Updated on 12 Sept 2004
NANO-2004
NANO 2004 India
Chair :
Dr Sri
Bandyopadhyay University of New South Wales,
Advisor : Prof
Sudipta Seal, AMPAC,
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Keynote & Invited
Presenters expected to attend & Paper Titles / Abstracts, as on
Keynote Lectures :
1. Professor
Martin A. Green, UNSW
"Nanomaterials for Photovoltaic
Applications
Executive
Research Director
Centre of
Excellence for Advanced Silicon Photovoltaics and Photonics
Web:
http://www.pv.unsw.edu.au
Facsimile: +61-2-9662-4240
SYDNEY,
N.S.W. 2052,
NANOMATERIALS FOR PHOTOVOLTAIC
APPLICATIONS
Abstract
To provide a viable “third alternative” to fossil fuels and nuclear energy as the basis of future energy supplies, photovoltaics needs to evolve from its present dependence on bulk silicon wafers to technology based on high performance, low-cost thin-films. Nanomaterials offer scope for progress in this area. Work in the author’s group on the development of artificial semiconducting materials of variable bandgap using silicon quantum dots in an amorphous dielectric matrix will be described as will other possible areas where nanomaterials may provide a solution to the above challenge.
Brief Biography
: Professor MARTIN A. GREEN
Martin Green is
currently a Scientia Professor at the University of New South Wales, Sydney,
Australia and Executive Research Director of the University's Centre of
Excellence for Advanced Silicon Photovoltaics and Photonics. He is also
Research Director of Sydney-based Pacific Solar Pty. Ltd., a company
established specifically to commercialise the University’s polycrystalline
silicon thin-film solar cell technology.
Born in Brisbane and educated at the University of Queensland and then
McMaster University, Canada, his group's contributions to photovoltaics are
well known internationally, and include the improvement of silicon solar cell
performance by over 50% over the past 15 years.
Major international
awards including the IEEE William R. Cherry Award in 1990, the 1995 IEEE J.J.
Ebers Award, the 1999 Australia Prize, and the 2002 Right Livelihood Award,
also known as the Alternative Nobel Prize, for “dedication and outstanding
success in responding to the key technological challenge and moral imperative
of our age: the harnessing of solar
energy”. Professor Green is a Fellow of
the Australian Academy of Science, the Australian Academy of Technological
Sciences and Engineering and The Institute of Electrical and Electronic Engineers. He is the author of six books on solar cells,
several book chapters, numerous reports and papers in international refereed
journals in the area of semiconductor properties, microelectronics and
optoelectronics, including solar cells.
His interest in nanotechnology arises from its possible application to
high performance photovoltaic devices and to silicon photonics.
2. Prof Marie-Isabelle Baraton, SPCTS-UMR , FRANCE
Dr Marie-Isabelle BARATON SPCTS –
UMR CNRS 6638
Faculty of
123 Avenue Albert Thomas F-87060
Tel: + 33 555 45 7348 Fax: +33 555 77 8100 Fax: +33 555 77 8100
E-mail: baraton@unilim.fr or
ceramec@wanadoo.fr
Contribution of FTIR Spectroscopy to the
Understanding of the NOx Detection Mechanism by Semiconductor Metal
Oxides : - Marie-Isabelle BARATON, SPCTS - UMR
CNRS, University of Limoges, France;
Lhadi MERHARI, CERAMEC R&D, Limoges, France e-mail: baraton@unilim.fr
Lhadi MERHARI, CERAMEC R&D,
Abstract
It becomes more and more critical to rapidly
and efficiently monitor the level of nitrogen oxides (NO and NO2)
because these gases are particularly harmful to the environment. These primary
pollutants are indeed responsible for generating ozone. Although precise
instruments for air quality monitoring are installed in most of large cities,
their prohibitive costs prevent establishing a dense network, which would
constitute a solution for efficient identification and tracking of pollutant
emission sources. To decrease the cost of the devices for nitrogen oxides
detection in both outdoor and indoor atmospheres, we consider using chemical
sensors based on semiconductor metal oxides. It has indeed been known for a
long time that semiconductor metal oxides can be used for nitrogen oxides
detection but the gas detection mechanism is still unclear. To improve the
performance of semiconductor sensors fabricated by screen-printing technology,
nanosized particles are used to make the thick-film sensitive layer. Although
an optimised fabrication procedure has been developed, leading to both an
increase of the sensor sensitivity and a dramatic decrease of the detection
thresholds, fundamental improvements cannot be obtained without understanding
the gas detection mechanisms. In previous works, we have proved that Fourier transform
infrared (FTIR) spectroscopy is a high-performance tool to investigate the
surface chemical composition of semiconductor nanosized particles and to follow
the chemical reactions at their surface while simultaneously monitoring the
induced changes in the electrical conductivity.This work essentially reports
the results obtained by FTIR spectroscopy on tin oxide and indium oxide
nanoparticles when nitrogen oxide is adsorbed. The sensitivity of these two
metal oxides and the chemical reactions occurring under NO/NO2
adsorption are studied versus the different surface reactivities of the
semiconductor nanoparticles.
Brief
Biography : : Dr Marie-Isabelle Baraton, Ph.D; D.Sc.; Habil.
Senior
scientist, Dept of Ceramics (SPCTS, UMR CNRS), leading research on
nanostructured materials at the U Limoges, France where she received her Ph.D.
in physics and her Doctorate in Science; obtained a NATO grant to conduct
fundamental research on infrared surface characterization of nanosized powders
and on Langmuir-Blodget films at the University of Ottawa, and at the Lash
Miller Laboratories in Toronto, Canada. Baraton’s current research interests
include the physical-chemistry of nanomaterial surfaces as well as theoretical
and experimental studies of chemical reactions at gas-nanomaterials
interfaces. Baraton has authored over
100 refereed papers, communications and book chapters; editor of several books
on nanomaterials including a recently published book on functionalization of
nanoparticles. She was the initiator and the coordinator of two European
projects (FP4 and FP5). She led the two European Consortia comprising
industries, research centers and universities working on novel gas sensors
based on semiconductor nanomaterials for air quality monitoring. Baraton is
the founder and the President of a private research center CERAMEC dedicated to
the applications of nanomaterials; has organized international conferences
on nanomaterials and she was one of the three Meeting Chairs of the Fall 2002
Materials Research Society (MRS) meeting in
Invited speakers
2. Prof Hiroshi Amekura, NIMS,
Magnetic Transitions observed in Nickel
nanoparticles in SiO2 fabricated by ion implantation : H. Amekura, Y. Fudamoto,
Y. Takeda and N. Kishimoto Nanomaterials Laboratory, National Institute for Materials Science,
3-13 Sakura, Tsukuba, Ibaraki 305-0003, , Japan e-mail:amekura.hiroshi@nims.go.jp
Keywords: metal nanoparticle, ion implantation,
non-magnetic to magnetic transition, Curie transition, superparamagnetism
Prof Hiroshi Amekura, NIMS,
Abstract
Magnetic metal nanoparticles
dispersed in insulators draw much attention, because of applicability for super
high-density data storage, tunneling magnetic resistance devices, etc.
Negative-ion implantation (NII) is one of the promising methods to fabricate
metal nanoparticles in insulators, with fairly good controllability in
position, depth and dose of implanted ions, without surface charging. Up to
now, we have succeeded in fabricating several species of metal nanoparticles
(Cu, Ag, Au, Ni, V, ...) in amorphous SiO2 and some other
insulators. In this talk, magnetic and optical properties of Ni nanoparticles
in SiO2 fabricated by the NII method are reviewed, focusing on (1)
fundamental characteristics of the Ni nanoparticles fabricated by the NII
method, (2) non-magnetic to magnetic transition during aggregation and (3) the
Curie transition of the nanoparticles with increasing temperature.
Nickel nanoparticles
were fabricated by implantation of Ni negative-ions of 60 keV to silica glass
substrates (SiO2). Optical absorption spectra of the implanted
samples show two broad peaks at 3.2 and 5.8 eV, which indicate the formation of
metallic Ni nanoparticles in SiO2. The cross-sectional TEM
observation confirms the formation of the nanoparticles whose diameter is 2.9 ± 1.0
nm, within a surface layer of ~100 nm thick. Magnetization curves are well
fitted with the Langevin function without hysteresis at room temperature,
indicating superparamagnetic nanoparticles. Temperature dependences of
magnetization under zero-field and field (0.3 kOe) coolings were measured from
5 to 300 K. Although the FC-magnetization shows a monotonic increase down to 5K
with decreasing the temperature, the ZFC-magnetization turns to a decrease
below 27 K. This observation confirms the formation of the superparamagnetic Ni
nanoparticles.
In the NII method, nanoparticle formation is
governed by aggregation of implanted ions via enhanced diffusion under
implantation or heat treatment. When the samples are annealed from 400 to 1000°C in
vacuum, the optical absorption and the magnetization show different annealing
temperature dependences each other. Although the absorption, which monitors a
metallic nature of Ni nanoparticles, shows almost no change up to 900°C,
the magnetization, which monitors a magnetic nature of Ni nanoparticles, shows
a drastic increase around 800°C. The blocking temperatures of
the superparamagnetic nanoparticles show the same behaviors as the
magnetization.
Brief
Biography : Prof Hiroshi Amekura
Dr. Hiroshi
AMEKURA is a senior researcher of Nanomaterials Laboratory, National Institute
for Materials Science (NIMS),
2. Dr Pushan Ayub : TIFR
3. Dr Sri
Bandyopadhyay UNSW,
School of Materials Sci & Eng, The University of New South
Wales, Sydney 2052, Australia; Phone +61
2 9385 5956, Mobile +61 414 751 755, Fax +61 2 9385 5956, e-mail s.bandyopadhyay@unsw.edu.au
EFFECT
OF SURFACTANT CONCENTRATION ON THE SIZE AND SURFACE ROUGHNESS OF CERIA
NANOPARTICLES AS STUDIED BY TEM AND AFM
Sushil Gupta,1Peter Brouwer1, Sri Bandyopadhyay1, Swanand Patil2 R. Briggs*, and Sudipta Seal2
1School
of Materials Science and Engineering, The
2Department Advanced
Materials Processing and Analysis Centre, University of Central Florida, FL
32816,
* NSF REU
student: Rochester Institute of Technology
Abstract: A series of ceria nanoparticles were synthesized by using microemulsion method using sodium bis(2-ethylhexyl) sulphosuccinate (AOT) as a surfactant. The effect of relative concentration of surfactant on the size and surface roughness of ceria particles was examined by using transmission electron microscopy (TEM) and atomic force microscopy (AFM) respectively. For TEM examination, a small amount of ceria powder was suspended in ethanol followed by dripping onto the surface of a carbon coated copper grid and air-drying. For the AFM examination, ceria-ethanol suspension was dripped on to carefully prepared thin mica sheet stuck on glass plate followed by evaporating ethanol. The investigation confirmed relationship between the size and roughness properties of the ceria particles as a function of the water to surfactant ratio. With increasing dilution of surfactant, the size distribution became narrow such that average particle size decreased linearly as the ratio increased with out affecting lower threshold value of particle size (~ 10 nm). The surface roughness, on the other hand was found to increase linearly with increasing water to surfactant ratio implying diluted surfactant would give rougher surface of the nanoparticles. The information can be used to tailor the adhesion properties of ceria particles by optimizing the size distribution as well as surface roughness.
KEYWORDS: cerium oxide nanoparticles, surfactant, size, surface roughness, AFM, TEM.
