A5014436559- Photosynthetic Processes and Mechanisms
- Catalytic Processes in Materials Science
- Iron oxide chemistry and applications
- Quantum Dots Synthesis And Properties
- Spectroscopy and Quantum Chemical Studies
- ZnO doping and properties
- Catalysis and Oxidation Reactions
- Catalysts for Methane Reforming
- Advanced Thermoelectric Materials and Devices
- Water Systems and Optimization
- Chalcogenide Semiconductor Thin Films
- Copper-based nanomaterials and applications
- Minerals Flotation and Separation Techniques
- Advanced Chemical Physics Studies
- Zeolite Catalysis and Synthesis
- Electronic and Structural Properties of Oxides
- Electrocatalysts for Energy Conversion
- Hemoglobin structure and function
- Network Security and Intrusion Detection
- Gas Sensing Nanomaterials and Sensors
- Semiconductor materials and interfaces
- Graphene research and applications
- Water Treatment and Disinfection
- Machine Learning in Materials Science
- Advanced Condensed Matter Physics
Washington University in St. Louis
2010-2020
Oak Ridge National Laboratory
2010
Saint Louis University
2010
University of Alaska Fairbanks
2006-2007
National Institute of Standards and Technology
2006-2007
Massachusetts Institute of Technology
2004-2005
Thermoelectric devices that utilize the Seebeck effect convert heat flow into electrical energy and are highly desirable for development of portable, solid state, passively-powered electronic systems. The conversion efficiencies such quantified by dimensionless thermoelectric figure merit (ZT), which is proportional to ratio a device's conductance its thermal conductance. High ZT (>2) has been achieved in materials via all-scale hierarchical architecturing. This efficiency holds at high...
Abstract Wide bandgap perovskite oxides with high room temperature conductivities and structural compatibility a diverse family of organic/inorganic materials are significant interest as transparent conductors active components in power electronics. Such must also possess mobility to minimize consumption enable high-frequency applications. Here, we report n-type BaSnO 3 films grown using hybrid molecular beam epitaxy conductivity exceeding 10 4 S cm −1 . Significantly, these show mobilities...
The BATtle of the Attack Detection ALgorithms (BATADAL) is most recent competition on planning and management water networks undertaken within Water Distribution Systems Analysis Symposium. goal battle was to compare performance algorithms for detection cyber-physical attacks, whose frequency has increased in last few years along with adoption smart technologies. design challenge set C-Town network, a real-world, medium-sized distribution system operated through programmable logic...
In this manuscript we address the efforts reported in literature on direct conversion of methane and carbon dioxide into higher value products. The abundance these two greenhouse gases makes them potentially useful for chemical syntheses. However, strong intramolecular bonds render both molecules chemically inert thermodynamically stable. Thus, significant energy inputs as well properly designed catalytic systems are required their reactions. addition to traditional processes, new...
Ceria (CeO2) is a promising catalyst for the reduction of carbon dioxide (CO2) to liquid fuels and commodity chemicals, in part because its high oxygen storage capacity, yet fundamentals CO2 adsorption, activation, on ceria surfaces remain largely unknown. We use density functional theory, corrected onsite Coulombic interactions (GGA+U), explore various adsorption sites configurations stoichiometric reduced (110), latter with either an in-plane vacancy or split vacancy. find that both (110)...
A useful feedback loop: insights from theoretical calculations are used for rational design of nanosensors and elucidating surface interactions.
Fuel production from sunlight using mixed metal oxide photocatalysts is a promising route for harvesting solar energy. While photocatalytic processes can operate with high efficiency UV light, it remains challenge of paramount importance to drive them visible light. Engineering the electronic energy band structure oxides through judicious control atomic composition increasing light photoresponse. The goal this paper develop simple (MMOBS) method predict oxides. Several materials in Ti−Fe−O...
A spectral thermometer: The conformation of molecules on a metallic nanoparticle's surface is sensitive to temperature variations and can be easily monitored in situ by surface-enhanced Raman scattering (SERS). Excitation the nanoparticle for SERS concurrently induce photothermal effect whereby light absorbed released as heat. From spectra, changes during derived (see picture). Detailed facts importance specialist readers are published "Supporting Information". Such documents peer-reviewed,...
