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IO information-based component relevance estimation in a mixed-signal ASIC analog circuit
No full textWith increasing demand for active sensor surface and compact modularization, monolithic active pixel sensors are gaining track in high-energy physics experiments. The analog circuits in these mixed-signal ASICs are often black boxes where the components’ function and the circuitry’s behavior can only be evaluated through simulation or educated guesses. Further, parameters acting on these components are often present, allowing the tuning of the behavior towards optimal performance of the circuitry while in operation. These parameters span a multidimensional feature space that is highly intertwined, making precise predictions of their influence on the sensor performance challenging. An approach to evaluate the interplay and importance of these parameters based on Shapley values is presented, which can provide information about the implemented circuit on the ASIC. We show how input–output information can be used, to assess the importance and influence of the components in the analog circuit on the performance of an exemplary pixel sensor. The resulting increase in information can help to evaluate the best tuning parameters of the circuit respective to the present requirements of the users as well as generate valuable feedback for designers guaranteeing the optimal performance of the sensor
Cell-instructive microfibers enable programmable alignment of bioprinted hMSC
No full textBiofabrication of hierarchical tissues with features ranging various size ranges and controllable anisotropy remains a challenge in 3D-bioprinting. To overcome this hurdle, the application of multi-functional microfibers acting as cell-instructive bioink additive, recently gained particular attention. In this work, we investigate a microfluidic spinning process for the fabrication of collagen microfibers with adjustable diameters ranging from 5 to 50 μm. The thread was collected on a rotating winder and fragmented into microfibers of defined length (60–300 μm). By integrating microfiber fragments into an agarose-hyaluronan hydrogel, fine-tuning of its viscosity range (10–1000 mPa∗s), and thus the precise control of the extruded strands’ diameter (0.3–1.4 mm) was achieved. While remaining strong shear-thinning behavior (n-value 0.6), E-modulus and yield stress were decreased in fiber-filled hydrogel, hinting at an interaction of agarose polymer chains with microfibers. Remarkably, the orientation of collagen microfibers could be directed either parallel or orthogonal to the printing path. This allows the biofabrication of hydrogel structures with adjustable domains of defined anisotropy. Finally, the fibers showed excellent biofunctionality both in 2D and 3D. Besides a high degree of alignment of individual cells along the microfiber axis (>80 of cells), hMSCs built a dense, branched network in 3D. Moreover, PC12 and C2C12 were successfully differentiated in 2D and 3D. Specifically, neurite length was higher on smaller fiber diameters, even spanning non-adjacent clusters. Elongated, multi-nuclei myotubes were formed, indicating C2C12 differentiation. In summary, the work demonstrates the great potential of 3D-bioprinting in cross-scale organization of fragmented collagen microfibers
Dislocation response to electric fields in strontium titanate: a mesoscale indentation study
No full textDislocations in perovskite oxides have drawn increasing research interest due to their potential for tuning functional properties of electroceramics. Open questions remain regarding the stability of dislocations under strong externally applied electric fields. In this study, we investigate the dielectric breakdown strength of nominally undoped SrTiO 3 crystals after the introduction of high-density dislocations. The dislocation-rich samples are prepared using the Brinell scratching method, and they consistently exhibit lower dielectric breakdown strength as well as a larger scatter in the breakdown probability. We also study the impact of an electric field on the introduction and movement of dislocations in SrTiO 3 crystals using Brinell indentation coupled with an electric field of 2 kV/mm. No visible changes in the dislocation plastic zone size, depth, and dislocation distribution are observed under this electric field. Based on the charge state of the dislocations in SrTiO3 as well as the electrical and thermal conductivity modified by dislocations, we discuss the forces induced by the electric field to act on the dislocations to underline the possible mechanisms for such dislocation behavior
The Algorithm and the Crowd: A Design Science Research Approach to the Democratization of Algorithmic Management
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Single‐source precursor synthesis of a compositionally complex early transitional metal nitride (V, Nb, Ta, Mo, W)N x and its high temperature stability
No full textCompositionally complex transitional metal nitrides are an interesting class of ceramics with superior chemical, thermal, and mechanical stability, with a high potential in ultra‐high temperature applications and catalysis. The exceptionality in the properties may partly be explained as a consequence of their high configuration entropy. Although promising candidates, the bulk synthesis of compositionally complex metal (carbo)nitrides remains challenging, often limited by purity and scalability due to significant oxygen contamination from gaseous reactants or nitrogen loss. To offset these disadvantages, the current manuscript proposes an alternative synthesis route for the synthesis of a compositionally complex nitride (V, Nb, Ta, Mo, W)N x , which deviates from the typical solid‐state and sputtering methods by employing an organometallic precursor route and a double ammonolysis process. This is a first attempt to synthesize such ceramics with low oxygen contamination in compositionally complex (carbo)nitrides with a scalable production . Using a multidisciplinary approach consisting of theoretical methods and experiments, the current study elucidates the evolution and stability of the precursor at high temperatures under carbon, and thereby obtained ceramics at different temperatures
Efficiency of advanced oxidation processes for treating wastewater from lithium-ion battery recycling
