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Design, Fabrication and Characterization of L&T Hybrid Mode Transducers for Thermoplastic Welding
No full textAbstract Objectives This study aims to present a systematic approach for designing, fabricating and characterizing ultrasonic transducers for thermoplastic sheet welding capable of operating in longitudinal–torsional (L&T) hybrid vibration modes at 20 kHz, driven by an axially poled piezoceramic stack. Methods Multiple horn models featuring circumferential deep helical grooves were designed to generate longitudinal and torsional vibratory displacements. Modal analyses were conducted to determine the appropriate dimensions for the desired mode shape and resonance frequency. The selected horn geometries were integrated with transducer bodies in a CAD environment to build 3D models of ultrasonic transducers. Modal and harmonic analyses were performed to evaluate their mode shapes, resonance frequencies, and displacement amplitudes under various excitation conditions. Prototypes of the optimized designs were fabricated using predetermined materials and geometries and characterized experimentally for resonance frequencies and tip displacements. The experimental results were compared with numerical analyses to validate the approach. Results The developed transducers demonstrated successful operation in L&T hybrid vibration modes at the targeted frequency, with displacement amplitudes and resonance frequencies aligning well with the numerical predictions. Combining exponential area reduction and helical grooves in the horn appears to be a highly effective method for achieving longitudinal-torsional vibration from a longitudinally vibrating transducer. Finite element analysis proved to be a valuable design tool, facilitating accurate dimensional optimization of the horns to achieve the desired L & T hybrid vibrational mode shapes. The apparent longitudinal and torsional (spring) stiffness of the horn significantly influences the longitudinal displacement amplitude and angular displacement at the horn tip. The resonance frequency of the transducers shifted to higher frequencies with increasing excitation voltage. Conclusion This research provides a comprehensive and validated framework for designing ultrasonic transducers capable of operating in hybrid vibration modes. The methodology reliably achieved the desired vibratory performance, with prototype results aligning closely with design objectives.https://doi.org/10.1007/s42417-024-01690-9https://avesis.yildiz.edu.tr/publication/details/fda165d2-0cce-4257-8395-7af5d9f9ba85/oa
Addressing Climate Change Effects on Freshwater Resources: Case Study on Büyükçekmece Lake Water Budget with Zero Liquid Discharge Prospective
No full texthttps://doi.org/10.1007/978-3-031-96134-2_1
Transformer and statistical models for LCSH assignment: a comparative study in digital libraries
No full textPurpose This study aims to examine the effectiveness of machine learning models and ensemble approaches for automating Library of Congress Subject Headings (LCSH) assignment to graduate theses and dissertations, aiming to enhance the efficiency, scalability and accuracy of library subject indexing in the digital age. Design/methodology/approach A comparative quasi-experimental framework assessed five machine learning models (DeBERTa-v3-base, all-mpnet-base-v2, FastText, Omikuji Bonsai, term frequency-inverse document frequency [TF-IDF]) and two ensemble strategies (hybrid: DeBERTa + MPNet; ensemble: FastText + Omikuji Bonsai + TF-IDF) on a dataset of 1,104,600 thesis and dissertation titles across 1,578 LCSH labels, integrating organic and synthetic data. Synthetic titles were generated using large language models and rigorously validated to mitigate bias and prevent dataset imbalance. The performance was evaluated using F1, recall@5, NDCG@5, MRR and computational efficiency metrics (RAM usage and prediction time). Paired t-tests were conducted to confirm statistical significance of key performance differences. Findings Transformer-based models (DeBERTa-v3-base: F1 0.7348; all-mpnet-base-v2: F1 0.7277) excelled in accuracy, whereas statistical models (e.g. FastText: 0.36 MiB, 0.0006 s) offered superior efficiency. The hybrid model achieved the highest F1 (0.7413) and NDCG@5 (0.8130) and the ensemble model led in recall@5 (0.8824), demonstrating the value of model integration. Ablation results showed that synthetic data substantially improved classification and ranking performance of models. Synthetic data improved dataset balance, enhancing model generalization. Originality/value This study provides a novel comparison of transformer-based and statistical machine learning models for LCSH assignment, validated through both ablation and statistical significance testing, pioneering the use of synthetic data and probability-weighted ensembles to improve accuracy and ranking. It offers actionable insights for library automation, bridging gaps in prior research focused on narrower model sets.https://doi.org/10.1108/el-03-2025-010
Dual‐Functioning Metal‐Organic Frameworks: Methotrexate‐Loaded Gadolinium MOFs as Drug Carriers and Radiosensitizers
