TY - JOUR
A1 - Li, X.M.
A1 - Li, H.M.
A1 - Zhang, Q.H.
A1 - Lu, X.H.
A1 - Li, S.Q.
A1 - Koch, Matthias
A1 - Polzer, J.
A1 - Hackenber, R.
A1 - Moniruzzaman, M.
A1 - Khan, M.
A1 - Kakoulides, E.
A1 - Pak-Wing, K.
A1 - Richy,
A1 - Chi-Shing, N.
A1 - Lu, T.
A1 - Gui, E.M.
A1 - Cheow, P.S.
A1 - Teo, T.L.
A1 - Rego, E.
A1 - Garrido, B.
A1 - Carvalho, L.
A1 - Leal, R.
A1 - Violante, F.
A1 - Baek, S.Y.
A1 - Lee, S.
A1 - Choi, K.
A1 - Kim, B.
A1 - Bucar-Miklavcic, M.
A1 - Hopley, C.
A1 - Nammoonnoy, J.
A1 - Murray, J.
A1 - Wilson, W.
A1 - Toman, B.
A1 - Itoh, N.
A1 - Gokcen, T.
A1 - Krylov, A.
A1 - Mikheeva, A.
T1 - CCQM-K146 low-polarity analyte in high fat food: benzo a pyrene in olive oil
N2 - The demonstration of competency and equivalence for the assessment of levels of contaminants and nutrients in primary foodstuffs is a priority within the 10-year strategy for the OAWG Track A core comparisons. The measurements are core challenges for reference material producers and providers of calibration Services. This key comparison related to low polarity analytes in a high fat, low protein, low carbohydrate food matrix and Benzo[a]pyrene in edible oil was the model System selected to align with this class within the OAWG strategy. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (Dis). 16 National Metrology Institutions participated in the Track A Key Comparison CCQM-K146 Low-Polarity Analyte in high fat food: Benzo[a]pyrene in Olive Oil. Participants were requested to evaluate the mass fractions, expressed in µg/kg, of Benzo[a]pyrene in the olive oil material. The KCRV was determined from the results of all NMIs/DIs participating in the key comparison that used appropriately validated methods with demonstrated metrological traceability. Different methods such as liquid-liquid extraction, GPC and SPE were applied in the sample pretreatment and HPLC-FLD, HPLC-MS/MS, and GC-MS or GC-MS/MS were applied for detection by the participants. The mass fractions for BaP were in the range of (1.78 to 3.09) µg/kg with Standard uncertainties of (0.026 to 0.54) µg/kg, with corresponding relative Standard uncertainties from 0.9% to 21%. Five labs withdrew their result from the Statistical evaluation of the KCRV for technical reasons. One lab was excluded from the KCRV evaluation, as they did not meet the CIPM metrological traceability requirements. A Hierarchical Bayes option was selected for the KCRV value, which was determined as 2.74 µg/kg with a Standard uncertainty of 0.03 µg/kg. The 10 institutes those were included in the calculation of the consensus KCRV all agreed within their Standard uncertainties. Successful participation in CCQM-K146 demonstrates the measurement capabilities in determining mass fraction of organic compounds, with molecular mass of 100 g/mol to 500 g/mol, having low polarity pKow < -2, in mass fraction range from 0.1 µg/kg to 1000 µg/kg in a high fat, low protein, low carbohydrate food matrix.
KW - Metrology
KW - CCQM
KW - Food
KW - PAH
PY - 2020
DO - https://doi.org/10.1088/0026-1394/57/1a/08017
VL - 57
IS - 1a
SP - 08017
AN - OPUS4-52435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Trimpin, Sarah
A1 - Yenchick, Frank S.
A1 - Lee, Chuping
A1 - Hoang, Khoa
A1 - Pophristic, Milan
A1 - Karki, Santosh
A1 - Marshall, Darrell D.
A1 - Lu, I-Chung
A1 - Lutomski, Corinne A.
A1 - El-Baba, Tarick J.
A1 - Wang, Beixi
A1 - Pagnotti, Vincent S.
A1 - Meher, Anil K.
A1 - Chakrabarty, Shubhashis
A1 - Imperial, Lorelei F.
A1 - Madarshahian, Sara
A1 - Richards, Alicia L.
A1 - Lietz, Christopher B.
A1 - Moreno-Pedraza, Abigail
A1 - Leach, Samantha M.
A1 - Gibson, Stephen C.
A1 - Elia, Efstathios A.
A1 - Thawoos, Shameemah M.
A1 - Woodall, Daniel W.
A1 - Jarois, Dean R.
A1 - Davis, Eric T.J.
A1 - Liao, Guochao
A1 - Muthunayake, Nisansala S.
A1 - Redding, McKenna J.
A1 - Reynolds, Christian A.
A1 - Anthony, Thilani M.
A1 - Vithanarachchi, Sashiprabha M.
A1 - DeMent, Paul
A1 - Adewale, Adeleye O.
A1 - Yan, Lu
A1 - Wager-Miller, James
A1 - Ahn, Young-Hoon
A1 - Sanderson, Thomas H.
A1 - Przyklenk, Karin
A1 - Greenberg, Miriam L.
A1 - Suits, Arthur G.
A1 - Allen, Matthew J.
A1 - Narayan, Srinivas B.
A1 - Caruso, Joseph A.
A1 - Stemmer, Paul M.
A1 - Nguyen, Hien M.
A1 - Weidner, Steffen
A1 - Rackers, Kevin J.
A1 - Djuric, Ana
A1 - Shulaev, Vladimir
A1 - Hendrickson, Tamara L.
A1 - Chow, Christine S.
A1 - Pflum, Mary Kay H.
A1 - Grayson, Scott M.
A1 - Lobodin, Vladislav V.
A1 - Guo, Zhongwu
A1 - Ni, Chi-Kung
A1 - Walker, J. Michael
A1 - Mackie, Ken
A1 - Inutan, Ellen D.
A1 - McEwen, Charles N.
T1 - New Processes for Ionizing Nonvolatile Compounds in Mass Spectrometry: The Road of Discovery to Current State-of-the-Art
N2 - This Perspective covers discovery and mechanistic aspects aswell as initial applications of novel ionization processes for use in massspectrometry that guided us in a series of subsequent discoveries, instrumentdevelopments, and commercialization. Vacuum matrix-assisted ionization onan intermediate pressure matrix-assisted laser desorption/ionization sourcewithout the use of a laser, high voltages, or any other added energy wassimply unbelievable, at first. Individually and as a whole, the variousdiscoveries and inventions started to paint, inter alia, an exciting new pictureand outlook in mass spectrometry from which key developments grew thatwere at the time unimaginable, and continue to surprise us in its simplisticpreeminence. We, and others, have demonstrated exceptional analyticalutility. Our current research is focused on how best to understand, improve, and use these novel ionization processes throughdedicated platforms and source developments. These ionization processes convert volatile and nonvolatile compounds from solid orliquid matrixes into gas-phase ions for analysis by mass spectrometry using, e.g., mass-selected fragmentation and ion mobilityspectrometry to provide accurate, and sometimes improved, mass and drift time resolution. The combination of research anddiscoveries demonstrated multiple advantages of the new ionization processes and established the basis of the successes that lead tothe Biemann Medal and this Perspective. How the new ionization processes relate to traditional ionization is also presented, as wellas how these technologies can be utilized in tandem through instrument modification and implementation to increase coverage ofcomplex materials through complementary strengths.
KW - Mass spectrometry
PY - 2024
DO - https://doi.org/10.1021/jasms.3c00122
SN - 1879-1123
VL - 35
IS - 12
SP - 2753
EP - 2784
PB - American Chemical Society (ACS)
AN - OPUS4-61417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hu, W.-H
A1 - Tang, D.-H.
A1 - Wang, M.
A1 - Liu, J.-L.
A1 - Li, Z.-H.
A1 - Lu, W.
A1 - Teng, J.
A1 - Said, Samir
A1 - Rohrmann, R. G.
T1 - Resonance Monitoring of a Horizontal Wind Turbine by Strain-Based Automated Operational Modal Analysis
N2 - A strain-based automated operational modal analysis algorithm is proposed to track the long-term dynamic behavior of a horizontal wind turbine under operational conditions.
This algorithm is firstly validated by a scaled wind turbine model, and then it is applied to the dynamic strain responses recorded from a 5 MW wind turbine system. We observed variations in the fundamental frequency and 1f, 3f excitation frequencies due to the mass imbalance of the blades and aerodynamic excitation by the tower dam or tower wake. Inspection of the Campbell diagram revealed that the adverse resonance phenomenon and Sommerfeld effect causing excessive vibrations of the wind tower.
KW - Strain
KW - Automated operational modal analysis
KW - Resonance
KW - Horizontal wind turbine
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503350
DO - https://doi.org/10.3390/en13030579
VL - 13
IS - 3
SP - 579
EP - 584
PB - MDPI
CY - Schweiz, Basel
AN - OPUS4-50335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hu, W.-H.
A1 - Xu, Z.-M.
A1 - Liu, M.-Y.
A1 - Tang, D.-H.
A1 - Lu, W.
A1 - Li, Z.-H.
A1 - Teng, J.
A1 - Han, X.-H.
A1 - Said, Samir
A1 - Rohrmann, R. G.
T1 - Estimation of the Lateral Dynamic Displacement of High-Rise Buildings underWind Load Based on Fusion of a Remote Sensing Vibrometer and an Inclinometer
N2 - This paper proposes a novel method to estimate the lateral displacement of high-rise structures under wind loads. The coefficient β(x) is firstly derived, reflecting the relation between the structural lateral dynamic displacement and the inclination angle at the height x of a structure. If the angle is small, it is the ratio between the structural fundamental mode shape and its first-order derivative without influence of external loads. Several dynamic experiments of structures are performed based on a laser remote sensing vibrometer and an inclinometer, which shows that the fundamental mode is dominated in the structural displacement response under different types of excitations. Once the coefficient β(x) is curve-fitted by measuring both the structural lateral dynamic displacement and the inclination angle synchronously, the real-time structural lateral displacement under operational conditions is estimated by multiplying the coefficient β(x) with the inclination angle. The advantage of the proposed method is that the coefficient β(x) can be identified by lateral dynamic displacement measured in high resolution by the remote sensing vibrometer, which is useful to reconstruct the displacement accurately by the inclination angle under operational conditions
KW - Inclination angle
KW - High-rise building
KW - Lateral dynamic displacement
KW - Remote sensing vibrometer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506833
DO - https://doi.org/10.3390/rs12071120
VL - 12
IS - 7
SP - 1120
PB - MDPI
CY - 4052 Basel, Schweiz
AN - OPUS4-50683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Direct detection based φOTDR using the Kramers-Kronig receiver
N2 - A Kramers-Kronig (KK) receiver is applied to a phase-sensitive optical time domain reflectometry based on direct detection. An imbalanced Mach-Zehnder interferometer with a 2× 2 coupler is used in sensing system to encode the phase information into optical intensity. The directly obtained signal is treated as the in-phase component, and the KK receiver provides the quadrature component by Hilbert transform of the obtained signal, so that the optical phase can be retrieved by IQ demodulation. The working principle is well explained, and the obtained phase variance is theoretically analyzed. The experiment demonstrates the functionality of the sensor and validates the theoretical analysis.
KW - Kramers-Kronig detector
KW - Distributed fiber sensing
KW - Acoustic sensing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516803
UR - https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-28-24-37058&id=442839
DO - https://doi.org/10.1364/OE.405723
VL - 28
IS - 24
SP - 37058
EP - 37068
PB - Optical Society of America
AN - OPUS4-51680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Characterizing detection noise in phase-sensitive optical time domain reflectometry
N2 - Phase-sensitive optical time domain reflectometry (φOTDR) is an excellent distributed fiber sensing technique and has been applied in various areas. Its noise is however never been comprehensively studied to the best of our knowledge. The different detection noise sources in such a sensing system are thoroughly investigated. The impacts of thermal noise, shot noise and the beat between signal and the amplified spontaneous emission from a pre-amplifier have been theoretically and experimentally demonstrated. Due to the random nature of the φOTDR signal, the detection noise demonstrates distinct features at different fiber positions in a single measurement. The theoretical analysis and the experimental result explicitly affirm most of the fiber sections, and the difference at some positions may be explained by ambient noise.
