IYTE GCRIS Database (Izmir Institute of Technology)
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Effects of Edge Addition or Removal on the Nullity of a Graph
No full textLights Out is a game which can be played on any graph G. Initially we have a configuration which assigns one of the two states on or off to each vertex. The aim of the game is to turn all vertices to off state for an initial configuration by activating some vertices where each activation switches the state of the vertex and all of its neighbors. If the aim of the game can be accomplished for all initial configurations then G is called always solvable. We call the dimension of the kernel of the closed neighborhood matrix of the graph over the field Z2, nullity of G. It turns out that G is always solvable if and only if its nullity is zero. Moreover, the number of solutions of a given configuration is also determined by the nullity. We investigate the problem of how nullity changes when an edge is added to or removed from a graph. As a result we show that for every graph with positive nullity there exists an edge whose removal decreases the nullity. Conversely, we show that for every always solvable graph which is not an even graph with odd order, there exists an edge whose addition increases the nullity. We also show that if an always solvable graph is not even, then there is an edge whose removal increases the nullity. © 202
On-Site Measurements of Temperature and Humidity Conditions for the Comparison of Urban and Rural Sub-Spaces of Traditional Settlements: Historical City of Muğla, Turkey
No full textOne of the significant processes that ensures realistic determination of the energy needs of historical buildings is case-specific definition of their local microclimatic conditions. Accordingly, the aim of this study is to determine differences for the parameters of temperature and humidity in urban and rural sub-settlements of the historical city, Muğla/Turkey. Study method consists of on-site measurements of these variables in sub-settlements for comparisons. As a result, it was identified urban zone shows heat island characteristics with warmer, drier, and more stable conditions; while rural sub-settlement remains cooler, more humid, and more erratic. In parallel, calculated extents of these differences demonstrate the significance and necessity of on-site measurements and consequential microclimatic zoning of historical cities as conservation/planning tools for responding to the thermal needs of architectural heritage. A key application of these processes would be the establishment of local databases of case-specific weather data to be used in thermal simulation assessments. © 2023 Taylor ; Francis
Identifying Promoter and Enhancer Sequences by Graph Convolutional Networks
No full textIdentification of promoters, enhancers, and their interactions helps understand genetic regulation. This study proposes a graph-based semi-supervised learning model (GCN4EPI) for the enhancer-promoter classification problem. We adopt a graph convolutional network (GCN) architecture to integrate interaction information with sequence features. Nodes of the constructed graph hold word embeddings of DNA sequences while edges hold the Enhancer-Promoter Interaction (EPI) information. By means of semi-supervised learning, much less data (16%) and time are needed in model training. Comparisons on a benchmark dataset of six human cell lines show that the proposed approach outperforms the state-of-the-art methods by a large margin (10% higher F1 score) and has the fastest training time (up to 3 times). Moreover, GCN4EPI's performance on cross-cell line data is also better than the baselines (3% higher F1 score). Our qualitative analyses with graph explainability models prove that GCN4EPI learns from both text and graph structure. The results suggest that integrating interaction information with sequence features improves predictive performance and compensates for the number of training instances. © 202
Colloidal Quantum Dots as Solution-Based Nanomaterials for Infrared Technologies
