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The Dynamical Fingerprints of Multiferroic Materials
Randy Fishman, PhD
Distinguished R&D Research Scientist,
Oak Ridge National Lab, Oak Ridge, Tennessee
September 14, 2018
1:00 - 2:00 p.m.
Science Hall W1002
Inelastic neutron-scattering and optical measurements provide the dynamical “fingerprint”
for the multiferroic state of a material with coupled electrical and magnetic properties.
These experimental techniques have been used to identify the spiral and cycloidal
spin states in two very different multiferroic materials: 3.5\% Ga-doped CuFeO2 and
pure BiFeO3. By comparing the observed and calculated spectrum of spin excitations,
we conclude that the magnetic ground state of doped CuFeO2 is a distorted spiral with
a distribution of turn angles. Spectroscopic measurements of BiFeO3 in a magnetic
field reveal that the magnetic state is a cycloid that tilts from one hexagonal layer
to the next. For both materials, comparison between theory and experiment is used
to evaluate the microscopic interactions responsible for the magnetic state and its
multiferroic behavior.
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Cementitious Material Manufacture, Applications and Challenges
Christine A. Langton, PhD
Sr. Advisory Scientist,
Savannah River National Laboratory, Aiken, SC
September 28, 2018
4:00 - 5:00 p.m.
Science Hall W1002
Cementitious materials are the most commonly used construction materials in the world.
Plasters, mortars and concretes are the oldest engineered, multi component, building
materials. Cement chemistries, manufacturing methods, and mix designs have evolved
and matured over more than a thousand years. However, the magnitude and diversity
of the applications, desire for increased performance and environmental issues associated
with these materials demand continuous technology development. An overview of inorganic
cements and cementitious materials will be provided along with global challenges associated
with these materials. Examples of applications and technology needs associated with
energy production will be discussed. In addition, new cementitious materials designed
and implemented by the Savannah River National Laboratory for the US Department of
Energy (DOE) legacy waste management program will be described.
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Biological Structures on Solid electrodes for Diagnostics Sensing
James Burgess
Professor
The Graduate School
Augusta University
Adjunct Professor of Chemistry
Case Western Reserve University
November 16, 2018
1:00 - 2:00 p.m.
Science Hall W1002
Methods for microelectrode detection of cholesterol diffusion at the surface of cell(s)
have been developed for single cell studies, mouse tissues, and the human mucosa (inner
cheek). As summarized in our recent review article, cholesterol is a tightly regulated
major structural component of the cell plasma membrane (PM) where if forms stoichiometric
complexes with phospholipids and sphingolipids. The term “active cholesterol” refers
to PM cholesterol not complexed to lipids, a cholesterol state that arises above a
threshold mole fraction of cholesterol in the PM. Active cholesterol level in the
PM provides a control mechanism for cellular cholesterol homeostasis through its recognition
by membrane bound proteins that activate genes of cholesterol synthesis enzymes. Uptake
of LDL (bad cholesterol), production and release of HDL (good cholesterol) as well
as reversible storage of cholesterol by covalent modification are also regulated and
dependent on PM cholesterol (thermodynamic) activity: active cholesterol. The amount
of active cholesterol in the PM also exhibits a regulatory role in basal activity
of several biomolecular processes by direct binding to proteins and by indirect local
environmental effects within the PM. For these reasons, active cholesterol is a key
general biomarker for cellular dysfunction and we have demonstrated that it has specific
relevance to the cystic fibrosis disease state in cell and animal models. Continuing
collaboration with Tom Kelley in the Departments of Pediatrics and Pharmacology at
Case Western Reserve University, we aim to extend these trends to cystic fibrosis
in humans to provide diagnostic and management monitoring as well as to increase our
basic understanding of disease pathology at the cellular level. The general electrochemical
platform is also proposed for bloodless glucose analysis at the mucosa as a means
of preventing transmission of pathogens in healthcare settings. Batch-produced sensor
chips are being developed using state of the art micro/nano-manufacturing techniques
through collaboration with Minchul Shin in the Department of Mechanical Engineering
at Georgia Southern University.
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