Yellow underarm stains result from the combination of aluminum/zirconium-based antiperspirants and fatty compounds in sweat. I'm surprised to hear that TSP, as an alkaline compound (pH 12 in moderate concentrations) can remove them.
There are several patents for products to deal with those stains, and essentially, the approach is to use fairly strong acids in combination with nonionic surfactants. Vinegar is too weak; we're talking about soaking the fabric in 10% hydrochloric acid. AFAIK there is one such product on the market, but not where I live. Anyway, the chemical action of acids is the opposite of that of alkaline compounds; hence my surprise.
That's nice from a cryptographic point of view, but in practice, voter Bob would have a letter from government Alice with the passwords that show the real and the fake votes, and a password recovery system. Carol would just demand to see the letter or tell Bob to reset her passwords.
The period of a period of open vote changes is interesting, but has a different problem, which is common to all e-voting systems: Carol can pressure Bob to provide the credentials for voting and do the voting herself.
Anyway, electronic voting systems give a lot of power to people who handle the software, i.e. if Alice is malicious. You'd better hope that none of them is bribed or blackmailed into changing the election results. A voting error of 1% today may be acceptable. But the system must also work in the future after you vote in a corrupt government.
Your approach requires dedication and a good memory, for everyone. Good for you, but the burden should be on the banks and providers of payment terminals.
Most ATMs here in the Netherlands show a picture on the screen of what the card slot (and anti-tamper protrusions) should look like. That's a cheap and effective solution. A bigger problem used to be the payment terminals in stores and train stations, of which there are too many models to remember what they should look like. But with the transition to chip/EMV a few years ago, we no longer swipe our card, eliminating the risk of magstripe skimming.
And to deter magstripe skimming even more, at least one bank blocks the use of their debit cards outside Western Europe (i.e. non-EMV countries), unless the customer specifically requests a temporary unblock for a specific country.
"There are at least a few bits which we don't have the complete sources for. For example all the devices with 802.11ac chips in them."
But you know how those bits interact with the rest of the router. What kind of permissions does the radio firmware have that could be used for nefarious purposes? Serious question. Would nefarious firmware be able to leak AES keys or wifi passwords? Or read/write memory in the router OS?
Battery storage for a 12,000-people town for 7 minutes is not a viable system to smooth out supply/demand mismatches over the course of days or weeks. In the Fairbanks case, it's just to allow the diesel generators to spin up. I think that in order to make wind/PV viable, we need to have an enormous amount of idle conventional production capacity available. Batteries and such can be used to bridge the hours needed to spin up the idle capacity.
I don't see a major trans-continental transport capacity happening, nor a substantial flexibility of the demand over several days. At least, I'm willing to postpone the laundry by a day or two, but not by a week. Nor do I see industry shutting down their operations for a week just because electricity is temporarily too expensive.
"The Tesla lithium battery is supposed to be more efficient than the lead-acid battery in the charge-discharge cycle?"
Indeed. Otherwise you would never be able to recharge 50% of 85 kWh in 20 minutes in a stationary car without boiling the batteries. For the Tesla, 92% round-trip efficiency seems to be a widely quoted value.
"When sound waves of nearly equal frequencies interfere we hear a beat frequency which is the difference between the two frequencies."
Unfortunately, that only works if the sound waves by themselves are audible. It won't convert supersonic sound to audible sound, unless the original amplitude is so large that you get significant nonlinear effects (that's essentially how a radio receiver works).
"passenger vehicles utilizing diesel fuel make less diesel fuel available for trains and trucks."
You talk like a given amount of crude oil will produce diesel and gasoline in a fixed ratio. Nope; oil refineries do not just separate, but also convert hydrocarbons from crude oil. If anything, it's the other way around: gasoline needs to have a specific boiling point and knock resistance, while diesel is essentially any combustible liquid that has roughly the right viscosity for the nozzles and pumps. You can even run an unmodified diesel car on sunflower oil (not recommended for long-term use though). It's more work to convert/purify crude tino gasoline than into diesel.
You make it sound like 'suitable for base load' is a good thing. Base load is the part of the power generation capacity that never needs to be throttled. Nuclear is good for that because nuclear (and coal as well) are very slow to respond to changes in demand.
