ADDITIVE MANUFACTURING AND CHARACTERIZATION OF CONDUCTIVE NANOMATERIALS AS ELECTROCHEMICAL ACTUATORS

Actuators are widely used in many medical devices for a variety of surgical purposes. These actuators are also applicable in many prosthetic devices, and they are fabricated in a range of sizes depending on their usage. Also, they have different types of actuating mechanisms. Here, we investigate an electrochemical mechanism for an actuator for potential use in medical devices, and this mechanism is achieved using a nanocomposite. Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is used as the polymer matrix with carbon nanotubes (CNTs) as a nanomaterial additive. This PEDOT:PSS and CNTs nanocomposite is used to 3D print filaments, which are then characterized for electrochemical and mechanical properties. The ink was prepared by mixing aqueous PEDOT:PSS solution with CNTs. CNTs were first mixed with a surfactant - Triton X-100 - for dispersion by ultrasonication with a probe-sonicator. Also, dimethyl sulfoxide was added to PEDOT:PSS to give the solution a gel-like texture. The ink was loaded in a syringe, attached to the 3D printer, and filaments were printed at different pressures and speeds. To evaluate the electrical and structural properties, characterization tests were performed. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed to obtain capacitance and resistance of the printed filaments. Furthermore, linear actuation tests were performed to determine the strain developed in the printed filaments. Voltage ranging from -1.2V to 1.2V was passed through the filaments immersed in an electrolytic solution for all the tests. A 0.5 mN of force was applied for the linear actuation tests in the filament. The study showed the significance of printing conditions, especially printing speed, in the specific capacitance of the printed filaments, likely due to the alignment of CNTs in the printing direction. Another influential factor was the width of the printed filaments. Thinner filaments appeared to have higher specific capacitance and lower values of impedance multiplied by surface area/mass. A larger portion of CNTs in thinner filaments is influenced by the shear forces applied by the nozzle, which is likely the reason for the effect of filament width. This work could serve as a guideline for fabricating capacitors and actuators with better performance for a wide range of applications

Studies on Biologically Active Synthetic Compounds

Not availabl

Rumination and Positive Autobiographical Memories in Depression: An Examination of the Undermining Effect of Maladaptive Emotion Regulation on Adaptive Emotion Regulation

Major Depressive Disorder (MDD) is a highly prevalent disorder of a recurrent nature that enacts a high burden across many domains. MDD has been conceptualized as a disorder of emotion regulation deficits in the frequent use of maladaptive ER responses as opposed to adaptive ER responses. While adaptive ER responses have been generally found to be efficacious in reducing distress within laboratory settings, they often fail to predict depression symptoms, do not differentiate those at high- from low-risk for MDD, and do not prognosticate risk for new MDD episodes. Given the preponderance of evidence suggesting a reliance on maladaptive ER among depressed persons and those at risk for the disorder, it is feasible maladaptive response deployment precedes and undermines the effectiveness of adaptive ER responses. The present study sought to test this possibility in a sample of 59 adults who following a negative mood induction either deployed an adaptive ER response (recalling a Positive Autobiographical Memory, PAM) or maladaptive ER (engaging in rumination) that preceded PAM. Contrary to expectation, neither rumination, participants’ depression levels, nor their interaction undermines PAM’s mood repair effects. An interaction between ER response sequence and depression levels was observed regarding the negative affect endorsed post-PAM. Moderation analysis revealed that those who immediately recalled PAM following mood induction endorsed higher negative affect compared to those who ruminated prior to PAM

Coreset Clustering on Small Quantum Computers

Many quantum algorithms for machine learning require access to classical data in superposition. However, for many natural data sets and algorithms, the overhead required to load the data set in superposition can erase any potential quantum speedup over classical algorithms. Recent work by Harrow introduces a new paradigm in hybrid quantum-classical computing to address this issue, relying on coresets to minimize the data loading overhead of quantum algorithms. We investigate using this paradigm to perform $k$-means clustering on near-term quantum computers, by casting it as a QAOA optimization instance over a small coreset. We compare the performance of this approach to classical $k$-means clustering both numerically and experimentally on IBM Q hardware. We are able to find data sets where coresets work well relative to random sampling and where QAOA could potentially outperform standard $k$-means on a coreset. However, finding data sets where both coresets and QAOA work well--which is necessary for a quantum advantage over $k$-means on the entire data set--appears to be challenging

Direct Digital Synthesis: A Flexible Architecture for Advanced Signals Research for Future Satellite Navigation Payloads

