The Recovery of Weak Impulsive Signals Based on Stochastic Resonance and Moving Least Squares Fitting

In this paper a stochastic resonance (SR)-based method for recovering weak impulsive signals is developed for quantitative diagnosis of faults in rotating machinery. It was shown in theory that weak impulsive signals follow the mechanism of SR, but the SR produces a nonlinear distortion of the shape of the impulsive signal. To eliminate the distortion a moving least squares fitting method is introduced to reconstruct the signal from the output of the SR process. This proposed method is verified by comparing its detection results with that of a morphological filter based on both simulated and experimental signals. The experimental results show that the background noise is suppressed effectively and the key features of impulsive signals are reconstructed with a good degree of accuracy, which leads to an accurate diagnosis of faults in roller bearings in a run-to failure test

Response characteristics of the DeepCwind floating wind turbine moored by a Single-Point Mooring system

In recent years, the SPM (Single-Point Mooring) concept has been widely employed in several branches of the naval architecture and marine engineering field, such as FPSOs (Floating Production, Storage and Offloading units), offshore oil rigs, etc., but not yet popular in the offshore wind energy. To investigate the response characteristics of an SPM-moored FWT (Floating Wind Turbine), in the present work, we perform a numerical study on the DeepCwind semisubmersible wind turbine, using the state-of-the-art open-source tool FAST. The free-decay test results show that the SPM layout affects the natural periods of the wind turbine in rotational modes, as well as the mooring stiffness of the diagonal rotational and crossing rotational-translational terms, especially in relation to the yaw mode. Comparisons of the RAOs (Response Amplitude Operators) elucidate that the presence of wind influences significantly the sway, roll and yaw motions of the SPM layout. Finally, the weathervane test shows that an asymmetry exists in the free-yaw motion response when the semisubmersible wind turbine is moored by an SPM system

Three-dimensional carbon-based anodes promoted the accumulation of exoelectrogens in bioelectrochemical systems.

To achieve deep understandings on the effects of structure and surface properties of anode material on the performance of bioelectrochemical systems, the present research investigated the bacterial community structures of biofilms attached to different three-dimensional anodes including carbon felt and materials derived from pomelo peel, kenaf stem, and cardboard with 454 pyrosequencing analysis based on the bacterial 16S rRNA gene. The results showed that bacterial community structures, especially the relative abundance of exoelectrogens, were significantly related to the types of adopted three-dimensional anode materials. Proteobacteria was the shared predominant phylum, accounting for 55.4%, 52.1%, 66.7%, and 56.1% for carbon felt, cardboard, pomelo peel, and kenaf stem carbon, respectively. The most abundant OTU was phylogenetically related to the well-known exoelectrogen of Geobacter, with a relative abundance of 16.3%, 19.0%, 36.3%, and 28.6% in carbon felt, cardboard, pomelo peel, and kenaf stem, respectively. Moreover, another exoelectrogen of Pseudomonas sp. accounted for 4.9% in kenaf stem and 3.9% in carbonboard, respectively. The results implied the macrostructure and properties of different anode materials might result in different niches such as hydrodynamics and substrate transport dynamics, leading to different bacterial structure, especially different relative abundance of exoelectrogens, which consequently affected the performance of bioelectrochemical systems. PRACTITIONER POINTS: Bioelectrochemical systems (BESs) represent a novel biotechnology platform to simultaneously treat wastewaters and produce electrical power. Three-dimensional materials derived from nature plant as anode to promote electricity output from BESs and reduce the construct cost of BESs. Macrostructure of the three-dimensional anode material affected phylotype richness and phylogenetic diversity of microorganisms in anodic biofilm of BESs. Geobacter as well-known exoelectrogen was the most abundant in biofilm attached to three-dimensional anode

In silico screening of potentially bioactive-anti-functional dyspepsia constituents of Magnoliae officinalis Cortex based on molecular docking and network pharmacology

