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Full-Text Articles in Engineering

Design And Operation Of A Microwave Flow Cytometer For Single Cell Detection And Identification, Jeffrey A. Osterberg Aug 2022

Design And Operation Of A Microwave Flow Cytometer For Single Cell Detection And Identification, Jeffrey A. Osterberg

All Dissertations

Microwave dielectric sensing has become a popular technique in biological cell sensing for its potential in online, label-free, and real-time sensing. At microwave frequencies probing signals are sensitive to intracellular properties since they are able to penetrate cell membranes, making microwave flow cytometry a promising technology for label-free biosensing. In this dissertation a microwave flow cytometer is designed and used to measure single biological cells and micro particles. A radio frequency (RF)/microwave interferometer serves as the measurement system for its high sensitivity and tunability and we show that a two-stage interferometer can achieve up to 20 times higher sensitivity than …


Synthesis And Characterization Of Glycidyl Methacrylate-Based Graft Copolymer Functional Interfaces, Nikolay Brordinov Dec 2017

Synthesis And Characterization Of Glycidyl Methacrylate-Based Graft Copolymer Functional Interfaces, Nikolay Brordinov

All Dissertations

Modification of materials properties such as surface energy, wettability, ability to absorb, contain or release specific type of chemicals enables practical application of these materials in various scientific and engineering set-ups. However, designing protocol that could be easily adapted for different situations and simultaneously unlock multiple variations of the resulting properties is a non-trivial task. This dissertation is devoted to application of glycidyl methacrylate-based graft copolymers for the purposes of surface modification, establishing fundamental trends and dependencies of this process and exploring the possible range of applications. These materials have extremely valuable property to undergo controllable post-synthetic modifications including surface …


A Device To Record Naturally Daily Wrist Motion, Surya Sharma Dec 2014

A Device To Record Naturally Daily Wrist Motion, Surya Sharma

All Theses

We introduce a new device to record and store wrist motion activity data. The motivation to create this device was the fact that this data can be used to detect periods of eating or the number of bites consumed. There is no similar device available in the market. This device uses new components that have been recently introduced to the market, and newer techniques that can be used for low quantity production. The production cost for this device was $52, similar to other fitness trackers on the market. The device was capable of recording wrist motion activity for 24 hours …


Optical Forces In Nanophotonic Structures, Chenguang Huang Aug 2014

Optical Forces In Nanophotonic Structures, Chenguang Huang

All Dissertations

Nowadays, optical forces are widely used to control or measure the position of micrometer- to nanometer-sized particles, such as living cells, DNA and bacteria. Two major categories of optical forces are discussed here: gradient or dipole force and scattering force. The gradient force is originated from the fact that a polarizable micro-particle placed in a laterally varying optical field will experience different forces in the positively and negatively charged sides. In this thesis, we investigate the optical gradient force in 2D hybrid and plasmonic waveguides. Compared to the conventional dielectric waveguides, we show that the optical force can be enhanced …


Vibration Analysis Of Piezoelectric Microcantilever Sensors, Amin Salehi-Khojin May 2008

Vibration Analysis Of Piezoelectric Microcantilever Sensors, Amin Salehi-Khojin

All Dissertations

The main objective of this dissertation is to comprehensively analyze vibration characteristics of microcantilever-based sensors with application to ultra small mass detection and low dimensional materials characterization. The first part of this work focuses on theoretical developments and experimental verification of piezoelectric microcantilevers, commercially named Active Probes, which are extensively used in most today's advanced Atomic Force Microscopy (AFM) systems. Due to special geometry and configuration of Active Probes, especially multiple jump discontinuities in their cross-section, a general and comprehensive framework is introduced for forced vibration and modal analysis of discontinuous flexible beams. More specifically, a general formulation is obtained …


Incorporation Of Polydiacetylene Sensors Into Commercial Polymers, Jennifer Kauffman May 2008

Incorporation Of Polydiacetylene Sensors Into Commercial Polymers, Jennifer Kauffman

All Dissertations

Polydiacetylenes (PDAs) exhibit a chromatic response to solvents, temperature, strain and other environmental perturbations. When formed in a solid-state polymerization, the backbone of the polymer is planar and continuous π-overlap is observed. However, when the PDA backbone is distorted by an outside force the extended conjugation is interrupted and an optical shift from blue to red occurs. By exploiting the PDAs properties within polymer systems, smart fibers and films have been created that enhance the original intention of the host. Under this umbrella, a strain sensitive polydiacetylene-polyurethane blend was created using 3 and 4-butoxycarbonylmethylurethane PDA and a medical grade polyurethane, …