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Effect of Scatter Direction on the Maximum Likelihood Evaluation of Bilinear S-N Curves
No full text382391The statistical evaluation of S-N curves plays a central role in fatigue analysis, especially under the constraint of limited test data and the presence of runouts. While traditional approaches focus on modeling uncertainty in the fatigue-life direction, this study investigates four different evaluation strategies for the bilinear Basquin model using maximum likelihood estimation: (1) minimization in the fatigue-life direction, (2) minimization in the load direction, (3) a hybrid piecewise transformation approach, and (4) a novel hybrid pointwise transformation approach. All models are formulated within a consistent probabilistic framework based on a log-normal distribution. A systematic Monte Carlo study examines the performance of these strategies under variation of key parameters such as the number of data points, the logarithmic standard deviation, and the runout ratio. The results show that the commonly used evaluation in the fatigue-life direction yields the poorest parameter estimates. The load-based evaluation performs well in estimating the load amplitude at the knee point and the corresponding fatigue life, but struggles with slope accuracy due to truncation effects. The newly introduced pointwise transformation and the piecewise transformation improve robustness for higher runout ratios. Overall, load-based evaluation performs best at low runout ratios, whereas piecewise and pointwise evaluations outperform under higher censoring. These findings contribute to a better understanding of the directional assumptions in statistical S-N modeling and support the development of more reliable fatigue assessment methods.7
Participatory governance in public research organizations
No full text388410Purpose: Due to growing expectations for academia to address complex societal challenges in inclusive and transparent ways, the question arises of how public engagement can be embedded not only within research projects but also in the governance structures of research organizations. Drawing on case studies of ministerial research institutes (MRIs), this paper aims to examine the institutional and ethical conditions under which participatory practices can be implemented and sustained. MRIs are a distinct type of publicly funded research organization operating at the intersection of science and policy, directly affiliated with government ministries.
Design/methodology/approach: This study uses a qualitative multiple case study design focused on three German MRIs. It is based on 26 semistructured expert interviews, supported by document analysis and observations. The COM-B model (capability, opportunity, motivation - behavior) serves as an analytical framework to explore enabling and constraining factors.
Findings: This study reveals a gap between normative commitments to participation and their institutional realization. This is shaped by limitations in capability (e.g. methodological and dialogical skills); opportunity (e.g. strategic anchoring and support); and motivation (e.g. recognition and incentives), but also highlights existing capacities and initiatives as entry points for change.
Originality/value: While established in behavioral science, the COM-B model is applied here for the first time to participatory governance and organizational change. This paper develops a three-level intervention model - micro, meso and macro - to guide the implementation of participation in research institutions.22
Characterization of AlSiCu/TiN/p-Si Schottky Contacts with Nanophotonic Structures for Near-infrared Photodetectors
No full textSchottky photodetectors based on internal photoemission have the potential of an adjustable detection range in the near-infrared range and Si compatible technology integration. The external quantum efficiency of Schottky photodetectors can be improved using nanophotonic structures, which enhance the absorption of the device. However, the electrical properties of Schottky photodetectors deviate under an altered metal-semiconductor interface topography. We characterize a common layer system for metal contacts consisting of a TiN interstitial layer between the p-Si wafer and the AlSiCu metallization. By varying the thickness of the TiN we discuss how homogeneity of the sputtered layers influence device properties with different interface topographies. Through electrical wafer-level characterization, the characteristics of the Schottky contact are evaluated and compared to the ideal physical modelling
Chemical Recycling of Plastic Waste: Comparative Evaluation of Environmental and Economic Performances of Gasification- and Incineration-based Treatment for Lightweight Packaging Waste
No full text13691398Chemical recycling (CR) – in enabling the use of plastic waste back as secondary carbon feedstock for production – could play a complementary role to mechanical recycling in supporting the transformation from a linear to a circular carbon economy. To date, research has predominantly focused on assessing technological aspects associated with CR of pure plastic waste streams. Little is known about its potential for treating low-quality and mixed plastic waste fractions which are unsuitable for conventional recycling and are currently incinerated. To address this gap, this investigation utilizes an integrated approach comprising of life cycle assessment and techno-economic analysis to evaluate the environmental and economic performance of CR of lightweight packaging waste via waste gasification compared to direct and indirect incineration in Germany. Results show that CR can contribute significantly – irrespective of the energy mix – to reducing climate change, terrestrial acidification, and fossil resource scarcity. In terms of economic performance, findings suggest that while CR requires higher capital investment, a multi-pronged approach which encompasses upscaling, waiver of carbon dioxide certificate costs, and price premium for CR products could increase profitability of CR to incineration. This study provides empirical support for the potential contribution of CR to complement existing strategies to combat the plastic waste challenge, and insights into market conditions which could promote its economic attractiveness. Additionally, it provides comprehensive inventory data for conventional and alternative waste treatment plants for lightweight packaging waste to inform future research on systemic assessment of CR technologies and their contributions to a circular economy.2
