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

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

Date: May 2009
Creator: Kallur, Ajay
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 of computer software, in contrast to the conventional mask-based photolithographic approach, in which a photomask must be produced before the device is fabricated. The finished waveguide sensors are evaluated on the basis of their performance as general interferometers. The waveguide developed using the fountain pen-based micro-patterning system is compared with the waveguide developed using the current technique of spin coating method for patterning of upper cladding of the waveguide. The resulting output power profile of the waveguides is generated to confirm their functionality as general interferometers. The results obtained are used to confirm the functionality of the simplified micro-fabrication technique for fabricating integrated optical polymer-based sensors and sensor arrays for chemical/biological sensing applications.
Contributing Partner: UNT Libraries
According to the Goal: How Eliyahu Goldratt Helps Organizations Examine Their Processes to Achieve Maximum Results

According to the Goal: How Eliyahu Goldratt Helps Organizations Examine Their Processes to Achieve Maximum Results

Date: Autumn 2005
Creator: Winter, Christian
Description: Thesis written by a student in the UNT Honors College discussing Eliyahu Goldratt's "Theory of Constraints," summarizes the book "The Goal: A Process of Ongoing Improvement," and examines a company applying this theory.
Contributing Partner: UNT Honors College
Electronic Sound Analysis with Hardware System and Remote Internet Display

Electronic Sound Analysis with Hardware System and Remote Internet Display

Access: Use of this item is restricted to the UNT Community.
Date: August 2010
Creator: McCord, Cameron Forrest
Description: Currently, standards from government agencies such as the National Institute for Occupation Safety and Health exist to aid in safeguarding individuals’ capacity for hearing, but only in factory settings in which large machines often produce loud levels of sound. Neglecting the fact that these preventative measures are only in place in the most limited of settings, no system currently exists to observe and report sound exposure levels in a manner timely or easily recognizable enough to adequately serve its purpose of hearing conservation. Musicians may also incur significant levels of risk for hearing loss in their day-to-day rehearsals and concerts, from high school marching bands to university wind bands. As a result, music school accrediting organizations such as the National Association of Schools of Music and even the European Union have begun taking steps meant to determine the risks associated with music. To meet these goals and improve upon current technologies, a system has been developed that electronically records sound levels utilizing modern hardware, increases the speed of reporting by transmitting data over computer networks and the Internet, and displays measures calculated from these data in a web browser for a highly viewable, user-friendly interface.
Contributing Partner: UNT Libraries
A Real-Time Electronic Sound Analysis System with Graphical User Interface

A Real-Time Electronic Sound Analysis System with Graphical User Interface

Date: August 2011
Creator: Brgulja, Amir
Description: Noise-induced hearing loss is a serious problem common to musical environments. Current dosimetry technology is primarily designed for industrial environments and not suited for musical settings. At present, there are no government regulations that apply to the educational music environment as it relates to monitoring and prevention of hearing loss. Also, no system exists than can serve as a proactive tool in observation and reporting of sound exposure levels with the goal of hearing conservation. Newly proposed system takes a software based approach in designing a proactive dosimetry system that can assess the risk of sound noise exposure. It provides real-time feedback trough a graphical user interface that is capable of database storage for further study.
Contributing Partner: UNT Libraries
Investigation of the feasibility of non-invasive carbon dioxide detection using spectroscopy in the visible spectrum.

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

Date: December 2007
Creator: Marks, Damian
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 using this method on a continuous basis is impractical since it is slow, painful and invasive. Measuring carbon dioxide is critical to preventing ailments such as carbon dioxide poisoning or hypoxia. The problem is, currently there is no known effective non-invasive method for accurately measuring carbon dioxide in the body to properly assess the adequacy of ventilation. The objective of this study was to experimentally use spectroscopy in the visible spectrum and the principles of operation of a pulse oximeter to incorporate a method of non-invasive real-time carbon dioxide monitoring that is as quick and easy to use.
Contributing Partner: UNT Libraries
A Study of the Synthesis and Surface Modification of UV Emitting Zinc Oxide for Bio-Medical Applications

