Resume

• 2009

  PhD

  PhD Dissertation Title: Mechanical Behavior and Environmental Stability of GLAD-based Copper Nanospring Films for Nanothermal Interfaces\nAdvisor: Prof. Ioannis Chasiotis\nGPA: 3.86/4.00

  Aerospace Engineering (Materials and Structures)

  Philosophical Society of Turkey

  Society for Experimental Mechanics (SEM)

  Society for Industrial and Applied Mathematics

  Society for the Advancement of Material and Process Engineering

  American Society for Composites

  Materials Research Society

  University of Illinois at Urbana-Champaign

  All research safety and experimental facility supervision certificates of the Texas A&M System

  TAMU College Station

• 2007

  M.S.

  M.Sc. Thesis Title: Mechanical and Interfacial Properties of Carbon Nanofibers for Polymer Nanocomposites\nGPA: 4.00/4.00

  Mechanical Engineering

  GEO

  Federation of Teachers Illinois Branch

  Landesverwaltung der Amischen Gemeinde in den Vereinigten Staaten für landwirtschaftliche Entwicklung

  University of Illinois at Urbana-Champaign

• 2002

  BS

  B.Sc. Thesis Title: Improvement of Process Yield and Octane Rating for Biodiesel Synthesis by Mechanical and Acoustic Means \nGPA: 3.79/4.00

  Mechanical Engineering

  Founding member of Solar Car & SAE Mini Baja Teams

  Member of the Environmental Safeguarding Club

  Founding member of the Eastern Thrace Biodiesel Initiative (биодизел инициатива по Тракия)

  Bosphorus University

• Students demonstrate 3D printing technology's potential value for society on the 25th anniversary of ADA | 22 | 07 | 2015 | News & Events | College of Engineering

  A team of students from the Department of Mechanical Engineering at Texas A&M University recently showcased its 3D printing skills by printing braille labels on prescription bottles. The team is led by Dr. Tanil Ozkan

  who is a visiting assistant professor in the department.

  Students demonstrate 3D printing technology's potential value for society on the 25th anniversary of ADA | 22 | 07 | 2015 | News & Events | College of Engineering

  Texas A&M's 3D Braille Printer Can Print on Any Curved or Flat Plastic Surface

  As technology improves

  so do the lives of those individuals living with disabilities all around the world. 3D printing has become one of those technologies aiding in creating custom devices

  prostheses

  and more for individuals who previously would have been left with fewer reliable options.

  Texas A&M's 3D Braille Printer Can Print on Any Curved or Flat Plastic Surface

  Nanoparticle/Microwave Interactions

  Simulations

  Mathematical Modeling

  Nanofabrication

  Finite Element Analysis

  Characterization

  Nanocomposites

  Composites

  MEMS

  Process Engineering

  Materials Development

  CVD

  Functionally Graded Materials

  Solid Mechanics

  Fracture Mechanics

  Structures

  Nanotechnology

  AFM

  Experimental Research

  Nanomaterials

  Interfacial strength and fracture energy of individual carbon nanofibers in epoxy matrix as a function of surface conditions

  Ioannis Chasiotis

  The interfacial shear strength (IFSS) and fracture energy of individual carbon nanofibers embedded in epoxy were obtained for different surface conditions and treatments by novel

  MEMS-based

  nanoscale fiber pull-out experiments. As-grown vapor grown carbon nanofibers (VGCNFs) with turbostratic surface and 5 nm peak-to-valley surface roughness exhibited high IFSS and interfacial fracture energy

  averaging 106 ± 29 MPa and 1.9 ± 0.9 J/m^2

  respectively. Subsequent high temperature heat treatment and graphitization resulted in drastically reduced IFSS of 66 ± 10 MPa and interfacial fracture energy of 0.65 ± 0.14 J/m^2. The smaller IFSS values and the reduced standard deviation were due to significant reduction of the fiber surface roughness to 1–2 nm

  as well as a decrease in surface defect density during conversion of turbostratic and amorphous carbon to highly ordered graphitic carbon. For both grades of VGCNFs failure was adhesive with clear nanofiber surfaces after debonding. Oxidative functionalization of high temperature heat-treated VGCNFs resulted in much higher IFSS of 189 ± 15 MPa and interfacial fracture energy of 3.3 ± 1.0 J/m^2. The debond surfaces of functionalized nanofibers had signs of matrix residue and/or shearing of the outer graphitic layer of the VGCNFs

