335598 research outputs found
Sort by
Distributed model predictive control for district heating networks considering building and network flexibility
No full textThe grid-responsive operation of large-scale heat pumps in District Heating Networks (DHNs) requires advanced control strategies to coordinate the DHNs’ inherent thermal storage with power grid demands. The present work introduces a Distributed Model Predictive Control (DMPC) that leverages both building-level and network-level flexibility to adjust heat pump operation in response to dynamic pricing. The DMPC is based on the Alternating Direction Method of Multipliers algorithm to avoid privacy-critical information flows and improve scalability compared to standard centralized MPC (CMPC). To achieve this, each building solves a local control problem and exchanges only non-sensitive information with the DHN operator. The DMPC is comprehensively compared against a CMPC on a literature-based benchmark DHN across nine one-week simulation scenarios varying in price and weather conditions. The DMPC successfully achieves control performance comparable to the CMPC with excess costs below 1.5% while maintaining thermal comfort and avoiding privacy-critical information flow. Additionally, the computation time is reduced by 15.5% to 74.3% compared to the CMPC, highlighting the improved scalability. The computation time savings substantially depend on the number of iterations necessary for the DMPC to converge, emphasizing the importance of avoiding excess iterations. These results highlight the potential of distributed control to facilitate scalable, privacy-preserving, and efficient demand response in future DHNs
Impact of harvesting via flocculation on protein yield from Chlorella vulgaris following pulsed electric field and high-pressure homogenization treatments
No full textThe growing interest in sustainable biomass sources has encouraged research on microalgae, particularly focusing on improving the efficiency of cell separation and extraction processes. Currently, the harvesting step is primarily performed by centrifugation, which requires high energy consumption, especially for large-scale cultivation volumes. Therefore, this study aimed to explore coagulation/flocculation as an alternative harvesting method for Chlorella vulgaris, using FeCl2, FeCl3, and chitosan. Additionally, this study aimed to evaluate the effect of the different flocculants on subsequent protein extraction, comparing extraction yields obtained by pulsed electric field (PEF) and high-pressure homogenization (HPH) treatment for the first time. The results indicated that FeCl3 had the highest flocculation efficiency, reaching over 99% with a lower dosage than the other flocculants (200 mg L 1). Although FeCl₃ achieved the highest flocculation efficiency (over 99% at a low dosage of 200 mg⋅L 1), the subsequent protein extraction yields were lower compared to centrifuged biomass. Protein recovery from FeCl₃-flocculated biomass reached only 9.22% of cell dry weight (CDW) with HPH and 0.5% of CDW with PEF, whereas centrifugation resulted in higher yields of 49.4% and 19.5% of CDW, respectively. These results indicate that while floc formation is effective for biomass harvesting, it may hinder protein extraction and reduce biomolecule recovery. Additionally, the protein profile analyzed by SDS-PAGE confirmed the negative impact of using flocculants, showing a disappearance or reduction of bands
Advancing Brainwave-Based Biometrics: A Large-Scale, Multi-Session Evaluation
No full textThe field of brainwave-based biometrics has gained attention for its potential to revolutionize user authentication through hands-free interaction, resistance to shoulder surfing, continuous authentication, and revocability. However, current research often relies on single-session or limited-session datasets with fewer than 55 subjects, raising concerns about the generalizability of the findings. To address this gap, we conducted a large-scale study using a public brainwave dataset comprising 345 subjects and over 6,007 sessions (an average of 17 per subject) recorded over five years using three headsets. Our results reveal that deep learning approaches significantly outperform hand-crafted feature extraction methods. We also observe Equal Error Rates (EER) increases over time (e.g., from 6.7% after 1 day to 14.3% after a year). Therefore, it is necessary to reinforce the enrollment set after successful login attempts. Moreover, we demonstrate that fewer brainwave measurement sensors can be used, with an acceptable increase in EER, which is necessary for transitioning from medical-grade to affordable consumer-grade devices. Finally, we compared our results to prior work and existing biometric standards. While our performance is on par with or exceeds previous approaches, it still falls short of industrial benchmarks. Based on the results, we hypothesize that further improvements are possible with larger training sets. To support future research, we have open-sourced our analysis code
Harnessing Substituted 4-Chlorothieno[2,3-b]pyridine as a New Cap for Potent and Selective Antiproliferative HDAC Inhibitors
No full textBackground: Inhibition of histone deacetylase is a highly sought-after objective in the fight against cancer. Thus, the development of innovative HDAC inhibitors with significantly higher potency than SAHA against specific cancer cell types represents complex and demanding work.
Method: The utilization of the underexplored and privileged scaffold
4-chlorothieno[2,3-b]pyridine as a cap tethering diverse aliphatic and aromatic linkers, followed by the screening of both cellular and enzymatic activities, is undertaken in this study.
Results: Compounds 7a and 9a demonstrated impressive mean GI values of 2.15 μM and1.89 μM, respectively. Both compounds reduced caspase-3 levels in RPMI-8226 cells, suggesting induction of apoptosis. Compound 7a showed remarkable IC values of 0.37 μM, 0.58 μM, and 0.70 μM against HDACs 1, 4, and 6, respectively, consistent with the cellular assay. Additionally, compound 7a exhibited a selectivity index of 11 for RPMI-8226 cells over PBMCs, reflecting its high selectivity and potential safety. Moreover, ADMET prediction tools indicated that compounds 7a and 9b may have more favorable pharmacokinetic properties than the gold-standard HDAC inhibitor, SAHA.
