it's always a closed circuit. just depends on the timescale.
In thermodynamics a closed-system doesn't have any mass transfer across the system boundary. If the data center is using evaporative cooling which transfers water vapor (mass) out of the data center (system) it is an open system.
Whether the parents specific innovations are of interest to 'you' or not isn't the point. What he is talking about is innovations that would increase the feel of immersion in the game. Obviously, these will differ between people.
Ultimately, Duke3D created an immersive environmental like no other game of the time and most importantly it was fun. I remember putting dozens of pipe-bombs around a laser trip mine just because it was fun. A single trip mine alone would be enough to kill an enemy, but adding some pipe bombs just so Duke says "Let God Sort Em' Out" is classic.
Blowing up an enemy in another room while watching on the security camera or giving money to the strippers when my parents weren't watching, it was great. It was innovative and entertaining.
Jet-packs, subways, earth-quakes, novel weapons, snide comments, and more it really set the bar for all games that would follow. Kicking the final boss' Cyclopes eye through the goal post is just awesome. "Game Over" enough said.
Something that might make it better is to implement a penalty when clicking that "flag as inappropriate" link. It should harm the person's votes, or be somehow detrimental (e.g. could only be done once a day and would also remove all your other votes). People will still self-sacrifice to remove something that's grossly inappropriate such as racial comments.
I was thinking the same thing. If there was a mod system similar to this site's, with a limited number of mod points. The cost modding down a question could be much higher than the cost of modding up a question.
Something like modding up a question costs 1 point, while modding down costs 3 points. If you only are given 5 points for a given duration, then it would become less effective to mod questions down. Also, in this case one would only be able to mod down a single comment, until the next mod cycle started.
I mean, unless the processor *needs* to be at LN2 temperature wouldn't it be more practical just to increase the flow rate of a water cooling system?
The processor is never going to be the same temperature as the liquid nitrogen (or any cooling median). As long as there is thermal resistance and/or heat being dissipated there will be some temperature difference.
You could just increase the flow rate of a water cooling system, but that is not without issues either. For example, pumping power increases exponentially with flow rate and heatsink geometry is typically optimal for a given flow rate.
Using the liquid nitrogen is just an easy way to get a high heat transfer rate by maximizing the temperature difference between the processor and cooling medium.
What I wonder is why people just put the liquid nitrogen is simple hollow copper tube. This isn't any different than a natural convection air heatsink. Why not create fins inside and try to maximize surface area and convection?
But the engine in a truck or bus is not fixed speed. It varies according to driving conditions, and there is a loss in efficiency due to the need to allow for the flexible load. If you use an engine merely for charging the battery then it can be a fixed speed, fixed load engine - I.e. it can run at peak efficiency whenever it is running, and the efficiency can be higher than a more flexible engine.
The point you make is spot on. However, why isn't more effort put into continuously/infinitely variable transmissions. Generally speaking the operating range of the engine is inversely proportional the number of gears in the transmission. The less gears the wider the engine operating range, the more gears the smaller the operating range.
With enough gears one can choose the operating speed independently of the actual road speed. In such a case wouldn't the engine be able to operate at the peak efficiency for any given engine load?
But the engine in a truck or bus is not fixed speed. It varies according to driving conditions, and there is a loss in efficiency due to the need to allow for the flexible load. If you use an engine merely for charging the battery then it can be a fixed speed, fixed load engine - I.e. it can run at peak efficiency whenever it is running, and the efficiency can be higher than a more flexible engine.
The point you make is spot on. However, why isn't more effort put into continuously/infinitely variable transmissions. Generally speaking the operating range of the engine is inversely proportional the number of gears in the transmission. The less gears the wider the engine operating range, the more gears the smaller the operating range.
With enough gears one can choose the operating speed independently of the actual road speed. In such a case wouldn't the engine be able to operate at the peak efficiency for any given engine load?
Err... yikes. If that happens, your vehicle wasn't roadworthy to begin with, or the road conditions were so bad that applying the brakes wouldn't have been that much better.
