@article{36800, abstract = {{Abstract. The miniaturisation of components leads to new demands on measurement systems. One of these is the resolution. As a volumetric analysis method and method of non-destructive testing, industrial X-ray computed tomography (XCT) has the ability to measure geometrical features and their corresponding dimensions without destroying them and can therefore be used for quality assurance. However, the concept of resolution is not trivial for XCT and has not yet been finally clarified. In particular, the interface structural resolution, the detectability of two surfaces facing each other after surface segmentation, faces a lack of a test specimen, a corresponding measurand and a reliable method. Simulation-based XCT investigations of a method to determine this type of resolution are presented in this article using the geometry of a test specimen that contains several radially arranged holes of the same size. The borehole diameters correspond to the distance between the holes to investigate the resolvability of surfaces and interfaces. The evaluation is based on mean and extreme values of grey value profiles between the individual boreholes of the reconstructed volume. It is shown that the geometrical detectability of the test specimen surface and interface can be extended by a reasonable choice of the threshold value for surface segmentation within a defined interval. With regard to the resolving capability, a distinction is made between assured detectability and possible detectability, as well as the threshold value used when using the ISO50 threshold for surface segmentation and measurement chain completion. }}, author = {{Busch, Matthias and Hausotte, Tino}}, issn = {{2194-878X}}, journal = {{Journal of Sensors and Sensor Systems}}, keywords = {{Electrical and Electronic Engineering, Instrumentation}}, number = {{1}}, pages = {{1--8}}, publisher = {{Copernicus GmbH}}, title = {{{Simulation-based investigation of the metrological interface structural resolution capability of X-ray computed tomography scanners}}}, doi = {{10.5194/jsss-12-1-2023}}, volume = {{12}}, year = {{2023}}, } @article{43457, abstract = {{The production of hydrogen and the utilization of biomass for sustainable concepts of energy conversion and storage require gas sensors that discriminate between hydrogen (H2) and carbon monoxide (CO). Mesoporous copper–ceria (Cu–CeO2) materials with large specific surface areas and uniform porosity are prepared by nanocasting, and their textural properties are characterized by N2 physisorption, powder XRD, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The oxidation states of copper (Cu+, Cu2+) and cerium (Ce3+, Ce4+) are investigated by XPS. The materials are used as resistive gas sensors for H2 and CO. The sensors show a stronger response to CO than to H2 and low cross-sensitivity to humidity. Copper turns out to be a necessary component; copper-free ceria materials prepared by the same method show only poor sensing performance. By measuring both gases (CO and H2) simultaneously, it is shown that this behavior can be utilized for selective sensing of CO in the presence of H2.}}, author = {{Baier, Dominik and Priamushko, Tatiana and Weinberger, Christian and Kleitz, Freddy and Tiemann, Michael}}, issn = {{2379-3694}}, journal = {{ACS Sensors}}, keywords = {{Fluid Flow and Transfer Processes, Process Chemistry and Technology, Instrumentation, Bioengineering}}, number = {{4}}, pages = {{1616 -- 1623}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Selective Discrimination between CO and H2 with Copper–Ceria-Resistive Gas Sensors}}}, doi = {{10.1021/acssensors.2c02739}}, volume = {{8}}, year = {{2023}}, } @article{45134, abstract = {{The aim of the present study was to investigate if the presence of anterior cruciate ligament (ACL) injury risk factors depicted in the laboratory would reflect at-risk patterns in football-specific field data. Twenty-four female footballers (14.9 ± 0.9 year) performed unanticipated cutting maneuvers in a laboratory setting and on the football pitch during football-specific exercises (F-EX) and games (F-GAME). Knee joint moments were collected in the laboratory and grouped using hierarchical agglomerative clustering. The clusters were used to investigate the kinematics collected on field through wearable sensors. Three clusters emerged: Cluster 1 presented the lowest knee moments; Cluster 2 presented high knee extension but low knee abduction and rotation moments; Cluster 3 presented the highest knee abduction, extension, and external rotation moments. In F-EX, greater knee abduction angles were found in Cluster 2 and 3 compared to Cluster 1 (p = 0.007). Cluster 2 showed the lowest knee and hip flexion angles (p < 0.013). Cluster 3 showed the greatest hip external rotation angles (p = 0.006). In F-GAME, Cluster 3 presented the greatest knee external rotation and lowest knee flexion angles (p = 0.003). Clinically relevant differences towards ACL injury identified in the laboratory reflected at-risk patterns only in part when cutting on the field: in the field, low-risk players exhibited similar kinematic patterns as the high-risk players. Therefore, in-lab injury risk screening may lack ecological validity.