Effect of Quarls on the Blowout Stability and Emission of Pollutants of a Liquid-Fueled Swirl Burner

Stringent emissions standards for NOx and carbon monoxide (CO) prompt lean combustor development. With this motivation, combustion stability issues emerge since the desired operating point approaches the lean blowout limit. In this paper, an atmospheric, 15 kW lean premixed prevaporizing-type swirl burner, equipped with a plain jet airblast atomizer, was investigated at various atomizing pressures and combustion air flow rates, using quarls from 0 deg to 60 deg in 15 deg steps. Both the 15 deg and the 30 deg quarls provided a 42% higher lean blowout stability on average in terms of mean mixing tube discharge velocity, compared to the baseline burner. However, the superior stability regime was encumbered by a rapidly increasing CO emission. In parallel, the NOx emission vanished due to the more dilution air and incomplete combustion. The 60 deg quarl provided a moderately extended blowout stability limitation, while the NOx emission slightly increased and the CO emission reduced compared to the baseline burner.

Maximum Allowable Dynamic Load of Mobile Manipulators with Stability Consideration

High payload to mass ratio is one of the advantages of mobile robot manipulators. In this paper, a general formula for finding the maximum allowable dynamic load (MADL) of wheeled mobile robot is presented. Mobile manipulators operating in field environments will be required to manipulate large loads, and to perform such tasks on uneven terrain, which may cause the system to reach dangerous tip-over instability. Therefore, the method is expanded for finding the MADL of mobile manipulators with stability consideration. Moment-Height Stability (MHS) criterion is used as an index for the system stability. Full dynamic model of wheeled mobile base and mounted manipulator is considered with respect to the dynamic of non-holonomic constraint. Then, a method for determination of the maximum allowable loads is described, subject to actuator constraints and by imposing the stability limitation as a new constraint. The actuator torque constraint is applied by using a speed-torque characteristics curve of a typical DC motor. In order to verify the effectiveness of the presented algorithm, several simulation studies considering a two-link planar manipulator, mounted on a mobile base are presented and the results are discussed.

Multi-Index Nonlinear Coordinated Control of TCBR and Hydro-Generator Excitation

As a new FACTS device, thyristor controlled braking resistor (TCBR) is one of the effective devices to enhance transient stability of generator. In this paper, a coordinated controller for TCBR and hydro-generator excitation system with the multi-index nonlinear coordinate control method based differential geometry theory is proposed. By means of Hartman-Grobman theorem, differential geometry multi-index nonlinear control (DGMINC) design method can reassign the closed-loop system eigenvalues of linear approximate system to the nonlinear system via appropriately selecting output function parameter matrix. Therefore, the system can get good control performance. The simulation results show that TCBR and generator excitation system controlled by this coordinate control strategy can decrease the generator acceleration area rapidly when the severe fault occurred and increase deceleration area significantly after the fault is cleared. So that, power system transient stability limitation improved significantly.

Analysis of the Factors Affecting Stability of Hard Cutting System

The flutter in the hard cutting has a significant impact on the efficiency of production, the quality processed, the environment in processing, the cost, and the life of the machines and tools . However, the application of the method named numerical simulation in MatLab predicted the stability limitation of the hard cutting system, analyzed the influence of cutting system dynamics parameters on the stability limitation of system, at the same time, an experimental verification of hard cutting had been carried out. And the results of analysis showed that improving the system stiffness K and cutting system damping ratio ζ, cutting the stiffness coefficient Kc and the direction coefficient , adjusting the cutting speed to the correct, reducing the amount of turning ap, decreasing the tip radius of circular arc , increasing the feeding f can be used as the methods of vibration reducing in the system. So the results of the research provide reference for the reasonable choice of cutting parameters.

Preparation and Characterization of Resveratrol-Loaded Hydroxylpropyl-β-Cyclodextrin

The purpose of this research was to prepare Resveratrol-loaded Hydroxylpropyl-β-Cyclodextrin, and to solve solubility and stability limitation of Res. Res-loaded HP-β-CD was prepared by freeze-dryer , then its solution was adjusted to different pH value, and finally its identification and content were analyzed by UV spectrophotometer. Res-loaded HP-β-CD prepared here was water soluble, and after pH adjustment, its appearance was improved.