KW - Noise analysis
KW - Acoustic sensing
KW - Distributed fiber sensing
PY - 2021
DO - https://doi.org/https://doi.org/10.1364/OE.424410
SN - 1094-4087
VL - 29
IS - 12
SP - 18791
EP - 18806
PB - Optical Society of America
CY - Washington, DC
AN - OPUS4-52757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Phase error analysis and unwrapping error suppression in phase-sensitive optical time domain reflectometry
N2 - Phase-sensitive optical time domain reflectometry becomes an effective tool to realize distributed sensing, and the optical phase of the received light is usually used to quantify the strain for both dynamic and static measurement. The analysis on the overall phase error has been improved by considering the proportionality of the detection noise to the local optical power. The estimation accuracy is greatly improved by using the proposed theory, the probability density of the estimation accuracy over 99% is > 0.6, ∼39 times larger than the previously reported method. The phase unwrapping may malfunction due to the noisy signal, causing large phase errors. Point break detection algorithms are used to locate the incorrect phase unwrapping points, so the temporal evolution of the phase retrieved at each position can be divided into several sections with different offset. The phase unwrapping error is then suppressed by removing the offset.
KW - Phase unwrapping
KW - Distributed fiber sensing
KW - Acoustic sensing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543919
DO - https://doi.org/10.1364/OE.446517
VL - 30
IS - 5
SP - 6934
EP - 6948
PB - Optica Publishing Group
AN - OPUS4-54391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Dual functionality of wavelength scanning coherent optical time domain reflectometer
N2 - Wavelength scanning coherent optical time domain reflectometer (WS-COTDR) is a good candidate to spatially resolve the environmental information at comparatively low frequency. This paper reveals it can also work as a traditional optical time domain reflectometer (OTDR) to identify Fresnel reflection by averaging the obtained signal over the wavelength scanning range. Simultaneous distributed vibration sensing and a traditional OTDR measurement are experimentally demonstrated using the WS-COTDR system.
T2 - European Workshop on Optical Fibre Sensors (EWOFS 2023)
CY - Mons, Belgium
DA - 23.05.2023
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Acoustic sensing
PY - 2023
DO - https://doi.org/10.1117/12.2678098
VL - 12643
SP - 1
EP - 4
PB - SPEI
AN - OPUS4-57590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Dual-functionality of WS-COTDR for ground movement monitoring
N2 - Wavelength scanning coherent optical time domain reflectometer (WS-COTDR) is a good candidate to spatially resolve the environmental information at comparatively low frequency. This paper reveals it can also work as a traditional optical time domain reflectometer (OTDR) to identify Fresnel reflection by averaging the obtained signal over the wavelength scanning range. Simultaneous distributed vibration sensing and a traditional OTDR measurement are experimentally demonstrated using the WS-COTDR system.
T2 - European Workshop on Optical Fibre Sensors (EWOFS 2023)
CY - Mons, Belgium
DA - 23.05.2023
KW - Distributed fiber sensing
KW - Acoustic sensing
KW - Structural health monitoring
PY - 2023
AN - OPUS4-57591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Novel fading suppression method for distributed optical fiber acoustic sensing
N2 - A universal method based on alternating pulse widths is proposed to suppress the signal fading for all distributed acoustic sensors (DASs) and experimentally demonstrated by one DAS system based on a Mach-Zehnder interferometer.
T2 - Optica Sensing Congress
CY - Munich, Germany
DA - 30.07.2023
KW - Distributed fiber sensing
KW - Acoustic sensing
KW - Fading suppression
KW - Structural health monitoring
PY - 2023
SP - 1
EP - 2
AN - OPUS4-58048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Novel fading suppression method for distributed optical fiber acoustic sensing
N2 - A universal method based on alternating pulse widths is proposed to suppress the signal fading for all distributed acoustic sensors (DASs) and experimentally demonstrated by one DAS system based on a Mach-Zehnder interferometer.
T2 - Optica Sensing Congress
CY - Munich, Germany
DA - 30.07.2023
KW - Distributed fiber sensing
KW - Acoustic sensing
KW - Structural health monitoring
KW - Fading suppression
PY - 2023
AN - OPUS4-58049
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Thomas, P.
T1 - Phase Error Evaluation via Differentiation and Cross-Multiplication Demodulation in Phase-Sensitive Optical Time-Domain Reflectometry
N2 - Phase-sensitive optical time-domain reflectometry (jOTDR) is a technology for distributed vibration sensing, where vibration amplitudes are determined by recovering the phase of the backscattered light. Measurement noise induces phase errors, which degrades sensing performance. The phase errors, using a differentiation and cross-multiplication (DCM) algorithm, are investigated theoretically and experimentally in a jOTDR system based on a phase retrieval configuration consisting of an imbalanced Mach–Zehnder interferometer (IMZI) and a 3 x 3 coupler. Analysis shows that phase error is highly dependent on the AC component of the obtained signal, essentially being inversely proportional to the product of the power of the light backscattered from two locations. An analytical expression was derived to estimate the phase error and was confirmed by experiment. When applied to the same measurement data, the error is found to be slightly smaller than that obtained using in-phase/quadrature (I/Q) demodulation. The error, however, increases for longer measurement times.
KW - Distributed fiber sensing
KW - Phase-sensitive optical time-domain reflectometry
KW - Phase error
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580501
UR - https://www.mdpi.com/2304-6732/10/5/514
DO - https://doi.org/10.3390/photonics10050514
SN - 2304-6732
VL - 10
IS - 5
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-58050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Distributed acoustic sensing to monitor ground motion/movement at multi-frequency bands
N2 - A novel distributed acoustic sensing technique is proposed that exploits both phase and amplitude of the Rayleigh backscattered light to quantify the environmental variation. The system employs a wavelength-scanning laser and an imbalanced Mach-Zehnder interferometer to acquire the reflection spectra and the phase of the detected light, respectively. Fading-free and low-frequency measurements are realized via the crosscorrelation of the reflection spectra. The discrete crosscorrelation is used to circumvent the nonlinear frequency sweeping of the laser. Based on the phase of the backscattered light, it is possible to quantify fast environmental variations. The whole system requires no hardware modification of the existing system and its functionality is experimentally validated. The proposed system has the potential to monitor ground motion/movement at very low frequency band like subsidence around mining areas and at high frequency band like earthquakes and vibrations induced by avalanches.
KW - Distributed acoustic sensing
KW - DAS
KW - Distributed fiber optic sensing
KW - Ground motion detection
KW - Subsidence monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596129
DO - https://doi.org/10.1109/JLT.2024.3358495
VL - 42
IS - 18
SP - 1
EP - 8
PB - Optical Society und IEEE Photonics Society
AN - OPUS4-59612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Approaching distributed ground motion sensing at high and low frequency ranges
N2 - The phase and reflection spectrum of a standard distributed acoustic sensor based on an interferometer are used for fast and slow dynamic measurements, respectively, enabling the system to simultaneously measure various types of ground movement.
T2 - 28th International Conference on Optical Fiber Sensors (OFS-28)
CY - Hamamatsu, Japan
DA - 20.11.2023
KW - Distributed acoustic sensing
KW - Ground movement monitoring
KW - Geomonitoring
KW - Interferometer-based
KW - DAS
PY - 2023
SP - 1
EP - 4
PB - Optica
CY - Washington D.C., USA
AN - OPUS4-59098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
T1 - Introduction to group 8.6
N2 - A brief introduction of group 8.6 and the research work on the application of fiber sensing.
T2 - DIU Besuch
CY - Berlin, Germany
DA - 05.05.2023
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Distributed acoustic sensing
KW - Practical application
PY - 2023
AN - OPUS4-57430
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Davison, Nathan
A1 - Hemingway, Jack M.
A1 - Wills, Corinne
A1 - Stolar, Tomislav
A1 - Waddell, Paul G.
A1 - Dixon, Casey M.
A1 - Barron, Luke
A1 - Dawson, James A.
A1 - Lu, Erli
T1 - Mechanochemical Synthesis of a Sodium Anion Complex [Na+(2,2,2-cryptand)Na–] and Studies of Its Reactivity: Two-Electron and One-Electron Reductions
N2 - Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is −1, i.e., alkalide. Reported as early as the 1970s, the alkalides appear in every modern inorganic chemistry textbook as an iconic chemical curiosity, yet their reactivity remains unexplored. This is due to their synthetic hurdles. In this work, we report the first facile synthesis of the archetypical alkalide complex, [Na+(2,2,2-cryptand)Na–], which allows us to unveil a versatile reactivity profile of this once exotic species.
KW - Mechanochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608632
DO - https://doi.org/10.1021/acs.inorgchem.4c02914
VL - 63
IS - 32
SP - 15247
EP - 15258
PB - American Chemical Society (ACS)
AN - OPUS4-60863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hellemans, S.
A1 - Rocha, M. M.
A1 - Wang, M.
A1 - Romero Arias, J.
A1 - Aanen, D. K.
A1 - Bagnères, A.-G.
A1 - Buček, A.
A1 - Carrijo, T. F.
A1 - Chouvenc, T.
A1 - Cuezzo, C.
A1 - Constantini, J. P.
A1 - Constantino, R.
A1 - Dedeine, F.
A1 - Deligne, J.
A1 - Eggleton, P.
A1 - Evans, T. A.
A1 - Hanus, R.
A1 - Harrison, Mark C.
A1 - Harry, M.
A1 - Josens, G.
A1 - Jouault, C.
A1 - Kalleshwaraswamy, C. M.
A1 - Kaymak, E.
A1 - Korb, J.
A1 - Lee, C.-Y.
A1 - Legendre, F.
A1 - Li, H.-F.
A1 - Lo, N.
A1 - Lu, T.
A1 - Matsuura, K.
A1 - Maekawa, K.
A1 - McMahon, Dino Peter
A1 - Mizumoto, N.
A1 - Oliveira, D. E.
A1 - Poulsen, M.
A1 - Sillam-Dussès, D.
A1 - Su, N.-Y.
A1 - Tokuda, G.
A1 - Vargo, E. L.
A1 - Ware, J. L.
A1 - Šobotník, J.
A1 - Scheffrahn, R. H.
A1 - Cancello, E.
A1 - Roisin, Y.
A1 - Engel, M. S.
A1 - Bourguignon, T.
T1 - Genomic data provide insights into the classification of extant termites
N2 - The higher classification of termites requires substantial revision as the Neoisoptera, the most diverse termite lineage, comprise many paraphyletic and polyphyletic higher taxa. Here, we produce an updated termite classification using genomic-scale analyses. We reconstruct phylogenies under diverse substitution models with ultraconserved elements analyzed as concatenated matrices or within the multi-species coalescence framework. Our classification is further supported by analyses controlling for rogue loci and taxa, and topological tests. We show that the Neoisoptera are composed of seven family-level monophyletic lineages, including the Heterotermitidae Froggatt, Psammotermitidae Holmgren, and Termitogetonidae Holmgren, raised from subfamilial rank. The species-rich Termitidae are composed of 18 subfamily-level monophyletic lineages, including the new subfamilies Crepititermitinae, Cylindrotermitinae, Forficulitermitinae, Neocapritermitinae, Protohamitermitinae, and Promirotermitinae; and the revived Amitermitinae Kemner, Microcerotermitinae Holmgren, and Mirocapritermitinae Kemner. Building an updated taxonomic classification on the foundation of unambiguously supported monophyletic lineages makes it highly resilient to potential destabilization caused by the future availability of novel phylogenetic markers and methods. The taxonomic stability is further guaranteed by the modularity of the new termite classification, designed to accommodate as-yet undescribed species with uncertain affinities to the herein delimited monophyletic lineages in the form of new families or subfamilies.
KW - Termite
KW - Taxonomy
KW - Evolution
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608276
DO - https://doi.org/10.1038/s41467-024-51028-y
VL - 15
IS - 1
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-60827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Configuration simplification and data reduction in a DAS system for monitoring large infrastructures
N2 - The distributed acoustic sensor based on an imbalanced Mach-Zehnder interferometer with a 3×3 coupler is simplified by using a balanced detector instead of three identical photodetectors. The obtained data is reduced by two third accordingly.
T2 - Optica Sensing Congress 2024
CY - Toulouse, France
DA - 15.07.2024
KW - Data reduction
KW - Distributed fiber optic sensing
KW - System simplification
PY - 2024
SP - 1
EP - 2
PB - Optica
CY - Washington D.C., USA
AN - OPUS4-60840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
T1 - Configuration simplification and data reduction in a DAS system for monitoring large infrastructures
N2 - The distributed acoustic sensor based on an imbalanced Mach-Zehnder interferometer with a 3×3 coupler is simplified by using a balanced detector instead of three identical photodetectors. The obtained data is reduced by two third accordingly.
