Performance Research and Formulation Optimization of High-Performance Local Insulation Spray Coating Materials

Bird pest control has become a major task for the operation and maintenance of distribution network lines. Epoxy resin that cures quickly at room temperature can be used to coat locations where birds frequently build their nests. However, epoxy resin has enormous internal stress and is brittle, so it is essential to toughen it. In this paper, for a room temperature curing system composed of polyurethane-modified epoxy resin and a polythiol curing agent, three kinds of particles, i.e., Al₂O₃, SiO₂, and Mg(OH)₂, were used to modify a polyurethane modified epoxy resin. Orthogonal experiments were designed to study the effects of different fillers on the comprehensive properties of polyurethane-modified epoxy resins. The experimental results showed that there were not only independent effects of different kinds if particles on the resin, but also synergistic effects of multiple particles. Nanoparticles can reduce the defects introduced by microparticles to a certain extent and improve the mechanical and electrical properties of the resin. The overall performance of the resin was optimized when the amounts of SiO₂, Al₂O₃, and Mg(OH)₂ were 1.7%, 2.5%, and 7%, respectively. The tensile strength of the resin was increased by 70%, the elongation at a break by 67.53%, and the breakdown strength by 20.31% compared with before the addition of filler. The microscopic morphology and thermal properties of the resin before and after the addition of filler were also studied. Adding fillers caused more cracks to absorb part of the energy when the resin matrix was stressed and increased the rigidity of the resin matrix and the resin's glass transition temperature (T_g) by 13.48 °C. Still, the temperature corresponding to the maximum rate of weight loss (T_max) remained unchanged.

Optimization Design of Surface Wave Electromagnetic Acoustic Transducers Based on Simulation Analysis and Orthogonal Test Method

The energy conversion of electromagnetic acoustic transducers (EMATs) is typically lower, which seriously restricts the application of EMATs in the field of non-destructive testing and evaluation. In this work, parameters of surface wave EMATs, including structural parameters and electrical parameters, are investigated using the orthogonal test method to improve the transducer’s energy conversion efficiency. Based on the established finite element 2-D model of EMATs, the amplitude of the displacement components at the observation point of a plate is the optimization objective to be maximized with five parameters pertaining to the magnets, meander-line coils, and excitation signal as design variables. Results show that the signal amplitude of EMATs is 3.48 times on in-plane and 3.49 times on out-of-plane, respectively, compared with the original model. Furthermore, a new material (amorphous nanocrystalline material of type 1K107) is applied to optimize the magnetic circuit of EMATs and enhance the eddy current in an aluminum plate to increase the signal amplitude. Finally, the signal amplitudes obtained from the three types of models, that is, the original one, the optimization one after an orthogonal test, and the optimization one with the addition of magnetic concentrators, are analyzed and compared, indicating that the signal amplitude, compared with the original one, is 6.02 times on in-plane and 6.20 times on out-of-plane, respectively.

Investigation of the Effect of Process Parameters on Bone Grinding Performance Based on On-Line Measurement of Temperature and Force Sensors

This study investigates the effect of process parameters on neurosurgical bone grinding performance using a miniature surgical diamond wheel. Bone grinding is an important procedure in the expanded endonasal approach for removing the cranial bone and access to the skull base tumor via nasal corridor. Heat and force are generated during the grinding process, which may cause thermal and mechanical damage to the adjacent tissues. This study investigates the effect of grinding process parameters (including the depth of cut, feed rate, and spindle speed) on the bone grinding performance using temperature and force measurement sensors in order to optimize the grinding process. An orthogonal experimental design with a standard orthogonal array, L₉ (3³), is selected with each parameter in three levels. The experimental results have been statistically analyzed using the range and variance analysis methods in order to determine the importance order of the process parameters. The results indicate that the effect of the cutting depth on the grinding temperature and normal force is the largest, while the effect of the spindle speed on the tangential force is the largest. A high spindle speed would make the temperature rise to a certain extent; however, it significantly reduces the grinding force. At a certain spindle speed, a lower depth of cut and feed rate help to reduce the grinding temperature and force.