Refine
Year of publication
- 2024 (47) (remove)
Institute
- Fachbereich Medizintechnik und Technomathematik (21)
- IfB - Institut für Bioengineering (10)
- Fachbereich Elektrotechnik und Informationstechnik (8)
- Fachbereich Luft- und Raumfahrttechnik (5)
- INB - Institut für Nano- und Biotechnologien (5)
- Fachbereich Wirtschaftswissenschaften (4)
- Fachbereich Chemie und Biotechnologie (3)
- ECSM European Center for Sustainable Mobility (2)
- Fachbereich Energietechnik (2)
- Arbeitsstelle fuer Hochschuldidaktik und Studienberatung (1)
Has Fulltext
- no (47) (remove)
Language
- English (47) (remove)
Document Type
- Article (27)
- Conference Proceeding (12)
- Book (3)
- Part of a Book (3)
- Preprint (2)
Keywords
- Engineering education (2)
- Hot S-parameter (2)
- 1P hub loads (1)
- 3-D printing (1)
- 316L (1)
- ABE (1)
- Accuracy (1)
- Acid crash (1)
- Active humidity control (1)
- Additive manufacturing (1)
- Aeroelasticity (1)
- Ageing (1)
- Agent-based modeling (1)
- Analytical models (1)
- Anatomy (1)
- Boundary integral equations, (1)
- Butanol (1)
- C. acetobutylicum (1)
- Capacitive model (1)
- Circuit simulation (1)
- Coal (1)
- Collagen fibrils (1)
- Comparative simulation (1)
- Complex-valued eigenvalues (1)
- Connective tissues (1)
- Constitutive model (1)
- Control engineering (1)
- DAC (1)
- DC machines (1)
- Damage mechanics theory (1)
- Data analysis (1)
- Data visualization (1)
- Database (1)
- Discontinuous fractures (1)
- Dynamic modeling (1)
- ESATAN-TMS (1)
- Eigenvalue trajectories (1)
- Electrochemical impedance spectroscopy (1)
- Electronic learning (1)
- Energy dispatch (1)
- Energy market (1)
- Enzyme coverage (1)
- Exponential Euler scheme, (1)
- Extracellular matrix (ECM) (1)
- Fault detection (1)
- Field-effect biosensor (1)
- Flutter (1)
- Focusing (1)
- Fuel cell (1)
- Furnace (1)
- Fusion (1)
- Germany (1)
- H2 (1)
- Health management system (1)
- Hydrogenotrophic methanogens (1)
- Impedance analysis (1)
- Instruments (1)
- Interior transmission problem (1)
- LPBF (1)
- LQR (1)
- Li7La3Zr2O12 (1)
- LiGaO2 (1)
- Low voltage (1)
- Lunar Surface (1)
- MOS (1)
- MPC (1)
- Manifolds (1)
- Matlab (1)
- Measurement (1)
- Mechanical stability (1)
- Metabolic shift (1)
- Methane (1)
- Methanogenesis (1)
- Mode converter (1)
- Modeling (1)
- Monitoring (1)
- Multianalyte detection (1)
- Muscle (1)
- Musculoskeletal system (1)
- Non-model-based Evaluation (1)
- Non-parallel fissures (1)
- Nonlinear eigenvalue problems (1)
- Online diagnostic (1)
- Online services (1)
- Open Data (1)
- Open source (1)
- P2G (1)
- PEM fuel cell (1)
- PPO (1)
- Parabolic SPDEs (1)
- Penicillin (1)
- Physiology (1)
- Plasma (1)
- Plasma diagnostics (1)
- Power dissipation (1)
- Pre-culture (1)
- Propeller whirl flutter (1)
- Raman spectroscopy (1)
- Refining (1)
- Reinforcement Learning (1)
- Relative air humidity (1)
- Renewable energy sources (1)
- Rotatory Inverted Pendulum (1)
- SLM (1)
- Simulation (1)
- Software packages (1)
- Synchronous machines (1)
- Tapered ends (1)
- Thermal Model (1)
- Thermal analysis (1)
- Thermal conductivity (1)
- Throughput (1)
- Time-series (1)
- Training (1)
- Uniaxial compression test (1)
- Unsteady aerodynamics (1)
- Wellenausbreitung (1)
- antennas (1)
- aquaculture (1)
- artificial olfactory image (1)
- biodegradable polymers (1)
- biomethane (1)
- bubble column (1)
- carbon dioxide removal (1)
- catalytic metal (1)
- chip-based sensor setup (1)
- climate neutrality (1)
- coupled Néel–Brownian relaxation dynamics (1)
- direct air capture (1)
- economics (1)
- electrical circuits (1)
- electrical conductivity of liquids (1)
- electrical engineering (1)
- electronic nose (1)
- field simulation (1)
- field-effect structure (1)
- frequency mixing magnetic detection (1)
- ga-doping (1)
- garnet solid electrolyte (1)
- gas sensor (1)
- glycine (1)
- high-frequency technology (1)
- hydrogels (1)
- hydrogen peroxide (1)
- impedance spectroscopy (1)
- key performance indicators (1)
- light-addressing technologies (1)
- magnetic biosensing (1)
- magnetic nanoparticles (1)
- magnetic relaxation (1)
- metal-oxide-semiconductor structure (1)
- methanation (1)
- microfluidics (1)
- micromagnetic simulation (1)
- micronutrients (1)
- microwave technology (1)
- negative emissions (1)
- optical spore trapping (1)
- plasma technology (1)
- plug flow reactor (1)
- polyaspartic acid (1)
- rollout (1)
- scanned light pulse technique (1)
- solid-state battery (1)
- sterilization conditions (1)
