TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Orzada, Stephan
A1  - Flöser, Martina
A1  - Rietsch, Stefan H. G.
A1  - Quick, Harald H.
A1  - Ladd, Mark E.
A1  - Bitz, Andreas
T1  - Performance analysis of integrated RF microstrip transmit antenna arrays with high channel count for body imaging at 7 T
JF  - NMR in Biomedicine
N2  - The aim of the current study was to investigate the performance of integrated RF
transmit arrays with high channel count consisting of meander microstrip antennas
for body imaging at 7 T and to optimize the position and number of transmit ele-
ments. RF simulations using multiring antenna arrays placed behind the bore liner
were performed for realistic exposure conditions for body imaging. Simulations were
performed for arrays with as few as eight elements and for arrays with high channel
counts of up to 48 elements. The B1+ field was evaluated regarding the degrees of
freedom for RF shimming in the abdomen. Worst-case specific absorption rate
(SARwc ), SAR overestimation in the matrix compression, the number of virtual obser-
vation points (VOPs) and SAR efficiency were evaluated. Constrained RF shimming
was performed in differently oriented regions of interest in the body, and the devia-
tion from a target B1+ field was evaluated. Results show that integrated multiring
arrays are able to generate homogeneous B1+ field distributions for large FOVs, espe-
cially for coronal/sagittal slices, and thus enable body imaging at 7 T with a clinical
workflow; however, a low duty cycle or a high SAR is required to achieve homoge-
neous B1+ distributions and to exploit the full potential. In conclusion, integrated
arrays allow for high element counts that have high degrees of freedom for the pulse
optimization but also produce high SARwc , which reduces the SAR accuracy in the
VOP compression for low-SAR protocols, leading to a potential reduction in array
performance. Smaller SAR overestimations can increase SAR accuracy, but lead to a
high number of VOPs, which increases the computational cost for VOP evaluation
and makes online SAR monitoring or pulse optimization challenging. Arrays with
interleaved rings showed the best results in the study.
KW  - body imaging at UHF MRI
KW  - integrated transmit coil arrays
KW  - VOP compression
Y1  - 2021
U6  - https://doi.org/10.1002/nbm.4515
SN  - 0952-3480 (ISSN)
SN  - 1099-1492 (eISSN)
VL  - 34
IS  - 7
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - CHAP
A1  - Becker, Tim
A1  - Bragard, Michael
T1  - Low-Voltage DC Training Lab for Electric Drives - Optimizing the Balancing Act Between High Student Throughput and Individual Learning Speed
T2  - 2024 IEEE Global Engineering Education Conference (EDUCON)
N2  - After a brief introduction of conventional laboratory structures, this work focuses on an innovative and universal approach for a setup of a training laboratory for electric machines and drive systems. The novel approach employs a central 48 V DC bus, which forms the backbone of the structure. Several sets of DC machine, asynchronous machine and synchronous machine are connected to this bus. The advantages of the novel system structure are manifold, both from a didactic and a technical point of view: Student groups can work on their own performance level in a highly parallelized and at the same time individualized way. Additional training setups (similar or different) can easily be added. Only the total power dissipation has to be provided, i.e. the DC bus balances the power flow between the student groups. Comparative results of course evaluations of several cohorts of students are shown.
KW  - Synchronous machines
KW  - Power dissipation
KW  - Throughput
KW  - Low voltage
KW  - DC machines
KW  - Manifolds
KW  - Training
Y1  - 2024
U6  - https://doi.org/10.1109/EDUCON60312.2024.10578902
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  - Rütters, René
A1  - Bragard, Michael
A1  - Dolls, Sarah
T1  - The Inverted Rotary Pendulum: Facilitating Practical Teaching in Advanced Control Engineering
T2  - 2024 IEEE Global Engineering Education Conference (EDUCON)
N2  - This paper outlines a practical approach to teach control engineering principles, with an inverted rotary pendulum, serving as an illustrative example. It shows how the pendulum is embedded in an advanced course of control engineering. This approach is incorporated into a flipped-classroom concept, as well as classical teaching concepts, offering students practical experience in control engineering. In addition, the design of the pendulum is shown, using a Raspberry Pi as the target platform for Matlab Simulink. This pendulum can be used in the classroom to evaluate the controller design mentioned above. It is analysed if the use of the pendulum generates a deeper understanding of the learning contents.
KW  - Matlab
KW  - Engineering education
KW  - Online services
KW  - Software packages
KW  - Electronic learning
KW  - Control engineering
Y1  - 2024
U6  - https://doi.org/10.1109/EDUCON60312.2024.10578937
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  - 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  - GEN
A1  - Dieringer, Matthias A.
