This column deals with the thermal conductivity and melting points of liquid metals. Thinking about liquid metals, many people associate them with high temperatures. It is not widely known that some metallic alloys are liquid below 0�C, with the exception of course of mercury which was already known in ancient times. China's first emperor is said to have been buried in rivers … [Read more...]
On The Hate/Love Relationship Between The U.S. And SI
Last year I devoted some words on correligion: the religious belief in the usefulness of correlations to solve real-life problems. I forgot to mention that correlations have one big advantage; they are dimensionless meaning that they are the same for everyone, including people from outside the US. Unfortunately this is not the case for most common units, and the struggle for … [Read more...]
On The Challenges of Thermal Characterization of High-Power, High-Brightness LED Packages
Introduction In recent years, high-power, high-brightness Light Emitting Diodes (LEDs) have penetrated into an ever-increasing number of lighting applications. For such devices, maintaining a low die temperature is becoming a huge challenge because of the escalating power density (e.g., 200-300 W/cm2 for the latest generation). Active cooling solutions are rarely considered as … [Read more...]
Modeling Multiple Heat Source Problems In Electronic Systems
Introduction Readers of ElectronicsCooling know about the rapid pace of technological developments towards an increasingly higher level of miniaturization and, hence, an incredible increase of dissipation power densities. Thus, restating some very well known facts (such as, we have already attained a level of power density that is comparable to nuclear power stations) would not … [Read more...]
Heat Spreading: Not a Trivial Problem
Introduction Heat spreading is essentially area enlarging: the larger the area, the more heat can be removed at the same temperature difference (subject to certain limits). Unfortunately, except for the simplest of cases, the equations describing heat spreading physics do not have an explicit mathematical solution. Hence, we have to rely on clever approximations or suitable … [Read more...]
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