Energy Efficiency Improvement of Heavy-Load Mobile Hydraulic Manipulator with Electronically Tunable Operating Modes

The conventional hydraulic drive system for a heavy-load mobile manipulator is usually operated under single mode, such that both inlet/outlet and potential energy losses are large to lower the energy efficiency. In this paper, a novel electro-hydraulic drive system is presented to improve energy efficiency. Extended control degrees of freedom are obtained utilizing the independent metering valve and electronic controlled pump. Then, multiple operating modes are carried out pertaining to the cylinder, valve, and pump. To achieve both optimal energy efficiency and precise motion tracking, both multi-mode switching and multi-variable controller are designed to accommodate with time-varying and uncertain load characteristics. As a consequence, the inlet, outlet, and potential energy losses can be decreased simultaneously. The experimental validation is conducted by using a three-joint manipulator in a 2 t excavator. A duty cycle of movement including all three actuators and covering full load quadrants is used to evaluate the efficiency improvement. Compared with the conventional load sensing system, the proposed multi-mode switching system using the pump pressure with valve meter-in control mode yields a 25.8% energy-saving ratio. Furthermore, the pump flow with valve mete-out control mode yields a 35.3% energy-saving ratio. Using this combined control mode, higher efficiency can be obtained due to the minimum inlet losses, but faster dynamic response together with higher overshoot will appear. It is proved that the energy efficiency is improved, while the motion tracking performance is not degraded by introducing the multi-mode switching

Input Estimation Algorithms for Reentry Vehicle Trajectory Estimation

Fast and accurate estimation of trajectory is important in tracking and intercepting reentry vehicles. Validating model is a real challenge associated with the qverall trajectory estimation problem. Input estimation technique provides a’solution to this challenge. Two input estimation algorithms were introduced based on different assumptions about the input applied to the model. This investigation presents approaches consisting of an extended Kahnan filter and two input estimation algorithms to identify the reentry vehicle trajectory in its terminal phase using data from a single radar source. Numerical simulations with data generated from two models demonstrate superior capabilities as measured by accuracy compared to the extended Kalman filter. Evaluation using real flight data provides the consistent results. The comparison between two input estimation algorithms is also presented. The trajectory estimation approaches based on two algorithms are effective in solving the reentry vehicle tracking problem

KINEMATICAL ANALYSIS OF TWO DIFFERENT FOREHAND BADMINTON DROP SHOTS TECHNIQUES

The purpose of this study was to compare the kinematics variables between badminton forehand regular and reverse slice drop shots. The participants were eight elite male players. Eight Vicon Motion T20s System cameras (300Hz) were used to record the 3D kinematic data, which were computed by Visual 3D software. All the variables were tested by Wilcoxon rank analysis of variance nonparametric statistical test with the significant level at a = .05. The results showed that there was significant difference between the two forehand drop shots in the racket pan angle. The strategy of two drop shots seems different. That might because the reverse slice drop was with greater shoulder abduction movement than the regular drop shot. The players performed reverse slice drop shot might because that the abduction movement was similar with the smash

Application of the machine learning LightGBM model to the prediction of the water levels of the lower Columbia River

Due to the strong nonlinear interaction with river discharge, tides in estuaries are characterised as nonstationary and their mechanisms are yet to be fully understood. It remains highly challenging to accurately predict estuarine water levels. Machine learning methods, which offer a unique ability to simulate the unknown relationships between variables, have been increasingly used in a large number of research areas. This study applies the LightGBM model to predicting the water levels along the lower reach of the Columbia River. The model inputs consist of the discharges from two upstream rivers (Columbia and Willamette Rivers) and the tide characteristics, including the tide range at the estuary mouth (Astoria) and tide constituents. The model is optimized with the selected parameters. The results show that the LightGBM model can achieve high prediction accuracy, with the root-mean-square-error values of water level being reduced to 0.14 m and the correlation coefficient and skill score being in the ranges of 0.975–0.987 and 0.941–0.972, respectively, which are statistically better than those obtained from physics-based models such as the nonstationary tidal harmonic analysis model (NS_TIDE). The importance of subtide constituents in interacting with the river discharge in the estuary is clearly revealed from the model results

Ecological functions of uncultured microorganisms in the cobalt-rich ferromanganese crust of a seamount in the central Pacific are elucidated by fosmid sequencing

Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Acta Oceanologica Sinica 34 (2015):92-113, doi:10.1007/s13131-015-0650-7.Cobalt-rich ferromanganese is an important seafloor mineral and is abundantly present in the seamount crusts. Such crusts form potential hotspots for biogeochemical activity and microbial diversity, yet our understanding of their microbial communities is lacking. In this study, we used a cultivation-independent approach to recover genomic information and derive ecological functions of the microbes in a sediment sample collected from the cobalt-rich ferromanganese crust of a seamount region in the central Pacific. A total of 78 distinct clones were obtained by fosmid library screening with a 16S rRNA based PCR method. Proteobacteria and MGI Thaumarchaeota dominated the bacterial and archaeal 16S rRNA gene sequence results in the microbial community. Nine fosmid clones were sequenced and annotated. Numerous genes encoding proteins involved in metabolic functions and heavy metal resistance were identified, suggesting alternative metabolic pathways and stress responses that are essential for microbial survival in the cobalt-rich ferromanganese crust. In addition, genes that participate in the synthesis of organic acids and exoploymers were discovered. Reconstruction of the metabolic pathways revealed that the nitrogen cycle is an important biogeochemical process in the cobalt-rich ferromanganese crust. In addition, horizontal gene transfer (HGT) events have been observed, and most of them came from bacteria, with some occurring in archaea and plants. Clone W4-93a, belonging to MGI Thaumarchaeota, contained a region of gene synteny. Comparative analyses suggested that a high frequency of HGT events as well as genomic divergence play important roles in the microbial adaption to the deep-sea environment.China Ocean Mineral Resources R & D Association (COMRA) Special Foundation (No. DY125-15-R-03 and DY125-13-E-01); the National Natural Science Foundation of China (No. 41276173); the Zhejiang Provincial Natural Science Foundation of China (No. LQ13D060002) and the Scientific Research Fund of the Second Institute of Oceanography, SOA (No. JT1305).2016-04-1

Experimental Free-Space Distribution of Entangled Photon Pairs over a Noisy Ground Atmosphere of 13km

We report free-space distribution of entangled photon pairs over a noisy ground atmosphere of 13km. It is shown that the desired entanglement can still survive after the two entangled photons have passed through the noisy ground atmosphere. This is confirmed by observing a space-like separated violation of Bell inequality of $2.45 \pm 0.09$. On this basis, we exploit the distributed entangled photon source to demonstrate the BB84 quantum cryptography scheme. The distribution distance of entangled photon pairs achieved in the experiment is for the first time well beyond the effective thickness of the aerosphere, hence presenting a significant step towards satellite-based global quantum communication.Comment: 4 pages, 3 figure

MiR–20a-5p promotes radio-resistance by targeting Rab27B in nasopharyngeal cancer cells

Additional file 3: Figure S2. The protein level of PARP and caspase3 detected by western in NCM, 5PM, NCA, 5PA, si-NC and si-Rab27B transfected CNE-2 and CNE-1 cells respectively