IYTE GCRIS Database (Izmir Institute of Technology)
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A Holistic Overview of the Applications of Grace-Observed Terrestrial Water Storage in Hydrology and Climate Science
No full textTerrestrial Water Storage (TWS) represents a vital element of the hydrological cycle, with its fluctuations significantly impacting the climate of the Earth and its ecological balance. Since its launch in 2002, the Gravity Recovery and Climate Experiment (GRACE) satellite mission has revolutionized the ability to observe and analyze large-scale mass changes within Earth's system components. This paper offers a comprehensive and current overview of GRACE satellite gravimetry, highlighting its relevance to hydrological and climate-related studies. It outlines the fundamental measurement principles of the GRACE mission, provides an in-depth explanation of GRACE data products (including spherical harmonic and mascon solutions), examines emerging trends in GRACE-based research, and reviews key applications in hydrology and climate science. Additionally, it addresses the major challenges in utilizing GRACE data and explores promising avenues for future research and applications
Araştırmacıları güçlendirmek: telif hakkını korumak ve açık erişim yayıncılıkta etkinizi en üst düzeye çıkarmak
No full textPATTERN Projesi kapsamında 21 Nisan 2025 ve 30 Nisan 2025 tarihlerinde online olarak gerçekleştirilen "Araştırmacıları güçlendirmek: telif hakkını korumak ve açık erişim yayıncılıkta etkinizi en üst düzeye çıkarmak" başlıklı eğitime ait sunumdur
Time-Dependent Effects of Low-Intensity Pulsed Ultrasound on Apoptosis and Autophagy in Malignant Melanoma Stem Cells
No full textCancer stem cells (CSCs) in malignant melanoma contribute to therapeutic resistance and tumour recurrence. While low-intensity pulsed ultrasound (LIPUS) has been proposed as a non-invasive strategy to induce cell death, its effects on CSC-specific apoptotic and autophagic responses remain unclear. This study aimed to explore the time-dependent effects of LIPUS on apoptosis and autophagy in CD133+ melanoma CSCs and CD133- non-stem melanoma cells. Human melanoma cells (CHL-1) were sorted via FACS into CD133+ and CD133- populations. Cells were exposed to LIPUS (1 MHz, 20% duty cycle, 1 W/cm2) for 1, 5, and 10 min. Protein expression levels of Caspase-3, Caspase-8, mTOR, and LC3 were evaluated via immunofluorescence and quantified by image-based analysis. Both cell populations showed significant increases in Casp3, Casp8, mTOR, and LC3 intensities following LIPUS application. Notably, CD133+ cells exhibited delayed but sustained increases in Casp3 and LC3 expression, while CD133- cells responded more rapidly. mTOR activity demonstrated distinct temporal dynamics between the two groups, suggesting differential modulation of autophagy-related pathways. LIPUS triggers temporally distinct apoptotic and autophagic responses in melanoma CSCs and non-stem cancer cells. These findings suggest a potential therapeutic avenue to selectively disrupt CSC survival mechanisms using mechanical stimulation
Recognition of Counterfactual Statements in Turkish
No full textCounterfactual statements are examples of causal reasoning as they describe events that did not happen and, optionally, those events' consequences if they happened. SemEval-2020 introduces the counterfactual detection (CFD) task and shares an English dataset. Since then, a set of datasets has been released in English, German, and Japanese as part of Amazon product reviews. This work releases the first Turkish corpus of counterfactuals (TRCD). The data collection process is driven by a clue phrase list of counterfactuals, mainly in the form of verb inflections in Turkish. We use clue phrase-based filtering to collect sentences from the Turkish National Corpus (TNC). On the other hand, half of the collection is subject to random word filtering to avoid selection bias due to clue phrases. After the human annotation process with an Inter Annotator Agreement of 0.65, we have 5000 sentences, of which 12.8% contain counterfactual statements. Furthermore, we provide a comprehensive baseline of transformer-based models by testing the effect of clue phrases, cross-lingual performance comparisons using the available CFD datasets, and zero-shot cross-lingual classification experiments using fine-tuning on the different combinations of the existing datasets. The results confirm that TRCD is compatible with the other CFD datasets. Moreover, fine-tuning a Turkish-specific model (BERTurk) performs better than the multilingual alternatives (mBERT and XLM-R). BERTurk is more robust to clue phrase masking. This result emphasizes the importance of a language-specific tokenizer for contextual understanding, especially for low-resource languages. Finally, our qualitative analysis gives insights into errors by different models
Durable ZrB2–ZrC Composite Materials as Advanced Electrodes for High-Performance Supercapacitors
