Dr Harry Fred Tibbals III

[Dr Harry Tibbals III]

Research Associate, Materials Science and Engineering
Last Updated: October 24, 2021
about me

Research Interests

Research Interests
Characterization of biomaterials

Research Keywords

Research Keywords
materials characterization, bionstrumentation, analytical chemistry, biomaterials, biomedical devices, sensors

Teaching Interests

Teaching Interests
Natural nanomaterials and biomaterials



Harry F. Tibbals is a Research Professor in Materials Science and Engineering at UTA since 2011. He was Director of the Bioinstrumentation Center at UTSW for the prior 14 years. Before joining UTSW, he was founder and president of Biodigital Technologies, Inc., serving as a consultant and contract manager for projects developing biomedical, environmental, analytical, and control instrumentation from 1990 to 1997. During the 1980's he held positions with Rockwell International, United Technologies, and Inmos Ltd. developing and managing projects for advanced computer and semiconductor control, imaging and sensor networks. During the 1970s he taught and did research at the Universites of Leicester, Glasgow, Durham, and North Texas, and the UK's Open University, working on instrumentation, computer networks , and application development for engineering, medical , scientific, environmental, and linguistic research. He earned the PhD Degree in Chemistry at the University of Houston in 1970, and was awarded an SRC Postdoctoral Fellowship at the University of Leicester for research in the physical chemistry of silicon. He earned a double Bachelor of Science degree in Chemistry and Mathematics at Baylor University in 1965, where he was an undergraduate research assistant in electrochemistry and President of the American Chemical Society Student Chapter. His high school and elementary education was in East Texas and at C. E, Byrd High School in Shreveport, Louisiana. He has served in various work for a number of charitable, environmental, and civic organizations, including working groups of the North Texas Commission, Communities in Schools, The American Foundation for the Blind, and others. He serves on NIH Review Panels and has been a reviewer for NSF and a number of scientific publications.



    • 1970 PhD in Chemistry and Mathematics
      University of Houston, Houston, Texas
    • 1965 BS in Chemistry and Mathematics
      Baylor University


    • 1977 to Present Institute of Electrical and Electronic Engineers
      Chapter President (Consultants Network), Chapter Senior Member, Treasurer (EMBS), Chapter Sectretary (EMBS), Symposium Chair (EMBS)
      he Institute of Electrical and Electronics Engineers (IEEE) is a professional association for electronic engineering and electrical engineering (and associated disciplines). IEEE is the world’s largest technical professional organization. IEEE's core purpose is to foster technological innovation and excellence for the benefit of humanity.
    • Jan 1967 to Present Society of the Sigma Xi
      Sigma Xi: The Scientific Research Society is a non-profit global, interdisciplinary society that promotes ethics and excellence in science and research, an honor society for scientists and engineers. Activities include grants in aid of research and publication of American Scientist journal.
    • Sept 1964 to Present American Association for the Advancement of Science
      The American Association for the Advancement of Science (AAAS) is an American international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the betterment of all humanity. It is the world's largest general scientific society.
    • Sept 1963 to Present American Chemical Society
      President, Student Chapter, Baylor University 1963-5