T2 - Optica Sensing Congress 2024
CY - Toulouse, France
DA - 15.07.2024
KW - Distributed fiber sensing
KW - System simplification
KW - Data reduction
PY - 2024
AN - OPUS4-60841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hicke, Konstantin
A1 - Lu, Xin
A1 - Chruscicki, Sebastian
A1 - Krebber, Katerina
T1 - Measurement of Slowly Changing and Quasi-Static Strain Signals for Ground Motion Monitoring Applications using Distributed Acoustic Sensing
N2 - The suitability of wavelength-scanning COTDR for distributed dynamic strain sensing (DAS) along buried fiber cables for long-term geotechnical monitoring applications is demonstrated by experiments showing the method’s capability to demodulate slowly varying and quasi-static signals.
T2 - Optica Sensing Congress 2024
CY - Toulouse, France
DA - 15.07.2024
KW - Ground motion
KW - Ground movement monitoring
KW - Distributed fiber optic sensing
KW - Quasi-static signals
KW - Geomonitoring
PY - 2024
SP - 1
EP - 2
PB - Optica
CY - Washington D.C., USA
AN - OPUS4-60816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Suppression of Rayleigh fading induced errors in φOTDR by different pulse widths for improving the reliability of civil infrastructure monitoring
N2 - Rayleigh fading is a widely observed phenomenon in the many fields, such as wireless communication and optical imaging. It is also the main factor limiting the performance of the phase-sensitive optical time domain reflectometry (φOTDR). The low SNR at the fading points results in a large measurement error, severely affecting the reliability of civil infrastructure monitoring. The proposed method involves changing the pulse width during measurements to suppress the impact of fading. Experimental result shows that the number of fading points is greatly reduced by ∼ 96 % and the measurement error is reduced by more than 5 times. Unlike existing methods, this approach requires no hardware modifications, making it applicable to almost all current phase-based φOTDR systems. The versatility and effectiveness of this method make it an excellent candidate for infrastructure monitoring and related fields.
KW - Distributed fiber sensing
KW - Optical fiber sensing
KW - Phase-sensitive optical time domain reflectometry
KW - Infrastructure monitoring
KW - Rayleigh fading
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614208
DO - https://doi.org/10.1016/j.optlastec.2024.111927
SN - 1879-2545
VL - 181
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-61420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Distributed fiber optic sensing for monitoring of underground facilities
N2 - Distributed fiber optic sensing (DFOS) technique is a promising and robust non-destructive testing tool that can seamlessly acquire environmental conditions over large scales. Therefore, it has found extensive applications in structural health monitoring. Its appeal for monitoring underground facilities lies in the intrinsic properties of the optical fiber, such as immunity to magnetic interference, small size, chemical inertia, etc. This paper provides a concise overview of DFOS applications in underground facility monitoring. Following a brief introduction to the working principle of the DFOS technique, various examples are provided to demonstrate how distributed fiber sensors contribute to monitoring underground facilities. The paper presents unpublished field test results with an emphasis in the energy sector, including monitoring gas storage facilities, geothermal reservoir exploration, and ground movement detection. Furthermore, the paper identifies several directions for enhancing the DFOS system.
T2 - SPIE Photonics Europe
CY - Strasbourg, France
DA - 07.04.2024
KW - Underground gas storage
KW - Distributed fiber sensing
KW - Geothermal borehole
KW - Ground movement
KW - Leakage detection
KW - Structure health monitoring
PY - 2024
AN - OPUS4-60146
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Distributed fiber optic sensing for monitoring of underground facilities
N2 - Distributed fiber optic sensing (DFOS) technique is a promising and robust non-destructive testing tool that can seamlessly acquire environmental conditions over large scales. Therefore, it has found extensive applications in structural health monitoring. Its appeal for monitoring underground facilities lies in the intrinsic properties of the optical fiber, such as immunity to magnetic interference, small size, chemical inertia, etc. This paper provides a concise overview of DFOS applications in underground facility monitoring. Following a brief introduction to the workingbnprinciple of the DFOS technique, various examples are provided to demonstrate how distributed fiber sensors contribute to monitoring underground facilities. The paper presents unpublished field test results with an emphasis in the energy sector, including monitoring gas storage facilities, geothermal reservoir exploration, and ground movement detection. Furthermore, the paper identifies several directions for enhancing the DFOS system.
T2 - SPIE Photonics Europe
CY - Strasbourg, France
DA - 07.04.2024
KW - Structure health monitoring
KW - Geothermal borehole
KW - Distributed fiber optic sensing
KW - Ground movement
KW - Leakage detection
PY - 2024
DO - https://doi.org/10.1117/12.3023571
SN - 0277-786X
VL - 13001
SP - 1
EP - 10
PB - SPIE
AN - OPUS4-60384
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang,
A1 - Zheng,
A1 - Zhang,
A1 - Lu,
A1 - Wang,
A1 - Kunte, Hans-Jörg
A1 - Sand, W.
T1 - Long Term Temperature and Humidity Evolution Forecast in Near Field of Nuclear Waste Container
N2 - The paper aims to simulate the corrosion environment of nuclear waste containers at different geological disposal periods to obtain temperature and humidity information at the interface between the container and the surrounding environment. The simulated data and calculation results of long term temperature evolution at the surface of nuclear waste (HLW) containers from some typical nuclear countries about the safety disposition were reviewed. Combining different burial patterns, this paper speculated the long term temperature evolution rule for China. According to the study about saturation variation of buffer/backfill material at home and abroad, the humidity evolution of bentonite at the surface of HLW containers was specu- lated. The study showed that the temperature of the container surface increased rapidly at the beginning, and gradually decreased after the climax. For safety reasons, the maximum temperature was designed below 100°C. The saturation of bentonite was af- fected by the mutual influences of the heat released by nuclear waste decay and the infiltration of groundwater. It was dominated by the released heat in the early stage, and later was influenced greatly by the infiltration of groundwater. It is generally believed that the water content at the surface of the container will increase obviously in about 3 years, and will be saturated in about 10 years. The prediction of long-term temperature and humidity evolution will lay a foundation for study of corrosion evolution of nuclear waste containers in China.
KW - Corrosion evolution
KW - Nuclear waste
KW - Disposal repository
KW - Temperature and humidity
PY - 2018
SN - 1672-9242
VL - 15
IS - 10
SP - 109
EP - 113
PB - Zhongguo Bingqi Gongye di-wujiu Yanjiusuo
CY - Chongqing
AN - OPUS4-46953
LA - zho
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang, Y.-L.
A1 - Zheng,
A1 - Zhang,
A1 - Lu,
A1 - Wang,
A1 - Kunte, Hans-Jörg
A1 - Sand, W.
T1 - Forecast on Long Term Chemical Environment Evolution on Surface of Nuclear Waste Container
N2 - Surface environment changes of nuclear waste container, mainly including oxygen contents, buffer pore water components and pH under the conditions of “borehole” type and “In-floor” type with bentonite buffer/backfill and concrete buffer were summarized. This summarization provides a basic corrosion environment reference for the corrosion evolution re- search of high-level radioactive waste disposal repository in our country.
KW - Corrosion evolution
KW - Nuclear waste
KW - Disposal repository
KW - Corrosion environment
PY - 2018
DO - https://doi.org/10.7643/ issn.1672-9242.2018.10.017
SN - 1672-9242
VL - 15
IS - 10
SP - 103
EP - 108
PB - Zhongguo Bingqi Gongye di-wujiu Yanjiusuo
CY - Chongqing
AN - OPUS4-46952
LA - zho
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Christensen, J. B.
A1 - Jørgensen, A. A.
A1 - Vandborg, M. H.
A1 - Thomas, P. J.
A1 - Lu, Xin
A1 - Failleau, G.
A1 - Eisermann, R.
A1 - Grüner-Nielsen, L.
A1 - Balslev-Harder, D.
A1 - Lassen, M.
A1 - Krenek, S.
T1 - Fiber-artefact methodology and calibration framework for Brillouin-based fiber sensing
N2 - We propose, and demonstrate, the use of a fiber-optical measurement artefact as a metrological tool for traceable distance calibration of distributed optical fiber sensors. The constructed fiber artefact consists of a lead-in fiber coupled to a fiber loop using a 3-dB coupler and is used to calibrate both a home-build Brillouin-OTDR setup and a custom version of a commercial Brillouin-OTDR interrogator build for distributed temperature sensing. For both interrogators, we demonstrate distance calibrations with 1-meter uncertainty (k=1) in the offset length and 0.1 % (1 m/km) uncertainty (k = 1) in the distance scale factor. In addition, it is shown that the fiber artefact can be used to assess undesired distance-dependent measurement biases.
KW - Distributed temperature sensing
KW - Metrology
KW - Distributed optical fiber sensing
KW - Brillouin optical time-domain reflectrometry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618853
DO - https://doi.org/10.1364/OE.544659
SN - 1094-4087
VL - 32
IS - 26
SP - 45483
EP - 45493
PB - Optica Publishing Group
AN - OPUS4-61885
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
T1 - Progress review
N2 - We report on the progress on calibration and characterization of distributed temperature sensing systems as a part of the European INFOTherm project. The most research results were achieved in the framework of the Work Package 2.
T2 - Midterm meeting of INFOTherm project
CY - Copenhagen, Denmark
DA - 25.03.2025
KW - Humidity sensor
KW - Optical fibre sensors
KW - Distributed temperature sensing
PY - 2025
AN - OPUS4-63007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Breithaupt, Mathias
A1 - Strangfeld, Christoph
T1 - Distributed Humidity Sensing in Concrete Based on Polymer Optical Fiber
N2 - We present a preliminary investigation on distributed humidity monitoring during the drying process of concrete based on an embedded polymer optical fiber (POF). The water dissipated into the POF changes several properties of the fiber such as refractive index, scattering coefficient and attenuation factor, which eventually alters the Rayleigh backscattered light. The optical time Domain reflectometer (OTDR) technique is performed to acquire the backscattered signal at the wavelengths 650 nm and 500 nm, respectively. Experimental results show that the received signal increases at 650 nm while the fiber attenuation factor clearly increases at 500 nm, as the concrete dries out. In the hygroscopic range, the information retrieved from the signal change at 650 nm agrees well with the measurement result of the electrical humidity sensors also embedded in the concrete sample.
KW - Distributed fiber optic sensing
KW - Distributed humidity sensing
KW - Polymer optical fibers
KW - Concrete drying
KW - Material moisture
KW - Embedded humidity sensors
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537644
DO - https://doi.org/10.3390/polym13213755
SN - 2073-4360
VL - 13
IS - 21
SP - 3755
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-53764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hu, W.
A1 - Said, Samir
A1 - Rohrmann, R.
A1 - Teng, J.
A1 - Li, Z.
A1 - Lu, W.
A1 - Cunha, A.
T1 - Operational modal analysis and continuous dynamic monitoring of structures
N2 - This paper addresses operational modal analysis (OMA) and continuous dynamic monitoring (CDM) of two bridges. One of them is installed with Tuned Mass Dampers (TMDs) while another one is a normal bridge. Two ambient vibration tests were performed on these two bridges respectively. It is observed that not only installation of TMDs but also environmental factors influence the variations of structural frequencies, which may mask the subtle change induced by small structural changes. As a result, continuous dynamic monitoring systems were implemented on these two bridges, in order to evaluate efficiency of the TMD system, remove the environmental effects and build reliable damage indices that are only sensitive to structural changes. The results of CDM of these two bridges during several years are presented. Software systems developed for OMA and CDM are also introduced.
T2 - 14th International Symposium on Structural Engineering (ISSE-14)
CY - Beijing, Peoples Republic of China
DA - 12.10.2016
KW - Structure
KW - Operational modal analysis
KW - Continuous dynamic monitoring
PY - 2016
SN - 978-7-03-050125-7
VL - 2016
SP - 366
EP - 372
PB - Science Press Beijing
AN - OPUS4-38876
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Qiu, Q.
A1 - Noll, Matthias
A1 - Abraham, W.-R.
A1 - Lu, Y.
A1 - Conrad, R.