What is really needed is something that can adapt rapidly to changes in demand or compensate for intermittent PV and wind production. At present, those are gas turbines and hydro. Other approaches are (battery) storage and letting the demand follow the supply in stead of the other way around. How well those alternatives work out in combination with long (>36 hour) periods of low-wind, low-sun conditions remains to be seen.
DVD subtitles are low-res, blocky bitmaps that don't scale nicely. Tghat's why I'd like to have them in ascii or utf-8 format. Sorting out and labeling the tracks of a dvd with a few 20-minute episodes of a series, trailers, and special features is not mentally challenging, but it still takes time and the balance of that time versus sitting through the unskippable parts for the two times that I might re-watch that dvd in the future tips in favor of not ripping.
"My gas tank is 14 gallons = 472 kWh... Compare that to Tesla's 85 kWh battery"
Apples and oranges. You count heat of combustion for your fuel tank. Of that energy, about 17% (80 kWh) will actually reach the wheels. And that's not counting regenerative braking and the low air resistance of a Tesla.
It's also not counting losses in a power plant, windmill, or PV installation, of course.
Where are you from? I'm curious why you didn't mention the behavior of bicyclists, something that drivers usually do over here (NL). And I know other European countries towards the South/East that are much worse.
With bikes, non-adherence to rules (in particular red lights) does improve flow. I've seen 200-meter bike queues while the police was visibly monitoring an intersection during rush hour...
BTW I don't deny that there are crazy people on the road, especially around a city like Amsterdam.
With medical data it's a pain to provide raw data and still guarantee anonymity of the test subjects.
In genetics, the data is fairly standardized: it's a list of base pairs and the method to get the list from a DNA sample is standardized. However, in fields where data representation and handling are not standardized, it will be a major effort to document the data and metadata representation. For experimental physics, the raw data will only make sense in combination with the hand-written lab notes, hardware details which could be scattered over years of lab notes or that are, only in the head of the Ph.D. student. I have exchanged raw data on some occasions, both on the giving and receiving side. It usually requires extensive oral explanation, and sometimes, the details can't be remembered.
And what purpose does it serve? In 99% of the papers, not even the referee will be willing to sift through the raw data, which may have taken months of analysis, whereas the referee can only spend an hour or two.
Can Handbrake handle subtitles and dvd chapter/title formats well? A while ago I considered ripping my dvd collection. Tried several Linux rippers and gave up after the third dvd.
Converting subtitles to text by OCR'ing low-res subtitle bitmaps Wasa dl5a5 fer... Online subtitle rips were out of sync due to deleted scenes or 24/25 fps mismatches. Figuring out which chapters/titles correspond to the main feature film or episodes and which ones were trailers and copyright notices was also a pain. I also recall annoyances with deinterlacing and 4:3 versus 16:9 formats. Ripping an audio cd is infinitely more easy.
I decided to stick with just finding the dvd if I wanted to rewatch a movie and sit through the silly unskippable parts.
"... that more than a tiny fraction of priests don't believe in the religion they preach (to the extent that it would be fair to call them deliberately deceptive) then you're an..."
Depends on the definitions of 'tiny' and 'believe'. I know a protestant theologist who used to teach priests-to-be and who became a priest himself a few years ago. At least, they teach the students about the historical background of the Bible (i.e., it was definitely not written by God, nor do scholars believe that a lot of what's in it really happened). Basically, they teach the students that God as described in the Bible does not exist. There are some true-believer students who memorize it just so that they pass the exams, but most of the students get the point.
So when priests preach, I suppose that "God" in their mind is a metaphor for ideas about life, even though it they know that it means something different to many churchgoers. Is that deception?
Late response... Nitrogen can be fixed from the air by legumes. However, plants deplete the soil of phosphorus, potassium, and some calcium and sulfur. If you eat the plants and animals eating from your soils and remove those nutrients via the toilet or by throwing out the bones and waste from butchering, you have a cycle that is unsustainable in the long term. You can transfer the problem to whomever is growing the food for those animals, but those minerals have to come from somewhere - either from fertilizer or by grinding down rocks.
I suspect that you misremember or that the one who told you this was lying. At least, I can't find any information that confirms this. To the contrary, this book uses the Vietnam war as evidence for the importance of treatment for survival.
I think the text-centric nature of slashdot is a big plus. I wouldn't want it to turn into yet another web forum with inline images, huge sigs, animated smileys, and people writing like 14-year-olds.