No full textBoride and carbide-based materials attract increasing attention as promising options for energy storage applications. This research focuses on synthesizing pure boride and carbide compounds of zirconium (ZrB2 and ZrC) and their composite powders using mechanical activation-assisted route and subsequent heating processes. The chemical and microstructural characterization results indicate that the synthesized composite powders are of high purity, possess submicron-scale particle sizes (below 400 nm), and exhibit a high surface area of up to 9.41 m2/g. Supercapacitor devices, using the resulting powders as symmetrical electrodes, exhibit high energy density values ranging from 5.8 to 8.8 Wh/kg. The ZrB2-15 wt % ZrC composite sample achieves the highest power density at 155 W/kg, compared to 118 W/kg for the pure ZrB2 sample. Cycling tests demonstrate exceptional capacitance retention (99.4-99.9%) and cyclic stability, even after 5000 cycles, highlighting the high durability of the composite samples. These findings show that ZrB2-ZrC composites exhibit high energy and power density values and excellent cycling performance, making them strong candidates for use in high-performance supercapacitor devices
Automated Deep Learning Model Development Based on Weight Sensitivity and Model Selection Statistics
No full textCurrent sustainable production and consumption processes call for technological integration with the realm of computational modeling especially in the form of sophisticated data-driven architectures. Advanced mathematical formulations are essential for deep learning approach to account for revealing patterns under nonlinear and complex interactions to enable better prediction capabilities for subsequent optimization and control tasks. Bayesian Information Criterion and Akaike Information Criterion are introduced as additional constraints to a mixed-integer training problem which employs a parameter sensitivity related objective function, unlike traditional methods which minimize the training error under fixed architecture. The resulting comprehensive optimization formulation is flexible as a simultaneous approach is introduced through algorithmic differentiation to benefit from advanced solvers to handle computational challenges and theoretical issues. Proposed formulation delivers 40% reduction, in architecture with high accuracy. The performance of the approach is compared to fully connected traditional methods on two different case studies from large scale chemical plants
Lithiated Single-Layer Holey Mo8s12: Electronic, Magnetic and Vibrational Characteristics
No full textMotivated by the recent experimental realization of holey transition metal chalcogenides[ACS Applied Materials ; Interfaces 2022, 14(23), 27056-27062], in this study, the holey structure of Mo8S12 is investigated by means of density functional theory-based calculations. The geometry optimization and phonon band dispersion calculations show the structural and dynamical stability of free-standing holey single-layer Mo8S12. In addition, electronic band dispersions reveal the direct band gap semiconducting nature of the structure. In order to investigate the lithiation capacity of single-layer Mo8S12, effect of Li doping on the properties of Mo8S12 is analyzed by considering both one- and double-sided lithiation. Our calculations indicate that single Li atom is chemically adsorbed on top of Mo8S12 through the Mo-Mo bridge site and experiences relatively high diffusion barrier at room temperature, which shows the chemical stability of adsorbed Lion the surface. As one surface of single-layer Mo8S12 is fully saturated with Li atoms, a dynamically stable semiconducting structure is formed. Moreover, the double-side lithiated structure is found to be dynamically stable derivative of Mo8S12. The corresponding electronic band structures reveals the semiconducting behavior of the double-side lithiated single-layer. The predicted voltage of lithiated Mo8S12 reveal its potential for battery applications as a cathode material. Apparently, either one or two side lithiation allows one to significantly tune the electronic and magnetic properties of Mo8S12. Overall, tunable electronic band gap of single-layer holey Mo8S12 via lithiation could make it suitable candidate for optoelectronic devices
Exploring Geothermal Energy Based Systems: Review From Basics To Smart Systems
No full textMost of the energy demand is currently supplied from fossil fuels, which leads to the accumulation of greenhouse gases and air pollution. A sustainable future can be created globally through the efficient use of renewable energy sources. These sources include wind, solar, geothermal, biomass, and more. Geothermal energy can meet the energy needs of the future as a clean and reliable source and stands out due to certain distinctive features among renewable energy sources. Unlike other renewable energy sources, geothermal energy is not dependent on time or weather, making it a reliable and continuous energy supply. Additionally, it has a lower environmental impact. This review examines the development of geothermal energy systems and their integration into smart technologies, highlighting the potential of geothermal energy for smart energy systems. The focus is on integrating smart systems into geothermal-based setups to enhance efficiency and analyze the state-of-the-art technologies of such systems. Geothermal-based systems can be classified as single generation, co-generation, multigeneration, smart energy systems, and energy hubs. Consequent to examining systems, it has been concluded that geothermal systems have a huge potential, but unfortunately, not all of them are used due to some difficulties. Its development will occur faster, and its share in the renewable energy sector will grow with smart system integration
