qid int64 1 74.7M | question stringlengths 12 33.8k | date stringlengths 10 10 | metadata list | response_j stringlengths 0 115k | response_k stringlengths 2 98.3k |
|---|---|---|---|---|---|
10,239 | The first time that I brewed with whole flower / leaf hops, my more-experienced homebrewing friend said that I should have more wort than usual at the start of the boil, because the dried leaves will reconstitute and absorb liquid. I followed her directions, and I was pleased with the ultimate result. Naturally, I forgot her exact directions.
These are the [hops](http://www.oakbarrel.com/beermaking/hops_flower_chinook.shtml) that I'm using.
Is having extra wort a proper adjustment for these types of hops, and if so, how much extra wort should I have? | 2013/07/04 | [
"https://homebrew.stackexchange.com/questions/10239",
"https://homebrew.stackexchange.com",
"https://homebrew.stackexchange.com/users/3466/"
] | An experiment to determine wort absorption by whole leaf hope is described [here](http://www.homebrewtalk.com/f12/leaf-hop-absorption-measured-241469/). The conclusion was that an ounce of hops absorbs 0.15 quarts of wort. | Dried leaf hops absorb 4-6 times their own weight in wort. So, if you add 4oz/100g of hops in the boil, that's in the region of 16-24fl.oz/400-600ml of wort that you could lose. Naturally, the losses become more significant the more hops you add to the boil.
Most brewers intentionally overshoot slightly on the batch volume, e.g. target 5.5 or 6 gallons for a 5 gallon batch. If you're brewing a beer with 8oz/200g or more of hops, then use the numbers above to compute the additional volume needed to counter the losses. |
11,225 | I live in an old apartment with radiators for heat, The gas boiler is down two levels in the basement. oddly enough there are no cold air returns...is this correct? Our carbon monoxide alarm continuously goes off when the heat is turned up, we cook on our ELECTRIC STOVE. If we forget to turn the heat down at night, we all wake up with headaches and nausea. What is your guess as to what is wrong. | 2012/01/08 | [
"https://diy.stackexchange.com/questions/11225",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/4831/"
] | If your carbon monoxide detector is going off, you have a carbon monoxide problem. Contact your utility or local emergency services for a more thorough test. The symptoms you describe are consistent with early stages of carbon monoxide poisoning.
If your radiators heat with hot water or steam, or another system other than forced air, you will not have return ducts. That is normal. Carbon monoxide inside homes typically originates from a gas-burning appliance directly -- so in your case it would be gases coming up from a heater or boiler (probably in the basement). Alternatively, it could be that the exhaust duct / chimney is leaking into your apartment, rather than completely exhausting outdoors.
Get this looked at right away by professionals. BE VERY CAREFUL and do not venture downstairs; if the CO problem is bad in your apartment, it might be much worse in the immediate surroundings of the heater. Be safe! | As your CO detector is going off:
1. Get you and your family into the fresh air
2. Call 911
The fire department will come and check everything and figure out where it's coming from. They have an expensive carbon monoxide meter and they will check if there is a CO leak. If they find something they will call the gas company to shut off the gas until the problem is fixed by professional.
If your CO detector goes off, assuming you have the cheap one from Home Depot, that means that there is more than 30 ppm which is very bad. If you and other people in the apartment have headache and nausea that certainly sounds like you have CO poisoning. You can have serious brain damage even with low level chronically poisoning of CO. To be sure you can go to the hospital and take a blood analysis for CO.
If the fire department didn't find anything that not mean that it's safe. If the plumber said you that the problem is fixed that not mean that it's fixed.
If you can, buy another CO detector. And call 911 as much time that it's go off.
About your question, technically what can happen, a lot of think, impossible to said like this, but you have a serious CO problem and should not ignore it. |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | The first and foremost difference between the two is that a PhD is "awarded" after defending a thesis (plus additional duties depending on the department). On the other hand, a PostDoc is a temporary working position that is assigned by some institution, whose completion does not require any defence.
What people do or do not do, researchwise, in their PhD and PostDocs is very much dependent on the area and on the department (you may look at other answers that go more in details on this and that I do not want to overwrite, as I would just copy and paste them). | This is akin to asking what's the difference between research master's and PhD, or Assistant to associate professor.
A postdoc, is the *next level* after PhD (though not a necessary one). This is the main point.
Practically, it is different, in that it is less formal, with less specific requirements, and you are paid for it, as you are employed, not a student, as other answers here explained well. |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | I want to address this question by citing my current Master's advisor when I asked him the same question:
1. In the Bachelor's, you learn the basics of the area.
2. In the Master's, you learn what people are doing in the field and how to read scientific papers.
3. As a PhD, you learn how to develop your own research and start having new ideas on the field.
4. As a Post-Doc, you learn how to mentor other people's research while producing your own work without supervision.
5. When you reach Professorship you only have to look smart! | I have always understood a postdoc to be a "post doctoral" position, that is a paid post. The idea of a postdoc position is to do research roughly in the area of the PhD, with the person gaining experience that would possibly be of help in gaining a full time position. |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | The first and foremost difference between the two is that a PhD is "awarded" after defending a thesis (plus additional duties depending on the department). On the other hand, a PostDoc is a temporary working position that is assigned by some institution, whose completion does not require any defence.
What people do or do not do, researchwise, in their PhD and PostDocs is very much dependent on the area and on the department (you may look at other answers that go more in details on this and that I do not want to overwrite, as I would just copy and paste them). | A postdoc is expected to know what they are doing, and to be productive researchers with minimal supervision. PhD students are learning how to be researchers: by the end of the process, they should be on par with a postdoc, but it will take time to get there
Edit: This comment has been copied from Barbara Robson's answer [here](https://www.quora.com/What-are-the-main-differences-between-post-doctoral-research-and-Ph-D-research). |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | I want to address this question by citing my current Master's advisor when I asked him the same question:
1. In the Bachelor's, you learn the basics of the area.
2. In the Master's, you learn what people are doing in the field and how to read scientific papers.
3. As a PhD, you learn how to develop your own research and start having new ideas on the field.
4. As a Post-Doc, you learn how to mentor other people's research while producing your own work without supervision.
5. When you reach Professorship you only have to look smart! | The first and foremost difference between the two is that a PhD is "awarded" after defending a thesis (plus additional duties depending on the department). On the other hand, a PostDoc is a temporary working position that is assigned by some institution, whose completion does not require any defence.
What people do or do not do, researchwise, in their PhD and PostDocs is very much dependent on the area and on the department (you may look at other answers that go more in details on this and that I do not want to overwrite, as I would just copy and paste them). |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | I have always understood a postdoc to be a "post doctoral" position, that is a paid post. The idea of a postdoc position is to do research roughly in the area of the PhD, with the person gaining experience that would possibly be of help in gaining a full time position. | A postdoc is expected to know what they are doing, and to be productive researchers with minimal supervision. PhD students are learning how to be researchers: by the end of the process, they should be on par with a postdoc, but it will take time to get there
Edit: This comment has been copied from Barbara Robson's answer [here](https://www.quora.com/What-are-the-main-differences-between-post-doctoral-research-and-Ph-D-research). |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | In mathematics, a "postdoc" is a special kind of faculty job you get just after your Ph.D. It may have a fixed term (not tenure track). It may have reduced teaching, so that you can concentrate on your research. You may have a "mentor" assigned to advise you on doing research.
But (unlike some other fields like experimental physics) you are probably not working in someone else's "lab" on someone else's research program that someone else got the funding for. | A postdoc is expected to know what they are doing, and to be productive researchers with minimal supervision. PhD students are learning how to be researchers: by the end of the process, they should be on par with a postdoc, but it will take time to get there
Edit: This comment has been copied from Barbara Robson's answer [here](https://www.quora.com/What-are-the-main-differences-between-post-doctoral-research-and-Ph-D-research). |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | In mathematics, a "postdoc" is a special kind of faculty job you get just after your Ph.D. It may have a fixed term (not tenure track). It may have reduced teaching, so that you can concentrate on your research. You may have a "mentor" assigned to advise you on doing research.
But (unlike some other fields like experimental physics) you are probably not working in someone else's "lab" on someone else's research program that someone else got the funding for. | This is akin to asking what's the difference between research master's and PhD, or Assistant to associate professor.
A postdoc, is the *next level* after PhD (though not a necessary one). This is the main point.
Practically, it is different, in that it is less formal, with less specific requirements, and you are paid for it, as you are employed, not a student, as other answers here explained well. |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | I want to address this question by citing my current Master's advisor when I asked him the same question:
1. In the Bachelor's, you learn the basics of the area.
2. In the Master's, you learn what people are doing in the field and how to read scientific papers.
3. As a PhD, you learn how to develop your own research and start having new ideas on the field.
4. As a Post-Doc, you learn how to mentor other people's research while producing your own work without supervision.
5. When you reach Professorship you only have to look smart! | This is akin to asking what's the difference between research master's and PhD, or Assistant to associate professor.
A postdoc, is the *next level* after PhD (though not a necessary one). This is the main point.
Practically, it is different, in that it is less formal, with less specific requirements, and you are paid for it, as you are employed, not a student, as other answers here explained well. |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | In mathematics, a "postdoc" is a special kind of faculty job you get just after your Ph.D. It may have a fixed term (not tenure track). It may have reduced teaching, so that you can concentrate on your research. You may have a "mentor" assigned to advise you on doing research.
But (unlike some other fields like experimental physics) you are probably not working in someone else's "lab" on someone else's research program that someone else got the funding for. | I have always understood a postdoc to be a "post doctoral" position, that is a paid post. The idea of a postdoc position is to do research roughly in the area of the PhD, with the person gaining experience that would possibly be of help in gaining a full time position. |
104,865 | I am a PhD student in Mathematics. I wanted to know what exactly is the difference between PhD and Postdoc. Is it just the research that one does after PhD(kind of second PhD?)? | 2018/03/03 | [
"https://academia.stackexchange.com/questions/104865",
"https://academia.stackexchange.com",
"https://academia.stackexchange.com/users/88407/"
] | I want to address this question by citing my current Master's advisor when I asked him the same question:
1. In the Bachelor's, you learn the basics of the area.
2. In the Master's, you learn what people are doing in the field and how to read scientific papers.
3. As a PhD, you learn how to develop your own research and start having new ideas on the field.
4. As a Post-Doc, you learn how to mentor other people's research while producing your own work without supervision.
5. When you reach Professorship you only have to look smart! | A postdoc is expected to know what they are doing, and to be productive researchers with minimal supervision. PhD students are learning how to be researchers: by the end of the process, they should be on par with a postdoc, but it will take time to get there
Edit: This comment has been copied from Barbara Robson's answer [here](https://www.quora.com/What-are-the-main-differences-between-post-doctoral-research-and-Ph-D-research). |
5,758,785 | I'm looking for an IMAP client library or parser that can support asynchronous I/O. The end goal being I could have dedicated thread(s) do socket I/O (via a poll() loop or similar) and could send data to waiting clients/parsers, as it becomes available. All of the code/libraries I've seen to date (java.mail, Python's imaplib, Thunderbird's C++ IMAP client, many random ones in C, C++) seem to follow the traditional blocking, one-thread-per-socket approach, which won't work for me.
My ideal client or library would behave much like <https://github.com/ry/http-parser> in that I/O behavior would not be dictated by the IMAP bits. Instead, the IMAP library would deal with buffers/strings and the caller would manage I/O.
The only possibility I've seen so far is libcurl. But, I'm not sure if the API will work and want to look at other possibilities before going too far down that road or inventing my own solution.
I'm open to considering libraries in any programming language. | 2011/04/22 | [
"https://Stackoverflow.com/questions/5758785",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/502665/"
] | Twisted (<http://twistedmatrix.com/>) has an asynchronous IMAP4 client: twisted.mail.imap4.IMAP4Client
People sometimes say that this protocol is difficult to implement, so implementation quality may be an issue. The defunct Chandler project used the twisted IMAP4 client, and its source code contains the comment "This functionality will be enhanced to be a more robust IMAP client in the near future". | I've had great results with node.js for this kind of thing. If listening to a lot of open sockets you'll need to tweak some linux settings to increase limits for the number of open file discriptors but it works great. |
79,032 | Does someone have some reliable source what was meant by quote by Søren Kierkegaard in the title? Can you elaborate?
Does it mean for example I shouldn't think how to solve some problem, rather say go out and experience a nice walk for example? | 2021/02/11 | [
"https://philosophy.stackexchange.com/questions/79032",
"https://philosophy.stackexchange.com",
"https://philosophy.stackexchange.com/users/50303/"
] | I don't think that's what the author meant by the quote at all. He's not dissuading us from thinking logically or analytically, but attempting to shift our focus from that of problem-solving to *enjoying life*.
As humans, we are natural thinkers and problem solvers. Our brains are wired to seek truth and to find solutions to questions and issues that arise throughout our time here on this earth.
The trap many philosophers seem to find themselves in is one of constant pondering. Sure, everything can and should be open to intellectual debate, but is this the true purpose of our experience?
Instead of thinking about *why* the grass feels the way it does on our bare feet, we should simply quiet our minds and enjoy the fleeting moment for what it is.
Life. | Of course you should regard solving problems as your serious main business, while enjoying life as a vacation period after long persistent effort drowning in your business. As Farady once famously said: the strong prove, the weak enjoy... Also anyway, aren't problems must also be reality to be experienced? Otherwise it's just a fake manufactured "problem".
Don't read too much words into you heart, different people have different or even opposite styles and ways to express similar innate ideas. The real issue I observed from my experience is people will easily attach too much importance, value, and ego into their main business, their domain of problems, to such an extreme that they begin to overlook, disregard, and even say bad words to other people's totally different businesses. So under this context, a saint saying your above words are totally fine and appropriate. But we all know a saint's major job is to solve other people's sufferings (problems)... |
24,382 | I recently noticed that what I think are the inner CV boots on my 99 Nissan Almera have started coming apart:
[](https://i.stack.imgur.com/imSrE.jpg)
They were still in one piece this past August when I took the car for inspection, so this is fairly recent.
How urgent is it to deal with this and what are the possible negative consequences of waiting an extended period of time, say six months, before dealing with it. I ask that because I'm anyways planning on replacing the struts before the next inspection as they've been leaking for a few months and I'm starting to feel the car is more jiggly when going over bumps. | 2016/01/08 | [
"https://mechanics.stackexchange.com/questions/24382",
"https://mechanics.stackexchange.com",
"https://mechanics.stackexchange.com/users/7132/"
] | From my experience of CV boots, you need to replace them immediately if you want to keep the CV joint it covers. It doesn't take long for dirt to destroy the joint once it gets inside the boot. If you leave it until the joint starts to deteriorate, then you risk failure of the joint at probably at dangerous time when the car is turning around a corner. | you should take care that lubricating grease will go out which will cause CV damage by time. |
24,382 | I recently noticed that what I think are the inner CV boots on my 99 Nissan Almera have started coming apart:
[](https://i.stack.imgur.com/imSrE.jpg)
They were still in one piece this past August when I took the car for inspection, so this is fairly recent.
How urgent is it to deal with this and what are the possible negative consequences of waiting an extended period of time, say six months, before dealing with it. I ask that because I'm anyways planning on replacing the struts before the next inspection as they've been leaking for a few months and I'm starting to feel the car is more jiggly when going over bumps. | 2016/01/08 | [
"https://mechanics.stackexchange.com/questions/24382",
"https://mechanics.stackexchange.com",
"https://mechanics.stackexchange.com/users/7132/"
] | From my experience of CV boots, you need to replace them immediately if you want to keep the CV joint it covers. It doesn't take long for dirt to destroy the joint once it gets inside the boot. If you leave it until the joint starts to deteriorate, then you risk failure of the joint at probably at dangerous time when the car is turning around a corner. | IMMEDIATELY, If it is not too late already, I have seen CVs ruined with days not weeks, by the smallest amount of sand, mud, dirt whatever getting into the joint.
These are way too expensive to take the chance.
I am not familiar with your model, but trying to save on labour cost doesn't usually equate to the cost of new cvs, (depending on costs in your situation). |
24,382 | I recently noticed that what I think are the inner CV boots on my 99 Nissan Almera have started coming apart:
[](https://i.stack.imgur.com/imSrE.jpg)
They were still in one piece this past August when I took the car for inspection, so this is fairly recent.
How urgent is it to deal with this and what are the possible negative consequences of waiting an extended period of time, say six months, before dealing with it. I ask that because I'm anyways planning on replacing the struts before the next inspection as they've been leaking for a few months and I'm starting to feel the car is more jiggly when going over bumps. | 2016/01/08 | [
"https://mechanics.stackexchange.com/questions/24382",
"https://mechanics.stackexchange.com",
"https://mechanics.stackexchange.com/users/7132/"
] | IMMEDIATELY, If it is not too late already, I have seen CVs ruined with days not weeks, by the smallest amount of sand, mud, dirt whatever getting into the joint.
These are way too expensive to take the chance.
I am not familiar with your model, but trying to save on labour cost doesn't usually equate to the cost of new cvs, (depending on costs in your situation). | you should take care that lubricating grease will go out which will cause CV damage by time. |
2,530 | What is the advantage for rockets to [have multiple stages](http://en.wikipedia.org/wiki/Multistage_rocket)?
Wouldn't a single stage with the same amount of fuel weigh less?
**Note** I would like a quantitative answer, if possible :-)
 | 2011/01/05 | [
"https://physics.stackexchange.com/questions/2530",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/66/"
] | As Omega Centauri wrote, it is mainly about removing unused tank mass; for numbers, see Wikipedia article about [Ciołkowski's equation](http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation), especially the [example](http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation#Examples) there. | Launch weight would be lower if you had a fixed fuel load, and only one engine and fuel tank. However the specific impulse applied to the payload would be lower. The problem is that even when the fuel is say 90% exhausted, the rocket is still trying to accelerate the now grossly oversized fuel tank and engine. So the trick is to try to reduce the deadweight (structural mass) as the fuel is consumed. Another compromise system is to have jetisonable external fuel tanks, like the shuttle, which are thrown away once their fuel is consumed. |
2,530 | What is the advantage for rockets to [have multiple stages](http://en.wikipedia.org/wiki/Multistage_rocket)?
Wouldn't a single stage with the same amount of fuel weigh less?
**Note** I would like a quantitative answer, if possible :-)
 | 2011/01/05 | [
"https://physics.stackexchange.com/questions/2530",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/66/"
] | Launch weight would be lower if you had a fixed fuel load, and only one engine and fuel tank. However the specific impulse applied to the payload would be lower. The problem is that even when the fuel is say 90% exhausted, the rocket is still trying to accelerate the now grossly oversized fuel tank and engine. So the trick is to try to reduce the deadweight (structural mass) as the fuel is consumed. Another compromise system is to have jetisonable external fuel tanks, like the shuttle, which are thrown away once their fuel is consumed. | The easiest way to think of it is this, imagine all the mass left over when a rocket has burned 85% of it's fuel. The mass of most of the tank and structure is now overkill and waste. It would be nice to be able to jettison that extra mass so that the fuel left can accelerate only the payload.