When I have a keyboard, I don't mind the html markup either. But on a phone, it's a pain.
"... why we have a "cold and flu" season: once we stop getting sunshine, everyone's D levels drop low enough to depress our immune system."
Citation needed. At least Wikipedia states: "Beyond its use to prevent osteomalacia or rickets, the evidence for other health effects of vitamin D supplementation in the general population is inconsistent.[5][6]"
"no reason to upgrade the code. In fact, I'd prefer if they reverted to one of the older versions from earlier years that has fewer "Web 2.0" stunts and just serves up the damned text."
Here are som reasons to upgrade:
* support unicode, * get workable access to preferences (if you enable "classic mode?, all kind of stuff breaks, including getting back to default D2 mode.). * Get a decent mobile view (Can't access it when logged in and it's unworkable anyway on my quad-core, 2 GB RAM phone). That's why I maintain avantslash (see signature). * Support https.
Soylentnews forked the last public release of slashcode and did a pretty good job. Unfortunately the community is too small to get good discussions going on technical subjects.
P.S. in case you're wondering why speed is an issue: the sum of molecular thermal velocity and bulk velocity at the top of the tower must be higher than the escape velocity at that altitude. Escape velocity drops only slowly with altitude: you'd need a tower of10 times the radius of Venus to get the escape velocity down to reasonable thermal velocities. Otherwise you'd need to heat the gas in the tower to ~5000 K, which is not possible using solar energy concentrators because the sun itself is about that temperature.
That's exactly why it won't work. Why does warm gas rise? Because there is cooler, heavier gas around that takes its place. The maximum upward pressure is therefore equal to the atmospheric pressure, which will never be able to push the speed to much above Mach 1.
"solar chimney - basically a giant funnel-shaped greenhouse floating on Venus. The gas accelerates faster and faster the further it rises into the funnel.... velocities of tens of thousands of meters per second could be reached"
I highly doubt that, but maybe I'm missing something. The upward force is buoyancy force from the existing lower-temperature atmosphere. I don't see how that would ever give enough pressure to reach evensupersonic speeds, never mind the escape velocity that is 50x higher than that.
Slashdot Mirror
Yellow underarm stains result from the combination of aluminum/zirconium-based antiperspirants and fatty compounds in sweat. I'm surprised to hear that TSP, as an alkaline compound (pH 12 in moderate concentrations) can remove them.
There are several patents for products to deal with those stains, and essentially, the approach is to use fairly strong acids in combination with nonionic surfactants. Vinegar is too weak; we're talking about soaking the fabric in 10% hydrochloric acid. AFAIK there is one such product on the market, but not where I live. Anyway, the chemical action of acids is the opposite of that of alkaline compounds; hence my surprise.
That's nice from a cryptographic point of view, but in practice, voter Bob would have a letter from government Alice with the passwords that show the real and the fake votes, and a password recovery system. Carol would just demand to see the letter or tell Bob to reset her passwords.
The period of a period of open vote changes is interesting, but has a different problem, which is common to all e-voting systems: Carol can pressure Bob to provide the credentials for voting and do the voting herself.
Anyway, electronic voting systems give a lot of power to people who handle the software, i.e. if Alice is malicious. You'd better hope that none of them is bribed or blackmailed into changing the election results. A voting error of 1% today may be acceptable. But the system must also work in the future after you vote in a corrupt government.
Your approach requires dedication and a good memory, for everyone. Good for you, but the burden should be on the banks and providers of payment terminals.
Most ATMs here in the Netherlands show a picture on the screen of what the card slot (and anti-tamper protrusions) should look like. That's a cheap and effective solution. A bigger problem used to be the payment terminals in stores and train stations, of which there are too many models to remember what they should look like. But with the transition to chip/EMV a few years ago, we no longer swipe our card, eliminating the risk of magstripe skimming.
And to deter magstripe skimming even more, at least one bank blocks the use of their debit cards outside Western Europe (i.e. non-EMV countries), unless the customer specifically requests a temporary unblock for a specific country.
"There are at least a few bits which we don't have the complete sources for. For example all the devices with 802.11ac chips in them."
But you know how those bits interact with the rest of the router. What kind of permissions does the radio firmware have that could be used for nefarious purposes? Serious question. Would nefarious firmware be able to leak AES keys or wifi passwords? Or read/write memory in the router OS?
