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3,659 | Mainly, how broad are Catholic academic journals? Do they ever deviate from the Vatican's opinion? If someone asks for a Catholic opinion, does that mean the typical Catholic layperson's opinion (may have expert knowledge and training on this subject), the Vatican's opinion (a very authoritative source), or heretical Catholic groups' opinions? | 2014/06/01 | [
"https://christianity.meta.stackexchange.com/questions/3659",
"https://christianity.meta.stackexchange.com",
"https://christianity.meta.stackexchange.com/users/4789/"
] | I dinged curiousdannii's answer because I don't think it's a good idea to assume any old Catholic Academic Journal to be non-heretical.
Check the [Newman guide](http://www.cardinalnewmansociety.org/TheNewmanGuide.aspx) to see if the university has accepted the Mandtadum from the local bishop to adhere to Catholic Principles there are also oaths of fidelity that Presidents and Theologians ought to take if they're to be taken seriously as a representative of the Catholic Faith. [this National Catholic Register article](http://www.ncregister.com/site/article/16007/) has more information on the oaths. | I'd say that if an answer references a publication from a particular Christian perspective then it should be assumed to be validly speaking for that perspective. If that's not the case then competing references can be present in the comments and the answer edited accordingly. |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | Being too focused on a problem prevents you from taking a step back. When you debug your code, you tend to needlessly repeat the same tests.
The more you try, the more you fail and you become very frustrated. Increased stress and frustration make things worse.
That's why quite often, a colleague can by chance, look over your shoulder, and point out the problem (and solution) in a few seconds.
They are not in the same **mental state** as you.
I often try to stop looking after a certain period of time and come back with a calmer mind a few hours later.
But the most powerful technique is just... **asking for help**. | I like to call it the ***incubation*** time on ideas and problems.
Your sub-conscience still continues to process the problem out of your awareness in a non-linear approach. This is very similar to what happens when you learn something new before you take a nap. Your mind has time to 'defragment' the information into ways that can be approached with greater flexibility.
Also, another helpful tip for overcoming being stuck on a bug, is called ***confessional de-bugging***. This is where you approach another person who does not know the problem and you begin to explain the problem. I find more often than not, that by just saying aloud the problem, the solution comes to mind.
check out these psych links:
[creativity tips](http://www.spring.org.uk/2010/03/boost-creativity-7-unusual-psychological-techniques.php?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3a%20PsychologyBlog%20%28PsyBlog%29) &
[problem napping](http://psychcentral.com/news/2011/03/09/light-sleep-facilitates-learning-process/24263.html) |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | Being too focused on a problem prevents you from taking a step back. When you debug your code, you tend to needlessly repeat the same tests.
The more you try, the more you fail and you become very frustrated. Increased stress and frustration make things worse.
That's why quite often, a colleague can by chance, look over your shoulder, and point out the problem (and solution) in a few seconds.
They are not in the same **mental state** as you.
I often try to stop looking after a certain period of time and come back with a calmer mind a few hours later.
But the most powerful technique is just... **asking for help**. | I fixed several critical bugs in my career, during shower time.
I am not a psychologist but I guess the difference is:
* sitting in front of the computer, I see source codes, breakpoints, `printf` outputs ...
* in the bathroom, codes run in my mind. |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | I fixed several critical bugs in my career, during shower time.
I am not a psychologist but I guess the difference is:
* sitting in front of the computer, I see source codes, breakpoints, `printf` outputs ...
* in the bathroom, codes run in my mind. | I've recently been using [the pomodoro technique](http://www.pomodorotechnique.com/) thanks to a suggestion from someone on this site, and think it provides a good answer to your question on timing and lengths of breaks. Basically, it has you work focused on a problem for 25 minutes, followed by a short 3-5 minute break, then a longer break after every 4 cycles of that. They cite some studies to back it up, but anecdotally I've found those intervals very effective.
I had thought the 25-minute spans would keep me from getting "in the zone," which people claim takes 15 minutes or so. On the contrary, with this timing I get in the zone almost immediately. I think that's because it's a lot easier to keep myself from being distracted when I know I only have to keep it up for 25 minutes. It's also easier to postpone external interruptions for only 25 minutes. It was much difficult before when I was trying to buckle down for 4 hours of work before lunch. |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | I'm not a psychologist, but when you're too concentrated on a single issue (finding the bug) you tend to lose the view for the larger system. But often the answer is not "down there" where you're currently looking for it but in someplace else - that you're not able to see at that point.
So what you really need to do is get out of the trenches and start looking at the whole system from a more general point of view - again. One tends to ignore this fact thinking "I really know it's right here, I just haven't found it yet". It happens to all of us, all the time. I even get to the point where I know "I can't find the bug using a good debugging technique so it **has** to be somewhere else" and still don't take the right thing and take a break - the human brain is such a funny thing.
However, it really doesn't matrer that much what you do - whether it's going to the bathroom, talking to a coworker or walking the dog. I used to go the a nearby store to buy some candies when I was stuck and as soon as I put my jacket on the solution popped into my head - almost everytime. It may also be a good thing to drink a lot of water during the time you're programming. It forces you to take a break every now and then to visit the bathroom and zap, there is the reason that forces you to break out of the trenches. | I like to call it the ***incubation*** time on ideas and problems.
Your sub-conscience still continues to process the problem out of your awareness in a non-linear approach. This is very similar to what happens when you learn something new before you take a nap. Your mind has time to 'defragment' the information into ways that can be approached with greater flexibility.
Also, another helpful tip for overcoming being stuck on a bug, is called ***confessional de-bugging***. This is where you approach another person who does not know the problem and you begin to explain the problem. I find more often than not, that by just saying aloud the problem, the solution comes to mind.
check out these psych links:
[creativity tips](http://www.spring.org.uk/2010/03/boost-creativity-7-unusual-psychological-techniques.php?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3a%20PsychologyBlog%20%28PsyBlog%29) &
[problem napping](http://psychcentral.com/news/2011/03/09/light-sleep-facilitates-learning-process/24263.html) |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | If you have been working on a problem for some time, your mind follows the patterns you setup during development. In other words, you develop temporary "black spots" for things outside of the mental frame you set up.
Taking your mind off the problem for a while helps removing this filter and allows you to mull things over without the filter in place.
What has often helped me in cases like these is to explain to someone else why it should work (when it doesn't) - normally halfway through your explanation you will realise where you went wrong in your reasoning or which step you missed.
Apart from developing a mental filter during development work, you brain is massively multi-threaded and often keeps going over a problem as part of unconsious processes. I sometimes use this by learning everything I can about a problem in an afternoon, then letting the problem lie for a day or 2 before working on a solution. | I fixed several critical bugs in my career, during shower time.
I am not a psychologist but I guess the difference is:
* sitting in front of the computer, I see source codes, breakpoints, `printf` outputs ...
* in the bathroom, codes run in my mind. |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | I guess your brain, like muscles, gets tired. Taking a break allows it to rest, top up with oxygen/fuel etc and start working again.
Going for a walk or taking exercise is often a good approach when you are really stuck with something. Even if you don't have a "eureka" moment it can often allow you to come back and take a new approach to solve the problem. | I've recently been using [the pomodoro technique](http://www.pomodorotechnique.com/) thanks to a suggestion from someone on this site, and think it provides a good answer to your question on timing and lengths of breaks. Basically, it has you work focused on a problem for 25 minutes, followed by a short 3-5 minute break, then a longer break after every 4 cycles of that. They cite some studies to back it up, but anecdotally I've found those intervals very effective.
I had thought the 25-minute spans would keep me from getting "in the zone," which people claim takes 15 minutes or so. On the contrary, with this timing I get in the zone almost immediately. I think that's because it's a lot easier to keep myself from being distracted when I know I only have to keep it up for 25 minutes. It's also easier to postpone external interruptions for only 25 minutes. It was much difficult before when I was trying to buckle down for 4 hours of work before lunch. |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | Being too focused on a problem prevents you from taking a step back. When you debug your code, you tend to needlessly repeat the same tests.
The more you try, the more you fail and you become very frustrated. Increased stress and frustration make things worse.
That's why quite often, a colleague can by chance, look over your shoulder, and point out the problem (and solution) in a few seconds.
They are not in the same **mental state** as you.
I often try to stop looking after a certain period of time and come back with a calmer mind a few hours later.
But the most powerful technique is just... **asking for help**. | >
> "We all get pricked by a **rose**
> sometimes. Sadly when we **concentrate**
> so much on the **pain** we **forget** about
> the **beauty** of the rose."
>
>
> |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | I'm not a psychologist, but when you're too concentrated on a single issue (finding the bug) you tend to lose the view for the larger system. But often the answer is not "down there" where you're currently looking for it but in someplace else - that you're not able to see at that point.
So what you really need to do is get out of the trenches and start looking at the whole system from a more general point of view - again. One tends to ignore this fact thinking "I really know it's right here, I just haven't found it yet". It happens to all of us, all the time. I even get to the point where I know "I can't find the bug using a good debugging technique so it **has** to be somewhere else" and still don't take the right thing and take a break - the human brain is such a funny thing.
However, it really doesn't matrer that much what you do - whether it's going to the bathroom, talking to a coworker or walking the dog. I used to go the a nearby store to buy some candies when I was stuck and as soon as I put my jacket on the solution popped into my head - almost everytime. It may also be a good thing to drink a lot of water during the time you're programming. It forces you to take a break every now and then to visit the bathroom and zap, there is the reason that forces you to break out of the trenches. | I've experienced the same phenomenon, and attributed it to looking at the problem with a different perspective as I spend time away from it (more time away implies a more distant perspective, approximately).
But there's another trick that I find accomplishes the same thing most of the time: explain the code to a co-worker. It's not for *them* to catch your bug, although they may; it's to force *you* to step back and explain the logic of the code at all relevant levels. I've never (though fair warning--sample size is limited) been able to subconsciously solve a bug that escaped this describe-to-coworker treatment. |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | Being too focused on a problem prevents you from taking a step back. When you debug your code, you tend to needlessly repeat the same tests.
The more you try, the more you fail and you become very frustrated. Increased stress and frustration make things worse.
That's why quite often, a colleague can by chance, look over your shoulder, and point out the problem (and solution) in a few seconds.
They are not in the same **mental state** as you.
I often try to stop looking after a certain period of time and come back with a calmer mind a few hours later.
But the most powerful technique is just... **asking for help**. | I've experienced the same phenomenon, and attributed it to looking at the problem with a different perspective as I spend time away from it (more time away implies a more distant perspective, approximately).
But there's another trick that I find accomplishes the same thing most of the time: explain the code to a co-worker. It's not for *them* to catch your bug, although they may; it's to force *you* to step back and explain the logic of the code at all relevant levels. I've never (though fair warning--sample size is limited) been able to subconsciously solve a bug that escaped this describe-to-coworker treatment. |
69,827 | Yesterday I spent a good part of the afternoon trying to fix a bug, which I thought to be trivial. I was going around in circles, not having a clue what was wrong. Rewriting large parts of the code. Checking on SO. Still no joy.
So I went home, walked the dog, watched a little TV and just before I went to sleep, bingo I realized the obvious mistake I was making. This morning it took about 10 minutes to fix.
While I was home, I wasn't actively thinking about the problem. Yet taking myself out of the situation enabled me to solve it.
It isn't the first time it has happened, and I know that it is a fairly common way to solve a programming problem. I have even heard of people dreaming the answers.
Why does this work?
Perhaps more importantly, is there a good guide as to when you should take a break from a problem, how long should the break be, and after how long does leaving a problem stop being effective?
I suppose I am trying to work out how to optimize this subconscious processing (or whatever is going on) | 2011/04/20 | [
"https://softwareengineering.stackexchange.com/questions/69827",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/10624/"
] | If you have been working on a problem for some time, your mind follows the patterns you setup during development. In other words, you develop temporary "black spots" for things outside of the mental frame you set up.
Taking your mind off the problem for a while helps removing this filter and allows you to mull things over without the filter in place.
What has often helped me in cases like these is to explain to someone else why it should work (when it doesn't) - normally halfway through your explanation you will realise where you went wrong in your reasoning or which step you missed.
Apart from developing a mental filter during development work, you brain is massively multi-threaded and often keeps going over a problem as part of unconsious processes. I sometimes use this by learning everything I can about a problem in an afternoon, then letting the problem lie for a day or 2 before working on a solution. | I've experienced the same phenomenon, and attributed it to looking at the problem with a different perspective as I spend time away from it (more time away implies a more distant perspective, approximately).
But there's another trick that I find accomplishes the same thing most of the time: explain the code to a co-worker. It's not for *them* to catch your bug, although they may; it's to force *you* to step back and explain the logic of the code at all relevant levels. I've never (though fair warning--sample size is limited) been able to subconsciously solve a bug that escaped this describe-to-coworker treatment. |
56,575 | If life were discovered in the supposed ocean on Europa, it would be a popular destination for scientists and researchers. I am curious as to what life on Europa would be like, in terms of engineering and building a sustainable habitat.
First, to reach the ocean, is it more practical to melt down through the ice, or drill it? How hard would the ice be at 10km thick (in 1/9th of Earths gravity)
If melting/drilling a tunnel down to the ocean, would it be possible to passively leave this borehole open, or would the pressures cause the ice to flow together again? What kind of engineering would be required to keep the borehole open, assuming my colonists want an elevator to the surface... how would tunnels and rooms at the bottom of the ice behave, structurally?
If the ocean was reached, at about 10km depth, the water pressure would be close to 100bar with some rough calculations. Would it be practical to build habitats mounted on the underside of the ice, in the water, or would drilling rooms within the ice be easier? | 2016/09/26 | [
"https://worldbuilding.stackexchange.com/questions/56575",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/27754/"
] | There have been reports of cryo-volcanoes and water ice geysers coming from Europa, most likely caused by cracks in the ice due to tidal forces.
It seems that rather than trying to drill through the ice the simplest thing would be to wait for natural crevices or other openings to form and then move in through them. Even if not naturally wide enough they would provide a starting point to help the drilling and the flow of water would carry away drilled ice.
Of course this would be risky as if the crevice started to close the forces involved would be immense, but that is a hazard faced by any attempt to penetrate the crust. Most likely we would be sending through unmanned vehicles, in which case they could be made small and just inserted through the crevices and cryo volcanoes directly with no need to drill at all. Some sort of swarm system with members of the swarm stopping at intervals to act as communications relays would make sense. | One thing which the other answers overlooked is the need for getting below the ice as quickly as possible. The immense radiation fields around Jupiter make this imperative, since humans and unprotected electronic devices will receive a lethal dose of radiation in a relatively short period of time. High speed is essential.
Because the ice is going to be as hard as rock on the surface, due to direct exposure to space and heat energy rapidly radiating away, there are a few possibilities. This [technique](http://www.nextbigfuture.com/2015/07/drilling-10-times-faster-than-ever.html) uses high speed projectiles fired down a tube to strike the working face at speeds measured in kilometres per second. This sort of energy would shatter rock. In the case of ice, it would shatter the ice and possibly melt the walls of the tube, providing an impromptu smooth surface to lay down the actual tunnel walls (for insulation and to economize on materials, a foamed material made from silicate rocks imported from another Jovian moon should suffice).
[](https://i.stack.imgur.com/q9NM4.png)
*Ram Accelerator schematic*
Hammering the ice like this has a disadvantage in that there will be large areas of cracked ice radiating away from the tunnel exterior. This broken ice may eventually "flow" back together from static pressure and the action of the Jovian tides, but that is both long term and does not have the sort of quality control that engineered solutions havre.
As an alternative, if the spaceships and landers have fusion or nuclear drives, the power of the exhaust could be used to rapidly melts through the ice. The jet of plasma will rapidly melt through the ice, and one issue would be the venting of clouds of steam released by the process, or protecting the dismounted engine assembly while it cuts through the ice. Conceptually, the engine could be held in an articulating frame which grips the sides of the tunnel and can point the exhaust plume in the desired direction. After the ice has melted and the steam cleared, the frame can be "walked" by moving the supporting legs, while a "finishing machine" follows and lines the tunnel. This method also allows the device to carve larger chambers in the ice, once sufficient depth was reached for radiation protection. The frame can be swivelled so the exhaust plume moves in a cone or spiral shape to excavate larger areas under the ice.
[](https://i.stack.imgur.com/ccrGC.jpg)
*If a small plasma cutter can rapidly carve through steel, ice should not be an issue*
While there will also be a problem of cracks radiating away from the tunnel or opening, the heat energy should be able to create a relatively thick wall of fresh ice, providing support until the engineers can stabilize the area with "Rock bolts", injecting hot water like grout to fill and seal cracks (something like a giant Zamboni machine used to prepare ice surfaces at arenas), and liners installed.
To protect the tunnel from damage caused by heat leakage from the base, insulating the base from the intense cold and protecting the base from the inevitable movement of the ice, I believe the best solution there would be to have an inner liner with separation between the ice walls and the manned part of the base, like an insulated flask.
Several of these ideas could be used in conjunction with each other. The Ram accelerator could be used to drill pilot holes for the dismounted fusion engine to direct the exhaust plume. Extra holes could be drilled in parallel so when the main jet is used, steam can flow into the parallel tunnels through cracks in the ice and escape, protecting the driving platform from working in a steam bath. Even the meltwater could be pumped into forms and refrozen to create bricks of pure ice, free of trapped gasses and having no internal flaws or cracks. These ice bricks can then be used to create the initial liner of the tunnel, much like a barrel vault except completely circular.
Drilling is relatively well known technology. The difference here is you need to drill deeply and rapidly, in order to make livable structures in a reasonable time. |
56,575 | If life were discovered in the supposed ocean on Europa, it would be a popular destination for scientists and researchers. I am curious as to what life on Europa would be like, in terms of engineering and building a sustainable habitat.
First, to reach the ocean, is it more practical to melt down through the ice, or drill it? How hard would the ice be at 10km thick (in 1/9th of Earths gravity)
If melting/drilling a tunnel down to the ocean, would it be possible to passively leave this borehole open, or would the pressures cause the ice to flow together again? What kind of engineering would be required to keep the borehole open, assuming my colonists want an elevator to the surface... how would tunnels and rooms at the bottom of the ice behave, structurally?
If the ocean was reached, at about 10km depth, the water pressure would be close to 100bar with some rough calculations. Would it be practical to build habitats mounted on the underside of the ice, in the water, or would drilling rooms within the ice be easier? | 2016/09/26 | [
"https://worldbuilding.stackexchange.com/questions/56575",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/27754/"
] | It is much more practical to melt through ice than to drill through it. The most likely way of doing this is to place either radiothermalgenerators or a reactor on the front of your craft.
It would not be possible to keep the borehole open after passing through without installing a thick steel tube the full width and length of the tunnel. This would still snap as soon as the ice moved though (which might happen every Europan day due to tidal forces). [correction: Europa is tidally locked and thus has no days.]
My rough calculations suggest 133 bar, which is more or less what you got. This is roughly 3x greater pressure than modern large submarines are able to survive, so your pipe would have to be roughly 3 times stronger than a Seawolf pressure hull. That is a heck of a lot of material to cart across the solar system, and any flaw in its entire 10km length would result in collapse.
If it was absolutely necessary for your story, I would probably build the tunnel from some modern version of Pykrete. <https://en.wikipedia.org/wiki/Pykrete> Perhaps using a carbon nanotube fiber rather than cellulose (and ideally manufacturing the CNT on site). You would probably do best to situate the tunnel at a point which experiences the least ice movement. (Presumably far from any fault zone.)
Ice at the bottom of the hole would presumably not be very strong as it is under enough pressure that it is very close to becoming liquid again. You should transition away from Pykrete before reaching the water layer, and use some other material.
This whole endeavor is pretty unrealistic with any technology we are likely to have in the next 100 years though. (IMHO) By the time humans have the technology to do something like physically surviving a trip to the Europan ocean, they will have long since developed many technologies which would undermine the plot of this story, like very advanced genetic engineering which make humanity unrecognizable to readers, super tough nanobots who would have already scouted the Europan oceans quite thoroughly, and super advanced sensors which would have scanned the Europan oceans in detail right through the 10km of ice.
Also, it's likely that if life were discovered on Europa (especially macroscopic life) the entire moon would be utterly and completely off limits to human explorers for fear of contamination.
---
I just read JDługosz's answer and he makes a lot of good points that have made me rethink my answer.
Ok, the mass of the ice column that needs to be removed is M=density×height×π×r². Let's say the radius of the hole is 5 meters. Based on that I'm getting a mass of the column of 7.2E9 kg (neglecting the compressibility of ice). For the potential energy of raising those tailings to the surface I'm getting 11 MW years. (11 megawatts for 1 year). If your removal system is 50% efficient that would require a 22 MW (electrical) reactor, which is pretty serious hardware. At 35% efficiency, that would put out 64MW (thermal). Your boring machine is going to need more power to run the cutters, but I have no idea how to calculate this.
The energy needed to raise the temperature of the ice column to −50° C (which, from the phase diagram of water, appears to be the temperature needed to sublimate ice rapidly in a vacuum) is E = mass × specific heat × change in temperature. The specific heat of ice is roughly 2000 joules/kg°C. I'm getting a heat energy of 1.7E15 joules or 52 MW years (thermal).
The enthalpy of fusion of ice is 333KJ/KG. The enthalpy of vaporization of steam is 2257KJ/KG. I assume you just add these two together to get the enthalpy of sublimation? (I never did that in school.) That gives me a 1.86E16 joules to phase change the ice to steam or 589MW years, which is a really shockingly large number.
It also occurred to me after reading JDługosz's post that the sublimated ice would possibly recondense on the walls of the tunnel (although maybe not if the tunnel is in vacuum?) Regardless, the tunnel should probably be insulated in a melting scenario.
Regardless the vast majority of the energy need for the melting and vaporization plan goes into the boiling part of the phase change (rather than the melting part). This makes intuitive sense now that I think about it. Water quenching of hot things is crazily effective, and I once saw a TV show demonstrate that melting a hole through a glacier was way more efficient than drilling.
Based on these results, and taking into account the (probably) infeasibility of shoring up the tunnel, I would like to propose a new solution.
Covering the tunnel mouth with a lid to keep it pressurized to roughly 1 atmosphere. You still melt your way through the ice, but now you coat the interior of the ice tunnel with insulation rather than shoring. (Pykrete makes a great outer layer of insulation, but you would want something else on the inner layer.) Melted water stays liquid, meaning you don't have to spend energy boiling it off. This reduces the phase change energy requirements from 589MWY to 87MWY. Adding that to the temperature rise energy of 77MWY (you now need 0 degrees C, so this is a little higher than before) leaves you with 183MWY (thermal), which is still a heck of a lot of energy. I didn't even include the heat loss through the walls of the tunnel, but I think it's the least challenging part of the entire mission. Especially since the reactor needs no coolant radiators which, on a space ship in vacuum, would be enormous.
The weight of the water maintains more than enough pressure on the walls to keep them from collapsing. The reactor heat drills the hole without the need for thousands of tons of drilling equipment (and repair parts and machinery to let you install the repair parts) and ... billions (?) of tons of shoring.
Your explorers would need to live inside a super strong submarine which is 3 times stronger than a modern military submarine, but much less strong than the Alvin deep sea submersible. (The submarine would serve as an excellent space habitat by the way.) The reactor would need to be kept running permanently in order to prevent the column of water from refreezing, so you wouldn't just let it drop into the ocean once you broke through the ice. Probably the biggest challenge is now the mass of the insulation.
It would be really cool if there was a good way to manufacture cellulose (or other similarly performing polymer) from materials found on Europa. The ice on Europa is not 100% water. <http://people.virginia.edu/~rej/papers09/Carlson4019.pdf> Perhaps the ammonia and carbon dioxide ices can be used as feed stocks in a small factory to produce a hydrophilic polymer? The inner surface of the insulation might be a gel or a hydrate of some sort? You want something where most of the mass of the insulator is water, which is captured and held immobile. | There have been reports of cryo-volcanoes and water ice geysers coming from Europa, most likely caused by cracks in the ice due to tidal forces.
It seems that rather than trying to drill through the ice the simplest thing would be to wait for natural crevices or other openings to form and then move in through them. Even if not naturally wide enough they would provide a starting point to help the drilling and the flow of water would carry away drilled ice.
Of course this would be risky as if the crevice started to close the forces involved would be immense, but that is a hazard faced by any attempt to penetrate the crust. Most likely we would be sending through unmanned vehicles, in which case they could be made small and just inserted through the crevices and cryo volcanoes directly with no need to drill at all. Some sort of swarm system with members of the swarm stopping at intervals to act as communications relays would make sense. |
56,575 | If life were discovered in the supposed ocean on Europa, it would be a popular destination for scientists and researchers. I am curious as to what life on Europa would be like, in terms of engineering and building a sustainable habitat.
First, to reach the ocean, is it more practical to melt down through the ice, or drill it? How hard would the ice be at 10km thick (in 1/9th of Earths gravity)
If melting/drilling a tunnel down to the ocean, would it be possible to passively leave this borehole open, or would the pressures cause the ice to flow together again? What kind of engineering would be required to keep the borehole open, assuming my colonists want an elevator to the surface... how would tunnels and rooms at the bottom of the ice behave, structurally?
If the ocean was reached, at about 10km depth, the water pressure would be close to 100bar with some rough calculations. Would it be practical to build habitats mounted on the underside of the ice, in the water, or would drilling rooms within the ice be easier? | 2016/09/26 | [
"https://worldbuilding.stackexchange.com/questions/56575",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/27754/"
] | It is much more practical to drill (or tunnel or quarry) than it would be to melt the ice.
Consider: we have tunnel boring machines and other excavating techniques here. Do we melt the rock into lava and pump that? No, we just cary it away in chunks.
On a cold world, ice is a mineral. So think of it like rock.
To melt it, you have to raise [its temperature](https://en.wikipedia.org/wiki/Europa_(moon)#Subsurface_ocean) from a mean of −170°C up to 0 while the surrounding material is conducting the heat away, and then further add the amount of energy that would have raised the temperature of ice 80° before it budges again—the *heat of fusion*.
Then you *still* have not supplied the energy needed to lift the material out of the hole. And it has to be well insulated to be piped because it’s surrounded by cold.
(People in colder climates have to shift ice off roads and driveways. Do you ever melt it and drain the water? Or is it easier to just shift it while in solid form?)
Finally, the ice is ductile and under high pressure: the hole has to be kept open by adding a liner as you go (in the manner of tunnel boring machines) or filling it with a dense fluid (in the manner of oil/gas wells). Simply adding fiber to the ice to make a composite will not be anywhere near strong enough. A back of the envelope calculation indicates a pressure of 2 MPa (13% of the Earth weight of a column of ice 15 km tall). Note that on Earth the glaciers are fluid at the bottom under pressure, and rock is fluid in the pressure of the mantle. The top (ultracold) will have the consistency of granite and the bottom (ultra pressure and warm) like roofing tar.
The best way to tunnel will the same as how we treat hard rock here: apply pressure to shatter it, then sweep out the pieces. Think about oil drilling bits as your model. You have the further advantage in that ice is rather light weight, so you can arrange for it to float in the drilling fluid. That makes it easy to keep the chips away from the working face when digging straight down.
Maybe you won’t use teeth or pressure to crack off chips, but can use radiation (microwaves or lasers) to melt small spots and crack the working face into chips without using mechanical wearing tools. But, you don’t have to melt the *whole thing*!
For *much* more on ice mantles in general, see [this talk](http://www.seti.org/weeky-lecture/convection-ice-mantles-effects-texture-and-anisotropy) in the SETI weekly colloquium series. Europa in particular appears to have a “cold, static lid”.
summary
=======
The advantage of melting is the lack of complex moving machinery. But you’re not talking about getting a small probe through the ice without leaving a hole; you want to leave a (rather large) hole as a perminant access point. So you *do* need complex moving machines to lay the liner, and material must be evaculated.
Melting requires significant amounts of power, and must be intense enough to not be carried off by surrounding material.
I suspect that different techniques will be applicable at different depths, and you may include *cooling* the deeper part to stabilize the material! | There have been reports of cryo-volcanoes and water ice geysers coming from Europa, most likely caused by cracks in the ice due to tidal forces.
It seems that rather than trying to drill through the ice the simplest thing would be to wait for natural crevices or other openings to form and then move in through them. Even if not naturally wide enough they would provide a starting point to help the drilling and the flow of water would carry away drilled ice.
Of course this would be risky as if the crevice started to close the forces involved would be immense, but that is a hazard faced by any attempt to penetrate the crust. Most likely we would be sending through unmanned vehicles, in which case they could be made small and just inserted through the crevices and cryo volcanoes directly with no need to drill at all. Some sort of swarm system with members of the swarm stopping at intervals to act as communications relays would make sense. |
56,575 | If life were discovered in the supposed ocean on Europa, it would be a popular destination for scientists and researchers. I am curious as to what life on Europa would be like, in terms of engineering and building a sustainable habitat.
First, to reach the ocean, is it more practical to melt down through the ice, or drill it? How hard would the ice be at 10km thick (in 1/9th of Earths gravity)
If melting/drilling a tunnel down to the ocean, would it be possible to passively leave this borehole open, or would the pressures cause the ice to flow together again? What kind of engineering would be required to keep the borehole open, assuming my colonists want an elevator to the surface... how would tunnels and rooms at the bottom of the ice behave, structurally?
If the ocean was reached, at about 10km depth, the water pressure would be close to 100bar with some rough calculations. Would it be practical to build habitats mounted on the underside of the ice, in the water, or would drilling rooms within the ice be easier? | 2016/09/26 | [
"https://worldbuilding.stackexchange.com/questions/56575",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/27754/"
] | It is much more practical to drill (or tunnel or quarry) than it would be to melt the ice.
Consider: we have tunnel boring machines and other excavating techniques here. Do we melt the rock into lava and pump that? No, we just cary it away in chunks.
On a cold world, ice is a mineral. So think of it like rock.
To melt it, you have to raise [its temperature](https://en.wikipedia.org/wiki/Europa_(moon)#Subsurface_ocean) from a mean of −170°C up to 0 while the surrounding material is conducting the heat away, and then further add the amount of energy that would have raised the temperature of ice 80° before it budges again—the *heat of fusion*.
Then you *still* have not supplied the energy needed to lift the material out of the hole. And it has to be well insulated to be piped because it’s surrounded by cold.
(People in colder climates have to shift ice off roads and driveways. Do you ever melt it and drain the water? Or is it easier to just shift it while in solid form?)
Finally, the ice is ductile and under high pressure: the hole has to be kept open by adding a liner as you go (in the manner of tunnel boring machines) or filling it with a dense fluid (in the manner of oil/gas wells). Simply adding fiber to the ice to make a composite will not be anywhere near strong enough. A back of the envelope calculation indicates a pressure of 2 MPa (13% of the Earth weight of a column of ice 15 km tall). Note that on Earth the glaciers are fluid at the bottom under pressure, and rock is fluid in the pressure of the mantle. The top (ultracold) will have the consistency of granite and the bottom (ultra pressure and warm) like roofing tar.
The best way to tunnel will the same as how we treat hard rock here: apply pressure to shatter it, then sweep out the pieces. Think about oil drilling bits as your model. You have the further advantage in that ice is rather light weight, so you can arrange for it to float in the drilling fluid. That makes it easy to keep the chips away from the working face when digging straight down.
Maybe you won’t use teeth or pressure to crack off chips, but can use radiation (microwaves or lasers) to melt small spots and crack the working face into chips without using mechanical wearing tools. But, you don’t have to melt the *whole thing*!
For *much* more on ice mantles in general, see [this talk](http://www.seti.org/weeky-lecture/convection-ice-mantles-effects-texture-and-anisotropy) in the SETI weekly colloquium series. Europa in particular appears to have a “cold, static lid”.
summary
=======
The advantage of melting is the lack of complex moving machinery. But you’re not talking about getting a small probe through the ice without leaving a hole; you want to leave a (rather large) hole as a perminant access point. So you *do* need complex moving machines to lay the liner, and material must be evaculated.
Melting requires significant amounts of power, and must be intense enough to not be carried off by surrounding material.
I suspect that different techniques will be applicable at different depths, and you may include *cooling* the deeper part to stabilize the material! | when drilling/melting a hole in such a cold environment one important factor is time taken for the new ice layers to form. So the process should be as quickly as possible or we could figure out ways to prevent ice sheets from forming in a localized area.
>
> Ice forms When the water molecules move slowly because of low energy
> and it is easier for them to hook on to each other by sharing
> electrons. when salt is added salt molecules arrange themselves around
> the water molecules like little fences and keep the water molecules
> from hooking together. But if it gets cold enough, about 28.5 degrees
> Fahrenheit or -2 Celsius, ocean water will freeze too.
>
>
>
**source**: <http://quatr.us/chemistry/atoms/ice.htm>
So If we are able to build nano structures that can prevent water molecules from hooking easily while staying localized to that particular area and be degradable easily after sometime. Then we just have to put the nano material and wait without worrying of contaminating alien environment. There have been some research going in [this](http://www.livescience.com/8947-cool-tech-materials-prevent-ice-formation.html) area |
56,575 | If life were discovered in the supposed ocean on Europa, it would be a popular destination for scientists and researchers. I am curious as to what life on Europa would be like, in terms of engineering and building a sustainable habitat.
First, to reach the ocean, is it more practical to melt down through the ice, or drill it? How hard would the ice be at 10km thick (in 1/9th of Earths gravity)
If melting/drilling a tunnel down to the ocean, would it be possible to passively leave this borehole open, or would the pressures cause the ice to flow together again? What kind of engineering would be required to keep the borehole open, assuming my colonists want an elevator to the surface... how would tunnels and rooms at the bottom of the ice behave, structurally?
If the ocean was reached, at about 10km depth, the water pressure would be close to 100bar with some rough calculations. Would it be practical to build habitats mounted on the underside of the ice, in the water, or would drilling rooms within the ice be easier? | 2016/09/26 | [
"https://worldbuilding.stackexchange.com/questions/56575",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/27754/"
] | when drilling/melting a hole in such a cold environment one important factor is time taken for the new ice layers to form. So the process should be as quickly as possible or we could figure out ways to prevent ice sheets from forming in a localized area.
>
> Ice forms When the water molecules move slowly because of low energy
> and it is easier for them to hook on to each other by sharing
> electrons. when salt is added salt molecules arrange themselves around
> the water molecules like little fences and keep the water molecules
> from hooking together. But if it gets cold enough, about 28.5 degrees
> Fahrenheit or -2 Celsius, ocean water will freeze too.
>
>
>
**source**: <http://quatr.us/chemistry/atoms/ice.htm>
So If we are able to build nano structures that can prevent water molecules from hooking easily while staying localized to that particular area and be degradable easily after sometime. Then we just have to put the nano material and wait without worrying of contaminating alien environment. There have been some research going in [this](http://www.livescience.com/8947-cool-tech-materials-prevent-ice-formation.html) area | One thing which the other answers overlooked is the need for getting below the ice as quickly as possible. The immense radiation fields around Jupiter make this imperative, since humans and unprotected electronic devices will receive a lethal dose of radiation in a relatively short period of time. High speed is essential.