Brief
Biography : Dr. Sri Bandyopadhyay
Education : Ph.D 1974 – 1978 Monash University (Materials Eng /Polymer Eng): Supervisor : Prof Hugh Brown ; Master’s (Materials Science) IIT Kanpur, India 1971 - 1973; sup : Prof P N Murthy; Bachelor’s[Met Eng, IIT Kharagpur, India 1963 - 1968
Field of research : Micro-macro
correlation in materials; Fracture mechanisms, Polymer matrix, metal matrix and
cement matrix composites, Natural fibre/matrix/composites; Developing wood
substitute natural composites; Nanomaterials research in collaboration with UCF
Current Appointment : 1991 - Senior Lecturer,
Employment History 1980 – 1990 Research Scientist/Senior Research Scientist : DSTO, Materials Res Lab, Melbourne 1978 - 1980 Materials Scientist, Australian Dental Standards Lab, Abbotsford, Victoria, 1969 – 1974, Materials Engineer/Senior Materials Engineer, Indian Space Research Organisation, Trivandrum; 1968 – 1969 : Bhabha Atomic Research Centre Training School, Bombay India
Honors/ Awards: Recipient 1983 – 84 Best
Scientist Award DSTO MRL Melbourne for in-situ deformation and fracture
experiments in the chamber of a scanning electron microscope. Invited visiting professor a) the Polymer
Lab, EPFL Lausanne, Switzerland, and b) Center for Composite Materials, U
Delaware,
Organiser/Chair of ACUN International Composites Conference series at UNSW; so far ACUN-1 to ACUN-4 held; ACUN-5 in 2005.
4.
Prof Dr V Basiuk,
Instituto
de Ciencias Nucleares, Universidad Nacional Autónoma de México (UNAM),
Circuito Exterior C.U., 04510 México, D.F., Mexico; e-mail: basiuk@nuclecu.unam.mx
A). Solvent-free
derivatization of carbon nanotubes with amines Vladimir
A. Basiuk1 and Elena V. Basiuk2
Abstract
Solvent-free derivatization of carbon nanotubes with amines
Vladimir A.
Basiuk1 and Elena V. Basiuk2
1 Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (UNAM),
Circuito Exterior C.U., 04510 México, D.F., Mexico; e-mail:
basiuk@nuclecu.unam.mx
2 Centro de Ciencias
Aplicadas y Desarrollo Tecnológico, UNAM,
Circuito Exterior C.U., 04510 México, D.F., Mexico; e-mail: elenagd@servidor.unam.mx
Keywords: Carbon nanotubes;
single-walled; multi-walled; oxidized; closed caps; derivatization; amidation;
amination
Abstract
The solvent-free gas-phase technique, employed earlier
for the chemical derivatization of inorganic materials (e.g. silica), is
proposed as a simplified and convenient method of the carbon nanotube (CNT)
derivatization with aliphatic amines. Being carried out under elevated
temperatures (>150°C), it requires no additional chemical activation; it is
relatively fast (0.5–2 h); excess of the derivatizing reagent is spontaneously
removed from the reaction zone; and there is no need to use an (organic)
solvent medium. The latter feature not only is attractive from an ecological
point of view, but also helps to avoid undesirable particle aggregation of the
material derivatized.
We first employed the gas-phase derivatization
procedure for direct (i.e., without chemical activation of terminal carboxylic
groups) amidation of oxidized single-walled carbon nanotubes (SWNTs). The
procedure included treatment of SWNTs with amine vapors under reduced pressure
and a temperature of 160–170ºC. Applicability of infrared (IR) spectroscopy for
chemical characterization of the derivatized SWNTs was analyzed. It was
concluded that IR spectra of oxidized SWNTs treated with amines under different
conditions (described here and elsewhere) cannot correspond to amide
derivatives on SWNT tips, due to a very low concentration of the terminal
groups relative to the whole sample mass, which implies a negligible
contribution to the IR spectra. The bands detectable in the case of long-chain
amines correspond to amine molecules physisorbed due to strong hydrophobic
interactions of their hydrocarbon chains with SWNT walls. Energetically preferable
adsorption sites are the channels inside SWNTs, according to
molecular-mechanics modeling.
We also attempted
direct solvent-free amination of closed caps of multi-walled carbon nanotubes
(MWNTs) with octadecylamine (ODA), which is essentially similar to amination of
spherical fullerenes. Thermogravimetric analysis revealed a relatively high
content of organics in the product of derivatization (ODA-MWNTs), suggesting
that a large ODA fraction is
distributed over MWNT sidewalls through chemical attachment. This was confirmed by
high-resolution transmission electron microscopy observations. Quantum chemical
calculations showed that the presence of pyracylene units in the closed caps is
not crucial for the amine addition, although site-specificity of the reaction
does depend on the mutual position of five-membered rings. If the caps contain
pyracylene units, the addition preferentially takes place on their 6,6 bonds;
if they do not, the preferential reaction sites are C—C bonds of the pentagons.
While ideal nanotube sidewalls composed of solely benzene rings were found to
be inert with respect to amines, the real nanotube sidewalls must contain
numerous reactive five-membered rings as defects. ODA-MWNTs exhibited an
enhanced dispersibility/solubility in propanol. The
solvent-free amination reaction proposed is the most direct link between carbon
nanotube and fullerene chemistry, contrary to all derivatization methods
designed up to now.
Brief
Biography : Professor Vladimir A. Basiuk,
Research Professor, Instituto de Ciencias Nucleares, UNAM, Circuito Exterior, C.U., A. Postal 70-543, 04510 México D.F., México Tel.: (52) 55 56 22 46 74 Fax: (52) 55 56 16 22 33 E-mail: basiuk@nuclecu.unam.mx
Born
Ph. D.: L.V. Pisarzhevsky Institute of Physical Chemistry, Ukrainian Academy of Science, Kiev, Ukraine, November 1986 Areas of expertise: Surface chemistry (silica, alumina, etc.), surface reactions of organic compounds, IR spectroscopy; Chromatography, coupled techniques GC-FTIR-MS, HPLC-MS; Thermal chemistry of amino acids and peptides, pyrolysis; Molecular evolution and origins of Life, interstellar organic chemistry; Supramolecular chemistry, polyazamacrocyclic compounds; Molecular modeling, molecular mechanics, quantum chemistry (semi-empirical, ab initio and DFT); Chemistry of nanomaterials (carbon nanotubes), computational nanoscience. Publications: 108 journal papers
5. Prof A. K Bhowmick, IIT
Anil K. Bhowmick,
Rubber Technology Centre, Indian Institute of Technology, Kharagpur – 721302,
NANOCOMPOSITE RUBBERS
Prof Anil Bhowmick
ABSTRACT
Polymer nanocomposite is a field of extensive research in recent years. This is a class of organic-inorganic hybrid material, where the inorganic component is uniformly distributed in nanometer scale (10-9 m) within the polymer matrix. The inorganic components are mostly clay and silica. Naturally occurring or synthetic clay are first modified into a polymer compatible nanoclay and then dispersed in the matrix by one of the three methods, namely, solution intercalation, in-situ polymerization and melt intercalation. In-situ polymerization technique is not widely used in the case of rubbers, as it is being practiced with plastics. The remaining two techniques are used for rubbery materials. For polymer-silica nanocomposites, the usual preparation method is a sol-gel technique, where the in-situ silica generation is conducted by sequential hydrolysis and condensation of an inorganic precursor of silica like alkoxysilyl compounds. In the present investigation, styrene-butadiene rubber, and nitrile rubber based clay nanocomposites, and acrylic rubber-silica based hybrids have been prepared . Characterization of the nanofillers and their composites has been done. The resultant nanocomposites and hybrids exhibit superior mechanical properties over the conventional composites made from the unmodified clay and the silica at the same filler loading. The thermal properties are also improved. The results are explained with the help of morphology and dispersion.
6 . Prof
Dipankar Chakraborty, Formerly Director, IACS
Study of Metal Non-metal Transition in Nanoparticles and
Nanoshells
D. Chakravorty : Indian Association for
the Cultivation of Science, Kolkata – 700 032.
Abstract
Metal to nonmetal transition has been theoretically predicted for nanoparticles below a critical diameter. This has been studied experimentally by analyzing the optical absorption behaxviour of different metal – silica nanocomposites. Silver and copper – containing silica gels respectively wered prepared by a sol-gel route. Metal nanoparticles were grown within them by subjecting the gels to an electrodeposition treatment. Polystyrene was used as the matrix for optical absorption measurements. Mie scattering theory was used to explain the characteristic absorption maximum. Also, by fitting the experimental data to Mie’s equation conductivity values for different particle diameters were extracted. It was found that below a critical diameter the conductivity had a value less than Mott’s minimum metallic conductivity.
Silver oxide layers were grown on silver nanoparticles in silver – silica nanocomposites by heating the material in the temperature range 478 to 653 K. Optical absorption showed two peaks viz., one around 370 nm and the other in the range 550 to 700 nm. Theory of optical scattering from ultrafine composite particles was used to analyze the data. The analysis indicated that metal cores having diameters less than 3 nm had electrical conductivity less than Mott’s minimum metallic conductivity.
Ag2O particles of diameter ~ 21 nm were synthesized by a chemical route. A few nanometer thick layers of silver were grown on these particles by heating the latter at tempeatures ranging from 500 to 543 K. Similar nanoshells of copper were also grown on chemically synthesized CuO nanoparticles of median diameter 17 nm. Optical absorption characteristics of these core-shell structure were delineated in the temperature range 270 to 340 K by dispersing them in ethyl alcohol. The results were analysed using size dependent dielectric permittivity incorporating a free path effect. The analysis showed the existence of a metal to nonmetal transition in silver and copper nanoshells with a thickness than 2-3 nm. The extracted values of electrical conductivity over the above mentioned temperature range showed a semiconducting behaviour with an activation energy of around 0.04 eV. Direct electrical conductivity measurements on pellets of nanostrucured powders showed resistivity variation at low temperatures with activation energies in satisfactory agreement with those deduced from the optical absorption analysis.
7. Prof
Kamanio Chattopadhyay, IISc,
“Nano Science and Technology: Perspectives from a materials scientist”
Kamanio Chattopadhyay
Abstract
The words like Nanoscience,
Nano technology and the Nanomaterials are often heard in the context of the
future in science and technology. Beyond the hype, there indeed lies exciting
opportunities both for basic sciences and technologies. In fact nature and life
take recourse to nano technologies during evolutionary process In this
presentation we shall discuss some of the issues of scaling down from the
perspective of a materials scientist dealing with the evolution of
microstructure and its relation to properties. We shall choose few examples
chosen primarily from our work on embedded nano particles to high light the
opportunities that may emerge with the scaling down of the microstructure. The
examples include scaling effect on shape, transformation and properties like mechanical
behaviour. superconductivity and magnetic behaviour.
Chairman, Materials Research Centre And Professor, Department of Metallurgy
Indian
8. Prof G M Chow, NUS,
Department of Materials Science, National
Short-range
and long-range orders and phase miscibility of nanostructured magnetic media
films C.J. Sun, Y.Z Zhou and G.M. Chow*
Department of Materials Science, National
University of Singapore, Kent Ridge, Singapore 119260, Republic of Singapore
*
presenting and corresponding author email: mascgm@nus.edu.sg
Abstract
The properties of
nanostructured films may be controlled by factors such as composition,
structure, microstructure, texture and interfaces. The alloying in nanostructured materials may
not necessarily follow the conventional phase diagrams that ignore the effects of surfaces and interfaces.1 The composition of a specific long range
order (LRO) may also differ from the global average composition. The knowledge of
elemental compositions of a textured LRO is essential to understand how to
control the texture-dependent properties of the film. In this talk,
selected examples of some of our work on nanostructured CoCrPt and FePt films
for high density magnetic recording will be discussed.2-6 The long
range order, short range order, composition of textured Bragg peak and grain
boundaries were investigated using high-resolution x-ray scattering, anomalous
x-ray scattering, extended x-ray absorption fine structure and transmission
electron microscopy. The structural
effects on the in-plane and out-of plane magnetic properties are correlated.
