Design of Twin Builder-Based Digital Twin Online Monitoring System for Crane Girders.

The crossbeam is frequently subjected to alternating loads during work as an essential load-bearing part of the crane. However, due to the large volume and the limitations of detection technology, it is impossible to realize online monitoring of the mechanical state. The ongoing advancement of ROMing and digital twin technology plays a pivotal role in facilitating the resolution of this particular issue. In this paper, we take the crane beam as the physical entity and combine the Twin Builder reduced-order technology and Deployer digital twin deployment technology to establish a digital twin of the beam. The load recognition model within the twin system exhibits a prediction error rate of ±5%. Furthermore, the accuracy of the ROM surpasses that of conventional machine learning models by a factor of 25. Upon deployment on the web platform, the results are delivered within 0.5 s, representing a substantial improvement as it is merely 1/15 of the time required for traditional 3D displays. The digital twin online monitoring system has the advantages of high accuracy and low requirements for monitoring equipment, which can be widely used in engineering practice to solve the problem that the mechanical state of large parts cannot be accurately monitored online.

On Connected Target k-Coverage in Heterogeneous Wireless Sensor Networks.

Coverage and connectivity are two important performance evaluation indices for wireless sensor networks (WSNs). In this paper, we focus on the connected target k-coverage (CTC k) problem in heterogeneous wireless sensor networks (HWSNs). A centralized connected target k-coverage algorithm (CCTC k) and a distributed connected target k-coverage algorithm (DCTC k) are proposed so as to generate connected cover sets for energy-efficient connectivity and coverage maintenance. To be specific, our proposed algorithms aim at achieving minimum connected target k-coverage, where each target in the monitored region is covered by at least k active sensor nodes. In addition, these two algorithms strive to minimize the total number of active sensor nodes and guarantee that each sensor node is connected to a sink, such that the sensed data can be forwarded to the sink. Our theoretical analysis and simulation results show that our proposed algorithms outperform a state-of-art connected k-coverage protocol for HWSNs.

[Interaction between polyamide and zinc salt].

X-ray diffraction and FTIR spectroscopic method have been used to investigate the interaction between the amide group of nylon 6 and zinc chloride. The nylon sample obtained by adding formic acid solution of nylon into aqueous solution saturated by zinc chloride is significantly different from the nylon precipitated after mixing formic acid solution of nylon and water. X-ray diffraction results demonstrate that nylon precipitated from water has crystallization while the sample acquired from saturated solution of ZnCl2 remains amorphous. FTIR spectroscopic study shows that the interaction between zinc ion and the amide group of nylon 6 brings about significant variation of amide I and II bands and prevents the crystallization of nylon. The interaction between nylon and zinc ions may be helpful in the development of a new method of manufacturing new nylon material with superior performance.

[Study on the photofluorescence of Eu(III) and long chain fatty acid complexes].

The complexes having the compositions of Eu(L1)(3)2H2O,Eu(L1)3phen,Eu(L2)(3)2H2O,Eu(L2)3phen (phen = 1,10-phenathroline,L1 = Dodecanoic acid, L2 = Stearic acid) were synthesized and characterized by elemental analysis and FTIR spectra. Their fluorescence spectra, UV spectra and TEM (Transmission Electron Microscope) have been investigated. The results show that the 5D0-7F1 and 5D0-7F2 transition of Eu(III) are observed in the emission spectrum of the particles at room temperature. As good photoluminescent materials, they may be useful in the regions of EL (Electroluminescence) or macromolecule composite materials doped with rare earth.