Because the ice is going to be as hard as rock on the surface, due to direct exposure to space and heat energy rapidly radiating away, there are a few possibilities. This [technique](http://www.nextbigfuture.com/2015/07/drilling-10-times-faster-than-ever.html) uses high speed projectiles fired down a tube to strike the working face at speeds measured in kilometres per second. This sort of energy would shatter rock. In the case of ice, it would shatter the ice and possibly melt the walls of the tube, providing an impromptu smooth surface to lay down the actual tunnel walls (for insulation and to economize on materials, a foamed material made from silicate rocks imported from another Jovian moon should suffice).
[](https://i.stack.imgur.com/q9NM4.png)
*Ram Accelerator schematic*
Hammering the ice like this has a disadvantage in that there will be large areas of cracked ice radiating away from the tunnel exterior. This broken ice may eventually "flow" back together from static pressure and the action of the Jovian tides, but that is both long term and does not have the sort of quality control that engineered solutions havre.
As an alternative, if the spaceships and landers have fusion or nuclear drives, the power of the exhaust could be used to rapidly melts through the ice. The jet of plasma will rapidly melt through the ice, and one issue would be the venting of clouds of steam released by the process, or protecting the dismounted engine assembly while it cuts through the ice. Conceptually, the engine could be held in an articulating frame which grips the sides of the tunnel and can point the exhaust plume in the desired direction. After the ice has melted and the steam cleared, the frame can be "walked" by moving the supporting legs, while a "finishing machine" follows and lines the tunnel. This method also allows the device to carve larger chambers in the ice, once sufficient depth was reached for radiation protection. The frame can be swivelled so the exhaust plume moves in a cone or spiral shape to excavate larger areas under the ice.
[](https://i.stack.imgur.com/ccrGC.jpg)
*If a small plasma cutter can rapidly carve through steel, ice should not be an issue*
While there will also be a problem of cracks radiating away from the tunnel or opening, the heat energy should be able to create a relatively thick wall of fresh ice, providing support until the engineers can stabilize the area with "Rock bolts", injecting hot water like grout to fill and seal cracks (something like a giant Zamboni machine used to prepare ice surfaces at arenas), and liners installed.
To protect the tunnel from damage caused by heat leakage from the base, insulating the base from the intense cold and protecting the base from the inevitable movement of the ice, I believe the best solution there would be to have an inner liner with separation between the ice walls and the manned part of the base, like an insulated flask.
Several of these ideas could be used in conjunction with each other. The Ram accelerator could be used to drill pilot holes for the dismounted fusion engine to direct the exhaust plume. Extra holes could be drilled in parallel so when the main jet is used, steam can flow into the parallel tunnels through cracks in the ice and escape, protecting the driving platform from working in a steam bath. Even the meltwater could be pumped into forms and refrozen to create bricks of pure ice, free of trapped gasses and having no internal flaws or cracks. These ice bricks can then be used to create the initial liner of the tunnel, much like a barrel vault except completely circular.
Drilling is relatively well known technology. The difference here is you need to drill deeply and rapidly, in order to make livable structures in a reasonable time. |
56,575 | If life were discovered in the supposed ocean on Europa, it would be a popular destination for scientists and researchers. I am curious as to what life on Europa would be like, in terms of engineering and building a sustainable habitat.
First, to reach the ocean, is it more practical to melt down through the ice, or drill it? How hard would the ice be at 10km thick (in 1/9th of Earths gravity)
If melting/drilling a tunnel down to the ocean, would it be possible to passively leave this borehole open, or would the pressures cause the ice to flow together again? What kind of engineering would be required to keep the borehole open, assuming my colonists want an elevator to the surface... how would tunnels and rooms at the bottom of the ice behave, structurally?
If the ocean was reached, at about 10km depth, the water pressure would be close to 100bar with some rough calculations. Would it be practical to build habitats mounted on the underside of the ice, in the water, or would drilling rooms within the ice be easier? | 2016/09/26 | [
"https://worldbuilding.stackexchange.com/questions/56575",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/27754/"
] | It is much more practical to melt through ice than to drill through it. The most likely way of doing this is to place either radiothermalgenerators or a reactor on the front of your craft.
It would not be possible to keep the borehole open after passing through without installing a thick steel tube the full width and length of the tunnel. This would still snap as soon as the ice moved though (which might happen every Europan day due to tidal forces). [correction: Europa is tidally locked and thus has no days.]
My rough calculations suggest 133 bar, which is more or less what you got. This is roughly 3x greater pressure than modern large submarines are able to survive, so your pipe would have to be roughly 3 times stronger than a Seawolf pressure hull. That is a heck of a lot of material to cart across the solar system, and any flaw in its entire 10km length would result in collapse.
If it was absolutely necessary for your story, I would probably build the tunnel from some modern version of Pykrete. <https://en.wikipedia.org/wiki/Pykrete> Perhaps using a carbon nanotube fiber rather than cellulose (and ideally manufacturing the CNT on site). You would probably do best to situate the tunnel at a point which experiences the least ice movement. (Presumably far from any fault zone.)
Ice at the bottom of the hole would presumably not be very strong as it is under enough pressure that it is very close to becoming liquid again. You should transition away from Pykrete before reaching the water layer, and use some other material.
This whole endeavor is pretty unrealistic with any technology we are likely to have in the next 100 years though. (IMHO) By the time humans have the technology to do something like physically surviving a trip to the Europan ocean, they will have long since developed many technologies which would undermine the plot of this story, like very advanced genetic engineering which make humanity unrecognizable to readers, super tough nanobots who would have already scouted the Europan oceans quite thoroughly, and super advanced sensors which would have scanned the Europan oceans in detail right through the 10km of ice.
Also, it's likely that if life were discovered on Europa (especially macroscopic life) the entire moon would be utterly and completely off limits to human explorers for fear of contamination.
---
I just read JDługosz's answer and he makes a lot of good points that have made me rethink my answer.
Ok, the mass of the ice column that needs to be removed is M=density×height×π×r². Let's say the radius of the hole is 5 meters. Based on that I'm getting a mass of the column of 7.2E9 kg (neglecting the compressibility of ice). For the potential energy of raising those tailings to the surface I'm getting 11 MW years. (11 megawatts for 1 year). If your removal system is 50% efficient that would require a 22 MW (electrical) reactor, which is pretty serious hardware. At 35% efficiency, that would put out 64MW (thermal). Your boring machine is going to need more power to run the cutters, but I have no idea how to calculate this.
The energy needed to raise the temperature of the ice column to −50° C (which, from the phase diagram of water, appears to be the temperature needed to sublimate ice rapidly in a vacuum) is E = mass × specific heat × change in temperature. The specific heat of ice is roughly 2000 joules/kg°C. I'm getting a heat energy of 1.7E15 joules or 52 MW years (thermal).
The enthalpy of fusion of ice is 333KJ/KG. The enthalpy of vaporization of steam is 2257KJ/KG. I assume you just add these two together to get the enthalpy of sublimation? (I never did that in school.) That gives me a 1.86E16 joules to phase change the ice to steam or 589MW years, which is a really shockingly large number.
It also occurred to me after reading JDługosz's post that the sublimated ice would possibly recondense on the walls of the tunnel (although maybe not if the tunnel is in vacuum?) Regardless, the tunnel should probably be insulated in a melting scenario.
Regardless the vast majority of the energy need for the melting and vaporization plan goes into the boiling part of the phase change (rather than the melting part). This makes intuitive sense now that I think about it. Water quenching of hot things is crazily effective, and I once saw a TV show demonstrate that melting a hole through a glacier was way more efficient than drilling.
Based on these results, and taking into account the (probably) infeasibility of shoring up the tunnel, I would like to propose a new solution.
Covering the tunnel mouth with a lid to keep it pressurized to roughly 1 atmosphere. You still melt your way through the ice, but now you coat the interior of the ice tunnel with insulation rather than shoring. (Pykrete makes a great outer layer of insulation, but you would want something else on the inner layer.) Melted water stays liquid, meaning you don't have to spend energy boiling it off. This reduces the phase change energy requirements from 589MWY to 87MWY. Adding that to the temperature rise energy of 77MWY (you now need 0 degrees C, so this is a little higher than before) leaves you with 183MWY (thermal), which is still a heck of a lot of energy. I didn't even include the heat loss through the walls of the tunnel, but I think it's the least challenging part of the entire mission. Especially since the reactor needs no coolant radiators which, on a space ship in vacuum, would be enormous.
The weight of the water maintains more than enough pressure on the walls to keep them from collapsing. The reactor heat drills the hole without the need for thousands of tons of drilling equipment (and repair parts and machinery to let you install the repair parts) and ... billions (?) of tons of shoring.
Your explorers would need to live inside a super strong submarine which is 3 times stronger than a modern military submarine, but much less strong than the Alvin deep sea submersible. (The submarine would serve as an excellent space habitat by the way.) The reactor would need to be kept running permanently in order to prevent the column of water from refreezing, so you wouldn't just let it drop into the ocean once you broke through the ice. Probably the biggest challenge is now the mass of the insulation.
It would be really cool if there was a good way to manufacture cellulose (or other similarly performing polymer) from materials found on Europa. The ice on Europa is not 100% water. <http://people.virginia.edu/~rej/papers09/Carlson4019.pdf> Perhaps the ammonia and carbon dioxide ices can be used as feed stocks in a small factory to produce a hydrophilic polymer? The inner surface of the insulation might be a gel or a hydrate of some sort? You want something where most of the mass of the insulator is water, which is captured and held immobile. | One thing which the other answers overlooked is the need for getting below the ice as quickly as possible. The immense radiation fields around Jupiter make this imperative, since humans and unprotected electronic devices will receive a lethal dose of radiation in a relatively short period of time. High speed is essential.
Because the ice is going to be as hard as rock on the surface, due to direct exposure to space and heat energy rapidly radiating away, there are a few possibilities. This [technique](http://www.nextbigfuture.com/2015/07/drilling-10-times-faster-than-ever.html) uses high speed projectiles fired down a tube to strike the working face at speeds measured in kilometres per second. This sort of energy would shatter rock. In the case of ice, it would shatter the ice and possibly melt the walls of the tube, providing an impromptu smooth surface to lay down the actual tunnel walls (for insulation and to economize on materials, a foamed material made from silicate rocks imported from another Jovian moon should suffice).
[](https://i.stack.imgur.com/q9NM4.png)
*Ram Accelerator schematic*
Hammering the ice like this has a disadvantage in that there will be large areas of cracked ice radiating away from the tunnel exterior. This broken ice may eventually "flow" back together from static pressure and the action of the Jovian tides, but that is both long term and does not have the sort of quality control that engineered solutions havre.
As an alternative, if the spaceships and landers have fusion or nuclear drives, the power of the exhaust could be used to rapidly melts through the ice. The jet of plasma will rapidly melt through the ice, and one issue would be the venting of clouds of steam released by the process, or protecting the dismounted engine assembly while it cuts through the ice. Conceptually, the engine could be held in an articulating frame which grips the sides of the tunnel and can point the exhaust plume in the desired direction. After the ice has melted and the steam cleared, the frame can be "walked" by moving the supporting legs, while a "finishing machine" follows and lines the tunnel. This method also allows the device to carve larger chambers in the ice, once sufficient depth was reached for radiation protection. The frame can be swivelled so the exhaust plume moves in a cone or spiral shape to excavate larger areas under the ice.
[](https://i.stack.imgur.com/ccrGC.jpg)
*If a small plasma cutter can rapidly carve through steel, ice should not be an issue*
While there will also be a problem of cracks radiating away from the tunnel or opening, the heat energy should be able to create a relatively thick wall of fresh ice, providing support until the engineers can stabilize the area with "Rock bolts", injecting hot water like grout to fill and seal cracks (something like a giant Zamboni machine used to prepare ice surfaces at arenas), and liners installed.
To protect the tunnel from damage caused by heat leakage from the base, insulating the base from the intense cold and protecting the base from the inevitable movement of the ice, I believe the best solution there would be to have an inner liner with separation between the ice walls and the manned part of the base, like an insulated flask.
Several of these ideas could be used in conjunction with each other. The Ram accelerator could be used to drill pilot holes for the dismounted fusion engine to direct the exhaust plume. Extra holes could be drilled in parallel so when the main jet is used, steam can flow into the parallel tunnels through cracks in the ice and escape, protecting the driving platform from working in a steam bath. Even the meltwater could be pumped into forms and refrozen to create bricks of pure ice, free of trapped gasses and having no internal flaws or cracks. These ice bricks can then be used to create the initial liner of the tunnel, much like a barrel vault except completely circular.
Drilling is relatively well known technology. The difference here is you need to drill deeply and rapidly, in order to make livable structures in a reasonable time. |
56,575 | If life were discovered in the supposed ocean on Europa, it would be a popular destination for scientists and researchers. I am curious as to what life on Europa would be like, in terms of engineering and building a sustainable habitat.
First, to reach the ocean, is it more practical to melt down through the ice, or drill it? How hard would the ice be at 10km thick (in 1/9th of Earths gravity)
If melting/drilling a tunnel down to the ocean, would it be possible to passively leave this borehole open, or would the pressures cause the ice to flow together again? What kind of engineering would be required to keep the borehole open, assuming my colonists want an elevator to the surface... how would tunnels and rooms at the bottom of the ice behave, structurally?
If the ocean was reached, at about 10km depth, the water pressure would be close to 100bar with some rough calculations. Would it be practical to build habitats mounted on the underside of the ice, in the water, or would drilling rooms within the ice be easier? | 2016/09/26 | [
"https://worldbuilding.stackexchange.com/questions/56575",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/27754/"
] | It is much more practical to melt through ice than to drill through it. The most likely way of doing this is to place either radiothermalgenerators or a reactor on the front of your craft.
It would not be possible to keep the borehole open after passing through without installing a thick steel tube the full width and length of the tunnel. This would still snap as soon as the ice moved though (which might happen every Europan day due to tidal forces). [correction: Europa is tidally locked and thus has no days.]
My rough calculations suggest 133 bar, which is more or less what you got. This is roughly 3x greater pressure than modern large submarines are able to survive, so your pipe would have to be roughly 3 times stronger than a Seawolf pressure hull. That is a heck of a lot of material to cart across the solar system, and any flaw in its entire 10km length would result in collapse.
If it was absolutely necessary for your story, I would probably build the tunnel from some modern version of Pykrete. <https://en.wikipedia.org/wiki/Pykrete> Perhaps using a carbon nanotube fiber rather than cellulose (and ideally manufacturing the CNT on site). You would probably do best to situate the tunnel at a point which experiences the least ice movement. (Presumably far from any fault zone.)
Ice at the bottom of the hole would presumably not be very strong as it is under enough pressure that it is very close to becoming liquid again. You should transition away from Pykrete before reaching the water layer, and use some other material.
This whole endeavor is pretty unrealistic with any technology we are likely to have in the next 100 years though. (IMHO) By the time humans have the technology to do something like physically surviving a trip to the Europan ocean, they will have long since developed many technologies which would undermine the plot of this story, like very advanced genetic engineering which make humanity unrecognizable to readers, super tough nanobots who would have already scouted the Europan oceans quite thoroughly, and super advanced sensors which would have scanned the Europan oceans in detail right through the 10km of ice.
Also, it's likely that if life were discovered on Europa (especially macroscopic life) the entire moon would be utterly and completely off limits to human explorers for fear of contamination.
---
I just read JDługosz's answer and he makes a lot of good points that have made me rethink my answer.
Ok, the mass of the ice column that needs to be removed is M=density×height×π×r². Let's say the radius of the hole is 5 meters. Based on that I'm getting a mass of the column of 7.2E9 kg (neglecting the compressibility of ice). For the potential energy of raising those tailings to the surface I'm getting 11 MW years. (11 megawatts for 1 year). If your removal system is 50% efficient that would require a 22 MW (electrical) reactor, which is pretty serious hardware. At 35% efficiency, that would put out 64MW (thermal). Your boring machine is going to need more power to run the cutters, but I have no idea how to calculate this.
The energy needed to raise the temperature of the ice column to −50° C (which, from the phase diagram of water, appears to be the temperature needed to sublimate ice rapidly in a vacuum) is E = mass × specific heat × change in temperature. The specific heat of ice is roughly 2000 joules/kg°C. I'm getting a heat energy of 1.7E15 joules or 52 MW years (thermal).
The enthalpy of fusion of ice is 333KJ/KG. The enthalpy of vaporization of steam is 2257KJ/KG. I assume you just add these two together to get the enthalpy of sublimation? (I never did that in school.) That gives me a 1.86E16 joules to phase change the ice to steam or 589MW years, which is a really shockingly large number.
It also occurred to me after reading JDługosz's post that the sublimated ice would possibly recondense on the walls of the tunnel (although maybe not if the tunnel is in vacuum?) Regardless, the tunnel should probably be insulated in a melting scenario.
Regardless the vast majority of the energy need for the melting and vaporization plan goes into the boiling part of the phase change (rather than the melting part). This makes intuitive sense now that I think about it. Water quenching of hot things is crazily effective, and I once saw a TV show demonstrate that melting a hole through a glacier was way more efficient than drilling.
Based on these results, and taking into account the (probably) infeasibility of shoring up the tunnel, I would like to propose a new solution.
Covering the tunnel mouth with a lid to keep it pressurized to roughly 1 atmosphere. You still melt your way through the ice, but now you coat the interior of the ice tunnel with insulation rather than shoring. (Pykrete makes a great outer layer of insulation, but you would want something else on the inner layer.) Melted water stays liquid, meaning you don't have to spend energy boiling it off. This reduces the phase change energy requirements from 589MWY to 87MWY. Adding that to the temperature rise energy of 77MWY (you now need 0 degrees C, so this is a little higher than before) leaves you with 183MWY (thermal), which is still a heck of a lot of energy. I didn't even include the heat loss through the walls of the tunnel, but I think it's the least challenging part of the entire mission. Especially since the reactor needs no coolant radiators which, on a space ship in vacuum, would be enormous.
The weight of the water maintains more than enough pressure on the walls to keep them from collapsing. The reactor heat drills the hole without the need for thousands of tons of drilling equipment (and repair parts and machinery to let you install the repair parts) and ... billions (?) of tons of shoring.
Your explorers would need to live inside a super strong submarine which is 3 times stronger than a modern military submarine, but much less strong than the Alvin deep sea submersible. (The submarine would serve as an excellent space habitat by the way.) The reactor would need to be kept running permanently in order to prevent the column of water from refreezing, so you wouldn't just let it drop into the ocean once you broke through the ice. Probably the biggest challenge is now the mass of the insulation.
It would be really cool if there was a good way to manufacture cellulose (or other similarly performing polymer) from materials found on Europa. The ice on Europa is not 100% water. <http://people.virginia.edu/~rej/papers09/Carlson4019.pdf> Perhaps the ammonia and carbon dioxide ices can be used as feed stocks in a small factory to produce a hydrophilic polymer? The inner surface of the insulation might be a gel or a hydrate of some sort? You want something where most of the mass of the insulator is water, which is captured and held immobile. | when drilling/melting a hole in such a cold environment one important factor is time taken for the new ice layers to form. So the process should be as quickly as possible or we could figure out ways to prevent ice sheets from forming in a localized area.
>
> Ice forms When the water molecules move slowly because of low energy
> and it is easier for them to hook on to each other by sharing
> electrons. when salt is added salt molecules arrange themselves around
> the water molecules like little fences and keep the water molecules
> from hooking together. But if it gets cold enough, about 28.5 degrees
> Fahrenheit or -2 Celsius, ocean water will freeze too.
>
>
>
**source**: <http://quatr.us/chemistry/atoms/ice.htm>
So If we are able to build nano structures that can prevent water molecules from hooking easily while staying localized to that particular area and be degradable easily after sometime. Then we just have to put the nano material and wait without worrying of contaminating alien environment. There have been some research going in [this](http://www.livescience.com/8947-cool-tech-materials-prevent-ice-formation.html) area |
39,512 | On my Nexus 4, when I press the power button to access the lock screen (say, to check the time), the screen doesn't turn itself off for 30 seconds. This seems like an excessive delay. On my previous Froyo phone, the lock screen would time out in about 5 seconds. Is there an option to set the lock screen timeout? The only timeout-related settings I found are "Display -> Sleep" and "Security -> Automatically lock", but these don't seem to control what I want.
I could, of course, press the power button again to turn the screen off, but... laziness. | 2013/02/13 | [
"https://android.stackexchange.com/questions/39512",
"https://android.stackexchange.com",
"https://android.stackexchange.com/users/28347/"
] | You could watch out for an automation solution. I e.g. use [Tasker](https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm) for a lot of things like that (yeah, it's EUR 5 -- but you can obtain a free 7-day trial at the project page, and according to the dev even make it work another 7 days by exporting its settings, uninstall, reinstall, import settings). Rawly described: You combine events/conditions with tasks. In your case, you'd e.g. set the default timeout to 30s, and have Tasker take care for specialities:
* Profile "Reading":
+ **Condition:** App running (Browser, eBook-Reader, ... -- make your choices)
+ **Task:** Set screen timeout to 2min (automatically reverts when condition is no longer met)
* Profile "LockScreen":
+ **Condition**: [Screenlock On]
+ **Task:** Timeout 15s
You've got the idea. Unfortunately (as indicated by the square brackets), *Tasker* seems to have no condition for "Screenlock active" (or I did not find it), so this might require some addon (Locale addons are compatible). Nevertheless, you've got the idea -- and there are other automation solutions out there on the Playstore which might do the job to your liking, and even may be cheaper. I'd look out for addons, then check [Llama - Location Profiles](https://play.google.com/store/apps/details?id=com.kebab.Llama) etc. as well. | Actually there is a way to do just that in tasker,
basically you can simply set the screen timeout to 15secs once the screen turns off (which usually is the trigger to turn the lockscreen on :) )
and there also is an event which is called Display Unlocked (which is lockscreen unlocked)
and with that simply turn the screen timeout back to whatever u choose, i.e. 30 minutes. |
39,512 | On my Nexus 4, when I press the power button to access the lock screen (say, to check the time), the screen doesn't turn itself off for 30 seconds. This seems like an excessive delay. On my previous Froyo phone, the lock screen would time out in about 5 seconds. Is there an option to set the lock screen timeout? The only timeout-related settings I found are "Display -> Sleep" and "Security -> Automatically lock", but these don't seem to control what I want.
I could, of course, press the power button again to turn the screen off, but... laziness. | 2013/02/13 | [
"https://android.stackexchange.com/questions/39512",
"https://android.stackexchange.com",
"https://android.stackexchange.com/users/28347/"
] | You could watch out for an automation solution. I e.g. use [Tasker](https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm) for a lot of things like that (yeah, it's EUR 5 -- but you can obtain a free 7-day trial at the project page, and according to the dev even make it work another 7 days by exporting its settings, uninstall, reinstall, import settings). Rawly described: You combine events/conditions with tasks. In your case, you'd e.g. set the default timeout to 30s, and have Tasker take care for specialities:
* Profile "Reading":
+ **Condition:** App running (Browser, eBook-Reader, ... -- make your choices)
+ **Task:** Set screen timeout to 2min (automatically reverts when condition is no longer met)
* Profile "LockScreen":
+ **Condition**: [Screenlock On]
+ **Task:** Timeout 15s
You've got the idea. Unfortunately (as indicated by the square brackets), *Tasker* seems to have no condition for "Screenlock active" (or I did not find it), so this might require some addon (Locale addons are compatible). Nevertheless, you've got the idea -- and there are other automation solutions out there on the Playstore which might do the job to your liking, and even may be cheaper. I'd look out for addons, then check [Llama - Location Profiles](https://play.google.com/store/apps/details?id=com.kebab.Llama) etc. as well. | I just found a simple way to reduce the display timeout while on Lock Screen (in case you just want to wake the device, see what time it is, and then want it to lock itself more quickly than your android sleep timeout setting) :
Condition: SecureSettings - failed login attempts 1 and tick the "invert" box.
Action: Display timeout (put your desired seconds here).
This profile will detect the Lock Screen and *not* look for any failed attempt and will turn off the screen with your desired timeout.
Note that this condition requires [Secure Settings plugin](https://play.google.com/store/apps/details?id=com.intangibleobject.securesettings.plugin) to be installed. |
18,092 | What happens to Soyuz reentry capsules after landing?
I guess some must go to museums, but quite a lot of them have returned now.
Is there any indication of where and how they are stored? | 2016/09/07 | [
"https://space.stackexchange.com/questions/18092",
"https://space.stackexchange.com",
"https://space.stackexchange.com/users/6642/"
] | There were more than 500 Zenit (including Vostoks and Voskhods) landing capsules; an order of 160 (as of today) manned and unmanned Soyuz variants.
Plus prototypes used for modelling and testing on the ground.
That's a pretty large number of used capsules.
There are [65 pieces of equipment](http://militarynews.ru/story.asp?rid=2&nid=358592) certified for reuse in Soyuz TMA landing module. Such as cosmonaut seats or flight recorders.
There are radioactive pieces (gamma ray altimeter) and other dangerous or valuable pieces that are removed.
After that the shell is utilized one way or another.
Many go to museums.
**In general, [this image search](https://www.google.co.uk/search?q=%D1%81%D0%BF%D1%83%D1%81%D0%BA%D0%B0%D0%B5%D0%BC%D1%8B%D0%B9+%D0%B0%D0%BF%D0%BF%D0%B0%D1%80%D0%B0%D1%82+%D1%81%D0%BE%D1%8E%D0%B7+%D0%BC%D1%83%D0%B7%D0%B5%D0%B9&tbm=isch) should give you an idea.**
For example some are displayed in [RSC Energia in-house museum](http://nnm.me/blogs/krapich/muzey_rkk_energiya_im_s_p_koroleva/).
[](https://i.stack.imgur.com/I8KVj.jpg)
*photo from [krapich blog](http://nnm.me/blogs/krapich/muzey_rkk_energiya_im_s_p_koroleva/)*
Outside German Titov's museum:
[](https://i.stack.imgur.com/ZOec6.png)
*photo from [German Titov memorial museum](http://muzeytitova.ru/fond/veshchestvennye-istochniki/spuskaemyy-apparat-kosmicheskogo-korablya-soyuz-tma-21/)*
A piece of Prokopyevsk regional museum exhibition:
[](https://i.stack.imgur.com/T3LNK.jpg)
*photo from [Kemerovskaya oblats](http://kemoblast.ru/news/miners-day/2012/08/24/v-prokopevskom-kraevedcheskom-muzee-otkryt-novyj.html)*
A piece of Tsiolkovsky museum exhibition:
[](https://i.stack.imgur.com/MDmUM.jpg)
*photo from [Skorokhod blog](http://scorokhod.livejournal.com/70220.html)*
There is some amount stored on the [temporary storage pad](http://rsc-etestpilot.blogspot.ru/2012_07_01_archive.html) awaiting utilization.
[](https://i.stack.imgur.com/3YsDp.jpg)
*photo from [Mark Serov's blog](http://rsc-etestpilot.blogspot.ru/2012_07_01_archive.html)*
Another location we have photos of is probably the white brick building behind the temporary storage pad, but the author of the photos doesn't disclose the location. Not all of those have been into space. The the black-and-white, for example, seems to be a piece of testing equipment.
[](https://i.stack.imgur.com/oPafw.jpg)
*photo from [saoirse-2010 blog](http://saoirse-2010.livejournal.com/19823.html)* | Many are put on display, some just end in a junkyard
[Location of Russian Manned Spacecraft](http://www.astronautix.com/r/russialocatnedspacecraft.html) lists objects on display.
Edited quote from the [Soyuz spacecraft: post-landing and recovery](http://www.collectspace.com/ubb/Forum41/HTML/000169.html) post on Collectspace.com:
>
> Some of the spacecraft flown during Intercosmos missions are now on exhibit in the countries from where their international crew members hailed.
>
>
> - Soyuz 29, onboard which Sigmund Jähn flew, is at the Deutsches Museum für Meisterwerke der Naturwissenschaft and Technik (Deutsches Museum, for short) at Munich.
> - Miroslaw Hermaszewski's Soyuz 30 is in Warsaw, Poland.
>
> - Soyuz T-6, which launched Jean-Loup Chrétien, is on display at the Musee de l'Air near Paris (where the Paris Air Show is staged).
>
> - Soyuz TM-10 is at the National Air and Space Museum in Washington, DC. It was sold at Sotheby's in 1993 for $1.65 million to the Ross Perot Foundation, which in turn loaned it to the museum.
>
> - In 2000, Spacehab offered the Soyuz TM-26 descent module for direct sale, and then auctioned it through Superior Galleries. To my knowledge, it failed to meet its reserve.
>
>
> Unlike in the U.S., where the flown spacecraft are property of the government, the Soyuz belong to its manufacturer, RSC Energia. As such, the company's museum outside Moscow is probably the best place to see multiple Soyuz on display.
>
> The majority of the flown capsules are said to be kept in a Soyuz "junkyard" owned by Energia.
>
>
>
Another post at CollectSpace: [Russian Soyuz spacecraft on public display](http://www.collectspace.com/ubb/Forum31/HTML/000312.html) also contains some snippets of information.
I was unable to find information about that 'Energia junkyard', but look at this abandoned [Buran in ist construction hangar](http://www.dailymail.co.uk/sciencetech/article-3119861/Russia-s-forgotten-space-agency-Haunting-images-reveal-two-abandoned-Soviet-shuttles-rotting-giant-derelict-hangar.html) (photos by Ralph Mirebs)
[](https://i.stack.imgur.com/As8hc.jpg) |
74,106 | Is there any well written introduction for the modular space of complex structures on $T^2$? | 2011/08/30 | [
"https://mathoverflow.net/questions/74106",
"https://mathoverflow.net",
"https://mathoverflow.net/users/16750/"
] | As requested, I'm promoting this comment to an answer:
McKean and Moll's book "Elliptic curves" is a basic introduction to 2-tori with complex structure from the function theoretic, geometric, and arithmetic perspectives. What's closest to what you want is discussed in section 2.6 (on moduli of elliptic curves) and chapter 4 (on the modular group). | Serre's "A course in arithmetic" is quite nice for this and everything else it covers. |
18,928 | Is there a website or service that can quickly lookup how much bitcoins are there in a given wallet/address, so I can look up my own wallet from a friend's computer which doesn't have the Bitcoin client installed? | 2013/12/17 | [
"https://bitcoin.stackexchange.com/questions/18928",
"https://bitcoin.stackexchange.com",
"https://bitcoin.stackexchange.com/users/10925/"
] | You can use [Blockchain.info](http://blockchain.info).
Just paste the address you want to check into the Search inputbox and the website will show you all the transactions where that address was involved, as well as the balance. | In [Blockonomics](https://www.blockonomics.co) you can search multiple addresses of a wallet at once. It also has a [wallet watcher](https://www.blockonomics/blockonomics) where you can enter multiple addresses and get the overall balance in btc and currency of your choice. You can also see history of tx |
58,495 | When I was in Switzerland, the cooks prepared a special Swiss type of cheese and I've been wondering how this was called. It looks a bit like doner kebab(in the sense it is on a stick and they used some flame on it) and it smells a lot. Just in case this helps - this was in Zurich(the meal may be local for there).
Can anyone help me in pointing the name of that cheese(or maybe the meal name)? | 2015/06/24 | [
"https://cooking.stackexchange.com/questions/58495",
"https://cooking.stackexchange.com",
"https://cooking.stackexchange.com/users/36391/"
] | If I ignore the "on a spit" part I immediately think of [Raclette](https://en.m.wikipedia.org/wiki/Raclette), which is melted, roasted cheese served typically with bread or boiled potato.
* In household settings the cheese is often heated in small individual pans under a table-top broiler, each guest gets his or her own pan and prepares his food.
* Traditionally (and in larger settings) halved wheels of cheese are turned with the cut side towards a heat source and servings of molten cheese scratched off. The heating can be done either at a fireplace (embers) or on a special "machine" consisting of a heat source and a (often movable) tray for the cheese(s). The melting and serving is done by one [cook](http://www.hotelchatter.com/story/2011/1/28/15446/2441/hotels/The_Beverly_Wilshire's_Raclette_Nights_Will_Make_You_Melt) for all participants. In Switzerland, but also sometimes in neighbourung countries, traditional Raclette is sold on food fairs, [festivals](http://www.verbinet.com/events/raclette-cheese-festival) and markets. | Perhaps it was [raclette](https://en.wikipedia.org/?title=Raclette)? It is both the kind of cheese and a Swiss dish based on heating a hunk of cheese and scraping off ("racler") the melted part. The more known way to prepare raclette is on a table-top grill which is on the table. Often, other cheeses are used.
Sources:
<https://commons.wikimedia.org/wiki/File:Raclette_with_all_the_trimmings.jpg>
<https://commons.wikimedia.org/wiki/File:Raclette2.jpg> |
304,409 | There is a hat named **IDENTIFICATION DIVISION** which can be earned by earning a silver badge. The hat name is in **all caps**.
Is the naming in all caps purposefully, or is this a bug?
[](https://i.stack.imgur.com/9Z8mj.png) | 2017/12/13 | [
"https://meta.stackexchange.com/questions/304409",
"https://meta.stackexchange.com",
"https://meta.stackexchange.com/users/312043/"
] | [It's intentional](https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_73/rzasb/iddiv.htm) - it's a reference to COBOL, which [Admiral Grace Hopper](https://en.wikipedia.org/wiki/Grace_Hopper#COBOL) worked on. It's how the code would look.
Whoever came up with this needs additional stamps on their geek card. | Now we all luxuriate in encodings like UTF-16 and the frankly obese UTF-32, it's occasionally nice to travel back a generation or two and use text that can be encoded in DEC SIXBIT and perhaps even earlier.
This hat showcases such encodings.
Some programmers especially those using COBOL and even early FORTRAN dine out on this sort of thing.
Reference <https://en.wikipedia.org/wiki/Six-bit_character_code> |
457,547 | When I see a big radio antenna, I like to imagine it's a giant incandescent light bulb filament in the vertical, but of a invisible light. So that it "glows" the radio, performing oscillations which contains all the music/voice information.
But at the reverse, is it possible to create a practical experiment which modulates (or something) an analog audio signal and transmits it by glowing some sort of light, then have a antenna or sensor to pick it up and reproduce the signal to a speaker?
Is it possible to use a mono pole antenna to detect light? | 2019/01/29 | [
"https://physics.stackexchange.com/questions/457547",
"https://physics.stackexchange.com",
"https://physics.stackexchange.com/users/221298/"
] | >
> But at the reverse, is it possible to create a practical experiment which modulates (or something) an analog audio signal and transmits it by glowing some sort of light, then have a antenna or sensor to pick it up and reproduce the signal to a speaker?
>
>
>
Yes, in principle.
Analog modulation of optical signals is not super common, but it is done, for example in many CATV-over-optical-fiber systems.
Free-space optical communication is commonly be done between a hand-held remote control and a television set.
Optical communication of audio signals is done in TOSLINK interconnect.
There's no technological reason these things aren't all combined into a single analog, free-space, audio communication system, only economic reasons: We have cheaper ways of doing it so nobody has bothered to commercialize such a thing.
It would be pretty easy to set up a class-room demonstration where an audio signal is sent to an LED, which illuminates a photodiode a few cm away, which connects through an amplifier to drive a speaker, if you wanted to demonstrate such a thing.
