How about inventing a "fuel" that will not erupt into fire?

Question: One of the most concerning factor in flight safety is the possibility of the plane erupting into fire due to a fuel spill and a spark. Is it possible---or have researchers ever worked on---to power an aircraft with something that does not set the plane afire?
Comment: What makes fuel useful as, well, fuel, is that it DOES burn, thus releasing lots of energy.  It seems unlikely that one could find something you can use to power an aircraft, as fuel, which releases lots of energy when burned in the engine, but which won't do the same when burned outside of the engine.  The high flashpoint of Kerosene means that fuel spills aren't all that much of a big deal, but with sufficiently high temperatures it certainly will burn. Nuclear propulsion has been tried, but it doesn't work out well -- energy density is too low.
Comment: Lots of things will burn in the right conditions, including avgas, jet fuel, and lithium batteries. I suspect that this is fundamentally a physics/chemistry issue: if *any* substance contains a lot of energy in a limited weight/volume - which is what you need in aviation - then by definition it will 'want' to release that energy if the conditions are right. I think your question is interesting and relevant but if you don't get a good answer here you might try physics.SE and/or chemistry.SE.
Comment: Back in the 1980s NASA did some work on an additive for fuel intended to suppress the fireball that can erupt during a crash. It was called Anti Misting Kerosene. They tested it by crashing a Boeing 720 in the desert. It [didn't end well](https://www.nasa.gov/centers/dryden/multimedia/imagegallery/CID/ECN-31808.html).
Comment: @CannonFodder oh man I remember seeing that on TV!
Comment: You might try going with a bipropellant where the fuel and oxidizer are non-reactive with atmospheric oxygen. You'll at least halve the fuel efficiency of the engine, but hey, it won't burst unless you mix the two!
Comment: "One of the most concerning factor in flight safety is the possibility of the plane erupting into fire due to a fuel spill and a spark" According to whom?
Answer: Airplane engines (reciprocating/turbine) are designed to run on petroleum based fuel.  When burned, fuel releases energy in order to power the engines that were specifically designed to be powered by burning fuel.  To release its energy the fuel must necessarily "erupt" into a fire.  So, the very problem that occurs when an airplane crashes and a fuel-fed fire ensues
is the essential component (erupting into fire) that is necessary to power the engine in the first place.  If a fuel was created that would not erupt into a fire, then it would not
power the engines designed for just that purpose.
But there are other fuel centric avenues for research and development.  See a couple in the info below.

The FAA and NASA did some testing of Anti-Misting Kerosene (AMK) in 1984 and intentionally crashed a remotely piloted B720 (like a B707).  Along with some other safety improvements being tested, there was a hope that the intensity of post-crash fire using AMK would be reduced enough to permit a higher degree of passenger survivability.
Click the link below to read about the scope of the test and the less than favorable  results observed regarding the use of AMK:
controlled impact demo

After the TWA 800 fuel tank mid-air explosion in 1996, the FAA began a research effort to reduce the possibility of a future similar type event.  This eventually led in 2008 to a final rule being issued that required commercial aircraft to implement approved fuel tank "inerting" technology.  This technology essentially reduces the amount of oxygen in the fuel tank necessary to facilitate an unplanned ignition source (e.g. electrical spark) from igniting the fuel.
Although this does not change the properties of the fuel (such as adding an AMK component described above), the overall benefit of a less volatile fuel environment adds a great deal of safety.
Read about this "fuel tank inerting" here
Answer: Yes, of course, inventors and researchers have always been looking into alternative ways to power planes.

Rising air: Gliders successfully stay in the air using thermals, ridge lift, lee waves or convergence zones.
Spring power. Springs can be made of various materials including rubber and steel. Rubber spring power is still popular in toy planes
Solar power. Experimental planes have been flown successfully with  solar cells and electric motors.
Human power: The very first planes were human powered, and there are still inventors trying to push the limits
Nuclear power:

Fission: The energy density of nuclear fuel like Uranium-235 is even higher than that of chemical fuel. Experiments with fission reactors have been done up to working engine prototypes. The development has been abandoned. The radiation during operation and after waste disposable, leakage, and the risk of uncontained failure are unacceptable. Nuclear fuel does not burn, but fission reactors can melt. Sub systems containing steam can explode.
Fusion: While stationary experiments for fusion reactors are ongoing, so far no practical reactor has been implemented. Fusion does generate radiation as well, but to much less extend and risk than fission. The hot plasma in a fusion reactor cannot grow out of control. However, we still have to see a successful stationary implementation before thinking seriously about fusion powered planes.

Apparently none of first four power sources is used for commercial air transportation, because they are unreliable and/or limiting the range. Fission nuclear power could provide reliability and range, but radiation issues forbid the use of this technology. Fusion remains science fiction for time being.
Instead, chemical fuels are used because of their very high power density, their perceived abundance, and low cost.
Any power storage of high density is potentially dangerous. Just imagine a massive spring that would have enough mechanical energy stored to power a heavy long range aircraft. In case of a mechanical failure, the full amount of energy would be released in an instant. That would be just as disastrous as chemical fuel going into flames.
Answer: Treat this as you like, but one of the direct answers to this question (have researchers ever worked on to power an aircraft with something that does not set the plane afire?) is - go nuclear.
It is still possible to start a fire from overheating, but not ball of fire, and not from a sparkle. And don't worry about nuclear explosion: it is remarkably hard to make one, even having a piece of fully enriched uranium or plutonium at hand.
There will be other problems, of course, but nothing is free :)
Comment: Exactly. If there is anything to add, it would be that nuclear planes [did exist](https://en.wikipedia.org/wiki/Nuclear-powered_aircraft), and had a bunch of other interesting benefits, such as being able to stay airborne during months without "refueling."
Answer: Biodiesel has a flashpoint as high as 130-140 Celsius. This makes it far less likely to burst into flames.
Ultimately, anything useful as fuel will burn. Even batteries burn - and violently so. It's not possible to eliminate the possibility, but it's possible to greatly reduce it.
Another way to reduce this propensity is structural. There are two major parts to it: reducing the likelihood and the amount of spillage in a moderate crash; and insulating the fuselage against exterior fires.
Currently the focus is on making a post-survivable-crash fuselage survive an external fire long enough for the passengers to evacuate. Needless to say, when you're dealing with a crashed airplane, things will never go according to plan - but at least it upgrades the plan from "everyone dies" to "people die where things other than the crash itself also go wrong".
Answer:
Is it possible---or have researchers ever worked on---to power an aircraft with something that does not set the plane afire?

Yes. It's called JP-5. It's a version of JP-4, that has a higher flashpoint (60 deg C vs -18 deg C). JP-5 was developed for use by the USN, specifically to have a higher flash point for increased safety on aircraft carriers.
JP-4 has now been replaced by JP-8 (flashpoint => 38 deg. C). JP-5 is still in use.
See: this DTIC presentation.
Comment: The DTIC presentation is great!  I learned a ton from that.  Nice find.


How to fix choppy fonts after using KDE System Settings?

Question: I used KDE System Settings to configure my KDE appearance settings (I wanted to make KolourPaint look native), even though I use GNOME. I changed some font settings through it, and now all of my fonts are really choppy. Is there any way to revert these changes?
Answer: All font settings are stored in a hidden file in your home folder, called .fonts.conf.
If you remove it (in your home folder, press Ctrl + H, and delete .fonts.conf), and generate a new one, by running, in a terminal instance (Applications > Accessories > Terminal):
 sudo dpkg-reconfigure fontconfig
You then should get the usual Linux crystal clear fonts (you actually may need to log out and log back in, but that's it)
Comment: Thank you very much. This solved my problem. I honestly can't believe I didn't think of it myself.


Aegir+ Ubercart + Freetrial + ARB. Not working

Question: I'm trying to set an automated approach to do the following:

Customer signs up for a 30-day trial. Enters CC#, but is not charged for 30-days until free trial converts.
CC# is verified (but not charged) on initial registration.
CC# is NOT stored in cleartext in my database (need PCI compliance).
IF account is active (i.e. I don't manually delete account), the account will automatically recur a monthly transaction every 30-days .

I have Aegir and store Admin set up with Authorize.net. I just signed up for Auth.net ARB, but I'm unsure how I set this up to accomplish what I'm describing above. As you can see in the screenshot below, I can manually charge the CC through the Admin interface, but that would imply that I would need to go in and charge the CC# in 30-days, and then manually every 30days thereafter.... That will become unmanageable quickly... As I said, I signed up for Auth.net's ARB, but the documentation on setting this up with Drupal is pretty poor.
http://screencast.com/t/kB0xixRAerIo
Secondly, and perhaps a bigger problem with Drupal, is the fact that as the admin, I can see the customer's full CC# right there in cleartext when I click "view card details". Yikes. There must be a big mistake in all this, but don't know where.
http://screencast.com/t/Kj46n17spnRq
Should I sign up for Auth.net's CIM to capture/store/hold customer's CC# throughout free-trial period, and then charge and and convert to ARB for automated monthly charges? If so, I'm stumped on how to set this up.
And... lastly the primary issue I have is that orders are being rejected due to no Bill-to address being populated with Auth.net. The order page shows no bill-to data was recorded, but when I look at the registration side, I can see that the bill-to address info was indeed captured.
There seems to be some missing link where the bill-to address data recorded at registration is not being passed through to Auth.net (but CC# and name is being passed through). So it's the missing Bill-to data that is causing the rejection on Auth.net side. Any thoughts on why this address data is not being populated on Auth.net's side?
Thoughts/leads? we have a couple SyAd guys stumped on this. Thanks!
Answer: While this question is now 6 years old, the way to go about this nowadays is via Aegir Site Subscriptions, which isn't quite ready yet, but is on the way.  So far, there's code for Recurly, but no other recurring billers.