A Study of the Synthesis and Surface Modification of UV Emitting Zinc Oxide for Bio-Medical Applications

Date: May 2009
Creator: John, Sween
Description: This thesis presents a novel ZnO-hydrogel based fluorescent colloidal semiconductor nanomaterial system for potential bio-medical applications such as bio-imaging, cancer detection and therapy. The preparation of ZnO nanoparticles and their surface modification to make a biocompatible material with enhanced optical properties is discussed. High quality ZnO nanoparticles with UV band edge emission are prepared using gas evaporation method. Semiconductor materials including ZnO are insoluble in water. Since biological applications require water soluble nanomaterials, ZnO nanoparticles are first dispersed in water by ball milling method, and their aqueous stability and fluorescence properties are enhanced by incorporating them in bio-compatible poly N-isopropylacrylamide (PNIPAM) based hydrogel polymer matrix. The optical properties of ZnO-hydrogel colloidal dispersion versus ZnO-Water dispersion were analyzed. The optical characterization using photoluminescence spectroscopy indicates approximately 10 times enhancement of fluorescence in ZnO-hydrogel colloidal system compared to ZnO-water system. Ultrafast time resolved measurement demonstrates dominant exciton recombination process in ZnO-hydrogel system compared to ZnO-water system, confirming the surface modification of ZnO nanoparticles by hydrogel polymer matrix. The surface modification of ZnO nanoparticles by hydrogel induce more scattering centers per unit area of cross-section, and hence increase the luminescence from the ZnO-gel samples due to multiple path excitations. Furthermore, surface modification of ...
Contributing Partner: UNT Libraries
Design and validation of an automated multiunit composting system.

Design and validation of an automated multiunit composting system.

Date: December 2009
Creator: Pickens, Mark Everett
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 performed to quantify the effects of degradation on the polymer samples, and the carbon metabolized from the degradation of samples was measured. The second experiment used the AMUCS to determine the effect of synthetic clay nanofiller on the aerobic biodegradability behavior of poly (3-hydroxybutyrate-co-3-hydroxyvalerate).
Contributing Partner: UNT Libraries
Wireless In-home Ecg Monitoring System with Remote Access

Wireless In-home Ecg Monitoring System with Remote Access

Date: August 2012
Creator: Porter, Logan
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 in their home environment while giving health vital information, primarily being the heart’s activity through the ECG, to medical personnel.
Contributing Partner: UNT Libraries
A Study of Laser Direct Writing for All Polymer Single Mode Passive Optical Channel Waveguide Devices

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

Date: May 2008
Creator: Borden, Bradley W.
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 with a loss of less 1dB/cm.
Contributing Partner: UNT Libraries
Piezoresistive Polyvinylidene Fluoride/Carbon Filled Nanocomposites

Piezoresistive Polyvinylidene Fluoride/Carbon Filled Nanocomposites

Date: May 2011
Creator: Vidhate, Shailesh
Description: This thesis examines the value of using dispersed conductive fillers as a stress/strain sensing material. The effect of the intrinsic conductivity of the filler on the ability to be effective and the influence of filler concentration on the conductivity are also examined. To meet these objectives, nanocomposites of polyvinylidene fluoride (PVDF) with carbon nanofibers (CNFs) and carbon nanotubes (CNTs) were prepared by melt-blending using a twin screw extruder. Since PVDF has a potential to be piezoresistive based on the type of crystalline phase, the effect of CNFs on PVDF crystallinity, crystalline phase, quasi static and dynamic mechanical property was studied concurrently with piezoresponse. Three time dependencies were examined for PVDF/CNTs nanocomposites: quasi-static, transient and cyclic fatigue. The transient response of the strain with time showed viscoelastic behavior and was modeled by the 4-element Burger model. Under quasi-static loading the resistance showed negative pressure coefficient below yield but changed to a positive pressure coefficient after yield. Under cyclic load, the stress-time and resistance-time were synchronous but the resistance peak value decreased with increasing cycles, which was attributed to charge storage in the nanocomposite. The outcomes of this thesis indicate that a new piezoresponsive system based on filled polymers is a viable ...
Contributing Partner: UNT Libraries
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