Air has an average relative molecular mass of about 29. Methane has a relative molecular mass of 16, ammonia 17 while hydrogen has a relative molecular mass of 2 and helium has a relative molecular mass of 4.
The effectiveness of a lifting gas is proportional to the difference between the relative molecular mass of the lifting gas and that of air. Calculating this figure gives us
Methane: 13 ammonia: 12 hydrogen: 27 helium: 25
In other words hydrogen or helium are about TWICE as effective as lifting gases as ammonia and methane.
The capaitors are connected in series regardless of how the voltage selector is set.
The ends of that series combination are connected to the AC supply by a diode bridge, they are also connected to the load. The switch is connected between the midpoint of the capacitors and one side of the incoming supply.
With the switch off (240V mode) the system acts as a normal bridge rectifier and the capacitors are charged in series during both half cycles.
With the switch on (120V mode) the system acts as a voltage doubling rectifier and charges one capacitor during each half cycle.
Either way you get about 300V DC across the capacitors which can be used to power a flyback converter to provide isolation and voltage conversion.
This design is cheap and works ok but connecting a rectifier-capacitor circuit directly to the mains results in a HORRIBLE power factor (even worse than connecting one via a transformer as the transformer limits the harmonic currents). As PCs have become both more common and more power hungry this horrible power factor has been deemed unacceptable (at least in europe) and all but the shittiest power supplies have moved to other designs
It should be noted: “relative to the private sector, the federal workforce is less than half the size it was back in the 1950s and 1960s”
Does the "federal workforce" reffered to in that article reffer only to people who work directly for the government? Afaict there has been a trend away from the government directly paying people to do work for them and towards the government paying contractors to do it.
AIUI Private carriers are legally prevented from effectively competing with the USPS on regular letter deliveries. Private carriers can take letters but unless they fall into one of a small set of exceptions (all designed to prevent companies operating under them from competing with the USPS's regular letter delivery service) they have to pay for the USPS service they didn't use.
I don't know specifically about SQL server but the trouble with csv is that there is no real standard. Various people have attempted to document it but that documentation came along long after the format was in widespread use.
Implementation of the CSV format as described in RFC 4180 allow a field to contain an arbitary sequence of bytes (which represent characters from some unknown but probablly ascii superset encoding) but there are plenty of ways to write a csv reader and/or writer such that a particular combination of writer and reader works must of the time but fails under certain conditions. I know i've ended up writing a csv parser from scratch so I can contol how it responds to broken input data (specifically unescaped quotes in the middle of fields).
There are two operating modes for WPA2, PSK and enterprise. The vast majority of wifi networks run in PSK mode.
In PSK mode all nodes (both end user and access point) use a shared secret key. Anyone with thatkey can decrypt any packet, spoof any user etc. So you had better make sure only truested devices have the key.
In enterprise mode each end user has their own login and the system is supposed to protect the users from each other as well as from outsiders. The article you linked was about a flaw in enterprise mode that effectively degraded security to equivilent to PSK mode. It's a fairly serious issue for large enterprise deployments but not something that should be a concern for end users.
While there are some areas in the UK that are nearly 100% electrified and where there aren't many out of area trains much of the UK has a mixture of electrified and non-electrified lines and many trains run between areas. The manchester to Bournemouth service for example runs along electrified lines for much of it's journey (afaict the route is overhead at least from manchester to coventry and third rail from baisingstoke to bournmouth) but there is a section in the middle which is not electrified with either system.
For some reason trains that can switch between locally generated electricty and the two common electrification systems in the UK don't seem to exist and even trains that can run on two of the three haven't really caught on and most trains no longer have seperate locomotives. So routes like the one mentioned above are run with diesel trains all the way.
The line through my local station is overhead electrified but it only sees one electric train each way a day now (it used to see more before they reorganised the timetable a few years back) because the route structure means that nearly all of the trains have portions of their journey on non-electrified lines (to either buxton, preston or sheffield).
If they want to increase the proportion of the fleet that runs on electricity there is much lower hanging fruit IMO in introducing trains that can switch between third rail, overhead and diesel than in crazy expensive battery systems.
Intel briefly sold a discrete gpu back in the early days of agp but it was a failure in the market and since then they seem to have decided to sell their GPU techology as an integrated component of their platform (previously in the northbridge, now in the CPU).
Currently, when I look in store I really only see one vendor.
Your stores must suck, both NVIDIA and ATI are readilly available round here.
The problem is most food products do not list the source of every ingredient so unless all you ever buy are raw unblended food products (typical "normal" honey is blended) you are probablly eating stuff from china without knowing it.
And don't forget that there are plenty of people out there who are quite prepared to lie. So even if they did mandate that food products were printed with the country of origin of every ingrediant you would have very little certainty that the list was correct.
