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The proliferation of intelligent, connected Internet of Things (IoT) devices facilitates data collection. However, task workers may be reluctant to participate in data collection due to privacy concerns, and task requesters may be concerned about the validity of the collected data. Hence, it is vital to evaluate the quality of the data collected by the task workers while protecting privacy in spatial crowdsourcing (SC) data collection tasks with IoT. To this end, this paper proposes a privacy-preserving data reliability evaluation for SC in IoT, named PARE. First, we design a data uploading format using blockchain and Paillier homomorphic cryptosystem, providing unchangeable and traceable data while overcoming privacy concerns. Secondly, based on the uploaded data, we propose a method to determine the approximate correct value region without knowing the exact value. Finally, we offer a data filtering mechanism based on the Paillier cryptosystem using this value region. The evaluation and analysis results show that PARE outperforms the existing solution in terms of performance and privacy protection. [ABSTRACT FROM AUTHOR]

In this study, we successfully produced Fe-based amorphous composite coatings on the surface of 45 steel using laser cladding technology, and the impact of the relative content of Cr and Mo elements on the microstructure, hardness, and wear resistance of composite coatings has been investigated. The results show that the microstructure of the coating changes from dendrite to amorphous nanocrystalline when the content of Cr and Mo is 20 and 15 wt. %, respectively. However, when the Mo element continues to be added, elemental segregation will be caused, resulting in a large number of brittle Fe–Cr–Mo intermetallic compounds and MoSi2 ceramic phases in the coating. Therefore, the appropriate element ratio can not only increase the amorphous phase content in the coating but also prevent elemental segregation. Among the three types of amorphous composite coatings studied, the Fe45Cr20Mo15B10Si10 (wt. %) composite coating exhibited the most favorable performance, primarily due to its highest amorphous content (43.33%). Through the interaction of the amorphous phase, α-Fe, Fe–Cr solid solution, and a small proportion of intermetallic compounds, this coating achieved a hardness of 1282.8 HV0.2, approximately five times that of the 45 steel substrate, and demonstrated superior wear resistance. [ABSTRACT FROM AUTHOR]

The rapid development of the power industry has resulted in a significant amount of electric porcelain solid waste. To address the challenges of small‐scale utilization and low added value associated with the current utilization of porcelain solid waste, a new high‐temperature resistant material was successfully developed using waste electric porcelain with varying particle sizes as the primary raw material. The dependence of composition, structure, and mechanical properties on fine particle size and sintering temperature was explored. The research has determined that the most effective particle size for the synthesis of refractory materials using waste electric porcelain is 120 mesh, and the optimal temperature is 1600°C. When the temperature exceeds 1500°C, the expansion generated by the decomposition of sillimanite will counteract the shrinkage of the liquid phase reaction, thereby maintaining the morphology of the sample. This process forms a unique interwoven mullite morphology through the decomposition of sillimanite, thereby enhancing the strength of the material. As a result, the optimal bending strength of 74 MPa and the optimal compression strength of 207 MPa were obtained. The realization of high‐temperature resistant materials based on discarded electric porcelain has shown foreseeable potential in large‐scale high‐value utilization. [ABSTRACT FROM AUTHOR]