Digital Commons Network^™

Photonic Crystal-Based Flow Cytometry, Justin William Stewart

USF Tampa Graduate Theses and Dissertations

Photonic crystals serve as powerful building blocks for the development of lab-on-chip devices. Currently they are used for a wide range of miniaturized optical components such as extremely compact waveguides to refractive-index based optical sensors. Here we propose a new technique for analyzing and characterizing cells through the design of a micro-flow cytometer using photonic crystals. While lab scale flow cytometers have been critical to many developments in cellular biology they are not portable, difficult to use and relatively expensive. By making a miniature sensor capable of replicating the same functionality as the large scale units with photonic crystals, we …

Development Of Electroplated-Ni Structured Micromechanical Resonators For Rf Application, Mian Wei

USF Tampa Graduate Theses and Dissertations

On-chip vibrating MEMS resonators with high frequency-Q product on par with that of the off-chip quartz crystals have attracted lots of attention from both academia and industry for applications on sensing, signal processing, and wireless communication. Up to now, several approaches for monolithic integration of MEMS and transistors have been demonstrated. Vibrating micromechanical disk resonators which utilize electroplated nickel as the structural material along with either a solid-gap high-k dielectric capacitive transducer or a piezoelectric transducer have great potential to offer unprecedented performance and capability of seamless integration with integrated circuits.

Despite the frequency drift problems encountered in early attempts …

Low Loss Vhf And Uhf Filters For Wireless Communications Based On Piezoelectrically-Transduced Micromechanical Resonators, Julio Mario Dewdney

USF Tampa Graduate Theses and Dissertations

For the past decade, a great deal of research has been focused towards developing a viable on-chip solution to replace the current state-of-the-art VHF and UHF filters based on SAW and FBAR technologies. Although filters based on SAW and FBAR devices are capable of fulfilling the basic requirements needed for IF and RF bandpass filtering and reference signal generation, an alternative solution that can enable the next generation of multi-frequency and multi-mode transceivers while enabling size and price reduction by allowing the manufacturing of single-chip monolithic RF transceivers is highly desired. In response to these new needs, piezoelectrically-transduced micromechanical filters …

Continuous Electrowetting Actuation Utilizing Current Rectification Properties Of Valve Metal Films, Corey M. Lynch

USF Tampa Graduate Theses and Dissertations

Electrowetting on dielectric (EWOD) is a technique for reducing the apparent contact angle of a fluid droplet, which has many promising applications in the fields of optics, digital displays, and lab-on-a-chip research. In this thesis, a design is presented for a novel single circuit device for achieving continuous droplet motion, by using the current-rectifying properties of valve metals to create diode-like behavior. This contrasts with existing designs, which require an array of individual electrodes to achieve motion in discrete steps. We are able to demonstrate continuous droplet motion across a 28mm-long test strip with an applied voltage of 303 V …

Optimization And Characterization Of Lab-On-A-Chip Elements: Microfluidic Chambers And Microneedles, Puneet Khanna

USF Tampa Graduate Theses and Dissertations

In this work, MEMS based fabrication is used to engineer multifaceted enhancements to microfluidic systems such as lab-on-a-chip devices. Two specific elements of microfluidic systems are the focus of this study: microfluidic chambers and microneedles. Microfluidic chambers, which are back-end passive elements, via proposed material and structural modifications, are shown to exhibit reduced non-specific DNA binding and enable increased cell lysis efficiency. Microneedles, which are front-end interfacing elements, have been fabricated in silicon and in silicon dioxide varieties. The geometry of silicon microneedles has been varied via DRIE processing to yield sharpened tips. Sharpening of microneedle tips provides reduced skin …

Kinematics Of Curved Flexible Beam, Saurabh Jagirdar

USF Tampa Graduate Theses and Dissertations

Compliant mechanism theory permits a procedure called rigidbody replacement, in which two or more rigid links of the mechanism are replaced by a compliant flexure with equivalent motion. Methods for designing flexure with equivalent motion to replace rigid links are detailed in Pseudo-Rigid-Body Models (PRBMs). Such models have previously been developed for planar mechanisms. This thesis develops the first PRBM for spherical mechanisms. In formulating this PRBM for a spherical mechanism, we begin by applying displacements are applied to a curved beam that cause it todeflect in a manner consistent with spherical kinematics. The motion of the beam is calculated …

Development Of A Generic Pda Based Control Mechanism For In-House Fabricated Miniature Sensors, Sunny Kedia

USF Tampa Graduate Theses and Dissertations

A novel method of controlling miniature sensors using Handspring Visor Prism PDA has been implemented. A generic motherboard was developed to map the data and address lines from the Visor onto a Complex Programmable Logic Device (CPLD) to provide basic electrical signals to the sensor board. The sensor board housed the sensor and contained application specific circuitry. The PDA, the motherboard, and the sensor board completed the control mechanism for the sensor. Miniature sensors and PDA based control mechanism scaled down the size of the complete system making the unit portable. This unit facilitated a faster analysis of data on …

A Novel Normal-To-Plane Space Efficient Micro Corner Cube Retroreflector With Improved Fill Factor, Rahul Agarwal

USF Tampa Graduate Theses and Dissertations

A Corner Cube Retro-reflector (CCR) is a device that can be used as transmitters in wireless free space optical communication systems, or remote sensing instruments. A novel approach to fabricate the CCR is developed, where almost 100% of the planar chip area acts as the CCR compared to the maximum of 33% in the prior MEMS CCRs. Unlike the conventional micro machined CCRs that have two planes (mirrors of the CCR) normal to the surface of the wafer, our approach yields all the mirrors within the bulk of the wafer, ensuring very high packing densities and wide acceptance angles. The …