Although metal technology has advanced a long way over the years, it still has its limits. Consider that conventional pushrods already have a fair bit of beef to them and consider that it does not take much to make them fail. Also consider that their primary load is under compression (They have the suck stroke which is tension, but not exactly a high-load stroke compared to bang:) ).
Now the 'pushrod' being discussed here is in fact a 'pull'rod. i.e, it's primary load is under *tension* not compression. (likewise, it will have a light-duty suck stroke which will compress the rod). Also consider that this rod will have to be very long. If we had failing push-rods, you can bet this thing is going to have to be *very* strong to not snap under extreme tension.
As a disclaimer, I am not familiar with relative compressive & tensile strengths of high-tech alloys. I am assuming that they are, in general, far more durable under compression than tension, right? If not, then I retract this whole thing:)
Yeah I get that about piston momentum, the thing I don't get is how the piston speed is lower on one of these.
Let's say it's a 2l displacement engine with 4 pistons with a square bore*stroke of 8.6cm*8.6cm, running at 1200rpm.
For an Otto-cycle:
Crankshaft is rotating 20 times/sec
Piston goes from BDC to TDC 20 times/sec and takes 1/40th/sec to do it
Piston travels 8.6cm in 0.025s.
I don't know the math to calculate max speed, but avg piston speed going from BDC to TDC is 3.44m/s
Now with the opoc engine, you still get 4 pistons, the displacement is still 2l. Given the same bore, each piston still has to travel the same distance as its Otto counterpart, if the engine is rotating at the same speed.
How is it that it is going any slower in the opoc, for the same displacement, bore & rpm?
I just realised, all my numbers were redundant as they'd be the same on the opoc.
I know you jest, cos of the flat layout, but i'm curious. How is this opposing piston layout superior to a regular Otto Cycle engine? he talks of reduced piston speed being a big advantage. Sure, the pistons only have to travel half as far as a conventional engine for a given *cylinder* displacement, but for a given *piston* displacement (with the same bore), it would be no different. You'd just be having twice as many cylinders. You'd still have 4 pistons and you wouldn't have to deal with, which looks to me a bit of a weak-spot, that silly looking *pull*rod setup. OK, so the engine can be perfectly balanced, trivially, and it's running 2-stroke rather than 4, so less power waste there, but the piston speed nonsense is rubbish. Or am I missing something here?
The clutch idea though is pretty cool. Disengage & power down part of the engine, what a good way to reduce emissions. This would not work on a regular engine as it would vibrate itself out of the car:)
I wonder if there is a device that would only allow electricity to pass in one direction. If there was, I could envision a small array of these devices set up in a kind of diamond pattern, such that AC going in could end up as DC coming out. Granted, the DC would still have the peaks and troughs of the AC, but maybe that could be 'smoothed' out with some kind of intermediate electricity 'buffer' if there is such a thing.
I imagine you could have large supercapacitor banks at the home charging station to store up the required energy over time, ready for the 6min 900KW burst. That would make this do-able on existing infrastructure.
Now the electricity companies can start making more money when they upgrade home services (on a request basis) to 200A 3-phase [regional high voltage, ~300-500]V 'industrial grade' power. I'm not up on 3-phase, how much power would 200A @ say, 500V give?
Is it as simple as 3*200A*500V=300KW? (I know, still not enough.
Until recently, I thought that they were building from wood in the UK. There were some new houses built opposite my house when I was younger that were framed with wood. However, I recently found out that the insurance companies there won't touch wood houses and that there was a spate of building houses from wood in the 80's. That's about when those ones opposite went up. Maybe the codes were temporarily laxed?
As for the prefab, the type I was referring to was not for 'project' type council houses. This was for individual custom house builds. You wouldn't know it was a prefab build by looking at it. It just happened to be on my bike ride to work near Munich so I was watching with interest. The main structure (ground floor sections, ground floor walls, 1st floor sections, 1st floor walls) went up in, I kid you not, 2 days. I watched my wood-framed house in Canada being built and although I had the same 'fook me that was quick' feeling once the main framing started, it was by no means even comparable to the speed the prefab one in Munich went up.
I think the prefab options I mentioned above would be both. It's quicker/easier to deliver and raise a wall rather than deliver, take 2*4's to the floor, build wall on the floor, raise wall, install insulation/poly when house is framed.
How much cheaper, really? Let's take the example of having modular prefabbed floors & exterior walls that are available in many configurations so you have design freedom to build what you like. These prefabbed sections can be mass produced, cheaply, and the right combination shipped to the location. Once there, you flip it up, use whatever connection method is needed for the walls and lay down the interlocking floor sections. The prefab sections I saw near Munich even had insulation built into them.
With wood, the wood has to be processed, granted at a much lower cost than the concrete section fabbing. Then it has to be shipped just like the prefabbed. But then it changes - The amount of labour that goes in to laying floor joists, laying & fastening floor sheets (which all results in a boing-ey floor anyway), framing wall sections on the floor then raising them, then ultimately installing insulation and poly, is quite a lot more than I imagine an efficient prefab production line would be.
