Missouri University of Science and Technology

About: Missouri University of Science and Technology is a education organization based out in Rolla, Missouri, United States. It is known for research contribution in the topics: Artificial neural network & Control theory. The organization has 9380 authors who have published 21161 publications receiving 462544 citations. The organization is also known as: Missouri S&T & University of Missouri–Rolla.

Implementation of adaptive critic-based neurocontrollers for turbogenerators in a multimachine power system

Abstract: This paper presents the design and practical hardware implementation of optimal neurocontrollers that replace the conventional automatic voltage regulator (AVR) and the turbine governor of turbogenerators on multimachine power systems. The neurocontroller design uses a powerful technique of the adaptive critic design (ACD) family called dual heuristic programming (DHP). The DHP neurocontrollers' training and testing are implemented on the Innovative Integration M67 card consisting of the TMS320C6701 processor. The measured results show that the DHP neurocontrollers are robust and their performance does not degrade unlike the conventional controllers even when a power system stabilizer (PSS) is included, for changes in system operating conditions and configurations. This paper also shows that it is possible to design and implement optimal neurocontrollers for multiple turbogenerators in real time, without having to do continually online training of the neural networks, thus avoiding risks of instability.

Effects of Fluoroethylene Carbonate (FEC) on Anode and Cathode Interfaces at Elevated Temperatures

Abstract: The use of electrolyte additives is one of the most effective and economical ways to improve battery performance by stabilizing the electrode/electrolyte interface. In this work, we identified that fluoroethylene carbonate (FEC), which is one of the important electrolyte additives, had different impacts on anode and cathode, by investigating a graphite anode and a LiMn2O4 cathode through electrochemical analyses at room and elevated temperatures. In the anode side, the solid electrolyte interphase (SEI) layer derived from FEC exhibited a lower interfacial resistance and excellent thermal stability, showing excellent rate capability and improved cycle retention of cells. In contrast, poor cycling retention and a rapid increase in the interfacial resistance of the cathode were observed at elevated temperature. The poorer performance of the cathode in the FEC-containing cell at elevated temperature was attributed to the formation of a thicker surface layer and to increased Mn dissolution catalyzed by HF, which resulted from FEC dehydrofluorination initiated or accelerated by elevated temperature. Accordingly, it is suggested that the amount of FEC in a full cell must be optimized to minimize the adverse effects of FEC on cathode. © 2015 The Electrochemical Society. [DOI: 10.1149/2.0071509jes] All rights reserved.

Nature of Charge Carriers in Disordered Molecular Solids: Are Polarons Compatible with Observations?

Abstract: Polaronic theories for charge transport in disordered organic solids, particularly molecularly doped polymers, have been plagued by issues of internal consistency related to the magnitude of physical parameters. We present a natural resolution of the problem by showing that, in the presence of correlated disorder, polaronic carriers with binding energies $\ensuremath{\Delta}\ensuremath{\sim}50--500\mathrm{meV}$ and transfer integrals $J\ensuremath{\sim}1--20\mathrm{meV}$ are completely consistent with the magnitudes of field and temperature dependent mobilities observed.

IGBT and Diode Loss Estimation Under Hysteresis Switching

Abstract: This paper presents a power loss estimation method for insulated-gate bipolar transistors (IGBTs) and diodes that operate under hysteresis switching. The method relies on datasheet information and three measurements in a phase leg: phase current, one IGBT switching gate signal, and the dc bus voltage across the phase leg. No parasitic models, thermal analysis, or slow simulations are required, and measurements can be provided from simulations or experiments. The method is validated for periodic pulsewidth modulation, then for aperiodic hysteresis switching. Results show that the proposed method is accurate while maintaining simplicity. It is promising for implementation in combined thermoelectric simulations and design optimization.

Observation of upper tropospheric sulfur dioxide‐ and acetone‐pollution: Potential implications for hydroxyl radicaland aerosol formation

Abstract: Aircraft-based measurements of sulfur dioxide, acetone, carbon dioxide, and condensation nuclei (CN) were made over the north-eastern Atlantic at upper tropospheric altitudes, around 9000 m. On October 14, 1993, strong SO2- and acetone-pollution (both up to 3 ppbv) were observed, which were accompanied by a CO2-enhancement of up to 6 ppmv, and large CN-concentrations of up to about 1500 cm−3 (for radii ≥ 6 nm). CN, excess CO2, and to a lesser degree also acetone, were positively correlated with SO2. Air mass trajectory analyses indicate, that most of the air masses encountered by our aircraft originated from the polluted planetary boundary layer of the North-Eastern U. S. approximately 4–5 days prior to our measurements, and that polluted boundary layer air experienced fast vertical transport to the upper troposphere as well as horizontal transport across the Atlantic. From our data we conclude, that in the polluted air mass around 9000 m altitude HOx-formation, photochemical SO2-conversion to gaseous H2SO4, and eventually also CN-formation by homogeneous bimolecular (H2SO4-H2O) nucleation may have taken place with enhanced efficiency.