  namely the failure mode was a combination of cohesive matrix and/or cohesive fiber failure which contributed to the high IFSS. For all three grades of VGCNFs the IFSS was independent of fiber length and diameter. The findings of this experimental study emphasized the critical role of nanofiber surface morphology and chemistry in determining the shear strength and fracture energy of nanofiber interfaces

  and shed light to prior composite-level strength and fracture toughness measurements.

  Interfacial strength and fracture energy of individual carbon nanofibers in epoxy matrix as a function of surface conditions

  In this study

  the aim is to configure the cutting operations made use of during the production of Hydroxilapatite (HAp) - a highly biocompatible ceramic used in orthopedics and dentistry as an implant and implant coating material - from cow femoral bone in such a way that maximum surface area is achieved. First

  the cutting patterns which would yield the highest surface area when applied to a cow femur of known geometric properties have been investigated using a computer code prepared with the technical computing program

  MATLAB 6.5. The obtained results have been compared with the results of cutting operations applied on a realistic 3-D bone model prepared using CATIA v5 modeling software.

  Theoretical Maximization of Cow Femur Cut Surface Area for Hydroxilapatite Production

  Ioannis Chasiotis

  The complex effects of near ambient temperature exposure

  i.e. 20-150 ºC

  on the oxidation and the mechanical properties of thermal solution grown faceted Cu nanowires were investigated. The mechanical behaviour was quantified with experiments on individual Cu nanowires using a MEMS-based method for nanoscale mechanical property studies. The elastic modulus of pristine Cu nanowires with diameters 300-550 nm was 117±1.2 GPa which agreed very well with polycrystalline bulk Cu

  while the ultimate tensile strength was more than three times higher than bulk Cu

  averaging 683±55 MPa. Annealing at only 50˚C resulted in marked strengthening by almost 100% while the elastic modulus remained unchanged. Heat treatment in ambient air distinguished three different regimes of oxidation

  namely the (a) formation of a thin passivation oxide at temperatures up to 50˚C

  (b) formation of thermal oxide obeying an Arrhenius type process for Cu+ migration at temperatures higher than 70˚C

  which was accelerated by grain boundary diffusion resulting in activation energies of 0.17-0.23 eV

  and (c) complete oxidation following the Kirkendall effect at temperatures higher than 150 ˚C and for prolonged exposure times

  which did not obey an Arrhenius law. Notably

  the formation of a weaker and more compliant thermal Cu2O did not compromise the effective strength and elastic modulus of oxidized Cu nanowires: experiments in Ar at temperatures higher than 70ºC showed mechanical strengthening by ~50% and ultimate stiffening to ~190 GPa

  which is near the upper limit for the elastic modulus of single crystal Cu in the <111> direction.

  Mechanical strengthening

  stiffening

  and oxidation behaviour of pentatwinned Cu nanowires at near ambient temperatures

  John R. Abelson

  Thin films of HfBxCy are deposited in a cold wall CVD apparatus using Hf(BH4)4 precursor and\n3

  3-Dimethyl-1-butene

  (CH3)3CCH=CH2

  as a controllable source of carbon

  at substrate\ntemperatures of 250-600°C. As-deposited films grown at 250°C are highly conformal in trenches\nwith aspect ratios of at least 30:1

  exhibit dense microstructure

  and appear amorphous in X-ray\ndiffraction. Increasing the carbon content from 5 to 21 at. % decreases the hardness from 21 to 9\nGPa and the elastic modulus from 207 to 114 GPa. Films grown at 600°C with carbon contents\nof 28 and 35 at. % exhibit enhanced hardness of 25 and 23 GPa

  and elastic modulus of 211 and\n202 GPa

  respectively. Annealing the 300°C grown films at 700°C affords a nanocrystalline\nstructure with improved mechanical properties: the H/E and H3/E2 ratios range from 0.08-0.11\nand 0.15-0.40

  respectively

  which are predicted to exhibit improved friction and wear\nperformance in tribological applications.

