The manufacturing of novel melamine-formaldehyde rigid foam material, by blowing the (MF) resin emulsion with pentane and further catalytic thermal curing, is presented in this work. process foaming described terms particular parameters, which are; proportions blowing, emulsifying agents. examination foam, SEM images, shows that pore sizes are range from 150 to 250 µm. characterization obtained...

The development of the transformer insulation failure undergoes three stages: insulation aging, incipient faults and a short circuit. This paper presents a complete scheme to simulate single-phase transformers with insulation deterioration and arcing phenomena i.e. in the first two stages. The approach incorporates Transmission Line Methods (TLM), Jiles-Atherton Hysteretic Model, Composite Cass...

The development of the transformer insulation failure undergoes three stages: insulation aging, incipient faults and a short circuit. This paper presents a complete scheme to simulate single-phase transformers with insulation deterioration and arcing phenomena i.e. in the first two stages. The approach incorporates Transmission Line Methods (TLM), Jiles-Atherton Hysteretic Model, Composite Cass...

a unique high frequency transient overvoltage surge suppressor for the protection of motors and transformers from steep wave-front, short rise-time, high magnitude, spikes, surges and other transient voltages, generated by switching, lightning and other sources. The protective characteristics of ZORC: Eliminates inter-turn insulation failures Extends the life of machine insulation Eliminates mu...

Epoxy composites are broadly used as an electrical insulation for the high voltage applications since only such materials can fulfill particular mechanical, thermal, and dielectric requirements. However, properties of the final product are strongly dependent on proper manufacturing process with minimized material failures, as too large shrinkage, voids and cracks. Therefore, application of prop...

1. Abstract Topology optimization is employed to define the geometry of the cross-section of any masonry block that minimizes its thermal transmittance, with the aim of maximizing the thermal insulation of masonry buildings. Constraints on the mechanical properties of the block are also prescribed. The effect of the design constraints on the optimal layout of the blocks is investigated. The the...