Brown University Joint Materials/Solid Mechanics Seminar Series

Professors Masao Takeyama and Naoki Takata,
Grad Students Yusaku Hasebe and Imanuel Tarigan

Department of Metallurgy and Ceramics Science
School of Engineering
Tokyo Tech

Professor M. Takeyama:
“Introduction to Challenging Research on Materials Design using Intermetallics for Extreme Environment and Energy Applications – A-USC Power Plants and Elements Science and Technology Projects”

Grad Student Y. Hasebe:
“Phase Diagram Study on Fe-Ni-Nb Ternary System for Designing Novel Austenitic Heat-resistant Steels Strengthened by Fe2Nb and Ni3Nb Phases”

Grad Student I. Tarigan:
“Superior Creep Properties and Strengthening Mechanism by Laves Phase in the Novel Austenitic Heat Resistant Steels”

Assistant Professor N. Takata:
“Crystallography and Mechanical Properties of Fe2Al5 Intermetallic Layer –Replacement of Galvanizing with Al Coating in Steels”


Monday, December 6, 2010
2:30-4:00 pm
B&H Room 160

Seminar: AxSTREAM 3.0: Turbomachinery Design and Optimization Software

SoftInWay Inc
presents
Free Introductory Seminar:
AxSTREAM 3.0: Turbomachinery Design and Optimization Software

SoftInWay invites mechanical and aerospace engineers (students and professionals) to find out more about AxSTREAM 3.0 capabilities for conceptual design and optimization of turbomachinery flow path during the course of a free introductory seminar.
Date: September 14, 2010 Venue: 15 New England Executive Park, Burlington, MA, USA.
The latest version of AxSTREAM features new data structures which allow the modeling of turbomachinery flow path taking in account additional elements (ducts, heat exchangers, pressure valves etc). Other noticeable enhancements include a new preliminary design module with design space explorer, integrated profiling and 3D blade design, and a more efficient work environment.

To register, please contact us via marketing@softinway.com, indicating your name, company/university and country.

Event details are here:
http://softinway.com/education/turbomachinery-design-seminar.asp

Joint Materials/Solid Mechanics Seminar Series

“Microfluidic systems for Biochemical Analysis”

Sun Min Kim
Department of Mechanical Engineering
Inha University
Incheon, Republic of Korea

Wednesday, July 7, 2010
3:00-4:00 pm
B&H Room 190

Abstract:

In this seminar two components of microfluidic systems for biochemical analysis will be presented. Firstly, active and passive micromixer devices for protein sample pretreatment will be introduced. A simply fabricated microfluidic device that has a micro/nanochannel interface enhanced the active electrokinetic mixing of two fluid streams and a new passive micromixer which uses flow variation by microchannel geometry was also investigated by experimental and numerical studies.

Secondly, two novel protein preconcentration devices will be introduced. Sample preconcentration is a critical operation required for the determination of trace amounts of analytes of interest for which the concentration in the original solution is lower than the detection limits of the instrumentation. In this research, two novel techniques, embodied in microdevices, were created. A simple PDMS device was fabricated by weak bonding between PDMS and glass substrate. Upon application of electric fields, sample concentration is enhanced 103~106 – fold in 30 minutes. Another simple PDMS device using Temperature-Gradient Focusing (TGF) will be described. High electric potential applied to the device induced a temperature gradient within the microfluidic channel due to the channel’s variable-width, and analytes were focused at a specific location as a result of temperature-dependent species mobility.
These microfluidic devices can be a component of integrated Lab-on-a-chip systems for biochemical analysis.At the end, the current researches in our group will be briefly introduced.

FTCP Seminar: Professor Sung Jin Kim from Korea Advanced Institute of Science & Technology

Fluids, Thermal and Chemical Processes Group

Division of Engineering and Center for Fluid Mechanics

Professor Sung Jin Kim
Department of Mechanical Engineering
Korea Advanced Institute of Science & Technology
Modeling and Sensing Techniques for
Thermal Analysis of Microsystems

Thursday June 10, 2010
Barus & Holley Room 190
11:00 AM

Abstract

The development of micro/nano fabrication technology has enabled the size of many engineering devices to shrink significantly over the past two decades. Among these are many micro thermal systems where fluid flow and heat transfer play an important role. These include micro heat exchangers, micro heat pipes, micro total analysis systems, micro pumps, ink jet heads, and so on.

