Is it possible to have a Society to evolve into a industrial age society without discovering gunpowder

Question: I want my world to be set in early to mid Industrial Age but for various reasons that I won't go into here I don't want there to be any gunpowder based weapons.  Is it possible for a society to advance to the Industrial Age without ever discovering gunpowder?
Comment: Do you mean gunpowder specifically, or any firearm that operates by using a chemical reaction to produce gas pressure to force a projectile down a tube?
Comment: @TonyEnnis Or even without a chemical reaction- lethal airguns date all the way back to the Renaissance as hunting weapons, and were even briefly used militarily in the late 1700s.
Comment: well considering how important discoveries of chemistry was to industrialization,  I doubt it. Chemistry let to consistent quality of production in metals, ceramics and oils which made industrialization possible.
Comment: It's also worth exploring that we knew about gun powder long before we knew about guns. We also knew about gasoline long before we knew about internal combustion engines. There might be something laying around in your room right now that could revolutionize our lives but none of us know what to do with it yet.
Comment: As a side note, the Romans were starting to develop technology such as mechanized reapers, water powered sawmills, hydraulic mining and an early steam engine.  Then that whole Dark Ages thing happened...
Comment: @Catgut they were also used in American colonial times (Lewis and Clark expedition) and were indeed lethal.  But that's not "gunpowder". Perhaps the OP really means "firearms that are not completely powered by human muscles".
Answer: It is certainly possible. Mechanisation is what defines the industrial age, and mechanisation is entirely separate to gunpowder. The first thing that was mechanised was agriculture with things like reaper-binders. This freed enough population from working on the land to be employed in factories. The next was the textile industry which was relatively simple to automate and from there it snowballed.
There is however a major caveat to all of this. As your industrial revolution progresses more and more chemistry is going to be required for things like metallurgy (which is fairly important if you want metal good enough for things like steam engines.) The further into an industrial revolution the less and less likely that a simple chemical mixture like gunpowder would remain undiscovered.
Comment: @Static I would guess that gunpowder is not a requirement per se, but rather an accelerant. To suppose that an industrial revolution wouldn't occur due to a single missing piece is unlikely. At the most I would suppose it would merely slow it down, not halt it.
Comment: @WilliamC. High explosives in general were quite important, though - otherwise you'll never get cheap iron. They made mining much faster - and could be used instead of gunpowder in weapons. It's hard to guess how much of an impact any of the "critical" technologies would make - all we see is how one thing led to another in a chain reaction that produced the massive productivity boosts in pretty much everything humans do.
Comment: @Raditz_35 For mid to late Industrial revolution (1790-1820 ish) I'd agree with you, the probability of gunpowder being discovered (and need for it) is just too high. But early to mid (1760-1790 ish) which is transitioning to machine labour, could be done. Although i'd expect the invention of gunpowder fairly soon.
Comment: Mechanisation was based on metallurgy and boring techniques developed for use in cannons and firearms. It is not a clearly separate development.
Comment: I disagree a bit here. You describe the rise of the manufactories and so on, not that of industrialization. I also think there is just no way we could have a "mid industrial age" without discovering gun powder, sorry - see my answer. In fact, gunpowder was one of the main driving forces behind constructing advanced machinery
Comment: Very well, that sounds reasonable enough
Answer: It's quite hard to say. Drilling and blasting has been key to mining and quarrying since 1627 and because mining is key to industrialisation it's certainly going to have an effect.
Whether it would prevent a culture from industrialising or not depends on how well that culture manages to bypass explosive mining, which is still standard practice, and develop mechanical mining processes to replace it.
Comment: The discovery of something like liquid nitroglycerin allows for major blasting, but it is not easily translated into a firearm.
Comment: @Amadeus It's not easily translated into a safe explosive either - it became a lot more popular when dynamite was developed. And it is used in weapons even today (nitrocellulose, cordite and such). It's possible it would only be used in mining, but it's not very likely. At the very least, it would be used in cannons - it's not clear if the OP wants to exclude those or not.
Comment: I don't think it's valid to assume that "no gunpowder" means "no explosives of any kind".
Comment: This is quite plausible. The key here is never finding out that the gunpower mix can be made safe enough for field handling; probably due to not trying after discovering nitroglycerine is too hard to stabilize.
Answer: Maybe it is not nice to say, but warfare and weapon research is often the main driver for techical development.
