Engineering nanoscale roughness on hydrophobic surface : preliminary assessment of fouling behaviour

A preliminary investigation of the fouling behaviour of smooth and roughened superhydrophobic coatings is reported. The effect of nanoscale interfacial roughness on the adhesion of single (SW8) and mixed cultures of micro-foulant for periods of up to 6 months was assessed using visual and wettability measurements. Detailed analysis indicated virtually no micro-organism attached to the superhydrophobic surfaces in the first weeks of immersion. As a result by comparison with smooth substrates, which exhibited fouling within a day, very rough (roughness ratio >2.7) surfaces exhibited high resistance to fouling over a 6-month period. However, after periods exceeding 2 months under ocean conditions, both films showed limited anti-fouling properties. There appears to be a correlation between the nature of the nanoscale roughness in the creation of superhydrophobic coatings and their potential anti-fouling properties. The future architecture of such a correlation is investigated

Quantized control design for impulsive fuzzy networked systems

In this paper, a continuous-time Takagi–Sugeno(T–S) fuzzy system with impulsive effects that are controlled through network is investigated. Network signal-transmission delays and signal-quantization effects are simultaneously considered. The network is with two time-varying additive delays and limited capacity. First, a quantized output-feedback networked control system (NCS) model is established to describe the impulsive NCSs through a channel with limited capacity. Then, based on the Lyapunov–Krasovskii functional approach and a parallel distributed compensation scheme, a delay-dependent stabilization approach is developed for the impulsive NCSs, which guarantees that the closed-loop system is asymptotically stable. Finally, a simulation example is given to illustrate the effectiveness of the proposed method

Distributed average filtering for sensor networks with sensor saturation

This study addresses the distributed average set-membership filtering of spatially varying processes using sensor networks. The system under consideration contains sensor saturation in the presence of unknown-but-bounded process and measurement noise in the sensor network. The so-called distributed average set-membership filtering is defined to quantify bounded consensus regarding the estimation error. A sufficient condition for distributed average set-membership filtering parameter design is established in terms of a set of time-varying linear matrix inequalities. A recursive algorithm is developed for computing the estimator, controller gains and the ellipsoid that guarantees to contain the true state. Simulation results are provided to demonstrate the effectiveness of the proposed method

Observer-based H ∞ control for discrete-time stochastic systems with quantisation and random communication delays

In this study, the authors are concerned with the observer-based quantised H∞ control problem for a class of discrete-time stochastic systems with random communication delays. The system under consideration involves signals quantisation, state dependent disturbance as well as random communication delays. The measured output and the control input quantisation are considered simultaneously by using the sector bound approach, while the random communication delays from the sensor to the controller and from the controller to the plant are modelled by a linear function of the stochastic variable satisfying Bernoulli random binary distribution. It is aimed at designing an observer-based controller such that the dynamics of the closed-loop system is guaranteed to be exponentially stable in the mean square, and a prescribed H∞ disturbance attenuation level is also achieved. Finally, a simulation example is given to illustrate the effectiveness of the proposed method

Abnormal gene expression of proinflammatory cytokines and their receptors in the lymphocytes of patients with bipolar disorder.

Objectives: Abnormalities of protein levels of proinflammatory cytokines and their soluble receptors have been reported in plasma of bipolar (BP) patients. In this study we tested the hypothesis that the mRNA expression of membrane-bound receptors for proinflammatory cytokines will be altered in the lymphocytes of BP patients. Methods: We determined protein and mRNA expression of proinflammatory cytokines, and mRNA expression of their receptors in the lymphocytes from 29 drug-free, hospitalized BP patients and 30 drug-free normal control subjects. The subjects were diagnosed according to DSM-IV criteria. Plasma protein levels of cytokines were determined by ELISA; mRNA levels in lymphocytes were determined by the qPCR method. Results: We found that mean mRNA levels of proinflammatory cytokines IL-1β, IL-6, TNF-α, their receptors, TNFR1, IL-1R1, and the antagonist IL-1RA were significantly higher in the lymphocytes of BP patients compared with normal controls. Conclusions: This study suggests that the observed abnormalities of membrane-bound cytokine receptors may alter the functional response of cytokines in BP illness and that the mRNA levels of these receptors could be a potential biomarker

An engineering route to synthesize stable bulk nanocrystalline magnesium with an average grain size of 20 nm

A simple and effective route to preparing bulk nanocrystalline (NC) pure Mg with an average grain size of 20 nm is first proposed by hydrogenation-disproportionation-desorption-recombination (HDDR) followed by spark plasma sintering (SPS) and hot extrusion (HE) techniques. NC Mg is thermodynamically super-stable against annealing at 550 °C and straining under compression and tension. Moreover, the as-extruded NC Mg samples show high tensile yield stress (TYS) of 259 MPa and compressive yield strength (CYS) of 157 MPa, which are about 2 times and about 7–10 times higher than those of their coarse-grain counterparts and the as-cast samples, respectively

Is there a processing advantage for verb-noun collocations in Chinese reading? Evidence from eye movements during reading