No full textThis review focuses on recent progress of wet-chemistry-based synthesis methods for infrared (IR) colloidal quantum dots (CQD), semiconductor nanocrystals with a narrow energy bandgap that absorbs and/or emits IR photos covering from 0.7 to 25 micrometers. The sections of the review are colloidal synthesis, precursor reactivity, cation exchange, doping and de-doping, surface passivation and ligand exchange, intraband transitions, quenching and purification, and future directions. The colloidal synthesis section is organized based on precursors employed: toxic substances as mercury- and lead-based metals and non-toxic substances as indium- and silver-based metal precursors. CQDs are prepared by wet-chemical methods that offer advantages such as precise spectral tunability by adjusting particle size or particle composition, easy fabrication and integration of solution-based CQDs (as inks) with complementary metal-oxide-semiconductors, reduced cost of material manufacturing, and good performances of IR CQD-made optoelectronic devices for non-military applications. These advantages may allow facile and materials' cost-reduced device fabrications that make CQD based IR technologies accessible compared to optoelectronic devices utilizing epitaxially grown semiconductors. However, precursor libraries should be advanced to improve colloidal IR quantum dot synthesis, enabling CQD based IR technologies available to consumer electronics. As the attention of academia and industry to CQDs continue to proliferate, the progress of precursor chemistry for IR CQDs could be rapid. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved
Community Co-Creation Through Knowledge (co)production: the Engagement of Universities in Promoting Rural Revitalization in China
No full textThe global discourse on the role of universities in rural revitalization has gained significant attention. The proposition is to leverage university expertise and resources to support rural development, including knowledge (co)production, community co-creation, and volunteerism - a practice that essentially bridges local actors and their knowledge with external actors and their knowledge. As advocated by UN Habitat III, the collaboration between universities and rural communities is an initiative exemplified by China's "Jointly Create a Beautiful Environment and a Happy Life" to enhance the built environment. This study aims to comprehensively investigate the implementation and outcomes of the "Rural Four Small Gardens" projects, which serve as a vital community development initiative within the Hongtang Village in Fengqing County, Yunnan Province, China. The research discusses those processes, observing opportunities for knowledge (co)production across diverse stakeholders in line with neo-endogenous rural development thinking. By exploring the co-creation approach employed in these projects, we seek to unravel how academia and local communities collaborate to address multifaceted challenges in rural areas. We argue that: 1) The engagement of rural communities through collaborative planning workshops serves as the fundamental cornerstone for university paired-up assistance; 2) the co-creation model for improving rural settlement necessitates the collective efforts of multiple stakeholders; 3) university faculty and students play pivotal roles during the process of service learning, practice research, and knowledge (co)production with villagers; and 4) Knowledge (co)production entails a dynamic process of coconstruction, co-governance, and resource sharing, exemplified by co-creation initiatives of home development, farmyard enhancement, and infrastructure projects. The research offers insights for global universities seeking to engage in similar paired-up assistance initiatives, underscores the significance of co-creation in rural development, and enlightens planning education in practice and service
Radiative and Topological Properties of One-Dimensional Atomic Chains
No full textBu tezde, bir boyutlu, her birim hücresinde iki özdeş iki seviyeli atom bulunan bir diatomik zincirin topolojik ve vakum aracılı kolektif özellikleri incelenmiştir. Zincir üzerinde sabit sayıda uyarılmanın olduğu altuzayda, sistem, dissipatif etkileri dikkate alan non-Hermityen bir efektif Hamiltonyen ile tanımlanmaktadır. Zincirde tek bir uyarım varlığında, sonsuz bir zincir için kolektif radyatif davranış, öz durumları Bloch tipi durumlar olan etkin Hamiltoniyene karşılık gelen karmaşık enerji bantlarından ortaya çıkarılmıştır.Tek bir uyarıma sahip sonlu bir zincir için radyatif özellikler, sistemin etkin Hamiltonyeninin tam diyagonalizasyonuyla ortaya çıkarılmıştır. Altışınımlı durumların varlık koşulları belirlenmiştir. Ele alınan model, uzun menzilli etkileşimler ve dissipasyon nedeniyle genişletilmiş, non-Hermityen bir SSH modelidir. Bu sistem için topolojik özellikleri ortaya çıkarmak amacıyla kompleks Berry fazı hesaplanmış ve ardından topolojik olarak trivial olmayan durumlar için kenar durumları belirlenmiştir. Ayrıca, ışınımlı, altışınımlı ve topolojik kenar durumlarından gelen radyasyon desenleri, radyasyon bölgesindeki Poynting vektörünün hesaplanmasıyla gösterilmiştir.In this thesis, the topological and vacuum-mediated collective properties of a one dimensional diatomic chain consisting of two identical two-level atoms per unit cell are examined. In the subspace where there is a fixed number of excitations on the chain, the system is described by a non-Hermitian effective Hamiltonian which takes the dissipative effects into account. In the presence of a single excitation on the chain, collective radiative behavior for an infinite chain is revealed from the complex energy bands corresponding to the effective Hamiltonian whose eigenstates are Bloch type states. For a finite chain with a single excitation, the radiative properties are revealed by the exact diagonalization of the effective Hamiltonian of the system. We identify the conditions for the existence of subradiant states. The considered model is an extended, non Hermitian SSH model due to mediated long range interactions and dissipation. For this system, we calculate the complex Berry phase to reveal the topological properties, then we identify the edge states for the topologically non-trivial cases. Furthermore, radiation patterns from radiant, subradiant and topological edge states are shown by computing the Poynting vector in the radiation zone
Correlation of Low Field Nuclear Magnetic Resonance Relaxation With Composition and Glass Transition of Hard Candies
No full textHard candies produced from sucrose and doctoring agents such as glucose syrup (GS) and high fructose corn syrup (FS) have been investigated in terms of their final composition, glass transition temperature (Tg), degree of crystallinity, total soluble solids (TSS) content and water activity (aw). Time domain (TD) 1H NMR longitudinal relaxation time (T1) and second moment (M2) measurements have been used to understand the glassy state and crystallization characteristics for different hard candy formulations. The investigated candies include sucrose as the main sugar component. Different levels of doctoring agents have been mixed with sucrose to obtain products with different characteristics. It has been shown that addition of any doctoring agent to sucrose formulations decreases the Tg of the system significantly (p (Formula presented.) 0.05). Furthermore, GS or FS addition also induce significant changes in TSS and aw. T1 and M2 results are almost parallel to each other, both reaching the highest values for the highest sucrose concentration (p (Formula presented.) 0.05). The results demonstrate that the glass transition and crystallization characteristics of hard candy formulations can be monitored and analyzed by TD NMR relaxometry, alternative to other frequently used conventional methods including differential scanning calorimetry (DSC) and X-ray diffraction. Copyright © 2024 Ozel, Berk, Uguz, Grunin and Oztop
One-step hydrothermal synthesis of spinel manganese oxide ion-sieve from commercial Γ-Mno2 and its uptake performance for lithium
No full textThe selective extraction of lithium from aqueous systems necessitates efficient sorbent materials. Spinel-type lithium manganese oxide ion sieves (LMOs) have been bee recognized for their high performance in this application. However, the elevated market cost of the spinel form (λ-MnO2) raises economic concerns, posing challenges to the feasibility of the extraction process. In this study, the one-step hydrothermal synthesis of Li1.33Mn1.67O4 was carried out at 200 °C for 7 days using commercial γ-MnO2 powder and aqueous LiOH solution as reactants. The synthesized powder exhibited characteristic XRD reflections consistent with spinel Li1.33Mn1.67O4. Lithium ion-sieve (H1.33Mn1.67O4) was obtained by leaching the LMO product with dilute hydrochloric acid solution. The sorption capacity of γ-MnO2 is increased from 8.4 to 23.1 mg/g (C0=200 mg/L), this capacity is very close to the one of the commercial λ-MnO2. The synthesized spinel HMO sorbent achieved a maximum Langmuir adsorption capacity of 52.1 mg/g. The extraction efficiency reached 94% at the sorbent dose of 20 g/L. The distribution coefficients of metal ions were in the order Li+ > Ca2+ > K+ > Na+, emphasizing selective Li+ extraction from brines with high Na+ content. These findings highlight the successful development of a spinel-type lithium manganese oxide ion sieve from γ-MnO2 polymorph, which is nearly an order of magnitude cheaper than the selective λ-MnO2. The study addresses critical issue of economic feasibility in lithium extraction processes, providing a potential solution for the selective recovery of bulk lithium. © 2024 Elsevier Lt
Synthesis and Investigation of Quinone-Pyrrole Polymeric Materials for Zinc-Ion Batteries
No full textFosil yakıtların günümüzde yaygın kullanımı çevre üzerinde yıkıcı bir etkiye sahiptir. Bu durum, çevre dostu alternatif enerji kaynaklarının benimsenmesini zorunlu kılmıştır. Çinko-iyon piller, bu bağlamda önemli potansiyele sahip, gelişmekte olan yeni bir enerji depolama sistemi sınıfını temsil etmektedir. Bununla birlikte, bu teknolojiyi ilerletmekteki büyük zorluk, Zn2+ iyonlarını verimli ve geri dönüşümlü olarak barındırabilen katot malzemeleri geliştirmektir. Kinon bazlı konjuge polimerik malzemeler, redoks aktif yapıları, kolayca değiştirilebilen yapıları ve güçlü kimyasal ve termal kararlılıkları nedeniyle çinko-iyon pilleri için mükemmel katot seçenekleridir. Bu çalışmada, çinko-iyon pilleri (ÇİP'ler) için katot malzemeleri olarak kinon-pirol konjuge polimerik malzemeler (QRP'ler) sentezlendi. QRP'lerin içsel özellikleri, redoks merkezlerine etkili Zn2+ difüzyonunu kolaylaştırarak uzun vadeli döngü kararlılığını sağlar. QRP-1 ve QRP-2 sırasıyla 0.1 mA g-1 akım yoğunluğunda 180 mA h g-1 ve 134 mA h g-1 deşarj kapasitesi gösterdi. QRP'ler, 2.0 A g-1 akım yoğunluğunda 10000 döngü boyunca olağanüstü döngü kararlılığı göstererek, QRP-1 ve QRP-2 için sırasıyla 42 mA h g-1 ve 104 mA h g-1 olmak üzere oldukça yüksek final kapasiteleri elde edildi. Bu çalışmanın, kinon bazlı konjuge polimerik malzemelerin çinko-iyon piller için etkili katot malzemeleri olarak potansiyelini gösterdiğine ve enerji depolama alanında çalışan araştırmacılarının dikkatini çekeceğine inanıyoruz.The widespread use of fossil fuels today has a devastating effect on the environment. This situation necessitates the adoption of environmentally friendly alternative energy sources. Zinc-ion batteries represent a new, developing class of energy storage systems with significant potential in this regard. However, a major challenge in advancing this technology is developing efficient and reversible cathode materials that can accommodate Zn2+ ions. Quinone-based conjugated polymeric materials are excellent cathode choices for zinc-ion batteries due to their redox-active structures, easily modifiable structures, and strong chemical and thermal stability. This study synthesized two quinone-based redox-active polymers (QRPs) as cathode materials for zinc-ion batteries (ZIBs). The inherent properties of QRPs ensure effective Zn2+ diffusion into their redox centers, guaranteeing long-term cycling stability. QRP-1 and QRP-2 cathodes delivered discharge capacities of 180 mA h g-1 and 134 mA h g-1, respectively, at 0.1 mA g-1. Remarkably, QRPs maintained long-term cycling stability at 2.0 A g-1 over 10000 cycles, with final specific capacities of 42 mA h g-1 for QRP-1 and 104 mA h g-1 for QRP-2. We believe that this work demonstrates the potential of quinone-based conjugated polymeric materials as effective cathode materials for zinc-ion batteries and will attract the attention of energy storage researchers
Cinematographic Expressions of Diasporic Experience: Decades of Turkish-German Cinema
No full textThis chapter presents an analytical account of Turkish diasporic cinema, particularly in Germany for Turkish-German diasporic cinema constitutes one of the most prominent examples. Foregrounding ethnic constituency, the analysis traces how differing perceptions and recollections of dislocation, migration, and the overall diasporic experience have shaped the films of different generations. At the heart of the discussion are questions such as the following: What are the ways the films intersect, shape, contradict, and/or enhance received ideas about migration, diasporic experience, and Turkish/German as well as multiplied ethnic and cultural identities (Kurdish-German, Kurdish-Turkish, Muslim German, Shiite Kurdish, and so on)?; How are contested issues such as gender, sexuality, queer positionalities, diasporic subjectivity, collective memory, and integration addressed in the films?; What does the range of filmmaking styles and modes, genres, formalistic structures, cinematic narratives, and aesthetics tell us about this particular cinema?. © 2024 Taylor ; Francis