  Conformal growth of low friction HfBxCy hard coatings

  Potentials of Augmented Reality (AR) and Virtual Reality (VR) for Mechanical Engineering Education at the Age of Personal 3D Printers

  Arun Srinivasa

  Troy Mitchell

  All Fortune 500 companies dealing with some form of product design

  development and manufacturing processes are implementing new strategies to adapt to the rapidly changing manufacturing landscape after the digital revolution in the last two decades of the 20th century. For the first time since the industrial revolution

  engineers are observing a trend which is challenging all mass production based manufacturing paradigms. 3D printing and additive manufacturing sit at the very heart of this transition. The 2015 Higher Education Edition of the NMC Horizon Report has identified 3D printing as one of three technologies (the other two are big data/cloud computing and wearable tech) expected to enter mainstream use in the midterm horizon of three to five years. “One of the most significant aspects of 3D printing for education

  ” the report notes

  “is that it enables more authentic exploration of objects that may not be readily available to universities.” Based on the AR/VR systems development experience in the 3D Printing Studio and MEEN 361 Materials and Manufacturing in Design Laboratory of the Department of Mechanical Engineering at Texas A&M University

  classes discuss opportunities and challenges presented by these emerging technologies for mechanical engineering education. From the holistic pedagogic perspective of integrating advanced technology driven learning objectives into existing curriculum of mid-years students

  the Department of Mechanical Engineering at Texas A&M University is able to enhance the learning experience and innovation potential of students

  making them more competitive in the job market and supplying them with indispensable skills for their professional careers after graduation.

  Potentials of Augmented Reality (AR) and Virtual Reality (VR) for Mechanical Engineering Education at the Age of Personal 3D Printers

  Ioannis Chasiotis

  Mohammad Naraghi

  Individual as-fabricated

  high temperature heat-treated and graphitized/surface oxidized vapor grown carbon nanofibers (VGCNFs)

  with average diameter of 150 nm were tested for their elastic modulus and their tensile strength by a MEMS-based mechanical testing platform. The elastic modulus increased from 180 GPa for as-fabricated

  to 245 GPa for high temperature heat-treated nanofibers. The nominal fiber strengths followed Weibull distributions with characteristic strengths between 2.74 and 3.34 GPa

  which correlated well with the expected effects of heat treatment and oxidative post-processing. As-fabricated VGCNFs had small Weibull modulus indicating a broad flaw population

  which was condensed upon heat treatment. For all VGCNF grades

  the nanofiber fracture surface included the stacked truncated cup structure of the oblique graphene layers comprising its backbone and cleavage of the outer turbostratic or thermally graphitized layer.

  Mechanical Properties of Vapor Grown Carbon Nanofibers

  Ioannis Chasiotis

  A novel experimental method for the interfacial mechanics of nanofibers and nanotubes was developed. The debond force was determined by MEMS devices whose motion was precisely measured from optical images by digital image correlation. Essential elements of this method are the submicron control of nanofiber/nanotube embedded length in a thermoplastic or thermosetting polymer and the application of well controlled pull-out force until terminal debonding. The cross-head displacement resolution is at least 20 nm whereas a force resolution of the order of nanonewtons is maintained. A traceable force calibration technique was integrated to calibrate the MEMS force sensors. The method allows for nanofiber pull-out experiments at time scales varying from microseconds to hours and at hot/cold temperatures. Experiments have been conducted for the first time with ø150-350 nm carbon nanofibers embedded in EPON epoxy to demonstrate the applicability of the proposed method. The present experiments are the first of their kind both in terms of experimental fidelity and data coherence compared to prior experimental attempts

  pointing out to the robustness of this new method.

