This work compares the condensation heat transfer and pressure drop for zeotropic refrigerant R-454C and its individual components, R-32 and R-1234yf, in horizontal microfin tubes. One microfin tube has a 4 mm outer diameter, 0.18 mm wall thickness, and a surface area ratio of 1.56. The second tube has a...
The objective of this paper was to measure and compare the heat transfer coefficient and pressure drop of R404A and two potential replacement candidate refrigerants with a lower global warming potential, R448A and R452A. Experiments were conducted inside a 4.7 mm horizontal tube at mass fluxes ranging from 100 to...
Heat transfer coefficients and frictional pressure drop values are experimentally measured during condensation of R134a and its proposed low global warming potential (GWP) replacement, R450A. R450A is a non-flammable zeotropic mixture of R134a and R1234ze (42/58% by mass). Experiments were conducted in a horizontal tube (ID = 4.7 mm) for...
CNTs also offer new opportunities to study new science and develop new technology enabled by their strong electron-electron (e-e) interactions. The lack of dielectric screening inherent in nanoscale structures like CNTs leads to strong e-e interactions, which produce unique physical phenomena. In this thesis, we study the effects of strong...
Exciton-polaritons are a form of light-matter coupling that have potential applications as photonic transistors and logic gates. In order for a photonic transistor or logic gate to be integrated with room temperature fiber-optic technology, excitons-polaritons need to be stable at room temperature and compatible with the red and near-infrared wavelengths...
I investigate the feasibility of a micron-sized biosensor designed to measure neural activity. The circuitry of the biosensor is composed of graphene, some photodiodes, and a light-emitting diode. Many of these biosensors would be injected into a subject’s brain, and when powered by near-infrared light, they would glow in response...
Low-dimensional electronic materials offer a platform to observe biological processes with unprecedented spatial and temporal resolution. Carbon nanotubes (CNTs) are the closest physical analog to an ideal 1D system and can be scaled and integrated into multiplexed electronic circuitry. The molecular structure of a CNT is also biocompatible, making them...
Using a simple dry transfer process, I construct and characterize three nanoscale MoS2 devices using current-voltage curves, Raman spectroscopy, optical and atomic force microscopy. I compare these devices, the thinnest of which was few layer ( ≤ 10 nm) MoS₂ capable of showing photoconductance, with a current whose magnitude is...
As electronics reach nanometer size scales, new avenues of integrating biology and electronics become available. For example, nanoscale field-effect transistors have been integrated with single neurons to detect neural activity. Researchers have also used nanoscale materials to build electronic ears and noses. Another exciting development is the use of nanoscale...
At the macroscopic scale, we have pumps that use the classical laws of physics to move liquids at a well defined rate. In the microscopic world, physicists are exploring pumps that make use of quantum mechanical behavior to build analogous pumps for quantum particles. The importance of such “quantum pumps”...