CMAQ Modeling and Analysis of Trace Gases and Biomass Burning

The Community Multiscale Air Quality (CMAQ) model was extended to simulate nitrous acid (HONO) and nocturnal isoprene in Houston, and biomass burning over the United States (U.S.). The linear dependence of HONO heterogeneous reaction on the relative humidity (RH) was parameterized by scaling the reaction rate. The simulation scenarios conducted for September 2013 in Houston improved modelled-HONO concentrations and reduce the bias for NO2 compared to observations. Similarly, simulations were conducted for nocturnal isoprene in September 2013 using the U.S. Environmental Protection Agency’s (EPA’s) National Emissions Inventory of 2011 (NEI 2011). The results were evaluated against measurements collected at eight Automated Gas Chromatographs sites maintained by the Texas Commission on Environmental Quality. The comparisons demonstrated an overestimation before midnight versus an underestimation after midnight. Analyses identified the underestimated wind speed as the major factor contributing to the overestimation of simulated isoprene, and uncertainties in the nocturnal isoprene anthropogenic emissions in the NEI 2011 over industrial areas in Houston as the major factor contributing to the underestimation. A sensitivity experiment with adjusted anthropogenic emissions of isoprene in the later part of the night yielded closer isoprene predictions after midnight. Finally, an offline physical plumerise module was applied to the Fire Inventory from NCAR (FINN) to simulate an intense fire episode in August 2012 in the western U.S. It was found that the base simulation with default FINN emissions underestimated the CO concentrations in the mid-troposphere. The sensitivity experiment increasing fire emissions by a factor of five improved the model simulation, whereas the experiment reducing plume height showed little change. Model results indicated that during the fire event more than 40 ppb O3 were generated near the fire sources. Three-year simulations from April to October 2012–2014 showed the contributions of biomass burning to the mean maximum daily 8-hour (MDA8) surface O3 and the ambient fine particulate matter (PM2.5) was limited to regional scales. Near the fire sources, the contributions to PM2.5 and MDA8 were more than 20 µg m-3 and 8–9 ppb, respectively for wildfires, and 10–12 µg m-3 and 3–4 ppb, respectively for prescribed fires.Earth and Atmospheric Sciences, Department o

Service Life Prediction of Electrolytic Capacitors in Urban Rail Transit Based on Analytical Iteration and GM (

In the power supply of urban rail transit system, electrolytic capacitors are used in large numbers. They suffer from inevitable ripple currents; such ripple currents generate heat dissipation, which shortens their service life seriously. To increase the reliability of the whole power supply system, the aging process of electrolytic capacitors must be evaluated, so that their service life could be predicted and measures could be taken in advance before their failures. When they are applied into the power supply system, the accuracy of conventional approaches is somewhat lowered, owing to the existence of unpredictable ripple current and ambient temperature variations. In this paper, we build an analytical ripple model to offer online aging monitoring of electrolytic capacitors. After that, a GM(2,1) model is adopted to predict service life with higher accuracy than conventional approaches

Different Angiogenic Potentials of Mesenchymal Stem Cells Derived from Umbilical Artery, Umbilical Vein, and Wharton's Jelly

Human mesenchymal stem cells derived from the umbilical cord (UC) are a favorable source for allogeneic cell therapy. Here, we successfully isolated the stem cells derived from three different compartments of the human UC, including perivascular stem cells derived from umbilical arteries (UCA-PSCs), perivascular stem cells derived from umbilical vein (UCV-PSCs), and mesenchymal stem cells derived from Wharton’s jelly (WJ-MSCs). These cells had the similar phenotype and differentiation potential toward adipocytes, osteoblasts, and neuron-like cells. However, UCA-PSCs and UCV-PSCs had more CD146+ cells than WJ-MSCs (P<0.05). Tube formation assay in vitro showed the largest number of tube-like structures and branch points in UCA-PSCs among the three stem cells. Additionally, the total tube length in UCA-PSCs and UCV-PSCs was significantly longer than in WJ-MSCs (P<0.01). Microarray, qRT-PCR, and Western blot analysis showed that UCA-PSCs had the highest expression of the Notch ligand Jagged1 (JAG1), which is crucial for blood vessel maturation. Knockdown of Jagged1 significantly impaired the angiogenesis in UCA-PSCs. In summary, UCA-PSCs are promising cell populations for clinical use in ischemic diseases

2013 International Conference on Electrical and Information Technologies for Rail Transportation

Proceedings of the 2013 International Conference on Electrical and Information Technologies for Rail Transportation (EITRT2013) collects the latest research in this field, including a wealth of state-of-the-art research theories and applications in intelligent computing, information processing, communication technology, automatic control, etc. The objective of the proceedings is to provide a major interdisciplinary forum for researchers, engineers, academics and industrial professionals to present the most innovative research on and developments in the field of rail transportation electrical and information technologies. Contributing authors from academia, industry and the government also offer inside views of new, interdisciplinary solutions

Taking Traction Control to Task:High-Adhesion-Point Tracking Based on a Disturbance Observer in Railway Vehicles

Railway vehicles have been based on a wheel-rail system since the system's origination. Therefore, the adhesion-coupling behaviour between wheel and rail is the fundamental element of railway traction [1]. However, low vehicle wheel-rail adhesion caused by high humidity, rain, snow, oil, or decomposing leaves is a common problem that can cause damage to some elements of the traction system and decrease traction performance [2]. It may even give rise to safety problems and reduce comfort, not to mention delays and their corresponding economic impact. Good traction control to ensure the system is working at high adhesion point is therefore critical and mandatory for the traction control units (TCUs) [2]-[6