TY - GEN A1 - Martin, Conrad Steven A1 - Frauenrath, Tobias A1 - Zerdem, Celal A1 - Renz, Wolfgang A1 - Niendorf, Thoralf T1 - Evaluation of Magneto Alert Sensor (MALSE) to Improve MR Safety by Decreasing the Incidence of Ferromagnetic Projectile Accidents T2 - 2011 ISMRM Annual Meeting Proceedings N2 - The magnetic forces of fringe magnetic fields of MR systems on ferromagnetic components can impose a severe patient, occupational health and safety hazard. MRI accidents are listed as number 9 of the top 10 risks in modern medicine. With the advent of ultrahigh field MR systems including passively shielded magnet versions, this risk, commonly known as the missile or projectile effect is even more pronounced. A strategy employing magnetic field sensors which can be attached to ferromagnetic objects that are commonly used in a clinical environment is conceptually appealing for the pursuit of reducing the risk of ferromagnetic projectile accidents. Y1 - 2011 SN - 1545-4428 N1 - ISMRM 19th Annual Meeting & Exhibition, 7-13 May 2011, Montreal, Quebec, Canada ER - TY - GEN A1 - Frauenrath, Tobias A1 - de Geyer d'Orth, Thibaut A1 - Niendorf, Thoralf T1 - Assessment of Accuracy & Reproducibility of ECG, Pulse Oximetry & Phonocardiogram Gating of Cardiac MRI at 7T T2 - 2011 ISMRM Annual Meeting Proceedings N2 - At (ultra)high magnetic fields the artifact sensitivity of ECG recordings increases. This bears the risk of R-wave mis-registration which has been consistently reported for ECG triggered CMR at 7.0T. Realizing the constraints of conventional ECG, acoustic cardiac triggering (ACT) has been proposed. The clinical ACT has not been carefully examined yet. For this reason, this work scrutinizes the suitability, accuracy and reproducibility of ACT for CMR at 7.0T. For this purpose, the trigger reliability and trigger detection variance are examined together with an qualitative and quantitative assessment of image quality of the heart at 7.0T. Y1 - 2011 SN - 1545-4428 N1 - ISMRM 19th Annual Meeting & Exhibition, 7-13 May 2011, Montreal, Quebec, Canada ER - TY - GEN A1 - Frauenrath, Tobias A1 - Dieringer, Matthias A1 - Patel, Nishant A1 - Zerdem, Celal A1 - Hentschel, Jan A1 - Renz, Wolfgang A1 - Niendorf, Thoralf T1 - From Artifact to Merit: Cardiac Gated MRI at 7T & 3T using Magneto-Hydrodynamic Effects for Synchronization T2 - 2011 ISMRM Annual Meeting Proceedings N2 - ECG is corrupted by magneto-hydrodynamic effects at higher magnetic field strength. Artifacts in the ECG trace and severe T-wave elevation might be mis-interpreted as R-waves. MHD being inherently sensitive to blood flow and blood velocity provides an alternative approach for cardiac gating, even in peripheral target areas far away from the commonly used upper torso positions of ECG electrodes. This feature would be very beneficial to address traveling time induced motion artifacts and trigger latency related issues raised by ECG-gated peripheral MR angiography. For all those reasons, this work proposes the use of MHD-trigger for cardiac gated MR. Y1 - 2011 SN - 1545-4428 N1 - ISMRM 19th Annual Meeting & Exhibition, 7-13 May 2011, Montreal, Quebec, Canada ER - TY - JOUR A1 - Dieringer, Matthias A. A1 - Renz, Wolfgang A1 - Lindel, Tomasz D. A1 - Seifert, Frank A1 - Frauenrath, Tobias A1 - von Knobelsdorf-Brenkenhoff, Florian A1 - Waiczies, Helmar A1 - Hoffmann, Werner A1 - Rieger, Jan A1 - Pfeiffer, Harald A1 - Ittermann, Bernd A1 - Schulz-Menger, Jeanette A1 - Niendorf, Thoralf T1 - Design and application of a four-channel transmit/receive surface coil for functional cardiac imaging at 7T JF - Journal of Magnetic Resonance Imaging N2 - Purpose To design and evaluate a four-channel cardiac transceiver coil array for functional cardiac imaging at 7T. Materials and Methods A four-element cardiac transceiver surface coil array was developed with two rectangular loops mounted on an anterior former and two rectangular loops on a posterior former. specific absorption rate (SAR) simulations were performed and a Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-1 calibration method was applied