Even with much older technology, there was the [photophone](https://en.wikipedia.org/wiki/Photophone) developed by Alexander Graham Bell. | Various spy agencies have used this technique to eavesdrop on conversations from some distance away. When people are talking inside a room that has windows, there is a very tiny vibration of the windows as the sound waves from the voices bounce off of those windows. It is possible to reflect a laser beam off of a vibrating window, receive the reflected beam, and recover the sound waves from the modulation contained in that beam. |
1,335,616 | I'd like word completion to show all matching type names (not only those in imported namespaces). If nampespace of that type is not imported - it should be imported as I choose the type from list, and if that type was in the non-referenced assembly - that assembly should be added to project references (adding imports and references - after prompt, of course)
Trying to recollect exact type name and it's namespace is real pain sometimes.
Is there any product with such completion?
(Yes, I know about Resharper. No, it doesn't support this)
PS and it would be really great, if word completion could show all types having text anywhere in the name - not only in the beginning. For example, I type "writer" - and completion shows me all writers (TextWriter, StringWriter, StreamWriter - etc) | 2009/08/26 | [
"https://Stackoverflow.com/questions/1335616",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/162636/"
] | You should take a look at ReSharper (Again) it does support the functionality with part of a type name or only writing the capital letters of a camel case type name e.g. SomeType can be found with ST.
The number of assemblies any tool will look in for possible types will *always* be limited. After all unless you tell the tool about the assemblies (tell in some way as in registering an assembly in the GAC, referencing it or any other means) the tool will simply not know of that assembly at will therfor not search it. On top of that you really do not want the tool to search through to many assemblies since you'd then risk being done writing the full name of any type before the tool will be done searching | What you are looking for is c# reshaper.
Just type something in like MD and press Ctrl+Space it will bring up every standard include. Just press space to confirm(in this case MD5 will show up). It also learns what you use most. |
1,335,616 | I'd like word completion to show all matching type names (not only those in imported namespaces). If nampespace of that type is not imported - it should be imported as I choose the type from list, and if that type was in the non-referenced assembly - that assembly should be added to project references (adding imports and references - after prompt, of course)
Trying to recollect exact type name and it's namespace is real pain sometimes.
Is there any product with such completion?
(Yes, I know about Resharper. No, it doesn't support this)
PS and it would be really great, if word completion could show all types having text anywhere in the name - not only in the beginning. For example, I type "writer" - and completion shows me all writers (TextWriter, StringWriter, StreamWriter - etc) | 2009/08/26 | [
"https://Stackoverflow.com/questions/1335616",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/162636/"
] | You should take a look at ReSharper (Again) it does support the functionality with part of a type name or only writing the capital letters of a camel case type name e.g. SomeType can be found with ST.
The number of assemblies any tool will look in for possible types will *always* be limited. After all unless you tell the tool about the assemblies (tell in some way as in registering an assembly in the GAC, referencing it or any other means) the tool will simply not know of that assembly at will therfor not search it. On top of that you really do not want the tool to search through to many assemblies since you'd then risk being done writing the full name of any type before the tool will be done searching | In addition to Resharper, [CodeRush](http://www.devexpress.com/Products/Visual_Studio_Add-in/index.xml) also has this feature. The [free version](http://www.devexpress.com/Products/Visual_Studio_Add-in/CodeRushX/) probably does too. |
1,335,616 | I'd like word completion to show all matching type names (not only those in imported namespaces). If nampespace of that type is not imported - it should be imported as I choose the type from list, and if that type was in the non-referenced assembly - that assembly should be added to project references (adding imports and references - after prompt, of course)
Trying to recollect exact type name and it's namespace is real pain sometimes.
Is there any product with such completion?
(Yes, I know about Resharper. No, it doesn't support this)
PS and it would be really great, if word completion could show all types having text anywhere in the name - not only in the beginning. For example, I type "writer" - and completion shows me all writers (TextWriter, StringWriter, StreamWriter - etc) | 2009/08/26 | [
"https://Stackoverflow.com/questions/1335616",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/162636/"
] | Right or wrong, the goal of intellisense is to provide legal completions for the current edit positions. This is by no means 100% accurate but we do strive for listing only valid completions.
Showing type names which are not imported and/or not a type in the assembly the current project references flies in the face of this approach. It is instead suggesting code that is known to be illegal to the user.
True we could then go back and fix this up by adding an assembly reference. But some users may find this very annoying. They are typing up code and suddenly references are added and their imports are changed.
I'm not saying this is necessarily a bad feature, just that it goes against the current design philosophy and has the potential to upset a good portion of users. | What you are looking for is c# reshaper.
Just type something in like MD and press Ctrl+Space it will bring up every standard include. Just press space to confirm(in this case MD5 will show up). It also learns what you use most. |
1,335,616 | I'd like word completion to show all matching type names (not only those in imported namespaces). If nampespace of that type is not imported - it should be imported as I choose the type from list, and if that type was in the non-referenced assembly - that assembly should be added to project references (adding imports and references - after prompt, of course)
Trying to recollect exact type name and it's namespace is real pain sometimes.
Is there any product with such completion?
(Yes, I know about Resharper. No, it doesn't support this)
PS and it would be really great, if word completion could show all types having text anywhere in the name - not only in the beginning. For example, I type "writer" - and completion shows me all writers (TextWriter, StringWriter, StreamWriter - etc) | 2009/08/26 | [
"https://Stackoverflow.com/questions/1335616",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/162636/"
] | Right or wrong, the goal of intellisense is to provide legal completions for the current edit positions. This is by no means 100% accurate but we do strive for listing only valid completions.
Showing type names which are not imported and/or not a type in the assembly the current project references flies in the face of this approach. It is instead suggesting code that is known to be illegal to the user.
True we could then go back and fix this up by adding an assembly reference. But some users may find this very annoying. They are typing up code and suddenly references are added and their imports are changed.
I'm not saying this is necessarily a bad feature, just that it goes against the current design philosophy and has the potential to upset a good portion of users. | In addition to Resharper, [CodeRush](http://www.devexpress.com/Products/Visual_Studio_Add-in/index.xml) also has this feature. The [free version](http://www.devexpress.com/Products/Visual_Studio_Add-in/CodeRushX/) probably does too. |
114,406 | I am traveling to LAX, and I thought about flying from Dublin, because it has a preclearance station.
This station will give me an immigration and customs clearance, so when I arrive at LAX, I will just exit the plane like I was a citizen (don't have to go through CBP check anymore).
To go to preclearance, I have to have an already purchased ticket to LAX from Dublin.
Now I have purchased a ticket that flies from Dublin through Amsterdam (Netherlands) to LAX.
Question:
1. If I am precleared to enter the US (without an immigration check at LAX upon arrival), how will they know that I have been precleared, and they have to treat me differently from other passengers who are not precleared?
2. Upon arrival at LAX, there are two kinds of lanes, one for US citizens (and permanent residents), and another lane for non-permanent residents. Now normally I would go to the non-permanent resident lane and would have to go through CBP check. But in this case being precleared, will i be able to enter the citizen lane? | 2018/05/06 | [
"https://travel.stackexchange.com/questions/114406",
"https://travel.stackexchange.com",
"https://travel.stackexchange.com/users/77389/"
] | Airplanes are pre-cleared, not humans
-------------------------------------
What happens with pre-clearance is the airplane docks in an area that is under control of US CBP or trusted partners. The airplane is inspected (cleared), then each passenger and their possessions enters this area and effectively is landed in the USA, with immigration done on them, and customs done on their stuff. All is loaded on the airplane, doors shut, US Customs seals slapped on all the doors (not really), and the plane is watched to make sure it doesn't stop in a ramp area to have any cargo or passengers added.
As long as it flies uneventfully to the US, CBP doesn't care where it unloads, and you will not be talking to CBP again (or, anyone). Forget citizen gates, there won't be any gates at all. It may dock at a domestic gate so onward pax don't have to re-clear security. In an emergency it could also divert to a domestic municipal airport like SHD that has no CBP presence, and that's not going to create a serious customs/immigration problem. **Imagine you legally entered the US when you set foot on that plane**.
This only works if you board a plane that is pre-cleared.
So you see where your plan falls apart. US CBP in Ireland isn't in the business of pre-clearing flights to Amsterdam.
Redesign your journey so your leg which first lands in the US starts in a pre-clearance airport.
By the way, the Irish [have a delightful video](https://www.dublinairport.com/at-the-airport/passenger-Information/us-preclearance-facility) about it. They seem to be really proud to have a US CBP presence, and they slap an American flag on one of their terminals, almost as if it's US territory! At a certain point, your flight is called for prescreening and you are directed to the TSA area. You scan your documents at a kiosk, then bring your papers to a CBP officer who checks your papers and asks any questions. | "like a citizen" should read "as if I were arriving from another US airport" because citizenship has nothing to do with whether a passenger must clear immigration and customs. Only the point of origin is relevant.
You cannot use preclearance if you're flying through Amsterdam because this statement is incomplete:
>
> To go to preclearance, I have to have an already purchased ticket to LAX from Dublin.
>
>
>
It should actually say
>
> To go to preclearance, I have to have an already purchased *direct* ticket to the United States from Dublin.
>
>
>
The problems you're asking about do not exist because preclearance applies only to direct flights. Either all the people and goods on the plane have been cleared, or none of them have. But your questions are a good illustration of why preclearance is only allowed on direct flights:
>
> If I am precleared to enter the US (without an immigration check at LAX upon arrival), how will they know that I have been precleared, and they have to treat me differently from other passengers who are not precleared?
>
>
>
There's no way for them to know that, which is why the entire plane must be precleared, or none of it. Some precleared planes even land in airports like New York's La Guardia, where CBP does not process international commercial flights. The first awareness I ever had that preclearance exists came when I noticed an Air Canada flight at La Guardia.
>
> Upon arrival at LAX, there are two kinds of lanes, one for US citizens (and permanent residents), and another lane for non-permanent residents. Now normally I would go to the non-permanent resident lane and would have to go through CBP check. But in this case being pre-cleared, will i be able to enter the citizen lane?
>
>
>
This points out another inconsistency in your thinking: a pre-cleared foreigner is not in the same category as a non-cleared US citizen. The latter must present a passport to a passport inspector, while the former has already done so. |
114,406 | I am traveling to LAX, and I thought about flying from Dublin, because it has a preclearance station.
This station will give me an immigration and customs clearance, so when I arrive at LAX, I will just exit the plane like I was a citizen (don't have to go through CBP check anymore).
To go to preclearance, I have to have an already purchased ticket to LAX from Dublin.
Now I have purchased a ticket that flies from Dublin through Amsterdam (Netherlands) to LAX.
Question:
1. If I am precleared to enter the US (without an immigration check at LAX upon arrival), how will they know that I have been precleared, and they have to treat me differently from other passengers who are not precleared?
2. Upon arrival at LAX, there are two kinds of lanes, one for US citizens (and permanent residents), and another lane for non-permanent residents. Now normally I would go to the non-permanent resident lane and would have to go through CBP check. But in this case being precleared, will i be able to enter the citizen lane? | 2018/05/06 | [
"https://travel.stackexchange.com/questions/114406",
"https://travel.stackexchange.com",
"https://travel.stackexchange.com/users/77389/"
] | "like a citizen" should read "as if I were arriving from another US airport" because citizenship has nothing to do with whether a passenger must clear immigration and customs. Only the point of origin is relevant.
You cannot use preclearance if you're flying through Amsterdam because this statement is incomplete:
>
> To go to preclearance, I have to have an already purchased ticket to LAX from Dublin.
>
>
>
It should actually say
>
> To go to preclearance, I have to have an already purchased *direct* ticket to the United States from Dublin.
>
>
>
The problems you're asking about do not exist because preclearance applies only to direct flights. Either all the people and goods on the plane have been cleared, or none of them have. But your questions are a good illustration of why preclearance is only allowed on direct flights:
>
> If I am precleared to enter the US (without an immigration check at LAX upon arrival), how will they know that I have been precleared, and they have to treat me differently from other passengers who are not precleared?
>
>
>
There's no way for them to know that, which is why the entire plane must be precleared, or none of it. Some precleared planes even land in airports like New York's La Guardia, where CBP does not process international commercial flights. The first awareness I ever had that preclearance exists came when I noticed an Air Canada flight at La Guardia.
>
> Upon arrival at LAX, there are two kinds of lanes, one for US citizens (and permanent residents), and another lane for non-permanent residents. Now normally I would go to the non-permanent resident lane and would have to go through CBP check. But in this case being pre-cleared, will i be able to enter the citizen lane?
>
>
>
This points out another inconsistency in your thinking: a pre-cleared foreigner is not in the same category as a non-cleared US citizen. The latter must present a passport to a passport inspector, while the former has already done so. | Other answers are correct, but to be concise: Preclearance is not a service that passengers may *choose* to use, by having *purchased a ticket* to the United States. Rather, pre-clearance is *part of the pre-boarding procedure*, precisely for passengers boarding *direct flights to the United States* from designated pre-clearance facilities. Since all people on such flights (and their baggage) will have been admitted to the United States before boarding, they are generally not subject to border inspection at all when arriving in the United States - the flight is treated as if it is arriving from within the United States.
[Airports with Preclearance facilities are listed here](https://www.cbp.gov/border-security/ports-entry/operations/preclearance), and the vast majority of direct flights from those airports to the United States will use the preclearance facilities.
However, even from a departure airport with preclearance facilities, preclearance may sometimes not be employed; passengers on a flight not precleared will then pass through immigration and customs upon arrival in the US. |
114,406 | I am traveling to LAX, and I thought about flying from Dublin, because it has a preclearance station.
This station will give me an immigration and customs clearance, so when I arrive at LAX, I will just exit the plane like I was a citizen (don't have to go through CBP check anymore).
To go to preclearance, I have to have an already purchased ticket to LAX from Dublin.
Now I have purchased a ticket that flies from Dublin through Amsterdam (Netherlands) to LAX.
Question:
1. If I am precleared to enter the US (without an immigration check at LAX upon arrival), how will they know that I have been precleared, and they have to treat me differently from other passengers who are not precleared?
2. Upon arrival at LAX, there are two kinds of lanes, one for US citizens (and permanent residents), and another lane for non-permanent residents. Now normally I would go to the non-permanent resident lane and would have to go through CBP check. But in this case being precleared, will i be able to enter the citizen lane? | 2018/05/06 | [
"https://travel.stackexchange.com/questions/114406",
"https://travel.stackexchange.com",
"https://travel.stackexchange.com/users/77389/"
] | Airplanes are pre-cleared, not humans
-------------------------------------
What happens with pre-clearance is the airplane docks in an area that is under control of US CBP or trusted partners. The airplane is inspected (cleared), then each passenger and their possessions enters this area and effectively is landed in the USA, with immigration done on them, and customs done on their stuff. All is loaded on the airplane, doors shut, US Customs seals slapped on all the doors (not really), and the plane is watched to make sure it doesn't stop in a ramp area to have any cargo or passengers added.
As long as it flies uneventfully to the US, CBP doesn't care where it unloads, and you will not be talking to CBP again (or, anyone). Forget citizen gates, there won't be any gates at all. It may dock at a domestic gate so onward pax don't have to re-clear security. In an emergency it could also divert to a domestic municipal airport like SHD that has no CBP presence, and that's not going to create a serious customs/immigration problem. **Imagine you legally entered the US when you set foot on that plane**.
This only works if you board a plane that is pre-cleared.
So you see where your plan falls apart. US CBP in Ireland isn't in the business of pre-clearing flights to Amsterdam.
Redesign your journey so your leg which first lands in the US starts in a pre-clearance airport.
By the way, the Irish [have a delightful video](https://www.dublinairport.com/at-the-airport/passenger-Information/us-preclearance-facility) about it. They seem to be really proud to have a US CBP presence, and they slap an American flag on one of their terminals, almost as if it's US territory! At a certain point, your flight is called for prescreening and you are directed to the TSA area. You scan your documents at a kiosk, then bring your papers to a CBP officer who checks your papers and asks any questions. | Other answers are correct, but to be concise: Preclearance is not a service that passengers may *choose* to use, by having *purchased a ticket* to the United States. Rather, pre-clearance is *part of the pre-boarding procedure*, precisely for passengers boarding *direct flights to the United States* from designated pre-clearance facilities. Since all people on such flights (and their baggage) will have been admitted to the United States before boarding, they are generally not subject to border inspection at all when arriving in the United States - the flight is treated as if it is arriving from within the United States.
[Airports with Preclearance facilities are listed here](https://www.cbp.gov/border-security/ports-entry/operations/preclearance), and the vast majority of direct flights from those airports to the United States will use the preclearance facilities.
However, even from a departure airport with preclearance facilities, preclearance may sometimes not be employed; passengers on a flight not precleared will then pass through immigration and customs upon arrival in the US. |
252,416 | Currently on stackoverflow.com, there are 275 questions tagged [android-intent](https://stackoverflow.com/questions/tagged/android-intent "show questions tagged 'android-intent'"), and 910 questions tagged [intent](https://stackoverflow.com/questions/tagged/intent "show questions tagged 'intent'"). Of the 'intent' tagged questions, only one is not about Android intents, and it is legitimately about another technology of the same name.
[Fortran intent(inout) versus omitting intent](https://stackoverflow.com/questions/2880537/fortran-intentinout-vs-no-intent)
Since the term 'android-intent' is arguably less ambiguous than 'intent', even though more than 99% of questions tagged 'intent' are about Android intents, and since more than one technology shares this name, I propose retagging the 909 Android 'intent' questions as 'android-intent'.
If someone with permission to do this disagrees, then please at least change 'android-intent' tags to 'intent'. | 2011/05/29 | [
"https://meta.stackoverflow.com/questions/252416",
"https://meta.stackoverflow.com",
"https://meta.stackoverflow.com/users/750987/"
] | I think it would probably be better to make [intent](https://stackoverflow.com/questions/tagged/intent "show questions tagged 'intent'") be a synonym for [android-intent](https://stackoverflow.com/questions/tagged/android-intent "show questions tagged 'android-intent'"), as the latter is less ambiguous to the reader, there's no difference as far as the search engines are concerned, and that makes it possible for [intent](https://stackoverflow.com/questions/tagged/intent "show questions tagged 'intent'") to be used for something else in the future without a major retagging exercise.
Oh, and write a good tag wiki (or at least an excerpt) once the merge is done, please! Help to educate those of us (like me!) who know nothing about the technology being identified… | Shouldn't you just tag those questions with [android](https://stackoverflow.com/questions/tagged/android "show questions tagged 'android'") and [intent](https://stackoverflow.com/questions/tagged/intent "show questions tagged 'intent'")? |
339,281 | I am trying to create an upload control for ASP.NET MVC with jQuery progress bar. In ASP.NET the implementation works no problems, but in MVC the problem is that the server doesn't respond to my callbacks until the file is uploaded.
The upload control is based on html file upload element, and I cannot for the life of me, understand how MVC handles postback + callback synchronously ?
I have searched for a whole bunch of answers, but **all I can find is a "callback+callback" solution and NOT a postback+callback.**
Does anyone have any idea how to solve this problem for MVC ?
Thanks | 2008/12/04 | [
"https://Stackoverflow.com/questions/339281",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/-1/"
] | Hrmmm,
Thomas, MVC does not handle post-backs at all. Because a URL is directly routed to an Action method on a controller, a form is not meant to actually post-back to itself. Further more, all of the post back processing that Asp.Net had to handle post-backs on the server was pulled out of the .Net MVC framework.
A better approach to accomplish what you're trying to do with a progress bar would be to use JQuery with AJAX to make the call to your server and then use Javascript/CSS (possibly a lightbox approach) or a pop-up window to inform the user that they are waiting. When the Ajax call completes it's work, you can have Javascript fire the redirect to the page in your MVC that you want the user to be redirected to after the action has been performed. Making AJAX calls with JQuery is a total breeze and is pretty fun to play around with as well!
[Check it...](http://www.ajaxprojects.com/ajax/tutorialdetails.php?itemid=293) | Suggestion:
>
> You can use the [JQuery Uploadify control](http://www.uploadify.com/) to show the status of
> the upload. This control has a flash and html 5 type controls. Use whichever is applicable to you.
>
>
> |
61,921,792 | I've been studying python for data science for about 5 months now. But I get really stucked when it comes to matplotlib. There's always so many options to do anything, and I can't see a well defined path to do anything. Does anyone have this problem too and knows how to deal with it? | 2020/05/20 | [
"https://Stackoverflow.com/questions/61921792",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/13584634/"
] | I had the same problem sometime back. I just picked the Boston Housing Prices dataset and kept practicing on that. If you work on it enough you will be able to create all types of plots for the EDA and get good practice. Of course after a certain point it can get boring , thats when you jump to a dataset in an area of your interests, in my case it was movie reviews.
Below is the link to the housing prices data.
<https://www.kaggle.com/c/house-prices-advanced-regression-techniques> | I think your question is stating that you are bored and do not have any projects to make. If that is correct, there are many datasets available on sites like Kaggle that have open-source datasets for practice programmers. |
61,921,792 | I've been studying python for data science for about 5 months now. But I get really stucked when it comes to matplotlib. There's always so many options to do anything, and I can't see a well defined path to do anything. Does anyone have this problem too and knows how to deal with it? | 2020/05/20 | [
"https://Stackoverflow.com/questions/61921792",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/13584634/"
] | I had the same problem sometime back. I just picked the Boston Housing Prices dataset and kept practicing on that. If you work on it enough you will be able to create all types of plots for the EDA and get good practice. Of course after a certain point it can get boring , thats when you jump to a dataset in an area of your interests, in my case it was movie reviews.
Below is the link to the housing prices data.
<https://www.kaggle.com/c/house-prices-advanced-regression-techniques> | in programming in general " There's always so many options to do anything".
i recommend to you that read library and understand their functions and classes in a glance, then go and solve some problems from websites or give a real project if you can. if your code works do not worry and go ahead.
after these try and error you have a lot of real idea about various problems and you recognize difference between these options and pros and cons of them. like me three years ago. |
78,273 | [This transaction](https://www.blockchain.com/btc/tx/7253e818ba712f98654ca1fc03191027e590dcac06eda36e7b13dc835422b67a?show_adv=true) is from one of the latest block. However I don't understand why it seems to be just dividing a single transaction without being spent and transferred to someone else. | 2018/08/16 | [
"https://bitcoin.stackexchange.com/questions/78273",
"https://bitcoin.stackexchange.com",
"https://bitcoin.stackexchange.com/users/86479/"
] | To elaborate on my comment,
I think that any type of 'reward' will have a monetary value, whether that be indirect or not. Proposing to reward miners with something like 'faster transaction confirmation' (the example in your comment) would only add friction to their ability to reap financial reward. A savvy miner could expand their mining infrastructure, to gain a ton of quick confirmation credits. With that done, they could then sell faster confirmations to other users, and presumably profit in doing so.
I think that adding friction in this way is bad, it introduces external factors (the ability of a miner to network and sell their fast confirmation) that will affect the profitability of individual miners differently. Having an explicit monetary reward (ie the bitcoin block reward) keeps friction low: all miners that find a block will are equally capable of claiming its reward.
As I wrote above, **If the reward is something to be sought after, then it will have value, even if indirectly.**
There is no known way to create a secure cryptocurrency network without cost. POW requires energy expenditure, POS requires users to lock up their funds (opportunity costs), etc. Relying on users to pay these costs without reward makes for broken game theory, and a broken/insecure network. | >
> it is crucial to incentivize miners by monetary reward, because mining
> process has significant monetary cost (energy/electricity cost). ?
> otherwise, mining process is not affordable for miners ?
>
>
>
This was not the specific reason for a block reward. The [whitepaper](https://bitcoin.org/bitcoin.pdf) states:
>
> This adds an incentive for nodes to support the network, and provides
> a way to initially distribute coins into circulation, since there is
> no central authority to issue them.
>
>
>
1. **The need to secure the blockchain** (with proof of work). Maybe in an ideal world miners would mine just to secure the network, and everyone would feel the value was worth the cost.
2. **A controlled supply of Bitcoin with a minting process**. You could premine all of the coins, but who gets the coins? Mining is a fair way of distributing coins by rewarding those who do work (in the form of hashpower).
Proof of Work
-------------
In order to establish a consensus mechanism nodes agree to validate blocks with a minimum proof of work (energy used, money spent).
**Proof of Work** can be also thought of as **proof of energy spent**. In physics:
>
> Work transfers energy from one place to another, or one form to
> another.
>
>
>
In this case, the energy is transferred from electricity to a mechanism for ***consensus***, and ***security of funds***. Without the work, you don't have consensus or security. |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | 2 ideas:
Instead of thinking of the square as a closed box, take the top away and allow the circles to fall under the effects of gravity into the open box. By altering the position of the circles before they fall you create randomness. This might be the same or similar to your billards example.
or
Use [Quadtrees](http://en.wikipedia.org/wiki/Quadtree "Quadtrees") to divide up the space in the box and place randomly checking for overlap using collision detection, which in this case might only need to be the center of the circle to another center is greater than double the radius and the walls of the box are greater than a radius away. By using quadtrees this will make the algorithm more efficient. | Maybe you can find a geometrical property that is true only for 200-packings and not for 199-or-less-packings. Then build the packing incrementally while conserving the property.
For example, you may examine several available 200-packings and measure the maximal distance between all circle centers -- *m*. Then construct a packing incrementally, preserving *m*.
I don't know how often such a construction succeeds, but you can add more invariant properties as you wish to increase the chance of success. |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | Start by using the [basic algorithm](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force/6002708#6002708) to draw as many as possible circles that don't collide. When it finishes (and it can't reach 200 circles), start pushing in circles. I mean physically push them in with a physics engine:
<http://www.sgtconker.com/2010/09/article-xna-farseer-platform-physics-tutorial/> (without using gravity). | Maybe you can find a geometrical property that is true only for 200-packings and not for 199-or-less-packings. Then build the packing incrementally while conserving the property.
For example, you may examine several available 200-packings and measure the maximal distance between all circle centers -- *m*. Then construct a packing incrementally, preserving *m*.
I don't know how often such a construction succeeds, but you can add more invariant properties as you wish to increase the chance of success. |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | Start by using the [basic algorithm](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force/6002708#6002708) to draw as many as possible circles that don't collide. When it finishes (and it can't reach 200 circles), start pushing in circles. I mean physically push them in with a physics engine:
<http://www.sgtconker.com/2010/09/article-xna-farseer-platform-physics-tutorial/> (without using gravity). | 2 ideas:
Instead of thinking of the square as a closed box, take the top away and allow the circles to fall under the effects of gravity into the open box. By altering the position of the circles before they fall you create randomness. This might be the same or similar to your billards example.
or
Use [Quadtrees](http://en.wikipedia.org/wiki/Quadtree "Quadtrees") to divide up the space in the box and place randomly checking for overlap using collision detection, which in this case might only need to be the center of the circle to another center is greater than double the radius and the walls of the box are greater than a radius away. By using quadtrees this will make the algorithm more efficient. |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | 2 ideas:
Instead of thinking of the square as a closed box, take the top away and allow the circles to fall under the effects of gravity into the open box. By altering the position of the circles before they fall you create randomness. This might be the same or similar to your billards example.
or
Use [Quadtrees](http://en.wikipedia.org/wiki/Quadtree "Quadtrees") to divide up the space in the box and place randomly checking for overlap using collision detection, which in this case might only need to be the center of the circle to another center is greater than double the radius and the walls of the box are greater than a radius away. By using quadtrees this will make the algorithm more efficient. | If you'll sometimes have a high number of circles such that you are close to, or at, maximal packing, the best solution is to start with your circles maximally packed in some corner (which I guess is hexagonal packing) and then do a physical simulation where you add some "temperature", i.e. you randomly kick some circles and let them collide for some finite time.
I am afraid that with the other methods you might never be able to fit all your circles if you have so many circles that any valid solution would be close to maximal packing. |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | 2 ideas:
Instead of thinking of the square as a closed box, take the top away and allow the circles to fall under the effects of gravity into the open box. By altering the position of the circles before they fall you create randomness. This might be the same or similar to your billards example.
or
Use [Quadtrees](http://en.wikipedia.org/wiki/Quadtree "Quadtrees") to divide up the space in the box and place randomly checking for overlap using collision detection, which in this case might only need to be the center of the circle to another center is greater than double the radius and the walls of the box are greater than a radius away. By using quadtrees this will make the algorithm more efficient. | Suppose you want n = 200 circles. My suggestion is to pick a number moderately larger than n, say m = 300, and generate that many points at random locations within the square. This set of m points is your *candidate set* of circle centres. Now produce a graph containing m vertices, one for each point, in which two vertices are linked by an edge if and only if the distance between their points is less than the circle diameter -- it is exactly in this situation that we would be forbidden to include *both* circles in the solution, because they would overlap.
You can now model the problem of choosing which candidate circle centres should actually become circles as a [maximum independent set problem](http://en.wikipedia.org/wiki/Independent_set_%28graph_theory%29): find a maximum-sized set of vertices in this graph having the property that no two vertices in the set are linked by an edge. This will find a set of circle centres such that no two of their circles would overlap. If this set contains more than n circles, then discard a random selection of circles until just n remain. If fewer than n circles are found, you'll need to increase m and try again.
Unfortunately the maximum independent set problem is NP-hard, so I don't know whether it will be feasible to solve on a 300-vertex graph. (And in turn, I don't know whether 300 random centres will give you enough flexibility to find 200 non-overlapping circles...) But in any case, you would normally solve maximum independent set in one of two ways:
1. Look for a [minimum vertex cover](http://en.wikipedia.org/wiki/Vertex_cover), then take every *other* vertex to be the maximum independent set
2. Produce the complement graph (i.e. the graph in which two vertices are linked by an edge if and only if they are *not* linked by an edge in the original graph), and then find a [maximum clique](http://en.wikipedia.org/wiki/Clique_%28graph_theory%29) in this graph
Those Wikipedia pages contain links to papers describing algorithms for these problems that, while still exponential-time, are much faster than a standard "full backtracking" algorithm. A couple of things to bear in mind:
* You don't actually need the provably maximum independent set, just one >= n. So heuristics may be just fine; note the particularly simple heuristic for minimum vertex cover on the Wikipedia page.
* Beware the difference between "maximal" (easy) and "maximum" (hard) cliques/covers/independent sets! |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | 2 ideas:
Instead of thinking of the square as a closed box, take the top away and allow the circles to fall under the effects of gravity into the open box. By altering the position of the circles before they fall you create randomness. This might be the same or similar to your billards example.
or
Use [Quadtrees](http://en.wikipedia.org/wiki/Quadtree "Quadtrees") to divide up the space in the box and place randomly checking for overlap using collision detection, which in this case might only need to be the center of the circle to another center is greater than double the radius and the walls of the box are greater than a radius away. By using quadtrees this will make the algorithm more efficient. | @toto2 @cyborg @TokenMacGuy
Update:
I have implemented the **billard solution** with the FarseerPhysicsEngine and played around with it a bit. Within the process of implementing the solution I modified the problem a bit :): Instead of keeping all circles inside the box, I allow the circles to move outside the border and let the outside part reappear on the opposite side (pretty much like in the oldschool asteroids game). This makes my distribution suitable for infinite repetition in x and y direction, which is even better for the underlying Finite Element modelling task. This comes along with some other issues regarding the physics simulation, and as this was not part of the original question, I will only describe those, if anyone is particularly interested.
So **what I did**: I order as many circles as wanted or as fit in the most dense order possible (where the centres of the circles are in a hexagon order). I leave a margin around the circles to make the simulation more stable. It sometimes happens, that circles overlap otherwise. Every circle gets a random velocity vector and mass. Everything else is collision detection and handling, done by the physics engine.
The **outcome**: It works well for high amounts of circles.
If performed with a small number of circles, they tend to stick together. I cant really explain why. Might be that Fraseer doesn't model the collision as ideally elastic, so that energy is dissipated. I don't know whether, and if where, there is a property for that. As I set friction to zero for the movement, this could lead to this kind of clustering:
Anyway, I am quite happy with the result for many circles and - as this was the unsolved part so far, I suppose this will do. It's a shame, that I don't have the time to dig deeper into the other concepts, although I will for sure have a deeper look at them later on.
Thank you all for participating!! Was fun to get all your input! If you have further ideas or comments on the solution, please let me know. |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | Start by using the [basic algorithm](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force/6002708#6002708) to draw as many as possible circles that don't collide. When it finishes (and it can't reach 200 circles), start pushing in circles. I mean physically push them in with a physics engine:
<http://www.sgtconker.com/2010/09/article-xna-farseer-platform-physics-tutorial/> (without using gravity). | If you'll sometimes have a high number of circles such that you are close to, or at, maximal packing, the best solution is to start with your circles maximally packed in some corner (which I guess is hexagonal packing) and then do a physical simulation where you add some "temperature", i.e. you randomly kick some circles and let them collide for some finite time.
I am afraid that with the other methods you might never be able to fit all your circles if you have so many circles that any valid solution would be close to maximal packing. |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | Start by using the [basic algorithm](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force/6002708#6002708) to draw as many as possible circles that don't collide. When it finishes (and it can't reach 200 circles), start pushing in circles. I mean physically push them in with a physics engine:
<http://www.sgtconker.com/2010/09/article-xna-farseer-platform-physics-tutorial/> (without using gravity). | Suppose you want n = 200 circles. My suggestion is to pick a number moderately larger than n, say m = 300, and generate that many points at random locations within the square. This set of m points is your *candidate set* of circle centres. Now produce a graph containing m vertices, one for each point, in which two vertices are linked by an edge if and only if the distance between their points is less than the circle diameter -- it is exactly in this situation that we would be forbidden to include *both* circles in the solution, because they would overlap.
You can now model the problem of choosing which candidate circle centres should actually become circles as a [maximum independent set problem](http://en.wikipedia.org/wiki/Independent_set_%28graph_theory%29): find a maximum-sized set of vertices in this graph having the property that no two vertices in the set are linked by an edge. This will find a set of circle centres such that no two of their circles would overlap. If this set contains more than n circles, then discard a random selection of circles until just n remain. If fewer than n circles are found, you'll need to increase m and try again.
Unfortunately the maximum independent set problem is NP-hard, so I don't know whether it will be feasible to solve on a 300-vertex graph. (And in turn, I don't know whether 300 random centres will give you enough flexibility to find 200 non-overlapping circles...) But in any case, you would normally solve maximum independent set in one of two ways:
1. Look for a [minimum vertex cover](http://en.wikipedia.org/wiki/Vertex_cover), then take every *other* vertex to be the maximum independent set
2. Produce the complement graph (i.e. the graph in which two vertices are linked by an edge if and only if they are *not* linked by an edge in the original graph), and then find a [maximum clique](http://en.wikipedia.org/wiki/Clique_%28graph_theory%29) in this graph
Those Wikipedia pages contain links to papers describing algorithms for these problems that, while still exponential-time, are much faster than a standard "full backtracking" algorithm. A couple of things to bear in mind:
* You don't actually need the provably maximum independent set, just one >= n. So heuristics may be just fine; note the particularly simple heuristic for minimum vertex cover on the Wikipedia page.