Which NFC tag will be suitable for my requirement

Question: I am currently working on restaurant interaction.
I require a URL and record to support AAR in my Android app.
Can anyone suggest me which tags will be suitable for this?
Please, mention the link where I can get the tag.
Answer: You can use the following webpage to determine the required size for an NFC-tag: http://nearfieldcommunication.com/developers/choosing-tags/
Because you want an URL and an AAR you should enter the wanted URL, remember the necessary amount of bytes and afterwards create an URL with the package name. Because an AAR is made out of the package name of your application and it is almost the same size in bytes as an URL add it to the amount of bytes necessary for the URL.
In this way you don't need to install the plugin and afterwards you have the option on selecting specific tags and you will get a list on were to order the NFC-tags.
Answer: Use a short package identifier, then add the data you'd like in a minimal form, like an id (to which there is more information online). Try this (shameless plug), the editor auto-computes the size for any NDEF message.


Can SP2013 Foundation be used to scale out search?

Question: My understanding is that a SP server license is required if any of the SP web services are installed, regardless of whether is a web front end or any other service. However, since the uplevel version of search is available in Foundation now, could that be used to scale out some part of the search web services without needing to add server licenses?
Answer: Search in SharePoint Foundation is restricted to be installed on one server, if you need to scale out, you need to go with Server License.


Problems installing the Ultimate Vault Hunters pack with season pass

Question: I bought the season pass for BL2. I can see all of the other DLCs that have installed but I do not see the "Borderlands 2: Ultimate Vault Hunters Upgrade Pack" that has the level cap increase. Can someone tell me how to figure out if it installed?
Comment: I looked and I'm not sure I saw it either...one way to tell would of course be to see if you can gain XP past level 50. I'll check and see if it shows listed with the other DLC tonight.
Comment: The downside is I picked up the game late and am only 45
Answer: Well it seems there is no visual indication if you only own the Season Pass:

However my BL2 did update and I quite certainly have been able to level over 50. So I would say as long as your BL2 has updated since the patch (April 2nd) and you own the Season Pass your Ultimate Vault Hunters Pack should be active.
Comment: I would have upvoted the answer as well... but I have to have 15 rep :/
Answer:
First way to fix is to dashboard and start up the game again. The game will then check for downloaded content and make it work.
Second way is to try and reinstall each download. Sometimes downloads will go contradict each other. This may be one of those cases.
Answer: I swear I remember seeing it in the list right after I installed it, but when I look at the list now, it isn't there. I would assume that it's installed on your game.
Comment: I have something called the "premier club;" but, everything else named does not say "Ult Vault Hunter Pack." Everything says that it is included in the season pass. Might it not be showing up because I haven't hit 50?
Comment: Well, that's odd... I know it was visible the other night, but I don't see it anymore. Reversing my answer...
Answer: why don't you try downloading it straight from the store instead of loading the game and download it that what I did but I'm on psn but for xbox try the same it should work too
Answer: from what I readyou have to start the game from the beginningand then it just gives younew levels and better chances to get better guns


Timing of Panda penalty

Question: I found a new site (< 2 months old) with 0 PR that already has over 500,000 pages indexed according to the site: command.    When I just do a google search on the domain name in quotes,  there are around 300,000 hits but when I search through them,  I only get 49 results before I see the 'omitted similar results' message and  the 'repeat search with the omitted results included'.   So this site is almost exclusively auto-generated and duplicate content so I am wondering why it hasn't been penalized.  I am wondering about the timing for a Panda penalty. Does Panda work after the fact?  In other words, does a site get crawled and indexed and then the Panda algorithm is applied at a later point?
Comment: Too many questions and not about a website you control.
Comment: It takes a while for Google to fill in all the blanks within it's semantics database and therefore gives a certain amount of grace to new sites. Part of the reason for this is SERP sampling to see how people react to the site. If the site is as you say, it will begin to settle into the SERPs where it belongs and penalties will be issued as they come about. It can take months, 6 or more before this happens. My advice is do not worry about another site- worry about your own. Otherwise you are taking your eye off the ball. Not being critical. Just friendly advice to help you. Cheers!!
Answer: Firstly there are times that two exactly same pages from the same site can come up in the SERP due to differences in which keywords where targeted when extracting the pages from the reverse index used by Google.
As for low long the Panda penalty takes to apply this very much depends on when it detects that the site is a duplicate. There is no hard and fast rule and as it is algorithmic there is no way at all to predict if and when it will happen.
To your last question does it happen only after the fact the simple answer is yes. Before Google's Panda algorithm can work out if a site violates the rules it first needs to crawl a site and index it. Furthermore before the duplicate content can be detected Google needs to have the original canonical site in its index as well and compare the two which is done after the fact not during crawling as it would substantially delay the crawling process which is the exact opposite of what Google is trying to achieve with all of its updates to the crawling and indexing systems.

Timing of Panda penalty


What happened to Kilopower generators?

Question: Why are we still using solar power for spacecraft? Would it be possible to replace the giant solar arrays and batteries on spacecraft with Kilopower generators?
Comment: Voted to reopen, the question is easily answerable.
Comment: Don't lose interest this is a good start.
Comment: Sometimes broad questions have broad answers. In this case, the same basic principle applies to all spacecraft.
Comment: I support launching any device called KRUSTY.
Comment: slightly related: [What was the most recent launch of a nuclear reactor, and what are the current barriers to launching the next one?](https://space.stackexchange.com/q/34139/12102)
Comment: Why solar? Well, if it solves the problem, and if the price is right... Why not?
Comment: @Hobbes looks much better! Voting to reopen...
Comment: [Nuclear Energy Our Misunderstood Friend](https://www.youtube.com/watch?v=WQpLhXLvC-4)
Answer: NASA's Kilopower project is still in its development phase.

After successful completion of the Kilopower Reactor Using Stirling Technology (KRUSTY) experiment in March 2018, the Kilopower project team is developing mission concepts and performing additional risk reduction activities to prepare for a possible future flight demonstration. Such a demonstration could pave the way for future Kilopower systems that power human outposts on the Moon and Mars, enabling mission operations in harsh environments and missions that rely on In-situ Resource Utilization to produce local propellants and other materials.

NASA is targeting 2020 for an initial in-flight demonstration.
Even when Kilopower becomes operational, it won't replace solar panels on most spacecraft soon.

Because Kilopower is a nuclear power system, it will be expensive to build and launch, which limits its applications.
NASA is targeting a system that produces 1 kW at a weight of 400 kg. In Earth orbit, solar panels can produce that power at a much lower weight: 50 W/kg, so 20 kg for 1 kW. (this ignores batteries, which you need for orbiters and ground-based applications)

Kilopower is targeted at planetary exploration: missions to Mars and the outer solar system. On Mars' surface, solar panels can be used but have drawbacks (dust accumulation, 30% lower performance than on Earth). And the further out from the Sun you get, the lower solar panel performance will be.
The ground-based Kilopower system also has a higher power/weight ratio (1500 kg/10 kW) because it can use the ground as a heat sink. This makes a comparison with solar panels more favorable.
NASA's current nuclear power source, the GPHS RTG, costs about \$65-90 million apiece (cost estimate for the New Horizons mission) and provides ~250 W at launch. The goal is to supplement this with a system that provides more power at a lower cost. So far (including the KRUSTY demo reactor which didn't have Stirling generators) NASA has spent \$20M on Kilopower development.
The RTG may still be used for some missions: it has a proven lifetime of closing in on 50 years, while NASA targets "at least 10 years" for Kilopower. Because Kilopower contains moving parts (and an RTG doesn't), it's more difficult to keep a Kilopower reactor running for very long missions (e.g. Voyager).
Comment: The problems of a lifetime of about 50 years are not only the moving parts of  Kilopower. The reactor core should remain critical but also stable and controlable over the long time despite the consumption of fissile material and the accumulation of long-lived neutron poisons. But due to the very different reactor core design many experiences from more than 70 years of reactor operation are not applicable.
Comment: Also this will depend massively on what power level the reactor is run at.

What happened to Kilopower generators?


Will I need to go through extra security when flying from one Schengen country, to another, and then to the United States?

Question: On December 20th, I am flying from Nuremberg (Germany) to Detroit (USA), with a 1 hour and 50 minute layover in Amsterdam Schiphol Airport. When I arrive in Amsterdam, will I need to go through extra airport security/immigration in order to board my flight to the USA?
Answer: Since you will leave the Schengen area at Amsterdam, you will need to go through EU exit immigration there.  Since your flight is headed to the US, you may also be asked some "security questions" at the gate and potentially have your carry-on bags briefly inspected.
 However, you should not need to go through an additional full security inspection (X-rays etc).
Comment: in the early part of the last decade (i.e., starting shortly after 11 September 2001), there were indeed extra security checks for people flying from Schiphol to the US. I suppose those don't exist anymore, but I don't remember for certain. I recently flew from Munich through Schiphol to New York, but I was tired (uncomfortable airline-provided accommodation in Bavaria) and all I remember is running because of a short connection and that the passport control officer wondered why I didn't use the e-gates (I was traveling with my wife, but she didn't wait for me after he returned her passport).
Answer: Yes. Schiphol airport has a "Schengen" and a "non-Schengen" zone. To move from one area to another you have go through security and passport control (passport control happens if you enter/leave the Schengen zone, not if you travel between countries in the Schengen zone (assuming no temporary measures)). You do not have to go land-side, you can move between the zones air-side.
On top of that, there will be a short interview for all passengers flying to the USA. For many flights, this happens at gate D1 (your boarding pass will say D1 as your boarding gate -- you'll be redirected to the appropriate gate after the interview). There is an exception for passengers flying Delta and starting their journey in Amsterdam -- for them, the interview happens right before the security check. But that does not apply to you. I once has the "pleasure" of being interviewed at gate D1 and almost missed my flight because of the long queues. But that was years ago, and shortly after they implemented the "interview everyone at the same place" (before that, the interviews happened at the gates). Since, I've either flew Delta, or via a London airport, so I've no recent experience with the mass interviewing, but I think the process is much smoother now.
Comment: To add to this: you have to go through security at AMS, but this only involves queuing up, presenting your passport, and possibly being interviewed. Your carry-on bags (and your person) will not be X-rayed as they are when you're entering the secure area from landside. And if there are long queues, they allow people with a short connection to skip to the front.
Comment: It's not necessary to go through a security checkpoint to pass from the Schengen zone to the non-Schengen zone, only through passport control.  Separately from that, passengers arriving from certain countries have to go through extra security screening.  Also, passengers departing to certain countries have to go through extra security screening.  But, for certain pairs of airports, it's certainly possible to transfer at Schiphol with only passport control, or with no passport control and no security screening.


