ing from temperature gradients in a cylinder were derived by Duhamel (1838).‘ Since that time, about thirty papers have appeared which mainly consider the calculation of thermal stresses in an infinite cylinder subjected to temperature gradients. It is apparent that thermal stresses are not a new or uninvestigated phenomenon. The first quantitative treatment of thermal stress fracture in cerami...

offshore pipelines used for oil and gas transportation are often buried to avoid damage from fishing activities and to provide thermal insulation. thermal expansion and contraction of the pipeline during operation can lead to lateral or upheaval buckling. a safe buried pipeline design must take into account a reliable evaluation of soil uplift resistance and pipe embedment depth. while the cost...

background: the purpose of this study was to investigate the enhanced thermal resistance mechanism of the du145 tumor spheroid cultures as compared to the prostate carcinoma cell line's monolayer cultures. materials and methods: du145 cells were cultured either as spheroids or monolayers. cultures were treated with hyperthermia in a precision water bath (at 43°c for 60 minutes) and/or quercetin...

Poor thermal shock and resistance to crack propagation have had a negative influence on the acceptance of ceramics for components in air breathing engine applications. In comparison with their metallic counterparts, they are less predictable and there is limited historical in-use data available. They have therefore been considered primarily for non-load bearing applications such as flaps and se...

This paper proposed a half-experimental model to reconstruct the die-bonding thermal path of highpower light-emitting diodes (HP-LEDs). In this model, the partially insufficient filling of bonding materials and their directional/random distributions (“filling state” for short) have been taken into consideration. Both the silver-paste structure and the Au/Sn-eutectic structure were analyzed and ...

The thermal-stress resistance and fracture strength behaviour of two oxide ceramics (a hot-pressed pure AI203 and a composite ceramic NTK-HC2) subjected to severe thermal shocks have been investigated. The damage resistance parameter (Kic/of)2 for both ceramics is also determined for a wide range of temperatures (25 ~ to 800 ~ C) and cross-head rates (10 -2 cm min -1 ~ 2.5 m sec -1 ). Fracture ...

Clothing is often made of materials that impede the flow of heat and moisture from the skin to the environment. Consequently, people may suffer from heat stress or cold stress when wearing clothing in different environmental conditions. Therefore it is important to quantify the thermal resistance and evaporative resistance of clothing materials and to consider these properties when selecting ma...

A novel system is developed for measuring the thermal resistance across thin layers of sintered copper wicks of varying porosity. Wicks to be tested are integrated into a passive vertical thermosyphon system and the resistance is measured for a series of input power levels. The wicks are sintered to a thermally conducting pedestal above a pool of de-ionized water and heated from below. The appa...

Model Timo Veijola, Mikael Andersson*, and Antti Kallio Helsinki University of Technology, Faculty of Electrical Engineering, Circuit Theory Laboratory, Otakaari 5A, FIN-02150 Espoo, Finland. phone:+358-0-4512293, fax:+358-0-460224, e-mail:[email protected] *Nokia Research Center. P.O. Box 45, FIN-00211 Helsinki, Finland. Abstract| A simple method for transistor DC parameter extraction is prese...

Deeply understanding HBT thermal characteristics and safe operating area (SOA) is critical to the improvement of the ruggedness and reliability of power amplifiers. In this work, we investigate the device size effect of SOA and thermal resistance by means of experimental measurement, analytical modeling and 3dimensional simulation. For HBTs with a factor of ten variations in emitter area, the S...