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Now showing items 11-20 of 142
Aufsatz
Investigating Motivational and Cognitive Factors which Impact the Success of Engineering Students
(2021-02-06)
Engineering students particularly struggle with mathematics in the first year of their university studies. A result of these difficulties are high drop-out rates among the engineering students. There are various measures to support the students in their studies such as preparatory courses or bridging courses. The contribution of this research is to investigate the impact of certain factors on engineering students’ success in their first year of studies in a supportive environment which includes a preparatory course, ...
Aufsatz
Wie können Systeme künstlicher Intelligenz ohne Qualitätsverlust rechtsverträglich gestaltet werden?
(2020-03-03)
Künstliche intelligente (KI)-Systeme erfreuen sich immer größerer Beliebtheit. Im Alltag erleben wir KI beispielsweise durch smarte persönliche Assistenten (SPAs), welche von Amazon, Google und Co. angeboten werden. Zwar haben diese KI-Systeme große Nutzungspotenziale, gleichzeitig gehen damit aber auch erhebliche Risiken einher, beispielsweise datenschutzrechtliche. Doch wie lassen sich diese Spannungsfelder auflösen? Interdisziplinäre Gestaltungsmuster im Systementwicklungsprozess können eine Lösung darstellen, ...
Aufsatz
First-Order Shape Derivative of the Energy for Elastic Plates with Rigid Inclusions and Interfacial Cracks
(2020-11-16)
Within the framework of Kirchhoff–Love plate theory, we analyze a variational model for elastic plates with rigid inclusions and interfacial cracks. The main feature of the model is a fully coupled nonpenetration condition that involves both the normal component of the longitudinal displacements and the normal derivative of the transverse deflection of the crack faces. Without making any artificial assumptions on the crack geometry and shape variation, we prove that the first-order shape derivative of the potential ...
Aufsatz
Exploiting ferroelectric and ferroelastic effects in piezoelectric energy harvesting: theoretical studies and parameter optimization
(2021-02-18)
While piezoelectric energy harvesting typically focuses on converting mechanical into electrical energy on the basis of the linear reversible piezoelectric effect, the potential of exploiting the non-linear ferroelectric effect is investigated theoretically in this paper. Due to its dissipative nature, domain switching, on the one hand, is basically avoided in order to prevent mechanical energy from being converted into heat. However, the electrical output, on the other hand, is augmented due to the increased change ...
Aufsatz
Renewable Energy Integration for Steam Supply of Industrial Processes—A Food Processing Case Study
(2020-05-16)
This study highlights the CO2,e -emission reduction potentials and related economic consequences for changing steam generation from fossil to renewable. Seven different utility concepts are developed, including a steam accumulator for load management. Peculiarities for the integration of biogas boilers, biomass-fuelled boilers, electrode steam boilers, biomethane-fuelled solid oxide fuel cells, micro gas turbine, solar energy systems, heat pumps and steam accumulators into a steam system with fluctuating steam demand ...
Aufsatz
Comparison between Hyperspectral Imaging and Chemical Analysis of Polyphenol Oxidase Activity on Fresh-Cut Apple Slices
(2020-06-29)
The assessment of the quality of fresh-cut apple slices is important for processing, storage, market value, and consumption. Determination of polyphenol oxidase activity (PPO) in apples is critical for controlling the quality of the final product (i.e., dried apples and juices). Hyperspectral imaging (HSI) is a nondestructive, noncontact, and rapid food quality assessment technique. It has the potential to detect physical and chemical quality attributes of foods such as PPO of apple. The aim of this study was to ...
Aufsatz
Damping based on electromagnetic induction: A comparison of different minimal models
(2021-01-25)
Damping of structural vibrations is a crucial part of modern engineering. Using electromagnetic interactions for this purpose is a modern and promising approach. To gain better understanding of phenomena involved in this technique investigations on minimal models of a B‐field modulation dampers are shown. Therefore two different setups are compared. One uses a permanent magnet as the source for the magnetic field, one uses a coil, respectively an electro‐magnet as the source. The contribution focuses on differences ...
Aufsatz
Derivation of Analytical, Closed‐form Formulas for the Calculations of Instantaneous Screw Axes of Arbitrary Rigid 3D Multi‐Body Systems
(2021-01-25)
A method to calculate the parameters for each instantaneous and relative instantaneous screw axis in an arbitrary rigid multi‐body system is presented. At first a kinematic analysis is performed which calculates the displacements of all nodes and the rotation of each body. In the next step the displacements of the nodes and the rotation of the bodies are used to calculate the instantaneous screw axis of each body. With the information on the instantaneous screw axes the instantaneous relative screw axes can be computed ...
Aufsatz
Actuation of an elastic membrane by the use of an electrorheological valve
(2021-01-25)
The dynamic response of a fluidic actuator is investigated on the basis of numerical simulations. With this actuator a membrane is excited to oscillate by means of an electrorheological valve. For this purpose the solid and fluid domains are coupled. Furthermore, the constitutive equation of the fluid is coupled to the electric field. The dynamic response is discussed on the example of a variable stiffness of the membrane. Actuators of this type offer the potential to delay the transition of a boundary layer.
Aufsatz
Measuring the Time Discretization Error in Linear Elasticity
(2021-01-25)
The present paper considers the spread of longitudinal waves in an elastic rod. On the one hand an analytical solution is presented, on the other hand a spatially and temporally discretized continuum formulation of this problem is treated. With these approaches at hand the appearing time discretization error is analyzed using various quantities.