Minecraft pocket on Hudl

Question: My son has been playing Minecraft pocket version on his Hudl for a few weeks now, but he is saying that for some reason the arrows are now doing the opposite to what they should. When he presses the down arrow it goes up, left arrow goes right and so on. Don't know if he's changed something but it is causing us all a headache. Any ideas? Thanks
Answer: Did he set the speed to -1? That causes the controls to become flipped. Try entering speed 1 and see if that fixes it.

Minecraft pocket on Hudl


Is there definite proof that Beerus is stronger than Champa?

Question: Is there definite proof that Beerus is stronger than Champa? I mean beyond someone saying that Champa is fat.
Answer: For the manga, I would say there is. Beerus participates in a fight with all the other gods of destruction. He's attacked by all the other gods of destructions together, and he manages to be one of the 2 last remaining fighters along with Kitela. For the anime, I can't comment since I dont recall statements or hints that shows he is.
Comment: I didn't notice that, he's so strong
Answer: Beerus is stronger than Champa. We know this definitely in the episode where Goku and Vegeta meet Vados and Champa for the first time. When Goku asks Vados as to which of the two was stronger, Vados clearly replied that Champa was completely out of shape and hence implying Beerus was stronger. I have attached a clip of the same here.
In the manga, Beerus is shown to be one of the strongest, if not the strongest God of destruction across the multiverse in the Chapter where all the Gods of Destructions had to fight each other.


Which methods are available for NMinimize?

Question: I can't find in the documentation the list of methods available to NMinimize[]. Is there a way to get this?
The NMinimize page in Documentation Center mentions only Method -> "DifferentialEvolution".
Comment: An other question would be: Is it possible to use something like `foo::Method` in order to know the different methods available?
Comment: If you click on "Details and Options" you'll see the whole list.
Comment: Indeed, the last bullet of that sections reads: *Possible settings for the Method option include "NelderMead", "DifferentialEvolution", "SimulatedAnnealing", and "RandomSearch".* I note that it uses the tantalizing words "possible" and "includes", suggesting there might be many more settings.
Comment: Voting to reopen. Evidently the docs aren't enough for this one
Comment: Yes, it is not very clear. I have also found on the page tutorial/ConstrainedOptimizationGlobalNumerical the following line: NMinimize and NMaximize have several optimization methods available: Automatic, "DifferentialEvolution", "NelderMead", "RandomSearch", and "SimulatedAnnealing". I assumed there could be more methods available.
Comment: You should read these tutorials [Numerical Nonlinear Global Optimization](http://reference.wolfram.com/mathematica/tutorial/ConstrainedOptimizationGlobalNumerical.html#217856200) and [Numerical Nonlinear Global Optimization Examples](http://reference.wolfram.com/mathematica/tutorial/NumericalNonlinearGlobalOptimizationExamples.html#202578656).
Comment: @b.gatessucks you can post your comment as an answer if you want and I'll accept it.
Comment: Not sure if we shouldn't close this question as it only involved a simple manual lookup.
Comment: I would close it.
Answer: The complete list of possible methods is given by Optimization`NMinimizeDump`$Methods:
Optimization`NMinimizeDump`$Methods
 (* -> {Automatic, DifferentialEvolution, NelderMead,
        SimulatedAnnealing, RandomSearch, NonlinearInteriorPoint} *)

As you can see, there is one undocumented method: NonlinearInteriorPoint. The probable reason for its being undocumented is that by itself it is not very effective as a global minimizer, so it is used instead as a postprocessing step for the other methods in order to ensure that constraints are properly enforced.


Do enemy NPCs have to use spell slots for their spells?

Question: Would an evil mage be able to spam fireballs in a combat encounter or would they run out of slots to use eventually?
Comment: I assume you mean the NPCs listed in the back of the MM?
Comment: @Slagmoth There are NPCs in the adventures, too.
Answer: Yes, NPC spellcasters (usually) use spell slots
This is covered by the explanation of monster attributes and abilities at the beginning of the Monster Manual. Spellcasting is covered on page 10 (emphasis mine):

A monster with the Spellcasting class feature has a spellcaster level and spell slots, which it uses to cast its spells of 1st level and higher (as explained in the Player's Handbook). The spellcaster level is also used for any cantrips included in the feature.

In other words, they cast spells just like the PCs do, and their description will say which spells they have and how many slots they have. (For example, the Archmage NPC (MM, p. 342) is an 18th-level spellcaster with a list of spells and slots, e.g., they have four 1st-level slots.)
Innate casters are the exception
The "usually" covers the exceptions that don't use a Spellcasting feature. These are usually more monstrous critters that don't usually get called "NPCs".
For example, a Pixie (p. 253) doesn't cast spells like a class and has no level, and has the Innate Spellcasting instead of the Spellcasting feature. Instead of casting using spell slots, they have "At will" and "1/day each" abilities that list the specific spells they can do on those terms. See the Monster Manual page 11, "Limited Usage" for details on these abilities.
Answer: NPCs built as PCs:
These would have the exact same requirements and restrictions as a PC of equivalent level and class.
NPCs built as Statblocks, such as in the Monster Manual:
These usually have an indication, under a header such as "Innate Spellcasting", with the spells they know and the number they can cast per day. Alternatively, they may have a spells known chart, with a number of slots available for that spell level.
In general, Monsters and NPCs are built with limitations to spellcasting, although some may have Spell like abilities or Actions that function as a spell which they may use an unlimited number of times per day.
The Evil Mage statblock from the Starter Set does have limited spells per day, as outlined in it's Spellcasting section.
Building a Mage NPC:
If you were planning to build a Mage NPC, it is up to you how you assign abilities, spells, and attribute points. When designing a spellcasting NPC however, you must take special care to properly calculate the challenge they will represent due to the spells they have access to, in addition to their at will abilities.
Answer: The NPCs in the back of the MM have spell slots listed along side the typical spells they have available. Example from the Archmage on MM p342

2nd level (3 slots): detect thoughts, mirror image, misty step
3rd level (3 slots): counterspell, fly, lightning bolt
4th level (3 slots): banishment, fire shield, stoneskin
5th level (3 slots): cone of cold, scrying, wall of force
6th level (1 slot): globe of invulnerability

They follow the same rules as the PCs if they cast a spell of a given level they utilize a slot for said spell. Exceptions would be if the entry indicated that it would not cost a slot to cast, Catrips for example or innate casting with usages per day. Admittedly, since the NPCs are mostly humanoids of playable types you won't find many of those.
Answer: Spell casting NPCs in the back of the MM, PHB, or VGtM list the level of the spells, number of spell slots, and known spells.  Monstrous creatures often have 1/day, 3/day, or at will spells listed in their spell blocks.
You can also chose to build NPCs with PC levels, in which case you can follow the PC rules for spell casting.
Of course, being the DM, you can chose to make an NPC with a stronger or weaker spell casting regimen, based on if you want them to feel stronger or weaker than the players (be careful about significantly changing the number of high levels spells).

Additionally, you might consider allowing different rules for non-combat spell casting.  For example, in my homebrew world, most clerics are not fighting types. Sure there are adventurers bestowed with power from the Gods like the cleric class, but most "clerics" my PC's meet aren't NPC's with PC levels, they're NPCs who can cast any non-combat cleric spell "at will" (takes them like 1-5 minutes to cast a 1 action spell though).
By the same token, most wizards can't cast while simultaneously avoiding arrows, swords, and enemy fireballs. Most probably couldn't even cast fireball without consulting a spell scroll (even if they understand the concepts behind it). They can, however, enchant items, teleport people, and cast other "non-combat" spells at a much higher frequency (and potentially faster) than their combat oriented colleagues.
A good comparison to real life is comparing a member of the Army Corp of Engineers (ACE) to an Army Sapper. Sappers are specialized in a few military applications of engineering (bridge building, explosives sizing and use, etc...), and can preform those tasks quickly and effectively in high pressure situations. They are less skilled at long term, large, complex engineering projects. An ACE, on the other hand, is more versatile in their known subject matters, and can better build more complex designs. They would be next to useless in a high pressure/low time situation though (in comparison to the Sapper who has military training).


Will windows 8 apps work on windows phone 8?

Question: Windows phone 8 will probably have a larger installed base than windows phone right of the bat, so cool apps like gmail, google maps etc will soon be available on that. How easy is it for app developers to make their windows 8 apps available on windows phone 8 platform?
Answer: It depends on the complexity of the application, but if you are writing a "Metro UI" application on Windows 8 then porting may be relatively easy:

If you have a game written in C++/DirectX or an app that works inside
  an IE control, it should be easy to port to Windows Phone 8. For
  everybody else going from Windows 8 to Windows Phone 8, you've got a
  whole lotta re-imagining and re-coding to do.
Answer: Until Microsoft publicly releases details on how to write applications for Windows Phone 8, there can only be speculation; What is known is that there are some differences between Windows Store style applications, and Windows Phone Apps, that mean developers will have to download additional tools to target Windows Phone devices.
It has been said that the vast majority existing Windows Phone Apps will continue to work on Windows Phone 8 (so it may actually have more apps at launch) - there are caveats if developers have tried to be sneaky to expose something they shouldn't have access to.
Answer: Until the SDK formally releases, deep details aren't available.
But you will not be able to directly take an executable binary from Win8 to WinPhone8.
If you're looking at doing layers that are portable between Win8 and Windows Phone, spend some time studying how to use the Portable Class Library Project in Visual Studio 2012.  Key piece of portable.  Here's a link to get you started - http://msdn.microsoft.com/en-us/library/gg597391.aspx .  Pay special attention to the "Supported Features" chart.
Here's a primer from MSDN Mag - http://msdn.microsoft.com/en-us/magazine/hh335063.aspx .
This channel9 video has a ton of resource - http://channel9.msdn.com/Shows/Visual-Studio-Toolbox/Visual-Studio-ToolboxPortable-Class-Libraries .