T1 - Applying stable isotope probing of phospholipid fatty acids and rRNA in a Chinese rice field to study activity and composition of the methanotrophic bacterial communities in situ
N2 - Methanotrophs in the rhizosphere play an important role in global climate change since they attenuate methane emission from rice field ecosystems into the atmosphere. Most of the CH4 is emitted via transport through the plant gas vascular system. We used this transport for stable isotope probing (SIP) of the methanotrophs in the rhizosphere under field conditions and pulse-labelled rice plants in a Chinese rice field with CH4 (99% 13C) for 7 days. The rate of 13CH4 loss rate during 13C application was comparable to the CH4 oxidation rate measured by the difluoromethane inhibition technique. The methanotrophic communities on the roots and in the rhizospheric soil were analyzed by terminal-restriction fragment length polymorphism (T-RFLP), cloning and sequencing of the particulate methane monooxygenase (pmoA) gene. Populations of type I methanotrophs were larger than those of type II. Both methane oxidation rates and composition of methanotrophic communities suggested that there was little difference between urea-fertilized and unfertilized fields. SIP of phospholipid fatty acids (PLFA-SIP) and rRNA (RNA-SIP) were used to analyze the metabolically active methanotrophic community in rhizospheric soil. PLFA of type I compared with type II methanotrophs was labelled more strongly with 13C, reaching a maximum of 6.8 atom-% . T-RFLP analysis and cloning/sequencing of 16S rRNA genes showed that methanotrophs, especially of type I, were slightly enriched in the 'heavy' fractions. Our results indicate that CH4 oxidation in the rice rhizosphere under in situ conditions is mainly due to type I methanotrophs.
KW - Methane-oxidizing bacteria
KW - Rice field
KW - Rhizosphere
KW - Stable isotope probing
KW - Phospholipid fatty acid
KW - Particulate methane monooxygenase
PY - 2008
DO - https://doi.org/10.1038/ismej.2008.34
SN - 1751-7362
SN - 1751-7370
IS - 2
SP - 602
EP - 614
PB - Nature Publishing Group
CY - Basingstoke
AN - OPUS4-17660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, P.
A1 - Lannutti, J.J.
A1 - Klobes, Peter
A1 - Meyer, Klaus
T1 - X-ray Computed Tomography and Mercury Porosimetry for Evaluation of Density Evolution and Porosity Distribution
N2 - X-ray computed tomography (CT) and mercury porosimetry were combined to connect density gradients and the distribution of open porosity in a sintered compact. CT clearly showed that open porosity follows the initial distribution of low-density zones. Mercury porosimetry detected three distinct levels of porosity. Microstructural examination correlated the porosity level with the coordination of (i) two to three or (ii) multiple grains around pores. This combination of techniques provides a novel tool for the study of pore and density-gradient evolution during sintering.
PY - 2000
DO - https://doi.org/10.1111/j.1151-2916.2000.tb01227.x
SN - 0002-7820
SN - 1551-2916
VL - 83
IS - 3
SP - 518
EP - 522
PB - Blackwell Publishing
CY - Malden
AN - OPUS4-11955
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bothe, Martin
A1 - Mya, K.Y.
A1 - Lin, E.M.J.
A1 - Yeo, C. C.
A1 - Lu, X.
A1 - He, C.
A1 - Pretsch, Thorsten
T1 - Triple-shape properties of star-shaped POSS-polycaprolactone polyurethane networks
N2 - Here, we present an investigation of the triple-shape properties of star-shaped polyhedral oligomeric silsesquioxane-poly(ε-caprolactone) polyurethanes (SPOSS-PUs), which have three-dimensional network structures. In a typical 'triple-shape functionalization process', mostly consisting of two tensile deformations at different temperatures, chain immobilization of the polymer network component poly(ε-caprolactone) (PCL) was successfully realized first through crystallization and then through vitrification. Subsequently, large parts of the respective strains were released under stress-free recovery conditions. The two-fold fixed ('programmed') specimens responded to heating with two independent length contractions (switching steps); the first shape change was associated with PCL devitrification and the second one with the melting of hitherto crystalline PCL. It was revealed that the triple-shape properties of SPOSS-PU networks considerably depend on PCL network chain length. When applying exactly the same 'triple-shape creation procedure', larger strain releases were detected in the first transition for polymers with a higher PCL network chain length, whereas the second transition was more accentuated for SPOSS-PU networks with a shorter PCL chain length. In the course of thermo-mechanical cycling, the formation of a neck during the second tensile deformation was repeatedly detected for SPOSS-PUs with higher PCL network chain length; in the subsequent recovery process the specimens even exhibited the highest total strain recoverability. Finally, gradual strain release could be achieved at temperatures below the PCL melting transition through the selection of up to four temperature holding steps, at which every time stable shapes were formed.
KW - Shape memory polymer
KW - Active polymer
KW - Triple-shape polymer
KW - Hybrid star-shaped polymer
KW - POSS-polycaprolactone polyurethanes
KW - Thermo-mechanical properties
PY - 2012
DO - https://doi.org/10.1039/c1sm06474f
SN - 1744-683X
VL - 8
IS - 4
SP - 965
EP - 972
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-25260
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
T1 - Humidity response analysis of optical fibers with hygroscopic coatings based on Lamé’s equations
N2 - Optical fibers with hygroscopic coatings are widely used for humidity sensing, where the coating expands upon absorbing water, inducing strain in the fiber. This strain is then used to determine humidity. However, previous studies have oversimplified the strain generation process. A comprehensive three-dimensional model of the mechanical interaction between the coating and the fiber is built based on Lamé’s equations. An analytical expression for the induced strain is derived. The proposed model predicts larger humidity-induced strain compared to the reported ones, given the same Young’s modulus or coefficient of humidity expansion for the coating. Interestingly, the effect of coating thickness on strain response are quite similar for both methods. Experimental validation using fibers with a polyimide coating shows strong agreement with the theoretical predictions.
T2 - 29th International Conference on Optical Fiber Sensors
CY - Porto, Portugal
DA - 26.05.2025
KW - Distributed fiber sensing
KW - Humidity sensors
KW - Lamé’s equations
KW - Reflectometry
KW - Optical fiber sensors
KW - Rayleigh scattering
KW - Structural health monitoring
PY - 2025
AN - OPUS4-63261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
T1 - Polarization diversity detection based wavelength scanning coherent optical time domain reflectometry
N2 - Although wavelength scanning coherent optical time-domain reflectometry (WS-COTDR) system is immune to fading effect, it suffers from occasional and localized large errors caused by the false peak in the correlation spectrum due to the large signal generated in the random interference of the backscattered light. Polarization diversity detection is applied to a standard WS-COTDR system to suppress large measurement errors. In this way, the orthogonally polarized components of backscattered light can be obtained and processed separately. Due to the birefringence of the sensing fiber, the components experience different interference processes, so the average of their correlation spectrum can suppress the false peaks and finally reduce the occurrence of larger errors. The effectiveness of the proposed method is validated in laboratory for monitoring of sinusoidal vibrations and in field for tracking the bus movement via a dark fiber.
T2 - 29th International Conference on Optical Fiber Sensors
CY - Porto, Portugal
DA - 26.05.2025
KW - Coherent optical time domain reflectometry
KW - Traffic monitoring
KW - Polarization diversity detection
KW - Distributed fiber sensing
PY - 2025
AN - OPUS4-63260
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Großwig, S.
A1 - Weber, U.
A1 - Krebber, Katerina
T1 - Monitoring acoustic events in boreholes using wavelengthscanning coherent optical time domain reflectometry in multimode fiber
N2 - A distributed acoustic sensor (DAS) based on wavelength-scanning coherent optical time domain reflectometer (WS-COTDR) is tested in an underground gas storage based on a multimode fiber for the first time to the best of our knowledge. The WS-COTDR acquires the reflection spectrum by scanning the wavelength of the laser and uses the spectra to calibrate strain. It overcomes the fading problem which is common for all DAS systems, and possesses the advantage of simple configuration and low-cost. The working principle of the system is well explained and the measurement results are presented. Various artificial and natural acoustic events have been successfully detected by the WS-COTDR. Such a sensor demonstrates several advantages over the traditional DAS systems, so it is supposed to be widely used in the oil and gas industry.
T2 - EAGE GeoTech 2021 Second EAGE Workshop on Distributed Fibre Optic Sensing
CY - Online meeting
DA - 01.03.2021
KW - Leakage detection
KW - Distributed acoustic sensing
KW - Distributed fiber optic sensing
PY - 2021
DO - https://doi.org/10.3997/2214-4609.202131010
SP - Paper 10, 1
PB - European Association of Geoscientists & Engineers
CY - Houten, Niederlande
AN - OPUS4-52248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Großwig, S.
A1 - Weber, U.
A1 - Krebber, Katerina
T1 - Monitoring acoustic events in boreholes using wavelengthscanning coherent optical time domain reflectometry in multimode fiber
N2 - A distributed acoustic sensor (DAS) based on wavelength-scanning coherent optical time domain reflectometer (WS-COTDR) is tested in an underground gas storage based on a multimode fiber for the first time to the best of our knowledge. The WS-COTDR acquires the reflection spectrum by scanning the wavelength of the laser and uses the spectra to calibrate strain. It overcomes the fading problem which is common for all DAS systems, and possesses the advantage of simple configuration and low-cost. The working principle of the system is well explained and the measurement results are presented. Various artificial and natural acoustic events have been successfully detected by the WS-COTDR. Such a sensor demonstrates several advantages over the traditional DAS systems, so it is supposed to be widely used in the oil and gas industry.
T2 - EAGE GeoTech 2021
CY - Online meeting
DA - 01.03.2021
KW - Borehole monitoring
KW - Distributed fiber sensing
KW - Acoustic sensing
PY - 2021
DO - https://doi.org/10.3997/2214-4609.202131010
SP - 1
EP - 5
AN - OPUS4-52152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krebber, Katerina
A1 - Weege, S.
A1 - Großwig, S.
A1 - Obermöller, M.
A1 - Perk, M.
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Weber, U.
A1 - Pfeiffer, T.
A1 - Rembe, M.
T1 - Kombinierte faseroptische Messungen in Bohrlöchern helfen bei der Detektion von Kleinstleckagen
N2 - Seit November 2019 läuft ein breit angelegtes und vom BMWi gefördertes ZIM-Kooperationsprojekt zwischen der Bundesanstalt für Materialforschung und -prüfung (BAM), der IAB'Weimar gGmbH, der GKSO GmbH & Co. Projekt KG, der DEEP.KBB GmbH sowie der Rembe Consulting PartG mbB. Ziel des Forschungsvorhabens sind sowohl die Lokalisierung als auch die Quantifizierung insbesondere sehr kleiner Leckagen in einer Bohrlochverrohrung durch die Nutzung faseroptischer Messtechnik. Durch Messdatenkopplung und den Wegfall bewegungsbedingter Nachteile einer Messsonde werden wesentlich präzisere Ergebnisse zur Bewertung der Bohrlochintegrität als üblich
erwartet.
T2 - DGMK/ÖGEW-Frühjahrstagung 2020
CY - Meeting was canceled
DA - 15.04.2020
KW - Wasserstoffspeicher
KW - Kavernenspeicher
KW - Verteilte faseroptische akustische Sensorik
PY - 2020
VL - 6
SP - 43
EP - 43
PB - DVV Media Group
CY - Hamburg
AN - OPUS4-52233
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Krebber, Katerina
T1 - Characterizing vibration response of fiber cables for distributed acoustic sensing
N2 - The vibration responses of two fiber cables are characterized up to 16 kHz and compared with a standard tight-buffered 900 um fiber. The response of the cables is suppressed due to the cable protection.
T2 - 27th International Conference on Optical Fiber Sensors (OFS-27)
CY - Alexandria, VA, USA
DA - 29.08.2022
KW - Distributed fiber sensing
KW - Acoustic sensing
KW - Response characterization
PY - 2022
AN - OPUS4-56099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Weege, S.
A1 - Roske, T.
A1 - Krebber, Katerina
T1 - Leakage detection at a borehole simulator using distributed acoustic sensing
N2 - A distributed acoustic sensing system is used to detect the leakage in a borehole simulator by measuring the leakage induced vibration. The leakage location can be clearly determined by frequency spectrum analysis.
T2 - 27th International Conference on Optical Fiber Sensors (OFS-27)
CY - Alexandria, VA, USA
DA - 29.08.2022
KW - Leakage detection
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Distributed acoustic sensing
PY - 2022
SP - 1
EP - 4
PB - Optica
CY - Washington D.C., USA
AN - OPUS4-56097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Krebber, Katerina
T1 - Characterizing vibration response of fiber cables for distributed acoustic sensing
N2 - The vibration responses of two fiber cables are characterized up to 16 kHz and compared with a standard tight-buffered 900 um fiber. The response of the cables is suppressed due to the cable protection
T2 - 27th International Conference on Optical Fiber Sensors (OFS-27)
CY - Alexandria, VA, USA
DA - 29.08.2022
KW - Response characterization
KW - Distributed fiber sensing
KW - Acoustic sensing
PY - 2022
SP - 1
EP - 4
PB - Optica
CY - Washington D.C., USA
AN - OPUS4-56096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Weege, S.
A1 - Roske, T.