No full textA treatment process was developed for effluents from direct physical lithium-ion battery (LIB) recycling with a focus on the removal of organic contaminants. The high chemical oxygen demand to biological oxygen demand ratio (COD/BOD5) of 3.9–4.6 indicates that biological treatment is not feasible. Therefore, three advanced oxidation processes were evaluated: UV/H2O2 oxidation, the Fenton process and electrochemical oxidation. Two target scenarios were considered, namely compliance with the limit for discharge into the sewer system (COD = 800 mg/L) and compliance with the stricter limit for direct discharge into surface waters (COD = 200 mg/L). Under the investigated conditions, UV/H2O2 oxidation and the Fenton process did not meet the required discharge limits and exhibited high chemical consumption. In contrast, electrochemical oxidation achieved both discharge criteria with a lower energy demand, requiring 32.8 kWh/kgCODremoved for sewer discharge and 95.3 kWh/kgCODremoved for direct discharge. An economic assessment further identified electrochemical oxidation as the most cost-effective option, with treatment costs of EUR 6.63/m3, compared to EUR 17.31/m3 for UV/H2O2 oxidation and EUR 28.66/m3 for the Fenton process. Overall, electrochemical oxidation proved to be the most efficient and environmentally favorable technology for treating wastewater from LIB recycling, enabling compliance with strict discharge regulations while minimizing the chemical and energy demand
Exposía: Academic Writing Assessment of Exposés and Peer Feedback
No full textWe present Exposía, the first public dataset that connects writing and feedback assessment in higher education, enabling research on educationally grounded approaches to academic writing evaluation. Exposía includes student research project proposals and peer and instructor feedback consisting of comments and free-text reviews. The dataset was collected in the "Introduction to Scientific Work" course of the Computer Science undergraduate program that focuses on teaching academic writing skills and providing peer feedback on academic writing. Exposía reflects the multi-stage nature of the academic writing process that includes drafting, providing and receiving feedback, and revising the writing based on the feedback received. Both the project proposals and peer feedback are accompanied by human assessment scores based on a fine-grained, pedagogically-grounded schema for writing and feedback assessment that we develop.
We use Exposía to benchmark state-of-the-art open-source large language models (LLMs) for two tasks: automated scoring of (1) the proposals and (2) the student reviews. The strongest LLMs attain high agreement on scoring aspects that require little domain knowledge but degrade on dimensions evaluating content, in line with human agreement values. We find that LLMs align better with the human instructors giving high scores. Finally, we establish that a prompting strategy that scores multiple aspects of the writing together is the most effective, an important finding for classroom deployment
Oxygen vacancy engineering in lead-free piezoelectric ceramics for performance optimization
No full textPiezoelectric ceramics, renowned for their efficient conversion
between electrical and mechanical energy, have been widely used
in a variety of technologies. For decades, lead-based ceramics
have dominated the market due to their superior performance
and easily tunable functional properties [1]. However, increasing
regulatory pressure to restrict the use of lead has intensified the
pursuit of environmentally benign alternatives [2]. Among the
various lead-free systems, potassium sodium niobate (KNN),
bismuth sodium titanate (BNT), and barium titanate have
emerged as promising candidates [3]. Nevertheless, their overall
performance, including piezoelectric coefficient, mechanical
quality factor, dielectric loss, Curie temperature, and thermal
stability, still lags behind that of their lead-based counterparts. In
recent years, oxygen vacancy engineering has emerged as a
promising strategy to overcome these limitations, enabling
simultaneous optimization of multiple functional properties
through defect modulation
Fast Reconfiguration of Liquid Crystal-RISs: Modeling and Algorithm Design
No full textLiquid crystal (LC) technology is a promising hardware solution for realizing extremely large reconfigurable intelligent surfaces (RISs) due to its advantages in cost-effectiveness, scalability, energy efficiency, and continuous phase shift tunability. However, the slow response time of the liquid crystal (LC)-RIS phase shifters, especially in comparison to the silicon-based alternatives like radio frequency switches and positive-intrinsic-negative (PIN) diodes, limits the performance. This limitation becomes particularly relevant in time-division multiple-access (TDMA) applications where RIS must sequentially serve users in different locations, as the phase-shifting response time of LC-RIS phase shifters can constrain system performance. This paper addresses the slow phase-shifting limitation of LC by developing a physics-based model for the time response of an LC unit cell and proposing a novel phase-shift design framework to reduce the transition time. Specifically, exploiting the fact that LC-RIS at millimeter wave (mmWave) bands have a large number of elements, we optimize the LC phase shifts based on user locations, eliminating the need for full channel state information (CSI) and minimizing reconfiguration overhead. Moreover, instead of focusing on a single point, the RIS phase shifters are designed to optimize coverage over an area. This enhances communication reliability for mobile users and mitigates performance degradation due to user location estimation errors. The proposed RIS phase-shift design minimizes the transition time between configurations, a critical requirement for TDMA schemes. Our analysis reveals that the impact of RIS reconfiguration time on system throughput becomes particularly significant when TDMA intervals are comparable to the reconfiguration time. In such scenarios, optimizing the phase-shift design helps mitigate performance degradation while ensuring specific quality of service requirements. Moreover, the proposed algorithm has been tested through experimental evaluations, which demonstrate that it also performs effectively in practice