Support & Funding

Support & Funding



    • October  2016
      Tibbals, HarryF. (Author & Presenter), "Non-Invasive Characterization of Collagen and Related Biological Structural Materials by IR and Raman Spectroscopy", UT Arlington Department of Materials Science and Engineering, UT Arlington Nedderman Hall 203. (October 28, 2016).
    • September  2015
      Tibbals, HarryF. (Author), "From Medical Nanotechnology and Nanomedicine to Precision Medicine: The Role of Advanced Materials", UT Arlington Materials Science and Engineering, UTA Engineering, Nedderman 202 (https://www.uta.edu/enews/trailblazer/2015/09/22.php). (September 25, 2015).
    • April  2015
      Tibbals, HarryF (Author & Presenter), "Nanotechnology: Opportunities in an Emerging Field", Eastfield College, Eastfield College, Dallas, TX. (April , 2015).
    • July  2013
      Tibbals, HarryF (Panelist), "Acceptance Acknowledgement: IEEE EMBS in Dallas Activities and Achievements", IEEE Engineering in Medicine and Biology Society, Osaka, Japan. (July 3, 2013).
    •  2012
      Tibbals, HarryF (Author), Meletis, Efstathios (Author), Smith, AdamJ. (Author), Eberhart, Robert (Author), Zimmern MD, P. (Author & Presenter), "Microstructural and micromechanical studies of surgical mesh materials: FTIR and RAMAN", European Association of Urology, Paris, France. ( , 2012).
    • June  2012
      Cao, H. (Author), Landge, V. (Author), Thakar, S. (Author), Rao, S. (Author), Hsu, L.C. (Author), Tang, S.J. (Author), Spechler, S.J. (Author), Tibbals, H.F. (Author), Chiao, Jung-Chih (Author & Presenter), "Remote detection of gastroesophageal reflux using an impedance and pH sensing transponder", IEEE MTT, Montreal, Quebec, Canada. (June 18, 2012).
    • April  2012
      Tibbals, HarryF (Author & Presenter), "Wireless MEMS Sensing for Biomedical Physiology", University of Texas at Dallas, Department of Physics, Prof. Robert Glaser, Chair, University of Texas at Dallas, Richardson, TX. (April , 2012).
    • December  2011
      Tibbals, HarryF. (Panelist), Lacko, Andras (Panelist), Hughes, Gareth (Panelist), Cappelleti, Pat (Moderator), Merkle, DeniseLynn (Coordinator/Organizer), "Nanomedicine: Devices, Materials, and Technologies", Fort Worth Life Sciences Coalition, with Sponsors: Porous Metal Products, Fresnel Technologies, with support from Alcon, UNT Health Sciences Center, Medical Nanotechnologies, Inc., UT Southwestern, A5A Center (Arts 5th Avenue), Fort Worth, Texas, USA. (December 14, 2011).
    • September  2011
      Smith, A.J. (Author), Meletis, Efstathios (Author), Eberhart, R., Zimmern, P. (Author & Presenter), Tibbals, H. (Author), "Microstructural and Micromechanical Studies of Surgical Mesh Materials: Mechanical", International Continence Society (ICS), University of Glasgow, Scotland, UK. (September 1, 2011).
    • June  2011
      Tibbals, HarryF. (Author & Presenter), Chiao, Jung-Chih (Author), Hsu, Wei (Author), Tang, S.J. (Author), Word, R.A. (Author), Buerger, S. (Author), "Progress in wireless MEMS pressure sensing for novel biomedical applications", NSF National Science Foundation, The Electrochemical Society, Hellas Foundation for Research and Technology, Demokritos National Center for Scientific Research, UTA, University of Patras, University of Crete, Karlsruhe Institute of Technology, Hersonissos, Crete, Greece. (June 28, 2011).
    • May  2011
      Tibbals, H.Fred (Co-Chair), Hao, Yaowu (Co-Chair), "Bioinstrumentation/MEMS: Nanotechnology", NSF: National Science Foundation; Additional Support from: Alcon, Healthpoint Biotherapeutics, Plexon, St. Jude Medical, Texas Instruments, UT Dallas, UT Southwestern, UT Arlington, UT Arlington. (May 1, 2011).
    • March  2011
      Manandhar, S. (Author), D'Souza, N. (Author), Robertson, L. (Author), Eberhart, R. (Author), Tibbals, H.F. (Author), Zimmern, P. (Author & Presenter), "Strength and Degradation Characteristics of Biodegradable Polymer Fibers and Electrospun Structures During Short Term Saline Immersion", SUFU - Society for Urodynamics and Female Urology, Phoenix, AZ, USA. (March 2, 2011).
    • September  2010
      Tibbals, Harry (Author & Presenter), "Paradigm Changes in Use of Nanoscale Sensors to Monitor Human Health/Behavior", NSF: National Science Foundation, NSF, Stafford I, (Board Room), 4201 Wilson Boulevard, Arlington VA 22203. (September 20, 2010).
    • April  2010
      Gillean, CynthiaAnn (Author & Presenter), Tibbals, H.F. (Author & Presenter), "Nanoscience as a Unifying and Motivational Theme in K-12 Science Education", Rice University Smalley Institute, Lockheed Martin, Rice University, Houston, Texas, USA. (April 9, 2010).
    • February  2010
      Hsu, H.S. (Author), Huang, W.D. (Author), Tang, S.T. (Author), Spechler, S. (Author), Tibbals, H.F. (Author), Chiao, J.C, (Author & Presenter), "Nanofabricated Sensing Electrodes in a Batteryless Endoluminal Sensing Telemeter for Diagnosis of Gastroesophageal Reflux Disease (GERD), ", ASME: American Society of Mechanical Engineers, Houston, Texas, USA. (February 7, 2010).
    • July  2009
      Tibbals, H.F. (Author & Presenter), Chaney, R. (Author), Hornyak, G.L. (Author), "Natural Nanomaterials: Recent and Potential Medical Applications", NSF: National Science Foundation, ECS: The Electrochemical Society, University of Aegean, UT Arlington ARRI, Agilent Technologies, Rhodes, Greece. (July 1, 2009).
    • October  2006
      Tibbals, HarryFred (Author & Presenter), Sager, Melissa (Other), "Theoretical Investigation of Interaction of Tissue and Implants with Electromagnetic Stimulation in the Radiofrequency Range", University of Texas at Dallas, University of Texas at Dallas. (October 18, 2006).
    •  2003
      Tibbals, H.F. (Author & Presenter), "Aspects of radio frequency telemetry in medical devices and medical research", IEEE Communications Society - CVT, Richardson, Texas. ( , 2003).
    • July  2003
      Tibbals, Harry, "Future Applications of Nanotech in Biomedicine and Environmental Technology", NSF: National Science Foundation, Brookhaven Community College, Dallas, Texas . (July 29, 2003).