GRUB geom error trying to install Linux

Question: Tried installing Linux (Red Hat 5) along with Windows 7. I created a new partition (10 GB in size) and used it for the Linux installation. After install, I was getting GRUB geom error and my system wasn't booting.
After a few tries I had to format my entire hard disk and run fixmbr which came up with the following warning message:

A new MBR will be created and some of the partition may become inaccessible

Now, even though I have gotten back Windows, the Linux partition is not at all visible. (Seems like the warning message has become a reality as that partition looks like has become inaccessible.)
My new hard disk capacity has also reduced by 10 GB and it is not showing up using any software.
How can I recover that inaccessible partition?
Edit
I tried fdisk via Linux Rescue disk. Got an error 22, the details as follows:
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 22: Invalid argument
The kernel still uses the old table.
The new table will be used at the next reboot.

No luck booting in Windows.
Comment: "red hat 5"? RHEL 5?
Answer: Boot up with a Linux live or rescue disk, run fdisk, and delete the 10GB partition from there.
Answer: Super Grub is awesome. It'll fix your boot loader.
http://www.supergrubdisk.org/
Burn the ISO to a disk, stick it in your drive, reboot, boot from disk, follow the instructions. Works like a charm. :)

GRUB geom error trying to install Linux


Delighting narrow-to-region possible?

Question: I want to delight narrow-to-region. When I call org-toggle-narrow-to-subtree it calls org-narrow-to-subtree which calls narrow-to-region. When this is called the modeline shows "Narrow". Is there a way to delight that? I would like to replace that with a unicode character, which I did with minor modes. Help tells me that narrow-to-region is a c function an not lisp. Does this mean no delighting possible?
Answer: No, delight can't affect the appearance of "Narrow" in the mode line, because it is not a mode name/lighter (despite appearing in the same section of the mode line).
Only major mode names and minor mode lighter text can be Delighted.
The mode line syntax %n is what produces the word "Narrow" (when appropriate), and that appears in the mode-line-modes variable -- which is one of the components of the overall C-hv mode-line-format (see which) -- following the list of minor modes.  The string " Narrow" is hard-coded in the C code for formatting the mode line.
Your options are probably:

Remove the %n entirely (and optionally add a custom replacement).
Do some post-processing of the formatted mode line to search and replace the text " Narrow"

For the latter, I have a feeling that one of the alternatives to delight works by performing the user's desired search/replacements on the formatted mode line whenever it is rendered, but I can't recall the name of that library.
For the former, you could use something like the following, to replace the "%n" in mode-line-modes with the following mode line construct:
(:eval (when (buffer-narrowed-p) " <N>"))
That's necessarily less efficient than the C code, but I can't imagine it being noticeable.
;; Replace "Narrow" with "<N>" in mode line, when narrowed.
(defvar my-mode-line-narrowed " <N>"
  "Appears in the mode line when the buffer is narrowed.")
(catch 'done
  (let ((x mode-line-modes))
    (while x
      (when (and (stringp (car x)) (string= (car x) "%n"))
        (setcar x '(:eval (when (buffer-narrowed-p) my-mode-line-narrowed)))
        (throw 'done t))
      (setq x (cdr x)))))

You can then M-: (setq my-mode-line-narrowed "foo") RET to play with different indicators.
Answer: Similar to @phils's answer, but skipping the explaining, which he's done well.
(defun remove-Narrow-lighter ()
  "Remove `Narrow' lighter from mode line."
  (let ((%n-cons  (regexp-car-member "%n\\(.*\\)\\'" mode-line-modes)))
    (when %n-cons (setcar %n-cons ""))))

(defun regexp-car-member (regexp xs)
  "Like `member', but tests by matching REGEXP against cars."
  (and (consp xs)  (if (and (stringp (car xs))  (string-match-p regexp (car xs)))
                       xs
                     (regexp-car-member regexp (cdr xs)))))

I do something similar to this in zones.el, but to change the narrowing lighter to reflect the current narrowing (zone), not to remove it altogether.
(FWIW, I don't recommend removing this lighter altogether, as it's usually important to know when the buffer is narrowed.)

Delighting narrow-to-region possible?


Why are higher-energy bonds preferred over lower-energy ones?

Question: My chemistry book states that for example the bond S-O is preferred over the bond S-S because the first has a bond energy that is almost twice as the second one. Since the energy released by the formation of the bonds is equal to the energy needed to let the reaction occurr,why does stronger bond are preferred over lower ones?
I mean, if a S atom needs let's say 170 kJ/mol to start a reaction with another S, shouldn't this be more likely to happen respect to a bond S-O that needs 340 kJ/mol?
Comment: more energy released means more energy required to break the bond and if more energy is required to break the bond the bond is stable.I let you conclude from there.
Answer: When a mole of $\ce{S-O}$ bond is formed, $340$ kJ of heat is released.
This $340$ is not how much energy is needed to start a reaction. That energy (activation energy) cannot be derived from the bond dissociation energy.
Comment: Oh thank you I didn't understand very well. I was very confused with the bonds energy.
Answer: The energy in forming a bond is heat released, and so must be absorbed when breaking a bond to form separate atoms. To see if  one type of molecule will react with another we compare the heats of formation (approx. sum of bond strengths) to obtain a heat of reaction. If negative the reaction is exothermic then heat is released on reaction so products have lower energy and are more stable than reactants or if not then the reaction is endothermic which is the other way round.
The heat of reaction does not tell us whether the reaction is going to be fast or slow. This depends on the activation energy, which is a potential energy barrier between reactants and products, and has to be overcome if reaction is to occur. The more frequently this happens the faster the reaction. The activation barrier exists only very briefly, and is caused by rearranging the atoms in the reactive molecules, after they have collided with one another, and as new molecules are formed.


Attenuate frequency bin in FFT array resulting in artifacts

Question: Am trying to remove noise for certain frequency bands by attenuating freqeuncy bins in the FFT array. However this results in artifacts to be formed, where there are clicking sounds in between each frame. Im already using a frame length of 1024 with 50% overlapping hamming window at 48000 sampling rate. How do I remove the artifacts while still being able to suppress the noise?
Comment: filtering and spectrograms are different although not incompatible operations.
Answer: You do not want to do the filtering in the frequency domain with essentially a brick wall filter. A perfect rectangular brick wall filter needs infinite support in the time domain. In practice, this isn't possible so your filter coefficients ( the sinc function ) will be truncated. This is fine unless you need these segments to fit back together (audio processing, etc) because at the transitions it will not be well behaved. This is because zeroing a bin / or attenuating a bin is essentially adding a sinusoid with opposite phase and magnitude into your signal. The fft only picks up exactly periodic frequencies in your signal, all other signals will be 'spread' across the spectrum so in attenuating the exactly periodic bins you are adding sinusoids with opposite phase and magnitude to your signal and these are all adding up with the other signals in your signal to be ill behaved (not perfectly continuous) at the frame boundaries.
Comment: what method would you suggest to remove the noise then?
Comment: Filter in the time domain
Comment: would it be the same if you multiply the fft array with the transfer function of a filter in the frequency domain? Ive tried using a butter filter function in Matlab, filtering in the time domain. The artifacts are reduced, however, it seems to apply a window on the filtered speech signal, resulting in the voice to sound robotic, due to some harmonics being removed
Comment: I'll point you to this thread which might clear up some questions: https://stackoverflow.com/questions/34581355/frequency-domain-filter-vs-iir-and-fir-filter
Answer: If your FFT is not zero-padded, then your frequency domain filtering will result in a circular convolution, where the end of your filter's impulse response will corrupt the beginning of each FFT/IFFT window of data, and likely produce artifacts at each frame boundary.
If you zero-pad your FFT by the length of the impulse response of your filter, then you can use overlap-add or overlap-save fast convolution to concatenate the tail of the impulse response of each filtered frame into subsequent windows where they belong (instead of a circular corruption).
Note that just zero-ing FFT bins is the same as a brick-wall rectangular filter which has an infinite impulse response, thus will usually corrupt your data, even with a lot of added zero padding.  So a more reasonable filter kernel (with a finite length impulse response) is required to do FFT filtering.


How did this affect Thanos and Hulk differently?

Question: In Avengers: Endgame, when Hulk wore all the Infinity Stones he was instantly getting major injury before he even snapped just by putting on the gauntlet. Whereas Thanos in Avengers: Infinity War was able to wield and use all 6 (not all of them at once) without injury (until he snapped). Is this because the nano gauntlet and the IW gauntlet are different?
Comment: Tony didn't care about the safety of the wielder, whereas Dwarves did.
Comment: @ILoveYou3000 That seems so far fetched I highly doubt it is true. And in fact Tony is _more likely_ to care for the safety of whoever wears it than Eitri is for Thanos.
Comment: @TheLethalCarrot Only if he could fully reverse engineer the original Gauntlet. It's not easy to build perfect product. People often overlook things.
Comment: @ILoveYou3000 So you're saying Tony didn't care for the safety of the wielder because he couldn't build a perfect product and overlooked things? You seem to be adding 2 and 2 together to make 5.
Comment: @ILoveYou3000 I don't even know how to reply to that, that's just.... yeah.
Comment: @ILoveYou3000 I think it's more likely that Tony and Bruce are simply less capable than three hundred magic space dwarves and their ancient star forge.
Comment: @TheLethalCarrot Seat belts are designed to protect passengers during car crash. But, the same belt can trap you inside water. A perfect car should automatically retract belts if car starts to submerge in water (an alien car possibly). An engineer who cares more on safely than functionality would give alien car's every feature attention.
Comment: Thanos != Hulk, Thanos did defeat Hulk pretty easily in Infinity War
Answer: Because Thanos is stronger than the Hulk.
The screenwriters Christopher Markus and Stephen McFeely have said in previous interviews that Thanos is simply stronger than Hulk, that is why he could beat him so easily at the start of Avengers: Infinity War.