That's what a multi-stage rocket does. It jettisons the mass of initial stages so that the remaining fuel and thrust can accelerate much smaller mass to a much higher velocity than it would have been able to if there was only one stage. Remember acceleration is proportional to mass, so if you can get rid of say 80% of the mass then you can accelerate the payload 5 times more for the same remaining fuel.
Another benefit is that you can use rocket motors that are tuned for different velocities. In the initial stage you need maximum thrust and the rocket is not moving as fast. In the later stages you want high efficiency motors, not necessarily high thrust.
To get very high velocities it requires less overall fuel and mass with multiple stages. This comes at the cost of greater complexity and cost. |
2,530 | What is the advantage for rockets to [have multiple stages](http://en.wikipedia.org/wiki/Multistage_rocket)?
Wouldn't a single stage with the same amount of fuel weigh less?
**Note** I would like a quantitative answer, if possible :-)
 | 2011/01/05 | [
"https://physics.stackexchange.com/questions/2530",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/66/"
] | Launch weight would be lower if you had a fixed fuel load, and only one engine and fuel tank. However the specific impulse applied to the payload would be lower. The problem is that even when the fuel is say 90% exhausted, the rocket is still trying to accelerate the now grossly oversized fuel tank and engine. So the trick is to try to reduce the deadweight (structural mass) as the fuel is consumed. Another compromise system is to have jetisonable external fuel tanks, like the shuttle, which are thrown away once their fuel is consumed. | Another aspect to consider is the burn characteristics of the rocket motors. This is especially important in solid rocket motors because once lit, they are self-oxidizing and are not easy to turn off.
At low altitudes, the rocket should not accelerate too rapidly because the air is very dense and the power required is proportional to velocity cubed. So you just want to get the thing going until you reach an altitude where the air is less dense and it's more economical to go fast. So you may have a first stage that burns relatively slowly.
Once that burns and you reach a higher altitude where you can go faster, you drop your "slow burn" motor and kick on your powerful motor. Now the air density is much lower so you can accelerate as quickly as you want and reach whatever speed is needed.
A third stage might be used to fine-tune the speed and position the craft in whatever orbit or trajectory is needed.
Furthermore, because the air pressure decreases with altitude, the ideal nozzle shape is not the same at low altitude as high. An [overexpanded nozzle](http://en.wikipedia.org/wiki/Rocket_engine_nozzle#Aerostatic_back-pressure_and_optimum_expansion) at sea-level can be an underexpanded nozzle at altitude resulting in a very narrow range where it is operating at maximum efficiency.
You could design adaptive nozzles but they are very heavy and expensive, and they can't really be made to service the full range. Or, you could have stages with fixed nozzles that are designed to be as efficient as possible over the range of altitudes serviced.
So, in addition to the answers above about dropping weight as you go resulting in less fuel use, each stage can also be designed to take into account the operating regime and needs by carefully selecting the fuel for appropriate thrust/burn rates and by designing the nozzle for the nominal operating conditions for the altitudes serviced by the motor. Both of which lead to a much more efficient motor and thus less fuel. |
2,530 | What is the advantage for rockets to [have multiple stages](http://en.wikipedia.org/wiki/Multistage_rocket)?
Wouldn't a single stage with the same amount of fuel weigh less?
**Note** I would like a quantitative answer, if possible :-)
 | 2011/01/05 | [
"https://physics.stackexchange.com/questions/2530",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/66/"
] | As Omega Centauri wrote, it is mainly about removing unused tank mass; for numbers, see Wikipedia article about [Ciołkowski's equation](http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation), especially the [example](http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation#Examples) there. | The easiest way to think of it is this, imagine all the mass left over when a rocket has burned 85% of it's fuel. The mass of most of the tank and structure is now overkill and waste. It would be nice to be able to jettison that extra mass so that the fuel left can accelerate only the payload.
That's what a multi-stage rocket does. It jettisons the mass of initial stages so that the remaining fuel and thrust can accelerate much smaller mass to a much higher velocity than it would have been able to if there was only one stage. Remember acceleration is proportional to mass, so if you can get rid of say 80% of the mass then you can accelerate the payload 5 times more for the same remaining fuel.
Another benefit is that you can use rocket motors that are tuned for different velocities. In the initial stage you need maximum thrust and the rocket is not moving as fast. In the later stages you want high efficiency motors, not necessarily high thrust.
To get very high velocities it requires less overall fuel and mass with multiple stages. This comes at the cost of greater complexity and cost. |
2,530 | What is the advantage for rockets to [have multiple stages](http://en.wikipedia.org/wiki/Multistage_rocket)?
Wouldn't a single stage with the same amount of fuel weigh less?
**Note** I would like a quantitative answer, if possible :-)
 | 2011/01/05 | [
"https://physics.stackexchange.com/questions/2530",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/66/"
] | As Omega Centauri wrote, it is mainly about removing unused tank mass; for numbers, see Wikipedia article about [Ciołkowski's equation](http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation), especially the [example](http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation#Examples) there. | Another aspect to consider is the burn characteristics of the rocket motors. This is especially important in solid rocket motors because once lit, they are self-oxidizing and are not easy to turn off.
At low altitudes, the rocket should not accelerate too rapidly because the air is very dense and the power required is proportional to velocity cubed. So you just want to get the thing going until you reach an altitude where the air is less dense and it's more economical to go fast. So you may have a first stage that burns relatively slowly.
Once that burns and you reach a higher altitude where you can go faster, you drop your "slow burn" motor and kick on your powerful motor. Now the air density is much lower so you can accelerate as quickly as you want and reach whatever speed is needed.
A third stage might be used to fine-tune the speed and position the craft in whatever orbit or trajectory is needed.
Furthermore, because the air pressure decreases with altitude, the ideal nozzle shape is not the same at low altitude as high. An [overexpanded nozzle](http://en.wikipedia.org/wiki/Rocket_engine_nozzle#Aerostatic_back-pressure_and_optimum_expansion) at sea-level can be an underexpanded nozzle at altitude resulting in a very narrow range where it is operating at maximum efficiency.
You could design adaptive nozzles but they are very heavy and expensive, and they can't really be made to service the full range. Or, you could have stages with fixed nozzles that are designed to be as efficient as possible over the range of altitudes serviced.
So, in addition to the answers above about dropping weight as you go resulting in less fuel use, each stage can also be designed to take into account the operating regime and needs by carefully selecting the fuel for appropriate thrust/burn rates and by designing the nozzle for the nominal operating conditions for the altitudes serviced by the motor. Both of which lead to a much more efficient motor and thus less fuel. |
44,897 | How does the stack work for this scenario?
[Hushwing Gryff](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bHushwing%20Gryff%5d) is already in play and the player goes to cast [Eater of Days](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bEater%20of%20Days%5d) so the Hushwing Gryff will cancel out the loss of two turns. In response the opponent either casts [Lightning Bolt](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bLightning%20Bolt%5d) or [Path to Exile](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bPath%20to%20Exile%5d) on the Hushwing Gryff while Eater of Days is still on the stack.
Does either the Bolt or Path remove the Hushwing Gryff, so when the Eater of Days resolves the player loses two turns? | 2019/01/25 | [
"https://boardgames.stackexchange.com/questions/44897",
"https://boardgames.stackexchange.com",
"https://boardgames.stackexchange.com/users/26222/"
] | The opponent can use either spell to target [Hushwing Gryff](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bHushwing%20Gryff%5d) while Eater of Days is on the stack. In this case,
* The spell resolves first, removing Hushwing Gryff from the battlefield.
* Eater of Days resolves, and as there is no Hushwing Gryff on the battlefield the caster of Eater of Days loses two turns. | Yes, that's how it works. Basically, what is cast *last* will resolve *first*. Once the Eater of Days enters the battlefield, Hushwing Gryff is already gone and the enter-the-battlefield trigger will function as normal. |
16,641,655 | I made some changes to a CSS file, uploaded it and saw no change. I cleared my browser's cache, repeated the process and still nothing. I also tried another browser and then experimented with other files - all the same result.I then deleted the CSS file altogether - the website still looks the same and I can still see the files in the browser's console.
I can only get results if I actually change the file names altogether (which is really inconvenient). I dont think there is an issue with FTP overwriting the file as there are no errors in FileZillas logs.
Is there another way a website can cache its self? Would anyone know why this is occurring?
EDIT:
I also tried this in cPanel's File Manager and viewed it on another PC - same result | 2013/05/20 | [
"https://Stackoverflow.com/questions/16641655",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1433268/"
] | [Squid](http://en.wikipedia.org/wiki/Squid_%28software%29) and other web accelerators often sit between a hosted server and your browser. Although they are supposed to invalidate their caches when the backing file changes, that information isn't always sent to specification or acted on properly.
Indeed, there can be multiple caches between you and the server each of which has a chance of hanging onto old data. | **First**, use Firebug or "Inspect Element" in chrome.
Verify that the css file that the browser is loading the file you think is should load.
Good luck. |
16,641,655 | I made some changes to a CSS file, uploaded it and saw no change. I cleared my browser's cache, repeated the process and still nothing. I also tried another browser and then experimented with other files - all the same result.I then deleted the CSS file altogether - the website still looks the same and I can still see the files in the browser's console.
I can only get results if I actually change the file names altogether (which is really inconvenient). I dont think there is an issue with FTP overwriting the file as there are no errors in FileZillas logs.
Is there another way a website can cache its self? Would anyone know why this is occurring?
EDIT:
I also tried this in cPanel's File Manager and viewed it on another PC - same result | 2013/05/20 | [
"https://Stackoverflow.com/questions/16641655",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1433268/"
] | [Squid](http://en.wikipedia.org/wiki/Squid_%28software%29) and other web accelerators often sit between a hosted server and your browser. Although they are supposed to invalidate their caches when the backing file changes, that information isn't always sent to specification or acted on properly.
Indeed, there can be multiple caches between you and the server each of which has a chance of hanging onto old data. | Browsers can cache things, did you try SHIFT-F5 on your webpage to force a reload of everything? |
16,641,655 | I made some changes to a CSS file, uploaded it and saw no change. I cleared my browser's cache, repeated the process and still nothing. I also tried another browser and then experimented with other files - all the same result.I then deleted the CSS file altogether - the website still looks the same and I can still see the files in the browser's console.
I can only get results if I actually change the file names altogether (which is really inconvenient). I dont think there is an issue with FTP overwriting the file as there are no errors in FileZillas logs.
Is there another way a website can cache its self? Would anyone know why this is occurring?
EDIT:
I also tried this in cPanel's File Manager and viewed it on another PC - same result | 2013/05/20 | [
"https://Stackoverflow.com/questions/16641655",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1433268/"
] | [Squid](http://en.wikipedia.org/wiki/Squid_%28software%29) and other web accelerators often sit between a hosted server and your browser. Although they are supposed to invalidate their caches when the backing file changes, that information isn't always sent to specification or acted on properly.
Indeed, there can be multiple caches between you and the server each of which has a chance of hanging onto old data. | Maybe the main server has cached configuration setup to other servers, check with your IT department. If this is the case, you need to tell them to invalidate the cache through all the cached servers. |
16,641,655 | I made some changes to a CSS file, uploaded it and saw no change. I cleared my browser's cache, repeated the process and still nothing. I also tried another browser and then experimented with other files - all the same result.I then deleted the CSS file altogether - the website still looks the same and I can still see the files in the browser's console.
I can only get results if I actually change the file names altogether (which is really inconvenient). I dont think there is an issue with FTP overwriting the file as there are no errors in FileZillas logs.
Is there another way a website can cache its self? Would anyone know why this is occurring?
EDIT:
I also tried this in cPanel's File Manager and viewed it on another PC - same result | 2013/05/20 | [
"https://Stackoverflow.com/questions/16641655",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1433268/"
] | [Squid](http://en.wikipedia.org/wiki/Squid_%28software%29) and other web accelerators often sit between a hosted server and your browser. Although they are supposed to invalidate their caches when the backing file changes, that information isn't always sent to specification or acted on properly.
Indeed, there can be multiple caches between you and the server each of which has a chance of hanging onto old data. | I had the same issue with fileZilla to solve it you need to clear the file zilla cache or change the name of the files you are uploading.
Open FileZilla and click on the Edit menu.
Choose Clear Private Data.
In the new dialog box, check mark the categories you’d like to clear: Quickconnect history, Reconnect information, Site Manager entries, Transfer queue.
Finally, click OK to validate |
7,799,119 | I need to live-demo a Mobile Safari browser app (iOS 5, iPhone 4S) on my Macbook and was wondering the best way to do this?
One way I thought might be possible would be using AirPlay Mirroring, but there doesn't seem to be any Mac OS apps capable of showing my iPhone screen mirrored.
I am an (beginner) iOS developer and wondered if there was anyway I could knock up a basic app with a UIWebView in it to somehow stream the contents of the web page and my interactions with it to my Mac.
Any thoughts?
*EDIT*: Yes I know I could use the iPhone Simulator, but I need to interact with it on the handset using the mobile phone network. | 2011/10/17 | [
"https://Stackoverflow.com/questions/7799119",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/312817/"
] | Since your device (iPhone 4s) supports video mirroring via AirPlay, then you should be able to use [AirServer](http://www.airserverapp.com/) to enable mirroring to your Mac.
Update: As pointed out by Marc Surman, AirServer does not support mirroring, rendering this answer incorrect. Thanks for playing. | Mirroring uses FairPlay encryption, which is why AirServer and similar applications can't do mirroring.
You CAN, however, fake this using AirplayKit:
<https://github.com/rothacr/AirplayKit>
The iOS demo in that repo actually does a simple mirror by sending an image of your screen to the airplay device using a timer. It would probably work just fine for a demo, and should work with AirServer. |
7,799,119 | I need to live-demo a Mobile Safari browser app (iOS 5, iPhone 4S) on my Macbook and was wondering the best way to do this?
One way I thought might be possible would be using AirPlay Mirroring, but there doesn't seem to be any Mac OS apps capable of showing my iPhone screen mirrored.
I am an (beginner) iOS developer and wondered if there was anyway I could knock up a basic app with a UIWebView in it to somehow stream the contents of the web page and my interactions with it to my Mac.
Any thoughts?
*EDIT*: Yes I know I could use the iPhone Simulator, but I need to interact with it on the handset using the mobile phone network. | 2011/10/17 | [
"https://Stackoverflow.com/questions/7799119",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/312817/"
] | The situation has changed since this was asked.
AirServer (AirServerApp.com) and Reflection (ReflectionApp.com) both support AirPlay mirroring. Here's an article comparing them:
<http://www.macstories.net/reviews/mirroring-multiple-ios-devices-to-a-mac-comparing-airserver-and-reflection/> | Since your device (iPhone 4s) supports video mirroring via AirPlay, then you should be able to use [AirServer](http://www.airserverapp.com/) to enable mirroring to your Mac.
Update: As pointed out by Marc Surman, AirServer does not support mirroring, rendering this answer incorrect. Thanks for playing. |
7,799,119 | I need to live-demo a Mobile Safari browser app (iOS 5, iPhone 4S) on my Macbook and was wondering the best way to do this?
One way I thought might be possible would be using AirPlay Mirroring, but there doesn't seem to be any Mac OS apps capable of showing my iPhone screen mirrored.
I am an (beginner) iOS developer and wondered if there was anyway I could knock up a basic app with a UIWebView in it to somehow stream the contents of the web page and my interactions with it to my Mac.
Any thoughts?
*EDIT*: Yes I know I could use the iPhone Simulator, but I need to interact with it on the handset using the mobile phone network. | 2011/10/17 | [
"https://Stackoverflow.com/questions/7799119",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/312817/"
] | The situation has changed since this was asked.
AirServer (AirServerApp.com) and Reflection (ReflectionApp.com) both support AirPlay mirroring. Here's an article comparing them:
<http://www.macstories.net/reviews/mirroring-multiple-ios-devices-to-a-mac-comparing-airserver-and-reflection/> | Mirroring uses FairPlay encryption, which is why AirServer and similar applications can't do mirroring.
You CAN, however, fake this using AirplayKit:
<https://github.com/rothacr/AirplayKit>
The iOS demo in that repo actually does a simple mirror by sending an image of your screen to the airplay device using a timer. It would probably work just fine for a demo, and should work with AirServer. |
19,537,413 | Wikipedia says Miller columns "resemble" something used earlier in Smalltalk and was independently invented by Miller. Who was first - Smalltalk or Miller?
If Smalltalk was first, then who exactly invented Miller columns and why Miller columns are Miller Columns, not X columns, where X is last name of the inventor?
If Miller was first, why Smalltalk is mentioned? | 2013/10/23 | [
"https://Stackoverflow.com/questions/19537413",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645317/"
] | The Smalltalk mechanism being referenced was the class hierarchy browser. It was invented in 1976 by Larry Tesler (see Alan Kay "The Early History of Smalltalk" under "Smalltalk-76"). The browser used a fixed 4-list view to locate source code for methods. The first list was for categories. Within each category you could select a class in the second list. Once a class was selected, a method protocol could be selected from the third list. Finally, once a method protocol was selected, a method could be selected from the fourth list. Upon selecting a method, the source code for the method appeared in the text editor below the 4 lists. This is an example of a special-purpose fixed-depth miller column.
From my reading of the wikipedia article, it seems that Miller columns were more general and had an arbitrary number of columns. It's believable that Miller had no knowledge of the Smalltalk browser - the browser wasn't made generally available until the public release of Smalltalk-80 in 1983. Before then, it was only used by people associated with Xerox and by a handful of companies that were asked to port Smalltalk-80 to their own hardware. (See Smalltalk - Bits of History and Words of Advice). Screenshots of a class hierarchy browser did appear in the 1981 issue of Byte magazine (page 124 onward) but again, this was after the 1980 invention of Miller columns.
It makes sense, then, that the more general mechanism was named after Miller with people afterwards noticing similarities to the Smalltalk browser. | Miller Columns are closely related to techniques used earlier in the Smalltalk browser, they were invented by Mark S. Miller, though at Yale University in 1980. Refer to the following url
for more information
[Miller Columns](http://appuntitech.blogspot.in/2013/01/miller-columns.html) |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The pro of a fire steel over other lighters is that there's little that can break or be damaged from weather. Even if you lose the striker, a steel knife will work with the flint. However the con is that you only get a spark, not a steady flame. That means it needs to hit something that will ignite very easily. I use it to light my stoves (alcohol and isobutane) but I wouldn't want to try to start a fire with that and twigs. If you need to step it up to the next level, they make magnesium starters which you shave off some of the magnesium and hit that with a spark to light whatever the magnesium is in contact with.
I've only used a cheap "made in china" type, so I have no idea if others might be better. But we're only talking about a piece of metal so I'm not sure there's a big difference in quality. I'd suggest looking at quantity over quality, and get the largest size for the money. The sparks are from the flint being worn off, so a smaller flint will be worn away quicker.
To use, I prefer a handle on the flint to give me a better grip. You place the steel close to 90° against the flint, and point the flint towards the object you want to light. You can push the steel down the flint, but I like to pull the flint back away from the target since it gives me more control and there's less risk of blowing out what I'm trying to light. This is a fast scrape motion, not a strike. Maintain the right angle and pressure and sparks will fly easily.
I haven't tried the fire drill or piston, but keep in mind that you don't have highly accurate aim with the fire steel. This means it's much more trial and error to get the spark to hit just the right spot on your target.