Just to give an example in your reference era, thermodynamic started when somebody noticed that drilling a cannon generates heat and then started investigating this.
If you remove gunpowder you remove some if not all of the need for better metals, than can withstand the explosion without blowing off (too often) the face of the gunman.
Also, no gunpowder would have made the expansion of Western nations into America, Asia and Australia more difficult if not impossible, due to the limited logistic capabilities which could not sustain a long term engagement far away from homeland. This would in turn have reduced the growth of those nations and, again, the need for better technologies.
Therefore my answer is no, without gunpowder it wouldn't be possible for a society to develop until industrial revolution.
Answer: There are two problems one will have to solve, to allow industrial technology but no gunpowder: firstly, how could an industrial society not discover gunpowder on its own? and secondly, could an industrial revolution (or a slower transition towards industrialization) happen without gunpowder?
problem 1: Not allowing gunpowder development
(edit) I understand that the main point of the question is to examine the effects on the industrial society, and not explaining why gunpowder couldn't be developed, but I do still consider this relevant since the reason for gunpowder not to be developed still would affect the society.
Rare resources
The first thing one could do to make gunpowder development impossible would simply be to claim that the components of gunpowder (coal, saltpeter ($KNO_3$), and sulfur) are very rare on the planet on which this civilization exists; this explanation would, however, have some problems since the chemical elements involved in making gunpowder are essential building blocks of living organisms, because one would have to come up with an explanation for how this planet ended up without some of these elements, and because a scarcity of coal would make industrialization quite hard.
Not even to mention that the chemists of your society still could invent other explosives, which doesn't include the rare components.
If for instance sulfur is rare, you should still be able to make nitroglycerin and TNT, and if it is nitrogen which is rare, oil (both vegetable oil and from the underground) could be used to make firebombs.
Religion/culture
Maybe the dominant culture or religion could ban explosive weapons, perhaps because they consider it to be demonic, or out of fear that the population would use this weapon against the ruling class.
There are an obvious problem with this: if one civilization bans gunpowder, it would easily be overtaken by another one, which doesn't. Using this explanation might, therefore, require the assumption that one civilization long before gunpowder was discovered, became the dominant power on the planet – If you want this to be set on earth, you could for instance claim that Alexander the Greats empire, the Persian empire, Rome, Carthage or one other ancient power came to dominate the world.
This dominant civilization would not be threatened by any other power in the world, in would therefore not need powerful weapons such as gunpowder for military purpose, and with the influence that comes with being a superpower, this dominant empire might be able to force any still independent nations to also obey their gunpowder-ban.
The superpower could then go on to eventually (possibly much later than if they had had gunpowder, and as pointed out in a comment, maybe not as a revolution but rather a slow transition) invent industrial technology on its own, and even if the superpower at some point should collapse, leading to the end of the gunpowder-ban, it would still take a while before anybody developed effective gunpowder weapons.
Problem 2: industrialization without gunpowder
Something many people have pointed out is that gunpowder has been used in mining for a very long time, and one could therefore validly have doubt to if a society without use explosives could mine enough resources to fuel an industrial society: But it is actually possible to do explosive mining without any explosive chemicals. The Roman empire did, for instance, use the Ruina Montium technique, in which they would lead a lot of water into a mountain very quickly, causing it to explode from the pressure.
I do of course not know if Ruina Montium alone could substitute explosives in mining, but at least the technique shows what an already advanced civilization can do without gunpowder.
Conclusion
In conclusion, I can neither say yes nor no, to the question: »Is it possible to have a Society to evolve into an industrial age society without discovering gunpowder?«. I have tried to outline some assumptions one could make, but I am not even convinced myself that they would be enough to achieve what you want, but even if it is possible I find it quite unlikely that an industrial society would not have gunpowder
Disclaimer (Edit)
I have only now noticed that another answer posted about the time when I started writing this answer contains the same suggestions for explanations as to why gunpowder couldn't be developed, this answer was however written completely independent from that other answer, and i believe it looks at thing from a slightly different angle, but if this answer is to similar and ought to be removed, please write that in the comments.