This talk is intended to present a method for modeling transport phenomena in microstructures. It is followed by three types of micro-sensors developed for experimental investigation of fluid flow and heat transfer in microstructures. The modeling technique based on the averaging method is applied to thermal design and optimization of a microstructure. The micro-sensors can be used to measure the temperature distribution at the surface of a microstructure and the mass flow rate passing through it. Some of the latest micro thermal systems will be discussed with examples of application.

Presentations by Molecular Nanophotonics Group at ICFO

Five Short Presentations by the
Molecular Nanophotonics Group at
ICFO - The Institute of Photonic Sciences (Barcelona, Spain)

Thursday, June 10th
10:30am in Barus and Holley 751

Professor Niek van Hulst: Overview of Nanophotonics Research at ICFO

Daan Brinks: Femtosecond Phase Control of Hot Spots at a Coupled Antenna

Alberto Curto: Single Quantum Dot Emission Close to a Metal Rod Antenna

Dr. Martin Kuttge: Non-Linear Nanostar Plasmonic Ruler

Dr. Riccardo Sapienza: Photonic Mode Density Probed by Single Molecule Approaches

Brief Biography: Niek van Hulst obtained his PhD in Molecular and Laser-physics at the University of Nijmegen (the Netherlands). In 1990, he became an Assistant Professor at the University of Twente, and in 1997, he became full Professor in Applied Optics, at the MESA+ Institute for NanoTechnology (Enschede, the Netherlands). In 2005, he joined ICFO – the Institute of Photonic Sciences (Barcelona, Spain) as ICREA Research Professor and senior group leader in the area of NanoPhotonics. Professor van Hulst is the author of over 200 refereed papers on single molecule detection, near-field optics, ultrafast laser spectroscopy, non-linear optics, macro/biomolecules, atomic force microscopy, nanophotonic structures and photonic crystals. Professor van Hulst has also been the recipient of a 1997 Shell Research Stimulation Award, 2003 Körber European Science Award, and 2009 Advanced Investigator Award of the European Research Council.

Seminar: "Surface Modification of Electrospun Micro-/Nano-Fibers for Protein Delivery"

ENGINEERING / BIOMATERIALS SEMINAR
Surface Modification of Electrospun Micro-/Nano-Fibers for Protein Delivery

Dhirendra S. Katti, Ph.D.
Department of Biological Sciences and Bioengineering
Indian Institute of Technology – Kanpur, INDIA

Friday, June 4, 2010
B&H Room 190
2:00 p.m.

Abstract

Poly (l-lactide-co-glycolide) (PLGA) has been widely explored as scaffolds in tissue engineering. However, its hydrophobicity can adversely affect events such as protein adsorption and downstream cell adhesion in tissue engineering applications. Although surface modification techniques (high energy radiation / chemical treatment) to modify the hydrophobicity of PLGA can be useful at the macroscopic scale, their usefulness for micro-/ nano-meter scale objects can be limited due to adverse affects on physical properties. In this talk, I will present some of our recent studies on the surface hydrophilization of electrospun micro-/nano-fiber meshes of PLGA (85:15) by using the following techniques - blending with small quantities (0.5-2%) of a non-ionic surfactant Pluronic® F-108 (PF-108), mild chemical treatment and mild photo-chemical methods.

Seminar: "Optical Antennas for Single Emitters"

Optical Antennas for Single Emitters
Tim H. Taminiau, ICFO - The Institute of Photonic Sciences (Barcelona, Spain)

Thursday, June 3rd
4pm in Barus and Holley 190

Brief Biography: Tim Taminiau is a visiting researcher in the Division of Engineering at Brown University. Tim received his M.Sc. in Applied Physics from the University of Twente in 2005, and is currently completing his Ph.D. with Professor Niek van Hulst at the Institut de Ciències Fotòniques (ICFO) in Barcelona, Spain. During his graduate studies, Tim has also had visiting appointments at the California Institute of Technology and the Korea Institute of Machinery and Materials (KIMM). In 2008, Tim gave a keynote presentation at the 10th International Near-Field Optics Conference, and in 2009, he was an invited speaker at the SPIE Optics and Photonics Meeting and the Spring Meeting of the Materials Research Society (MRS). His extensive work on enhancing and redirecting single molecule and quantum dot emission with optical antennas has been published in Nano Letters, Nature Photonics, and Physical Review Letters.

Seminar: Active Hardware Metering for IP Protection and Security

ESCE Seminar Speaker
Professor Farinaz Koushanfar, Rice University
Title: Active Hardware Metering for IP Protection and Security
Date & Location: Friday April 21th 3:00pm-4:00pm at B & H 190

Biography:

Farinaz Koushanfar is an Assistant Professor of Electrical & Computer Engineering and Computer Science at Rice University, where she also directs the Texas Instruments DSP Leadership University Program.
Before joining Rice in 2006, she received her Ph.D. in Electrical Engineering and Computer Science and her M.A. in Statistics both from the University of California, Berkeley. Her research is focused on developing techniques for synthesis and management of customizable, adaptive, lightweight, and secure embedded systems, adaptive energy delivery, and applications of emerging technologies. Koushanfar is a recipient of an Office of Naval Research (ONR) Young Investigator Program (YIP) Award, a National Science Foundation (NSF) CAREER Award, a Defense Advanced Research Projects Agency (DARPA) Young Faculty Award, an INTEL Open Collaborative Research (OCR) Fellowship, and a Mobicom Best Paper Award. In 2008, she was named one of MIT Technology Review's young innovators under 35 (TR-35).

Abstract:

I will present novel lightweight hardware-based mechanisms for ensuring security, intellectual property (IP) protection, and trust of integrated circuits (ICs) and systems. The need for the new security methods stems from the proliferation of the fabless semiconductor business model, increase of third-party IP reuse, emergence of personal security devices, and the high overhead of traditional cryptographic protocols for embedded systems. The focus of the talk will be on active hardware metering, a first system of security mechanisms and protocols that enable the design house to gain active post-fabrication control of each produced IC, their properties and terms of use, or by run-time disabling of ICs in case of tamper detection. Active hardware metering is built upon two basic
mechanisms: (i) variability-based uniqueness of each chip, and (ii) alteration of the design structure so that the initial functionality is preserved but integrated with the unique chip properties through functional access points. Thus, not only each IC has a specific signature, but also its functionality requires a unique access code for activation. For anybody without authorization from the design house, each chip would be effectively and uniquely locked. To realize the first mechanism, we use physical unclonable functions (PUFs) that overcome the digital storage vulnerabilities. I discuss our ongoing work in security analysis, safeguarding, implementation, and fabrication of new families of PUFs, and their use in secure system design. For the second mechanism, I show how modification of the functional description is accomplished through modifying the finite state automata. Attacks and countermeasures are discussed.
Experimental evaluations of hardware metering on benchmark designs and proof-of-concept hardware implementation on H.264 demonstrate the low overhead, security, and practicality of the new techniques.

Host: Professor Sherief Reda

Electronics and Photonics Seminar with John Weiner

Division of Engineering
“Electronics and Photonics Seminar”
Extraordinary optical transmission revisited:
how light gets through isolated or periodic arrays of
subwavelength slits and holes (or not)

Prof. John Weiner
Center for Nanoscale Science and Technology (CNST)
National Institute of Standards and Technology (NIST)
Gaithersburg, MD USA

Thursday, May 6th
12:45pm in Barus & Holley 751
(pizza and sodas will be offered)

Abstract: The passage of light through apertures much smaller than the
wavelength of the light has proved to be a surprisingly subtle phenomenon.
This talk describes how modern developments in nanofabrication, coherent
light sources and numerical vector field simulations have led to the upending
of early predictions from scalar diffraction theory and classical
electrodynamics. Optical response of real materials to incident coherent
radiation at petahertz frequencies leads to unexpected consequences for
transmission (and extinction) of light through subwavelength aperture arrays.

Biosketch: John Weiner is a CNST Visiting Fellow in the Nanofabrication Research
Group. He is Professeur Èmèrite from the Université Paul Sabatier in Toulouse, France.
John received a Ph.D. from the University of Chicago in Chemical Physics. Following
postdoctoral studies and a lectureship at Yale, he joined the faculty at Dartmouth College.
Later, John spent a year as visiting professor at the Laboratoire des Collisions Atomiques
et Moléculaires at Orsay, France, returning to the US to join the faculty at the University
of Maryland, where he investigated atomic collisions at submillikelvin temperatures
achieved by optical cooling techniques. After two decades at Maryland, John returned to
France, where he became interested in light localization by plasmonic structures. At the
CNST, he is working with Henri Lezec on the design, fabrication, and characterization of
nanoscale optical resonator arrays.

Joint Materials/Solid Mechanics Seminar Series with Prof. Gui-Rong Liu

BROWN UNIVERSITY
Joint Materials/Solid Mechanics Seminar Series

“Computational methods for certified solutions, adaptive analysis, real-time computation, and inverse analysis of engineering systems”

Friday, April 30, 2010 4:00-5:00 pm B&H Room 751

Prof. Gui-Rong Liu
Deputy Head of Mechanical Engineering
National University of Singapore

Abstract:

Rationale: Engineering systems become more and more sophisticated. Computer modelling for such systems is a must for optimal design, healthy monitoring, NDE, existing strength assessments, and service life prediction. The necessary requirements for an effective computational method have now become stability, convergence, automation, solution certification, adaptation, and real-time computation.
Theory: This talk introduces first the basic theory for a unified formulation of a wide class of compatible and incompatible methods based on FEM and meshfree settings. Important properties and inequalities for G spaces are proven, leading to the so-called weakened weak (W2) formulation that guarantees stable and convergent solutions. We then present some possible W2 models that meet all these challenges: 1) linear conformability ensuring the stability and convergence; 2) softening effects leading to certified solutions and real-time computational models; 3) insensitivity to the quality of mesh allowing effective uses of triangular/tetrahedral meshes best suited for automatic adaptive analyses.
Applications: A large number of benchmarking examples and practical examples will be presented to examine the theory and various numerical models, including material behavior at various extreme situations, dynamic behavior and interactions of red blood cells, inverse identification of material properties and cracks in engineering structural systems, and integrity assessment of dental implant systems via inverse analysis with real-time computation.

Center for Fluid Mechanics Seminar Series with Marcos

CENTER FOR FLUID MECHANICS AND THE FLUIDS, THERMAL AND CHEMICAL PROCESSES GROUP
OF THE DIVISION OF ENGINEERING
SEMINAR SERIES
Marcos
Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA

TUESDAY, April 27, 2010
APPLIED MATHEMATICS BUILDING
182 GEORGE STREET
ROOM 110
4:00pm

Bacteria in Shear Flow
I present a combined experimental and theoretical analysis of a bacterium exposed to a shear flow. I start by addressing the role of chirality in shear, motivated by the helical shape of some bacterial species (e.g. spirochetes) and of the flagella of all motile bacteria. While non-chiral objects at low Reynolds numbers faithfully follow streamlines, our model based on Resistive Force Theory predicts that the coupling of chirality and shear results in a lift force, which induces a drift perpendicular to the shear plane. We verified this prediction experimentally by exposing spirochetes to a plane parabolic flow in a microfluidic channel and tracking their lateral position by videomicroscopy. This method can be used to separate microscale chiral objects of opposite handedness when shear is larger than rotational Brownian diffusion, providing hope for a straightforward approach for the separation of chiral molecules, of considerable interest in the food and pharmaceutical industries. By tracking individual bacteria in microchannels, we find that shear alters bacterial swimming patterns and in particular reduces their ability to move across streamlines. This results from the bacteria undergoing Jeffery orbits, which bias cell orientation in the direction of the flow and hamper cross-streamline swimming. This can in turn hinder chemotaxis and thus have a significant negative effect on bacteria foraging. Finally, a separate set of experiments shows that bacteria do not alter their swimming behavior in response to shear: nature has apparently not deemed it worthwhile to develop a shear sensor at the micrometer scale.

Center for Fluid Mechanics Seminar Series with Michael Berhanu

CENTER FOR FLUID MECHANICS AND THE FLUIDS, THERMAL AND CHEMICAL PROCESSES GROUP
OF THE DIVISION OF ENGINEERING
SEMINAR SERIES

Michael Berhanu
Coworkers : Darija Cosic and Pr. Arshad Kudrolli
Clark University, Department of Physics, Worcester, MA

TUESDAY, MAY 11, 2010
APPLIED MATHEMATICS BUILDING
182 GEORGE STREET
ROOM 110
3:00pm

Granular Aggregates with Capillary Interactions We consider assembly of identical spherical particles (of diameter about 3 mm) floating on the surface of a viscous liquid. Interface deformation and gravity create attractive interactions between particles, leading to capillary aggregation. Firstly, features of this phenomena are experimentally investigated for a small number of particles to understand self-organization of floating spheres. Then for a large number of particles, density is homogeneously increased. Dense aggregates are formed and we investigate structure of such a cohesive granular medium as a function of area fraction. Using Voronoi tesselation, heterogeneity is characterized. Moreover significant short range order is found, by computing pair correlation function and orientational order parameter. This two-dimensional example demonstrates that structure of an athermal system of attractive particles contrasts strongly with the cohesionless case. When density is increased, heterogeneity decreases and steric effects become more important compared to attraction of particles. Finally jamming transition is reached, inducing the buckling of the aggregate.

“Scale and Time Dependent Mechanics of Polymeric Nanofibers”

BROWN UNIVERSITY
Joint Materials/Solid Mechanics Seminar Series

“Scale and Time Dependent Mechanics of Polymeric Nanofibers”

Prof. Ioannis Chasiotis
Department of Aerospace Engineering
University of Illinois at Urbana-Champaign

Abstract:

The mechanical response of polymeric nanostructures as a function of size and strain rate is largely unexplored. This seminar will elaborate on the mechanical behavior of electrospun polymeric nanofibers at strain rates 10-4 - 200 s-1 as a function of their diameter and fabrication conditions. The experiments were conducted via MEMS tools in conjunction with digital image correlation motion tracking, which allowed for high resolution measurements in force and nanofiber extension. The advantage of this method lies with the ability to carry out nanoscale experiments in ambient conditions, contrary to commonly followed practices that require imaging with electron microscopy. The elastic modulus and the tensile strength of nanofibers with diameters between 200-800 nm varied by a factor of seven with fibers in the range of 200-300 nm resulting in the highest property values. Thinner fibers that demonstrated the highest mechanical strengths were characterized by molecular alignment which was confirmed by Fourier transform infrared spectroscopy. Most mechanical properties varied monotonically in the aforementioned range of strain rates, while they were a strong function of the nanofiber diameters and the necking instabilities occurring during the tensile experiments. These results supported the optimization of the fabrication method of electrospinning in order to produce amorphous polymeric nanofibers with true ultimate tensile strength as high as 900 MPa and ductility exceeding 200% at most applied strain rates.

Monday, April 19, 2010 - 4:00-5:00 pm - B&H Room 190

Alumni Profile in Person: Oscar Groome

Mr. Groomes will discuss the important process of selecting your first job and then examine the importance of both a technical and a business skill set to your job trajectory.
Monday, March 1, 2010 – 4:00-5:00pm - Barus and Holley 190

“Bio-Inspired Structural Materials” Seminar

Joint Materials/Solid Mechanics Seminar Series

“Bio-Inspired Structural Materials”

Robert O. Ritchie

Department of Materials Science and Engineering, University of California Berkeley

and

Materials Sciences Division, Lawrence Berkeley National Laboratory

Abstract:

The structure of materials invariably defines their mechanical behavior.  However, in most materials, specific mechanical properties are controlled by structure at widely differing length scales.  Nowhere is this more apparent than with natural materials.  Bone and nacre, for example, are complex composites whose unique combination of mechanical properties derives from an architectural design that spans nanoscale to near-macroscopic dimensions. Unlike engineering composites where properties are invariably governed by the rule of mixtures, the mechanical properties of natural composites are generally far greater than their constituent phases. Here we describe an approach to developing bulk ceramic-polymer nacre/bone-like structural materials with unprecedented strength/toughness properties.  We attempt to emulate Nature using a freeze-casting process to make materials through the combination of two ordinary compounds, alumina and PMMA, into ice-templated structures with exceptional fracture toughness, an order of magnitude higher than that of their constituents.  The final products are bulk lightweight hybrid ceramic-based materials whose high specific strength and toughness properties are comparable to aluminum alloys. 

Monday, March 8, 2010         4:00-5:00 pm                     B&H Room 190

Joint Materials/Solid Mechanics Seminar Series

Joint Materials/Solid Mechanics Seminar Series

“Simulations of projectile impact on ceramic”

Prof. R. M. McMeeking
Department of Mechanical Engineering and Materials Department
University of California, Santa Barbara

Abstract:
We have developed a new constitutive law for ceramic based on the growth of wing cracks under compression, in which it is recognized that these cracks can be closed under pressure. Thus a damaged material under severe compression regains its undamaged strength. In such states of triaxiality, with some degree of deviatoric stress, plastic flow due to dislocation motion or twinning can occur independently of brittle damage. This phenomenon is allowed for in our model, which involves viscoplasticity as well as a brittle damage accumulation. In tension, the material readily cracks and is weak. In compression, the growth of brittle damage causes comminution of the ceramic, and in such circumstances a Mohr-Coulomb inelastic behavior develops to represent the granular flow of the rubblized material. The model is valid at low strain rates, and can be used to model static indentation of ceramic by a hard sphere, used for calibration purposes. Data for the dynamic impact of metal spheres on the ceramic are also used to calibrate the model. The constitutive law is then used to simulate the deep penetration of tungsten rods into SiC (the Lundberg experiment) and the impact of steel cylinders on trilayers of steel/ceramic/steel.

Monday, February 15, 2010 4:00-5:00 pm B&H Room 190

Note: There will be a dinner for Prof. McMeeking after the seminar.
Please contact Ms. Pat Capece at x1501 if you wish to attend.