IYTE GCRIS Database (Izmir Institute of Technology)
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Large-Area (50 Cm X 50 Cm) Optically Transparent Electromagnetic Interference (emi) Shielding of Zto/Ag an Analytical/Numerical and Experimental Study of Optoelectrical and Emi Shielding Properties
No full textTransparent conducting oxides (TCOs), exhibiting both high optical transparency and low electrical resistivity, are commonly employed in optoelectronic devices. However, acquiring a balance between these optical and electrical properties in a uniform way over large areas has been a pending challenge, which is essential to achieving optically transparent electromagnetic interference (EMI) shielding surfaces. In this study, we propose and demonstrate a stratified thin film structure consisting of zinc-doped tin oxide (Zn2SnO4, ZTO) as TCO along with a metal layer of silver (Ag) deposited on a large area of 50 cm x 50 cm polycarbonate (PC) substrate enabled by a scanning magnetron sputtering gun. We achieved high EMI shielding of 99.9% at the optical transparency of 68% in the visible spectrum by engineering the stratified architecture of ZTO/Ag/ZTO. The Ag layer of 18 nm in thickness with a sheet resistance of 10 Omega/sq yields shielding effectiveness (SE) of 27 dB in a wide frequency range of 2-20 GHz. The bottom and top ZTO layers, 20 and 40 nm thick, respectively, provide the lowest optical loss of 13% across 400-700 nm. The structure's EMI shielding, optical and structural performances were systematically characterized through a free-space focused-beam system, UV-Vis spectrophotometer, ellipsometry, focused ion-beam cross-sectional sampling and imaging, transmission electron microscopy, atomic force microscopy and secondary ion mass spectroscopy. EMI shielding and optical performances were validated by CST Microwave Studio and the transfer matrix method, respectively. These findings indicate that the proposed multi-layer architecture holds great promise for large-area EMI shielding and other optoelectronic applications
A Comprehensive Study on Doxorubicin-Loaded Aspartic Acid-Coated Magnetic Fesub>3/Sub>osub>4 Nanoparticles: Synthesis, Characterization and in Vitro Anticancer Investigations
No full textMagnetic Fe3O4 nanoparticles (MNPs) hold significant potential across various scientific fields due to their notable properties. For biomedical applications, MNPs must be biocompatible, stable, and possess high magnetic potential. Aspartic acid (ASP) as a coating agent not only provides biocompatibility, stability, and high magnetic potential but also offers the potential for absorbing various drugs for targeted delivery due to its carboxyl and amino functional groups. So, in this study, we synthesized ASP-coated MNPs (ASP-MNPs) through a one-step co-precipitation method and loaded doxorubicin (DOX) onto these nanoparticles to create DOX-ASP-MNPs for targeted drug delivery. Characterization of the nanoparticle confirmed the crystal structure, spherical morphology, and improved size distribution of ASP-MNPs (8.53 +/- 2.56 nm) compared to uncoated MNPs (7.05 +/- 1.89 nm), as analyzed by XRD, FESEM, and TEM. FT-IR and zeta potential assessments (ZP = -6.3 mV for MNPs, ZP = -31.1 mV for ASP-MNPs) verified successful ASP binding, DOX loading, and nanoparticle stability. VSM analysis indicated a slight decrease in saturation magnetism after coating (51.1 emu/g) compared to MNPs (57.4 emu/g). In vitro release studies demonstrated a higher release rate (83 %) of DOX-ASP-MNPs at pH 5.2, indicating their suitability for cancerous cells. Cytotoxicity assays on A-549 cancer cell lines showed a dose-dependent response. DAPI staining revealed that free DOX caused more DNA damage. Cellular uptake studies indicated a time-dependent uptake of DOX-ASP-MNPs, higher at 3 h compared to 1 h, though lower than free DOX uptake due to different uptake pathways. Apoptosis assays over 72 h showed similar apoptotic rates for DOX-ASP-MNPs and free DOX. These findings suggest that ASP-MNPs possess enhanced physicochemical properties and effective drug delivery capabilities, making them a promising candidate for different biomedical applications, particularly targeted cancer therapy
Combining Persona and Argument in Dialogue