Comment: One does not strictly require an industrial revolution to industrialise, one could make the transition at a slower pace as more resources become available due to their production processes improving.
Comment: If you have powerful enough pope, then he can ban all guns. That basically what have happened in Japan in Edo period.
Comment: The Christianity (one of major religions) says that it is not nice to kill people, but many people ignore that. Why would the people in this world be different?
Answer: The answer is not really.
Here is the thing: Industrialization demands some kind of advanced chemistry. And in chemistry, you end up with explosives very, very quickly and straight forward. It's like asking if humans as a species could learn swimming without discovering fish - they are right there in front of you. There is just no way that we could've had anything close to our industrialization without discovering any explosives.
However
a) If there is little war, explosives might have not ended up on the battle field
b) If you would change certain aspects, making the industrialization "more primitive" - look, this needs to be a new question because this post would go on for pages, also please do some research yourself if you end up asking that question - if you drop all the things one can only do without chemical knowledge - you might reach your goal
Answer: If I understood the question correctly, No and Yes.
No, it is extremely unlikely for an industrial civilization to not know and use gunpowder.
It is a simple mixture of three fairly common and easily accessible substances. It is unlikely that discovery of gunpowder could be prevented by its components being scarce. It is also unlikely that a civilization capable of industrialization would fail to have the necessary chemistry and notice the effect saltpetre has on burning. Or fail to use explosives for mining.
Yes, it is possible for them to never use the gunpowder for guns. Making it, I guess, blasting powder instead. Or black powder. Or fire powder.
There is a direct link from discovering black powder to fireworks and low explosives, but guns actually require an extra step IMHO. Your people need to want siege weapons capable of breaking walls. If your civilization doesn't have fortifications it doesn't need siege weapons. If it doesn't need siege weapons, it will have no need for cannons. If it doesn't have cannons, it won't downscale them to guns. No airguns either.
Having fortifications and being industrialized do not seem to be connected in any way as far as I can tell. Thus there should be no reason not to have an industrialized civilization without fortifications.
Of course, the history of such civilization would be quite different from ours. How different is really a separate question, but I think your world would need to be dominated by strong and stable central governments capable of suppressing rebellions and unrest without needing fortifications to protect themselves. A government that has no use for fortifications would naturally ban anyone else from having any. And really, fortifications are too expensive to build and upkeep unless you actually need them.
Additionally, you'd need the government to not need to fear external threats. Some empires did actually reach this level of power for a period of time. There are several scenarios for this. You can have a single superior empire that suppresses "serious" warfare in its entire area of influence. You could have a diplomatic system between states that suppresses warfare. Either in general or merely siege warfare. Siege warfare makes wars longer and more expensive, so people could simply agree not to build fortifications if conditions are right. Such agreement would probably only last until the next major war, but it would suppress development of siege weapons. And the political system could be stable enough to prevent major wars.
Answer: Yet another alternative is to have a weapon more effective than primitive guns. Remember the first guns were muzzle loaded balls with a packet of gunpowder, the barrels were not rifled to create spin so the guns were wildly inaccurate. The parts were not interchangeable, either, a broken gun meant making a new part by hand. Plus they could literally blind and deafen the shooter!
So the 'alternative history' could be to advance industrialization well before the discovery of gunpowder.
IRL, the Viking's had access to crucible steel 1200 years ago; we see it in some of their swords (Ulfbhert, see http://www.pbs.org/wgbh/nova/ancient/secrets-viking-sword.html, also http://www.dailymail.co.uk/sciencetech/article-2878512/The-mystery-magical-superstrong-Viking-sword-Researchers-close-supermonks-believed-forged-weapons.html). This is steel as good and hard as modern steel, and available hundreds of years before the first written formula for gunpowder.
So, alternate history wise; suppose instead of just making swords with it, it was forged into machinery, and the magicians that made the crucible steel figured out how to make some of Archimedes weapons, too: repeating crossbows, lathes with diamond tips making fine machinery, spring steel that let archers fire accurately for hundreds of yards: Far further and more deadly than the best early blunderbusses. Suppose they fired needles, filled with lethal poison, and could actually be hand held like pistols, but with a hundred rounds instead of 6 of those big bulky bullets.
