Applications of new technology in power substations
The authors describe the applications of some of the more modern technologies to instrument designed specifically to operate in utility substation environments. Particular emphasis is placed on the use of CMOS logic, processor, and memory circuits, high-density flexible magnetic disk media, and high-capacity Winchester technology storage devices. The operating history of a number of units over a five-year period is reported, as well as the steps taken to protect these devices in a hostile environment. In addition, areas requiring specific improvement and adaptation are noted.<<ETX>>
Measurement of switching transients in 115 kV substation
Bus current transients, electric and magnetic field transients, and current transients coupled onto control and CT cables produced by switching operations in a 115 kV ring bus have been measured and characterized. The similarities and differences among transients observed when energizing and deenergizing relatively short sections of bus during disconnect switch and circuit breaker opening and closing operations are summarized and discussed. The results are used to further the understanding of switching transient characteristics and to validate a model that predicts the detailed nature of the transients reported, for use in ongoing investigations to assure continued satisfactory performance in substation protection equipment. >
Engineering bio-inks for 3D bioprinting cell mechanical microenvironment
Three-dimensional (3D) bioprinting has become a promising approach to construct­ing functional biomimetic tissues for tissue engineering and regenerative medicine. In 3D bioprinting, bio-inks are essential for the construction of cell microenviron­ment, thus affecting the biomimetic design and regenerative efficiency. Mechanical properties are one of the essential aspects of microenvironment, which can be char­acterized by matrix stiffness, viscoelasticity, topography, and dynamic mechanical stimulation. With the recent advances in functional biomaterials, various engineered bio-inks have realized the possibility of engineering cell mechanical microenviron­ment in vivo. In this review, we summarize the critical mechanical cues of cell micro­environments, review the engineered bio-inks while focusing on the selection princi­ples for constructing cell mechanical microenvironments, and discuss the challenges facing this field and the possible solutions for them.