September 2017 - Msepostdoc-list

Seminar Notice for Megan Forshey's Preliminary Exam, Tuesday, October 3, at 1:30 p.m., in ARMS 1109. "Real-Time Spectral Birefringence Technique to Determine Polymer Morphology
by Son, Rosemary E 02 Oct '17

02 Oct '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Real-time Spectral Birefringence Technique to Determine Polymer Morphology" By Megan Froshey Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Mukerrem Cakmak ABSTRACT It is difficult to predict complicated viscoelastic polymer responses when subjected to mechanical deformation. One way to measure microstructural changes during these processes is to pass white light through the sample and measure its retardation over time. The difference in chain orientation in axial directions affects how light interacts with the polymer sample, and converting this retardation to birefringence provides a way to quantify changes in polymer chain orientation. Historically, systems used to measure birefringence of polymers were very simple and led to various errors, such as human interpretation of results. Furthermore, they were not able to provide precise, quantitative results and never before were able to track polymer properties in real time. This presentation discusses the development of real-time spectral birefringence technique to quantify microstructure of polymers- a novel way to quickly and accurately measure changes in polymer structure while undergoing complicated processing steps, simulating those in industry. This technique can be applied to any situation in which polymers are subjected to thermal or mechanical stresses - such as film orientation, annealing, and drying - and has the goal of providing constitutive relationships between mechanical and optical properties of polymers to allow for prediction and control of polymer morphology. Important applications include biaxial film orientation, used in capacitors and food packaging, as well as novel technologies such as photovoltaics and wearable health sensors. Date: Tuesday, October 3, 2017 Time: 1:30 P.M. Place: ARMS 1109

1 1

Reminder for Hyeyoung Son's Preliminary Exam Seminar, Oct. 2, at 8:30 a.m., in ARMS 1021, "Thin Polymeric Film Adhesion Through the Transition Between Surface Wrinkling and Delamination"
by Son, Rosemary E 29 Sep '17

29 Sep '17

Reminder to attend Hyeyoung Son's Preliminary Exam Seminar: MATERIALS ENGINEERING SEMINAR "Thin Polymeric Film Adhesion Through the Transition Between Surface Wrinkling and Delamination" By Hyeyoung Son Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Chelsea S. Davis ABSTRACT Thin polymeric film play an important role in many applications, including microelectronics, flexible displays, and protective film for products. Poor adhesion between a thin film and the underlying substrate can cause defects such as corrosion and delamination during processing and use. On the other hands, strong adhesion can result in sticky residue on the products. Therefore, controlling adhesion of thin film has been important in those applications. However, the adhesion of polymer thin films is hard to measure due to their brittleness, greatly complicating sample preparation and handling. Here, a method for measuring the adhesion of polymeric thin films to a soft elastomeric substrate is proposed which exploits the transition from wrinkling to delamination. In prior research, the critical strain for film delamination from a wrinkled surface has been well described mathematically and is affected by the thickness of the thin film, the critical strain energy release rate and the plane strain modulus of the thin film and substrate. Based on this critical delamination strain relationship, the critical strain energy release rate (a metric of the interfacial adhesion) is verified through the use of a well-characterized, model materials system (thin film (polystyrene, PS) and the substrate (poly (dimethyl siloxane), PDMS)) by determining the onset of delamination after wrinkling. In this work, the basic knowledge of the topic is discussed to better understand how the adhesion of polymer is interpreted as a viewpoint of fracture as well as the transition from wrinkling to delamination. Date: Monday, October 2, 2017 Time: 8:30 A.M. Place: ARMS 1021

1 0

Seminar Notice for Yifan Zhang's Preliminary Exam, Thursday, Oct. 5, in ARMS 1021, at 9:30 a.m. "Deformation Twinning in Nanocrystalline Al"
by Son, Rosemary E 27 Sep '17

27 Sep '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Deformation Twinning in Nanocrystalline Al" By Yifan Zhang Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Xinghang Zhang ABSTRACT Deformation twinning is one of the primary deformation mechanisms in numerous metallic materials to accommodate shear strain and plastic deformation. In general, even under extreme deformation conditions, coarse-grained monolithic Al rarely deforms via deformation twinning because of its high stacking fault energy (104-142 mJ/m2). One practical pathway to facilitate deformation twinning is via grain refinement. Experimental studies and molecular dynamic simulations show several unique deformation twinning mechanisms in nanocrystalline (nc) Al with an average grain size of 100 nm or less. Furthermore, physical models have also been established to describe the nucleation and growth process of deformation twins. Date: Thursday, October 5, 2017 Time: 9:30 A.M. Place: ARMS 1021

