Geburtsname von Schumacher, David: Walter, D. - Birth name of Schumacher, David: Walter, D. VL - 19 IS - 12 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-32306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schumm, A. A1 - Martin, E. A1 - Beaumont, M. A1 - Ewert, Uwe A1 - Kolkoori, Sanjeevareddy A1 - Zscherpel, Uwe A1 - Wrobel, Norma A1 - Redmer, Bernhard T1 - A comparative study on the performance of digital detector systems for high energy applications N2 - For cast components reaching or exceeding total material thicknesses of 150mm, high energy sources such as linear accelerators or Betatrons are required in order to obtain reasonable exposure times. In this study, the performance of digital detector systems, involving imaging plates (IP) and digital detector arrays (DDA), was evaluated with respect to the testing class B requirements as formulated in the standard EN ISO 17636-2. As a reference, traditional radiographic film and a Cobalt-60 source was used. With film exposures, testing class B was achieved with Co-60 and Betatron (7.5 MV) at longer exposure times. The preliminary results show that the testing class B was not obtained with the examined digital detector arrays (DDA) and the high resolution imaging plates (IP) , even at 40, 60 and 80 minutes exposure time with a 7.5 MV Betatron. Class A was achieved using high resolution imaging plates with optimized metal filters between object and IPs and a high resolution DDA with intermediate Cu filters. Class A was also achieved applying a DDA with lower basic spatial resolution than required by Table B.13 of EN ISO 17636-2, but using the compensation principle as described in this standard. The next generation of digital detector arrays might potentially be able to obtain class B performance with the expected spatial resolution and sensitivity improvements. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Radiography KW - Image quality KW - Betatron KW - Digital detector array (DDA) KW - Casting KW - Standards KW - High energy radiography KW - Comparison of detectors KW - Steel weldment PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323075 UR - https://www.ndt.net/?id=16394 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 6 PB - NDT.net CY - Kirchwald AN - OPUS4-32307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe T1 - Minimum requirements for digital radiography equipment and measurement procedures by different industries and standard organizations N2 - The digital photography has almost completely substituted the film photography. The film replacement is also fast progressing in medical X-ray radiography. This process is slower in NDT and especially in Europe. Reasons for the hesitating change to digital radiography (RT-D) in NDT are the necessary time for adoption of standards and the conservative request for film RT by auditors and NDT managers for applications in large plants and at construction areas. The fast serial inspection for small castings is already almost completely dominated by RT-D due to the cost effective short exposure and interpretation times. Standards were developed in parallel at CEN, ISO, ASTM and ASME. Unfortunately, the standard practices are different and the requirements on image quality and useable hardware are different too. The first standard series on Computed Radiography were developed and published by CEN and ASTM in 2005. Harmonized classification and qualification standards are available but the published practices are different. ASTM has developed the first standards for application of Digital Detector Arrays (DDA) in 2010. The first digital RT ISO standard practice is ISO 17636-2 (2013), which describes the practice for application of DDAs and Imaging Plates for weld inspection. At the first time this standard provides requirements for the selection of suitable hardware. Minimum image quality requirements are specified in analogy to film radiography and 3 Compensation Principles are defined to enable the application of a wider range of digital detectors. A comparison of the different international digital RT standards is given and first experiences with ISO 17636-2 are discussed. New standards on RT wall thickness and corrosion measurements (EN 16407, film and digital) have been developed recently. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - NDT KW - X-Ray KW - Digital detectors KW - Standards KW - Radiographic procedures KW - Unsharpness KW - Basic spatial resolution KW - Requirements KW - Digital industrial radiology PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323081 UR - https://www.ndt.net/?id=16708 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 18 PB - NDT.net CY - Kirchwald AN - OPUS4-32308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - New X-ray backscatter imaging technique for nondestructive testing of aerospace components N2 - Critical parts in aircraft manufacturing such as stringers are very commonly used in modern aircraft structures to resist the compressive loads caused by the aerodynamic effects. They are generally made-up of thin aluminium (Al) metal sheets