Recent content by christopher.s

  1. C

    A Difference between an optical and an acoustic phonon

    Fill a glass with water and sand. Rotate the glass about it's axis in a sinusoidal fashion. If you rotate slowly enough, the particles will move roughly in phase with the glass. If you rotate fast enough, the particles will begin to move out of phase with the glass. This is analogous to acoustic...
  2. C

    What is the root cause of cancer

    I would say that the "root" cause of cancer is metabolic dysfunction. I think focusing on the genes can cause one to lose sight of what actually constitutes a "healthy" cell vs. one that is damaged. For instance, if you look at levels of LDH (lactate dehydrogenase, which is an enzyme that...
  3. C

    I saw something unexplainable while soldering

    There is most likely a flux core in your solder. Flux helps the solder to flow on the parts being soldered. When it is heated, it vaporizes. Some of the flux condenses on the cooler solder pad.
  4. C

    Absorption and emission of light

    I guess the simple answer is that yes, usually light that is absorbed is turned into heat. It is not as simple to say that an electron moving from a ground state to an excited state gets "hotter," though. The kinetic theory of temperature can be used to explain what is happening to objects as...
  5. C

    Strong, Low Friction material better than teflon?

    Look at Rulon, several different flavors.
  6. C

    Have you had experience with hydrofluoric acid in a cleanroom setting?

    We routinely use HF acid to etch aluminum, it is referred to as a "bright dip" and is usually concentrated at 5%. I'll admit when I first started working with it, I was very leery. It didn't help that people here didn't understand some basic safety concerns with it and were storing used dip in...
  7. C

    Working in a lab with magnetic fields: Bio-hazardous?

    The noise would probably lead to more immediate physical stress than the static magnetic field. Have you done any searching? A simple google search for static magnetic fields bio hazard returned a few good pieces. Bottom line; the magnetic field definitely will have some biological effects, but...
  8. C

    Does reflection change the frequency of light?

    So what you are asking is if a beam of light (monochromatic) is incident on a surface that is not perfectly reflecting (i.e. some absorption, or transmission,) and loses some energy, does the corresponding wavelength of light change? I think the answer is in most cases is no, as Soren said it is...
  9. C

    Is there a see-through material with low outgassing rate?

    Borosilicate or aluminosilicate glass could work, but would require the use of a getter or pump to maintain that kind of pressure. There is also the risk of implosion, and it would probably be difficult to find someone to build a chamber that large. W.r.t. constructing the chamber sliced down...
  10. C

    What is the role of silicon oxide in graphene visibility experiments?

    Please see this reference http://www.condmat.physics.manchester.ac.uk/fullpub/29%20Appl%20Phys%20Lett%2091%20063124%202007.pdf
  11. C

    Understanding Premature Graying in Men: Causes, Treatment, and Normalcy

    Check out these references; http://www.pccarx.com/what-is-compounding/compounding-articles/item/223-pseudocatalase-oxidative-stress-cure-for-gray-hair http://www.fasebj.org/content/23/7/2065.long
  12. C

    Does the Ionizing Himalayan Salt Lamp work?

    Not saying that any of the purported health claims are legitimate, but; Can we qualitatively measure the charge of the air around us, say in a room? For instance, we have a clean room at work that uses an ionizing blower to hopefully mitigate dust. I can tell you that there is a definite...
  13. C

    Mysterious boiling phenomenon during experiment

    The leidenfrost effect is the correct explanation. The way I've had it explained to me is that as the metal cools to a point where the temperature difference does not create as effective of a vapor shield, the heat transfer from the metal to the LN2 drastically increases for a moment. Basically...
  14. C

    Benefits of Nitrogen in Venting UHV Systems?

    My understanding is that during the pumping of a stainless UHV vessel, you will initially desorb more volatile compounds like water vapor, etc. Once these compounds have been desorbed from the surface, the process moves from strictly desorption to a diffusion/desorption scheme. Once you expose...
  15. C

    Deposit Indium Film on Metal Bar - Cheap Prototyping Method

    It might be easier to obtain bulk indium and melt it on to your connector using an indium flux. We do this occasionally as a thermal interface between assemblies. It might be more difficult to get a very precise or consistent thickness, but the same is true for electroplating. I have never...
Back
Top