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Ayyakkannu "Mani" Manivannan
Research Assistant Professor
West Virginia University
Department of Physics
P. O. Box 3615
Morgantown, WV 26506-3615
Tel: (304)293-3422 ext. 1429
Fax: (304)293-5732
E-mail: amanivan@wvu.edu
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Currently, our research group is pursuing research in the following areas:
i) DEVELOPMENT OF ELECTROCHEMICAL SENSOR FOR ON-SITE MONITORING OF
HEAVY METAL IONS IN COAL PROCESSING AND UTILIZATION (Funded by
DOE/EPSCoR, DOE/CAST)
Developing Boron Doped Diamond (BDD) based sensors for the detection of
ppb levels of trace metals (such as Hg, Zn, Cu, Pb, As, Cd, Fe) present
in coal utilized for power plants and also monitoring them at various
stages of coal processing. This research is based on our very promising
initial results in which ppb levels of Pb and Hg have been detected in
laboratory prepared solutions. It is argued that the BDD electrodes are
superior to other commonly used electrodes (such as glassy carbon) in
terms of their ruggedness, chemical stability, wide potential window and
lower background current. These advantages are important for the
simultaneous detection of a number of elements in some solution. This
will include: (i) Development of the calibration curves for different
elements using laboratory prepared solutions; (ii) Testing of samples
obtained from a coal preparation plant and an acid mine drainage site
and validation of the method employing other analytical techniques; and
(iii) Development of a portable unit for on-site detection. The project
will benefit from the collaborations provided by the Consolidation Coal
Co. and Prof. Fujishima of the University of Tokyo where the BDD
electrodes are synthesized.
ii) NEW STRATEGIES FOR DEWATERING COAL (funded by DOE/CAST)
An innovative research program on the combined experimental-modeling
studies of coal-water interactions and coal dewatering is proposed. The
experimental program will first focus on determining the relative
amounts of "free" and "bound" water in wet coals using analytical
techniques of thermogravimetric analysis, heat capacity measurements and
1H nuclear magnetic resonance. Laboratory scale dewatering experiments
will then be carried out by vacuum filtration and centrifugation,
combined with pulsed heating at microwave or IR (3300 cm-l) frequencies
to liberate the "bound" water. These investigations will be complimented
with modeling studies of the coal-water interactions and the effect of
centrifugation on dewatering from surface-bound water and coal pores.
This integrated experimental-modeling approach is an important component
of the proposed research since the results from the molecular-dynamics
simulations could provide unique technological insights that will
increase the efficiency of dewatering processes. Finally, scale-up of
the resulting successful approaches for coal dewatering will be
proposed at the conclusion of the two-year program.
iii) SYNTHESIS AND CHARACTERIZATION OF NANOMAGNETIC MATERIALS FOR SPINTRINIC APPLICATIONS
Co-doped TiO2 (anatase) nanoparticles were prepared from titanium
isopropoxide and investigated for the possible existence of room
temperature ferromagnetism (RTF). These powders were characterized by
X-ray diffraction (XRD) followed by through studies of the temperature
and magnetic field dependence of the magnetization by Squid
magnetometry. Co-doping was 10 at% in all the cases and no phase other
than anatase could be detected, and there is no RTF in these powders
prepared as such. But, to our surprise we found that RTF can be achieved
in this system by annealing them in controlled H2 atmospheres. For T ≈
300K, a hysteresis loop with coercivity Hc = 200 Oe is observed for an
annealing time of 1hr in H2. These observations suggest the vital role
of oxygen in Co doped TiO2 system and its influence in manipulating
paramagnetic to ferromagnetic nature. This opens the path way to RTF
with exchange interaction becoming important at higher temperatures.
iv) DEVELOPMENT OF NOVAL MOLECULAR RADICAL EPR OXIMETRY PROBES (ECAS program)
The purpose of this research is to develop a novel particulate probe
for electron paramagnetic resonance (EPR) that can significantly improve
the ability to measure the partial pressure of O2 (pO2) under normal as
well as biologically pertinent conditions in vitro and in vivo. Accurate
quantification of molecular oxygen concentration in chemical and
biological systems is an important area of research. Although there are
few particulate probes available, they have limitations and, in
particular, suffer a nonlinear dynamic range response for oxygen
detection. Our present research will focus on a prototype of a class of
crystalline paramagnetic probes, lithium naphthalocyanine (LiNc) and
aims to facilitate the use of this probe using EPR.
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