Our firearms have slowly evolved to be accurate and lethal at a distance, but that is for the same reason we have the QWERTY keyboard: It came first, was widely adopted, and became the awkward norm. If industrialization starts 300 years before we discovered gunpowder circa 1100 AD, because for some cultural quirk everybody knows how to make good steel, and some Archimedes or Da Vinci type figure of the time could make kinetic weapons powered by spring steel that made early gun shooters look like idiots playing with dynamite for no good reason; the bullets did not travel as far or as accurately as their steel darts: Say a marksman with a steel dart could hit the bullseye three times in 8 seconds at 50 yards, while a blunderbuss takes two minutes to load one shot and would be lucky to hit the target at all!
Modern steel, the discovery of fine cutting and grinding with diamonds, the invention of standardized parts. Metallurgy of our many kinds of steel would be obvious; the super hard alloys for scalpel sharp edges can happen.
On top of all that, industrial production of modern steel would help with the exploitation of other kinds of explosive fuels: Natural gas, gasoline and internal combustion engines, nitroglycerin. Even electrical discoveries are plausibly fuelled by fine metallurgical advances and refinement of metals and experiments with alloys.
Instead of gunpowder, magnetic rail guns.
The writing trick is just that something else got there first by a few centuries. It was evolved and refined by hundreds of little inventions and improvements, it was widely accepted in the culture, and the headstart was just too much for gunpowder to overcome: People were accustomed to "charging" their guns with machinery and/or horses winding thousands of pounds of energy into reliable heavy steel springs: Their guns were whisper silent, deadly, accurate, safe, carried dozens of projectiles and left no plume of smoke identifying the location of the shooter! Which made the first black-powder guns look like, to them, cavemen throwing rocks! It isn't that black powder and other such explosives were never discovered, just that the black powder gun was stillborn, a loud, smelly, inaccurate novelty, handmade by a few crackpots, that nobody ever saw fit to improve upon.
Answer: One could make the argument that warfare drives technological advancement. The military budget is among the largest of the federal budgets, and they often fund research and get first dibs on potential applications. As an aside, consider that the US hasn't put astronauts on the moon recently because there is no cold war driving the effort. Any non-military applications are unintended (like mri machines). Even Einstein, who signed a letter to the US President at the time to not drop nukes, had his discovery of mass-energy-equivalence primarily used for military purposes, the studies of which further contributed to science driving military applications.
That said, it is not necessarily the case that only military funding drives technological advancement. But I struggle to find a continual funding source to invest in non-military applications that help further the cause. As a hypothetical, consider that the most dominant countries will have the most funding available for science research and also prioritize military spending to maintain said dominance.
Comment: While I agree that warfare drives technological advancement (at least, those aspects of technology which have military connections), your example of federal budgets and research is completely unconnected to the OP. Industrialization doesn't happen because the government wants it to, and in the early stages of industrialization the government simply isn't in the research business. You seem to ignore the fact that the current research structure is very much a product of WWII and the Cold War.
Answer: I would say Yes. If you are simply not looking for gunpowder, but allow other explosives, Dynamite which was largely used for mining, gets its explosive power from nitroglycerin, which has nothing to do with gunpowder, but would allow your civilization to mine effectively. If another concern is warfare, an often overlooked weapon is the airgun, which has the advantages of being silent, fireable during wet weather, does not produce smoke and can be fired rapidly depending on how much compressed air you have. They just tend to be weaker comparatively, but could defiantly be a driving force in warfare to spur development. You could also use pneumatically launched dynamite as a type of artillery.
Answer: A large military budget. When guns were first developed they were hugely worse than a bow and arrow. However they were much easier to train a soldier to use. If bows had been more popular then the production of guns would not have improved.
The cannon was used because before the cannon an enemy force could hide in a castle until they were ready to fight. A standing army would remove the need for castles, and thus early cannons.
Comment: Any efficient army would still build castles, or at least forts.  There is just too much advantage to having a secure place to store supplies, or a safe place to sleep, or even just a spot where you can leave a small force to defend against larger numbers freeing up more of your army to go kill people and break things.
Comment: A better comparison to a gun than the bow would be the crossbow.  Both require much less training to use accurately, but both require extensive effort to reload between shots.