A1  - Renz, Wolfgang
A1  - Lindel, Tomasz Dawid
A1  - Seifert, Frank
A1  - Frauenrath, Tobias
A1  - Waiczies, Helmar
A1  - von Knobelsdorff-Brenkhoff, Florian
A1  - Santoro, Davide
A1  - Hoffmann, Werner
A1  - Ittermann, Bernd
A1  - Schulz-Menger, Jeanette
A1  - Niendorf, Thoralf
T1  - 4CH TX/RX Surface Coil for 7T: Design, Optimization and Application for Cardiac Function Imaging
T2  - 2010 ISMRM-ESMRMB joint annual meeting
N2  - Practical impediments of ultra high field cardiovascular MR (CVMR) can be catalogued in exacerbated magnetic field and radio frequency (RF) inhomogeneities, susceptibility and off-resonance effects, conductive and dielectric effects in tissue, and RF power deposition constraints, which all bear the potential to spoil the benefit of CVMR at 7T. Therefore, a four element cardiac transceive surface coil array was developed. Cardiac imaging provided clinically acceptable signal homogeneity with an excellent blood myocardium contrast. Subtle anatomic structures, such as pericardium, mitral and tricuspid valves and their apparatus, papillary muscles, and trabecles were accurately delineated.
Y1  - 2010
SN  - 1545-4428
N1  - ISMRM-ESMRMB joint annual meeting, 1 - 7 May 2010, Stockholm, Sweden
ER  - 
TY  - GEN
A1  - Frauenrath, Tobias
A1  - Becker, Meike
A1  - Hezel, Fabian
A1  - Krombach, Gabriele A.
A1  - Kremer, Ute
A1  - Schulz-Menger, Jeanette
A1  - Niendorf, Thoralf
T1  - Comparison of Left Function Assessment Using Phonocardiogram and Electrocardiogram Triggered 2D SSFP CINE MR Imaging at 1.5 T and 3.0 T
T2  - 2010 ISMRM-ESMRMB joint annual meeting
N2  - As high-field cardiac MRI (CMR) becomes more widespread the propensity of ECG to distortions and mistriggering increases and with it the motivation for a cardiac triggering alternative. Hence, this study explores the suitability of acoustic cardiac triggering (ACT) for left ventricular (LV) function assessment in healthy subjects at 1.5T and 3.0T.
Y1  - 2010
SN  - 1545-4428
N1  - ISMRM-ESMRMB joint annual meeting, 1 - 7 May 2010, Stockholm, Sweden
ER  - 
TY  - GEN
A1  - Hezel, Fabian
A1  - Frauenrath, Tobias
A1  - Renz, Wolfgang
A1  - Schulz-Menger, Jeanette
A1  - Niendorf, Thoralf
T1  - Feasibility of CINE Myocardial T2* Mapping Using Susceptibility Weighted Gradient-Echo Imaging at 7.0 T
T2  - 2010 ISMRM-ESMRMB joint annual meeting
N2  - This study is designed to demonstrate the promise of susceptibility weighted 2D CINE FLASH and T2* Mapping of the heart at 7T.
Y1  - 2010
SN  - 1545-4428
N1  - ISMRM-ESMRMB joint annual meeting, 1 - 7 May 2010, Stockholm, Sweden
ER  - 
TY  - GEN
A1  - Frauenrath, Tobias
A1  - Renz, Wolfgang
A1  - Rieger, Jan
A1  - Gömmel, Andreas
A1  - Butenweg, Christoph
A1  - Niendorf, Thoralf
T1  - High Spatial Resolution 3D MRI of the Larynx Using a Dedicated TX/RX Phased Array Coil at 7.0T
T2  - 2010 ISMRM-ESMRMB joint annual meeting
N2  - MRI holds great potential for elucidating laryngeal and vocal fold anatomy together with the assessment of physiological processes associated in human phonation. However, MRI of human phonation remains very challenging due to the small size of the targeted structures, interfering signal from fat, air between the vocal folds and surrounding muscles and physiological motion. These anatomical/physiological constraints translate into stringent technical requirements in balancing, scan time, image contrast, immunity to physiological motion, temporal resolution and spatial resolution. Motivated by these challenges and limitations this study is aiming at translating the sensitivity gain at ultra-high magnetic fields for enhanced high spatial resolution 3D imaging of the larynx and vocal tract. To approach this goal a dedicated two channel TX/RX larynx coil is being proposed.
Y1  - 2010
SN  - 1545-4428
N1  - ISMRM-ESMRMB joint annual meeting, 1 - 7 May 2010, Stockholm, Sweden
ER  - 
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  - Aliazizi, Fereshteh
A1  - Özsoylu, Dua
A1  - Bakhshi Sichani, Soroush
A1  - Khorshid, Mehran
A1  - Glorieux, Christ
A1  - Robbens, Johan
A1  - Schöning, Michael Josef
A1  - Wagner, Patrick
T1  - Development and Calibration of a Microfluidic, Chip-Based Sensor System for Monitoring the Physical Properties of Water Samples in Aquacultures
JF  - Micromachines
N2  - In this work, we present a compact, bifunctional chip-based sensor setup that measures the temperature and electrical conductivity of water samples, including specimens from rivers and channels, aquaculture, and the Atlantic Ocean. For conductivity measurements, we utilize the impedance amplitude recorded via interdigitated electrode structures at a single triggering frequency. The results are well in line with data obtained using a calibrated reference instrument. The new setup holds for conductivity values spanning almost two orders of magnitude (river versus ocean water) without the need for equivalent circuit modelling. Temperature measurements were performed in four-point geometry with an on-chip platinum RTD (resistance temperature detector) in the temperature range between 2 °C and 40 °C, showing no hysteresis effects between warming and cooling cycles. Although the meander was not shielded against the liquid, the temperature calibration provided equivalent results to low conductive Milli-Q and highly conductive ocean water. The sensor is therefore suitable for inline and online monitoring purposes in recirculating aquaculture systems.
KW  - chip-based sensor setup
KW  - aquaculture
KW  - microfluidics
KW  - impedance spectroscopy
KW  - thermometry
KW  - electrical conductivity of liquids
Y1  - 2024
U6  - https://doi.org/10.3390/mi15060755
SN  - 2072-666X
N1  - This article belongs to the Special Issue "Multisensor Arrays"
N1  - Corresponding author: Michael J. Schöning
VL  - 15
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - GEN
A1  - Roth, J.
A1  - Tippkötter, Nils
T1  - New Approach for Enzymatic Hydrolysis of Lignocellulose with Selective Diffusion Separation of the Monosaccharide Products
T2  - Chemie Ingenieur Technik
N2  - Enzymatic hydrolysis of lignocellulosic material plays an important role in the classical biorefinery approach. Apart from the pretreatment of the raw material, hydrolysis is the basis for the conversion of the cellulose and hemicellulose fraction into fermentable sugars. After hydrolysis, usually a solid-liquid separation takes place, in order to separate the residual plant material from the sugar-rich fraction, which can be subsequently used in a fermentation step. In order to factor out the separation step, the usage of in alginate immobilized crude cellulose fiber beads (CFBs) were evaluated. Pretreated cellulose fibers are incorporated in an alginate matrix together with the relevant enzymes. In doing so, sugars diffuse trough the alginate matrix, allowing a simplified delivery into the surrounding fluid. This again reduces product inhibition of the glucose on the enzyme catalysts. By means of standardized bead production the hydrolysis in lab scale was possible. First results show that liberation of glucose and xylose is possible, allowing a maximum total sugar yield of 75 %.
Y1  - 2016
U6  - https://doi.org/10.1002/cite.201650301
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung 2016 und 32. DECHEMA-Jahrestagung der Biotechnologen 2016, 12. - 15. September 2016, Eurogress Aachen
VL  - 88
IS  - 9
SP  - 1237
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Tippkötter, Nils
A1  - Ulber, Roland
T1  - Rezension zu: Encyclopedia of Industrial Biotechnology, Vol. 1–7. By MC Flickinger.
JF  - Chemie Ingenieur Technik
Y1  - 2012
U6  - https://doi.org/10.1002/cite.201290052
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
VL  - 6
IS  - 84
SP  - 936
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Duwe, A.
A1  - Schlegel, C.
A1  - Tippkötter, Nils
A1  - Ulber, Roland
T1  - Sequentielle Extraktion von Cellulose zur effizienten Nutzung der Stoffströme in der Holzbioraffinerie
T2  - Chemie Ingenieur Technik
N2  - In der Reihe der nachwachsenden Rohstoffe besitzt Holz als erneuerbare und umweltfreundliche Ressource ein großes Potenzial. Über 11 Mio. ha Holz, das laut der Fachagentur für nachwachsende Rohstoffe (FNR) auch für industrielle Zwecke genutzt werden kann, wuchsen im Jahr 2013 allein auf bundesdeutscher Fläche. 56,8 Mio. m³ jährlicher Holzeinschlag in den letzten zehn Jahren wurde zu knapp der Hälfte stofflich und der Rest energetisch verwertet. Im Rahmen dieser Arbeit konnte auf der Basis vom Holz der Buche, die nach Fichte und Kiefer die dritthäufigste Baumart in Deutschland ist und 15% der deutschen Waldfläche ausmacht, die Fraktionierung der polymeren Hauptbestandteile mit niedrigem energetischen Einsatz erreicht werden. Hierbei werden in einem nachgeschalteten Extraktionsprozess die beiden Komponenten Hemicellulose und Lignin in flüssiger Form von der finalen festen Cellulosefraktion abgetrennt. Die Extraktion der Hemicellulose erfolgt durch eine Liquid Hot Water (LHW)-Behandlung. Untersucht wird der katalytische Zusatz anorganischer Säuren wie H₃PO₄ und H₂SO₄. Im Hinblick auf die weitere Verwertung von Lignin zu aromatischen Synthesebausteinen kommt die Organosolv-Extraktion mit einem Ethanol/Wasser-Gemisch zum Einsatz. Von Vorteil ist die weitere Verwendung beider Stoffströme ohne Fällungsschritt und nachteiliger Verdünnung der Hemicellulose.
Y1  - 2014
U6  - https://doi.org/10.1002/cite.201450308
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung 2014 und 31. DECHEMA-Jahrestagung der Biotechnologen, 30. September - 2. Oktober 2014, Eurogress Aachen
VL  - 86
IS  - 9
SP  - 1400
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Möhring, S.
A1  - Wulfhorst, H.
A1  - Capitain, C.
A1  - Roth, J.
A1  - Tippkötter, Nils
T1  - Fractioning of lignocellulosic biomass: Scale-down and automation of thermal pretreatment for parameter optimization
T2  - Chemie Ingenieur Technik
N2  - In order to efficiently convert lignocellulose, it is often necessary to conduct a pretreatment. The biomass considered in this study typically comprises of agricultural and horticultural residues, as well as beechwood. A very environmentally friendly method, namely, fungal pretreatment using white-rot fungi, leads to an enhanced enzymatic hydrolysis. In contrast to other processes presented, the energy input is extremely low. However, the fungal growth on the lignocellulosic substrates takes several weeks at least in order to be effective. Thus, the reduction of chemicals and energy for thermal processing is a target of our current research. Liquid hot water (LHW) and solvent-based pretreatment (OrganoSolv) require more complex equipment, as they depend on high temperatures (160 – 180 °C) and enhanced pressure (up to 20 bar). However, they prove to be promising processes in regard to the fractioning of lignocellulose. For optimal lignin recovery the parameters differ from those established in cellulose extraction. A novel screening system scaled down to a reaction volume of 100 mL has been developed and successfully tested for this purpose.
Y1  - 2016
U6  - https://doi.org/10.1002/cite.201650288
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung und 32. DECHEMA-Jahrestagung der Biotechnologen 2016, 12. - 15. September 2016, Eurogress Aachen
VL  - 88
IS  - 9
SP  - 1229
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Ross-Jones, J.
A1  - Teumer, T.
A1  - Capitain, C.
A1  - Tippkötter, Nils
A1  - Krause, M. J.
A1  - Methner, F.-J.
A1  - Rädle, M.
T1  - Analytical methods for in-line characterization of beer haze
T2  - Trends in Brewing
N2  - In most beers, producers strive to minimize haze to maximize visual appeal. To detect the formation of particulates, a measurement system for sub-micron particles is required. Beer haze is naturally occurring, composed of protein or polyphenol particles; in their early stage of growth their size is smaller than 2 µm. Microscopy analysis is time and resource intensive; alternatively, backscattering is an inexpensive option for detecting particle sizes of interest.
Y1  - 2018
N1  - Trends in Brewing, April 8 –12, 2018, Ghent, Belgium
ER  - 
TY  - CHAP
A1  - Engel, Mareike
A1  - Thieringer, Julia
A1  - Tippkötter, Nils
T1  - Linking bioprocess engineering and electrochemistry for sustainable biofuel production
T2  - Young Researchers Symposium, YRS 2016. Proceedings
N2  - Electromicrobial engineering is an emerging, highly interdisciplinary research area linking bioprocesses with electrochemistry. In this work, microbial electrosynthesis (MES) of biobutanol is carried out during acetone-butanol-ethanol (ABE) fermentations with Clostridium acetobutylicum. A constant electric potential of −600mV (vs. Ag/AgCl) with simultaneous addition of the soluble redox mediator neutral red is used in order to study the electron transfer between the working electrode and the bacterial cells. The results show an earlier initiation of solvent production for all fermentations with applied potential compared to the conventional ABE fermentation. The f inal butanol concentration can be more than doubled by the application of a negative potential combined with addition of neutral red. Moreover a higher biofilm formation on the working electrode compared to control cultivations has been observed. In contrast to previous studies, our results also indicate that direct electron transfer (DET) might be possible with C. acetobutylicum. The presented results make microbial butanol production economically attractive and therefore support the development of sustainable production processes in the chemical industry aspired by the “Centre for resource-efficient chemistry and raw material change” as well as the the project “NanoKat” working on nanostructured catalysts in Kaiserslautern.