prior to obtain 2D FLASH CINE (mSENSE, R = 2) images from nine healthy volunteers with a spatial resolution of up to 1 × 1 × 2.5 mm3. Results Tuning and matching was found to be better than 10 dB for all subjects. The decoupling (S21) was measured to be >18 dB between neighboring loops, >20 dB for opposite loops, and >30 dB for other loop combinations. SAR values were well within the limits provided by the IEC. Imaging provided clinically acceptable signal homogeneity with an excellent blood-myocardium contrast applying the Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-2 calibration approach. Conclusion A four-channel cardiac transceiver coil array for 7T was built, allowing for cardiac imaging with clinically acceptable signal homogeneity and an excellent blood-myocardium contrast. Minor anatomic structures, such as pericardium, mitral, and tricuspid valves and their apparatus, as well as trabeculae, were accurately delineated. Y1 - 2011 U6 - https://doi.org/10.1002/jmri.22451 SN - 1522-2586 VL - 33 IS - 3 SP - 736 EP - 741 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Martin, Conrad A1 - Frauenrath, Tobias A1 - Özerdem, Celal A1 - Renz, Wolfgang A1 - Niendorf, Thoralf T1 - Development and evaluation of a small and mobile Magneto Alert Sensor (MALSE) to support safety requirements for magnetic resonance imaging JF - European Radiology N2 - Objective The purpose of this study is to (i) design a small and mobile Magnetic field ALert SEnsor (MALSE), (ii) to carefully evaluate its sensors to their consistency of activation/deactivation and sensitivity to magnetic fields, and (iii) to demonstrate the applicability of MALSE in 1.5 T, 3.0 T and 7.0 T MR fringe field environments. Methods MALSE comprises a set of reed sensors, which activate in response to their exposure to a magnetic field. The activation/deactivation of reed sensors was examined by moving them in/out of the fringe field generated by 7TMR. Results The consistency with which individual reed sensors would activate at the same field strength was found to be 100% for the setup used. All of the reed switches investigated required a substantial drop in ambient magnetic field strength before they deactivated. Conclusions MALSE is a simple concept for alerting MRI staff to a ferromagnetic object being brought into fringe magnetic fields which exceeds MALSEs activation magnetic field. MALSE can easily be attached to ferromagnetic objects within the vicinity of a scanner, thus creating a barrier for hazardous situations induced by ferromagnetic parts which should not enter the vicinity of an MR-system to occur. KW - MRI KW - MR safety KW - Magneto alert sensor KW - High field MRI KW - Uktrahigh field MRI Y1 - 2011 U6 - https://doi.org/10.1007/s00330-011-2153-z SN - 1432-1084 VL - 21 SP - 2187 EP - 2192 PB - Springer CY - Berlin, Heidelberg ER - TY - CHAP A1 - Czarnecki, Christian A1 - Winkelmann, Axel A1 - Spiliopoulou, Myra ED - Pokorny, Jaroslav ED - Repa, Vaclav ED - Richta, Karel ED - Wojtkowski, Wita ED - Linger, Henry ED - Barry, Chris ED - Lang, Michael T1 - Making business systems in the telecommunication industry more customer-oriented T2 - Information Systems Development : Business Systems and Services: Modeling and Development N2 - Market changes have forced telecommunication companies to transform their business. Increased competition, short innovation cycles, changed usage patterns, increased customer expectations and cost reduction are the main drivers. Our objective is to analyze to what extend transformation projects have improved the orientation towards the end-customers. Therefore, we selected 38 real-life case studies that are dealing with customer orientation. Our analysis is based on a telecommunication-specific framework that aligns strategy, business processes and information systems. The result of our analysis shows the following: transformation projects that aim to improve the customer orientation are combined with clear goals on costs and revenue of the enterprise. These projects are usually directly linked to the customer touch points, but also to the