Increase battery life on XPS 13 9343

Question: I'd like to increase the battery life on my XPS 13 running Ubuntu 14.04. Is this possible? It seems like running a native OS like Windows performs better and would like to maximize the efficiency of the machine.
Answer: There is a package called laptop-mode-tools, which allows extending the life of battery. Another one is pm-powersave from pm-utils package. You can get either with
sudo apt-get install laptop-mode-tools

or
sudo apt-get install pm-utils

pm-powersave is mostly command line, have to be enabled with sudo pm-powersave true. laptop-mode-tools has a graphical front-end to it, written in PyQT.
For more info on both , check out this and this.

Increase battery life on XPS 13 9343


Repeating random forest models to get highest prediction accuracy

Question: I am using a random forest code to run one random forest model and distinguish which variables are important for classification and then to run a second random forest model using only these variables to reduce noise. The problem is that different variables are added to the model on different iterations of this process. I decided to repeat this process 10 times and use the model that produces the highest prediction accuracy (repeated measures sub-sampling from withheld data) as the model I report in my results. Is this a valid method?
Comment: I've noticed that model prediction is quite a bit better if I don't add all variables. Here is a link to the code and references to papers where it's been used: http://evansmurphy.wix.com/evansspatial#!random-forests-model-select/cksm
Comment: Why do you think this would reduce noise? RF are designed to ignore noise on the fly. Unless you have many many variables and most of them are not informative you shouldnt worry about this. If you want to learn a bit more on variabel selection I recommend a video posted on youtube: Random Forests Theory and Applications for Variable Selection.
Answer: Not really. Even though random forest promises to give you an OOB estimate of error rates, this is valid only for one run of the model. If you run the model repeatedly to get better results, you need a cross-validation strategy -- k-fold or LOO cross-validation -- to estimate your true error rates. Otherwise you are just throwing the dice as long as it takes to throw a six.
Comment: Thanks for your response. I am using a cross validation technique (repeated measures sub sampling) to estimate predictive accuracy rather than OOB estimates. I have to run 100 different models, so I wanted to make sure I was predicting using the best combination of variables.


enabling feature access without installing ArcSDE 10.1?

Question: Is there any way to enable "feature access" when publishing a map using ArcGIS 10.1 server, without installing ArcSDE?
Answer: You don't need to install ArcSDE for enabling feature access capability of a map service in 10.1. You however would need to register a database as a geodatabase which will create multiple system tables (geodatabase schema) in this database.
Starting with 10.1, you need to install ArcSDE only when you need to establish application server connection. If you are using direct connect, you are fine since all the libraries needed to access an enterprise geodatabase stored in a supported RDBMS are already shipped with ArcGIS Desktop and you don't need to install anything on top of that. More information on that here.
In 10.2, Esri has introduced a new feature. You can publish a map service with feature access based on a table with a spatial field (for instance, SQL Server native spatial type Geometry) and use this service for web editing without registering a database as geodatabase. More information on that here.
Comment: I have registered a geodatabase however when I am trying to enable the feature access in arcgis manager and then save and restart the service I am getting this error: "Capability: Feature Access requires that the data be on SDE; other types of data sources are not supported"
Comment: Are you able to use ArcMap when authoring your map service and run Analyze to see what layers cause problems and check their data sources? Also, what license do you have for server? You would need Standard or Advanced.