The phase miscibility of nanostructures is addressed.
References:
1. Applied Physics Letters,
75:2503 (1999).
2. Applied Physics Letters,
80:1607 (2002).
3. Journal of Applied
Physics, 91:7182 (2002).
4. Journal of Applied
Physics, 93:8725 (2003).
5. Applied Physics Letters,
82:1902 (2003).
6. Journal of Applied
Physics, in press (2004).
Brief Biography : : Prof
Gan-Moog Chow
Department of Materials Science, National University of Singapore, Kent Ridge, Singapore 119260, Republic of Singapore, phone: +(65) 6874 3325 fax: +(65) 6776 3604 email: mascgm@nus.edu.sg web: http://staff.science.nus.edu.sg/~mascgm/gmc.htm
Gan-Moog CHOW
earned his PhD (Materials Science, 1988) and M.S. (Physics, 1985) at the
Currently, he is an Associate Editor of the Journal of Nanoscience and Nanotechnology, and a member of the editorial board of the Journal of Nanoparticle Research, Reviews on Advanced Materials Science, and Materials Physics and Mechanics. He also serves as a member of the advisory board on Advances in Nanoscale Materials and Nanotechnology, and Encyclopedia of Nanotechnology. He is the Chair of the International Relations Committee of the Materials Research Society (USA).
9. Prof Vimal Desai,
Environmental Stability of Nanomaterials : V. Desai
and C. Suryanarayana [UCF]
Prof Vimal Desai, UCF/USA
Environmental
Stability of Nanomaterials
V. Desai and C. Suryanarayana
Devices manufactured from nanomaterials can have significant degradation issues. First, the surface area is larger compared to the nominal area , increasing the electrochemical current and consequently rate of degradation. Second, the dimensions of nanodevices are expected to be small leading to a very low tolerance to corrosion damage. Excessive presence of grain boundary pathways and inhomogeneity is also expected to increase their susceptibility to degradation.
A fundamental study of the stability of nano materials is warranted. Limited initial experiments have resulted in seemingly conflicting results. In this talk, new results will be offered with a scientific explanation of apparently conflicting results.
10. Dr B. N. Dev,
Abstract
We grow epitaxial self-assembled nanostructures on single crystal silicon surfaces by molecular beam epitaxy (MBE). In this bottom-up process the deposited atoms on the surface self-organize to form nanostructures. The growth features for semiconductors and metal deposited on silicon will be discussed. For Ag growth on silicon a unique growth mode has been identified where Ag islands grow in quantized heights involving 2-,4-,6-.. atomic layers. These results were obtained by scanning tunneling microscopy (STM) measurements. Single-electron tunneling phenomena, as observed by variable temperature scanning tunneling spectroscopy (STS) measurements on these nanostructures, will be discussed. STM/STS measurements are carried out under ultrahigh vacuum conditions with in-situ sample transfer from the MBE growth chamber to the STM/STS chamber.
Brief biography : Dr B.N. Dev
Dr. Dev obtained
his Ph.D. degree in physics (surface physics) in 1985 from the State University
of New York at
11. Prof Roman Dubrovsky,
Surface Engineering Laboratory; New Jersey
Institute of Technology,
Tel. (973) 596-3337; e-mail: dubrovsky@adm.njit.edu
"Synthesis Of Nanocarbon Allotropes with Gas
Outflow" Prof. Roman Dubrovsky, Dr.
V. Bezmelnitsyn
Abstract :
Synthesis of Nanocarbon Allotropes with Gas Outflow.
R. Dubrovsky, V. Bezmelnitsyn
Surface Engineering
Laboratory, Mechanical Engineering Department, New Jersey Institute of
Technology,
We suggest a novel approach for nanocarbon allotropes synthesis. This approach utilizing arc discharge plasma allows to produce controllable amount of high quality carbon vapor used for production of nanocarbon allotropes at above atmosphere pressure under influence of a buffer inert gas flow supplied into hot plasma between two graphite electrodes. Produced carbon vapor is evacuated from the hot plasma zone by efficiently organized radial exhaust stream of an inert gas. The influence of buffer gas outflow, current and electrode diameter on the fullerenes productivity and yield were investigated. As a results of this research, fullerene yield constant value at maximum fullerene productivity produced by used electrodes has been established. Carbon vapor concentration at the exit of carbon vapor from the hot plasma zone (in the gap between two electrode), specific anode vaporization rates and process efficiency have been defined. Furthermore, the fullerene productivity was found to be proportional to electrode cross sectional area at the critical evaporation temperature. In addition, we have demonstrated a possibility to produce carbon nanotubes by the suggested method using Ni-Cr and Ni-Y catalysts. The produced fullerenes were analyzed by HPLC-UV technique. Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HRTEM) and TGA method were used to analyze nanotubes. Obtained experimental results allow significant increase of fullerenes and nanotubes productivity. Also, proposed approach is scalable and capable to produce fullerenes and nanotubes in bulk.
Brief Biography : : Professor Roman
Dubrovsky
Director
of Surface Engineering Research Laboratory.
New Jersey Institute of Technology,
Area of expertise: Surface Modification, Experimental Plasma Physics, Physical Metallurgy, Nanotechnology, Wear Resistance.
1972, PhD Degree from
Since
1983, Prof. in Mechanical Engineering Department, NJIT,
12. Dr
Naba Kumar Dutta, U South Australia, Ian Wark Research Institute,
“Phase separated nanomaterials based on Block Copolymers:
Design, control and characterization”.
13. Prof Feresteh Ebrahimi, U
Tensile Ductility and
Fracture Behavior of Nanocrystalline FCC Metals
Fereshteh Ebrahimi, Materials Science and Engineering
Department University of Florida,
Tensile Ductility and Fracture Behavior of Nanocrystalline FCC Metals
Abstract
It is well established that the strength of nanocrystalline (nc) face centered cubic (FCC) metals increases with decreasing the grain size. However, most of the strength evaluations are conducted in compression (hardness or compression tests). The limited experimental results indicate that nc FCC metals exhibit small or no plastic tensile elongation before fracture.
We have been
successful in fabricating FCC (face centered cubic) nanocrystalline metals and
alloys with grain sizes in the range of 120nm to 9nm via electrodeposition
techniques. Detailed tensile data and fractographic analyses were conducted to
understand the causes of brittleness in nc FCC metals fabricated by
electrodeposition techniques. The results of these studies indicate that nc FCC
metals are inherently ductile and in defect-free tensile samples plastic instability
precedes fracture. The fracture mechanism at very small grain sizes
(approximately less than 20nm) was found to be stress-controlled and dependent
on the stress state. In this paper the tensile properties of nc FCC metals are
discussed in terms of strain hardening and relaxation mechanisms.
Brief Biography : Professor
Fereshteh Ebrahimi
Dr. Ebrahimi
received PhD in Materials Science from Colorado School of Mines, US, in 1982.
After a year of postdoctoral work, she was employed at the Fracture and
Deformation division of NBS (presently NIST). In 1984, Dr. Ebrahimi joined the
Materials Science and Engineering Department at the
14. Prof Perena Gouma, SUNY StonyBrook, USA, Department of Materials Science and Engineering 314 Old
Engineering Building, SUNY at Stony Brook Stony Brook, NY 11794-2275 Phone:
Office: (631) 632 4537; Lab. : (631) 632 8497 Fax: (631) 632 8052 Email:pgouma@notes.cc.sunysb.edu
Nanostructured Materials for Sensors
A.K. Prasad, K. M. Sawicka, and P. I. Gouma Dept. of
Materials Science & Engineering,
State University of New York, Stony Brook, NY 11794-2275
Email:pgouma@notes.cc.sunysb.edu
Abstarct
Our group has been involved with the synthesis and characterization of nanostructured metal oxides of the MoO3 and WO3 systems, organic-inorganic nanocomposites of polymer-biological systems (e.g. PVP-urease) and a combination of both for use in gas detection devices. This paper describes the synthesis techniques used to fabricate nanoparticles, nanowires, nanofibers and non-woven mats of these materials, which are based on sol-gel processing and electrospinnning. Structural and chemical analyses of the nanostructures obtained have been carried out by means of SEM, TEM, AFM, DSC techniques and the thermal stability of the novel materials has been evaluated. Sensing tests using single elements and arrays of gas-sensitive probes in microfabricated substrates have been performed to assess the specificity and sensitivity of the nanostructured materials to gases of interest to environmental and medical applications. The idea of a selective electronic nose is introduced and its potential is demonstrated in the work presented in this paper.
Brief Biography :: Prof Pelagia-Irene (Perena) Gouma, Ph.D.
Assistant Professor Department of Materials Science and Engineering, 314 Old Engineering Building, SUNY at Stony Brook, Stony Brook, NY 11794-2275
Phone: Office: (631) 632 4537; Lab. : (631) 632 8497, Fax: (631) 632 8052
Email:pgouma@notes.cc.sunysb.edu
Dr.
Pelagia-Irene (Perena) Gouma received her PhD degree from the University of
Birmingham, UK in 1996. She holds a MS degree in Engineering Materials, and a
MPhil in Organization Management from the University of Liverpool, UK, and a BS
in Applied Physics from the Aristotelio University of Thessaloniki, Greece. Dr.
Gouma has been an Assistant Professor at State University of New York at Stony
Brook since 2000. Her previous appointment was with the Center for Industrial
Sensors and Measurements at the
15. Prof S P Gubin,
Nanoparticles at the Nanosupport Surfaces : S.P.Gubin,
M.S. Korobov
N.S. Kurnakov
Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
Nanoparticles
at the Nanosupport Surfaces
S.P.Gubin, M.S. Korobov
N.S. Kurnakov Institute of
General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31,
Moscow, 119991 Russia
Over the past few years, in the context of the
nanoparticle engineering the considerable attention has been devoted to nanoparticles
supported on surfaces of different nanocapsules: TiO2, SiO2
spheres, carbon capsules, nanotubes and nanodiamond. As a rule the strong
interaction between a support and these particles takes place, which makes them
stable against coalescence.
This approach
has been generally applied to nanocapsules larger than 100 nm in diameter,
which have a significant chemical affinity to the nanoparticles. The deposition
on nanogranules is very promising for the optimization of physical and chemical
(incl. catalytic) characteristics of nanomaterials. Such materials are inverse
core-shell systems (“core” – nanosupport, “shell” – nanoparticles).
In our work the nanogranules of the
polytetrafluoroethylene (NGPTFE) and SiO2 spheres (opal) were used
for the stabilization of metallcontaining nanoparticles (MCNP).