- superabsorbent polymers (1)
- swelling properties (1)
- temperature (1)
- thermometry (1)
- visualization (1)
- wave propagation (1)
This paper investigates the interior transmission problem for homogeneous media via eigenvalue trajectories parameterized by the magnitude of the refractive index. In the case that the scatterer is the unit disk, we prove that there is a one-to-one correspondence between complex-valued interior transmission eigenvalue trajectories and Dirichlet eigenvalues of the Laplacian which turn out to be exactly the trajectorial limit points as the refractive index tends to infinity. For general simply-connected scatterers in two or three dimensions, a corresponding relation is still open, but further theoretical results and numerical studies indicate a similar connection.
New insights into the influence of pre-culture on robust solvent production of C. acetobutylicum
(2024)
Clostridia are known for their solvent production, especially the production of butanol. Concerning the projected depletion of fossil fuels, this is of great interest. The cultivation of clostridia is known to be challenging, and it is difficult to achieve reproducible results and robust processes. However, existing publications usually concentrate on the cultivation conditions of the main culture. In this paper, the influence of cryo-conservation and pre-culture on growth and solvent production in the resulting main cultivation are examined. A protocol was developed that leads to reproducible cultivations of Clostridium acetobutylicum. Detailed investigation of the cell conservation in cryo-cultures ensured reliable cell growth in the pre-culture. Moreover, a reason for the acid crash in the main culture was found, based on the cultivation conditions of the pre-culture. The critical parameter to avoid the acid crash and accomplish the shift to the solventogenesis of clostridia is the metabolic phase in which the cells of the pre-culture were at the time of inoculation of the main culture; this depends on the cultivation time of the pre-culture. Using cells from the exponential growth phase to inoculate the main culture leads to an acid crash. To achieve the solventogenic phase with butanol production, the inoculum should consist of older cells which are in the stationary growth phase. Considering these parameters, which affect the entire cultivation process, reproducible results and reliable solvent production are ensured.
Muscle function is compromised by gravitational unloading in space affecting overall musculoskeletal health. Astronauts perform daily exercise programmes to mitigate these effects but knowing which muscles to target would optimise effectiveness. Accurate inflight assessment to inform exercise programmes is critical due to lack of technologies suitable for spaceflight. Changes in mechanical properties indicate muscle health status and can be measured rapidly and non-invasively using novel technology. A hand-held MyotonPRO device enabled monitoring of muscle health for the first time in spaceflight (> 180 days). Greater/maintained stiffness indicated countermeasures were effective. Tissue stiffness was preserved in the majority of muscles (neck, shoulder, back, thigh) but Tibialis Anterior (foot lever muscle) stiffness decreased inflight vs. preflight (p < 0.0001; mean difference 149 N/m) in all 12 crewmembers. The calf muscles showed opposing effects, Gastrocnemius increasing in stiffness Soleus decreasing. Selective stiffness decrements indicate lack of preservation despite daily inflight countermeasures. This calls for more targeted exercises for lower leg muscles with vital roles as ankle joint stabilizers and in gait. Muscle stiffness is a digital biomarker for risk monitoring during future planetary explorations (Moon, Mars), for healthcare management in challenging environments or clinical disorders in people on Earth, to enable effective tailored exercise programmes.
The book covers various numerical field simulation methods, nonlinear circuit technology and its MF-S- and X-parameters, as well as state-of-the-art power amplifier techniques. It also describes newly presented oscillators and the emerging field of GHz plasma technology. Furthermore, it addresses aspects such as waveguides, mixers, phase-locked loops, antennas, and propagation effects, in combination with the bachelor's book 'High-Frequency Engineering,' encompassing all aspects related to the current state of GHz technology.
