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Open access

Wei Zhang, Longfu Zhou, Yibing Shi, Chengti Huang and Yanjun Li

Soft-Fault Diagnosis of Analog Circuit with Tolerance Using FNLP

A new soft-fault diagnosis approach for analog circuits with parameter tolerance is proposed in this paper. The approach uses the fuzzy nonlinear programming (FNLP) concept to diagnose an analog circuit under test quantitatively. Node-voltage incremental equations, as constraints of FNLP equation, are built based on the sensitivity analysis. Through evaluating the parameters deviations from the solution of the FNLP equation, it enables us to state whether the actual parameters are within tolerance ranges or some components are faulty. Examples illustrate the proposed approach and show its effectiveness.

Open access

Houxu Huang, Jie Li and Jiuqi Wei

Abstract

The rock in plastic region is divided into numbers of elements by the slip lines, resulted from shear localization. During the deformation process, the elements will slip along the slip lines and the displacement field is discontinuous. Slip lines around circular opening in isotropic rock, subjected to hydrostatic stress are described by the logarithmic spirals. Deformation of the plastic region is mainly attributed to the slippage. Relationship between the shear stresses and slippage on slip lines is presented, based on the study of Revuzhenko and Shemyakin. Relations between slippage and rock failure are described, based on the elastic-brittle-plastic model. An analytical solution is presented for the plane strain analysis of displacements around circular openings in the Generalized Hoek-Brown rock. With properly choosing of slippage parameters, results obtained by using the proposed solution agree well with those presented in published sources.

Open access

Wei Li and Qian Huang

Abstract

In order to solve the problem that current avoidance method of shipwreck has the problem of low success rate of avoidance, this paper proposes a method of intelligent avoidance of shipwreck based on big data analysis. Firstly,our method used big data analysis to calculate the safe distance of approach of ship under the head-on situation, the crossing situation and the overtaking situation.On this basis, by calculating the risk-degree of collision of ships,our research determined the degree of immediate danger of ships.Finally, we calculated the three kinds of evaluation function of ship navigation, and used genetic algorithm to realize the intelligent avoidance of shipwreck.Experimental result shows that compared the proposed method with the traditional method in two in a recent meeting when the distance to closest point of approach between two ships is 0.13nmile, they can effectively evade.The success rate of avoidance is high.

Open access

Yun Wei, Ying Yu, Lifeng Xu, Wei Huang, Jianhua Guo, Ying Wan and Jinde Cao

Abstract

Vehicle emission calculation is critical for evaluating motor vehicle related environmental protection policies. Currently, many studies calculate vehicle emissions from integrating the microscopic traffic simulation model and the vehicle emission model. However, conventionally vehicle emission models are presented as a stand-alone software, requiring a laborious processing of the simulated second-by-second vehicle activity data. This is inefficient, in particular, when multiple runs of vehicle emission calculations are needed. Therefore, an integrated vehicle emission computation system is proposed around a microscopic traffic simulation model. In doing so, the relational database technique is used to store the simulated traffic activity data, and these data are used in emission computation through a built-in emission computation module developed based on the IVE model. In order to ensure the validity of the simulated vehicle activity data, the simulation model is calibrated using the genetic algorithm. The proposed system was implemented for a central urban region of Nanjing city. Hourly vehicle emissions of three types of vehicles were computed using the proposed system for the afternoon peak period, and the results were compared with those computed directly from the IVE software with a trivial difference in the results from the proposed system and the IVE software, indicating the validity of the proposed system. In addition, it was found for the study region that passenger cars are critical for controlling CO, buses are critical for controlling CO and VOC, and trucks are critical for controlling NOx and CO2. Future work is to test the proposed system in more traffic management and control strategies, and more vehicle emission models are to be incorporated in the system.

Open access

Wen-Zhi Zeng, Chi Xu, Jing-Wei Wu, Jie-Sheng Huang and Tao Ma

Abstract

A facility of BaPS (Barometric Process Separation) and indoor incubation experiments were used to determine the effect of soil salinity on soil respiration and nitrogen transformation. The rates of soil respiration, gross nitrification, denitrification, ammonium and nitrate nitrogen concentrations and relevant soil parameters were measured. Results showed that soil respiration and nitrification and denitrification rates were all affected by soil salinity. Furthermore, the effect of soil salinity level on nitrification and denitrification rates had a threshold value (EC1:5 = 1.13 dS/m). When soil salinity level was smaller to this threshold value, the rates of nitrification and denitrification increased with soil salinity while they were reduced when soil salinity level was larger than the threshold value. Moreover, the changing law of soil respiration rate with soil salinity was similar with the nitrification and denitrification rates while the variation tendency was opposite. In addition, the transformation form urea to ammonium and nitrate nitrogen was also reduced with the increase of soil salinity and the reduced effect could be expressed by exponential functions.