* Beware the difference between "maximal" (easy) and "maximum" (hard) cliques/covers/independent sets! |
7,946,152 | I am searching for a concept to distribute circles in a square randomly, so that they dont overlap. All circles are of the same size. The area covered by the circles can be high, up to the theoretical maximum of ca. 90 % of the square (in which they are completely ordered). About 200 circles should be placed and I want to specify the number of circles exactly. (The distribution is needed as input for a model generation of a FE-analysis, btw)
With a straight-forward algorithm that places circles sequentially on a free spot, it is not possible to cover more than about 54%, which is not a surprise, as at some point there is just no space left. Therefore previous SO-threads do not really cover my issue (getting close: [Placing random circles without overlap (and without using brute force)?](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force))
With a simple random displacement of the circles of an ordered set of circles, the distribution seems to be "not random enough".
All concepts, I came up with so far, feel either to complicated or to brute-force-style. The approach I like most is to determine all possible positions on which the next circle can be placed, so that the left-over space is big enough to place the remaining circles. Then pick one of these positions randomly and so on. But: To determine the "capacity" of the left-over space is not easy and numerically very complex. I dont really know how to do it, and whether it can be done with reasonable numerical effort.
Second idea is a billard simulation: Place all circles in a whatever pattern and simulate a big pool billard. Pretty brute force and numerically very costly as well. I am a bit afraid of descretization issues as well.
Number 3 is more mathematical and is based on defining a potential field for every circle with a random "strength", so that there is some kind of gravitation between the circles and calculate the equilibrium state. The development of a mathematical model for this is not trivial and would be quite a mission...
So - finally - the question: What are your suggestions to solve the problem as leightweight as possible? Do you know algorithms I should look at to solve this? What are your remarks to my ideas?
Thank you all a lot in advance! I am excited to read your answers. | 2011/10/30 | [
"https://Stackoverflow.com/questions/7946152",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/645104/"
] | Start by using the [basic algorithm](https://stackoverflow.com/questions/6002407/placing-random-circles-without-overlap-and-without-using-brute-force/6002708#6002708) to draw as many as possible circles that don't collide. When it finishes (and it can't reach 200 circles), start pushing in circles. I mean physically push them in with a physics engine:
<http://www.sgtconker.com/2010/09/article-xna-farseer-platform-physics-tutorial/> (without using gravity). | @toto2 @cyborg @TokenMacGuy
Update:
I have implemented the **billard solution** with the FarseerPhysicsEngine and played around with it a bit. Within the process of implementing the solution I modified the problem a bit :): Instead of keeping all circles inside the box, I allow the circles to move outside the border and let the outside part reappear on the opposite side (pretty much like in the oldschool asteroids game). This makes my distribution suitable for infinite repetition in x and y direction, which is even better for the underlying Finite Element modelling task. This comes along with some other issues regarding the physics simulation, and as this was not part of the original question, I will only describe those, if anyone is particularly interested.
So **what I did**: I order as many circles as wanted or as fit in the most dense order possible (where the centres of the circles are in a hexagon order). I leave a margin around the circles to make the simulation more stable. It sometimes happens, that circles overlap otherwise. Every circle gets a random velocity vector and mass. Everything else is collision detection and handling, done by the physics engine.
The **outcome**: It works well for high amounts of circles.
If performed with a small number of circles, they tend to stick together. I cant really explain why. Might be that Fraseer doesn't model the collision as ideally elastic, so that energy is dissipated. I don't know whether, and if where, there is a property for that. As I set friction to zero for the movement, this could lead to this kind of clustering:
Anyway, I am quite happy with the result for many circles and - as this was the unsolved part so far, I suppose this will do. It's a shame, that I don't have the time to dig deeper into the other concepts, although I will for sure have a deeper look at them later on.
Thank you all for participating!! Was fun to get all your input! If you have further ideas or comments on the solution, please let me know. |
19,950 | I am currently porting a demo from XNA to DirectX which, as I understand it, both have coordinate systems with different handednesses.
What are the things I need to bare in mind when converting between the two? I understand not everything needs to be changed.
Also I notice that many of the 3D maths functions in some of the direct3D libraries have right handed and left handed alternatives. Would it be better to just use these? | 2011/11/19 | [
"https://gamedev.stackexchange.com/questions/19950",
"https://gamedev.stackexchange.com",
"https://gamedev.stackexchange.com/users/10079/"
] | Direct3D doesn't actually specify any handedness, so it's no longer correct to say things like "D3D has a left-handed coordinate system". You can in fact use either left-handed or right-handed in D3D; just select either of the -LH or -RH versions for the projection matrix setup functions and that is all that is required.
For example, look in your DirectX SDK for D3DXMatrixPerspectiveFovLH and D3DXMatrixPerspectiveFovRH.
The important thing is that you're consistent in your own code, so that you don't need to switch back and forth between each system. If you're dealing with existing code you should respect it's system and convert as required, but if you're porting from XNA (or from OpenGL for that matter) then just set D3D up to be right-handed too, and be done with it. | First of all, I'll refer you to an answer of mine I posted a while back:
[Why / how does XNA's right-handed coordinate system effect anything if you can specify near/far Z values?](https://gamedev.stackexchange.com/questions/7005/why-how-does-xnas-right-handed-coordinate-system-effect-anything-if-you-can-s/7006#7006)
The only real difference with the change in handedness is what happens on the Z-axis.
XNA is right handed (positive Z moves out of the screen) and DirectX can be left handed (positive Z moves into the screen) or right handed, as pointed out by mh01. Refer to his answer to make use of the right handed functionality of DX.
The easy way of converting vertices etc from one system to the other is just to negate the Z value.
Another difference you might notice is that a positive rotation along the Z axis will be different. Easiest way to figure it out: Make 2 thumbs up and point your thumbs towards you. The direction in which your fingers coil around to make a fist on your left hand is a positive rotation in the left handed coordinate system. Right hand, right-handed coordinate system.
If you've got the functions available to you form DirectX, then by all means use them. Test them out, if they work for you, great; if not, observe what's going wrong and feel free to ask another question :) |
90,087 | Does anyone have experience with installing/running Ubuntu (Karmic Koala) on a Mac Pro 8-core desktop?
Does it install smoothly? Are there issues to be aware of? | 2010/01/01 | [
"https://superuser.com/questions/90087",
"https://superuser.com",
"https://superuser.com/users/23301/"
] | [This page](https://help.ubuntu.com/community/MacPro) on the wiki lists the status of various parts of Ubuntu under the Mac Pro. Looks like it's mostly smooth sailing except for a bit of manual work on the video and audio driver side.
There's also a [Youtube video](http://www.youtube.com/watch?v=fhYx5d47Uh8) of 9.10 running smoothly on a Mac Pro. Looks like you should be alright. | I have a mac pro with 32gb ram and 8 cores. I installed Ubuntu 8.0 and it worked liked a dream! Just don't forget to install it as 64 bit! |
72,165 | I currently have a 200 amp main panel that is full. I'm planning on installing some equipment for a water well pump, water softner, etc. and it seems to make sense at this point to install a sub-panel for that equipment.
I've never had a problem doing minor electrical work around the house in the past. However, this job is bigger than I've ever done so I wanted to get some advice.
**Some details:**
* Both panels are in the basement. The wire will need to run both through the floor joists in some locations and then along a joist in another location.
* I have an electric water heater. Since the sub-panel will be installed in the same room as the water heater, I plan on removing the 2-pole 30 amp breaker for the water heater and using that slot for the breaker that will feed the sub-panel.
* I'll need 70-80 feet of wire to run from the main panel to the new sub-panel.
* Picture of current main panel attached.
* Sub-panel breakers:
+ water heater: 2-pole 30 amp
+ jet pump: 20 amp
+ well pump: 2-pole 30 amp
+ cistern relay circuit: 15 amp
+ water treatment equipment: 20 amp
I can provide more details if needed, just not sure what someone would need to know.
**Questions:**
* Does the sub-panel seem over loaded? If so, I could keep the water-heater in the main panel and free up space in the panel another way.
* I know I need four-strand wire to run to the sub-panel (2 hot, neutral, ground) but copper or aluminum and what gauge?
* When I run the wire along the floor joist, does it need to be secured to the joist or can it just hang there and rest on the drop ceiling? Seems like it should be secured to the joist with wire hanger or something.
* What are the things about this project that I don't know that I don't know. :) These are the scary things IMO...i.e. the questions I don't know enough to ask.
Thanks in advance. I'm happy to provide more details if you need them.
[](https://i.stack.imgur.com/nPlKA.jpg)
**Edit #1:**
Another question has come up: should I put a 100 amp breaker in the sub-panel to act as the "main" for the sub-panel? Or is the 100 amp breaker in the main panel sufficient? | 2015/08/21 | [
"https://diy.stackexchange.com/questions/72165",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/41682/"
] | >
> Does the sub-panel seem over loaded? If so, I could keep the water-heater in the main panel and free up space in the panel another way.
>
>
>
Seems reasonable to me. Most of the equipment won't draw anywhere near the overcurrent rating, at least not during normal operation. Motor loads will draw a higher current on start, but you shouldn't have a problem.
>
> I know I need four-strand wire to run to the sub-panel (2 hot, neutral, ground) but copper or aluminum and what gauge?
>
>
>
You can use either copper or aluminum, though I recommend copper for DIYers. Copper is quite a bit more expensive, but it's easier to work with (in my opinion). If you feel confident working with aluminum conductors, you can save some money using it.
I've covered the topic of feeder sizing [here](https://diy.stackexchange.com/a/29077/33), so I won't go into detail. If you're using copper, you'll want to use 3 AWG conductors. If you choose to use aluminum, you'll need 1 AWG conductors.
If you want to run a single cable, instead of individual conductors in conduit. You can buy what's called 3-3-3-5 SER cable (1-1-1-3 for aluminum), which will contain three 3 AWG conductors (hot,hot,neutral) and a 5 AWG grounding conductor.
>
> When I run the wire along the floor joist, does it need to be secured to the joist or can it just hang there and rest on the drop ceiling? Seems like it should be secured to the joist with wire hanger or something.
>
>
>
You'll have to attach the cable to the joists, using 1 - 1 1/4" staples or other approved means. Check the packaging, to make sure they are rated for the size cable you're using.
>
> What are the things about this project that I don't know that I don't know. :) These are the scary things IMO...i.e. the questions I don't know enough to ask.
>
>
>
The cable you'll be working with is thick and heavy, and it's not going to be fun pulling it. You'll probably want a couple helpers, to help you wrangle it.
Make sure all your connections are tightened to the manufacturer's specified torque.
If you choose aluminum conductors, make doubly sure you tighten the connections. And don't forget the [anti-oxidant](http://www.idealind.com/prodDetail.do?prodId=noalox).
Come back a day or two after the panel has been put into service, and tighten any connections that need it.
Don't forget to remove the bonding jumper between the grounded and grounding bus bars.
You'll need clamps big enough for the cable, to secure it to the panels.
>
> should I put a 100 amp breaker in the sub-panel to act as the "main" for the sub-panel? Or is the 100 amp breaker in the main panel sufficient?
>
>
>
You can usually pick up a main breaker panel, for about the same price as a main lug only (MLO) panel. In my opinion, unless the secondary panel is next to; or within sight of, the main panel. You're better served to install a main breaker panel. It simply offers better protection during maintenance, or other work within the panel.
For example. If you turn off the feeder breaker in the main panel, and start working in the secondary panel. Somebody could easily come along, and flip on the feeder breaker. Since you can't keep an eye on the breaker, you can never be sure the panel will be dead. (unless of course you're using a lockout like you should).
If the secondary panel is in a separate building or structure, then you either need a main breaker, a main disconnect, or the ability to disconnect all ungrounded conductors within 6 or less hand moves. | You could put a dozen 100 amp panels on a 200 amp service, it's all about the total calculated load, not the breaker sizes. |
72,165 | I currently have a 200 amp main panel that is full. I'm planning on installing some equipment for a water well pump, water softner, etc. and it seems to make sense at this point to install a sub-panel for that equipment.
I've never had a problem doing minor electrical work around the house in the past. However, this job is bigger than I've ever done so I wanted to get some advice.
**Some details:**
* Both panels are in the basement. The wire will need to run both through the floor joists in some locations and then along a joist in another location.
* I have an electric water heater. Since the sub-panel will be installed in the same room as the water heater, I plan on removing the 2-pole 30 amp breaker for the water heater and using that slot for the breaker that will feed the sub-panel.
* I'll need 70-80 feet of wire to run from the main panel to the new sub-panel.
* Picture of current main panel attached.
* Sub-panel breakers:
+ water heater: 2-pole 30 amp
+ jet pump: 20 amp
+ well pump: 2-pole 30 amp
+ cistern relay circuit: 15 amp
+ water treatment equipment: 20 amp
I can provide more details if needed, just not sure what someone would need to know.
**Questions:**
* Does the sub-panel seem over loaded? If so, I could keep the water-heater in the main panel and free up space in the panel another way.
* I know I need four-strand wire to run to the sub-panel (2 hot, neutral, ground) but copper or aluminum and what gauge?
* When I run the wire along the floor joist, does it need to be secured to the joist or can it just hang there and rest on the drop ceiling? Seems like it should be secured to the joist with wire hanger or something.
* What are the things about this project that I don't know that I don't know. :) These are the scary things IMO...i.e. the questions I don't know enough to ask.
Thanks in advance. I'm happy to provide more details if you need them.
[](https://i.stack.imgur.com/nPlKA.jpg)
**Edit #1:**
Another question has come up: should I put a 100 amp breaker in the sub-panel to act as the "main" for the sub-panel? Or is the 100 amp breaker in the main panel sufficient? | 2015/08/21 | [
"https://diy.stackexchange.com/questions/72165",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/41682/"
] | >
> Does the sub-panel seem over loaded? If so, I could keep the water-heater in the main panel and free up space in the panel another way.
>
>
>
Seems reasonable to me. Most of the equipment won't draw anywhere near the overcurrent rating, at least not during normal operation. Motor loads will draw a higher current on start, but you shouldn't have a problem.
>
> I know I need four-strand wire to run to the sub-panel (2 hot, neutral, ground) but copper or aluminum and what gauge?
>
>
>
You can use either copper or aluminum, though I recommend copper for DIYers. Copper is quite a bit more expensive, but it's easier to work with (in my opinion). If you feel confident working with aluminum conductors, you can save some money using it.
I've covered the topic of feeder sizing [here](https://diy.stackexchange.com/a/29077/33), so I won't go into detail. If you're using copper, you'll want to use 3 AWG conductors. If you choose to use aluminum, you'll need 1 AWG conductors.
If you want to run a single cable, instead of individual conductors in conduit. You can buy what's called 3-3-3-5 SER cable (1-1-1-3 for aluminum), which will contain three 3 AWG conductors (hot,hot,neutral) and a 5 AWG grounding conductor.
>
> When I run the wire along the floor joist, does it need to be secured to the joist or can it just hang there and rest on the drop ceiling? Seems like it should be secured to the joist with wire hanger or something.
>
>
>
You'll have to attach the cable to the joists, using 1 - 1 1/4" staples or other approved means. Check the packaging, to make sure they are rated for the size cable you're using.
>
> What are the things about this project that I don't know that I don't know. :) These are the scary things IMO...i.e. the questions I don't know enough to ask.
>
>
>
The cable you'll be working with is thick and heavy, and it's not going to be fun pulling it. You'll probably want a couple helpers, to help you wrangle it.
Make sure all your connections are tightened to the manufacturer's specified torque.
If you choose aluminum conductors, make doubly sure you tighten the connections. And don't forget the [anti-oxidant](http://www.idealind.com/prodDetail.do?prodId=noalox).
Come back a day or two after the panel has been put into service, and tighten any connections that need it.
Don't forget to remove the bonding jumper between the grounded and grounding bus bars.
You'll need clamps big enough for the cable, to secure it to the panels.
>
> should I put a 100 amp breaker in the sub-panel to act as the "main" for the sub-panel? Or is the 100 amp breaker in the main panel sufficient?
>
>
>
You can usually pick up a main breaker panel, for about the same price as a main lug only (MLO) panel. In my opinion, unless the secondary panel is next to; or within sight of, the main panel. You're better served to install a main breaker panel. It simply offers better protection during maintenance, or other work within the panel.
For example. If you turn off the feeder breaker in the main panel, and start working in the secondary panel. Somebody could easily come along, and flip on the feeder breaker. Since you can't keep an eye on the breaker, you can never be sure the panel will be dead. (unless of course you're using a lockout like you should).
If the secondary panel is in a separate building or structure, then you either need a main breaker, a main disconnect, or the ability to disconnect all ungrounded conductors within 6 or less hand moves. | I don't think that your panel is overloaded. Lots of things you have there do work only for small amount of time and don't draw electricity all the time.
For example
water heater: probably your biggest consumer, but even then it only draws when water gets below a certain temperature and then switches off.
jet pump: Works for only short periods throughout a day.
well-pump: Same deal as with jet pump.
Same goes for the rest of things you have. Yes, it might look like the panel is overloaded, but in reality, you only draw a small fraction of the panel capacity.
EDIT: Ops did not realize the topic is almost 3 years old. My bad. |
132,357 | For many centuries, magical armor has outpaced projectiles in warfare. Armor is enchanted with runes in order to make it more effective, as well as proscribed certain abilities to it. Runes are inscribed into the suit and then placed inside a ritual circle. A mage will then chant the incantation which will fill the runes with aether and activate their power. This spell can take up to 6 hours, depending on how specialized or powerful the suit is to be. Sets of runes, or packages, work together to give the suit its power. These packages can increase strength, speed, resistance to certain attacks, etc.
Runes are generally large and take up a lot of space, which is why they are not found on arrows or bullets. This has given armor the advantage over projectiles for most of history. Recently however, technology has been invented which can inscribe these runes into projectiles with lasers. They are made as small as neccessary in order to fit, making them more effective. Then they are enchanted by the mage in the same way as armor. However, having machines inscribe tiny runes onto them is expensive and time consuming. They also have to be enchanted one at a time, and cannot be done in groups. Because of this, they are hard to mass produce.
How can I make design a way to make projectiles cost effective enough to be practical? | 2018/12/08 | [
"https://worldbuilding.stackexchange.com/questions/132357",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/52361/"
] | There are two ways of approaching your problem - none will actually change your production method of magical bullets but they will affect their usage.
One is trying to outgun magical armor with a **massive number of bullets**. This is a scenario known from the invention of machine guns (it features prominently on screen in 'The last samurai'). Here, **not necessarily all bullets have to be magical**. Ff the first 10 magical bullets pierce the armor enough to let normal bullets - in particular ones fired en masse in very short amounts of time, so that magically increased dodging or speed will not protect or help the armor wearer sufficiently - enter, the armor wearer stands almost no chance. As armor tends to make its wearer less agile and fast than a trained fighter would be without such armor, this makes armor quite unattractive to wear in open combat against gun-fighters.
The second option is that the bullets which are so expensive to produce and have to be enchanted one by one are enchanted to gain more power than just the ability to pierce magical armour. The simple and efficient way would be to **add heat/fire damage** as this turns heavy armour made of metal against its user who is cooked alive by his own protective gear. Any **explosive effect** caused or increased by the enchantment will cause the armor wearer a type of damage against which his armor is not designed to protect. Since you can use laser technology the inscribe your runes, your guns will likely not be renaissance level low precision guns, but you will have high tech guns available. With specially enchanted bullets which each have to ability to kill or incapacitate an armor wearing fighter a single sniper with a high tech sniper gun can take out dozens of fighter from afar with enough time to reload his gun in between and no need for massive amounts of bullets. | It would depend on how the magic works. Can you use an arrangement of mirrors to allow one mage to enchant multiple ritual circles at the same time? Or can the ritual be done mechanically (like with Tibetan prayer wheels, which supposedly still work if they are turned by electrical or water power rather than a human)? For instance, if the ritual involves a sequence of hand gestures around the object being enchanted, you could have a kind of pantograph arrangement where the mage's hands are connected by wires and pulleys to a dozen wooden hands (or mummified mage's hands), each enchanting a separate arrow.
If nothing like that will work, then you need to reduce the cost of mages, by training more of them and/or making them work on more exploitative terms. |
132,357 | For many centuries, magical armor has outpaced projectiles in warfare. Armor is enchanted with runes in order to make it more effective, as well as proscribed certain abilities to it. Runes are inscribed into the suit and then placed inside a ritual circle. A mage will then chant the incantation which will fill the runes with aether and activate their power. This spell can take up to 6 hours, depending on how specialized or powerful the suit is to be. Sets of runes, or packages, work together to give the suit its power. These packages can increase strength, speed, resistance to certain attacks, etc.
Runes are generally large and take up a lot of space, which is why they are not found on arrows or bullets. This has given armor the advantage over projectiles for most of history. Recently however, technology has been invented which can inscribe these runes into projectiles with lasers. They are made as small as neccessary in order to fit, making them more effective. Then they are enchanted by the mage in the same way as armor. However, having machines inscribe tiny runes onto them is expensive and time consuming. They also have to be enchanted one at a time, and cannot be done in groups. Because of this, they are hard to mass produce.
How can I make design a way to make projectiles cost effective enough to be practical? | 2018/12/08 | [
"https://worldbuilding.stackexchange.com/questions/132357",
"https://worldbuilding.stackexchange.com",
"https://worldbuilding.stackexchange.com/users/52361/"
] | There are two ways of approaching your problem - none will actually change your production method of magical bullets but they will affect their usage.
One is trying to outgun magical armor with a **massive number of bullets**. This is a scenario known from the invention of machine guns (it features prominently on screen in 'The last samurai'). Here, **not necessarily all bullets have to be magical**. Ff the first 10 magical bullets pierce the armor enough to let normal bullets - in particular ones fired en masse in very short amounts of time, so that magically increased dodging or speed will not protect or help the armor wearer sufficiently - enter, the armor wearer stands almost no chance. As armor tends to make its wearer less agile and fast than a trained fighter would be without such armor, this makes armor quite unattractive to wear in open combat against gun-fighters.
The second option is that the bullets which are so expensive to produce and have to be enchanted one by one are enchanted to gain more power than just the ability to pierce magical armour. The simple and efficient way would be to **add heat/fire damage** as this turns heavy armour made of metal against its user who is cooked alive by his own protective gear. Any **explosive effect** caused or increased by the enchantment will cause the armor wearer a type of damage against which his armor is not designed to protect. Since you can use laser technology the inscribe your runes, your guns will likely not be renaissance level low precision guns, but you will have high tech guns available. With specially enchanted bullets which each have to ability to kill or incapacitate an armor wearing fighter a single sniper with a high tech sniper gun can take out dozens of fighter from afar with enough time to reload his gun in between and no need for massive amounts of bullets. | **They are cost effective because they work with one shot.**
>
> “Arrow! Black arrow! I have saved you to the last. You have never
> failed me and I have always recovered you. I had you from my father
> and he from of old. If ever you came from the forges of the true king
> under the Mountain, go now and speed well!”
>
>
> ― J.R.R. Tolkien, The Hobbit
> <https://www.goodreads.com/quotes/128057-arrow-black-arrow-i-have-saved-you-to-the-last>
>
>
>
Like the Black Arrow that finds the weak spot in Smaug's armor, enchanted projectiles are worth the expense because they perform amazing, and possibly one-time feats. As opposed to enchanted armor which is used again and again, the enchantment durable over months and years, the enchanted projectile (possibly when invoked, as here) expends its enchantment in a single amazing and successful-against-all-odds shot.
This also makes for much more awesomeness in a story. |
162,178 | Last year I had an infestation of carpenter ants, so I contacted a pest control company and paid for a year's worth of service. Now, exactly a week after the contract expired, I'm seeing them come back.
I'm planning on taking care of it myself this year, since the chemicals cost less than a month's worth of service from the pest control company.
I know that the two most common ways of treating for carpenter ants are:
1.) [Boric acid bait](https://www.domyown.com/niban-granular-bait-lb-shaker-p-1487.html)
2.) [Fipronil spray](https://www.domyown.com/taurus-sc-termiticide-p-1816.html)
Is either one of these treatments more effective than the other, and/or is the combination of these treatments more effective than either on its own? | 2019/04/16 | [
"https://diy.stackexchange.com/questions/162178",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/99555/"
] | You are just chasing your tail. As long as there is exposed wood and a convenient source of water, you will have carpenter ants.
The solution is to improve your roofing and gutters to keep the house dry. | My understanding (not a pest professional) is that using both negates the effectiveness of the bait. If you kill them before they take the bait home, it does no good.
The idea with bait is to have them take it back and "kill the colony" rather than killing the individual foraging ants as sprays tend to do.
*Of course, if you run a pest control company and care more about keeping the business going than eliminating pests, you might choose a method that stops working a week after you stop treating, but charge the customer for two methods, even if one negates the other :-) But I'm a terrible cynic sometimes.*
If your infestation includes substantial dry areas you might wish to add insecticidal diatomaceous earth (not the pool version, they are processed differently, as I understand it.) If the area stays dry, you only need to apply it once. It works on a different principle than chemical insecticides, and is supposed to be difficult to become resistant to as a result. |
162,178 | Last year I had an infestation of carpenter ants, so I contacted a pest control company and paid for a year's worth of service. Now, exactly a week after the contract expired, I'm seeing them come back.
I'm planning on taking care of it myself this year, since the chemicals cost less than a month's worth of service from the pest control company.
I know that the two most common ways of treating for carpenter ants are:
1.) [Boric acid bait](https://www.domyown.com/niban-granular-bait-lb-shaker-p-1487.html)
2.) [Fipronil spray](https://www.domyown.com/taurus-sc-termiticide-p-1816.html)
Is either one of these treatments more effective than the other, and/or is the combination of these treatments more effective than either on its own? | 2019/04/16 | [
"https://diy.stackexchange.com/questions/162178",
"https://diy.stackexchange.com",
"https://diy.stackexchange.com/users/99555/"
] | You are just chasing your tail. As long as there is exposed wood and a convenient source of water, you will have carpenter ants.
The solution is to improve your roofing and gutters to keep the house dry. | Boric acid is the best consumer treatment, far and away, imho. I'm talking eradication. Look up some recipes to get the bait/poison ratio right and it should be *very* effective. If you make it too strong, it will quickly knock down the wave, but they will eventually regroup and return.
Unlike sprays, you can use powder to form physical barriers on parts under-attack by dusting the complete surfaces with virtually harmless and fire-retarding boric acid. They simply cannot get to the problem area without getting dosed; it cannot miss!
It's also cheap and safe for kids and pets, which other treatments are not. Some people even eat the stuff as an arthritis cure; I don't really recommend that, but it's pretty harmless to us and ours for what it does to those dang ants! |
31,339 | In Christian hymnbooks today it is common to find hymns that were written in the 1700s or 1800s. However, most of the time these hymns have been adapted, to modernize older language, or to adjust the meaning of a phrase for a broader audience.
According to current copyright law in the United States, printed works published before 1923 are in the public domain. Are the adapted versions of pre-1923 hymns that appear in current hymnbooks also in the public domain? What about translations?
An example is the hymn "How Firm a Foundation." Different texts can be compared here:
<https://hymnary.org/text/how_firm_a_foundation_ye_saints_of/compare>
I am interested mainly in the United States copyright / public domain law. | 2018/08/29 | [
"https://law.stackexchange.com/questions/31339",
"https://law.stackexchange.com",
"https://law.stackexchange.com/users/20648/"
] | According to [US law according to Cornell](https://www.law.cornell.edu/uscode/text/17/103), copyright applies to derivative works. A derivative work is an original work based on a previous work ([Definitions](https://www.law.cornell.edu/uscode/text/17/101)), so the adaptations would be copyrightable unless they were held to be unoriginal. In general, the courts don't require much creativity to consider a work original. Translations are original works.
Therefore, the adaptations are almost certainly under copyright, while the originals remain public domain. | Unless the adaptation is itself old enough to be out of copyright, or is so close to the original that it is not considered original enough to support a copyright (and that is a quite low bar), each such adaptation has its own copyright under US law, which would have been initially owned by the creator of the adaptation. Such adaptations are just as protected as if they were not adaptations, but independent original works. |
440 | [This question](https://hardwarerecs.stackexchange.com/q/2100/8) has been closed (by three users and a moderator) as 'too broad'. The reason given was this:
>
> This question has been closed because it appears to be asking about a very conceptual technology that isn't implemented in common hardware, thus reliable recommendations can't be made. For more information on question quality, please see our guidelines. If you can rework your question to fit the site better, it can be reopened. Thanks!
>
>
>
*Personally* (not officially - this is opinion), I don't think this is right. I can't say I remember seeing any posts or definitions that mean conceptual technology is off-topic; moreover, the requirements defined in the question narrow down the potential results to very few products. In contrast to the reason given, I think conceptual technologies even in the early stages of development are still on-topic - the fact that there aren't many implementations shouldn't make them off-topic. It *does* mean that the question is unlikely to get many answers (or even any at all), but that's a product of the narrow scope and is the same for any other question. Additionally, our normal quality guidelines should cover answers well enough - if it's just a one-Google result without much effort, we can delete it.
Let's have a discussion - is this closure correct or not? | 2016/02/28 | [
"https://hardwarerecs.meta.stackexchange.com/questions/440",
"https://hardwarerecs.meta.stackexchange.com",
"https://hardwarerecs.meta.stackexchange.com/users/8/"
] | We have had weird questions before. For example, there was a question about [Faraday cages](https://hardwarerecs.stackexchange.com/questions/498/tempest-proof-pc-notebook). This was deleted as unclear, because the OP rambled and sounded extremely paranoid, not because the question was bad.
That question spawned a [meta discussion](https://hardwarerecs.meta.stackexchange.com/q/226/57), in which both answers basically said (paraphrasing...):
>
> If the requirements can be defined, even if they are for unusual equipment, the question should remain open.
>
>
>
I agree with this answer.
---
In this particular case, I don't have the knowledge needed to say if this is to broad or unclear. The OP has provided several background links, which is helpful though. I'm inclined to say "leave it open". If they don't receive answers, then I think that partially answers their question. | You're focusing on the wrong part of my close reason here. Maybe I could have used a slightly better word than *conceptual*, but the important part is how NISC "isn't implemented in common hardware, so reliable recommendations can't be made."
This technology is of course a very specific one no doubt; not too many products out there make use of it. But I'm not sold on that fact here. This technology is also something pretty much no one has experience with nowadays, and that's a big factor in fitting on the site. If no one will be able to provide a *reliable* recommendation (meaning a recommendation sourced from a person's prior experience), does it really belong on the site?
If so, I don't have a problem here. I'm not dead set on this decision and I could change my mind given a good argument. |
91,956 | What is appropriate for a person to wear? Do those standards change for men or women? How do we know? Why does this, which seems like an important topic, not have much of an explicit commandment in the Bible (for example, you ought to wear something up to the knees, or not show cleavage, like many Christian churches and colleges)?
Clearly, the Bible forbids nudity.
Genesis 3:7
>
> And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons.
>
>
>
Genesis 3:21
>
> Also for Adam and his wife the Lord God made tunics of skin, and clothed them.
>
>
>
Nudity was taken very seriously.
Genesis 9
>
> Then he drank of the wine and was drunk, and became uncovered in his tent. **22** And Ham, the father of Canaan, saw the nakedness of his father, and told his two brothers outside. **23** But Shem and Japheth took a garment, laid it on both their shoulders, and went backward and covered the nakedness of their father. Their faces were turned away, and they did not see their father’s nakedness.
>
>
>
Uncovering someone's nakedness is considered a sexual act.
Leviticus 18
>
> **6** ‘None of you shall approach anyone who is near of kin to him, to uncover his nakedness: I am the Lord. **7** The nakedness of your father or the nakedness of your mother you shall not uncover. She is your mother; you shall not uncover her nakedness.
>
>
>
Nudity includes at least the genitals. The priests were to wear undergarments that extended from the waist to the thigh to avoid uncovering themselves (this is the closest to a formal instruction I know of; it seems like one should at least wear something equivalent to boxers in coverage). Why not specify to wear this all the time?
Exodus 28
>
> **42** And you shall make for them linen trousers to cover their [m]nakedness; they shall reach from the waist to the thighs. **43** They shall be on Aaron and on his sons when they come into the tabernacle of meeting, or when they come near the altar to minister in the holy place, that they do not incur iniquity and die.
>
>
>
Exodus 20:26
>
> Nor shall you go up by steps to My altar, that your nakedness may not be exposed on it.
>
>
>
There is a passing mention of nudity of the legs, though it isn't clear to me whether the first line about having bare legs isn't a poetic building up to the nakedness being uncovered, and not the act itself.
Isaiah 47:2-4
>
> Take the millstones and grind meal. Remove your veil, Take off the skirt, Uncover the thigh, Pass through the rivers. Your nakedness shall be uncovered, Yes, your shame will be seen;
>
>
>
Here, one might deduce an association between sexual appeal and nakedness:
Ezekiel 16:7-8
>
> 7 I have caused thee to multiply as the bud of the field, and thou
> hast increased and waxen great, and thou art come to excellent
> ornaments: thy breasts are fashioned, and thine hair is grown, whereas
> thou wast naked and bare. 8 Now when I passed by thee, and looked upon
> thee, behold, thy time was the time of love; and I spread my skirt
> over thee, and covered thy nakedness:
>
>
>
Another passage of interest:
John 21:7
>
> Therefore that disciple whom Jesus loved saith unto Peter, It is the Lord. Now when Simon Peter heard that it was the Lord, he girt his fisher’s coat unto him, (for he was naked,) and did cast himself into the sea.
>
>
>
Later in the New Testament, dressing appropriately is clearly desirable, but no clear definition is given to what that means, that would not perhaps vary.
1 Timothy 2:9
>
> in like manner also, that the women adorn themselves in modest apparel, with propriety and moderation..."
>
>
>
How would one determine what bathing suit to wear? Whether clothes are too tight? Too short? Whether wearing crop-tops or two-pieces is ok; and if, for example, men can bare their chests?
Personally, I have a very conservative view on these topics. However, being married has brought out this topic as a source of considerable worry and pain.
Having an objective standard would be helpful either way. It seems like every person has his own standard, and is difficult to explain without offense. Not only that, but cultural issues change the decency of what people wear. For example, in some places, it is normal for women to uncover their breasts for lactation, but it might seem sexual to wear tight pants, whereas in the West it is rather the reverse. (Indeed, one could make an extreme argument that notwithstanding cultural norms, the only requirement about covering nudity goes from the waist to the thigh.) However, we are the same humanity, with the need for, presumably, the same decency.
So, one could pose this question another way: how did God clothe Adam and Eve in the garden; and if it is important to follow that standard, why is it not expressed more clearly? Were the Israelites, as God's people, strict on this, as there is seemingly a gap in the law on this topic?
A related question: [Does the Bible command women to cover their breasts?](https://christianity.stackexchange.com/questions/39600/does-the-bible-command-women-to-cover-their-breasts) | 2022/07/18 | [
"https://christianity.stackexchange.com/questions/91956",
"https://christianity.stackexchange.com",
"https://christianity.stackexchange.com/users/59730/"
] | **Is there an objective, theological standard of decent/modest dress?** *(Denominational Survey)*
Historically, I believe the standard across the board amongst Christian denominations has changed over the years, especially in our modern times.