Purpose: To screen for bioactive anti-functional dyspepsia compounds from Magnoliae officinalis Cortex (Hou Po) and to identify the mechanism(s) of action involved.Methods: The compounds of Hou Po were collected from the literature. The related target proteins were identified from DrugBank. Through  “Libdock” module of Discovery Studio 3.5, the compounds were matched with related target proteins. Taking the Libdock score of the original ligand with target protein as standard, components with higher scores than this standard were considered as potential bioactive compounds. Based on Cytoscape software, the interaction networks of the bioactive compound-target protein complexes were mapped. On the other hand, the online DAVID database was used to analyze the GO enrichment and KEGG pathway of each target.Results: A total of 199 chemical constituents and 13 correlated target proteins were obtained. One hundred and thirty-nine (139) potential bioactive constituents were acquired based on molecular docking. Thirty-one (31) bioactive compounds were selected based on degree values in networkanalysis. “Palmitone” and “magnolignan G” which had the highest degree values were considered promising and leading compounds. The result of gene enrichment analysis showed that the bioactive compounds exerted their effects mainly via “neuroactive ligand-receptor interaction” pathway and “Cholinergic synapse” pathways.Conclusion: Based on molecular docking and network pharmacology technique, the material basis for the use of Hou Po in the treatment of FD has been revealed. This finding provides a useful guide in the development of Hou Po-based anti-FD drugs. Keywords: Magnolia officinalis, Hou Po, Molecular docking, Functional dyspepsia, Network pharmacolog

A wearable fiber-optic sensor for monitoring human elbow and wrist joint motion

This article describes a wearable sensor for monitoring the motion of human elbow and wrist joints. The sensor converts the joint motion angle into a displacement, which is monitored using a fiber-optic sensor based on reflective light intensity modulation. A mathematical model is established, and the potential influencing factors of the sensor are investigated. Two prototypes for elbow and wrist joint angle monitoring are fabricated and validated. The experimental results indicate that the proposed sensor has a measurement range of 0–60° (0–120°), with a resolution of 0.338° (3.6°) for monitoring the wrist joint palm flexion (elbow joint flexion). The proposed sensor has the potential to be used for rehabilitation purposes and monitoring of joint angles while performing reaching tasks, which are the most common upper-limb gestures

Transcriptome analysis of stem development in the tumourous stem mustard Brassica juncea var. tumida Tsen et Lee by RNA sequencing

<p>Abstract</p> <p>Background</p> <p>Tumourous stem mustard (<it>Brassica juncea </it>var. <it>tumida </it>Tsen et Lee) is an economically and nutritionally important vegetable crop of the <it>Cruciferae </it>family that also provides the raw material for <it>Fuling </it>mustard. The genetics breeding, physiology, biochemistry and classification of mustards have been extensively studied, but little information is available on tumourous stem mustard at the molecular level. To gain greater insight into the molecular mechanisms underlying stem swelling in this vegetable and to provide additional information for molecular research and breeding, we sequenced the transcriptome of tumourous stem mustard at various stem developmental stages and compared it with that of a mutant variety lacking swollen stems.</p> <p>Results</p> <p>Using Illumina short-read technology with a tag-based digital gene expression (DGE) system, we performed <it>de novo </it>transcriptome assembly and gene expression analysis. In our analysis, we assembled genetic information for tumourous stem mustard at various stem developmental stages. In addition, we constructed five DGE libraries, which covered the strains <it>Yong'an </it>and <it>Dayejie </it>at various development stages. Illumina sequencing identified 146,265 unigenes, including 11,245 clusters and 135,020 singletons. The unigenes were subjected to a BLAST search and annotated using the GO and KO databases. We also compared the gene expression profiles of three swollen stem samples with those of two non-swollen stem samples. A total of 1,042 genes with significantly different expression levels occurring simultaneously in the six comparison groups were screened out. Finally, the altered expression levels of a number of randomly selected genes were confirmed by quantitative real-time PCR.</p> <p>Conclusions</p> <p>Our data provide comprehensive gene expression information at the transcriptional level and the first insight into the understanding of the molecular mechanisms and regulatory pathways of stem swelling and development in this plant, and will help define new mechanisms of stem development in non-model plant organisms.</p

An Attention-Controlled Hand Exoskeleton for the Rehabilitation of Finger Extension and Flexion Using a Rigid-Soft Combined Mechanism

