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  • Author: Yang Wang x
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Abstract

Large errors of low-cost MEMS inertial measurement unit (MIMU) lead to huge navigation errors, even wrong navigation information. An integrated navigation system for unmanned vessel is proposed. It consists of a low-cost MIMU and Doppler velocity sonar (DVS). This paper presents an integrated navigation method, to improve the performance of navigation system. The integrated navigation system is tested using simulation and semi-physical simulation experiments, whose results show that attitude, velocity and position accuracy has improved awfully, giving exactly accurate navigation results. By means of the combination of low-cost MIMU and DVS, the proposed system is able to overcome fast drift problems of the low cost IMU.

Abstract

The traditional clustering algorithm of Low-Energy Adaptive Clustering Hierarchy (LEACH) does not care about the residual energy of the cluster heads and the distance relationship of each node in the wireless sensor networks (WSNs). Each new round the cluster head is changed without any concern about the residual energy of the current cluster head, and the nodes join into a new cluster head without concern about the distance factor and the residual energy factor of all nodes in WSNs. To solve these problems in LEACH, this paper puts forward a distributed energy balance clustering algorithm, which takes into full consideration the residual energy of the cluster heads and the distance relationship between the base station and the cluster heads. The experimental results indicate that the proposed distributed energy balance clustering algorithm can prolong the lifetime of the networks more than LEACH, and the number of messages for selecting a new cluster head at the same time can be greatly reduced, which proves it as more suitable for practical applications.

Abstract

Since the traditional computer vision ranging algorithm is imperfect in pertinence and precision, night time monocular vision pedestrian ranging method is proposed for vehicular infrared night vision goggles. Firstly, the method calibrated the internal and external parameters of infrared night-vision goggles, then, it corrected distortion of collected Vehicular Infrared Night Vision Image, and finally it ranged objective pedestrians by using night time monocular vision pedestrian ranging algorithm. The experimental results show that this method has the characteristics of pertinence, high precision and good real-time, and has good practicability.

Abstract

An empirical network model has been developed to predict the in-plane thermal conductivities along arbitrary directions for unidirectional fiber-reinforced composites lamina. Measurements of thermal conductivities along different orientations were carried out. Good agreement was observed between values predicted by the network model and the experimental data; compared with the established analytical models, the newly proposed network model could give values with higher precision. Therefore, this network model is helpful to get a wider and more comprehensive understanding of heat transmission characteristics of fiber-reinforced composites and can be utilized as guidance to design and fabricate laminated composites with specific directional or specific locational thermal conductivities for structures that simultaneously perform mechanical and thermal functions, i.e. multifunctional structures (MFS).

A method on theoretical simulation of chromosome breaks in cells exposed to heavy ions

Background. The aim of this study is to assess an easy and quick method on simulating chromosome breaks in cells exposed to heavy charged particles.

Methods. The theoretical value of chromosome break was calculated, and the validated comparison with the experimental value by using a premature chromosome condensation technique was done.

Results. A good consistence was found to be appeared between the theoretical and experimental value.

Conclusions. This suggested that a higher relative biological effectiveness of heavy ions was closely correlated with its physical characteristics and besides, a safe approach on predicting chromosome breaks in cells exposed to heavy ions at off-line environment come to be considered. Furthermore, three key factors influencing the theoretical simulation was investigated and discussed.

Abstract

In this study, the wicking properties of ring and compact-siro ring spun staple yarns were compared. The twist level, which is related to the structure of the staple yarns, was found to significantly influence the wicking property of the two kinds of yarn. Polyester staple fibers with 1.33 dtex × 38 mm were selected as the staple fiber material, and the effect of the twist level on the wicking property was investigated using the capillary rise method. The results show that with a decreasing twist coefficient, the wicking height increases with a decrease in yarn compactness. The compact-siro spun yarn showed better wicking properties owing to it special ply yarn structure. Furthermore, the tension property of the yarns decreased significantly with a decrease in the twist coefficient. Compact-siro spinning was carried out to obtain staple yarns with lower twist coefficients, and the yarns showed great improvement in terms of yarn strength, fiber straightness, and wicking properties. Thus, compact-siro spinning is an efficient method to improve the wicking properties of staple yarns.