Fashions come and go, but I firmly believe that many modern fashions offend God in our present day and age. That said, it may be just me, but that is okay.
One Baptist Church has the following regulations concerning one’s dress. They are very conservative and traditional.
>
> **Purposes for Establishing these Regulations**
>
>
> For members serving in these positions to demonstrate respect and reverence to God, and reflect appropriateness, godliness, and modesty.
> To demonstrate love and respect for fellow believers by carefully avoiding being a source of temptation or an offence to them.
>
>
> To prevent the recipients of our ministry from being distracted and hindered from a proper mental focus while we minister to them.
>
>
> **Regulations**
>
>
> Men (13 & up)
>
>
> * Full length pants (no demin)
> * Front button polo or dress shirts. Sweaters are acceptable. (No t-shirts)
> * Shoes and socks
> * Jewelry
>
>
> + No pierced jewelry
> + No necklaces on outside of clothing
>
>
> **Women (13 & up)**
>
>
> * Skirt or dress is required
>
>
> + Must completely cover the knee while standing or sitting
> + Any slits must stop at the knee
> * Top (pertains to blouse or dress)
>
>
> + Must cover cleavage completely while standing, sitting, or bending over
> + The back neck line must be above the shoulders
> * Snugness of fit for skirt, dress, blouse, or top:
>
>
> + Not form-fitting, or body hugging
> + Must drape and not cling
> + No exposed midriff
> + Nothing see-through
>
>
> Disclaimer: This policy cannot cover every possible situation. Other obviously distracting, immodest or giving-a-wrong-message type of attire will also be prohibited.
>
>
> [Holmen Baptist Church](https://www.holmenbaptist.com/dress-guidelines)
>
>
>
I live in a Mennonite area and the women are frequently seen in public wearing a head covering and long dresses, even in summer. The Amish do almost the same.
>
> The topic of Amish clothing can be a complicated one. As we’ve discussed before, Plain Amish and Mennonites come from many different sects. Each group has its own patterns and however slight those differences may appear to us, I’ve witnessed time and again how those slight changes in style or fabric are very distinguishing to them. But the similarities can make it difficult to generalize on this topic, so bear in mind that what’s true of the clothing for one group may not be true of another.
>
>
> **Common Items of Dress**
>
>
> **Men**
>
>
> Amish men dress for practicality and that primarily includes a button-down, collared shirt of a solid color and a pair of rough (or broadcloth) trousers that are often made from wool, cotton, and in more recent times, polyester. Their pants are held up by suspenders. It wasn’t that many years ago when an Amish man wore a simple black coat unless working. That is not always the case anymore. They almost always wear a hat, and the exact look of the hat is one of the distinguishing features among the various sects of Amish. They do not use buckles on their clothing, but the men have buttons on their shirts and for the men in a more conservative Plain community, they use buttons on their pants instead of zippers. In most Amish sects the men who are married keep a beard, but they do not have a mustache. Single Amish men keep their face shaven until their wedding day.
>
>
> **Women**
>
>
> Amish women dress for modesty above all else, but their clothing is also practical. Their garments cover their bodies without becoming so much of an ornament that they could be deemed non-functional. Typically the females bind their hair in some form of braid or bun and cover it with a black or white cap (prayer Kapp). Their main form of clothing is a cape dress with an apron to cover it. Apron and cap styles vary according to the different Amish groups. Black stockings are usually worn underneath the dress. If cold, women may use a simple black sweater or jacket. If you see an Amish woman in a black cape, she should also have on a black bonnet, but she can wear the black bonnet without the cape. Like the men, women do not use buckles or any other type of ornament on their clothing. Unlike men, women’s dresses and aprons avoid buttons. Their sweaters or overcoats have buttons now, but that was not always the case. They may use one or two very small buttons on their dresses, mostly they use a lot of straight pins in lieu of buttons.
>
>
> **But why?**
>
>
> This style of clothing is considered outdated by society, but the Amish have held on to this same basic style for a number of reasons. Our clothing, as English, often reflects who we are. We can identify the age, interests, economic status, and/or cultural background of a person just by glancing at his or her clothing. Even more commonly, we use uniforms to identify some professions. Oftentimes an individual’s identity is tied to the way he or she chooses to dress. The Amish use this principle as a way to visually show others their beliefs.
>
>
> The Amish believe that God has called them to be completely separate from the world and its negative influences. Choosing to wear clothing that sets them apart as different immediately divides them from the English. The choice to dress a certain way strengthens the community’s bonds and declares their commitment to the principles of the Amish church.
>
>
> In addition, humility is an important and central part of the Amish beliefs. They maintain that dressing as you please creates pride in your appearance or choices. According to the Old Ways, if one individual stands out within a group, that person tends to develop boastful ideas about his or her success or individuality. Instituting a dress code, then, is meant to keep the Amish away from pride so that they can spend their time focusing on the state of their heart and soul, not the outward appearance.
>
>
> The Amish style of dress also highly stresses modesty. The women must cover themselves almost completely, down to keeping their hair hidden under a cap. They believe that this type of modesty in dress is necessary to keeping their hearts and bodies pure.
>
>
> [Why the Amish Dress the Way They Do?](https://www.cindywoodsmall.com/2012/05/14/why-the-amish-dress-the-way-they-do/)
>
>
>
[](https://i.stack.imgur.com/miD5a.jpg)
[Modesty](https://en.m.wikipedia.org/wiki/Modesty) in dress is also cultural concept, even in the West, as seen above in the [plain dress](https://en.m.wikipedia.org/wiki/Plain_dress) of [Amish](https://en.m.wikipedia.org/wiki/Amish) women on an American beach in 2007.
I have noticed that many are coming to our Catholic Churches with very immodest dress these days. Priests simply do not address this issue as well as they should be doing.
Many Catholics are not aware that the Vatican itself has addressed this issue and we are well below the level Rome has put down. Here are some of the Church’s directives:
>
> **Modesty Standards**
>
>
> On January 12, 1930, the Sacred Congregation of the Council, by mandate of Pope Pius XI, issued emphatic instructions on modesty of dress to all bishops, directing them to insist on these prescriptions: **"We recall that a dress cannot be called decent which is cut deeper than two fingers breadth under the pit of the throat, which does not cover the arms at least to the elbows, and scarcely reaches a bit beyond the knee. Furthermore, dresses of transparent material are improper.**
>
>
> "Let parents keep their daughters away from public gymnastic games and contests; but, if their daughters are compelled to attend such exhibitions, let them see to it that they are fully and modestly dressed. Let them never permit their daughters to don immodest garb."
>
>
> Rufino J. Cardinal Santos, Archbishop of Manila, also quotes these standards as "The Church's Stand concerning Modesty in Dress" in his Pastoral of December 6, 1959. The feminine loss of the sense of modesty was indicated by Pope Pius XII who said: "Now many girls do not see anything wrong with following certain shameless styles (fashions) like so many sheep. They would surely blush if they could only guess the impressions they make and the feelings they evoke (arouse) in those who see them." (July 17, 1954.)
>
>
> "O Christian mothers, if only you knew the future distress, peril and ill-restrained shame that you prepare for your sons and daughters by imprudently accustoming them to live barely clothed, and permitting them to lose the sense of modesty, you would be ashamed of yourselves, and of the harm done to the little ones entrusted to you by Heaven to be reared in a Christian dignity and culture."
>
>
> And, men also are held to the virtue of modesty; witness the admonition of Canadian bishops in May of 1946: "Man himself does not escape from the inclination of exhibiting his flesh: some go in public, stripped to the waist, or in very tight pants or in very scanty bathing suits. They thus commit offenses against the virtue of modesty. They may also be an occasion of sin (in thought or desire) for our neighbor."
>
>
> The opinion which allows custom to dictate the question of modesty was refuted by Pope Pius XII in one short sentence: "There always exists an absolute norm to be preserved."
>
>
> Custom, of course, pays no attention to absolute norms; but, it is a follower of this false principle: "... the majority cannot go wrong."
>
>
> To say that "... modesty is a matter of custom" is just as wrong as to say that "... honesty is a matter of custom."
>
>
> What about those who teach "What is customary does not affect us?"
>
>
> Pope Pius XII calls this application of an ancient principle to the virtue of modesty, "the most insidious of sophisms." He calls attention to the fact that some people use this sophism "...in order to brand as 'old fashioned' the rebellion of honest people against fashions they consider too bold."
>
>
> The Pope's pronouncements make no distinctions for various types of garments. Pius XII states "...an unworthy, an indecent mode of dress has prevailed" without any distinction of place, "on beaches, in country resorts, on the streets, etc." (Aug. 29. 1954)
>
>
> His quotation: "Vice necessarily follows upon public nudity," applies as well to the beaches, or the streets, or resorts, or elsewhere.
>
>
> Cardinal Pla y Daniel, Archbishop of Toledo, Spain, stated in 1959: "A special danger to morals is represented by public bathing at beaches... Mixed bathing between men and women, which is nearly always a proximate occasion of sin and a scandal, must be avoided."
>
>
> Modern Catholics may now consider themselves "far too adult" and disdain such directives, but nevertheless they remain the wise counsels of our Holy Mother the Church.
>
>
> [Some Directives of the Magisterium on Christian Modesty](https://www.olrl.org/virtues/modcrus.shtml)
>
>
>
Modesty and clothing appearance is mentioned several times in Scriptures. Our non-denominational brethren may be interested in the following Scriptural sources:
| [1 Corinthians 12:23](https://www.biblegateway.com/passage/?search=1%20Corinthians%2012%3A23&version=NIV) |
| --- |
| And the parts that we think are less honorable we treat with special honor. And the parts that are unpresentable are treated with special modesty. |
| [1 Timothy 2:9](https://www.biblegateway.com/passage/?search=1%20Timothy%202%3A9&version=NIV) |
| --- |
| I also want the women to dress modestly, with decency and propriety, adorning themselves, not with elaborate hairstyles or gold or pearls or expensive clothes. |
| [1 Peter 3:3-4](https://www.biblegateway.com/passage/?search=1%20Peter%203%3A3-4&version=NIV;KJV) |
| --- |
| 3 Your beauty should not come from outward adornment, such as elaborate hairstyles and the wearing of gold jewelry or fine clothes. 4 Rather, it should be that of your inner self, the unfading beauty of a gentle and quiet spirit, which is of great worth in God’s sight. |
| [Romans 12:2](https://www.biblegateway.com/passage/?search=Romans%2012%3A2&version=NIV) |
| --- |
| Do not conform to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God’s will is—his good, pleasing and perfect will. |
| [Matthew 5:28](https://www.biblegateway.com/passage/?search=Matthew%205%3A28&version=NIV) |
| --- |
| But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart. |
| [Deuteronomy 22:5](https://www.biblegateway.com/passage/?search=Deuteronomy%2022%3A5&version=NIV) |
| --- |
| A woman must not wear men’s clothing, nor a man wear women’s clothing, for the LORD your God detests anyone who does this. |
| [1 Samuel 16:7](https://www.biblegateway.com/passage/?search=1%20Samuel%2016%3A7&version=NIV) |
| --- |
| But the Lord said to Samuel, “Do not consider his appearance or his height, for I have rejected him. The Lord does not look at the things people look at. People look at the outward appearance, but the Lord looks at the heart.” |
| [1 Corinthians 6:19-20](https://www.biblegateway.com/passage/?search=1%20Corinthians%206%3A19-20&version=NIV) |
| --- |
| 19 Do you not know that your bodies are temples of the Holy Spirit, who is in you, whom you have received from God? You are not your own; 20 you were bought at a price. Therefore honor God with your bodies. |
Some may think that nudity is quite fashionable considering that both Adam and Eve were created nude and were not ashamed. But that was before the fall of our first parents. There exists a [tradition](https://christianity.stackexchange.com/questions/47688/adam-and-eve-clothed-in-light-before-the-fall-origin-of-this-belief) that in the beginning both Adam and Eve were clothed in light prior to their fall. After all it was only after they had sinned that they realized they were naked. There clothing of light was removed. After their fall [God clothed them in skins](https://www.biblegateway.com/verse/en/Genesis%203%3A21). | Being guided by your statement in the comments section of your question; namely, ". . . my question is about a theological minimum that is culture- and perhaps denomination-insensitive," I'm going to set the stage for my answer to your question by quoting Supreme Court Justice Potter Stewart [who in 1964] "tried to explain 'hard-core' pornography, or what is obscene, by saying, 'I shall not today attempt further to define the kinds of material I understand to be embraced... [b]ut I know it when I see it . . . '"
Clearly, the biblical notion of modesty--and its opposite, indecency or immodesty--is addressed in numerous passages of Scripture, many of which you cited in your question. Taking Justice Stewart's comment on obscenity and tweaking it a little bit, I'd say that regarding immodesty, "I know it when I see it!" Many Christians of virtually any stripe would probably agree with me. Having come from a Plymouth Brethren background, I grew up with an awareness, in a general sense, of what immodesty entailed.
A Christian summer camp I attended, which my father was instrumental in founding in 1953, made clear to potential campers and their parents that girls were not allowed to wear bikinis during swim time. (Also on the list of forbidden behavior were the three Ss: swearing, smoking, and smooching!) In the minds of the camp's founders and subsequent directors and board members, one evidence of immodesty is the public showing of too much skin, particularly by girls and women. I also attended another, more conservative, Christian summer camp where girls and guys swam at different times.
Interestingly, of the many antonyms for the word *modesty*, as found on the website [wordhippo](https://www.wordhippo.com/what-is/the-opposite-of/modesty.html), only about three words are directly applicable to immodesty of dress (or undress), while the scores of other words are related to pride, braggadocio, and similar words.
I may be reading too much into this finding, but in 2022, if I were to come out publicly against the wearing of string bikinis by women at beaches, I would certainly be roundly criticized for being sexist! According to the politically correct crowd, a man who lusts after a scantily clad woman is clearly in the wrong, whereas the woman is free to dress any way she wants to. Accordingly, upon seeing such a woman, a man is to avert his gaze and learn to behave himself and stop objectifying women.
Frankly, the part of not objectifying women I agree with wholeheartedly. Being a man, however, I find that lusting after a young woman in a string bikini is much "easier" than lusting after the same woman who is clothed from head to toe in burlap! That is not to say that every man would find lusting after such a woman to be impossible, but it would simply be harder and less likely to happen.(Paraphilias are also an exception to the burlap example, since unusual and uncommon fetishes do exist, such as foot fetishes, to name but one.)
In the apostle Paul's day, his concern about Christian women's fashion choices stemmed from common class distinctions that allowed some Christian women to dress to the nines, while others of lesser means were forced to dress in hand-me-downs and used clothing from thrift stores (I'm assuming the equivalent existed back then!). The same could be said of expensive hairdos and makeup. Paul's concern also was related to the clothing and cosmetics associated with prostitutes and courtesans, who were expected to dress provocatively.
Where does all this lead us today as 21st-century believers, particularly in first-world nations?
For one thing, cultural factors regarding modesty are just as relevant today as they were in the first- and previous centuries. They may differ in the finer-and more culturally derived proscriptions, but there seems to be a legitimate basis for saying that mores and folkways concerning modesty, for both women ***and*** men, are universal. Even in cultures where the exposure of women's breasts in public is no big deal, there are likely other behaviors that are frowned upon, such as a husband and wife engaging in sex in full view of their children or even the public!
In Paul's day and in our day, Christian women and men are commanded by our Lord to be considerate of their fellow believers and examples to outsiders. They are not, for example, to show favoritism to wealthy and well-dressed attendees to their public functions(see James 2:1 ff.). Godly women are to known for their good deeds and modesty.To dress in the latest--and often very expensive--clothing fashions could cause women of lesser means to feel inferior, which would be a violation of the principle of love.
Am I implying that all Christian women--and men for that matter--are to engage in uniformity of dress? Clearly, no. God is a God of variety. He clothes the lilies of the field with beauty that King Solomon could not match with the finest finery (see Matthew 6:28-30). If that is so, people, who are of much more worth than flowers that fade and die shortly after they appear, can expect God to provide them with suitable clothing. (As a personal aside, as a graduating senior in high school I was voted "best dressed," but my wardrobe was far from expensive.)
We Christians may not be able to afford the latest and most expensive clothing, but God does call some believers to come before wealthy people and public figures as part of His ministry for them. For such people, who may be called by God to attend a banquet or a board meeting, for example, to be dressed in clothes made from camel's hair while munching on locusts and wild honey (see Matthew 3:4 and Mark 1:6), would be rude and disrespectful. Certainly a decent suit and tie (or dress for a woman) and a pair of shined shoes would be more appropriate and God-honoring attire.
In short, the Bible assumes that modesty in dress is a virtue, and immodesty in dress is a vice. Christian women and men are held by God to a higher standard than unbelievers. Christians are to be salt and light before a watching world. Some Christian denominations may come down harder on their rules and regulations regarding dress than other denominations. Both they and the more liberal denominations would do well to be guided by the following rule of thumb:
* In essentials, unity
* In non-essentials, liberty
* In all things, charity |
58,722 | I have a web application in which Windows Authentication is configured. I want to configure FBA for the same web application. I know I can extend the web application to a different zone and configure FBA for that zone. But I'm looking for a solution without extending the web application.
Based on the URL the user should be redirected to either FBA or Windows Authentication.
Any ideas? | 2013/02/04 | [
"https://sharepoint.stackexchange.com/questions/58722",
"https://sharepoint.stackexchange.com",
"https://sharepoint.stackexchange.com/users/407/"
] | You can configure FBA on the same web application in SharePoint 2010 without having to extend it. (Your web application will need to be configured to use Claims-based authentication and not classic...I'm assuming that's already the case).
There are numerous tutorials about the steps required to configure FBA, which generally boil down to:
* Creating the ASP.NET membership and role providers
* Modifying the web.config files for the FBA web application, central administration, and SharePoint's security token service
* Configuring users
* Setting up the appropriate authentication provider in central administration and testing
There is a good tutorial that uses the ASP.NET SQL Membership and Role providers [here](http://msdn.microsoft.com/en-us/library/gg252020%28v=office.14%29.aspx), but you can substitute your own providers.
Out of curiosity, how would you plan to redirect users based on URL if you don't want to extend the web application? The whole point of mixed mode authentication is that the same web application URL can support multiple authentication providers. This helps when it comes to things like search (i.e., search has to use an NTLM account for crawling, and with the same URLs in place, FBA users with appropriate permissions can more readily access this content).
If you did want to do any special redirection, you would need to create your own **custom sign in page** and specify it in central administration for the web application where you are configuring authentication providers. An example that does this based on client IP address can be found [here](http://www.orbitone.com/en/blog/archive/2010/06/23/sharepoint-2010-mixed-authentication-automatic-login.aspx). | There is no need to extend the application.
From CA(Central Admin) Select your web application and allow windows authentication and FBA authentication.
So that in login page you will find drop down with both window authentication and FBA authentication option. |
58,722 | I have a web application in which Windows Authentication is configured. I want to configure FBA for the same web application. I know I can extend the web application to a different zone and configure FBA for that zone. But I'm looking for a solution without extending the web application.
Based on the URL the user should be redirected to either FBA or Windows Authentication.
Any ideas? | 2013/02/04 | [
"https://sharepoint.stackexchange.com/questions/58722",
"https://sharepoint.stackexchange.com",
"https://sharepoint.stackexchange.com/users/407/"
] | You can configure FBA on the same web application in SharePoint 2010 without having to extend it. (Your web application will need to be configured to use Claims-based authentication and not classic...I'm assuming that's already the case).
There are numerous tutorials about the steps required to configure FBA, which generally boil down to:
* Creating the ASP.NET membership and role providers
* Modifying the web.config files for the FBA web application, central administration, and SharePoint's security token service
* Configuring users
* Setting up the appropriate authentication provider in central administration and testing
There is a good tutorial that uses the ASP.NET SQL Membership and Role providers [here](http://msdn.microsoft.com/en-us/library/gg252020%28v=office.14%29.aspx), but you can substitute your own providers.
Out of curiosity, how would you plan to redirect users based on URL if you don't want to extend the web application? The whole point of mixed mode authentication is that the same web application URL can support multiple authentication providers. This helps when it comes to things like search (i.e., search has to use an NTLM account for crawling, and with the same URLs in place, FBA users with appropriate permissions can more readily access this content).
If you did want to do any special redirection, you would need to create your own **custom sign in page** and specify it in central administration for the web application where you are configuring authentication providers. An example that does this based on client IP address can be found [here](http://www.orbitone.com/en/blog/archive/2010/06/23/sharepoint-2010-mixed-authentication-automatic-login.aspx). | There could be a problem if you do not extend. If you ever want to shut off windows authentication, the site collection will not crawl correctly. Having windows authentication on for us causes problems, because users will go to another site login with active directory and come to our site and be logged in with active directory instead of FBA, then their permissions are screwed up and they end up having multiple profiles on the site. |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | That usually relies on the writer's style and skill…
Look how Iris Murdoch introduces great and irrelevant details of menus and cooking, when it wasn't in any way necessary even to mention that anyone was eating.
Notice when Robert A Heinlein lists every move in a game of mental chess which has no real effect on the story or - more than once - describes every action involved in checking whether a vintage car might be immediately ready for the road, rather than simply pressing the starter!
See whether Allan W. Eckert had any need to describe the driver's day, breakfast or family life when he could simply have stated that a truck smashed into his hero's car.
If the Question persists, stick to what detail is actually necessary.
"He drew a gun and shot the man dead" is fine in itself.
"He pulled out a pistol and plugged the lead 'til the man was dead" is more stylish and whether it's more helpful is a matter of choice, isn't it?
"He hauled his tried and trusted, nine-shot Mauser .455 Parabellum from the tooled and monogrammed leather holster behind his hip, raised the silver-plated weapon in a two-handed grip and took slow and careful aim then gently squeezed off a single shot that dropped the victim in his tracks" is at best highly questionable, and probably a lot more pretentious than practical. | Pick your idea first.
What is it? And how do you want to approach it?
All styles are fine as long as the target audience is satisfied. You don't want to bore airport novel readers with a lot of detail, **and** you don't want to ruffle feathers by writing an outline for a research paper.
**Indiana Jones** was an entertaining swashbuckler flick - to develop its entertainment value, any idea must lose excess detail. The focus must lie on the spectacle - jumps, ducks, sways, headshots, near fall-to-death misses.
It is not easy to get it right in one go. This is true for everyone, even experienced writers. Every major piece undergoes a rewrite. So - get through the first draft. Then read your own work like a critic and decide for yourself. Let the thought that you spent months, possibly years, on the manuscript not bother you while you analyse.
A typical way to lower the number of rewrites is to use the **outlining method**. Plot your tale before you write it.
A high level overview before the grunt work helps make preemptive changes. When you realise you have the two main characters talking at a table and drinking for a whole chapter, you will know your mistake.
Wish you good luck with your book! |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | [Daniel's answer](https://writers.stackexchange.com/a/26214/18298) is good, but I have an additional "yardstick" which may be helpful:
Part of art, of *any* art form, is inviting the *audience* to contribute.
It's even been said this is what *makes* it art: A return contribution is invited. You supply something yourself as an audience or reader, rather than just having the words flow in at you without you yourself participating.
If you describe every tiny detail to such a degree that *nothing* is left to the imagination, you wind up with a court deposition, not a story. There's not going to be a great deal of interest, because the reader will not be invited to *participate* and use his imagination to fill in gaps.
If you consider carefully, you'll likely find that any story which really "pulled you in" was one in which you were actively participating in imagining the details and filling in "how it would have been," rather than one in which you were slavishly noting every last exhaustive detail directly from the author's description.
Other things besides physical descriptions can be left to the imagination too, of course. You need to provide enough detail to spur your reader's imagination to fill in the rest.
---
Something which goes along with this:
Don't use description to make your reader's imagination *wrong.*
If you introduce a character and keep him doing things and saying things for several chapters before you happen to mention that he has very dark skin and pale blonde hair, you are very likely to throw your reader out of the story. She will have come up with her *own* mental picture of how this character looks by then, and the description, coming so late, will make her feel that she "got it wrong." Really, the author is at fault for such a jolt.
---
Physical descriptions are a good thing to include, just don't stop the flow of the story to include them. Don't stop the *action.* It's not *vital* that your readers envision every detail just exactly the same way you do. Include enough that they get a colorful (vivid, evocative) picture of the events you depict—fully fleshed out by their own imagination, which you've coaxed into action with your masterful use of descriptive words. | Pick your idea first.
What is it? And how do you want to approach it?
All styles are fine as long as the target audience is satisfied. You don't want to bore airport novel readers with a lot of detail, **and** you don't want to ruffle feathers by writing an outline for a research paper.
**Indiana Jones** was an entertaining swashbuckler flick - to develop its entertainment value, any idea must lose excess detail. The focus must lie on the spectacle - jumps, ducks, sways, headshots, near fall-to-death misses.
It is not easy to get it right in one go. This is true for everyone, even experienced writers. Every major piece undergoes a rewrite. So - get through the first draft. Then read your own work like a critic and decide for yourself. Let the thought that you spent months, possibly years, on the manuscript not bother you while you analyse.
A typical way to lower the number of rewrites is to use the **outlining method**. Plot your tale before you write it.
A high level overview before the grunt work helps make preemptive changes. When you realise you have the two main characters talking at a table and drinking for a whole chapter, you will know your mistake.
Wish you good luck with your book! |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | You said it yourself. When the reader cannot concentrate on the story because there are so many adjectives and adverbs, and other details and flourishes. Get other people to read your writing, and they will be able to easily comment on this.
You are also falling into having too much detail if every other word is an adjective or adverb. If you're describing every noun or verb with them, **stop it.** It's really bad and will lead to the thing I said above. Here's an example:
>
> I furiously knocked on the brown oak door, and impatiently waited for my annoying brother to finally arrive.
>
>
>
That sentence is a little extreme but I have seen things like it in the past. There are many things which would be implied by the story (even though we don't have a 'story' in this example). We can pick out some unnecessary descriptions:
* The brother is annoying. We don't need to describe that because the protagonist would only be furiously knocking on the door if the brother had been doing something bad/annoying.
* The brown oak door. This is really unnecessary. I don't need to be reminded of what a door looks like, it's one of those things you can leave for the reader to imagine. However, if there's a special door, you can describe it. For example, a door with spikes on.
* Impatiently and finally. Impatiently is already implied, and if you wanted to further show this, you could perhaps write another sentence about him doing something impatient. Finally is just completely unnecessary and you don't really need it. It adds an extra not-needed adverb to the sentence.
I think that the amount of detail depends on the author though. It's very difficult to know if you're using too little or too much. So what I would advise is: use your peers to your advantage! Go onto a site like [Critique Circle](http://www.critiquecircle.com/) and get it critiqued. | To answer this question you have to consider the purpose of detail. The purpose of detail is to refine the picture in the reader's head. Readers pull images from their own stock of experiences to build a picture of what they are reading. Each detail you add refines the selection of images they make. If you say "bus" they select an image of the kind of bus they are most familiar with. If you say "red double-decker bus" they probably select an image of a London bus, unless they live in another city with red double-decker buses.
The image in the reader's head will probably never match the image in your head perfectly, unless you have had the exact same experience. The question is, how close do I need the image in the reader's head to be to the image in my head for them to receive the story, its mood and texture as well as its plot, in the way I intend. You add detail until you think the reader's image will be close enough to your own for story purposes.
I disagree with those who say you should leave something to the reader's imagination. That's moot. It all comes from the reader's imagination. You job is to direct that imagination into the right channels so that the reader receives the experience you are attempting to create.
A closely related question is, how closely do you paint each scene and each object in a scene. The more you refine an image, the more important you make that image. Don't make any image more important in a scene than it is in the story, or you will divert the reader's attention away from what matters in the story.
Finally, it is really more about finding the right detail than it is about the amount of detail. Think of it like a database query on the user's stock of experiences. Certain details will pull up certain images whole and intact. A swastika armband may be the only detail you need to pull up the image of a Nazi soldier, for instance. This is what is often called the telling detail, and finding the telling detail is far more important than how much detail you provide. The telling detail can not only pull out a particular object but the entire scene, the entire time and place to which that object belongs. Thus the red double-decker evokes London, the swastika armband evokes Nazi Germany.
Finally, be wary of details that seem contradictory or are hard to integrate. Adding one more term to a database query can turn it from retrieving a very precise image to returning no data at all. |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | To answer this question you have to consider the purpose of detail. The purpose of detail is to refine the picture in the reader's head. Readers pull images from their own stock of experiences to build a picture of what they are reading. Each detail you add refines the selection of images they make. If you say "bus" they select an image of the kind of bus they are most familiar with. If you say "red double-decker bus" they probably select an image of a London bus, unless they live in another city with red double-decker buses.
The image in the reader's head will probably never match the image in your head perfectly, unless you have had the exact same experience. The question is, how close do I need the image in the reader's head to be to the image in my head for them to receive the story, its mood and texture as well as its plot, in the way I intend. You add detail until you think the reader's image will be close enough to your own for story purposes.
I disagree with those who say you should leave something to the reader's imagination. That's moot. It all comes from the reader's imagination. You job is to direct that imagination into the right channels so that the reader receives the experience you are attempting to create.
A closely related question is, how closely do you paint each scene and each object in a scene. The more you refine an image, the more important you make that image. Don't make any image more important in a scene than it is in the story, or you will divert the reader's attention away from what matters in the story.
Finally, it is really more about finding the right detail than it is about the amount of detail. Think of it like a database query on the user's stock of experiences. Certain details will pull up certain images whole and intact. A swastika armband may be the only detail you need to pull up the image of a Nazi soldier, for instance. This is what is often called the telling detail, and finding the telling detail is far more important than how much detail you provide. The telling detail can not only pull out a particular object but the entire scene, the entire time and place to which that object belongs. Thus the red double-decker evokes London, the swastika armband evokes Nazi Germany.
Finally, be wary of details that seem contradictory or are hard to integrate. Adding one more term to a database query can turn it from retrieving a very precise image to returning no data at all. | Pick your idea first.
What is it? And how do you want to approach it?
All styles are fine as long as the target audience is satisfied. You don't want to bore airport novel readers with a lot of detail, **and** you don't want to ruffle feathers by writing an outline for a research paper.
**Indiana Jones** was an entertaining swashbuckler flick - to develop its entertainment value, any idea must lose excess detail. The focus must lie on the spectacle - jumps, ducks, sways, headshots, near fall-to-death misses.
It is not easy to get it right in one go. This is true for everyone, even experienced writers. Every major piece undergoes a rewrite. So - get through the first draft. Then read your own work like a critic and decide for yourself. Let the thought that you spent months, possibly years, on the manuscript not bother you while you analyse.
A typical way to lower the number of rewrites is to use the **outlining method**. Plot your tale before you write it.
A high level overview before the grunt work helps make preemptive changes. When you realise you have the two main characters talking at a table and drinking for a whole chapter, you will know your mistake.
Wish you good luck with your book! |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | While the existing answers are helpful, they don't address what seems to me the crux of this question. The answers will change depending on what you are writing, for which audience and what effect do you hope to achieve?
For example, I primarily write journalism. The idea is to engage the reader quickly and carry them through to the end of the article. As a general rule it is good to keep descriptive writing to a minimum since it reduces the punchiness and impact of the work. Better instead to pluck a few well-chosen metaphors to help the reader relate what you're describing quickly and easily to their own experience.
Yet even this is subject to change depending on circumstance. A print article is generally subject to a draconian word count and you must be even more sparing with your descriptions. On the other hand if the feature is emotive in nature or is describing an external narrative, you will need to spend some time scene-setting.
Contrast this to the opening sentence of Cormac McCarthy's novel Suttree.
>
> Dear friend now in the dusty clockless hours of the town when the
> streets lie black and steaming in the wake of the watertrucks and now
> when the drunk and the homeless have washed up in the lee of walls in
> alleys or abandoned lots and cats go forth highshouldered and lean in
> the grim perimeters about, now in these sootblacked brick or cobbled
> corridors where lightwire shadows make a gothic harp of cellar doors
> no soul shall walk save you.
>
>
>
This is grandiose to the point of impenetrability. If I tried anything like that, my editors would tear it apart and never employ me again. It's also way beyond the level other answers are suggesting you should take descriptive writing. Yet I find it an extraordinary scene-setter, brilliant in its eloquence. It works because it's well structured and because in the context of the work of a heavyweight novelist, we might expect such constructions.
In summary: your yardstick for measure whether you've got "too much" description depends entirely on the effect you're trying to achieve and your skill at building descriptions. | Pick your idea first.
What is it? And how do you want to approach it?
All styles are fine as long as the target audience is satisfied. You don't want to bore airport novel readers with a lot of detail, **and** you don't want to ruffle feathers by writing an outline for a research paper.
**Indiana Jones** was an entertaining swashbuckler flick - to develop its entertainment value, any idea must lose excess detail. The focus must lie on the spectacle - jumps, ducks, sways, headshots, near fall-to-death misses.
It is not easy to get it right in one go. This is true for everyone, even experienced writers. Every major piece undergoes a rewrite. So - get through the first draft. Then read your own work like a critic and decide for yourself. Let the thought that you spent months, possibly years, on the manuscript not bother you while you analyse.
A typical way to lower the number of rewrites is to use the **outlining method**. Plot your tale before you write it.
A high level overview before the grunt work helps make preemptive changes. When you realise you have the two main characters talking at a table and drinking for a whole chapter, you will know your mistake.
Wish you good luck with your book! |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | Most of the answers on here are adequate, however, I do not feel that they get straight to the point.
How much detail is too much?
============================
>
> I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about.
>
>
>
You have answered your own question:
**Q**: How much detail is too much?
**A**: When the reader gets a little bored or distracted and forgets what the actual story is talking about.
The details in a "fully expressed medium of text" (that is, a sentence, paragraph, article, book, or voluminous/episodic series) greatly influence attention. The center of attention is *the focus*.
*Superfluous details* are details that divert attention away from the focus. Consider the following:
>
> I was dropped off at the usual bus stop that I attend every morning. It is a short stretch of concrete road with green signs, and four houses. There are two houses on each side. Each house is white. The lawns varied in shades of green and brown (it was early fall). When the bus finally arrived, I hopped on. Silence was in the cold air of the bus as students stared at their phones and closed their minds off from the real world to escape into the fantasy of the internet.
>
>
>
The focus of this paragraph is getting on the bus, but yet, all the detail is focusing on the surrounding environment of the bus stop, before abruptly transitioning to hopping on the bus which appeared out of no where.
*Necessary details* are consistent with the focus. Consider the following:
>
> I came to this large, two-story house with overarching balconies and elegant columns. It was old—very old. I burst open the dusty, wooden double-doors that entered into the house. The room was dark, and had a musty, century-old odor to it. The black and white checkered tile pattern on the floor was heavily worn and coarse. The chandelier dangled askew. This was, no doubt, a dance hall, which told the story of a time long forgotten, when people twirled and danced to a merry tune.
>
>
>
The details in this paragraph dictate that the focus is an old house which had many ballroom-style dances. Every detail describes the age of this house, and the purpose is to give imagery of what the house looks like, and what the ambient atmosphere projects. Without these details, this would be a dull paragraph, and the actual *lack* of detail would bore and distract.
