jubjubbird
Joined 11 years ago
Karma
192
Submissions
31
Member since
Jul 26
Recent submissions
Comment · 10 months ago
Comment · 1 year ago
Here's a cool demo I saw recently that allows a cyclist to specify risk tolerance for busy roads, based on traffic data. Take the direct, busy route, or the roundabout way, using bike paths where available.
Comment · 2 years ago
I'm looking at a legal agreement on my desk to lease 120 acres of productive eastern Nebraska farmland to build a commercial scale solar project. The land would be taken out of production ("sacrificed") for the 50 year lease, with payments about twice what the land leases for for agriculture (soybeans).
Comment · 3 years ago
Here's the LK-99 tie in: the most precise gravity meters in the world are superconducting meters, which require a lot of power (2 kW contonuous) to maintain a helium dewar at 4K. It's tough to make that a field instrument. A compact, stable, room temperature gravity sensor would be a huge advance for hydrogeophysics.
Comment · 3 years ago
The MEMS accelerometers in our phones are in theory sensitive to gravity changes, but they're not nearly sensitive enough. This group is trying to improve the MEMS sensing technology, but it's doubtful it will be as good as classical gravity meters (falling mass, or spring) or quantum (BEC) ones:
https://www.gla.ac.uk/research/beacons/nanoquantum/wee-gglas...
One important distinction is between measuring gravity (generally, acceleration in the vertical direction) and the gravity gradient. The latter is generally easier and more useful for navigation.
Comment · 3 years ago
Navajo Generating Station, which was the largest coal-fired ppwer plant in the western U.S. and powered CAP pumping stations, closed in 2019 along with the accompanying coal mine.
Comment · 3 years ago
Speaking of Albuquerque, this just-published paper shows how measuring the change in acceleration due to gravity can be used to map aquifer storage change. Importation of San Juan River water has made a big difference.
Comment · 4 years ago
Too bad Google gets the credit for the amazing https://www.shakealert.org system developed by the USGS and other public entities. Altering the user is the easy part, detecting the earthquake is the hard part.
Comment · 4 years ago
Seems like more often than not I see them folded up, not in use. Even with the price of diesel. I wonder how much they save?
Comment · 4 years ago
Apologies for the paywall, but this paper describes imaging cargo containers with gravity gradient sensors (to look for, e.g., plutonium):
https://ieeexplore.ieee.org/document/4215058
Basically you can image anything if there is a density contrast, it's "just" a matter of how good your sensor and inversion algorithm is.
I spend my day-to-day working on measuring gravitational changes to determine groundwater storage change. There's a huge difference between demonstrating something in the lab vs. building an actual field instrument you can use in the real world.
Comment · 5 years ago
If you just want some nice (public domain) art to hang on your wall:
https://www.gao.gov/products/gao-24-106924