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Synthesis and electropolymerization of a selenophene based chemiluminescent monomer and its use in blood detection
No full textA new selenophene based trimeric chemiluminescent compound, namely 5,7-di(selenophen-2-yl)-2,3-dihydrothieno[3,4-d]pyridazine-1,4-dione (S2T-Lum), was synthesized in two steps via electron donor-acceptor-donor approach. Its chemiluminescent reaction with hydrogen peroxide was investigated in an alkaline solution in the presence of various catalysts such as different metal ions, hemin and blood samples and the results were compared with its thiophene analogue (T2T-Lum) and luminol. It was found that S2T-Lum was very sensitive to copper(II) and iron(III) ions, and blood samples. Also, it can be easily concluded that S2T-Lum as a new member of luminol type compounds is a potential candidate for the detection of blood findings in forensic science. Furthermore, S2T-Lum has an irreversible oxidation peak at 1.28 V vs Ag/AgCl, which is responsible from its electropolymerization. S2T-Lum was successfully polymerized electrochemically via potentiodynamic electrolysis without cleavage of its chemiluminescent active appendage. To the best of our knowledge, its corresponding polymer PS2T-Lum film is the first member of selenophene based luminol type electroactive polymers
Energy-constrained orienteering problem for green tourist trip design: Mathematical formulation and heuristic solution approaches
No full textPlanning a touristic itinerary is a challenging task that requires personalized tour generation for tourists interested in visiting available points of interest (POIs). The negative externalities of using vehicles (e.g., emissions) can be reduced by considering such aspects in itinerary planning. To address this need, we propose the Energy-Constrained Tourist Trip Design Problem to plan environmentally friendly touristic itineraries. We model this problem as an Energy-Constrained Orienteering Problem (ECOP), where we consider continuous vehicle speed, speed-dependent travel time, and fuel consumption −accordingly emissions− which have not been considered in the scope of the OP before. First, the ECOP is formulated as a mixed-integer second-order cone programming (MISOCP) model which is able to solve only small-size instances to optimality within a reasonable time. Second, for large-size instances, we develop two heuristic methods, namely Greedy Insertion (GI) and Iterated Local Search (ILS) algorithms. In the latter, several improvement heuristics are coupled with an SOCP-based speed optimization procedure. Based on our computational experiments, the GI heuristic is the fastest among the proposed methods, while generally yielding suboptimal solutions compared to the ILS algorithm, but for larger instances, these solutions are better than the ones obtained via the exact method. The ILS algorithm outperforms the exact method by reaching good-quality solutions in a relatively short computing time. The ECOP has prospective applications on selective routing problems involving other transportation modes (e.g., cruise, aerial) and has a significant potential on reducing transportation-related GHG emissions
Vakum lehimleme yöntemi ile birleştirilen Ti-6Al-4V alaşımı ve SiO2(f)/SiO2 kompozitlerin Ti-6Al-4V ve TiH2 tozları ile modifiye edilmiş lehim alaşımı ile arayüz mukavemetinin geliştirilmesi
No full textThis study aims to develop an appropriate brazing process for joining Ti6Al4V alloy and SiO2(f)/SiO2 composites, considering the components' characteristics and application requirements. Vacuum brazing was done using commercially available Incusil ABA and BAg-8 brazing filler alloys (in paste form) to maintain the process temperature below 900 ˚C. However, the wetting properties of these filler alloys on SiO2(f)/SiO2 composites are quite poor. Thus, to improve the joint strength these filler alloys were modified by adding different amounts of Ti6Al4V and TiH2 powders. To maintain the characteristics of the base material, the same heating and cooling profiles were used in all brazing experiments at temperatures between 750 and 850 ˚C with different holding times. Spreading areas of the filler alloys with varying powder concentrations were measured on the surfaces of the base materials. The hardness of the Ti6Al4V alloy was measured after brazing. Tensile tests on SiO2 fibers were conducted after heat treatments up to 800 °C, and compression test on SiO2(f)/SiO2 specimens were performed after each brazing processes. The strength of the joint was determined via the compressive shear tests. The maximum joint v strengths of about 16 MPa were obtained when 10 wt.