IYTE GCRIS Database (Izmir Institute of Technology)
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Application of Fractional Calculus-Based Anomalous Diffusion Model for Drying Analysis of Large Grapes Subjected To Micro-Perforation Pretreatment
No full textThe study aimed to assess the potential of using needle micro-perforation pretreatment at various piercing lengths as an alternative to dipping in alkaline liquor solution for the hot air drying process of large grapes at temperatures of 60, 70, and 80 degrees C. Fick's second law and anomalous diffusion model based on the fractional calculus approach were used to analyze the drying curves and estimate effective diffusivity (D-eff). Needle micro-perforation on drying kinetics and some physicochemical properties (water activity, pH, titratable acidity, rehydration rate, shrinkage ratio, and color) of hot air dried Kavacik grapes (Vitis vinifera L. cv Alphonse Lavall ; eacute;e) were investigated. The anomalous diffusion model fit the experimental data better and revealed super-diffusive behavior (alpha > 1). The effective diffusivity coefficients varied between 1.00 x 10(-10) to 6.47 x 10(-10) m(2)/s. The pretreatment at various piercing lengths showed no significant impact on water activity and color (P > 0.05). However, it did have a significant effect on pH, titratable acidity, rehydration rate, and shrinkage degree (P 0.05). MG1.5 drying conditions at 60 degrees C were found to be the most suitable process conditions for achieving energy-efficient drying (high D-eff: 3.87 x 10(-10) m(2)/s) of grapes while preserving their highest-quality attributes related to drying (a(w): 0.54, RR: 1.95, pH: 4.31, Delta E: 3.38 and SR: 0.98). The results revealed that the needle micro-perforation pretreatment provided better color and water activity properties in dried grapes, and the drying time was reduced at even low temperatures. It has been shown that micro-perforation can be an environmentally friendly alternative method to chemical pretreatment in grape drying
The Role of Trna Fragments on Neurogenesis Alteration by H2o2-Induced Oxidative Stress
No full textTransfer RNAs (tRNAs) are small non-coding RNA molecules transcribed from tRNA genes. tRNAs cleaved into a diverse population tRNA fragments (tRFs) ranging in length from 18 to 40 nucleotides, they interact with RNA binding proteins and influence the stability and translation. Stress is one of the reasons for tRFs cleavage. In our study, we modeled oxidative stress conditions with hydrogen peroxide (H2O2) exposure and dealt with one of the frequently expressed tRF in the hippocampus region of the brain, which is tRF-Glu-CTC. For this purpose, neural stem cells (NSCs) were exposed to H2O2, and tRF-Glu-CTC levels were increased in various H(2)O(2 )concentrations. A decrease was seen in microtubule-associated protein 2 (MAP2) marker expression. To understand the H(2)O(2)oxidative stress condition on the expression of tRNA fragments, 72 hpf zebrafish embryos exposed to different H(2)O(2 )concentrations, an increase in the level of tRF-Glu-CTC was observed in all concentrations of H(2)O(2 )compared to control. Subsequently, neurogenesis markers were figured out via Calb2a (calbindin 2a) in situ hybridization (ISH) and HuC/D immunofluorescence staining (IF) staining experiments. Under H(2)O(2 )exposure, a decline was observed in Calb2a and HuC/D markers. To understand the inhibitory role of tRF-Glu-CTC on neurogenesis, NSCs were transfected via tRF-Glu-CTC inhibitor, and neurogenesis markers (ss III-tubulin, MAP2, and GFAP) were determined with qRT-PCR and IF staining. tRF-Glu-CTC inhibitor reversed the diminished neuronal markers expression under the exposure of H2O2. Gene Ontology (GO) enrichment analysis showed us that targets of tRF-Glu-CTC are generally related to neuronal function and synaptic processes
Surface Modification Via Alkali Treatment and Its Effect on the Physicochemical and Biological Properties of Emulsion Templated Scaffolds
No full textEmulsion templating is an advantageous scaffold fabrication technique that provides high interconnectivity, high porosity, and control of the scaffold architecture. Polymerised emulsions with an internal phase ratio greater than 74 % are named Polymerised High Internal Phase Emulsions (PolyHIPEs). Polycaprolactone (PCL) is a synthetic, biodegradable, and biocompatible polymer widely used in tissue engineering, but the material-cell interaction of PCL-based biomaterials has been found to be limited due to the material's high hydrophobicity. This study aims to develop emulsion-templated polycaprolactone tetramethacrylate (4PCLMA)-based scaffolds and improve their biological performance using an alkaline surface modification method. For this purpose, 4PCLMA was successfully synthesised, and highly porous scaffolds were developed. PolyHIPEs were incubated in three different sodium hydroxide (NaOH) concentrations for three different incubation times. Chemical, morphological, mechanical characterisation, mass loss, water absorption capacity, water contact angle, Brunauer-Emmett-Teller analyses and biological investigations were conducted on NaOH-treated scaffolds in comparison with the control. The chemical changes induced by NaOH treatment in PolyHIPEs were confirmed by Fourier-transform infrared spectroscopy. NaOH treatment increased the water absorption capacity, hydrophilicity, surface area, and protein adsorption but decreased the weight and mechanical strength of the scaffolds. In vitro results showed that NaOH treatment did not cause cytotoxicity in L929 cells and positively affected the cell adhesion and proliferation behaviour of Saos-2 cells. This study suggests surface modification of biodegradable synthetic polymer-based PolyHIPEs by NaOH treatment as a simple, scalable and cost-effective approach to enhance cell-material interactions of the material without causing a significant change in the overall morphology, contributing to the advancement of next-generation healthcare technologies