I don't see a major trans-continental transport capacity happening, nor a substantial flexibility of the demand over several days. At least, I'm willing to postpone the laundry by a day or two, but not by a week. Nor do I see industry shutting down their operations for a week just because electricity is temporarily too expensive.
Indeed. Otherwise you would never be able to recharge 50% of 85 kWh in 20 minutes in a stationary car without boiling the batteries. For the Tesla, 92% round-trip efficiency seems to be a widely quoted value.
"When sound waves of nearly equal frequencies interfere we hear a beat frequency which is the difference between the two frequencies."
Unfortunately, that only works if the sound waves by themselves are audible. It won't convert supersonic sound to audible sound, unless the original amplitude is so large that you get significant nonlinear effects (that's essentially how a radio receiver works).
"passenger vehicles utilizing diesel fuel make less diesel fuel available for trains and trucks."
You talk like a given amount of crude oil will produce diesel and gasoline in a fixed ratio. Nope; oil refineries do not just separate, but also convert hydrocarbons from crude oil. If anything, it's the other way around: gasoline needs to have a specific boiling point and knock resistance, while diesel is essentially any combustible liquid that has roughly the right viscosity for the nozzles and pumps. You can even run an unmodified diesel car on sunflower oil (not recommended for long-term use though). It's more work to convert/purify crude tino gasoline than into diesel.
You make it sound like 'suitable for base load' is a good thing. Base load is the part of the power generation capacity that never needs to be throttled. Nuclear is good for that because nuclear (and coal as well) are very slow to respond to changes in demand.
What is really needed is something that can adapt rapidly to changes in demand or compensate for intermittent PV and wind production. At present, those are gas turbines and hydro. Other approaches are (battery) storage and letting the demand follow the supply in stead of the other way around. How well those alternatives work out in combination with long (>36 hour) periods of low-wind, low-sun conditions remains to be seen.
DVD subtitles are low-res, blocky bitmaps that don't scale nicely. Tghat's why I'd like to have them in ascii or utf-8 format. Sorting out and labeling the tracks of a dvd with a few 20-minute episodes of a series, trailers, and special features is not mentally challenging, but it still takes time and the balance of that time versus sitting through the unskippable parts for the two times that I might re-watch that dvd in the future tips in favor of not ripping.
"My gas tank is 14 gallons = 472 kWh ... Compare that to Tesla's 85 kWh battery"
Apples and oranges. You count heat of combustion for your fuel tank. Of that energy, about 17% (80 kWh) will actually reach the wheels. And that's not counting regenerative braking and the low air resistance of a Tesla.
It's also not counting losses in a power plant, windmill, or PV installation, of course.
https://en.wikipedia.org/wiki/...
"Drivers in Holland are frigging dreadful"
Where are you from? I'm curious why you didn't mention the behavior of bicyclists, something that drivers usually do over here (NL). And I know other European countries towards the South/East that are much worse.
With bikes, non-adherence to rules (in particular red lights) does improve flow. I've seen 200-meter bike queues while the police was visibly monitoring an intersection during rush hour...
BTW I don't deny that there are crazy people on the road, especially around a city like Amsterdam.
With medical data it's a pain to provide raw data and still guarantee anonymity of the test subjects.
In genetics, the data is fairly standardized: it's a list of base pairs and the method to get the list from a DNA sample is standardized. However, in fields where data representation and handling are not standardized, it will be a major effort to document the data and metadata representation. For experimental physics, the raw data will only make sense in combination with the hand-written lab notes, hardware details which could be scattered over years of lab notes or that are, only in the head of the Ph.D. student. I have exchanged raw data on some occasions, both on the giving and receiving side. It usually requires extensive oral explanation, and sometimes, the details can't be remembered.
And what purpose does it serve? In 99% of the papers, not even the referee will be willing to sift through the raw data, which may have taken months of analysis, whereas the referee can only spend an hour or two.
Can Handbrake handle subtitles and dvd chapter/title formats well? A while ago I considered ripping my dvd collection. Tried several Linux rippers and gave up after the third dvd.
Converting subtitles to text by OCR'ing low-res subtitle bitmaps Wasa dl5a5 fer... Online subtitle rips were out of sync due to deleted scenes or 24/25 fps mismatches. Figuring out which chapters/titles correspond to the main feature film or episodes and which ones were trailers and copyright notices was also a pain. I also recall annoyances with deinterlacing and 4:3 versus 16:9 formats. Ripping an audio cd is infinitely more easy.