development and provisioning of products. Furthermore, the analysis shows that customer orientation is not the sole trigger for transformation. There is no one-fits-all solution; rather, improved customer orientation needs aligned changes of business processes as well as information systems related to different parts of the company. KW - Business Process KW - Customer Orientation KW - Enterprise Architecture KW - Transformation Project KW - Telecommunication Industry Y1 - 2011 SN - 978-1-4419-9645-9 (Print) SN - 978-1-4419-9790-6 (Online) U6 - https://doi.org/10.1007/978-1-4419-9790-6_14 N1 - 19th International Conference on Information Systems Development held in Prague, Czech Republic, August 25 - 27, 2010. SP - 169 EP - 180 PB - Springer CY - New York ER - TY - CHAP A1 - Dachwald, Bernd A1 - Xu, Changsheng A1 - Feldmann, Marco A1 - Plescher, Engelbert T1 - IceMole : Development of a novel subsurface ice probe and testing of the first prototype on the Morteratsch Glacier T2 - EGU General Assembly 2011 Vienna | Austria | 03 – 08 April 2011 N2 - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth). Y1 - 2011 ER - TY - CHAP A1 - Loeb, Horst W. A1 - Schartner, Karl-Heinz A1 - Dachwald, Bernd A1 - Ohndorf, Andreas A1 - Seboldt, Wolfgang T1 - An Interstellar – Heliopause mission using a combination of solar/radioisotope electric propulsion T2 - Presented at the 32nd International Electric Propulsion Conference N2 - There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft travelling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by ESA.Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope electric propulsion. As a further alternative, we here investigate a combination of solar-electric propulsion and radioisotope-electric propulsion. The solar-electric propulsion stage consists of six 22 cm diameter “RIT-22”ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW BOM is provided by a light-weight solar array. The REP-stage consists of four space-proven 10 cm diameter “RIT-10” ion thrusters that will be operating one after the other for 9 yrs in total. Four advanced radioisotope generators provide 648 W at BOM. The scientific instrument package is oriented at earlier studies. For its mass and electric power requirement 35 kg and 35 W are assessed, respectively. Optimized trajectory calculations, treated in a separate contribution, are based on our “InTrance” method.The program yields a burn out of the REP stage in a distance of 79.6 AU for a usage of 154 kg of Xe propellant. With a C3 = 45,1 (km/s)2 a heliocentric probe velocity of 10 AU/yr is reached at this distance, provided a close Jupiter gravity assist adds a velocity increment of 2.7 AU/yr. A transfer time of 23.8 yrs results for this scenario requiring about 450 kg Xe for the SEP stage, jettisoned at 3 AU. We interpret the SEP/REP propulsion as a competing alternative to solar sail and ballistic/REP propulsion. Omiting a Jupiter fly-by even allows more launch flexibility, leaving the mission duration in the range of the ESA specification. Y1 - 2011 N1 - 32nd International Electric Propulsion Conference, 11-15 September. Wiesbaden, Germany SP - 1 EP - 7 ER - TY - CHAP A1 - Ohndorf, Andreas A1 - Dachwald, Bernd A1 - Seboldt, Wolfgang A1 - Schartner, Karl-Heinz T1 - Flight times to the heliopause using a combination of solar and radioisotope electric propulsion T2 - 32nd International Electric Propulsion Conference N2 - We investigate the interplanetary flight of a low-thrust space probe to the heliopause,located at a distance of about 200 AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of allistic and electrically propelled flight legs, we have investigated whether the set flight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the first stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol,using Artificial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks’ parameter set. Based on a parameter space study, in which the number of thrust units, the unit’s specific impulse, and the relative size of the solar power generator were varied, we have chosen one configuration as