---
Detail is of course only one element of influence for the audience's attention, but it is clearly displayed that it does have a great impact on attention. The detail determines the focus,
so how much detail is too much?
===============================
*When the details shift attention away from the center of attention.* | While the existing answers are helpful, they don't address what seems to me the crux of this question. The answers will change depending on what you are writing, for which audience and what effect do you hope to achieve?
For example, I primarily write journalism. The idea is to engage the reader quickly and carry them through to the end of the article. As a general rule it is good to keep descriptive writing to a minimum since it reduces the punchiness and impact of the work. Better instead to pluck a few well-chosen metaphors to help the reader relate what you're describing quickly and easily to their own experience.
Yet even this is subject to change depending on circumstance. A print article is generally subject to a draconian word count and you must be even more sparing with your descriptions. On the other hand if the feature is emotive in nature or is describing an external narrative, you will need to spend some time scene-setting.
Contrast this to the opening sentence of Cormac McCarthy's novel Suttree.
>
> Dear friend now in the dusty clockless hours of the town when the
> streets lie black and steaming in the wake of the watertrucks and now
> when the drunk and the homeless have washed up in the lee of walls in
> alleys or abandoned lots and cats go forth highshouldered and lean in
> the grim perimeters about, now in these sootblacked brick or cobbled
> corridors where lightwire shadows make a gothic harp of cellar doors
> no soul shall walk save you.
>
>
>
This is grandiose to the point of impenetrability. If I tried anything like that, my editors would tear it apart and never employ me again. It's also way beyond the level other answers are suggesting you should take descriptive writing. Yet I find it an extraordinary scene-setter, brilliant in its eloquence. It works because it's well structured and because in the context of the work of a heavyweight novelist, we might expect such constructions.
In summary: your yardstick for measure whether you've got "too much" description depends entirely on the effect you're trying to achieve and your skill at building descriptions. |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | [Daniel's answer](https://writers.stackexchange.com/a/26214/18298) is good, but I have an additional "yardstick" which may be helpful:
Part of art, of *any* art form, is inviting the *audience* to contribute.
It's even been said this is what *makes* it art: A return contribution is invited. You supply something yourself as an audience or reader, rather than just having the words flow in at you without you yourself participating.
If you describe every tiny detail to such a degree that *nothing* is left to the imagination, you wind up with a court deposition, not a story. There's not going to be a great deal of interest, because the reader will not be invited to *participate* and use his imagination to fill in gaps.
If you consider carefully, you'll likely find that any story which really "pulled you in" was one in which you were actively participating in imagining the details and filling in "how it would have been," rather than one in which you were slavishly noting every last exhaustive detail directly from the author's description.
Other things besides physical descriptions can be left to the imagination too, of course. You need to provide enough detail to spur your reader's imagination to fill in the rest.
---
Something which goes along with this:
Don't use description to make your reader's imagination *wrong.*
If you introduce a character and keep him doing things and saying things for several chapters before you happen to mention that he has very dark skin and pale blonde hair, you are very likely to throw your reader out of the story. She will have come up with her *own* mental picture of how this character looks by then, and the description, coming so late, will make her feel that she "got it wrong." Really, the author is at fault for such a jolt.
---
Physical descriptions are a good thing to include, just don't stop the flow of the story to include them. Don't stop the *action.* It's not *vital* that your readers envision every detail just exactly the same way you do. Include enough that they get a colorful (vivid, evocative) picture of the events you depict—fully fleshed out by their own imagination, which you've coaxed into action with your masterful use of descriptive words. | To answer this question you have to consider the purpose of detail. The purpose of detail is to refine the picture in the reader's head. Readers pull images from their own stock of experiences to build a picture of what they are reading. Each detail you add refines the selection of images they make. If you say "bus" they select an image of the kind of bus they are most familiar with. If you say "red double-decker bus" they probably select an image of a London bus, unless they live in another city with red double-decker buses.
The image in the reader's head will probably never match the image in your head perfectly, unless you have had the exact same experience. The question is, how close do I need the image in the reader's head to be to the image in my head for them to receive the story, its mood and texture as well as its plot, in the way I intend. You add detail until you think the reader's image will be close enough to your own for story purposes.
I disagree with those who say you should leave something to the reader's imagination. That's moot. It all comes from the reader's imagination. You job is to direct that imagination into the right channels so that the reader receives the experience you are attempting to create.
A closely related question is, how closely do you paint each scene and each object in a scene. The more you refine an image, the more important you make that image. Don't make any image more important in a scene than it is in the story, or you will divert the reader's attention away from what matters in the story.
Finally, it is really more about finding the right detail than it is about the amount of detail. Think of it like a database query on the user's stock of experiences. Certain details will pull up certain images whole and intact. A swastika armband may be the only detail you need to pull up the image of a Nazi soldier, for instance. This is what is often called the telling detail, and finding the telling detail is far more important than how much detail you provide. The telling detail can not only pull out a particular object but the entire scene, the entire time and place to which that object belongs. Thus the red double-decker evokes London, the swastika armband evokes Nazi Germany.
Finally, be wary of details that seem contradictory or are hard to integrate. Adding one more term to a database query can turn it from retrieving a very precise image to returning no data at all. |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | You said it yourself. When the reader cannot concentrate on the story because there are so many adjectives and adverbs, and other details and flourishes. Get other people to read your writing, and they will be able to easily comment on this.
You are also falling into having too much detail if every other word is an adjective or adverb. If you're describing every noun or verb with them, **stop it.** It's really bad and will lead to the thing I said above. Here's an example:
>
> I furiously knocked on the brown oak door, and impatiently waited for my annoying brother to finally arrive.
>
>
>
That sentence is a little extreme but I have seen things like it in the past. There are many things which would be implied by the story (even though we don't have a 'story' in this example). We can pick out some unnecessary descriptions:
* The brother is annoying. We don't need to describe that because the protagonist would only be furiously knocking on the door if the brother had been doing something bad/annoying.
* The brown oak door. This is really unnecessary. I don't need to be reminded of what a door looks like, it's one of those things you can leave for the reader to imagine. However, if there's a special door, you can describe it. For example, a door with spikes on.
* Impatiently and finally. Impatiently is already implied, and if you wanted to further show this, you could perhaps write another sentence about him doing something impatient. Finally is just completely unnecessary and you don't really need it. It adds an extra not-needed adverb to the sentence.
I think that the amount of detail depends on the author though. It's very difficult to know if you're using too little or too much. So what I would advise is: use your peers to your advantage! Go onto a site like [Critique Circle](http://www.critiquecircle.com/) and get it critiqued. | While the existing answers are helpful, they don't address what seems to me the crux of this question. The answers will change depending on what you are writing, for which audience and what effect do you hope to achieve?
For example, I primarily write journalism. The idea is to engage the reader quickly and carry them through to the end of the article. As a general rule it is good to keep descriptive writing to a minimum since it reduces the punchiness and impact of the work. Better instead to pluck a few well-chosen metaphors to help the reader relate what you're describing quickly and easily to their own experience.
Yet even this is subject to change depending on circumstance. A print article is generally subject to a draconian word count and you must be even more sparing with your descriptions. On the other hand if the feature is emotive in nature or is describing an external narrative, you will need to spend some time scene-setting.
Contrast this to the opening sentence of Cormac McCarthy's novel Suttree.
>
> Dear friend now in the dusty clockless hours of the town when the
> streets lie black and steaming in the wake of the watertrucks and now
> when the drunk and the homeless have washed up in the lee of walls in
> alleys or abandoned lots and cats go forth highshouldered and lean in
> the grim perimeters about, now in these sootblacked brick or cobbled
> corridors where lightwire shadows make a gothic harp of cellar doors
> no soul shall walk save you.
>
>
>
This is grandiose to the point of impenetrability. If I tried anything like that, my editors would tear it apart and never employ me again. It's also way beyond the level other answers are suggesting you should take descriptive writing. Yet I find it an extraordinary scene-setter, brilliant in its eloquence. It works because it's well structured and because in the context of the work of a heavyweight novelist, we might expect such constructions.
In summary: your yardstick for measure whether you've got "too much" description depends entirely on the effect you're trying to achieve and your skill at building descriptions. |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | To answer this question you have to consider the purpose of detail. The purpose of detail is to refine the picture in the reader's head. Readers pull images from their own stock of experiences to build a picture of what they are reading. Each detail you add refines the selection of images they make. If you say "bus" they select an image of the kind of bus they are most familiar with. If you say "red double-decker bus" they probably select an image of a London bus, unless they live in another city with red double-decker buses.
The image in the reader's head will probably never match the image in your head perfectly, unless you have had the exact same experience. The question is, how close do I need the image in the reader's head to be to the image in my head for them to receive the story, its mood and texture as well as its plot, in the way I intend. You add detail until you think the reader's image will be close enough to your own for story purposes.
I disagree with those who say you should leave something to the reader's imagination. That's moot. It all comes from the reader's imagination. You job is to direct that imagination into the right channels so that the reader receives the experience you are attempting to create.
A closely related question is, how closely do you paint each scene and each object in a scene. The more you refine an image, the more important you make that image. Don't make any image more important in a scene than it is in the story, or you will divert the reader's attention away from what matters in the story.
Finally, it is really more about finding the right detail than it is about the amount of detail. Think of it like a database query on the user's stock of experiences. Certain details will pull up certain images whole and intact. A swastika armband may be the only detail you need to pull up the image of a Nazi soldier, for instance. This is what is often called the telling detail, and finding the telling detail is far more important than how much detail you provide. The telling detail can not only pull out a particular object but the entire scene, the entire time and place to which that object belongs. Thus the red double-decker evokes London, the swastika armband evokes Nazi Germany.
Finally, be wary of details that seem contradictory or are hard to integrate. Adding one more term to a database query can turn it from retrieving a very precise image to returning no data at all. | That usually relies on the writer's style and skill…
Look how Iris Murdoch introduces great and irrelevant details of menus and cooking, when it wasn't in any way necessary even to mention that anyone was eating.
Notice when Robert A Heinlein lists every move in a game of mental chess which has no real effect on the story or - more than once - describes every action involved in checking whether a vintage car might be immediately ready for the road, rather than simply pressing the starter!
See whether Allan W. Eckert had any need to describe the driver's day, breakfast or family life when he could simply have stated that a truck smashed into his hero's car.
If the Question persists, stick to what detail is actually necessary.
"He drew a gun and shot the man dead" is fine in itself.
"He pulled out a pistol and plugged the lead 'til the man was dead" is more stylish and whether it's more helpful is a matter of choice, isn't it?
"He hauled his tried and trusted, nine-shot Mauser .455 Parabellum from the tooled and monogrammed leather holster behind his hip, raised the silver-plated weapon in a two-handed grip and took slow and careful aim then gently squeezed off a single shot that dropped the victim in his tracks" is at best highly questionable, and probably a lot more pretentious than practical. |
26,211 | I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about. How do I know whether I am using too much, not enough, or the right amount of detail? | 2017/01/23 | [
"https://writers.stackexchange.com/questions/26211",
"https://writers.stackexchange.com",
"https://writers.stackexchange.com/users/22630/"
] | Most of the answers on here are adequate, however, I do not feel that they get straight to the point.
How much detail is too much?
============================
>
> I've read a few amateur stories online and sometimes the author will include so much detail that the reader gets a little bored or distracted and forgets what the actual story is talking about.
>
>
>
You have answered your own question:
**Q**: How much detail is too much?
**A**: When the reader gets a little bored or distracted and forgets what the actual story is talking about.
The details in a "fully expressed medium of text" (that is, a sentence, paragraph, article, book, or voluminous/episodic series) greatly influence attention. The center of attention is *the focus*.
*Superfluous details* are details that divert attention away from the focus. Consider the following:
>
> I was dropped off at the usual bus stop that I attend every morning. It is a short stretch of concrete road with green signs, and four houses. There are two houses on each side. Each house is white. The lawns varied in shades of green and brown (it was early fall). When the bus finally arrived, I hopped on. Silence was in the cold air of the bus as students stared at their phones and closed their minds off from the real world to escape into the fantasy of the internet.
>
>
>
The focus of this paragraph is getting on the bus, but yet, all the detail is focusing on the surrounding environment of the bus stop, before abruptly transitioning to hopping on the bus which appeared out of no where.
*Necessary details* are consistent with the focus. Consider the following:
>
> I came to this large, two-story house with overarching balconies and elegant columns. It was old—very old. I burst open the dusty, wooden double-doors that entered into the house. The room was dark, and had a musty, century-old odor to it. The black and white checkered tile pattern on the floor was heavily worn and coarse. The chandelier dangled askew. This was, no doubt, a dance hall, which told the story of a time long forgotten, when people twirled and danced to a merry tune.
>
>
>
The details in this paragraph dictate that the focus is an old house which had many ballroom-style dances. Every detail describes the age of this house, and the purpose is to give imagery of what the house looks like, and what the ambient atmosphere projects. Without these details, this would be a dull paragraph, and the actual *lack* of detail would bore and distract.
---
Detail is of course only one element of influence for the audience's attention, but it is clearly displayed that it does have a great impact on attention. The detail determines the focus,
so how much detail is too much?
===============================
*When the details shift attention away from the center of attention.* | That usually relies on the writer's style and skill…
Look how Iris Murdoch introduces great and irrelevant details of menus and cooking, when it wasn't in any way necessary even to mention that anyone was eating.
Notice when Robert A Heinlein lists every move in a game of mental chess which has no real effect on the story or - more than once - describes every action involved in checking whether a vintage car might be immediately ready for the road, rather than simply pressing the starter!
See whether Allan W. Eckert had any need to describe the driver's day, breakfast or family life when he could simply have stated that a truck smashed into his hero's car.
If the Question persists, stick to what detail is actually necessary.
"He drew a gun and shot the man dead" is fine in itself.
"He pulled out a pistol and plugged the lead 'til the man was dead" is more stylish and whether it's more helpful is a matter of choice, isn't it?
"He hauled his tried and trusted, nine-shot Mauser .455 Parabellum from the tooled and monogrammed leather holster behind his hip, raised the silver-plated weapon in a two-handed grip and took slow and careful aim then gently squeezed off a single shot that dropped the victim in his tracks" is at best highly questionable, and probably a lot more pretentious than practical. |
25,491 | I'm having a debate about how bright Martian nights would be, in terms of both the sky itself and ground illumination. [This](https://astronomy.stackexchange.com/questions/10220/mars-night-sky-how-many-stars-visible) answer seems to indicate that the stars would be only dimly visible, and wouldn't provide enough light to see by. However, the question remains of how much illumination the moons would provide. I've seen it said that Deimos would appear about as bright as Venus does from Earth, and that Phobos would be about twenty times brighter, but it's not clear to me how that compares to e.g. our own moon's illumination. So how bright would it look? Would it be enough to see by? | 2018/03/14 | [
"https://astronomy.stackexchange.com/questions/25491",
"https://astronomy.stackexchange.com",
"https://astronomy.stackexchange.com/users/22197/"
] | Taking Mars' average distance from the sun of 1.52 AU, the sun would be 43% as bright.
Phobos has an [albedo of about 0.071](https://en.wikipedia.org/wiki/Phobos_(moon)) which is pretty dark. Darker than the Moon with an average albedo of about 0.12, so it reflects about 59% as well as the Moon does. That gives it a brightness to area of just over 25% the brightness of the moon.
Phobos is an odd shape, about 27x22x18 km. Averaging that out to 22, then Phobos is 1/158 the diameter of the Moon, but it's closer to Mars' surface. about 5,986 km, that's about 63.5 times closer than the Moon is to the surface of the Earth.
Working out the numbers, the size of phobos in the Martian sky would be on average 63.5/158 or 40% the diameter, or 16% the size of Earth's Moon from Earth. Multiply that by 25% the brightness to area and that's just 4% the brightness of a full moon. That would be peak brightness (and if you want to fuss about Mars' Perihelion and say 5% the brightness of a full moon, fair enough, but lets not get ahead of ourselves).
Brightness of our Moon varies depending how good a reflector it's surface is, and how much of the surface is in shadow. The Moon is particularly cratered so [a half moon is significantly less than half as bright as a full moon](http://www.chicagotribune.com/news/weather/ct-wea-0404-asktom-20150403-column.html). Phobos is so close to Mars that from the surface of Phobos, Mars takes up about 40 degrees of arc in the sky. That casts a huge shadow, so there's no such thing, from Mars, as a full Phobos. As Phobos approaches full, it enters Mars' shadow and it's brightness drops significantly (whether it turns red like a blood moon or just vanishes - I'm not sure, perhaps that's best for another question). But Phobos never becomes full, it gets a bit over 3/4s, then it enters Mars' shadow.
"Enough to see" is a tough question, because sight depends on not just the light source but the reflectivity of your surroundings and there's some variation in how well individuals can see in the dark and, obviously, on how clear the night sky is on Mars on that particular night. *I think 3%-4% of the brightness of a 3/4 moon would be pushing the limit though and probably not bright enough to see for the most people*. **BUT** reading the comments, and reading the very cool Venus shadow article in the questions comments, my assumption might be wrong. Limited sight might/(should?) be possible with some recognition of shadows and shapes. | Phobos's orbit is, like Mars' axis, inclined to Mars orbit by 25 degrees, so at greatest offset, I figure that Phobos is likely to be offset from the plane of Mars orbit by more than Mars' radius. Even at a periapsis distance of 9234km,
9234km\*sine(25 degrees)=3902 km
is more than Mars radius of 3390 km.
So in winter and summer, there should be full Phobos. |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | I think turning the image into a [NSFW] tagged link is a good compromise. That way people who don't want to view it can easily avoid it, while those who do are not hindered much. (I'd prefer spoiler tags, but the SE implementation of spoilers doesn't support spoilering images)
As a guideline for which images to spoiler I'd use: "Many users wouldn't be comfortable viewing that image in a public place, such as work."
I wouldn't base this this on TV guidelines, or explicitly forbid nudity or violence.
(Cross post from <https://meta.stackexchange.com/a/124498/152255>) | I support the [NSFW] tag. Some considerations:
* Workplaces have weird rules that we cannot change. A [NSFW] tag lets you know that you probably shouldn't open the link at the office.
* Note that you probably shouldn't browse this site at the office *anyway*; do so at your own risk. I do read it on my lunch break, and I know the risks involved.
* About the children argument: a lot of SF & Fantasy is for adults. This website is meant for adults, and children are not allowed. If you are so concerned that your kids might accidentally read it and be traumatized by the sight of a naked female back, then install an internet filter.
* The image itself is very tame. Like they say, nothing you wouldn't see in a soap commercial.
Let's not turn this into a prudish website, people! |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | I don't see a problem with that question per se, and I'm fairly liberal about such things but I wouldn't want someone at work to look over my shoulder and see that picture on my screen. It seems to me this question was worded in a somewhat provocative way (perhaps not intentionally). I think if we change the title to be somewhat more work-appropriate and change the picture to a link it's just fine. Also, note none of the comments even hint it may be too adult for this site.
And when I asked [a question along similar lines on outdoors meta](https://outdoors.meta.stackexchange.com/a/109/18), Robert Cartaino (the Director of Community Development for the Stack Exchange Network) had this to say:
>
> When exploring the appropriateness of a question, there are a few bars the question should pass:
>
>
> * Is the question being asked in good faith, and not just an excuse to post a tantalizing title to "test the fence" of what would be allowed?
> * Is the question itself adding to the substance of the site (i.e. Is this an intriguing and challenging question about the subject of "The Great Outdoors")?
> * Are the experts here best-equipped to answer your question (or is your question just obliquely- or tangentially-related to the subject)?
>
>
> | The image is from the episode, isn't it?
Is this site's policy actually going to be more limiting than the standards the FCC applies to primetime broadcast television?
A bare female back is hardly "adult content". |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | I don't see a problem with that question per se, and I'm fairly liberal about such things but I wouldn't want someone at work to look over my shoulder and see that picture on my screen. It seems to me this question was worded in a somewhat provocative way (perhaps not intentionally). I think if we change the title to be somewhat more work-appropriate and change the picture to a link it's just fine. Also, note none of the comments even hint it may be too adult for this site.
And when I asked [a question along similar lines on outdoors meta](https://outdoors.meta.stackexchange.com/a/109/18), Robert Cartaino (the Director of Community Development for the Stack Exchange Network) had this to say:
>
> When exploring the appropriateness of a question, there are a few bars the question should pass:
>
>
> * Is the question being asked in good faith, and not just an excuse to post a tantalizing title to "test the fence" of what would be allowed?
> * Is the question itself adding to the substance of the site (i.e. Is this an intriguing and challenging question about the subject of "The Great Outdoors")?
> * Are the experts here best-equipped to answer your question (or is your question just obliquely- or tangentially-related to the subject)?
>
>
> | I'd say that if it's something that *could be* considered offensive, whether adult content, foul language, or blatant flamebait, it should be disallowed. I shouldn't have to worry about my wife or boss seeing offensive stuff on my screen or in server logs. Period.
I fail to see why this is even an issue. If you want to post NSFW stuff, use some other site. This is a *professional, work oriented* site. Not an NSFW site. |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | The image is from the episode, isn't it?
Is this site's policy actually going to be more limiting than the standards the FCC applies to primetime broadcast television?
A bare female back is hardly "adult content". | I don't see how work is at all relevant here, unless your work is specifically related to science fiction and fantasy (in which case, it seems likely to me that this image would be considered appropriate).
If my employees were meant to stick to working during their work times (i.e. the traditional viewpoint), then the background image for scifi.se immediately tells me, whatever question they are looking at, that they are goofing off. It doesn't matter what content is in the question and/or answer.
If I'm tolerant of my employees occasionally doing non-work-related things during their work times (i.e. the modern viewpoint), then a screenshot from a PG TV show is perfectly acceptable.
The terms and conditions of the site specify that you must be 13 or older to use it. It seems to me that posters (and editors) and use their own judgement as to whether content is appropriate for a 13-year-old (in particular, 13-year-olds that are likely to be using this site). |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | The image is from the episode, isn't it?
Is this site's policy actually going to be more limiting than the standards the FCC applies to primetime broadcast television?
A bare female back is hardly "adult content". | I support the [NSFW] tag. Some considerations:
* Workplaces have weird rules that we cannot change. A [NSFW] tag lets you know that you probably shouldn't open the link at the office.
* Note that you probably shouldn't browse this site at the office *anyway*; do so at your own risk. I do read it on my lunch break, and I know the risks involved.
* About the children argument: a lot of SF & Fantasy is for adults. This website is meant for adults, and children are not allowed. If you are so concerned that your kids might accidentally read it and be traumatized by the sight of a naked female back, then install an internet filter.
* The image itself is very tame. Like they say, nothing you wouldn't see in a soap commercial.
Let's not turn this into a prudish website, people! |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | I don't see a problem with that question per se, and I'm fairly liberal about such things but I wouldn't want someone at work to look over my shoulder and see that picture on my screen. It seems to me this question was worded in a somewhat provocative way (perhaps not intentionally). I think if we change the title to be somewhat more work-appropriate and change the picture to a link it's just fine. Also, note none of the comments even hint it may be too adult for this site.
And when I asked [a question along similar lines on outdoors meta](https://outdoors.meta.stackexchange.com/a/109/18), Robert Cartaino (the Director of Community Development for the Stack Exchange Network) had this to say:
>
> When exploring the appropriateness of a question, there are a few bars the question should pass:
>
>
> * Is the question being asked in good faith, and not just an excuse to post a tantalizing title to "test the fence" of what would be allowed?
> * Is the question itself adding to the substance of the site (i.e. Is this an intriguing and challenging question about the subject of "The Great Outdoors")?
> * Are the experts here best-equipped to answer your question (or is your question just obliquely- or tangentially-related to the subject)?
>
>
> | Since Sachin posted this question (or its derivative) on Meta.SO, I will take the liberty of re-posting the [answer](https://meta.stackexchange.com/a/124340/119280) from MSO moderator Robert Harvey (sans a really nice pic):
>
> **If you wouldn't want to have to explain to your boss why part of Jolene Blalock's bare ass is on your screen, you probably shouldn't post it.**
>
>
> |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | I support the [NSFW] tag. Some considerations:
* Workplaces have weird rules that we cannot change. A [NSFW] tag lets you know that you probably shouldn't open the link at the office.
* Note that you probably shouldn't browse this site at the office *anyway*; do so at your own risk. I do read it on my lunch break, and I know the risks involved.
* About the children argument: a lot of SF & Fantasy is for adults. This website is meant for adults, and children are not allowed. If you are so concerned that your kids might accidentally read it and be traumatized by the sight of a naked female back, then install an internet filter.
* The image itself is very tame. Like they say, nothing you wouldn't see in a soap commercial.
Let's not turn this into a prudish website, people! | I don't see how work is at all relevant here, unless your work is specifically related to science fiction and fantasy (in which case, it seems likely to me that this image would be considered appropriate).
If my employees were meant to stick to working during their work times (i.e. the traditional viewpoint), then the background image for scifi.se immediately tells me, whatever question they are looking at, that they are goofing off. It doesn't matter what content is in the question and/or answer.
If I'm tolerant of my employees occasionally doing non-work-related things during their work times (i.e. the modern viewpoint), then a screenshot from a PG TV show is perfectly acceptable.
The terms and conditions of the site specify that you must be 13 or older to use it. It seems to me that posters (and editors) and use their own judgement as to whether content is appropriate for a 13-year-old (in particular, 13-year-olds that are likely to be using this site). |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | I'd say that if it's something that *could be* considered offensive, whether adult content, foul language, or blatant flamebait, it should be disallowed. I shouldn't have to worry about my wife or boss seeing offensive stuff on my screen or in server logs. Period.
I fail to see why this is even an issue. If you want to post NSFW stuff, use some other site. This is a *professional, work oriented* site. Not an NSFW site. | I don't see how work is at all relevant here, unless your work is specifically related to science fiction and fantasy (in which case, it seems likely to me that this image would be considered appropriate).
If my employees were meant to stick to working during their work times (i.e. the traditional viewpoint), then the background image for scifi.se immediately tells me, whatever question they are looking at, that they are goofing off. It doesn't matter what content is in the question and/or answer.
If I'm tolerant of my employees occasionally doing non-work-related things during their work times (i.e. the modern viewpoint), then a screenshot from a PG TV show is perfectly acceptable.
The terms and conditions of the site specify that you must be 13 or older to use it. It seems to me that posters (and editors) and use their own judgement as to whether content is appropriate for a 13-year-old (in particular, 13-year-olds that are likely to be using this site). |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | I support the [NSFW] tag. Some considerations:
* Workplaces have weird rules that we cannot change. A [NSFW] tag lets you know that you probably shouldn't open the link at the office.
* Note that you probably shouldn't browse this site at the office *anyway*; do so at your own risk. I do read it on my lunch break, and I know the risks involved.
* About the children argument: a lot of SF & Fantasy is for adults. This website is meant for adults, and children are not allowed. If you are so concerned that your kids might accidentally read it and be traumatized by the sight of a naked female back, then install an internet filter.
* The image itself is very tame. Like they say, nothing you wouldn't see in a soap commercial.
Let's not turn this into a prudish website, people! | I dunno . . . I have always been far more concerned with my children seeing/watching gratuitous violence than I have them seeing sexual activity within reason. The image in question doesn't personally bother me and if my teens saw it, I don't think I'd be particularly fussed. I probably *would* have a problem with my supervisor seeing that at work. It would be considered highly inappropriate, even though we know it's fairly innocuous.
Would a NSFW tag hurt? |
1,582 | [Why did T'Pol act like a human woman with Trip?](https://scifi.stackexchange.com/questions/12370/why-did-tpol-act-like-human-woman-before-sexual-interaction-with-trip)
The topic of the question seems fully within the boundaries of the site, but the actual content is a bit not-quite-family-friendly.
Is this within bounds? I don't think we have any established rules.
[ My personal opinion is that the question is right on the boundary of "decent enough for the site" but very close to stepping over it - any more risque and it'd need to be closed or censored ].
As an alternate solution, we could have a meta-tag "adult-content" to allow filtering out such questions. | 2012/03/02 | [
"https://scifi.meta.stackexchange.com/questions/1582",
"https://scifi.meta.stackexchange.com",
"https://scifi.meta.stackexchange.com/users/976/"
] | The image is from the episode, isn't it?
Is this site's policy actually going to be more limiting than the standards the FCC applies to primetime broadcast television?
A bare female back is hardly "adult content". | I'd say that if it's something that *could be* considered offensive, whether adult content, foul language, or blatant flamebait, it should be disallowed. I shouldn't have to worry about my wife or boss seeing offensive stuff on my screen or in server logs. Period.
I fail to see why this is even an issue. If you want to post NSFW stuff, use some other site. This is a *professional, work oriented* site. Not an NSFW site. |
38,361 | My company's database makes available data to a lot of external applications. So I need to transform the same data to a lot of *dynamic* views. I can see that a former database developer had implemented many long chains of view-function-procedure call sequences to do transformation more common to all external applications. I think, this architecture and so long requests (stored proc calls a function, then function calls some view and this view based on other one and so on) are a performance problem, at least query optimizer does not resolve these issues (please confirm my guesses).
Is it a good approach? Does it cause degradation of performance? If yes, how can I reimplement objects of the database.
At this moment I see these steps to do this:
* analysis of source data structure (own data)
* analysis of all external systems (what formats does database have to provide for)
* separate views, functions, stored procs for every external subsystems (I have to avoid long chains, common to many subsystems DB objects, if it is a cause of problem) | 2011/01/20 | [
"https://softwareengineering.stackexchange.com/questions/38361",
"https://softwareengineering.stackexchange.com",
"https://softwareengineering.stackexchange.com/users/1483/"
] | Have you considered building a [**datamart**](http://en.wikipedia.org/wiki/Data_mart) instead? Maybe it's what your colleague already did?
It highly depends on your specific case, but I understand you can't describe your whole business in your question.
If you are serious about that, I recommend you this great book which not only describe how to do it, but explain deeply all the problems you could encounter in such situations.
[The Data Warehouse Toolkit](http://rads.stackoverflow.com/amzn/click/0471200247)
Check out others [Ralph Kimball books](http://www.amazon.com/Ralph-Kimball/e/B000AP5ULY/ref=ntt_athr_dp_pel_1) as well. | I think the former employee has been trying to create a logical view on the data that is separate from the physical representation.
When clients are attached to Views and/or stored procedures you have some room to refactor the physical representation without the clients requiring any modifications.
Of course this logical layer adds some indirection and may cost extra processing time. However this may still be worthwhile from a maintainability viewpoint though.
Being able to juggle with tables and relationships below this logical layer can also help when dealing with performance issues.
Sometimes being slower is not necessarily a problem, is it still fast enough? |
20,681,579 | **I need to know till what extend we can analyze our Application using Apache Jmeter.**
My script creation is complete. Paramatrized & Correlated. Now I need a deep understanding of Analysis.
Earlier, I just use to focus on Response time, Standard deviation, throughput, etc.
But now my boss wants me to do more analysis. Please help me guys. | 2013/12/19 | [
"https://Stackoverflow.com/questions/20681579",
"https://Stackoverflow.com",
"https://Stackoverflow.com/users/2907700/"
] | You can use these Samplers from JMeter-plugins project:
* <http://jmeter-plugins.org/wiki/DbMon/>
* <http://jmeter-plugins.org/wiki/JMXMon/> | Correctly still divide the tasks and means to solve them. If you need to monitor the parameters of the server utilization - then it needs to use the appropriate means, for example, zabbix. If you need to understand how much resources consumes your server applications - it is necessary to refer to the appropriate monitoring tools, plug-ins, such as Zorka for WebSphere in zabbix. |
22,696 | A company called Devecitech has just created what it calls the 'ENLIL' vertical axis wind turbine, that sits at the side of a highway generating electricity from the wind-power created by passing cars
[](https://i.stack.imgur.com/gK6ms.jpg)
Video here: <http://devecitech.com/>
My question is: does the presence of this turbine 'steal' energy ('negligible' or otherwise) from passing cars by creating drag where there would otherwise be free space?
If so, will it only ever generate less energy than it 'steals' from the passing cars?
Or is it purely harnessing energy that would otherwise be wasted? | 2018/07/12 | [
"https://engineering.stackexchange.com/questions/22696",
"https://engineering.stackexchange.com",
"https://engineering.stackexchange.com/users/16740/"
] | Waterjet cutters work like a charm up to 5mm. I have cut 'fireproof' glass of 4mm and it came out very well. | 1-3 mm is perfectly doable with a cheap-o, off the shelf, carbide glass cutter. So long as your shapes are generally large sweeping curves (i.e. few acute corners), you can use something like [this](https://rads.stackoverflow.com/amzn/click/B078YS9KJY) to score then glass, then something like [this](https://rads.stackoverflow.com/amzn/click/B005I67ZMW) to cleanly snap the piece. |
69,370 | If the covenant of Christ only permits men to call God "Father" (Galatians 4:5, Ephesians 1:5) - How can the prophet Isaiah call YHVH "Father" under Mosaic Law?
**[Yeshayahu יְשַׁעְיָ֣הוּ | Isaiah 63:16]** "For You are our father, for Avraham did not know us, neither did Yisrael recognize us; **You, YHVH, are our Father**; our redeemer of old is your name." (כִּֽי־אַתָּ֣ה אָבִ֔ינוּ כִּ֚י אַבְרָהָם֙ לֹ֣א יְדָעָ֔נוּ וְיִשְׂרָאֵ֖ל לֹ֣א יַכִּירָ֑נוּ אַתָּ֚ה יְהֹוָה֙ אָבִ֔ינוּ גֹּֽאֲלֵ֥נוּ מֵֽעוֹלָ֖ם שְׁמֶֽךָ)
* Yeshayahu יְשַׁעְיָ֣הוּ never knew Jesus of Nazareth, but recognized יְהֹוָה֙ YHVH as Avinu אָבִ֔ינוּ "Our-Father".
**Why was a recognition of Jesus as Christ not required for Israelites like Yeshayahu יְשַׁעְיָ֣הוּ "Isaiah" to call YHVH their Father, under Mosaic Law?** | 2021/09/29 | [
"https://hermeneutics.stackexchange.com/questions/69370",
"https://hermeneutics.stackexchange.com",
"https://hermeneutics.stackexchange.com/users/37964/"
] | You are conflating ‘man’ with ‘nations’….
**EXODUS 4:22** *Then you shall say to Pharaoh, ‘Thus says the Lord: “Israel is My son, My firstborn.*
When Isaiah says … “*For You are our father*”, he is speaking on behalf of the people [nation]. A *prophet* speaks to ‘the people’ on behalf of God *and* to God on behalf of ‘the *people*’.
**GAL 4:6** *And because you are sons* [snip]
Where as in Galatians Paul is saying that *they themselves* [believers] are sons. | Heres some notes.
Verse 16
Thou art our Father. Reference to Pentateuch (Deuteronomy 32:6 ).
Father. A rare word in this connection. Compare Isaiah 64:8 .
Redeemer. See note on Isaiah 60:16 .
Bullingers notes. |
5,849 | What was the actual age of Ayesha (AS) when married to Prophet Muhammad (PBUH)?
EDIT: The too young age (6, 9 etc) is criticized most by Non-Muslims.