We developed
the universal method of making well-defined inverse polymer/MCNP core-shell
systems using the thermal decomposition of metallcontaining compounds (MCC) on
the surface of NGPTFE. For the generation of MCNP we used MCC with general
formula MRn (M = Co, Fe, Cu, Ni, Pd, Cd; R = CO, HCOO, CH3COO)
and obtained nanoparticles of metals, oxides, chlorides, sulfides and
selenides. This method has the possibilities also for metallization of SiO2
spheres. TEM has been used to characterize both NGPTFE and MCNP and its result
indicates the size nanoparticles is in the range 2-10 nm with narrow distribution in
the sizes. We have also carried
out a detailed analysis on the composition of nanoparticles. The core-shell
structure based on NGPTFE and on SiO2 is proved by EXAFS, Mössbauer
and X-ray emission spectra.In the report unique magnetic and spectral
properties and also catalytic activity of the obtained nanomaterials will be
discussed. This work was supported by Russian Foundation for Basic Research
(project nos. 02-03-32435, 04-03-32090, 04-03-32311, 04-03-32597), ISTC
(project no. 1991), Russian Academy of Sciences program “Critical Issues in the
Physics and Chemistry of Nanoscale System and Nanomaterials”.
16. Prof Mikhail Gutkin,
GRAIN
BOUNDARY SOURCES OF DISLOCATION ACTIVITY IN NANOCRYSTALLINE MATERIALS :S.V. Bobylev, M.Yu. Gutkin, I.A. Ovid'ko and N.V.
Skiba: Institute of Problems of
Mechanical Engineering, Russian Academy of Sciences, Bolshoj 61, Vas.Ostrov,
St.Petersburg 199178, Russia; E-mail: gutkin@def.ipme.ru
GRAIN BOUNDARY SOURCES OF DISLOCATION ACTIVITY IN NANOCRYSTALLINE MATERIALS
S.V. Bobylev, M.Yu. Gutkin, I.A. Ovid'ko and N.V. Skiba
Abstract
Theoretical models are suggested which describe
transformations of grain boundaries (GBs) and GB sources of lattice
dislocations in nanocrystalline materials under plastic deformation. We
consider such transformations as decay of low-angle GBs, bowing of high-angle
GBs, and emission of partial and perfect lattice dislocations by GBs.
The first two phenomena are studied in the framework
2D dislocation dynamics. Lattice dislocations that form a low-angle tilt boundary
glide under the action of the forces owing to external (applied) and internal
stresses. The balance of the forces causes the critical shear stress at which
the low-angle boundary decays. Such decay processes result in the formation of
high-density ensembles of mobile lattice dislocations that are capable of
inducing plastic flow localization (shear banding) in mechanically loaded
nanocrystalline materials. High-angle GBs are modeled as those containing GB
dislocations with small Burgers vectors. The GB dislocation movement under an
external shear stress gives rise to bowing of high-angle GBs. In certain ranges
of parameters, GB dislocations undergo splitting transformations followed by
emission of partial dislocations from high-angle GBs into adjacent grain
interiors. Emission of lattice partial and perfect dislocations from a GB
disclination, which is a part of a dipole of wedge GB disclinations, is
considered within a 2D energetic approach. It is shown that the critical stress
of the dislocation generation crucially depends on both the size (grain size)
and orientation (angle between the dipole arm and gliding plane) factors. In
relatively coarse-grain materials, the generation of perfect lattice
dislocations dominates over the generation of partial lattice dislocations.
However, when the grain size decreases, the generation of partial lattice
dislocations begins to dominate over the generation of perfect lattice
dislocations.
We also consider a
number of 3D energy-based models describing heterogeneous generation of gliding
dislocation loops at the pre-existing gliding loops of GB or lattice
dislocations. It is demonstrated that depending on the grain size, different
types of dislocation loops must be most effective in generating new loops. When
the grain size is in the range from 50 nm to 100 nm, the most effective sources
are the loops of perfect lattice dislocations. In the interval from 10 nm to 50
nm these are the loops of partial lattice dislocations, and from 3 nm to 10 nm
these are the loops of GB dislocations.
Brief Biography : Prof
Mikhail Yu. Gutkin,
PhD (1990), Dr.Sci (1998). Graduated from the
St.Petersburg State Technical University (MS, 1985). Post-graduate at the Ioffe
Physico-Technical Institute,
Russian Academy of Sciences (1986-1990). Experience: Engineer, Junior Researcher, Researcher – Leader
of research group (1985-1991) at the Central Research Institute of Materials
(St.Petersburg). Researcher, Senior Researcher, Leading Researcher (1991-to
date) at the Institute of Problems of Mechanical Engineering, Russian Academy
of Sciences (St.Petersburg). Visiting
appointments in
17. Prof Mark Hoffman & Dr Xie,
UNSW
Deformation Mechanisms of Nanostructured Thin Films :
Mark Hoffman,
Deformation Mechanisms of Nanostructured Thin Films
Mark
Hoffman
Abstract
Many of the unique mechanical
properties of nanostructured materials arise from their extremely small
microstructural size. This feature is exploited in the development of thin
films which are coated onto ductile substrates to enhance surface hardness and
hence abrasion resistance. The critical issue in ascertaining an understanding
of the unique properties of nanostructured films is therefore an understanding
of their deformation mechanisms.
In this work, nanoindentation is
undertaken to deform thin films including TiN, TiN multilayers and TiSiNx
nanocomposites. The indented region is then studied using scanning and
transmission microscopy of cross-section profiles, prepared with a focussed ion
beam mill (FIB). These observations reveal unique relationships between
microstructure and film properties whereby deformation processes are clearly
explained by models which differ from those traditionally applied to isotropic
material structures.
18. Prof MAXIM
Ivanov, URAS, Russia Institute of Electrophysics, Ural Division of
Russian Academy of Sciences 106, Amundsena st., 620016 Ekaterinburg,
Russia Corresponding author M.G. Ivanov, e-mail: max@iep.uran.ru
The method of laser synthesis of oxide nanomaterials : V.V. Osipov, Yu.A.
Kotov, M.G. Ivanov, V.V. Platonov, O.M. Samatov
List of keywords:
nanopowders, laser-assisted evaporation
Abstract
Recent technologies of
synthesizing bulk nanostructured materials with improved mechanical and novel electromagnetic
and optical properties have generated interest in producing nanopowders of
high-purity and narrow grain size distribution.
Nanoparticles can be produced by a variety of methods
but only a few methods enable to produce the fine nanopowders. One of them
consists in material evaporation and subsequent vapor condensation has been
known for a long time. Laser-assisted evaporation has not found wide
recognition for this purpose because of a low output and high-energy
consumption of related techniques. Its competitiveness with other approaches
has been proved only recently [1,2].
This report deals with the production technology and characteristics of Y2O3 – stabilized ZrO2 (YSZ), Al2O3+YSZ, CeGdO and Nd:YAG nanopowders prepared by evaporation of the materials under irradiation from an original pulse-periodic CO2 laser. The CO2 laser excited by a pulse-periodic combined discharge has been described in detail in [2]. The laser has the following characteristics:
Mean radiation power 800 W
Peak radiation power 10 kW
Radiation pulse length 180-250 ms
Pulse repetition frequency 400-450 Hz
Efficiency 10%
Power consumption 8 kW
For YSZ and Al2O3+YSZ, the output rate was 15-20 g/h, for CeGdO ~ 50-60 g/hour, the energy consumption 30-40 (W*h)/g and 10-15 (W*h)/g, respectively.
The evaporation of materials using the CO2 laser was proved to be an efficient method for production of weakly agglomerated nanopowders of complex compounds with particles having the characteristic size of ~10 nm and a narrow size distribution. An analysis of the obtained results showed that the main factor, which determines the productivity of the installation having certain characteristics, is the specific energy required for evaporation of the material. It is astonishing that the increased output does not give rise to grain size. To explain the fact we investigated the behavior of plasma jet, which was produced by CO2-laser long-pulse irradiation of the materials. For the materials the plasma jet was observed to behave differently. In most cases the glowing part of the jet took the form of a needle, which remain invariable during the effluence. In special situations the glowing part of the jet took the form of a mushroom, which changed during the effluence. The behavior of the plasma jet is believed to be stimulated by Richtmaer-Meshkov instability of the plasma-air border and formation of nanoparticles within the jet.
Dr. M. Ivanov thanks the Russian Science Support Foundation and the Ural
Department of RAS for financial support.
- Muller E., Oestreich Ch., Popp U. et al. Proc. of Fourth Evro Ceramic Conf. (October 2-6, 1995), v.1, pp.219-224.
- Osipov V.V., Kotov Yu.A., Ivanov M.G. et al. Izv. AN, Ser. Fiz., 1999, v.63, No.10, pp.1968-1971.
19.
Prof Ranganathan Kumar,
Nanofluids.
20. Prof S K Malhotra, IIT
Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process
S.K.Malhotra, Paramanand Singh* and A.
Thirunavukkarasu
Composites Technology Centre, IIT, Madras,
Chennai – 600 036, India
*Dept. of Metallurgical & Materials
Engineering, IIT, Madras, Chennai – 600 036, India.
Abstract
A
material having two or more distinct constituent materials or phases such that
the integrated material has properties noticeably different from constituents is
a composite material. Nanocomposites have atleast one of the phases with
dimensions in the nanometer range. They can be classified based on composition
as metal based, ceramic based and polymer based. Based on microstructure,
Niihara classified nanocomposites as : intragranular, intergranular, hybrid and
nano/nano composites. Intragranular has a nanosized phase inside the grain of
the larger phase. In intergranular, the nanophase is in the grain boundary of
the larger size phase. In hybrid, the nanophase occurs both inside the grain
and in the grain boundary. Nano/Nano composites have both phases of nanosize
dimensions. A similiar microstructure classification based on connectivity
concept (by Newnham) describes nanocomposites as 0-3, 1-3, 2-2 etc., where the
first digit denotes dimensionality of second phase and the later of the matrix
(e.g. 2-2 means an interpenetrating two-dimensional microstructure). Making
nanocomposites involves the control of diffusion through process variables such
that nuclei form but their coarsening and growth are suppressed.
Nanopowders
of composite alumina zirconia were synthesized by the sol gel process. The
precursors used were aluminium secondary butoxide and zirconium isopropoxide.
These organometallic precursors were chosen for their very high purity. An
earlier process used for microscopic alumina-zirconia ceramic composites was
extended to nanopowder synthesis. Critical modification enabled the synthesis
of nanopowder. Further, it was realized that a number of variables influence
sol gel synthesis. In addition, extended studies were carried out to
qualitatively study the nature of the sol gel process. A good understanding of
different parameters that affect the sol gel process and the nature of their
influence was obtained.
Brunauer,
Emmett and Teller (BET) was applied to estimate surface area per unit weight of
sol gel powder. The very high surface area showed fully nanosize nature of
powder. The powders had unprecedented fine nanosize. Transmission electron
microscopy (TEM) showed nanopowder and provided an estimate of nanopowder
particle size. Diffuse reflectance spectroscopy (DRS) in the UV-visible - near
IR was also used to analyse nanosize. In addition qualitative optical
absorption was used to obtain a maximum particle size of the nanopowder. All
the methods led to fully consistent estimate of particle size.
Extensive studies have been carried
out by varying different parameters that affected the particle size. These
included the solvent, precursor concentration, water dilution, temperature, pH
and water to alkoxide ratio. The results led to variations in the particle size
depending on the variation of experimental parameters. Artificial neural
networks (ANN) were used to analyse the effect of each parameter.