% of the powder combination was added at a holding temperature of 800 ˚C and held for 15 and 30 minutes for Incusil ABA and BAg-8 filler alloys, respectively. The results of the mechanical tests were evaluated based on the microstructural examinations of the joint interfaces via SEM and EDS analysis.Bu çalışma, bileşen özelliklerini ve uygulama gereksinimlerini dikkate alarak Ti6Al4V alaşımı ve SiO2(f)/SiO2 kompozitlerini birleştirmek için uygun bir lehimleme yöntemi geliştirmeyi amaçlamaktadır. Vakum lehimleme, işlem sıcaklığını 900 ˚C'nin altında tutmak için ticari olarak temin edilebilen Incusil ABA ve BAg-8 dolgu alaşımlarının (macun formunda) kullanılmasıyla yapıldı. Ancak, bu dolgu alaşımlarının SiO2(f)/SiO2 kompoziti üzerindeki ıslatma özellikleri oldukça zayıftır. Bu nedenle, bağlantı kuvvetini artırmak için bu dolgu alaşımları, farklı miktarlarda Ti6Al4V ve TiH2 tozları eklenerek modifiye edildi. Ana malzemelerin özelliklerini korumak için, tüm lehimleme deneylerinde 750 ile 850 ˚C arasındaki sıcaklıklarda farklı bekletme süreleri ile aynı ısıtma ve soğutma profilleri kullanıldı. Farklı toz konsantrasyonlarına sahip dolgu alaşımlarının yayılma alanları, temel malzemelerin yüzeylerinde ölçüldü. Ti6Al4V alaşımının sertliği, lehimleme işleminden sonra ölçüldü. SiO2 elyafları üzerinde çekme testleri, 800 °C'ye kadar ısıl işlemlerden sonra gerçekleştirildi ve SiO2(f)/SiO2 örnekleri üzerinde basma testi, her lehimleme işleminden sonra yapıldı. Birleşme bölgesinin dayanımı, basma kesme vii testleri ile belirlendi. Maksimum birleşme dayanımları, 10 wt.% toz kombinasyonu 800 ˚C'de tutulduğunda, sırasıyla Incusil ABA ve BAg-8 dolgu alaşımları için 15 ve 30 dakika bekletildiğinde yaklaşık 16 MPa elde edilmiştir. Mekanik testlerin sonuçları, bağlantı arayüzlerinin mikro yapısal incelemeleri SEM ve EDS analizi aracılığıyla değerlendirildi.M.S. - Master of Scienc
Data-ing process with image-based data: variable identification and generation
Get PDFUsing photographs as data, which involves making observations from images and organizing them into variables to answer statistically investigative questions, is recommended for K-12 level statistics education. Research is needed to support pre-service mathematics teachers' experiences with exploring such image-based data. With this task-based interview study, the goal was to shed light on (1) the pre-service mathematics teachers' data-ing actions during identifying and generating variables in relation to data familiarization, question posing, and data organization components and (2) how pre-service mathematics teachers identified and generated variables in the process of data-ing. Data from video recordings, transcripts of the interview sessions for each pair, and their work with photos on the shared online document, that is, groupings and questions posed, were analyzed using a progressive focusing approach. The results showed that the data-ing actions during identifying and generating variables with data familiarization, question posing, and data organization included observing, interpreting, conjecturing, inferring, comparing, grouping, ordering, questioning/question posing, relating variables, categorizing variables, and measuring variables. The pairs used various combinations of multiple actions while data-ing. There were two types of variable identification: (1) observational variables based on visual judgment or metadata and (2) inferential variables based on personal interpretation. The latter type presented a tension between the variable defined and how to measure it objectively, as well as challenges in writing clearly defined variables when posing questions
Examining Non-Science Majors' Knowledge of Scientific Practices in Evaluating Scientific Media Claims
