TY  - JOUR
A1  - Müller, Martin
A1  - Hirschfeld, Julian
A1  - Lambertz, Rita
A1  - Schulze Lohoff, Andreas
A1  - Lustfeld, Hans
A1  - Pfeifer, Heinz
A1  - Reißel, Martin
T1  - Validation of a novel method for detecting and stabilizing malfunctioning areas in fuel cell stacks
JF  - Journal of power sources
N2  - In this paper a setup for detecting malfunctioning areas of MEAs in fuel cell stacks is described. Malfunctioning areas generate electric cross currents inside bipolar plates. To exploit this we suggest bipolar plates consisting not of two but of three layers. The third one is a highly conducting layer and segmented such that the cross currents move along the segments to the surface of the stack where they can be measured by an inductive sensor. With this information a realistic model can be used to detect the malfunctioning area. Furthermore the third layer will prevent any current inhomogeneity of a malfunctioning cell to spread to neighbouring cells in the stack. In this work the results of measurements in a realistic cell setup will be compared with the results obtained in simulation studies with the same configuration. The basis for the comparison is the reliable characterisation of the electrical properties of the cell components and the implication of these results into the simulation model. The experimental studies will also show the limits in the maximum number of segments, which can be used for a reliable detection of cross currents.
Y1  - 2014
U6  - https://doi.org/10.1016/j.jpowsour.2014.08.045
SN  - 1873-2755 (E-Journal); 0378-7753 (Print)
VL  - 272
SP  - 225
EP  - 232
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Müller, Tim M.
A1  - Schmitt, Andreas
A1  - Leise, Philipp
A1  - Meck, Tobias
A1  - Altherr, Lena
A1  - Pelz, Peter F.
A1  - Pfetsch, Marc E.
T1  - Validation of an optimized resilient water supply system
T2  - Uncertainty in Mechanical Engineering
N2  - Component failures within water supply systems can lead to significant performance losses. One way to address these losses is the explicit anticipation of failures within the design process. We consider a water supply system for high-rise buildings, where pump failures are the most likely failure scenarios. We explicitly consider these failures within an early design stage which leads to a more resilient system, i.e., a system which is able to operate under a predefined number of arbitrary pump failures. We use a mathematical optimization approach to compute such a resilient design. This is based on a multi-stage model for topology optimization, which can be described by a system of nonlinear inequalities and integrality constraints. Such a model has to be both computationally tractable and to represent the real-world system accurately. We therefore validate the algorithmic solutions using experiments on a scaled test rig for high-rise buildings. The test rig allows for an arbitrary connection of pumps to reproduce scaled versions of booster station designs for high-rise buildings. We experimentally verify the applicability of the presented optimization model and that the proposed resilience properties are also fulfilled in real systems.
KW  - Optimization
KW  - Mixed-integer nonlinear programming
KW  - Water distribution system
KW  - Resilience
KW  - Validation
Y1  - 2021
SN  - 978-3-030-77255-0
SN  - 978-3-030-77256-7
U6  - https://doi.org/10.1007/978-3-030-77256-7_7
N1  - Proceedings of the 4th International Conference on Uncertainty in Mechanical Engineering (ICUME 2021), June 7–8, 2021
SP  - 70
EP  - 80
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
A1  - Heinrichs, U.
A1  - Streun, M.
A1  - Pietrzyk, U.
T1  - Validation of GEANT3 simulation studies with a dual-head PMT ClearPET™ prototype
JF  - 2003 IEEE Nuclear Science Symposium Conference Record, Vol. 5
N2  - The ClearPET™ project is proposed by working groups of the Crystal Clear Collaboration (CCC) to develop a 2nd generation high performance small animal positron emission tomograph (PET). High sensitivity and high spatial resolution is foreseen for the ClearPET™ camera by using a phoswich arrangement combining mixed lutetium yttrium aluminum perovskite (LuYAP:Ce) and lutetium oxyorthosilicate (LSO) scintillating crystals. Design optimizations for the first photomultiplier tube (PMT) based ClearPET camera are done with a Monte-Carlo simulation package implemented on GEANT3 (CERN, Geneva, Switzerland). A dual-head prototype has been built to test the frontend electronics and was used to validate the implementation of the GEANT3 simulation tool. Multiple simulations were performed following the experimental protocols to measure the intrinsic resolution and the sensitivity profile in axial and radial direction. Including a mean energy resolution of about 27.0% the simulated intrinsic resolution is about (1.41±0.11)mm compared to the measured of (1.48±0.06)mm. The simulated sensitivity profiles show a mean square deviation of 12.6% in axial direction and 3.6% in radial direction. Satisfactorily these results are representative for all designs and confirm the scanner geometry.
Y1  - 2004
SN  - 1082-3654
SP  - 3053
EP  - 3056
ER  - 
TY  - JOUR
A1  - German, Laura
A1  - Mikucki, Jill A.
A1  - Welch, Susan A.
A1  - Welch, Kathleen A.
A1  - Lutton, Anthony
A1  - Dachwald, Bernd
A1  - Kowalski, Julia
A1  - Heinen, Dirk
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Espe, Clemens
A1  - Lyons, W. Berry
T1  - Validation of sampling antarctic subglacial hypersaline waters with an electrothermal ice melting probe (IceMole) for environmental analytical geochemistry
JF  - International Journal of Environmental Analytical Chemistry
N2  - Geochemical characterisation of hypersaline waters is difficult as high concentrations of salts hinder the analysis of constituents at low concentrations, such as trace metals, and the collection of samples for trace metal analysis in natural waters can be easily contaminated. This is particularly the case if samples are collected by non-conventional techniques such as those required for aquatic subglacial environments. In this paper we present the first analysis of a subglacial brine from Taylor Valley, (~ 78°S), Antarctica for the trace metals: Ba, Co, Mo, Rb, Sr, V, and U. Samples were collected englacially using an electrothermal melting probe called the IceMole. This probe uses differential heating of a copper head as well as the probe’s sidewalls and an ice screw at the melting head to move through glacier ice. Detailed blanks, meltwater, and subglacial brine samples were collected to evaluate the impact of the IceMole and the borehole pump, the melting and collection process, filtration, and storage on the geochemistry of the samples collected by this device. Comparisons between melt water profiles through the glacier ice and blank analysis, with published studies on ice geochemistry, suggest the potential for minor contributions of some species Rb, As, Co, Mn, Ni, NH4+, and NO2−+NO3− from the IceMole. The ability to conduct detailed chemical analyses of subglacial fluids collected with melting probes is critical for the future exploration of the hundreds of deep subglacial lakes in Antarctica.
