Search

In this paper, a pre-mixed fuel model is proposed and a model predictive control(MPC) strategy is applied to a pre-mixed turbocharged natural gas engine. It is used in genset and the control objective is to track the target speed and air-fuel ratio(AFR), while resisting load disturbance. The pre-mixed fuel system makes the engine a strongly coupled two-input two-output system. Two methods for processing a crucial parameter in the model are presented, and two linearized models are obtained. Based on these two methods, same MPC control strategy is applied to these models respectively. The method 2 which uses polynomial fitting to treat this parameter as a function of system variables, more specifically reveals the coupling characteristics than method 1. The simulation results show that the MPC with method 2 has better control performance.

Modern applications are highly data-intensive, leading to the well-known I/O bottleneck problem. Scientists have proposed the placement of fast intermediate storage resources which aim to mask the I/O penalties. To manage these resources, three core software abstractions are being used in leadership-class computing facilities: IO Forwarders, Burst Buffers, and Data Stagers. Yet, with the rise of multi-tenant deployment in HPC systems, these software abstractions are: managed and maintained in isolation, leading to inefficient interactions; allocated statically, leading to load imbalance; exclusively bifurcated between the intermediate storage, leading to under-utilization of resources, and, in many cases, do not support in-situ operations. To this end, we present HFlow, a new class of data forwarding system that leverages a real-time data movement paradigm. HFlow introduces a unified data movement abstraction (the ByteFlow) providing data-independent tasks that can be executed anywhere and thus, enabling dynamic resource provisioning. Moreover, the processing elements executing the ByteFlows are designed to be ephemeral and, hence, enable elastic management of intermediate storage resources. Our results show that applications running under HFlow display an increase in performance of 3x when compared with state-of-the-art software solutions.

Harmonics have always been a problem to be solved in converter applications. Studying the source of harmonics and accurately predicting their content has also become one of the research directions. In this paper, the effect of sampling on the output harmonics in the actual system is fully considered. The cascaded H-bridge model based on phase-shifted carrier pulsewidth modulation (PSC-PWM) is modified by theoretical analysis and the accurate harmonic expression is obtained by applying the double-Fourier transform. The amplitude and phase of each harmonic can be accurately calculated and its presence can be better explained, which has great significance for eliminating specific harmonics and improving power quality. The correctness of the calculation is proved by simulation and experimental results.

This paper presents a new passive filter for grid-connected converters, named the LCPSL filter, which utilizes both the parallel and series LC trap branches to suppress the harmonics at switching frequency and its multiples. Particularly, the LCPSL filter can provide more attenuation and quality factor at the selected frequencies, and inherit the merits of the traditional LCL filter with −60dB/dec attenuation rate in high-frequency band. The basic parameter selection criteria and the parameter design procedure of the LCPSL filter are introduced. Besides, considering the simplicity of the single-current loop control, the stability regions of the resonance frequencies are derived for the filter design. Finally, the superiority and effectiveness of the proposed filter are proved by simulation results.

A novel seamless automatic transmission with only a single friction clutch, is focused in this paper. The dynamic model of the automatic transmission's downshifting process, is analyzed to establish the coordinating control strategy on the torque of the engine and the friction clutch. In the optimization, the torque gradient of the friction clutch and the power source are treated as the two control variables. Furthermore, the inequality constraints are applied on the control variables and the state variables. By solving the constrained Bolza problem with the numerical methods, the optimal state variables' trajectory is obtained. Besides, the coordinating control strategy is applied on the simulation model on the Matlab/Simulink platform as well as on bench-test, the results indicate that the characteristic of shifting without driving power interrupt during the downshift process is guaranteed and the dynamic performance is improved.

A rapid displacement sensor with a varifocal lens based on a method of fitting scan is proposed for 3D surface profiling. The focal length of the varifocal lens can be adjusted by varying the driving current. By detecting the reflective power of the reflected laser, the displacement can be obtained. By integrating a LabVIEW program based on a Levenberg-Marquardt algorithm in this system, the measuring speed can be substantially improved. Finally, the 3D surface profile of a step-height sample was successfully scanned by this displacement sensor.

With more and more attention on the grid current harmonic in recent years, many control schemes of the Pulse Width Modulation Voltage Source Converter (PWM-VSC) have been investigated. Conventional PI controller has shown limitations such as sensitivity to load and system parameter variation. Even the stability of the system can be threatened under a large and sudden load change. In this paper, the practical situation of a VSC for industrial Micro Grid (MG) is considered and an Artificial neural network (ANN) based control method is employed to solve the problem. Meanwhile, an on-line parameter tuning algorithm is introduced for its advantage of self-tuning and system character identification. The proposed control scheme is verified through simulation based on SABER software. The simulation results have shown the advantage of the proposed method and the performance of the parameter tuning session.