I decided to stick with just finding the dvd if I wanted to rewatch a movie and sit through the silly unskippable parts.
"... that more than a tiny fraction of priests don't believe in the religion they preach (to the extent that it would be fair to call them deliberately deceptive) then you're an..."
Depends on the definitions of 'tiny' and 'believe'. I know a protestant theologist who used to teach priests-to-be and who became a priest himself a few years ago. At least, they teach the students about the historical background of the Bible (i.e., it was definitely not written by God, nor do scholars believe that a lot of what's in it really happened). Basically, they teach the students that God as described in the Bible does not exist. There are some true-believer students who memorize it just so that they pass the exams, but most of the students get the point.
So when priests preach, I suppose that "God" in their mind is a metaphor for ideas about life, even though it they know that it means something different to many churchgoers. Is that deception?
Late response... Nitrogen can be fixed from the air by legumes. However, plants deplete the soil of phosphorus, potassium, and some calcium and sulfur. If you eat the plants and animals eating from your soils and remove those nutrients via the toilet or by throwing out the bones and waste from butchering, you have a cycle that is unsustainable in the long term. You can transfer the problem to whomever is growing the food for those animals, but those minerals have to come from somewhere - either from fertilizer or by grinding down rocks.
I suspect that you misremember or that the one who told you this was lying. At least, I can't find any information that confirms this. To the contrary, this book uses the Vietnam war as evidence for the importance of treatment for survival.
https://books.google.nl/books?...
I think the text-centric nature of slashdot is a big plus. I wouldn't want it to turn into yet another web forum with inline images, huge sigs, animated smileys, and people writing like 14-year-olds. When I have a keyboard, I don't mind the html markup either. But on a phone, it's a pain.
"... why we have a "cold and flu" season: once we stop getting sunshine, everyone's D levels drop low enough to depress our immune system."
Citation needed. At least Wikipedia states: "Beyond its use to prevent osteomalacia or rickets, the evidence for other health effects of vitamin D supplementation in the general population is inconsistent.[5][6]"
"no reason to upgrade the code. In fact, I'd prefer if they reverted to one of the older versions from earlier years that has fewer "Web 2.0" stunts and just serves up the damned text."
Here are som reasons to upgrade:
* support unicode,
* get workable access to preferences (if you enable "classic mode?, all kind of stuff breaks, including getting back to default D2 mode.).
* Get a decent mobile view (Can't access it when logged in and it's unworkable anyway on my quad-core, 2 GB RAM phone). That's why I maintain avantslash (see signature).
* Support https.
Soylentnews forked the last public release of slashcode and did a pretty good job. Unfortunately the community is too small to get good discussions going on technical subjects.
"I use Python, but I have never looked at a Python tutorial. The language is simple and the syntax is obvious."
That's how I started as well, but it resulted in horrible C-like constructs, like literal translations of
for (i=m; i<n; ++i) {}
with while and if. And it took a while to figure out how the lack of pointers and the murable/immutable object distinction work in practice.
P.S. in case you're wondering why speed is an issue: the sum of molecular thermal velocity and bulk velocity at the top of the tower must be higher than the escape velocity at that altitude. Escape velocity drops only slowly with altitude: you'd need a tower of10 times the radius of Venus to get the escape velocity down to reasonable thermal velocities. Otherwise you'd need to heat the gas in the tower to ~5000 K, which is not possible using solar energy concentrators because the sun itself is about that temperature.
That's exactly why it won't work. Why does warm gas rise? Because there is cooler, heavier gas around that takes its place. The maximum upward pressure is therefore equal to the atmospheric pressure, which will never be able to push the speed to much above Mach 1.
When you garden, you still need to buy fertilizer, or that biomass production will stop after a season or two.
"solar chimney - basically a giant funnel-shaped greenhouse floating on Venus. The gas accelerates faster and faster the further it rises into the funnel.... velocities of tens of thousands of meters per second could be reached"
I highly doubt that, but maybe I'm missing something. The upward force is buoyancy force from the existing lower-temperature atmosphere. I don't see how that would ever give enough pressure to reach evensupersonic speeds, never mind the escape velocity that is 50x higher than that.