December 2017 - Msepostdoc-list

ARMS policies
by Donna Bystrom 21 Dec '17

21 Dec '17

Everyone: FYI-----For the holidays the University will be closed December 25th through January 2nd. Staff is expected to report back to work on January 3rd unless vacation has been taken. During this time period the three eastern most doors of the building will remain unlocked. These doors are: next to the loading dock in the back of the building; off of Stadium Avenue, nearest to the elevators; and the door located off of Northwestern Avenue. The rest of the doors will remain locked. Also, I have been asked to send the following message. Apparently, someone is smoking cigarettes in the building. Cigarette butts have been found at the bottom of the east stairwell. The University policy is that smoking is prohibited in any University building. If you see anyone smoking in the building please ask them to step outside. I hope everyone has a wonderful and safe holiday. Donna

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Seminar Reminder for Temitope Aminu's Preliminary Exam: Seminar, Monday, Dec. 18, at 12:00, in ARMS 3115; Exam, same day, at 1:30, in ARMS 3001. " Design and Functionalization of Electrospun Polymeric Membranes with Metal-based Antimicrobial Capacity"
by Son, Rosemary E 15 Dec '17

15 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Design and Functionalization of Electrospun Polymeric Membranes with Metal-based Antimicrobial Capacity" By Temitope Q. Aminu Purdue MSE Ph.D. Preliminary Exam Advisor: Professor David F. Bahr ABSTRACT The pernicious spread of antimicrobial resistance in pathogenic microorganisms is a growing scourge, creating a virulent mutation of microbes impervious to prevailing treatments. Water, a necessary resource for most biological or physiological functions, is a hospitable habitat for many of these pathogenic microbes, being a medium for transmission to humans. Moreover, the ubiquity of these microbes makes possible water contamination after centralized treatment procedures. Nanoscopic antimicrobial metals are a reemerging disinfecting agent due to their toxic potency against various bacterial strains. Furthermore, polymeric fibers provide suitable anchoring and stability for metallic nanoparticles as well as a robust architecture for water filtration membranes. In light of these properties, incorporating metallic nanoparticles on polymeric fibers engenders functionally exotic composites for use as antimicrobial water treatment. In this review, we will discuss the electrospinning process in light of creating fibrous architectures for filtration membranes. Classically, fiber dimensions and morphology underpin filtration efficiency. This review will delineate factors modulating dimensions of electrospun fibers. In addition, mechanisms of metal-mediated toxicity in microorganisms as well as the expediency of metallic nanomaterials will be discussed. Additionally, the electroless deposition technique for nanoparticle immobilization on electrospun membranes will be discussed. Future research plan will be briefly presented against a backdrop of applicability of these composite membranes. Date: Monday, December 18, 2017 Time: 12:00 P.M. Place: ARMS 3115

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Seminar Notice for Michael Sakano's Preliminary Exam: Seminar, Friday, Dec. 15, at 9:00 a.m., in ARMS 1028; Exam, same day, at 1:30, in ARMS 2222. "Upscaling Molecular Dynamics Simulations for the Decomposition of High Energy Materials"
by Son, Rosemary E 15 Dec '17

15 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Upscaling Molecular Dynamics Simulations for the Decomposition of High Energy Materials" By Michael N. Sakano Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Alejandro Strachan ABSTRACT Typical molecular dynamics (MD) simulations for describing the chemical reactivity of high energy materials can only achieve up to a couple nanoseconds of data for systems on the order of a few hundred nanometers, due to their computational intensity. One solution is to implement the MD results as inputs into larger-scale models to allow for exploring chemical kinetics in sizable systems and for longer times. Two methods of interest are coarse-graining through Dissipative Particle Dynamics with constant Energy (DPDE) and continuum mechanics modeling using Gibbs formulation, both of which provide reactivities that closely mirror all-atom simulations. These methods are favored in terms of studying the behavior of high energy materials at experimental temperatures, where reactions take tens of microseconds to occur. This work reviews the DPDE and Gibbs formulation methods as a basis for modeling the chemical decomposition of nitromethane and RDX. Background for reactive molecular dynamics (RMD) and the force field of choice, ReaxFF, are discussed, as well as the theory behind each model. The core of the presentation focuses on implementing RMD data from homogenous decomposition into the two models, as well as comparing their kinetics behavior with our in-house simulations. Assumptions and limitations regarding both methods are presented last. So far in the literature, similar multiscale models have already been applied to thermal decomposition and shock simulations of high energy materials, where mechanical loading has been shown to accelerate chemistry. Preliminary results address the role of molecular disorder on reactivity in the context of 2-D thermal hot spots. Date: Friday, December 15, 2017 Time: 9:00 A.M. Place: ARMS 1028

