15,449 reputation
12148
bio website
location Vancouver, Canada
age 44
visits member for 3 years, 4 months
seen 13 hours ago

Mostly C++ programmer in Vancouver.
Specialising in image processing, 3d modeling, Lidar - I'm really a physicist


Aug
13
comment Dangers of using liquid nitrogen
You can also get nasty cold burns by touching metal pipes that have had LN2 in them.
Aug
13
comment Is anything actually 1 meter long (or 1kg of weight)?
@The Chaz, The meter is now defined in terms of the distance light goes in a certain fraction of a second. As measurements of the speed of light improve we change the definition of the metre since it is much more convenient to have a fixed second and a fixed speed of light. So the metre isn't really fixed anymore
Aug
12
answered Waveguide and ethernet
Aug
11
revised What invisible flicker do different types of light bulbs have?
added 219 characters in body
Aug
11
answered How accurate is the time on a digital clock versus the time on internet clocks?
Aug
11
answered What invisible flicker do different types of light bulbs have?
Aug
10
comment If you focus in on one image, is combining two telescopes really equivalent to a larger mirror?
@strmqm - the interferometer gives you a fourier transform of the image. But not the entire UV plane, just a few lines, points and curves in it (depending on how many baselines you have). You try to recreate an image that matches this transform. The main algorithms are called "memsys" and "clean"
Aug
10
answered If you focus in on one image, is combining two telescopes really equivalent to a larger mirror?
Aug
7
revised How much solar energy hits a rooftop in Israel?
added 5 characters in body
Aug
7
comment How much solar energy hits a rooftop in Israel?
@Yotam - 15% is a reasonable efficency for a commercial panel
Aug
7
comment How much solar energy hits a rooftop in Israel?
It's average incoming sunlight (/m^2 sorry missed that) over a year. It's from the africa map on the wiki page - there is a link to the original source
Aug
7
answered How much solar energy hits a rooftop in Israel?
Aug
6
comment Good books on elasticity
Sports illustrated "swimsuit edition" ?
Aug
3
comment Will an air-filled tire normally gravitate toward being nitrogen-filled just by refilling with air?
The N2 fill is originally an aircraft requirement, and was mainly to remove water which would build up in the tire and freeze at high altitudes. Since you were carrying a pressurised N2 cylinder out to the plane anyway to fill various pneumatics it made sense to use the same for the tires rather than having a separate dry-air cylinder.
Aug
3
comment Charging 12V 150Ah battery
I think it's the combination of biggest standard pickup/SUV battery and largest (cheap) battery top-up solar panel
Aug
3
comment Why are lasers inefficient?
@Steve B - wallplug efficiency? Probably none, certainly not frequency doubled YAG / diode! The way a lumen is defined a green light gives you a lot of lumens/watt, which is a bit of marketing spin for green laser pointers
Aug
3
comment Flood prediction data and code
@whoplisp, local gravity level varies from astronomical level by about 1arc-sec (1/3600 of a degree) and it wouldn't matter anyway because roads and buildings are built to local 'gravity' level
Aug
3
comment Could the cosmic microwave background radiation (CMBR) map be used as a backup for GPS navigation?
Quasars are used to set the reference that GPS is calibrated to iers.org
Aug
3
comment how can you keep a gyroscope turning?
@Georg - commutators was a bit over specific - slip rings would be a better term.
Aug
2
comment Flood prediction data and code
@Georg - it is a big market for cities, especially ones on rivers! IF you have accurate ground based LIDAR (few cm accuracy) then tools like ArcGIS etc will map not only where the water will rise to but there are tools that map flow rates and total volume.