Natural set to express any natural number as sum of two in the set

Question: Any natural number can be expressed as the sum of three triangular numbers, or as four square numbers.  The natural analog for expressing numbers as the sum of two others would apparently be the sum of two "linear" numbers, but all natural numbers are "linear", so this is rather unsatisfying.  Is there a well-known sparser set of integers (or, half-integers, for that matter) that has this property?
Comment: Well, you could always take all the even numbers and $1$; or more generally, $k\mathbb{N}\cup\{1,2,\ldots,k-1\}$. Don't think they will be any more "satisfying", though.
Comment: It's a start, but unfortunately, I don't find that too satisfying either.  The triangular numbers have density 1/n, rather than constant density.
Answer: Assuming Goldbach's conjecture, you can take the set of all primes and successors of primes (plus some small numbers). These have density $2/\log n$.
Not assuming the conjecture, you can take primes, almost-primes and successors of primes (plus some small numbers) - this is the famous Chen's theorem. The resulting density is $\log\log n/\log n$.
Another suggestion is to take the set of all numbers whose binary expansion is "supported" on only odd powers of $2$ or only even powers of $2$. The resulting density is roughly $2/\sqrt{n}$, so this is close to optimal (you need at least $1/\sqrt{n}$).
Comment: [OEIS A126684](https://oeis.org/A126684) says your third suggestion 0, 1, 2, 4, 5, 8, 10, 16, 17, 20, 21, 32, ... is the fastest-growing sequence whose sumset consists of the nonnegative integers.
Comment: Goldbach's conjecture and Chen's theorem also give nice solutions for the "half-integer" variant.
Answer: This math overflow post may be of some interest: https://mathoverflow.net/questions/9731/polynomial-representing-all-nonnegative-integers


What are you doing to prepare for SharePoint 2010?

Question: What best practices are you following to make sure that the eventual release of SPS 2010 doesn't cause major rewrites of your applications?
Answer:
Start by ensuring new hardware is 64-bit.  Deploying 64-bit is our current best practice recommendation for SharePoint 2007.
Deploy Service Pack 2 and take a good look at the SharePoint 2010 Upgrade Checker that's shipped as part of the update.  The Upgrade Checker will scan your SharePoint Server 2007 deployment for many issues that could affect a future upgrade to SharePoint 2010.
Get to know Windows Server 2008 with SharePoint 2007, this post is a great starting point.
Consider your desktop browser strategy if you have large population of Internet Explorer 6 users.
Continue to follow the Best Practices guidance for SharePoint Server 2007.
Keep an eye on this blog for updates and more details in the coming months.

FROM Microsoft Sharepoint Team Blog
Answer: Planning not to install anything on systems that has even the tiniest risk of shutting down business processes? If it isn't broke don't fix (or update it)
If you are head strong on installing it then Virtualisation is a good way of transferring all your applications and data in a safe way from one system to another and ensuring any major issues don't affect your working systems.
Comment: Not headstrong myself, but being able to answer customer questions is always a plus. :)
Answer: I think most people are probably not going to upgrade existing 2007 installations to 2010. Unless there's a very compelling reason. Like Jamie's said, why fix what's not broken? Especially when the fix might just cripple everything. Especially as a bug in SP2 causes existing installations to expire 180 after SP2 installation.
If you have a customer that must have MOSS 2010, I would think the safe thing to do would be to install it side-by-side as opposed to upgrading. SharePoint is such a behemoth with so many ways of doing things that I am afraid an upgrade will not work in 80% of the customized installations out there.
Answer: Good question OP. This was always going to be an issue with SharePoint 2007 apps.
We are still migating from 2003 > 2007, so not really the "typical" company, but yeah just reading lots of blog posts from msdn and other 3rd parties, and playing with the beta.
I think our approach will be the same as with 2003 > 2007. Apart from migrating sites (using custom tools) our applications will be re-assessed in dev and retested prior to deployment to prod. I can see some major re-writes coming with the changes to things such as workflow.