No full textAbstract Cancer remains a critical global health challenge, necessitating advanced drug delivery systems through innovations in materials science and nanotechnology. This study evaluates gadolinium metal‐organic frameworks (Gd‐MOFs) as potential drug delivery systems for anticancer therapy, particularly when combined with radiotherapy. Gd‐MOFs were synthesized using terephthalic acid and gadolinium (III) chloride hexahydrate and then loaded with methotrexate (MTX). Characterization via fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), magnetic resonance imaging (MRI), and X‐ray diffraction (XRD) confirmed their correct structure and stability. Effective MTX loading and controlled release were demonstrated. Anticancer effects were assessed on human healthy bronchial epithelial cells (BEAS‐2B) and human lung cancer cells (A549) using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay under in vitro radiation therapy. MTX/Gd‐MOF combined with radiotherapy showed a greater reduction in cancer cell viability (41.89% ± 2.75 for A549) compared to healthy cells (56.80% ± 1.97 for BEAS‐2B), indicating selective cytotoxicity. These findings highlight the potential of Gd‐MOFs not only as drug delivery vehicles but also as radiosensitizers, enhancing radiotherapy efficacy and offering promising evidence for their use in combinatory cancer therapies to improve treatment outcomes.https://doi.org/10.1002/chem.202404106https://pubmed.ncbi.nlm.nih.gov/40079794http://dx.doi.org/10.1002/chem.202404106https://hdl.handle.net/20.500.12831/2711
Analysing O3 levels and formation conditions via TROPOMI NO2 and HCHO retrievals for the Aegean Region
No full textTropospheric Ozone (O3) is a secondary pollutant formed via non-linear chemistry in the atmosphere with significant impacts on human health, ecosystem and crop production. The spatial distributions of HCHO and NO2 are strongly correlated with emissions of VOCs and NOx, O3 precursors, therefore, a proxy ratio of HCHO/NO2 (FNR) can be an indicator to understand the O3 formation where VOC/NOx ratios are not available. Changes in meteorological conditions, such as wind speed and direction, temperature, and relative humidity can affect the spatial and temporal patterns of O3 and its precursors. The Aegean Region of Turkey with its geographical location, urbanization and industry, and vegetation and agriculture, experiences high O3 levels, given its high number of sunny days throughout the years. However, a comprehensive study in this regard has not been conducted in the region previously. The aim of this study is to investigate the spatial and temporal changes of O3 and to understand the O3 production regime and the relationship with its precursors in the southern Aegean Region.Within the study scope, ground-based NO2 and O3 measurements from the national monitoring network were used for understanding O3 pollution from 2019 to 2023. O3 and NOx (NO, NO2) are measured together at 33 air quality monitoring stations (AQMSs) in the Aegean Clean Air Region of Türkiye. 18% of the AQMSs exceeded EU limit for MDA8 O3 (maximum daily average 8-hr O3 >120 µg/m3, more than average of 25 days exceedance over recent 3 years) while almost 70% of the AQMSs exceeded World Health Organization (WHO) guidelines (>100 µg/m3 as MDA8 O3) in 2023. Manisa-Alasehir, Aydın-Efeler, and Izmir-Seferihisar AQMSs have consistently recorded the highest number of days, exceeding 100 days per year, according to the WHO guidelines. However, NO2 exceedances are limited in the AQMSs with O3 exceedances. Time series and pollution roses of O3 and NO2 were prepared to understand temporal changes along with meteorological parameters for stations with significant O3 problem. TROPOMI NO2 and HCHO retrievals within 6 km of AQMSs were processed, and FNR values were calculated for the same time period. O3 concentrations were examined by FNR values in order to explain O3 formation regimes. FNR values widely ranged in the region and the ozone season (May-September) average FNR values were estimated as 4.0https://doi.org/10.5194/egusphere-egu24-1526
Geochemical Implications for Tertiary Lower Crustal Melting in Northern Menderes Massif (Western Anatolia): Preliminary results
No full textTertiary migmatizations are pivotal events in the geologic history of the Menderes Massif, one of the world's most extensively studied core complexes. In northern Menderes Massif (Gördes Submassif) several granitic intrusions were emplaced into the migmatitic core rocks. They are mostly monzogranitic and granodioritic in composition and cut by associated pegmatitic dikes. These granitoids exhibit holocrystalline granular and porphyritic textures, characterized by plagioclase and, occasionally, biotite phenocrysts. The mineral composition of the granodiorites comprises 35–45% plagioclase, 30–35% quartz, 15–25% K-feldspar, and 5–10% biotite, with ± 5–8% muscovite. In contrast, the monzogranites are distinguished by a reduced plagioclase/K-feldspar ratio. Secondary phases include opaque minerals and sericite, with muscovite also observed. Accessory phases are zircon minerals. The granites exhibit an ASI index between 1 and 1.1, classifying them as slightly peraluminous I-type granites. They predominantly display high-K calc-alkaline characteristics and, less frequently, calc-alkaline nature. The Eu/Eu* ratio of these granites varies from 0.8 to 1.4. Trace element patterns suggest a possible derivation from basaltic and greywacke source rocks. Notably, high LaN/YbN ratios (reaching up to 107 ppm) and elevated Sr/Y ratios (up to 108 ppm) imply the presence of garnet or amphibole in the source. DyN/YbN and LaN/YbN ratios and their relationships specifically indicate the presence of garnet, rather than amphibole in the mafic source region. These data imply the crucial role of lower crustal melting in the formation of granitoids and the evolutionary history of the Menderes Core Complex.https://doi.org/10.5194/egusphere-egu24-901