and are one of the key components in the aircraft wings. Any defects in the stringer leads to weakening of the stiffness of the whole wing structure and consequently, failures may occur. Hence, the structural integrity of the stringers should be evaluated using reliable non-destructive testing (NDT) methods. Due to the complex shaped structure of the stringer, the one-sided access NDT method such as X-ray backscatter technique is more preferable for the non-destructive imaging. In this paper, we present a new X-ray backscatter technique to image the internal sections of the stringer with only a single-sided access. The whole object was inspected by changing the viewing direction of the X-ray backscatter camera. For the first time, the X-ray backscatter measurements were conducted using high-energy (> 0.5MeV) X-rays and proved the applicability of the present technique to inspect thick carbon-fiber laminated components. In order to improve the inspection time and image quality of the backscatter image, we used high-resolution (180ìm) digital detector arrays (DDAs). At the end, important applications of the presented X-ray backscatter technique to the aerospace industry are discussed. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - X-ray backscatter imaging KW - Twisted-slit collimator KW - NDT KW - Digital detector array (DDA) KW - Stringer KW - Aerospace applications PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322376 UR - https://www.ndt.net/?id=16431 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-32237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Deresch, Andreas A1 - Redmer, Bernhard A1 - Ewert, Uwe T1 - Dual high-energy X-ray digital radiography for material discrimination in cargo containers N2 - In this contribution, we present a dual high-energy X-ray imaging technique for cargo container inspection using the 'spectral high-energy X-ray attenuation method'. This method is based on attenuation of continuous highenergy spectra. The developed experimental technique consists of a betatron as high-energy (up to 7.5 MeV) X-ray source and a matrix detector with high spatial resolution (400 ìm) for digital X-ray imaging. In order to evaluate the material discrimination capability using dual high-energy X-ray imaging, a test specimen is proposed, comprising step wedges of different low and high atomic number (Z) materials. The selected X-ray spectra for the dual-energy experiments correspond to 3 MV and 7.5 MV acceleration potential of the betatron. We evaluated the ratio between low- and high-energy X-ray attenuation coefficients quantitatively based on simulated poly-energetic high-energy X-ray source spectra and the detector sensitivity using the 'analytical Radiographic Testing inspection simulation tool' (aRTist) developed at BAM. The simulated effective attenuation coefficients are compared with corresponding experimental results in order to establish a method for identification of low- and high-Z materials in the container. Finally, important applications of the proposed technique in the context of aviation security are discussed. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Digital radiography KW - NDT KW - High-energy X-ray imaging KW - Betatron KW - Digital detector array (DDA) KW - Container inspection KW - Material discrimination KW - Effective attenuation coefficient PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322394 UR - https://www.ndt.net/?id=16430 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 10 PB - NDT.net CY - Kirchwald AN - OPUS4-32239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolf, S. A1 - McMahon, Dino Peter A1 - Lim, K.S. A1 - Pull, C.D. A1 - Clark, S.J. A1 - Paxton, R.J. A1 - Osborne, J.L. T1 - So near and yet so far: harmonic radar reveals reduced homing ability of Nosema infected honeybees N2 - Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed. PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-328827 DO - https://doi.org/10.1371/journal.pone.0103989 SN - 1932-6203 VL - 9 IS - 8 SP - e103989, 1 EP - 15 PB - PubMed Central AN - OPUS4-32882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Feldmann, Rüdiger A1 - Zoёga, Andreas A1 - Milmann, Boris A1 - Krause, Martin T1 - Ortung tiefliegender Bewehrung durch Ultraschall mit bildgebender Phasenauswertung N2 - Die Ortung von schlaffer Bewehrung in Beton erfolgt routinemäßig mit bildgebenden Radar- oder Wirbelstromverfahren. Die Anwendung dieser Verfahren ist aber begrenzt, wenn es sich um die Ortung tiefliegender Bewehrung (ab ca. 30 cm) oder um jungen Beton handelt. Grund ist die Schwächung der Radarpulse durch oberflächennahe Bewehrung oder durch die Betonfeuchte. Das bildgebende Ultraschallechoverfahren bietet den Vorteil, dass die Ultraschallpulse in diesen Fällen eine wesentlich höhere Eindringtiefe erreichen. Im vorliegenden Beitrag wird eine Fallstudie vorgestellt, bei der mehrlagig eingebrachte Bewehrungseisen in einer nur einseitig zugänglichen 60 cm dicken Betonplatte geortet werden sollten, um eine Kernbohrung ohne Verkanten der Bohrkrone durchzuführen. Zur Ortung der Bewehrung wurde