No full textThe increasing popularity of personalized dialogue systems has gained momentum as people's desire for human-like interaction grows. This thesis aims to increase persona-consistent responses in personalized dialogue systems. A data augmentation method was used to enhance the persona consistency of dialogue systems. This technique utilized Large Language Models' few-shot learning capabilities to add counterfactual sentences to the dialogue. GPT 3.5 and Llama 2 models were used to generate counterfactual sentences using the few-shot prompting method. The augmentation method was applied to every dialogue in the PersonaChat dataset that did not originally contain a counterfactual sentence. Evaluation using the state-of-the-art personalized dialogue generation study showed that the persona-consistency results of the dataset augmented with the GPT 3.5 model showed better performance when assessed using metrics.İnsanların, insan benzeri konuşmalara ilgisinin artmasından dolayı son zamanlarda kişiselleştirilmiş diyalog sistemlerine olan ilgi artmaktadır. Bu sistemlerde kişilik bilgilerinin diyalog sistemlerine entegre olmasıyla beraber daha kişisel cevaplar sunulmaktadır. Bu tezde, kişiselleştirilmiş diyalog sistemlerindeki cevapların kişilik tutarlılığının artması amaçlanmıştır ve bu amaca yönelik veri büyütme yöntemi uygulanmıştır. İlgili yöntem ile karşı olgusal cümle içermeyen her diyaloğa karşı olgusal cümleler eklenmiş ve bu süreçte Büyük Dil Modellerinin (LLMs) az vuruşlu öğrenme yeteneklerinden yaralanılmıştır. Az vuruşlu öğrenme yöntemi ile karşı olgusal cümleler üretmek için GPT 3.5 ve Llama 2 modelleri seçilmiş olup, PersonaChat veri setinde karşı olgusal cümle içermeyen diyalogların her biri için veri artırma yöntemi uygulanmıştır. Metrikler ile yapılan değerlendirme sonucunda GPT 3.5 modeliyle zenginleştirilen veri setinin kişilik-tutarlılık sonuçlarının daha iyi olduğu gözlemlenmiştir
Corn Processing by Pulsed Electric Fields With Respect To Microbial Inactivation and Improvement of Seed Vigour
No full textPulsed electric field (PEF) treatment of corn grains to improve seed vigour and inactivation of endogenous microflora by energies ranging from 1.20 to 28.8 J were applied to determine effectiveness of applied energies on germination rate (GR), normal seedling rate (NSR), electrical conductivity (EC), ability to germinate under salt (100- and 200 mM salt) and cold (at 10 degrees C for 7 days and at 25 degrees C for 5 days) stresses. Moreover, the effect of PEF treatments was further investigated for the inactivation of total aerobic mesophilic bacteria (TAMB), total mold and yeast (TMY), and inactivation rate (%) of Aspergillus parasiticus. Increased energy provided 11.10 % increase in GR, 21.22 % increase in NSR, 95.50 % increase in germination at 10 degrees C for 7 days. Germination under stress conditions revealed 32.53 %, 68.35 %, and 76 % increase in germination at 25 degrees C for 5 days, under 100 mM- and 200 mM NaCI salt stresses. Inactivation on the mean initial TAMB and TMY were approximately 9.25 and 7.93 log, respectively, with 63.33 +/- 0.22 % reduction in A. parasiticus culture. PEF treated corn seedlings had stronger and taller body formation with stronger roots. The most optimal processing parameters were detected as 300 Hz, 28.80 J, and 19.78 sec. PEF treatment carries a high potential to improve corn vigour with inactivation of surface microflora
The Role of Hospital Morphology in Managing Wind Loads and Wind-Induced Building Motion in Healthcare Buildings
No full textThis thesis investigates the relationship between wind loads and inpatient tower morphologies and the architectural ramifications of this interplay with a particular emphasis on the impact of wind-induced building motion on occupant comfort. The formation of inpatient floors and the roof selection play a decisive role in shaping these morphologies. This thesis seeks to understand the relationship between different morphologies and the change in wind effect and its implications. To establish a foundation for wind analysis, various floor typologies were scrutinized, and hypothetical floor plans were developed. Using calculations based on EN1991-1-4 and ASCE 7-22 standards, the study investigates the wind loads through various inpatient floor layouts. The buildings were analyzed based on six different factors: inpatient floor plan, building orientation, height, roof type, roof slope, and exposure category. The calculations performed reveal differences between the codes. The building motions due to these wind loads are compared with the comfort limits given in the literature to examine the effects of the differences in the obtained results. The findings reveal significant