A Hybrid Deep Learning and Optical Flow Framework for Monocular Capsule Endoscopy Localization
No full textPose estimation and localization within the gastrointestinal tract, particularly the small bowel, are crucial for invasive medical procedures. However, the task is challenging due to the complex anatomy, homogeneous textures, and limited distinguishable features. This study proposes a hybrid deep learning (DL) method combining Convolutional Neural Network (CNN)-based pose estimation and optical flow to address these challenges in a simulated small bowel environment. Initial pose estimation was used to assess the performance of simultaneous localization and mapping (SLAM) in such complex settings, using a custom endoscope prototype with a laser, micromotor, and miniaturized camera. The results showed limited feature detection and unreliable matches due to repetitive textures. To improve this issue, a hybrid CNN-based approach enhanced with Farneback optical flow was applied. Using consecutive images, three models were compared: Hybrid ResNet-50 with Farneback optical flow, ResNet-50, and NASNetLarge pretrained on ImageNet. The analysis showed that the hybrid model outperformed both ResNet-50 (0.39 cm) and NASNetLarge (1.46 cm), achieving the lowest RMSE of 0.03 cm, with feature-based SLAM failing to provide reliable results. The hybrid model also gained a competitive inference speed of 241.84 ms per frame, outperforming ResNet-50 (316.57 ms) and NASNetLarge (529.66 ms). To assess the impact of the optical flow choice, Lucas–Kanade was also implemented within the same framework and compared with the Farneback-based results. These results demonstrate that combining optical flow with ResNet-50 enhances pose estimation accuracy and stability, especially in textureless environments where traditional methods struggle. The proposed method offers a robust, real-time alternative to SLAM, with potential applications in clinical capsule endoscopy. The results are positioned as a proof-of-concept that highlights the feasibility and clinical potential of the proposed framework. Future work will extend the framework to real patient data and optimize for real-time hardware.https://doi.org/10.3390/electronics1418372
Geologic, Topographic, and Seismic Characteristics of Large Landslides Triggered by 2023 Kahramanmaras Earthquakes, Türkiye
No full textThe devastating Kahramanmaras earthquake sequence occurred on February 6, 2023. Two main events, Mw 7.8 and Mw 7.5, occurred 9 hours apart, affected 11 cities in Türkiye, and affected an area of ∼90,000 km2. This was the strongest historical earthquake doublet of magnitudes above 7.5 ever recorded in this region, and the consequences were catastrophic. The earthquake doublet triggered more than 3,600 landslides. Among these landslides, 35 of them have an area greater than 50,000 m2. Here, we focus on those largest coseismic landslides and show that 21 of them are pre-event landslides reactivated during the earthquake. They concentrate along a 5km-wide buffer zone around the surface rupture. Approximately 90% of these large landslides are distributed along the western section of the Eastern Taurus Mountain Belt, which is highly deformed and results in numerous overthrusts extending for 50 to 100 km. The geologic units in this part of the Taurus Mountain Belt consist of sedimentary, metamorphic, and igneous autochthonous and allochthonous units. The spatial distribution of landslides closely coincides with the topographic differences. They mostly (>82%) occurred on hillslopes where local relief varies between 500 and 700 m, and slope steepness ranges from 20° to 45°. Our preliminary analyses also revealed a relationship between the fault rupture dynamics and the distribution of large landslides. In addition to the rupture dynamics and topographic contrasts in the area, vertical lithological differences and the long-term tectonic deformations affecting autochthonous and allochthonous units have primary controls on the distribution of large landslides triggered by this earthquake doublet.https://doi.org/10.5194/egusphere-egu24-416
Decision Support System for Store Location Selection in Retailing
No full texthttps://doi.org/10.1007/978-3-031-83611-4_3
A Methodology Developed for Assessing the Potential Drivers of Water Losses in Natural Lakes at Country‐Scale: Status of Türkiye
No full textABSTRACT This study examines key features of natural lakes within a Lake Information Database (LID) and develops a lake assessment methodology (LAM) to identify the primary drivers of temporal water surface area (WSA) changes across Türkiye. The dominating driver for WSA changes is attributed either to natural factors or to human activities through harmonised analysis utilising LAM, which brings novelty to this study. Three lakes among the 27 with surface area over 2000 ha are displayed and discussed to show the applicability and performance of LAM that utilises remote sensing (RS) and geographical information system (GIS). The dominating factor on WSA decrease in the lakes was seen as climatic conditions in the higher altitude lakes, and human activities in the lower altitude lakes pointing out the key strength of the research. Thus, LAM offers a globally applicable and flexible methodology that produces fast results regarding the main drivers of WSA.https://doi.org/10.1111/wej.7000