Are the NEMA 10-30 to 14-30 adapters with the extra ground wire valid/legal to use and still adhere to code?

Question: I know the correct answer is to always run a separate ground wire to properly upgrade a 10-30 receptacle to a 14-30 receptacle.  However I noticed amazon sells many of these adapters which instruct you to plug in the separate ground wire to an existing ground slot on a normal 5-15 outlet.  I suppose in theory this all checks out other than looking really odd.  And I don't think they could get away with selling these if they were illegal.  But can you think of a reason this would not be up to code?  What about the ground wire having a smaller gauge on the 5-15 outlet compared to a normal 14-50 outlet?
Comment: Have you found any that have a UL, ETL, or CSA listing/label.  I bet none have those labels and those labels say if they are legal/safe or not.  Amazon gets a lot of stuff from China that they should not sell.
Comment: "And I don't think they could get away with selling these if they were illegal." – Think again! One thing that's important to note is that technically, Amazon _isn't_ selling most of the stuff listed on Amazon.com; most of the listings have a little note saying something like "sold by Asdfhjkl." If you buy one of those items and it ends up killing someone, and you sue Amazon for it, they'll say, "oh, _we_ didn't sell you that item, Asdfhjkl did."
Comment: Interesting point.  Makes you really think twice about the stuff you buy off amazon.
Comment: "What about the ground wire having a smaller gauge on the 5-15 outlet compared to a normal 14-50 outlet?" Yes, this is exactly the problem. I'm pretty sure a 30A dryer outlet needs more than a 14 ga ground from a 15A outlet.
Comment: If you have a valid ground wire for a 30A or larger circuit you can get to by running a ground wire of that size (10 AWG copper or 8 AWG aluminum), you could safely, legally, and to code bring ground to a (properly wired, not a given) NEMA 10 so you could replace it with a NEMA 14. Of course, quite often if you look inside the NEMA-10 enclosure you'll find a disused or improperly bonded to neutral grounding wire already present, because the point where they finally outlawed new installations of NEMA-10 (1996 code cycle) was long after /3 with ground cables were standard.
Comment: Would a 12 AWG solid copper wire work for a ground on a 30 A breaker? Would it trip the breaker before it got too hot? I guess you really need a 10 AWG and a 30 A GFCI breaker?
Answer: Don't buy electrical gear via mail order
Absolutely not. Dangerous rubbish.  You can tell from the obviously Photoshopped spiral on the ground lead, and the use of a "banana plug" on the end of the ground lead ROFLMAO.  This is a "cheap Cheese junk" found on a scummy mail-order site such as eBay.  (and yes, I know you used Amazon; the problem there is Amazon Marketplace, which is is 3rd party listings exactly like eBay and their results are blended in with regular results.  Amazon bundles their "Amazon Fulfillment" warehousing and shipping service for the seller, which is why it ships with Prime, so it feels like an Amazon item. The text which mentions it being a 3rd party seller is right under the "Buy" button, but it's also the smallest text on the page.
If shipped direct from those people helping Russia, Customs could intercept and confiscate the items (if they had unlimited resources). But Amazon's warehouses are able scoff the law due to legal chicanery. (government agencies must choose their fights carefully, lest they have to go back to Congress to ask for more funding for lawyers).
But it says UL!
If I build you a "Suicide Cord" using two UL-listed NEMA 14-30 plugs and UL-listed 10/4 cordage, is that assembly UL-Listed?  LOL of course not, UL doesn't list suicide cords for obvious reasons.
Same deal here.  All they are claiming is that instead of using random Chinese cordage, they are actually getting a proper UL-listed 10/3 cordage imported.  That may or may no be true, but by making the claim that particular way, they make it difficult for UL's lawyers to force them to stop.
But that assembly is absolutely not UL-Listed. No way, no how. The item will not have a label on the cord indicating UL Listing.
But all they need to do is say a little for "wishful thinking" will take over. We live in a post-fact world. Reality is anything you want! Don't like who won the election? Easy, they didn't win the election!  Don't want to believe humans are causing climate change? Blame it on anything!  Don't want to wear a mask? Germ theory is only a theory! So that listing will nicely appeal to that sensibility.
Comment: Would UL approve an adapter which allowed use of a 4-prong plug with a 3-prong outlet, if the adapter included a ground fault circuit interrupter?  I would think that such an adapter should be fairly safe, under the same principle that allows upgrading 15/20-amp outlets with a "no equipment ground" GFCI.
Comment: @supercat I can't see why not, unless there's an issue with the GFCI controls being inaccessible.
Comment: @supercat: I saw some old instructions with a four prong dryer that said if you have a three prong outlet, save the cord from your old dryer, attach leads from old cord (they're donut hole leads that slip over bolts with nuts you tighten down), and run the included banana connector from the fourth bolt to a screw on the outlet face. Clearly this would only work if said screw were grounded. They got this approved somehow.
Comment: @Harper-ReinstateMonica: It would be nice if UL could recognize more kinds of protective equipment that could enhance the safety of older wiring without requiring that it be reworked to modern standards.  A GFCI-protected dryer outlet with an 18ga grounding pigtail in series with positive-temperature-coefficient resistor and solid-state current limiter would provide better safety than a dryer outlet with a full-size grounding conductor but no GFCI, or one with a GFCI and no grounding connection, but I don't know of any standard for such devices.
Answer: Amazon sells stuff all over the world from vendors all over the world so what's legal elsewhere might not be legal here in the USA. In the USA, it would have to be UL listed to be used. You'd have to check the listings for each adapter to see if it qualifies. Amazon is famous for selling junk that's not UL listed and since you don't have a link to the adapter, we can't check it.
Comment: Self declaring it 'meets the standard' is not the same as actually having it pass the tests and be listed. Exactly what it is listed under also matters.
Comment: @Fred It doesn't actually say it's UL listed, which is what is needed. All that statement says is that they claim the main cable (not the green ground wire) is STW 10/3. That has no bearing on whether or not the adapter is UL listed.
Comment: Sellers often lie. (Although I have no idea whether this device, or any comparable device, is UL listed for use in the United States. But sellers on Amazon have zero accountability to anybody, and can say whatever they want.)
Comment: It seems unlikely that UL would truly approve of obtaining ground for a 30A circuit from a 15A circuit, as this device enables. The NEC definitely doesn't allow retrofitting ground for a 30A circuit to a 15A or 20A ground.
Comment: Here is the link:

