In this paper, a Markov maintenance model for predicting the remaining life of transformer insulation has been developed. It incorporates various stages of insulation deterioration and minor maintenance state. Given that a current state of insulation ageing has been reached, from a diagnostic testing and inspection, this model is capable of computing the predicted average time before insulation...

The natural convection flow over a surface embedded in saturated porous media is encountered in many engineering problems such as the design of pebble-bed nuclear reactors, ceramic processing, crude oil drilling, geothermal energy conversion, use of fibrous material in the thermal insulation of buildings, catalytic reactors and compact heat exchangers, heat transfer from storage of agricultural...

The starting material used in this study was a cake generated during thermo-mechanical fractionation of sunflower (Helianthus annuus L.) whole plant in a twin-screw extruder. It was slightly deoiled (16.7% of oil in dry matter). Composed mainly of fibers and proteins, it could be considered as a natural composite and was processed successfully into fiberboards by thermo-pressing. This study aim...

The Mars environment presents a number of challenges to the current extravehicular activity (EVA) architecture. The Martian gravity of 0.38 g is more than twice that of lunar gravity, resulting in more stringent mass requirements for the spacesuit and portable life support system (PLSS). The Martian atmospheric pressure of 7 mmHg (0.933 kPa, 0.135 psi), combined with seasonal temperature swings...

In this paper, a novel algorithm for estimating clothing insulation is proposed to assess thermal comfort, based on the non-contact and real-time measurements of the face and clothing temperatures by an infrared camera. The proposed method can accurately measure the clothing insulation of various garments under different clothing fit and sitting postures. The proposed estimation method is inves...

The operation of Nb–Ti superconducting magnets in He II relies on superfluidity to overcome the severe thermal barrier represented by the cable electrical insulation. In wrapped cable insulations, like those used for the main magnets of the Large Hadron Collider (LHC) particle accelerator, the micro-channels network created by the insulation wrappings allows to efficiently transfer the heat dep...

The objective of the study was to evaluate the detection efficiency of micro-vacuum surface sampling and surface wet wipe sampling in homes that had been identified with vermiculite attic insulation and/or other asbestos containing materials. Surface samples were collected pre and post weatherization activities and analyzed by transmission electron microscopy. Baseline sampling revealed that we...

Aerogels are porous, low density (0.8–0.001 g cm −3 ) solid materials with a high specifi c surface area; they have been recognized as promising materials for a plethora of applications, such as transparent thermal or acoustic insulation, membrane separation, lightweight construction, supported catalysis, superabsorbency, and water purifi cation. [ 1–10 ] Advanced mateAmbient-Dried Cellulose Na...

We describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. The method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, the...

Numerous studies have estimated the optimum thickness of thermal insulation materials used in building walls for different climate conditions. The economic parameters (inflation rate, discount rate, lifetime and energy costs), the heating/cooling loads of the building, the wall structure and the properties of the insulation material all affect the optimum insulation thickness. This study focuse...