Advanced Materials Research Vols. 472-475

Abstract: Many different methods have been developed for the measurement of transmission error (T.E.) at gears meshing. Each strategy improved the measurement performance is based on comparing the phases of sequence signals by counting the number of encoder pulses. The phase comparison method of T.E. is a dynamic measurement algorithm with lower angular resolution and many constrained conditions. This paper presents a new numerical algorithm aimed to provide the high accuracy information of instantaneous T.E. in the form of angular displacement. The analysis approach uses phase shift and demodulation technology in frequency domain to process the signals generated by encoders fixed on the both shaft of the gear driving mechanism. Finally, the algorithm is tested by simulation of gear meshing signal in Matlab software.

Abstract: For knowing the dielectric loss of high-voltage capacitive electrical equipment timely and mastering the electrical insulation of high voltage equipment effectively to ensure the reliable operation of these voltage equipments, an online monitoring system is designed in this paper based on the practical project. The system is made up of two parts including lower computer and upper computer. Using the microcontroller C8051F023 as the core of the lower computer and adopting an improved zero-crossing comparison method, the measurement of dielectric loss is realized and the data are sent to upper computer by wireless way. SQL2000 is used in the upper computer for data management, which can be real-time displayed, inquired and printed in report forms. At present, this monitoring system has successfully applied in the Houqiao 330 kV transformer substation in Ningxia. The operating results show that the system can meet well the online monitoring demand of the high voltage capacitive electrical equipment.

Abstract: ZnS thin films were deposited on glass substrates using chemical bath deposition. The zinc sulfate and thiourea were used as precursors along with a stable complexing agent of sodium citrate in ammonia/ammonium chloride (pH=10.5) buffer solution. The ratio of Zn and complexing agent was changed from 6:1 to 1:1 by varying concentrations of the complexing agent. X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-vis spectrophotometer were used to investigate the structure, micrograph and optical characteristics of the ZnS thin films respectively. The concentration of sodium citrate has an effect on the crystalline size and crystallization. For the as-deposited thin films, the values of transmittances and Eg are about 85% and 3.8 eV respectively. However, they are decreased to 75% and 3.4 eV respectively after annealing. In addition, the concentration of the complexing agent has no remarkable influence on both the transmittance and the energy gap. The results show that the ZnS thin films with resistivity of 4.34×104 Ωcm are suitable for optoelectronic applications.

Abstract: The fatigue life of the rotation platform of YTQH800 was evaluated based on transient dynamic calculation by using normal stress method in LMS VL. According to the evaluation, fatigue hot spots were predicted. A 3D sub-model with R=1 mm notches was built at one of the hot spots with the highest fatigue damage predicted previously. The stress history is obtained by transient dynamic computation. The detailed fatigue life was obtained by using notch stress method in LMS VL. The results provided technology supports to the structure optimum and improvement.

Abstract: In this paper, the design of rigid roller was optimized with finite element method, and processing technology of rigid roller was improved. A new type of flexible roller structure has been designed, and investigated its processing technology, which have important guiding significance in real productivity.

Abstract: Single point incremental forming (SPIF) is an innovative flexible sheet metal forming process which can be used to produce complex shapes from various materials. Due to its flexibility, it attracts a more and more attention in the recent decades. Several studies show that besides the major operating parameters, namely feed rate, tool radius, and forming speed etc., tool path is also an important processing parameter to affect the final forming component. In view of that, the present paper studies the influence of tool paths on the work piece quality by the finite element method coupled with the Continuum Damage Mechanics (CDM) model. The formability of incremental forming in different tool paths is also analyzed.

Abstract: In this paper, a DSP-based servo motion controller is developed for the horizontal flow wrapper, where the multi-axis servo drives and electronic anti-cut are designed to improve automatization and safety for the packaging system. This paper relates generally to high speed packaging machinery with electronic cam and more particularly to the process of electronic anti-cut, where product-out-of-registration conditions can be sensed and automatically passed without damage to the seal heads and without manual intervention.

Abstract: Taking Changguang high-sulfur coal and Yanzhou low-sulfur coal as experimental coal types, carrying out the experiment of Q-phase cement clinker co-generated from coal on two-stage polyphase reaction setup and conducting XRD analysis on the mineral composition in co-generation clicker sample, the result shows that the major mineral species in compositions of co-generation clinker are 2CaO•SiO2 and Q-phase. Taking one 330MW machine set 1004 (t.h-1) pulverized coal combustion boiler as analysis object, this paper carries out the preliminary analysis of the economic benefits that it may bring to power plant and cement enterprise by using co-generation technology. The analysis indicates that the objective boiler adopting belite Q-phase cement clinker technology, on the whole estimate of the resourceful benefit of coal fly ash and SO2 emission reduction benefit, the economic benefit of power plant obtained is 25,870 thousand yuan per year. The economic benefit cement enterprise obtained by using Belite Q-phase cement clinker to advance capacity is 40,581 thousand yuan per year.

Abstract: The ripple tray is a sieve tray without downcomers, in which the liquid contacts with the upward gas counter-currently. The hydrodynamics performance in ripple tray columns was investigated with the computational fluid dynamics (CFD) method. Various superficial gas velocity and liquid loads were simulated for the tray with cylindrical cross sections using the Euler-Euler method. The modeling results were validated by comparing the calculated liquid height on the ripple tray with the experimental values. The developed CFD model is found to be able to predict the two phase flow patterns in ripple tray columns and provide useful information for further design of ripple tray.

Abstract: In order to improve the efficiency of back gouging of large thick wall vessels and the work condition, and to reduce labor intensity, this paper presents a large-power, compact-structure and easy-and-simple-handled grinding machine for back gouging of outer circumferential weld. This grinding machine consists of grinding head, manipulator and guide rail. Since a grinding electric spindle, in which a grinding spindle is directly connected to a motor, is used in grinding head, the structure of the drive system is greatly simplified. Firstly the grinding head can be controlled closer to weld for back gouging in a certain pose by the arm back, up down traverse of the arm, longitudinal and lateral movement of the manipulator. Secondly, radial force can be produced between grinding head and weld line by the arm telescopic and radial force can be kept constant by a flexible device. The manipulator is set up on the guide rail, so it can control the grinding head to accomplish back gouging of multiple welds. When the grinding head is set up on the different functional manipulator, it can accomplish back gouging of internal or outer circumferential-weld and straight-weld. As the power of grinding machine is large and the process of back gouging is high automation, the time of back gouging can be reduced by one fifth to one third and the efficiency of back gouging is significantly improved, and security and comfort of back gouging of weld can be increased as well.