I agree, and know for fact, engine braking can be done regularly and in a safe manner. But when done incorrectly or excessively it can and will upset the balance of the car. In a front wheel drive vehicle it may cause understeer but in a rear-wheel drive car it will cause oversteer.
I have locked up the rear-wheels in my car several times engine braking into a gear that requires excessive engine speed. Wheel lock can be reduced by rev-matching the engine speed for the lower gear but there is still a risk of sending more braking force to the tires than they can handle.
It has nothing do with the roadworthiness of the vehicle, it is basic vehicle dynamics.
Likewise in a RWD car with a manual transmission, running the engine to near red-line and then abruptly letting off the throttle can severally upset the balance of the car.
If it's being used to cool CPUs, I don't think it needs to be liquid at room temperature, since the area near most modern CPUs is considerably hotter than that! If your CPU is running at room temperature, you probably don't need much cooling (and if you do, you're going to need a much more elaborate system than merely one based on a liquid metal, since a passive heat-sink isn't going to take you anywhere below room temperature).
This may be true when the machine is running, but what about when it is initially started? As the processor begins to warm up the cooling medium will still be solid. Since solids are hard to pump the heat generated by the processor must be transported by conduction only. If the designer goes through the trouble of using a liquid cooler, it is probably safe to say that conduction only heat removal is not sufficient. So this presents some serious transient start-up issues.
Cars, televisions, players, music, computers... are there really any electronics intended to last 30 years any more? Yes there are a lot. High grade electronics for critical applications are expected to last a very long time. It is not uncommon for military and aerospace equipment to have warranties of +15 years. As an electronic packaging engineering in the aerospace field I can tell you that Tin Whisker is taken very seriously.
However, with that said there are a lot design techniques that are applied to aerospace electronics but are not applied to commercial electronics. I am not sure that it really matters, does anyone really want their Dell to last for 15 years?
uhm, if I recall it correctly, the failed design of tacoma bridge didn't had any legal consequences No, if you remembered correctly you would know that the bridge failed because it was vibrating in a manner never before seen. The air moving around the deck was causing an unforeseen mode of vibration, a problem that falls it the classification of Fluid-Structure Interaction (FSI). FSI problems might have been better understood by aerospace engineers but had little relevance to civil engineering, at the time anyway. The civil engineers didn't "forget" anything, they just simply didn't understand the problem.
According to the military this was not about 'showing up' China. Their intent was to test the Ballistic Missile Defense system which they do not consider an anti-satellite system.
"There have been many successful missile defense tests to date, which lead us to believe that the system works, and that we should be building upon it. So we are taking this step, as General Cartwright made abundantly clear last week, not to test our anti-satellite capabilities. We did that in 1985. Been there, done that," a DOD spokesman said.
What happens if they try to shoot it down and miss? Especially after the successful Chinese demonstration. Would that drive other nations to push their military development programs even harder?
as the temp goes up 10 degrees, the life expectancy of the parts goes down 50 percent. Actually there is no technical data that supports this. Long ago (before my time) there was something similar written in a Military Standard, but that section has since been removed. If you are interested in MIL STD number I would have to look around.
a 10 degree Celsius rise from room temperature puts most equipment at its knife edge. a 20 degree rise is going to be statistically quite significant in early failures. Again this not true partly because the 10C rule doesn't apply, and partly because the change in temperature affect on a part will depend on the initial temperature. That is a change from 15C to 25C will be less detrimental than 115C to 125C. Even that is overly simplified and should not be considered absolute.
Our IT department has requested that everyone 'log-out' but leave their machines on so that they can be updated. Seems redundant since they also send out an email when new updates are available, and if the updates are not installed within a few days they eventually force the install. Personally, I just update when I see the email and turn my machine off at night mostly out of fear of a head crash and loss of data while I am away.