differences in wind load calculations between codes regarding wind speed, building height, and assumptions about environmental conditions. In the building motion-human comfort analysis made depending on these differences, it was revealed that these differences caused the comfort limits of the building to be exceeded at different floor levels. Therefore, the study emphasizes the critical role of evaluating building safety and human comfort related to wind-induced motion perception under wind loads, underscoring the necessity for a nuanced understanding of different standards.Bu çalışma, rüzgar yükleri ile yataklı tedavi ünitelerinin morfolojileri arasındaki ilişkiyi ve bu etkileşimin mimari sonuçlarını, özellikle rüzgar kaynaklı bina hareketlerinin konfor üzerindeki etkisini vurgulayarak araştırmaktadır. Yataklı tedavi katlarının tasarımındaki farklı yaklaşımlar ve çatı seçimi, bu morfolojilerin şekillenmesinde belirleyici bir rol oynamaktadır. Hastane yapılarında yataklı tedavi ünitelerinin mekânsal düzenlemesi ve tasarımı, operasyonel verimlilik, hasta memnuniyeti ve sağlık hizmeti sonuçları üzerinde önemli etkilere sahiptir. Bu çalışma, farklı morfolojiler ile rüzgar etkisindeki değişimler arasındaki ilişkiyi ve bunun yansımalarını anlamayı amaçlamaktadır. Rüzgar analizi için bir temel oluşturmak adına, çeşitli kat tipolojileri incelenmiş ve varsayımsal kat planları geliştirilmiştir. EN1991-1-4 (2005) ve ASCE 7-22 (2022) standartlarına dayanan hesaplamalar kullanılarak, çeşitli yataklı tedavi kat plan düzenlemeleri üzerinden yapıya etki eden rüzgar yükleri incelenmiştir. Bu amaçla, binalar altı farklı faktöre göre analiz edilmiştir: yatan hasta kat planı, rüzgar yönü, bina yüksekliği, çatı tipi, çatı eğimi ve rüzgar maruziyet kategorisi. Hesaplamalar, standartlar arasındaki çevresel varsayımlara dayalı farklılıkları ortaya koymaktadır. Rüzgar etkilerine bağlı bina hareketleri, konfor sınırları ile karşılaştırılmıştır. Rüzgar kuvveti arttıkça, farkların da orantılı olarak arttığı ve farklı kat seviyelerinde konfor sınırlarının aşıldığı gözlemlenmiştir. Bu nedenle, rüzgar yükleri altındaki bina hareketlerinin, bina güvenliği ve insan konforu açısından değerlendirilmesi kritik öneme sahiptir. Çalışma, farklı standartların birlikte anlaşılmasının gerekliliğini vurgulamaktadır. Bu araştırma, yapısal bütünlüğü ve kullanıcı konforunu artırmak için yatan hasta birimi tasarımı konusunda değerli bilgiler sunmaktadır
İzmir’de Endüstri Mirası Olarak Halkapınar Su Pompa İstasyonu Binasının Korumaya Yönelik Değerlendirilmesi
No full textAvrupa’da 18. yüzyılda başlayan endüstri devriminin getirdiği modernleşmenin etkisiyle su dağıtımında yeni teknolojiler kullanılmıştır. Osmanlı Devleti de yabancı şirketlere tanıdığı imtiyazlarla bu gelişmelerden yararlanmıştır. İzmir’de “Compagnie Ottomane des Eaux de Smyrne” (İzmir Suları Osmanlı Şirketi), 1898 yılında Halkapınar Su Pompa İstasyonu Binasını inşa etmiştir. Günümüzde halen özgün işlevini sürdüren yapı, İzmir Su ve Kanalizasyon İdaresi’nin (İZSU), Halkapınar’da bulunan tesisi içinde yer alır. Yapı, günümüze kadar gelen endüstriyel mirasın nadir bir örneğidir ve 19. yüzyılda su dağıtımındaki teknolojik gelişmeyi yansıtması açısından önemlidir. Su Pompa İstasyonu, ana pompa binası ve iki müştemilattan oluşur. Bu çalışmanın amacı, yapının değerlerini ve sorunlarını analiz etmek ve bir koruma önerisi geliştirmektir. Çalışmanın yöntemi, yerinde yapılan incelemeler ve toplanan verilerin değerlendirilmesidir. Belirlenen sorunlar, zaman içinde yapılan niteliksiz ekler ve kaldırılan özgün elemanlardır. Çalışma sonucunda, yapının özgün işlevini sürdürmesi, ana pompa istasyonu binası ve müştemilatın özgün niteliklerinde yeniden düzenlenmesi ve halkın ziyaretine açılması önerilmiştir. Önerilen müdahaleler, yapının endüstriyel miras değerine katkı sağlayacaktır
Effect of Graphene Nanoplatelet Content on Mechanical and Elevated-Temperature Tribological Performance of Self-Lubricating Ze10 Magnesium Alloy Nanocomposites
No full textMagnesium (Mg) and graphene in alloy formulations are of paramount importance for lightweight engineering applications. In the present study, ZE10 Mg-alloy-based nanocomposites reinforced with graphene nanoplatelets (GNPs) having a thickness of 10–20 nm were fabricated via ultrasound-assisted stir casting. The effect of GNP contents (0.25, 0.5, and 1.0 wt.%) on the microstructure, Vickers hardness, and tensile properties of nanocomposites was investigated. Further, tribological studies were performed under a ball-on-disc sliding wear configuration against a bearing ball counterbody, at room and elevated temperatures of 100 °C and 200 °C, to comprehend temperature-induced wear mechanisms and friction evolution. It was revealed that the GNP addition resulted in grain coarsening and increased porosity rate of the Mg alloy. While the composites exhibited improved hardness by 20–35% at room temperature and 100 °C, a minor change was observed in their hardness and tensile yield strength values at 200 °C with respect to the GNP-free alloy. A notable improvement in lowering and stabilizing friction (coefficient of friction at 200 °C~0.25) and wear values was seen for the self-lubricating GNP-added composites at all sliding temperatures. The worn surface morphology indicated a simultaneous occurrence of abrasive and adhesive wear mode in all samples at room temperature and 100 °C, while delamination and smearing along with debris compaction (tribolayer protection) were the dominant mechanisms of wear at 200 °C. Inclusively, the results advocate steady frictional conditions, improved wear resistance, and favorable wear-protective mechanisms for the Mg alloy–GNP nanocomposites at room and elevated temperatures. © 2024 by the authors
Taylor Wavelets Collocation Technique for Solving Fractional Nonlinear Singular Pdes
No full textA novel technique has been introduced to solve the Emden–Fowler equations. It has been derived from the Taylor wavelets collocation method. The proposed scheme has been successfully implemented in order to solve the singular equations. The singular problem converts to a system of algebraic equations that can be solved numerically. Moreover, the technique is very effective to remove the strong singularity point at x=0. The numerical experiments have been checked out with the exact and approximate solutions that have been achieved by others including the Adomian decomposition method (Wazwaz in Appl Math Comput 166:638–651, 2005), Modified Homotopy Perturbation Method (Singh et al. J Math Chem 54(4):918–931, 2016). Also, the error analysis of the technique has been considered. © The Author(s), under exclusive licence to Islamic Azad University 2022
Outage Probability Analysis of Triple-Hybrid Rf/Fso Communication System
No full textTerahertz (THz) and free space optical (FSO) transmission techniques are considered as alternatives for radio frequency (RF) transmission to meet the requirements for the sixth generation and beyond wireless communication systems. However, these transmission techniques may experience high level of deterioration under different weather conditions. In this study, triple-hybrid RF/FSO/THz system is proposed to enhance the system performance. The results have shown that the proposed system has improved outage probability performance under wide range weather conditions compared to only RF, only FSO, and only THz systems as well as dual-hybrid systems (RF/FSO, RF/THz, and FSO/THz). Theoretical results are validated via computer simulations
Linear Wave Interaction by Multiple Vertical Cylinders of Non-Circular Smooth Cross-Section: an Iterative-Asymptotic Approach
No full textThe three-dimensional problem of water wave diffraction by multiple cylinders of non-circular smooth cross-sections is studied. The rigid cylinders extend from the sea bottom to the free surface in water of finite depth. The flow is described by the linear theory of potential flow. A fourth-order asymptotic solution of the diffraction problem by a single cylinder with the asymptotic parameter being the closeness of the cross-section to a circle is combined with an iterative method to consider the effect of the wave interaction between the cylinders. The original problem for non-circular cylinders is reduced to a set of diffraction and radiation problems for circular cylinders at each asymptotic order. The velocity potentials are given by their Fourier series, and the problem solving is simplified to the algebraic operations involving the Fourier coefficients of the potentials and the shape function, which describes the cross-sectional shape of the vertical cylinder. The hydrodynamic forces and wave run-up values for geometries of two elliptical and four nearly square cylinders are presented for a range of incident wave frequencies and angles of attack. The method is validated by comparing the present hydrodynamic force results with the ones in the literature, and good agreement is reported. © 2024 Elsevier Lt