}}, author = {{Di Paolo, Stefano and Nijmeijer, Eline M. and Bragonzoni, Laura and Gokeler, Alli and Benjaminse, Anne}}, issn = {{1424-8220}}, journal = {{Sensors}}, keywords = {{Electrical and Electronic Engineering, Biochemistry, Instrumentation, Atomic and Molecular Physics, and Optics, Analytical Chemistry}}, number = {{4}}, publisher = {{MDPI AG}}, title = {{{Definition of High-Risk Motion Patterns for Female ACL Injury Based on Football-Specific Field Data: A Wearable Sensors Plus Data Mining Approach}}}, doi = {{10.3390/s23042176}}, volume = {{23}}, year = {{2023}}, } @article{45859, abstract = {{Sport-related concussions (SRC) are characterized by impaired autonomic control. Heart rate variability (HRV) offers easily obtainable diagnostic approaches to SRC-associated dysautonomia, but studies investigating HRV during sleep, a crucial time for post-traumatic cerebral regeneration, are relatively sparse. The aim of this study was to assess nocturnal HRV in athletes during their return to sports (RTS) after SRC in their home environment using wireless wrist sensors (E4, Empatica, Milan, Italy) and to explore possible relations with clinical concussion-associated sleep symptoms. Eighteen SRC athletes wore a wrist sensor obtaining photoplethysmographic data at night during RTS as well as one night after full clinical recovery post RTS (>3 weeks). Nocturnal heart rate and parasympathetic activity of HRV (RMSSD) were calculated and compared using the Mann–Whitney U Test to values of eighteen; matched by sex, age, sport, and expertise, control athletes underwent the identical protocol. During RTS, nocturnal RMSSD of SRC athletes (Mdn = 77.74 ms) showed a trend compared to controls (Mdn = 95.68 ms, p = 0.021, r = −0.382, p adjusted using false discovery rate = 0.126) and positively correlated to “drowsiness” (r = 0.523, p = 0.023, p adjusted = 0.046). Post RTS, no differences in RMSSD between groups were detected. The presented findings in nocturnal cardiac parasympathetic activity during nights of RTS in SRC athletes might be a result of concussion, although its relation to recovery still needs to be elucidated. Utilization of wireless sensors and wearable technologies in home-based settings offer a possibility to obtain helpful objective data in the management of SRC.}}, author = {{Delling, Anne Carina and Jakobsmeyer, Rasmus and Coenen, Jessica and Christiansen, Nele and Reinsberger, Claus}}, issn = {{1424-8220}}, journal = {{Sensors}}, keywords = {{Electrical and Electronic Engineering, Biochemistry, Instrumentation, Atomic and Molecular Physics, and Optics, Analytical Chemistry}}, number = {{9}}, publisher = {{MDPI AG}}, title = {{{Home-Based Measurements of Nocturnal Cardiac Parasympathetic Activity in Athletes during Return to Sport after Sport-Related Concussion}}}, doi = {{10.3390/s23094190}}, volume = {{23}}, year = {{2023}}, } @article{48053, author = {{Hetkämper, Tim and Claes, Leander and Henning, Bernd}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, keywords = {{Electrical and Electronic Engineering, Instrumentation}}, number = {{s1}}, pages = {{49--54}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Vorzeichenrichtige tomographische Rekonstruktion von Ultraschallfeldern mit Hilfe der Schlierentechnik}}}, doi = {{10.1515/teme-2023-0069}}, volume = {{90}}, year = {{2023}}, } @article{34223, abstract = {{In this study, quasi-unidirectional continuous fiber reinforced thermoplastics (CFRTs) are joined with metal sheets via cold formed cylindrical, elliptical and polygonal pin structures which are directly pressed into the CFRT component after local infrared heating. In comparison to already available studies, the unique novelty is the use of non-rotational symmetric pin structures for the CFRT/metal hybrid joining. Thus, a variation in the fiber orientation in the CFRT component as well as a variation in the non-rotational symmetric pins’ orientation in relation to the sample orientation is conducted. The created samples are consequently mechanically tested via single lap shear experiments in a quasi-static state. Finally, the failure behavior of the single lap shear samples is investigated with the help of microscopic images and detailed photographs. In the single lap shear tests, it could be shown that non-rotational symmetric pin structures lead to an increase in maximum testing forces of up