ANN is a method of artificial
intelligence which uses an interconnected network of `neurons' - an artificial
equivalent of biological neurons in human brain. The input data of a few
experiments was entered into the network. The network attaches weights to each
variable and passes it onto the other neurons in the network. These then use
the output from the earlier neuron(s) as input and re-weighs each factor, this
process is continued across the network. In back propagation method ANN used in
this study, the result circulate back into the first neuron and the process is
repeated. By changing the connection weights (training) the network learns the
solution to the nature of the variables in the sol gel process. The strength of
connection between neurons is stored as the weight value for the particular
connection between two or more neurons. The ANN was `trained' for a few sol gel
experiments and validated with a few more experiments already conducted. Then
it was used to predict the particle size for hypothetical experiments
formulated by varying the factors. It showed which was more important factor
and which was less important and for what combination of experimental factors.
Following the synthesis,
characterization and analysis of nanopowders, development of bulk materials was
taken up.
The composite nanopowders from the
sol gel process were used to fabricate bulk nanocomposites with both alumina
and zirconia having sizes in the nanometer range. The fabrication involved time
- temperature studies wherein the temperature of sintering and time at
temperature were varied. This led to phase separation and crystallisation of
the amorphous powders that were composite. The XRD of the fabricated material
showed that the process was optimal when there was a balance between
temperature of sintering and time period for which sintering was carried.
However the process had deviations from conventional sintering and had a habit
plane for grain/phase growth.
The fabricated bulk nanomaterials
are expected to have far higher properties as compared to their microscopic
counterparts. Hence, the elastic modulus, hardness and fracture toughness were
determined using an indentation hardness tester. The results showed very high
properties which were consistent when the calculations were made using
different relations reported in the literature. The extraordinary properties
are even more significant when the fact that the material had high porosity is
considered.
Thus a ceramic nanocomposite with
novel properties was realised with possibility for further improvement in
properties.
The
novel process, materials, properties, analysis and characterization have been
realised in these studies through a series of critical innovations and yet
present a scope for further improvement.
21. Professor I Manna, IIT Kharagpur, India Metallurgical & Materials Eng Dep., Indian Institute of
Technology, Kharagpur 721 302, India
A.
Development of Al-based Ternary
Amorphous/Nanocrystalline Alloys by Mechanical Alloying
Indranil MANNA
Abstract
Development of high specific strength-structural material is of significant interest to the transportation and aviation industry. The strength of crystalline and age hardenable aluminum alloys is limited a maximum of about 600 MPa. However, recent studies claim that the compressive strength of Al-alloys could reach over 1200 MPa in amorphous or nanocrystal dispersed amorphous condition. Recently, we have been successful in developing a number of Al-based ternary Al-Cu-TM or Al-TM-Si amorphous alloys with suitable addition of transition metals (TM) by mechanical alloying [1-5]. In this paper, the genesis of complete/partial solid-state amorphization of these alloys by high-energy planetary ball milling will be presented on behalf of the team of investigators and collaborators involved in this project.
Dispersion of nano-intermetallic phases in amorphous matrix may be achieved either by continued milling or by subsequent controlled annealing. The identity and sequence of phase evolution have been monitored by x-ray diffraction, high-resolution transmission electron microscopy and differential scanning calorimetry. The microstructural evolution during mechanical alloying follows a complex and interdependent sequence of grain refinement, mutual dissolution (alloying), nanocrystallization and/or amorphization. The genesis of solid-state amorphization or nanocrystallization has been investigated by positron annihilation spectroscopy (PAS) and nuclear magnetic resonance (NMR). Thermodynamic calculations based on modified-Miedema approach allow determination of appropriate composition range for complete/partial amorphization. Both kinetic and thermodynamic factors play a significant role in determining the final microstructure comprising nano-intermetallic and amorphous phases. Thus, it appears that the present approach may be useful in developing high specific strength Al-based amorphous and nano-intermetallic dispersed amorphous matrix composites by the inexpensive and versatile processing route of mechanical alloying.
- Materials
Letter 58 (2003) 403 – 407.
- Zeitschrift
für Metallkunde 94 (2003) 835 – 841.
- Mater.
Sci. Engg. A 359 (2003) 11 – 17.
- Materials
Physics and Mechanics 4 (2001) 116 – 120.
- Scripta
Mater. 45 (2001) 1191-1196.
B.
Nanocrystalline Metal-hydrides for Compressor Driven Reversible Heating-cooling Applications
S.
Bera,1 E. Prasad,1 M. Ramgopal2,
1Metallurgical and Materials Engineering Department,
2Mechanical Engineering Department,
Key words: Mechanical alloying, metal hydride, nanocrystals, thermal conductivity, hydrogen absorption/desorption
Abstract
Stringent restriction on the use of CFC for vapor compression based refrigeration systems to counter ozone depletion and global warming led to a serious initiative in developing an alternate technology for refrigeration and similar low temperature applications. Compressor driven metal-hydrogen system with hydrogen as the working fluid alternated between metal-hydride containing tanks absorbing and desorbing hydrogen to produce exothermic/heating and endothermic/cooling effects respectively, offers an environmental friendly and energy efficient system for close-circuit heating and cooling applications. In this regard, titanium and zirconium are two potential candidates with unique combination of low enthalpy and hysteresis of hydride formation and dissociation. Nanocrystalline powders (< 20 nm) with a large intercrystalline volume fraction may significantly enhance the kinetics/efficiency of this reversible reaction. However, thermal conductivity of a powder mass is usually poor and hence poses a problem in heat transfer from a powder bed. Thus, the present study is devoted to synthesizing nanocrystalline AB2 type (Ti,Zr)(Fe,Cr)2 quaternary alloys, characterizing their microstructure and assessing thermal conductivity of the powder compacts with or without graphite addition.
Elemental Ti, Zr, Fe and Cr were taken in appropriate proportions and subjected to mechanical alloying in a high-energy planetary ball mill in wet (toluene) medium with ball to powder weight ratio of 10:1. Altogether eight alloys were synthesized and characterized. The identity and sequence of phase evolution in different stages of mechanical alloying and compaction/sintering were studied by x-ray diffraction (XRD) analysis. Average grain size was determined from broadening of the most intense peak of the concerned phases using appropriate method and correction. The results of the XRD analysis concerning grain size and phase evolution were verified by transmission electron microscopy (TEM) using both high-resolution bright field images and selected area diffraction (SAD) analysis, respectively. Enthalpy of hydrite formation was determined using model based thermodynamic calculations. Thermal conductivity of cold and warm compacts was measured using a transient technique involving heat dissipation through the compact by placing a heated copper block on its top.
In the talk, a detailed analysis of the results on microstructural evolution, thermodynamic calculations and thermal conductivity will be presented.
C.
Synthesis
and Characterization of Nanofluid for Advanced Heat Transfer Applications : M.
Chopkar1, S. Kumar1, P. K. Das2 and I. Manna1*
1Metallurgical
and Materials Engineering Department, Indian Institute of Technology, and 2Mechanical Engineering
Department, Kharagpur, W.B. 721 302, India
Abstract
Heat dissipation from machines, devices and reactors
is usually carried out by a common fluid like water, ethanol or ethylene-glycol
if the source and sink are separated by considerable distance. It is well known
that solids have significantly greater thermal conductivity than that of a
liquid or gas. Hence, dispersion of solid particles enhances thermal
conductivity of a given fluid unless sedimentation, agglomeration, clogging and
similar problems offset the derived benefits. Recently, a new class of heat
transfer fluid, or nanofluid, has been developed that comprises low volume
fraction of very fine particles in a given fluid to form a stable colloid and
offers a significantly higher thermal conductivity. In the past, dispersion of
low volume fraction of ceramic (Al2O3, Cu2O)
and metallic (Cu) particles in conventional fluids like water and ethylene
glycol was reported to yield excellent improvement in thermal conductivity.
However, the mechanism and effect of process parameter were not studied at
length.
In the present study, a systematic effort made to
synthesise and characterize Al rich Al-Cu and Al-Ag binary alloy powders
prepared by mechanical alloying, disperse the powder in water and ethylene
glycol in very low volume fraction and carry out suitable measurements of
thermal properties of the nanofluid. The
milled powder was characterised by XRD (phase analysis, grain size
determination), DLS (determination of particle size and distribution) and EDS
(compositional analysis). Thermal conductivity of the base fluid and nanofluid
was measured using an indigenously developed thermal comparator set up. The
measurements were calibrated using standard heat transfer fluid.
An
analytical study on the influence of shape factor (major to minor axis ratio)
of non-spherical solid particles on effective thermal conductivity of nanofluid
was also carried out. The results indicate that the aspect ratio of oblate
spheroid particles significantly influence the thermal conductivity of
nanofluid, under the comparable condition.
The overall
results appear quite promising for development of nanofluid for advance thermal
engineering applications like automobile, sports vehicles, satellite, heat
transfer baths, and VLSI/microelectronics devices.
22. Professor B.S. Murty, Dept. of Metallurgical and
Materials Eng, Indian Institute of Technology, Madras, Chennai 600 036,
Nano Ferroelectrics and Phase Transformations in
Nanocrystalline Materials Synthesized by Mechanical Alloying
B. S. Murty*, Jatin Bhatt, S. K. S.
Parashar, R. N. P. Choudhary and S. K. Pabi
Department of Metallurgical and Materials
Engineering, *IIT
Indian Institute of Technology,
Kharagpur 721302, India
Mechanical alloying (MA)/mechanical milling (MM), a high energy ball milling process, has been established as a viable solid state processing route for the synthesis of nano materials. Nanocrystalline alloys, nano intermetallics, nano ferroelectrics and nanocomposites have been synthesized in a number of systems by MA. The phase fields in all the above systems are decided by the crystallite size of the nanocrystalline phases. Nanocrystalline PZT with Nd, Gd and Zn doping has been successfully synthesized by MA. The dielectric constant of the nanocrystalline PZT prepared by MA is the highest reported so far (34,000) by any ferroelectric material. The structural phase transitions in the PZT in the nanocrystalline state will be discussed.
Work
on a number of systems such as Cu-Ni, Cu-Zn,
Brief
Biography of Prof B.S. Murty
Prof. B.S. Murty
joined Indian Institute of Technology
23. Prof S K Pabi, IIT
CATALYTIC CHARACTERISTICS OF
MECHANICALLY ALLOYED NANOCRYSTALLINE NICKEL ALUMINIDES IN H2O2
DECOMPOSITION by P. K. Deya,
M. Dutta Guptab and S. K. Pabia aMetallurgical and Materials
Engineering Department, and bDepartment of Chemistry, Indian
Institute of Technology, Kharagpur, 721302, India.
CATALYTIC CHARACTERISTICS OF MECHANICALLY
ALLOYED NANOCRYSTALLINE NICKEL ALUMINIDES IN H2O2
DECOMPOSITION
P. K. Deya,
M. Dutta Guptab and S. K. Pabia
aMetallurgical and Materials
Engineering Department, and bDepartment of Chemistry, Indian
Institute of Technology, Kharagpur, 721302,
EXTENDED ABSTRACT
The mechanical alloying route for the production of catalyst is very attractive because of its flexibility, inherent good intermixing, low capital cost, good production rate and ease of scaling up; although, contamination from the milling media may pose a problem in some cases. The influence of defect structures on the catalysis can be conveniently studied using the mechanically alloyed phases in Ni-Al system. In particular, the NiAl phase can exist as a single phase partially ordered B2-intermetallic compound over a wide composition range of 30 to 65 at. % Ni in the mechanically alloyed state, as against the equilibrium composition of 45 to 59 at. % Ni. It is known that NiAl phase cannot be disordered even by rapid solidification, and it can be only partially ordered in the mechanically alloyed state. Interestingly, Cr addition tends to disorder mechanically alloyed NiAl phase and therefore, influence of this disordered structure on the catalytic activity is also investigated in the present work. Besides, a simple method of pretreatment for increasing the activity of some Ni-Al phase is also reported. The model reaction chosen for this catalytic study was the decomposition of H2O2, and the results were explained on the basis of geometric and electronic theories, and the microstructural characteristics of the nanocatalysts.
