Energy optimal control of servo-pneumatic cylinders through nonlinear static feedback linearization

Although pneumatic actuators are widely used in industry, they have two major weaknesses-nonlinearities associated with compressibility of air and low energy efficiency. The former limits its applicability whenever accurate positioning is required, and the latter has a negative impact on users through increased energy costs. This paper addresses these issues with the aim of developing a widely applicable servo control strategy, which combines improved tracking accuracy and energy efficiency. A detailed actuator system model is linearized through nonlinear input-output feedback linearization, and the energy optimal velocity profile is derived. Simulation and experimental studies indicate that energy efficiency improvements of 3-7 are possible, while tracking accuracy can be ensured. The method is suitable for real-time implementation and is cost effective; it requires the implementation of an improved velocity profile, while hardware components do not need to be altered. © 2012 American Society of Mechanical Engineers.</p

Quantitative structure-property relationship modelling on autoignition temperature: evaluation and comparative analysis

The autoignition temperature (AIT) serves as a crucial indicator for assessing the potential hazards associated with a chemical substance. In order to gain deeper insights into model performance and facilitate the establishment of effective methodological practices for AIT predictions, this study conducts a benchmark investigation on Quantitative Structure-Property Relationship (QSPR) modelling for AIT. As novelties of this work, three significant advancements are implemented in the AIT modelling process, including explicit consideration of data quality, utilization of state-of-the-art feature engineering workflows, and the innovative application of graph-based deep learning techniques, which are employed for the first time in AIT prediction. Specifically, three traditional QSPR models (multi-linear regression, support vector regression, and artificial neural networks) are evaluated, alongside the assessment of a deep-learning model employing message passing neural network architecture supplemented by graph-data augmentation techniques.</p

Data_Sheet_1_Generation of Individual Whole-Brain Atlases With Resting-State fMRI Data Using Simultaneous Graph Computation and Parcellation.PDF

<p>The human brain can be characterized as functional networks. Therefore, it is important to subdivide the brain appropriately in order to construct reliable networks. Resting-state functional connectivity-based parcellation is a commonly used technique to fulfill this goal. Here we propose a novel individual subject-level parcellation approach based on whole-brain resting-state functional magnetic resonance imaging (fMRI) data. We first used a supervoxel method known as simple linear iterative clustering directly on resting-state fMRI time series to generate supervoxels, and then combined similar supervoxels to generate clusters using a clustering method known as graph-without-cut (GWC). The GWC approach incorporates spatial information and multiple features of the supervoxels by energy minimization, simultaneously yielding an optimal graph and brain parcellation. Meanwhile, it theoretically guarantees that the actual cluster number is exactly equal to the initialized cluster number. By comparing the results of the GWC approach and those of the random GWC approach, we demonstrated that GWC does not rely heavily on spatial structures, thus avoiding the challenges encountered in some previous whole-brain parcellation approaches. In addition, by comparing the GWC approach to two competing approaches, we showed that GWC achieved better parcellation performances in terms of different evaluation metrics. The proposed approach can be used to generate individualized brain atlases for applications related to cognition, development, aging, disease, personalized medicine, etc. The major source codes of this study have been made publicly available at https://github.com/yuzhounh/GWC.</p

Coherent Twinning Phenomena: Towards Twinning Superlattices in III−V Semiconducting Nanowires

We report evidence in GaP and InP nanowires for a coherent modulation of the structure along the wire axis. By using electron diffraction, we have observed an additional series of diffraction peaks consistent with a quasiperiodic placement of twinning boundaries along the wire. This observation is indeed unexpected, as the vapor−liquid−solid growth conditions used to produce the nanowires were not modulated. The averaged repeat distance of the structure, i.e., the distance between twin boundaries, has been found to depend on the temperature gradient imposed in the growth zone. Future control of the twinning superlattice period should allow significant design possibilities for electronic, thermoelectric, thermal and electro-optic applications of semiconducting nanowires

Design of high entropy alloys based on the experience from commercial superalloys

<div><p>High entropy alloys (HEAs) have been drawing increasing attention recently and gratifying results have been obtained. However, the existing metallurgic rules of HEAs could not provide specific information of selecting candidate alloys for structural applications. Our brief survey reveals that many commercial superalloys have medium and even to high configurational entropies. The experience of commercial superalloys provides a clue for helping us in the development of HEAs for structural applications.</p></div

Ultrafast Nanocrystals Decorated Micromotors for On-Site Dynamic Chemical Processes