Conclusions: Further study and
exploration of the derivatives of compounds 7a and 9a can lead to further advancement in the development of potent HDAC inhibitor anticancer drugs
Rethinking performance crises in professional soccer: German coaches’ insights into systemic vulnerabilities and escalating dynamics
No full textProfessional soccer, as a global phenomenon, is characterized not only by outstanding performances but also by frequent and sometimes prolonged periods of underperformance, which represent performance crises. Despite the growing body of research on performance crisis, the specific perspectives of coaches remain underexplored. Previous studies have largely focused on players’ viewpoints, resulting in a lack of understanding of the systemic and escalating dynamics of crises from the perspective of those in leadership positions. This study addresses this gap by investigating how professional soccer coaches perceive the development and persistence of performance crises in professional soccer. Employing a qualitative research design, twelve professional coaches with diverse roles (head coaches, assistant coaches, and goalkeeper coaches), a mean age of 43 years (range: 32–51), and extensive coaching experience in professional soccer (7–23 years, M = 15.5) were interviewed. The interviews were analyzed using data-driven and concept-driven content analysis based on thematic qualitative text analysis. The analysis reveals that performance crises are not attributable to isolated incidents but rather arise from the interplay between pre-crisis vulnerabilities, their transition to crisis dynamics, acute triggers, and escalating dynamics at team, organizational, and external levels. Pre-crisis vulnerabilities include latent factors such as organizational incongruence, and fragile team cohesion, that increase susceptibility to crises. Notably, coaches emphasized that success temporarily masks these underlying tensions, which surface and intensify when performance declines. Acute triggers refer to specific disruptive events or negative results that catalyze instability and initiate the crisis process. Escalating dynamics describe the self-reinforcing processes whereby psychological, social, and structural problems perpetuate and deepen the crisis. The study advances the field by highlighting systemic, self-reinforcing cycles of crisis and organizational incongruence that undermine coaching authority. These insights have practical implications for improving leadership coherence and resilience strategies in professional sports environments
Enhancing Selectivity in Affinity Biosensors through Biorecognition-Driven Suppression of Nonspecific Binding
No full textElectrochemical Synthesis of 1,2-Substituted N -Amido Benzimidazoles by Reduction of Nitroarenes
No full textDespite the vast number of reports on benzimidazoles, 1,2-substituted N-amido benzimidazoles remain an underrepresented and scarcely accessible compound class with promisingpharmacological relevance. We present a safe, reliable electrochemical protocol that provides easy access to those structures. The reaction exhibits broad functional group tolerance and affords the target compounds in ≤89% yields
Keramikverstärkte Aluminiumwerkstoffe für das pulverbettbasierte selektive Laserschmelzen : Beschichtung, Werkstoff- und Oberflächeneigenschaften von Mikro-B4C- und Nano-TiC-verstärkten AlSi10Mg- Feedstocks, verarbeitet im PBF-LB-Prozess
No full textIn der europäischen Union (EU) sollen ab 2045 u. a. innovative gewichtsreduzierte Flugzeugtypen klimaneutral betrieben werden. Im Fokus der vorliegenden Arbeit steht die rissfreie Verarbeitung von neuen hochfesten Aluminium-Leichtbauwerkstoffen ohne das als kritisch von der EU eingestufte Element Scandium, die mittels pulverbettbasiertem selektiven Laserschmelzen (PBF-LB) verarbeitet werden können. Die Mischung von 6 µm B4C-Partikeln mit AlSi10Mg-Pulver ist dazu ein Ansatz. Eine neu entwickelte Breitbandultraschallanregung der Beschichtungsgeometrie ermöglicht Feedstocks mit bis zu 20 Vol% B4C und in Kombination mit einer TiC-Nanopartikel-beschichtung bis zu 25 Vol% B4C fehlerfrei aufzurakeln. Mit steigender Zugabe der B4C-Partikel nehmen die Eigenspannungen in der Matrix zu und sind ab 10 Vol% B4C höher als die Festigkeit der Matrix. Zusätzlich wird beobachtet, dass Konturprozessstellgrößen nicht angepasst werden müssen und sich die Rauheit um 50 % gegenüber reinem AlSi10Mg reduziert, ohne dass oberflächennahe Poren entstehen. Durch diese Arbeit sind Grundlagen geschaffen, Feedstocks zu mischen, im PBF-LB-Prozess aufzurakeln und aufzubauen. Eine Festigkeitssteigerung tritt nicht ein, weil die Schmelze im PBF-LB-Prozess erstarrt, bevor eine stoffschlüssige Reaktion stattfindet. Dem folgend ist die zukünftige Entwicklung eines heißisostatischen Pressprozesses notwendig, durch den eine stoffschlüssige Reaktion unterhalb der Schmelztemperatur von AlSi10Mg ausgelöst wird. T6-Wärmebehandlungen und Direktauslagern sind nicht geeignet