to 74% when compared to cylindrical pins. However, when normalized to the pin foot print related joint strength, only one polygonal pin variation showed increased joint strength in comparison to cylindrical pin structures. The investigation of the failure behavior showed two distinct failure modes. The first failure mode was failure of the CFRT component due to an exceedance of the maximum bearing strength of the pin-hole leading to significant damage in the CFRT component. The second failure mode was pin-deflection due to the applied testing load and a subsequent pin extraction from the CFRT component resulting in significantly less visible damage in the CFRT component. Generally, CFRT failure is more likely with a fiber orientation of 0° in relation to the load direction while pin extraction typically occurs with a fiber orientation of 90°. It is assumed that for future investigations, pin structures with an undercutting shape that creates an interlocking joint could counteract the tendency for pin-extraction and consequently lead to increased maximum joint strengths.}}, author = {{Popp, Julian and Römisch, David and Merklein, Marion and Drummer, Dietmar}}, issn = {{2076-3417}}, journal = {{Applied Sciences}}, keywords = {{Fluid Flow and Transfer Processes, Computer Science Applications, Process Chemistry and Technology, General Engineering, Instrumentation, General Materials Science}}, number = {{10}}, publisher = {{MDPI AG}}, title = {{{Joining of CFRT/Steel Hybrid Parts via Direct Pressing of Cold Formed Non-Rotational Symmetric Pin Structures}}}, doi = {{10.3390/app12104962}}, volume = {{12}}, year = {{2022}}, } @article{34221, abstract = {{Unter dem Begriff der Auflösung wird für gewöhnlich das kleinste messbare Merkmal eines Messsystems verstanden. In der dimensionellen Computertomografie hingegen haben sich in den vergangenen Jahren mehrere Auflösungskonzepte etabliert, die aufgrund der fehlenden Normung zueinander im Kontrast stehen. In diesem Beitrag werden die drei häufigsten Konzepte, die Voxelgröße, die Ortsauflösung und die metrologische Strukturauflösung in Kürze vorgestellt. Anschließend wird eine Abgrenzung zwischen den Konzepten getroffen und ein Integration der bestehenden Konzepte in ein gemeinsames Amplituden-Wellenlängen Diagramm diskutiert.}}, author = {{Binder, Felix and Hausotte, Tino}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, keywords = {{Electrical and Electronic Engineering, Instrumentation}}, number = {{s1}}, pages = {{20--24}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Über die Abgrenzung von Auflösungskonzepten in der industriellen Computertomografie}}}, doi = {{10.1515/teme-2022-0065}}, volume = {{89}}, year = {{2022}}, } @article{34220, abstract = {{Die Erkennbarkeit von Rissen und geometrischen Qualitätskennwerten von Fügeverbindungen mittels Computertomografie ist von der Interfacestrukturauflösung abhängig, welche mittels geeigneter Prüfkörper untersucht wird. Die Reduktion von Abbildungsartefakten im Bereich von Bauteilzwischenräumen und -oberflächen verbessert deren dimensionelle Erfassbarkeit.}}, author = {{Busch, Matthias and Butzhammer, Lorenz and Hausotte, Tino}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, keywords = {{Electrical and Electronic Engineering, Instrumentation}}, number = {{s1}}, pages = {{83--88}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Herausforderungen bei computertomografischen Untersuchungen von Fügeverbindungen}}}, doi = {{10.1515/teme-2022-0061}}, volume = {{89}}, year = {{2022}}, } @article{34264, abstract = {{In industrial x-ray computed tomography (CT), the application of more complex scan paths in comparison to the typical circular trajectory (${360}^{\circ}$ rotation of the measurement object) can extend the potential of CT. One way to enable such 3D scan trajectories is to use a 6-degrees-of-freedom (DOF) object manipulator system. In our case, a hexapod is mounted on top of the rotary table of a commercial CT scanner. This allows for adaptive tilting of the measurement object during the scan. For high accuracy, the geometry calibration of such setups is typically done using the x-ray projections of a calibrated multi-sphere object. Contrary to this, here, we demonstrate a procedure that is based on only a single sphere and can therefore experimentally be implemented with low effort. Using the intrinsic geometry parameters of the CT device as prior information, the hexapod coordinate system with respect to the CT machine coordinate system is determined by means of a one-step optimization approach. The resulting parameters are used to calculate projection matrices that enable the volume reconstruction for 3D scan trajectories. The method is validated using simulated x-ray images and experimental investigations including dimensional