Y1  - 2021
U6  - https://doi.org/10.1080/03067319.2019.1704750
SN  - 0306-7319
VL  - 101
IS  - 15
SP  - 2654
EP  - 2667
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Jablonowski, Nicolai David
A1  - Kollmann, Tobias
A1  - Nabel, Moritz
A1  - Damm, Tatjana
A1  - Klose, Holger
A1  - Müller, Michael
A1  - Bläsing, Marc
A1  - Seebold, Sören
A1  - Krafft, Simone
A1  - Kuperjans, Isabel
A1  - Dahmen, Markus
A1  - Schurr, Ulrich
T1  - Valorization of Sida (Sida hermaphrodita) biomass for multiple energy purposes
JF  - GCB [Global Change Biology] Bioenergy
N2  - The performance and biomass yield of the perennial energy plant Sida hermaphrodita (hereafter referred to as Sida) as a feedstock for biogas and solid fuel was evaluated throughout one entire growing period at agricultural field conditions. A Sida plant development code was established to allow comparison of the plant growth stages and biomass composition. Four scenarios were evaluated to determine the use of Sida biomass with regard to plant development and harvest time: (i) one harvest for solid fuel only; (ii) one harvest for biogas production only; (iii) one harvest for biogas production, followed by a harvest of the regrown biomass for solid fuel; and (iv) two consecutive harvests for biogas production. To determine Sida's value as a feedstock for combustion, we assessed the caloric value, the ash quality, and melting point with regard to DIN EN ISO norms. The results showed highest total dry biomass yields of max. 25 t ha⁻¹, whereas the highest dry matter of 70% to 80% was obtained at the end of the growing period. Scenario (i) clearly indicated the highest energy recovery, accounting for 439 288 MJ ha⁻¹; the energy recovery of the four scenarios from highest to lowest followed this order: (i) ≫ (iii) ≫ (iv) > (ii). Analysis of the Sida ashes showed a high melting point of >1500 °C, associated with a net calorific value of 16.5–17.2 MJ kg⁻¹. All prerequisites for DIN EN ISO norms were achieved, indicating Sida's advantage as a solid energy carrier without any post-treatment after harvesting. Cell wall analysis of the stems showed a constant lignin content after sampling week 16 (July), whereas cellulose had already reached a plateau in sampling week 4 (April). The results highlight Sida as a promising woody, perennial plant, providing biomass for flexible and multipurpose energy applications.
Y1  - 2016
U6  - https://doi.org/10.1111/gcbb.12346
SN  - 1757-1707 (online)
SN  - 1757-1693 (print)
N1  - Special Issue: Perennial biomass crops for a resource constrained world
VL  - 9
IS  - 1
SP  - 202
EP  - 214
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Yazdanbakhsh, Pedram
A1  - Solbach, Klaus
A1  - Bitz, Andreas
T1  - Variable power combiner for RF mode shimming in 7-T MR imaging
JF  - IEEE Transaction on Biomedical Engineering
N2  - This contribution discusses the utilization of RF power in an MRI system with RF mode shimming which enables the superposition of circularly polarized modes of a transmit RF coil array driven by a Butler matrix. Since the required power for the individual modes can vary widely, mode-shimming can result in a significant underutilization of the total available RF power. A variable power combiner (VPC) is proposed to improve the power utilization: it can be realized as a reconfiguration of the MRI transmit system by the inclusion of one additional matrix network which receives the power from all transmit amplifiers at its input ports and provides any desired (combined) power distribution at its output ports by controlling the phase and amplitude of the amplifiers’ input signals. The power distribution at the output ports of the VPC is then fed into the “mode” ports of the coil array Butler matrix in order to superimpose the spatial modes at the highest achievable power utilization. The VPC configuration is compared to the standard configuration of the transmit chain of our MRI system with 8 transmit channels and 16 coils. In realistic scenarios, improved power utilization was achieved from 17% to 60% and from 14% to 55% for an elliptical phantom and a region of interest in the abdomen, respectively, and an increase of the power utilization of 1 dB for a region of interest in the upper leg. In general, it is found that the VPC allows significant improvement in power utilization when the shimming solution demands only a few modes to be energized, while the technique can yield loss in power utilization in cases with many modes required at high power level.
Y1  - 2012
U6  - https://doi.org/10.1109/TBME.2012.2205926
SN  - 1558-2531
VL  - 59
IS  - 9
SP  - 2549
EP  - 2557
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Conzen, Catharina
A1  - Albanna, Walid
A1  - Weiss, Miriam
A1  - Kürten, David
A1  - Vilser, Walthard
A1  - Kotliar, Konstantin
A1  - Zäske, Charlotte
A1  - Clusmann, Hans
A1  - Schubert, Gerrit Alexander
T1  - Vasoconstriction and Impairment of Neurovascular Coupling after Subarachnoid Hemorrhage: a Descriptive Analysis of Retinal Changes
JF  - Translational Stroke Research
N2  - Impaired cerebral autoregulation and neurovascular coupling (NVC) contribute to delayed cerebral ischemia after subarachnoid hemorrhage (SAH). Retinal vessel analysis (RVA) allows non-invasive assessment of vessel dimension and NVC hereby demonstrating a predictive value in the context of various neurovascular diseases. Using RVA as a translational approach, we aimed to assess the retinal vessels in patients with SAH. RVA was performed prospectively in 24 patients with acute SAH (group A: day 5–14), in 11 patients 3 months after ictus (group B: day 90 ± 35), and in 35 age-matched healthy controls (group C). Data was acquired using a Retinal Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and NVC using flicker-light excitation. Diameter of retinal vessels—central retinal arteriolar and venular equivalent—was significantly reduced in the acute phase (p < 0.001) with gradual improvement in group B (p < 0.05). Arterial NVC of group A was significantly impaired with diminished dilatation (p < 0.001) and reduced area under the curve (p < 0.01) when compared to group C. Group B showed persistent prolonged latency of arterial dilation (p < 0.05). Venous NVC was significantly delayed after SAH compared to group C (A p < 0.001; B p < 0.05). To our knowledge, this is the first clinical study to document retinal vasoconstriction and impairment of NVC in patients with SAH. Using non-invasive RVA as a translational approach, characteristic patterns of compromise were detected for the arterial and venous compartment of the neurovascular unit in a time-dependent fashion. Recruitment will continue to facilitate a correlation analysis with clinical course and outcome.