Students Supervised

    • Present
      Dissertation Committee Member
      Wisnau Boonrwad, (Material Science and Engineer)
      Plasma electrolytic surface modification of titanium for biocompatability
    • 2021
      Doctoral Comprehensive Exam Committee Member
      Wisnau Boonrawd, (Material Science and Engineer)
      Plasma electrolytic surface modification of titanium for biocompatability
    • Aug 2021
      Dissertation Committee Member
      Kamal Awad, (Material Science and Engineer)
      Nanosilicate composite scaffolds for enhancement of cell growth and biomaterial formation in bone reconstruction
    • May 2020
      Dissertation Committee Member
      Amirali Nojoomi, Shape-morphing three-dimensional (3D) surfaces capable of adopting different geometries have applications in diverse areas such as robotics, biomedicine, optics, and microfluidics. Form the formation of the leaves and flowers to the shaping of complex organs like the brain, and even movement of tissues, the analogues of such shape-morphing 3D surfaces are abundant in nature. However, since the formation of such surfaces in biological systems is fundamentally different from that of human-made materials, replicating their complex morphologies, movements, and thereby functions remains a challenge. Living organisms use controlled patterns of expansion and contraction in their tissues to achieve intricate three-dimensional (3D) morphologies and motions. Inspired by this mechanism, we introduce a method, named digital light 4D printing (DL4P), that encodes phototunable, temperature-responsive 2D hydrogels with spatially and temporally controlled growth (expansion and contraction) to create 3D surfaces with programmed 3D shapes and motions. Taking advantage of a similar shaping approach, DL4P offers the creation of artificial 3D surfaces with the morphology and motion complexity of living organisms. ... High throughput fabrication and on-demand shape morphing combined with high
      mechanical properties, geometrical complexity, and multi-material printing capability offer a new strategy to address the issues and complement the current 3D manufacturing methods. (Material Science and Engineer)
      Single Step Fabrication of Shape Morphing 3D Surfaces
    • Oct 2019
      Doctoral Comprehensive Exam Committee Member
      Rahmani Hooman , Comprehensive Examination: Addition of corrosion inhibitors, in very small amounts, is one of the most effective preventing methods especially for protection of closed water systems through the interaction of the inhibitor’s molecules with the metal surface leading to corrosion rate reduction. Supercomputing and data center facilities are employing water-cooling systems where a Cu plate with Cu water channels and fins is attached to central processing unit (CPU), for heat dissipation. The Cu fins are sandwiched between two Cu plates and are brazed using Cu-Ag eutectic. This is a system that is emerging as the most viable technology for this industry. ... Even with exercising various corrosion protection strategies including the use of benzotriazole (BTA) for inhibition, corrosion is not prevented, and the inhibitor is not highly effective in protecting the device. ... This study is going to investigate the involved mechanisms for the failure of such systems and study the interaction of Cu-Ag alloy with BTA in DI water under different conditions. Based on the prevailing mechanism, it also explores the features of an alternative inhibitor/the combination of inhibitors for a better corrosion protection. (Material Science and Engineer)
      An Investigation on the Corrosion Inhibition of Brazing Cu-Ag Alloy
    • May 2019
      Dissertation Committee Member
      Randall Kelton, Metals have long been known to change their surface topology when subjected to a plastic strain. Given that a plastic zone exists at the tip of a propagating crack, it would seem natural to quantitatively study surface topology changes associated with nucleating and propagating fatigue cracks. So far the workers in this study have only found one measurement of the surface topology changes associated with a nucleating crack. The current research seeks to study and refine, a possible correlation between crack growth and surface topology changes, with the object to develop a damage index for fatigue cracking from surface topology measurement.
      KELTON-DISSERTATION-2019.pdf (3.028Mb) (Material Science and Engineer)
      Investigation of the Surface Topology Changes Associated with Fatique
    • Dec 2018
      Dissertation Committee Member
      Po-Cheng Lu, This dissertation presents four different electrical measurement techniques to detect structural defects in Al/SiO2 interconnects.
      https://rc.library.uta.edu/uta-ir/handle/10106/27770 (Material Science and Engineer)
      Study of Conduction Behavior in Dielectrics in Chip Level Interconnects: Detection of Defects in Al/SiO2 Interconnects
    • June 2018
      Graduate Supervised Research
      Meet Yagnesh Shah, Thesis completed for MS Degree. Bone disorders and disease are associated with multiple factors. Some of the disorders and diseases are difficult to understand because of their unknown root causes. Our goal was to differentiate between normal and genetically modified rat bone ...

      (Material Science and Engineer)
      Characterization of Normal and Abnormal Bones by RAMAN Spectroscopy: Analysis of Mineral to Matrix Ratio of Bone Using Advanced Materials Characterization Techniques
    • June 2018
      Graduate Supervised Research
      Sunil Balasaheb Yadav, This thesis focuses on the characterization of bone with the help of Fourier Transform Infrared Spectroscopy and Energy Dispersive Spectroscopy. Such analysis of the physics and chemistry of biomaterials is vital to resolve problems in life sciences ... (Material Science and Engineer)
      Quantitative Analysis of Mineral/Matrix to Evaluate Genetically Altered Bone with Infrared Spectroscopy and X-Ray Spectral imaging
    • May 2018
      Master's Thesis Committee Member
      Ninad Vilas Khadse, Modern methods of fabricating three-dimensional (3D) objects include sheet metal forming, thermoforming, and additive manufacturing among others. These methods have their own advantages and disadvantages regarding scalability, customizability, and time efficiency. A promising approach is to program the growth (expansion and contraction) of hydrogel sheets to form 3D structures. The differential growth-induced 3D shaping approach has the advantages of traditional manufacturing (scalability) and additive manufacturing (customizability). The objective of this study is to create nanocomposite 3D structures that are stable in ambient environment using the growth-induced 3D shaping approach. This study determines the effect of silica nanoparticles in hydrogels on the shape forming capability to build 3D structures of silica nanocomposites. The drying process of nanocomposite hydrogels at the shrunk state leads to air-stable 3D structures. The mechanical properties of the resulting 3D structures are comparable to those of polymer structures fabricated by conventional additive manufacturing methods. ...
      KHADSE-THESIS-2018.pdf (2.026Mb) (Material Science and Engineer)
      Fabrication of Solid Polymeric 3D Shapes from Programmable Flat Hydrogel Sheets
    • May 2018
      Dissertation Committee Member
      Ami Atul Shah, Supervising Committee;
      Silica is used in various industries, ranging from automobile industry for tires to semiconductor industry, paints and coatings, biomedical devices & applications to food & drug industry. The current processing techniques for precipitated silica involve harsh conditions like high temperature and extreme pH conditions. Nature already has highly evolved production techniques for silica. They run at physiological conditions and exhibit intricate control over the synthesis, leading to very pure and ornate siliceous structures. These structures exhibit organized architecture at scales as small as nano-dimensions. The proposed research work is a step, towards development of new techniques that bio-mimic the silica production where they can be scaled up for industrial productions.
      SHAH-DISSERTATION-2018.pdf (7.499Mb) (Material Science and Engineer)
      Nature Inspired Technology: A New Process For Silicification based on Marine Sponges
    • May 2018
      Dissertation Committee Member
      Anna Zaman, The present-day industry demands development of coatings for harsh environmental applications which can resist impact and oxidation at high temperatures. It is vitally important to develop new hard (>30 GPa) protective coatings which will be thermally stable at temperatures, T > 800 °C and simultaneously will ensure a good protection of the substrate against oxidation from an external atmosphere.
      http://hdl.handle.net/10106/27485 (Material Science and Engineer)
      Investigation of the Processing-Structure-Property Relationship in Ti-Si-N Nanocomposite Coatings
    • May 2018
      Graduate Supervised Research
      Venkata Kandadai, Non-Thesis Research Project: Application of Raman and FTIR spectroscopy to analyze the changes in various fibers under stresses, subjected to oxidation and UV degradation. Developed a novel fixture for the FTIR and RAMAN spectral microscope to measure changes in molecular configuration with precision stress loading of fibers and webs, collagen, etc. Fibers and webs studied included cotton, linen, silk, and synthetic polymers, with various treatments and blends (included surgical meshes).

