Please create an account to participate in the Slashdot moderation system


Forgot your password?

Comment: Re:wow, that makes me feel good (Score 1) 359

by jbengt (#49737957) Attached to: Ask Slashdot: Best Way To Solve a Unique Networking Issue?

A station has only one pump per grade of fuel (although in some rare cases of multiple tanks even when they are connected together they may have 2 pumps per grade of fuel).

Actually, it can go either way. You can buy dispensers with built-in pumps - one pump per dispenser per fuel type, with suction piped to the tanks, or you can drop a pump into each fuel tank, with discharge piped to the dispensers. You do have to be careful about minimum positive suction head if you go with a dispenser-mounted lifting gasoline from an underground tank. Cost and complexity can make the fewer tank-mounted pumps a better solution for large installations with a lot of dispensers, anyway, but it is not unheard of to have pumps installed within the dispensers for small installations.

Comment: Re:In other news... (Score 1) 250

by jbengt (#49735147) Attached to: Energy Dept. Wants Big Wind Energy Technology In All 50 US States
On the commercial/industrial side, it is quite common to use demand-limiting software to help reduce energy costs taking into account time-of-day and demand charges. Sometimes energy storage is used for those purposes, also, though that requires a bit more thinking ahead and may be more difficult as a retrofit.

Comment: Re:In other news... (Score 1) 250

by jbengt (#49735117) Attached to: Energy Dept. Wants Big Wind Energy Technology In All 50 US States
You're right when you say that the idea of pre-heating a clothes dryer is stupid. But I have to make a correction on the refrigerator: Most of the "cold" of a refrigerator is not lost when the doors are open (unless left open forever), even if you exchange 100% of the cold air in the refrigerator with room temperature air. Most of the "cold" is held by the mass of the food and other things inside the refrigerator.
That said, you can't really pre-chill an off-the-shelf refrigerator without having a lot of issues with frost and freezing. And the main energy consumption of an efficient, well insulated refrigerator is the work done when you put warm things inside to it cool them down.

Comment: Re:Bridges Are Not Static Structures! (Score 1) 36

by jbengt (#49725545) Attached to: Using Satellites To Monitor Bridge Safety

The author of TFA doesn't have a clue. This idea is useless as bridges, particularly suspension bridges, deflect by much more than 1 cm under traffic and wind loads.

I think the aouthor of TFA knows that:

Bridgemaster Barry Colford observed: “This information is extremely useful for understanding how much the bridge can move under extreme weather conditions. This allows us to decide to close the bridge based on precise deformation information.
"For example, I knew that the bridge can move significantly under high winds but for the first time I know that bridge moved 3.5 m laterally and 1.83 m vertically under a wind speed of 41 m/s."

Comment: Re:Salespeople making salespitch (Score 1) 384

by jbengt (#49725189) Attached to: Microsoft To Teachers: Using Pens and Paper Not Fair To Students
When I did some work for a financial company, the head of operations told me that the department handling collections of bad debt was the most profitable - because by the time the account got to them, the money was already written off and anything they collected counted as pure profit.

Comment: Re:Autopilot? (Score 1) 390

by jbengt (#49720087) Attached to: Feds Order Amtrak To Turn On System That Would've Prevented Crash

I must be missing something.

Aircraft operate in 3 dimensions, trains operate for the most part in one - which implies that there is much less of a chance of 2 planes being at the same place at the same time than 2 trains being at the same place a t the same time. The airplane autopilot flies at certain altitudes depending on the path, and if the plane stays at the assigned altitude, there is almost no chance for crossing paths. Trains going in different directions share tracks in a lot of places, and they can't move out of the way of each other - timing is everything in train safety (hence we have a few time zones rather than hundreds of local times)

Comment: Re:What I don't understand (Score 1) 390

by jbengt (#49719899) Attached to: Feds Order Amtrak To Turn On System That Would've Prevented Crash

Well, if you couple the gps to the odometer, that should work most of the time, even with brief gps outages.

Most of the time isn't considered good enough for train safety. Unlike the interstate, there aren't dedicated lanes going each way - there are a lot of single tracks sharing traffic going in both directions.

fortune: cannot execute. Out of cookies.