A1 - Krebber, Katerina
T1 - Leakage detection at a borehole simulator using distributed acoustic sensing
N2 - A distributed acoustic sensing system is used to detect the leakage in a borehole simulator by measuring the leakage induced vibration. The leakage location can be clearly determined by frequency spectrum analysis.
T2 - 27th International Conference on Optical Fiber Sensors (OFS-27)
CY - Alexandria, VA, USA
DA - 29.08.2022
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Distributed acoustic sensing
KW - Leakage detection
PY - 2022
AN - OPUS4-56098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wang, Kun
A1 - Lu, Xin
A1 - Schukar, Marcus
A1 - Hicke, Konstantin
T1 - Water absorption effects on distributed temperature sensing using polyimide-coated optical fiber
N2 - Polyimide-coated fibers are becoming more popular for distributed temperature sensing (DTS) because this coating can withstand much higher temperatures than the standard acrylate coating. As a hygroscopic material, polyimide can absorb water from the air, changing its properties, which may result in a modified temperature response of the sensing fiber. This study investigates the effect of water absorption on the performance of polyimide-coated optical fibers with different sizes and properties. The thermal response of these fibers was determined experimentally from 20°C to 90°C at a broad relative humidity level ranging from 10% to 90%. The results show that all the fibers experienced a decrease in temperature sensitivity as humidity increased, with the most noticeable non-linear spectral shift observed at higher humidity levels. These findings highlight the importance of optimizing fiber design and coating properties to balance stability and sensitivity, ensuring the reliable performance of DTS systems under extreme environmental conditions.
T2 - 29th International Conference on Optical Fiber Sensors
CY - Porto, Portugal
DA - 26.05.2025
KW - Humidity sensing
KW - Distributed temperature sensing
KW - Optical fiber sensors
KW - Temperature sensing
KW - Water absorption
KW - Polyimide-coated fiber
PY - 2025
SN - 978-1-5106-9187-2
DO - https://doi.org/10.1117/12.3062748
VL - 13639
SP - 136393W-1
EP - 136393W-4
PB - SPIE
AN - OPUS4-63642
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Schukar, Marcus
T1 - Humidity response analysis of optical fibers with hygroscopic coatings based on Lamé’s equations
N2 - Optical fibers with hygroscopic coatings are widely used for humidity sensing, where the coating expands upon absorbing water, inducing strain in the fiber. This strain is then used to determine humidity. However, previous studies have oversimplified the strain generation process. A comprehensive three-dimensional model of the mechanical interaction between the coating and the fiber is built based on Lamé’s equations. An analytical expression for the induced strain is derived. The proposed model predicts larger humidity-induced strain compared to the reported ones, given the same Young’s modulus or coefficient of humidity expansion for the coating. Interestingly, the effect of coating thickness on strain response are quite similar for both methods. Experimental validation using fibers with a polyimide coating shows strong agreement with the theoretical predictions.
T2 - 29th International Conference on Optical Fiber Sensors
CY - Porto, Portugal
DA - 26.05.2025
KW - Reflectometry
KW - Distributed fiber sensing
KW - Humidity sensors
KW - Lamé’s equations
KW - Optical fiber sensors
KW - Structural health monitoring
KW - Rayleigh scattering
PY - 2025
SN - 978-1-5106-9188-9
DO - https://doi.org/10.1117/12.3060891
VL - 13639
SP - 1
EP - 4
PB - SPIE
AN - OPUS4-63257
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lu, Xin
A1 - Hicke, Konstantin
T1 - Polarization-diversity-detection-based wavelength-scanning coherent-optical-time-domain reflectometer and its application for bus monitoring
N2 - Although wavelength scanning coherent optical time-domain reflectometry (WS-COTDR) system is immune to fading effect, it suffers from occasional and localized large errors caused by the false peak in the correlation spectrum due to the large signal generated in the random interference of the backscattered light. Polarization diversity detection is applied to a standard WS-COTDR system to suppress large measurement errors. In this way, the orthogonally polarized components of backscattered light can be obtained and processed separately. Due to the birefringence of the sensing fiber, the components experience different interference processes, so the average of their correlation spectrum can suppress the false peaks and finally reduce the occurrence of larger errors. The effectiveness of the proposed method is validated in laboratory for monitoring of sinusoidal vibrations and in field for tracking the bus movement via a dark fiber.
T2 - 29th International Conference on Optical Fiber Sensors
CY - Porto, Portugal
DA - 26.05.2025
KW - Traffic monitoring
KW - Coherent optical time domain reflectometry
KW - Distributed fiber sensing
KW - Polarization diversity detection
PY - 2025
SN - 978-1-5106-9187-2
DO - https://doi.org/10.1117/12.3060889
VL - 13639
SP - 1
EP - 4
PB - SPIE
AN - OPUS4-63258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chan, George C.-Y.
A1 - Hieftje, Gary M.
A1 - Omenetto, Nicoló
A1 - Axner, Ove
A1 - Bengtson, Arne
A1 - Bings, Nicolas H.
A1 - Blades, Michael W.
A1 - Bogaerts, Annemie
A1 - Bolshov, Mikhail A.
A1 - Broekaert, José A.C.
A1 - Chan, WingTat
A1 - Costa-Fernández, José M.
A1 - Crouch, Stanley R.
A1 - De Giacomo, Alessandro
A1 - D’Ulivo, Alessandro
A1 - Engelhard, Carsten
A1 - Falk, Heinz
A1 - Farnsworth, Paul B.
A1 - Florek, Stefan
A1 - Gamez, Gerardo
A1 - Gornushkin, Igor B.
A1 - Günther, Detlef
A1 - Hahn, David W.
A1 - Hang, Wei
A1 - Hoffmann, Volker
A1 - Jakubowski, Norbert
A1 - Karanassios, Vassili
A1 - Koppenaal, David W.
A1 - Kenneth Marcus, R.
A1 - Noll, Reinhard
A1 - Olesik, John W.
A1 - Palleschi, Vincenzo
A1 - Panne, Ulrich
A1 - Pisonero, Jorge
A1 - Ray, Steven J.
A1 - Resano, Martín
A1 - Russo, Richard E.
A1 - Scheeline, Alexander
A1 - Smith, Benjamin W.
A1 - Sturgeon, Ralph E.
A1 - Todolí, José-Luis
A1 - Tognoni, Elisabetta
A1 - Vanhaecke, Frank
A1 - Webb, Michael R.
A1 - Winefordner, James D.
A1 - Yang, Lu
A1 - Yu, Jin
A1 - Zhang, Zhanxia
T1 - Landmark Publications in Analytical Atomic Spectrometry: Fundamentals and
Instrumentation Development
N2 - The almost-two-centuries history of spectrochemical analysis has generated a body of literature so vast that it has become nearly intractable for experts, much less for those wishing to enter the field. Authoritative, focused reviews help to address this problem but become so granular that the overall directions of the field are lost. This broader perspective can be provided partially by general overviews but then the thinking, experimental details, theoretical underpinnings and instrumental innovations of the original work must be sacrificed. In the present compilation, this dilemma is overcome by assembling the most impactful publications in the area of analytical atomic spectrometry. Each entry was proposed by at least one current expert in the field and supported by a narrative that justifies its inclusion. The entries were then assembled into a coherent sequence and returned to contributors for a round-robin review.
KW - Analytical atomic spectrometry
KW - Spectroscopy
KW - Instrumental analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621588
DO - https://doi.org/10.1177/00037028241263567
SN - 1943-3530
VL - 78
SP - 1
EP - 456
PB - Sage
CY - London
AN - OPUS4-62158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Schukar, Marcus
T1 - Humidity response of optical fibres with hygroscopic coatings and its temperature dependence
N2 - Optical fibres with hygroscopic coatings are widely used in structural health monitoring to acquire the humidity information. Water absorption-induced coating expansion leads to a strain change in the silica fibre, which can be measured by point and distributed strain fibre sensors and used to quantify the environmental humidity. In this paper, the strain transfer from the coating to the fibre is described by both 1D and 3D models. The impact of the coating property on the humidity induced strain is theoretically analysed. Since the properties of the sensing fibre are temperature-dependent, the humidity response obtained by the strain-based approach may change under different thermal conditions. The humidity response of fibres with different polyimide coatings is characterized by a commercial optical frequency domain reflectometer under different temperature conditions. The experimental results confirm the temperature dependence of the humidity response as the sensitivity of all the tested fibres decreases as the temperature increases.
KW - Rayleigh scattering
KW - Humidity sensor
KW - Optical fibre sensors
KW - Optical frequency domain reflectometer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629735
DO - https://doi.org/10.1088/2515-7647/adc85f
VL - 7
IS - 2
SP - 1
EP - 11
PB - IOP Publishing Ltd
CY - Bristol, UK
AN - OPUS4-62973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Chruscicki, Sebastian
A1 - Schukar, Marcus
A1 - Münzenberger, Sven
A1 - Krebber, Katerina
T1 - Application of Intensity-Based Coherent Optical Time Domain Reflectometry to Bridge Monitoring
N2 - Although distributed fiber sensing techniques have been widely used in structural health monitoring, the measurement results of bridge monitoring, particularly under destructive testing, have rarely been reported. To the best of our knowledge, this paper is the first report of distributed vibration measurement results, which we obtained during a three-day destructive test on an abolished bridge. A coherent optical time domain reflectometry (COTDR) was used to acquire the vibration information while the bridge was being sawed. The obtained signal was analyzed in time and frequency domain. Some characteristics of the sawing-induced vibration were retrieved by the short-time Fourier transform; the vibration exhibited several high frequency components within the measured range up to 20 kHz and all the components appeared in the same time slot. Some unexpected signals were also detected. Thorough analysis showed that they are quite different from the sawing-induced vibration and are believed to originate from internal damage to the bridge (probably the occurrence of cracks).
KW - Destructive testing
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Distributed acoustic sensing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547451
DO - https://doi.org/10.3390/s22093434
VL - 22
IS - 9
SP - 3434
PB - MDPI
AN - OPUS4-54745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krenek, S.
A1 - Eisermann, R.
A1 - Failleau, G.
A1 - Lu, Xin
A1 - Thomas, P.
A1 - Kjeldsen, H.
A1 - Anhalt, K.
T1 - Fibre-optic thermometry to support the clean energy transition
N2 - The measurement and control of temperature plays a key role in achieving the European Green Deal targets for a low carbon energy system. Fibre-optic thermometry is an emerging technology that can improve temperature measurement in extreme environments for energy providers and industry due to its distributed sensing and immunity to electromagnetic fields. Various applications for optimisation and monitoring in the energy sector are described, covering the whole range from energy generation to transmission and consumption. However, fibre-optic thermometers have cross sensitivities to other quantities (e.g., strain and humidity) and ageing effects that need to be investigated, quantified and minimised to obtain traceable and reliable measurements. This is particularly important so that applications in critical infrastructure can benefit from future measurements that are not possible with conventional sensors. The European INFOTherm project aims to overcome the limitations that currently prevent the widespread use of fibre-optic thermometry by creating a dedicated European metrology infrastructure for research, development and calibration. First results on measurement uncertainty, improvement of measurement techniques and practical field tests are presented.
KW - Industrial processes optimisation
KW - Fibre-optic thermometry
KW - Distributed temperature sensing
KW - Traceability
KW - Thermal energy storage
KW - Electrical grid resilience
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640075
DO - https://doi.org/10.1515/teme-2025-0044
SN - 2196-7113
VL - 92
IS - 9-10
SP - 392
EP - 405
PB - De Gruyter Brill
AN - OPUS4-64007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, J.
A1 - Zhang, S.
A1 - Yao, J.
A1 - Guo, Z.
A1 - Osenberg, M.
A1 - Hilger, A.
A1 - Markötter, Henning
A1 - Wilde, F.
A1 - Manke, I.
A1 - Zhang, X.
A1 - Sun, F.
A1 - Cui, G.
T1 - Synergistic Effect of CO2 in Accelerating the Galvanic Corrosion of Lithium/Sodium Anodes in Alkali Metal−Carbon Dioxide Batteries
N2 - Rechargeable alkali metal−CO2 batteries, which combine high theoretical energy density and environmentally friendly CO2 fixation ability, have attracted worldwide attention. Unfortunately, their electrochemical performances are usually inferior for practical applications. Aiming to reveal the underlying causes, a combinatorial usage of advanced nondestructive and postmortem characterization tools is used to intensively study the failure mechanisms of Li/Na−CO2 batteries. It is found that a porous interphase layer is formed between the separator and the Li/Na anode during the overvoltage rising and battery performance decaying process. A series of control experiments are designed to identify the underlying mechanisms dictating the observed morphological evolution of Li/Na anodes, and it is found that the CO2 synergist facilitates Li/Na chemical corrosion, the process of which is further promoted by the unwanted galvanic corrosion and the electrochemical cycling conditions. A detailed compositional analysis reveals that the as-formed interphase layers under different conditions are similar in species, with the main differences being their inconsistent quantity. Theoretical calculation results not only suggest an inherent intermolecular affinity between the CO2 and the electrolyte solvent but also provide the most thermodynamically favored CO2 reaction pathways. Based on these results, important implications for the further development of rechargeable alkali metal−CO2 batteries are discussed. The current discoveries not only fundamentally enrich our knowledge of the failure mechanisms of rechargeable alkali metal−CO2 batteries but also provide mechanistic directions for protecting metal anodes to build high-reversible alkali metal−CO2 batteries.