Note that I have no actual idea of the relative costs of anythign above, but i'm genuinely curious as i'm sure that an efficient prefab system could turn out cheaper, or at least on-par. Then you get the benefit of stronger houses. Oh and there's nothing to stop you doing the internal framing with wood/metal studs, so you still get the freedom to change/customise the internal layout.
I do agree, however, that pure brick or poured concrete buildings would be more expensive. I also agree that *right now* it would be more expensive as an efficient prefab infrastucture would need to be built up over time. With the "PROFIT NOW, NOT LATER!!!" mentality of businesses over here, this is not likely to ever happen.
I always wonder this. Even in non-hurricane zones, houses in Europe (England & Germany is all I know about) are made of brick or poured/prefabbed concrete.
Why does it have to be so different over here? It's always boggled my mind with all the wooden houses going up. Even 'brick' houses are just wooden houses with a brick fascia( Yes, I know, some older buildings are proper brick).
It's everywhere. I just tested it on a random newish Ubuntu install (Well, 10.04) and the exploit works. It *does* say in the article that it's set up this way as default.
I'd expect this is a pretty common vulnerability out there.
Actually, it should be OK.
It's what it's made of. Back in the 22nd Century aerospace engineers discovered that after a plane crash, the only thing that always survives intact is a cute little doll, so they made Red Dwarf* out of the same stuff.
*OK OK. I searched the quote and realised it was Starbug, not Red Dwarf, I forgot about that. Still, I wanted the quote anyway. Sue me.
"In a classical interferometer, first developed in the late 1800s, a laser beam in a vacuum hits a mirror called a beamsplitter, which breaks it in two".
And elsewhere:
"In 1917, Albert Einstein established the theoretic foundations for the LASER"
Indeed. My response "Not in itself" was attributed to that fact.
However, if he *thought* he was trying to be ironic rather than just punny, then the situation becomes a little ironic due to the proposed nature of his post.
Not in itself. But if he was seriously trying to be ironic by doing so, then the fact that it was not ironic and in a post requesting correct usage of irony, was itself ironic.
Slashdot Mirror
Although metal technology has advanced a long way over the years, it still has its limits. Consider that conventional pushrods already have a fair bit of beef to them and consider that it does not take much to make them fail. Also consider that their primary load is under compression (They have the suck stroke which is tension, but not exactly a high-load stroke compared to bang :) ).
:)
Now the 'pushrod' being discussed here is in fact a 'pull'rod. i.e, it's primary load is under *tension* not compression. (likewise, it will have a light-duty suck stroke which will compress the rod). Also consider that this rod will have to be very long. If we had failing push-rods, you can bet this thing is going to have to be *very* strong to not snap under extreme tension.
As a disclaimer, I am not familiar with relative compressive & tensile strengths of high-tech alloys. I am assuming that they are, in general, far more durable under compression than tension, right? If not, then I retract this whole thing
Yeah I get that about piston momentum, the thing I don't get is how the piston speed is lower on one of these.
Let's say it's a 2l displacement engine with 4 pistons with a square bore*stroke of 8.6cm*8.6cm, running at 1200rpm.
For an Otto-cycle:
Crankshaft is rotating 20 times/sec
Piston goes from BDC to TDC 20 times/sec and takes 1/40th/sec to do it
Piston travels 8.6cm in 0.025s.
I don't know the math to calculate max speed, but avg piston speed going from BDC to TDC is 3.44m/s
Now with the opoc engine, you still get 4 pistons, the displacement is still 2l. Given the same bore, each piston still has to travel the same distance as its Otto counterpart, if the engine is rotating at the same speed.
How is it that it is going any slower in the opoc, for the same displacement, bore & rpm?
I just realised, all my numbers were redundant as they'd be the same on the opoc.
And yeah, I hate that stonking 'pull'rod.
It's nothing of the sort. Watch the video and see how it works :)
I know you jest, cos of the flat layout, but i'm curious. How is this opposing piston layout superior to a regular Otto Cycle engine? he talks of reduced piston speed being a big advantage. Sure, the pistons only have to travel half as far as a conventional engine for a given *cylinder* displacement, but for a given *piston* displacement (with the same bore), it would be no different. You'd just be having twice as many cylinders. You'd still have 4 pistons and you wouldn't have to deal with, which looks to me a bit of a weak-spot, that silly looking *pull*rod setup. OK, so the engine can be perfectly balanced, trivially, and it's running 2-stroke rather than 4, so less power waste there, but the piston speed nonsense is rubbish. Or am I missing something here?
:)
The clutch idea though is pretty cool. Disengage & power down part of the engine, what a good way to reduce emissions. This would not work on a regular engine as it would vibrate itself out of the car
Grunthos the flatulent? Is that you?
So I suppose you haven't heard about the Golgafrinchans?
RA108
I wonder if there is a device that would only allow electricity to pass in one direction. If there was, I could envision a small array of these devices set up in a kind of diamond pattern, such that AC going in could end up as DC coming out. Granted, the DC would still have the peaks and troughs of the AC, but maybe that could be 'smoothed' out with some kind of intermediate electricity 'buffer' if there is such a thing.
