NETZSCH to Supply SpaceX’s Thermal Analysis Laboratory
Netzsch Instruments North America, LLC (Netzsch) is currently the sole supplier to Space Exploration Technologies Corp. (SpaceX) of high temperature thermal analysis instruments used to characterize material properties for space applications. The instruments will be used to fine tune properties of existing materials and to develop materials for use in the demanding environments of space.
SpaceX is transforming the way rockets and spacecraft are made. It is the only private company ever to return a spacecraft from low-Earth orbit, and the first to send a spacecraft to the International Space Station. In October 2012. SpaceX’s Dragon spacecraft again successfully delivered cargo to and from the space station, in its first official cargo resupply mission for NASA.
Netzsch instruments will be used to measure basic material properties along with other thermophysical properties. Some of these properties will include 1st, 2nd and 3rd order transitions, coefficient of thermal expansion and contraction, modulus, energy adsorption dampening, heat capacity, thermal diffusivity, thermal conductivity along with software and heat transfer data to model and build heat management systems.
Experiments Bolster Theory of How Electrons Cool in Graphene
It's a basic tenet of physics that scientists are trying to explain in graphene, single-atom thick sheets of carbon: When electrons are excited, or heated, how quickly do they relax, or cool? A research team supported by the Kavli Institute at Cornell for Nanoscale Science has shed some light on the topic through the first known direct measurements of hot electrons cooling down in graphene.
When electrons travel through graphene, they create a quantum lattice vibration, called a phonon. In doing so, the difference in energy the electron emits must equal the amount gained by the phonon; this is the "cooling" that happens as the system is returning to its equilibrium state, and this movement of electrons is at the heart of understanding how electronic devices work.
The Cornell experiment supports a previous theory that electrons in graphene experience super collisions as they cool. They bump into defects in the crystal lattice, imparting their momentum to the defects, thereby making the cooling process much faster than if the graphene were a perfectly repeating crystal.
Watching electrons move through graphene took some novel experimental legwork. Researchers conceived a setup in which they shot very short laser pulses, about 100 femtoseconds apart, at a piece of conventionally grown graphene. They observed the temperature of the graphene as it heated and cooled at a p-n junction, which is the interface at which electrons travel between two semiconductors. By tracking the magnitude of the current passing through the junction, they essentially used the junction as a tiny thermometer.
Heating the junction with an initial laser pulse, they hit it with a second pulse at specific time delays, comparing the crossover of temperatures. This technique allowed the team to measure the temperature of the system with sub-picosecond time resolution and within a few kelvins of accuracy. Their results agreed very well with the supercollision theory of the rate at which electrons cool in graphene.
The results provide further insights into the fundamental nature of graphene so it can one day be used in anything from photodetectors to non-silicon transistors. It is already well known that graphene shows promise for next-generation electronics because of its near-perfect conductivity, transparency and tensile strength.
Boosting Heat Transfer with Nanoglue
A team of interdisciplinary researchers at Rensselaer Polytechnic Institute has developed a method for increasing the heat transfer rate across two different materials. Results of the team’s study could enable new advances in cooling computer chips and lighting-emitting diode (LED) devices, collecting solar power, harvesting waste heat and other applications.
By sandwiching a layer of ultrathin “nanoglue” between copper and silica, the research team demonstrated a four-fold increase in thermal conductance at the interface between the two materials. Less than a nanometer thick, the nanoglue is a layer of molecules that form strong links with the copper (a metal) and the silica (a ceramic), which otherwise would not stick together well. This kind of nanomolecular locking improves adhesion, and also helps to sync up the vibrations of atoms that make up the two materials which, in turn, facilitates more efficient transport of heat particles called phonons. Beyond copper and silica, the research team has demonstrated their approach works with other metal-ceramic interfaces.
Heat transfer is a critical aspect of many different technologies. As computer chips grow smaller and more complex, manufacturers are constantly in search of new and better means for removing excess heat from semiconductor devices to boost reliability and performance. With photovoltaic devices, for example, better heat transfer leads to more efficient conversion of sunlight to electrical power. LED makers are also looking for ways to increase efficiency by reducing the percentage of input power lost as heat.
Asetek, Inc. Selected To Retrofit Major DoD Data Center with RackCDU Liquid Cooling
Asetek, Inc. has been selected to perform a $2 million project to retrofit of a major Department of Defense (DoD) data center with its direct-to-chip liquid-cooling technology. The product, called RackCDU (short for Rack Coolant Distribution Unit), brings high-performance liquid-cooling directly to the hottest elements inside every server in a data center. The net result is more than 50 percent cooling cost savings, oftentimes having an immediate payback.
This project, which will be managed through DoD’s Environmental Security Technology Certification Program (ESTCP), will leverage Asetek’s technology to convert an existing air-cooled enterprise data center into a high-performance liquid-cooled enterprise data center, without disrupting operations during the transition and with improvements in energy consumption, density (enabling consolidation within existing facilities) and creating opportunities to reuse energy, a form of renewable energy under the Federal mandates.
“The Department of Defense has become very serious about improving data center efficiency, and they are seeking new approaches to address this mission-critical problem,” said Andre Eriksen, Asetek’s CEO and founder. “Hot water direct-to-chip liquid-cooling is a powerful approach that can capture more than 80 percent of the heat generated by a data center and remove it from the building, where it can be cooled for free by ambient air or even reused for building heating and hot water. No power what so ever goes in to actively chilling the water.”