Hand rehabilitation exoskeletons are in need of improving key features such as simplicity, compactness, bi-directional actuation, low cost, portability, safe human-robotic interaction, and intuitive control. This article presents a brain-controlled hand exoskeleton based on a multi-segment mechanism driven by a steel spring. Active rehabilitation training is realized using a threshold of the attention value measured by an electroencephalography (EEG) sensor as a brain-controlled switch for the hand exoskeleton. We present a prototype implementation of this rigid-soft combined multi-segment mechanism with active training and provide a preliminary evaluation. The experimental results showed that the proposed mechanism could generate enough range of motion with a single input by distributing an actuated linear motion into the rotational motions of finger joints during finger flexion/extension. The average attention value in the experiment of concentration with visual guidance was significantly higher than that in the experiment without visual guidance. The feasibility of the attention-based control with visual guidance was proven with an overall exoskeleton actuation success rate of 95.54% (14 human subjects). In the exoskeleton actuation experiment using the general threshold, it performed just as good as using the customized thresholds; therefore, a general threshold of the attention value can be set for a certain group of users in hand exoskeleton activation

Life history traits of low-toxicity alternative bisphenol S on Daphnia magna with short breeding cycles : A multigenerational study

Due to relatively lower toxicity, bisphenol S (BPS) has become an alternative to previously used bisphenol A. Nevertheless, the occurrence of BPS and its ecological impact have recently attracted increasing attentions because the toxicology effect of BPS with life cycle or multigenerational exposure on aquatic organisms remains questionable. Herein, Daphnia magna (D. magna) multigenerational bioassays spanning four generations (F0–F3) and single-generation recovery (F1 and F3) in clean water were used to investigate the ecotoxicology of variable chronic BPS exposure. For both assays, four kinds of life-history traits (i.e., survival, reproduction, growth and ecological behavior) were examined for each generation. After an 18-day exposure under concentration of 200 μg/L, the survival rate of D. magna was less than 15 % for the F2 generation, whereas all died for the F3 generation. With continuous exposure of four generations of D. magna at environmentally relevant concentrations of BPS (2 μg/L), inhibition of growth and development, prolonged sexual maturity, decreased offspring production and decreased swimming activity were observed for the F3 generation. In particular, it is difficult for D. magna to return to its normal level through a single-generation recovery in clean water in terms of reproductive function, ecological behavior and population health. Hence, multi-generational exposure to low concentrations of BPS can have adverse effects on population health of aquatic organisms with short breeding cycles, highlighting the necessity to assess the ecotoxicology of chronic BPS exposure for public health.publishedVersionPeer reviewe

Design and performance characterization of a soft robot hand with fingertip haptic feedback for teleoperation

A soft robot hand with fingertip haptic feedback for teleoperation is proposed to perform complex tasks and ensure safe and friendly human-machine interaction. This robot hand can perform finger flexion/extension and abduction/adduction motions. A data glove is used to collect the hand joint angle data of the operator. Flexion sensors are embedded in the soft robot hand to monitor the bending angles of the actuators. Pressure sensors on the fingertips of the robot hand collect contact force data, and haptic feedback actuators located on the fingertips of the operator display the contact force to the operator. Characterization tests and teleoperation performance tests involving human participants are performed to prove the feasibility of the soft robot hand. The soft robot hand prototype satisfies the output force requirements and can meet 96.86% of the design requirements of the joint angles. The soft robot hand can be teleoperated to perform nine commonly used motions in daily operational tasks. The success rates of fingertip force discrimination, grasp, and pinch ability experiment are 100%, 95.00%, and 98.33%, respectively. The results of the experiment suggest that the soft robot hand with fingertip haptic feedback can perform complex tasks in teleoperation

Inhibition effect of polyvinyl butyral on crystallization of polypropylene

In this work, a series of polypropylene/polyvinyl butyral (PP/PVB) blends were prepared by melt-blending process, at PVB loadings 3 wt%, 10 wt%, and 30 wt%. The effects of PVB on crystallization behavior of PP were investigated by differential scanning calorimetry (DSC), and polarized optical microscopy (POM). The isothermal crystallization kinetics were analyzed by Avrami equations. It was found that the addition of PVB strikingly reduced the overall crystallization rate of PP. The POM results further indicated that the crystallization rate of PP/PVB was significantly reduced by reducing the nucleation density of PP with the addition of PVB. The fractured surface morphology of PP/PVB blends was characterized by scanning electron microscopy (SEM), and the results showed that the PVB was uniformly dispersed in the PP matrix as small spherical particles, with a good dispersion and dimensional stability