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Seminar Reminder for Megan Kephart's Preliminary Exam: Seminar, Friday, Dec. 15, at 8:30 a.m., in ARMS 3115; Exam, same day, at 10:00, in ARMS 3001. "Mechanisms for Flash Sintering and Spark Plasma Sintering"
by Son, Rosemary E 13 Dec '17

13 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Mechanisms for Flash Sintering and Spark Plasma Sintering" By Megan R. Kephart Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Haiyan Wang ABSTRACT Field Assisted Sintering Technology (FAST) is a new sintering technique that is capable of sintering at much lower temperatures and much shorter times than conventional sintering. Flash Sintering and Spark Plasma Sintering are two types of Field Assisted Sintering Technologies that are discussed in this review. These new sintering techniques are compared to conventional sintering techniques. Conventional sintering mechanisms are introduced and compared to Spark Plasma Sintering and Flash Sintering mechanisms. Since Flash Sintering and Spark Plasma Sintering are relatively new technologies, there remain numerous unanswered questions about the processes. Although many mechanisms have been proposed for both Flash Sintering and Spark Plasma Sintering, the underlying mechanisms behind these sintering techniques are still under debate. Some Flash Sintering mechanisms proposed in literature are discussed and compared. Future research directions are proposed and could shed some light on the mechanisms involved. Date: Friday, December 15, 2017 Time: 8:30 A.M. Place: ARMS 3115

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Seminar Reminder for Alexander Strayer's Preliminary Exam: Seminar Wednesday, Dec. 13, at 8:30 a.m., in ARMS 3115; Exam, same day, at 10:00, in ARMS 2237. " Physiochemical Interaction of SiC with Si-Based Melts"
by Son, Rosemary E 12 Dec '17

12 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Physiochemical Interaction of SiC with Si-Based Melts" By Alexander R. Strayer Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Kenneth H. Sandhage ABSTRACT Silicon Carbide is an industrially important non-oxide ceramic because of its combination of chemical stability, thermal fatigue resistance, high stiffness, and low density. Additionally, SiC can be produced economically in near net-shape structures via liquid silicon melt infiltration into a silicon carbide/carbon porous preform. However, pure liquid Si and solid SiC cannot exist in equilibrium as there is a small amount of carbon solubility in liquid Si. Hence during infiltration dissolution of SiC in liquid Si is possible. In order to mitigate this problem, a better understanding of the physicochemical interaction between silicon carbide and liquid silicon melts is warranted. Here, a number of key publications are reviewed. Possible rate limiting steps for the dissolution are discussed, and major factors contributing to the kinetics such as poly-type, melt dopants, and atmosphere are explored along with current experiments and results aimed at filling the voids left in the literature on the topic. Date: Wednesday, December 13, 2017 Time: 8:30 A.M. Place: ARMS 3115

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Seminar Reminder for Alyssa Yaeger's Preliminary Exam: Seminar, Wednesday, Dec. 13, at 8:30 a.m., in ARMS 1028: Exam same day, at 10:00, in ARMS 3119. " Microstructural Evolution of Solder Due to Surface Finish Thickness"
by Son, Rosemary E 12 Dec '17

12 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Microstructural Evolution of Solder Due to Surface Finish Thickness" By Alyssa N. Yaeger Purdue MSE Ph.D. Preliminary Exam Advisors: Professors Carol A. Handwerker and John E. Blendell ABSTRACT With the drive toward lighter, thinner, and more capable electronics, smaller electronic components are always being created and used. However, this miniaturization of components leads to a miniaturization of solder joints as well, which can cause reliability concerns. Surface finishes such as Electroless Nickel Immersion Gold (ENIG) and Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) contain elements that form brittle intermetallic compounds (IMCs) with the tin in solder. A large volume percentage of these brittle IMCs leads to an inability to deal with environmental stresses, and poor reliability. These surface finishes have standardized thicknesses that have not changed as the average solder volume has decreased, leading to a larger percentage of plating elements present in the solder joint, and a larger volume fraction of IMCs. Annealing at temperatures near the melting point allows researchers to view the microstructural evolution of the solder at an accelerated rate, and can be crucial in determining the reliability of the solder joint over time. Date: Wednesday, December 13, 2017 Time: 8:30 A.M. Place: ARMS 1028

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Seminar Reminder for Keisuke Yazawa's Preliminary Exam: Seminar, Tuesday, Dec. 12, at 1:00, in ARMS 1028; Exam, same day, 2:30, in ARMS B197; "Electric Field Induced Strain and Switching Behavior in Ferroelectric Materials"
by Son, Rosemary E 11 Dec '17

11 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Electric Field Induced Strain and Switching Behavior in Ferroelectric Materials" By Keisuke Yazawa Purdue MSE Ph.D. Preliminary Exam Advisors: Professors Carol A. Handwerker and John E. Blendell ABSTRACT Ferroelectric materials have been used for actuator and sensor devices due to the electromechanical coupling property. The electromechanical coupling of ferroelectrics is attributed to piezoelectric lattice strain and polarization axis exchange (non-180o switching). It has been observed that non-180o switching plays a significant role in electric field induced strain. In addition, grain-grain interaction contributes to the effects in polycrystalline ferroelectrics. However, how the grain-grain interaction contribution affects non-180o switching is not fully understood yet. Recently, it has been observed that the grain-grain interaction induced a local elastic strain field due to inhomogeneous piezoelectric response throughout grains. Also, it has been confirmed that ferroelectric switching (180o switching) was hindered/facilitated by crystal distortion due to the elastic strain field. Considering the interaction mechanism, it can be expected that the elastic strain field by the grain-grain interaction can also influence non-180o switching, which contributes to electric field induced strain. Further experiments will be direct observations of non-180o switching and misorientation angle to a neighboring grain, which may affect the local elastic field. This experimental result will provide an insight for the grain-grain interaction contribution to the non-180o switching as well as a guideline for microstructure design for polycrystalline ferroelectrics to control the non-180o switching. Date: Tuesday, December 12, 2017 Time: 1:00 P.M. Place: ARMS 1028

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Seminar Notice for Temitope Aminu's Preliminary Exam: Seminar, Monday, Dec. 18, at 12:00, in ARMS 3115; Exam, same day, at 1:30, in ARMS 3001. " Design and Functionalization of Electrospun Polymeric Membranes with Metal-based Antimicrobial Capacity"
by Son, Rosemary E 08 Dec '17

08 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Design and Functionalization of Electrospun Polymeric Membranes with Metal-based Antimicrobial Capacity" By Temitope Q. Aminu Purdue MSE Ph.D. Preliminary Exam Advisor: Professor David F. Bahr ABSTRACT The pernicious spread of antimicrobial resistance in pathogenic microorganisms is a growing scourge, creating a virulent mutation of microbes impervious to prevailing treatments. Water, a necessary resource for most biological or physiological functions, is a hospitable habitat for many of these pathogenic microbes, being a medium for transmission to humans. Moreover, the ubiquity of these microbes makes possible water contamination after centralized treatment procedures. Nanoscopic antimicrobial metals are a reemerging disinfecting agent due to their toxic potency against various bacterial strains. Furthermore, polymeric fibers provide suitable anchoring and stability for metallic nanoparticles as well as a robust architecture for water filtration membranes. In light of these properties, incorporating metallic nanoparticles on polymeric fibers engenders functionally exotic composites for use as antimicrobial water treatment. In this review, we will discuss the electrospinning process in light of creating fibrous architectures for filtration membranes. Classically, fiber dimensions and morphology underpin filtration efficiency. This review will delineate factors modulating dimensions of electrospun fibers. In addition, mechanisms of metal-mediated toxicity in microorganisms as well as the expediency of metallic nanomaterials will be discussed. Additionally, the electroless deposition technique for nanoparticle immobilization on electrospun membranes will be discussed. Future research plan will be briefly presented against a backdrop of applicability of these composite membranes. Date: Monday, December 18, 2017 Time: 12:00 P.M. Place: ARMS 3115