      (Material Science and Engineer)
      Application of Raman and FTIR Spectroscopy to Analyze the Changes in Cellulosic Fibers
    • May 2018
      Graduate Supervised Research
      Yashashvi Lachagari, FTIR and RAMAN spectroscopy are studied as versatile techniques for evaluating the UV and oxidative stability of edible oils and for providing information on the degradation degree of an oil sample in a simple, fast and accurate way. Oils analyzed included vegetable cooking oils, coconut oil, sunflower oil, ghee, cod liver oil, almond oil, and soybean oil. Oils were analyzed before and during exposure to air and UV under measured conditions and time periods. Changes in absorption peaks were identified. (Material Science and Engineer)
      Analysis of Degradation of Edible Oils with UV and Oxidation Exposure by FTIR and RAMAN Spectroscopy
    • Jan 2017
      Dissertation Committee Member
      Patricia Aracelly Rodriguez-Salazar, This dissertation presents experimental observations that may assist the understanding of electromigration (EM) failure mechanism active in Cu wire and Al thin film pad (wire bond). This study is motivated by an ongoing industrial effort to adapt Cu as wire bonding material for interconnection. Traditional material used for the wire bond has been Au; however, its high cost combined with its susceptibility to reliability failure caused by excessive growth of IMCs (IMC) makes Cu to be an attractive replacement. Though, since an application of Cu to wire bond technology is relatively new, many of reliability failure mechanisms are unknown especially the ones related to EM reliability as it is increasingly serious in limiting useful life of wire bond. This makes the investigation on EM failure mechanism in Cu to be necessary. One of the most challenging difficulties of EM study is the isolation of the EM from any other effects on the failure process such as an increase in temperature by Joule heating. The Joule heat effect is of particular concern because it is expected to be considerable at wire bond configuration, making failure by EM to proceed concurrently with other failure mechanisms. Our investigation then begins with design of test structure that can prove that wire bond failure is indeed induced by EM, and progresses towards understanding microscopic mechanism by which wire bond becomes failure prone by EM. ...
      RODRIGUEZ-SALAZAR-DISSERTATION-2016.pdf (16.20Mb) (Material Science and Engineer)
      Electromigration Induced Interface Reaction in Cu-Wire / Al-Pad Diffusion Couple
    • Sept 2015
      Dissertation Committee Member
      Dong Liu, This study aims at developing a promising alternative approach to utilize solar energy continuously with high efficiency by employing photocatalytic vanadium redox reactions to overcome major drawbacks associated with conventional photoelectrochemical water splitting. The preliminary study was implemented on TiO2 and WO3/TiO2 by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and zero-resistance ammetry (ZRA) in a photoelectrochemical cell (PEC). The results show much enhanced photoelectrochemical response with the assistance of vanadium(IV, VO2+) redox species. Such photoresponse improvement is attributed to the hole scavenging effect by fast vanadium redox reaction to depress charge recombination at semiconductor/liquid interface in both TiO2 and WO3/TiO2 cases. Facilitated electron transfer from WO3 to TiO2 further contributes to the photoresponse of WO3/TiO2 hybrid electrode due to their band structures interplay. During the study, a unique photocharging/discharging process was discovered and modeled on WO3-based hybrid electrodes due to the formation/decomposition of hydrogen tungsten bronze (HxWO3) from WO3 under AM 1.5 illumination in highly acidic environment. Comparison of electrochemical impedance spectroscopy (EIS) results on TiO2 and WO3/TiO2 electrodes indicates that vanadium redox species, due to their fast electrochemical kinetics, not only enhance the photocurrents under illumination, but also help release reversely the stored electrons under dark through decomposition reaction of HxWO3.To further improve photocatalytic property of the PEC, the conventional H2SO4 was replaced with a novel supporting electrolyte, methanesulfonic acid (MSA) as a simple but feasible optimization measure. CV, zero-resistance ammetry (ZRA) and conductivity measurements demonstrate its excellent chemical stability, high conductivity and superior photoelectrochemical performance over H2SO4, especially when vanadium redox species were involved in the electrolyte.
      Liu_uta_2502D_13231.pdf (4.322Mb) (Material Science and Engineer)
      Studying An All-vanadium Photoelectrochemical Cell For Highly Efficient Solar Energy Conversion And Storage Via Photocatalytic Redox Reaction
    • Sept 2015
      Master's Thesis Committee Member
      Ronaksinh Parmar, Any material containing a crack when subjected to a certain amount of load, will eventually fail. This failure of material can be either time consuming (ductile) or instant (brittle) depending on the type of material and amount of load applied. For one to be able to study fracture toughness, it is important to study the material's failure rate and how long it can withstand load without failure once a crack has been initiated. Ductile materials demonstrate high fracture toughness while brittle materials show lower fracture toughness and fail instantly once a crack has been initiated. Characterization of fracture toughness in bulk materials is easy and well established. However, it becomes difficult when dealing with brittle thin films. As the coating thickness decreases below ~1 μm, it becomes increasingly difficult to evaluate fracture toughness using conventional methods. Bulk materials can also be machined easily for making test specimen but Diamond like Carbon (DLC) thin films cannot be synthesized in bulk. Micro and nano-indentation techniques are proposed for cases where conventional tension test and impact test fails to evaluate fracture toughness. Indentation techniques are very well developed for hardness measurement in all types of materials. This paper is focusing towards characterization of fracture toughness in brittle (100) single crystal Silicon (Si) and DLC films coated on Si substrate. Such DLC thin films are designed to enhance thermal, oxidation, corrosion and mechanical resistance of substrate materials. Though sometimes service lifetime of such coatings in applications is limited by their fracture resistance or fracture toughness. Indentation is an easy, inexpensive, and non-destructive method for mechanical characterization for small volume of material. Such indentation is made using three sided or four sided diamond tip like, Vickers and cube-corner. Fracture toughness can be evaluated by analyzing the radial cracks formed by this indentation. Presence of DLC coating reduces the radial crack length compared to crack length observed in uncoated Si. Different indentation models are used for characterization of fracture toughness in DLC thin films and Si wafer. It is found that the strain energy release model is most appropriate for evaluating fracture toughness in these films. The most challenging part of this research was to understand the effect of substrate on thin films and a way to evaluate the fracture toughness of thin films without the influence of substrate material.
      Parmar_uta_2502M_13320.pdf (1.838Mb) (Material Science and Engineer)
      Characterization Of Fracture Toughness In Amorphous Diamond Like Carbon Thin Films And Coatings
    • Aug 2015
      Dissertation Committee Member