It was found that liquid phase catalytic decomposition of H2O2 was marginally effected by the microcrystalline pre-alloyed-Ni30Al70 powder (particle size £45 mm) containing NiAl, Al3Ni2 and Al3Ni phases. High-energy ball milling of this pre-alloyed-Ni30Al70 generated nano-sized (~12 nm) NiAl particles, which manifested a remarkable catalytic activity, similar to that of the NiAl phase of Ni30Al70 composition synthesized by mechanical alloying of an elemental blend. The appearance of the disordered Ni3Al (or solid solution of Al in Ni) in Ni68Al32 diminished the activation energy appreciably as compared to that for nanostructured NiAl phase of Ni65Al35 composition; although, the catalytic yield of both the catalysts were similar.
The x-ray photoelectron spectroscopy (XPS) indicated that in binary Ni-Al nanophases, Ni present as alloyed-Ni was possibly responsible for the catalytic activity. The negative shift of the XPS peaks of alloyed-Ni can be attributed to the electron transfer from Al to Ni on the surface, and its magnitude remained almost constant for a particular phase. The magnitude of electron transfer from Al to Ni on the surface in NiAl phase was much higher than that in Al3Ni and disordered Ni3Al phase. Thus, the activity of the nanocrystalline Ni-Al phases seems to depend on the electronic state and the amount of the surface Ni bonded to Al, as well as, the defect structure of the catalyst. The active sites for the H2O2 decomposition on the surface of nanostructured NiAl phase appeared to consist of ~4 nickel atoms. All the catalysts got gradually deactivated with the formation of Al2O3 enriched surface layer possibly by the migration of Al atoms from the interior to the surface.
In NiAl (Cr) system, Cr in the NiAl phase appeared to interact more
with Al than with Ni, and the negative shift of Cr peaks may be due to the electron
transfer from Al to Cr on the surface. The Cr+3 state on the surface
of disordered NiAl (Cr) may be correlated with the observed catalytic activity
in the decomposition reaction of H2O2. Presence of 20 at.
% Cr in the nanostructured NiAl phase remarkably retarded the deactivation of
the catalyst.
The as-milled disordered Ni3Al phase (or solid solution of Al in Ni) had very poor catalytic activity; but it showed profound catalytic activity after a simple pretreatment in H2O2, apparently due to the formation of non-stoichiometric NiO on the surface of the catalyst in course of the pretreatment.
Brief Biography : Prof S K Pabi
Prof. S. K. Pabi joined the
Indian
24. Dr Pradip, TRDDC/TCS,
Modeling of Nanoparticle Synthesis by Population
Balance : Venkataramana
Runkana, P.C. Kapur and Pradip* Tata Research Development and Design Centre,
54-B, Hadapsar Industrial Estate,
Dr Pradip, TCS,
Modeling of Nanoparticle Synthesis by Population Balance
Venkataramana
Runkana, P.C. Kapur and Pradip*
Tata Research Development and Design Centre
54-B, Hadapsar Industrial Estate,
Many commodity chemicals such as carbon black, titania, zinc oxide and silica are produced as nanoparticles in aerosol flame reactors on the industrial scale. This route for synthesis of nanoparticles is characterized by high temperatures and very short reactor residence times. Although the commercial processes have been in existence for quite some time, fundamental principles that govern the production of nanoparticles are not well understood. On the other hand, process optimization and control of aerosol reactors is essential to produce nanoparticles with a narrow size distribution and desired specific surface area and chemical composition. The product characteristics depend critically on inlet reactant concentration and flow rate, shape and nature of the flame, residence time and temperature profiles inside the reactor. Process modeling is a prerequisite for meaningful optimization and control of manufacturing processes. The population balance framework is most appropriate for modeling the process for predicting particle size distribution. In addition, it is necessary to integrate the population balance with a suitable computational fluid dynamics (CFD) model of the reactor in order to incorporate the influence of flame characteristics and fluid flow regime on product characteristics. We present a population balance model that describes the formation of nuclei or primary particles by chemical reaction followed by growth to dimers and higher order aggregates by coagulation and sintering. The irregular structure of aggregates is taken into account by incorporating their fractal dimension. The model is tested with experimental data available in the literature. The effect of some of the process variables on nanoparticle size distribution is simulated. As the simulation of the effect of flame
characteristics and turbulent flow phenomena inside the reactor by coupling population balance with CFD is computationally prohibitive, strategies to reduce the computational burden are discussed.
25. Dr R. Radhakrishnan, USA, Manager-Technology
Development, Materials Modification, Inc. 2721-D Merrilee Drive, Fairfax, VA
22031
703-560-1371 x 14 (Ph),
703-560-1372 (Fax) radha@matmod.com
Magneto-Rheological Fluids Containing Iron
Nanoparticles
R. Radhakrishnan
Materials Modification, Inc.,
Abstract
Magneto-Rheological (MR) fluids are suspensions of magnetic particles in a fluid that exhibit a viscosity change when subjected to a magnetic field. The use of nanocrystalline magnetic particulates provide more stability by significantly reducing the settling rates while maintaining useful stress levels. Nanocrystalline particles of iron measuring 25-30 nm in particle size were synthesized using a proprietary Microwave Plasma Synthesis technique. MR fluids were prepared by suspending these particles in hydraulic oil in varying weight fractions. Hybrid MR Fluids containing both micron and nanocrystalline particles were also prepared. The rheological properties of these fluids were characterized and correlated to the Herschel-Bulkley and Bingham plastic models.
The damping behavior of these fluids was studied using a MR damper. Both hybrid fluids and nanocrystalline iron based fluids were studied. The paper will report on the behavior of the fluids in damping applications. Preliminary results from modeling of the behavior using Genetic Algorithms (GA) is also presented.
Acknowledgement: This work was supported through grant
# DMII 0110447 from the National Science Foundation.
26. Dr Debdatta
Ratna, Naval Mat Research
Naval
POLYMER/CLAY NANOCOMPOSITE
USING EPOXY BASED MATRIX
D. Ratna , B.C. Chakraborty, H. Dutta*, A.K. Banthia* : Naval Materials Research Laboratory,
Abstract
Development polymer /clay nanocomposite (PCN) is one of the latest evolusionary step in material science. PCN
was discovered by researcher at
Brief Biography : Dr Debdatta
Ratna
Dr. D. Ratna was
born in Midnapore,
27. Professor Namita Roy Choudhury, U South
Australia, Ian Wark Research Institute,
Namita Choudhury <Namita.Choudhury@unisa.edu.au>
"Molecularly designed hybrids and
nanomaterials"
Molecularly Designed Nanomaterials
Namita Roy Choudhury
Ian Wark Research Institute
Organic-inorganic hybrids and nanocomposites of all
generations were prepared by three independent methods: generation 1 hybrid by
sol-gel method, generation 2 hybrid by, self assembled filler exfoliation and
generation 3 hybrids from covalently bonded oxometallate nanofiller or surface
modified metal oxide cluster in polymer. Of particular mention is the bottom-up
approach to synthesise hybrid materials in which organic polymers are
efficiently bonded to structurally well-defined oxometallate framework or
cluster. We have demonstrated how precisely the growth of nanoparticle in a
polymer matrix could be controlled through organic template mediated
hybridization. Recently we have also
demonstrated the role of surfactant at and during, development of nanofiller
with different development strategies. Solid state NMR, small angle X ray and
neutron scattering methods enabled us to investigate the structure and dynamics
of those developed materials. AFM and TEM were used to visualise the morphology
of the systems. It is observed that precise control of particle size can be
achieved using polymers of defined architecture.
References:
1. Organic-Inorganic Hybrid from Ionomer, Y. Gao and N. R.
Choudhury, in Handbook of Organic_Inorganic Hybrid Materials and
Nanocomposites, Ed. H. S. Nalwa, American Scientific Publ, USA, pp
271-293, 2003.
2.
Organic-inorganic hybrid from surface-modified oxotitanate cluster.
Choudhury et al Chemistry of Materials, 14(11), (2002) 4522.
3.
Organic-Inorganic Hybrid from Ionomer via sol-gel reaction
Choudhury et al Chemistry of Materials, 13 (2001)
3644.
4. Silicon Nanocomposites: Exploring POSS-ibilities,
Choudhury et al Polymer Preprints, ACS Meeting,
5.Inorganic-Organic Hybrid Polymers by
Polymerisation of Methacrylate Substituted Oxotantalum Clusters with
Methylmethacrylate: Thermomechanical and Morphological Properties, Choudhury et al
International Workshop on Sol-Gel Sci. and Technol, August 2003, Sydney.
6. Template Mediated Hybrid from Dendrimer,
N. Roy Choudhury, International Workshop on Sol-Gel Sci. and Technol, August
2003, Sydney.
8.Hybrid
Organic-Inorganic Nanocoating for the Corrosion Protection of Metal, M.
Oaten and N. Roy Choudhury, Int. Conf. On Corrosion and Prevention–O2, Adelaide
Hilton Adelaide, SA, 10-13 Nov., 2002,
Brief Biography : Brief CV: A/Prof. Namita Roy Choudhury
Namita Roy Choudhury is an Associate Professor at the Ian Wark Research Institute, University of South Australia. Her recent major activities pertain to design and development of nanostructured material for subsequent immobilization onto a polymer, molecular reactions in organized systems, dendrimer and other cage molecules. She obtained her PhD from IIT, Kharagpur and subsequently did her post-doctoral research at CNRS, Mulhouse, France for two and half years. A/Prof. Choudhury’s previous appointment at Royal Melbourne Institute of Technology (1994-1997) involved teaching and research in elastomer engineering and polymeric material design. The author of over 160 publications, including 10 invited book chapters, she is currently leading a number of research projects in the areas of Organic-Inorganic Hybrids and nanocomposites, polymeric coating, antimicrobial surfaces, biomimetic materials and polymer scaffolds. Her research activities have attracted funding over $5M from several funding bodies including Australian Research Council and many industries.
28. Prof Sudipta Seal, UCF, USA Sudipta Seal
(Ph.D.), http://people.cecs.ucf.edu/sseal/ Nano Initiative Coordinator for UCF, OSR, Suite 302 Phone: (407) 882 1119, Fax: 407 882 1156 http://nanotech.research.ucf.edu/
Associate Professor: AMPAC & Mechanical, Materials and Aerospace Engineering
(MMAE), Biomolecluar Science Center (Assoc. Member) Room. 381, UCF, 4000
Central Florida Blvd. Orlando, Florida 32816-2455 sseal@pegasus.cc.ucf.edu,
sseal@mail.ucf.edu Phone: (407) 823 5277 Fax:(407) 823 0208, 882-1462 Surface
Engineering and Nanotechnology Lab (SNF), Phone: (407) 882 1184 Suite 403/404:
12443 Research Parkway, Orlando, Florida 32826
Multifaceted applications of functional nanoparticles
Multifaceted applications of functional nanoparticles
S. Seal
Abstract:
Nanoparticle possesses unique properties such as, increase in lattice parameter, shifting and broadening of Raman allowed peaks, and blue shift in UV absorption spectra, that
makes it more technologically important material than it micron counterpart. However, nanomaterials have a very high tendency to agglomerate due to high surface energy, which is likely to downgrade such wonderful properties of nanoparticles. Therefore, it is very important to synthesize nanocrystalline material with controlled size and without agglomeration.The present study shows the unique capability of Seal's research group to cost effectively produce engineered oxide nanostructures in the range of 2-6 nm. These nanostructures found applications in high temperature oxidation resistant coatings, prolonging of cell life spans, aging, UV blockers, engineered host to study cell dynamics and control release, heat transfer fluids, fuel additives for soot reductions, less NOx emission for pollution free environment, enhanced catalytic properties, better yield in oil and gas lines, highly sensitive room temperature gas sensors and many other attractive and unique properties. Thus the current research in nanostructures will have a profound effect in nanobiotechnology, energy and other high technology materials industries.