A pilot-scale experiment with a treating3capacity of 10 m per day was carried out for swine wastewater treatment by using of a moving bed biofilmreactor (MBBR). The reactor was start-up in 60 days period and run for a year, and an average removal rate of 82.9%for COD and 89.0% for ammonia were achieved, under a hydraulic retention time (HRT) of 12h, with influent COD and ammonia of 1686 iA 497 mg/L and 582 iA 126 mg/L, respectively. The effluent met the national discharge standard of pollutants for livestock and poultry breeding(GB 18596-2001) of China. The kinetics of organic carbon and ammonia removals in the MBBR was studied based on the Stover-Kin cannon model and the 1/2 order substrate removal model, respectively. Temperature coefficient "¦E"was introduced into the COD and ammonia removal models to describe the effects of the temperature. The model simulated results showed good agreements with experimental results. The model could be employed for the design of a full-scale MBBR process for simultaneous removal of organic carbon and ammonia from swine wastewaters.

The tidal-flow constructed wetland is a new type of constructed wetland proposed by the University of Birmingham, U.K. The principal of the wetland takes advantage of the rhythmical movement of wastewater and air which accelerates the alternation of aerobic and anaerobic to realize and enhance pollutant removal. This study focused on two aspects, the different operation performances for treating pollutants at a low temperature in winter between tidal-flow and traditional continuous-flow constructed wetlands, and the influences of treatment efficiency under different operating circumstances. The results showed that, under 0.2m3/m2/dhydraulic load, the removal rates of the three-cycles/d tidal flow constructed wetland for NH4+-N, COD and PO43--P could reach 48.57%, 68.96% and 29.02% respectively, which were about 30%, 20% and 20% higher than these in continuous flow wetlands, correspondingly.

The adsorption of Cu2+ from pharmaceutical wastewater by zeolite was studied in a batch adsorption system. Factors inflflflfluencing copper adsorption such as pH (1-5), adsorbent dosage (5-50 g/L) and contact time (20-600 min)were investigated. The equilibrium of adsorption process was established in about 480 min, while pH was 5 and adsorbent dosage was 30 g/L. After the adsorption equilibrium was achieved, the removal efficiency of Cu2+ was above 99%. Acomparison of the kinetic models on the overall adsorption rate showed that the adsorption system was best described by the pseudo second-order kinetics. The adsorption equilibrium datafifififit best with the Langmuir isotherm.

In this paper, design and implementation of WEB-based integrated system of office and business management was proposed in the context of one trading company. The systematic architecture and database design were introduced and the functions of various system components were analyzed. The technical details involved in implementation of Crystal Report chart display and Gridview mouse line events under .Net platform in the course of the system development were mainly expounded.

A theoretical study is presented on how to achieve higher second harmonic generation conversation efficiency of 797.822 nm diode laser. We optimize the nonlinear crystal LBO and resonant cavity through numerical calculations.

The modulation transfer spectroscopy in an ytterbium hollow cathod lamp at 399 nm is demonstrated. The frequency of a 399 nm laser is tightly locked by employing this technique.

The purpose of this paper is to design and implement a robot soccer game to conform RoboCup middle size league. First, according to the rules of RoboCup, we design the middle size soccer robot, which includes the independent image processing system and mechanical architecture. And the soccer robot equips the on-board computer system and interface circuits to make decisions. Second, the omnidirectional vision sensor of the vision system deals with the image processing and positioning for obstacle avoidance and target tracking. The boundary-following algorithm (BFA) is applied to find the important features of the field. In the control strategies, we present five state modes, which include the chasing ball mode, the catching ball mode, the shooting ball mode, obstacle avoidance mode and the defense mode. The soccer robot implemented for testing the performance of the proposed algorithm has shown that it chases a dynamic target successfully in the competition. And the experimental results confirm the methods finally.

In this paper, an appropriate definition of soft information is put forward. In order to discover soft sets application in recognizing soft information patterns, firstly analyze the basic definition of soft sets, make use of table to describe soft sets and give the conception of soft sets reduction according to the characters of soft sets. Then, the method is designed that recognizing soft information patterns by establishing the information table based on soft sets theory; at the same time the solutions are proposed corresponding to the different recognition vectors. This method with good maneuverability can operate collaterally and by batch so as to release the difficulty and complexity in information analysis by some extents.