  Standardization of nanoscale interfacial experiments using MEMS

  Kathleen A. Walsh

  Density modulated tungsten (W) thin film samples whose nanoscale porosity contents ranged\nfrom 7% to 40% by volume were grown on Si substrates through magnetron sputter deposition.\nProcess parameters for the film growth were selected according to the structure zone model\n(SZM)

  which resulted in film thicknesses between 105 nm and 520 nm. Nanomechanical\nproperties of W films were investigated by means of instrumented nanoindentation. Reduced\nchi-square analysis was carried out to assess four different models formulated through differential effective medium approach (DEMA). The model that factored in both the crowding effect and the maximum random packing of pores

  successfully captured the experimental trends present in the reduced modulus data as a function of porosity. Attempts to breach the auxetic barrier by increasing the porosity content beyond the level predicted by the model with the highest fidelity resulted in either large-scale pulverization during deposition or spontaneous conversion of the deposited film into WO3 under ambient conditions. Porosity corrected yield strength calculations revealed that it is indeed possible to define a porosity threshold beyond which the compressive yield strength of density modulated metallic thin films would drop abruptly due to aggravated geometric slenderness effects in agreement with earlier hypotheses.

  Density modulated nanoporous tungsten thin films and their nanomechanical properties

  Silicon (Si) electrodes possess a theoretical specific capacity nearly ten times that of current graphite electrodes used in lithium ion batteries. However

  lithiation and delithiation induce large volume changes within the Si

  resulting in cracking and eventual capacity loss with cycling. Recent experimental evidence indicates that the presence of nanoporosity may mitigate capacity fade. By implementing a scalable differential effective medium approach

  we elucidate the effects of nanoporosity upon the mechanical properties of fully-lithiated amorpohous Si anode films. Our analytical findings suggest that increased pore volume fraction significantly alters the mechanical properties of nanofilms and enhances anode survivability. Meanwhile

  the auxetic limit imposes an upper bound on porosity specific fracture toughening. Overall

  the results of this paper provide design guidelines for multilayered nanoporous Si thin films with increased capacity retention.

  Mechanical Properties of Nanoporous Si Anodes using a Continuum Mechanical Model

  Maarten P. de Boer

  Sidhart S. Hazra

  Ioannis Chasiotis

  Mohammad Naraghi (1st author)

  A new nanoscale tension testing platform with on-chip actuation and the unique capability for nanoscale mechanical characterization of highly deformable and strong nanostructures is presented. The specimen force and extension measurements are based on optical imaging

  supported by digital image correlation

  which allows the resolution of 20 nm specimen extensions and force measurements better than 30 nN

  without the use of high-resolution electron microscopy. The breakthrough of this nanomechanical testing platform is the ability to study the mechanical behavior of nanostructures subjected to a wide range of forces (30 nN–300 μN) and displacements (20 nm–100 μm)

  which are beyond the limits of typical surface micromachined MEMS with on-chip actuators

  such as comb-drives and thermal actuators. The utility of this device in experimental nanomechanics is demonstrated by investigating the mechanical behavior of electrospun 1-D polyacrylonitrile nanostructures with diameters of 200–700 nm subjected to strains as high as 200%. The mechanical property measurements were compared to and agreed well with off-chip measurements by an independent testing method

  which validates the capability of this on-chip testing platform to characterize strong and highly ductile nanomaterials.

  MEMS platform for on-chip nanomechanical experiments with strong and highly ductile nanofibers

  Driven by both the implications of the recent disaster in Fukushima as well as the coming maturity of fusion reactors in energy infrastructure

  the nuclear industry is experiencing a renaissance not only in reactor design and fuel systems but also in safety. However

  the combination of high temperature

  high pressure

  and radiation intensityof a reactor core poses a challenge to material selection for engineers

  particularly related to nuclear cladding. Creep and cracking pose a threat to the cladding’s functional integrity. As a result

  high fracture toughness

  low thermal expansion coefficient

  and wear resistance become crucial metrics for the design and selection of nuclear cladding material for control rods. In response to these metrics

  boron carbide (B4C) and Ag–In–Cd alloy have emerged as promising candidates for usage in control rod claddings. However

  nanoporosity can impart significant mechanical advantages including higher fracture toughness

  increased defect annihilation

  and suppressed irradiation swelling. Density-modulated tungsten thin films with tunable nanoporosity can be manufactured through sputter coating. Consequently

  density-modulated tungsten thin films have the potential to contribute to next-generation control rod cladding. Thus

  the objective of this paper is to investigate the suitability of density-modulated tungsten thin films for nuclear control rod cladding through the analytical hierarchy process. Overall

  conservative analytical hierarchy process analysis indicates that nanoporous tungsten is competitive with B4C for control rod cladding. As a result

  our study may motivate current and future control rod cladding material development efforts focusing specifically on hybrid density-modulated tungsten thin film and B4C architectures for next-generation nuclear power plants.