Y1  - 2018
U6  - https://doi.org/10.1007/s12975-017-0585-8
SN  - 1868-601X
IS  - 9
SP  - 284
EP  - 293
PB  - Springer Nature
CY  - Cham
ER  - 
TY  - CHAP
A1  - Blum, Yannik
A1  - Albanna, Walid
A1  - Benninghaus, Anne
A1  - Kotliar, Konstantin
ED  - Staat, Manfred
ED  - Erni, Daniel
T1  - Vasomotion in retinal vessels of patients presenting post hemorrhagic hydrocephalus following subarachnoid hemorrhage
T2  - 3rd YRA MedTech Symposium 2019 : May 24 / 2019 / FH Aachen
N2  - Clearance of blood components and fluid drainage play a crucial role in subarachnoid hemorrhage (SAH) and post hemorrhagic hydrocephalus (PHH). With the involvement of interstitial fluid (ISF) and cerebrospinal fluid (CSF), two pathways for the clearance of fluid and solutes in the brain are proposed. Starting at the level of capillaries, flow of ISF follows along the basement membranes in the walls of cerebral arteries out of the parenchyma to drain into the lymphatics and CSF [1]–[3]. Conversely, it is shown that CSF enters the parenchyma between glial and pial basement membranes of penetrating arteries [4]–[6]. Nevertheless, the involved structures and the contribution of either flow pathway to fluid balance between the subarachnoid space and interstitial space remains controversial. Low frequency oscillations in vascular tone are referred to as vasomotion and corresponding vasomotion waves are modeled as the driving force for flow of ISF out of the parenchyma [7]. Retinal vessel analysis (RVA) allows non-invasive measurement of retinal vessel vasomotion with respect to diameter changes [8]. Thus, the aim of the study is to investigate vasomotion in RVA signals of SAH and PHH patients.
Y1  - 2019
SN  - 978-3-940402-22-6
U6  - https://doi.org/10.17185/duepublico/48750
SP  - 38
EP  - 39
PB  - Universität Duisburg-Essen
CY  - Duisburg
ER  - 
TY  - JOUR
A1  - Giresini, Linda
A1  - Sassu, Mauro
A1  - Butenweg, Christoph
A1  - Alecci, Valerio
A1  - De Stefano, Mario
T1  - Vault macro-element with equivalent trusses in global seismic analyses
JF  - Earthquakes and Structures
N2  - This paper proposes a quick and simplified method to describe masonry vaults in global seismic analyses of buildings. An equivalent macro-element constituted by a set of six trusses, two for each transverse, longitudinal and diagonal direction, is introduced. The equivalent trusses, whose stiffness is calculated by fully modeled vaults of different geometry, mechanical properties and boundary conditions, simulate the vault in both global analysis and local analysis, such as kinematic or rocking approaches. A parametric study was carried out to investigate the influence of geometrical characteristics and mechanical features on the equivalent stiffness values. The method was numerically validated by performing modal and transient analysis on a three naves-church in the elastic range. Vibration modes and displacement time-histories were compared showing satisfying agreement between the complete and the simplified models. This procedure is particularly useful in engineering practice because it allows to assess, in a simplified way, the effectiveness of strengthening interventions for reducing horizontal relative displacements between vault supports.
KW  - vault
KW  - macro-element
KW  - equivalent stiffness
KW  - truss
KW  - churches
Y1  - 2017
U6  - https://doi.org/10.12989/eas.2017.12.4.409
SN  - 2092-7614 (Print)
SN  - 2092-7622 (Online)
VL  - 12
IS  - 4
SP  - 409
EP  - 423
PB  - Techno-Press
CY  - Taejŏn
ER  - 
TY  - JOUR
A1  - Pieper, Martin
T1  - Vector hyperinterpolation on the sphere
JF  - Journal of approximation theory. 156 (2009), H. 2
Y1  - 2009
SN  - 0021-9045
SP  - 173
EP  - 186
ER  - 
TY  - JOUR
A1  - Heuermann, Holger
A1  - Ibrahim, Irfan
A1  - Hillebrand, J.
T1  - Vector-Signal-Generator with Two ¿¿-PLL's / Ibrahim, I. ; Hillebrand, J. ; Heuermann, H.
JF  - European Conference on Wireless Technologies, 2007. ECWT 2007  ; 8 - 10 October 2007 Munich, Germany
Y1  - 2007
SN  - 978-2-87487-003-3
SP  - 1
EP  - 4
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel Bernhard
T1  - Vectrino profiler spatial filtering for shear flows based on the mean velocity gradient equation
JF  - Journal of Hydraulic Engineering
N2  - A new methodology is proposed to spatially filter acoustic Doppler velocimetry data from a Vectrino profiler based on the differential mean velocity equation. Lower and upper bounds are formulated in terms of physically based flow constraints. Practical implementation is discussed, and its application is tested against data gathered from an open-channel flow over a stepped macroroughness surface. The method has proven to detect outliers occurring all over the distance range sampled by the Vectrino profiler and has shown to remain applicable out of the region of validity of the velocity gradient equation. Finally, a statistical analysis suggests that physically obtained bounds are asymptotically representative.