According to other sources Ayesha's age was:
* [6 to 9 - Dr Zakir Naik](http://www.youtube.com/watch?v=eT-Rh1auG0A)
* [15 to 16](http://qa.sunnipath.com/issue_view.asp?HD=7&ID=4604&CATE=1)
* [16 to 19 - Javed Ahmed Ghamdi](http://www.al-mawrid.org/pages/questions_english_detail.php?qid=806&cid=170)
* [16 to 19](http://absoluteverdict.blogspot.com/2012/04/hazrat-aishas-real-age-at-marriage-time.html)
* [16 to 20](http://www.islamawareness.net/FAQ/what_was_ayesha.html)
* [18 to 21](http://dawn.com/2012/02/17/of-aishas-age-at-marriage/)
* [18 to 23](http://wn.com/islam_what_was_the_age_of_aisha_ra_when_she_got_married_) | 2012/12/28 | [
"https://islam.stackexchange.com/questions/5849",
"https://islam.stackexchange.com",
"https://islam.stackexchange.com/users/107/"
] | Aishah ( رضي لله عنھا ) was six years old when she married the Prophet (صلى الله عليه وسلم) and nine years old when he consummated the marriage with her. This is what is proven from the books of hadeeth and has been agreed upon by all the scholars of Islam.
Some of the narrations are as follows:
>
> Aishah ( رضي الله عنها ) reported that the Prophet(صلى الله عليه
> وسلم) married her when she was seven years old, and he was taken to
> his house as a bride when she was nine, and her dolls were with her;
> and when he (the Holy Prophet) died she was eighteen years old. ([source](http://sunnah.com/urn/233110))
>
>
> وَحَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ،
> أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ عُرْوَةَ، عَنْ
> عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم تَزَوَّجَهَا وَهْىَ
> بِنْتُ سَبْعِ سِنِينَ وَزُفَّتْ إِلَيْهِ وَهِيَ بِنْتُ تِسْعِ سِنِينَ
> وَلُعَبُهَا مَعَهَا وَمَاتَ عَنْهَا وَهِيَ بِنْتُ ثَمَانَ عَشْرَةَ .
>
>
>
Some narrations state that Aishah’s ( رضي الله عنها ) age was six while others state that it was seven. Imam An-Nawawi ([source](http://islamistruth.files.wordpress.com/2010/09/the-age-of-aishah_s-marriage-between-historians-and-hadith-scholars.pdf)) while commenting on this hadeeth in his Sharh of Saheeh Muslim stated that Ad-Dawoodee said:
>
> "With regards to the narration in which she states that she was
> married at the age of seven while most narrations state that she was
> married at the age of six, then both narrations can be reconciled by
> the fact that she was six years and some months. Therefore in some
> narrations, she only mentioned the number of years of her age at that
> time while in other narrations she meant the year she was about to
> enter, and Allah knows best"
>
>
>
In another narration,
>
> Narrated 'Urwa:
>
>
> The Prophet (sallallahu 'alaihi wa sallam) wrote the (marriage
> contract) with `Aisha while she was six years old and consummated his
> marriage with her while she was nine years old and she remained with
> him for nine years (i.e. till his death). ([source](http://sunnah.com/bukhari/67/93))
>
>
> حَدَّثَنَا قَبِيصَةُ بْنُ عُقْبَةَ، حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامِ
> بْنِ عُرْوَةَ، عَنْ عُرْوَةَ، تَزَوَّجَ النَّبِيُّ صلى الله عليه وسلم
> عَائِشَةَ وَهْىَ ابْنَةُ سِتٍّ وَبَنَى بِهَا وَهْىَ ابْنَةُ تِسْعٍ
> وَمَكَثَتْ عِنْدَهُ تِسْعًا.
>
>
>
There are many similar authentic hadeeth in Sunan Abe Dawood, Sunan An-Nasaaee, Sunan Ibn Majah, Musnad Ahmad ibn Hanbal, Sunan Al-Baihaqi Al-Kubra, Mustadrak Al-Haakim, Al-Mujam Al-Kabeer of At-Tabaraani which proves the above.
I would recommend you to read [this treatise](http://islamistruth.files.wordpress.com/2010/09/the-age-of-aishah_s-marriage-between-historians-and-hadith-scholars.pdf), which clears the doubts, arguments that people pose and misconceptions regarding marriage and age of Aishah ( رضي الله عنها ). | **Conclusion.** She accepted Islam when she was 4 in 1 Besat (بعثت) so that She was about 18 in 2 Hijri.
* As Ebne Molghan (ابن ملقن) (with refer to Bokhari (بخاری)) says: Aisha went to the house of The Prophet(PBUH) in 2 Hijri.
* As Belazari (بلاذري) says: Aisha married with the Prophet (PBUH) in 4 Hijri.
So that we can conclude she was between 18 and 20 on her wedding day.
**Some Details.**
>
> a) Al-Beihaghi, Ibne Asaker, Az-zahabi: Aisha was 10 years younger
> than her sister (Isma Bent Abi Bakr).
>
>
> Ref:
>
>
> 1. Al-Beihaghi (البيهقي، أحمد بن الحسين بن علي بن موسي ابوبكر (متوفاي 458هـ)، سنن البيهقي الكبرى، ج 6 ، ص 204 ، ناشر: مكتبة دار الباز - مكة
> المكرمة، تحقيق: محمد عبد القادر عطا، 1414 - 1994.)
> 2. Ibn Asaker (ابن عساكر الدمشقي الشافعي، أبي القاسم علي بن الحسن إبن هبة الله بن عبد الله،(متوفاي571هـ)، تاريخ مدينة دمشق وذكر فضلها وتسمية
> من حلها من الأماثل، ج 69 ، ص 8 ، تحقيق: محب الدين أبي سعيد عمر بن
> غرامة العمري، ناشر: دار الفكر - بيروت - 1995.)
> 3. Az-zahabi (الذهبي، شمس الدين محمد بن أحمد بن عثمان، (متوفاي748هـ)، سير أعلام النبلاء، ج 2 ، ص 289 ، تحقيق: شعيب الأرناؤوط، محمد نعيم
> العرقسوسي، ناشر: مؤسسة الرسالة - بيروت، الطبعة: التاسعة، 1413هـ..)
>
>
>
and
>
> b) Al-Tabarani, Ibne Asaker, Ibne Asir: Isma (older sister of Aisha)
> was born in 27 before the Hijrat.
>
>
> Ref:
>
>
> 1. Al-Tabarani (الطبراني، سليمان بن أحمد بن أيوب ابوالقاسم (متوفاي360هـ)، المعجم الكبير، ج 24 ، ص 77 ، تحقيق: حمدي بن عبدالمجيد
> السلفي، ناشر: مكتبة الزهراء - الموصل، الطبعة: الثانية، 1404هـ –
> 1983م.)
> 2. Ibne Asaker (ابن عساكر الدمشقي الشافعي، أبي القاسم علي بن الحسن إبن هبة الله بن عبد الله،(متوفاي571هـ)، تاريخ مدينة دمشق وذكر فضلها وتسمية
> من حلها من الأماثل، ج 69 ، ص 9 ، تحقيق: محب الدين أبي سعيد عمر بن
> غرامة العمري، ناشر: دار الفكر - بيروت - 1995.)
> 3. Ibne Asir (الجزري، عز الدين بن الأثير أبي الحسن علي بن محمد (متوفاي630هـ)، أسد الغابة في معرفة الصحابة، ج 7 ، ص 11 ، تحقيق عادل
> أحمد الرفاعي، ناشر: دار إحياء التراث العربي - بيروت / لبنان، الطبعة:
> الأولى، 1417 هـ - 1996 م.)
>
>
>
* **Conclusion 1**: With respect to (a) and (b) you can calculate the year which Aisha was born in. It was 17 before the Hijrat. That is, Ayesha was 4 or 5 at the first year after Bi'that.
>
> c) Al-Bukhari: The Prophet (PBUH) married with Aisha after 3 years
> when Khadija died.
>
>
> Ref:
>
>
> 1. Al-Bukhari (البخاري الجعفي، محمد بن إسماعيل ابوعبدالله (متوفاي256هـ)، صحيح البخاري، ج 3 ، ص 3606، ح3606 ،كتاب فضائل الصحابة،
> بَاب تَزْوِيجِ النبي e خَدِيجَةَ وَفَضْلِهَا رضي الله عنها ، تحقيق د.
> مصطفي ديب البغا، ناشر: دار ابن كثير، اليمامة - بيروت، الطبعة: الثالثة،
> 1407 - 1987.)
>
>
>
and
>
> d) Ibne Molghen: Aisha started living in the Prophet's house in 2
> Hijri.
>
>
> Ref:
>
>
> 1. Ibne Molghen (الأنصاري الشافعي، سراج الدين أبي حفص عمر بن علي بن أحمد المعروف بابن الملقن (متوفاي804 هـ)، غاية السول في خصائص الرسول
> صلى الله عليه وسلم ، ج 1 ، ص 236 ، تحقيق : عبد الله بحر الدين عبد
> الله ، ناشر : دار البشائر الإسلامية - بيروت - 1414هـ - 1993م.)
>
>
>
and
>
> e) Az-zahabi (indirectly): Aisha started living in the Prophet's house
> in 4 Hijri.
>
>
> Ref:
>
>
> 1. Az-zahabi (الذهبي، شمس الدين محمد بن أحمد بن عثمان، (متوفاي748هـ)، تاريخ الإسلام ووفيات المشاهير والأعلام، ج 3 ، ص 288 ، تحقيق د. عمر عبد
> السلام تدمرى، ناشر: دار الكتاب العربي - لبنان/ بيروت، الطبعة: الأولى،
> 1407هـ - 1987م.)
>
>
>
* **Conclusion 2**: With Respect to (Conclusion 1), (c), (d) and (e), by the time Aisha started living with the Prophet (PBUH), she was between 18 and 20. |
5,849 | What was the actual age of Ayesha (AS) when married to Prophet Muhammad (PBUH)?
EDIT: The too young age (6, 9 etc) is criticized most by Non-Muslims.
According to other sources Ayesha's age was:
* [6 to 9 - Dr Zakir Naik](http://www.youtube.com/watch?v=eT-Rh1auG0A)
* [15 to 16](http://qa.sunnipath.com/issue_view.asp?HD=7&ID=4604&CATE=1)
* [16 to 19 - Javed Ahmed Ghamdi](http://www.al-mawrid.org/pages/questions_english_detail.php?qid=806&cid=170)
* [16 to 19](http://absoluteverdict.blogspot.com/2012/04/hazrat-aishas-real-age-at-marriage-time.html)
* [16 to 20](http://www.islamawareness.net/FAQ/what_was_ayesha.html)
* [18 to 21](http://dawn.com/2012/02/17/of-aishas-age-at-marriage/)
* [18 to 23](http://wn.com/islam_what_was_the_age_of_aisha_ra_when_she_got_married_) | 2012/12/28 | [
"https://islam.stackexchange.com/questions/5849",
"https://islam.stackexchange.com",
"https://islam.stackexchange.com/users/107/"
] | Aishah ( رضي لله عنھا ) was six years old when she married the Prophet (صلى الله عليه وسلم) and nine years old when he consummated the marriage with her. This is what is proven from the books of hadeeth and has been agreed upon by all the scholars of Islam.
Some of the narrations are as follows:
>
> Aishah ( رضي الله عنها ) reported that the Prophet(صلى الله عليه
> وسلم) married her when she was seven years old, and he was taken to
> his house as a bride when she was nine, and her dolls were with her;
> and when he (the Holy Prophet) died she was eighteen years old. ([source](http://sunnah.com/urn/233110))
>
>
> وَحَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ،
> أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ عُرْوَةَ، عَنْ
> عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم تَزَوَّجَهَا وَهْىَ
> بِنْتُ سَبْعِ سِنِينَ وَزُفَّتْ إِلَيْهِ وَهِيَ بِنْتُ تِسْعِ سِنِينَ
> وَلُعَبُهَا مَعَهَا وَمَاتَ عَنْهَا وَهِيَ بِنْتُ ثَمَانَ عَشْرَةَ .
>
>
>
Some narrations state that Aishah’s ( رضي الله عنها ) age was six while others state that it was seven. Imam An-Nawawi ([source](http://islamistruth.files.wordpress.com/2010/09/the-age-of-aishah_s-marriage-between-historians-and-hadith-scholars.pdf)) while commenting on this hadeeth in his Sharh of Saheeh Muslim stated that Ad-Dawoodee said:
>
> "With regards to the narration in which she states that she was
> married at the age of seven while most narrations state that she was
> married at the age of six, then both narrations can be reconciled by
> the fact that she was six years and some months. Therefore in some
> narrations, she only mentioned the number of years of her age at that
> time while in other narrations she meant the year she was about to
> enter, and Allah knows best"
>
>
>
In another narration,
>
> Narrated 'Urwa:
>
>
> The Prophet (sallallahu 'alaihi wa sallam) wrote the (marriage
> contract) with `Aisha while she was six years old and consummated his
> marriage with her while she was nine years old and she remained with
> him for nine years (i.e. till his death). ([source](http://sunnah.com/bukhari/67/93))
>
>
> حَدَّثَنَا قَبِيصَةُ بْنُ عُقْبَةَ، حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامِ
> بْنِ عُرْوَةَ، عَنْ عُرْوَةَ، تَزَوَّجَ النَّبِيُّ صلى الله عليه وسلم
> عَائِشَةَ وَهْىَ ابْنَةُ سِتٍّ وَبَنَى بِهَا وَهْىَ ابْنَةُ تِسْعٍ
> وَمَكَثَتْ عِنْدَهُ تِسْعًا.
>
>
>
There are many similar authentic hadeeth in Sunan Abe Dawood, Sunan An-Nasaaee, Sunan Ibn Majah, Musnad Ahmad ibn Hanbal, Sunan Al-Baihaqi Al-Kubra, Mustadrak Al-Haakim, Al-Mujam Al-Kabeer of At-Tabaraani which proves the above.
I would recommend you to read [this treatise](http://islamistruth.files.wordpress.com/2010/09/the-age-of-aishah_s-marriage-between-historians-and-hadith-scholars.pdf), which clears the doubts, arguments that people pose and misconceptions regarding marriage and age of Aishah ( رضي الله عنها ). | Kindly Read Source: <https://www.dawn.com/news/696084/of-aishas-age-at-marriage>
First point:
>
> There is only one hadith by Hisham which suggests the age of Hazrat Aisha as being nine when she came to live with her husband......His life is divided into two periods: in 131A.H. the Madani period ended, and the Iraqi period started, when Hisham was 71 years old. Hafiz Zehbi has spoken about Hisham’s loss of memory in his later period.........All the narrators of this hadith are Iraqis who had heard it from Hisham. **Allama Kandhulvi says that the words spoken in connection with Hazrat Aisha’s age were tissa ashara, meaning 19, when Hisham only heard (or remembered), tissa, meaning nine.** Maulana Usmani thinks this change was purposely and maliciously made later.
>
>
>
Second Point writer has:
>
> Historian Ibn Ishaq in his Sirat Rasul Allah has given a list of the people who accepted Islam in the first year of the proclamation of Islam, in which **Hazrat Aisha’s name is mentioned as Abu Bakr’s “little daughter Aisha”.** If we accept Hisham’s calculations, she was not even born at that time.
>
>
>
Third Point:
>
> Some time after the death of the Prophet’s first wife, Hazrat Khadija, Khawla suggested to the Prophet that he get married again, to a bikrun, referring to Hazrat Aisha (Musnad Ahmed). **In Arabic bikrun is used for an unmarried girl who has crossed the age of puberty and is of marriageable age. The word cannot be used for a six-year-old girl.**
>
>
>
Fourth One:
>
> **There is consensus that Hazrat Aisha was 10 years younger than her elder sister Asma, whose age at the time of the hijrah, or migration to Madina, was about 28. It can be concluded that Hazrat Aisha was about 18 years old at migration.** On her moving to the Prophet’s house, she was a young woman at 21.
>
>
> |
5,849 | What was the actual age of Ayesha (AS) when married to Prophet Muhammad (PBUH)?
EDIT: The too young age (6, 9 etc) is criticized most by Non-Muslims.
According to other sources Ayesha's age was:
* [6 to 9 - Dr Zakir Naik](http://www.youtube.com/watch?v=eT-Rh1auG0A)
* [15 to 16](http://qa.sunnipath.com/issue_view.asp?HD=7&ID=4604&CATE=1)
* [16 to 19 - Javed Ahmed Ghamdi](http://www.al-mawrid.org/pages/questions_english_detail.php?qid=806&cid=170)
* [16 to 19](http://absoluteverdict.blogspot.com/2012/04/hazrat-aishas-real-age-at-marriage-time.html)
* [16 to 20](http://www.islamawareness.net/FAQ/what_was_ayesha.html)
* [18 to 21](http://dawn.com/2012/02/17/of-aishas-age-at-marriage/)
* [18 to 23](http://wn.com/islam_what_was_the_age_of_aisha_ra_when_she_got_married_) | 2012/12/28 | [
"https://islam.stackexchange.com/questions/5849",
"https://islam.stackexchange.com",
"https://islam.stackexchange.com/users/107/"
] | Aishah ( رضي لله عنھا ) was six years old when she married the Prophet (صلى الله عليه وسلم) and nine years old when he consummated the marriage with her. This is what is proven from the books of hadeeth and has been agreed upon by all the scholars of Islam.
Some of the narrations are as follows:
>
> Aishah ( رضي الله عنها ) reported that the Prophet(صلى الله عليه
> وسلم) married her when she was seven years old, and he was taken to
> his house as a bride when she was nine, and her dolls were with her;
> and when he (the Holy Prophet) died she was eighteen years old. ([source](http://sunnah.com/urn/233110))
>
>
> وَحَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ،
> أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ عُرْوَةَ، عَنْ
> عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم تَزَوَّجَهَا وَهْىَ
> بِنْتُ سَبْعِ سِنِينَ وَزُفَّتْ إِلَيْهِ وَهِيَ بِنْتُ تِسْعِ سِنِينَ
> وَلُعَبُهَا مَعَهَا وَمَاتَ عَنْهَا وَهِيَ بِنْتُ ثَمَانَ عَشْرَةَ .
>
>
>
Some narrations state that Aishah’s ( رضي الله عنها ) age was six while others state that it was seven. Imam An-Nawawi ([source](http://islamistruth.files.wordpress.com/2010/09/the-age-of-aishah_s-marriage-between-historians-and-hadith-scholars.pdf)) while commenting on this hadeeth in his Sharh of Saheeh Muslim stated that Ad-Dawoodee said:
>
> "With regards to the narration in which she states that she was
> married at the age of seven while most narrations state that she was
> married at the age of six, then both narrations can be reconciled by
> the fact that she was six years and some months. Therefore in some
> narrations, she only mentioned the number of years of her age at that
> time while in other narrations she meant the year she was about to
> enter, and Allah knows best"
>
>
>
In another narration,
>
> Narrated 'Urwa:
>
>
> The Prophet (sallallahu 'alaihi wa sallam) wrote the (marriage
> contract) with `Aisha while she was six years old and consummated his
> marriage with her while she was nine years old and she remained with
> him for nine years (i.e. till his death). ([source](http://sunnah.com/bukhari/67/93))
>
>
> حَدَّثَنَا قَبِيصَةُ بْنُ عُقْبَةَ، حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامِ
> بْنِ عُرْوَةَ، عَنْ عُرْوَةَ، تَزَوَّجَ النَّبِيُّ صلى الله عليه وسلم
> عَائِشَةَ وَهْىَ ابْنَةُ سِتٍّ وَبَنَى بِهَا وَهْىَ ابْنَةُ تِسْعٍ
> وَمَكَثَتْ عِنْدَهُ تِسْعًا.
>
>
>
There are many similar authentic hadeeth in Sunan Abe Dawood, Sunan An-Nasaaee, Sunan Ibn Majah, Musnad Ahmad ibn Hanbal, Sunan Al-Baihaqi Al-Kubra, Mustadrak Al-Haakim, Al-Mujam Al-Kabeer of At-Tabaraani which proves the above.
I would recommend you to read [this treatise](http://islamistruth.files.wordpress.com/2010/09/the-age-of-aishah_s-marriage-between-historians-and-hadith-scholars.pdf), which clears the doubts, arguments that people pose and misconceptions regarding marriage and age of Aishah ( رضي الله عنها ). | Classical Sunni scholars argue A'isha (ra), daughter of Abu Bakr (ra), married the Prophet (saw) at the age of six, but he consummated the marriage when she reached puberty at the age of nine.This by no means suggests she was a child, rather that is determined by the social and biological facts of the time, which suggest she was a young adult capable of dealing with the responsibility of marriage. This is what Islamic sources say about her age when she married the Rasool (saw) <https://www.islamiqate.com/3197/what-islamic-sources-say-about-the-age-aisha-the-time-marriage>. |
365,988 | As per my last question, this has less to do with cold, hard, and fast calculations and more to do with the interplay between mathematics and philosophy...but as armchair philosophers aren't as hard to come by as knowledgeable mathematicians, I'm asking this here.
Schrodinger's thought experiment about the cat came to the conclusion that the cat in the box was both alive and dead at the same time until it was actually observed, and that it was the observation of the cat that made reality collapse into only one of those outcomes (either the cat is alive, or the cat is dead, but not both.)
What I take away from that is that simply our observations can have cause/effect relationships to phenomena at the quantum level. Whether my understanding of this concept is a little too simplistic or not, I'll leave up to the opinions of those who are more knowledgeable in this matter than I.
At any rate, if such is the case, then what I'm pondering is this:
Let's assume that accurate mathematical models can be made of the inner workings of subatomic particles and their interactions. If simply by observing those particles we can change how they act, would that not mean that observation itself affects certain areas of mathematics? That certain relationships and concepts in math change based on our observance of them?
And again, just like my last question, I'm not looking for reinforcement here; I know my conclusions have to be incorrect, and I'd be interested to find out why from a mathematical point of view that's more finely honed than my own. Thanks!
---
Ah, I get what you guys are saying. Mathematics exists as a descriptor of objects/ideas/concepts, and nothing else...even when what it is describing is itself.
So while observation would affect objects, and perhaps to some extent ideas, observation would do absolutely nothing to the actual description of those objects and ideas, which is why mathematics wouldn't be affected.
I knew was going wrong somewhere - thanks for drawing it out, friends! | 2013/04/19 | [
"https://math.stackexchange.com/questions/365988",
"https://math.stackexchange.com",
"https://math.stackexchange.com/users/73167/"
] | Suppose you look at a cow and say "That cow is eating grass.' But the cow hears you, and looks up startled! It's now not eating grass.
Does any of this change what you mean by "eating grass"? | Even if you assume we have accurate mathematical models to describe the physics of particle interactions, remember that mathematics is merely serving as a language to "model" these systems. Moreover, the act of observation should be worked into the model, as observation is a physical process (usually observing something requires shooting photons at it). In particular, the mathematical formalism of quantum mechanics basically works observers into the picture via self-adjoint operators on the Hilbert space of states of the system you are considering. On the other hand I don't know what it means to "observe mathematics", or how mathematics could be affected by observation. Remember that physics always requires making some sort of real-world measurement, while mathematics never requires making any such measurements. |
210,328 | Using Cycles, for a cartoony animation character I need spikes to be seen only from the character's edges and behind the character but never seen in facing angles. I want to avoid having to render the scene twice to be composited after.
For example: 2 meshes,
1 skin color, smooth, rigged,
1 blue spiky mesh sticking out, rigged, never seen in front.
I have no idea how to accomplish this.
Do I have to account for camera angle and normals of the spike's base?
Can I just layer one over the other with nodes?
Default look:
[](https://i.stack.imgur.com/WaOYF.jpg)
Approximate Desired result done in Photoshop.
[](https://i.stack.imgur.com/T2tkT.jpg)
[](https://blend-exchange.giantcowfilms.com/b/Nv2ZKWeR/) | 2021/02/02 | [
"https://blender.stackexchange.com/questions/210328",
"https://blender.stackexchange.com",
"https://blender.stackexchange.com/users/20109/"
] | This seems like a task for the compositor, but you explicitly stated that you don't want to render multiple times. That means only AOVs remain an option for compositing. After trying it I discarded the idea, because it will cause artifacts. Instead I found a solution using only the shader and some Custom Normals.
First you need to redo the spikes. You need a spike geometry with Custom Normals pointing along the spike direction. You can do that in Editmode of the spike by using *Mesh > Normals > Point to Target* or using `Alt`+`L`. Then you can use instancing to put the spikes at the vertices of your model. Then you need to disable ray visibility for any other ray than a camera ray in the object settings of your spikes.
After this setup you can make this shader:
[](https://i.stack.imgur.com/Jbubi.png)
The result looks like this:
[](https://i.stack.imgur.com/dDA9y.png)
You are also free to change your material in any way you want, which could have been difficult with the compositor approach.
Here is the Blend File:
[](https://blend-exchange.giantcowfilms.com/b/XsWM5W8E/) | The closest I got was using cones with **inverted normals** and backface culling enabled:
[](https://i.stack.imgur.com/791ZH.png)
But as you can see, cones pointing slightly towards the camera still get shown. |
383,195 | SUMMARY:
Here is what works:
*Raspberry Pi (I²C) <-> 1 m cable <-> sensor (I²C)*
Here is what I'm trying to do (doesn't work, hence question):
*Raspberry Pi (I²C) <-> 30 m cable <-> sensor (I²C)*
The "equation" to solve is thus:
*Raspberry Pi (I²C, SPI, and other) <-> X <-> 30 m cable <-> Y <-> sensor (I²C/SPI)*
Solve for X and Y
DETAIL:
I'm working with a bunch of sensors configured in a star network/topology.
[](https://i.stack.imgur.com/71MsR.png)
A Raspberry Pi Zero is used as a central "hub", where all the sensor data is collected and processed. All the sensors are the same and use an I²C protocol (they also offer an SPI bus interface). That being said, I currently have an I²C multiplexer connected to the Raspberry Pi Zero to enable multiple devices configured with the same I²C hardware address. All sensors are wired to the Raspberry Pi Zero, using 26/4 shielded cable. Everything currently works as intended.
Having the proof of concept in place, I now want to extend the reach of the star network/topology by 20-30 m on each sensor-hub connection. I thought I could just use longer wire, but apparently the I²C protocol limits the length of wire extension. I've read [various tricks/solutions](https://forum.arduino.cc/index.php?topic=57604.0) on how to extend the length, such as lowering the frequency, changing resistors, etc.
I'll be honest; I'm not an electrical engineer, so some of that stuff seems a bit more advanced, and I don't really have the knowledge or tools to assess the effectiveness of those types of altercations.
Anyway, I've done some digging, and I've found various chips I can potentially implement as more of a "plug and play" solution. That being said, much of the material I read was from years ago, and I don't know if those solutions are still viable. Here are the chips I've found
* P82B96, which apparently has a successor: PCA9600?
* P82B715
Comparing the two, I've read the first item is more versatile. I've also read the second item is older and [requires a lot of power](https://www.hackster.io/chipmc/extend-the-reach-of-your-i2c-sensor-simply-and-inexpensively-ea6b53), making remote deployments (battery powered) less practical. I recently came across another solution, where you use an [I²C to 1-wire converter](https://www.maximintegrated.com/en/products/interface/controllers-expanders/DS28E17.html) since the 1-wire protocol isn't as sensitive to increases in wire length
* DS28E17 (and potentially add DS2484 at hub)
This seems like a potential solution, but I haven't heard much about it being used by others. The only source of information I got was from the company webpage and videos. If I read the datasheet correctly, the solution doesn't require much power either. I'm wondering if others are buying what they're selling and if it works?
Anyway, again, I'm not an electrical engineer, so I could really use some advice. It seems like the I²C protocol is what a lot of sensors are using (at least the DIY embedded market), so [I imagine I'm not the only one facing the issue of extending the I²C communication](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/).
Here are my solution requirements:
* extend each sensor out from the central hub 20-30 m
* must be wired connection
* low power consumption (I'm running the network on battery power)
EDIT:
I've done some more digging over the weekend and I've come across [this chip set](https://www.mouser.com/Microchip/Semiconductors/Interface-ICs/CAN-Interface-IC/MCP2542-Series/Newest-Products/_/N-45lu7?P=1y9ix0wZ1z0zl2w&gclid=EAIaIQobChMI5NzAw7yO3AIVgcpkCh0caArzEAAYASAAEgIScvD_BwE) (MCP25\*), which sounds like a CAN-to-SPI interface. THIS WON'T WORK...SEE @Maple's comments below. I'm certainly not saying that's the only chip set offering this conversion, it's just the first one I came across. The sensors that I'm using do have a SPI bus interface, so I think I might be able to directly connect one of these chips to each sensor? I only have 5 sensor nodes connected to the Raspberry Pi in my star topology, so I believe I'm well within the constraints on the number of nodes the CAN bus can support. The question would be then how to configure the rest of the bus. Would I simply connect one end of a Cat 5 cable to one of the CAN-to-SPI chips? The wire would then run 20-30 m to the Raspberry Pi. Could I then add one more chip at the Raspberry Pi to "invert" the conversion an communicate with the Raspberry Pi? Would there be a way to connect all five nodes to the same interface/chip? I don't think the Raspberry Pi has a native CAN bus support, but obviously does have SPI (I think you can only connect two devices?). If those chips could be added on the sensor nodes, what would be needed to interface the Raspberry Pi?
EDIT\_2:
After gathering further knowledge from everyone's feedback (thanks), I decided to keep digging. To no surprise, I came across yet another potential solution! I was reading through the comments on one of the [links I pointed to above](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/), and someone mentioned a [PCA9615 chip](https://www.nxp.com/docs/en/data-sheet/PCA9615.pdf). A quick Google search on this chip introduces "differential I²C". From a layman point of view, this sounds like a solution which wouldn't require me to change my software. Aside from that, I don't fully know the pros/cons or if it meets my three requirements listed. I will read further into the datasheet, but if anyone has feedback on this solution, I'm all ears! | 2018/07/05 | [
"https://electronics.stackexchange.com/questions/383195",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/125775/"
] | This NXP note outlines methods to get I2C bus system to over 300 m long at 60 kbits/s, [AN11084](https://www.nxp.com/docs/en/application-note/AN11084.pdf). The solutions include twisted lines, PCA9605 repeaters, and delay-generating logic at each slave. Good luck. | I also argue to look at [this](https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling). <https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling>
It is immune to common mode noise, independent of ground connection and also runs for a few 10s of meters easily still providing high bit rate compared to I2C standard.
If you can provide the schematics it block diagram of intended connection, a better scheme can be worked out to lower power consumption further.
M LVDS (multi LVDS) can be the right candidate. You can use individual channels for I2C clock and data.
Data line is bidirectional but possible to handle via arbitration. |
383,195 | SUMMARY:
Here is what works:
*Raspberry Pi (I²C) <-> 1 m cable <-> sensor (I²C)*
Here is what I'm trying to do (doesn't work, hence question):
*Raspberry Pi (I²C) <-> 30 m cable <-> sensor (I²C)*
The "equation" to solve is thus:
*Raspberry Pi (I²C, SPI, and other) <-> X <-> 30 m cable <-> Y <-> sensor (I²C/SPI)*
Solve for X and Y
DETAIL:
I'm working with a bunch of sensors configured in a star network/topology.
[](https://i.stack.imgur.com/71MsR.png)
A Raspberry Pi Zero is used as a central "hub", where all the sensor data is collected and processed. All the sensors are the same and use an I²C protocol (they also offer an SPI bus interface). That being said, I currently have an I²C multiplexer connected to the Raspberry Pi Zero to enable multiple devices configured with the same I²C hardware address. All sensors are wired to the Raspberry Pi Zero, using 26/4 shielded cable. Everything currently works as intended.
Having the proof of concept in place, I now want to extend the reach of the star network/topology by 20-30 m on each sensor-hub connection. I thought I could just use longer wire, but apparently the I²C protocol limits the length of wire extension. I've read [various tricks/solutions](https://forum.arduino.cc/index.php?topic=57604.0) on how to extend the length, such as lowering the frequency, changing resistors, etc.
I'll be honest; I'm not an electrical engineer, so some of that stuff seems a bit more advanced, and I don't really have the knowledge or tools to assess the effectiveness of those types of altercations.
Anyway, I've done some digging, and I've found various chips I can potentially implement as more of a "plug and play" solution. That being said, much of the material I read was from years ago, and I don't know if those solutions are still viable. Here are the chips I've found
* P82B96, which apparently has a successor: PCA9600?
* P82B715
Comparing the two, I've read the first item is more versatile. I've also read the second item is older and [requires a lot of power](https://www.hackster.io/chipmc/extend-the-reach-of-your-i2c-sensor-simply-and-inexpensively-ea6b53), making remote deployments (battery powered) less practical. I recently came across another solution, where you use an [I²C to 1-wire converter](https://www.maximintegrated.com/en/products/interface/controllers-expanders/DS28E17.html) since the 1-wire protocol isn't as sensitive to increases in wire length
* DS28E17 (and potentially add DS2484 at hub)
This seems like a potential solution, but I haven't heard much about it being used by others. The only source of information I got was from the company webpage and videos. If I read the datasheet correctly, the solution doesn't require much power either. I'm wondering if others are buying what they're selling and if it works?
Anyway, again, I'm not an electrical engineer, so I could really use some advice. It seems like the I²C protocol is what a lot of sensors are using (at least the DIY embedded market), so [I imagine I'm not the only one facing the issue of extending the I²C communication](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/).
Here are my solution requirements:
* extend each sensor out from the central hub 20-30 m
* must be wired connection
* low power consumption (I'm running the network on battery power)
EDIT:
I've done some more digging over the weekend and I've come across [this chip set](https://www.mouser.com/Microchip/Semiconductors/Interface-ICs/CAN-Interface-IC/MCP2542-Series/Newest-Products/_/N-45lu7?P=1y9ix0wZ1z0zl2w&gclid=EAIaIQobChMI5NzAw7yO3AIVgcpkCh0caArzEAAYASAAEgIScvD_BwE) (MCP25\*), which sounds like a CAN-to-SPI interface. THIS WON'T WORK...SEE @Maple's comments below. I'm certainly not saying that's the only chip set offering this conversion, it's just the first one I came across. The sensors that I'm using do have a SPI bus interface, so I think I might be able to directly connect one of these chips to each sensor? I only have 5 sensor nodes connected to the Raspberry Pi in my star topology, so I believe I'm well within the constraints on the number of nodes the CAN bus can support. The question would be then how to configure the rest of the bus. Would I simply connect one end of a Cat 5 cable to one of the CAN-to-SPI chips? The wire would then run 20-30 m to the Raspberry Pi. Could I then add one more chip at the Raspberry Pi to "invert" the conversion an communicate with the Raspberry Pi? Would there be a way to connect all five nodes to the same interface/chip? I don't think the Raspberry Pi has a native CAN bus support, but obviously does have SPI (I think you can only connect two devices?). If those chips could be added on the sensor nodes, what would be needed to interface the Raspberry Pi?
