Search Results

You are looking at 1 - 10 of 34 items for

  • Author: Wei Yang x
Clear All Modify Search
Open access

Wei Yang, Zhigang Yang and Maurizio Collu

ABSTRACT

The issue of the longitudinal stability of a WIG vehicle has been a very critical design factor since the first experimental WIG vehicle has been built. A series of studies had been performed and focused on the longitudinal stability analysis. However, most studies focused on the longitudinal stability of WIG vehicle in cruise phase, and less is available on the longitudinal static stability requirement of WIG vehicle when hydrodynamics are considered: WIG vehicle usually take off from water. The present work focuses on stability requirement for longitudinal motion from taking off to landing. The model of dynamics for a WIG vehicle was developed taking into account the aerodynamic, hydrostatic and hydrodynamic forces, and then was analyzed. Following with the longitudinal static stability analysis, effect of hydrofoil was discussed. Locations of CG, aerodynamic center in pitch, aerodynamic center in height and hydrodynamic center in heave were illustrated for a stabilized WIG vehicle. The present work will further improve the longitudinal static stability theory for WIG vehicle.

Open access

Shaocheng Tong, Gengjiao Yang and Wei Zhang

Observer-based fault-tolerant control against sensor failures for fuzzy systems with time delays

This paper addresses the problems of robust fault estimation and fault-tolerant control for Takagi-Sugeno (T-S) fuzzy systems with time delays and unknown sensor faults. A fuzzy augmented state and fault observer is designed to achieve the system state and sensor fault estimates simultaneously. Furthermore, based on the information of on-line fault estimates, an observer-based dynamic output feedback fault-tolerant controller is developed to compensate for the effect of faults by stabilizing the resulting closed-loop system. Sufficient conditions for the existence of both a state observer and a fault-tolerant controller are given in terms of linear matrix inequalities. A simulation example is given to illustrate the effectiveness of the proposed approach.

Open access

Yuanyuan Chen, Wei Yang and Chuang Xu

Abstract

Introduction: Vascular cell adhesion molecule 1 (VCAM-1) is a member of Ig superfamily. The aim of this study was to prepare highly specific polyclonal antibodies against bovine VCAM-1 and to evaluate the expression of VCAM-1 in the mammary lymph nodes of cows with subclinical mastitis.

Material and Methods: The VCAM-1 gene was cloned from bovine Peyer’s patches and inserted into the pGEX-4T-1 and pET-28a vectors. The recombinant plasmids pGEX-4T-1/VCAM-1 and pET-28a/VCAM-1 were transferred into Escherichia coli BL21 and the recombinant strains were induced by isopropyl-D-thiogalactoside to produce fusion proteins tagged with polyhistidine (His) and glutathione S-transferase (GST), respectively. The expressed fusion proteins His-VCAM-1 and GST-VCAM-1 were identified by SDS-PAGE and Western blot. His-VCAM-1 protein was used as an antigen to immunise Wistar rats and polyclonal antibody serum against VCAM-1 was obtained.

Results: The serum titre tested by indirect ELISA was 128,000 using GST-VCAM-1 as the well coating antigen. Western blots indicated that the antibody recognised recombinant VCAM-1 protein as well as endogenous VCAM-1. In addition, using qPCR and Western blot, VCAM-1 mRNA and protein expression levels were measured in dairy cows with subclinical mastitis. It was demonstrated that VCAM-1 levels in the mammary lymph nodes of the cows were significantly higher than those from healthy controls (P < 0.05).

Conclusion: These results are to our knowledge the first report that VCAM-1 expression in the mammary lymph nodes is elevated in dairy cows with subclinical mastitis.

Open access

Joe-Ming Yang, Zen-Wei Yang and Chien-Ming Tseng

ABSTRACT

In this study, numerical analysis was carried out by using the finite element method to construct the first mode shape of damaged stiffened plates, and the damage locations were detected with two-dimensional discrete wavelet analysis. In the experimental analysis, four different damaged stiffened structures were observed. Firstly, each damaged structure was hit with a shaker, and then accelerometers were used to measure the vibration responses. Secondly, the first mode shape of each structure was obtained by using the wavelet packet, and the location of cracks were also determined by two-dimensional discrete wavelet analysis. The results of the numerical analysis and experimental investigation reveal that the proposed method is applicable to detect single crack or multi-cracks of a stiffened structure. The experimental results also show that fewer measurement points are required with the proposed technique in comparison to those presented in previous studies.

Open access

Lingyun Y. Wei, Peixin X. Jiao, Trevor W. Alexander and Wen Zhu Yang

Abstract

Red osier dogwood (ROD) is an abundant shrub plant in Canada and other places in the world. It is rich in antioxidants such as quercetin, gallic acid and tyrosol. The objective of this study was to evaluate the effects of substituting barley silage with ROD in high-forage (HF) or high-grain (HG) diets on gas production (GP), dry matter (DM) disappearance (DMD) and fermentation characteristics in ruminal batch cultures. The study was a randomized design with 2 media pH (5.8 vs. 6.5) × 4 doses of ROD. An additional treatment of monensin and tylosin was added as a positive control for each pH level. The basic diet consisted of 60% barley silage and 40% barley grain for HF or 15% silage and 85% grain for HG diet. The barley silage was partly replaced with ROD at 0, 3, 6 or 12% in both diets (DM basis). Each diet was incubated for 24 h in culture bottles with three replicates for each treatment combination, and three runs on different days. The GP and DMD were greater (P<0.01) with media pH 6.5 vs. pH 5.8. The DMD linearly (P<0.01) decreased at pH 5.8 with increasing levels of ROD. Increasing ROD levels also linearly (P<0.01) decreased total VFA concentration and the proportion of propionate, and increased (P<0.01) the acetate to propionate ratio (A:P) at pH 5.8. Compared to the antibiotic treatment, the inclusion of ROD resulted in lower (P<0.02) DMD at pH 5.8, and a greater (P<0.01) proportion of acetate but a lower (P<0.01) proportion of propionate. These results indicated that the DMD of diets and the fermentation pattern were adversely affected by ROD at pH 5.8. However, the increased A:P along with the decreased DMD at pH 5.8, suggested a lower impact on fibre digestion than on starch digestion by ROD. Feeding ROD may therefore potentially reduce the incidence of rumen acidosis resulting from feeding HG diets to ruminants by decreasing starch digestion in the rumen.

Open access

Long Wei, Min Li, Qiang Fu, Yue Fan and Debin Yang

Abstract

In the acoustic fatigue experiment for hypersonic vehicle in simulated harsh service environment on ground, acoustic loads on the surface of test pieces of the vehicle need to be measured. However, for the normal microphones without high temperature resistance ability, the near field sound measurement cannot be achieved. In this work, on the basis of previous researches, an acoustic tubes array is designed to achieve the near field measurement of acoustic loads on the surface of the test piece in the supersonic airflow with high temperature achieved by coherent jet oxygen lance. Firstly, the process of designing this acoustic tubes array is introduced. Secondly, the equality of phase differences at the front and at the end of the tubes is stated and proved using a phase differences test with an acoustic tubes array whose design is presented in this text; therefore, the phase differences of signals acquired by microphones can be directly applied to beamforming algorithm to determine the acoustic load source. Finally, using above mentioned acoustic tubes array, measurement of acoustic load, with and without a test piece in the supersonic airflow made by the coherent jet oxygen lance, is conducted respectively, and the measurements results are analyzed.