Y1  - 2018
U6  - https://doi.org/10.1061/(ASCE)HY.1943-7900.0001485
SN  - 0733-9429
N1  - Article number 04018037
VL  - 144
IS  - 7
PB  - ASCE
CY  - Reston, Va.
ER  - 
TY  - CHAP
A1  - Döring, Bernd
A1  - Ziller, Claudia
A1  - Hortmanns, M.
T1  - Ventilation of double facades by external dynamic wind pressure
T2  - 11th International Conference on Wind Engineering. 1
Y1  - 2003
SP  - 721
EP  - 730
PB  - The Wind Science and Engineering Research Center
CY  - Lubbock, Tex.
ER  - 
TY  - CHAP
A1  - Tewari, Udit
A1  - Neshvad, Surena
A1  - Goldbach, Daniel
A1  - Sachau, Jürgen
T1  - Verification and Implementation of Pseudo-Random-Binary-Sequences for Online Determination of Grid Impedance Spectrum
T2  - International Conference on Renewable Energies and Power Quality (ICREPQ´15), La Conuna, Spain, 25th to 27th March, 2015
Y1  - 2015
ER  - 
TY  - JOUR
A1  - Helsper, Christoph
A1  - Fißan, H. J.
A1  - Muggli, J.
A1  - Scheidweiler, A.
T1  - Verification of Ionization Chamber Theory
JF  - Fire Technology. 19 (1983), H. 1
Y1  - 1983
SN  - 1572-8099
SP  - 14
EP  - 21
ER  - 
TY  - JOUR
A1  - Heierli, Joachim
A1  - Purves, Ross S.
A1  - Felber, Andreas
A1  - Kowalski, Julia
T1  - Verification of nearest-neighbours interpretations in avalanche forecasting
JF  - Annals of Glaciology
N2  - This paper examines the positive and negative aspects of a range of interpretations of nearest-neighbours models. Measures-oriented and distributionoriented verification methods are applied to categorial, probabilistic and descriptive interpretations of nearest neighbours used operationally in avalanche forecasting in Scotland and Switzerland. The dependence of skill and accuracy measures on base rate is illustrated. The purpose of the forecast and the definition of events are important variables in determining the quality of the forecast. A discussion of the application of different interpretations in operational avalanche forecasting is presented.
KW  - avalanche
Y1  - 2004
SN  - 1727-5644
VL  - 38
IS  - 1
SP  - 84
EP  - 88
ER  - 
TY  - JOUR
A1  - Heuermann, Holger
T1  - Verringerung des Phasenrauschens von Oszillatoren durch Dual-Mode-Resonatoren
JF  - HF-Report. 20 (2006), H. 5-6
Y1  - 2006
SN  - 1431-827X
SP  - 43
EP  - 48
ER  - 
TY  - JOUR
A1  - Förster, Arnold
A1  - Malzer, S.
A1  - Heber, J.
A1  - Peter, M.
T1  - Vertical transport and relaxation mechanisms in d-doping superlattices. Malzer, S.; Heber, J.; Peter, M.; Eckl, S.; Elpelt, R.; Doehler, G. H.; Förster, A.; Lüth, H.
JF  - Physica E: Low-dimensional Systems and Nanostructures. 2 (1998), H. 1-4
Y1  - 1998
SN  - 1386-9477
SP  - 349
EP  - 352
ER  - 
TY  - JOUR
A1  - Vogt, C.
A1  - Mottaghy, Darius
A1  - Rath, V.
A1  - Marquart, G.
A1  - Dijkshoorn, L.
A1  - Wolf, A.
A1  - Clauser, C.
T1  - Vertical variation in heat flow on the Kola Peninsula: palaeoclimate or fluid flow?
JF  - Geophysical Journal International
N2  - Following earlier studies, we present forward and inverse simulations of heat and fluid transport of the upper crust using a local 3-D model of the Kola area. We provide best estimates for palaeotemperatures and permeabilities, their errors and their dependencies. Our results allow discriminating between the two mentioned processes to a certain extent, partly resolving the non-uniqueness of the problem. We find clear indications for a significant contribution of advective heat transport, which, in turn, imply only slightly lower ground surface temperatures during the last glacial maximum relative to the present value. These findings are consistent with the general background knowledge of (i) the fracture zones and the corresponding fluid movements in the bedrock and (ii) the glacial history of the Kola area.
Y1  - 2014
U6  - https://doi.org/10.1093/gji/ggu282
SN  - 1365-246X
VL  - 199
IS  - 2
SP  - 829
EP  - 843
PB  - Oxford University Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Hoskens, R. C. P.
A1  - Tolstikhin, V.I.
A1  - Förster, Arnold
A1  - Roer, T.G. van de
T1  - Vertically integrated transistor-laser structure, take 2
JF  - WOCSDICE  2000, 24th Workshop on Compound Semiconductor Devices and Integrated Circuits held in Europe : May 29 - June 02, 2000, Aegean Sea, Greece.
Y1  - 2000
SN  - 0970311109
N1  - WOCSDICE ; (24, 2000) Workshop on Compound Semiconductor Devices and Integrated Circuits held in Europe ; (24 : ; 2000.05.29-06.02)
PB  - Univ. of Michigan
CY  - Ann Arbor, Mich.
ER  - 
TY  - JOUR
A1  - Theysohn, Jens M.
A1  - Kraff, Oliver
A1  - Eilers, Kristina
A1  - Andrade, Dorian
A1  - Gerwig, Marcus
A1  - Timmann, Dagmar
A1  - Schmitt, Franz
A1  - Ladd, Mark E.
A1  - Ladd, Susanne C.
