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VERITAS and Multiwavelength Observations of the Blazar B3 2247+381 in Response to an IceCube Neutrino Alert
No full textWhile the sources of the diffuse astrophysical neutrino flux detected by the IceCube Neutrino Observatory are still largely unknown, one of the promising methods to improve our understanding of them is investigating the potential temporal and spatial correlations between neutrino alerts and the electromagnetic radiation from blazars. We report on the multiwavelength target-of-opportunity observations of the blazar B3 2247+381, taken in response to an IceCube multiplet alert for a cluster of muon neutrino events compatible with the source location between 2022 May 20 and 2022 November 10. B3 2247+381 was not detected with VERITAS during this time period. The source was found to be in a low-flux state in the optical, ultraviolet, and gamma-ray bands for the time interval corresponding to the neutrino event, but was detected in the hard X-ray band with NuSTAR during this period. We find the multiwavelength spectral energy distribution is described well using a simple one-zone leptonic synchrotron self-Compton radiation model. Moreover, assuming the neutrinos originate from hadronic processes within the jet, the neutrino flux would be accompanied by a photon flux from the cascade emission, and the integrated photon flux required in such a case would significantly exceed the total multiwavelength fluxes and the VERITAS upper limits presented here. The lack of flaring activity observed with VERITAS, combined with the low multiwavelength flux levels, as well as the significance of the neutrino excess being at a 3 sigma level (uncorrected for trials), makes B3 2247+381 an unlikely source of the IceCube multiplet. We conclude that the neutrino excess is likely a background fluctuation
An All-Conjugated, PM6-Based Block Copolymer Enables Stable Nanoparticle Dispersions in Methanol
No full textOrganic semiconductors are commonly processed using toxic halogenated or aromatic solvents due to their poor solubility in less harmful alternatives, leading to significant environmental and health concerns. Although there are "green" solvents available, these materials often face limited processing options and challenges in microstructure control. To mitigate this, an emerging approach involves creating dispersions of organic semiconductor nanoparticles in polar, environmentally friendly solvents. However, achieving stable nanoparticle dispersions without ligands remains a significant challenge. This study introduces a novel method for enhancing the stability of these ligand-free dispersions by developing an amphiphilic conjugated polymer, PM6-FNT, designed to form stable nanoparticles in alcohol-based dispersions. PM6-FNT is synthesized via a one-pot, stepwise Stille cross-coupling polymerization, where an amino group-functionalized fluorene-thiophene copolymer (FNT) chain is grown in situ on preformed PM6 chains. Nanoparticles of PM6-FNT, prepared by nanoprecipitation in polar solvents like alcohols, exhibited exceptional colloidal stability due to the high zeta potential of around 35 mV and controllable particle sizes in the range of 35-200 nm. In contrast, nanoparticle dispersions of PM6 could not be formed under the same conditions. This research highlights the potential of PM6-FNT to address existing challenges in organic semiconductor processing. Using nanoparticles instead of solutions enables enhanced layer-by-layer processing capabilities, morphology control, and higher crystallinity, further optimizing performance and paving the way for the eco-friendly, large-scale production of organic semiconductor devices
The IAEA exercise on probabilistic fault displacement hazard assessment
No full textInternational Atomic Energy Agency (IAEA) Specific Safety Guide SSG-9 (Rev.1) recommends the use of probabilistic fault displacement hazard assessment (PFDHA) for faults that may affect the foundations of safety-related structures of nuclear installations in the specific case of existing nuclear installation sites. To provide practical guidance on performing PFDHA, IAEA initiated an exercise that includes alternative fault displacement predictive models and three case studies representing strike-slip, normal, and reverse earthquakes. This article presents and discusses the findings of the IAEA PFDHA exercise for selected principal and distributed fault displacement scenarios. Analysis of the results underlines that the primary fault displacement estimations by different modelers are in good agreement at the return periods dominated by surface rupture models for exercise cases that involve moderate-to-large magnitude events. At longer return periods, significant differences are observed in the slopes of the hazard curves due to model uncertainties particularly aleatory variability and truncation of the standard deviation. Distributed displacement hazard curves by different modelers have factors of 10-50 differences, mainly caused by different assumptions in the implementation of the problem, particularly in the conditional probability of distributed fault rupturing. The findings of this study highlighted the need for developing a consensus in surface rupture probabilities, especially when multiple fault displacement predictive models are used to capture the epistemic uncertainty in PFDHA estimations
