Planning and control of a hybrid vacuum-forming system based on screw-pin tooling

This paper introduced planning and control of a hybrid vacuum-forming machine system (HAVES). The HAVES was developed to integrate CAD/CAM, screw-pin tooling, CNC, vacuum forming and optical measurement device together to produce vacuum forming components. The screw-pin tooling was employed to replace traditional dedicated solid tooling and its reconfigurability provided the HAVES with advantages in rapid producing small batch and mass customization products. The whole control system of the HAVES is divided into two parts: one for screw-pin tooling adjustment and machining by using CNC control, and the other for vacuum forming by using PLC control. The detail design of the control system was discussed

Deeper understanding of cobalt-doped SiC nanowires as excellent electromagnetic wave absorbers

Doping is a facile and effective technique that plays a key role in the function of many semiconductor materials. Unraveling the regulatory mechanism of doping can offer useful guidance for the design of the material structure and fabricating novel functional composites invalid in pure phase structures, which extents their applications in catalysts, light emitting devices, and environmental protection. Especially, transition metal doping related to the spin and charge introduces foreign states to the electronic structures in the host materials and endows the composites with intriguing properties. However, most of the reported papers are limited on the fabrication of the doped composites with enhanced performance. Little progress has been made to clarify the underlying mechanism for those improvements. Herein, Co-doped SiC nanowires with different Co contents were successfully fabricated by a simple carbothermal reduction method. The Co-doped SiC nanowires were characterized in terms of microstructure, electronic structure, and electromagnetic (EM) parameters to study the effects of doping on enhancing the EM wave absorption ability. Both the microstructure analysis and density functional theory calculations indicated that the incorporation of Co into SiC nanowires inhibited the formation of defective structures but increased their conductivity. Thus, the improved electronic transportation ability was dominant in enhancing the dielectric loss. The Co dopants also imparted the Co-doped SiC nanowires with magnetic property, which could generate magnetic resonance to attenuate EM wave and achieve superior impedance matching. The induced synergistic effects between Co dopants and SiC nanowires endowed Co-doped SiC nanowires with excellent EM wave absorption ability. Their minimum reflection loss was -50 dB, and the effective absorption bandwidth was up to 4.0 GHz at 1.5 mm sample thickness. Therefore, the fabricated Co-doped SiC nanowires are potential candidates for high-efficiency EM wave absorption materials. The findings of this research provide a guideline for other doped functional composites. Please click Additional Files below to see the full abstract

Abnormal Spontaneous Brain Activity in Early Parkinson’s Disease With Mild Cognitive Impairment: A Resting-State fMRI Study

Mild cognitive impairment (MCI) is a common symptom at the baseline of early Parkinson’s disease (PD) diagnosis, but the neural mechanism is unclear. To address the issue, the present study employed resting-state functional magnetic resonance imaging data of 19 drug-naïve PD patients with normal cognition (PD-NC), 10 PD patients with MCI (PD-MCI) and 13 age- and gender-matched healthy controls (HC) from the Parkinson’s progression markers initiative (PPMI) (http://www.ppmi-info.org/), and examined abnormal spontaneous brain activities in the PD-MCI. The pattern of spontaneous brain activity was measured by examining the amplitude of low-frequency fluctuations (ALFF) of blood oxygen level dependent signal. Voxel-wise one-way analysis of covariance and post hoc analyses of ALFF were performed under non-parametric permutation tests in a general linear model among the three groups, with age, gender and data center as additional covariates. Statistical significances in the post hoc analysis were corrected by a small volume correction with a cluster-level threshold of p < 0.05 (n = 10000 permutations, FWE-corrected). Correlations of clinical and neuropsychological assessments [i.e., Unified Parkinson’s Disease Rating Scale (UPDRS) total score, Montreal Cognitive Assessment (MoCA) and cognitive domains] with the regional ALFF were performed in the PD-MCI group. Compared with the HC, both PD groups exhibited reduced ALFF in the occipital area (Calcarine_R/Cuneus_R). Specially, the PD-MCI group additionally exhibited increased ALFF in the opercular part of right inferior frontal gyrus (Frontal_Inf_Oper_R). Comparing with the PD-NC, the PD-MCI group exhibited significantly higher ALFF in the Frontal_Inf_Oper_R and left fusiform gyus (ps < 0.05). The correlation analysis revealed that the ALFF in the Frontal_Inf_Oper_R was positively correlated with the UPDRS total score (p < 0.05), but marginally negatively correlated with the MoCA score. For cognitive domains, the ALFF in the region also showed a significantly negative correlation with the score of SF test (p < 0.01) and a marginally negative correlation with the score of Symbol-Digit Modalities Test. Together, we concluded hyperactivity in the right inferior frontal gyrus in early PD with MCI, suggesting a compensatory recruitment in response to cognitive decline, which may shed light on thought of dementia progression and potentially comprehensive treatment in PD