      Yishu Wang, In this body of work, the examination of three different types of Strontium doped lanthanum manganite thin films synthesized by magnetron sputtering in the Surface and Nano Engineering Laboratory (SaNEL) allowed for the development of a detailed understanding between the processing conditions, the nano-scale structure and strain relaxation of the as-deposited thin films. Pure Lanthanum manganite and strontium doped lanthanum manganite thin films which were epitaxially grown on (001) single crystalline lanthanum alumina (LAO) and magnesium oxide (MgO) were fabricated by using single target deposition. The optimum deposition conditions were explored as preparation for synthesis epitaxial composition gradient strontium doped lanthanum manganite thin films by using co-sputtering deposition later. Surface morphology and microstructure of as-deposit thin films were characterized by atomic force microscopy (AFM), x-ray diffraction (XRD) and high resolution transmission electronic microscopy (HRTEM). Pseudo-cubic structure was identified in epitaxial lanthanum manganite thin film on LAO and strontium doped lanthanum manganite on MgO substrate, while orthorhombic structure was obtained in epitaxial strontium lanthanum manganite on LAO and lanthanum manganite on MgO substrate. Deposition rates of each target on different substrate were calculated. ECG strontium doped lanthanum manganite thin films were prepared on the same substrates by using co-sputtering deposition with both targets deposited simultaneously. The as-deposit thin films using novel deposition procedure with different conditions were compared. The substrate temperature and power rate of each target are considered as the key factor for controlling the quality of the films.
      Wang_uta_2502D_13279.pdf (6.774Mb) (Material Science and Engineer)
      Comprehensive Study Of Composition Gradient Strontium Doped Lanthanum Manganite Thin Films Deposited By Magnetron Co-sputtering
    • May 2015
      Dissertation Committee Member
      Cuong Manh Nguyen, Multi-electrode array (MEA) has emerged as one of the most important and common tools to monitor physiological and biological signals. Advanced micro-electro-mechanical systems (MEMS) and innovative nanofabrication
      Nguyen_uta_2502D_13051.pdf (5.670Mb) (Electrical Engineering)
      Design And Fabrication Of Iridium Oxide-based Multi-electrode Array For Biomedical Applications
    • May 2015
      Master's Thesis Committee Member
      Suo Liu, Titanium Silicon Nitride has received much attention in recent years for its theoretical super hardness and oxidation resistance at high temperature. In this work, the mechanical properties of TiSiN thin films including hardness, coefficient of friction, wear rate, wear mechanism were studied in detail using nanoindentation, pin-on-disk tribometer, optical profilometer, SEM and XPS. Four deposition conditions were varied to find the optimal conditions that produce the TiSiN film with the highest hardness and the best wear resistance. First, four substrate biases (100V, 200V, 300V, and 500V) were used, respectively. Then, different power (50W, 55W, 60W) and different N2 ratio (20%, 25%) were applied to Si target. Finally, three rotation speeds of the substrate holder (1RPM, 3RPM, and 6RPM) were utilized. Our study results demonstrated that TiSiN coating deposited at 100V bias, 60W Si power, 25%N2 gas mixture, and 6 RPM rotation speed has the highest hardness of 38.9GPa. High COFs of greater than 1.0 were observed in all films tested. Wear rates decreases as the hardness of the film decreases. The wear mechanism was assumed to be a three body wear due to the presence of counter material debris in the wear track.
      Liu_uta_2502M_13124.pdf (2.829Mb) (Material Science and Engineer)
      The Effects Of Deposition Conditions On The Mechanical Properties Of Titanium Silicon Nitride Nanocomposite Coatings
    • Dec 2014
      Master's Thesis Committee Member
      Soundarya Pondichery, Corrosion causes deterioration of a material due to its environment. Corrosion control has been one of the biggest challenges in most industries since many years. There are various notable and unknown factors that influence the rate of corrosion of a certain material/environment system. Magnetic fields and their driven effects on an electrochemical system has been recently gained interest. Various magnetic field driven forces occurring in an electrolyte have been reported during an electrochemical reaction. Lorentz force driven convection in the electrolyte, known as MHD effect and paramagnetic gradient forces are reported to be the most effective. This research studies the effects of an external magnetic field on the electrochemical nature of materials in 3.5% NaCl solution. To understand and analyze magnetic field effects on a wide range of materials, both ferromagnetic and non-magnetic materials which are active, active-passive type are studied in near sea water solution i.e. 3.5% NaCl solution. Potentiodynamic polarization and corrosion potential vs time tests were carried out to study and analyze corrosion behavior in 3.5% NaCl solution. Corrosion tests results were obtained both with and without the influence of an external magnetic field of 0.75T. On comparing the electrochemical analysis results of both conditions in 3.5% NaCl solution, it clearly depicts the effect of an external magnetic field on the corrosion potential and corrosion rate. In the case of ferromagnetic materials like 416 SS and 1018 carbon steel, a cathodic shift of the corrosion potential and increase in the corrosion rate was observed. While for ferrous but non-magnetic and passivating material like 304 SS, no effect of the magnetic field was observed which can be attributed to its non-magnetic austenitic phase and highly stable oxide formation tendency. Also, no effect was observed on the non-ferrous alloys like Ti alloy (Ti6Al4V) and Zn due to not only because of diamagnetic nature of its ions but also of its actively passivating and dissolution nature respectively. On comparing the SEM micrographs taken post each experiment to study the surface morphology, it confirmed the increased corrosion activity on 416 SS and 1018 carbon steel and no effect on 304 SS, Ti and Zn.
      Pondichery_uta_2502M_12979.pdf (3.490Mb) (Material Science and Engineer)
      A Study On The Effect Of Magnetic Field On The Corrosion Behavior Of Materials
    • Sept 2014
      Dissertation Committee Member
      Farzad Sarker, Bone fracture is a common health risk for older people suffering from bone disease like osteoporosis. The more severe the osteoporosis is the more structural degradation in bones occurs, which eventually makes bones more fracture prone. The mechanical behavior of bone depends on the structural response of bone constituents over a broad range of length scales spanning from the nanoscale collagen fibril level to the macroscale trabeculae level. As such, in order to understand bone fracture, it is important to know the structure-property relations of bone material over the entire length of scale. Surprisingly, a quantitative understanding of bone fracture toughness is still not well understood, which the premise of the current study is. The multiscale analysis of bone is performed by considering five distinctive microstructures of bone, namely, the nano scale, submicron scale, micron scale, macro scale and trabecular bone itself. These substructures span almost over 9 order of length scales. By considering the nanoscale collagen fibril, the building block of bone composed of collagen protein (TC) and hydroxyapatite (HAP) mineral crystal, as a discontinuous fiber reinforced composite structure, the Halpin-Tsai relation for discontinuous fiber reinforced composites were used as the initial process for calculating mechanical properties of HAP and TC in nano scale. From the hierarchical level 2 to level 5, a self-similar approach was used to determine the mechanical properties of subsequent microstructures. Then, these properties were applied on several finite element models consisting of several fully three dimensional solid trabecular model (obtained from direct micro CT scan) and five different "approximated spongy" microstructures with appropriate boundary conditions. Each approximated model represents a simplified microstructure of the trabecular network. Critical stress intensity factor or fracture toughness was calculated from linear elastic fracture mechanics theories using the constitutive model developed from multi-scale analysis. The effects of trabecular thickness on Mode I fracture toughness were studied with different models of different thickness and their relations were analyzed. A comparative study of structural stiffness and anisotropy was conducted between the CT scan image based real bone microstructure and approximated simplified bone like microstructures. Finally, a 3D printing based manufacturing method was adopted to fabricate and characterize SiC nanoparticle reinforced nanocomposites using the micro CT image we studied. The stress-strain response was measured and deformation mechanism was studied.
