Istanbul Technical University
Ulusal Üniversitelerarası Açık Erişim Sistemi - İstanbul Teknik ÜniversitesiNot a member yet
67356 research outputs found
Sort by
Polymer-water partition coefficients of butyl rubber and polydimethylsiloxane passive samplers for polycyclic aromatic hydrocarbons using the co-solvent method
No full texthttps://doi.org/10.1007/s11356-025-36971-
Imaging the Electrical Resistivity Structure of a Locked Fault Segment: The Ganos Fault example
No full textThe Ganos Fault, in the westernmost part of the North Anatolian Fault Zone (NAFZ), stayed quiet for approximately 146 years before two catastrophic events shook the area in the summer of 1912. The historical records point out that two devastating activities shook both sides of the Marmara Sea in 1766, too. Following the 1766 events, on August 9th, 1912, two blocks of the dextral Ganos Fault shifted one more time to create an Mw = 7.4 event near Mürefte in Tekirdağ. Nearly a month later, further to the west, the fault zone moved on September 13th, forcing another disastrous Mw= 6.8 earthquake. Almost 112 years have passed since then (leaving approximately 34 more years to complete the recurrence), and the Ganos Fault is again acting as a seismic gap. In brief, the Ganos Fault tends to generate another series of earthquakes in the region, and the fault zone characteristics of this locked segment are poorly known. In this study, magnetotellurics (MT) method is utilized to image the crustal electrical resistivity structure for deciphering the fault zone geometry. With this object in mind, simultaneous electric and magnetic observations were made at nearly 40 sites in two campaigns. For each observation point, the collected data were transferred to the frequency domain where the electromagnetic impedance tensor elements were calculated with robust processing algorithms (Birrp) for wideband frequencies. Following the dimensionality analyses performed with various tools such as Groom and Bailey decomposition, phase tensor analysis, etc., which eventually pointed out a geo-electric strike angle of nearly ~N60oE, numerical models based on two- and three-dimensional algorithms (such as MT2D and ModEM) were developed to image the fault zone properties of the Ganos Fault. Several numerical models were calculated to realize the influence of the coast-effect caused by the Marmara Sea. Pre-modeling analysis results and the final models suggest that (i) the geo-electric strike angle of ~N60oE agrees well with the earlier results, the geology and the fault’s geometry, (ii) the Ganos Fault acts as a geological boundary between the Eocene-aged Keşan Formation in the north and Miocene-aged Çengelli Formation in the south, (iii) while the Keşan Formation defines a continuous tubular highly resistive zone (~500- 800 Ωm) that may be acting as the seismogenic zone along the Ganos Fault, the Çengelli Formation appears to be less resistive in coherent with the ages of the formations highlighted earlier, (iv) the aforementioned resistive block reaches to a depth of nearly 15 - 18 km and this feature may mark the bottom of the seismogenic zone.          https://doi.org/10.5194/egusphere-egu24-1534
Hydrogen Embrittlement in Tungsten Arises from Grain Boundary Degradation Despite Bulk Resistance
No full texthttps://doi.org/10.2139/ssrn.5332934https://doi.org/10.2139/ssrn.550256
A Simulation-Based Solution for Queue Problems at Construction Sites Under Unusual Conditions: Case Analysis on Integrating Digital Technologies into Daily Construction Activities
No full texthttps://doi.org/10.22541/au.174717568.82761164/v
Otonom Sürüş için Çok-kategorili Kalabalık Analizi Multi-category Crowd Analysis for Autonomous Driving
No full texthttps://doi.org/10.1109/siu66497.2025.1111180
Strength and Deformability of FRP-Jacketed Large-Size Concrete Cylinders after Exposure to Long-Term Actual Environmental Effects
No full texthttps://doi.org/10.1061/jccof2.cceng-451
Effects of periodic potentials on the non-hermitian fermionic superfluidity
No full textTez (Yüksek Lisans)-- İstanbul Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2025Periyodik potansiyelin fermiyonik sistemler üzerindeki etkileri, yoğun madde fiziğinin ana konularından birisidir. Periyodik potansiyel altındaki açık kuantum sistemlerinde, esnek olmayan çarpışmalar yüzünden, kayıplar meydana gelir. Bu kayıplar, hermitsel olmayan bir hamiltonyen ile modellenebilir ve artan kayıp oranı, süperakışkanlık üzerine monoton olmayan etkiler meydana getirebilir. Bu çalışmada, özellikle bu kayıpların, süperakışkan durum üzerine etkilerini incelemek istiyoruz. Bunun için bir boyutlu optik örgüde, iki parçacık problemini ve buna bağlı olan Cooper çifti problemini ele alıyoruz. Hesabı kolaylaştırmak için sadece ilk enerji bandını dikkate aldığımız "tek bant yaklaşımı" altında, sıkı bağ modelini kullanıyoruz. Parçacık kayıplarına sebep olan esnek olmayan çarpışmaları, kompleks etkileşim parametresi ile modelliyoruz. Nümerik çözümümüzde, hem konum hem de momentum bazında, hamiltoniyen matrisini oluşturup köşegenleştiriyoruz. Tek bant yaklaşımında; bağlı durum enerjilerini, kütle merkezi kuazimomentumu 'ya göre elde ediyoruz. Kompleks etkileşim olduğunda, belli enerji değerlerinde, bağlı durum eğrisinin sürekli bölge içinde oluştuğunu (BIC) ve kompleks etkileşim sabitinin artışının, bağlı durum eğrisinin 'ya göre varyasyonunu azaltarak eğriyi düz bir banda dönüştürdüğünü görüyoruz. Etkileşimin sanal kısmının; bağlanma enerjilerini azalttığını, sonlu ömürler oluşturduğunu ve yüksek sönüm oranlarında, bağlı durumların etkin kütlelerini arttırdığını gözlüyoruz. Belli bir limitte süperakışkan faz, Cooper çiftlerinin oluşturduğu, bir Bose Einstein yoğuşması (BEC) olarak düşünülebilir. Dolayısıyla bu çalışmada kayıp mekanizmasını, Bardeen-Cooper-Schrieffer süperakışkanlığın (BCS) temelini oluşturan, Cooper problemine taşıyoruz ve aynı hesapları orada, momentum uzayında tekrarlıyoruz. Sonuçlarımız, daha önce ortalama alan teorisiyle elde edilen, sanal kısma bağlı süperakışkan düzen parametresindeki monoton olmayan davranışın; iki parçacık fiziğinden kaynaklanabileceğini göstermektedir.Yüksek Lisan
Outpatient clinic layout design optimization using QAP-based generative modeling method
No full textPurpose This paper aims to present a generative design case study focused on optimizing outpatient clinic layouts. It addresses complex design challenges involving patient flow, spatial efficiency and operational performance in outpatient clinic facilities. The study aims to create adaptable, data-driven design frameworks that reduce walking distances, enhance patient experiences and improve overall operational efficiency in healthcare settings. Design/methodology/approach Using graph theory and shape grammar methods – including generative modeling and relational Quadratic Assignment Problem (QAP)-based evaluation – the study tackles a complex healthcare facility design problem with the requirements of local and international standards. These standards are interpreted through a space relationship matrix. The algorithmic framework was developed and implemented using visual programming tools. Design alternatives are generated and evaluated using the method to identify layouts that minimize operational costs. Findings The case study demonstrates a holistic approach that combines graph-based shape grammar representations, genetic algorithms for generative modeling and a stochastic selection process. The framework functions as an effective preliminary design support tool for architects and healthcare managers. The findings support the efficiency of the generative design model, as the QAP scores decrease with generation compared to precedent projects. Originality/value While existing literature often focuses solely on optimizing layout plans to improve patient flow and operational efficiency, this study simulates a generative design process. It incorporates precedent analysis, international standards, norms and design principles using a shape grammar rule set as a digital foundation. Each layout is assigned a unique score via the QAP, enabling objective comparison. As the score decreases, the level of optimization increases. This scoring system simplifies decision-making for selecting optimal outpatient clinic layouts during early design phases.https://doi.org/10.1108/sasbe-12-2024-054
Security Challenges in Cross-Chain DeFi Applications
No full texthttps://doi.org/10.1109/ubmk67458.2025.1120698
Quantitative Iron Measurements in the Basal Ganglia of NBIA Patients Using QSM : Insights From a Tertiary Center
No full textABSTRACT Objective Neurodegeneration with brain iron accumulation (NBIA) comprises rare genetic disorders characterized by predominantly extrapyramidal symptoms and iron deposition in the basal ganglia. Conventional magnetic resonance imaging (MRI) detects qualitative changes but cannot accurately quantify iron accumulation. Quantitative susceptibility mapping (QSM) allows precise in vivo quantification of iron, providing insight into the pathophysiology of the disease. Methods We studied 27 genetically confirmed NBIA patients and 11 age‐matched healthy controls using susceptibility‐weighted imaging (SWI) on a 3 Tesla MRI scanner. Basal ganglia regions of interest (ROIs) were manually delineated and QSM values were extracted. Results Sixteen NBIA patients and 11 controls were analyzed. QSM showed significantly higher iron in the globus pallidus (GP) ( p = 0.008), with PKAN patients showing a 2.5‐fold increase in GP iron ( p = 0.001). MPAN patients showed 2.5 times higher iron in both GP and substantia nigra (SN). A GP iron level > 0.1133 ppm increased the likelihood of PKAN 18‐fold. Atypical PKAN cases had 2.5 times higher SN iron levels compared to classic cases. Interpretation QSM is a sensitive and noninvasive tool for detecting and quantifying iron accumulation in NBIA. The GP consistently showed the highest susceptibility values across subtypes, emphasizing its significant role in disease pathology. Distinct patterns of iron deposition in different NBIA subtypes may reflect subtype‐specific mechanisms with diagnostic and therapeutic relevance. Age‐related susceptibility changes were found to be significant, reinforcing the need to account for age when interpreting QSM data. More importantly, QSM may serve as a candidate biomarker for longitudinal disease monitoring in future clinical trials targeting disease‐modifying therapies in NBIA.https://doi.org/10.1002/acn3.70161https://pubmed.ncbi.nlm.nih.gov/40817817/https://pmc.ncbi.nlm.nih.gov/articles/PMC12623849/https://hdl.handle.net/20.500.12831/2712