IANAP but I think by being a great absorber, it becomes a great emitter too: Black body. So it may not actually get much hotter than something less black. I guess it depends on where the equilibrium point is, and I don't have any intuition about that. Kirchoff's Law (emissivity = absorptivity) doesn't always apply when dealing with solar radiation. The problem is that the majority of solar energy is the visible spectrum. So dark colors will absorb more solar energy than light colors. However, if the surface is near room temperature it will tend to emit the energy at infared wavelengths. If the surface emssivity/absorptivity charateritcs are wavelength dependent, as is usually the case, then Kirchoff's law does not apply. For example, a black surface and a white surface exposed to sunlight will tend emit energy at about the same rate but they will absorb energy at very different rates. The result will be a relativity cooler white surface.
You know what I still don't get? Why's everyone acting like dividing a CPU into several separate cores is a good thing? It is a very good thing from a thermal point of view. Generally, speaking if the operating frequency of a processor is doubled, the power dissipation increases by a factor of six. On the other hand if you just added a second core, the power only increases by a factor of two.
Name ONE non-techie family member or friend of yours that has ever ripped a DVD to a computer for the "experience of legitimate users". My wife.
She made me rip a Thomas and Friends dvd because you could not fast forward to the menu. The five minutes of ads would make my two year old anxious, and cause my wife to throw a fit. I think everyday for a week she reminded me I need to 'fix' that DVD.
Not only did I take out the ads, I took out the menu so it starts right at the first story. They both love it.
I think your points are valid, but since teachers aren't experts on web browsing technology should they just close their mind to anything they don't understand?
The bigger question I am asking is, why cannot teachers learn from students everyone once a while? So maybe for the next assignment students could be given the option of using IE or Firefox depending on their comfort level.
He says look at the WTC, it collapsed because of the lack of redundancy.
What?
Seriously, the building was hit by 150,000 lb aircraft carrying 20,000 gallons of flammable liquid. It was obviously never designed to withstand that kind of structural complication.
However, for a minute lets say someone had enough foresight to add "resistance to impact from commercial aircraft" into the structural requirements. Why stop there? What about earthquakes, hurricanes, tornados, tsunamis, or meteorites?
Where do you draw line? How much cost can you tolerate?
It is not engineering that is overly concerned with cost to benefit ratios, that responsibility falls on management and/or accounting. If engineering comes up with two designs for a bridge, where one is under budget and lacks redundancy and the other is over budget and but incorporates redundancy, it is management or the customer that must decide what is most important.
Now some people may say that engineering has an ethical responsibility to build the best product, which may be true. But how does one do that, by quitting their job every time that don't get their way? Or by building the better a better product with the lesser budget, that is working for free?
While I agree that modern engineering has a lot less design tolerance. I think this is thanks to a better understanding of physics as well as better tools. So it is now possible to safely design bridge with a poor failure mode because we 'better' understand what drives the failure (I am not saying that poor failure modes are better).
In this case I think the inspection process is more suspect than actual design. I think everyone would agree that the design had areas of concern. But no design is perfect and all bridges will eventually fail. That is why they are inspected on regular bases. How is it that this bridge was inspected in the last few year and no critical issues were found? Doesn't that mean that a better inspection process is needed?
This is a classic example of badly conceived and designed IT implemented by indifferent lifer government contractors working off of ridiculous 2000-page requirement docs instead of, you know, what troopers actually need. But that 2,000 page requirement doc is how the military is suppose to force the contractor to provide what the soldier needs. If it is not in the requirements document how is the contractor suppose to know what satisfies the end user needs?
Slashdot Mirror
it's always a closed circuit. just depends on the timescale.
In thermodynamics a closed-system doesn't have any mass transfer across the system boundary. If the data center is using evaporative cooling which transfers water vapor (mass) out of the data center (system) it is an open system.
Whether the parents specific innovations are of interest to 'you' or not isn't the point. What he is talking about is innovations that would increase the feel of immersion in the game. Obviously, these will differ between people.
