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Nauplius Swimming Robot
No full textBarnacle nauplii swim in conditions described by a low Reynolds number of around 2 as a result of their small size. It is not fully understood how their method of swimming allows them to move around in an environment with such a low Reynolds number. Additionally, it is unknown to what degree their horns, tail, and the hair-like bristles on their appendages contribute to their motion and their survival. The robot prototype created for this project mimics the features and swimming method of nauplii in order to help study nauplius locomotion and the functions of their unique morphology. Additionally, this robot was created with the goal of helping to determine how well-suited a robot that mimics a nauplius is for navigating highly viscous environments, such as the oceans of Europa. A robot prototype was created that utilizes a motor and series of gears and sliders to move legs back and forth. The angles of legs of the robot were matched to the angles of those of an actual nauplius with reasonable accuracy. Viscosity tests were performed and showed that viscosity could be controlled to match the Reynolds number of the robot to that of a nauplius. Future work will need to be done to waterproof the system and test it in a viscous fluid
SilentTalk Final Report
No full textSilentTalk is a noninvasive communication system that uses ultrasound technology to detect and interpret silent speech by analyzing lip and facial movements. This E90 project presents the design, construction, and experimental evaluation of a speaker–microphone device capable of emitting and capturing ultrasonic waves in the 20–55 kHz range. Data wereadS collected under five distinct conditions, including various static mouth gestures, and analyzed using Root Mean Square (RMS) smoothing and Fast Fourier Transform (FFT) techniques. The results show that the distinct features in the time and frequency domains correspond to different mouth shapes, supporting the feasibility of silent gesture classification. A method based on the standard deviation of the RMS voltage was proposed to detect the presence of a human face. The findings highlight the importance of consistent ultrasonic output and gesture variability in real-world applications. Future directions include improving hardware portability, improving signal stability, and integrating phonetic modeling and machine learning to enable silent real-time communication across languages
Progress toward the synthesis of pyridine-containing macrocycles using dynamic alkyne and olefin metathesis
No full textTubular structures are ubiquitous in nature and possess functions ranging from the structural ones played by microtubules to transporting necessary ions across cell membranes by membrane proteins. In addition, the excellent electronic and structural properties of carbon nanotubes have made them of great interest to chemists. Yet, the functionalization of these nanotubes is hindered by unselective post-modification, often requiring harsh reaction conditions. As such, the assembly of macrocycles into nanotubular structures has been widely studied by chemists. One such way to make these materials is by using dynamic, reversible reactions to synthesize pyridine-containing macrocycles in high yields. Due to inherent strength of carbon-carbon bonds, the Yang Group is interested in synthesizing pyridine-containing macrocycles using dynamic alkyne and dynamic olefin metathesis. Despite the advantages offered by both of these reactions, they are ultimately limited by their poor tolerance of Lewis basic groups like pyridine.
This thesis explores the synthesis of these macrocycles from two different approaches. First, I investigate the origins of a catalyst deactivation by pyridinyl substrates during alkyne metathesis using small molecule test substrates. I suggest that the product of alkyne metathesis on pyridinyl substrates plays a critical role in deactivating the catalyst. I then continue to use these small molecule test substrates to test various ways to overcome this low reactivity. Second, I apply the findings from my small molecule test reactions to synthesize pyridine-containing monomers for alkyne or olefin metathesis. The results from this thesis provide a guide for the synthesis of metathesis-compatible monomers, which will be explored further by the Yang Group
Discovery and Synthesis of Novel, Porous Organic Cages via Dynamic Imine Chemistry in Continuous Flow
No full textIn recent years, Porous Organic Cages (POCs) have gained widespread research interest owing to the well-defined porosity and solution dispersity, which have given rise to various applications, such as molecular encapsulation and catalysis. A common synthetic strategy for POCs, Dynamic Covalent Chemistry (DCvC) exploits the reversibility of certain covalent reactions and allows for facile discovery and synthesis of well-defined macromolecules through error-correction mechanisms. Thermodynamic effects of DCvC systems have been widely studied via structure-focused strategies along with empirical methods. More recently, researchers have begun to incorporate kinetic factors in DCvC systems to discover and synthesise new macromolecular structures. However, thermodynamic and kinetic effects are often studied in isolated contexts. The combination of both thermodynamic and kinetic effects, which define energy landscapes of DCvC systems, has been scarcely investigated. As a result, there is a lack of sustainable methods to navigate the energy landscapes of DCvC reactions in general. Addressing the issue will allow for fine tuning of product distribution in a DCvC system, which will in turn promote our understanding of the corresponding DCvC system through exploring new reaction pathways.