The thing I like the best with fire steels is their reliability and durability. But because they don't provide a constant flame, I tend to keep matches as a backup. | For most uses, a Storm Lighter is going to be more practical, but if something were to happen to the lighter (runs out of fuel, crack in the reservoir, etc) it would be very nice to have something that is going to work.
The biggest benefit to using the fire stick is the simplicity. You'll have to have something that will catch a spark, but once you have that there is almost no learning curve to producing sparks with the fire stick. I've used mine many times to light small bundles of dryer lint to start fires and it only takes a few strikes before I have a small fire going. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The big plus with a firesteel is that you can pretty much do what you want to it, including soaking the thing in ice cold water, and it'll still work as well as before. The big downside is it's just sparks, so it's harder to build a fire.
However, with practice, it's not that hard and does provide a good backup if your matches get soaked through and your lighter gets damaged.
In terms of specific questions:
* I have two or three brands and I see no discernible difference between them.
* The bigger the better - the thicker it is, the longer it will last before being worn down.
* Any flat blade will generally do the trick, though if you use a sharp knife bear in mind it'll get worn down quite quickly.
* I prefer rods on handles - it makes it a lot easier to hold whilst using.
* You scrape rather than strike, still relatively fast. However, I've found good pressure and angle is much more important than speed. When practicing, go slowly - you'll improve your technique and be surprised how many sparks you can create this way.
* No real specific precautions you need to bear in mind, just the general ones when you're dealing with fire! | For most uses, a Storm Lighter is going to be more practical, but if something were to happen to the lighter (runs out of fuel, crack in the reservoir, etc) it would be very nice to have something that is going to work.
The biggest benefit to using the fire stick is the simplicity. You'll have to have something that will catch a spark, but once you have that there is almost no learning curve to producing sparks with the fire stick. I've used mine many times to light small bundles of dryer lint to start fires and it only takes a few strikes before I have a small fire going. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The big plus with a firesteel is that you can pretty much do what you want to it, including soaking the thing in ice cold water, and it'll still work as well as before. The big downside is it's just sparks, so it's harder to build a fire.
However, with practice, it's not that hard and does provide a good backup if your matches get soaked through and your lighter gets damaged.
In terms of specific questions:
* I have two or three brands and I see no discernible difference between them.
* The bigger the better - the thicker it is, the longer it will last before being worn down.
* Any flat blade will generally do the trick, though if you use a sharp knife bear in mind it'll get worn down quite quickly.
* I prefer rods on handles - it makes it a lot easier to hold whilst using.
* You scrape rather than strike, still relatively fast. However, I've found good pressure and angle is much more important than speed. When practicing, go slowly - you'll improve your technique and be surprised how many sparks you can create this way.
* No real specific precautions you need to bear in mind, just the general ones when you're dealing with fire! | **Why would one want one of these rather than a Storm Lighter?**
The advantage of a ferro rod is that it is simple, reliable and lasts a long time. There are no moving parts to break or fuel to run out. They will gradually wear down but they last a very long time for their weight and you can see how much material is left. Even if one breaks the broken parts should still be usable.
**Is one type or brand more effective than another?**
I've used various brands and generic ones, they all seem pretty much the same to me.
**Sizes are all over the map. Do these all work equally well? Is it just a matter of lifespan?**
Pretty much, a larger one will last longer and is perhaps marginally easier to use but there isn't a lot in it. I find the larger sizes (around 100mm x 10mm diameter) easiest to use.
**There are bare rods, rods on lanyards, and rods in handles. How does it matter?**
A lanyard is useful to stop it getting lost as you can attach it to your equipment. Some people keep them in a loop on their knife sheath so handle and/or lanyard makes them easier to get in and out. With a bare rod you can also make a handle of the size, shape and material you prefer. Some knife makers make ferro rod handles to match a particular knife.
A plain rod though is easier to pack in a survival kit and the smaller ones take up less space than most lighters.
**What is needed to make sparks with one of these rods? Will natural flint work as a striker?**
You need something reasonably hard with a well defined edge, the spine of a knife is often used or a short length of hacksaw blade. Abrasive materials like sandpaper or rough rocks work too as will a sharp flake of flint. Files work extremely well. They are also soft enough that you can use the edge of a knife as striker with little risk of damaging it.
**Do you "strike" or "scrape" a fire steel? How do you hold it?**
Usually the best technique is to rest the end of the rod on your tinder and scrape downwards. If you are using an abrasive strike it may be easier to strike it like a match. But it's really a case of what is easiest for you. It take a *bit* of practice to get the best results but it is much easier than a flint and steel or friction methods.
As mentioned in the comment below the main aspect of proper technique is to strike/scrape it with enough force to produce good sparks without disturbing your tinder. My preferred method is to place a wad of tinder on a flat surface then trap it with the end of the rod and scrape down onto the tinder rather than holding it above the tinder and trying to aim the sparks.
In general you want to apply moderate pressure with the striker and use a fairly slow scraping movement.
**Can you use less sensitive tinder than is needed for a fire drill or fire piston?**
They generate quite a lot of reasonably hot sparks so they tend to light tinder more quickly and easily than friction methods or natural flint and steel and you can light most things which could be reasonably called 'tinder'. They can also light flammable liquids. With care you can also scrape off small shavings of the rod without igniting them which can help ignition.
They will usually light cotton wool at the first attempt and more difficult tinder like sawdust and paper are certainly achievable.
**Are there any special precautions or specific failures for fire steels?**
Not really, they don't like being soaked in water for long periods of time, but this is more an issue of long term storage than use. Obviously if you use a knife to strike them then basic cutting tool safety applies. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | I strike my fire steel with a piece of hacksaw blade. I have the added ability to either just strike/scrape the ferro rod, shave shavings off it into a tinder bundle to get more intense fire lighting sparks. I can use the striker to shave fat wood, or normal wood, which will in turn take less of a spark to ignite. I can attach a piece of paracord through the blades fixing hole so I can attach it to either the ferro rod, or keyring of some kind, or just to place as lanyard around the wrist for extra security so you don't use the striker when using. Also the teeth of the blade bite into the rod really well and will give you a lot of sparks with less effort, even when using cheaper harder material ferro rods that don't throw many sparks normally. | We use both. It is not difficult to light a fire with a ferrocerium rod especially if you have pine trees around as we do. A bit of sap from one of them on your shavings, cotton balls, spanish moss and one strike from the rod will start the fire. No sap? Then we also carry a small jar of vaseline. Both are overkill but help when you must light a fire in the pouring rain or high humidity. Small shavings can be made on site and charcloth is also usable with a firestick.
Two is one and one is none...Equipment fails under special conditions and that is why we do not skimp on firestarting ways. We have started fires using a magnifying lens which we needed when the guy carrying the firemaking tools decided to fall into the lake and drench our equipment. Only the firesteel and the magnifying glass worked then.
They are also a lot of fun but recommend watching a video or two to see the proper hand motions. Keep the stick when striking (scraping is the correct word), right on top or in the target. All of which you have probably done by now. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | I strike my fire steel with a piece of hacksaw blade. I have the added ability to either just strike/scrape the ferro rod, shave shavings off it into a tinder bundle to get more intense fire lighting sparks. I can use the striker to shave fat wood, or normal wood, which will in turn take less of a spark to ignite. I can attach a piece of paracord through the blades fixing hole so I can attach it to either the ferro rod, or keyring of some kind, or just to place as lanyard around the wrist for extra security so you don't use the striker when using. Also the teeth of the blade bite into the rod really well and will give you a lot of sparks with less effort, even when using cheaper harder material ferro rods that don't throw many sparks normally. | **Why would one want one of these rather than a Storm Lighter?**
The advantage of a ferro rod is that it is simple, reliable and lasts a long time. There are no moving parts to break or fuel to run out. They will gradually wear down but they last a very long time for their weight and you can see how much material is left. Even if one breaks the broken parts should still be usable.
**Is one type or brand more effective than another?**
I've used various brands and generic ones, they all seem pretty much the same to me.
**Sizes are all over the map. Do these all work equally well? Is it just a matter of lifespan?**
Pretty much, a larger one will last longer and is perhaps marginally easier to use but there isn't a lot in it. I find the larger sizes (around 100mm x 10mm diameter) easiest to use.
**There are bare rods, rods on lanyards, and rods in handles. How does it matter?**
A lanyard is useful to stop it getting lost as you can attach it to your equipment. Some people keep them in a loop on their knife sheath so handle and/or lanyard makes them easier to get in and out. With a bare rod you can also make a handle of the size, shape and material you prefer. Some knife makers make ferro rod handles to match a particular knife.
A plain rod though is easier to pack in a survival kit and the smaller ones take up less space than most lighters.
**What is needed to make sparks with one of these rods? Will natural flint work as a striker?**
You need something reasonably hard with a well defined edge, the spine of a knife is often used or a short length of hacksaw blade. Abrasive materials like sandpaper or rough rocks work too as will a sharp flake of flint. Files work extremely well. They are also soft enough that you can use the edge of a knife as striker with little risk of damaging it.
**Do you "strike" or "scrape" a fire steel? How do you hold it?**
Usually the best technique is to rest the end of the rod on your tinder and scrape downwards. If you are using an abrasive strike it may be easier to strike it like a match. But it's really a case of what is easiest for you. It take a *bit* of practice to get the best results but it is much easier than a flint and steel or friction methods.
As mentioned in the comment below the main aspect of proper technique is to strike/scrape it with enough force to produce good sparks without disturbing your tinder. My preferred method is to place a wad of tinder on a flat surface then trap it with the end of the rod and scrape down onto the tinder rather than holding it above the tinder and trying to aim the sparks.
In general you want to apply moderate pressure with the striker and use a fairly slow scraping movement.
**Can you use less sensitive tinder than is needed for a fire drill or fire piston?**
They generate quite a lot of reasonably hot sparks so they tend to light tinder more quickly and easily than friction methods or natural flint and steel and you can light most things which could be reasonably called 'tinder'. They can also light flammable liquids. With care you can also scrape off small shavings of the rod without igniting them which can help ignition.
They will usually light cotton wool at the first attempt and more difficult tinder like sawdust and paper are certainly achievable.
**Are there any special precautions or specific failures for fire steels?**
Not really, they don't like being soaked in water for long periods of time, but this is more an issue of long term storage than use. Obviously if you use a knife to strike them then basic cutting tool safety applies. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The pro of a fire steel over other lighters is that there's little that can break or be damaged from weather. Even if you lose the striker, a steel knife will work with the flint. However the con is that you only get a spark, not a steady flame. That means it needs to hit something that will ignite very easily. I use it to light my stoves (alcohol and isobutane) but I wouldn't want to try to start a fire with that and twigs. If you need to step it up to the next level, they make magnesium starters which you shave off some of the magnesium and hit that with a spark to light whatever the magnesium is in contact with.
I've only used a cheap "made in china" type, so I have no idea if others might be better. But we're only talking about a piece of metal so I'm not sure there's a big difference in quality. I'd suggest looking at quantity over quality, and get the largest size for the money. The sparks are from the flint being worn off, so a smaller flint will be worn away quicker.
To use, I prefer a handle on the flint to give me a better grip. You place the steel close to 90° against the flint, and point the flint towards the object you want to light. You can push the steel down the flint, but I like to pull the flint back away from the target since it gives me more control and there's less risk of blowing out what I'm trying to light. This is a fast scrape motion, not a strike. Maintain the right angle and pressure and sparks will fly easily.
I haven't tried the fire drill or piston, but keep in mind that you don't have highly accurate aim with the fire steel. This means it's much more trial and error to get the spark to hit just the right spot on your target.
The thing I like the best with fire steels is their reliability and durability. But because they don't provide a constant flame, I tend to keep matches as a backup. | I strike my fire steel with a piece of hacksaw blade. I have the added ability to either just strike/scrape the ferro rod, shave shavings off it into a tinder bundle to get more intense fire lighting sparks. I can use the striker to shave fat wood, or normal wood, which will in turn take less of a spark to ignite. I can attach a piece of paracord through the blades fixing hole so I can attach it to either the ferro rod, or keyring of some kind, or just to place as lanyard around the wrist for extra security so you don't use the striker when using. Also the teeth of the blade bite into the rod really well and will give you a lot of sparks with less effort, even when using cheaper harder material ferro rods that don't throw many sparks normally. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The pro of a fire steel over other lighters is that there's little that can break or be damaged from weather. Even if you lose the striker, a steel knife will work with the flint. However the con is that you only get a spark, not a steady flame. That means it needs to hit something that will ignite very easily. I use it to light my stoves (alcohol and isobutane) but I wouldn't want to try to start a fire with that and twigs. If you need to step it up to the next level, they make magnesium starters which you shave off some of the magnesium and hit that with a spark to light whatever the magnesium is in contact with.
I've only used a cheap "made in china" type, so I have no idea if others might be better. But we're only talking about a piece of metal so I'm not sure there's a big difference in quality. I'd suggest looking at quantity over quality, and get the largest size for the money. The sparks are from the flint being worn off, so a smaller flint will be worn away quicker.
To use, I prefer a handle on the flint to give me a better grip. You place the steel close to 90° against the flint, and point the flint towards the object you want to light. You can push the steel down the flint, but I like to pull the flint back away from the target since it gives me more control and there's less risk of blowing out what I'm trying to light. This is a fast scrape motion, not a strike. Maintain the right angle and pressure and sparks will fly easily.
I haven't tried the fire drill or piston, but keep in mind that you don't have highly accurate aim with the fire steel. This means it's much more trial and error to get the spark to hit just the right spot on your target.
The thing I like the best with fire steels is their reliability and durability. But because they don't provide a constant flame, I tend to keep matches as a backup. | **Why would one want one of these rather than a Storm Lighter?**
The advantage of a ferro rod is that it is simple, reliable and lasts a long time. There are no moving parts to break or fuel to run out. They will gradually wear down but they last a very long time for their weight and you can see how much material is left. Even if one breaks the broken parts should still be usable.
**Is one type or brand more effective than another?**
I've used various brands and generic ones, they all seem pretty much the same to me.
**Sizes are all over the map. Do these all work equally well? Is it just a matter of lifespan?**
Pretty much, a larger one will last longer and is perhaps marginally easier to use but there isn't a lot in it. I find the larger sizes (around 100mm x 10mm diameter) easiest to use.
**There are bare rods, rods on lanyards, and rods in handles. How does it matter?**
A lanyard is useful to stop it getting lost as you can attach it to your equipment. Some people keep them in a loop on their knife sheath so handle and/or lanyard makes them easier to get in and out. With a bare rod you can also make a handle of the size, shape and material you prefer. Some knife makers make ferro rod handles to match a particular knife.
A plain rod though is easier to pack in a survival kit and the smaller ones take up less space than most lighters.
**What is needed to make sparks with one of these rods? Will natural flint work as a striker?**
You need something reasonably hard with a well defined edge, the spine of a knife is often used or a short length of hacksaw blade. Abrasive materials like sandpaper or rough rocks work too as will a sharp flake of flint. Files work extremely well. They are also soft enough that you can use the edge of a knife as striker with little risk of damaging it.
**Do you "strike" or "scrape" a fire steel? How do you hold it?**
Usually the best technique is to rest the end of the rod on your tinder and scrape downwards. If you are using an abrasive strike it may be easier to strike it like a match. But it's really a case of what is easiest for you. It take a *bit* of practice to get the best results but it is much easier than a flint and steel or friction methods.
As mentioned in the comment below the main aspect of proper technique is to strike/scrape it with enough force to produce good sparks without disturbing your tinder. My preferred method is to place a wad of tinder on a flat surface then trap it with the end of the rod and scrape down onto the tinder rather than holding it above the tinder and trying to aim the sparks.
In general you want to apply moderate pressure with the striker and use a fairly slow scraping movement.
**Can you use less sensitive tinder than is needed for a fire drill or fire piston?**
They generate quite a lot of reasonably hot sparks so they tend to light tinder more quickly and easily than friction methods or natural flint and steel and you can light most things which could be reasonably called 'tinder'. They can also light flammable liquids. With care you can also scrape off small shavings of the rod without igniting them which can help ignition.
They will usually light cotton wool at the first attempt and more difficult tinder like sawdust and paper are certainly achievable.
**Are there any special precautions or specific failures for fire steels?**
Not really, they don't like being soaked in water for long periods of time, but this is more an issue of long term storage than use. Obviously if you use a knife to strike them then basic cutting tool safety applies. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The big plus with a firesteel is that you can pretty much do what you want to it, including soaking the thing in ice cold water, and it'll still work as well as before. The big downside is it's just sparks, so it's harder to build a fire.
However, with practice, it's not that hard and does provide a good backup if your matches get soaked through and your lighter gets damaged.
In terms of specific questions:
* I have two or three brands and I see no discernible difference between them.
* The bigger the better - the thicker it is, the longer it will last before being worn down.
* Any flat blade will generally do the trick, though if you use a sharp knife bear in mind it'll get worn down quite quickly.
* I prefer rods on handles - it makes it a lot easier to hold whilst using.
* You scrape rather than strike, still relatively fast. However, I've found good pressure and angle is much more important than speed. When practicing, go slowly - you'll improve your technique and be surprised how many sparks you can create this way.
* No real specific precautions you need to bear in mind, just the general ones when you're dealing with fire! | I strike my fire steel with a piece of hacksaw blade. I have the added ability to either just strike/scrape the ferro rod, shave shavings off it into a tinder bundle to get more intense fire lighting sparks. I can use the striker to shave fat wood, or normal wood, which will in turn take less of a spark to ignite. I can attach a piece of paracord through the blades fixing hole so I can attach it to either the ferro rod, or keyring of some kind, or just to place as lanyard around the wrist for extra security so you don't use the striker when using. Also the teeth of the blade bite into the rod really well and will give you a lot of sparks with less effort, even when using cheaper harder material ferro rods that don't throw many sparks normally. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The pro of a fire steel over other lighters is that there's little that can break or be damaged from weather. Even if you lose the striker, a steel knife will work with the flint. However the con is that you only get a spark, not a steady flame. That means it needs to hit something that will ignite very easily. I use it to light my stoves (alcohol and isobutane) but I wouldn't want to try to start a fire with that and twigs. If you need to step it up to the next level, they make magnesium starters which you shave off some of the magnesium and hit that with a spark to light whatever the magnesium is in contact with.
I've only used a cheap "made in china" type, so I have no idea if others might be better. But we're only talking about a piece of metal so I'm not sure there's a big difference in quality. I'd suggest looking at quantity over quality, and get the largest size for the money. The sparks are from the flint being worn off, so a smaller flint will be worn away quicker.
To use, I prefer a handle on the flint to give me a better grip. You place the steel close to 90° against the flint, and point the flint towards the object you want to light. You can push the steel down the flint, but I like to pull the flint back away from the target since it gives me more control and there's less risk of blowing out what I'm trying to light. This is a fast scrape motion, not a strike. Maintain the right angle and pressure and sparks will fly easily.
I haven't tried the fire drill or piston, but keep in mind that you don't have highly accurate aim with the fire steel. This means it's much more trial and error to get the spark to hit just the right spot on your target.