reference. The transfer time of this reference configuration was 29.6 years and the fastest one, which is technically more challenging, still required 28.3 years. As all flight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher-provided hyperbolic excess energy up to 49 km2/s2. The resulting minimal flight time for the reference configuration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is flexible enough to allow a launch every year. The inclusion of a fly-by at Jupiter finally resulted in a flight time of 23.8 years,which is below the set transfer-time limit. However, compared to the 27.5-year transfer,this mission design has a significantly reduced launch window and mission flexibility if the escape direction is restricted to the heliosphere’s “nose". KW - low-thrust trajectory optimization KW - heliosphere KW - ion propulsion Y1 - 2011 N1 - IEPC-2011-051 32nd International Electric Propulsion Conference,September 11–15, 2011 Wiesbaden, Germany SP - 1 EP - 12 ER - TY - JOUR A1 - Nguyen-Xuan, H. A1 - Rabczuk, T. A1 - Nguyen-Thoi, T. A1 - Tran, Thanh Ngoc A1 - Nguyen-Thanh, N. T1 - Computation of limit and shakedown loads using a node-based smoothed finite element method JF - International Journal for Numerical Methods in Engineering N2 - This paper presents a novel numerical procedure for computing limit and shakedown loads of structures using a node-based smoothed FEM in combination with a primal–dual algorithm. An associated primal–dual form based on the von Mises yield criterion is adopted. The primal-dual algorithm together with a Newton-like iteration are then used to solve this associated primal–dual form to determine simultaneously both approximate upper and quasi-lower bounds of the plastic collapse limit and the shakedown limit. The present formulation uses only linear approximations and its implementation into finite element programs is quite simple. Several numerical examples are given to show the reliability, accuracy, and generality of the present formulation compared with other available methods. Y1 - 2011 U6 - https://doi.org/10.1002/nme.3317 SN - 1097-0207 VL - 90 IS - 3 SP - 287 EP - 310 PB - Wiley CY - Weinheim ER - TY - CHAP A1 - Matcha, Heike A1 - Barczik, Günter ED - Valena, Tomas ED - Avermaete, Tom ED - Vrachliotis, Georg T1 - Mass Diversity: Individualized housing via parametric typology T2 - Structuralism Reloaded? Rule-Based Design in Architecture and Urbanism Y1 - 2011 SN - 978-3-936681-47-5 SP - 354 EP - 358 PB - Edition Axel Menges CY - Fellbach ER - TY - THES A1 - Behbahani, Mehdi T1 - Modeling and Simulation of Shear-Dependent Platelet Reactions in Blood Vessels and Blood-Contacting Medical Devices Y1 - 2011 SN - 978-3-8439-0134-5 PB - Verlag Dr. Hut CY - München ER - TY - THES A1 - Pham, Phu Tinh T1 - Upper bound limit and shakedown analysis of elastic-plastic bounded linearly kinematic hardening structures Y1 - 2011 N1 - Aachen, Techn. Hochsch., Diss., 2011 PB - RWTH Aachen University CY - Aachen ER - TY - CHAP A1 - Becker, Jörg A1 - Eggert, Mathias A1 - Winkelmann, Axel A1 - Knackstedt, Ralf T1 - Towards a Contingency Theory based Model of the Influence of Regulation on MIS T2 - Proceedings of the Seventeenth Americas Conference on Information Systems, Detroit, Michigan August 4th -7 th 2011 Y1 - 2011 ER - TY - CHAP A1 - Becker, Jörg A1 - Bergener, Philipp A1 - Delfmann, Patrick A1 - Eggert, Mathias A1 - Weiss, Burkhard T1 - Supporting Business Process Compliance in Financial Institutions - A Model-Driven Approach T2 - Proceedings of the 10th International Conference on Wirtschaftsinformatik : 16 - 18 February 2011, Zurich, Switzerland Y1 - 2011 N1 - Wirtschaftsinformatik Proceedings 2011. 