I think he could. I may be speaking out of turn, but I think Thanos could kick the Hulk's ass without the (Power Stone).
[...]
We want to announce Thanos as the biggest villain in the MCU, so he takes out the previous reigning champion. And by defeating Hulk relatively easily and savagely, hopefully there's a sense of dread over the course of the rest of the movie for anyone else who comes up against him.
MovieWeb, Infinity War Writers Say Thanos Could've Beaten Hulk, Power Stone or Not

On top of this Hulk is struggling a lot longer with the Gauntlet on because he is fighting the Infinity Stones to try and bring Nat back but it wouldn't let him. I.e. his snap was more than just a quick "kill 50% of all life" but a back and forth fight.

Bruce: You know, I tried. When I had the gauntlet, the stones, I really tried to bring her back.
Avengers: Endgame

His snap attempt is instant, as in he puts the Gauntlet on and instantly starts trying to bring Nat back and do the snap. Had he left it on for a bit before attempting the snap the effects probably would have died down as we see when Thanos wears it.
Of course the two Gauntlets are different as well, made of different materials and designs. One would speculate that whilst the Infinity Gauntlet is probably made of a stronger material (Uru most likely but it's never mentioned), the Stark Gauntlet is an improved-upon design. Note that Tony, Professor Hulk and Rocket oversee its creation and they all incredibly clever. They've all also come into contact with The Infinity Stones before, and Tony and Banner also made extended analysis of the Mind Stone.
They also probably have the Infinity Gauntlet to look at after Thanos' death so can reverse engineer that. It's likely that the Stark Gauntlet could even be a better version than the original.
Comment: Your last inference is wrong. Bruce tried to bring her back at the time of the snap.
Comment: @ILoveYou3000 Which is what my point is. Edited to clarify a bit though.
Comment: But, the question asks about the duration before the snap.
Answer:  1. Different Gauntlet composition
The gauntlet in Infinity War (Thanos-Gauntlet) was forged by Eitri, the Dwarf King using

Uru (the metal used to make Mjolnir).

The material used to make the Iron-Gauntlet on the other hand isn't specified but it's speculated to be made using

Vibranium, the strongest metal on Earth

 2. Hulk vs. Thanos
As seen during the fight between the two in the beginning of Infinity War, and as mentioned by MovieHub here, Thanos is way more powerful (both mentally and physically) than The Hulk.
Answer: Thanos is often stated to be the most powerful being in the universe before getting the stones. Hulk is just a gamma victim.
Comment: If you could [edit] in one of the relevant quotes this would greatly improve the answer.


Find a string that I entered in ollydbg

Question: Say, there's an input box and I enter a text. Can I somehow find the location that text is entered?
Answer: Set breakpoints on GetWindowText() and GetDlgItemText() and have the target program read your input text. If the breakpoint is hit, you can trace up the call-stack to
see what code is reading your input text and where in memory it's being stored. If neither breakpoint is hit, you can try setting a conditional breakpoint on SendMessage(), filtering it to only break on the WM_GETTEXT message.
If the above methods fail, you may want to statically analyze the program to find where it's creating the text box window and how it's handling input to the text box. Searching for window creation API calls and/or cross-references to strings related to the text box (static labels, error message strings, etc.) can be helpful.
Answer: In addition to what Jason said, I'd add that there is another potentially helpful way:

Breakpoint on ExitProcess() (and probably HeapFree() too)
Enter in the input box some test - "bla bla bla"
Search the memory of the process for that string and try to analyze the code that is referencing that place.

I agree that this could be an overkill, but still could be helpful in some situations.
Answer: in addition to all the above solutions after you have entered your text string press f12 and pause the debuggee
now there are several options to search for the string
view call stack (ctl+k) and set a break point on the return address in the stack and press f9  to run
ollydbg will most probably break on some system call
when it breaks you can search the entire memory of the process
(alt+m right click search ctrl+l for repeating)for the string you entered
set an access breakpoint (hardware break point on read) on the location
if the application is not much obfuscated call stack may show you the applications code where it entered system you can also follow from there
if the application hasn't sub classed its controls setting a break point on windowproc or classproc will also get you the right context to follow your string   if the app uses directx you can set breaks at SendInput() apis or DrawText(...) apis

Find a string that I entered in ollydbg


Can I fly a quadcopter over 50m above a property I don't own according to the UK's Dronecode?

Question: I have a question about the law on flying quadcopters equipped with a camera in the UK. The dronesafe.uk website states that drones are not to be flown within 50m of any property or people that you do not have control over. Does this mean horizontally or both horizontally and vertically? Basically is it legal to fly a quadcopter above a property that I do not own as long as it is 50m or above the property?
Comment: Be aware that the Dronecode is not law.
Answer: Take a look at page 2 of the "Dronecode". The illustration makes it quite obvious that the 50 metres refers to both vertical and horizontal distance:
Comment: @Cabe 50 meters distance is for **isolated** buildings or people. In build up areas (towns, cities, campsites and crowds), you are NOT allowed to fly over, but must stay 150 metres horizontal distance away.
Comment: I know it's obvious but the diagram on the right made me have second thoughts about if i was right. The only reason i asked is because i didn't want to break the law. Thanks for clearing things up for me.


What is the voltage that an intracortical electrode is expected to receive?

Question: When a neuron fires, an action potential of about 100 mV is generated. An electrode measuring brain activity will record several hundreds neurons at a time. How much voltage an electrode directly in contact with brain tissue is expected to receive?
Answer: The Utah array is a multi-electrode array for intracortical recordings. In one of many publications on this device, the authors show some sample traces that reveal amplitudes generally between 5 and 40 microVolts. However, measured voltage will depend on the vigilance state of the brain, recording area, time on the millisecond scale, time on the macro scale (gliosis) and insertion depth and so forth.
Note that extracellular electrodes will never measure the high potentials that occur at the membrane surface as recorded through intracellular electrodes. Because of the distance of extracellular electrodes to the neuronal cell membranes, the signals are much smaller.
Reference
- Craig et al., Electroencephal clin Neurophysiol (1997); 102: 228-239


How does this implementation of full disk encryption work?

Question: I have a laptop that has Sophos Safeguard full disk encryption on it. I booted the machine into another operating system on a USB stick and attempted to read the disk from the other OS, and I verified that the disk was encrypted and I could not read it. This machine does not have a TPM chip. I do not have to enter a PIN or a passphrase or insert a USB stick when I boot it up - it loads up the operating system seamlessly. Given these facts, where is the encryption key stored and how could it be stored securely?
Comment: If the software can indeed decrypt the disk without you entering a password or putting in a "dongle", and without network connectivity (as stated in a comment below), it's pretty obvious that the whole system is crap. The software obviously stores the key somewhere on the computer (on disk), presumably in a somewhat obfuscated way -- there is no other way they could decrypt the disk (unless everybody uses the same key...). However, if _they_ can read it, anyone with access to the computer can.
Answer: From what I can find on Sophos website, it looks like the encryption keys and revelant certificates are stored on a mssql database which holds the information.

The SafeGuard Enterprise Database(s) hold all relevant data such as
  keys/certificates, information about users and computers, events and
  policy settings. The database(s) need to be accessed by the SafeGuard
  Enterprise Server and by one security officer only through the SafeGuard
  Management Center, usually the Master Security Officer. The SafeGuard
  Enterprise Database(s) can be generated and configured using a wizard
  or scripts.
  http://www.sophos.com/en-us/medialibrary/PDFs/documentation/sgn_61_ig_eng_installation.pdf?la=en
Comment: Why don't you contact Sophos support and ask them ? They are the ones who can help you, really.
Comment: Thank you for the information. I am sure that the Sophos client does communicate with a policy server over the network from time to time, however, I can still boot up the machine even if it is completely disconnected from the network. Therefore, the key must be stored locally... somewhere. I just don't know where or how. This is why I'm confused.


How to know that which requests run in sync with the browser's execution thread, and which run out of sync?

Question: From the developer tool, how can we find out which requests run in sync with the browser's execution thread, and which run out of sync in the webpage? and
To check the performance of website which requests should be included for the performance testing of the website?
Comment: We need alot more info to help you there.  It depends on the way the application is built.  I would suggest opening your browser client tool where you can pull out traffic and get an image of that attached in here as well as specify more about the application under test with reference to specific targets and what your definition for "in sync" and "out of sync" is to be sure everyone is understanding your full intent
Comment: If we take an example of google.com. Then from developer tool how can we know which are dependent requests and which are independent requests.
Answer: The approach should be the following:

Configure your HTTP Request samplers to download so called "embedded resources" from HTML pages, this will simulate real browsers behavior (1 main request to the HTML page followed by parallel requests to download images, scripts and styles). It can be done using HTTP Request Defaults configuration element.

here you can also exclude external resources to focus only on the application you are testing at the moment
Add HTTP Cache Manager to represent the browser cache as real browsers download these images, scripts and styles only once, on subsequent requests the resources are being returned from the disk cache.
If there are any dependent requests originating i.e. from AJAX calls they need to be added manually

See Web Testing with JMeter: How To Properly Handle Embedded Resources in HTML Responses article for more details.
So in general there is always one main call followed by parallel calls to embedded resources and JavaScript-driven chained calls (if any)