  Nanoporous Tungsten for Improved Mechanical Performance and Safety in Nuclear Control Rod Cladding

  Three grades of VGCNFs

  namely as-fabricated

  high temperature heat treated

  and graphitized/surface oxidized

  with average diameters of 150 nm were tested individually for their tensile strength by a MEMS mechanical testing platform. Their nominal tensile strengths followed Weibull distributions with characteristic strength values between 2.74- 3.34 GPa

  which correlated well with the expected effects of heat treatment and oxidative post-processing. These values are the first measurements reported for VGCNFs and are more than 50% smaller than the generally accepted values for the tensile strength of this class of nanofibers. The as-fabricated nanofibers had the smallest Weibull modulus indicating a wide flaw population that was reduced significantly upon heat treatment. Under uniaxial tension

  cleavage of the outer turbostratic layer occurred first

  followed by relative slip of the internal oblique graphene layers. The change in the mechanical strength (Weibull strength)

  and its scatter (Weibull moduli)

  with heat treatment correlated well with the fiber structure evidence in Transmission Electron Microscopy (TEM) images

  which showed graphitization of the outer turbostratic layer and the formation of a new interface with the inner

  originally graphitic

  layer that was characterized by structural discontinuities that reduced the total load bearing capacity of the nanofibers. In this work

  the strength of the carbon nanofiber-polymer matrix interfaces was also quantified for the frrst time by means of novel nanoscale fiber pull-out experiments. The interfacial shear strength averaged 55 MPa revealing that the adhesion and bonding of the heat-treated

  non-functionalized carbon nanofibers is quite better than that of non-functionalized carbon fibers (15-28 MPa) and as good as that of functionalized carbon fibers ( 40-65 MPa)

  which underscores that extrapolations of macroscale interfacial measurements to the nanoscale are not appropriate.

  Ioannis Chasiotis

  Tanil

  Ozkan

  Texas A&M University

  Dover Precision Components

  Ford Motor Company

  The Nanomechanics and Materials Research Laboratory (NMRL) of UIUC

  DuPont

  University of Illinois at Urbana-Champaign LINC

  Texas A&M University Department of Mechanical Engineering & NCTM

  Houston

  Texas Area

  At the Engineering Polymers Innovation Center (EPIC) of Dover Precision Components in Pearland

  TX

  we are pushing the limits of high performance engineering polymers and their nanocomposites to ensure optimum efficiency

  reliability

  productivity and environmental stewardship in even the most challenging operating environments across the oil & gas

  power generation

  marine

  industrial

  chemical and general processing markets. Our team led by Dr. Burak Bekisli is committed to safety

  quality

  sustainability and continuous improvement in all that we do.

  Materials Engineer and Additive Manufacturing Specialist

  Dover Precision Components

  Intern at the Engineering Polymers Division of \nDuPont de Nemours Intl. S.A. European Technical Centre \nRepublic and Canton of Geneva / Switzerland

  DuPont

  Research Assistant

  Title of the doctor philosophiae (Ph.D.) dissertation: MECHANICAL BEHAVIOR AND ENVIRONMENTAL STABILITY OF GLAD-BASED COPPER NANOSPRING FILMS FOR NANOTHERMAL INTERFACES\nhttps://www.ideals.illinois.edu/handle/2142/49795\n\nTitle of the magister scientiae (M.Sc.) thesis: MECHANICAL AND INTERFACIAL PROPERTIES OF VAPOR GROWN CARBON NANOFIBERS FOR POLYMER NANOCOMPOSITES\nhttps://www.ideals.illinois.edu/handle/2142/47634

  The Nanomechanics and Materials Research Laboratory (NMRL) of UIUC

  University of Illinois at Urbana-Champaign LINC

  UIUC College of Engineering

  http://linc.illinois.edu/electric-vehicle-initiative

  Electric Vehicle Initiative Project Manager

  Intern at the Production Maintenance Division of Ford/Otosan Turkey.\nGolcuk Commercial Vehicle Manufacturing Plant\nKocaeli - Republic of Turkey