1 0

FW: [Gradcontacts] Graduate School Professional Development Flyers
by Son, Rosemary E 27 Sep '17

27 Sep '17

Please view these attachments for professional development workshops

1 0

Xingyao Gao's Preliminary Exam Seminar is in ARMS 1028, at 11:30 today, Wednesday, Sept. 27.
by Son, Rosemary E 27 Sep '17

27 Sep '17

School of Materials Engineering Purdue University Neil Armstrong Hall of Engineering 701 West Stadium Ave. Room 2200 West Lafayette, IN 47907 765-494-4105

1 0

Reminder for Jaehun Cho's Preliminary Exam, Thursday, Sept. 28, at 1:30 p.m., in ARMS 1028. "Mechanical Behavior of Yttrin Stabilized Zirconia at Microscale"
by Son, Rosemary E 27 Sep '17

27 Sep '17

Reminder for the following: MATERIALS ENGINEERING SEMINAR "Mechanical Behavior of Yttria Stabilized Zirconia at Microscale" By Jaehun Cho Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Xinghang Zhang ABSTRACT Yttria stabilized zirconia (YSZ) has metastable tetragonal phase at room temperature, which can transform into monoclinic phase with ~ 4% volume expansion under an applied external stress. The phase transformation (martensitic transformation) occurs near a crack tip where the external stress is concentrated and hinders a crack propagation by generating a compressive strain field, thereby enhancing toughness and strength. Recently, it is known that miniaturization of a specimen increases toughness of YSZ by decreasing mismatch stress among grains during martensitic transformation. Furthermore, it turns out that superelasticity and shape memory effect can be tremendously enhanced by scaling down the specimen. In this study, the concept of martensitic transformation and the factors affecting its effectiveness will be explored. Also, the mechanical properties of YSZ at macroscale and microscale will be compared. Lastly, the enhanced superelasticity and shape memory effect will be reported. Date: Thursday, September 28, 2017 Time: 1:30 P.M. Place: ARMS 1028

1 0

Reminder for Xingyao Gao's Preliminary Exam Seminar, Sept. 27, at 11:30 a.m., in ARMS 1028, "Strain Turning and Property Enhancement for Functional Oxides"
by Son, Rosemary E 26 Sep '17

26 Sep '17

Reminder to attending the following: MATERIALS ENGINEERING SEMINAR "Strain Turning and Property Enhancement for Functional Oxides" By Xingyao Gao Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Haiyan Wang ABSTRACT Functional oxides are recognized as potential next-generation electronic materials due to their wide variety of properties, including high-temperature superconductivity, ferroelectricity, colossal magnetoresistance, multiferroism. Functional oxides can be widely used in energy storage, dielectrics, ferroelectrics, superconductors, magnetic, spintronic devices and catalysts. In last two decades, tremendous progress of the thin film growth techniques such as pulsed laser deposition (PLD), magnetron sputtering, spin coating and molecular beam epitaxy (MBE) has been made. With the development of these techniques, precise control of the film growth can be achieved. Strain tuning is one of the most promising methods that can help to enhance the properties of the thin films. According to the origin of the strain, there are three approaches on strain tuning: substrate induced strain, multilayer induced strain and vertically aligned nanocomposite (VAN) induced strain. In this seminar, a brief introduction of each strain tuning approach will be given. Examples will be illustrated on how these strain tuning approaches could enhance the ferroelectricity, multiferroism and magnetoresistance of functional oxides. Date: Wednesday, 27, 2017 Time: 11:30 A.M. Place: ARMS 3115

1 0

Seminar Notice for Hyeyoung Son's Preliminary Exam Seminar, Oct. 2, at 8:30 a.m., in ARMS 1021, "Thin Polymeric Film Adhesion Through the Transition Between Surface Wrinkling and Delamination"
by Son, Rosemary E 25 Sep '17

25 Sep '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Thin Polymeric Film Adhesion Through the Transition Between Surface Wrinkling and Delamination" By Hyeyoung Son Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Chelsea S. Davis ABSTRACT Thin polymeric film play an important role in many applications, including microelectronics, flexible displays, and protective film for products. Poor adhesion between a thin film and the underlying substrate can cause defects such as corrosion and delamination during processing and use. On the other hands, strong adhesion can result in sticky residue on the products. Therefore, controlling adhesion of thin film has been important in those applications. However, the adhesion of polymer thin films is hard to measure due to their brittleness, greatly complicating sample preparation and handling. Here, a method for measuring the adhesion of polymeric thin films to a soft elastomeric substrate is proposed which exploits the transition from wrinkling to delamination. In prior research, the critical strain for film delamination from a wrinkled surface has been well described mathematically and is affected by the thickness of the thin film, the critical strain energy release rate and the plane strain modulus of the thin film and substrate. Based on this critical delamination strain relationship, the critical strain energy release rate (a metric of the interfacial adhesion) is verified through the use of a well-characterized, model materials system (thin film (polystyrene, PS) and the substrate (poly (dimethyl siloxane), PDMS)) by determining the onset of delamination after wrinkling. In this work, the basic knowledge of the topic is discussed to better understand how the adhesion of polymer is interpreted as a viewpoint of fracture as well as the transition from wrinkling to delamination. Date: Monday, October 2, 2017 Time: 8:30 A.M. Place: ARMS 1021

1 0

Reminder for Paul Mather's Preliminary Exam Seminar, Sept. 26, at 11:30 a.m., in HAMP 2107. "Exergy Modeling for the Pyrometallurgical Production of Copper"
by Son, Rosemary E 25 Sep '17

25 Sep '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Energy Modeling for the Pyrometallurgical Production of Copper" By Paul Mather Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Matthew J. M. Krane ABSTRACT 80% of the world's copper is extracted pyrometallurgically. The three high temperature steps important to this process are smelting, converting, and fire-refining. These steps use much energy and are thermodynamically complex. Their literature has focused on modelling the process thermodynamics, kinetics, and furnace operation, with a goal to optimization. Publications linking these latter models to gain system-wide understanding are lacking. There are also no models which analyze entropy generation. As such, the opportunity exists for exploring total system behavior, including the furnace product quantity and quality, and energy, exergy, and feed material requirements, by the creation and linking of transient exergy models of them. Date: Tuesday, September 26, 2017 Time: 11:30 A.M. Place: HAMP 2107

1 0

Reminder for Mitch Rencheck's Preliminary Exam Seminar, Sept 26, at 8:30 a.m., in ARMS 1021 "Buckling Mechanics Metrology of Cellulose Nanocrystal Thin Films"
by Son, Rosemary E 25 Sep '17

25 Sep '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Buckling Mechanics Metrology of Cellulose Nanocrystal Thin Films" By Mitchell L. Rencheck Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Chelsea S. Davis ABSTRACT A major current need for sustainability is in the area of polyolefin plastics (grocery bags, disposable water bottles, milk cartons, etc.) that continue to contaminate our oceans as consumption progresses. Within the cell walls of wood lies a structural component called cellulose which has the potential to be a solution due to the high mechanical properties of the material (σ = 7.5 GPa and E = 110-220 GPa). Cellulose on the nanoscale is referred to as crystalline nanocellulose (CNC) and can be processed into thin films to be used as a suitable, sustainable replacement. Before CNC films can be implemented, proper mechanical characterization must be conducted. A technique utilizing buckling instabilities is identified as a solution, but cannot scale up to thicker films and conventional techniques struggle to deal with difficult CNC film properties. Free standing buckling mechanics are examined to present a viable solution for CNC film mechanical characterization. A novel mechanical testing frame was built to measure the critical buckling load of thin films. A cellulose acetate based transparent film was tested to find a critical load of 0.033N which yields an elastic modulus of 19.31 GPa. An overestimation was observed from insufficient equipment calibration and must be corrected before geometrical changes can be attributed to the transparencies to determine frame accuracy and precision. Once calibrated, CNC films will be tested to determine elastic moduli and anisotropy by varying load direction, crystal orientation, and crystal aspect ratio. Date: Tuesday, September 26, 2017 Time: 8:30 A.M. Place: ARMS 1021

1 0