Ultimately, Duke3D created an immersive environmental like no other game of the time and most importantly it was fun. I remember putting dozens of pipe-bombs around a laser trip mine just because it was fun. A single trip mine alone would be enough to kill an enemy, but adding some pipe bombs just so Duke says "Let God Sort Em' Out" is classic.
Blowing up an enemy in another room while watching on the security camera or giving money to the strippers when my parents weren't watching, it was great. It was innovative and entertaining.
Jet-packs, subways, earth-quakes, novel weapons, snide comments, and more it really set the bar for all games that would follow. Kicking the final boss' Cyclopes eye through the goal post is just awesome. "Game Over" enough said.
And on our scale, absolute zero (0K) is -273C.
You metricpeans would think -273C is cold. Our scale goes all the way down to -460F, now that is cold!
We have a name for a mixture of water and carbon dioxide. It's called "seltzer water". With added impurities, it's sold as "soft drinks".
Mmmm ... Martian dust cola. Satisfies your body's need for hundreds of trace minerals.
Martian Dust Cola it's got electrolytes. It's what plants crave!
Something that might make it better is to implement a penalty when clicking that "flag as inappropriate" link. It should harm the person's votes, or be somehow detrimental (e.g. could only be done once a day and would also remove all your other votes). People will still self-sacrifice to remove something that's grossly inappropriate such as racial comments.
I was thinking the same thing. If there was a mod system similar to this site's, with a limited number of mod points. The cost modding down a question could be much higher than the cost of modding up a question.
Something like modding up a question costs 1 point, while modding down costs 3 points. If you only are given 5 points for a given duration, then it would become less effective to mod questions down. Also, in this case one would only be able to mod down a single comment, until the next mod cycle started.
FLAVOR FLAV !
I mean, unless the processor *needs* to be at LN2 temperature wouldn't it be more practical just to increase the flow rate of a water cooling system?
The processor is never going to be the same temperature as the liquid nitrogen (or any cooling median). As long as there is thermal resistance and/or heat being dissipated there will be some temperature difference.
You could just increase the flow rate of a water cooling system, but that is not without issues either. For example, pumping power increases exponentially with flow rate and heatsink geometry is typically optimal for a given flow rate.
Using the liquid nitrogen is just an easy way to get a high heat transfer rate by maximizing the temperature difference between the processor and cooling medium.
What I wonder is why people just put the liquid nitrogen is simple hollow copper tube. This isn't any different than a natural convection air heatsink. Why not create fins inside and try to maximize surface area and convection?
Since when is an increase of efficiency by 100% impossible?
For arguments sake, let's say that current wind turbines are 10% efficient. This new turbine is therefore 15% to 20% efficient.
Damnit!
I have been reading Slashdot all this time, and I only now realize that an "Insightful" post is one where you answer your own question :P
But the engine in a truck or bus is not fixed speed. It varies according to driving conditions, and there is a loss in efficiency due to the need to allow for the flexible load. If you use an engine merely for charging the battery then it can be a fixed speed, fixed load engine - I.e. it can run at peak efficiency whenever it is running, and the efficiency can be higher than a more flexible engine.
The point you make is spot on. However, why isn't more effort put into continuously/infinitely variable transmissions. Generally speaking the operating range of the engine is inversely proportional the number of gears in the transmission. The less gears the wider the engine operating range, the more gears the smaller the operating range.
With enough gears one can choose the operating speed independently of the actual road speed. In such a case wouldn't the engine be able to operate at the peak efficiency for any given engine load?
The point you make is spot on. However, why isn't more effort put into continuously/infinitely variable transmissions. Generally speaking the operating range of the engine is inversely proportional the number of gears in the transmission. The less gears the wider the engine operating range, the more gears the smaller the operating range.
With enough gears one can choose the operating speed independently of the actual road speed. In such a case wouldn't the engine be able to operate at the peak efficiency for any given engine load?
Err ... yikes. If that happens, your vehicle wasn't roadworthy to begin with, or the road conditions were so bad that applying the brakes wouldn't have been that much better.