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Seminar Notice for Megan Kephart's Preliminary Exam: Seminar, Friday, Dec. 15, at 8:30 a.m., in ARMS 3115; Exam, same day, at 10:00, in ARMS 3001. "Mechanisms for Flash Sintering and Spark Plasma Sintering"
by Son, Rosemary E 08 Dec '17

08 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Mechanisms for Flash Sintering and Spark Plasma Sintering" By Megan R. Kephart Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Haiyan Wang ABSTRACT Field Assisted Sintering Technology (FAST) is a new sintering technique that is capable of sintering at much lower temperatures and much shorter times than conventional sintering. Flash Sintering and Spark Plasma Sintering are two types of Field Assisted Sintering Technologies that are discussed in this review. These new sintering techniques are compared to conventional sintering techniques. Conventional sintering mechanisms are introduced and compared to Spark Plasma Sintering and Flash Sintering mechanisms. Since Flash Sintering and Spark Plasma Sintering are relatively new technologies, there remain numerous unanswered questions about the processes. Although many mechanisms have been proposed for both Flash Sintering and Spark Plasma Sintering, the underlying mechanisms behind these sintering techniques are still under debate. Some Flash Sintering mechanisms proposed in literature are discussed and compared. Future research directions are proposed and could shed some light on the mechanisms involved. Date: Friday, December 15, 2017 Time: 8:30 A.M. Place: ARMS 3115

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Seminar Reminder for Jonova Thomas's Preliminary Exam: Seminar, Monday, Dec. 11, at 11:30, in ARMS 1028; Exam same day, at 1:00, in ARMS 2222. " A Comprehensive Study on Neutron Irradiation Effects on Uranium-Zirconium Nuclear Fuel"
by Son, Rosemary E 08 Dec '17

08 Dec '17

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "A Comprehensive Study on Neutron Irradiation Effects on Uranium-Zirconium Nuclear Fuel" By Jonova Thomas Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Maria A. Okuniewski ABSTRACT Metallic U-10wt%Zr nuclear fuels are classified as potential fuels for fast breeder reactors as they possess a high fissile density and have increased compatibility with sodium, a frequently used reactor coolant. Despite their advantages when exposed to neutron irradiation in reactors, the fuels are subject to severe damage cascade and microstructural alterations. These microstructural alterations are also accompanied with large concentrations of point defects or defect clusters and fission products that cause severe fuel swelling. Void and bubble cavity growth can cause further swelling in fuels and facilitate the fuel to meet the cladding within which it has been enclosed. Contact between fuel and claddings at elevated temperatures and burnup cause fuel cladding chemical interactions (FCCI) to occur. FCCI is detrimental in reactor programs as they cause inter-diffusion between fuel and cladding constituents, which lead to eventual failure of the fuel. Previous studies on FCCI indicate that U-10wt%Zr fuels inhibit inter-diffusion to a certain extent by forming a Zr barrier between fuel and cladding. Although this may be true, most studies on FCCI done via isothermal diffusion studies between U-10Zr/HT9 fuel-cladding show varied observations on inter-diffusion layers formed and conflicting arguments on the process of formation of the Zr barrier that inhibits inter-diffusion. This report involves a detailed investigation on the swelling mechanism of irradiated U-10wt%Zr fuels and a discussion on the conflicting arguments of formation of the Zr barrier, and inter-diffusion layers. Finally, similarities between FCCI layers in neutron irradiated U-10wt%Zr/HT9 fuel-cladding is compared to observations made from isothermal diffusion experiments. Date: Monday, December 11, 2017 Time: 11:30 A.M. Place: ARMS 1028

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