Influence of the reinforcement phase of MAX phase composites during ultra-precision grinding
No full textThis study investigates various configurations of a MAX phase composite (Ti3SiC2 + TiC) concerning their machinability within the context of mold manufacturing for Precision Glass Molding (PGM). The composite material is machined using ultra-precision (UP) grinding. The aim of this research is to understand the achievable roughness through this manufacturing process, as well as the wear behavior of the grinding tools, depending on the material configuration - specifically the volume percentage (vol.-%) of the TiC reinforcement phase. Using a confocal microscope, surface roughness parameters, including Sq and Sa, were chosen to quantitatively assess surface accuracy. Furthermore, tool wear was monitored by a microscope camera. Due to the novelty of this material, there is a lack of existing knowledge regarding its UP grinding characteristics; hence, various grinding tool configurations and process parameters are varied in the experiments. The findings indicate that surface roughness is not significantly influenced by the material composition (vol.-% TiC). A ductile machining process can be achieved by maintaining a critical chip thickness, regardless of the chemical composition. Consequently, the experiments demonstrate that surface roughness values of Sq < 5 nm are attainable, satisfying the surface quality requirements for applications in precision glass molding. However, the results of the wear tests show that the material composition has a significant influence on the tool wear
Correction to: Glucose and Inositol Transporters, SLC5A1 and SLC5A3, in Glioblastoma Cell Migration (Cancers, (2022), 14, 23, (5794), 10.3390/cancers14235794)
No full textPhilipp Kreisz was not included as an author in the original publication [1]. The corrected Author Contributions Statement appears here. The authors apologize for any inconvenience caused, and state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.152
Laser-aided additive manufacturing of pure copper part using laser radiation in the NIR spectral range Lasergestützte Additive Fertigung reiner Kupferbauteile unter Einsatz von Laserstrahlung im NIR-Spektralbereich
No full text4004027511-1
Group-index-matched frequency conversion in lithium niobate on insulator waveguides
No full textSources of spectrally engineered photonic states are a key resource in several quantum technologies. Of particular importance are the so-called factorizable biphoton states, which possess no spectral entanglement and hence, are ideal for heralded generation of high-purity single photons. An essential prerequisite for generating these states through nonlinear frequency conversion is the control over the group indices of the photonic modes of the source. Here, we show that thin-film lithium niobate on insulator (LNOI) is an excellent platform for this purpose. We design and fabricate periodically poled ridge waveguides in LNOI to demonstrate group index engineering of its guided photonic modes and harness this control to experimentally realize on-chip group index matched type-II sum-frequency generation (SFG). Also, we numerically study the role of the top cladding layer in tuning the dispersion properties of the ridge waveguide structures and reveal a distinctive difference between the air and silica-clad designs which are currently among the two most common device cladding configurations in LNOI. We expect that these results will be relevant for various classical and quantum applications where dispersion control is crucial in tailoring the nonlinear response of the LNOI-based devices.
Enhanced No-Code Finger-Gesture-Based Robot Programming: Simultaneous Path and Contour Awareness for Orientation Estimation
No full text15021508The programming of industrial robots necessitates specialized expertise and significant time and effort, particularly for small batch sizes. However, with the increasing demand for agility in production, the solutions used for robot programming have evolved significantly. Intuitive robot programming systems based on diverse concepts have been introduced to facilitate rapid deployment of robot systems. One such approved concept is no-code robot programming with finger-based gesture. In this concept, non-expert users draw a robot path via finger movement, which is subsequently translated into robot programming language to facilitate the corresponding movement. A significant challenge associated with this method is the valid replication of the corresponding robot Tool Center Point (TCP) orientation. Reachability issues, non-compliant hand contortions, and sensor occlusions make it difficult to directly derive the robot's TCP orientation from the finger's orientation. This work presents two novel approaches for estimating robot orientation using numerical analysis and point cloud information for finger-based robot programming without requiring prior knowledge. The first approach utilizes numerical analysis to estimate the relative robot orientation based on the geometry of the trajectory. In contrast, the second approach uses point-cloud to derive the robot orientation based on the object contour. Input shaping algorithms are employed and evaluated to reduce the divergence in the orientation estimations. Experiments demonstrate the effectiveness of the proposed approach utilizing a low-cost camera as a cost-efficient alternative to existing no-code programming strategies, potentially accelerating the real-world deployment of robotic applications in industrial environments
A novel reconfigurable RF switch based on ferroelectric hafnium oxide FeFET fabricated in 22 nm FDSOI technology
No full text181184This paper presents a novel type of ferroelectric field effect transistor (FeFET)-based RF switch with multiple finger structure fabricated in 22 ~nm FDSOI technology. The ability to adjust the threshold voltage non-volatile allows for a novel switch concept. The FeFET can operate at V_GS=\mathbf0, which reduces the necessity of bias-Tee configurations in the signal path. It combines the advantages of passive and active RF switches with low loss and low distortion. The devices were implemented in the common-source configuration and demonstrate a large memory window exceeding 2 ~V, as well as exceptional performance at mmWave frequencies. We determined a transit frequency \left(f_T\right) and maximum oscillation frequency (f_MAX) of 135GHz and 139GHz, respectively for a device with 16 fingers, 20 ~nm gate length, and 1 \mu m gate width