  Ford Motor Company

  Texas A&M University Department of Mechanical Engineering & NCTM

  Bryan/College Station

  Texas Area

  Teaching:\nMEEN 360 Materials and Manufacturing in Design\nMEEN 361 Materials and Manufacturing Laboratory (Instructor of Record)\nMEEN 402 Senior Design \nMEEN 404 Engineering Laboratory\nMEEN 467 Mechanical Behavior of Engineering Materials\nMEEN 475 Materials Selection in Design\nMEEN 485 Directed Studies: Carbon Nanofiber Functionalized Electroactive Polymer Composites \nMEEN 625 Mechanical Behavior of Advanced Materials\n\n\nTechnology Research:\nCollaboration with Polycarpou Research Group (Nanotribology and Functional Thin Film Technology)\nResearcher and System Developer at the MEEN 3D Printing Studio \nMember of the Texas A&M Energy Research Society\n\nDidactic Research:\nImplementation of Virtual Reality in Materials Testing Curriculum of Mechanical Engineering\nExperiential Learning Enhancement in Engineering Labs through Virtual Reality\nVirtual Reality as a Learning Tool for Decision Making in Materials Selection

  Instructional Assistant Professor

  Department of Mechanical Engineering

  3D Printing Materials Innovation Lab

  Teaching:\nMEEN 222 Introductory Materials Science\nMEEN 361 Materials and Manufacturing Laboratory (Instructor of Record)\nMEEN 489/689 Entrepreneurship Related to Nanomaterials for Energy Applications (Guest Lecturer for Technical Lectures)\nMEEN 489 Custom Manufacturing (with Dr. Bruce Tai

  I focus on Additive Manufacturing and Direct Digital Manufacturing

  i.e. DDM in this class)\n\nResearch:\nMember of the Polycarpou Research Group\nResearcher and System Developer at the 3D Printing Materials Innovation Laboratory (affiliated with the 3D Printing Studio of the Mechanical Engineering Department)\nMember of the Texas A&M Energy Research Society

  Visiting Assistant Professor

  Texas A&M University

  Polycarpou Research Group

  ENG\nFrom the general mechanics point of view

  the true beauty and brilliancy of the existing order within the physical universe is the following: Although the holonic architecture keeps the fundamental laws for the entire spatio-temporal spectrum more or less the same

  it also provides a certain degree of autonomy within each individual scale without sacrificing the overall compatibility such that formation of a fragile system of absolute hierarchy is wisely avoided. Inspired by this very principle

  here at the Polycarpou Research Group of Texas A&M University

  we employ state of the art experimental techniques and pure human reasoning to unravel mechanical mysteries of novel nanostructured materials and thus identify key engineering concepts of the nanoscale with particular emphasis on multifunctional

  tribological and 3D printing oriented applications. \n\nGER\nIn der Natur ist alles nach Maß

  Zahl und Verhältniswert geordnet. Durch unsere Experimente in der Polycarpou Forschungsgruppe versuchen wir einige grundlegende Prinzipien dieser Ordnung sowie unter besonderen Bedingungen auftretende mechanische und tribologische Eigenschaften für neue Materialien und multifunktionale Bauelemente von verschiedenen Spitzentechnologien auf der Nanometer-Skala zu erklären.

  Postdoctoral Research Associate

  Texas A&M University

  American Society for Engineering Education

  Turkish

  Arabic

  German

  English

  Top 5 Entry in the Consumer Products Category of the Create the Future 2015 Design Contest with the '3D Printer to Aid Visually Impaired Consumers in Their Daily Life'

  The Certificate of Achievement presented to Tanil Ozkan on behalf of Texas A&M 3D Braille Printeers Team (Yasushi Mizuno

  Eduardo Vasquez and Bryan Conlee) recognizing the submission '3D Printer to Aid Visually Impaired Consumers in Their Daily Life' as a Top 100 Entry in the general contest and as a Top 5 Entry in the consumer products category.

  Joseph T. Pramberger

  President

  Tech Briefs Media Group