      Sarker_uta_2502D_12805.pdf (7.044Mb) (Mech and Aero Engineering)
      Degradation Mechanics Of Bone And Bone Like Materials Via Multiscale Analysis
    • Sept 2014
      Dissertation Committee Member
      Young-Sik Seo, This work proposed an integrated circuit (IC) design that provides the required functionality for a wireless, batteryless implant. For biomedical applications, the physiological signals can be detected if the parameter of interest can be converted to a change in electrical parameters such as capacitance, resistance or an amperometric signal. The implantable transponder is suitable for sensors that generate one of the aforementioned analog signals. In the proposed universal platform, a voltage-controlled oscillator (VCO) was used to detect variations of voltage or current. Similarly, a relaxation oscillator (RO) was used to detect changes in capacitance or resistance. Thus, the VCO and the RO were integrated in a single chip, thereby providing the capability to transduce all of the possible analog signals into frequencies. To minimize mutual interferences that can occur when multiple sensors are in operation, a multiplexer (MUX) was employed to isolate the operation of the oscillators.
      Seo-uta-11682.pdf (6.944Mb)17 (Electrical Engineering)
      An IC design for wireless batteryless multi-sensing platform for biomedical applications
    • Aug 2014
      Doctoral Comprehensive Exam Committee Member
      Adam J. Smith, Electrolytic Plasma Processing (EPP) is an emerging, clean surface modification technology which is able to both clean and, depending on the circuit polarity, deposit either cationic or anionic species from an aqueous electrolyte. EPP offers several benefits including environmental cleanliness, high deposition rates, and a nanograined surface structure. The following work presents research conducted on EPP, including surface cleaning of Fe and deposition of Ni onto Fe and Al substrates. Investigations were made into the microstructure of the surface as well as the atomic compositions of the coating and coating/substrate interface. ... (Material Science and Engineer)
      Surface modification of iron and aluminum by electrolytic plasma processing
    • July 2014
      Master's Thesis Committee Member
      Anna Zaman, Tantalum Nitride is chemically inert, oxidation resistant and hard. TaN finds its application as a protective coating on steel due to their excellent wear properties. It has become a very promising diffusion barrier material in Cu interconnect technology in microelectronics. TaN has not been analyzed as much as other transition metal nitrides like the TiN system because TaN exhibits various stable and metastable phases. The emergence of these phases and the different physical, chemical and mechanical properties depend on the growth technique and deposition conditions. TaN thin films were deposited using the magnetron PVD system in the SaNEL lab. The aim of this study was to identify the effect of processing parameters like N2/Ar ratio, substrate bias and temperature, on the emergence of the different phases present in TaN thin films and the effect of deposition conditions on the mechanical properties of these films. The phases present in the films, deposited at varying conditions were explored via low angle X-Ray Diffraction (XRD), hardness of the films was measured by Nanoindentation and tribological tests were carried out to measure the frictional and wear behavior. It was observed that at high percentage of Nitrogen (10%-25%) the main phase present was FCC TaN and as the nitrogen content was decreased a mixture of phases was present in these films. The hardness of the films increases as we decrease the Nitrogen content, yielding a film with a hardness of 37.1 GPa at 3% N2 with a substrate bias voltage of -100 V.
      Zaman_uta_2502M_12629.pdf (1.695Mb) (Material Science and Engineer)
      Characterization Of Tantalum Nitride Thin Films By Magnetron Sputtering
    • Mar 2014
      Master's Thesis Committee Member
      Amy Brown, Compacted solid additive blends have attracted the interest of the polymers industry due to their ability to improve processability. However, limited research has been performed to analyze the thermal properties that these additives have during pelletization.This research studies the reaction behavior of erucamide and silica, when in a pure and mixed form, with each other when thermal conductivity and frictional heating experiments are conducted. During the thermal conductivity study, it was found that pure erucamide had a thermal conductivity of 0.37 W/mK. The thermal conductivity of pure silica could not be found since silica will not compact to itself. Therefore, the thermal conductivity was extrapolated and found to be 0.09 W/mK. With the higher thermal conductivity belonging to erucamide, the heat transference that occurs during pelletization is through the use of erucamide. During the frictional studies, it was found that erucamide had a lower coefficient of friction compared to silica. The samples used were not pure, meaning a presence of both silica and erucamide were present for all experiments. The value obtained for the sample with a 75wt% of erucamide was 0.26. The value obtained for the sample with 75wt% of silica was 0.53. The surface and cross-section morphology and composition of the samples was examined by Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy. Through this a softened layer was seen that provided evidence of an outer protective layer that forms during the pelletization process. Further analysis into this formed softened layer for varying compositions provided critical temperatures that need to be reached during processing.
      Brown_uta_2502M_12486.pdf (5.174Mb) (Material Science and Engineer)
      Compaction Physics Of Solid Additive Blends : A Thermal Properties Study
    • Mar 2014
      Dissertation Committee Member