In legacy Global Positioning System (GPS) Satellite Navigation (SatNav) payloads, the architecture does not provide the flexibility to adapt to changing circumstances and environments. GPS SatNav payloads have largely remained unchanged since the system became fully operational in April 1995. Since then, the use of GPS has become ubiquitous in our day-to-day lives. GPS availability is now a basic assumption for distributed infrastructure; it has become inextricably tied to our national power grids, cellular networks, and global financial systems. Emerging advancements of easy to use radio technologies, such as software-defined radios (SDRs), have greatly lowered the difficulty of discovery and exploitation of vulnerabilities to these systems. The promise of a Direct Digital Synthesis (DDS) architecture provides the flexibility of incorporating countermeasures to emerging threats while maintaining backward capability with existing GPS signals. The objective of the proposed research is to determine if DDS architecture is a viable replacement for legacy GPS SatNav payloads. The overall performance of several architectures is analyzed and evaluated. The architecture with the best performance is chosen and implemented onto a programmable logic device, and GPS signals are generated. The advantages and disadvantages of using the DDS model are discussed and an end-to-end numerical and mathematical models are developed. The end-to-end mathematical model analyzes the quantization effects of the DDS architecture, and it predicts the location and power levels of the desired signal and spurious content present in the spectrum. The spurious content may potentially cause intermodulation distortion to the desired signal. The appropriate DDS architecture and resources are selected by the information gained from the mathematical model

Contrast inversion in neutral atom microscopy using atomic cluster beams

This work explores the possibility of atomic cluster beams as a probe for neutral atom microscopy (NAM) measurements. Using a beam of Kr clusters with mean size $\sim$ 10$^4$ atoms/cluster we demonstrate that topographical contrast can be obtained, similar to that in the case of monoatomic beams. Further, using atomically thin films of MoS$_2$ grown on SiO$_2$/Si substrate we show that NAM imaging using Kr clusters is also possible in domains where topographical contrast is not expected. Surprisingly, these images show an inverted contrast pattern when compared to the case of monoatomic beams. We attempt to understand these observations on the basis of angular distributions resulting from cluster-surface scattering. Finally, we discuss the implications of these results towards achieving a high lateral resolution neutral atom microscope using atomic cluster beams.Comment: Main manuscript: 10 pages, 6 figures and Supplementary information: 5 pages, 5 figure

The curious case of CO2_2 dissociation on Cu(110)

Dissociation of CO$_2$ on copper surfaces, a model system for understanding the elementary steps in catalytic conversion of CO$_2$ to methanol has been extensively studied in the past. It is thought to be reasonably well-understood from both experiments and theory. In contrast, our findings reported here suggest a different picture. Using molecular beam surface scattering methods, we measure the initial dissociation probabilities ($S_{\rm 0}$) of CO$_2$ on a flat, clean Cu(110) surface under ultra-high vacuum conditions. The observed $S_{\rm 0}$ ranges from $3.9\times10^{-4}$ to $1.8\times10^{-2}$ at incidence energies of 0.64 eV to 1.59 eV with a lower limit to dissociation barrier estimated to be around 2.0 eV, much larger than that understood previously. We discuss the possible reasons behind such large differences in our results and previous work. These findings are anticipated to be extremely important for obtaining a correct understanding of elementary steps in CO$_2$ dissociation on Cu surfaces.Comment: Main manuscript: 15 pages, 5 figures, Supplementary Information: 11 pages, 6 figure

Enhancing Room Security and Automating Class Attendance Using ID Cards

With the rapid advancements in technology, automation has emerged as the future of human endeavors. From simple tasks like attendance management to complex security systems, automation has the potential to revolutionize various aspects of our lives. This research paper explores the implementation of a method aimed at enhancing room security in hostels and automating class attendance using ID cards. In this study, we propose a system that utilizes the unique identity information stored in ID cards for various security and check-in tasks. By integrating RFID (Radio-Frequency Identification) reader technology, GSM modules, Node MCU, and Arduino, we create a comprehensive solution. The RFID reader scans the ID card, extracting the relevant information and verifying the user's identity. The data is then transmitted via the GSM module to a central database, ensuring real-time monitoring and security measures. Moreover, the system also enables the automation of class attendance. By utilizing the same ID cards, students can simply tap their cards on a reader placed in the classroom. This information is recorded automatically, eliminating the need for manual attendance taking and reducing errors and time consumption. This research project highlights the practical implementation of ID card technology to enhance room security in hostels and automate class attendance processes. By leveraging the power of automation, we aim to streamline administrative tasks, improve security measures, and optimize efficiency in educational institutions and other relevant settings.Comment: 7 pages, 5 figure

Identification and Partial Characterization of an L-Tyrosine Aminotransferase (TAT) from Arabidopsis thaliana

The aminotransferase gene family in the model plant Arabidopsis thaliana consists of 44 genes. Twenty six of these enzymes are classified as characterized meaning that the reaction(s) that the enzyme catalyzes are documented using experimental means. The remaining 18 enzymes are uncharacterized and are therefore deemed putative. Our laboratory is interested in elucidating the function(s) of the remaining putative aminotransferase enzymes. To this end, we have identified and partially characterized an aminotransferase (TAT) enzyme from Arabidopsis annotated by the locus tag At5g36160. The full-length cDNA was cloned and the purified recombinant enzyme was characterized using in vitro and in vivo experiments. In vitro analysis showed that the enzyme is capable of interconverting L-Tyrosine and 4-hydroxyphenylpyruvate, and L-Phenylalanine and phenylpyruvate. In vivo analysis by functional complementation showed that the gene was able to complement an E. coli with a background of aminotransferase mutations that confers auxotrophy for L-Tyrosine and L-Phenylalanine