The applet calculates mass flow rates through pipes and orifices over the whole range of the gas rarefaction. Gas rarefaction and viscosity can be calculated also by Gas Dynamics Toolbox. If you notice problems with calculations, please, let me know.
Key words: Rarefied gas, Knudsen number, gas rarefaction, flow rate, throughput, pipe, tube, channel, orifice, Poiseuille flow, thermal creep, thermolecular pressure difference, vacuum, microfluidics

• Rarefied gas flow through a long tube at any pressure ratio.
  Paper.
• Free molecular flow through a tube of arbitrary length
  Paper.
• Rarefied gas flow through a short tube into vacuum
  Paper.
• Rarefied gas flow through a long conic tube
  Paper.
• Thermomolecular pressure difference for a long tube at any temperature ratio.
  Paper
• Rarefied gas flow through a thin orifice
  Paper.
• Rarefied gas flow through a long rectangular channel
  Paper
• Rarefied gas flow through a long elliptical tube
  Paper