Electrodeposition of Pure and Doped ZnO

A study of the electrodeposition of pure and doped zinc oxide from a basic solution was completed using SEM, EDS, UV-Vis, and XRD analysis. The presence of a highly ordered zinc oxide film was confirmed. The doping of zinc oxide films with 3, 5, and 10 at wt% chromium was documented. Tests were run to ensure the incorporation of chromium from solution and not the substrate which also contained chromium. Aluminum was doped into zinc oxide films at 3, 5, 10 and 20 at wt% but its presence could not be determined using these characterization techniques

The Effects of a High Fat Meal on Blood Flow Regulation during Arm Exercise

A diet high in saturated fats results in endothelial dysfunction and can lead to atherosclerosis, a precursor to cardiovascular disease. Exercise training is a potent stimulus though to mitigate the negative effects of a high saturated fat diet; however, it is unclear how high-saturated fat meal (HSFM) consumption impacts blood flow regulation during a single exercise session. PURPOSE: This study sought to examine the impact of a single HSFM on peripheral vascular function during an acute upper limb exercise bout. METHODS: Ten young healthy individuals completed two sessions of progressive handgrip exercise. Subjects either consumed a HSFM (0.84 g of fat/kg of body weight) 4 hours prior or remained fasted before the exercise bout. Progressive rhythmic handgrip exercise (6kg, 12kg, 18kg) was performed for 3 minutes per stage at rate of 1 Hz. The brachial artery (BA) diameter and blood velocity was obtained using Doppler Ultrasound (GE Logiq e) and BA blood flow was calculated with these values. RESULTS: BA blood flow and flow mediated dilation (normalized for shear rate) during the handgrip exercise significant increased from baseline in all workloads, but no differences were revealed in response to the HSFM consumption. CONCLUSION: Progressive handgrip exercise augmented BA blood flow and flow mediated dilation in both testing days; however, there was no significant differences following the HSFM consumption. This suggests that upper limb blood flow regulation during exercise is unaltered by a high fat meal in young healthy individuals.https://scholarscompass.vcu.edu/gradposters/1060/thumbnail.jp

Developing new functional TCs

Transparent Conductors (TCs) are increasingly critical to the performance and reliability of a number of technologies. Traditionally based primarily on oxides of Ga, In, Zn and Sn the class is rapidly expanding into new materials including both other oxides and more recently composites of metallic or carbon nanowires. Many of these materials offer unique functionality as well as processing and reliability advantages over some of the historic materials. These compounds are all classically non-stoiciometric and often metastable consisting of oxide, non-oxide and composite materials which are being collectively looked at for an increasingly broad set of applications including photovoltaics, solid state lighting, power electronics and a broad class of flexible and wearable electronics. In this talk, we will focus on two main areas; the development of predictive models to be able to identify dopants and the processing regimes where they can be activated as well as the use of nanowire oxide composites to develop a new generation of tunable high performance TC. The complex set of demands for a desired TC include not only classical performance, but also processibility, cost and reliability necessitating a search for new materials. The ability to use materials genomics to identify new dopable TC materials that are experimentally realizable is rapidly increasing. We will discuss recent work on predicting the dopability of Ga2O3 films, which potentially have broad applicability as buffer layers, TCOs, and in power electronics if the doping level can be well controlled. We will discuss the theoretical predictions for the process windows to activate both Sn and Si as dopants and compare this to experimental results and the literature. We will also present resent results on the theoretical prediction and realization of a new p-type TC based on CuZnS, which has demonstrated conductivities of up to 100 S/cm. The latter while not classically an oxide is certainly non-stoichiometric and properties are enhanced in many cases by the use of complex oxide, sulfide and selenide materials. Together these will illustrate the evolving tools both theory and experiment to develop and realize dopants in wide band gap materials. In cases where single materials may not be sufficient, nanowire (metal or carbon based) composites with oxides is increasingly attractive. For example, Ag, and potentially Cu, nanowires embedded in a metal oxide matrix can potentially produce TCs that can be processed at low temperature, have conductivity and transparency comparable to the best TCOs, control interface stability and electronic properties and are suitable to flexible electronics. We will present work on ZnO, InZnO and ZnSnO composites with Ag nanowires where the performance can be as good as high quality InSnO with films Rs\u3c 10 Ohms/sq. We will discuss the dependence on the interrelationship between the nanowire properties and the oxide properties. We will also discus the concept of employing sandwich oxides to separately optimize the top and bottom interfacial properties. This work was supported, in part, by the Center for the Next Generation of Materials by Design, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. This research also supported in part by the Solar Energy Research Institute for India and the U.S. (SERIIUS) funded jointly by the U.S. Department of Energy subcontract DE AC36-08G028308 (Office of Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy, Solar Energy Technology Program, with support from the Office of International Affairs) and the Government of India subcontract IUSSTF/JCERDC-SERIIUS/2012 dated 22nd Nov. 2012

