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open access

Micro-fabrication of a Mach-Zehnder interferometer combining laser direct writing and fountain pen micropatterning for chemical/biological sensing applications.

Description: This research lays the foundation of a highly simplified maskless micro-fabrication technique which involves incorporation of laser direct writing technique combined with fountain pen based micro-patterning method to fabricate polymer-based Mach-Zehnder interferometer sensor arrays' prototype for chemical/biological sensing applications. The research provides methodology that focuses on maskless technology, allowing the definition and modification of geometric patterns through the programming … more
Date: May 2009
Creator: Kallur, Ajay
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Study of Laser Direct Writing for All Polymer Single Mode Passive Optical Channel Waveguide Devices

Description: The objective of this research is to investigate the use of laser direct writing to micro-pattern low loss passive optical channel waveguide devices using a new hybrid organic/inorganic polymer. Review of literature shows previous methods of optical waveguide device patterning as well as application of other non-polymer materials. System setup and design of the waveguide components are discussed. Results show that laser direct writing of the hybrid polymer produce single mode interconnects w… more
Date: May 2008
Creator: Borden, Bradley W.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Wireless In-home Ecg Monitoring System with Remote Access

Description: The thesis work details the design and testing of a wireless electrocardiogram (ECG) system. This system includes a wireless ECG device, as well as software packages to visually display the waveform locally on a computer and remotely on a web page. The remote viewing capability also extends to using an Android phone application. The purpose of the system is to serve as a means for a doctor or physician to check up on a patient away from a hospital setting. This system allows for a patient to be… more
Date: August 2012
Creator: Porter, Logan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Design and Validation of an Automated Multiunit Composting System.

Description: This thesis covers the design of an automated multiunit composting system (AMUCS) that was constructed to meet the experimental apparatus requirements of the ASTM D5338 standard. The design of the AMUCS is discussed in full detail and validated with two experiments. The first experiment was used to validate the operation of the AMUCS with a 15 day experiment. During this experiment visual observations were made to visually observe degradation. Thermal properties and stability tests were perform… more
Date: December 2009
Creator: Pickens, Mark Everett
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigation of the feasibility of non-invasive carbon dioxide detection using spectroscopy in the visible spectrum.

Description: Pulse oximeters are used in operating rooms and recovery rooms as a monitoring device for oxygen in the respiratory system of the patient. The advantage of pulse oximeters over other methods of oxygen monitoring is that they are easy to use and they are non-invasive, which means it is not necessary break the skin to extract blood for information to be obtained. The standard for the measurement of partial pressure of CO2 and O2 is an arterial blood gas analysis (ABG). However routine monitoring … more
Date: December 2007
Creator: Marks, Damian
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Computer Virus Spread Containment Using Feedback Control.

Description: In this research, a security architecture based on the feedback control theory has been proposed. The first loop has been designed, developed and tested. The architecture proposes a feedback model with many controllers located at different stages of network. The controller at each stage gives feedback to the one at higher level and a decision about network security is taken. The first loop implemented in this thesis detects one important anomaly of virus attack, rate of outgoing connection. Tho… more
Date: December 2004
Creator: Yelimeli Guruprasad, Arun
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Nodal Resistance Measurement System

Description: The latest development in the measurement techniques has resulted in fast improvements in the instruments used for measurement of various electrical quantities. A common problem in such instruments is the automation of acquiring, retrieving and controlling the measurements by a computer or a laptop. In this study, nodal resistance measurement (NRM) system is developed to solve the above problem. The purpose of this study is to design and develop a compact electronic board, which measures elect… more
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: May 2005
Creator: Putta, Sunil Kumar
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Evaluation of dynamic and static electrical characteristics for the DY8 and YI8 process gallium diodes in comparison to the DI8 process boron diodes.

Description: A rectifier is an electrical device, comprising one or more semiconductor devices arranged for converting alternating current to direct current by blocking the negative or positive portion of the waveform. The purpose of this study would be to evaluate dynamic and static electrical characteristics of rectifier chips fabricated with (a) DY8 process and (b) YI8 process and compare them with the existing DI8 process rectifiers. These new rectifiers were tested to compare their performance to meet … more
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: December 2006
Creator: Dhoopati, Swathi
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

MBE Growth and Instrumentation

Description: This thesis mainly aims at application of principles of engineering technology in the field of molecular beam epitaxy (MBE). MBE is a versatile technique for growing epitaxial thin films of semiconductors and metals by impinging molecular beams of atoms onto a heated substrate under ultra-high vacuum (UHV) conditions. Here, a LabVIEW® (laboratory virtual instrument engineering workbench) software (National Instruments Corp., http://www.ni.com/legal/termsofuse/unitedstates/usH) program is dev… more
Date: May 2006
Creator: Tarigopula, Sriteja
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Electrical resistivity as a measure of change of state in substrates: Design, development and validation of a microprocessor-based system.

Description: Smart structures are relevant and significant because of their relevance to phenomena such as hazard mitigation, structural health monitoring and energy saving. Electrical resistance could potentially serve as an indicator of structural well-being or damage in the structure. To this end, the development of a microprocessor-based automated resistance measurement system with customized GUI is desired. In this research, a nodal electrical resistance acquisition circuit (NERAC) system was designed.… more
Date: December 2009
Creator: Le, Dong D.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Indoor Propagation Modeling at 2.4 GHz for IEEE 802.11 Networks

Description: Indoor use of wireless systems poses one of the biggest design challenges. It is difficult to predict the propagation of a radio frequency wave in an indoor environment. To assist in deploying the above systems, characterization of the indoor radio propagation channel is essential. The contributions of this work are two-folds. First, in order to build a model, extensive field strength measurements are carried out inside two different buildings. Then, path loss exponents from log-distance path l… more
Date: December 2005
Creator: Tummala, Dinesh
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Surface Plasmon Based Nanophotonic Optical Emitters

Description: Group- III nitride based semiconductors have emerged as the leading material for short wavelength optoelectronic devices. The InGaN alloy system forms a continuous and direct bandgap semiconductor spanning ultraviolet (UV) to blue/green wavelengths. An ideal and highly efficient light-emitting device can be designed by enhancing the spontaneous emission rate. This thesis deals with the design and fabrication of a visible light-emitting device using GaN/InGaN single quantum well (SQW) system wit… more
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: December 2005
Creator: Vemuri, Padma Rekha
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Sunlight readability and luminance characteristics of light-emitting diode push button switches.

Description: Lighted push button switches and indicators serve many purposes in cockpits, shipboard applications and military ground vehicles. The quality of lighting produced by switches is vital to operators' understanding of the information displayed. Utilizing LED technology in lighted switches has challenges that can adversely affect lighting quality. Incomplete data exists to educate consumers about potential differences in LED switch performance between different manufacturers. LED switches from four… more
Date: May 2004
Creator: Fitch, Robert J.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Increasing the Dynamic Range of Audio THD Measurements Using a Novel Noise and Distortion Canceling Methodology

Description: The objective of this study was to determine how a new experimental methodology for measuring Total-Harmonic-Distortion (THD) of operational amplifiers functioned when compared with two standard methodologies, and whether the new methodology offers any improvement in noise floor and dynamic range along with distortion canceling of the sine-wave source used in the testing. The new methodology (THD) is being tested against two standard methodologies: Spectral Analysis using a tuned receiver type … more
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Date: May 2003
Creator: Dunipace, Richard Alan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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