Magnetic nanoparticles (MNP) are investigated with great interest for biomedical applications in diagnostics (e.g. imaging: magnetic particle imaging (MPI)), therapeutics (e.g. hyperthermia: magnetic fluid hyperthermia (MFH)) and multi-purpose biosensing (e.g. magnetic immunoassays (MIA)). What all of these applications have in common is that they are based on the unique magnetic relaxation mechanisms of MNP in an alternating magnetic field (AMF). While MFH and MPI are currently the most prominent examples of biomedical applications, here we present results on the relatively new biosensing application of frequency mixing magnetic detection (FMMD) from a simulation perspective. In general, we ask how the key parameters of MNP (core size and magnetic anisotropy) affect the FMMD signal: by varying the core size, we investigate the effect of the magnetic volume per MNP; and by changing the effective magnetic anisotropy, we study the MNPs’ flexibility to leave its preferred magnetization direction. From this, we predict the most effective combination of MNP core size and magnetic anisotropy for maximum signal generation.
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.
Due to the transition to renewable energies, electricity markets need to be made fit for purpose. To enable the comparison of different energy market designs, modeling tools covering market actors and their heterogeneous behavior are needed. Agent-based models are ideally suited for this task. Such models can be used to simulate and analyze changes to market design or market mechanisms and their impact on market dynamics. In this paper, we conduct an evaluation and comparison of two actively developed open-source energy market simulation models. The two models, namely AMIRIS and ASSUME, are both designed to simulate future energy markets using an agent-based approach. The assessment encompasses modelling features and techniques, model performance, as well as a comparison of model results, which can serve as a blueprint for future comparative studies of simulation models. The main comparison dataset includes data of Germany in 2019 and simulates the Day-Ahead market and participating actors as individual agents. Both models are comparable close to the benchmark dataset with a MAE between 5.6 and 6.4 €/MWh while also modeling the actual dispatch realistically.
Frequency mixing magnetic detection (FMMD) is a sensitive and selective technique to detect magnetic nanoparticles (MNPs) serving as probes for binding biological targets. Its principle relies on the nonlinear magnetic relaxation dynamics of a particle ensemble interacting with a dual frequency external magnetic field. In order to increase its sensitivity, lower its limit of detection and overall improve its applicability in biosensing, matching combinations of external field parameters and internal particle properties are being sought to advance FMMD. In this study, we systematically probe the aforementioned interaction with coupled Néel–Brownian dynamic relaxation simulations to examine how key MNP properties as well as applied field parameters affect the frequency mixing signal generation. It is found that the core size of MNPs dominates their nonlinear magnetic response, with the strongest contributions from the largest particles. The drive field amplitude dominates the shape of the field-dependent response, whereas effective anisotropy and hydrodynamic size of the particles only weakly influence the signal generation in FMMD. For tailoring the MNP properties and parameters of the setup towards optimal FMMD signal generation, our findings suggest choosing large particles of core sizes dc > 25 nm nm with narrow size distributions (σ < 0.1) to minimize the required drive field amplitude. This allows potential improvements of FMMD as a stand-alone application, as well as advances in magnetic particle imaging, hyperthermia and magnetic immunoassays.
The thermal conductivity of components manufactured using Laser Powder Bed Fusion (LPBF), also called Selective Laser Melting (SLM), plays an important role in their processing. Not only does a reduced thermal conductivity cause residual stresses during the process, but it also makes subsequent processes such as the welding of LPBF components more difficult. This article uses 316L stainless steel samples to investigate whether and to what extent the thermal conductivity of specimens can be influenced by different LPBF parameters. To this end, samples are set up using different parameters, orientations, and powder conditions and measured by a heat flow meter using stationary analysis. The heat flow meter set-up used in this study achieves good reproducibility and high measurement accuracy, so that comparative measurements between the various LPBF influencing factors to be tested are possible. In summary, the series of measurements show that the residual porosity of the components has the greatest influence on conductivity. The degradation of the powder due to increased recycling also appears to be detectable. The build-up direction shows no detectable effect in the measurement series.
This easy-to-understand introduction to SAP S/4HANA guides you through the central processes in sales, purchasing and procurement, finance, production, and warehouse management using the model company Global Bike. Familiarize yourself with the basics of business administration, the relevant organizational data, master data, and transactional data, as well as a selection of core business processes in SAP. Using practical examples and tutorials, you will soon become an SAP S/4HANA professional!
Tutorials and exercises for beginners, advanced users, and experts make it easy for you to practice your new knowledge. The prerequisite for this book is access to an SAP S/4HANA client with Global Bike version 4.1.
- Business fundamentals and processes in the SAP system
- Sales, purchasing and procurement, production, finance, and warehouse management
- Tutorials at different qualification levels, exercises, and recap of case studies
- Includes extensive download material for students, lecturers, and professors