Bioinspired Coordinated Path Following for Vessels with Speed Saturation Based on Virtual Leader

This paper investigates the coordinated path following of multiple marine vessels with speed saturation. Based on virtual leader strategy, the authors show how the neural dynamic model and passivity-based techniques are brought together to yield a distributed control strategy. The desired path following is achieved by means of a virtual dynamic leader, whose controller is designed based on the biological neural shunting model. Utilizing the characteristic of bounded and smooth output of neural dynamic model, the tracking error jump is avoided and speed saturation problem is solved in straight path. Meanwhile, the coordinated path following of multiple vessels with a desired spatial formation is achieved through defining the formation reference point. The consensus of formation reference point is realized by using the synchronization controller based on passivity. Finally, simulation results validate the effectiveness of the proposed coordinated algorithm

Study on Self-crosslinking of Hydrogen Peroxide Oxidating Collagen

Content: The utilization of mink waste generated through the industrial process attracted both industry and academia interests. In this study, the use of hydrogen peroxide as an oxidizing agent onto collagen producing self-crosslinking which extracting from mink solid waste was studied by infrared spectrum, fluorescence spectrum and thermal properties. The effect of hydrogen peroxide dosage and reaction temperature on the degree of oxidative self-crosslinking of collagen was analyzed by the changes of molecular structure and thermal stability. It was found that, hydroxide groups on the collagen side-chains can be oxidized to aldehyde groups and carboxyl groups by hydrogen peroxide in alkaline environment. These oxidized groups can crosslink with functional groups on collagen by covalent bond and ionic bond, changing collagen molecular structure and improving thermal stability. When the dosage of hydrogen peroxide was 14.74% and reaction temperature was 40℃ ±, the oxidative self-crosslinking of collagen was the strongest. This study provided theoretical basis for the high-value utilization of mink wastes. Take-Away: 1. The oxidative self-crosslink of collagen extracted mink solid waste was studied. 2. Hydrogen peroxide was applied as environment friendly oxidant. 3. The change of functional groups and degree of crosslinks during the oxidation was studied via infrared, fluorescence spectrum and differential scanning calorimetry

A comprehensive review on shale studies with emphasis on nuclear magnetic resonance (NMR) technique

Multi-scale shale studies put a significant emphasis on high-resolution investigations from nanometer to decametre scales. Despite that multiple advanced techniques have been used in shale studies, they are mostly limited to the detection scopes and have restricted capacity for high-resolution characterization of shale nanopores with substantial heterogeneity. Therefore, it remains a challenge for accurate resource estimation in unconventional shales. The nuclear magnetic resonance (NMR) is an advanced technique enabling non-destructive and fast measurements, and has the advantage of high-resolution evaluation of shale formations and nanopore structure. Petrophysical studies using NMR have made breakthroughs in shale studies. However, multi-scale shale investigations with emphasis on NMR technique have not been fully reviewed. This paper thus provides an overview of the capabilities of NMR in multidisciplinary shale studies to largely improve accuracy in unconventional resource estimations. We proposed a multi-scale and quantitative NMR detection method for accurate characterization of the nanopore structure and fast relaxation fluids. The laboratory NMR core analysis and NMR well logging can be applied for the detection from nanometer to decametre scales, respectively, and precisely measure shale reservoir properties, including total/effective porosities, clay-bound water (CBW) contents, pore size distribution, surface relaxivity, absolute permeability, wettability, and fluid types. Importantly, with NMR application, new research areas such as the integrated supercritical CO2 enhanced shale gas recovery (scCO2-ESGR) and carbon geo-sequestration, and the advanced underground hydrogen storage (UHS) in shales can be developed to achieve the target of long-term energy supply and net-zero carbon emission. New techniques such as in-situ kerogen pyrolysis are also improved by using NMR dynamic monitoring

Finite-Time Tracking Control for a Class of MIMO Nonlinear Systems with Unknown Asymmetric Saturations