measurements. For the used setup, geometric measurement results for 3D scan trajectories that are calibrated with the presented method show in sum increased errors compared to the circular scans. A limited pose accuracy of the manipulator system is discussed as a potential cause. The results nevertheless indicate that the presented method is generally feasible for dimensional CT measurements provided that the pose accuracy is sufficient. The calibration procedure can therefore be a low-cost and easier to implement alternative compared to trajectory calibration methods based on multi-sphere objects, but with a tendency towards lower measurement accuracy. The methodology can in principle be transferred to different setups with 6-DOF manipulator systems, e.g. C-arm CT devices with a robot arm.}}, author = {{Butzhammer, Lorenz and Müller, Andreas Michael and Hausotte, Tino}}, issn = {{0957-0233}}, journal = {{Measurement Science and Technology}}, keywords = {{Applied Mathematics, Instrumentation, Engineering (miscellaneous)}}, number = {{1}}, publisher = {{IOP Publishing}}, title = {{{Calibration of 3D scan trajectories for an industrial computed tomography setup with 6-DOF object manipulator system using a single sphere}}}, doi = {{10.1088/1361-6501/ac9856}}, volume = {{34}}, year = {{2022}}, } @article{34224, abstract = {{Crack growth in structures depends on the cyclic loads applied on it, such as mechanical, thermal and contact, as well as residual stresses, etc. To provide an accurate simulation of crack growth in structures, it is of high importance to integrate all kinds of loading situations in the simulations. Adapcrack3D is a simulation program that can accurately predict the propagation of cracks in real structures. However, until now, this three-dimensional program has only considered mechanical loads and static thermal loads. Therefore, the features of Adapcrack3D have been extended by including contact loading in crack growth simulations. The numerical simulation of crack propagation with Adapcrack3D is generally carried out using FE models of structures provided by the user. For simulating models with contact loading situations, Adapcrack3D has been updated to work with FE models containing multiple parts and necessary features such as coupling and surface interactions. Because Adapcrack3D uses the submodel technique for fracture mechanical evaluations, the architecture of the submodel is also modified to simulate models with contact definitions between the crack surfaces. This paper discusses the newly implemented attribute of the program with the help of illustrative examples. The results confirm that the contact simulation in Adapcrack3D is a major step in improving the functionality of the program.}}, author = {{Joy, Tintu David and Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}}, issn = {{2076-3417}}, journal = {{Applied Sciences}}, keywords = {{Fluid Flow and Transfer Processes, Computer Science Applications, Process Chemistry and Technology, General Engineering, Instrumentation, General Materials Science}}, number = {{15}}, publisher = {{MDPI AG}}, title = {{{Further Development of 3D Crack Growth Simulation Program to Include Contact Loading Situations}}}, doi = {{10.3390/app12157557}}, volume = {{12}}, year = {{2022}}, } @article{30213, abstract = {{Requirement changes and cascading effects of change propagation are major sources of inefficiencies in product development and increase the risk of project failure. Proactive change management of requirement changes yields the potential to handle such changes efficiently. A systematic approach is required for proactive change management to assess and reduce the risk of a requirement change with appropriate effort in industrial application. Within the paper at hand, a novel method for Proactive Management of Requirement Changes (ProMaRC) is presented. It is developed in close collaboration with industry experts and evaluated based on workshops, pilot users’ feedback, three industrial case studies from the automotive industry and five development projects from research. To limit the application effort, an automated approach for dependency analysis based on the machine learning technique BERT and semi-automated assessment of change likelihood and impact using a modified PageRank algorithm is developed. Applying the method, the risks of requirement changes are assessed systematically and reduced by means of proactive change measures. Evaluation shows high performance of dependency analysis and confirms the applicability and usefulness of the method. This contribution opens up the research space of proactive risk management for requirement changes which is currently almost unexploited. It enables more efficient product development.