This work presents the first all-pigment microscopic model of a major light-harvesting complex plants and attempt to capture dissipative character known structure.
Abstract Nonradiative relaxation of high-energy excited states to the lowest state in chlorophylls marks first step process photosynthesis. We perform ultrafast transient absorption spectroscopy measurements, that reveal this internal conversion dynamics be slightly slower chlorophyll B than A . Modeling with non-adiabatic molecular simulations uncovers a critical role played by different side groups two molecules governing intramolecular redistribution wavefunction, leading, turn,...
Accurate models of carrier transport are essential for describing the electronic properties semiconductor materials. To best our knowledge, current following framework Boltzmann equation (BTE) either rely heavily on experimental data (i.e., semi-empirical), or utilize simplifying assumptions, such as constant relaxation time approximation (BTE-cRTA). While these offer valuable physical insights and accurate calculations in some cases, they often lack sufficient accuracy -- particularly...
Smart water infrastructures are prone to cyber-physical attacks that can disrupt their operations or damage assets. An algorithm was developed identify suspicious behaviors in the different components of a smart distribution system. The incorporated multiple modules anomaly-detection techniques recognize types anomalies real-time monitoring and control data. Trained artificial neural networks were used detect unusual patterns do not conform normal operational behavior. Principal component...
The structures of the clean and hydrated hematite $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ $(1\overline{1}02)$ surfaces were investigated using density functional theory, free energies in chemical equilibrium with water calculated as a function temperature oxygen partial pressure ab initio thermodynamics. At $298.15\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, predicted lowest-energy surface, $20\phantom{\rule{0.3em}{0ex}}\mathrm{Torr}$...
We demonstrated room-temperature gas sensing of volatile organic compounds (VOCs) using SnO2 nanostructured thin films grown via the aerosol chemical vapor deposition process at temperatures ranging from 450 to 600 °C. investigated film's response presence three classes VOCs: apolar, monopolar, and biopolar. The synthesis was optimized, with most robust observed for 550 °C as compared other temperatures. role film morphology, exposed surface planes, oxygen defects were explored experimental...
Metabolic network reconstructions are often incomplete. Constraint-based and pattern-based methodologies have been used for automated gap filling of these networks, each with its own strengths weaknesses. Moreover, since validation hypotheses made by tools require experimentation, it is challenging to benchmark performance make improvements other than that related speed scalability.We present BoostGAPFILL, an open source tool leverages both constraint-based machine learning generation in...
All transparent conducting materials (TCMs) of technological practicality are n‐type; the inferior conductivity p‐type TCMs has limited their adoption. In addition, many relatively high‐performing require synthesis temperatures >400 °C. Here, room‐temperature pulsed laser deposition copper‐alloyed zinc sulfide (Cu x Zn 1‐ S) thin films (0 ≤ 0.75) is reported. For 0.09 0.35, Cu S high conductivity, up to 42 cm −1 at = 0.30, with an optical band gap tunable from ≈3.0–3.3 eV and...
We report on the electronic and optical properties of two theoretically predicted stable spinel compounds form ZnB2O4, where B = Ni or Cu; neither compound has been previously synthesized, so we compare them to studied p-type ZnCo2O4 spinel. These new materials exhibit spin polarization that is ideal for spintronics applications, broad conductivity maxima near valence band edge facilitate dopability. show 3d electrons octahedrally coordinated Zn atom fall deep within do not contribute...
We use density functional theory (DFT) calculations to investigate the mechanism of CO2 hydrogenation methanol on a reduced ceria (110) catalyst, which has previously been shown activate CO2. Two reaction channels are identified: (1) COOH pathway via carboxyl intermediate and (2) HCOO formate intermediate. While formaldehyde (H2CO) appears be key for synthesis, other intermediates, including carbine diol, formic acid methanol, not feasible due their high formation energies. Furthermore,...
The spectroscopic properties of the peridinin–chlorophyll a–protein (PCP) from coral symbiotic dinoflagellate Symbiodinium have been characterized by application various ultrafast optical spectroscopies including femto- and nanosecond time-resolved absorption picosecond fluorescence (TRF) at 77 K. Excited state peridinin Chl a their intramolecular interaction characteristics obtained global fitting analysis directed kinetic modeling data sets compared to counterparts known for PCP...