      Sanchali Deb, Gastroparesis is a common disorder caused to patients suffering from diabetes, cancer and Parkinson's disease. Gastric electrical stimulation (GES) has attracted significant attention in the treatment for Gastroparesis. GES inflicts electrical pulses to the stomach tissues to help regain normal motility and hence reduces Gastroparesis symptoms like vomiting, nausea, abdominal bloating etc. Conventional gastric stimulator needs a long surgery to be implanted and it is a big pacemaker like device that runs by a non-rechargeable battery. It has to be replaced once the battery gets exhausted. Hence another round of surgery is done when these devices are needed to be replaced and re-implanted. This takes the toll over the patients both physically and financially. Most of the times the insurance companies deny to bear the cost and hence the patient cannot afford a treatment. In this work, two miniaturized wireless gastric stimulators for delivering GES as long-term implants have been designed and demonstrated. These devices are designed as such that they can be implanted through endoscopic implantation and the patients do not need to undergo any surgery at all for the implantation. Wireless telemetry for both devices is based on inductive coupling at a carrier frequency of 1.3 MHz from an external transmitter which delivers power. One design embodies a rechargeable battery with a circuitry to recharge the battery. The magnetic coupling is used to turn the device ON and OFF. The second device is completely batteryless with a circuitry to harvest the radio-frequency energy in real time. Both the circuits were made on printed circuit boards which consisted of microcontroller and many other discrete components. These were coated with biocompatible polymer to protect the implant circuitry from the gastric fluids or any other medium that is present in the stomach. The transmitter consists of a class-E amplifier model and resonance circuitry. An optimization procedure was investigated for achieving the maximum wireless energy transfer for the radio-frequency inductive coupling. The devices have been tested on an acute pig model and Electrogastrogram (EGG) signals of the stomach were recorded. The stomach motility was monitored based on the frequency and amplitude of the myoelectrical pulses and also their consistency. The output voltage was also noted to analyze the power delivery to the tissues. These experiments revealed favorable and significant impacts on the gastric electrical activity.Once the devices were tested surgically, a series of animal experiments were performed on porcine model to demonstrate the feasibility of the device implantation through endoscopy. Several endoscopy procedures were investigated successfully to provide many possibilities of implantation for the doctors. Endoscopic implantations are outpatient procedures and thus by implanting it endoscopically any surgery need can be avoided.
      Deb_uta_2502D_11119.pdf (20.03Mb) (Electrical Engineering)
      Miniature Wireless Gastrostimulator
    • Mar 2014
      Dissertation Committee Member
      Wen-Ding Huang, pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages. Glass electrodes are easily affected by alkaline or HF solution, they require a high input impedance pH meter, they often exhibit a sluggish response. In some specific applications, it is also difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to the difficulty of size miniaturization, planarization and polymerization based on current manufacturing technologies. In this work, we have demonstrated a novel flexible pH sensor based on low-cost sol-gel fabrication process of iridium oxide (IrOx) sensing film (IROF). A pair of flexible miniature IrOx/AgCl electrode generated the action potential from the solution by electrochemical mechanism to obtain the pH level of the reagent. The fabrication process including sol-gel, thermal oxidation, and the electro-plating process of the silver chloride (AgCl) reference electrode were reported in the work. The IrOx film was verified and characterized using electron dispersive analysis (EDAX), scanning electron microscope (SEM), and x-ray diffraction (XRD).
      Huang_uta_2502D_10655.pdf (4.081Mb) (Electrical Engineering)
      A pH Sensor Based On A Flexible Substrate
    • July 2013
      Master's Thesis Committee Member
      Venkatesh Majji, Diamond-like carbon thin films are been used in wide range of applications due to their attractive tribological properties. Metal-doped DLC films have significant properties which make them compatible to use in larger variety of applications. The present study examines the dispersion and their effect on various tribological properties when Ag is incorporated into the DLC thin films. These Ag-DLC nanocomposite films were synthesized by a hybrid CVD and magnetron sputtering process in a discharge composed of CH4, and Ar atmosphere. These DLC and Ag-DLC films were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy. Tribological tests were carried out to measure the frictional and wear behavior of the Ag-DLC films as a function of Ag content. The TEM cross sectional studies revealed that Ag is present as Ag nanoparticles that were distributed uniformly throughout an amorphous DLC matrix. XPS analysis confirmed that Ag in the nanoparticles was present in the metallic form. Increasing the Ag content in the film, reduced its sp3 content. The incorporation of these nanoparticles causes a reduction in hardness in Ag-DLC when compared with pure DLC films. Microhardness of DLC films exhibits values up to a maximum of 16 GPa and gradually decreases with increasing in Ag content. FTIR and Raman studies confirmed that the films contain a significant amount of hydrogen, and with an increase in the Ag content in the DLC film results in an increase in sp2 carbon content. Finally, the friction behavior of the Ag-DLC films showed a comparable performance with that of DLC films with a coefficient of friction as low as 0.1. The DLC films exhibited a lower wear rate of 5.51x10-8 mm3/Nm than Ag-DLC films. The wear rate in the Ag-DLC films gradually increased with increasing Ag content but it remained at low levels (i.e., up to 1.7x10-7 mm3/Nm). This is consistent with the higher sp2 content of the Ag-DLC films.
      Majji_uta_2502M_11925.pdf (2.091Mb) (Material Science and Engineer)
      Synthesis Of Silver-diamond Like Carbon Thin Films By Magnetron Sputtering
    • Dec 2012
      Dissertation Committee Member
      Uday Shankar Tata, Cell migration is a central process in the development and maintenance of tissues. Any deviation in the process can have serious consequences, such as atherosclerosis and cancer metastasis. During cancer metastasis, chemokines produced at secondary sites form chemical gradients and attract the cancer cells from primary sites. One of the primary limitations for the study of cancer cell migration has been the lack of a suitable cost-effective assay for cell migration with easy translatability to clinical situations. To address these issues, a microfluidic device was designed for assaying of cancer cell migration towards different chemoattractants.
      Tata_uta_2502D_11893.pdf (39.75Mb) (Electrical Engineering)
      Micromachined Devices For In Vitro Biomedical Applications
    • Apr 2012
      Dissertation Committee Member
      Lun-Chen Hsu, A batteryless, wireless, sensing system, suitable for biomedical applications, was studied in this dissertation. The sensing system contains a reader and a transponder and the working principle is based on passive RFID systems. The transponder harvests the RF energy from the reader to power up the frequency generator circuit which is modulated by sensor signals. Sensor signals are encoded into frequency shifts to provide the immunity to motion artifacts and the robust performances of sensing system are demonstrated. The sensing platform can also be used for multiple sensor integration for different medical applications.
      Hsu_uta_2502D_10458.pdf (11.68Mb) (Electrical Engineering)
      Physiological Telemetric Sensing Systems For Medical Applications
    • Oct 2011
      Dissertation Committee Member
      Aydin Farajidavar, Chronic pain is an important public health issue. Several approaches have been implemented for management of chronic pain, including surgical implantation of neurostimulators. Neurostimulators have been used in clinics for spinal cord implantation and they have been suitable for relieving certain types of pains, such as neuropathic pain in leg or arm, complex regional pain, and refractory angina. The stimulation at spinal cord has little relieving effects on syndromes such as facial pain, cluster headache, phantom limb pain, and post stroke pain. For treating such syndromes, electrical stimulation of deep brain structures such as thalamic nuclei (e.g. ventroposterolateral (VPL) or ventroposteromedial (VPM)), periaqueductal gray (PAG), periventricular gray (PVG), anterior cingulate cortex (ACC) and other regions near the central gray has been clinically suggested.