CdS-polyaniline-Pt and ZnS-polyaniline-Pt micromotors have been synthesized and characterized. The nanocrystals are generated “in situ” during the template electrosynthesis of the micromotors while being simultaneously trapped in the polymeric network, generating a hybrid structure. The presence of nanocrystal “edges” in the inner polyaniline layer result in a rough Pt catalytic surface and enhanced electron transfer for highly efficient bubble propulsion at remarkable speeds of over 2500 μm/s. The incorporation of CdS and ZnS nanocrystals impart several attractive functions, including cation-exchange based chemical transformation capabilities and enhanced photocatalytic performance. The remarkable ion-exchange properties of ZnS-polyaniline (PANI)-Pt micromotors are illustrated for the cation exchange of heavy metals cations. The superior photocatalytic performance of CdS-PANI-Pt micromotors is used for the enhanced photocatalytic oxidation of bisphenol A. Such self-propelled micromotors act as highly efficient dynamic platforms that offer significantly shorter and more efficient processes as compared with common static operations. The attractive properties of these micromotors will pave the way for diverse sensing, decontamination, energy generation, or electronic applications

sj-docx-1-jdr-10.1177_00220345231207309 – Supplemental material for ASH2L, Core Subunit of H3K4 Methylation Complex, Regulates Amelogenesis

Supplemental material, sj-docx-1-jdr-10.1177_00220345231207309 for ASH2L, Core Subunit of H3K4 Methylation Complex, Regulates Amelogenesis by X. Zhu, Z. Ma, F. Xie and J. Wang in Journal of Dental Research</p

Ultrafast Nanocrystals Decorated Micromotors for On-Site Dynamic Chemical Processes

CdS-polyaniline-Pt and ZnS-polyaniline-Pt micromotors have been synthesized and characterized. The nanocrystals are generated “in situ” during the template electrosynthesis of the micromotors while being simultaneously trapped in the polymeric network, generating a hybrid structure. The presence of nanocrystal “edges” in the inner polyaniline layer result in a rough Pt catalytic surface and enhanced electron transfer for highly efficient bubble propulsion at remarkable speeds of over 2500 μm/s. The incorporation of CdS and ZnS nanocrystals impart several attractive functions, including cation-exchange based chemical transformation capabilities and enhanced photocatalytic performance. The remarkable ion-exchange properties of ZnS-polyaniline (PANI)-Pt micromotors are illustrated for the cation exchange of heavy metals cations. The superior photocatalytic performance of CdS-PANI-Pt micromotors is used for the enhanced photocatalytic oxidation of bisphenol A. Such self-propelled micromotors act as highly efficient dynamic platforms that offer significantly shorter and more efficient processes as compared with common static operations. The attractive properties of these micromotors will pave the way for diverse sensing, decontamination, energy generation, or electronic applications

The influence of meteorological variation on the upwelling system off eastern Hainan

No abstracts are to be cited without prior reference to the author.The influence of meteorological variation (i.e. typhoon and precipitation events) on the coastal upwelling off eastern Hainan Island was studied based on observations taken during two upwelling seasons. The observations were made in August 2007 and July 2008. We found that, in principle, similar structure of sea surface temperature and bottom temperature prevailed in both observational periods, providing evidence that upwelling events occur frequently during the summer monsoon along the eastern Hainan shelf. Based on a simple momentum balance theory, we studied the balances between momentum fluxes, windstress, and bottom stress. The results demonstrated that the Burger number S ≈ 1, indicating that the cross‐shelf momentum flux divergence was balanced by the windstress and the onshore return flow occurred in the interior of the water column. Hence, a conceptual model of the upwelling structure was built for further understanding of upwelling events. In addition, it was also observed that variations in the strength of upwelling are controlled by storm events (i.e. strong northerly winds change the structure of the thermocline on the shelf significantly). The strong mixing caused by wind reduces the strength of the thermocline, in particular in coastal seas. Based on our conceptual model, a frontal zone between mixed coastal water and offshore water develops which destabilizes the water column and hence decreases the upwelling strength. Freshwater from the two main rivers in Wenchang Bay are confined to the coastal area less than 20–30 m deep, as confirmed by our water mass analysis. Freshwater discharge stabilized the water column, inhibiting the upwelling as revealed by the potential energy calculation. Consequently, estuarine water only inhibits the upwelling in the near coastal area. Therefore, it can be concluded that estuarine water does not have a significant impact on upwelling strength on the shelf