The thing I like the best with fire steels is their reliability and durability. But because they don't provide a constant flame, I tend to keep matches as a backup. | We use both. It is not difficult to light a fire with a ferrocerium rod especially if you have pine trees around as we do. A bit of sap from one of them on your shavings, cotton balls, spanish moss and one strike from the rod will start the fire. No sap? Then we also carry a small jar of vaseline. Both are overkill but help when you must light a fire in the pouring rain or high humidity. Small shavings can be made on site and charcloth is also usable with a firestick.
Two is one and one is none...Equipment fails under special conditions and that is why we do not skimp on firestarting ways. We have started fires using a magnifying lens which we needed when the guy carrying the firemaking tools decided to fall into the lake and drench our equipment. Only the firesteel and the magnifying glass worked then.
They are also a lot of fun but recommend watching a video or two to see the proper hand motions. Keep the stick when striking (scraping is the correct word), right on top or in the target. All of which you have probably done by now. |
1,431 | [Fire steels](http://en.wikipedia.org/wiki/Ferrocerium), ferrocerium rods -- oversized versions of the "flint" in a lighter or torch starter, are an apparently popular survival/backwoods fire starting method.
* Why would one want one of these rather than a [Storm Lighter](https://i.stack.imgur.com/gmcYM.jpg)?
* Is one type or brand more effective than another?
* Sizes are [all over the map](https://i.stack.imgur.com/MMwc4.jpg). Do these all work equally well? Is it just a matter of lifespan?
* There are bare rods, rods on lanyards, and rods in handles. How does it matter?
* What is needed to make sparks with one of these rods? Will natural flint work as a striker?
* Do you "strike" or "scrape" a fire steel? How do you hold it?
* Can you use less sensitive tinder than is needed for a fire drill or fire piston?
* Are there any special precautions or specific failures for fire steels? | 2012/05/06 | [
"https://outdoors.stackexchange.com/questions/1431",
"https://outdoors.stackexchange.com",
"https://outdoors.stackexchange.com/users/133/"
] | The big plus with a firesteel is that you can pretty much do what you want to it, including soaking the thing in ice cold water, and it'll still work as well as before. The big downside is it's just sparks, so it's harder to build a fire.
However, with practice, it's not that hard and does provide a good backup if your matches get soaked through and your lighter gets damaged.
In terms of specific questions:
* I have two or three brands and I see no discernible difference between them.
* The bigger the better - the thicker it is, the longer it will last before being worn down.
* Any flat blade will generally do the trick, though if you use a sharp knife bear in mind it'll get worn down quite quickly.
* I prefer rods on handles - it makes it a lot easier to hold whilst using.
* You scrape rather than strike, still relatively fast. However, I've found good pressure and angle is much more important than speed. When practicing, go slowly - you'll improve your technique and be surprised how many sparks you can create this way.
* No real specific precautions you need to bear in mind, just the general ones when you're dealing with fire! | We use both. It is not difficult to light a fire with a ferrocerium rod especially if you have pine trees around as we do. A bit of sap from one of them on your shavings, cotton balls, spanish moss and one strike from the rod will start the fire. No sap? Then we also carry a small jar of vaseline. Both are overkill but help when you must light a fire in the pouring rain or high humidity. Small shavings can be made on site and charcloth is also usable with a firestick.
Two is one and one is none...Equipment fails under special conditions and that is why we do not skimp on firestarting ways. We have started fires using a magnifying lens which we needed when the guy carrying the firemaking tools decided to fall into the lake and drench our equipment. Only the firesteel and the magnifying glass worked then.
They are also a lot of fun but recommend watching a video or two to see the proper hand motions. Keep the stick when striking (scraping is the correct word), right on top or in the target. All of which you have probably done by now. |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | **SO:** 599 to 43
*approximately a 9 up to 1 down on average*
**SU:** 57 to 3
*approximately a 10 up to 1 down on average*
**SF:** 7 to 1
*precisely a a 7 up to 1 down on average*
**META:** 206 to 44
*approximately 4 up to 1 down on average*
**FAMILY:** 869 to 91
*approximately a 9 up to 1 down on average*
Some Highlights... I'm probably **WAY TOO NICE!** I would be at over 2K points here on META if I did not vote down 43 times though... I also think that I'm more likely to vote down on META because the rep doesn't mean as much to me here as stackoverflow itself at this time. | SO: 156-1
SU: 20-0 |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | * SuperUser - 28.333(repeating) with a current rep of just over 1,000
* ServerFault - 8 with a current rep of 319
* StackOverflow - 8.7362637362637362637362637362637 with a current rep of almost 13,000
* Meta - 19.55 with a current rep almost to 5,000
I think once people hit the 3,000 mark and then the 10,000 mark you will start to see rather drastic changes in their voting patterns which would allow for more down votes. I know that was the case with me. Once I hit 10k I stopped caring much about my rep in StackOverflow and was much more willing to cast downvotes on things since I no longer felt like I needed to keep getting a higher and higher score.
I should also note that the longer you are a member, the higher your ratios are going to be (it will almost never shrink) because it is almost insane to imagine someone not named Rich B casting more downvotes per day than upvotes. | I've been more or less active on SO since public beta started in September, and I currently have 17.8k rep. I don't *think* I've become bitter with age; my upvote-to-downvote ratio is 1742:27 = 64.52.
I've explained my reasoning for downvotes [here](https://meta.stackexchange.com/questions/2451/why-do-you-cast-downvotes-on-answers/2455#2455); basically, I downvote only in extreme circumstances.
I upvote whenever I like an answer or question, which happens quite a lot. |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | * SuperUser - 28.333(repeating) with a current rep of just over 1,000
* ServerFault - 8 with a current rep of 319
* StackOverflow - 8.7362637362637362637362637362637 with a current rep of almost 13,000
* Meta - 19.55 with a current rep almost to 5,000
I think once people hit the 3,000 mark and then the 10,000 mark you will start to see rather drastic changes in their voting patterns which would allow for more down votes. I know that was the case with me. Once I hit 10k I stopped caring much about my rep in StackOverflow and was much more willing to cast downvotes on things since I no longer felt like I needed to keep getting a higher and higher score.
I should also note that the longer you are a member, the higher your ratios are going to be (it will almost never shrink) because it is almost insane to imagine someone not named Rich B casting more downvotes per day than upvotes. | 12.88 for me on Stackoverflow. That puts me in the realm of the "nice," right? |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | **SO:** 599 to 43
*approximately a 9 up to 1 down on average*
**SU:** 57 to 3
*approximately a 10 up to 1 down on average*
**SF:** 7 to 1
*precisely a a 7 up to 1 down on average*
**META:** 206 to 44
*approximately 4 up to 1 down on average*
**FAMILY:** 869 to 91
*approximately a 9 up to 1 down on average*
Some Highlights... I'm probably **WAY TOO NICE!** I would be at over 2K points here on META if I did not vote down 43 times though... I also think that I'm more likely to vote down on META because the rep doesn't mean as much to me here as stackoverflow itself at this time. | I knew I was generous with up-votes, but didn't think I was that stingy with down-votes.
SF: 521-1
SO: 129-0
SU: 122-0
Meta: 74-0
plus a handful flagged for spam and moderator attention. |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | Personally I don't think people down vote enough, I see way to many answers that are just plain wrong or mis-informed that don't get down voted and leave bad advice or suggestions that someone that is new won't know is bad advice or suggestion. And there will be people with 10K or more reputation that post answers and still don't down vote the empirically bad answers.
I up vote the answers that are most importantly correct, and then well thought out and detailed. But I feel I am the only critic some times down voting all the wrong answers that don't even address the question at hand because someone answered without reading for comprehension. C# answers on Java questions, and vice versa are good examples.
**What does meta think?** | SO: 369 up, 26 down
MetaSO: 9 up
SU: 9 up, 1 down
SF: none
I never took myself to be such a positive guy! I guess I just only downvote when I think an answer is really bad advice. |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | Using the [Stack Exchange Data Explorer](https://data.stackexchange.com/), it's pretty easy to obtain some more up-to-date sitewide figures.
[This simple query](https://data.stackexchange.com/stackoverflow/query/66779/vote-stats) lists how many votes of each type were cast. | StackOverflow: 9.4:1 |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | Personally I don't think people down vote enough, I see way to many answers that are just plain wrong or mis-informed that don't get down voted and leave bad advice or suggestions that someone that is new won't know is bad advice or suggestion. And there will be people with 10K or more reputation that post answers and still don't down vote the empirically bad answers.
I up vote the answers that are most importantly correct, and then well thought out and detailed. But I feel I am the only critic some times down voting all the wrong answers that don't even address the question at hand because someone answered without reading for comprehension. C# answers on Java questions, and vice versa are good examples.
**What does meta think?** | I'm shocked! That would be 3.39 for me on so. I'm a negative bastard! |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | Using the [Stack Exchange Data Explorer](https://data.stackexchange.com/), it's pretty easy to obtain some more up-to-date sitewide figures.
[This simple query](https://data.stackexchange.com/stackoverflow/query/66779/vote-stats) lists how many votes of each type were cast. | On StackOverflow:
>
> 1201:94
>
>
>
12.777
I'm a nice guy. |
7,401 | >
> **Possible Duplicate:**
>
> [Tweet question and answer](https://meta.stackexchange.com/questions/3926)
>
>
>
>
Whenever I ask a question, I end up tweeting it to expose it to the people that follow me on twitter, many of which are SO users and in the same field. It would be nice to have a "Tweet this question" link after creating a question to automate the process. | 2009/07/20 | [
"https://meta.stackexchange.com/questions/7401",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/1786/"
] | **SO:** 599 to 43
*approximately a 9 up to 1 down on average*
**SU:** 57 to 3
*approximately a 10 up to 1 down on average*
**SF:** 7 to 1
*precisely a a 7 up to 1 down on average*
**META:** 206 to 44
*approximately 4 up to 1 down on average*
**FAMILY:** 869 to 91
*approximately a 9 up to 1 down on average*
Some Highlights... I'm probably **WAY TOO NICE!** I would be at over 2K points here on META if I did not vote down 43 times though... I also think that I'm more likely to vote down on META because the rep doesn't mean as much to me here as stackoverflow itself at this time. | Stack Overflow: 331 Up votes to 7 Downvotes
So around 47 to 1 |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | **They are too heavy to go on land.**
These mechs have seriously thick armor. The weight of this metal is balanced by gas filled spaces. The underwater mechs are neutrally buoyant. Because of their mass they have inertia but they do not need to constantly fight the acceleration of gravity. They can walk along the bottom of the ocean fine but their servos would not be able to carry them on land. | **They're not as good as tanks**
Tanks are maneuverable on all sorts of terrain, can be scaled up much better than anything with gangly limbs, have a much more stable shape and are probably much cheaper to manufacture than an equivalent mech, which requires more motors, servos, etc. |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | **They are too heavy to go on land.**
These mechs have seriously thick armor. The weight of this metal is balanced by gas filled spaces. The underwater mechs are neutrally buoyant. Because of their mass they have inertia but they do not need to constantly fight the acceleration of gravity. They can walk along the bottom of the ocean fine but their servos would not be able to carry them on land. | **First, for the biological part**
We are starting with (presumably) as our base a subspecies of this monster which has adapted to marine life. Over this short a period that is pretty remarkable and suggests a very fast rate of mutation. Adaptations can include things like:
* streamlined hydrodynamic shape to improve speed underwater. For this reason I suggest the mechs be 15' feet *long* not *tall*. This will cause a tradeoff on land. Just look at Crocodiles: they move fast as lightning in the water but are very slow and ineffective predators on land.
* a shift from limbs to fins or flippers and tail flukes
* either develop the capacity to 1- hold breath for a very long time like whales or 2- evolve gills to to get oxygen from the water.
Option 2 would explain why this specific model of bio-mech will not work on land. The living part of it wouldn't be able to breathe. Option 2 would also allow this creature to dive to depths well beyond what a human diver even in a suit can survive.
**Now, as for the mechanical part**
Submarines are good at hunting other submarines, but marine life is better at detecting other marine predators and prey. Electrosense, the ability to detect minute changes in water pressure which suggest the approach of a fast moving animal, keen eyesight, echolocation.. a submarine just has sonar and has to be careful how and when it uses it.
By the same token, firing a torpedo or anti-ship missile at wildlife is... well it is significant and ludicrous overkill, and a good way to run out of missiles and money. Something armed with weapons more suitable to combating an underwater predator though, and mounted on a bio-mech is a feasible way to fight a war. The submarine's role in this mode of warfare would essentially be to act as a tender / base of operations for teams of these biomechs. |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | **They are too heavy to go on land.**
These mechs have seriously thick armor. The weight of this metal is balanced by gas filled spaces. The underwater mechs are neutrally buoyant. Because of their mass they have inertia but they do not need to constantly fight the acceleration of gravity. They can walk along the bottom of the ocean fine but their servos would not be able to carry them on land. | Have you noticed that sea animals get a lot bigger than terrestrial animals? Buoyancy makes it possible to grow a lot bigger underwater due to the lesser need to support your own weight. For more details, see the "square-cube law," the effects of which are mitigated by being underwater.
That's been mentioned by a couple people already though. The thing I wanted to add is that you don't need to frame the question as "why don't mechs work on land." You can also frame it as "why are there better options on land." Projectiles, for instance, go further faster through air than ocean water, especially deep down where water pressure is high. This is true for energy weapons as well. Maybe terrestrial arsenals have a large and futuristic array of machine/rail/Gatling/laser/etc. guns that perform very well above ground but poorly underwater.
Air support is also a thing for armies. Perhaps individual soldiers can call in bombing raids, missile strikes, and so on, but underwater you've got to carry that stuff with you. So now you need the mech just to hold all of your high explosives.
So, in summary:
1. It's easier to build large structurally sound mechs for underwater use than it is for terrestrial use.
2. Projectile weapons perform well above water, but poorly underwater.
3. Terrestrial armies can call in air support, but undersea fighters have to carry all their firepower with them.
Edit: One other thing just occurred to me. You have to be in a suit deep underwater anyway. Since it's obligatory, it may as well be useful. Hopefully some combination of those reasons will suffice. |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | Mimicry
-------
The monsters try to avoid military and attack unarmed civilians. Submarines and destroyers are very distinctive; so, the monsters can identify them from far away and just go around them in favor of easier targets on the shore, but the mechs are made to move, sound, and (thanks to organic parts) smell like a monster. So, these mechs go into the water and perform various lures to get the monsters to come to it by doing everything from faking distress to mating dances. By the time the monster gets close enough to realize its mistake, it's already in weapons range.
Once these monsters are up on land, it is a different story. They only come up onto land to hunt, and this means they are looking for food, not companionship... so, they don't take nearly as much coxing to get them to come to you. In fact, making your soldiers on land look as much like a normal person as possible is the best lure you could use to make sure they come towards your guns instead of going around to hit your unguarded population centers. | **First, for the biological part**
We are starting with (presumably) as our base a subspecies of this monster which has adapted to marine life. Over this short a period that is pretty remarkable and suggests a very fast rate of mutation. Adaptations can include things like:
* streamlined hydrodynamic shape to improve speed underwater. For this reason I suggest the mechs be 15' feet *long* not *tall*. This will cause a tradeoff on land. Just look at Crocodiles: they move fast as lightning in the water but are very slow and ineffective predators on land.
* a shift from limbs to fins or flippers and tail flukes
* either develop the capacity to 1- hold breath for a very long time like whales or 2- evolve gills to to get oxygen from the water.
Option 2 would explain why this specific model of bio-mech will not work on land. The living part of it wouldn't be able to breathe. Option 2 would also allow this creature to dive to depths well beyond what a human diver even in a suit can survive.
**Now, as for the mechanical part**
Submarines are good at hunting other submarines, but marine life is better at detecting other marine predators and prey. Electrosense, the ability to detect minute changes in water pressure which suggest the approach of a fast moving animal, keen eyesight, echolocation.. a submarine just has sonar and has to be careful how and when it uses it.
By the same token, firing a torpedo or anti-ship missile at wildlife is... well it is significant and ludicrous overkill, and a good way to run out of missiles and money. Something armed with weapons more suitable to combating an underwater predator though, and mounted on a bio-mech is a feasible way to fight a war. The submarine's role in this mode of warfare would essentially be to act as a tender / base of operations for teams of these biomechs. |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | Have you noticed that sea animals get a lot bigger than terrestrial animals? Buoyancy makes it possible to grow a lot bigger underwater due to the lesser need to support your own weight. For more details, see the "square-cube law," the effects of which are mitigated by being underwater.
That's been mentioned by a couple people already though. The thing I wanted to add is that you don't need to frame the question as "why don't mechs work on land." You can also frame it as "why are there better options on land." Projectiles, for instance, go further faster through air than ocean water, especially deep down where water pressure is high. This is true for energy weapons as well. Maybe terrestrial arsenals have a large and futuristic array of machine/rail/Gatling/laser/etc. guns that perform very well above ground but poorly underwater.
Air support is also a thing for armies. Perhaps individual soldiers can call in bombing raids, missile strikes, and so on, but underwater you've got to carry that stuff with you. So now you need the mech just to hold all of your high explosives.
So, in summary:
1. It's easier to build large structurally sound mechs for underwater use than it is for terrestrial use.
2. Projectile weapons perform well above water, but poorly underwater.
3. Terrestrial armies can call in air support, but undersea fighters have to carry all their firepower with them.
Edit: One other thing just occurred to me. You have to be in a suit deep underwater anyway. Since it's obligatory, it may as well be useful. Hopefully some combination of those reasons will suffice. | ### Close range combat
The monsters hide in caves in the sea bottom. When they sense the presence of a submarine they hide behind rocks and they prefer to move in narrow gorges between underwater mountain. The only way to engage them is close range combat, obviously they move faster than mechs, but since they chose narrow spaces and the submarines patrol the empty water overhead they can be encircled.
### Close range combat 2
Underwater the only available weapons are torpedoes and they are not as fast as missiles. Bullets are useless, speers short ranged. With few alternatives the possibility of close range combat becomes more likely.
### Balance
Notwithstanding all the improvements in robotics balance of bipedal machine is still delicate. Especially for a machine that should be capable of sudden changes of speed and direction and should also be able to move sideways while moving the arms for a fight. The water surronding the mech sustains it a little bit, making balance easier. |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | Another possible reason would be fuel. A giant mech is going to require a metric crap-ton of energy to move around. Perhaps the biological components of the mechs are developed from the monsters themselves, and generate large amounts of electricity from seawater. (I don't know the science, but I'm sure there's something involving high-electrolyte water or trace metals suspended in saltwater that will suffice. Or maybe they filter trace radioactive elements from the water and use them for micro-fusion. Or...)
Thus, a mech *can't* operate on land, because it can't carry enough seawater around to operate for more than a couple of minutes. But when immersed *in the sea*, there's no such thing as running out of seawater fuel. Functionally, this is the same as an air-breathing animal needing to stay on the land -- we use oxygen specifically to generate energy, and need a continuous supply of it. The mechs use seawater to generate energy, and need a continuous supply of it.
(This could also lead to a cool story idea where the monsters discover this weakness, and start deliberately throwing/pushing the mechs above the surface of the water to weaken or disable them. Like fighting a human in a river and shoving their face underwater to take away their oxygen supply, only in reverse.) | Missiles.