A1  - Bitz, Andreas
T1  - Vestibular effects of a 7 Tesla MRI examination compared to 1.5 T and 0 T in healthy volunteers
JF  - PLoS one
N2  - Ultra-high-field MRI (7 Tesla (T) and above) elicits more temporary side-effects compared to 1.5 T and 3 T, e.g. dizziness or “postural instability” even after exiting the scanner. The current study aims to assess quantitatively vestibular performance before and after exposure to different MRI scenarios at 7 T, 1.5 T and 0 T. Sway path and body axis rotation (Unterberger's stepping test) were quantitatively recorded in a total of 46 volunteers before, 2 minutes after, and 15 minutes after different exposure scenarios: 7 T head MRI (n = 27), 7 T no RF (n = 22), 7 T only B₀ (n = 20), 7 T in & out B₀ (n = 20), 1.5 T no RF (n = 20), 0 T (n = 15). All exposure scenarios lasted 30 minutes except for brief one minute exposure in 7 T in & out B₀. Both measures were documented utilizing a 3D ultrasound system. During sway path evaluation, the experiment was repeated with eyes both open and closed. Sway paths for all long-lasting 7 T scenarios (normal, no RF, only B₀) with eyes closed were significantly prolonged 2 minutes after exiting the scanner, normalizing after 15 minutes. Brief exposure to 7 T B₀ or 30 minutes exposure to 1.5 T or 0 T did not show significant changes. End positions after Unterberger's stepping test were significantly changed counter-clockwise after all 7 T scenarios, including the brief in & out B₀ exposure. Shorter exposure resulted in a smaller alteration angle. In contrast to sway path, reversal of changes in body axis rotation was incomplete after 15 minutes. 1.5 T caused no rotational changes. The results show that exposure to the 7 Tesla static magnetic field causes only a temporary dysfunction or “over-compensation” of the vestibular system not measurable at 1.5 or 0 Tesla. Radiofrequency fields, gradient switching, and orthostatic dysregulation do not seem to play a role.
Y1  - 2014
U6  - https://doi.org/10.1371/journal.pone.0092104
SN  - 1932-6203
VL  - 9
IS  - 3
PB  - PLOS
CY  - San Francisco
ER  - 
TY  - CHAP
A1  - Altay, Okyay
A1  - Butenweg, Christoph
A1  - Klinkel, Sven
T1  - Vibration control of slender structures by semi-active tuned liquid column dampers
T2  - Conference of the ASCE Engineering Mechanics Institute , Evanston, IL , USA , EMI 2013 , 2013-08-04 - 2013-08-07
Y1  - 2013
N1  - http://www.emi2013.northwestern.edu/openconf/modules/request.php?module=oc_program&action=view.php&a=&id=213&type=1
Seite kann nicht gefunden werden.
ER  - 
TY  - CHAP
A1  - Altay, Okyay
A1  - Butenweg, Christoph
A1  - Klinkel, Sven
T1  - Vibration mitigation of wind turbine towers by a new semiactive Tuned Liquid Column Damper
T2  - 6. Word Congress on Structural Control and Monitoring, 15 - 17 July, 2014 Barcelona,Spain
Y1  - 2014
ER  - 
TY  - CHAP
A1  - Altay, Okyay
A1  - Butenweg, Christoph
A1  - Klinkel, Sven
A1  - Taddei, Francesca
T1  - Vibration mitigation of wind turbine towers by tuned liquid column dampers
T2  - Proceedings of the 9th European Conference on Structural Dynamics, EURODYN 2014 Porto, Portugal, 30 June - 2 July 2014 / A. Cunha, E. Caetano, .... (eds.)
Y1  - 2014
SN  - 978-972-752-165-4
SP  - 1531
EP  - 1538
CY  - Porto
ER  - 
TY  - CHAP
A1  - Altay, Okyay
A1  - Taddei, Francesca
A1  - Butenweg, Christoph
A1  - Klinkel, Sven
T1  - Vibration mitigation of wind turbine towers with tuned mass dampers
T2  - Wind turbine control and monitoring. (Advances in industrial control)
N2  - Because of its minor environmental impact, electricity generation using wind power is getting remarkable. The further growth of the wind industry depends on technological solutions to the challenges in production and construction of the turbines. Wind turbine tower vibrations, which limit power generation efficiency and cause fatigue problems with high maintenance costs, count as one of the main structural difficulties in the wind energy sector. To mitigate tower vibrations auxiliary measures are necessary. The effectiveness of tuned mass damper is verified by means of a numeric study on a 5 MW onshore reference wind turbine. Hereby, also seismic-induced vibrations and soil–structure interaction are considered. Acquired results show that tuned mass damper can effectively reduce resonant tower vibrations and improve the fatigue life of wind turbines. This chapter is also concerned with tuned liquid column damper and a semiactive application of it. Due to its geometric versatility and low prime costs, tuned liquid column dampers are a good alternative to other damping measures, in particular for slender structures like wind turbines.
Y1  - 2014
SN  - 978-3-319-08412-1 (Print) ; 978-3-319-08413-8 (E-Book)
U6  - https://doi.org/10.1007/978-3-319-08413-8_12
SP  - 337
EP  - 373
PB  - Springer
CY  - Cham ; Heidelberg ; New York ; Dordrecht ; London
ER  - 
TY  - JOUR
A1  - Mathiak, Gerhard
A1  - Willnecker, Rainer
A1  - Plescher, Engelbert
T1  - Vibrational effects on diffusion experiments
JF  - Microgravity science and technology : international journal for microgravity research and applications
Y1  - 2005
SN  - 0938-0108
VL  - Vol. 15
IS  - No. 1
SP  - 295
EP  - 300
ER  - 
TY  - CHAP
A1  - Ahlbrink, N.
A1  - Alexopoulos, Spiros
A1  - Andersson, J.
A1  - Belhomme, B.
A1  - Teixeira Boura, Cristiano José
A1  - Gall, J.
A1  - Hirsch, T.