40 amp range into 50 amp plug

Question: I have an existing 220v 50 amp plug in my garage just bought a new 40 amp
Range, would like to plug in range in garage just till after thanksgiving
Then will replace aa cooktop with it in kitchen can I buy a cord to match the 50 amp plug and use range over thanksgiving or will it ruin range or be a safety hazard
Comment: The minimum branch circuit required for ranges 8-3/4 KW and larger is 40A. They do make a 40/50 amp outlet and plug that would work fine for your range. It will not ruin your range to be on a 50 amp breaker, it will only draw what it needs. Usually there is a maximum recommended breaker size based on the range wiring but I usually install 40/50 amp outlets with a 50 amp breaker and wiring so if a high end unit is purchased at a later time the wiring can handle the load.
Comment: Our single oven GE range (JSP31GP) has been on a 50-A breaker for 24 years, but this question sent me to the installation instructions. They say to use a 40-A breaker and No. 8 wire! This is the breaker which the builder put in 46 years ago for the original double oven electric range with integral exhaust fan. We now have a separate exhaust fan. When we replace this range I might change the breaker to whatever is specified, but may just leave it.
Answer: Using a 50A plug and receptacle is allowed on a 40A circuit because of an exception in the Electrical Code.  The exception is because 40A receptacles do not exist, or rather, are not part of the NEMA standards. (There are enough varieties of receptacle already!)
The circuit breaker must be no larger than the wiring is fit for - if the wiring is 8 AWG, the breaker must be 40A (or smaller).   If the wire is 6 AWG, the breaker may be 40 or 50 amps (or any value up to 50A).  With large circuits like this, there is only one appliance per circuit.   I am not sure whether it is legal to plug a 40A rated appliance into a circuit breakered for 50A.  I would downgrade the breaker to 40A for an extra bit of safety.
This is a good time to look at the receptacle.  If it's an old NEMA 10-50 type, it does not have a ground wire, and any problem with the neutral can electrify the chassis of the stove, a potentially lethal situation.  A ground wire can be retrofitted using any viable route back to the panel. (Grounds don't have to travel with the conductors).  Then you can upgrade the connectors to NEMA 14-50 type and change the jumper on the appliance to use a separate ground.
Answer: First -- there is no NEMA 10-40 or 14-40 plug or receptacle, only the 10-50 and the 14-50.  (We already have a zillion flavors of receptacle, so why add more?) So, the Code says to use 50A receptacles on 40A branch circuits to begin with -- this is in 210.21(B) and its associated table. (Other places in the Code also use the verbiage "the receptacle rating shall be no less than the branch circuit rating".)
Second, the breaker protects the wiring of the branch circuit -- plugging a 40A range into a 50A circuit is simply a bigger form of plugging a 1A radio into a 15A circuit, something we do all the time.  Furthermore, it is sanctioned by NEC 210.22:

210.22 Permissible Loads, Individual Branch Circuits.
  An individual branch circuit shall be permitted to supply
  any load for which it is rated, but in no case shall the load
  exceed the branch-circuit ampere rating.

Finally, do check the wiring -- 8AWG wiring goes with a 40A breaker, and 6AWG wiring with a 50A.  Furthermore, the old-style NEMA 10-50s lack a ground, instead using the neutral as ground.  This should be rectified, lest an open neutral cause the stove's chassis to go hot.  Fortunately, the NEC allows branch circuit ground wires to be retrofitted whichever way is most convenient instead of forcing them to run with the circuit wires, so running a 6AWG wire or bare armored ground cable via the most practical route back to the panel is the easiest way to do it.  Then you can put a 14-50 in and re-jumper the appliance for a separate ground.
Comment: @JimStewart You are correct that ranges and dryers need both 240 and 120V.    The dryer wiring, BTW, is 2 hots and a neutral, allowing the motor and timer to run off of 120V while the heater runs off of 240V.
Comment: I have a 3-wire connection for the dryer, but the heavy ground wire that leads to the panel is grounded to the cold water pipe for the washer and is exposed right next to the dryer. I could connect a wire from the ground terminal of the dryer to that gnd wire and not change to a 4-wire plug and cord. In the connection block of the dryer I would remove the neutral to chassis ground bond. Code violation? Someone could later disconnect that ground and the chassis would not be grounded. I could change to a 4-wire receptacle and connect a new gnd  inside the wall or outside to the nearby gnd.
Comment: @JimStewart -- post a new question with your situation, that way we can better help you :)

40 amp range into 50 amp plug


The exsistence of IBM's Deep Blue

Question: How would IBM's Deep Blue fair against modern day champions like Carlsen? Was it decommissioned after Kasparov's game?
Comment: See also http://chess.stackexchange.com/questions/5702/can-i-buy-ibm-deepblue
Answer: The match with Kasparov was very close - 3.5 - 2.5 and it is arguable that Kasparov's loss was due to psychological factors. Until Carlsen's recent disastrous tournament where he went to pieces psychologically after over stepping the time control in round one I would have said that Carlsen is psychologically stronger than Kasparov but now I'm not so sure.
Modern day players like Carlsen have closed the gap that existed between Kasparov and the rest without opening up a big gap. I want to say that Carlsen would beat Deep Blue but I suspect the truth is that it would be a close match again.
Deep Blue was dismantled and parts of it can now be seen in two different US museums - http://en.m.wikipedia.org/wiki/Deep_Blue_(chess_computer).
Answer: New generation always break the records of previous generation, It happens in every game, for example if I talk about soccer New generation has better training and strong emphasis on psychology factor. In addition Garry Kasparov doesn't have that kind of concentration  Carlson have , as he has to take care Russian Politics and his Professional Chess academy https://en.wikipedia.org/wiki/Professional_Chess_Association. 3rd factor I think is age with age function of brain deteriorate at-least I have learn it from my brain. These factor may have played have some role. But I don't want to take away brilliance of Magnus Carlson. He is simply awesome and can beat even faster computers than Deep Blue.
Answer: If you're going to let chess players improve (substituting Carlsen of today for Kasparov of two decades ago) before this theoretical match, you'll have to let the computer's hardware and software improve, as well. Given the overall rate of improvement in top Grandmaster skill vs that of computer hardware and software over the last twenty years (hardware improvements alone would allow DB a calculation speed gain of roughly 1000 times, for example -- remember in 1996 the typical desktop CPU was a single-core 75Mhz Pentium) I suspect a modern version of Deep Blue could probably give Carlsen pawn odds and still not lose a game.
Answer: It will fail miserably against Carlsen since it was designed specially for playing against Kasparov.
It was decommissioned since it was a single purpose machine and had achieved the designated goal.
The hardware was sold to a Sheikh in Middle East.

The exsistence of IBM’s Deep Blue


Lost and in need of guidance

Question: I live in Dickinson, North Dakota USA and I am wanting to follow Buddha but have no one to teach me or to ask questions to. I has wondering if there is anyway to get in to contact with a Theravada Buddhist Monk to help guide me down my path? I have checked my local library and online for books but nothing comes up helpful.
Comment: Hi and welcome to Buddhism SE.
Answer: If you are looking for a place to ask questions about Buddhism (or to read through the many questions that have already been answered); this is a good place to do that. Our format is that anyone who believes they have the answer to a question may submit that answer for your consideration. So questions will be answered by both monastic and lay people of various traditions. If you are looking for an answer from a specific tradition, simple tag your question as you've done above.
Among the many questions that have already been answered on this site are community wikis such as this list of introductory books. Another online resource is this video wiki created by a Buddhism.SE moderator and frequent contributor, Venerable Yuttadhammo. Hundreds of questions and answers in video form are included here.
For local resources here is a short list of Theravada centers in your area.
Once you've had a chance to check these resources, if you have additional questions, please feel free to submit them! Our New User Welcome gives some tips on how to best use this site. Best wishes!
Answer: The Theravada spirit has always been the emphasis on the "teaching" over a teacher. A common analogy is that the teaching is like the US Constitution while the teachers are like the US presidents. Presidents come and go, and might say different things at different times, but the Constitution is always there, consistent, and timeless. There're many great web sites with detailed info. about the Theravada teaching, the most popular are: accesstoinsight.org, suttacentral.net, budsas.org/ebud/ebidx.htm, palikanon.com. The introductory section of accesstoinsight.org is particularly helpful and I'd strongly recommend you check it out if you haven't. Good luck..
Comment: +1 for the constitution-simile. Timelessness in the dhamma.
Answer: Unless there's someone who's a very good teacher at a local temple, meeting with a monk regularly may not be the easiest or best way to go about it.
My suggestion is to find one or more good teachers that you can relate to, wherever they are in the world, and take a retreat with them. This will teach you enough to practice on your own. A local practice centre can be found just about anywhere, and if you develop ties with them, they will be a great motivation to practice.
Well known Theravada Retreat Centres in the USA:

Abhayagiri Forest Monastery, California
Bhavana Society, West Virginia
Vipassana Meditation Center, U Bha Khin/Goenka

Other Resources:

Practice groups in North Dakota
Other Dhamma centres and groups in USA
Theravadan Websites to see

Some teachers and books have a study group or practice community that meets regularly online. For example,

Mastering the Core Teachings of the Buddha
Dharma Overground
Answer: "What the Buddha Taught" is one of the best out there to get started. http://www.amazon.com/What-Buddha-Taught-Expanded-Dhammapada/dp/0802130313
Free PDF seems to be available at http://www.dhammaweb.net/books/Dr_Walpola_Rahula_What_the_Buddha_Taught.pdf
Answer: Bhante Gunaratana's "Mindfulness in Plain English" is a good place to start in getting a meditation practice going and on track. He is abbot at the Bhavana Society forest monastery in West Virginia and at age 88 still leads retreats.
Answer: In addition, I would like to recommend you to follow Ven. Ajahn Brahmawamso's YouTube channel and read his publications. It is an easy method for new converts to understand the basic concepts in buddhism in an easy way.
Visit Ven.Ajahn Brahmawamso's YouTube channel!
Answer: Books are the way to go. There is simply no substitute.
I recommend Mastering the Core Teachings of the Buddha to develop a pragmatic Theravadin perspective with an "American" bite to it. It also educates you on how to evaluate other traditions.

Lost and in need of guidance


Why won't hot water come after timer of recirculating pump is off?