Get PDFThis study examines the knowledge of scientific practices that non-science undergraduate students need to critically evaluate scientific claims in the media. Employing a cross-sectional quantitative research design, the study gathered data through a self-report instrument involving 266 undergraduate students from non-science disciplines. A twelve-item, two-tier multiple-choice assessment was utilized, featuring questions from two research articles adapted from popular media. Findings reveal that non-science majors often struggle to understand the scientific practices necessary to evaluate scientific reports in mainstream media. Results also indicate that many participants fail to recognize the importance of controlled, randomized experimental designs in establishing cause-and-effect relationships. Additionally, findings suggest that students do not fully grasp that hypotheses are supported by evidence rather than proven and that scientific claims must be based on substantial proof. The study further shows that many participants underestimate the importance of peer review in validating scientific claims. Finally, the analysis revealed no significant gender differences in students' competencies related to critiquing these reports
Optimal liquidation with conditions on minimum price
No full textThe classical optimal trading problem is the closure of an initial position in a financial asset over a fixed time interval; the trader tries to maximize an expected utility under the constraint that the position is fully closed by terminal time. Given that the asset price is stochastic, the liquidation constraint may be too restrictive; the trader may want to relax the full liquidation constraint or slow down/stop trading depending on price behavior. We consider two additional parameters that serve these purposes within the Almgren-Chriss liquidation framework: a binary valued process I that prescribes when trading takes place and a measurable set S that prescribes when full liquidation is required. We give four examples for S and I which are all based on a lower bound specified for the price process. The terminal cost of the stochastic optimal control problem is ∞ over S; this represents the liquidation constraint. The permanent price impact defines the negative part of the terminal cost over the complement of S. The I parameter enters the stochastic optimal control problem as a multiplier of the running cost. Except for quadratic liquidation costs the problem turns out to be non-convex. A terminal cost that can take negative values implies 1) the backward stochastic differential equation (BSDE) associated with the value function of the control problem can explode to −∞ backward in time and 2) the existence results on minimal supersolutions of BSDE with singular terminal values and monotone drivers are not directly applicable. To tackle these we introduce an assumption that balances the market volume process and the permanent price impact in the model over the trading horizon. In the quadratic case, assuming only that the noise driving the asset price is a martingale, we show that the minimal supersolution of the BSDE gives both the value function and the optimal control of the stochastic optimal control problem. For the non-quadratic case, we assume a Brownian motion driven stochastic volatility model and focus on choices of I and S that are either Markovian or can be broken into Markovian pieces. These assumptions allow us to represent the value functions as solutions of PDE or PDE systems. The PDE arguments are based on the smoothness of the value functions and do not require convexity. We quantify the financial performance of the resulting liquidation algorithms by the percentage difference between the initial stock price and the average price at which the position is (partially) closed in the time interval [0, T]. We note that this difference can be divided into three pieces: one corresponding to permanent price impact (A1), one corresponding to random fluctuations in the price (A2) and one corresponding to transaction/bid-ask spread costs (A3). We provide a numerical study of the distribution of the closed portion under the assumption that the price process is Brownian for I = 1 and an S corresponding to a lower bound on terminal price
Effect of EDOT contribution on the electrochromic and capacitive properties of edot-carbazole based electrochromic polymer: Electrochromic and supercapacitor device applications
No full text3,4-ethylenedioxythiophene (EDOT) based donor-acceptor-donor (DAD) type conjugated polymers generally have extraordinary electrochromic properties due to the excellent nature of the EDOT unit. This work investigates the electrochromic properties of such a system; EDOT-Carbazole-EDOT (ECE) based DAD type of conjugated polymer. Electrochemically synthesized homopolymer film (PECE) showed multichromic behavior with excellent optical properties such as 34 % of optical contrast, subsecond switching response (0.96 s at 478 nm), high coloration efficiency (519 cm2/C at 478 nm) and remarkable specific capacitance (3.04 F/cm2). Inserting more EDOT units into the polymer matrix of PECE via electrochemical synthesis altered the spectral and capacitive behaviors of the resulting copolymers. 2:1 (ECE:EDOT) feeded copolymer exhibited better electrochromic performance than equal feeded copolymer. On the other hand, the capacitive range and capacitance stability were significantly enhanced as the EDOT unit increased in the copolymer matrix. PECE and its copolymers were used to construct dual-type electrochromic devices with poly(3, 4-ethylenedioxythiophene) (PEDOT). ECDs of PECE and copolymers exhibited superior stability upon many switchings, with subsecond switching responses. Furthermore, ECDs can be switched effectively even at the scan rate of 500 mV/s without any loss in charge/discharge amounts. Finally, electrochromic supercapacitor device applications were performed, and a 1.5 V-LED was lighted for up to 25 s with the copolymer supercapacitor device
Augmenting atmospheric turbulence effects on thermal-adapted deep object detection models
Get PDFAtmospheric turbulence poses a significant challenge to the performance of object detection models. Turbulence causes distortions, blurring, and noise in images by bending and scattering light rays due to variations in the refractive index of air. This results in non-rigid geometric distortions and temporal fluctuations in the electromagnetic radiation received by optical systems. This paper explores the effectiveness of turbulence image augmentation techniques in improving the accuracy and robustness of thermal-adapted and deep learning-based object detection models under atmospheric turbulence. Three distinct approximation-based turbulence simulators (geometric, Zernike-based, and P2S) are employed to generate turbulent training and test datasets. The performance of three state-of-the-art deep learning-based object detection models: RTMDet-x, DINO-4scale, and YOLOv8-x, is employed on these turbulent datasets with and without turbulence augmentation during training. The results demonstrate that utilizing turbulence-specific augmentations during model training can significantly improve detection accuracy and robustness against distorted turbulent images. Turbulence augmentation enhances performance even for a non-turbulent test set
Low-dose natural clay Kaolin promotes the growth of submerged macrophytes and alters the rhizosphere microorganism community: Implications for lake restoration
No full textSediment properties have a crucial effect on the growth and recovery of aquatic plants in lakes. Addition of various chemical substances has been proposed to reinforce the recovery of plants after a nutrient loading reduction. However, the effects of such sediment amendments on plant growth, especially those from rhizosphere microorganisms, is limited. We added Kaolin clay to sediments in different concentrations to explore its impact on the growth of Vallisneria natans and Ottelia acuminate and the concurrent shift in rhizosphere microorganisms using high-throughput sequencing technology. We found that the addition of low doses (10 % and 20 % in mass ratio) of Kaolin significantly modified sediment conditions (oxidation reduction potential and pH), with implications also for the composition, diversity, and stability of rhizosphere microorganisms. LEfSe analysis revealed that low-dose addition of Kaolin increased the abundances of functional microbial groups that benefit plant nutrient absorption and enhance plant stress resistance, such as Spirillaceae, Rhodocyclaceae, and Burkholderiales. Moreover, low doses of Kaolin significantly promoted the photosynthesis and nutrient absorption of submerged macrophytes, thereby facilitating plant growth. A structural equation model (SEM) indicated that the direct impact of Kaolin on the growth of submerged plants was relatively minor, while the indirect effect through modulation of rhizosphere microorganisms was important. Our study suggests that low doses of Kaolin may be used to promote the growth of submerged macrophytes when lakes with a high organic content in the sediment are recovering after nutrient loading reduction
Lider-takipçi görevinde motor kontrolde öngörünün kinematik ve kinetik metriklerle incelenmesi
No full textUnderstanding the processes of motor learning and skill acquisition is crucial in domains ranging from rehabilitation to performance training. This thesis investigates the role of anticipation mechanisms in a controlled leader-follower task, aiming to enhance motor adaptation through structured training protocols. Participants engaged in a virtual reality-based task using a gamepad to follow a dynamic leader, whose visibility was manipulated via deterministic and stochastic paradigms to elicit anticipatory behavior. Real-time feedback and data collection enabled analysis of motor learning trajectories. A comprehensive set of novel kinematic and kinetic metrics—adapted from robotics and time series analysis—was employed to assess movement synchrony, smoothness, and coordination. These metrics captured not only endpoint performance but also learning dynamics across phases. Significant improvements were observed in all groups from baseline to retention. However, group-level comparisons revealed no clear differences in final performance across protocols, including between stochastic and deterministic anticipation groups. Critically, slope-based analyses showed that anticipation-based training protocols were associated with faster learning rates in the full sample and among beginners. These effects were most pronounced in metrics such as score pause duration, temporal lag, and spatial error. The findings suggest that although final outcomes converge across groups, the rate and trajectory of motor learning are shaped by the training protocol. The developed platform enabled high-resolution behavioral analysis and showed potential as a tool for adaptive motor training and assessment. Future studies should examine individual differences in perception and adaptation and expand sample sizes to distinguish the impacts of different anticipation strategies.Motor öğrenme ve beceri kazanımı süreçlerini anlamak, rehabilitasyondan performans eğitimine kadar uzanan birçok alanda kritik öneme sahiptir. Bu tez, yapılandırılmış eğitim protokolleri yoluyla motor adaptasyonu geliştirmeyi amaçlayarak, kontrollü bir lider-takipçi görevinde öngörü mekanizmalarının rolünü araştırmaktadır. Katılımcılar, oyun kumandası kullanarak sanal gerçeklik tabanlı görevde dinamik bir lideri takip etmiş ve liderin görünürlüğü, öngörü davranışını tetiklemek amacıyla deterministik ve stokastik paradigmalar aracılığıyla manipüle edilmiştir. Gerçek zamanlı geri bildirim ve veri toplama, motor öğrenme süreçlerinin ayrıntılı analizini mümkün kılmıştır. Robotik ve zaman serisi analizlerinden uyarlanan kapsamlı bir yeni kinematik ve kinetik metrik seti, hareket eşzamanlılığı, akıcılığı ve koordinasyonunu değerlendirmek için kullanılmıştır. Bu metrikler, yalnızca nihai performansı değil, aynı zamanda eğitim aşamalarındaki öğrenme dinamiklerini de yakalamayı hedeflemiştir. Tüm gruplarda başlangıçtan kalıcılık aşamasına kadar anlamlı gelişmeler gözlemlenmiştir. Ancak grup düzeyinde yapılan karşılaştırmalar, özellikle deterministik ve stokastik öngörü grupları arasında olmak üzere, protokoller arasında nihai performans açısından belirgin farklar ortaya koymamıştır. Özellikle eğim temelli analizler, hem genel örneklemde hem de başlangıç düzeyindeki katılımcılar arasında, öngörüye dayalı eğitim protokollerinin daha hızlı öğrenme oranlarıyla ilişkili olduğunu göstermiştir. Bu etkiler, en belirgin şekilde skor duraklama süresi, zamansal gecikme ve konumsal hata gibi metriklerde ortaya çıkmıştır. Bulgular, nihai sonuçlar gruplar arasında yakınsamış olsa da, motor öğrenmenin hızı ve seyri üzerinde eğitim protokolünün yapısının etkili olduğunu göstermektedir. Geliştirilen platform, yüksek çözünürlüklü davranışsal analizleri başarıyla mümkün kılmış ve uyarlanabilir motor eğitimi ve değerlendirme aracı olarak potansiyelini ortaya koymuştur. Gelecek çalışmalarda, bireysel algı ve adaptasyon farklılıkları daha ayrıntılı olarak incelenmeli ve farklı öngörü stratejilerinin özgül etkilerini daha net belirleyebilmek adına örneklem büyüklüğü artırılmalıdır.M.S. - Master of Scienc