Biography :
Prof Sudipta Seal
Ph.D.degree in 1996 U Wisconsin after MS from U Sheffield UK. Undergraduate degree from Indian Institute of Technology (IIT – India) in Metallurgical & Materials Engineering – 1990. worked in the TATA Iron Steel Co (TISCO) sector.
After Ph.D. he joined Advanced Light Source, Lawrence Berkeley National Laboratory, U California, Berkeley as a post doctoral fellow in Materials science and synchrotron radiation X-ray photoelectron spectroscopy of advanced materials. In 1997 fall, he joined the faculty in AMPAC and the Department of Mechanical, Materials, and Aerospace Engineering, UCF and became an Associate Professor in 2002; An adjunct faculty member in Biomolecular Science Department and serving as a nanoinititaitve Coordinator for UCF. Professor Seal ’s work has been recognized through various awards. He is in the editorial board of nanoscience and nanotechnology, Reviews in Advanced Materials, Chair of the Surface Engineering sector for JOM, in the Review Board of Metallurgical Transactions. In the field of nanoscience and materials processing, he has collaborations with university of New South Wales, Sydney, Queensland, Australia, NIMS – Japan, IIT – India, Polish Academy of Sciences – Poland, University of Groningen – Netherlands. Professor Seal has six years of teaching and research experience in the field of nanoscience and nanotechnology and almost ten years in the area of materials processing and surface engineering. His projects are funded by National Science Foundation (NSF), National Institute of Health (NIH), Office of Naval Research (ONR), NASA and many Industries. Dr. Seal has published over 150 research papers, books and book chapters in the area of surface science and engineering and nanotechnology; delivered more than 150 invited lectures and research presentations in USA and abroad and is the recipient of the 2002 ONR Young Investigator Award (ONR-YIP) and Distinguished ASM-IIM lecturer Award from ASM 2003; received the Exemplary Service Award from the TMS Materials Processing and Manufacturing Division as a Surface Engineering Committee chair and received the best student Research Paper Award from Applied Surface Science Division of AVS- 1996. An active member of ASM, TMS, MRS, ECS, and AVS societies.
29. Dr Raman Singh, Monash U, AUSTRALIA, School of Physics and Materials
Engineering, Monash University (Melbourne), Vic 3800,
Corrosion of
Nanocrystalline Metallic Materials
R.K. Singh Raman
Abstract
The last decade
has witnessed a great surge in the materials science and engineering research
on the development of nanocrystalline and sub-microcrystalline materials. A great deal of these studies has focused on
the fundamental characterisation of the structures and their bearing on the physical
and mechanical properties of ultrafine materials. Corrosion behaviour of
nanocrystalline materials has received very limited attention. Rather
simplistic approach to understanding the role of nanostructure in corrosion as
compared to the microcrystalline material of same composition may suggest an
increase in corrosion rate of the nanostructured material due to large fraction
of grain boundaries (i.e., high energy areas). However, the nature of influence
of nanostructure per se on corrosion
does not seem to similar in all cases.
In fact, the nature of influence can be contradictory, depending on the
type of corrosion and environment-material system. For example, nanocrystalline
structure is reported to improve the resistance of an iron aluminide system in
a corrosive gas, whereas the dissolution rate of a nanocrystalline copper is
reported to be greater than the conventional polycrystalline copper.
This paper discusses the relevant fundamentals of a few major forms of corrosion of nanostructured metallic materials.
Brief Biography :
Dr Raman Singh
Qualifications :Ph.D.
(Metallurgical and Materials Engineering), Indian
Institute of Technology (IIT), Kharagpur, India Employment:
Indian Atomic Energy (9 years), University of New South Wales,
Sydney (3 years) Current Position Senior
Research Fellow (Monash University); Experience & Interests Stress Corrosion Cracking of steels, their weldments and light alloys Stress Corrosion Cracking monitoring techniques High
Temperature Gaseous Corrosion of steels and weldments Role of alloy
microstructure on corrosion of steels and light alloys Corrosion of
magnesium alloys Corrosion resistance coatings and paints Supervising/Supervised: 9 PhD and Masters students Publication: over 50 reviewed journal papers and 40 conf papers Govt / Industry Research Funding: over $1million; Nano-interst : in
Corrosin areas
30. Prof C. Suryanarayana,
Environmental Stability of Nanomaterials : V. Desai
and C. Suryanarayana [UCF] : SHARED WITH Prof VIMAL DESAI
31. Prof Sabu
Thomas,
A). POLYMER NANOCOMPOSITES School of Chemical Sciences, Mahatma Gandhi University, Kottayam, Kerala, India - 686 560
POLYMER
NANOCOMPOSITES
Prof. Dr. Sabu Thomas
School of Chemical Sciences, Mahatma Gandhi
University,
Kottayam, Kerala, India - 686 560
Abstract
The field of polymer nanocomposites is
stimulating both fundamental and applied research because these nanoscale
materials often exhibit physical and chemical properties that are dramatically
different form conventional microcomposites. A large number of nano particles,
layers silicates and polymeric whiskers are being used of the preparation of
nano composites. Since the Toyota research group's pioneering work on nylon6/layered
silicate nano composites, polymer nanocomposites containing layered silicates
have attracted much attention. The polymer/layered nanocomposites can exhibit
increased modulus, decreased thermal expansion coefficient, reduced gas
permeability, increased solvent resistance and enhanced ionic conductivity when
compared to the polymer alone. In the proposed talk, the different preparation
techniques for polymer nanocomposites will be discussed. The role of various
surfactants in improving the polymer/filler interaction will be reviewed. The
various characterization techniques for nanocomposites will be addressed. In
the case of semi crystalline polymers the role of crystallization on the
intercalation and exfoliation will be discussed. The important properties of
nanocomposites will also be presented. Finally recent developments in cellulose
nanocomposites and bio-nanocomposites will also be described.
B). Synthesis and
Characterisation of Calcium Phosphate Nanoparticles via Polymer Induced Crystallisation
Selvin Thomas P1*, Sabu Thomas1 & Sri Bandyopadhyay2 1School of Chemical Sciences, Mahatma
Gandhi University, Priyadarshini Hills P.O., Kottayam, Kerala, India – 686560 *Visiting Research Associate, School of
Materials Science and Engineering, University of New South Wales, Sydney-2052,
Australia 2School of Materials Science and Engineering, University
of New South Wales, Sydney-2052, Australia
Synthesis and Characterisation of Calcium Phosphate Nanoparticles via Polymer Induced Crystallisation
Selvin
Thomas P1*, Sabu
Thomas1 &
Sri Bandyopadhyay2
1School
of Chemical Sciences, Mahatma Gandhi University, Priyadarshini Hills P.O.,
Kottayam, Kerala, India – 686560
*Visiting
Research Associate, School of Materials Science and Engineering, University of
New South Wales, Sydney-2052,
2School
of Materials Science and Engineering, University of New South Wales,
Sydney-2052,
Abstract
Aim of this work is to
explore the feasibility of the preparation of the nanoparticles via polymer
induced crystallisation technique. Calcium chloride and polyethylene oxide were
allowed to form a complex in methanol medium. To the reaction medium
stoichiometric
amounts of trisodium
phosphate were added and allowed for digestion for 24 hours. The precipitated
calcium phosphate were washed with distilled water and dried. X-ray Diffraction
and Transmission Electron Microscopy were employed to characterise the
nanoparticles. The obtained nanoparticles were in the size range between 8-20
nm range. The nanoparticles were incorporated in Polystyrene matrix. The
mechanical properties were found to be increasing in very good amount.
C) Dynamic Mechanical and Rheological Behaviour of Natural Rubber
and Synthetic Rubber Latexes and their Blends with Layered Silicates
Ranimol
Stephen and Sabu Thomas, Mahatma Gandhi University, India
Dynamic Mechanical and Rheological Behaviour of
Natural Rubber and Synthetic Rubber Latexes and their Blends with Layered
Silicates
Ranimol Stephen and Sabu Thomas
School of Chemical Sciences, Mahatma Gandhi University, Kottayam, Kerala- 686 560, India, E- mail: sabut@sancharnet.in, sabut552001@yahoo.com
Abstract
Nowadays, polymer layered silicates nanocomposites have been extensively studied in industry and in academic level due to its enhanced properties such as mechanical strength, thermal resistance, high gas barrier properties etc. The important characteristics of layered silicates are its ability to disperse into individual layers and also its reactions with organic and inorganic cations. The present study deals with the dynamic mechanical and rheological behaviour of natural rubber (NR), carboxylated styrene butadiene rubber (XSBR) and natural rubber (NR)/ carboxylated styrene butadiene rubber (XSBR) latex blends. The layered silicates such as Na- Bentonite and fluorohectorite were used for the studies. The dynamic mechanical properties of polymer layered silicate nanocomposites depend highly on the extent of intercalation and exfoliation. It can be observed that the stiffness increased for latex with layered silicates. The glass transition temperature shift occurred with weight percentage of layeres silicates. The increase in storage modulus compared with pristine polymer is an indication of exfoliated system. The rheological behaviour of these latexes with varying amount of layered silicates was studied. The viscosity of the systems increases with weight percentage of layered silicates.
Brief Biography: Prof. Sabu Thomas
PROFESSOR, SCHOOL OF CHEMICAL SCIENCES, MAHATMA GANDHI UNIVERSITY, PRIYADARSHINI HILLS P. O, KOTTAYAM, KERALA, INDIA- 686 560, Fax: 91-481-2561190 Tel: 91 - 481 – 2730003 email: sabut@sancharnet.in
Born march
14, 1960, in Kottayam, India; Nationality:
Indian.
Education: B. Tech., Polymer Science and Technology (1983), Cochin University of Science and Technology, Cochin, India, Ph.D in Polymer Science and Engineering (1987), Indian Institute of Technology, Kharagpur, India.
Areas of expertise: Polymer Blends, Fibre Filled Polymer composites, Particulate Filled Polymer composites, Diffusion, Transport and Pervaporation Phenomena, Interpenetrating Polymer Systems, Recyclability and Reuse of Waste Plastics and rubbers, nanocomposites
Honours/Awards: - Visiting Professor in Lab. of
Macromole. Structure Chemistry, Dept. of Chemistry, Katholieke University,
Leuven, Belgium, Visiting Professor- CNRS Lab, Laboratoire de Recherche sur
les, Polymers, UMR 7581- CNRS, 2-8 rue Henri Dunant, 94320 Thiais, Paris,
France. Supervised 27 PhD theses. Member of American Chemical Society (Rubber
Division), Fellow of New York Academy of Sciences, USA.Member of Indian
Membrane Society and Member of Polymer Society of India. Scientific
publications in International Refereed Journals (1986-2004) – 229
32. Prof Vijay Vasudevan, U
A) PHASE TRANSFORMATIONS IN NANOPARTICLES OF ALUMINUM
ALLOYS
JIXIONG HAN, MARTIN J. PLUTH, JAI A. SEKHAR AND VIJAY K
VASUDEVAN
Department of Chemical and Materials Engineering,
University of Cincinnati,
ABSTRACT
Nanoparticles of binary Al-Cu and Al-Zn alloys were
synthesized by plasma ablation of precursor ingots and the structure of these
particles as well as structural changes in these on aging at temperatures
between 65-190°C for times to 100h studied by electron diffraction, nanoprobe
energy dispersive x-ray spectroscopy and HRTEM. The particles were
supersaturated f.c.c. in both cases, but displayed a variation in the
individual particle composition when compared with the precursor bulk alloys. A
2-4 nm thick amorphous oxide layer was present around all the particles. On
aging the Al-Cu nanoparticles, a precipitation sequence consisting of nearly
pure Cu precipitates to theta' prime to the equilibrium theta was observed,
with all three forming only along the outer oxide-particle interior interface.