75. SP - 355 EP - 364 ER - TY - CHAP A1 - Becker, Jörg A1 - Bergener, Philipp A1 - Breuker, Dominic A1 - Delfmann, Patrick A1 - Eggert, Mathias T1 - An Efficient Business Process Compliance Checking Approach T2 - Governance and Sustainability in Information Systems. Managing the Transfer and Diffusion of IT : IFIP WG 8.6 International Working Conference, Hamburg, Germany, September 22-24, 2011. Proceedings Y1 - 2011 U6 - https://doi.org/10.1007/978-3-642-24148-2_19 SP - 282 EP - 287 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Bialonski, Stephan A1 - Wendler, Martin A1 - Lehnertz, Klaus T1 - Unraveling spurious properties of interaction networks with tailored random networks JF - Plos one N2 - We investigate interaction networks that we derive from multivariate time series with methods frequently employed in diverse scientific fields such as biology, quantitative finance, physics, earth and climate sciences, and the neurosciences. Mimicking experimental situations, we generate time series with finite length and varying frequency content but from independent stochastic processes. Using the correlation coefficient and the maximum cross-correlation, we estimate interdependencies between these time series. With clustering coefficient and average shortest path length, we observe unweighted interaction networks, derived via thresholding the values of interdependence, to possess non-trivial topologies as compared to Erdös-Rényi networks, which would indicate small-world characteristics. These topologies reflect the mostly unavoidable finiteness of the data, which limits the reliability of typically used estimators of signal interdependence. We propose random networks that are tailored to the way interaction networks are derived from empirical data. Through an exemplary investigation of multichannel electroencephalographic recordings of epileptic seizures – known for their complex spatial and temporal dynamics – we show that such random networks help to distinguish network properties of interdependence structures related to seizure dynamics from those spuriously induced by the applied methods of analysis. Y1 - 2011 U6 - https://doi.org/10.1371/journal.pone.0022826 VL - 6 IS - 8 PB - Plos CY - San Francisco ER - TY - CHAP A1 - Muffler, Kai A1 - Poth, Sabastian A1 - Sieker, Tim A1 - Tippkötter, Nils A1 - Ulber, Roland A1 - Sell, Dieter ED - Moo-Young, Murray T1 - Bio-feedstocks T2 - Comprehensive biotechnology : principles and practices in industry, agcriculture, medicine and the environment. Volume 2: Engineering fundamentals of biotechnology Y1 - 2011 SN - 978-0-444-53352-4 U6 - https://doi.org/10.1016/B978-0-08-088504-9.00088-X SP - 93 EP - 101 PB - Elsevier CY - Amsterdam ET - 2. edition ER - TY - CHAP A1 - Hahn, Thomas A1 - Kelly, Svenja A1 - Muffler, Kai A1 - Tippkötter, Nils A1 - Ulber, Roland ED - Hans-Jörg, Bart ED - Pilz, Stephan T1 - Extraction of lignocellulose and algae for the production of bulk and fine chemicals T2 - Industrial scale natural products extraction Y1 - 2011 SN - 978-3-527-32504-7 (Print) SN - 978-3-527-63512-2 (Online) U6 - https://doi.org/10.1002/9783527635122 SP - 221 EP - 245 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Poth, Sebastian A1 - Monzon, Magaly A1 - Tippkötter, Nils A1 - Ulber, Roland T1 - Lignocellulosic biorefinery: Process integration of hydrolysis and fermentation (SSF process) JF - Holzforschung N2 - The aim of the present work is the process integration and the optimization of the enzymatic hydrolysis of wood and the following fermentation of the products to ethanol. The substrate is a fiber fraction obtained by organosolv pre-treatment of beech wood. For the ethanol production, a co-fermentation by two different yeasts (Saccharomyces cerevisiae and Pachysolen tannophilus) was carried out to convert glucose as well as xylose. Two approaches has been followed: 1. A two step process, in which the hydrolysis of the fiber fraction and the fermentation to product are separated from each other. 2. A process, in which the hydrolysis and the fermentation are carried out in one single process step as simultaneous saccharification and fermentation (SSF). Following the first approach, a yield of about 0.15 g ethanol per gram substrate can be reached. Based on the SSF, one process step can be saved, and additionally, the gained yield can be raised up to 0.3 g ethanol per gram substrate. Y1 - 2011 N1 - 11th EWLP, Hamburg, Germany, August 16–19, 2010 VL - 65 IS - 5 SP - 633 EP - 637 PB - De Gruyter CY - Berlin ER -