TY - JOUR A1 - Nguyen, Thi Yen A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Direct evidence of polyamorphism in paracetamol N2 - While polymorphism is a common phenomenon in the crystallization processes of organic compounds, polyamorphism has gained importance only recently. Using sophisticated sample environments and applying in situ scattering methods and vibrational spectroscopy, the complete crystallization process of organic compounds from solution can be traced and characterized. Diffuse scattering from amorphous intermediates can be investigated by analyzing the atomic pair distribution function (PDF) to gain further insights into molecular pre-orientation. The crystallization behavior of paracetamol was studied exemplarily under defined, surface-free conditions. Based on the choice of the solvent, the formation of different polymorphs is promoted. The thermodynamically stable form I and the metastable orthorhombic form II could be isolated in pure form directly from solution. For both polymorphs, the crystallization from solution proceeds via a distinct amorphous precursor phase. PDF analyses of these different amorphous states indicate a specific pre-orientation of the analyte molecules introduced by the solvent. The resulting crystalline polymorph is already imprinted in these proto-crystalline precursors. Direct experimental evidence for the polyamorphism of paracetamol is provided. PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351366 DO - https://doi.org/10.1039/C5CE01583A SN - 1466-8033 VL - 17 IS - 47 SP - 9029 EP - 9036 PB - Royal Society of Chemistry CY - London, UK AN - OPUS4-35136 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Bellon, Carsten A1 - Hohendorf, Stefan A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Nusser, A. A1 - Freitag, M. A1 - Bücherl, T. A1 - Bar, D. A1 - Mor, I. A1 - Tamin, N. A1 - Weiss-Babai, R. A1 - Bromberger, B. A1 - Dangendorf, V. A1 - Tittelmeier, K. T1 - Computed tomography with X-rays and fast neutrons for restoration of wooden artwork N2 - The objects of this investigation were sculptures taken from a ca. three hundred years old baroque epitaph of a church in Tonning, a town in Northern Germany. Around 1900 it was found in a disastrous state heavily damaged by wood-worm. At that time, the whole artwork was treated with the tar extract carbolineum as a remedy. Nowadays, this substance has been identified as carcinogenic, and its presence can be perceived by its stench and visually at certain spots on the surface where it has penetrated the covering paint. A gold-painted sculpture of a massive wooden skull was interrogated with X-rays and fast neutrons to investigate the internal distribution of the carbolineum. The X-ray tomography, with its excellent spatial resolution revealed galleries left over from the worm infestation in the outer areas and cracks in the central region. The golden color coating appeared as a thick and dense layer. In comparison the tomography with fast neutrons, though being of lower resolution and yet unresolved artefacts revealed sections of slightly different densities in the bulk of the wood. These differences we attribute to the differences in the distribution of the impregnant in the wood, visible due to its higher hydrogen content making it less transparent for neutrons. T2 - WCNR-10 - 10th World conference on neutron radiography CY - Grindelwald, Switzerland DA - 05.10.2014 KW - Computed tomography KW - Neutron radiology KW - Conservation of wooden artwork PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323050 DO - https://doi.org/10.1016/j.phpro.2015.07.066 SN - 1875-3892 VL - 69 SP - 472 EP - 477 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Bischof, Eik A1 - Taffe, A. T1 - Multi-sensor investigation of concrete moisture using ultrasound, radar and microwave N2 - Moisture and salt loads of concrete can significantly change its microstructure and consequently lead to chemical and mechanical degradation. However, the non-destructive investigation of moisture and salt present in concrete is still difficult. In order to address and compare the sensitivity of different methods concrete samples with different pore systems realized by varying the w/z ratios have been fabricated. The focus of this study was put on the analysis of ultrasonic long and trans waves measured on the surface and in transmission mode. The results show clear dependencies of all applied methods. With the radar and microwave methods predominantly changes in the concrete moisture could be detected, whereas the different pore systems were not observed to alter the signals. In contrast for the ultrasound method also the ongoing hydration as well as the nature of the pore system strongly influenced the signals. As a consequence in a subsequent drying experiment it was also tried to delineate the effects of moisture and hydration. All specimens have been re-saturated under pressure and the drying experiment was repeated using the same multi-sensor approach. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Concrete KW - Moisture KW - Non-destructive testing KW - Ultrasound KW - Radar KW - Velocities KW - Microwave KW - Multi-sensor approach PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347612 UR - http://www.ndt.net/?id=18322 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Feldmann, Rüdiger T1 - Comparison of non-destructive moisture measurement methods on cement and calcium sulphate based screed samples N2 - Measuring the moisture content of floor screeds is usually done with minor destructive testing methods like Darr drying or the Calcium Carbid (CM) method. These require small samples, deliver only punctual information and still have proven not to be very reliable. Hence, a study has been made using the standard destructive tests as well as a suite of non-destructive testing methods working out their use for moisture determination. In this study five partners from research institutes and industry worked together and intensively researched different technologies. The main focus was put on the varying sensitivity of the measuring techniques in different moisture ranges. Especially for low moisture contents ( or ‘critical’ moisture contents when the screed is dry enough to be covered with the final floor finish), several commercial devices including the most commonly used CM-method failed to determine the correct moisture content for cementitious samples. Hence the need for more accurate, if possible non-destructive methods is high, taking also into account that the chemistry (and physical properties) of screeds may vary strongly depending on their origin and purpose. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Screed KW - Moisture KW - Non-destructive testing KW - Radar KW - Capacitive methods KW - Resistivity KW - Multi-sensor KW - Electrics KW - Monitoring PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347602 UR - http://www.ndt.net/?id=18368 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Martin A1 - Mauke, R. A1 - Effner, Ute A1 - Milmann, Boris A1 - Völker, Christoph A1 - Wiggenhauser, Herbert T1 - Ultrasonic testing of a sealing construction made of salt concrete in an underground disposal facility for radioactive waste N2 - For the closure of radioactive waste disposal facilities engineered barriers- so called “drift seals” are used. The purpose of these barriers is to constrain the possible infiltration of brine and to prevent the migration of radionuclides into the biosphere. In a rock salt mine a large scale in-situ experiment of a sealing construction made of salt concrete was set up to prove the technical feasibility and operability of such barriers. In order to investigate the integrity of this structure, non-destructive ultrasonic measurements were carried out. Therefore two different methods were applied at the front side of the test-barrier: 1 Reflection measurements from boreholes 2 Ultrasonic imaging by means of scanning ultrasonic echo methods This extended abstract is a short version of an article to be published in a special edition of ASCE Journal that will briefly describe the sealing construction, the application of the non-destructive ultrasonic measurement methods and their adaptation to the onsite conditions -as well as parts of the obtained results. From this a concept for the systematic investigation of possible contribution of ultrasonic methods for quality assurance of sealing structures may be deduced. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 2015-09-15 KW - Ultrasonic reflection measurement KW - Dry contact transducers in boreholes KW - Interface salt-concrete / rock salt KW - Ultrasonic imaging of internal reflectors PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346203 UR - http://www.ndt.net/?id=18304 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grothe, Sven T1 - Ultrasonic signal evaluation used to detect temperature changes in a concrete specimen caused by a heating system N2 - Ultrasonic measurement evaluation methods have been proven to be effective for detection of subtle changes, caused by temperature, load or moisture. To detect and localize temperature changes, a concrete block of 4 × 5 × 0.8 m3, including a heating cartridge and multiple temperature sensors, has been set up to change the temperature and monitor the temperature distribution in a certain area inside the specimen. An ultrasonic monitoring system with 40 ultrasonic sensors (20 transmitters, 20 receivers, 25 kHz central frequency) has been implemented on the specimen. Data from 400 sensor combinations was collected over the whole period of the experiment in an interval of 30 minutes. Quantitative methods (CodaWave Interferometry and Time of Flight method) were used to evaluate the changes in ultrasonic travel-time caused by the heating period, when the cartridge was active, and the cooling period after turning off the cartridge. Furthermore the travel-time changes from all 400 sensor combinations were used to locate the heating cartridge. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346387 UR - http://www.ndt.net/?id=18336 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zheng, H. A1 - Kappatos, V. A1 - Niederleithinger, Ernst A1 - Ertel, Jens-Peter A1 - Grohmann, Maria A1 - Selcuk, C. A1 - Gan, T.-H. T1 - Defect detection in concrete pile using impulse response measurements with sine sweep excitations N2 - For pile integrity inspection, a low cost and portable shaker was used to create the sine sweep signal for pile excitation. The impulse response function, calculated by the deconvolution of pile response from the sine sweep excitation, was proposed to identify the echoes in the piles due to the pile’s impedance changes. The proposed methodology has been evaluated and validated both numerically and experimentally. Based on the results from the simulations and experiments, it was found that the impulse response measurement with sine sweep excitation could be an effective tool to detect the echoes of the pile toe and the defects in the pile. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Impulse response function KW - Sine sweep excitation KW - Pile integrity KW - Damage detection PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347157 SN - 1435-4934 SP - 1 EP - 4 PB - Technische Universität Berlin / Bundesanstalt für Materialforschung und -prüfung AN - OPUS4-34715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klykov, Oleg A1 - Weller, Michael G. T1 - Quantification of N-hydroxysuccinimide and N-hydroxysulfosuccinimide by hydrophilic interaction chromatography (HILIC) N2 - N-Hydroxysuccinimide (NHS) esters are the most important activated esters used in many different bioconjugation techniques, such as protein labelling by fluorescent dyes and enzymes, surface activation of chromatographic supports, microbeads, nanoparticles, and microarray slides, and also in the chemical synthesis of peptides. Usually, reactions with NHS esters are very reliable and of high yield, however, the compounds are sensitive to air moisture and water traces in solvents. Therefore, the quantification of NHS would be a very helpful approach to identify reagent impurities or degradation of stored NHS esters. No robust and sensitive method for the detection of NHS (or the more hydrophilic sulfo-NHS) has been reported yet. Here, a chromatographic method based on HILIC conditions and UV detection is presented, reaching a detection limit of about 1 mg L-1, which should be sensitive enough for most of the applications mentioned above. Exemplarily, the hydrolytic degradation of a biotin-NHS ester and a purity check of a fluorescent dye NHS ester are shown. An important advantage of this approach is its universality, since not the structurally variable ester compound is monitored, but the constant degradation product NHS or sulfo-NHS, which avoids the necessity to optimize the separation conditions and facilitates calibration considerably. KW - NHS KW - Sulfo-NHS KW - NHS-Ester KW - Qualitätskontrolle KW - Reinheitsbestimmung KW - HPLC PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337833 DO - https://doi.org/10.1039/c5ay00042d SN - 1759-9660 SN - 1759-9679 VL - 7 IS - 15 SP - 6443 EP - 6448 PB - RSC Publ. CY - Cambridge AN - OPUS4-33783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Carl, Peter A1 - Schneider, Rudolf T1 - Optimization and evaluation of a hapten microarray using chemometric methods N2 - The demands for the assessment of water quality are increasing steadily, making it necessary to routinely monitor multiple contaminants in water samples. For this application a hapten microarray was developed. In order to reach the required low detection limits a design of experiments (DoE) approach was used to optimize the assay performance. Here we show that a Box-Behnken design plan is an adequate choice for the straightforward exploration of hapten microarray assay parameters. For both read-out systems studied (fluorophore-labelled detection antibodies or enzymatic signal development followed by reflectometric scan, respectively), it was possible to significantly extend the measurement ranges. Furthermore, it could be shown that multivariate data analysis, here partial least squares regression (PLS), can improve the prediction accuracy of 'unknown' samples when used as calibration model, compared to classical, univariate data evaluation methods. KW - Koffein KW - Caffeine KW - Proteine microarray KW - Design of experiments KW - Multivariate data analysis KW - Partial least squares regression KW - Small molecule detection KW - Microarray KW - Immunoarray KW - Immunoassay KW - ELISA KW - Chemometrie KW - Chemometrics PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344672 DO - https://doi.org/10.1016/j.proeng.2015.08.684 SN - 1877-7058 VL - 120 SP - 501 EP - 506 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-34467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siebler, Daniel A1 - Rohwetter, Philipp A1 - Brusenbach, R. A1 - Plath, R. T1 - Optical-only detection of partial discharge with fluorescent polymer optical fiber sensors N2 - This paper reflects recent progress in the field of fluorescent polymer optical fiber sensors (F-POF) for partial discharge (PD) detection in high voltage (HV) cable accessories using optical-only PD detection by coincidence single photon counting. In experiments with artificial PD sources these sensors show the ability to detect optical emissions from picocoulomb-level PDs in a real-scale model of a translucent high voltage cable accessory. False positives (caused by detector noise) are efficiently suppressedwhile maintaining sufficient sensitivity,even when the sensor is located in an unfavorable position. T2 - EUROSENSORS 2015 CY - Freiburg, Germany DA - 06.09.2015 KW - Partial discharge KW - Silicone rubber KW - High voltage cable accessories KW - Polymer optical fiber POF KW - Fluorescence KW - Coincidence PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337881 DO - https://doi.org/10.1016/j.proeng.2015.08.711 SN - 1877-7058 VL - 120 SP - 845 EP - 848 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-33788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -