@article{AbbasBalcBremenetal.2022, author = {Abbas, Karim and Balc, Nicolae and Bremen, Sebastian and Skupin, Marco}, title = {Crystallization and aging behavior of polyetheretherketone PEEK within rapid tooling and rubber molding}, series = {Journal of Manufacturing and Materials Processing}, volume = {6}, journal = {Journal of Manufacturing and Materials Processing}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {2504-4494}, doi = {10.3390/jmmp6050093}, pages = {1 -- 12}, year = {2022}, abstract = {In times of short product life cycles, additive manufacturing and rapid tooling are important methods to make tool development and manufacturing more efficient. High-performance polymers are the key to mold production for prototypes and small series. However, the high temperatures during vulcanization injection molding cause thermal aging and can impair service life. The extent to which the thermal stress over the entire process chain stresses the material and whether it leads to irreversible material aging is evaluated. To this end, a mold made of PEEK is fabricated using fused filament fabrication and examined for its potential application. The mold is heated to 200 ◦C, filled with rubber, and cured. A differential scanning calorimetry analysis of each process step illustrates the crystallization behavior and first indicates the material resistance. It shows distinct cold crystallization regions at a build chamber temperature of 90 ◦C. At an ambient temperature above Tg, crystallization of 30\% is achieved, and cold crystallization no longer occurs. Additional tensile tests show a decrease in tensile strength after ten days of thermal aging. The steady decrease in recrystallization temperature indicates degradation of the additives. However, the tensile tests reveal steady embrittlement of the material due to increasing crosslinking.}, language = {en} } @article{AbbasHedwigBalcetal.2023, author = {Abbas, Karim and Hedwig, Lukas and Balc, Nicolae and Bremen, Sebastian}, title = {Advanced FFF of PEEK: Infill strategies and material characteristics for rapid tooling}, series = {Polymers}, volume = {2023}, journal = {Polymers}, number = {15}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/polym15214293}, pages = {Artikel 4293}, year = {2023}, abstract = {Traditional vulcanization mold manufacturing is complex, costly, and under pressure due to shorter product lifecycles and diverse variations. Additive manufacturing using Fused Filament Fabrication and high-performance polymers like PEEK offer a promising future in this industry. This study assesses the compressive strength of various infill structures (honeycomb, grid, triangle, cubic, and gyroid) when considering two distinct build directions (Z, XY) to enhance PEEK's economic and resource efficiency in rapid tooling. A comparison with PETG samples shows the behavior of the infill strategies. Additionally, a proof of concept illustrates the application of a PEEK mold in vulcanization. A peak compressive strength of 135.6 MPa was attained in specimens that were 100\% solid and subjected to thermal post-treatment. This corresponds to a 20\% strength improvement in the Z direction. In terms of time and mechanical properties, the anisotropic grid and isotropic cubic infill have emerged for use in rapid tooling. Furthermore, the study highlights that reducing the layer thickness from 0.15 mm to 0.1 mm can result in a 15\% strength increase. The study unveils the successful utilization of a room-temperature FFF-printed PEEK mold in vulcanization injection molding. The parameters and infill strategies identified in this research enable the resource-efficient FFF printing of PEEK without compromising its strength properties. Using PEEK in rapid tooling allows a cost reduction of up to 70\% in tool production.}, language = {en} } @article{AbdelLatifPeekenBenner1985, author = {Abdel-Latif, Lotfie Ahmed and Peeken, Heinz and Benner, Joachim}, title = {Thermohydrodynamic analysis of thrust-bearing with circular pads running on bubbly oil (BTHD-theory)}, series = {Journal of tribology}, volume = {107}, journal = {Journal of tribology}, number = {4}, isbn = {0742-4787}, issn = {1528-8897}, pages = {527 -- 537}, year = {1985}, language = {en} } @article{AbdelLatifPeekenBenner1985, author = {Abdel-Latif, Lotfie Ahmed and Peeken, Heinz and Benner, Joachim}, title = {Термогидродинамический расчет упорных подшипников с круговыми подушками на масляной пленке, содержащей пузырьки газа}, series = {Проблемы трения и смазки}, volume = {107}, journal = {Проблемы трения и смазки}, number = {4}, pages = {94 -- 102}, year = {1985}, language = {ru} } @article{AbelKahmannMellonetal.2020, author = {Abel, Alexander and Kahmann, Stephanie Lucina and Mellon, Stephen and Staat, Manfred and Jung, Alexander}, title = {An open-source tool for the validation of finite element models using three-dimensional full-field measurements}, series = {Medical Engineering \& Physics}, volume = {77}, journal = {Medical Engineering \& Physics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1350-4533}, doi = {10.1016/j.medengphy.2019.10.015}, pages = {125 -- 129}, year = {2020}, abstract = {Three-dimensional (3D) full-field measurements provide a comprehensive and accurate validation of finite element (FE) models. For the validation, the result of the model and measurements are compared based on two respective point-sets and this requires the point-sets to be registered in one coordinate system. Point-set registration is a non-convex optimization problem that has widely been solved by the ordinary iterative closest point algorithm. However, this approach necessitates a good initialization without which it easily returns a local optimum, i.e. an erroneous registration. The globally optimal iterative closest point (Go-ICP) algorithm has overcome this drawback and forms the basis for the presented open-source tool that can be used for the validation of FE models using 3D full-field measurements. The capability of the tool is demonstrated using an application example from the field of biomechanics. Methodological problems that arise in real-world data and the respective implemented solution approaches are discussed.}, language = {en} } @article{AboulnagaZouSelmeretal.2018, author = {Aboulnaga, E. A. and Zou, H. and Selmer, Thorsten and Xian, M.}, title = {Development of a plasmid-based, tunable, tolC-derived expression system for application in Cupriavidus necator H16}, series = {Journal of Biotechnology}, volume = {274}, journal = {Journal of Biotechnology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2018.03.007}, pages = {15 -- 27}, year = {2018}, abstract = {Cupriavidus necator H16 gains increasing attention in microbial research and biotechnological application due to its diverse metabolic features. Here we present a tightly controlled gene expression system for C. necator including the pBBR1-vector that contains hybrid promoters originating from C. necator native tolC-promoter in combination with a synthetic tetO-operator. The expression of the reporter gene from these plasmids relies on the addition of the exogenous inducer doxycycline (dc). The novel expression system offers a combination of advantageous features as; (i) high and dose-dependent recombinant protein production, (ii) tight control with a high dynamic range (On/Off ratio), which makes it applicable for harmful pathways or for toxic protein production, (iii) comparable cheap inducer (doxycycline, dc), (iv) effective at low inducer concentration, that makes it useful for large scale application, (v) rapid, diffusion controlled induction, and (vi) the inducer does not interfere within the cell metabolism. As applications of the expression system in C. necator H16, the growth ability on glycerol was enhanced by constitutively expressing the E. coli glpk gene-encoding for glycerol kinase. Likewise, we used the system to overcome the expression toxicity of mevalonate pathway in C. necator H16. With this system, the mevalonate-genes were successfully introduced in the host and the recombinant strains could produce about 200 mg/l mevalonate.}, language = {en} } @article{AboulnagaPinkenburgSchiffelsetal.2013, author = {Aboulnaga, E. H. and Pinkenburg, O. and Schiffels, Johannes and El-Refai, A. and Buckel, W. and Selmer, Thorsten}, title = {Butyrate production in Escherichia coli: Exploitation of an oxygen tolerant bifurcating butyryl-CoA dehydrogenase/electron transferring flavoprotein complex from Clostridium difficile}, series = {Journal of bacteriology. June 14, 2013}, journal = {Journal of bacteriology. June 14, 2013}, issn = {1098-5530 (E-Journal) ; 0021-9193 (Print)}, pages = {Epub ahead of print}, year = {2013}, language = {de} } @article{AbouzarIngebrandtPoghossianetal.2009, author = {Abouzar, Maryam H. and Ingebrandt, S. and Poghossian, Arshak and Zhang, Y. and Moritz, W. and Sch{\"o}ning, Michael Josef}, title = {Field-effect nanoplate capacitive pH sensor based on SOI structure}, series = {Semiconductor micro- and nanoelectronics : Proceedings of the Seventh International Conference , Tsakhcadzor, Armenia July 3-5 2009}, journal = {Semiconductor micro- and nanoelectronics : Proceedings of the Seventh International Conference , Tsakhcadzor, Armenia July 3-5 2009}, pages = {55 -- 58}, year = {2009}, language = {en} } @article{AbouzarIngebrandtPoghossianetal.2009, author = {Abouzar, Maryam H. and Ingebrandt, S. and Poghossian, Arshak and Zhang, Y. and Vu, X. T. and Moritz, W. and Sch{\"o}ning, Michael Josef}, title = {Nanoplate field-effect capacitive (bio-)chemical sensor array based on SOI structure}, series = {Procedia Chemistry. 1 (2009), H. 1}, journal = {Procedia Chemistry. 1 (2009), H. 1}, isbn = {1876-6196}, pages = {670 -- 673}, year = {2009}, language = {en} } @article{AbouzarPedrazaSchoeningetal.2010, author = {Abouzar, Maryam H. and Pedraza, A. M. and Sch{\"o}ning, Michael Josef and Poghossian, Arshak}, title = {Label-free DNA hybridization and denaturation detection by means of field-effect nanoplate SOI capacitors functionalized with gold nanoparticles}, series = {Procedia Engineering. 5 (2010)}, journal = {Procedia Engineering. 5 (2010)}, isbn = {1877-7058}, pages = {918 -- 921}, year = {2010}, language = {en} } @article{AbouzarPoghossianCherstvyetal.2012, author = {Abouzar, Maryam H. and Poghossian, Arshak and Cherstvy, Andrey G. and Pedraza, Angela M. and Ingebrandt, Sven and Sch{\"o}ning, Michael Josef}, title = {Label-free electrical detection of DNA by means of field-effect nanoplate capacitors: Experiments and modeling}, series = {Physica Status Solidi (a)}, volume = {209}, journal = {Physica Status Solidi (a)}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201100710}, pages = {925 -- 934}, year = {2012}, abstract = {Label-free electrical detection of consecutive deoxyribonucleic acid (DNA) hybridization/denaturation by means of an array of individually addressable field-effect-based nanoplate silicon-on-insulator (SOI) capacitors modified with gold nanoparticles (Au-NP) is investigated. The proposed device detects charge changes on Au-NP/DNA hybrids induced by the hybridization or denaturation event. DNA hybridization was performed in a high ionic-strength solution to provide a high hybridization efficiency. On the other hand, to reduce the screening of the DNA charge by counter ions and to achieve a high sensitivity, the sensor signal induced by the hybridization and denaturation events was measured in a low ionic-strength solution. High sensor signals of about 120, 90, and 80 mV were registered after the DNA hybridization, denaturation, and re-hybridization events, respectively. Fluorescence microscopy has been applied as reference method to verify the DNA immobilization, hybridization, and denaturation processes. An electrostatic charge-plane model for potential changes at the gate surface of a nanoplate field-effect sensor induced by the DNA hybridization has been developed taking into account both the Debye length and the distance of the DNA charge from the gate surface.}, language = {en} } @article{AbouzarPoghossianPedrazaetal.2011, author = {Abouzar, Maryam H. and Poghossian, Arshak and Pedraza, A. M. and Gandhi, D. and Ingebrandt, S. and Moritz, W. and Sch{\"o}ning, Michael Josef}, title = {An array of field-effect nanoplate SOI capacitors for (bio-)chemical sensing}, series = {Biosensors and Bioelectronics. 26 (2011), H. 6}, journal = {Biosensors and Bioelectronics. 26 (2011), H. 6}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0956-5663}, pages = {3023 -- 3028}, year = {2011}, language = {en} } @article{AbouzarPoghossianRazavietal.2009, author = {Abouzar, Maryam H. and Poghossian, Arshak and Razavi, A. and Williams, O. A. and Bijnens, N. and Wagner, P. and Sch{\"o}ning, Michael Josef}, title = {Characterisation of capacitive field-effect sensors with a nanocrystalline-diamond film as transducer material for multi-parameter sensing}, series = {Biosensors and Bioelectronics. 24 (2009), H. 5}, journal = {Biosensors and Bioelectronics. 24 (2009), H. 5}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0956-5663}, pages = {1298 -- 1304}, year = {2009}, language = {en} } @article{AbouzarPoghossianRazavietal.2008, author = {Abouzar, Maryam H. and Poghossian, Arshak and Razavi, Arash and Besmehn, Astrid and Bijnens, Nathalie and Williams, Oliver A. and Haenen, Ken and Wagner, Patrick and Sch{\"o}ning, Michael Josef}, title = {Penicillin detection with nanocrystalline-diamond field-effect sensor}, series = {physica status solidi (a). 205 (2008), H. 9}, journal = {physica status solidi (a). 205 (2008), H. 9}, isbn = {1862-6319}, pages = {2141 -- 2145}, year = {2008}, language = {en} } @article{AbouzarPoghossianSiqueiraetal.2010, author = {Abouzar, Maryam H. and Poghossian, Arshak and Siqueira, Jos{\´e} R. Jr. and Oliveira, Osvaldo N. Jr. and Moritz, Werner and Sch{\"o}ning, Michael Josef}, title = {Capacitive electrolyte-insulator-semiconductor structures functionalised with a polyelectrolyte/enzyme multilayer: New strategy for enhanced field-effect biosensing}, series = {Physica Status Solidi (A). 207 (2010), H. 4}, journal = {Physica Status Solidi (A). 207 (2010), H. 4}, isbn = {1862-6300}, pages = {884 -- 890}, year = {2010}, language = {en} } @article{AbouzarSchoeningPoghossianetal.2008, author = {Abouzar, Maryam H. and Sch{\"o}ning, Michael Josef and Poghossian, Arshak and Christiaens, P. and Williams, O. A. and Wagner, P. and Haenen, K.}, title = {Feldeffektsensor auf nanokristalliner Diamantbasis}, series = {Sensoren und Messsysteme 2008 : 14. Fachtagung Ludwigsburg, 11. und 12. M{\"a}rz 2008 / VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik}, journal = {Sensoren und Messsysteme 2008 : 14. Fachtagung Ludwigsburg, 11. und 12. M{\"a}rz 2008 / VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik}, publisher = {VDI-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-18-092011-5}, pages = {549 -- 558}, year = {2008}, language = {de} } @article{AbouzarWernerSchoeningetal.2011, author = {Abouzar, Maryam H. and Werner, Moritz and Sch{\"o}ning, Michael Josef and Poghossian, Arshak}, title = {Capacitance-voltage and impedance-spectroscopy characteristics of nanoplate EISOI capacitors}, series = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, journal = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, publisher = {Wiley-VCH}, address = {Berlin}, isbn = {1862-6319}, pages = {1327 -- 1332}, year = {2011}, language = {en} } @article{AbulnagaPinkenburgSchiffelsetal.2013, author = {Abulnaga, El-Hussiny and Pinkenburg, Olaf and Schiffels, Johannes and E-Refai, Ahmed and Buckel, Wolfgang and Selmer, Thorsten}, title = {Effect of an Oxygen-Tolerant Bifurcating Butyryl Coenzyme A Dehydrogenase/Electron-Transferring Flavoprotein Complex from Clostridium difficile on Butyrate Production in Escherichia coli}, series = {Journal of bacteriology}, volume = {195}, journal = {Journal of bacteriology}, number = {16}, issn = {1098-5530 [E-Journal]}, pages = {3704 -- 3713}, year = {2013}, language = {en} } @article{AchtsnichtNeuendorfFassbenderetal.2019, author = {Achtsnicht, Stefan and Neuendorf, Christian and Faßbender, Tobias and N{\"o}lke, Greta and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim and Schr{\"o}per, Florian}, title = {Sensitive and rapid detection of cholera toxin subunit B using magnetic frequency mixing detection}, series = {Plos One}, volume = {14}, journal = {Plos One}, number = {7}, publisher = {Plos}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0219356}, pages = {e0219356}, year = {2019}, abstract = {Cholera is a life-threatening disease caused by the cholera toxin (CT) as produced by some Vibrio cholerae serogroups. In this research we present a method which directly detects the toxin's B subunit (CTB) in drinking water. For this purpose we performed a magnetic sandwich immunoassay inside a 3D immunofiltration column. We used two different commercially available antibodies to capture CTB and for binding to superparamagnetic beads. ELISA experiments were performed to select the antibody combination. The beads act as labels for the magnetic frequency mixing detection technique. We show that the limit of detection depends on the type of magnetic beads. A nonlinear Hill curve was fitted to the calibration measurements by means of a custom-written python software. We achieved a sensitive and rapid detection of CTB within a broad concentration range from 0.2 ng/ml to more than 700 ng/ml.}, language = {en} } @article{AchtsnichtPourshahidiOffenhaeusseretal.2019, author = {Achtsnicht, Stefan and Pourshahidi, Ali Mohammad and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim}, title = {Multiplex detection of different magnetic beads using frequency scanning in magnetic frequency mixing technique}, series = {Sensors}, volume = {19}, journal = {Sensors}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s19112599}, pages = {13 Seiten}, year = {2019}, abstract = {In modern bioanalytical methods, it is often desired to detect several targets in one sample within one measurement. Immunological methods including those that use superparamagnetic beads are an important group of techniques for these applications. The goal of this work is to investigate the feasibility of simultaneously detecting different superparamagnetic beads acting as markers using the magnetic frequency mixing technique. The frequency of the magnetic excitation field is scanned while the lower driving frequency is kept constant. Due to the particles' nonlinear magnetization, mixing frequencies are generated. To record their amplitude and phase information, a direct digitization of the pickup-coil's signal with subsequent Fast Fourier Transformation is performed. By synchronizing both magnetic beads using frequency scanning in magnetic frequency mixing technique magnetic fields, a stable phase information is gained. In this research, it is shown that the amplitude of the dominant mixing component is proportional to the amount of superparamagnetic beads inside a sample. Additionally, it is shown that the phase does not show this behaviour. Excitation frequency scans of different bead types were performed, showing different phases, without correlation to their diverse amplitudes. Two commercially available beads were selected and a determination of their amount in a mixture is performed as a demonstration for multiplex measurements.}, language = {en} }