Question: About a year ago, we had a Grundfos recirculating pump installed. We use a timer on it for morning showers. Recently, after the timer goes off, and someone needs to use the master bath shower later, no hot water comes even after waiting quite a while.  There is hot water in the other bathrooms and kitchen sink. Any suggestions about why this is happening?
Thank you.
Answer: Probably a failed/stuck/jammed check valve, if this was the typical (maketh me shudder) retrofit installation where the hot water recirculation line is the cold water line. That makes the proper operation utterly dependent on the check valve, or the cold water line can happily backfeed into the hot water.
The less-shudder-inducing system I prefer is a dedicated recirculation return line, but that can be hard to retrofit (and can have the same problem, if a bit less, since it normally returns to the cold side of the hot water heater.)


What character names can I use for new heroes that are not copyrighted?

Question: I need to know if I can only use names that are not taken at all (very frustrating), or if there is a way to use names I really want to use and it be okay.
Comment: Hi, and welcome to Writing.SE.  Please take time to tour the page when you can.  As for your post, this may be marked as a duplicate question, and you may be able to find your answer here: https://writing.stackexchange.com/questions/4963/is-it-legal-to-write-about-trademarked-material-and-use-the-terms
Comment: Welcome to Writing.SE *Adam*! If you have a moment please take the [tour] and visit the [help] to learn more about the site. Have fun!
Comment: Hero like superhero? Or the protagonist of the story?
Answer: A name cannot be copyrighted at all, a name can only be registered as a trademark.
If the name is not trademarked, you may use it. If it is, you mustn't.
You can search for trademarks here: http://tess2.uspto.gov/
Answer: It may depend on the context of your story and the background of your hero. If your hero did not choose a name, the city that saved may have given it to him, so his name may depend on his appearance, his actions, his behavior, what he represents for the city, or his powers if he has any. If your hero chose his name, it may depend mainly in the Backstory of your hero:

The place/Language where he came from can influence in the chosen name. If your hero speaks another language, his name may mean something in his native language.
The meaning of the name in the hero's life, I will give you an example of this: In the manga of "Boku no hero academia", the main character hero name is "Deku" that means Useless in japanese, but then another charanters hives another meaning to his name

Ochaco finds the nickname inspiring and says that "Deku" gives off a feeling of "I can do it" (頑張る でく?), because of its similarity to the word meaning "to be able to do" (できる?), pronounced "dekiru".

Tribute to another Hero: The hero may take its name from another hero and modify for its custom.

There you have some infuences for your hero name and you can consider them for picking a name for him/her, I hope this helps for your story.


Where are costs for weapons listed in the Beginner Box?

Question: Just got the box and are we are making characters and have gotten to equipment, the weapons have no costs in the book (unlike equipment and armor). Does that mean the character should just pick their own weapons freely (1 melee and 1 ranged) when starting?
Answer: It's actually written right in the book, but unlike equipment and armor which has it in a big font on Orange background in the upper right corner, weapon cost is in a small black font in the lower left corner along with the other weapon stats
Comment: Adding where in the basic set you found the costs would make for a much better answer.
Comment: To expand on Weaveworker's comment: the question posed (by you) was "*where* are costs...?" It's absolutely fine to answer your own questions, but you should actually answer the question when you do so. So go ahead and put in a few lines with the solution to the problem you had. That way, when someone else has it they can find the Q&A that wasn't here when you came looking.
Comment: I'd also suggest adding a page reference here.  The more detail you include, the better your answer will be.


Simple Scorecard Conditional Formatting

Question: I simply want to create a scoresheet comparing scores to par.  If less than par then a red number, if more than par then highlight red, if equal to par then highlight green.  Here is what I'm trying to accomplish:
Par = cell B5 thru J5 and L5 thru T5
Score = if B6 thru J6 and L6 thru T6 are lower than par, the number is red; if equal to par then highlight green; if greater than par then highlight red.
I've tried it numerous times and it doesn't work.  Can someone assist, please?
Comment: share a copy of your sheet
Answer: red color:
=IF(ARRAYFORMULA(IF(LEN(B5:T6),
 IF(B5:T5 > B6:T6, 2,
 IF(B5:T5 < B6:T6, 2, )), ))=2, 1)
green color:
=IF(ARRAYFORMULA(IF(LEN(B$5:T6),
 IF(B$5:T$5 = B$6:T$6, 1, ), ))=1, 1)

Simple Scorecard Conditional Formatting


Meaning of the line "I'm not a psychopath, I'm a highly functioning sociopath"

Question: What does Sherlock mean exactly when he says "I'm not a psychopath, I'm a highly functioning sociopath"? What is the meaning of this line ?
Comment: It's pretty evident from the statement. He is saying that he is not crazy but rather a very intelligent human being who lacks a sense of moral responsibility or social conscience.
Comment: __[Stop Calling Sherlock a Sociopath! Thanks, a Psychologist.](http://io9.com/5933869/stop-calling-sherlock-a-sociopath-thanks-a-psychologist):__ _"... psychopaths and sociopaths are the exact same thing. There is no difference. Whatsoever. Psychopathy is the term used in modern clinical literature, while sociopathy is a term that was coined by [G. E. Partridge](http://en.wikipedia.org/wiki/George_E._Partridge) in 1930 to emphasize the disorder's social transgressions and that has since fallen out of use."_
Comment: @invalid_id: I dont think Sherlock meant for it to be a joke. There is a line missing from the question. He says "I'm not a psychopath, I'm a highly functioning sociopath. Do your research." Sherlock obviously believes there is a difference.
Comment: This is absurd.  This is just **dry humour**.  It doesn't matter whether there is a difference between these two things or not -- he does not believe he's either one anyway.  It's a J O K E.  Humour.  Part of the humour in dry wit is the implication that it will be mistakenly taken seriously, and it is a little mean in that sense -- the teller does not care whether you take him seriously or not, but that doesn't make him a sociopath, lol.  Note in this specific context, it does't matter who takes it seriously or not.  People who don't trust him still won't, and people who do still will.
Comment: Why do I have the feeling that 99% of the answerer here doesn't have the qualifications necessary to answer this question properly. You may have a better answer at [cogsci.se].
Comment: This might be the key:
"It is believed that psychopathy is the result of "nature" (genetics) while sociopathy is the result of "nurture" (environment)."
I'm curious for the answer. The latter might mean he had a trauma or something similar.
Answer: While the medical use of the terms are interchangeable, most people in common language use them differently:

psychopath - a berserker who has gone crazy and is running around killing people, smashing stuff etc. Think "psychotic" for the mental image
sociopath - someone who really doesn't care about society's norms, such as not killing or hurting other people, and acts only for their own gain

(The "high functioning" part is a red herring, sociopaths function really well and run companies etc. You usually see "High Functioning" paired with Aspergers or Autism, not Sociopath. But whatever.)
Sherlock isn't really a sociopath since he helps people all the time, while pretending he's only doing it because he enjoys the puzzle or the game. In fact in this very episode, his motivation for the act that follows the line,

 shooting the bad guy to protect Mrs Watson's secret which is only in the bad guy's head