A growing number of studies show a processing advantage for collocations, which are commonly-used juxtapositions of words, such as “joint effort” or “shake hands,” suggesting that skilled readers are keenly perceptive to the occurrence of two words in phrases. With the current research, we report two experiments that used eye movement measures during sentence reading to explore the processing of four-character verb-noun collocations in Chinese, such as 修改文章 (“revise the article”). Experiment 1 compared the processing of these collocations relative to similar four-character expressions that are not collocations (e.g., 修改结尾, “revise the ending”) in neutral contexts and contexts in which the collocation was predictable from the preceding sentence context. Experiment 2 further examined the processing of these four-character collocations, by comparing eye movements for commonly-used “strong” collocations, such as 保护环境 (“protect the environment”), as compared to less commonly-used “weak” collocations, such as 保护自然 (“protect nature”), again in neutral contexts and contexts in which the collocations were highly predictable. The results reveal a processing advantage for both collocations relative to novel expressions, and for “strong” collocations relative to “weak” collocations, which was independent of effects of contextual predictability. We interpret these findings as providing further evidence that readers are highly sensitive to the frequency that words co-occur as a phrase in written language, and that a processing advantage for collocations occurs independently of contextual expectations.</p

Structural heterogeneity of the midcrust adjacent to the central Alpine Fault, New Zealand: Inferences from seismic tomography and seismicity between Harihari and Ross

© 2015. American Geophysical Union. All Rights Reserved. Determining the rates and distributions of microseismicity near major faults at different points in the seismic cycle is a crucial step toward understanding plate boundary seismogenesis. We analyze data from temporary seismic arrays spanning the central section of the Alpine Fault, New Zealand, using double-difference seismic tomography. This portion of the fault last ruptured in a large earthquake in 1717 AD and is now late in its typical 330 year cycle of Mw∼8 earthquakes. Seismicity varies systematically with distance from the Alpine Fault: (1) directly beneath the fault trace, earthquakes are sparse and largely confined to the footwall at depths of 4-11 km; (2) at distances of 0-9 km southeast of the trace, seismicity is similarly sparse and shallower than 8 km; (3) at distances of 9-20 km southeast of the fault trace, earthquakes are much more prevalent and shallower than 7 km. Hypocenter lineations here are subparallel to faults mapped near the Main Divide of the Southern Alps, confirming that those faults are active. The region of enhanced seismicity is associated with the highest topography and a high-velocity tongue doming at 3-5 km depth. The low-seismicity zone adjacent to the Alpine Fault trace is associated with Vp and Vs values at midcrustal depths about 8 and 6% lower than further southeast. We interpret lateral variations in seismicity rate to reflect patterns of horizontal strain rate superimposed on heterogeneous crustal structure, and the variations in seismicity cutoff depth to be controlled by temperature and permeability structure variations. Key Points: Seismicity is sparse near the Alpine Fault late in its typical seismic cycle Seismicity rates increase abruptly 9 km southeast of the fault trace This transition coincides with a strain rate peak and lateral velocity gradient

Zebrafish Embryo Vessel Segmentation Using a Novel Dual ResU-Net model

Zebrafish embryo fluorescent vessel analysis, which aims to automatically investigate the pathogenesis of diseases, has attracted much attention in medical imaging. Zebrafish vessel segmentation is a fairly challenging task, which requires distinguishing foreground and background vessels from the 3D projection images. Recently, there has been a trend to introduce domain knowledge to deep learning algorithms for handling complex environment segmentation problems with accurate achievements. In this paper, a novel dual deep learning framework called Dual ResUNet is developed to conduct zebrafish embryo fluorescent vessel segmentation. To avoid the loss of spatial and identity information, the U-Net model is extended to a dual model with a new residual unit. To achieve stable and robust segmentation performance, our proposed approach merges domain knowledge with a novel contour term and shape constraint. We compare our method qualitatively and quantitatively with several standard segmentation models. Our experimental results show that the proposed method achieves better results than the state-of-art segmentation methods. By investigating the quality of the vessel segmentation, we come to the conclusion that our Dual ResUNet model can learn the characteristic features in those cases where fluorescent protein is deficient or blood vessels are overlapped and achieves robust performance in complicated environments

Dynamic characteristics and reliability analysis of ball screw feed system on a lathe

For ball screw feed system on a lathe, the randomness of geometric parameters deriving from the inevitable manufacturing and assembly errors significantly affected the system dynamic characteristics and turning accuracy. In this study, a novel lumped dynamic model accounting for the analytical piecewise restoring force function involving the overall axial deformation is proposed. The equivalent mechanical model of bearing joints including the change of nominal contact angle is made a reasonable simplification to facilitate acquisition of the system analytical equation of motion. Additionally, the approximate analytical solution of the proposed equation is obtained by the modified Lindstedt–Poincaré method (MLP). The advanced first order second moment method (AFOSM) is employed to evaluate the reliability of dynamic response error. Furthermore, the numerical simulation aims to demonstrate the capabilities of the MLP and AFOSM method in the practical applications. Eventually, the effects of external excitation, sliding platform position, and nominal contact angles on the dynamic response are discussed and the reliability and sensitivity analysis in accordance with actual turning accuracy level is presented