KW - Alkali metal batteries
KW - Synchrotron X-ray computed tomography
KW - Lithium/sodium−carbon dioxide batteries
KW - Battery failure mechanisms
KW - Alkali metal anodes
PY - 2024
DO - https://doi.org/10.1021/acsnano.4c02329
SP - 1
EP - 16
AN - OPUS4-59922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, X.
A1 - Zhang, S.
A1 - Lu, J.
A1 - Tang, F.
A1 - Dong, K.
A1 - Yu, Z.
A1 - Hilger, A.
A1 - Osenberg, M.
A1 - Markötter, Henning
A1 - Wilde, F.
A1 - Zhang, S.
A1 - Zhao, J.
A1 - Xu, G.
A1 - Manke, I.
A1 - Sun, F.
A1 - Cui, G.
T1 - Unveiling the Electro-Chemo-Mechanical Failure Mechanism of Sodium Metal Anodes in Sodium–Oxygen Batteries by Synchrotron X-Ray Computed Tomography
N2 - Rechargeable sodium–oxygen batteries (NaOBs) are receiving extensive research interests because of their advantages such as ultrahigh energy density and cost efficiency. However, the severe failure of Na metal anodes has impeded the commercial development of NaOBs. Herein, combining in situ synchrotron X-ray computed tomography (SXCT) and other complementary characterizations, a novel electro-chemo-mechanical failure mechanism of sodium metal anode in NaOBs is elucidated. It is visually showcased that the Na metal anodes involve a three-stage decay evolution of a porous Na reactive interphase layer (NRIL): from the initially dot-shaped voids evolved into the spindle-shaped voids and the eventually-developed ruptured cracks. The initiation of this three-stage evolution begins with chemical-resting and is exacerbated by further electrochemical cycling. From corrosion science and fracture mechanics, theoretical simulations suggest that the evolution of porous NRIL is driven by the concentrated stress at crack tips. The findings illustrate the importance of preventing electro-chemo-mechanical degradation of Na anodes in practically
rechargeable NaOBs.
KW - Synchrotron radiation
KW - X-ray imaging
KW - NaO-battery
PY - 2024
DO - https://doi.org/10.1002/adfm.202402253
SN - 1616-301X
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-59820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Becker, S.
A1 - Lu, Z.
A1 - Leinitz, Sarah
A1 - Schmidt, Wolfram
A1 - Stephan, D.
A1 - von Klitzing, R.
ED - Mechtcherine, V.
ED - Khayat, K.
ED - Secrieru, E.
T1 - Particle Interactions in Silica Systems in Presence of Superplasticizer
N2 - The flowability of cement paste is of great importance in today’s construction industry and is influenced by additives such as superplasticizers (SP). One type of SPs are polycarboxylate ether type SPs. These additives electrostatically bind with the negatively charged carboxylic groups at the backbone to the positively charged clinker phases.
To model positively charged clinker phases with adsorbed SP, silicon Wafers are pre-coated with cationic polyethylenimine (PEI) and SP is adsorbed onto the coated surface (Si/PEI/SP). Two different polycarboxylate ether type (PCE) SP are compared – one for ready-mix concrete and one for precast concrete. In this preliminary study the interaction forces between Si/PEI/SP surface and a silica microsphere (colloidal probe) are investigated under mild physico-chemical conditions (pH *6, ion concentration <10−5 M) using Colloidal Probe Atomic Force Microscopy (CP-AFM).
The interaction force between the model surfaces is attractive for low concentration of SP. The force changes from attractive to repulsive by increasing amount of SP. The force upon approach reveals a biexponential behavior. The exponential decay at large and short surface separations are attributed to electrostatic and steric interactions, respectively. The steric forces of the SP for ready-mix concrete show a steeper onset than the SP for precast concrete.
The quantification of these interaction forces will be compared to rheological measurements of similar systems. Furthermore, the parameters will be changed to better approach the conditions in real systems, i.e. higher pH and ionic strength. This helps to understand how the forces on the nanoscale influence the macroscopic rheology.
KW - Interfacial forces
KW - Silica beads
KW - Superplasticizer
KW - AFM
PY - 2019
SN - 978-3-030-22565-0
DO - https://doi.org/10.1007/978-3-030-22566-7
SN - 2211-0844
VL - 23
SP - 571
EP - 579
PB - Springer
ET - 1
AN - OPUS4-49183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ji, Y.
A1 - Becker, S.
A1 - Lu, Z.
A1 - Mezhov, Alexander
A1 - von Klitzing, R.
A1 - Schmidt, Wolfram
A1 - Stephan, D.
T1 - Effect of resting time on rheological properties of glass bead suspensions - Depletion and bridging force among particles
N2 - The effect of resting time on the rheological properties of cement suspensions is generally explained by early formed structure and overconsumption of polycarboxylate superplasticizers (PCEs). In this paper, we propose that the influence of resting time on the rheological properties is closely related to size variation of non-absorbed PCE. To identify this, glass bead suspensions were prepared with various amounts of PCE and ionic solution, and their rheological properties were evaluated at various times. We found that the yield stress increases with time at higher PCE concentrations and higher ionic strength solutions. Adsorbed PCE during resting tends to bridge the particles rather than disperse them. In addition, it was found that hydrodynamic radius of PCE increased with resting time, and depletion forces resulting from non-absorbed PCE size changes correlate well with the increased yield stress.
KW - Depletion force
KW - Ionic stregth
KW - PCE
KW - Rheology
KW - Resting time
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587193
DO - https://doi.org/10.1111/jace.19469
SN - 0002-7820
SN - 1551-2916
VL - 107
IS - 1
SP - 624
EP - 639
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-58719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z.
A1 - Haist, M.
A1 - Ivanov, D.
A1 - Jakob, C.
A1 - Jansen, D.
A1 - Leinitz, Sarah
A1 - Link, J.
A1 - Mechtcherine, V.
A1 - Neubauer, J.
A1 - Plank, J.
A1 - Schmidt, Wolfram
A1 - Schilde, C.
A1 - Schröfl, C.
A1 - Sowoidnich, T.
A1 - Stephan, D.
T1 - Characterization data of reference cement CEM I 42.5 R used for Priority Program DFG SPP 2005 “Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials”
N2 - A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The data were collected based on tests conducted by nine research groups involved in this cooperative program. For all data received, the mean values and the corresponding errors were calculated. The results shall be used for the ongoing research within the priority program.
KW - Portland cement
KW - Characterization
KW - DFG SPP 2005
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500849
DO - https://doi.org/10.1016/j.dib.2019.104699
SN - 2352-3409
VL - 27
SP - 104699
PB - Elsevier Inc.
AN - OPUS4-50084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Christensen, J.
A1 - Thomas, P.
A1 - Failleau, G.
A1 - Eisermann, R.
A1 - Hicke, Konstantin
A1 - Krenek, S.
T1 - Fiber artefact for performance evaluation of time domain distributed fiber sensor interrogators
N2 - Distributed fiber sensing (DFS) is a powerful tool for structural health monitoring (SHM), allowing continuous and seamless measurements of temperature and strain along the fiber. The spatial accuracy of a DFS interrogator, as a key parameter of the system, is vital for precisely locating structural perturbations or defects. Its evaluation and calibration methods however attract little attention. A fiber optic artefact based on a fiber loop is developed to evaluate distance accuracy and signal quality for both self-developed and commercial sensing systems based on Rayleigh, Raman, and Brillouin scattering effects, respectively. The measured distance is corrected to remove the influence of the pulse width. Additionally, the obtained SNRs are compared for different loop trips and pulse widths, assisting to assess signal quality for SHM applications.
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Distributed temperature sensing
KW - Fiber artefact
KW - Spatial correction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648966
DO - https://doi.org/10.1088/1361-6501/ae214e
VL - 36
IS - 11
SP - 1
EP - 10
PB - IOP Publishing Ltd
CY - Bristol, UK
AN - OPUS4-64896
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, W.-H.
A1 - Qin, J.
A1 - Lu, D.-G.
A1 - Thöns, Sebastian
A1 - Havbro Faber, M.
T1 - Vol-informed decision-making for SHM system arrangement
N2 - Structural health monitoring systems have been widely implemented to provide real-time continuous data support and to ensure structural safety in the context of structural integrity management. However, the quantification of the potential benefits of structural health monitoring systems has not yet attracted widespread attention. At the same time, there is an urgent need to develop strategies, such as optimizing the monitoring period, monitoring variables, and other factors, to maximize the potential benefits of structural health monitoring systems. Considering the continuity of structural health monitoring information, a framework is developed in this article to support decision-making for structural Health monitoring systems arrangement in the context of structural integrity management, which integrates the concepts of value of information and risk-based inspection planning based on an approach which utilizes a conjugate prior probability distribution for updating of the probabilistic models of structural performances based on structural health Monitoring information. An example considering fatigue degradation of steel structures is investigated to illustrate the application of the proposed framework. The considered example shows that the choice of monitoring variables, the Monitoring period, and the monitoring quality may be consistently optimized by the application of the proposed framework and approach. Finally, discussions and conclusions are provided to clarify the potential benefits of the proposed Framework with a special view to practical applications of structural health monitoring systems.
KW - Value of information
KW - Structural health monitoring systems arrangement strategy
KW - Structural integrity management
KW - Rskbased inspection
KW - Structural health monitoring information model
PY - 2020
DO - https://doi.org/10.1177/1475921720962736
SN - 1475-9217
VL - 21
IS - 1
SP - 37
EP - 58
PB - SAGE Journals
CY - USA
AN - OPUS4-53064
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Holm, O.
A1 - Leube, Peter
A1 - Vogel, Christian
A1 - Kennedy, E.
A1 - Stockenhuber, M.
A1 - Lucas, J.
A1 - Truong, T.
A1 - Rappé, A.
A1 - Lu, W.
A1 - Blotevogel, J.
T1 - Thermische Zerstörung von PFAS in der Sondermüllverbrennung: Einfluss von Temperatur und PFAS-Konzentration
N2 - Aufgrund ihrer einzigartigen molekularen Beschaffenheit werden per- und polyfluorierte Alkylsubstanzen (PFAS) in vielen unterschiedlichen Produkten und Anwendungsgebieten eingesetzt. Da sie generell eine hohe Persistenz aufweisen und je nach individueller Struktur unterschiedlich mobil sind, sind sie mittlerweile in allen Umweltkompartimenten und ubiquitär nachzuweisen. Ihre potenzielle (ökologische) Toxizität birgt dabei erhebliche Umweltrisiken, weshalb PFAS in den letzten Jahren mehr und mehr in den Fokus von Umweltverbänden und -behörden gelangten. Gleichzeitig beschäftigen sich Forschungseinrichtungen mit der möglichst weitreichenden Entfernung aus der Umwelt sowie mit deren (anschließender) Zerstörung.
Im Projekt ER24-4073 „Untersuchung des thermischen Abbaus von PFAS in einer kommerziellen Großanlage zur Verbrennung gefährlicher Abfälle“, welches vom U.S. Department of Defense (DoD ) über das Strategic Environmental Research and Development Program (SERDP) gefördert wird, untersuchen deutsche, australische und amerikanische Partner die Behandlung von PFAS-haltigen Abfallströmen in einer großtechnischen Verbrennungsanlage, um die Einsatzbereitschaft, Machbarkeit und Sicherheit dieser Zerstörungsmethode zu demonstrieren.
T2 - Berliner Konferenz Abfallwirtschaft und Energie
CY - Berlin, Germany
DA - 28.01.2026
KW - Per- and polyfluoroalkyl substances (PFAS)
KW - Verbrennung
KW - Kontaminierter Boden
PY - 2026
SN - 978-3-911006-65-1
SP - 66
EP - 77
PB - TK Verlag
AN - OPUS4-65513
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z. C.
A1 - Haist, M.
A1 - Ivanov, D.
A1 - Jakob, C.