In the war between weapon and armor the anti-tank missile has prevailed. Mecha are basically a tanks that trade some armor for better handling of some terrain.
However, there is no underwater equivalent to the infantry anti-tank missile. There are torpedoes but they are a lot bigger and don't move nearly as fast--your mecha have point defense systems that can stop torpedoes. (Yes, there are supercavitating torpedoes, but during the supercavitating phase they are blind. You either use them as unguided weapons or you use the supercavitating capability to get them close to the target and then drop to normal torpedo speeds to actually attack.) |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | Underwater mechas are already in use
------------------------------------
There are many tasks which need to be performed by workers working underwater; tightening bolts on pipelines for example.
People don't do well underwater, because water is heavy and if you go deep enough the weight will squish you. (Yes, it is more complicated than that; but the point is, unprotected people don't do well underwater.)
Robots have not yet really progressed to the point where one can just tell a robot to go down there and tighten the bolts.
That's why people have developed what is called [atmospheric diving suits](https://en.wikipedia.org/wiki/Atmospheric_diving_suit), which are, to use Wikipedia's words, *"one-person articulated submersibles"* *"which resemble a suit of armour"*. Some atmospheric diving suits even incorporate motors for power and propulsion. In other words, they are real-life mechas.
>
> *Atmospheric diving suits in current use include the Newtsuit, Exosuit, Hardsuit and the WASP, all of which are self-contained hard suits that incorporate propulsion units. The Hardsuit is constructed from cast aluminum (forged aluminum in a version constructed for the US Navy for submarine rescue); the upper hull is made from cast aluminum,[clarification needed] while the bottom dome is machined aluminum. The WASP is of glass-reinforced plastic (GRP) body tube construction.* ([Wikipedia](https://en.wikipedia.org/w/index.php?title=Atmospheric_diving_suit&oldid=1035795079))
>
>
>
[](https://commons.wikimedia.org/wiki/File:Navy_Diver4.jpg)
*Chief Navy Diver Daniel Jackson completes a successful certification dive of the Atmospheric Diving System (ADS) aboard the special mission charter ship M/V Kellie Chouest off the coast of La Jolla, Calif. Photograph by the U.S. federal government, [available on Wikimedia](https://commons.wikimedia.org/wiki/File:Navy_Diver4.jpg). Public domain.*
>
> *[Atmospheric diving suits] can be used for very deep dives for long periods without the need for decompression, and eliminate the majority of physiological dangers associated with deep diving. Divers do not even need to be skilled swimmers.* ([Wikipedia](https://en.wikipedia.org/wiki/Diving_suit))
>
>
> | ### Close range combat
The monsters hide in caves in the sea bottom. When they sense the presence of a submarine they hide behind rocks and they prefer to move in narrow gorges between underwater mountain. The only way to engage them is close range combat, obviously they move faster than mechs, but since they chose narrow spaces and the submarines patrol the empty water overhead they can be encircled.
### Close range combat 2
Underwater the only available weapons are torpedoes and they are not as fast as missiles. Bullets are useless, speers short ranged. With few alternatives the possibility of close range combat becomes more likely.
### Balance
Notwithstanding all the improvements in robotics balance of bipedal machine is still delicate. Especially for a machine that should be capable of sudden changes of speed and direction and should also be able to move sideways while moving the arms for a fight. The water surronding the mech sustains it a little bit, making balance easier. |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | ### Close range combat
The monsters hide in caves in the sea bottom. When they sense the presence of a submarine they hide behind rocks and they prefer to move in narrow gorges between underwater mountain. The only way to engage them is close range combat, obviously they move faster than mechs, but since they chose narrow spaces and the submarines patrol the empty water overhead they can be encircled.
### Close range combat 2
Underwater the only available weapons are torpedoes and they are not as fast as missiles. Bullets are useless, speers short ranged. With few alternatives the possibility of close range combat becomes more likely.
### Balance
Notwithstanding all the improvements in robotics balance of bipedal machine is still delicate. Especially for a machine that should be capable of sudden changes of speed and direction and should also be able to move sideways while moving the arms for a fight. The water surronding the mech sustains it a little bit, making balance easier. | Missiles.
In the war between weapon and armor the anti-tank missile has prevailed. Mecha are basically a tanks that trade some armor for better handling of some terrain.
However, there is no underwater equivalent to the infantry anti-tank missile. There are torpedoes but they are a lot bigger and don't move nearly as fast--your mecha have point defense systems that can stop torpedoes. (Yes, there are supercavitating torpedoes, but during the supercavitating phase they are blind. You either use them as unguided weapons or you use the supercavitating capability to get them close to the target and then drop to normal torpedo speeds to actually attack.) |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | **Heat**
Mechs are inefficient temperature-wise, being submerged in water helps them dissipate heat quickly, which allows them to operate longer than few minutes on land before overheating | 1. High value of gravity of the planet (1.5-1.7 of Earth gravity, for example).
2. Microorganisms (e.g. [Ideonella sakaiensis](https://en.wikipedia.org/wiki/Ideonella_sakaiensis)) or other substances in the atmosphere that cause very rapid corrosion of metal (or any specific things in the robots).
3. The land has a lot of [karst](https://en.wikipedia.org/wiki/Karst) or other (ice, etc.) caves and caverns (like in the Lem's ["Fiasco"](https://en.wikipedia.org/wiki/Fiasco_(novel)) in the beginning on the Titan), and swamps, and geysers - as a result, it is a dangerous environment for heavy robots. |
210,946 | In my world, the planet (which is not Earth, but is suitably Earth-like) has been besieged by deadly monsters for about 1000 years. Their initial attack lead to an apocalyptic scenario which took humanity hundreds of years to fully recover from. Since then, humanity has banded into one large empire/federation and another apocalypse has been averted, but it requires periodic military excursions into the wild to prevent any of these monsters from entering city limits.
The most dangerous variants of these monsters are the ones that dwell in the sea. To combat them, part mechanical part biological mechs were built. They are 15 ft tall and fight alongside small and medium-sized submarines. They are very effective in their role, but are not used in land-based operations. Instead, soldiers either fight with something like the exoskeleton from the movie Elysium (Here:  or just have simple ballistic vests that protect them from possible friendly fire.
My question is: why would these mechs be limited to water combat if they have been so effective in fighting monsters? | 2021/08/25 | [
"https://worldbuilding.stackexchange.com/questions/210946",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/86590/"
] | **They are too heavy to go on land.**
These mechs have seriously thick armor. The weight of this metal is balanced by gas filled spaces. The underwater mechs are neutrally buoyant. Because of their mass they have inertia but they do not need to constantly fight the acceleration of gravity. They can walk along the bottom of the ocean fine but their servos would not be able to carry them on land. | Something about the biological portions of the mech synergizes with the shape. If the parts are from monsters, then the closer the incorporated part's image is to their original body part on the monster (platonian ideal), then the greater the effect.
For that reason, any kind of mech that resembles a living creature is more effective than the same materials but on a soulless submarine. |
267,575 | In the book “Educated” by Tara Westover, chapter 5, what does *scrap* mean in the following?
>
> Tony and Shawn had left the mountain, but they’d left to do what my father had taught them to do: drive semis, weld, scrap.
>
>
> | 2020/12/04 | [
"https://ell.stackexchange.com/questions/267575",
"https://ell.stackexchange.com",
"https://ell.stackexchange.com/users/10310/"
] | It most likely refers to working with scrap metal. This could include collecting scrap metal, collecting items (like cars) to make into scrap metal, or disposing of scrap metal. The aim is usually to make money. | "scrap" can also mean "fight" or "argue", usually implying a not too serious conflict. This **might** mean that the father had taught Tony and Shawn to drive semis, weld, and fight. This is a little more plausible because "scrap" as a verb meaning ."discard" is transitive, and should specify what is being scrapped, and if the meaning is "work with scrap metal" then "scrap" is not a normal verb to use, it is normally a noun or an adjective in that context.
However, the tone seems informal so one cannot be sure that non-standared usage will not be present. Without more context, one can only guess. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | A larger than minimum smoothing capacitor on the output of a transformer and rectifier will give you lower ripple, which is a plus. It's a small plus however, as even doubling the size of the capacitor will only (roughly) halve the ripple. Anything downstream of a large capacitor will need to have significant Power Supply Rejection Ratio (PSRR) to cope with the ripple. There are cheaper ways of improving this by a factor of two than doubling the size of the Big Filtering Capacitor (BFC).
The downside to a larger BFC is that it will draw larger, shorter current pulses from the input transformer and rectifier.
This can cause a number of problems, though most are small, or can be mitigated.
a) Higher electromagnetic interference generation, due to larger current pulses, and higher currents being switched off in the diodes.
b) Slightly hotter diodes and transformer, due to larger RMS current.
c) Poorer input power factor.
A sniff of inductance somewhere in the supply (AC input, transformer leakage inductance, post transformer or post diode) will reduce the magnitude and extend the length of the rectifier pulses, improving all of the above. | On the face of bigger is better for reasons that are well documented elsewhere.If the cap gets really big there will be problems with inrush current .On a small power supply the transformer should keep this down to a reasonable value .When rectifying mains into a cap filter the peak currents in the diodes can be several times the average DC output current .This is well documented elsewhere.This peakiness of diode current causes poor power factor and bad line current THD .If your source impedence is low the bigger cap will make this worse .Generally you can use the bigger cap on a small transformer based system without having to add any other parts.Larger systems can be made to work well by employing a line reactor on the AC or a small choke on the DC .If you are putting a very large smoothing cap on the output of a buck convertor there is a risk of instability which may need a small inductor to mitigate by divorcing the big cap. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | Here's another point: many modern converters are protected against shorts or overloads in the output circuit. Such protection is a must for lab PSUs and a nice feature for all PSUs with connectors, since the ability to connect different loads increases the risk of shorts and overloads.
Having a big cap on the output reduces the effectiveness of such protection, since more energy is available to do the damage before the protection cuts the power off. | Larger capacitors also have more parasitics (eg equiv. series resistance and inductance.) This is what "slows them down" so to speak. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | Note: my interpretation of the OPs post is we are talking about capacitors on the output of voltage regulators, some other posts seem to assume the asker is talking about capacitors on rectifiers.
The main downside of a bigger capacitor is that the switch on rise time and switch off fall time will be greater. That means more stress on the regulator during startup and in extreme cases may even cause an overcurrent shutdown of the regulator. It can also cause problems for loads which don't handle undervoltage very well.
Having said that I don't think there is any point trying to micromanage the size of such capacitors. In most cases allowing a generous margin (a factor of 2 or more) over what you think you need is unlikely to be a problem. | Larger capacitors also have more parasitics (eg equiv. series resistance and inductance.) This is what "slows them down" so to speak. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | A larger than minimum smoothing capacitor on the output of a transformer and rectifier will give you lower ripple, which is a plus. It's a small plus however, as even doubling the size of the capacitor will only (roughly) halve the ripple. Anything downstream of a large capacitor will need to have significant Power Supply Rejection Ratio (PSRR) to cope with the ripple. There are cheaper ways of improving this by a factor of two than doubling the size of the Big Filtering Capacitor (BFC).
The downside to a larger BFC is that it will draw larger, shorter current pulses from the input transformer and rectifier.
This can cause a number of problems, though most are small, or can be mitigated.
a) Higher electromagnetic interference generation, due to larger current pulses, and higher currents being switched off in the diodes.
b) Slightly hotter diodes and transformer, due to larger RMS current.
c) Poorer input power factor.
A sniff of inductance somewhere in the supply (AC input, transformer leakage inductance, post transformer or post diode) will reduce the magnitude and extend the length of the rectifier pulses, improving all of the above. | Note: my interpretation of the OPs post is we are talking about capacitors on the output of voltage regulators, some other posts seem to assume the asker is talking about capacitors on rectifiers.
The main downside of a bigger capacitor is that the switch on rise time and switch off fall time will be greater. That means more stress on the regulator during startup and in extreme cases may even cause an overcurrent shutdown of the regulator. It can also cause problems for loads which don't handle undervoltage very well.
Having said that I don't think there is any point trying to micromanage the size of such capacitors. In most cases allowing a generous margin (a factor of 2 or more) over what you think you need is unlikely to be a problem. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | A larger than minimum smoothing capacitor on the output of a transformer and rectifier will give you lower ripple, which is a plus. It's a small plus however, as even doubling the size of the capacitor will only (roughly) halve the ripple. Anything downstream of a large capacitor will need to have significant Power Supply Rejection Ratio (PSRR) to cope with the ripple. There are cheaper ways of improving this by a factor of two than doubling the size of the Big Filtering Capacitor (BFC).
The downside to a larger BFC is that it will draw larger, shorter current pulses from the input transformer and rectifier.
This can cause a number of problems, though most are small, or can be mitigated.
a) Higher electromagnetic interference generation, due to larger current pulses, and higher currents being switched off in the diodes.
b) Slightly hotter diodes and transformer, due to larger RMS current.
c) Poorer input power factor.
A sniff of inductance somewhere in the supply (AC input, transformer leakage inductance, post transformer or post diode) will reduce the magnitude and extend the length of the rectifier pulses, improving all of the above. | Larger capacitors also have more parasitics (eg equiv. series resistance and inductance.) This is what "slows them down" so to speak. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | As far as caps go, there are two competing requirements:long-term (ripple) and instantaneous (spike). A big electrolytic can give you the former but not the latter. Generally you parallel your large electrolytic with a smaller 0.1uF capable of supplying that instantaneous spike whilst the electrolytic lumbers into action. Or the 0.1uF may be for local decoupling to stabilise that regulator. If the specified capacitor is actually 0.1uF or smaller, then the intention of the capacitor is to supply small amounts of charge very fast. Do not replace this with a bigger electrolytic - that's definitely a case where larger is worse not better.
Going past that, you'll have to tell us what kind of regulators you're dealing with. If it's just a basic linear regulator then it doesn't really matter. If you have a switching regulator though, the capacitor will affect the resonant frequency of the switcher, so be very careful there. | On the face of bigger is better for reasons that are well documented elsewhere.If the cap gets really big there will be problems with inrush current .On a small power supply the transformer should keep this down to a reasonable value .When rectifying mains into a cap filter the peak currents in the diodes can be several times the average DC output current .This is well documented elsewhere.This peakiness of diode current causes poor power factor and bad line current THD .If your source impedence is low the bigger cap will make this worse .Generally you can use the bigger cap on a small transformer based system without having to add any other parts.Larger systems can be made to work well by employing a line reactor on the AC or a small choke on the DC .If you are putting a very large smoothing cap on the output of a buck convertor there is a risk of instability which may need a small inductor to mitigate by divorcing the big cap. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | On the face of bigger is better for reasons that are well documented elsewhere.If the cap gets really big there will be problems with inrush current .On a small power supply the transformer should keep this down to a reasonable value .When rectifying mains into a cap filter the peak currents in the diodes can be several times the average DC output current .This is well documented elsewhere.This peakiness of diode current causes poor power factor and bad line current THD .If your source impedence is low the bigger cap will make this worse .Generally you can use the bigger cap on a small transformer based system without having to add any other parts.Larger systems can be made to work well by employing a line reactor on the AC or a small choke on the DC .If you are putting a very large smoothing cap on the output of a buck convertor there is a risk of instability which may need a small inductor to mitigate by divorcing the big cap. | Larger capacitors also have more parasitics (eg equiv. series resistance and inductance.) This is what "slows them down" so to speak. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | As far as caps go, there are two competing requirements:long-term (ripple) and instantaneous (spike). A big electrolytic can give you the former but not the latter. Generally you parallel your large electrolytic with a smaller 0.1uF capable of supplying that instantaneous spike whilst the electrolytic lumbers into action. Or the 0.1uF may be for local decoupling to stabilise that regulator. If the specified capacitor is actually 0.1uF or smaller, then the intention of the capacitor is to supply small amounts of charge very fast. Do not replace this with a bigger electrolytic - that's definitely a case where larger is worse not better.
Going past that, you'll have to tell us what kind of regulators you're dealing with. If it's just a basic linear regulator then it doesn't really matter. If you have a switching regulator though, the capacitor will affect the resonant frequency of the switcher, so be very careful there. | From Andy akas comment:
If the supply you are using has [specific output capacitor requirements](http://www.ti.com/product/lm1117?keyMatch=lm1117&tisearch=Search-EN-Everything), then make sure you follow them. For all these types of regulator linked (LDO), there is usually a minimum capacitance only. (search the datasheet for ESR).
If you are using a switch-mode regulator, then the output capacitor (in current mode controllers) determines the output [pole and zero](https://en.wikipedia.org/wiki/Pole%E2%80%93zero_plot). In voltage mode converters, it forms a resonant circuit with the output inductor. In both cases, we must provide [loop compensation](http://www.linear.com/docs/46311) and that is partly determined by the value of the output capacitor(s).
(Note: I am aware that using ceramics on the output of a current mode device requires other techniques to provide an output zero as a ceramic capacitor zero is too high in frequency to be useful).
These capacitor(s) must be carefully [chosen](http://www.linear.com/docs/4165); changing these values requires re-assessing the loop compensation components, or it is quite possible loop instability can result.
This re-assessment may also reduce the loop bandwidth of the supply, reducing transient performance. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | From Andy akas comment:
If the supply you are using has [specific output capacitor requirements](http://www.ti.com/product/lm1117?keyMatch=lm1117&tisearch=Search-EN-Everything), then make sure you follow them. For all these types of regulator linked (LDO), there is usually a minimum capacitance only. (search the datasheet for ESR).
If you are using a switch-mode regulator, then the output capacitor (in current mode controllers) determines the output [pole and zero](https://en.wikipedia.org/wiki/Pole%E2%80%93zero_plot). In voltage mode converters, it forms a resonant circuit with the output inductor. In both cases, we must provide [loop compensation](http://www.linear.com/docs/46311) and that is partly determined by the value of the output capacitor(s).
(Note: I am aware that using ceramics on the output of a current mode device requires other techniques to provide an output zero as a ceramic capacitor zero is too high in frequency to be useful).
These capacitor(s) must be carefully [chosen](http://www.linear.com/docs/4165); changing these values requires re-assessing the loop compensation components, or it is quite possible loop instability can result.
This re-assessment may also reduce the loop bandwidth of the supply, reducing transient performance. | Larger capacitors also have more parasitics (eg equiv. series resistance and inductance.) This is what "slows them down" so to speak. |
224,421 | I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and then using a larger size or adding more until the scope shows acceptable (very low) levels of ripple and noise.
Besides the cost of the capacitors, is there any tradeoff to rounding up (a lot) and just using a very large capacitor(s) rather than trying to calibrate the sizing to "just enough" but not more than that? | 2016/03/24 | [
"https://electronics.stackexchange.com/questions/224421",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/103716/"
] | As far as caps go, there are two competing requirements:long-term (ripple) and instantaneous (spike). A big electrolytic can give you the former but not the latter. Generally you parallel your large electrolytic with a smaller 0.1uF capable of supplying that instantaneous spike whilst the electrolytic lumbers into action. Or the 0.1uF may be for local decoupling to stabilise that regulator. If the specified capacitor is actually 0.1uF or smaller, then the intention of the capacitor is to supply small amounts of charge very fast. Do not replace this with a bigger electrolytic - that's definitely a case where larger is worse not better.
