Search

Since external loads affect the sealing performance of bolted flanged joints, this paper calculated external loads of bolted flanged joints by using CAESAR II software and evaluated the effects of external loads on the sealing performance from the viewpoint of changes in contact gasket stress and flange rotation by using ANSYS software. The FE results showed that the contact gasket stress decreases a lot at the tension side and increases a little at the compression side. The paper also evaluated the stress distribution in bolted flanged joints subjected to external loads. The results suggested that the flange rotation and the overall stress increased compared with that of flange without external loads. External loads can induce unexpected leakage and strength failure of the bolted flanged joints during operation.

In order to acquire a suitable ink for ink-jet printing technology, a graphene oxide ink was explored based on the GO aqueous dispersion. The GO dispersion was characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The average particle diameter and zeta potential of the GO dispersion was determined by zeta potential & particle size analyzer. The GO ink is composed of 1,2-propanediol, diethylene glycol monobutyl ether, glycerol, polyvinyl pyrrolidone (PVP) and GO dispersion. The surface tension and viscosity of the GO ink was tested by surface tension meter and rheometer. The GO ink was inkjet printed on polyethylene terephthalate (PET) substrate. The optimal inkjet printing parameters were obtained and the printing quality was characterized by confocal laser scanning microscopy. The results show that the GO ink is suitable for inkjet printing technology and the morphology of the GO film with one printing pass has good uniformity.

This paper proposes a space vector motor control system based on DSP four-legged bridge topology A three-dimensional space vector control principle based on four-bridge arm three-phase inverter is introduced with a MATLAB model using space vector Motor Control Algorithm instead of traditional Motor Control method. A DSP experimental setup is also carried out to verify the control theory and simulation result. The experiment and simulation results show that the speed control system helps the asynchronous motor to achieve the consistent response characteristics with separately excited DC machine. When the motor doesn't work or the load is unstable, asynchronous motor can still achieve excellent electrical characteristics with the proposed speed control system, such as quick start, small overshoot and static torque ripple.

Network coding (NC) in wireless sensor network (WSN) has been shown to achieve considerable throughput gains relative to traditional routing networks. While the data throughput capacity of WSNs is unknown, the scaling of capacity with the number of nodes has recently received increasing attention. This paper proposes a Complex Field Network Coding-based Multipath Routing (CFNC-MR) in WSN. The performance of this routing method is studied using NS2 and evaluated in terms of the packet overhead, packet delivery ratio, and packet loss ratio when a packet is transmitted. Simulation shows that the approach is efficient, promising and applicable in WSNs.

The dual power supply system is widely used in our daily life. When power instantaneously switched between the main power and the stand-by power supply, the voltage fluctuations had the varying degree influence on machines. Based on the principle of correlation coefficient of two waveforms and instantaneous reactive power theory, the dual-power supply automatic and instantaneous switching device without disturbance is provided in this paper. The equipment could identify and isolate the broken-down power source in 5ms. At the same time, power supply keeps continuous meeting the requirements of power quality without voltage drop.

Based on the systematic analysis of geological and hydrogeological conditions of Baisha River, the scope of study area and boundary conditions are determined. This paper builds the water quantity model of researched region with the software of MODFLOW. The observational data according to temporal sequence are identified and validated by the water quantity model. Then, we choose the optimal hydrogeology parameters to simulate future groundwater levels. The simulated results show that ground water levels have rebounded to some extent. According to the amount of groundwater exploitation in the past 10 years, the available groundwater is between 1.4~1.6×106m3/a from 2012 to 2015. But the actual amount is only 1.2×106m3/a. Therefore, the region can increase the amount of groundwater exploitation to make more fully use of water resources .But mining can not do without moderation. We should guarantee the safety of groundwater, and then water resources can be fully sustainable utilization. Finally, the essay requests for rational use and protection of the groundwater.

The paper presents digital closed loop fiber-optic current sensor (FOCT)’s optical path which combines integrated optical modulator and polarization beam splitter as optimum combination, as well as numerical analysis on insertion loss of traditional optical path scheme which consists of straight waveguide and optical path proposed by ABB. It shows that loss causes equivalent noise current which will affect the sensitivity of photo detector. The calculation and experiment confirm that loss of optical path is an important factor for FOCT’s sensitivity, and optical path composed of integrated optical phase modulator with Y-Branch profile and polarization beam splitter can effectively reduce the insertion loss and improve sensitivity of the system.

The author chose three kinds of commercial resins for blank experiment and then added oxidants.We studied that how removal rate changed under different temperature and picked the D001-cc as the best supporter in desulfurization procedure. And heteropolyacid was supported onto D001-cc with different loadings,the results showed 10% was the optimal condition.

In article we analyzes the conventional experimental method’s characteristic and expatiates the predominance of numerical simulation experiment. The numerical simulation experiment is applied in teaching text in civil engineering school of Henan Polytechnic University and obtained the very good teaching effect. Numerical simulation experiment can simulate routine experiment and get curve and data which can’t be obtained by normal test. Numerical simulation experiment also can simulate large-scale project which can't be done by conventional experiment.

With the development of science and technology, the quality of the product is better and better. Consequently, in the time-ended life tests, zero-failure data is of frequent occurrence． So the evaluation of the product’s life has important meaning and greatly practical value． While Bayesian estimation is a very effective method about the analysis of the product’s zero-failure data. In the paper, Bayesian estimation of failure probability of zero-failure data are take out, combined linear fitting method and the software of Matlab, the method to ascertain types of product’s life distribution is come out according to zero-failure data. Finally calculation is performed regarding to zero-failure data of a certain model engine, and ascertain the equation of the engine’s life distribution.

In order to improve the fitting of garment on shoulder, the measurement of 275 young females aged from 20-24 were taken with 3D-body scanner; the position data relating to the shoulder was conducted using cluster analysis, and extracted 5 characteristic indices that contained almost information of shoulder shape; the rationality of clustering shoulder shape to 4 different types was tested and verified through using one-way analysis of variance; then established the Fisher Discriminant Analysis (FDA) model to identify the young females’ shoulder shape. The result showed that the forecasting model of Fisher Discriminant Analysis (FDA) had excellent performance, high prediction accuracy, so it provided a new method to identify young females’ shoulder shape.

Using Martin Meter from Japan to measure 110 young women body. Using SPSS software for correlation analysis of measurement data, then selecting width, thickness and weight as elements used for establishing leg girth regression models. Adopting backward regression method to choose variable further, and establishing Multiple Linear regression model, Multivariate Quadratic regression model, Multivariate Cubic regression model to predict the girth of each part of leg which related to clothing. After testing and comparing the effect of each model, choosing out the best fitting modle for each part. The validity of modles were tested by randomly selecting 20 young women’s leg data,comparing with manual measurements, gaining satisfactory results. So as to provide an important technical support for human leg two-dimensional non-contact measurement and be further applied to research on medical compression stockings.

Ceramic supported ferric oxide composites were synthesized by impregnation- precipitation (I) and sol-gel (II) methods using FeSO4as a precursor. We investigated the effect of the calcination temperatures on the structure, morphology, and agglomeration of supported ferric oxide. It has been found that Fe2O3was stabilized when the as-synthesized composites were calcinated at 330-360 °C under 10% (v/v) O2/N2mixture, and the calcination temperature was chosen as 350°C . The SEM images demonstrated that for the composite I, which was prepared by method (I), Fe2O3 nanoparticles were distributed on the surface and pores of the ceramic; while for the composite II, which was synthesized by method (II), Fe2O3thin layer was covered the surface of the ceramic. EDS analysis showed 7.9% (wt) ferric oxide had been supported on the composite I and up to 13.3% (wt) ferric oxide on the composite II. XPS analysis revealed that the valence of iron was +3 on both composites. Fe2O3/ceramic composites were used as the catalysts for low temperature wet Flue Gas Desulphurization (FGD), and demonstrated higher SO2removal efficiency. Because of the excellent hydrophilicity of ceramic and high dispersibility of Fe2O3 on ceramic surface, this catalyst had high SO2removal efficiency at 60°C even at pH2O3/ceramic composites, prepared by a simple, reproducible impregnation-precipitation and sol-gel method, was an inexpensive, active catalyst for S(IV) catalytic oxidation in wet FGD process in an economical feasible temperature range.

Concerning the effect of the parameter uncertainty caused by environmental temperature, we present a robust control algorithm for the fiber optical voltage transformer (FOVT) to achieve optimized dynamic performance. The principle of the FOVT based on closed-loop detection is analyzed and the system model is established. Based on the system model and the optimized dynamic performance index, the robust controller is investigated to suppress the effect of the forward gains variation. Furthermore, we give a design criterion in terms of linear matrix inequality (LMI) for the proposed control. Finally, the experimental results show that the control has strong robustness against parameter uncertainty for improving the dynamic performance of the FOVTs.

The equipment combat unit is usually in the aggregated state when operate mission, and the mission maintainability is an important factor for its operational effectiveness. There were kinds of parameter to measure the mission maintainability, such as Mean Downtime and Mission Time to Restore Function. Based on the analyses to layers and performance of the aggregated equipment combat units, the signification of aggregated equipment combat units’ Mission Time to Restore Function was adopted and analyzed, the simulation method and simulation flow for the mobile mission of aggregated equipment combat units were given, and then the simulation model under ExSpect was constructed. Finally, an example was used to prove the simulation model.

This paper reviews shearography and its applications for testing of aircraft composite structures and honeycomb-based specimen. Shearography is a laser-based interferometry in conjunction with the digital imaging processing technique for full-field measurement of surface deformation. It reveals defects in an object by looking for defect-induced deformation anomalies. It does not require special vibration isolation, and with the development of a small and mobile measuring device (portable inspection system), it can be employed easily in field/factory environments.

According to requirements of the natural and economic laws, the environmental management of watershed distinction is inevitable for improvement of watershed environmental management effect. In the paper, the Nine-division Principle is set forth, i.e. division by watershed, area, sequence, stage, type, grade, duty, right and policy through analysis of watershed distinction management in system theory and behavior economics, and of regional sub-characteristics of watershed in geographical elements, functions and economic developments. Under the guide of Nine-division principle, the idea on the environmental management of watershed distinction is reflected and implemented smoothly by dividing watershed environmental and economical function region, ways of optimizing the watershed environmental management, and creating conditions for implementation of environmental management of watershed distinction.