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posted by janrinok on Monday March 03 2014, @03:00AM   Printer-friendly
from the if-you-could-see-me-now dept.

hankwang writes:

"For the past couple of days, China's capital has been suffering under severe smog, leaving the sun and skyscrapers barely visible. The highest concentration of small airborne particles (PM2.5) was 0.50 mg per cubic meter, a factor 20 above the Word Health Organization's safe limit. Scientists went as far as comparing this to a nuclear winter. The worst seems to be over for now: today, the monitors are reading 0.180 mg/m3, only a factor 7 above the WHO limit.

The Chinese smog seems to behave differently from the smog in Europe and the US. Existing scientific models developed in the West do not work well. To improve the models and understanding, plans are underway to build a 600 cubic-meter (that's 21,000 cubic ft or 160,000 US gallon) transparent dome as a smog chamber."

[NOTE TO EDITOR: I can't get slashcode to display the mu symbol, so I converted to milligrams] [Ed's Note: Thankyou - but what is it in firkins?]

 
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  • (Score: 0) by Anonymous Coward on Tuesday March 04 2014, @03:12AM

    by Anonymous Coward on Tuesday March 04 2014, @03:12AM (#10419)

    It's a matter of doing things in order. What I suggested you to look at comes before any prototyping or any physical implementation thus, technical details about said implementation.

    What I suggested you to look at could be fairly simulated with software. IMHO, this is where you should start.

    Intuitively, if this is ever going to work, I feel like the positively charged ones would make it much easier to pick up and control the mess but that's just intuition.

    Peace.

  • (Score: 1) by anubi on Tuesday March 04 2014, @06:11AM

    by anubi (2828) on Tuesday March 04 2014, @06:11AM (#10470) Journal

    Often intuition and past experience is most of what I have to go on.

    I love to simulate, but all too often my models, hence anything I get from simulation, is not up to snuff.
     
    God knows how many Spice simulations of mine have given me misleading results due to bad models.

    So I often try empirical approaches to see how well reality matches my models.

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
  • (Score: 2) by hankwang on Tuesday March 04 2014, @09:38AM

    by hankwang (100) on Tuesday March 04 2014, @09:38AM (#10532) Homepage

    What I suggested you to look at could be fairly simulated with software. IMHO, this is where you should start.

    The question is: which software? And then: which settings? Typically, computational fluid dynamics software has many model parameters that need to be set in order to capture the relevant physical effects for the problem at hand, without wasting processing time on effects that do not make a difference. Doing so correctly requires that you have a good grasp of the underlying physics, otherwise it will be garbage in, garbage out. Moreover, once you have this good grasp, it is likely that you can do back-of-the-envelope estimates to see whether what you want to achieve is at all plausible, or likely to be orders of magnitude off.

    Part of my job is doing, outsourcing, and reviewing simulations (gas flow, diffusion, thermal, deformation, particle-gas transport, and others) for engineering purposes (not electrostatic gas filtering, though), and have seen many times that simulations produced nonsense results because the elephant in the room was missed, i.e., some dominant physical effect that was not accounted for.