TY  - JOUR
A1  - Gerhards, M.
A1  - Skorupa, Sascha
A1  - Sander, Volker
A1  - Belloum, Adam
A1  - Vesunin, D.
A1  - Benabdelkader, A.
T1  - HisT/PLIER : A Two-Fold Provenance Approach for Grid-Enabled Scientific Workflows Using WS-VLAM
JF  - 12th IEEE/ACM International Conference on Grid Computing (GRID), 2011
Y1  - 2011
U6  - https://doi.org/10.1109/Grid.2011.39
SP  - 224
EP  - 225
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Heinrichs, U.
A1  - Pietrzyk, Uwe
A1  - Ziemons, Karl
T1  - Design optimization of the PMT-ClearPET prototypes based on simulation studies with GEANT3
JF  - IEEE Transactions on Nuclear Science
N2  - Within the Crystal Clear Collaboration (CCC), four centers are developing second generation high performance small animal positron emission tomography (PET) scanners for different kinds of animals and medical applications. The first prototypes are photomultiplier tube (PMT)-based systems including depth of interaction (DOI) detection by using a phoswich layer of lutetium oxyorthosilicate (LSO) and lutetium yttrium aluminum perovskite (LuYAP). The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in fields of view (FOVs) caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN, Geneva, Switzerland) was used.
Y1  - 2003
SN  - 0018-9499
VL  - 50
IS  - 5
SP  - 1428
EP  - 1432
ER  - 
TY  - JOUR
A1  - Hirschfeld, Julian A.
A1  - Lustfeld, Hans
A1  - Reißel, Martin
A1  - Steffen, Bernhard
T1  - A novel scheme for precise diagnostics and effective stabilization of currents in a fuel cell stack
JF  - International Journal of Energy Research
N2  - A novel scheme for detecting inhomogeneous internal currents in a fuel cell stack is presented. In this paper the scheme is investigated for the case that the flow field plates consist of graphite. Then plates of high conductivity, e.g. aluminium between the flow field plates together with small slits in these plates have three effects: (a) Whenever a local inhomogeneity of the electric current occurs at a particular cell in the stack, this will induce a surface current close to that cell perpendicular to the averaged current. This current can be detected. (b) The plates of high conductivity completely prevent the inhomogeneities from spreading to neighbouring cells. (c) Even at the particular cell the inhomogeneity is suppressed as far as possible. Thus this scheme leads to much better diagnostic possibilities and at the same time reduces electric instabilities to an extent, where they probably become harmless. This scheme will first be explained for a simple model to clarify the idea. However, very precise three dimensional computations using realistic parameters are presented, corroborating the results of the simple model.
Y1  - 2010
U6  - https://doi.org/10.1002/er.1662
SN  - 0363-907X
VL  - 34
IS  - 3
SP  - 293
EP  - 301
PB  - Wiley
CY  - London
ER  - 
TY  - JOUR
A1  - Hirschfeld, Julian A.
A1  - Lustfeld, Hans
A1  - Reißel, Martin
A1  - Steffen, Bernhard
T1  - Tomographic diagnostics of current distributions in a fuel cell stack
JF  - International Journal of Energy Research
N2  - A novel tomographic scheme for analysing the state of any single membrane electrode assembly (MEA) in a stack is suggested. Plates of very high conductivity placed between every fuel cell and slitted in an appropriate manner cause surface currents at well-defined locations of the stack. We show that knowing these surface currents, information about anomalies of the currents in a MEA can be obtained using the methods of tomography. The results are mathematically not unique. However, when assuming plausible defect structures, one can exclude improbable deficiencies by applying a special form of simulated annealing. We present numerical calculations of typical examples demonstrating that the essential defects of the MEA in any single cell of the stack can be detected and their extent can be determined.
Y1  - 2010
U6  - https://doi.org/10.1002/er.1634
SN  - 0363-907X
VL  - 34
IS  - 3
SP  - 284
EP  - 292
PB  - Wiley
CY  - London
ER  -