Shadow operator: Effective dynamic load change operation training in air separation processes based on industrial nonlinear MPC and Bloom's taxonomy

A novel human-machine interactive training method for dynamic load change operation in air separation processes (ASPs) is proposed. A shadow operator (SO) is developed in this method to train ASP operators through industrial model predictive control (IMPC) and Bloom's taxonomy. First, a nonlinear two-layer IMPC machine algorithm is developed for dynamic load change operation. The IMPC uses a linear parameter varying prediction model and an iterative multi-step linearization algorithm to compute accurate control decisions. Second, a hierarchical human-machine cooperation model is established to improve the effectiveness of operation training. The model is inspired by an educational psychology framework (Bloom's taxonomy) and assists ASP operators in enhancing their dynamic operational skills. Finally, five dynamic training modes of the SO are designed based on the IMPC algorithm and the human-machine cooperation model. The practical application results demonstrate that the SO improves the effectiveness of skill acquisition for novice operators and the safety of dynamic operations.Comment: 16 pages, 18 figure

Quantitative analysis of the genes affecting development of the hypopharyngeal gland in honey bees (Apis mellifera L.)

Royal jelly has many important biological functions, however the molecular mechanism of royal jelly secretion in hypopharyngeal gland (HG) is still not well understood. In our previously study, six genes (SV2C, eIF-4E, PDK1, IMP, cell growth-regulating nucleolar protein and TGF-βR1) have been shown to might be associated with royal jelly secretion. In this study, the relative expression levels of these genes were examined in the hypopharyngeal gland of workers at different developmental stages (nurse, forager and reversed nurse stages). The results indicated that the relative expression levels of SV2C, eIF-4E, IMP, cell growth-regulating nucleolar protein and TGF-βR1 were reversed at reversed nurse stage compared to forager stage. We concluded that these genes are possibly candidates related to hypopharyngeal gland development or royal jelly secretion

Robot Protection in the Hazardous Environments

Rescue missions for chemical, biological, radiological, nuclear, and explosive (CBRNE) incidents are highly risky and sometimes it is impossible for rescuers to perform, while these accidents vary dramatically in features and protection requirements. The purpose of this chapter is to present several protection approaches for rescue robots in the hazardous conditions. And four types of rescue robots are presented, respectively. First, design factors and challenges of the rescue robots are analyzed and indicated for these accidents. Then the rescue robots with protective modification are presented, respectively, meeting individual hazardous requirements. And finally several tests are conducted to validate the effectiveness of these modified robots. It is clear that these well-designed robots can work efficiently for the CBRNE response activities

Surface Ligand Promotion of Carbon Dioxide Reduction through Stabilizing Chemisorbed Reactive Intermediates

We have explored functionalizing metal catalysts with surface ligands as an approach to facilitate electrochemical carbon dioxide reduction reaction (CO_2RR). To provide a molecular level understanding of the mechanism by which this enhancement occurs, we combine in situ spectroscopy analysis with an interpretation based on quantum mechanics (QM) calculations. We find that a surface ligand can play a critical role in stabilizing the chemisorbed CO_2, which facilitates CO_2 activation and leads to a 0.3 V decrease in the overpotential for carbon monoxide (CO) formation. Moreover, the presence of the surface ligand leads to nearly exclusive CO production. At −0.6 V (versus reversible hydrogen electrode, RHE), CO is the only significant product with a faradic efficiency of 93% and a current density of 1.9 mA cm^(–2). This improvement corresponds to 53-fold enhancement in turnover frequency compared with the Ag nanoparticles (NPs) without surface ligands