Going past that, you'll have to tell us what kind of regulators you're dealing with. If it's just a basic linear regulator then it doesn't really matter. If you have a switching regulator though, the capacitor will affect the resonant frequency of the switcher, so be very careful there. | Note: my interpretation of the OPs post is we are talking about capacitors on the output of voltage regulators, some other posts seem to assume the asker is talking about capacitors on rectifiers.
The main downside of a bigger capacitor is that the switch on rise time and switch off fall time will be greater. That means more stress on the regulator during startup and in extreme cases may even cause an overcurrent shutdown of the regulator. It can also cause problems for loads which don't handle undervoltage very well.
Having said that I don't think there is any point trying to micromanage the size of such capacitors. In most cases allowing a generous margin (a factor of 2 or more) over what you think you need is unlikely to be a problem. |
6,103,467 | I'm using the Speech Recognizer Intent in Android. Is there a way to add your own customized words or phrases to Android's Speech recognition 'dictionary' | 2011/05/23 | [
"https://Stackoverflow.com/questions/6103467",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/517733/"
] | No. You can only use the two language models supported.
The built in speech recognition provided by google only supports the dictation and search language models. See <http://developer.android.com/reference/android/speech/RecognizerIntent.html> and LANGUAGE\_MODEL\_FREE\_FORM or LANGUAGE\_MODEL\_WEB\_SEARCH.
<http://developer.android.com/resources/articles/speech-input.html> says:
>
> You can make sure your users have the
> best experience possible by requesting
> the appropriate language model:
> free\_form for dictation, or web\_search
> for shorter, search-like phrases. We
> developed the "free form" model to
> improve dictation accuracy for the
> voice keyboard, while the "web search"
> model is used when users want to
> search by voice
>
>
> | Michael is correct, you cannot change the Language Model.
However, you can use "sounds like" algorithms to process the results from Android and match words it doesn't know.
See my answer here:
[speech recognition reduce possible search results](https://stackoverflow.com/questions/8778409/speech-recognition-reduce-possible-search-results/8779478#8779478) |
192,030 | I'm planning to backup a O365 site through PowerShell, but I couldn't find the command for it anywhere on the internet. | 2016/08/27 | [
"https://sharepoint.stackexchange.com/questions/192030",
"https://sharepoint.stackexchange.com",
"https://sharepoint.stackexchange.com/users/54632/"
] | There is no powershell command available for backup and restore in SharePoint Online(office 365).
For backup, you have to rely either to MSFT as they keep the backup for 14 days or you have to use the 3rd party tools to take the backup of your online sites.
<https://threewill.com/the-4-options-you-need-to-know-about-sharepoint-online-backup-and-restore/>
<http://www.metavistech.com/support/how-to/how-backup-and-restore-office-365-and-hosted-sharepoint-environments-using-metavis-ba> | As far as I know—and even after searching for your issue—there isn’t a command for this. There is a script that would help through:
<https://gallery.technet.microsoft.com/scriptcenter/PowerShell-Backup-Script-956f312c>
It is also on GitHub: <https://github.com/Seidlm/PowerShell-Backup-Script>
Still, for enterprises, it is safer to use a third-party solution. There are a bunch of options out there ([Altaro](https://www.altaro.com/), [Nakivo](https://www.nakivo.com/microsoft-office-365-backup/), [Druva](https://www.druva.com/), etc.). |
24,907 | I would be interested in creating a mesh (2D or 3D) to be used in a finite element solver. Does blender have a plugin that can do this? If not, how difficult would it be to write one myself?
What this plugin should be able to do is 1) partition a mesh into finite elements using some rule, 2) be able to label boundaries and different subdomains somehow and 3) export the mesh in some format that can be read by finite element solver I want to use (in my case, this would be FEniCS). | 2015/02/17 | [
"https://blender.stackexchange.com/questions/24907",
"https://blender.stackexchange.com",
"https://blender.stackexchange.com/users/11645/"
] | Well it is easy if you use existing librarys.
The greatest problem is generating a useful mesh for finite element analysis. In this case use the open source mesher "netgen" or "gmsh".
After generating the mesh there are several other openSource tools which can help you with subdomains and boundaries
----Fast manual solution ----
Export the blender file as an stl.
Then import it in netgen and create a tetrahedral mesh.
After that use FreeCAD or CalculiX for labeling boundaries
---- Automatic solution ----
Use FreeCAD for the automatic import of the blender files and call netgen or gmsh. | If you want to create a shell mesh with mainly quad elements then yes it is possible. Export the blender model in .stl format. Down load, install and run salome FE pre-post processor(IT IS FREE), run, create new session, go into mesh then import .stl as an FE mesh. It will be all triangles so go into : Modification; Union of triangles (NOT UNION OF TWO TRIANGLES) and select the 'minimum angle' option. Hey presto your triangle only mesh is 99.5% quads.
You can export as .dat for Nastran, .unv for Hypermesh or .med for Code Aster. If you have no experience of shell models then bear in mind that the elements should be grouped according to material, thickness and, in the case of Code Aster, loading. |
117,565 | I (with the help of an HVAC professional) installed a ductless, split system. It's a 24,000 BTU, single head system. What surprised me is how much energy (relative to everything else in the house) it uses while in the off/stand-by mode.
It's on a dedicated circuit, and I calculated using my Aeotec Home Energy Monitor that it's continuously using about 130 W with no visible operation. The head/air handler is "off", no noise from the compressor, compressor fan is not moving, etc.
Is this common for systems to use this much energy in stand-by or does it indicate something may be wrong with the wiring or connections?
Additional notes:
1. My system doesn't make an off/standby distinction. There is just an off button on the remote. I use the terms interchangeably b/c while it is "off" it is still drawing 130 W of power.
2. The home energy monitor uses clamps (one on each incoming 120V main line). I know it's ~ 130 W by monitoring the usage for 5 min, throwing the 2 pole breaker for the A/C, calculating the diff, and then turning it back on to verify. It appears to be fairly accurate for other circuits that I've tested (e.g. ~15 W for an LED lamp, < 1 W for an in-panel surge protector, ~60-70 W for the fridge, spikes +1000 W for the microwave, etc.)
[](https://i.stack.imgur.com/ZsWXB.png) | 2017/06/30 | [
"https://diy.stackexchange.com/questions/117565",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/3861/"
] | Your unit is probably a Heat Pump. I sell these and I'm not aware of any companies that still sell a/c only units since the cost difference was minimal they have been phased out. So being a heat pump it would have a crankcase heater either under or wrapped around the compressor. As long as the main power switch is on the heater will be energized whenever the compressor is off. That is to keep the oil in the system liquid so it can mix with the refrigerant gas when in operation. It is a resistance type heater so the wattage seems reasonable. | In general most equipment or appliances that have electronic controls will use some AC while the equipment is in the off position. You just mentioned you turn your unit on and off with a remote. So there must be power to sense the remote and its calls to start etc. Also the need for the consumer to want instant start for their equipment, manufacturer's design power circuits that remain continually warm so they get that response.
All that being said. We would really not know if the amount you measured is accurate, or is high or low by industry standards unless we had some sort of engineering data base that would give us that information. To get that you would probably have to be part of that type of manufacturer. |
117,565 | I (with the help of an HVAC professional) installed a ductless, split system. It's a 24,000 BTU, single head system. What surprised me is how much energy (relative to everything else in the house) it uses while in the off/stand-by mode.
It's on a dedicated circuit, and I calculated using my Aeotec Home Energy Monitor that it's continuously using about 130 W with no visible operation. The head/air handler is "off", no noise from the compressor, compressor fan is not moving, etc.
Is this common for systems to use this much energy in stand-by or does it indicate something may be wrong with the wiring or connections?
Additional notes:
1. My system doesn't make an off/standby distinction. There is just an off button on the remote. I use the terms interchangeably b/c while it is "off" it is still drawing 130 W of power.
2. The home energy monitor uses clamps (one on each incoming 120V main line). I know it's ~ 130 W by monitoring the usage for 5 min, throwing the 2 pole breaker for the A/C, calculating the diff, and then turning it back on to verify. It appears to be fairly accurate for other circuits that I've tested (e.g. ~15 W for an LED lamp, < 1 W for an in-panel surge protector, ~60-70 W for the fridge, spikes +1000 W for the microwave, etc.)
[](https://i.stack.imgur.com/ZsWXB.png) | 2017/06/30 | [
"https://diy.stackexchange.com/questions/117565",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/3861/"
] | I have a building with a Fujitsu heat pump that is not used in the summer so I turned off the breaker for the unit and everything else in the building was off. I monitored usage on the supplier web site and had "0" usage for 2 months. A week ago I noticed that the site was showing between 4kw and 6kw usage each day. When I checked, someone had turned on the heat pump breaker by mistake. So, the heat pump was consuming $18 to $28 in electricity per month when turned off at the remote! | In general most equipment or appliances that have electronic controls will use some AC while the equipment is in the off position. You just mentioned you turn your unit on and off with a remote. So there must be power to sense the remote and its calls to start etc. Also the need for the consumer to want instant start for their equipment, manufacturer's design power circuits that remain continually warm so they get that response.
All that being said. We would really not know if the amount you measured is accurate, or is high or low by industry standards unless we had some sort of engineering data base that would give us that information. To get that you would probably have to be part of that type of manufacturer. |
117,565 | I (with the help of an HVAC professional) installed a ductless, split system. It's a 24,000 BTU, single head system. What surprised me is how much energy (relative to everything else in the house) it uses while in the off/stand-by mode.
It's on a dedicated circuit, and I calculated using my Aeotec Home Energy Monitor that it's continuously using about 130 W with no visible operation. The head/air handler is "off", no noise from the compressor, compressor fan is not moving, etc.
Is this common for systems to use this much energy in stand-by or does it indicate something may be wrong with the wiring or connections?
Additional notes:
1. My system doesn't make an off/standby distinction. There is just an off button on the remote. I use the terms interchangeably b/c while it is "off" it is still drawing 130 W of power.
2. The home energy monitor uses clamps (one on each incoming 120V main line). I know it's ~ 130 W by monitoring the usage for 5 min, throwing the 2 pole breaker for the A/C, calculating the diff, and then turning it back on to verify. It appears to be fairly accurate for other circuits that I've tested (e.g. ~15 W for an LED lamp, < 1 W for an in-panel surge protector, ~60-70 W for the fridge, spikes +1000 W for the microwave, etc.)
[](https://i.stack.imgur.com/ZsWXB.png) | 2017/06/30 | [
"https://diy.stackexchange.com/questions/117565",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/3861/"
] | My Mitsubishi mini splits use .75 kwh each when "off". When you are only allotted 22 kw per day, they severely eat in to my allotment.
I have to turn the breakers completely off, or I go over my "allowed" consumption. | In general most equipment or appliances that have electronic controls will use some AC while the equipment is in the off position. You just mentioned you turn your unit on and off with a remote. So there must be power to sense the remote and its calls to start etc. Also the need for the consumer to want instant start for their equipment, manufacturer's design power circuits that remain continually warm so they get that response.
All that being said. We would really not know if the amount you measured is accurate, or is high or low by industry standards unless we had some sort of engineering data base that would give us that information. To get that you would probably have to be part of that type of manufacturer. |
117,565 | I (with the help of an HVAC professional) installed a ductless, split system. It's a 24,000 BTU, single head system. What surprised me is how much energy (relative to everything else in the house) it uses while in the off/stand-by mode.
It's on a dedicated circuit, and I calculated using my Aeotec Home Energy Monitor that it's continuously using about 130 W with no visible operation. The head/air handler is "off", no noise from the compressor, compressor fan is not moving, etc.
Is this common for systems to use this much energy in stand-by or does it indicate something may be wrong with the wiring or connections?
Additional notes:
1. My system doesn't make an off/standby distinction. There is just an off button on the remote. I use the terms interchangeably b/c while it is "off" it is still drawing 130 W of power.
2. The home energy monitor uses clamps (one on each incoming 120V main line). I know it's ~ 130 W by monitoring the usage for 5 min, throwing the 2 pole breaker for the A/C, calculating the diff, and then turning it back on to verify. It appears to be fairly accurate for other circuits that I've tested (e.g. ~15 W for an LED lamp, < 1 W for an in-panel surge protector, ~60-70 W for the fridge, spikes +1000 W for the microwave, etc.)
[](https://i.stack.imgur.com/ZsWXB.png) | 2017/06/30 | [
"https://diy.stackexchange.com/questions/117565",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/3861/"
] | Your unit is probably a Heat Pump. I sell these and I'm not aware of any companies that still sell a/c only units since the cost difference was minimal they have been phased out. So being a heat pump it would have a crankcase heater either under or wrapped around the compressor. As long as the main power switch is on the heater will be energized whenever the compressor is off. That is to keep the oil in the system liquid so it can mix with the refrigerant gas when in operation. It is a resistance type heater so the wattage seems reasonable. | I have a building with a Fujitsu heat pump that is not used in the summer so I turned off the breaker for the unit and everything else in the building was off. I monitored usage on the supplier web site and had "0" usage for 2 months. A week ago I noticed that the site was showing between 4kw and 6kw usage each day. When I checked, someone had turned on the heat pump breaker by mistake. So, the heat pump was consuming $18 to $28 in electricity per month when turned off at the remote! |
117,565 | I (with the help of an HVAC professional) installed a ductless, split system. It's a 24,000 BTU, single head system. What surprised me is how much energy (relative to everything else in the house) it uses while in the off/stand-by mode.
It's on a dedicated circuit, and I calculated using my Aeotec Home Energy Monitor that it's continuously using about 130 W with no visible operation. The head/air handler is "off", no noise from the compressor, compressor fan is not moving, etc.
Is this common for systems to use this much energy in stand-by or does it indicate something may be wrong with the wiring or connections?
Additional notes:
1. My system doesn't make an off/standby distinction. There is just an off button on the remote. I use the terms interchangeably b/c while it is "off" it is still drawing 130 W of power.
2. The home energy monitor uses clamps (one on each incoming 120V main line). I know it's ~ 130 W by monitoring the usage for 5 min, throwing the 2 pole breaker for the A/C, calculating the diff, and then turning it back on to verify. It appears to be fairly accurate for other circuits that I've tested (e.g. ~15 W for an LED lamp, < 1 W for an in-panel surge protector, ~60-70 W for the fridge, spikes +1000 W for the microwave, etc.)
[](https://i.stack.imgur.com/ZsWXB.png) | 2017/06/30 | [
"https://diy.stackexchange.com/questions/117565",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/3861/"
] | Your unit is probably a Heat Pump. I sell these and I'm not aware of any companies that still sell a/c only units since the cost difference was minimal they have been phased out. So being a heat pump it would have a crankcase heater either under or wrapped around the compressor. As long as the main power switch is on the heater will be energized whenever the compressor is off. That is to keep the oil in the system liquid so it can mix with the refrigerant gas when in operation. It is a resistance type heater so the wattage seems reasonable. | My Mitsubishi mini splits use .75 kwh each when "off". When you are only allotted 22 kw per day, they severely eat in to my allotment.
I have to turn the breakers completely off, or I go over my "allowed" consumption. |
23,338 | I am currently watching the Rapid World Championship and the amount of draws between players is absolutely shocking. I'm not talking about games where each player fights to the end and the game just happens to be a draw - that is perfectly okay in my opinion.
But so many games are being drawn on default - players are simply agreeing to draw far before any sort of endgame is reached. Just now, 5 minutes ago, Anish Giri drew a game after **10 moves**. 10!!! TEEEEN!!!
Why do chess tournaments allow this scandalous behavior?
Imagine if any other sport was played this way. Imagine if Barcelona and Real Madrid are playing football, and they just decide to leave the pitch after 20 minutes because they no longer want to play, and agree to a draw.
Why is this behavior not banned? Why isn't a rule enforced so that a draw can only be reached after many moves (as was the case in the World Championship with Caruana and Carlsen)? | 2018/12/28 | [
"https://chess.stackexchange.com/questions/23338",
"https://chess.stackexchange.com",
"https://chess.stackexchange.com/users/18166/"
] | Anish Giri was likely playing a "solved" opening, one in which all lines have been analyzed to a draw. Also, Giri is **extremely** hard to beat and draws many of his games (his weakness is that he doesn't often win). In this situation, there was likely no room for progress outside of severe blunders, so it's almost a respect issue, where Giri and his opponent respected each other enough to admit that no blunders were likely to be made, especially in this line. This sort of "guaranteed ending" does not occur in games like football or baseball or whatever. | Many FIDE tournaments do have a rule where a draw can only be reached after >= 30 moves. If I recall correctly, this rule is quite predominant especially in the closed tournaments which super GMs play in.
I suppose they could also implement the rule in rapid and blitz tournaments, but these events are more informal and less important. The need for so many extra strict rules decreases.
Sports like hockey, football, etc don't allow quick draws since the game could never naturally end early on in a draw. In chess though, the game could easily end (naturally) in a draw. |
272,747 | I was walking around like a fool in the park and I was basically going around for 2 hours looking at my screen. Does the game give a notification when you see a Pokemon close enough to tab it or do I have to glue my eyes to my cellphone? | 2016/07/07 | [
"https://gaming.stackexchange.com/questions/272747",
"https://gaming.stackexchange.com",
"https://gaming.stackexchange.com/users/153371/"
] | Personal experience:
The screen needs to be on and Pokemon Go needs to be active.
It will vibrate when a Pokemon is near.
When you get the accessory called [Pokemon Go Plus](http://rads.stackoverflow.com/amzn/click/B01H482N6E) it will notify when Pokemon are near even when the screen is not active.
Pokemon Go has a power save mode, when you turn it on it can be turned up side down in your pocket, the screen will go blackish with the Pokemon Go logo on it, it will vibrate if a Pokemon is near | In order to receive notifications about nearby Pokemon and have steps tracked for egg counting, you must have the screen on and the app in the foreground.
You may use Battery Saver Mode to darken your screen and avoid looking at your phone. When the phone is turned upside-down (in your pocket, for example), the screen will darken but the app will continue running in the foreground. |
9,116,567 | After researching ways to make a secure log in form with 'remember me' functionality I've come across many conflicting views on how to make this secure. The log in system I wish to create does not need to be highly secure, but I'd like to pick a nice secure and easy method and I have two questions.
1. What should be stored in the session variables to check a user is logged in, is this just username (or ID). If it is just the username, what happens in the case where a user finds their account has been compromised and wishes to change the password to stop the malicious user messing around with their account? If the malicious user has a session then even if the password is changed they can continued being malicious until their session expires, can this be avoided - maybe invalidate all sessions with that username on password change?