Demystifying Power and Performance Variations in Gpu Systems Through Microarchitectural Analysis
No full textGraphics Processing Units (GPUs) serve efficient parallel execution for general-purpose computations at high-performance computing and embedded systems. While performance concerns guide the main optimization efforts, power issues become significant for energy-efficient and sustainable GPU executions. Profilers and simulators report statistics about the target execution; however, they either present only performance metrics in a coarse kernel function level or lack visualization support that can enable microarchitectural performance analysis or performance-power consumption comparison. Evaluating runtime performance and power consumption dynamically across GPU components enables a comprehensive tradeoff analysis for GPU architects and software developers. In this work, we present a novel memory performance and power monitoring tool for GPU programs, GPPRMon, which performs a systematic metric collection and provides useful visualization views to guide power and performance analysis for target executions. Our simulation-based framework dynamically gathers SM and memory-related microarchitectural metrics by monitoring individual instructions and reports dynamic performance and power values. Our interface presents spatial and temporal views of the execution. While the first demonstrates the performance and power metrics across GPU memory components, the latter shows the corresponding information at the instruction granularity in a timeline. We demonstrate performance and power analysis for memory-bound graph applications and resource-critical embedded programs from GPU benchmark suites. Our case studies reveal potential usages of our tool in memory-bound kernel identification, performance bottleneck analysis of a memory-intensive workload, performance-power evaluation of an embedded application, and the impact of input size on the memory structures of an embedded system
Comments on “Relaxed Conditions for the Input-to-State Stability of Switched Nonlinear Time-Varying Systems”
No full textThis study addresses the deficiencies in the assumptions of the results in (Chen and Yang, 2017) due to the lack of uniformity. We first show the missing hypothesis by presenting a counterexample. Then, we prove why they are wrong in that form and show the errors in the proof of the main result of (Chen and Yang, 2017). Next, we compare the assumptions and related results of (Chen and Yang, 2017) with similar works in the literature. Lastly, we give suggestions to complement the shortcomings of the hypotheses and thus correct them
Fabrication and Characterization of Ni-based Electrodes for Improved NiZn Battery Performance
No full textBu çalışmada, nikel-çinko (NiZn) bataryasında nikel elektrot olarak kullanılmak üzere aktif malzeme olan nikel hidroksit (Ni(OH)2) tozlarını sentezlemek için hidrotermal yöntem kullanılmıştır. Hazırlanan Ni elektrotlardaki katot malzemesini karakterize etmek için X-ışını kırınımı (XRD), taramalı elektron mikroskobu (SEM), zeta potansiyeli, Brunauer-Emmett-Teller (BET) ve elektrokimyasal performans testleri kullanılmıştır. Sonuçlar, kristal yapıya sahip β-fazlı nano boyutta küresel Ni(OH)2 partiküllerin sentezlendiğini göstermiştir. Elektrokimyasal test sonuçları ise Ni elektrodun yarı hücrede kararlı bir çevrim döngüsüne sahip olduğunu göstermiştir. Elektrokimyasal performans sonuçlarına göre, sentez sıcaklığı 70oC olan ve sentez sonrası 3 saat boyunca bekletildikten sonra elde edilen Ni(OH)2 tozları ile hazırlanan Ni elektrot (Ni_pH12_3h_70oC) en iyi performans gösteren metal hidroksit olmuştur. Nikel elektrotlar birbiriyle karşılaştırıldığında, NiCoZn elektrot yüksek OER (oksijen evrim reaksiyonu) ve ORR (oksijen indirgeme reaksiyonu) aktiviteleri sergilemiştir, çünkü kobalt ve çinko oksitlerin nikel ile kombinasyonu mükemmel elektrolit erişim kabiliyeti ve aktif malzeme boyunca etkili iyon transferi sağlamaktadır. NiZn batarya içerisinde kullanılan NiCoZn elektrotu 10 mA cm-2 akım yoğunluğunda 192,7 mAh gaktif-1 değere ulaşarak yüksek bir kapasite ve kararlı bir çevrim döngüsü (10 mA cm-2'de 70 çevrim döngüsü sonucunda) sergilemiştir. NiCoZn elektrodu Ni, Co ve Zn arasındaki mükemmel etkileşmi ile, yüksek başlangıç potansiyeli ve akım yoğunluğu sergilemiş; bu da NiCoZn elektrotun NiZn bataryalardaki Ni-tabanlı elektrotlar için yüksek performanslı bir konfigürasyon olarak umut verici bir aday olduğunu göstermiştir
Byzantine Wall Paintings in the Archaeological Sites of Aigai, Olympos, and Anaia (Turkey): Techniques and Material Characteristics