A1 - Jansen, D.
A1 - Schmid, M.
A1 - Kißling, P. A.
A1 - Leinitz, Sarah
A1 - Link, J.
A1 - Mechtcherine, V.
A1 - Neubauer, J.
A1 - Plank, J.
A1 - Schmidt, Wolfram
A1 - Schilde, C.
A1 - Schröfl, C.
A1 - Sowoidnich, T.
A1 - Stephan, D.
T1 - Characterization data of reference cement CEM III/A 42.5N used for priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials"
N2 - Two types of cements were selected as the reference cement in the priority program 2005 of the German Research Foundation (DFG SPP 2005). A thorough characterization of CEM I 42.5 R has been made in a recent publication. In this paper, the characterization data of the other reference cement CEM III/A 42.5 N are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The characterization data of the slag, which is the second main constituent of this specific cement besides the clinker, are presented independently. For all data received, the mean values and the corresponding errors were calculated. The data shall be used for the ongoing research within the priority program. Also, researchers from outside this priority program can benefit from these data if the same materials are used.
KW - Cement
KW - Slag
KW - Characterization
KW - DFG SPP 2005
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568980
DO - https://doi.org/10.1016/j.dib.2020.105524
SN - 2352-3409
VL - 30
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Leinitz, Sarah
A1 - Lu, Z.
A1 - Becker, S.
A1 - Stephan, D.
A1 - von Klitzing, R.
A1 - Schmidt, Wolfram
ED - Mechtcherine, V.
ED - Khayat, K.
ED - Secrieru, E.
T1 - Influence of different accelerators on the rheology and early hydration of cement paste
N2 - Special applications like pumping, spraying or printing of concrete require the precise adjustment of very specific rheological properties at different time steps during the casting process. Superplasticizers such as polycarboxylate ethers (PCE) can be used to obtain the required flowability, which, possibly in combination with additional rheology modifying admixtures, generate the required specified consistency. However, after the application, the concrete should change the rheological properties immediately in order to avoid deformations at rest. Therefore, the use of accelerators can be effective. Accelerators influence the hydration of cementitious materials, and thus the rheological properties over the course of time and the setting.
In this paper, the influence of different accelerators on the rheology and early hydration of cement paste as well as the interaction of accelerator and PCE are presented. Methods like rheometry, needle penetration tests and practical Tests like spread flow were applied. The used accelerators showed accelerating behavior on the cement pastes without and in the presence of PCE. At the same time an influence on the rheology could be observed. This effect was less in the mixes with PCE, especially at the highest water/cement ratio (w/c).
KW - Rheology
KW - Cement paste
KW - Accelerator
KW - Superplasticizer
KW - Setting
PY - 2019
SN - 978-3-030-22565-0
DO - https://doi.org/10.1007/978-3-030-22566-7
SN - 2211-0844
VL - 23
SP - 106
EP - 115
PB - Springer
ET - 1
AN - OPUS4-49139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Lu, Z.
A1 - Becker, S.
A1 - Leinitz, Sarah
A1 - von Klitzing, R.
A1 - Schmidt, Wolfram
A1 - Stephan, D.
ED - Mechtcherine, V.
ED - Khayat, K.
ED - Secrieru, E.
T1 - Rheological properties of silica beads in the presence of different polymers and electrolyte
N2 - Properties of interstitial liquid phase in cement paste, including the species and concentrations of polymers and ion etc., play an important role for the rheological properties of cementitious materials. In order to better understand their effect, an inert model substance, spherical silica beads (SBs) with defined surface and granulometry were used in the presence of electrolytes (CaCl2) and/or different polymers, including polycarboxylate superplasticizer (PCE) and polyethylene glycol (PEG). It was found the presence of Ca2+ greatly increases the viscosity and yield stress of silica beads paste (SBP), which is proportional to the [Ca2+]. For the effect of PCE, the addition of PCE is beneficial to the flowability of SBP, but a high dosage of PCE leads to a reversal effect. Furthermore, the yield stress firstly increases and then decreases with increasing [Ca2+] under the same dosage of PCE. The addition of PEG always increases the yield stress of SBP, regardless of the ion concentration and the presence or not of PCE.
KW - Rheological properties
KW - Ions
KW - Superplasticizer
KW - Silica beads
PY - 2019
SN - 978-3-030-22565-0
SN - 978-3-030-22566-7
DO - https://doi.org/10.1007/978-3-030-22566-7_72
SN - 2211-0844
VL - 23
SP - 619
EP - 627
PB - Springer
ET - 1
AN - OPUS4-49185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z.
A1 - Becker, S.
A1 - Leinitz, Sarah
A1 - Schmidt, Wolfram
A1 - von Klitzing, R.
A1 - Stephan, D.
T1 - Interaction of Different Charged Polymers with Potassium Ions and Their Effect on the Yield Stress of Highly Concentrated Glass Bead Suspensions
N2 - The interaction of different charged polymers, namely anionic polycarboxylate
superplasticizer (PCE) and neutral polyethylene glycol (PEG) with potassium ions, and their effect on the yield stress of highly concentrated glass bead suspension (GBS), were studied under different concentrations of potassium ions ([K+]). It was found that, compared to the neutral PEG, the negatively charged PCE can be adsorbed on glass beads (GB), and then decreases the yield stress of GBS. The increasing concentration of free polymer in the interstitial liquid phase with the increased polymer dosage leads to the higher yield stress of GBS, which may be caused by the higher Depletion force. In addition, this effect is also related to the charge density of the polymer and the [K+] in the solution. Along with the increase in [K+], the yield stress of GBS increases significantly with the addition of PCE, but this cannot be observed with PEG, which indicates that potassium ions can interact with negatively charged PCE instead of the neutral PEG. At last, the interparticle Forces between two single GB with adsorbed PCE in solutions containing [K+] and PCE were measured by colloidal probe atomic force microscopy to better understand the interaction of the charged polymer with counterions.
KW - Yield stress
KW - Free polymer
KW - Charge density
KW - Depletion force
KW - Potassium ions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506015
DO - https://doi.org/10.3390/ma13071490
SN - 1996-1944
VL - 13
IS - 7
SP - 1490, 1
EP - 1490, 16
PB - MDPI
AN - OPUS4-50601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Nils
A1 - Dayani, Shahabeddin
A1 - Markötter, Henning
A1 - Schmidt, Anita
A1 - Kowal, J.
A1 - Lu, Y.
A1 - Krug von Nidda, Jonas
A1 - Bruno, Giovanni
T1 - Visualization of stepwise electrode decomposition in a nail penetrated commercial lithium-ion cell using low-temperature synchrotron X-ray computed tomography
N2 - The transition towards zero carbon emissions in power generation hinges on the integration of efficient electrical energy storage systems, with lithium-ion batteries (LIBs) positioned as a pivotal technology. While generally safe, deviations in their operational guidelines due to manufacturing defects or misuse can lead to critical safety concerns, notably thermal runaway (TR) events. Internal short circuits (ISCs) are primary initiators of TR within LIBs. For abuse testing, ISCs are often triggered by nail penetration. This study explores the morphological changes and mechanisms underlying ISC-induced TR in LIBs using operando synchrotron X-ray computed tomography (SXCT) at subzero temperatures. A novel cryogenic setup was developed to control a stepwise temperature increase in the damaged sample while monitoring electrochemical characteristics and simultaneously enabling acquisition of high-resolution SXCT images. The findings reveal that conducting nail penetration at minus 80°C prevents immediate TR, enabling detailed analysis of subsequent structural and electrochemical behavior during controlled thawing. Thus, the initiation of TR processes at localized ISC sites has been observed, evidenced by voltage fluctuations and morphological changes, such as cathode material cracking and decomposition. These results underscore the importance of temperature control in mitigating TR risks and provide critical insights into the internal dynamics of LIBs under abusive conditions. The developed cryogenic SXCT methodology offers a powerful tool for non-destructive, high-resolution investigation of battery failure mechanisms, contributing to the enhancement of LIB safety.
KW - Tomography
KW - X-ray imaging
KW - Lithium-ion battery
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611327
DO - https://doi.org/10.1016/j.jpowsour.2024.235472
VL - 623
SP - 1
EP - 10
PB - Elsevier
CY - New York, NY
AN - OPUS4-61132
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Kun
A1 - Schukar, Marcus
A1 - Hicke, Konstantin
A1 - Lu, Xin
T1 - Effect of humidity on fiber-optic temperature sensing
N2 - This study investigates the influence of ambient humidity on the temperature sensitivity, measurement accuracy, and uncertainty of optical fibers with different coatings, using a Rayleigh-based distributed sensing technique. Polymer-coated fibers (acrylate and polyimide) and metal-coated fibers (copper and gold) were tested under controlled humidity (30%–90% RH) and temperature (20–60 °C) conditions. Rayleigh-based measurements revealed a slight but consistent decrease in temperature sensitivity with increasing humidity for all polymer-coated fibers, attributed to humidity-induced changes in coating stiffness and strain transfer. In contrast, metal-coated fibers exhibited humidity-independent behavior and superior stability. These findings highlight the non-negligible role of ambient humidity in fiber-optic temperature sensing, particularly in Rayleigh-based systems using hygroscopic coatings. The results provide practical guidance for fiber and coating selection in humid environments and offer broader insight into humidity–strain–temperature coupling mechanisms relevant to other fiber-optic sensing mechanisms.
KW - Distributed sensing
KW - Humidity effect
KW - Temperature sensing
KW - Optical fiber coatings
KW - Temperature uncertainty
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650040
DO - https://doi.org/10.1016/j.measurement.2025.119905
SN - 0263-2241
VL - 261
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-65004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, H.
A1 - Song, W.
A1 - Gröninger, Delia
A1 - Zhang, L.
A1 - Lu, Y.
A1 - Chan, K. S.
A1 - Zhou, Z.
A1 - Rurack, Knut
A1 - Shen, Z.
T1 - Real-time monitoring of newly acidified organelles during autophagy enabled by reaction-based BODIPY dyes
N2 - Real-time monitoring of newly acidified organelles during autophagy in living cells is highly desirable for a better understanding of intracellular degradative processes. Herein, we describe a reaction-based boron dipyrromethene (BODIPY) dye containing strongly electron-withdrawing diethyl 2-cyanoacrylate groups at the α-positions. The probe exhibits intense red fluorescence in acidic organelles or the acidified cytosol while negligible fluorescence in other regions of the cell. The underlying mechanism is a nucleophilic reaction at the central meso-carbon of the indacene core, resulting in the loss of π-conjugation entailed by dramatic spectroscopic changes of more than 200 nm between its colorless, non-fluorescent leuco-BODIPY form and its red and brightly emitting form. The reversible transformation between red fluorescent BODIPY and leuco-BODIPY along with negligible cytotoxicity qualifies such dyes for rapid and direct intracellular lysosome imaging and cytosolic acidosis detection simultaneously without any washing step, enabling the real-time monitoring of newly acidified organelles during autophagy.
KW - Autophagy
KW - BODIPY
KW - Fluorescence
KW - Lysosome
KW - Real-time imaging
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498358
UR - https://www.nature.com/articles/s42003-019-0682-1
DO - https://doi.org/10.1038/s42003-019-0682-1
SN - 23993642
VL - 2
SP - 442
PB - Nature Research
CY - London
AN - OPUS4-49835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duewer, D. L.
A1 - Murray, J. A.
A1 - Wood, L. J.
A1 - Wise, S. A.
A1 - Hein, Sebastian
A1 - Koch, Matthias
A1 - Philipp, Rosemarie
A1 - Werneburg, Martina
A1 - Hackenberg, R.
A1 - Polzer, J.
A1 - Avila, M. A.
A1 - Serrano, V.
A1 - Kakoulides, E.
A1 - Alexopoulos, C.
A1 - Giannikopoulou, P.
A1 - Gui, E. M.
A1 - Lu, T.
A1 - Teo, T. L.
A1 - Hua, T.
A1 - Dazhou, C.
A1 - Chunxin, L.
A1 - Changjun, Y.
A1 - Hongmei, L.
A1 - Nammoonnoy, J.
A1 - Sander, L. C.
A1 - Lippa, K.
A1 - Quinn, L.
A1 - Swiegelaar, C.
A1 - Fernandes-Whaley, M.
A1 - Gören, A. C.
A1 - Gökcen, T.