}}, author = {{Gräßler, Iris and Oleff, Christian and Preuß, Daniel}}, issn = {{2076-3417}}, journal = {{Applied Sciences}}, keywords = {{Fluid Flow and Transfer Processes, Computer Science Applications, Process Chemistry and Technology, General Engineering, Instrumentation, General Materials Science}}, number = {{4}}, publisher = {{MDPI AG}}, title = {{{Proactive Management of Requirement Changes in the Development of Complex Technical Systems}}}, doi = {{10.3390/app12041874}}, volume = {{12}}, year = {{2022}}, } @article{30863, abstract = {{Abstract In this paper a measurement procedure to identify viscoelastic material parameters of plate-like samples using broadband ultrasonic waves is presented. Ultrasonic Lamb waves are excited via the thermoelastic effect using laser radiation and detected by a piezoelectric transducer. The resulting measurement data is transformed to yield information about multiple propagating Lamb waves as well as their attenuation. These results are compared to simulation results in an inverse procedure to identify the parameters of an elastic and a viscoelastic material model.}}, author = {{Johannesmann, Sarah and Claes, Leander and Feldmann, Nadine and Zeipert, Henning and Henning, Bernd}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, keywords = {{Electrical and Electronic Engineering, Instrumentation}}, number = {{7 - 8}}, pages = {{493 -- 506}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Lamb wave based approach to the determination of acoustic material parameters}}}, doi = {{10.1515/teme-2021-0134}}, volume = {{89}}, year = {{2022}}, } @article{34054, abstract = {{AbstractColloidal nanosphere monolayers—used as a lithography mask for site-controlled material deposition or removal—offer the possibility of cost-effective patterning of large surface areas. In the present study, an automated analysis of scanning electron microscopy (SEM) images is described, which enables the recognition of the individual nanospheres in densely packed monolayers in order to perform a statistical quantification of the sphere size, mask opening size, and sphere-sphere separation distributions. Search algorithms based on Fourier transformation, cross-correlation, multiple-angle intensity profiling, and sphere edge point detection techniques allow for a sphere detection efficiency of at least 99.8%, even in the case of considerable sphere size variations. While the sphere positions and diameters are determined by fitting circles to the spheres edge points, the openings between sphere triples are detected by intensity thresholding. For the analyzed polystyrene sphere monolayers with sphere sizes between 220 and 600 nm and a diameter spread of around 3% coefficients of variation of 6.8–8.1% for the opening size are found. By correlating the mentioned size distributions, it is shown that, in this case, the dominant contribution to the opening size variation stems from nanometer-scale positional variations of the spheres.}}, author = {{Riedl, Thomas and Lindner, Jörg}}, issn = {{1431-9276}}, journal = {{Microscopy and Microanalysis}}, keywords = {{Instrumentation}}, number = {{1}}, pages = {{185--195}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{Automated SEM Image Analysis of the Sphere Diameter, Sphere-Sphere Separation, and Opening Size Distributions of Nanosphere Lithography Masks}}}, doi = {{10.1017/s1431927621013866}}, volume = {{28}}, year = {{2021}}, } @article{29813, author = {{Cieslar, Miroslav and Králík, Rostislav and Bajtošová, Lucia and Křivská, Barbora and Hájek, Michal and Belejová, Sára and Grydin, Olexandr and Stolbchenko, Mykhailo and Schaper, Mirko}}, issn = {{1431-9276}}, journal = {{Microscopy and Microanalysis}}, keywords = {{Instrumentation}}, number = {{S2}}, pages = {{79--80}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{High Temperature Annealing of Twin-Roll Cast Al-Li-Based Alloy Studied by In-situ SEM and STEM}}}, doi = {{10.1017/s1431927621013398}}, volume = {{27}}, year = {{2021}}, } @article{29814, author = {{Křivská, Barbora and Šlapáková, Michaela and Minárik, Peter and Fekete, Klaudia and Králík, Rostislav and Stolbchenko, Mykhailo and Schaper, Mirko and Grydin, Olexandr}}, issn = {{1431-9276}}, journal = {{Microscopy and Microanalysis}}, keywords = {{Instrumentation}}, number = {{S2}}, pages = {{91--92}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{Intermetallic Phase Growth in Al-steel Clad Strip during In-situ Heating in TEM}}}, doi = {{10.1017/s1431927621013453}}, volume = {{27}}, year = {{2021}}, } @article{35723, abstract = {{The development of renewable energies and smart mobility has profoundly impacted the future of the distribution grid. An increasing bidirectional energy flow stresses the assets of the distribution grid, especially medium voltage switchgear. This calls for improved maintenance strategies to prevent