This paper addresses the problem of finite-time tracking control for multiple-input and multiple-output (MIMO) nonlinear systems with asymmetric saturations. A systematic approach is proposed to eliminate the effects of unmeasured external disturbances and unknown asymmetric saturations. In the proposed control strategy, a terminal sliding mode disturbance observer is provided to estimate the augmented disturbance (which contains the unknown asymmetric input saturation and external disturbance). The approximation error of the augmented disturbance can converge to zero in a fixed finite-time interval. Furthermore, a novel finite-time tracking control algorithm is developed to guarantee fast convergence of the tracking error. Compared with the existing results on finite-time tracking control, the chattering problem and the input saturation problem can be solved in a unified framework. Several simulations are given to demonstrate the effectiveness of the proposed approach

Learning Data-Driven Vector-Quantized Degradation Model for Animation Video Super-Resolution

Existing real-world video super-resolution (VSR) methods focus on designing a general degradation pipeline for open-domain videos while ignoring data intrinsic characteristics which strongly limit their performance when applying to some specific domains (eg., animation videos). In this paper, we thoroughly explore the characteristics of animation videos and leverage the rich priors in real-world animation data for a more practical animation VSR model. In particular, we propose a multi-scale Vector-Quantized Degradation model for animation video Super-Resolution (VQD-SR) to decompose the local details from global structures and transfer the degradation priors in real-world animation videos to a learned vector-quantized codebook for degradation modeling. A rich-content Real Animation Low-quality (RAL) video dataset is collected for extracting the priors. We further propose a data enhancement strategy for high-resolution (HR) training videos based on our observation that existing HR videos are mostly collected from the Web which contains conspicuous compression artifacts. The proposed strategy is valid to lift the upper bound of animation VSR performance, regardless of the specific VSR model. Experimental results demonstrate the superiority of the proposed VQD-SR over state-of-the-art methods, through extensive quantitative and qualitative evaluations of the latest animation video super-resolution benchmark. The code and pre-trained models can be downloaded at https://github.com/researchmm/VQD-SR

New ages for the Upper Palaeolithic site of Xibaimaying in the Nihewan Basin, northern China: implications for small-tool and microblade industries in north-east Asia during Marine Isotope Stages 2 and 3

It has been suggested that the \u27small-tool\u27 and microblade Upper Palaeolithic industries coexisted in the Nihewan Basin of northern China for about 8-14 000 years during Marine Isotope Stage (MIS) 2. This inference was based on uranium-series ages of around 15 and 18 ka for bovid teeth recovered from the \u27latest\u27 small-tool site of Xibaimaying - the youngest occurrence of such tools in the region - and optically stimulated luminescence (OSL) dating of the earliest typical microblade site (Youfang: ∼26-29 ka). In this study, we re-dated the Xibaimaying site using single-grain OSL methods and the resulting ages indicate that the cultural layer was deposited 46 ± 3 ka ago, during MIS 3 - more than 20 millennia earlier than previously thought and older also than the so-called earliest \u27primitive\u27 and typical microblade tools found at Zhiyu (∼31-39 ka cal BP) and Youfang. These new ages for human occupation of Xibaimaying remove support for the parallel development of the small-tool and microblade industries in the Nihewan Basin during the Upper Palaeolithic, but reliable age estimates from additional sites are needed to confidently infer the nature of the chronological relationship between these two Upper Palaeolithic industries and the associated toolmakers

Dimensional Changes in the Skulls of Ancient Children with Age in Xinjiang, China

Many scholars have conducted research on the growth patterns of children’s skulls in terms of skull size, head circumference, cranial cavity volume, and so forth. This study compared and analyzed 20 skull measurement indexes of different ages from 38 children’s skulls (aged 2–15) and 87 adult female skulls (aged 20–40) at the Zaghunluq cemetery in Xinjiang, China, in an attempt to figure out how the size Children’s of ancient children’s skulls changed with age. Analysis of variance (ANOVA) showed that there were significant differences between the six age groups (2 years, 3–5 years, 6–8 years, 9–11 years, 12–15 years, and adults) in terms of metrical cranial traits, cranial area, and cranial cavity volume. The study indicated that the skull kept growing from ages 3 to 5, 12 to 15, and 15 to adulthood, implying that the skull sizes of ancient children in Xinjiang continued to increase with age. In addition, the study revealed that children aged 12 to 15 had skulls that were significantly smaller than those of adults. This finding showed that the skulls of ancient children in Xinjiang were not fully developed at the age of 15. It is also important to note that differences existed between age groups in both the developmental traits of the cranium and the rate at which the skull changes