T1 - CCQM-K95.1 Low-polarity analytes in a botanical matrix: Polycyclic aromatic hydrocarbons (PAHs) in tea
N2 - Extraction, chromatographic separation, and quantification of low-concentration organic compounds in complex matrices are core challenges for reference material producers and providers of calibration services. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2014 the Organic Analysis Working Group (OAWG) initiated CCQM-K95.1 "Low-Polarity Analytes in a Botanical Matrix: Polycyclic Aromatic Hydrocarbons (PAHs) in Tea". This was a follow-on comparison from CCQM-K95 which was completed in 2014.
The polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) are considered priority pollutants by U.S. Environmental Protection Agency and are regulated contaminants in food, pose chromatographic separation challenges, and for which exist well-characterized measurement procedures and standard materials. BaA and BaP in a smoked tea were therefore selected as representative target measurands for CCQM-K95.1. Ten NMIs participated in CCQM-K95.1. The consensus summary mass fractions for the two PAHs are in the range of (50 to 70) ng/g with relative standard deviations of (6 to 10) %.
Successful participation in CCQM K95.1 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molar mass of 100 g/mol to 500 g/mol and having polarity pKow −2, in a botanical matrix ranging in mass fraction from 10 ng/g to 1000 ng/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, (3) extraction of analytes of interest from the matrix, (4) cleanup and separation of analytes of interest from interfering matrix or extract components, and (5) separation and quantification using gas chromatography or liquid chromatography.
KW - Benz[a]anthracene (BaA)
KW - Benzo[a]pyrene (BaP)
KW - Gas chromatography (GC)
KW - Isotope dilution (ID)
KW - Liquid chromatography (LC)
KW - Mass spectrometry (MS)
KW - Polycyclic aromatic hydrocarbon (PAH)
KW - Yerba mate tea
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471430
DO - https://doi.org/10.1088/0026-1394/56/1A/08002
SN - 0026-1394
SN - 1681-7575
VL - 56
IS - 1 A
SP - 08002, 1
EP - 89
PB - IOP Science
AN - OPUS4-47143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wu, Y.
A1 - Lu, X.
A1 - Cho, J.I.S.
A1 - Rasha, L.
A1 - Whiteley, M.
A1 - Neville, T. P.
A1 - Ziesche, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Manke, I.
A1 - Zhang, X.
A1 - Shearing, P. R.
A1 - Brett, D. J. L.
T1 - Multi-length scale characterization of compression on metal foam flow-field based fuel cells using X-ray computed tomography and neutron radiography
N2 - The mechanical compression of metal foam flow-field based polymer electrolyte fuel cells (PEFCs) is critical in determining the interfacial contact resistance with gas diffusion layers (GDLs), reactant flow and water management.
The distinct scale between the pore structure of metal foams and the entire flow-field warrant a multilength scale characterization that combines ex-situ tests of compressed metal foam samples and in-operando analysis of operating PEFCs using X-ray computed tomography (CT) and neutron radiography. An optimal ‘medium’ compression was found to deliver a peak power density of 853 mW/cm². The X-ray CT data indicates that the compression process significantly decreases the mean pore size and narrows the pore size distribution of metal foams. Simulation results suggest compressing metal foam increases the pressure drop and gas velocity, improving the convective liquid water removal. This is in agreement with the neutron imaging results that demonstrates an increase in the mass of accumulated liquid water with minimum compression compared to the medium and maximum compression cases. The results show that a balance between Ohmic resistance, water removal capacity and parasitic power is imperative for the optimal performance of metal foam based PEFCs.
KW - Fuel cell
KW - Compression effect
KW - Metal foam microstructure
KW - Neutron radiography
KW - X-ray CT
PY - 2021
DO - https://doi.org/10.1016/j.enconman.2020.113785
VL - 239
SP - 10
EP - 113785
PB - Elsevier Ltd.
AN - OPUS4-53842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duewer, D. L.
A1 - Sander, L. C.
A1 - Wise, S. A.
A1 - Philipp, Rosemarie
A1 - Hein, Sebastian
A1 - Hackenberg, R.
A1 - Polzer, J.
A1 - Avila, M. A.
A1 - Serrano, V.
A1 - Kakoulides, E.
A1 - Alexopoulos, C.
A1 - Giannikopoulou, P.
A1 - Chan, P.
A1 - Lee, H.
A1 - Tang, H.
A1 - Tang, P.
A1 - Yip, Y.
A1 - Lu, T.
A1 - Cheow, P. S.
A1 - Teo, T. L.
A1 - Sega, M.
A1 - Rolle, F.
A1 - Baek, S.
A1 - Kim, B.
A1 - Lee, S.
A1 - Cabillic, J.
A1 - Fallot, C.
A1 - Hua, T.
A1 - Dazhou, C.
A1 - Changjun, Y.
A1 - Chunxin, L.
A1 - Hongmei, L.
A1 - Lippa, K.
A1 - Itoh, N.
A1 - Quinn, L.
A1 - Prevoo-Franzsen, D.
A1 - Fernandes-Whaley, M.
A1 - Gören, A. C.
A1 - Gökcen, T.
A1 - Gündüz, S.
A1 - Krylov, A.
A1 - Mikheeva, A.
A1 - Baldan, A.
A1 - van der Hout, J. W.
A1 - van der Veen, A. M. H.
T1 - CCQM-K131 Low-polarity analytes in a multicomponent organic solution: Polycyclic aromatic hydrocarbons (PAHs) in acetonitrile
N2 - Solutions of organic analytes of known mass fraction are typically used to calibrate the measurement processes used to determine these compounds in matrix samples. Appropriate value assignments and uncertainty calculations for calibration solutions are critical for accurate measurements. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2015 the Organic Analysis Working Group (OAWG) sponsored CCQM-K131 "Low-Polarity Analytes in a Multicomponent Organic Solution: Polycyclic Aromatic Hydrocarbons (PAHs) in Acetonitrile".
Polycyclic aromatic hydrocarbons (PAHs) result from combustion sources and are ubiquitous in environmental samples. The PAH congeners, benz[a]anthracene (BaA), benzo[a]pyrene (BaP), and naphthalene (Nap) were selected as the target analytes for CCQM-K131. These targets span the volatility range of PAHs found in environmental samples and include potentially problematic chromatographic separations. Nineteen NMIs participated in CCQM-K131. The consensus summary mass fractions for the three PAHs are in the range of (5 to 25) μg/g with relative standard deviations of (2.5 to 3.5) %.
Successful participation in CCQM-K131 demonstrates the following measurement capabilities in determining mass fraction of organic compounds of moderate to insignificant volatility, molar mass of 100 g/mol up to 500 g/mol, and polarity pKow < −2 in a multicomponent organic solution ranging in mass fraction from 100 ng/g to 100 μg/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, and (3) separation and quantification using gas chromatography or liquid chromatography.
KW - Benz[a]anthracene (BaA)
KW - Benzo[a]pyrene (BaP)
KW - Gas chromatography (GC)
KW - Isotope dilution (ID)
KW - Liquid chromatography (LC)
KW - Mass spectrometry (MS)
KW - Naphthalene (Nap)
KW - Organic calibration solution
KW - Polycyclic aromatic hydrocarbon (PAH)
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471442
DO - https://doi.org/10.1088/0026-1394/56/1A/08003
SN - 0026-1394
SN - 1681-7575
VL - 56
IS - 1A
SP - 08003, 1
EP - 102
PB - IOP Science
AN - OPUS4-47144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Trogadas, P.
A1 - Cho, J. I. S.
A1 - Rasha, L.
A1 - Lu, X.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Manke, I.
A1 - Shearing, P. R.
A1 - Brett, D. J. L.
A1 - Coppens, M. O.
T1 - A nature-inspired solution for water management in flow fields for electrochemical devices
N2 - A systematic, nature-inspired chemical engineering approach is employed to solve the issue of flooding in electrochemical devices. The mechanism of passive water transport utilized by lizards living in arid environments is leveraged to design flow-fields with a microchannel structure on their surface, through which capillary pressure rapidly removes the water generated in the electrochemical device. This water management strategy is implemented in proton exchange membrane fuel cells (PEMFCs) with a lunginspired flow-field, which ensures uniform distribution of reactants across the catalyst layer. Jointly, this nature-inspired approach results in flood-free, stable operation at 100% RH and a B60% increase in current (B1.9 A cm-2) and peak power density (B650 mW cm−2) compared to current PEMFCs with a flood-prone, serpentine flow-field (B0.8 A cm-2 and 280 mW cm-2, respectively). This significant advance allows for PEMFC operation at fully humidified conditions.
KW - Neutron imaging
KW - X-ray tomography
KW - Fuel cell
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596662
DO - https://doi.org/10.1039/d3ee03666a
VL - 17
SP - 2007
EP - 2017
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
T1 - Error suppression in wavelength scanning coherent optical time domain reflectometry by polarization diversity detection
N2 - Wavelength scanning coherent optical time domain reflectometry (WS-COTDR) is a popular distributed fiber sensing technique that quantifies environmental changes based on the frequency shift of Rayleigh reflection spectra which are usually obtained by cross correlation. This method can cause large errors due to the spikes in the spectrum caused by the random interference of the Rayleigh backscattered light and the uncorrelated section in the reflection spectrum. Polarization diversity detection is applied to suppress this type of error. Two orthogonally polarized components of the Rayleigh backscattered light are detected in a single sensing system and processed separately by cross correlation. The correlation spectra of the two polarizations are averaged to determine the frequency shift, effectively mitigating the large error. Meanwhile, the polarization dependence helps avoid the large errors caused by Fresnel reflection and restrain null sensitivity positions, where the frequency shift is difficult to be determined due to the similarity of the spectra. The sensing performance improvement is experimentally validated, and the proposed system is tested in the field to monitor traffic along a busy street in Berlin, demonstrating its functionality and feasibility in practice.
KW - Traffic monitoring
KW - Coherent optical time domain reflectometry
KW - Distributed fiber sensing
KW - Polarization diversity detection
KW - Optical fiber sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630320
DO - https://doi.org/10.1016/j.measurement.2025.117733
SN - 1873-412X
VL - 253
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-63032
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Königsbauer, Korbinian
A1 - Hicke, Konstantin
T1 - Improved phase retrieval method for system simplification or fading suppression in interferometer-based φOTDR systems
N2 - Phase sensitive optical time domain reflectometry (φOTDR) systems based on different types of interferometers for phase retrieval typically require two or three photodetectors to record the outputs from the interferometer. A novel signal processing principle is proposed for phase retrieval by taking the difference between two outputs as the quadrature component and reconstructing the in-phase component via Hilbert transformation of the Q component for IQ demodulation. Thus, only one balanced photodetector or two standard photodetectors are need, reducing system complexity and data volume. This principle can also be used to suppress fading effect for the traditional three-detector φOTDR systems by selecting optimal phases across detector pairs. Experiments with a φOTDR systems based on an imbalanced Mach-Zehnder interferometer validate the feasibility of this method and demonstrate a high fading suppression of about 90%.
KW - Phase retrieval
KW - Distributed fiber sensing
KW - Structural health monitoring
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652630
DO - https://doi.org/10.1364/OE.580984
SN - 1094-4087
VL - 33
IS - 26
SP - 54733
EP - 54746
PB - Optica Publishing Group
AN - OPUS4-65263
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaiser, J.
A1 - Szczerba, Wojciech
A1 - Riesemeier, Heinrich
A1 - Reinholz, Uwe
A1 - Radtke, Martin
A1 - Albrecht, M.
A1 - Lu, Y.
A1 - Ballauff, M.
T1 - The structure of AuPd nanoalloys anchored on spherical polyelectrolyte brushes determined by x-ray absorption spectroscopy
N2 - Well-defined and facetted bimetallic gold–palladium nanoalloys have been synthesized and anchored in spherical polyelectrolyte brushes (SPB) as composite particles (AuPd@SPB). These particles are better catalysts in aqueous phase than the pure metals. The atomistic arrangement of these nanoalloys has been analysed by extended X-ray absorption fine structure (EXAFS) spectroscopy at the Au–L3 and the Pd–K absorption edge. The samples with high amounts of gold appear as almost statistically mixed random alloys. Alloy compositions with less gold show slight enrichment of Pd at the surface of the particle. In addition, signals of non-metallic palladium appear at the Pd–K edge which indicate the presence of the Pd2+ species in addition to metallic palladium. The relation of these structural features to the catalytic activity is discussed.
KW - EXAFS
KW - Nanoalloys
KW - Gold
KW - Palladium
KW - K-edge
KW - L3-edge
KW - HR-TEM
KW - Synchrotron radiation
KW - BAMline
PY - 2013
DO - https://doi.org/10.1039/c3fd20132e
SN - 1359-6640
SN - 1364-5498
VL - 162
SP - 45
EP - 55
PB - Soc.
CY - Cambridge [u.a.]
AN - OPUS4-28300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -