ABSTRACT of Title "Dielectric Behavior of Epoxy Based Composites with Nanosized Alumina Fillers" A protocol for preparing composites with well dispersed nanometric fillers is first established. The uniform dispersion of particles is ensured using Scanning Electron Microcopy (SEM) and High-resolution Transmission Electron Microscope (HRTEM). In order to evaluate the nanodielectric, we investigate two important properties of the composites: degradation when exposed to surface discharges, and the complex dielectric permittivity. Laser Surface Profilometer is used to quantize the extent of degradation in the specimens. A mechanism is proposed by which degradation is resisted by nanofillers, and this is

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Nov 15, 2013 (3 years and 9 months ago)

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ABSTRACT of Title "Dielectric Behavior of Epoxy Based Composites with Nanosized Alumina Fillers"


A protocol for preparing composites with well dispersed nanometric fillers is first established. The
uniform dispersion of particles is ensured using Scanning

Electron Microcopy (SEM) and High
-
resolution
Transmission Electron Microscope (HRTEM). In order to evaluate the nanodielectric, we investigate two
important properties of the composites: degradation when exposed to surface discharges, and the
complex diel
ectric permittivity. Laser Surface Profilometer is used to quantize the extent of degradation
in the specimens. A mechanism is proposed by which degradation is resisted by nanofillers, and this is
corroborated by experimental evidence from Energy Dispersiv
e Xray analysis (EDX) and Atomic Force
Microscopy (AFM).


It is widely accepted by the research community that the interface between the polymer matrix and the
filler particles plays a major role in modifying the composite properties, both electrical and o
therwise. In
this work, we also examine the role of the interface by modifying the nanoparticle surfaces. In order to
investigate this effect, as received nanoparticles are pre
-
treated before nanocomposite preparation.
Pre
-
processing method used includes u
se of surfactants (Sodium dodecyl Sulfate), heating of particles
before use and functionalization of the particles with silane (3
-
glycidroxypropyltrimethoxy silane). It is
postulated that the presence of strong bonds between nanoparticles and epoxy, either

by hydrogen
bonding or covalent bonding, prevents erosion not only of the particles themselves but also of the
surrounding epoxy, thus increasing the resistance to surface degradation. The chemical interaction
between the fillers and epoxy is identified t
hrough Fourier Transform Infrared Spectroscopy (FTIR). A
combined experimental
-
numerical technique has been proposed to elicit important quantitative
information about the dielectric properties of the interphase region surrounding a nanoparticle
embedded i
n a polymer matrix. The method involves performing permittivity measurements through
dielectric spectroscopy and combining with concurrent unit cell based Finite Element solutions of the
equations of electrostatics. Finite element code was written with the

help of FORTRAN and MATLAB.



ABSTRACT of Title: Biomimetic Design of Composite Materials for Protective Structures



In modern times, engineered materials and structures are required to withstand multifunctional
loadings and service conditions. In order
to design protective composite structures, two major classes of
problems were studied. In the first case, impact protection in the ramming of animals was investigated.
The energy produced during the ramming of animals would be expected to result in undesir
able stress in
their frontal skull, which in turn would cause brain injury; yet this animal seems to suffer no ill effects.
The present study investigates the hypothesis that there is biomechanical relationship present between
the ramming event, structural

constituents of the horn and horn associated structures.


In the second case, layering observed in naturally occurring shells was studied. Over the past two
decades, interest in natural shells, particularly abalone shells, has increased due to unique
micr
ostructures and related toughness. But the studies reporting these unique properties are confined
to very selective shells. There exists a specific need to understand the behaviour of natural shells over
wide spectrum of the species. The goal in this work
is to broaden the knowledge ‐base of layering
occurring in natural shells. The efforts are made to understand the behaviour of these biological
materials from micro to macro scale, thereby allowing integration of these features into engineering
design.



B
IODATA:

Dr. Parimal Maity has done his B.E (Mechanical) from Jalpaiguri Govt. Engineering, Jalpaiguri, West
Bengal in 2002 and completed M.E (Machine Design) at Bengal Engineering and Science University,
Howrah, West Bengal in the Department of Mechanical
Engineering in 2004. He received his Ph.D.
degree from the Indian Institute of Technology Kanpur, India in the Department of Mechanical
Engineering in 2009. In the period from 2004 to 2009, his research was focused on dielectric behavior of
epoxy based com
posites with nanosized alumina fillers. He was a post ‐doctoral research associate (June
2009 ‐ July 2010) at Composite Vehicle Research Center in the Department of Mechanical Engineering,
Michigan State University, USA. He worked on the project “design of

composite structures for
lightweight, durable, and safe vehicle for air, ground, and marine transportation” funded by Office of
Naval Research (ONR) and U.S. Army Tank Automotive Research, Development and Engineering center
(TARDEC). His work was concentr
ated on modeling and experimental verification of the mechanics of

biological materials and structures and trying to mimic the key features of these to design high energy
absorbing composite materials. His research interests are nanodielectrics, multi
‐scale modeling of nano

‐composites, biomimetics/bio‐inspired design, high strain rate measurements, impact properties and
biocomposites. During his stay at Michigan State University he was mentor of under graduate students
and graduate students including
Ph.D. in this area.