T1  - viCERP - the Virtual Institute of Central Receiver Power Plant
T2  - MATHMOD 2009 - 6th Vienna International Conference on Mathematical Modelling : February 11 - 13, 2009, Vienna, Austria. ARGESIM Report. No. 35
Y1  - 2009
SN  - 978-3-901608-35-3
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Golland, Alexander
A1  - Ohrtmann, Jan-Peter
T1  - Video surveillance: The supervisory authorities’ view andrecent case law
T2  - Turning Point in Data Protection Law
Y1  - 2020
SN  - 978-3-8487-6909-4
U6  - https://doi.org/10.5771/9783748921561-175
SP  - 175
EP  - 178
PB  - Nomos
CY  - Baden-Baden
ER  - 
TY  - CHAP
A1  - Galdi, Chiara
A1  - Hartung, Frank
A1  - Dugelay, Jean-Luc
T1  - Videos versus still images: Asymmetric sensor pattern noise comparison on mobile phones
T2  - Electronic Imaging
N2  - Nowadays, the most employed devices for recoding videos or capturing images are undoubtedly the smartphones. Our work investigates the application of source camera identification on mobile phones. We present a dataset entirely collected by mobile phones. The dataset contains both still images and videos collected by 67 different smartphones. Part of the images consists in photos of uniform backgrounds, especially collected for the computation of the RSPN. Identifying the source camera given a video is particularly challenging due to the strong video compression. The experiments reported in this paper, show the large variation in performance when testing an highly accurate technique on still images and videos.
KW  - Image Forensics
KW  - Mobile Phones
KW  - Image Database
Y1  - 2017
U6  - https://doi.org/10.2352/ISSN.2470-1173.2017.7.MWSF-331
SN  - 2470-1173
N1  - IS&T International Symposium on Electronic Imaging 2017
Media Watermarking, Security, and Forensics 2017
SP  - 100
EP  - 103
PB  - Society for Imaging Science and Technology
CY  - Springfield, Virginia
ER  - 
TY  - JOUR
A1  - Bhattarai, Aroj
A1  - Horbach, Andreas
A1  - Staat, Manfred
A1  - Kowalczyk, Wojciech
A1  - Tran, Thanh Ngoc
T1  - Virgin passive colon biomechanics and a literature review of active contraction constitutive models
JF  - Biomechanics
N2  - The objective of this paper is to present our findings on the biomechanical aspects of the virgin passive anisotropic hyperelasticity of the porcine colon based on equibiaxial tensile experiments. Firstly, the characterization of the intestine tissues is discussed for a nearly incompressible hyperelastic fiber-reinforced Holzapfel–Gasser–Ogden constitutive model in virgin passive loading conditions. The stability of the evaluated material parameters is checked for the polyconvexity of the adopted strain energy function using positive eigenvalue constraints of the Hessian matrix with MATLAB. The constitutive material description of the intestine with two collagen fibers in the submucosal and muscular layer each has been implemented in the FORTRAN platform of the commercial finite element software LS-DYNA, and two equibiaxial tensile simulations are presented to validate the results with the optical strain images obtained from the experiments. Furthermore, this paper also reviews the existing models of the active smooth muscle cells, but these models have not been computationally studied here. The review part shows that the constitutive models originally developed for the active contraction of skeletal muscle based on Hill’s three-element model, Murphy’s four-state cross-bridge chemical kinetic model and Huxley’s sliding-filament hypothesis, which are mainly used for arteries, are appropriate for numerical contraction numerical analysis of the large intestine.
KW  - virgin passive
KW  - strain energy function
KW  - smooth muscle contraction
KW  - viscoelasticity
KW  - damage
Y1  - 2022
U6  - https://doi.org/10.3390/biomechanics2020013
SN  - 2673-7078
VL  - 2
IS  - 2
SP  - 138
EP  - 157
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Ullrich, Sebastian
A1  - Grottke, Oliver
A1  - Rossaint, Rolf
A1  - Staat, Manfred
A1  - Deserno, Thomas M.
A1  - Kuhlen, Torsten
T1  - Virtual Needle Simulation with Haptics for Regional Anaesthesia
Y1  - 2010
N1  - IEEE Virtual Reality 2010, Workshop on Medical Virtual Environments, Waltham, MA, USA, March 21, 2010
SP  - 1
EP  - 3
ER  - 
TY  - JOUR
A1  - Bartella, Alexander K.
A1  - Kamal, Mohammad
A1  - Scholl, Ingrid
A1  - Schiffer, Stefan
A1  - Steegmann, Julius
A1  - Ketelsen, Dominik
A1  - Hölzle, Frank W.
A1  - Lethaus, Bernd
T1  - Virtual reality in preoperative imaging in maxillofacial surgery: implementation of “the next level”?
JF  - British Journal of Oral and Maxillofacial Surgery
Y1  - 2019
U6  - https://doi.org/10.1016/j.bjoms.2019.02.014
SN  - 0266-4356
VL  - 57
IS  - 7
SP  - 644
EP  - 648
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Reisgen, Uwe
A1  - Schleser, Markus
A1  - Mokrov, Oleg
A1  - Zabirov, Alexander
T1  - Virtual welding equipment for simulation of GMAW processes with integration of power source regulation
JF  - Frontiers of materials science
Y1  - 2011
SN  - 2095-0268 (E-Journal); 2095-025X (Print)
VL  - Vol. 5
IS  - Iss. 2
SP  - 79
EP  - 89
PB  - Springer
CY  - Berlin
ER  - 
TY  - BOOK
A1  - Boonzaaijer, Karel
A1  - Helmig, Ilka
A1  - Bergerhausen, Johannes
A1  - Beudaert, Matthieu
T1  - Vision - space for imagination
T2  - Vision - ruimte voor verbeelding
Y1  - 2010
SN  - 978-90-5856-357-6
N1  - Texte Engl. und Niederländ.
PB  - Stichting Kunstboek
CY  - Oostkamp
ER  - 
TY  - CHAP
A1  - Vladova, Gergana
A1  - Ullrich, André
A1  - Sultanow, Eldar
A1  - Tobolla, Marinho
A1  - Sebrak, Sebastian
A1  - Czarnecki, Christian
A1  - Brockmann, Carsten
T1  - Visual analytics for knowledge management
T2  - INFORMATIK 2023 - Designing Futures: Zukünfte gestalten
N2  - The management of knowledge in organizations considers both established long-term processes and cooperation in agile project teams. Since knowledge can be both tacit and explicit, its transfer from the individual to the organizational knowledge base poses a challenge in organizations. This challenge increases when the fluctuation of knowledge carriers is exceptionally high. Especially in large projects in which external consultants are involved, there is a risk that critical, company-relevant knowledge generated in the project will leave the company with the external knowledge carrier and thus be lost. In this paper, we show the advantages of an early warning system for knowledge management to avoid this loss. In particular, the potential of visual analytics in the context of knowledge management systems is presented and discussed. We present a project for the development of a business-critical software system and discuss the first implementations and results.