No full textThe aim of this study is to determine the material characteristics of the paint layers and techniques of paintings executed in Late Roman and Byzantine churches located in the archaeological sites of Aigai, Olympos, and Anaia (Turkey) in order to select compatible materials prior to conservation treatments of the paintings and to establish the technical aspects of the paintings in relation to coeval Western examples. In this context, the execution technique, microchemical characteristics, stratigraphy of paintings, and mineralogical and chemical composition of the pigments were determined by polarized light microscopy (PLM), scanning electron microscopy coupled with X-ray energy dispersive spectroscopy (SEM-EDX), and Fourier transform infrared spectroscopy (FTIR). The analysis results indicated that wall paintings were executed by fresco, secco or fresco-secco techniques on a thin plaster layer that is composed of pure lime, straw, fine marble, brick, and sand aggregates. The ground layers of the paintings are composed of kaolin, calcite, and carbon black. The color compositions of the paintings were obtained by applying successive layers of paint on the ground layers. The pigments used in the paintings are mainly iron oxides for the red and yellow, green earth in celadonite and glauconite forms for greens, and lapis lazuli and Egyptian blue for blues. The present study demonstrates that the techniques and materials employed in the execution of wall paintings in Byzantine churches in Western Anatolia are analogous to those utilized in the Balkans, Crete, and Cyprus, with the exception of the presence of a clay-based ground
Co-Pyrolysis of Waste Wind Turbine Blades in a Molten Polyolefin Medium
No full textThis study investigates the pyrolysis and co-pyrolysis processes of waste wind turbine blades (WWTB) and polyolefins (POs) at 450 degrees C in a round bottom tank reactor. The study contains three experimental sets: 1) batch pyrolysis of POs; 2) continuous pyrolysis of WWTB; 3) continuous feeding of WWTB into a molten PO medium, which was previously fed to the round bottom tank reactor batch-wise. Individual WWTB pyrolysis yields a modest 18.7 wt% of liquid, predominantly influenced by elevated ash and fixed carbon content. Conversely, copyrolysis demonstrates positive synergies, with escalating polyolefin content boosting liquid yields, reaching a peak at 61.5 wt% with a WWTB:POs mixture (25:75, wt%), while concurrently suppressing gas production to 21.6 wt%. The primary chemical groups found in the liquid obtained from WWTB are phenol and phenolic compounds, with their abundance diminishing as the POs ratio in feedstocks increases. Analysis of noncondensable gases from WWTB reveals that approximately 57.7 wt% are oxygen-containing, predominantly CO and CO2. Co-pyrolysis with POs at a 25:75 (wt%) ratio yields 47.1 wt% C3H6, resembling POs pyrolysis. The resulting solid products are rich in carbon and contains high ash. This research not only offers a detailed product analysis of WWTB but also sheds light on the dynamics of its co-pyrolysis with POs. Doing so contributes crucial insights into the transformative potential of pyrolysis and co-pyrolysis processes, covering the way for sustainable waste-to-resource solutions
Impact of Cooling Strategies and Cell Housing Materials on Lithium-Ion Battery Thermal Management Performance
No full textThe transition to renewable energy sources from fossil fuels requires that the harvested energy be stored because of the intermittent nature of renewable sources. Thus, lithium-ion batteries have become a widely utilized power source in both daily life and industrial applications due to their high power output and long lifetime. In order to ensure the safe operation of these batteries at their desired power and capacities, it is crucial to implement a thermal management system (TMS) that effectively controls battery temperature. In this study, the thermal performance of a 1S14P lithium-ion battery module composed of cylindrical 18650 cells was compared for distinct cases of natural convection (no cooling), forced air convection, and phase change material (PCM) cooling. During the tests, the greatest temperatures were reached at a 2C discharge rate; the maximum module temperature reached was 55.4 degrees C under the natural convection condition, whereas forced air convection and PCM cooling reduced the maximum module temperature to 46.1 degrees C and 52.3 degrees C, respectively. In addition, contacting the battery module with an aluminum mass without using an active cooling element reduced the temperature to 53.4 degrees C. The polyamide battery housing (holder) used in the module limited the cooling performance. Thus, simulations on alternative materials document how the cooling efficiency can be increased
Therapeutic and Pharmaceutical Applications of Pegylated Nano-Carriers
No full textThe coating of the exterior of nanocarriers with polyethylene glycol (PEG; known as “PEGylation”), has emerged as one of the most widely adopted approaches to impart stealth properties to pharmaceutical nanocarrier systems. The PEGylation tactic offers a stealth barrier towards the adsorption of circulatory proteins owing to its hydrophilicity, elasticity, neutralization, and hydration properties. PEGylation dramatically provides sustained drug release benefits, reduces immune sensitivity, as well as improves the systemic circulation period, Overall, PEGylation effectively improves the therapeutic efficacy of the loaded therapeutic moiety in treating target cells and tissues. This chapter offers discussion on drug delivery nanosystems that are developed based on the principle of PEGylation strategy. Furthermore, a detailed account of the pharmaceutical and biomedical applications of PEGylated nanocarriers has also been presented in detail. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024