is to help another person. That said, the line is "in character" since he likes to pretend he doesn't care, and he is able to do things without a qualm that most of us would not do.
Comment: in other words, a slightly more sophisticated version of "I'm not crazy; my mother had me tested!"
Comment: The line is intended to be humorous (for the audience, not as an intentional joke by Sherlock.)  I think part of the joke was that "high functioning" part was to imply that he had been actually diagnosed, by either a psychiatrist or himself, as a for real "high functioning sociopath," whereas the person asking the original question was being at least somewhat hyperbolic, and did not expect Sherlock to actually be a diagnosed psychopath or a sociopath.  In other words, "high functioning" was not intended by the writers to be a red herring, in my opinion.
Comment: @Kai I agree if you mean the "highly functioning" part is intended as a tell tail that **this is a joke**.
Answer: Knowing the original stories and many adaptations, I'm 99% sure, that Sherlock is a high functioning Asperger's, he's NOT a sociopath- it's only the BBC series' writer's fantasy.
'Sociopath' and 'psychopath' are the SAME thing, only different areas of medical and psychological research and different countries used different terms.
Quoted from here
Comment: I've always made the distinction that a sociopathy is a lack of empathy. Whereas a psychopath is violent, delusional, no control, etc. However, Google/Wiki doesn't seem to make any distinction. So you may be right. However if you told me I had to go through one of two rooms, one with a psychopath and one with a sociopath, I'm taking option two.
Comment: A psychopath is not necessarily delusional.  You're confusing a psychopath with a psychotic.
Comment: Correct me if I'm wrong, but I think a psychopath is someone who can't control how they act around people, so from another persons point of view, it seems as if they are unstable, when they are really just confused.
Comment: Ya. This is wrong. The prefixes "socio" and "psycho" imply different things. Sociopaths don't follow societal norms because of environmental factors, whereas psychopaths are affected by hereditary/genetic issues. -1
Comment: Dr Bonn disagrees with you - http://www.psychologytoday.com/blog/wicked-deeds/201401/how-tell-sociopath-psychopath
Comment: This still doesn't seem to provide an answer to the actual question, apart from saying *"the writers were wrong according to top-notch psychological theory"*. If all you wanted to say is that the whole question is completely moot because that line isn't based on reality and thus doesn't mean *anything* at all, you might want to clarify that in your answer. Otherwise a comment would have sufficed for this.
Comment: The original stories and other adaptations seem irrelevant as this is a quote *only* from the new **Sherlock**.
Answer: While I have to defer to the many posters who have greater knowledge than I do of how the terms should be used, I think these are the meanings intended, which would make the distinction Sherlock draws make some sense:
A sociopath is someone who lacks empathy.  They are aware of their own emotions, but tend to be oblivious to what others show themselves to be feeling, or would obviously (to a non-sociopath) be feeling.   (For an example, see "A Study in Scarlet", where Sherlock protests that surely, a woman wouldn't still be upset about a child of hers who died years ago.  When he says it, he can deduce immediately from the reactions of the others that what he's said is not only wrong, but grotesquely wrong from the perspective of those who do have empathy - but it's a deduction, not because he suddenly understands the bond between a mother and child.)  A sociopath who is "high-functioning", as Sherlock claims to be, is presumably one who can navigate acceptably well through social situations, by using deduction as a substitute for the ability to imagine themselves in another's shoes.
A psychopath, by contrast with a sociopath, doesn't even want to navigate acceptably through social situations - if he says things that are grotesque and horrifying to other people, what does he care?  It doesn't make him feel bad, so why would it matter to him?  If he has to balance between "this would give me a good chuckle" and "this would leave the other person traumatized, crippled, or even dead" - well, it's a no-brainer, isn't it?  It would bring him amusement, and he won't feel anything seeing the other person's pain - heck, maybe he even gets fun from witnessing their pain.
When Sherlock snaps that he is a high-functioning sociopath, not a psychopath, he's doing so in response to the female cop's insinuation that someday he'll switch from solving crimes to committing them.  There are many possible explanations for why he might be so annoyed by the suggestion.  A strong possibility, however, is that he's irked that she misunderstands his tastes so badly.  To suggest that he is a psychopath suggests that he's that easily entertained.
Answer: Again, with apologies to the more learned in this field, I think that for Sherlock, the difference is firmly established in human bonds. Sherlock has an adversarial relationship with Mycroft who spent most of their childhood either calling Sherlock stupid or tormenting him with stories of the north wind. Sherlock's childhood love, which again Mycroft taunts him about was for his dog, Redbeard. But at least Sherlock had that.  Mycroft, like Moriarty,  has no human contacts based on love and affection.  As Moriarty proved, Sherlock had at least 3 that even a true psychopath could see: Watson, Mrs. Hudson,  and Lestrade. His error according to Sherlock, was discounting Molly.  In season 3, almost from the very beginning Mary is added to the list and John's future child also as seen in his last vow.
For Sherlock,  being a highly functioning sociopath is important because it allows him to love and be loved without limiting him to the role of hero. He is and always has been an antihero,  as Mycroft said, he has the mind to be a scientist or philosopher, but chose to be a private detective. ..but originally he wanted to be a pirate.
Answer: Incorrect.  Psychopaths are higher functioning typically than a sociopath and able to keep track of their lies. This is usually because they use the same ones over and over again. Those that change their story do so purposely for amusement and not because they can't keep track.  A psychopath lies for a reason even if it's a bad one.  A disorganized psychopath will have periods of organization, but a sociopath will always struggle to keep ahead of their lies because they do it constantly.  A psychopath usually picks and chooses, priding himself on the fact that he's able to deceive people with the truth.  A sociopath feels more anxiety about lying because they're unable to keep track. Their explanations become disorganized once caught,  but a psychopath is right on top of that and will turn it around so that the evidence of a lie no longer appears to be evidence.  A psychopath OR sociopath can love, but usually don't. A psychopath can turn it on and off, but a sociopath cannot turn actual feelings on or off.  They're there or they're not. This has been proven through scientific research and testing on the brains of subjects to prove love centers light up. A psychopath may become despondent at the loss of a pet, but a sociopath feels the loss of attention only and has a temper tantrum if anything. Both behaviors or diagnoses can also be present in the same subject. Psychopaths have also been known to lie to protect another's feelings at times while a sociopath is not that self aware or the effect they have.
So,  the line from the series tries to delineate between those that can be saved/productive citizens and those that cannot and simply does so directly. The line is simply not that clear cut.
Comment: let's assume that all of this is accurate and correct. How does it answer the question about the meaning of Sherlock's line in any way?
Answer: It's a lie, for one thing. But the defining line between psychopathy and sociopathy is both of them lack emotions and empathy, but socios recognize they have little to gain by breaking the law and remain mostly morally sound despite not caring, while psychopaths revel in going against societal norms and evoking strong emotions in others like fear and rage, which is why murderers are call psychos.


On an HP nc6400 laptop the mute light on the mute button stays on?

Question: On an HP nc6400 laptop the mute light on the mute button stays on even when Ubuntu is not on mute, this only is happening after I upgraded to Ubuntu 11.04, it worked fine in 10.10.
Even though the mute light stays on, if you start playing a piece of music or a sound it will play and the mute light will go off for the duration of the sound and then come back on immediately after the sound has finished. Pressing the mute button on and off only turns the light off for less than a second, it will immediately come back on again. The mute light will go off while I am adjusting the volume but will come back on no matter where I put the volume bar. While it doesn't affect usability it is rather annoying.
Answer: Try this: open a terminal and enter the following command:
gksu gedit /etc/modprobe.d/alsa-base.conf

Then add the following line at the end of the file and save it:
amixer set IEC958 off

The command above is to switch it off.
Now just reboot your system.
Source: LED And Low Sound Issue In Macbook Running Ubuntu 11.04
Comment: No, it's still there :(


"Swap file xxx already exists" when editing apache configuration file in vim?

Question: Using vim I keep getting a message saying "Swap file xxx already exists" when I'm editing an apache config.  However, I don't see it in the working directory on in tmp.  How do I delete this?
Answer: Vim swap files are normally hidden (Unix hidden files begin with a .). In order to view hidden files as well as regular ones, you need to ls -A (mnemonic: A for All). That should show you whether a swap file is there or not.
Answer: This happens only when the file you were trying to edit is not saved completely on to the disk. Scenarios are :

You shut down your system improperly, when a file is still open in vi/vim.
when your file is being accessed concurrently via different/same
    consoles in vi.

vi/vim creates a .swp file whenever a file is opened in vi/vim. Everytime a file is opened in vi/vim, vi/vim checks for this file and if found this warning pops up
This is can be avoided in two ways

one by deleting the .swp file which is named as

"path/of/the/file/you/were/editing/.your_file_name.swp"

you can also opt for recover mode of vi/vim when opening the file
and pressing recovery option .

I am just talking about the first scenario and it is safe for only that scenario. Scenario second is the different case.
Comment: If there were unsaved changes, you can recover them using `vi -r` (or `vim -r` if you prefer).  I usually write the recovered file to a temporary file and `diff` it against the main file.  (I don't quite trust the recovery not to lose information.)
Answer: In the message, you should see the full path to the file. You can rm it by copy-pasting the path as follows:
rm -f /path/to/the/file

Answer: If the file you're editing is called httpd.conf then the swap file will be called .httpd.conf.swp. It is hidden unless you add -a to your ls arguments.
ls -a /etc/httpd/conf/

Answer: To remove the swap file in Linux use this command
rm .filename.swp


Finding output with unique witness in matrix multiplication

Question: Consider two square matrices $A(x,y)$ and $B(y,z)$ of dimensions $N \times N$ containing boolean entries. Consider the output product matrix $C(x,z)$ where $C = AB$ (not boolean matrix multiplication but the entries store the count of how many $y$ generate a given output entry). My goal is to find only the output entries in $C$ which are generated by exactly one value of $y$ (i.e. a unique witness). In other words, I want to find all $(i,j)$ such that $C(i,j) = 1$. Clearly, I can simply perform the matrix multiplication and iterate over $C$ to identify the output with unique witnesses but can we do better? Is this problem as hard as matrix multiplication itself? Are there are any known reductions that consider the problem of finding output that is generated by a unique $y$ value? I am interested in deterministic algorithms but even something probabilistic may be insightful.
Answer: You can reduce Boolean matrix multiplication (BMM) to this problem. (BMM is matrix multiplication over the OR/AND semiring with 0 and 1.) Imagine adding one more column to the first matrix A and one more row to the first matrix B, both of which are all-ones. If the BMM of A and B had a 0 in an entry, your new product over the integers will have 1, and if the BMM had a 1 in an entry, your new product over the integers will have at least a 2. Thus determining these "exactly one" entries is at least as hard as BMM.
Whether or not BMM can be solved faster than matrix multiplication over a ring or field is a major open problem.
Comment: My last statement says nothing about "combinatorial" algorithms. There is another open problem about combinatorial BMM but is not really well-defined, compared to the problem I stated. Again, stated slightly differently: it is open whether BMM can be solved in o(n^omega) time where omega is the matrix multiplication exponent (for arbitrary rings, or for fields)
Comment: Complexity nerdom https://starwars.fandom.com/wiki/Dark_Lord_of_the_Sith
Comment: Ah ok I get your comment now -- maybe BMM can be done even faster than $O(N^\omega)$ given that we have boolean entries (which intuitively should be "easier" to deal with). Thanks @ryan-williams -- King of fine-grained complexity, protector of the SETH.
Comment: You're welcome. Your titles made me LOL! (Funny that I would be chosen as "protector of the SETH"...)
Comment: Very cool! The problem is BMM-hard is more than enough for my purpose. For your last statement, you mean BMM can be solved faster than some "combinatorial" matrix multiplication algorithm over a ring or field right? We can solve general matrix multiplication in $O(N^\omega)$ time which can be used for BMM but we don't know if we can do BMM in subcubic time, which is the best combinatorial matrix multiplication algorithm (modulo log factors) we know of (right?).
Comment: Actually @RyanWilliams seeks to destroy SETHdom afaik.
Comment: @1.. Fate loves irony :-)


reinstalled multibit wallet

Question: I had to remove a copy of multibit wallet from my system & after multiple times of trying to get it to work on my 64 bit system I can now open multibit wallet. I guess when I removed the program that the wallet .dat files were removed as well but I do have the wallet addresses that were removed. Is it possible to retrieve the missing data? Can I just send my bitcoin to another wallet or do I have to have the .dat file in order to accomplish this? Hopefully I have not caused all my bitcoin to go away permanantly. Any advice on this subject will be totally appreciated big time.
Answer: According to MultiBit's Getting Started, the wallet file of MultiBit seems to be named multibit.wallet, not wallet.dat. You might want to try searching for that instead.
Sorry to break the bad news, but the addresses aren't sufficient to regain control of the bitcoins. If that were the case, anyone that knew your address could grab your coins, and addresses are public information which would make for a very insecure system.
Therefore, you need your private keys in order to transfer your bitcoins.

reinstalled multibit wallet