Y1  - 2023
SN  - 978-3-88579-731-9
U6  - https://doi.org/10.18420/inf2023_187
SN  - 1617-5468
N1  - INFORMATIK 2023, 26. - 29. September 2023, Berlin
SP  - 1851
EP  - 1870
PB  - GI - Gesellschaft für Informatik
CY  - Bonn
ER  - 
TY  - JOUR
A1  - Elsen, Ingo
A1  - Kraiss, Karl-Friedrich
A1  - Krumbiegel, Dirk
A1  - Walter, Peter
A1  - Wickel, Jochen
T1  - Visual information retrieval for 3D product identification: a midterm report
JF  - KI - Künstliche Intelligenz
Y1  - 1999
SN  - 1610-1987
SN  - 0933-1875
VL  - 13
IS  - 1
SP  - 64
EP  - 67
PB  - Springer
CY  - Berlin
ER  - 
TY  - BOOK
A1  - Digel, Ilya
A1  - Zhubanova, Azhar Ahmetovna
A1  - Akimbekov, Nuraly S.
T1  - Visual Virology
Y1  - 2012
SN  - 978-601-247-298-1
N1  - Text kasachisch, russisch, englisch
CY  - Almaty
ER  - 
TY  - JOUR
A1  - Miyamoto, Ko-ichiro
A1  - Bing, Yu
A1  - Wagner, Torsten
A1  - Yoshinobu, Tatsuo
A1  - Schöning, Michael Josef
T1  - Visualization of Defects on a Cultured Cell Layer by Utilizing Chemical Imaging Sensor
JF  - Procedia Engineering
N2  - The chemical imaging sensor is a field-effect sensor which is able to visualize both the distribution of ions (in LAPS mode) and the distribution of impedance (in SPIM mode) inthe sample. In this study, a novel wound-healing assay is proposed, in which the chemical imaging sensor operated in SPIM mode is applied to monitor the defect of a cell layer brought into proximity of the sensing surface.A reduced impedance inside the defect, which was artificially formed ina cell layer, was successfully visualized in a photocurrent image.
Y1  - 2015
U6  - https://doi.org/10.1016/j.proeng.2015.08.806
SN  - 1877-7058
N1  - Part of special issue "Eurosensors 2015"
VL  - 120
SP  - 936
EP  - 939
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Miyamoto, Ko-ichiro
A1  - Hirayama, Yuji
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Visualization of enzymatic reaction in a microfluidic channel using chemical imaging sensor
JF  - Electrochimica acta
Y1  - 2013
SN  - 1873-3859 (E-Journal); 0013-4686 (Print)
SP  - Publ. online
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Kramer, Pia
A1  - Bragard, Michael
A1  - Ritz, Thomas
A1  - Ferfer, Ute
A1  - Schiffers, Tim
T1  - Visualizing, Enhancing and Predicting Students’ Success through ECTS Monitoring
T2  - 2024 IEEE Global Engineering Education Conference (EDUCON)
N2  - This paper serves as an introduction to the ECTS monitoring system and its potential applications in higher education. It also emphasizes the potential for ECTS monitoring to become a proactive system, supporting students by predicting academic success and identifying groups of potential dropouts for tailored support services. The use of the nearest neighbor analysis is suggested for improving data analysis and prediction accuracy.
KW  - Monitoring
KW  - Engineering education
KW  - Data visualization
KW  - Accuracy
KW  - Data analysis
Y1  - 2024
U6  - https://doi.org/10.1109/EDUCON60312.2024.10578652
SN  - 2165-9559
SN  - 2165-9567 (eISSN)
N1  - 2024 IEEE Global Engineering Education Conference (EDUCON), 08-11 May 2024, Kos Island, Greece
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - CHAP
A1  - Akimbekov, Nuraly S.
A1  - Digel, Ilya
A1  - Sherelkhan, Dinara K.
A1  - Razzaque, Mohammed S.
T1  - Vitamin D and Phosphate Interactions in Health and Disease
T2  - Phosphate Metabolism
N2  - Vitamin D plays an essential role in calcium and inorganic phosphate (Pi) homeostasis, maintaining their optimal levels to assure adequate bone mineralization. Vitamin D, as calcitriol (1,25(OH)2D), not only increases intestinal calcium and phosphate absorption but also facilitates their renal reabsorption, leading to elevated serum calcium and phosphate levels. The interaction of 1,25(OH)2D with its receptor (VDR) increases the efficiency of intestinal absorption of calcium to 30–40% and phosphate to nearly 80%. Serum phosphate levels can also influence 1,25 (OH)2D and fibroblast growth factor 23 (FGF23) levels, i.e., higher phosphate concentrations suppress vitamin D activation and stimulate parathyroid hormone (PTH) release, while a high FGF23 serum level leads to reduced vitamin D synthesis. In the vitamin D-deficient state, the intestinal calcium absorption decreases and the secretion of PTH increases, which in turn causes the stimulation of 1,25(OH)2D production, resulting in excessive urinary phosphate loss. Maintenance of phosphate homeostasis is essential as hyperphosphatemia is a risk factor of cardiovascular calcification, chronic kidney diseases (CKD), and premature aging, while hypophosphatemia is usually associated with rickets and osteomalacia. This chapter elaborates on the possible interactions between vitamin D and phosphate in health and disease.
KW  - Vitamin D
KW  - PTH
KW  - Phosphate
KW  - FGF23
KW  - Klotho
Y1  - 2022
SN  - 978-3-030-91621-3
U6  - https://doi.org/10.1007/978-3-030-91623-7_5
SP  - 37
EP  - 46
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Akimbekov, Nuraly S.
