The NIST ytterbium-doped fiber laser used can provide up to 530 watts of laser output at a wavelength of 1.07 microns. At full power, they were able to deliver as much as 3.5 uN (0.35 mg) of force to the mirror. The experiments showed the expected linear relation between measured force and laser output.
It's just the way coffee is. Coffee is acidic. That's what probably upsets your stomach, especially if you're not eating or drinking other fluids throughout the day. People say that using coffee grounds are excellent for growing plants. BUT, they are only good for growing plants that are acidic soil loving plants.
Roughly two-thirds of Americans drink coffee daily, according to a July 2015 Gallup poll. Coffee can stimulate the movement of stool through the intestines by promoting muscular contractions of the bowels. This short-term stimulation is not significant enough to cause diarrhea in most people.