The difficult adjusts to the block discovery rate such that the supply of bitcoin is roughly fixed. ASIC miners won't have much impact on total bitcoint production but they will dramatically change who gets that production.
So it really depends on how the willingness to sell differs between the old GPU/FPGA miners and the new ASIC miners.
I suspect the answer is as long as not too many people know they exist:/ Theres also teredo and 6to4 (though they may have problems with overloaded or even discontinued relays if they get too popular).
And it's basically irrelevent on x86/x64 linux too. Afaict when software supports ES it generally has a compile time switch between regular opengl and opengl ES. Pretty much all GPUs seen in x86 systems support regular opengl while only a subset of them support ES so the sane thing for a distro to do is to use regular opengl for the x86/x64 builds of their software and only build for ES on architectures where ES only GPUs are common.
The thing is a progress bar is pretty hard to fake convincingly, if your bar always progresses at the same rate and then freezes at a fixed point it's going to get noticed pretty quick. A spinner or similar indicator is much easier to fake convincingly and if something is easy to fake convincingly there will always be the suspicion that it is fake..
Heck windows kinda institutionalised faking such things by including animated icon support in the OS itself and including an icon set where the hourglass was animated.
I have a box in my office built out of intel workstation parts* (which are pretty much intel server parts with some minor tweaks) and i've found that while it does get quieter at low load the sound actually gets more annoying because it pulsates.
Mind you on the rare occasions when the fans do spool up to full blast (the only time they seem to do this now is during POST but when I first built the thing it ran them on full blast continuously, it took me a while how to figure out how to tell the board what case it was in) it does sound like a vaccum cleaner.
*IIRC the only parts in the box that were not from Intel were the ram and the hard drives.
The length and width dimensions of the pcb are exactly credit card dimensions.
No they aren't (despite the raspberry pi foundation's faq saying for a while they were), the PCB is roughly the same length as a credit card but a couple of mm wider.
Add the connector overhangs and overall the Pi is slightly longer than a credit card, slightly wider than a credit card and MANY MANY times thicker than a credit card.
I wonder if Broadcom now have a more powerful SoC that could be used in a next generation RPi.
I'm sure they do and assuming the Pi continues to be a success i'm sure that we will eventually see a second generation of Pi *. However it makes no sense for the foundation to do that right now. It would fragment the community and take the foundations resources away from other things like making the education push and getting the camera board finalised and released.
* Which would pretty much be a redesign from scratch afaict.
I have to say i've generally had a pretty good experiance with my bytemark vm. Performance was a bit shaky at first but it seems to have improved a lot over the years and iptables has always been available (the machine started out as UML TT, then moved to UML SKAS and is now on KVM, I think it may have been on XEN for a while too but I don't remember for sure).
A dedicated server even from a cheap provider would cost nearly twice as much
Bandwidth? Do bits just appear at the NIC via some temporal quantum process (for free!)?
No but most home connections aren't metered and most vps packages come with a fair chunk of bandwidth. So this is an issue in the feasibility side but unlikely to be part of the financial calculations.
Domain name (most hosting and a few VPS will include the first domain name).
Most vps services don't and even if they did IMO only idiots buy their domain name from the same people they buy their hosting from.
Is he even allowed via TOS to put a server on a home connection? How much extra is a dedicated IP?
Depends where he lives, round here servers are not usually banned and most customers get a public IP. The IP isn't static but that is something you can live with.
There are people out there who can interchange time and money pretty freely. E.G. self employed tradesmen who have more clients wanting work than time to do that work and workers who work at a place that pays overtime and generally has it available.
However I belive in most situations this is the exception not the rule. People have a certain ammount of free time and a certain ammount of money each month and can't easilly trade one for the other.
Open standards and DRM are fundamentally incompatible. If you know how to decode something to display it to the user you also know how to decode it and save the results of that decoding to a file. Therefore any standard that includes drm will either be trivially broken (see conventional pdf "usage restrictions") or not truely open.
But surely we could have launched those particle accelerators using the spacecraft that would have resulted from project orion had it not been cancelled.
On minor nit though, debian don't have "a server called nonfree". Despite non-free not being an official part of debian it's managed by the same infrastructure and distributed through the same mirror network. Dependencies in packages in non-free can impact the migration to testing of free packages and mirrors that don't want to carry non-free have to explicitly exclude it.
Slashdot Mirror
2. This was a story about British farmers and you are talking about the US government and American companies.
Did you actually RTFA? it started off about british farmers but it quickly shifted to the USA.
Air has an average relative molecular mass of about 29. Methane has a relative molecular mass of 16, ammonia 17 while hydrogen has a relative molecular mass of 2 and helium has a relative molecular mass of 4.