das Ultraschallechoverfahren mitScherwellen der Mittenfrequenz 50 kHz mit einem automatisch arbeitenden Bauwerksscanner eingesetzt. Aus den flächig aufgenommenen Messdaten wurde mit der Rekonstruktionsrechnung nach dem Prinzip der synthetischen Apertur (SAFT, Synthetic Aperture Focusing Technique) die Position der Bewehrungseisen bildhaft ortsgenau dargestellt. Dies gelingt mit einer Auswertungsoption, bei der die Phase der reflektierten Ultraschallpulse ermittelt und farbcodiert dargestellt wird (Phasenauswertung). Damit lassen sich Reflexionen der Bewehrung eindeutig von eventuellen Fehlstellen oder Rückwandechos unterscheiden. T2 - Fachtagung Bauwerksdiagnose 2014 CY - Berlin, Germany DA - 13.02.2014 KW - Ultraschallecho-Verfahren KW - SAFT KW - Bewehrung KW - Beton KW - Abbildungsverfahren PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351056 UR - https://www.ndt.net/?id=15885 SN - 1435-4934 VL - 19 IS - 8 SP - 1 EP - 11 PB - NDT.net CY - Kirchwald AN - OPUS4-35105 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brackrock, Daniel A1 - Recknagel, Christoph A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Untersuchungen von Glas-Metall Klebverbindungen mit Hilfe von Ultraschall N2 - Klebverbindungen im modernen Hochbau können helfen, innovative ästhetische Bedürfnisse im Fassadenbau umzusetzen, technologische Verbesserungen zu erreichen, aber auch die Wechselwirkung von Gebäuden mit der Umwelt unter energetischen Aspekten zu optimieren. Aufgrund der hohen sicherheitstechnischen Bedeutung gibt es hohe Anforderungen an die Leistungsfähigkeit, Dauerhaftigkeit und die Gütesicherheit. Mit einer zerstörungsfreien praxistauglichen Prüftechnik, die eine sichere Überprüfung der Integrität von Glas-Metall Klebverbindungen im Ingenieurhochbau gewährleistet, kann sowohl ein wichtiger Beitrag zur Qualitätssicherung bei der Herstellung von Fassadenelementen aber auch bei der späteren Bauwerksüberwachung im Verlauf der Nutzungsdauer geleistet werden. Für eine Beurteilung der Qualität der Verbundfuge (z.B. bezgl. Standsicherheit) sind dabei Aussagen zur Homogenität der Verbundfuge, zum adhäsiven und kohäsiven Verbundverhalten gefordert. Hierzu besteht aktuell insbesondere Bedarf an zerstörungsfreien praxisgerechten, hoch ortsauflösenden und möglichst bildgebenden Untersuchungsverfahren. Es wird mit einem Matrixarray und mit konventionellen Winkelprüfköpfen eine Prüftechnik vorgestellt, mit der die Wechselwirkung zwischen Ultraschallwelle und Fehlstelle in der Klebefuge untersucht wird. Hierbei ist das erste Untersuchungsziel, mit einer angepassten Ultraschall-Prüftechnik mögliche Inhomogenitäten oder Schädigungsstellen in der geklebten Glas-Metall Verbindung zu detektieren. Über diese qualitativen Aussagen hinaus werden weiterführende Informationen über die flächenhafte Ausdehnung und den Ort einer mangelnden Klebung ermittelt. Dazu werden die Messwerte zusammen mit den Positionen des Ultraschallprüfkopfs aufgezeichnet. Mit Hilfe einer bildhaften Auswertung der gemessenen Ultraschallechos in Abhängigkeit vom Prüfkopfort werden die Möglichkeiten einer detaillierten Integritätsanalyse der Glas-Metall Klebschicht dargestellt. In diesem Beitrag werden experimentelle Prüfergebnisse vorgestellt, die im Sinne einer Verfahrensvalidierung an einem speziellen Beispielprobekörper zur Nachstellung einer SSG-Verglasung (ermittelt wurden und die Detektion fehlerhafter Klebestellen in einer Glas-Metall-Klebverbindung zum Ziel haben. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-331181 UR - https://www.ndt.net/?id=17428 SN - 978-3-940283-61-0 VL - 148 SP - 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-33118 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stoycheva, V. A1 - Goering, Harald A1 - Wolff, Dietmar A1 - Herzog, M. T1 - Bestimmung der Kohäsionsenergie- und Vernetzungsdichte von Polymeren mit Hilfe von Quellungsmessungen N2 - Bei der Abschätzung der Beständigkeit von Kunststoffen gegenüber niedermolekularen Flüssigkeiten ist die Kohäsionsenergiedichte CED ein wichtiger Parameter auf molekularer Ebene. Die Vernetzungsdichte ν eines polymeren Festkörpers bildet hierbei einen bedeutsamen Kennwert, der darüber hinaus neben der Löslichkeit wichtige Eigenschaften wie thermische Stabilität und Steifigkeit des Materials charakterisiert. Für die experimentelle Bestimmung von CED und ν eignet sich die Untersuchung des Quellverhaltens in unterschiedlichen Lösungsmitteln. Es werden zwei Messmethoden miteinander verglichen und die Ergebnisse unter Berücksichtigung des molekularen Aufbaus von Proben aus Polyurethan (PU) und hochmolekularem – (HMWPE) und ultrahochmolekularem Polyethylen (UHMWPE) diskutiert. Zum Verständnis des Quellverhaltens dieser Polymerproben in niedermolekularen Lösungsmitteln werden neben den Messergebnissen Literaturdaten zu Grunde gelegt. KW - Quellungsmessung KW - Kohäsionsenergie KW - Venetzungsdichte PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:526-opus4-3372 SN - 0949-8214 VL - 18 SP - 77 EP - 84 PB - News & Media CY - Berlin AN - OPUS4-32411 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -