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Nanoarchitectonics of polyaniline derived carbon electrodes incorporating transition metal oxides for supercapacitor devices
No full textThis research explores the development and characterization of polyaniline (PANI)-derived carbon-based electrodes as electrode materials for supercapacitor applications. PANI is conducted through in situ copolymerization. Subsequent carbonization transforms the material, enhancing its inherent electrochemical properties. We further improve these materials by incorporating transition metal oxides, specifically manganese oxide (MnO2) and cobalt(II) nitride (Co(NO3)2), aiming to refine their electrochemical characteristics. Applying potassium hydroxide (KOH) as an activator expands the surface area and pore volume. Its surface area is among the highest carbon-based materials, with a value of 361.06 m2/g, as a PANI-derived activated carbon incorporating MnO2 (A.C-PANI:MnO2:KOH) with high micropores and mesopores. Electrochemical analyses show that MnO2 and Co3O4 incorporated reduced carbonized PANI's (C-PANI) specific capacitance, energy, and power density in symmetric designs while improving upon activation with KOH. Notably, the supercapacitor employing activated C-PANI:MnO2 as an electrode material displays exceptional performance, characterized by a specific capacitance reaching approximately 357 F/g. This underscores its potential as an outstanding candidate for high-efficiency supercapacitors. This study's promising synthetic method demonstrates the ability to produce nitrogen- and oxygen-containing carbon materials with a specific surface area for high-performance supercapacitors
Enhancing cognitive fit: exploring the potential of mixed reality for developing mental rotation skills
No full textMixed Reality is a promising venue for spatial ability training, allowing participants to engage in problem-solving through gesture-based interactions with holographic objects. 3-D measurement of learning in Mixed Reality environments may result in a better cognitive fit than 2-D. This mixed-method study measures and enhances mental rotation ability and investigates user experience in Mixed Reality. To assess mental rotation ability, we adapted the Purdue Spatial Visualization Test:Rotation for Microsoft HoloLens 2, creating a measurement tool for our Mixed Reality-based training program, Holomental. Comparing 2-D and 3-D tests, we explored how stimulus dimensionality influences accuracy and cognitive load. Our findings indicate that Holomental enhances mental rotation performance, both in 2-D and 3-D. Cognitive load in the 3-D test was lower than in the 2-D test. Semi-structured interviews revealed participants’ appreciation for the representational and interactional affordances of the training environment. This study provides valuable insights into the effectiveness of 3-D spatial training, with implications and suggestions for future design considerations
Bio-based polyethylene masterbatch preparation and investigation of the effect of process conditions on pigment dispersion
No full textAlthough the importance of bio-polyethylene is increasing, academic research on the subject is still limited. The dispersion level of pigments and functional additives plays a crucial role in achieving the desired effect from polymer composites. This study investigates the effects of additives and process conditions on pigment dispersion in bio-polyethylene masterbatches using four different factors and three different parameters by the Taguchi method. To achieve this, the relative colour strengths of extruder-produced masterbatches were measured using a spectrophotometer, blown film samples were visually observed and filter pressure values were examined in a filter tester. The results were subjected to Taguchi analysis to determine which factors and parameters are important to the process and which can be neglected. The study identified the physical properties of the wax, extruder screw speed, barrel temperature and mixer time as the most effective factors on pigment dispersion, respectively. Micronised wax was found to be the most critical parameter among wax types, while mixer mixing time was found to be the least important. It was observed in all the experiments that the colour strength obtained from a constant pigment content in the masterbatches was improved by increasing the dispersion and reducing the number of agglomerated particles
The role of the receptor activator of nuclear factor Kappa-B ligand/osteoprotegerin ratio in vascular diseases: a therapeutic approach
No full textCardiovascular and bone diseases contribute independently to mortality and global health. The exact mechanisms involved in the pathophysiology shared between bone and vascular diseases are not well defined. Endothelial cells and osteoblasts communicate during osteogenesis, thus establishing a connection between angiogenesis and osteogenesis. One shared mechanism may involve osteoprotegerin (OPG) and its ligand Receptor Activator of NF-κB Ligand (RANKL). The RANKL/OPG ratio is an important modulator for the skeletal, immunological, and vascular systems. OPG levels are elevated due to either osteogenic causes or inflammatory responses in the vasculature. The data obtained from clinical and in vitro studies support the role of the RANKL/OPG ratio as a potential marker for the progression of endothelial damage. Therefore, determining the therapeutic approaches for the targeting RANKL/OPG ratio and evaluating its usage as a biomarker in cardiovascular and bone pathophysiology are needed. By integrating the protective and disease-causing role of OPG with its ligand, this review outlines the role of the RANKL/OPG ratio at the molecular level. We also consider targeted therapeutic approaches
Electrochemical and defect characterization of APTES-functionalized Ti3C2Tx MXene for supercapacitor devices
No full textThis work comprehensively investigates the structural, surface, and electrochemical properties of MAX phase, MXene, and (3-aminopropyl)triethoxysilane-functionalized MXene (APTES-MXene) electrodes. The study developed a high-performance electrode design by APTES functionalization without incorporating conductive polymers, metal oxides, or carbon additions. The findings in the two-electrode system revealed that the APTES-MXene electrode exhibited a specific capacitance of 207.62 F g−1, an energy density of 28.83 Wh kg−1, and a capacity retention of 93.8%. The Dunn approach is utilized to determine the pseudo-capacitive contribution, demonstrating that the surface-controlled charge storage mechanism is dominant, with the capacitive contribution reaching 70.61%. The increase in charge transfer resistance following APTES modification in the EIS data signifies the creation of a more complicated ion transport structure due to the functional surface groups of the material and an extended interlayer distance. The increased capacity and cycle stability obtained can be attributed to the multifaceted influence of APTES on surface chemistry and ion accessibility. This study investigates the application of functionalized MXene in energy storage systems and highlights the significance of two-electrode measurements in assessing material performance under realistic operating conditions
Ready, Set, Remix: Layers Of Resistance In Turkey’s Digital Everyday Through Remix Videos
Full text linkThis thesis examines political remix videos and remix culture that have emergedwithin digital space, a virtual and stratified extension of everyday life, by focusingon the context of resistance in Turkey. It analyzes the transformation of the dissidentidentity and resistance narratives that surfaced during the 2025 Saraçhane protestswith the nostalgic affects tied to the 2013 Gezi Park protests and early Republicannarratives. By comparing remix videos from the 2010s to 2020s, it temporarilyand thematically traces the practice of remixing resistance as a new media formshaped by socio-political dynamics and technological environment. These emotionallyresonant audiovisual narratives, which have found a meaningful place on socialmedia platforms, are discussed as digital, everyday, and socially embedded tactics ofresistance against invisibility in traditional media and social forgetting. This analysisis based on de Certeau’s (1984) theory of strategies and tactics, emphasizingtheir mnemonic and communicative functions. It argues that media practices basedon user participation and multilayered reproduction in digital environments offer ameaningful contribution to, and reflection of, the formation of resistance identitiesand narratives in contemporary society
From Tension To Action: Understanding TheDynamics Of Anti-Refugee Mobilization
Full text linkCollective action literature has long focused on mobilization for the rights of disadvantagedgroups. However, with rising anti-minority sentiments, this focus hasbegun to shift toward mobilization against the disadvantaged. Refugees are one ofthese disadvantaged groups that advantaged members of host societies increasinglymobilize against. Given the growing number of refugees and the rising hostilitydirected at them, understanding the dynamics behind host society mobilization isnecessary for effective intervention. In the present work, I examine the psychologicalbackground of anti-refugee mobilization in Türkiye across two studies using amediation model. In Study 1 (N = 2209), I found that perceived threat and injusticepredicted collective action intentions against Syrian refugees, through fearand anger, respectively. However, while anger predicted both traditional and onlinecollective action intentions, for fear, this pattern was only significant for traditionalcollective action. In Study 2 (N = 335), I extended the model by adding dehumanizationand found that perceived threat and injustice again indirectly predictedstronger collective action intentions, through fear and anger, and then dehumanization.Overall, the findings support the established predictors of collective action andhighlight the additional role of dehumanization in anti-refugee mobilization. Furtherresearch is needed to establish causal pathways and explore the role of fear in moredetail
Juggling Regular And Irregular Verbs: b An Evaluation Of Rule- And Analogy-Based Models And The Role Of Executive Functions
Full text linkHumans are remarkably good at detecting and acquiring linguistic patterns. Oneunavoidable challenge is not making overregularization errors (*goed). ExecutiveFunctions (EFs) – inhibitory control (IC) and working memory (WM) – have beenproposed as potential mechanisms to overcome such errors, but evidence is inconsistent.This thesis evaluates a central assumption of the EF accounts: regulargrammatical rules are dominant over irregular inflections. The assumption alignswith rule-based explanations, which offer separate processing for regular and irregularverbs, but contradicts analogy-based explanations that assume a shared process.Study 1 extends the analyses of an existing dataset of Dutch-speaking adults byFerreira, Roelofs, and Piai (2020). Study 2 presents a new experiment with nativeTurkish-speaking adults, tested in their first (L1; Turkish) and second languages(L2; English). In Dutch and Turkish, participants were slower when switching tothe regular inflection after repeating irregular inflection (irregular-irregular-regular;IIR) than when alternating (regular-irregular-regular; RIR), supporting rule-basedexplanations. However, IC and WM measures did not predict the IIR-RIR difference,offering no support for EF accounts. The thesis also contrasts the processingof L1 and L2, extends the exploration to non-Indo-European languages, and comparestwo morphologically distinct languages, Dutch and Turkish, offering a morecomprehensive understanding of morphological inflection
A Dynamic Strategic Plan For The Transition To AClean Bus Fleet Using Multi-Stage Stochastic Programming
Full text linkIn recent years, the transition to clean bus fleets has accelerated. Although thistransition might bring environmental and economic benefits, it requires a long-termstrategic plan due to the large investment costs involved. This thesis proposesa multi-stage stochastic program to optimize strategic plans for the clean bus fleettransition that explicitly considers the uncertainty scenarios in the cost and efficiencyimprovements of clean buses.Our optimization model minimizes the total expected cost subject to emission targets,budget restrictions, and several other operational considerations. We proposea new forecasting approach that captures the correlation between technological improvementsto obtain realistic future pathways for Battery Electric Buses (BEBs)and Hydrogen Fuel Cell Buses (HFCBs), which are then given to the multi-stagestochastic program as scenarios. We also utilize a physics-based model for BEBs toaccurately capture their energy consumption and recharging needs.As a case study, we focus on the complex public bus network of Istanbul, whichaims to transition to a clean bus fleet by 2050. Utilizing real datasets, we solve afive-stage stochastic program spanning a 25-year planning horizon that involves 256scenarios to obtain dynamic strategic plans that can be used by policymakers.Our results suggest that BEBs are more advantageous than HFCBs, even in slow BEB but fast HFCB development scenarios. We also conduct several sensitivityanalyses to understand the effects of intermediate emission targets, budget limitations,and energy prices
A Wideband Single-Channel Receiver Front-End For C/X/KU/KA-BAND Satcom Systems
Full text linkThis thesis focuses on the design and implementation of a radio frequency (RF) integratedreceiver for satellite communication (SATCOM). Increasing the bandwidth isone of the key enablers to achieve higher data rates. In mm-wave, a larger bandwidthcan be allocated. Since Low-Earth orbit (LEO) SATCOM systems are promising forglobal connectivity and internet coverage, these SATCOM applications have gatheredattention recently. Currently licensed frequency bands for SATCOM receptionare C-, X-, Ku-, and Ka-bands. A wideband receiver RF module that covers theseSATCOM bands would be cost-efficient. On the other hand, due to orbiting aroundEarth at more than 200 km altitudes and utilizing mm-wave, the atmospheric pathloss is increased. To compensate for increased path loss, one can employ MIMOarrays.This thesis presents two separate single-channel receiver-ICs for SATCOM applications.The first receiver includes a low-noise amplifier (LNA) and a phase shifter.The designed receiver achieved a 6-bit phase resolution over a bandwidth of 5.7-25 GHz. The first receiver exhibits a peak output referred the third-order interceptpoint (OIP3) and input referred 1-dB compression point (IP1dB) of -22 dBmand -23.4 dBm, respectively, thanks to the post-distortion technique employed inthe LNA. The second receiver is based on sub-blocks: an LNA, a phase shifterattenuator,and a variable gain amplifier (VGA). The same post-distortion methodis applied in the LNA. A passive vector sum phase shifter topology is adopted toenhance linearity performance. The phase shifter architecture is based on a novelclose-loop voltage variable attenuator (VVA). The proposed VVA enables to achieve both phase and amplitude control functionality in a single block with low RMS phaseand amplitude error. Also, a quadrature hybrid coupler is utilized with a 1st-orderpolyphase filter (PPF) to obtain 6-bit phase resolution over a wide bandwidth. TheVGA is based on a distributed amplifier topology with an RC-feedback to obtainwideband low amplitude error. The second receiver achieves a gain of 25 dB, aminimum noise figure (NF) of 2.7 dB, and -23 dBm IP1dB over a wide frequencyrange of 7-26.4 GHz, which covers multiple licensed frequency bands for SATCOMreception. The second receiver provides 6-bit phase resolution with 5.6◦ RMS phaseerror and 36-dB attenuation range.To the best of the authors’ knowledge, this receiverachieved the highest attenuation range and highest linearity that supports themultiple licensed frequency bands for SATCOM reception thanks to passive vectorsum with the proposed VVA and the post-distortion method applied in the LNA