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.

Distribution and Volatilization of Organic Compounds Following Uptake by Hybrid Poplar Trees

Abstract: Hybrid poplar trees were exposed to eleven organic compounds in hydroponic systems. The eleven contaminants were common pollutants with a wide range of physio-chemical properties such as the octanol-water partition coefficient, Henry's constant, vapor pressure, and molecular weight. Contaminants, 14C-labeled, were introduced into the root zone, and contaminant transport and fate were examined. Aqueous concentrations were monitored throughout each experiment as was vapor phase concentrations in the air stream passing over the leaves. At experiment conclusion, plant tissues were oxidized to determine 14C concentrations. The uptake, distribution, and volatilization of these contaminants varied greatly among the 11 contaminants in the study. Uptake and translocation of the contaminants ranged from < 0.3% (of the applied 14C-labeled compound) for 1,2,4-trichlorobenzene to 20% for benzene. Volatile compounds were volatilized from the leaves. Volatilization in the transpiration stream was related to the...

NMR Studies of Zinc, Copper, and Iron Binding to Histidine, the Principal Metal Ion Complexing Site of Amyloid-β Peptide

Abstract: Amyloid-beta (Abeta), the major component of senile plaques in Alzheimer's disease, is known to complex transition metal ions mainly through histidine residues. In this study, using 1H NMR titration experiments, we show that histidine binds strongly to Zn(II), Cu(II), and Fe(III) ions at a biologically relevant pH (pH 7.4), with a stoichiometry of Zn(II): histidine binding of 1:2. The observed deshielding of the chemical shifts and relative line broadening indicate that Fenton-active Cu(II) and Fe(III) bind to histidine relatively more efficiently as compared to Zn(II). Parallel studies showed that glutamic acid and aspartic acid are relatively inefficient in metal ion binding. From these studies, we suggest that Abeta-chelated Zn(II) is readily displaced by Cu(II) and Fe(III) ions and leads to a propagation of oxidative stress.

Shear Strengthening of a PC Bridge Girder with NSM CFRP Rectangular Bars

Abstract: Bridges worldwide are falling into a state of disrepair caused by deterioration, traffic overloading, and poor maintenance. It is estimated that over 100,000 of the half million existing bridges in the US are in need of repair or replacement. Although the full replacement option could be viable, it is an expensive solution with significant disruption of service. This paper focuses on the use of carbon fiber reinforced polymer (CFRP) rectangular bars installed as near surface mounted (NSM) reinforcement for shear strengthening in conjunction with an externally bonded pre-cured CFRP laminate to increase the flexural capacity of a prestressed concrete (PC) bridge girder. The specimen, which was removed from an overloaded bridge in Kansas was strengthened and tested in the laboratory. Test results showed that the proposed NSM reinforcement technique represents an effective solution to increase shear capacity.

Economic Dispatch of a Hybrid Microgrid With Distributed Energy Storage

Abstract: This paper introduces a distributed economic dispatch strategy for microgrids with multiple energy storage systems. This strategy overcomes the challenges of dynamic couplings among all decision variables and stochastic variables in a centralized dispatching formulation. The proposed strategy can be implemented in the microgrid central controller as multiple problems with simplified and decomposed formulations. It can also be implemented in the local controllers and managed by the central controller. Numerical studies and experimental results illustrate the effectiveness of the proposed dispatching systems.

Fault-Tolerant Control of MMC With Hot Reserved Submodules Based on Carrier Phase Shift Modulation

Abstract: Reliability is one of the most important challenges for the modular multilevel converter (MMC), which is composed of a large number of power electronics submodules (SMs). In order to increase the system reliability, the reserved SMs are often utilized. A novel strategy is proposed in this paper to implement the fault-tolerant control of MMC with the hot reserved SMs based on the carrier phase shift modulation. All the SMs, including the hot reserved SMs, work in the operating mode and the standby mode in turns. A rotating sliding choice box is adopted to select the operating SMs and the corresponding phase-shift angles, which enables the equal burden of each SM. Once the faults are detected and localized, the reserved SMs can simultaneously replace the bypassed failed SMs, which guarantees the fault-tolerant operation with a nearly seamless transition and very short recovery time. Furthermore, the line cycle is set as the rotating period in the control strategy, without increasing much switching loss. The mismatch pulses are greatly reduced as well. This technique can also be easily implemented in a DSP or microcontroller. Simulations in MATLAB/Simulink and experiments based on a downscaled MMC prototype have verified the feasibility and effectiveness of the proposed control strategy.