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Determining the Impact of Strain on Magnetoelectric Coupling in Artificial Multiferroic Heterostructures

Presented on February 22, 2022 from 12:00 p.m.-1:00 p.m. in the Marcus Nanotechnology Building, Rooms 1116-1118, Georgia Tech, Atlanta, GA.Lauren Garten started as an assistant professor in Materials Science and Engineering at Georgia Tech in 2021. Prior to that she was a staff scientist at the U.S. Naval Research Lab (NRL) working on the growth and characterization of novel piezoelectric and artificial multiferroic heterostructures for sensors and electronics. Her work at NRL was supported by the Jerome and Isabella Karle Distinguished Fellowship and a National Research Council Associateship. Prior to this, she was a staff scientist in ferroelectric metrology development at Sandia National Laboratory and a post-doc at the National Renewable Energy Laboratory (NREL) where she worked on the processing and characterization of metastable photovoltaic materials. She received her Ph.D. in material science from the Pennsylvania State University on the development of piezoelectric and ferroelectric materials for tunable dielectrics, and her bachelor’s degree is in ceramic engineering from the Missouri University of Science and Technology. She has won the AFOSR Young Investigator Award, the DOE-BES Postdoctoral Research Award, the Outstanding Mentor Award from NREL, and the CalTech Young Investigator Lectureship. Her work focuses on the development of multifunctional multiferroics for energy and electronic applications, particularly at the nexus between ferroelectricity, magnetism, and photovoltaics.Runtime: 48:39 minutesMagnetoelectricity presents a unique opportunity to control the magnetic response of a material with an applied electric field or vice versa. Unfortunately only a few materials exhibit controllable magnetoelectric coupling (ME) within a single phase, and even then, the response is typically small and below room temperature. One route to enhance ME coupling is to create a composite between a ferroelectric and ferromagnetic material. This type of ME coupling can be mediated in multiple ways, but the current most successful method is through strain transfer across an interface. These artificial multiferroic heterostructures can exhibit ME coupling up to six orders of magnitude larger than within a single material. Still further improvement must be made before ultra-low power memory, logic, magnetic sensors, and wide spectrum antennas can be realized. In this talk I will describe how ME coupling can be enhanced by simultaneously exploiting multiple strain engineering approaches. This work is conducted on heterostructures composed of Fe0.5Co0.5/Ag multilayers on (011) Pb(In1/2N1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 piezoelectric crystal substrates. When grown and measured under strain these heterostructures exhibit an effective converse magnetoelectric coefficient on order of 10-5 s/m: the highest directly measured, non-resonant value to-date. Additionally, this response occurred at room temperature and at low electric fields (< 2 kV/cm). This large effect is enabled by the magnetization reorientation caused by changing the magnetic anisotropy with strain and using multilayered magnetic materials to minimize the internal stress from deposition. This work highlights how multicomponent strain engineering enables enhanced magnetoelectric coupling in heterostructures and provides an approach to realize new energy efficient magnetoelectric applications