critical failures. Predictive maintenance, a maintenance strategy relying on current condition data of assets, serves as a guideline. Novel sensors covering thermal, mechanical, and partial discharge aspects of switchgear, enable continuous condition monitoring of some of the most critical assets of the distribution grid. Combined with machine learning algorithms, the demands put on the distribution grid by the energy and mobility revolutions can be handled. In this paper, we review the current state-of-the-art of all aspects of condition monitoring for medium voltage switchgear. Furthermore, we present an approach to develop a predictive maintenance system based on novel sensors and machine learning. We show how the existing medium voltage grid infrastructure can adapt these new needs on an economic scale.}}, author = {{Hoffmann, Martin W. and Wildermuth, Stephan and Gitzel, Ralf and Boyaci, Aydin and Gebhardt, Jörg and Kaul, Holger and Amihai, Ido and Forg, Bodo and Suriyah, Michael and Leibfried, Thomas and Stich, Volker and Hicking, Jan and Bremer, Martin and Kaminski, Lars and Beverungen, Daniel and zur Heiden, Philipp and Tornede, Tanja}}, issn = {{1424-8220}}, journal = {{Sensors}}, keywords = {{Electrical and Electronic Engineering, Biochemistry, Instrumentation, Atomic and Molecular Physics, and Optics, Analytical Chemistry}}, number = {{7}}, publisher = {{MDPI AG}}, title = {{{Integration of Novel Sensors and Machine Learning for Predictive Maintenance in Medium Voltage Switchgear to Enable the Energy and Mobility Revolutions}}}, doi = {{10.3390/s20072099}}, volume = {{20}}, year = {{2020}}, } @article{34088, author = {{Bürger, Julius and Riedl, Thomas and Lindner, Jörg}}, issn = {{0304-3991}}, journal = {{Ultramicroscopy}}, keywords = {{Instrumentation, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}}, publisher = {{Elsevier BV}}, title = {{{Influence of lens aberrations, specimen thickness and tilt on differential phase contrast STEM images}}}, doi = {{10.1016/j.ultramic.2020.113118}}, volume = {{219}}, year = {{2020}}, } @article{41024, author = {{Gujt, Jure and Zimmer, Peter and Zysk, Frederik and Süß, Vicky and Felser, Claudia and Bauer, Matthias and Kühne, Thomas}}, issn = {{2329-7778}}, journal = {{Structural Dynamics}}, keywords = {{Spectroscopy, Condensed Matter Physics, Instrumentation, Radiation}}, number = {{3}}, publisher = {{AIP Publishing}}, title = {{{Water structure near the surface of Weyl semimetals as catalysts in photocatalytic proton reduction}}}, doi = {{10.1063/4.0000008}}, volume = {{7}}, year = {{2020}}, } @article{37935, author = {{Meyer-Scott, Evan and Silberhorn, Christine and Migdall, Alan}}, issn = {{0034-6748}}, journal = {{Review of Scientific Instruments}}, keywords = {{Instrumentation}}, number = {{4}}, publisher = {{AIP Publishing}}, title = {{{Single-photon sources: Approaching the ideal through multiplexing}}}, doi = {{10.1063/5.0003320}}, volume = {{91}}, year = {{2020}}, } @article{32489, abstract = {{Abstract The stagnation point heat fluxes of methane/air flames impinging normal on a cylindrical surface were determined experimentally. Light induced phosphorescence from thermographic phosphors was used to investigate surface temperatures at the stagnation point from a nearly 1D laminar premixed flame burning against a water-cooled ceramic tube. The ceramic tube was coated with 1.1% chromium-doped alumina (ruby) at the impingement area and excited with a green light-emitting diode (LED) to measure the surface temperature. The flame temperature profiles were also measured with a thermocouple of type R (Pt/Pt  +  13% Rh). Effects on variations in cold gas velocity (0.1 m s−1–0.5 m s−1) relative to the flame speed, equivalence ratio (Ф  =  0.85–1.2), burner to impingement surface spacing (H/d  =  0.5–2) and surface curvature are reported. The stagnation point heat fluxes are strongly influenced by the flame stabilization mechanism, which changes from burner to wall stabilization, which also is seen from the measured flame temperature profiles. Increasing the cold gas velocity of the reactants leads to higher stagnation point heat fluxes. In addition, decreasing the distance between the burner and impingement surface increases the heat flux, with higher heat fluxes recorded for a tube compared to a flat plate.}}, author = {{Oketch, Peter Obara and Gonchikzhapov, Munko and Bergmann, Ulf and Atakan, Burak}}, issn = {{0957-0233}}, journal = {{Measurement Science and Technology}}, keywords = {{Applied Mathematics, Instrumentation, Engineering (miscellaneous)}}, number = {{9}}, publisher = {{IOP Publishing}}, title = {{{Thermographic phosphor heat flux measurements of laminar methane/air flame impinging on a cylindrical surface}}}, doi = {{10.1088/1361-6501/ab217e}}, volume = {{30}}, year = {{2019}}, }