Interesting.
I imagine you could have large supercapacitor banks at the home charging station to store up the required energy over time, ready for the 6min 900KW burst. That would make this do-able on existing infrastructure.
Now the electricity companies can start making more money when they upgrade home services (on a request basis) to 200A 3-phase [regional high voltage, ~300-500]V 'industrial grade' power. I'm not up on 3-phase, how much power would 200A @ say, 500V give?
Is it as simple as 3*200A*500V=300KW? (I know, still not enough.
I didn't know this. The ones I saw were prefab concrete.
:)
I happen to *know* that the prefab concrete parts only come in concrete
Until recently, I thought that they were building from wood in the UK. There were some new houses built opposite my house when I was younger that were framed with wood. However, I recently found out that the insurance companies there won't touch wood houses and that there was a spate of building houses from wood in the 80's. That's about when those ones opposite went up. Maybe the codes were temporarily laxed?
As for the prefab, the type I was referring to was not for 'project' type council houses. This was for individual custom house builds. You wouldn't know it was a prefab build by looking at it. It just happened to be on my bike ride to work near Munich so I was watching with interest. The main structure (ground floor sections, ground floor walls, 1st floor sections, 1st floor walls) went up in, I kid you not, 2 days. I watched my wood-framed house in Canada being built and although I had the same 'fook me that was quick' feeling once the main framing started, it was by no means even comparable to the speed the prefab one in Munich went up.
These are just my observations.
And I forgot to mention another step of the wood-option. Fitting the sheathing to the exterior.
I forgot to address "easier" and "quicker".
I think the prefab options I mentioned above would be both. It's quicker/easier to deliver and raise a wall rather than deliver, take 2*4's to the floor, build wall on the floor, raise wall, install insulation/poly when house is framed.
How much cheaper, really? Let's take the example of having modular prefabbed floors & exterior walls that are available in many configurations so you have design freedom to build what you like. These prefabbed sections can be mass produced, cheaply, and the right combination shipped to the location. Once there, you flip it up, use whatever connection method is needed for the walls and lay down the interlocking floor sections. The prefab sections I saw near Munich even had insulation built into them.
With wood, the wood has to be processed, granted at a much lower cost than the concrete section fabbing. Then it has to be shipped just like the prefabbed. But then it changes - The amount of labour that goes in to laying floor joists, laying & fastening floor sheets (which all results in a boing-ey floor anyway), framing wall sections on the floor then raising them, then ultimately installing insulation and poly, is quite a lot more than I imagine an efficient prefab production line would be.
Note that I have no actual idea of the relative costs of anythign above, but i'm genuinely curious as i'm sure that an efficient prefab system could turn out cheaper, or at least on-par. Then you get the benefit of stronger houses. Oh and there's nothing to stop you doing the internal framing with wood/metal studs, so you still get the freedom to change/customise the internal layout.
I do agree, however, that pure brick or poured concrete buildings would be more expensive. I also agree that *right now* it would be more expensive as an efficient prefab infrastucture would need to be built up over time. With the "PROFIT NOW, NOT LATER!!!" mentality of businesses over here, this is not likely to ever happen.
I always wonder this. Even in non-hurricane zones, houses in Europe (England & Germany is all I know about) are made of brick or poured/prefabbed concrete.
Why does it have to be so different over here? It's always boggled my mind with all the wooden houses going up. Even 'brick' houses are just wooden houses with a brick fascia( Yes, I know, some older buildings are proper brick).
It's enabled by default. I tested it.
It's everywhere. I just tested it on a random newish Ubuntu install (Well, 10.04) and the exploit works. It *does* say in the article that it's set up this way as default.
I'd expect this is a pretty common vulnerability out there.
Actually, it should be OK.
It's what it's made of. Back in the 22nd Century aerospace engineers discovered that after a plane crash, the only thing that always survives intact is a cute little doll, so they made Red Dwarf* out of the same stuff.
*OK OK. I searched the quote and realised it was Starbug, not Red Dwarf, I forgot about that. Still, I wanted the quote anyway. Sue me.
Oh never mind, I get it now. Classical inteferometers developed in the 1800's used light, but newer 'classical' inteferometers use laser.
Still bad wording though.
"In a classical interferometer, first developed in the late 1800s, a laser beam in a vacuum hits a mirror called a beamsplitter, which breaks it in two".
And elsewhere:
"In 1917, Albert Einstein established the theoretic foundations for the LASER"
So what laser did they use in the 1800's?
Pint of the African-American stuff please bartender!
I believe Scunthorpe in the UK had similar problems in the early days too.
Indeed. My response "Not in itself" was attributed to that fact.
However, if he *thought* he was trying to be ironic rather than just punny, then the situation becomes a little ironic due to the proposed nature of his post.
Not in itself. But if he was seriously trying to be ironic by doing so, then the fact that it was not ironic and in a post requesting correct usage of irony, was itself ironic.