      Wireless Closed-loop Feedback Systems For Automatic Detection And Suppression Of Nociceptive Signals
    • May 2011
      Sandeep Manandhar, Tissue engineering merges the disciplines of study like cell biology, materials science, engineering and surgery to enable growth of new living tissues on scaffolding constructed from implanted polymeric materials.
      University of North Texas: UNT Digital Library

      (Material Science and Engineer)
      External Dissertation Committee Member, University of North Texas
      Bioresorbable Polymer Blend Scaffold for Tissue Engineering
    • Apr 2008
      Dissertation Committee Member
      Thermpon Ativanichayaphong, The deployment of medical electronics in healthcare plays a significant role to overcome many problems in disease treatment and diagnosis. For advanced applications, wireless solutions are preferred. The wireless technologies offer a new dimension of therapy or diagnosis, when wires are often bulky, unsafe, uncomfortable or even impossible to be deployed in some circumstances. The wireless communication devices can be categorized into two groups, active and passive, depending on the power sources operating electronics. The active devices draw powers from a battery, while the others harvest powers from external or internal sources. In this work, two medical applications are studied for pain management and gastroesophageal reflux diagnosis using active and passive wireless approaches, respectively. The pain management systems are based on neurostimulation and neurorecording principles. The system requires batteries in implants for wireless communication. The neurostimulation can significantly improve pain relief when used on carefully selected chronic pain patients. An integrated recording and stimulating system has been designed, developed and used in animal experiments. The system consists of miniature components to record neuronal signals from the spinal cord and to activate the stimulation in the brain wirelessly. The system is equipped with a feedback function and decision making capability to automatically activate the stimulation from the recorded signals. A wearable prototype was tested in anesthetized rats. The results show that, when suitable stimulation parameters are used, the brain stimulation inhibits neural responses which may cause pain. For gastroesophageal reflux diagnosis, a new method of wirelessly detecting reflux in esophagus was proposed. Based on passive telemetry using inductive links, impedance of the refluxates can be determined remotely. The impedance variation can be determined from either amplitude or frequency changes of the detected signals. Planar coils integrated with electrodes on flexible substrates have been fabricated for amplitude detection. A circuitry connected with the sensing electrodes has been built for frequency detection. The devices are characterized in acid and non-acid solutions including the experiments in animals. Both techniques were used in implantable sensors without a battery to distinguish air, water and acid reflux wirelessly with a reader. The design methodology can also be applied to other sensors to monitor physiological conditions in human body.
      umi-uta-1884.pdf (4.203Mb)

      (Electrical Engineering)
      Wireless Devices For Medical Applications