Okul Öncesi Eğitimde Yapay Zekâ Kullanımına İlişkin Öğretmen ve Öğretmen Adayı Görüşleri
No full textTwo-Layer Model Predictive Control of Microgrids: Cost Optimization and Resilience Through Adaptive Setpoint Coordination
No full textWith the growing use of energy storage systems, storing surplus energy from renewable sources has become a profitable strategy. Given the rising trend in the use of renewable energy and the installation of battery storage systems, the significance of microgrids has increased. To ensure microgrid networks perform optimally, operators should maintain resilience for emergencies and cost-effectiveness during normal operating conditions. This study introduces a strategy that addresses these issues, focusing on customer flexibility and computational efficiency through a two-layer integrated model predictive controller. In this framework, setpoints from the upper-layer microgrid operator are issued every 15 minutes to lower-layer building managers, who adjust their operations on a minute basis in response to these setpoints, ensuring effective problem-solving. Additionally, the recommended battery setpoint dispatch substantially lessens the computational load of optimization, especially in larger systems, and achieves the required resilience. Throughout the paper, corresponding methodology and simulation results are presented and verified
Stability assessment of the landslide in a segment of the Bartın Kirazlı Bridge dam Diversion, Western Black Sea Region, Türkiye
No full textThe Bartın Kirazlı Bridge Dam construction has started on Gökırmak stream, western Black Sea Region, for the purposes of irrigation and power generation, and is continuing at present. By the end of construction, it is anticipated that the existing Bartın-Safranbolu Highway will be submerged underwater due to the increase in the Gökırmak stream level. With the start of construction of the new highway alignment for the relocation of the submerged road named as the “Bartın Kirazlı Bridge Dam Diversion”, the paleo-landslide regions alongside the new alignment have been triggered and led to mass movement along a segment of the new highway. This study aims to define the characteristics of this landslide, determine the sliding surface geometry and location, reveal the mobilized mass amount, and specify the appropriate remediation measures for long-term stability. For this purpose, geotechnical investigations and laboratory tests were conducted. With the data obtained from the engineering geological and geotechnical investigations, the landslide geometry and the shear strength parameters of the landslide mass were determined by back analysis. In addition, slope stability analysis was performed by limit equilibrium analyses for both static and dynamic conditions. As a result of these studies, groundwater level reduction by pumping in short-term, rock buttress application after temporary toe excavation and de-watering of the area by surface and subsurface drainage remediation phases were determined to be suitable for the long-term stability of the landslide
Echoes of the Past: How Historical Memory and Religious Narratives Shape Refugee Experiences in Modern Greece
No full textData Imbalance in Large-Scale Face Recognition B y k l ekli Y z Tanimada Veri Dengesizligi
No full textIn this study, proposals have been presented to improve various recognition problems encountered in large-scale face databases related to the open-set face recognition problem. Based on the experiments conducted, the most successful face detection model was determined to be SCRFD-BNKPS. For the face recognition problem, a embedding vector extraction model that provides high discrimination capability was selected from among the ArcFace models. The biggest issue observed when these extracted feature vectors were classified into identity classes using popular nonlinear classifiers was the varying number of identities within each class. To address this, the ROS and ENS algorithms were employed to ensure that classes with a small number of samples provided sufficient feedback to the classifier. Additionally, the k-NN algorithm, used to avoid the need for training a wholesale classifier in the open-set classification problem, was improved using the LMNN metric learning method
Duty Cycle Compatible Fresh Data Tranmission with LoRa LoRa ile G rev D ng s Kisitina Uyumlu Taze Veri Iletimi
No full textLow Power Wide Area Networks (LPWANs) using the ISM band are constrained by serious duty-cycle limitations in Europe and in various other parts of the world. This constraint particularly limits the freshness of IoT data that can be conveyed using these networks. Earlier literature introduced the DutyCycle Compliant Threshold ALOHA (DCCTA), that aims to optimize the age of information (AoI) in a duty-cycle constrained LPWAN setting. In this paper, we report on the implementation of a system where end nodes use DCCTA and LoRa-enabled end nodes. A custom gateway is implemented, to evaluate the performance of our protocol under two cases: end nodes receive or do not receive packet success feedback from the gateway. Measurement and simulation results both reveal that under dutycycle constraints, skipping the feedback achieves significantly better efficiency and data freshness. Our findings, grounded in both simulation and practical implementation, underscore the potential of our protocol in reducing AoI under stringent dutycycle regulations