The effectiveness of a lifting gas is proportional to the difference between the relative molecular mass of the lifting gas and that of air. Calculating this figure gives us
Methane: 13
ammonia: 12
hydrogen: 27
helium: 25
In other words hydrogen or helium are about TWICE as effective as lifting gases as ammonia and methane.
umm 99.9% is about 0.73 hours per month, not 7-8 hours per month.
The capaitors are connected in series regardless of how the voltage selector is set.
The ends of that series combination are connected to the AC supply by a diode bridge, they are also connected to the load. The switch is connected between the midpoint of the capacitors and one side of the incoming supply.
With the switch off (240V mode) the system acts as a normal bridge rectifier and the capacitors are charged in series during both half cycles.
With the switch on (120V mode) the system acts as a voltage doubling rectifier and charges one capacitor during each half cycle.
Either way you get about 300V DC across the capacitors which can be used to power a flyback converter to provide isolation and voltage conversion.
This design is cheap and works ok but connecting a rectifier-capacitor circuit directly to the mains results in a HORRIBLE power factor (even worse than connecting one via a transformer as the transformer limits the harmonic currents). As PCs have become both more common and more power hungry this horrible power factor has been deemed unacceptable (at least in europe) and all but the shittiest power supplies have moved to other designs
It should be noted: “relative to the private sector, the federal workforce is less than half the size it was back in the 1950s and 1960s”
Does the "federal workforce" reffered to in that article reffer only to people who work directly for the government? Afaict there has been a trend away from the government directly paying people to do work for them and towards the government paying contractors to do it.
AIUI Private carriers are legally prevented from effectively competing with the USPS on regular letter deliveries. Private carriers can take letters but unless they fall into one of a small set of exceptions (all designed to prevent companies operating under them from competing with the USPS's regular letter delivery service) they have to pay for the USPS service they didn't use.
I don't know specifically about SQL server but the trouble with csv is that there is no real standard. Various people have attempted to document it but that documentation came along long after the format was in widespread use.
Implementation of the CSV format as described in RFC 4180 allow a field to contain an arbitary sequence of bytes (which represent characters from some unknown but probablly ascii superset encoding) but there are plenty of ways to write a csv reader and/or writer such that a particular combination of writer and reader works must of the time but fails under certain conditions. I know i've ended up writing a csv parser from scratch so I can contol how it responds to broken input data (specifically unescaped quotes in the middle of fields).
There are two operating modes for WPA2, PSK and enterprise. The vast majority of wifi networks run in PSK mode.
In PSK mode all nodes (both end user and access point) use a shared secret key. Anyone with thatkey can decrypt any packet, spoof any user etc. So you had better make sure only truested devices have the key.
In enterprise mode each end user has their own login and the system is supposed to protect the users from each other as well as from outsiders. The article you linked was about a flaw in enterprise mode that effectively degraded security to equivilent to PSK mode. It's a fairly serious issue for large enterprise deployments but not something that should be a concern for end users.
While there are some areas in the UK that are nearly 100% electrified and where there aren't many out of area trains much of the UK has a mixture of electrified and non-electrified lines and many trains run between areas. The manchester to Bournemouth service for example runs along electrified lines for much of it's journey (afaict the route is overhead at least from manchester to coventry and third rail from baisingstoke to bournmouth) but there is a section in the middle which is not electrified with either system.
For some reason trains that can switch between locally generated electricty and the two common electrification systems in the UK don't seem to exist and even trains that can run on two of the three haven't really caught on and most trains no longer have seperate locomotives. So routes like the one mentioned above are run with diesel trains all the way.
The line through my local station is overhead electrified but it only sees one electric train each way a day now (it used to see more before they reorganised the timetable a few years back) because the route structure means that nearly all of the trains have portions of their journey on non-electrified lines (to either buxton, preston or sheffield).
If they want to increase the proportion of the fleet that runs on electricity there is much lower hanging fruit IMO in introducing trains that can switch between third rail, overhead and diesel than in crazy expensive battery systems.
can I buy an intel video card yet?
Intel briefly sold a discrete gpu back in the early days of agp but it was a failure in the market and since then they seem to have decided to sell their GPU techology as an integrated component of their platform (previously in the northbridge, now in the CPU).
Currently, when I look in store I really only see one vendor.
Your stores must suck, both NVIDIA and ATI are readilly available round here.
The problem is most food products do not list the source of every ingredient so unless all you ever buy are raw unblended food products (typical "normal" honey is blended) you are probablly eating stuff from china without knowing it.
And don't forget that there are plenty of people out there who are quite prepared to lie. So even if they did mandate that food products were printed with the country of origin of every ingrediant you would have very little certainty that the list was correct.
The difficult adjusts to the block discovery rate such that the supply of bitcoin is roughly fixed. ASIC miners won't have much impact on total bitcoint production but they will dramatically change who gets that production.
So it really depends on how the willingness to sell differs between the old GPU/FPGA miners and the new ASIC miners.
I suspect the answer is as long as not too many people know they exist :/ Theres also teredo and 6to4 (though they may have problems with overloaded or even discontinued relays if they get too popular).
And it's basically irrelevent on x86/x64 linux too. Afaict when software supports ES it generally has a compile time switch between regular opengl and opengl ES. Pretty much all GPUs seen in x86 systems support regular opengl while only a subset of them support ES so the sane thing for a distro to do is to use regular opengl for the x86/x64 builds of their software and only build for ES on architectures where ES only GPUs are common.
Sure it should.
The thing is a progress bar is pretty hard to fake convincingly, if your bar always progresses at the same rate and then freezes at a fixed point it's going to get noticed pretty quick. A spinner or similar indicator is much easier to fake convincingly and if something is easy to fake convincingly there will always be the suspicion that it is fake..
Heck windows kinda institutionalised faking such things by including animated icon support in the OS itself and including an icon set where the hourglass was animated.
I have a box in my office built out of intel workstation parts* (which are pretty much intel server parts with some minor tweaks) and i've found that while it does get quieter at low load the sound actually gets more annoying because it pulsates.
Mind you on the rare occasions when the fans do spool up to full blast (the only time they seem to do this now is during POST but when I first built the thing it ran them on full blast continuously, it took me a while how to figure out how to tell the board what case it was in) it does sound like a vaccum cleaner.
*IIRC the only parts in the box that were not from Intel were the ram and the hard drives.
The length and width dimensions of the pcb are exactly credit card dimensions.
No they aren't (despite the raspberry pi foundation's faq saying for a while they were), the PCB is roughly the same length as a credit card but a couple of mm wider.
Add the connector overhangs and overall the Pi is slightly longer than a credit card, slightly wider than a credit card and MANY MANY times thicker than a credit card.
I wonder if Broadcom now have a more powerful SoC that could be used in a next generation RPi.
I'm sure they do and assuming the Pi continues to be a success i'm sure that we will eventually see a second generation of Pi *. However it makes no sense for the foundation to do that right now. It would fragment the community and take the foundations resources away from other things like making the education push and getting the camera board finalised and released.
* Which would pretty much be a redesign from scratch afaict.
I have to say i've generally had a pretty good experiance with my bytemark vm. Performance was a bit shaky at first but it seems to have improved a lot over the years and iptables has always been available (the machine started out as UML TT, then moved to UML SKAS and is now on KVM, I think it may have been on XEN for a while too but I don't remember for sure).
A dedicated server even from a cheap provider would cost nearly twice as much
Bandwidth? Do bits just appear at the NIC via some temporal quantum process (for free!)?
No but most home connections aren't metered and most vps packages come with a fair chunk of bandwidth. So this is an issue in the feasibility side but unlikely to be part of the financial calculations.
Domain name (most hosting and a few VPS will include the first domain name).
Most vps services don't and even if they did IMO only idiots buy their domain name from the same people they buy their hosting from.
Is he even allowed via TOS to put a server on a home connection? How much extra is a dedicated IP?
Depends where he lives, round here servers are not usually banned and most customers get a public IP. The IP isn't static but that is something you can live with.
they'd probably get a cheap LOUD (jet engine fans) server,
From the article it's pretty clear this is a repurposed desktop so probablly neither super-quiet or "jet engine loud".
As long as it's not in a room where someone sleeps I doubt noise will be a problem.
You are also ignoring the value of your time
There are people out there who can interchange time and money pretty freely. E.G. self employed tradesmen who have more clients wanting work than time to do that work and workers who work at a place that pays overtime and generally has it available.
However I belive in most situations this is the exception not the rule. People have a certain ammount of free time and a certain ammount of money each month and can't easilly trade one for the other.
Open standards and DRM are fundamentally incompatible. If you know how to decode something to display it to the user you also know how to decode it and save the results of that decoding to a file. Therefore any standard that includes drm will either be trivially broken (see conventional pdf "usage restrictions") or not truely open.
But surely we could have launched those particle accelerators using the spacecraft that would have resulted from project orion had it not been cancelled.
I agree with your post generally.
On minor nit though, debian don't have "a server called nonfree". Despite non-free not being an official part of debian it's managed by the same infrastructure and distributed through the same mirror network. Dependencies in packages in non-free can impact the migration to testing of free packages and mirrors that don't want to carry non-free have to explicitly exclude it.