2. Is storing a password (re-encrypted with a salt used just for cookies) and username in a (HttpOnly) cookie a decent enough way of having the 'remember me' functionality? I've heard ways where a database stores a username and a randomly generated key, and this is also put in the user cookie. Then when a user action occurs the old key is replaced with a new one and given to the user's cookie. Is this type of cookie security worth it or will the usual re-encrypted password method be sufficient? | 2012/02/02 | [
"https://Stackoverflow.com/questions/9116567",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1130734/"
] | Usually if you want to remember the user, you generate a "key" and store it in the database, then set its "lifetime" (this can be anything, like 6 hours or 2 days). You store that key in the cookie (along with the userid). Now, every time the user connects to the website you compare both keys. If the key in the database has exceeded its lifetime, you generate a new key and store it in the cookie. Thus, if someone steals the cookie (somehow) he would have to use it before you connect to the website again and reset the key. This is a method I most commonly see. | 1. If the account has already been compromised, there's little, if anything, that you can do. The malicious user will likely change the account password him/herself, along with the email address, etc. Trying to account for the case where the "real" user and a malicious user are logged in at the same time is pointless, IMO.
2. Never store any sensitive data in a cookie (HTTP-only or not). |
4,413,893 | I'm to make a firefox extension which will inject some js code as well as whole jQuery lib.
I want it to happen (the injection) when user pushes the button placed somewhere in the browser. I have read docs form MDC and other tutorials about making the extensions and they seem complicated to me. Technologies such as XPCOM or XUL are completely useles form me (I have no time to learn them in fact). My question is, is it another way of solving my problem then following MDC? I need to find quicker way of doing my task.
I've already written the extension for Google Chrome, and it was a way simplier than doing it for Firefox. | 2010/12/10 | [
"https://Stackoverflow.com/questions/4413893",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/538465/"
] | I would take a look at [Greasemonkey](http://www.greasespot.net/). It shares some similarity with Chrome plugins in function (Script gets injected on the page, local storage, etc). As for using JQuery with Greasemonkey, look at this question: [How can I use jQuery in Greasemonkey?](https://stackoverflow.com/questions/859024/how-can-i-use-jquery-in-greasemonkey) | You can use a [bookmarklet to add jQuery](http://www.learningjquery.com/2009/04/better-stronger-safer-jquerify-bookmarklet/) to a page and/or inject any other code. |
38,395,045 | For Christmas 2016, me and my dad want to do a Lightshow for our neighborhood with lights and **music**.
[](https://i.stack.imgur.com/s86mw.jpg)
We have the lights set up, but the music is a problem. We don't want to put huge speakers in our garden because that would be very annoying for our densely populated neighborhood.
So, we came up with this concept:
[](https://i.stack.imgur.com/eXwQa.jpg)
The computer (Windows 7) handles the lights with a sequencer from Light-o-rama.
**Now my question is:**
How can I stream audio from the PC to the smartphones?
I can figure out the smartphone end myself, but the streaming audio from PC is the thing here.
The solution can be anything! But I can't seem to figure it out!
Relevant languages I can do are:
1. C++
2. C#
3. Java
4. NodeJS
5. ASP.NET
But it can also be a program that already can do this!
EDIT:
**THIS IS A MUST: Lights and music have to stay in sync! The lights dance to the music**
Anything helps! Thx in advance!
EDIT:
I have awarded the in my eyes most fitting solution to this case the bounty, however, I haven't had the time to test all of the posted solutions. I will try to try every single one of them and then select that answer as the solution! Please see my comment underneath the answer which has the bounty! Thx all for the help! | 2016/07/15 | [
"https://Stackoverflow.com/questions/38395045",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/3975501/"
] | I have a complete solution stack for you:
* You should use an [OpenWRT](https://wiki.openwrt.org/doc/howto/wireless.hotspot.wifidog) router to build a [captive portal](https://en.wikipedia.org/wiki/WiFiDog_Captive_Portal) (all http could be redirected to your url -> your audio streaming pc)
* A [VLC](http://www.videolan.org/vlc/) is able to [stream](https://www.youtube.com/watch?v=GK2EW9j7D20) your content as you want. If you want you could start the stream from [command line](https://wiki.videolan.org/Documentation:Streaming_HowTo/Command_Line_Examples/).
In my experience this kind of VLC stream is the most effective one, it has almost 0 delay compared to other solutions (I tried gstreamer). If you really would like to stick with **Java** you are able to use [**VLCJ**](https://github.com/caprica/vlcj) which is a nice solution too.
**Extra**: also with VLC you could set up a camera in front of your house to show that in your stream too! | It seems that the dev has already been done, there is an app "Speakerfy" that looks promising.
It is available on most of the mobile platforms and seems to do exactly what you need.
There is an article on this app at the following link that should give even more info.
<http://techland.time.com/2013/04/01/speakerfy-a-free-app-for-whole-home-audio-or-silent-discos/>
I hope this helps. |
38,395,045 | For Christmas 2016, me and my dad want to do a Lightshow for our neighborhood with lights and **music**.
[](https://i.stack.imgur.com/s86mw.jpg)
We have the lights set up, but the music is a problem. We don't want to put huge speakers in our garden because that would be very annoying for our densely populated neighborhood.
So, we came up with this concept:
[](https://i.stack.imgur.com/eXwQa.jpg)
The computer (Windows 7) handles the lights with a sequencer from Light-o-rama.
**Now my question is:**
How can I stream audio from the PC to the smartphones?
I can figure out the smartphone end myself, but the streaming audio from PC is the thing here.
The solution can be anything! But I can't seem to figure it out!
Relevant languages I can do are:
1. C++
2. C#
3. Java
4. NodeJS
5. ASP.NET
But it can also be a program that already can do this!
EDIT:
**THIS IS A MUST: Lights and music have to stay in sync! The lights dance to the music**
Anything helps! Thx in advance!
EDIT:
I have awarded the in my eyes most fitting solution to this case the bounty, however, I haven't had the time to test all of the posted solutions. I will try to try every single one of them and then select that answer as the solution! Please see my comment underneath the answer which has the bounty! Thx all for the help! | 2016/07/15 | [
"https://Stackoverflow.com/questions/38395045",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/3975501/"
] | If you can get everyone to download this app: [SoundWire](https://play.google.com/store/apps/details?id=com.georgie.SoundWireFree&hl=en) you can stream audio from Windows to any Android phone (assuming your friends are cool)
Check it out looks pretty cool, you can even stream a youtube video and get the audio synced up with any android smartphone | It seems that the dev has already been done, there is an app "Speakerfy" that looks promising.
It is available on most of the mobile platforms and seems to do exactly what you need.
There is an article on this app at the following link that should give even more info.
<http://techland.time.com/2013/04/01/speakerfy-a-free-app-for-whole-home-audio-or-silent-discos/>
I hope this helps. |
38,395,045 | For Christmas 2016, me and my dad want to do a Lightshow for our neighborhood with lights and **music**.
[](https://i.stack.imgur.com/s86mw.jpg)
We have the lights set up, but the music is a problem. We don't want to put huge speakers in our garden because that would be very annoying for our densely populated neighborhood.
So, we came up with this concept:
[](https://i.stack.imgur.com/eXwQa.jpg)
The computer (Windows 7) handles the lights with a sequencer from Light-o-rama.
**Now my question is:**
How can I stream audio from the PC to the smartphones?
I can figure out the smartphone end myself, but the streaming audio from PC is the thing here.
The solution can be anything! But I can't seem to figure it out!
Relevant languages I can do are:
1. C++
2. C#
3. Java
4. NodeJS
5. ASP.NET
But it can also be a program that already can do this!
EDIT:
**THIS IS A MUST: Lights and music have to stay in sync! The lights dance to the music**
Anything helps! Thx in advance!
EDIT:
I have awarded the in my eyes most fitting solution to this case the bounty, however, I haven't had the time to test all of the posted solutions. I will try to try every single one of them and then select that answer as the solution! Please see my comment underneath the answer which has the bounty! Thx all for the help! | 2016/07/15 | [
"https://Stackoverflow.com/questions/38395045",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/3975501/"
] | Your diagram suggests that each device would be on your local WiFi, which means the guests would need to join your network. That means they would need to know the SSID, there would be no need for a passphrase as you would need to publicly post the SSID and passphrase. Then, unless you have created some DMZ for this musical network, anyone would have access to your network.
But the bigger issue is the act of streaming itself as there is device buffering with such things. It would be near impossible to have the music sync'ed on the devices to any light display.
The best solution would be to broadcast over radio wave on an open channel. Here are some starting points for that:
<http://www.jpole-antenna.com/2013/10/11/broadcast-high-quality-music-for-your-holiday-lights-display/>
<https://sourcefmtransmitter.com/shop/category/christmas-lights-to-music/>
* Good Luck! | It seems that the dev has already been done, there is an app "Speakerfy" that looks promising.
It is available on most of the mobile platforms and seems to do exactly what you need.
There is an article on this app at the following link that should give even more info.
<http://techland.time.com/2013/04/01/speakerfy-a-free-app-for-whole-home-audio-or-silent-discos/>
I hope this helps. |
6,973,561 | i've got a few old mobos and i was wondering whether it might be possible to create a pair of pci header cards with interconnect wires and write some software to drive the interconnect cards to allow one of the mobos to access the cpu and ram on the other? i'm sure it would be an arduous undertaking involving writing a device driver for the header boards and then writing an application to make use of the interconnect; perhaps a simple demo demonstrating a thread running on each processor and use of both sets of ram, perhaps creating a mini virtual machine that maps 2x3gb ram on 32 bit mobos to a single 6 gb address space. a microcontroller may be needed on each pci header card to act as a translator.
given that mobos almost always have multiple pci slots, i wonder if these interconnected card pairs could be used to daisychain mobos in a sort of high speed beowulf cluster.
i would use debian for each mobo and probably just an atmega128 for each card with a couple of ribbon cables for interconnecting.
pci is basically just an io bus, so i don't see why this shouldn't be possible (but it would be pretty hard going).
does anyone have any advice or has this sort of thing been done before?
### Update:
Thanks Martin. What you say makes sense, and it would also seem that if it were possible that it would have already been done before.
Instead, would it be possible to indirectly control the slave cpu by booting it using a "pretend" bootable storage device (hard disk, usb stick, etc)? As long as the slave mobo thinks its being operated by an operating system on a real device it should work.
This could potentially extend to any interface (sata, ide, usb etc); if you connected two pcs together with a sata/ide/usb cable (plug one end of an ide ribbon into one mobo and the other into another mobo), that would be all the hardware you need. the key is in creating a new driver for that interface on the master pc, so instead of the master pc treating that interface as having a storage device on it, it would be driven as a dummy bootable hard disk for the slave computer. this would still be a pretty difficult job for me because i've never done device drivers before, but at least i wouldn't need a soldering iron (which would be much further beyond me). i might be able to take an open source ide driver for linux, study it, and then butcher it to create something that kindof acts in reverse (instead of getting data off it, an application puts data onto it for the slave machine to access like a hard disk). i could then take a basic linux kernel and try booting the slave computer from an application on the master computer (via the butchered master pc ide/sata/usb device driver). for safety, i would probably try to isolate my customised driver as much as possible by targeting an interface not being used for anything else on the master pc (the master pc might use all sata hard disks with the ide bus normally unused, so if i created a custom ide driver it might cause less problems with the host system - because it is sata driven).
Does anyone know if anything like this (faking a bootable hard disk from another pc) has ever been tried before? It would make a pretty cool hackaday on youtube, but also seriously it could add a new dimension to parallel computing if it proved promising. | 2011/08/07 | [
"https://Stackoverflow.com/questions/6973561",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/882844/"
] | Is there any reason you cannot use a [DataGroup](http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/spark/components/DataGroup.html) wrapper around a [Scroller](http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/spark/components/Scroller.html) with a [TileLayout](http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/spark/layouts/TileLayout.html) and use the [IconItemRenderer](http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/spark/components/IconItemRenderer.html)? | I'm not that familiar with the mobile version of Flex, but in ordinary Flex this is just a matter of defining a renderrer class for your List control and use a clickable image (or some Image Button class) as the renderrer. |
2,565,059 | I'm think something like Facebook apps here. User generated pieces of code that people can write to interact with my app.
I understand how an authenticated API works, but this seems a little more complicated because not only does the APP have to authenticate itself (with a regular api-key) but the USER using the app has to be authenticated somehow too, without giving the app free reign.
I've been reading a bit here to see how FB does it: <http://wiki.developers.facebook.com/index.php/How_Facebook_Authenticates_Your_Application>
And it looks like you have to pass a signature in addition to the api-key along with every call, but I'm having trouble wrapping my head around how this gets generated and used on the other end (my server).
Figure there must be a simple explanation of this out there? Thanks!
P.S. I'm building a Rails app if there are any applicable gems/plugins. | 2010/04/02 | [
"https://Stackoverflow.com/questions/2565059",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/76486/"
] | Sure, start up Firebug while using any page that has jquery loaded and type commands into the console. Am I missing something? | I was googling for irb and jquery. Much better would have been injecting jquery firebug.
Found this
<http://www.learningjquery.com/2006/12/jquerify-bookmarklet>
and it answers my question. If any one has any other tips please share. |
11,105 | I would like to have a comparison between the privacy and scalability features of Monero vs Beam. I have heard some people say that these are privacy-oriented coins, and I would like to learn more. | 2019/04/13 | [
"https://monero.stackexchange.com/questions/11105",
"https://monero.stackexchange.com",
"https://monero.stackexchange.com/users/42/"
] | Beam authored a similar piece on a comparison between Beam, Monero, and Zcash that I recommend you read [here](https://medium.com/beam-mw/whats-the-difference-between-monero-zcash-and-beam-953eafd89354) to get a different perspective. I personally disagree with some points, but the high-level details are more or less correct.
Pardon the image, but there is no way to create tables in StackExchange.
[](https://i.stack.imgur.com/EdORQ.png)
Beam's privacy is best characterized as "Monero with aggressive pruning and no ring signatures." Users who are unable to get access to old information cannot pull up past transaction information by looking at the current ledger state. However, those who receive transactions as they are broadcast can see the inputs and outputs for individual transactions. This effectively indicates whether outputs are spent, something that is not possible with Monero. I argue that the article overstates the privacy protections of "confidential transactions" in Beam. CT is a technology that hides transaction amounts, nothing else. The output transaction graph is hidden through obscurity of information, not anything committed on-chain.
Monero's scalability has improved significantly over recent years. Transaction sizes fell from ~13 kB to ~1.5kB. [Monero now supports pruning](https://getmonero.org/2019/02/01/pruning.html), allowing users to ignore most of the information for old transactions. Still, Beam allows more information to be pruned, and they prune it much faster.
I did not include network privacy on this chart, since both Monero and Beam provide network privacy. Monero provides support for Tor and i2p, and it later will provide support for Dandelion++. Beam supports Dandelion++, and users can use Tor or i2p if they configure it manually. Transaction network obfuscation is important, but it's less important for most people than graph protection.
I like to think of Monero and Beam as projects that are pushing the privacy and scalability boundaries, each beginning in different positions. Monero is focused on a privacy angle with scalability second, whereas Beam has the opposite focus.
[](https://i.stack.imgur.com/t6dz9.png) | Beam is providing **better** privacy and **much better** scalability and IBD time than Monero. During the Dandelion stem phase, before the TXs are broadcasted to the P2P layer, they are being CoinJoined together. This is done by both Grin and Beam. Beam novel addition is the use of Decoy Outputs (Dummy Zero Outputs) which are being added when needed. Those decoys look like any other output in the system and they are totally indistinguishable from other outputs (unlike Monero decoys). They are later being spent at a random block height, so no permanent clutter on the blockchain. This mechanism is very effective in breaking linkability. Beam and Grin are using FlyClient tech to allow extremely fast trust-less sync with the network. It shows on the mobile clients which are unmatched in the space in terms of fast sync without the need for a server size.
Resources:
* [Bitcoin Q&A: MimbleWimble and Dandelion](https://www.youtube.com/watch?v=LjDJGTpK_lE)
* [Grin Privacy Primer](https://github.com/mimblewimble/docs/wiki/Grin-Privacy-Primer)
* [Beam's Transaction graph obfuscation](https://github.com/BeamMW/beam/wiki/Transaction-graph-obfuscation)
* [Flyclient: Super-Light Clients for Cryptocurrencies](https://eprint.iacr.org/2019/226)
* Look at Fast Sync vs Full Sync (2nd graph from the end) to understand Mimblewimble huge advantage in scalability. IBD for a full node is extremely fast. [Beam Community Block Explorer](https://explorer.beamprivacy.community/)
* Download mobile clients and see FlyClient advantage [Beam Downloads page](https://www.beam.mw/downloads) |
140,476 | Context
-------
An evil wizard has used [*True Polymorph*](https://www.dndbeyond.com/spells/true-polymorph) to make one of their minions resemble the king. As a precaution against diviners, the wizard also casts [*Nystul/Arcanist's Magic Aura*](https://www.dndbeyond.com/spells/arcanists-magic-aura), "Mask", for 30 days, which will have the following effect until dispelled:
>
> You change the way the target appears to spells and magical effects that detect creature types, such as a paladin’s Divine Sense or the trigger of a *symbol* spell. You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.
>
>
>
The evil wizard then kills the true king and installs their polymorphed pawn on the thrown.
Later, a group of adventurers are trying to find the king at a masquerade party. They know the king is in attendance, but cannot find him due to the festive masks, so they cast [*Locate Creature*](https://www.dndbeyond.com/spells/locate-creature), naming the king as the spell's target. The description for this spell states the following:
>
> If the creature you described or named is in a different form, such as being under the effects of a *polymorph* spell, this spell doesn't locate the creature.
>
>
>
Question
--------
Does the *Locate Creature* spell fail, potentially revealing to the adventurers that the imposter attending the party is not truly the king? Or does *Nystal's Magic Aura* cause *Locate Creature* to function normally? | 2019/02/05 | [
"https://rpg.stackexchange.com/questions/140476",
"https://rpg.stackexchange.com",
"https://rpg.stackexchange.com/users/44303/"
] | The wording of the spell matters
--------------------------------
If the characters are aware that there might be an impostor and they word the spell carefully, then the spell will fail. For example "Show me Sir Galahad the Great, rightful King of Brittax, Friend of Elves." The polymorphed minion is not this specific person and the spell will fail.
However if they simply state, "Show me the king of Brittax," you have more leeway in adjudicating the results. In this case the rightful king is dead and the polymorphed minion *is* the king of Brittax and so the spell will very likely indicate the polymorphed minion. Of course the *Locate Creature* spell does indicate (PHB 256):
>
> If the creature you described or named is in a different form, such as being under the effects of a polymorph spell, this spell doesn’t locate the creature.
>
>
>
Is this relevant in this case? I would say no, because the creature is the king *because* of the polymorph spell. They are not in a ***different form*** (than what was asked for) because of the polymorph spell, they are in the ***desired form*** because of the polymorph spell. They are only the king *because of* the polymorph spell.
Lastly, if they say something like, "Show me the rightful king of Brittax," they may be guided towards a third NPC who would be the heir to the throne if it was known that the rightful king was dead.
Is the target *familiar* and *known to* the caster?
---------------------------------------------------
It's important to consider the limitations the spell places on who you can specifically locate. The spell description states:
>
> Describe or name a creature that is familiar to you.
>
>
> and
>
>
> The spell can locate a specific creature known to you, or the nearest creature of a specific kind (such as a human or a unicorn), so long as you have seen such a creature up close — within 30 feet — at least once.