Y1  - 2016
N1  - Young Researchers Symposium, YRS 2016, 14th - 15th April 2016, Fraunhofer-Zentrum Kaiserslautern
SP  - 49
EP  - 53
PB  - Fraunhofer Verlag
CY  - Karlsruhe
ER  - 
TY  - GEN
A1  - Tippkötter, Nils
A1  - Ulber, Roland
T1  - Eine magnetische horizontale Wirbelschicht für die Durchmischung und Rückhaltung von magnetisierbaren Mikropartikeln im Durchfluss
T2  - Chemie Ingenieur Technik
N2  - Magnetisierbare Partikel als Träger von Katalysatoren können durch Anlegen eines magnetisches Feldes einfach und schnell abgetrennt werden. Die Wiedergewinnung von wertvollen Enzymen unter geringem Energie- und Materialeinsatz der magnetischen Abtrennung eröffnet einen Wettbewerbsvorteil für Produktionsprozesse. Die Abtrennung von magnetisierbaren Partikeln vom Überstand wird üblicherweise entweder durch Anlegen eines äußeren Magnetfelds und der resultierenden Ablagerung der Partikel an den Reaktorwänden oder durch Hochgradientenmagnetseparation (HGMS)durchgeführt. Beide Verfahren resultieren meist in der Bildung eines Filterkuchens aus Magnetpartikeln und den Feststoffen des Reaktionsmediums. Das magnetische horizontale Wirbelbett ermöglicht simultan eine kontinuierliche Reaktionsführung und die Rückhaltung der Partikel im Durchfluss. Die Partikelsuspension fließt durch einen Rohrreaktor, der in einem Magnetfeld mit wechselnden Feldgradienten eingebracht ist. Die Änderung des Magnetfeldgradienten erfolgt entgegen der Strömungsrichtung der Reaktionslösung. Durch alternierende Feldmaxima an den beiden Seiten des Reaktors werden die magnetisierbaren Partikel zu dessen Wänden gezogen. Bei Umkehrung des Feldes wandern die Partikel an die gegenüberliegende Reaktorwand. Durch Wahl einer geeigneten Wechselfrequenz kann eine kontinuierliche Durchmischung und Rückhaltung der Mikropartikel im durchströmten Rohr erreicht werden. Somit können Immobilisierungsreaktionen und Biotransformationen mit den Partikelsystemen im Durchfluss durchgeführt werden.
Y1  - 2009
U6  - https://doi.org/10.1002/cite.200950076
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet‐Jahrestagung 2009 und 27. DECHEMA-Jahrestagung der Biotechnologen, 8.- 10. September 2009, Mannheim
VL  - 81
IS  - 8
SP  - 1168
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Frauenrath, Tobias
A1  - Niendorf, Thoralf
A1  - Kob, Malte
T1  - Acoustic method for synchronization of Magnetic Resonance Imaging (MRI)
JF  - Acta Acustica
N2  - Magnetic Resonance Imaging (MRI) of moving organs requires synchronization with physiological motion or flow, which dictate the viable window for data acquisition. To meet this challenge, this study proposes an acoustic gating device (ACG) that employs acquisition and processing of acoustic signals for synchronization while providing MRI compatibility, immunity to interferences with electro-magnetic and acoustic fields and suitability for MRI at high magnetic field strengths. The applicability and robustness of the acoustic gating approach is examined in a pilot study, where it substitutes conventional ECG-gating for cardiovascular MR. The merits and limitations of the ACG approach are discussed. Implications for MR imaging in the presence of physiological motion are considered including synchronization with other structure- or motion borne sounds.
Y1  - 2008
U6  - https://doi.org/10.3813/AAA.918017
SN  - 1861-9959
VL  - 94
IS  - 1
SP  - 148
EP  - 155
PB  - Hirzel
CY  - Stuttgart
ER  -