The structure of theta prime and its interface with the Al matrix was
characterized in detail. In the Al-Zn alloy, a spinodal structure was noted in
the as-synthesized nanoparticles, which coarsened on aging into a fine scale structure
composed of f.c.c twin-related platelets within which were contained platelets
with an h.c.p. structure. Nearly pure Zn precipitates, with an h.c.p.
structure, also formed along the oxide-particle interface and consumed the
spinodal structure with time. In the second part of the talk, the synthesis of
and precipitation behavior in ultrafine (5-25 nm) Al-Cu nanoparticles will be
presented. In the last part of the talk, results ofthe compaction, sintering
behavior and workability of nanoscale aluminium powders into bulk structures
will be presented. Nanoparticles of pure Al, with average diameter of 100 nm
and containing a 2-5 nm outer oxide layer, were cold-compacted, then sintered
at high temperatures. Both hot and cold rolling of the pressed pellets was also
utilized to assess workability and hardness after processing. Observations
revealed that the oxide scale remained intact on sintering at 500°C, but showed
evidence of breakage at higher temperatures, although in both cases a very
interesting Al matrix-Al oxide nanocomposite resulted. TEM observations
revealed that both constituents retained nanoscale dimensions, though there was
evidence of growth of the Al grains compared with the initial particles. High
densification, coupled with high hardness could be achieved. Cold- and hot-
rolling were effective methods for obtaining further increase in densification
and hardness. Support for this research from AFOSR under grant no.
F49620-01-1-0127, Dr. Craig S. Hartley, Program Monitor, is deeply appreciated.
B)
Chemical Vapor Synthesis of Iron and Iron Oxide
Nanoparticles
Vijay K. Vasudevan2,1, Jim
M. Vetrone3,1, G.-R. Bai1, Loren J. Thompson1,
and Jeffrey A. Eastman1; 1Argonne National Laboratory,
Materials Science Division, Argonne, IL USA; 2University of
Cincinnati, Department of Chemical and Engineering, Cincinnati, OH USA; 3Hinsdale
Central High School, Science Department, Hinsdale, IL, USA.
Iron and iron oxide nanoparticles were synthesized by
chemical vapor decomposition of n-butylferrocene precursor gas in a hot-walled deposition system. The
effects of variations in reactor chamber pressure, temperature, precursor
flow-rate, and oxygen:nitrogen supply gas ratio on the structure, composition,
size and size distribution of the particles were studied. The nanoparticles
produced in the reactor chamber were dispersed directly into ethylene glycol
without exposure to air. The particles were characterized by x-ray and electron
diffraction, nanoprobe energy-dispersive x-ray spectroscopy, and HRTEM. The results
indicate that nanoparticles with diameters ranging from 3 to 40 nm can be
produced controllably and with a narrow size distribution. Of the different
processing variables studied, oxygen content in the flow gas was observed to
have the most dominant effect on the structure, composition, and size of the
particles. Without oxygen, -iron and -iron
nanoparticles and diameters of 3-10 nm were observed. The presence of even a
small amount of oxygen in the flow gas led to the formation of fcc Fe3O4
(magnetite, Fd3m, a = 8.20 A)
nanoparticles, together with core-shell structures consisting of a -iron
metallic core surrounded by a shell of iron oxide. With increasing oxygen flow,
the nanoparticles were observed to increase in size. Concomitantly, for larger particles
the metallic core was found to exhibit the bcc -iron
structure. With further increase in oxygen in the flow gas, coarse particles of
-Fe2O3
(bcc, Ia3, a = 9.27Å) were observed,
together with fine particles of Fe3O4. Finally, at very
high oxygen partial pressure, the -Fe2O3 was
replaced by -Fe2O3
(Hematite, R3-c, a = 5.03Å, b
= 13.73Å c = 2.73Å). The
mechanisms of the synthesis of the nanoparticles and their structure,
composition, and magnetic properties will be discussed, as will the potential
for self-assembly of these particles into functional architectures
33. Dr K G K Warrier, RRL Trivandrum, Ceramic Technology Division, Regional Research
Laboratory (Council of Scientific & Industrial Research),
Trivandrum-695 019 (India)
A) NANO CRYSTALLINE RARE EARTH PHOSPHATES- NANO PARTICLES,
COATINGS AND COMPOSITES
KGK Warrier, R. Rohit and K. Rajesh, Ceramic Technology Division, Regional
Research Laboratory (Council of Scientific & Industrial Research),
Trivandrum-695 019 (India) and TRG Kutty, Bhabha Atomic Research Centre,
Mumbai-400 085 (India)
Rare Earth Phosphates are reported to be excellent
materials for high temperature applications due to their high temperature
stability, low thermal conductivity, moderate thermal expansion coefficient,
low reactivity with other ceramic oxides, and low sintering temperatures. They also possess low hardness, machinable
characteristics and low electrical conductivity. Usual synthetic methods report
submicron size rare earth phosphates, lanthanum and cerium phosphate in
particular. The present paper is an over
view of the various aspects related to synthesis of nano size rare earth
phosphates such as lanthanum, cerium and neodymium phosphates by a colloidal
aqueous sol-gel technique and further development of alumina-rare earth nano
composites. A few of the functional and
high temperature properties of the lanthanum phosphate and nano composites are
also presented. Possible scope of application of rare earth phosphates has been
highlighted in the lecture.
B) THERMAL EXPANSION BEHAVIOUR AND
MICROSTRUCTURAL FEATURES OF
ALUMINA-ALUMINIUM TITANATE NANO
COMPOSITES
SYNTHESIZED THROUGH COLLOIDAL PROCESSING
S. Anantha kumar, M. Jayasankar, P. Mukundan and KGK Warrier, Ceramic Technology Division, Regional Research Laboratory (Council of scientific & Industrial Research), Trivandrum-695 019 (India)
Abstract
Aluminium titanate is a well known high temperature ceramic having very low thermal expansion coefficient and has also found certain applications as crucibles, heating tubes and thermocouple sheaths. Alumina-aluminium titanate composites have found also applications especially with respect to the effective low thermal expansion as well as thermal shock resistance of such composites. The challenge in the preparation of successful composite remained in controlling the sintered microstructure of the composite. The present work is related to the fabrication of alumina-aluminium titanate nano composites containing 5-20% aluminium titanate as dispersed phase through a sol-gel colloidal route and sintering at about 1400oC. Such composites could be fabricated by extrusion of the precursor gels without involvement of polymer additives as practiced by conventional methods and sintered to high density. The mechanical properties, microstructural features and thermal expansion behaviour of such composites are presented. The possibility of application of such nano composites for high temperature is highlighted.
Brief
Biography : Dr K G K Warrier
Obtained PhD in Chemistry from the University of Kerala in Chemistry in 1978 and joined the Regional Research Laboratory (council of Scientific & Industrial Research) Trivandrum-695 019 (India) as scientist in the same year. He is currently Deputy Director and Head of the Ceramic Division of the Laboratory. He had also worked as DAAD Fellow at the Max Planck Institute, Stuttgart and Visiting Scholar in Argonne National Laboratory, USA. Dr. Warrier has contributed in the areas of chemistry of colloids, sol-gel and solid state synthesis of a variety of ceramic materials such as alumina abrasives, alumina and mullite matrix silicon carbide nano composites, mixed oxide nano catalysts, aerogels, nano rare earth phosphates, titania coatings and ultra and nano ceramic membranes. He is a referee for many International Journals and on the Editorial Board of Transactions of Indian Ceramic Society. He is a Fellow of the the Indian Institute of Ceramics and member, American Ceramics Society. Dr. Warrier is the Project leader for many research Projects financed by International Agencies, Government of India and Industrial Sector. He has 125 publications in the area of materials science and edited Proceedings of two International Conferences. He is a recognized research guide for PhD to many Indian Universities. He has supervised 9 Ph.D theses and has currently 9 PhD projects under progress.
34. Professor A. Vaseashta, Materials Processing & Characterization Laboratories Graduate Program in Physical Sciences
E-mail: vaseashta@marshall.edu Email: dravaseashta@charter.net
URL:
http://www.marshall.edu/nato-asi
Carbon
Nanotubes Based Devices and Sensors
ABSTRACT
The dimensionality of a system has a profound influence on its physical behavior. With advances in technology over the past few decades, it has become possible to fabricate and study reduced-dimensional systems in which electrons are strongly confined in one or more dimensions. Recent revolutionary progress in synthesis and characterization of carbon-based nanostructured materials and continuously emerging nanotechnologies has demonstrated tremendous potential towards the development of new devices and sensor designs with unique capabilities. Carbon-based nanostructures exhibit unique properties and morphological flexibility, which renders them inherently multifunctional and compatible with organic and inorganic systems. The applications of carbon nanotubes range from quantum wire interconnects, diodes and transistors for computing, capacitors, data storage devices, field emitters for flat panel displays and terahertz oscillators. Successfully contacted carbon nanotubes have exhibited a large number of useful quantum electronics and low dimensional transport phenomena, such as true quantum wire behavior, room temperature field effect transistors, room temperature single electron transistors, Luttinger-liquid behavior, the Aharonov-Bohm effect and Fabry-Perot interference effects. CNTs with aspect ratios of the order of 1000, coupled with a high conductivity, makes carbon nanotubes ideal candidate for field emitters. Recently there have been studies to utilize CNT as field emitters for display panels and cold-cathode for X-rays generation. On a different, yet related note, in clinical medicine, the current trend is to decentralize laboratory facility and conduct clinical trials employing direct reading, portable, lab-on-chip systems. A heightened awareness of the potential for inadvertent or deliberate contamination of environment and food and agricultural products has made decentralized sensing an important issue for several federal agencies. While analytical instruments and laboratory procedures are available for collecting the required data for myriad applications, these approaches are often unacceptably expensive and time consuming. Recent progress in nanostructured materials and its possible applications in chemical and biological sensors could have a significant impact on data collection, processing, and recognition. A nanotechnology based sensor platform will enable the direct electrical detection of biological and chemical agents in a label-free, highly multiplexed format over a broad dynamic range. This platform utilizes functionalized nanowires to detect molecular binding with exquisite sensitivity and selectivity without the need for chemical labels, amplification or complex sample preparation. The platform is capable of detecting broad range molecules, viz., DNA, RNA, proteins, ions, small molecules, cells and even the pH values. Detection is possible in both the liquid and gas phase and is highly multiplexable, allowing for the parallel detection of multiple agents. The presentation will outline unique device designs and chem.-bio sensors based on the nanotechnology.
Biography:
Ashok K. Vaseashta is a Professor of Physics
and Physical Sciences at