Abstract

In air/oil lubrication systems, the flow parameters, e.g., flow pattern, liquid film thickness, and air/oil flow rate, are of great importance to the transportation efficiency. In most cases, the on-going two-phase flow is annular flow with the oil moving along the tube wall and the air travelling at high speed in the center. This usually results in the formation of a thin oil film, the thickness of which is a key parameter determining the efficiency of the lubrication system. As the oil film thickness of the on-going air/oil flow varies dynamically, there is actually no applicable method for a non-intrusive test. In this paper, the use of electrical capacitance tomography (ECT) to investigate the air/oil flow has been studied. Capacitance measurements are made from an externally mounted electrode array in a non-invasive and non-intrusive manner. Both average and distributed oil film thicknesses can be calculated from the reconstructed ECT images. Simulation and experimental results show that the ECT technique can provide satisfactory results of online oil film thickness estimation

Abstract

Objectives To investigate the clinical features of tuberculosis (TB)-associated immune reconstitution inflammatory syndrome (TB-IRIS) in patients co-infected with HIV/TB or latent infection during highly active antiretroviral therapy (HAART).

Methods HIV-infected patients treated in the Third People’s Hospital of Shenzhen, China between March 2012 and March 2013 were recruited, and divided into 3 groups: 1) HIV/TB co-infection group (n = 50), 2) HIV/ MTB latent infection group (n = 50), and 3) HIV infection group (n = 50), with 12-month follow-up. Patients in the HIV/TB co-infection group were treated with HAART 2 weeks after TB therapy. Patients were assessed at different time-points.

Results The incidence and mortality rates of TB-IRIS were 40% and 10% in the HIV/TB co-infected patients, and 2% (and no mortality) in the HIV/MTB group. The HIV infected group did not display TB-IRIS or death. About 95% HIV/TB co-infected patients were 20-39 years old when TB-IRIS occurred, and 65% of the patients developed TB-IRIS 2 weeks after HAART. For the co-infection group, those with TB-IRIS (20/20, 100%) had fever, with a significantly higher incidence than those who did not develop TB-IRIS (6.7%, 2/30, P < 0.05). The patients with TB-IRIS in co-infection group displayed markedly higher clinical biochemical markers, acute phase reactants, increased CD4+ cell counts, and 2 log10-decreases of HIV RNA loads, compared with the patients not presenting with TB-IRIS (P < 0.05).

Conclusion HIV/TB co-infected patients presented with a high-risk of developing TB-IRIS during HAART treatment. Early diagnosis and treatment could decrease mortality rates in TB-IRIS.

Abstract

This study aimed to explore the effects of strike patterns and shoe conditions on foot loading during running. Twelve male runners were required to run under shoe (SR) and barefoot conditions (BR) with forefoot (FFS) and rearfoot strike patterns (RFS). Kistler force plates and the Medilogic insole plantar pressure system were used to collect kinetic data. SR with RFS significantly reduced the maximum loading rate, whereas SR with FFS significantly increased the maximum push-off force compared to BR. Plantar pressure variables were more influenced by the strike patterns (15 out of 18 variables) than shoe conditions (7 out of 18 variables). The peak pressure of midfoot and heel regions was significantly increased in RFS, but appeared in a later time compared to FFS. The influence of strike patterns on running, particularly on plantar pressure characteristics, was more significant than that of shoe conditions. Heel-toe running caused a significant impact force on the heel, whereas wearing cushioned shoes significantly reduced the maximum loading rate. FFS running can prevent the impact caused by RFS. However, peak plantar pressure was centered at the forefoot for a long period, thereby inducing a potential risk of injury in the metatarsus/phalanx.