This thesis demonstrates the possibility of using continuous flow chemistry as a sustainable method to navigate energy landscapes of DCvC reactions. A trialdehyde building block with alternating “up-down” substitution pattern was designed to guide the dynamic assembly pathways to potentially form [2+3] and [4+6] imine cages with commercially available diamine building blocks. Structures of all monomers and their corresponding molecular cages were modelled and optimised at their local minima with ab initio methods. Then, syntheses in both batch and continuous flow conditions were carried out. The product distributions were characterised by Gel Permeation Chromatography (GPC) and 1H Nuclear Magnetic Resonance (1H NMR). The results revealed that in continuous flow, the imine condensation reaction quickly reaches equilibrium, but imine exchange keeps taking place rapidly. Both retention time and temperature can systematically affect product distribution
Misinformation, Disinformation, And Propaganda In Greek Historiography
No full textMindful of the present state of discourse on ancient Greek historiography, this edited volume explores the major themes of pursuing factuality, managing witness/source bias, falling into historical error and creating or confronting propaganda.Even the greatest ancient historians, striving for factuality and truthfulness, must commence from subjectivity. Their works, when studied closely, reveal biases and conceptual or ideological distortions – their own and others’. For this reason, Misinformation, Disinformation and Propaganda in Greek Historiography strives to evaluate the issues which stand in the way of factuality in historical texts and records. The contributors, all experts in the field, explore and question the accuracy of the historiography in question; the ancient author’s fidelity to their sources; and the evidence presented in relation to inherited oral traditions. In this way, an ancient author’s methodology is evaluated in terms of its probability, the awareness of its cultural variation and the influences which we can deduce within the texts. This volume presents an important contribution to the study of what constitutes fact and fiction within ancient Greek historiography
Conversations And Deliberations: Non-Standard Cosmological Epochs And Expansion Histories
No full textThis paper summarizes the discussions which took place during the PITT-PACC Workshop entitled “Non-Standard Cosmological Epochs and Expansion Histories,” held in Pittsburgh, Pennsylvania, Sept. 5–7, 2024. Much like the non-standard cosmological epochs that were the subject of these discussions, the format of this workshop was also non-standard. Rather than consisting of a series of talks from participants, with each person presenting their own work, this workshop was instead organized around free-form discussion blocks, with each centered on a different overall theme and guided by a different set of Discussion Leaders. This document is not intended to serve as a comprehensive review of these topics, but rather as an informal record of the discussions that took place during the workshop, in the hope that the content and free-flowing spirit of these discussions may inspire new ideas and research directions
Local Power Play: The Post-Election Repression And Local Governance
No full textWe explore the aftermath of electoral defeats for incumbents in competitive authoritarian regimes, positing that they escalate repression in response. While prevailing research on competitive authoritarian regimes typically analyses incumbent repression at the national level, we focus on its effects on local political actors. Our argument centres on subnational variation in repression, influenced by the incumbent’s strength within the local city council. Specifically, incumbents tend to employ legislative blockage to hinder opposition mayors from efficiently delivering public goods when their party holds a majority of seats in the city council. We present original data on legislative proposals in city councils and employ a mixed-method approach to investigate this phenomenon. The 2019 local elections in İstanbul offer a unique opportunity to probe the dynamics of repression against the opposition at the local level. Our findings underscore that repression neutralizes emerging political leaders, thereby undermining municipal administration in the process
Life Among The Sand Grains
No full textHave you ever played with sand at the beach? Did you know you were also playing with thousands of tiny animals? The sand in the ocean is home to many small creatures called meiofauna, but you can only see them under a magnifying glass or microscope. Meiofauna are so tiny that sand grains seem like boulders to them. Meiofauna are too small to move these boulders, so they wriggle through spaces between them. Living in such tight spaces has led them to evolve long, skinny body shapes like worms. They also have special body parts to grip sand grains and avoid being washed away. Meiofauna are small, but they still play a big role in the ocean, feeding larger animals and recycling waste on the ocean floor. There are tens of thousands of species of meiofauna worldwide, and many more are waiting to be discovered