I agree, and know for fact, engine braking can be done regularly and in a safe manner. But when done incorrectly or excessively it can and will upset the balance of the car. In a front wheel drive vehicle it may cause understeer but in a rear-wheel drive car it will cause oversteer.
I have locked up the rear-wheels in my car several times engine braking into a gear that requires excessive engine speed. Wheel lock can be reduced by rev-matching the engine speed for the lower gear but there is still a risk of sending more braking force to the tires than they can handle.
It has nothing do with the roadworthiness of the vehicle, it is basic vehicle dynamics.
Likewise in a RWD car with a manual transmission, running the engine to near red-line and then abruptly letting off the throttle can severally upset the balance of the car.
If it's being used to cool CPUs, I don't think it needs to be liquid at room temperature, since the area near most modern CPUs is considerably hotter than that! If your CPU is running at room temperature, you probably don't need much cooling (and if you do, you're going to need a much more elaborate system than merely one based on a liquid metal, since a passive heat-sink isn't going to take you anywhere below room temperature).
This may be true when the machine is running, but what about when it is initially started? As the processor begins to warm up the cooling medium will still be solid. Since solids are hard to pump the heat generated by the processor must be transported by conduction only. If the designer goes through the trouble of using a liquid cooler, it is probably safe to say that conduction only heat removal is not sufficient. So this presents some serious transient start-up issues.
However, with that said there are a lot design techniques that are applied to aerospace electronics but are not applied to commercial electronics. I am not sure that it really matters, does anyone really want their Dell to last for 15 years?
Word...send out the FCC Search and Destroy vessel to "drop the ****ing hammer"!
to date, which lead us to believe that the system works,
and that we should be building upon it. So we are taking
this step, as General Cartwright made abundantly clear last
week, not to test our anti-satellite capabilities. We did that in
1985. Been there, done that," a DOD spokesman said.
What happens if they try to shoot it down and miss? Especially after the successful Chinese demonstration. Would that drive other nations to push their military development programs even harder?
Our IT department has requested that everyone 'log-out' but leave their machines on so that they can be updated. Seems redundant since they also send out an email when new updates are available, and if the updates are not installed within a few days they eventually force the install. Personally, I just update when I see the email and turn my machine off at night mostly out of fear of a head crash and loss of data while I am away.
I think your points are valid, but since teachers aren't experts on web browsing technology should they just close their mind to anything they don't understand? The bigger question I am asking is, why cannot teachers learn from students everyone once a while? So maybe for the next assignment students could be given the option of using IE or Firefox depending on their comfort level.
Are sure that was written by an engineer?
He says look at the WTC, it collapsed because of the lack of redundancy.
What?
Seriously, the building was hit by 150,000 lb aircraft carrying 20,000 gallons of flammable liquid. It was obviously never designed to withstand that kind of structural complication.
However, for a minute lets say someone had enough foresight to add "resistance to impact from commercial aircraft" into the structural requirements. Why stop there? What about earthquakes, hurricanes, tornados, tsunamis, or meteorites?
Where do you draw line? How much cost can you tolerate?
It is not engineering that is overly concerned with cost to benefit ratios, that responsibility falls on management and/or accounting. If engineering comes up with two designs for a bridge, where one is under budget and lacks redundancy and the other is over budget and but incorporates redundancy, it is management or the customer that must decide what is most important.
Now some people may say that engineering has an ethical responsibility to build the best product, which may be true. But how does one do that, by quitting their job every time that don't get their way? Or by building the better a better product with the lesser budget, that is working for free?
While I agree that modern engineering has a lot less design tolerance. I think this is thanks to a better understanding of physics as well as better tools. So it is now possible to safely design bridge with a poor failure mode because we 'better' understand what drives the failure (I am not saying that poor failure modes are better).
In this case I think the inspection process is more suspect than actual design. I think everyone would agree that the design had areas of concern. But no design is perfect and all bridges will eventually fail. That is why they are inspected on regular bases. How is it that this bridge was inspected in the last few year and no critical issues were found? Doesn't that mean that a better inspection process is needed?