>
>
>
This text is not overly clear, but it does suggest that if you've seen a specific creature within 30 feet they are known to you and the spell will work (barring other limitations). ***Familiar to you*** can mean a lot of things: It could mean you know of the person, or it could mean you are personally acquainted with them, or as the text suggests it could mean you have seen them once. As a GM, be sure to consider and interpret these statements when you resolve the effects of the spell. In the context of the party you describe it is very likely the PC has seen the potential targets of the spell. Also they may have met at other times in the campaign, or may just be known to the PC.
If I were the GM I would casually ask the spellcaster who they are targeting with the spell and apply the wording they use in-game to rule how the spell functions. As long as they are familiar with the target then the spell can locate that character.
In short
Yes the spell could fail, *and* you can play with the results depending on how the spellcaster PC words the spell and their familiarity with the target
-------------------------------------------------------------------------------------------------------------------------------------------------------
In regards to Nystal's Magic Aura, this spell would not affect *Locate Creature* in this case because the PC is attempting to locate a specific person, not a *type of creature*. NMA description states (PH 263):
>
> You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.
>
>
>
When *Locate Creature* is used to locate a single creature it is out of the scope of Nystal's Magic Aura because you are not looking for a *type* of creature. | >
> Does the Locate Creature spell fail, potentially revealing to the adventurers that the imposter attending the party is not truly the king?
>
>
>
Yes
>
> Or does Nystal's Magic Aura cause Locate Creature to function normally?
>
>
>
No
There is no conflict here - each spell does exactly what it says it does. The target of the *Locate Object* is the (dead) king. The imposter is not being targeted so *Nystul's Magic Aura* has no work to do.
Oh well - "the best laid schemes o' mice an' men Gang aft a-gley" |
140,476 | Context
-------
An evil wizard has used [*True Polymorph*](https://www.dndbeyond.com/spells/true-polymorph) to make one of their minions resemble the king. As a precaution against diviners, the wizard also casts [*Nystul/Arcanist's Magic Aura*](https://www.dndbeyond.com/spells/arcanists-magic-aura), "Mask", for 30 days, which will have the following effect until dispelled:
>
> You change the way the target appears to spells and magical effects that detect creature types, such as a paladin’s Divine Sense or the trigger of a *symbol* spell. You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.
>
>
>
The evil wizard then kills the true king and installs their polymorphed pawn on the thrown.
Later, a group of adventurers are trying to find the king at a masquerade party. They know the king is in attendance, but cannot find him due to the festive masks, so they cast [*Locate Creature*](https://www.dndbeyond.com/spells/locate-creature), naming the king as the spell's target. The description for this spell states the following:
>
> If the creature you described or named is in a different form, such as being under the effects of a *polymorph* spell, this spell doesn't locate the creature.
>
>
>
Question
--------
Does the *Locate Creature* spell fail, potentially revealing to the adventurers that the imposter attending the party is not truly the king? Or does *Nystal's Magic Aura* cause *Locate Creature* to function normally? | 2019/02/05 | [
"https://rpg.stackexchange.com/questions/140476",
"https://rpg.stackexchange.com",
"https://rpg.stackexchange.com/users/44303/"
] | Yes, but the spell fails for another reason
===========================================
*Nystal's Magic Aura* (MASK) states:
>
> You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.
>
>
>
The Mask is only changing the detected type or alignment of a creature. However, this isn't what *Locate Creature* is looking for:
>
> The spell can locate a specific creature known to you, or the nearest creature of a specific kind (such as a human or a unicorn), so long as you have seen such a creature up close--within 30 feet--at least once. If the creature you described or named is in a different form, such as being under the effects of a polymorph spell, this spell doesn't locate the creature.
>
>
>
As long as you *know* the True King, you can try and locate him. However, if you have not seen the True King, then he would not be a valid target for this as you don't actually know that there is a True King vs the False King.
For the sake of this question, let's say that the party *did* see the True King up close at one point and they attempt to *Locate* him at this party. If so, then *Nystal's Magic Aura* will do nothing to prevent the spell from working because it's only affecting knowing the False King's Type (humanoid?) or alignment via the Mask feature. In this case, the *Locate Creature* would not provide a direction unless the True King is within 1000' of the party. | >
> Does the Locate Creature spell fail, potentially revealing to the adventurers that the imposter attending the party is not truly the king?
>
>
>
Yes
>
> Or does Nystal's Magic Aura cause Locate Creature to function normally?
>
>
>
No
There is no conflict here - each spell does exactly what it says it does. The target of the *Locate Object* is the (dead) king. The imposter is not being targeted so *Nystul's Magic Aura* has no work to do.
Oh well - "the best laid schemes o' mice an' men Gang aft a-gley" |
140,476 | Context
-------
An evil wizard has used [*True Polymorph*](https://www.dndbeyond.com/spells/true-polymorph) to make one of their minions resemble the king. As a precaution against diviners, the wizard also casts [*Nystul/Arcanist's Magic Aura*](https://www.dndbeyond.com/spells/arcanists-magic-aura), "Mask", for 30 days, which will have the following effect until dispelled:
>
> You change the way the target appears to spells and magical effects that detect creature types, such as a paladin’s Divine Sense or the trigger of a *symbol* spell. You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.
>
>
>
The evil wizard then kills the true king and installs their polymorphed pawn on the thrown.
Later, a group of adventurers are trying to find the king at a masquerade party. They know the king is in attendance, but cannot find him due to the festive masks, so they cast [*Locate Creature*](https://www.dndbeyond.com/spells/locate-creature), naming the king as the spell's target. The description for this spell states the following:
>
> If the creature you described or named is in a different form, such as being under the effects of a *polymorph* spell, this spell doesn't locate the creature.
>
>
>
Question
--------
Does the *Locate Creature* spell fail, potentially revealing to the adventurers that the imposter attending the party is not truly the king? Or does *Nystal's Magic Aura* cause *Locate Creature* to function normally? | 2019/02/05 | [
"https://rpg.stackexchange.com/questions/140476",
"https://rpg.stackexchange.com",
"https://rpg.stackexchange.com/users/44303/"
] | The wording of the spell matters
--------------------------------
If the characters are aware that there might be an impostor and they word the spell carefully, then the spell will fail. For example "Show me Sir Galahad the Great, rightful King of Brittax, Friend of Elves." The polymorphed minion is not this specific person and the spell will fail.
However if they simply state, "Show me the king of Brittax," you have more leeway in adjudicating the results. In this case the rightful king is dead and the polymorphed minion *is* the king of Brittax and so the spell will very likely indicate the polymorphed minion. Of course the *Locate Creature* spell does indicate (PHB 256):
>
> If the creature you described or named is in a different form, such as being under the effects of a polymorph spell, this spell doesn’t locate the creature.
>
>
>
Is this relevant in this case? I would say no, because the creature is the king *because* of the polymorph spell. They are not in a ***different form*** (than what was asked for) because of the polymorph spell, they are in the ***desired form*** because of the polymorph spell. They are only the king *because of* the polymorph spell.
Lastly, if they say something like, "Show me the rightful king of Brittax," they may be guided towards a third NPC who would be the heir to the throne if it was known that the rightful king was dead.
Is the target *familiar* and *known to* the caster?
---------------------------------------------------
It's important to consider the limitations the spell places on who you can specifically locate. The spell description states:
>
> Describe or name a creature that is familiar to you.
>
>
> and
>
>
> The spell can locate a specific creature known to you, or the nearest creature of a specific kind (such as a human or a unicorn), so long as you have seen such a creature up close — within 30 feet — at least once.
>
>
>
This text is not overly clear, but it does suggest that if you've seen a specific creature within 30 feet they are known to you and the spell will work (barring other limitations). ***Familiar to you*** can mean a lot of things: It could mean you know of the person, or it could mean you are personally acquainted with them, or as the text suggests it could mean you have seen them once. As a GM, be sure to consider and interpret these statements when you resolve the effects of the spell. In the context of the party you describe it is very likely the PC has seen the potential targets of the spell. Also they may have met at other times in the campaign, or may just be known to the PC.
If I were the GM I would casually ask the spellcaster who they are targeting with the spell and apply the wording they use in-game to rule how the spell functions. As long as they are familiar with the target then the spell can locate that character.
In short
Yes the spell could fail, *and* you can play with the results depending on how the spellcaster PC words the spell and their familiarity with the target
-------------------------------------------------------------------------------------------------------------------------------------------------------
In regards to Nystal's Magic Aura, this spell would not affect *Locate Creature* in this case because the PC is attempting to locate a specific person, not a *type of creature*. NMA description states (PH 263):
>
> You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.
>
>
>
When *Locate Creature* is used to locate a single creature it is out of the scope of Nystal's Magic Aura because you are not looking for a *type* of creature. | Yes, but the spell fails for another reason
===========================================
*Nystal's Magic Aura* (MASK) states:
>
> You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.
>
>
>
The Mask is only changing the detected type or alignment of a creature. However, this isn't what *Locate Creature* is looking for:
>
> The spell can locate a specific creature known to you, or the nearest creature of a specific kind (such as a human or a unicorn), so long as you have seen such a creature up close--within 30 feet--at least once. If the creature you described or named is in a different form, such as being under the effects of a polymorph spell, this spell doesn't locate the creature.
>
>
>
As long as you *know* the True King, you can try and locate him. However, if you have not seen the True King, then he would not be a valid target for this as you don't actually know that there is a True King vs the False King.
For the sake of this question, let's say that the party *did* see the True King up close at one point and they attempt to *Locate* him at this party. If so, then *Nystal's Magic Aura* will do nothing to prevent the spell from working because it's only affecting knowing the False King's Type (humanoid?) or alignment via the Mask feature. In this case, the *Locate Creature* would not provide a direction unless the True King is within 1000' of the party. |
41,697,874 | I am very new to laravel, I saw that in every laravel tutorial there is Laravel homestead which is confusing for new learners. In fact, until now i don't understand what it is and why we are using it?
My question is very simple - can new learners start without homestead? Also I just wanted to know the importance of Laravel homestead in a very simple terms. | 2017/01/17 | [
"https://Stackoverflow.com/questions/41697874",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1385107/"
] | Laravel Homestead is just a virtual machine (VM). It helps in preventing polluting your development environment. Assume you have two projects. One project is based on Laravel 4 and the other is based on Laravel 5.3. Developing and testing of the two projects Without using a VM would land you into some problems. Do you install two web servers on you development machine?
Laravel docs do not go into the basics of why or hand hold you on the process. I would strongly recommend you look for [Jump Start PHP Environment](https://rads.stackoverflow.com/amzn/click/com/0994182643) by Bruno Skvorc. It is a short book but it holds your hand into why you need Homestead and also guides on how to configure the box. | Yes, you can learn without using homestead. Homestead is just a ready to go server instance that shares files with your host machine. It comes prepackaged with the 'recommended' versions of packages, so that all you need to do is spin it up and you're good to go. Some people can you wamp, or something similar, but keep in mind that all package dependencies and versions have to be updated and managed manually that way. I recommend finding a good tutorial for homestead to help get you setup, because its much easier to set it up than it is to setup a server on your own. |
41,697,874 | I am very new to laravel, I saw that in every laravel tutorial there is Laravel homestead which is confusing for new learners. In fact, until now i don't understand what it is and why we are using it?
My question is very simple - can new learners start without homestead? Also I just wanted to know the importance of Laravel homestead in a very simple terms. | 2017/01/17 | [
"https://Stackoverflow.com/questions/41697874",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/1385107/"
] | Laravel Homestead is just a virtual machine (VM). It helps in preventing polluting your development environment. Assume you have two projects. One project is based on Laravel 4 and the other is based on Laravel 5.3. Developing and testing of the two projects Without using a VM would land you into some problems. Do you install two web servers on you development machine?
Laravel docs do not go into the basics of why or hand hold you on the process. I would strongly recommend you look for [Jump Start PHP Environment](https://rads.stackoverflow.com/amzn/click/com/0994182643) by Bruno Skvorc. It is a short book but it holds your hand into why you need Homestead and also guides on how to configure the box. | Sure, You can go without homestead. You can use xampp, UwAmp, Wamp or any other server that's facilitating to execute php. Homestead is an environment that could also be used. Homestead is pre-packaged vagrant box with wonderful development environment. For more details just read <https://www.sitepoint.com/6-reasons-move-laravel-homestead/> |
106,225 | I am looking for a way to test whether a boundary threshold exists in a physiological response – a sample of the data is plotted below. My hypothesis is that the X-variable imposes a physiological constraint on Y-values, thus producing a boundary 'ceiling' for maximum Y-values that decreases at higher X-values (indicated by the red line on figure). I assume any Y-values below the boundary are limited by some other factor not included in this model.
Essentially, my goal is to determine if the boundary exists and if so to derive a confidence interval for the boundary line model – similar to a linear regression model, but describing the upper bound of the Y-values, rather than the center of mass.
I'm sure something like this exists, but I haven't come across it before. Also, I would appreciate any suggestions on a better title or tags for this post – I assume there are more accurate terms for what I'm describing that would help folks find this post.
 | 2014/07/08 | [
"https://stats.stackexchange.com/questions/106225",
"https://stats.stackexchange.com",
"https://stats.stackexchange.com/users/42170/"
] | You can use a permutation based test for such threshold.
[Permutation-based test](http://www.hydrol-earth-syst-sci.net/16/1255/2012/hess-16-1255-2012.pdf)
It tests the hypothesis whether a "data-sparse" region above the threshold line is due to a random chance or not.
In brief:
The basic idea behind is to calculate the area of the "data-sparse" region and use it as a statistic. The next step is to randomly permute the X-coordinates of the scatter-plot and repeat the calculation of the area of "data-sparse" region.
Probability p is the proportion of times the calculated area exceeded the original area. If p is sufficiently small the "data-sparse" region deemed to be significant. | I would start by finding the "upper envelope" of your data and then representing the "envelope" as a straight line or piece-wise linear function.
For starters, you could estimate the "envelope" as a piece-wise constant function f(x) =max(yk, given abs(x-xk) is below delta), where delta is a parameter, say 3 and (xk, yk) are your data points. Drawing a straight line through points (xk, f(xk)) should be straightforward :) |
106,225 | I am looking for a way to test whether a boundary threshold exists in a physiological response – a sample of the data is plotted below. My hypothesis is that the X-variable imposes a physiological constraint on Y-values, thus producing a boundary 'ceiling' for maximum Y-values that decreases at higher X-values (indicated by the red line on figure). I assume any Y-values below the boundary are limited by some other factor not included in this model.
Essentially, my goal is to determine if the boundary exists and if so to derive a confidence interval for the boundary line model – similar to a linear regression model, but describing the upper bound of the Y-values, rather than the center of mass.
I'm sure something like this exists, but I haven't come across it before. Also, I would appreciate any suggestions on a better title or tags for this post – I assume there are more accurate terms for what I'm describing that would help folks find this post.
 | 2014/07/08 | [
"https://stats.stackexchange.com/questions/106225",
"https://stats.stackexchange.com",
"https://stats.stackexchange.com/users/42170/"
] | You can use a permutation based test for such threshold.
[Permutation-based test](http://www.hydrol-earth-syst-sci.net/16/1255/2012/hess-16-1255-2012.pdf)
It tests the hypothesis whether a "data-sparse" region above the threshold line is due to a random chance or not.
In brief:
The basic idea behind is to calculate the area of the "data-sparse" region and use it as a statistic. The next step is to randomly permute the X-coordinates of the scatter-plot and repeat the calculation of the area of "data-sparse" region.
Probability p is the proportion of times the calculated area exceeded the original area. If p is sufficiently small the "data-sparse" region deemed to be significant. | This is potentially not the most robust solution. But you may be able to seriously improve the quality of the envelope using something along these lines:
1. break down your data into n intervals (where the number of intervals depends on the density of your data)
2. find the max of you data within each interval
3. Pass linear regression model though the selected maximum data points. |
14,511 | Is there any software for mac to create this particular 3d histogram:
given a matrix of value?
I've tried with Numbers but it doesn't have 3d histograms. | 2011/05/20 | [
"https://apple.stackexchange.com/questions/14511",
"https://apple.stackexchange.com",
"https://apple.stackexchange.com/users/1114/"
] | You can do things like that in [MatLab](http://www.mathworks.com/products/matlab/) or the free clone [Octave](http://www.gnu.org/software/octave/download.html). There's a script [here](http://daily-notes.net/2011/02/17/matlab-3d-histogram-and-surface-plot/). | [Grapher](http://guides.macrumors.com/Grapher) is probably the app you are looking for. It is already installed on your Mac by default. |
14,511 | Is there any software for mac to create this particular 3d histogram:
given a matrix of value?
I've tried with Numbers but it doesn't have 3d histograms. | 2011/05/20 | [
"https://apple.stackexchange.com/questions/14511",
"https://apple.stackexchange.com",
"https://apple.stackexchange.com/users/1114/"
] | You can do things like that in [MatLab](http://www.mathworks.com/products/matlab/) or the free clone [Octave](http://www.gnu.org/software/octave/download.html). There's a script [here](http://daily-notes.net/2011/02/17/matlab-3d-histogram-and-surface-plot/). | [LibreOffice](http://libreoffice.org/) (~ [OpenOffice](http://www.openoffice.org/) ~ [NeoOffice](http://www.neooffice.org)) to give some free office applications. |
14,511 | Is there any software for mac to create this particular 3d histogram:
given a matrix of value?
I've tried with Numbers but it doesn't have 3d histograms. | 2011/05/20 | [
"https://apple.stackexchange.com/questions/14511",
"https://apple.stackexchange.com",
"https://apple.stackexchange.com/users/1114/"
] | Microsoft Excel works for this sort of graph as well. | [R Studio](http://rstudio.org/) (the wonderful IDE for [R](http://cran.r-project.org/bin/macosx/)) can do this. It's the kind of the thing it was meant to do really. Free, open source and, IMO, easier to grasp than Octave (and free, wherease Matlab is most definitely not). You'll likely want the [RGL addon](http://www2.warwick.ac.uk/fac/sci/moac/students/peter_cock/r/3d_bar_chart) to do a 3D plot.
[There's a StackOverflow question that deals with how you go about plotting the 3D histogram in R](https://stackoverflow.com/questions/2405575/how-does-one-plot-a-3d-stacked-histogram-in-r). |
14,511 | Is there any software for mac to create this particular 3d histogram:
given a matrix of value?
I've tried with Numbers but it doesn't have 3d histograms. | 2011/05/20 | [
"https://apple.stackexchange.com/questions/14511",
"https://apple.stackexchange.com",
"https://apple.stackexchange.com/users/1114/"
] | [Mathematica](http://www.wolfram.com/mathematica/) is able to do this. | [R Studio](http://rstudio.org/) (the wonderful IDE for [R](http://cran.r-project.org/bin/macosx/)) can do this. It's the kind of the thing it was meant to do really. Free, open source and, IMO, easier to grasp than Octave (and free, wherease Matlab is most definitely not). You'll likely want the [RGL addon](http://www2.warwick.ac.uk/fac/sci/moac/students/peter_cock/r/3d_bar_chart) to do a 3D plot.
[There's a StackOverflow question that deals with how you go about plotting the 3D histogram in R](https://stackoverflow.com/questions/2405575/how-does-one-plot-a-3d-stacked-histogram-in-r). |
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