EDIT\_2:
After gathering further knowledge from everyone's feedback (thanks), I decided to keep digging. To no surprise, I came across yet another potential solution! I was reading through the comments on one of the [links I pointed to above](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/), and someone mentioned a [PCA9615 chip](https://www.nxp.com/docs/en/data-sheet/PCA9615.pdf). A quick Google search on this chip introduces "differential I²C". From a layman point of view, this sounds like a solution which wouldn't require me to change my software. Aside from that, I don't fully know the pros/cons or if it meets my three requirements listed. I will read further into the datasheet, but if anyone has feedback on this solution, I'm all ears! | 2018/07/05 | [
"https://electronics.stackexchange.com/questions/383195",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/125775/"
] | I suspect there are other kinds of I2C extenders but I am only familiar with two - buffers (like PCA9605, P82B715) and splitters (like PCA9600, P82B96). They all designed to isolate higher bus capacitance of the long runs by increasing sinking capability of the outputs. It seems the buffers all approaching EOL now.
Note, however, that increasing sinking capability basically means increasing currents, which does not bode well with your requirement of low power consumption.
There are many application notes that I'd recommend reading, like already suggested by @ali-chen [AN11084](https://www.nxp.com/docs/en/application-note/AN11084.pdf) or [AN11075](https://www.nxp.com/docs/en/application-note/AN11075.pdf), [AN10658](https://www.nxp.com/docs/en/application-note/AN10658.pdf). Interesting though, that even those of them that use twisted pairs in their topology still rely on single-ended signalling. I am pretty sure that whatever application note or device you would choose should work well.
What I would like to suggest though, is taking a look at [this device](https://sandboxelectronics.com/?product=pca9600-differential-i2c-long-cable-extender-with-buck-convertor-and-rj45-adaptor) first. They describe it as "PCA9600 extender". However buried deep inside the technical description you can find clever use of CAN transceiver chip [PCA82C251](https://www.nxp.com/docs/en/data-sheet/PCA82C251.pdf) to transform I2C signals (split to Tx, Rx by PCA9600) into differential signals.
The above already has an advantage of high noise immunity without any shielding. And it can give you high speed communication over 100 m distances. But here is another trick for you - CAN bus can operate at 3.3V with same speed and reliability as at 5V, while at the same time reducing power consumption by more than 50%. I think this justifies a closer look for your application. | This NXP note outlines methods to get I2C bus system to over 300 m long at 60 kbits/s, [AN11084](https://www.nxp.com/docs/en/application-note/AN11084.pdf). The solutions include twisted lines, PCA9605 repeaters, and delay-generating logic at each slave. Good luck. |
383,195 | SUMMARY:
Here is what works:
*Raspberry Pi (I²C) <-> 1 m cable <-> sensor (I²C)*
Here is what I'm trying to do (doesn't work, hence question):
*Raspberry Pi (I²C) <-> 30 m cable <-> sensor (I²C)*
The "equation" to solve is thus:
*Raspberry Pi (I²C, SPI, and other) <-> X <-> 30 m cable <-> Y <-> sensor (I²C/SPI)*
Solve for X and Y
DETAIL:
I'm working with a bunch of sensors configured in a star network/topology.
[](https://i.stack.imgur.com/71MsR.png)
A Raspberry Pi Zero is used as a central "hub", where all the sensor data is collected and processed. All the sensors are the same and use an I²C protocol (they also offer an SPI bus interface). That being said, I currently have an I²C multiplexer connected to the Raspberry Pi Zero to enable multiple devices configured with the same I²C hardware address. All sensors are wired to the Raspberry Pi Zero, using 26/4 shielded cable. Everything currently works as intended.
Having the proof of concept in place, I now want to extend the reach of the star network/topology by 20-30 m on each sensor-hub connection. I thought I could just use longer wire, but apparently the I²C protocol limits the length of wire extension. I've read [various tricks/solutions](https://forum.arduino.cc/index.php?topic=57604.0) on how to extend the length, such as lowering the frequency, changing resistors, etc.
I'll be honest; I'm not an electrical engineer, so some of that stuff seems a bit more advanced, and I don't really have the knowledge or tools to assess the effectiveness of those types of altercations.
Anyway, I've done some digging, and I've found various chips I can potentially implement as more of a "plug and play" solution. That being said, much of the material I read was from years ago, and I don't know if those solutions are still viable. Here are the chips I've found
* P82B96, which apparently has a successor: PCA9600?
* P82B715
Comparing the two, I've read the first item is more versatile. I've also read the second item is older and [requires a lot of power](https://www.hackster.io/chipmc/extend-the-reach-of-your-i2c-sensor-simply-and-inexpensively-ea6b53), making remote deployments (battery powered) less practical. I recently came across another solution, where you use an [I²C to 1-wire converter](https://www.maximintegrated.com/en/products/interface/controllers-expanders/DS28E17.html) since the 1-wire protocol isn't as sensitive to increases in wire length
* DS28E17 (and potentially add DS2484 at hub)
This seems like a potential solution, but I haven't heard much about it being used by others. The only source of information I got was from the company webpage and videos. If I read the datasheet correctly, the solution doesn't require much power either. I'm wondering if others are buying what they're selling and if it works?
Anyway, again, I'm not an electrical engineer, so I could really use some advice. It seems like the I²C protocol is what a lot of sensors are using (at least the DIY embedded market), so [I imagine I'm not the only one facing the issue of extending the I²C communication](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/).
Here are my solution requirements:
* extend each sensor out from the central hub 20-30 m
* must be wired connection
* low power consumption (I'm running the network on battery power)
EDIT:
I've done some more digging over the weekend and I've come across [this chip set](https://www.mouser.com/Microchip/Semiconductors/Interface-ICs/CAN-Interface-IC/MCP2542-Series/Newest-Products/_/N-45lu7?P=1y9ix0wZ1z0zl2w&gclid=EAIaIQobChMI5NzAw7yO3AIVgcpkCh0caArzEAAYASAAEgIScvD_BwE) (MCP25\*), which sounds like a CAN-to-SPI interface. THIS WON'T WORK...SEE @Maple's comments below. I'm certainly not saying that's the only chip set offering this conversion, it's just the first one I came across. The sensors that I'm using do have a SPI bus interface, so I think I might be able to directly connect one of these chips to each sensor? I only have 5 sensor nodes connected to the Raspberry Pi in my star topology, so I believe I'm well within the constraints on the number of nodes the CAN bus can support. The question would be then how to configure the rest of the bus. Would I simply connect one end of a Cat 5 cable to one of the CAN-to-SPI chips? The wire would then run 20-30 m to the Raspberry Pi. Could I then add one more chip at the Raspberry Pi to "invert" the conversion an communicate with the Raspberry Pi? Would there be a way to connect all five nodes to the same interface/chip? I don't think the Raspberry Pi has a native CAN bus support, but obviously does have SPI (I think you can only connect two devices?). If those chips could be added on the sensor nodes, what would be needed to interface the Raspberry Pi?
EDIT\_2:
After gathering further knowledge from everyone's feedback (thanks), I decided to keep digging. To no surprise, I came across yet another potential solution! I was reading through the comments on one of the [links I pointed to above](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/), and someone mentioned a [PCA9615 chip](https://www.nxp.com/docs/en/data-sheet/PCA9615.pdf). A quick Google search on this chip introduces "differential I²C". From a layman point of view, this sounds like a solution which wouldn't require me to change my software. Aside from that, I don't fully know the pros/cons or if it meets my three requirements listed. I will read further into the datasheet, but if anyone has feedback on this solution, I'm all ears! | 2018/07/05 | [
"https://electronics.stackexchange.com/questions/383195",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/125775/"
] | The Onewire solution with the DS28E17 is the one which works mostly out of the box. You may even use the bitbanging host (e.g. on GPIO4) and get away with almost no extra hardware. Each DS28E17 on the bus is automatically appearing as an I²C host adapter, no software changes needed. Drawbacks:
* The Onewire has to be a bus, not a star. If you had a star layout, use lobes to make it a physical bus. Or use several Onewire buses, the DS2482-800 offers eight.
* It's low-speed, just about 15kBaud with a lot of overhead. You cannot use it for high-throughput sensors.
Forget about the *DS2484 behind a DS28E17* idea. That simply squares the overhead so much sending a few bytes takes a second or so. (DS28E17 behind a DS2484 or DS2482-800 in contrary is the intended use and avoids bitbanging.)
The reason that chip isn't much used by other people yet is it came out just in 2016 and the Linux driver is available just since kernel 4.15.
(And a caution: The DS28E17 is a 3.3V only device.) | This NXP note outlines methods to get I2C bus system to over 300 m long at 60 kbits/s, [AN11084](https://www.nxp.com/docs/en/application-note/AN11084.pdf). The solutions include twisted lines, PCA9605 repeaters, and delay-generating logic at each slave. Good luck. |
383,195 | SUMMARY:
Here is what works:
*Raspberry Pi (I²C) <-> 1 m cable <-> sensor (I²C)*
Here is what I'm trying to do (doesn't work, hence question):
*Raspberry Pi (I²C) <-> 30 m cable <-> sensor (I²C)*
The "equation" to solve is thus:
*Raspberry Pi (I²C, SPI, and other) <-> X <-> 30 m cable <-> Y <-> sensor (I²C/SPI)*
Solve for X and Y
DETAIL:
I'm working with a bunch of sensors configured in a star network/topology.
[](https://i.stack.imgur.com/71MsR.png)
A Raspberry Pi Zero is used as a central "hub", where all the sensor data is collected and processed. All the sensors are the same and use an I²C protocol (they also offer an SPI bus interface). That being said, I currently have an I²C multiplexer connected to the Raspberry Pi Zero to enable multiple devices configured with the same I²C hardware address. All sensors are wired to the Raspberry Pi Zero, using 26/4 shielded cable. Everything currently works as intended.
Having the proof of concept in place, I now want to extend the reach of the star network/topology by 20-30 m on each sensor-hub connection. I thought I could just use longer wire, but apparently the I²C protocol limits the length of wire extension. I've read [various tricks/solutions](https://forum.arduino.cc/index.php?topic=57604.0) on how to extend the length, such as lowering the frequency, changing resistors, etc.
I'll be honest; I'm not an electrical engineer, so some of that stuff seems a bit more advanced, and I don't really have the knowledge or tools to assess the effectiveness of those types of altercations.
Anyway, I've done some digging, and I've found various chips I can potentially implement as more of a "plug and play" solution. That being said, much of the material I read was from years ago, and I don't know if those solutions are still viable. Here are the chips I've found
* P82B96, which apparently has a successor: PCA9600?
* P82B715
Comparing the two, I've read the first item is more versatile. I've also read the second item is older and [requires a lot of power](https://www.hackster.io/chipmc/extend-the-reach-of-your-i2c-sensor-simply-and-inexpensively-ea6b53), making remote deployments (battery powered) less practical. I recently came across another solution, where you use an [I²C to 1-wire converter](https://www.maximintegrated.com/en/products/interface/controllers-expanders/DS28E17.html) since the 1-wire protocol isn't as sensitive to increases in wire length
* DS28E17 (and potentially add DS2484 at hub)
This seems like a potential solution, but I haven't heard much about it being used by others. The only source of information I got was from the company webpage and videos. If I read the datasheet correctly, the solution doesn't require much power either. I'm wondering if others are buying what they're selling and if it works?
Anyway, again, I'm not an electrical engineer, so I could really use some advice. It seems like the I²C protocol is what a lot of sensors are using (at least the DIY embedded market), so [I imagine I'm not the only one facing the issue of extending the I²C communication](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/).
Here are my solution requirements:
* extend each sensor out from the central hub 20-30 m
* must be wired connection
* low power consumption (I'm running the network on battery power)
EDIT:
I've done some more digging over the weekend and I've come across [this chip set](https://www.mouser.com/Microchip/Semiconductors/Interface-ICs/CAN-Interface-IC/MCP2542-Series/Newest-Products/_/N-45lu7?P=1y9ix0wZ1z0zl2w&gclid=EAIaIQobChMI5NzAw7yO3AIVgcpkCh0caArzEAAYASAAEgIScvD_BwE) (MCP25\*), which sounds like a CAN-to-SPI interface. THIS WON'T WORK...SEE @Maple's comments below. I'm certainly not saying that's the only chip set offering this conversion, it's just the first one I came across. The sensors that I'm using do have a SPI bus interface, so I think I might be able to directly connect one of these chips to each sensor? I only have 5 sensor nodes connected to the Raspberry Pi in my star topology, so I believe I'm well within the constraints on the number of nodes the CAN bus can support. The question would be then how to configure the rest of the bus. Would I simply connect one end of a Cat 5 cable to one of the CAN-to-SPI chips? The wire would then run 20-30 m to the Raspberry Pi. Could I then add one more chip at the Raspberry Pi to "invert" the conversion an communicate with the Raspberry Pi? Would there be a way to connect all five nodes to the same interface/chip? I don't think the Raspberry Pi has a native CAN bus support, but obviously does have SPI (I think you can only connect two devices?). If those chips could be added on the sensor nodes, what would be needed to interface the Raspberry Pi?
EDIT\_2:
After gathering further knowledge from everyone's feedback (thanks), I decided to keep digging. To no surprise, I came across yet another potential solution! I was reading through the comments on one of the [links I pointed to above](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/), and someone mentioned a [PCA9615 chip](https://www.nxp.com/docs/en/data-sheet/PCA9615.pdf). A quick Google search on this chip introduces "differential I²C". From a layman point of view, this sounds like a solution which wouldn't require me to change my software. Aside from that, I don't fully know the pros/cons or if it meets my three requirements listed. I will read further into the datasheet, but if anyone has feedback on this solution, I'm all ears! | 2018/07/05 | [
"https://electronics.stackexchange.com/questions/383195",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/125775/"
] | I suspect there are other kinds of I2C extenders but I am only familiar with two - buffers (like PCA9605, P82B715) and splitters (like PCA9600, P82B96). They all designed to isolate higher bus capacitance of the long runs by increasing sinking capability of the outputs. It seems the buffers all approaching EOL now.
Note, however, that increasing sinking capability basically means increasing currents, which does not bode well with your requirement of low power consumption.
There are many application notes that I'd recommend reading, like already suggested by @ali-chen [AN11084](https://www.nxp.com/docs/en/application-note/AN11084.pdf) or [AN11075](https://www.nxp.com/docs/en/application-note/AN11075.pdf), [AN10658](https://www.nxp.com/docs/en/application-note/AN10658.pdf). Interesting though, that even those of them that use twisted pairs in their topology still rely on single-ended signalling. I am pretty sure that whatever application note or device you would choose should work well.
What I would like to suggest though, is taking a look at [this device](https://sandboxelectronics.com/?product=pca9600-differential-i2c-long-cable-extender-with-buck-convertor-and-rj45-adaptor) first. They describe it as "PCA9600 extender". However buried deep inside the technical description you can find clever use of CAN transceiver chip [PCA82C251](https://www.nxp.com/docs/en/data-sheet/PCA82C251.pdf) to transform I2C signals (split to Tx, Rx by PCA9600) into differential signals.
The above already has an advantage of high noise immunity without any shielding. And it can give you high speed communication over 100 m distances. But here is another trick for you - CAN bus can operate at 3.3V with same speed and reliability as at 5V, while at the same time reducing power consumption by more than 50%. I think this justifies a closer look for your application. | I also argue to look at [this](https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling). <https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling>
It is immune to common mode noise, independent of ground connection and also runs for a few 10s of meters easily still providing high bit rate compared to I2C standard.
If you can provide the schematics it block diagram of intended connection, a better scheme can be worked out to lower power consumption further.
M LVDS (multi LVDS) can be the right candidate. You can use individual channels for I2C clock and data.
Data line is bidirectional but possible to handle via arbitration. |
383,195 | SUMMARY:
Here is what works:
*Raspberry Pi (I²C) <-> 1 m cable <-> sensor (I²C)*
Here is what I'm trying to do (doesn't work, hence question):
*Raspberry Pi (I²C) <-> 30 m cable <-> sensor (I²C)*
The "equation" to solve is thus:
*Raspberry Pi (I²C, SPI, and other) <-> X <-> 30 m cable <-> Y <-> sensor (I²C/SPI)*
Solve for X and Y
DETAIL:
I'm working with a bunch of sensors configured in a star network/topology.
[](https://i.stack.imgur.com/71MsR.png)
A Raspberry Pi Zero is used as a central "hub", where all the sensor data is collected and processed. All the sensors are the same and use an I²C protocol (they also offer an SPI bus interface). That being said, I currently have an I²C multiplexer connected to the Raspberry Pi Zero to enable multiple devices configured with the same I²C hardware address. All sensors are wired to the Raspberry Pi Zero, using 26/4 shielded cable. Everything currently works as intended.
Having the proof of concept in place, I now want to extend the reach of the star network/topology by 20-30 m on each sensor-hub connection. I thought I could just use longer wire, but apparently the I²C protocol limits the length of wire extension. I've read [various tricks/solutions](https://forum.arduino.cc/index.php?topic=57604.0) on how to extend the length, such as lowering the frequency, changing resistors, etc.
I'll be honest; I'm not an electrical engineer, so some of that stuff seems a bit more advanced, and I don't really have the knowledge or tools to assess the effectiveness of those types of altercations.
Anyway, I've done some digging, and I've found various chips I can potentially implement as more of a "plug and play" solution. That being said, much of the material I read was from years ago, and I don't know if those solutions are still viable. Here are the chips I've found
* P82B96, which apparently has a successor: PCA9600?
* P82B715
Comparing the two, I've read the first item is more versatile. I've also read the second item is older and [requires a lot of power](https://www.hackster.io/chipmc/extend-the-reach-of-your-i2c-sensor-simply-and-inexpensively-ea6b53), making remote deployments (battery powered) less practical. I recently came across another solution, where you use an [I²C to 1-wire converter](https://www.maximintegrated.com/en/products/interface/controllers-expanders/DS28E17.html) since the 1-wire protocol isn't as sensitive to increases in wire length
* DS28E17 (and potentially add DS2484 at hub)
This seems like a potential solution, but I haven't heard much about it being used by others. The only source of information I got was from the company webpage and videos. If I read the datasheet correctly, the solution doesn't require much power either. I'm wondering if others are buying what they're selling and if it works?
Anyway, again, I'm not an electrical engineer, so I could really use some advice. It seems like the I²C protocol is what a lot of sensors are using (at least the DIY embedded market), so [I imagine I'm not the only one facing the issue of extending the I²C communication](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/).
Here are my solution requirements:
* extend each sensor out from the central hub 20-30 m
* must be wired connection
* low power consumption (I'm running the network on battery power)
EDIT:
I've done some more digging over the weekend and I've come across [this chip set](https://www.mouser.com/Microchip/Semiconductors/Interface-ICs/CAN-Interface-IC/MCP2542-Series/Newest-Products/_/N-45lu7?P=1y9ix0wZ1z0zl2w&gclid=EAIaIQobChMI5NzAw7yO3AIVgcpkCh0caArzEAAYASAAEgIScvD_BwE) (MCP25\*), which sounds like a CAN-to-SPI interface. THIS WON'T WORK...SEE @Maple's comments below. I'm certainly not saying that's the only chip set offering this conversion, it's just the first one I came across. The sensors that I'm using do have a SPI bus interface, so I think I might be able to directly connect one of these chips to each sensor? I only have 5 sensor nodes connected to the Raspberry Pi in my star topology, so I believe I'm well within the constraints on the number of nodes the CAN bus can support. The question would be then how to configure the rest of the bus. Would I simply connect one end of a Cat 5 cable to one of the CAN-to-SPI chips? The wire would then run 20-30 m to the Raspberry Pi. Could I then add one more chip at the Raspberry Pi to "invert" the conversion an communicate with the Raspberry Pi? Would there be a way to connect all five nodes to the same interface/chip? I don't think the Raspberry Pi has a native CAN bus support, but obviously does have SPI (I think you can only connect two devices?). If those chips could be added on the sensor nodes, what would be needed to interface the Raspberry Pi?
EDIT\_2:
After gathering further knowledge from everyone's feedback (thanks), I decided to keep digging. To no surprise, I came across yet another potential solution! I was reading through the comments on one of the [links I pointed to above](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/), and someone mentioned a [PCA9615 chip](https://www.nxp.com/docs/en/data-sheet/PCA9615.pdf). A quick Google search on this chip introduces "differential I²C". From a layman point of view, this sounds like a solution which wouldn't require me to change my software. Aside from that, I don't fully know the pros/cons or if it meets my three requirements listed. I will read further into the datasheet, but if anyone has feedback on this solution, I'm all ears! | 2018/07/05 | [
"https://electronics.stackexchange.com/questions/383195",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/125775/"
] | The Onewire solution with the DS28E17 is the one which works mostly out of the box. You may even use the bitbanging host (e.g. on GPIO4) and get away with almost no extra hardware. Each DS28E17 on the bus is automatically appearing as an I²C host adapter, no software changes needed. Drawbacks:
* The Onewire has to be a bus, not a star. If you had a star layout, use lobes to make it a physical bus. Or use several Onewire buses, the DS2482-800 offers eight.
* It's low-speed, just about 15kBaud with a lot of overhead. You cannot use it for high-throughput sensors.
Forget about the *DS2484 behind a DS28E17* idea. That simply squares the overhead so much sending a few bytes takes a second or so. (DS28E17 behind a DS2484 or DS2482-800 in contrary is the intended use and avoids bitbanging.)
The reason that chip isn't much used by other people yet is it came out just in 2016 and the Linux driver is available just since kernel 4.15.
(And a caution: The DS28E17 is a 3.3V only device.) | I also argue to look at [this](https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling). <https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling>
It is immune to common mode noise, independent of ground connection and also runs for a few 10s of meters easily still providing high bit rate compared to I2C standard.
If you can provide the schematics it block diagram of intended connection, a better scheme can be worked out to lower power consumption further.
M LVDS (multi LVDS) can be the right candidate. You can use individual channels for I2C clock and data.
Data line is bidirectional but possible to handle via arbitration. |
383,195 | SUMMARY:
Here is what works:
*Raspberry Pi (I²C) <-> 1 m cable <-> sensor (I²C)*
Here is what I'm trying to do (doesn't work, hence question):
*Raspberry Pi (I²C) <-> 30 m cable <-> sensor (I²C)*
The "equation" to solve is thus:
*Raspberry Pi (I²C, SPI, and other) <-> X <-> 30 m cable <-> Y <-> sensor (I²C/SPI)*
Solve for X and Y
DETAIL:
I'm working with a bunch of sensors configured in a star network/topology.
[](https://i.stack.imgur.com/71MsR.png)
A Raspberry Pi Zero is used as a central "hub", where all the sensor data is collected and processed. All the sensors are the same and use an I²C protocol (they also offer an SPI bus interface). That being said, I currently have an I²C multiplexer connected to the Raspberry Pi Zero to enable multiple devices configured with the same I²C hardware address. All sensors are wired to the Raspberry Pi Zero, using 26/4 shielded cable. Everything currently works as intended.
Having the proof of concept in place, I now want to extend the reach of the star network/topology by 20-30 m on each sensor-hub connection. I thought I could just use longer wire, but apparently the I²C protocol limits the length of wire extension. I've read [various tricks/solutions](https://forum.arduino.cc/index.php?topic=57604.0) on how to extend the length, such as lowering the frequency, changing resistors, etc.
I'll be honest; I'm not an electrical engineer, so some of that stuff seems a bit more advanced, and I don't really have the knowledge or tools to assess the effectiveness of those types of altercations.
Anyway, I've done some digging, and I've found various chips I can potentially implement as more of a "plug and play" solution. That being said, much of the material I read was from years ago, and I don't know if those solutions are still viable. Here are the chips I've found
* P82B96, which apparently has a successor: PCA9600?
* P82B715
Comparing the two, I've read the first item is more versatile. I've also read the second item is older and [requires a lot of power](https://www.hackster.io/chipmc/extend-the-reach-of-your-i2c-sensor-simply-and-inexpensively-ea6b53), making remote deployments (battery powered) less practical. I recently came across another solution, where you use an [I²C to 1-wire converter](https://www.maximintegrated.com/en/products/interface/controllers-expanders/DS28E17.html) since the 1-wire protocol isn't as sensitive to increases in wire length
* DS28E17 (and potentially add DS2484 at hub)
This seems like a potential solution, but I haven't heard much about it being used by others. The only source of information I got was from the company webpage and videos. If I read the datasheet correctly, the solution doesn't require much power either. I'm wondering if others are buying what they're selling and if it works?
Anyway, again, I'm not an electrical engineer, so I could really use some advice. It seems like the I²C protocol is what a lot of sensors are using (at least the DIY embedded market), so [I imagine I'm not the only one facing the issue of extending the I²C communication](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/).
Here are my solution requirements:
* extend each sensor out from the central hub 20-30 m
* must be wired connection
* low power consumption (I'm running the network on battery power)
EDIT:
I've done some more digging over the weekend and I've come across [this chip set](https://www.mouser.com/Microchip/Semiconductors/Interface-ICs/CAN-Interface-IC/MCP2542-Series/Newest-Products/_/N-45lu7?P=1y9ix0wZ1z0zl2w&gclid=EAIaIQobChMI5NzAw7yO3AIVgcpkCh0caArzEAAYASAAEgIScvD_BwE) (MCP25\*), which sounds like a CAN-to-SPI interface. THIS WON'T WORK...SEE @Maple's comments below. I'm certainly not saying that's the only chip set offering this conversion, it's just the first one I came across. The sensors that I'm using do have a SPI bus interface, so I think I might be able to directly connect one of these chips to each sensor? I only have 5 sensor nodes connected to the Raspberry Pi in my star topology, so I believe I'm well within the constraints on the number of nodes the CAN bus can support. The question would be then how to configure the rest of the bus. Would I simply connect one end of a Cat 5 cable to one of the CAN-to-SPI chips? The wire would then run 20-30 m to the Raspberry Pi. Could I then add one more chip at the Raspberry Pi to "invert" the conversion an communicate with the Raspberry Pi? Would there be a way to connect all five nodes to the same interface/chip? I don't think the Raspberry Pi has a native CAN bus support, but obviously does have SPI (I think you can only connect two devices?). If those chips could be added on the sensor nodes, what would be needed to interface the Raspberry Pi?
EDIT\_2:
After gathering further knowledge from everyone's feedback (thanks), I decided to keep digging. To no surprise, I came across yet another potential solution! I was reading through the comments on one of the [links I pointed to above](https://hackaday.com/2017/02/08/taking-the-leap-off-board-an-introduction-to-i2c-over-long-wires/), and someone mentioned a [PCA9615 chip](https://www.nxp.com/docs/en/data-sheet/PCA9615.pdf). A quick Google search on this chip introduces "differential I²C". From a layman point of view, this sounds like a solution which wouldn't require me to change my software. Aside from that, I don't fully know the pros/cons or if it meets my three requirements listed. I will read further into the datasheet, but if anyone has feedback on this solution, I'm all ears! | 2018/07/05 | [
"https://electronics.stackexchange.com/questions/383195",
"https://electronics.stackexchange.com",
"https://electronics.stackexchange.com/users/125775/"
] | The Onewire solution with the DS28E17 is the one which works mostly out of the box. You may even use the bitbanging host (e.g. on GPIO4) and get away with almost no extra hardware. Each DS28E17 on the bus is automatically appearing as an I²C host adapter, no software changes needed. Drawbacks:
* The Onewire has to be a bus, not a star. If you had a star layout, use lobes to make it a physical bus. Or use several Onewire buses, the DS2482-800 offers eight.
* It's low-speed, just about 15kBaud with a lot of overhead. You cannot use it for high-throughput sensors.
Forget about the *DS2484 behind a DS28E17* idea. That simply squares the overhead so much sending a few bytes takes a second or so. (DS28E17 behind a DS2484 or DS2482-800 in contrary is the intended use and avoids bitbanging.)
The reason that chip isn't much used by other people yet is it came out just in 2016 and the Linux driver is available just since kernel 4.15.
(And a caution: The DS28E17 is a 3.3V only device.) | I suspect there are other kinds of I2C extenders but I am only familiar with two - buffers (like PCA9605, P82B715) and splitters (like PCA9600, P82B96). They all designed to isolate higher bus capacitance of the long runs by increasing sinking capability of the outputs. It seems the buffers all approaching EOL now.
Note, however, that increasing sinking capability basically means increasing currents, which does not bode well with your requirement of low power consumption.
There are many application notes that I'd recommend reading, like already suggested by @ali-chen [AN11084](https://www.nxp.com/docs/en/application-note/AN11084.pdf) or [AN11075](https://www.nxp.com/docs/en/application-note/AN11075.pdf), [AN10658](https://www.nxp.com/docs/en/application-note/AN10658.pdf). Interesting though, that even those of them that use twisted pairs in their topology still rely on single-ended signalling. I am pretty sure that whatever application note or device you would choose should work well.
What I would like to suggest though, is taking a look at [this device](https://sandboxelectronics.com/?product=pca9600-differential-i2c-long-cable-extender-with-buck-convertor-and-rj45-adaptor) first. They describe it as "PCA9600 extender". However buried deep inside the technical description you can find clever use of CAN transceiver chip [PCA82C251](https://www.nxp.com/docs/en/data-sheet/PCA82C251.pdf) to transform I2C signals (split to Tx, Rx by PCA9600) into differential signals.
The above already has an advantage of high noise immunity without any shielding. And it can give you high speed communication over 100 m distances. But here is another trick for you - CAN bus can operate at 3.3V with same speed and reliability as at 5V, while at the same time reducing power consumption by more than 50%. I think this justifies a closer look for your application. |
9,181 | On a 2001 Honda S2000 (or any other car for that matter) does the intake manifold cover (plastic piece held on with two 10mm acorn nuts) actually protect against something, or is it purely aesthetic? | 2014/03/28 | [
"https://mechanics.stackexchange.com/questions/9181",
"https://mechanics.stackexchange.com",
"https://mechanics.stackexchange.com/users/3729/"
] | I've had luck cleaning Mouldy Vinyl with scrubbing bubbles spray.
My car is also trashed, and has cheap vinyl inside, and I haven't had much luck cleaning it. Your best bet is to get the vinyl replaced, because it will likely crack or go brittle soon.
As far as fabric goes, most supermarkets sell those powerful steam cleaning units, get one of those, and they work amazing for cars. It's good for cleaning out the unidentified human slime from seats. | If you are not able to get it clean enough by cleaning, you can probably pick up a complete used interior of the same color and swap it out with yours. Considering what you are getting, it shouldn't be too expensive. There may be no other way to get the smell out of the car otherwise. |
20,437 | Why do we say "Jack Shit" to mean "nothing at all"? | 2011/04/11 | [
"https://english.stackexchange.com/questions/20437",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/7214/"
] | [Etymonline](http://www.etymonline.com/index.php?search=jack%20shit&searchmode=none) reports that *Jack shit* (to mean "nothing at all") has been attested by 1974, and it is American English slang.
It doesn't report for which reason *Jack shit* is used, and not, for example, *Daniel shit*.
There isn't probably any correlation, but *Jack* is a familiar form of the given name *John*, and *john* is a word that means *toilet* (the other meaning is "a prostitute's client").
In American English, *jack* is the informal short for *jack shit*, but in other contexts it also a short for *jackrabbit*.
*Jack* is also used in names of animals that are smaller than similar kinds (e.g. *jacksnipe*). | "Jack shit" is a colloquial form of emphasis. That is, if you say either "you don't know jack" or "you don't know shit" you convey the same meaning. It's arguable whether one is more intense or threatening than the other; to my mind, that depends on context and setting. "You don't know jack shit" conveys greater force by doubling the final term. |
20,437 | Why do we say "Jack Shit" to mean "nothing at all"? | 2011/04/11 | [
"https://english.stackexchange.com/questions/20437",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/7214/"
] | I guess your question is more about the *jack* part.
In English a jack is by-name for a common person.
In British English, *jack* is a very old (13th century) term to designate the average peasant - the man at the bottom of the social pyramid. See for instance colloquial expressions such as "every man jack".
In that sense it comes from Old French "jacques" which has the same meaning - "Jacques" being a very common first name in medieval France at the time. The revolt of the French peasantry during the Hundred Years' War was famously called the "[Jacquerie](http://en.wikipedia.org/wiki/Jacquerie)" because the *jacques* were all in arms and busy burning castles.
It also gave English the word "jacket" that was then adopted back in French as "jaquette" (the lost "c" and the meaning of a typically classy suit is a tell-tale sign it does not come directly from Old French).
During the British naval supremacy period, jack was also used to designate the average seaman.
The word must have somehow passed into American English. See for instance "lumberjack" for "lumberman".
So in addition to the word "shit" symbol of something of little value, the use of jack here reinforces that meaning by referring to an average fellow of supposedly low level of sophistication or knowledge.
Another very close way to see things is that "jack-sth" is used to denote a smaller version of this something. The OED says:
>
> applied to things of smaller than the
> normal size; [...] jack-bowl,
> jack-brick, jack-fish"
>
>
>
So you get the idea: a *jack shit* is of even less value than a regular-size one (who can claim now that EL&U is not an instructive forum ?).
To redeem myself, let me just mention one of the proposed etymologies of the name "**Union Jack**" (quoted from the OED) as this is a related matter:
>
> "A ship's flag of smaller size than the
> ensign, used at sea as a signal, or as
> a mark of distinction; spec. the small
> flag which is flown from the
> jack-staff at the bow of a vessel
> (formerly at the sprit-sail topmast
> head), and by which the nationality of
> a ship is indicated, as in British
> jack, Dutch jack, French jack. In
> British use the jack has been since
> the 17th c. (except under the
> Commonwealth) a small sized ‘Union
> Flag’ of the period (Union Jack),
> which has also been, since 1707,
> inserted in the upper canton of the
> ensign; hence, the name ‘union jack’
> is often improperly applied to the
> union flag itself, when this is not
> carried or used as a jack. Every
> maritime nation has a jack of its own;
> this is usually, either as in Great
> Britain, †the German Empire, Sweden,
> and the United States, the same as the
> canton of the ensign, or, as in France
> and the Netherlands, identical with
> the ensign, only smaller". (Prof. J. K.
> Laughton.)
>
>
> | "Jack shit" is a colloquial form of emphasis. That is, if you say either "you don't know jack" or "you don't know shit" you convey the same meaning. It's arguable whether one is more intense or threatening than the other; to my mind, that depends on context and setting. "You don't know jack shit" conveys greater force by doubling the final term. |
20,437 | Why do we say "Jack Shit" to mean "nothing at all"? | 2011/04/11 | [
"https://english.stackexchange.com/questions/20437",
"https://english.stackexchange.com",
"https://english.stackexchange.com/users/7214/"
] | The term "jack shit" has been around for ages. The term is a corruption of a phrase used in the British Navy. "He doesn't know jacks from sheets." Where "jacks" were flags or small sails and "sheets" were larger sails. It's not that big a step from describing a novice sailor as "not knowing jacks from sheets" to "not knowing jack shit." | "Jack shit" is a colloquial form of emphasis. That is, if you say either "you don't know jack" or "you don't know shit" you convey the same meaning. It's arguable whether one is more intense or threatening than the other; to my mind, that depends on context and setting. "You don't know jack shit" conveys greater force by doubling the final term. |
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