Open access

Chi Xu, Wen-Zhi Zeng, Jing-Wei Wu and Jie-Sheng Huang

Abstract

Intermittent irrigation has attracted much attention as a water-saving technology in arid and semi-arid regions. For understanding the effect of intermittent irrigation on water and solute storage varied from irrigation amount per time (IRA), irrigation application frequency (IRAF), irrigation intervals (IRI) and even soil texture (ST), intermittent irrigation experiment was carried out in 33 micro-plots in Inner Mongolia, China. The experiment results were used for the calibration and validation of HYDRUS-1D software. Then 3 ST (silty clay loam, silty loam, and silty clay), 5 IRA (2, 4, 6, 8, and 10 cm), 4 IRAF (2, 3, 4, and 5 times) and 4 IRI (1, 2, 3, and 4 days) were combined and total 240 scenarios were simulated by HYDRUS-1D. Analysis of variance (ANVOA) of simulated results indicated that ST, IRA, and IRAF had significant effect on salt and nitrate nitrogen (NO3 -N) storage of 0-40 cm depth soil in intermittent irrigation while only ST affected soil water storage obviously. Furthermore, salt leaching percentage (SLP) and water use efficiency (WUE) of 0-40 cm depth were calculated and statistical prediction models for SLP were established based on the ANOVA using multiple regression analysis in each soil texture. Then constraint conditions of soil water storage (around field capacity), salt storage (smaller than 168 mg·cm−2), WUE (as large as possible) in 0-40 cm depth and total irrigation water amount (less than 25 cm) were proposed to find out the optimal intermittent irrigation strategies. Before sowing, the optimal irrigation strategy for silty clay loam soil was 6 cm IRA, 3 times IRAF, and 2 days IRI respectively. For silty loam and silty clay soils, IRA, IRAF, and IRI were 8 cm, 3 times, and 2 days respectively.

Open access

Wen-Zhi Zeng, Tao Ma, Jie-Sheng Huang and Jing-Wei Wu

Abstract

Soil nitrogen transportation and transformation are important processes for crop growth and environmental protection, and they are influenced by various environmental factors and human interventions. This study aims to determine the effects of irrigation and soil salinity levels on nitrogen transportation and transformation using two types of experiments: column and incubation. The HYDRUS-1D model and an empirical model were used to simulate the nitrogen transportation and transformation processes. HYDRUS-1D performed well in the simulation of nitrogen transportation and transformation under irrigated conditions (R 2 as high as 0.944 and 0.763 for ammonium and nitrate-nitrogen simulations, respectively). In addition, the empirical model was able to attain accurate estimations for ammonium (R 2 = 0.512-0.977) and nitrate-nitrogen (R 2 = 0.410-0.679) without irrigation. The modelling results indicated that saline soil reduced the rate of urea hydrolysis to ammonium, promoted the longitudinal dispersity of nitrogen and enhanced the adsorption of ammonium-nitrogen. Furthermore, the effects of soil salinity on the nitrification rate were not obviously comparable to the effects of the amount of irrigation water. Without irrigation, the hydrolysis rate of urea to ammonium decreased exponentially with the soil salinity (R 2 = 0.787), although the nitrification coefficient varied with salinity. However, the denitrification coefficient increased linearly with salinity (R 2 = 0.499).

Open access

Mei Li, Mei Wang, Shouhai Li, Kun Huang, Wei Mao and Jianling Xia

Abstract

Calcium and zinc salts of dimer fatty acids (DFA-Ca and DFA-Zn) were synthesized using direct neutralization and metathesis technologies, respectively. The adduct of maleic anhydride and methyl eleostearate (MAME) was also converted to the corresponding zinc soap (C22TA-Zn) and calcium soap (C22TA-Ca) by the two different synthetic routes. Mixed Ca/Zn salts between DFA-Ca and DFA-Zn, and between C22TA-Zn and C22TA-Ca were used as thermal stabilizers for poly(vinyl chloride) (PVC). The PVC thermal stability was determined using Congo red test, discoloration test, torque rheological analysis and TGA. Dynamic mechanical properties were also tested. Results indicated that the DFA-Ca/DFA-Zn thermal stabilizer from direct neutralization technology was found to be superior to that of the metathesis product. The C22TA-Ca/C22TA-Zn thermal stabilizer from direct neutralization method had overall superior thermal stability, and displayed modulus and glass transition comparable to that of metathesis product. Direct neutralization method was more excellent and convenient than metathesis technology.

Open access

Wen-Zhi Zeng, Jie-Sheng Huang, Chi Xu, Tao Ma and Jing-Wei Wu

Abstract

For improving the understanding of interactions between hyperspectral reflectance and soil salinity, in situ hyperspectral inversion of soil salt content at a depth of 0-10 cm was conducted in Hetao Irrigation District, Inner Mongolia, China. Six filtering methods were used to preprocess soil reflectance data, and waveband selection combined by VIP (variable importance in projection) and b-coefficients (regression coefficients of model) was also applied to simplify model. Then statistical methods of partial least square regression (PLS) and orthogonal projection to latent structures (OPLS) were processed to establish the inversion models. Our findings indicate that the selected sensitive wavebands for the 6 filtering methods are different, among which the multiplicative signal correction (MSC) and standard normal variate methods (SNV) have some similar sensitive wavebands with unfiltered data. Derivatives (DF1 and DF2) could characterize sensitive wavebands along the scale of VNIR (350-1100 nm), especially the second derivative (DF2). The sensitive wavebands for continuum-removed reflectance method (CR) have protruded many narrow absorption features. For orthogonal signal correction method (OSC), the selected wavebands are centralized in the range of 565-1013 nm. The calibration and evaluation processes have demonstrated the second order derivate filtering method (DF2) combined with waveband selection is superior to other processes, for it has high R 2 (larger than 0.7) both in PLS and OPLS models for calibration and evaluation, by choosing only 156 wavebands from the whole 700 wavebands. Meanwhile, OPLS method was considered to be more suitable for the analyzing than PLS in most of our situations.