Regenerable Nickel Catalysts Strengthened Against H2s Poisoning in Dry Reforming of Methane
No full textIn this study, alumina-supported bimetallic Ni-Cu and trimetallic Ni-Cu-Ce catalysts were synthesized to improve catalysts resistant to coke formation and sulfur poisoning for dry reforming of methane (DRM). The effects of parameters such as feed composition, synthesis method, and H2S concentration using the catalyst with the best activity were also investigated. To determine the physical and chemical properties of the synthesized catalysts, XRD, N2 adsorption-desorption, TGA-DTA, ICP-OES, SEM-EDX, XPS, and DRIFTS analyses were performed. XRD analysis showed that the fresh Ni-Cu catalysts have elemental nickel and gamma- alumina phases in their structures. In addition to these structures, the CeO2 crystal structure was determined for the Ni-Cu-Ce catalyst. Type IV isotherm with H1 hysteresis indicating uniform mesoporous structure was obtained with all the catalysts. The activities of the synthesized catalysts in DRM were performed in the presence of different concentrations of H2S (2 ppm, 50 ppm, and 500 ppm) in a fixed bed reactor at 750 degrees C using a gas chromatography-equipped system. The alumina-supported 8Ni-3Cu-8Ce catalyst prepared by the impregnation method exhibited a higher and more stable activity comparing the bimetallic Ni-Cu catalyst in the presence of H2S. Adding copper and cerium to the nickel catalyst has a curative effect on resistance to coke formation and sulfur poisoning. Excess CO2 in the feed stream increased the H2S poisoning resistance of the catalyst. To analyze the reactor exit stream in catalytic activity using different feed stream compositions such as H2S+He, H2S+CO2+He, and H2S+CO2+CH4+He, FTIR with a gas cell was used. The formation of carbonyl sulfide (COS) and H2O, which occurs due to the possible reaction between CO2 and H2S, was observed. Regeneration studies showed that the catalyst could undergo regeneration with a low oxygen concentration (0.3 % O2 in He). 8Ni-3Cu-8Ce@SGA, which gave 71 % CH4 conversion in the first minute of the reaction test in the presence of 50 ppm H2S, was regenerated after completely losing its activity at the end of 5 h. 66 % CH4 conversion was achieved when tested again in the absence of H2S (CH4/CO2/Ar:1/1/1). The 8Ni-3Cu-8Ce@SGA catalyst was deemed worthy of investigation for industrial applications
Sleep Quality: Design of Bedroom Ventilation and Evaluation Within the Scope of Current Standards
No full textIndoor air pollution is one of the leading environmental risks to public health considering people now spending nearly 90 % of their day in indoor environments. A significant portion of this time indoors is devoted to sleeping, making it crucial to address the impact of indoor environmental conditions on sleep quality. International ventilation standards such as ASHRAE and CEN, as well as country-specific guidelines, offer valuable recommendations for ventilation design in residential buildings, including bedrooms. This study aims to evaluate the importance of determining ventilation rates in sleeping spaces using Indoor Air Quality Procedure (IAQP) compared to Ventilation Rate Procedure (VRP) in accordance with current standards. Here, the IAQP approach for determining air flow rate is based on the CO2 balance by maintaining CO2 levels in any sleeping environment below specified upper limits of 750 ppm and 1000 ppm. This study focused on the adult population, which forms the majority of society, with analyses conducted for both single and double occupancy sleeping conditions. The volume of environment where ventilation is not required during sleep (Vf) is inaccessible in conventional sleeping environments (10-21.6 m3 per person). Therefore, proper ventilation is of great importance for any sleeping space that is smaller than the Vf. The results of the analyses show that for the conventional sleeping volumes, CO2 levels reach 750 ppm (upper limit for comfortable sleep) in the first hour and increase to the disturbed sleep zone in about 2 h. Additionally, a chart outlining the necessary ventilation flow rates is suggested for maintaining maximum CO2 concentrations of 750 and 1000 ppm during different sleep durations and in various sleeping environments with varying volumes. Finally, the ventilation rates determined based on unit area and/or occupancy levels in standards (referred to as VRP) may not always be adequate or may be excessive in order to maintain CO2 concentrations below the recommended limits of 750 and 1000 ppm. It is advised to utilize demand-controlled ventilation by considering the system design as recommended by IAQP