A1  - Digel, Ilya
A1  - Sherelkhan, Dinara K.
A1  - Lutfor, Afzalunnessa B.
A1  - Razzaque, Mohammed S.
T1  - Vitamin D and the Host-Gut Microbiome: A Brief Overview
JF  - Acta Histochemica et Cytochemica
N2  - There is a growing body of evidence for the effects of vitamin D on intestinal host-microbiome interactions related to gut dysbiosis and bowel inflammation. This brief review highlights the potential links between vitamin D and gut health, emphasizing the role of vitamin D in microbiological and immunological mechanisms of inflammatory bowel diseases. A comprehensive literature search was carried out in PubMed and Google Scholar using combinations of keywords “vitamin D,” “intestines,” “gut microflora,” “bowel inflammation”. Only articles published in English and related to the study topic are included in the review. We discuss how vitamin D (a) modulates intestinal microbiome function, (b) controls antimicrobial peptide expression, and (c) has a protective effect on epithelial barriers in the gut mucosa. Vitamin D and its nuclear receptor (VDR) regulate intestinal barrier integrity, and control innate and adaptive immunity in the gut. Metabolites from the gut microbiota may also regulate expression of VDR, while vitamin D may influence the gut microbiota and exert anti-inflammatory and immune-modulating effects. The underlying mechanism of vitamin D in the pathogenesis of bowel diseases is not fully understood, but maintaining an optimal vitamin D status appears to be beneficial for gut health. Future studies will shed light on the molecular mechanisms through which vitamin D and VDR interactions affect intestinal mucosal immunity, pathogen invasion, symbiont colonization, and antimicrobial peptide expression.
Y1  - 2020
U6  - https://doi.org/10.1267/ahc.20011
SN  - 1347-5800
VL  - 53
IS  - 3
SP  - 33
EP  - 42
PB  - Japan Society of Histochemistry and Cytochemistry
CY  - Osaka
ER  - 
TY  - JOUR
A1  - Emons, H.
A1  - Baade, A.
A1  - Schöning, Michael Josef
T1  - Voltammetric determination of heavy metals in microvolumes of rain water
JF  - Electroanalysis. 12 (2000), H. 15
Y1  - 2000
SN  - 1040-0397
SP  - 1171
EP  - 1176
ER  - 
TY  - JOUR
A1  - Emons, H.
A1  - Glück, O.
A1  - Hüllenkremer, B.
A1  - Schöning, Michael Josef
T1  - Voltohmmetry as an alternative detection method at polycrystalline metal film electrodes
JF  - Electroanalysis. 13 (2001), H. 8-9
Y1  - 2001
SN  - 1040-0397
SP  - 677
EP  - 680
ER  - 
TY  - JOUR
A1  - Schöning, Michael Josef
A1  - Hüllenkremer, B.
A1  - Glück, O.
A1  - Lüth, H.
A1  - Emons, H.
T1  - Voltohmmetry – a novel sensing principle for heavy metal determination in aqueous solutions
JF  - Sensors and Actuators B. 78 (2001), H. 1-3
Y1  - 2001
SN  - 0925-4005
SP  - 275
EP  - 280
ER  - 
TY  - JOUR
A1  - Emons, H.
A1  - Glück, O.
A1  - Schöning, Michael Josef
T1  - Voltohmmetry – An alternative detection principle at ultrathin metal electrodes in solution
JF  - Chemical and biological sensors and analytical methods : proceedings of the international symposium / Sensor, Physical Electrochemistry, and Organic and Biological Electrochemistry Divisions. Ed.: M. Butler
Y1  - 2001
SN  - 1-56677-351-2
N1  - International Symposium: Chemical and Biological Sensors and Analytical Methods ; (2 : 2001.)
SP  - 1
EP  - 3
PB  - Electrochemical Society
CY  - Pennington, NJ
ER  - 
TY  - CHAP
A1  - Karimi, Iman
A1  - Butenweg, Christoph
A1  - Toll, Britta
T1  - Vulnerability assessment of industrial facilities
T2  - Proceedings of the Tenth International Conference on Civil, Structural and Environmental Engineering Computing : [Rome, Italy, 30. August - 2. September 2005] / ed. by B. H. V. Topping
Y1  - 2005
SN  - 1-905088-00-0
U6  - https://doi.org/10.4203/ccp.81.34
SP  - 34, 73
EP  - 75
PB  - Civil-Comp Press
CY  - Stirling
ER  - 
TY  - JOUR
A1  - Schirra, Julian
A1  - Bissonnette, William
A1  - Bramesfeld, Götz
T1  - Wake-model effects on induced drag prediction of staggered boxwings
JF  - Aerospace
Y1  - 2018
U6  - https://doi.org/10.3390/aerospace5010014
SN  - 2226-4310
VL  - 5
IS  - 1
ER  - 
TY  - JOUR
A1  - Meliß, Michael
A1  - Neskakis, A.
A1  - Plettner-Marliani, J.
A1  - Lange, C.
A1  - Hövelmann, A.
A1  - Schumacher, J.
T1  - Waste water recycling supplied by renewable energies : basic conditions and possible treatment technologies
JF  - Renewable energy. Vol. 14 (1998), iss. 1-4. 6th Arab International Solar Energy Conference: Bringing Solar Energy into the Daylight, Muscat, Sultanate of Oman, 29.03.-01.04.1998
Y1  - 1998
SN  - 1879-0682 (E-Book); 0960-1481 (Print)
SP  - 325
EP  - 331
ER  - 
TY  - CHAP
A1  - Bung, Daniel Bernhard
A1  - Oertel, Mario
T1  - Wave breaking over a submerged horizontal plate: Optical Flow, LES and RANS
T2  - E-proceedings of the 38th IAHR World Congress  September 1-6, 2019, Panama City, Panama
Y1  - 2019
U6  - https://doi.org/10.3850/38WC092019-0509
SP  - 3690
EP  - 3698
ER  -