https://www.amazon.com/Adapter-14-30R-Female-10-30P-Converter/dp/B08PFCSDWV/ref=sr_1_6?crid=1L6ZXUO0DCLOS&keywords=10-30%2Bto%2B14-30&qid=1690643203&sprefix=10-30%2Bto%2B%2Caps%2C124&sr=8-6&th=1

Apparently it does meet the UL requirements or at least says it does as indicated by this description:

"【SAFETY】 The dryer plug adapter that meets the UL standard has a copper core that meets the quality requirements of STW 10/3 AWG and a durable insulating PVC protective layer."
Comment: I agree and honestly I'd feel better sticking to the 10-30 neutral bonded to ground dryer set up than using one of these adapters.
Comment: @nobody  Excellent point.
Comment: Then it's just a bad idea.  I see some comments on some of the adapters that their dryer unit runs but the heating element does not work when used with the adapter.  No way I'm trusting these things, thanks for all the comments.


Can my employer's payroll company be liable for not withdrawing enough State taxes from my income?

Question: My employer's payroll company did not withdraw the correct percentage of state taxes from my year's worth of paychecks.  I'm now liable for $2,000 in state taxes.  Can the payroll company be held fully or partially liable for this amount?
Comment: The question I'm linking as a potential duplicate may look different, but the answer is effectively the same. In short, you would need to pay that tax either way, its now you "got" to delay paying it until the end of the year. It does not seem possible to hold anyone else responsible for paying that tax, but if you pay penalties / interest to the IRS, you maaaaaaay be able to fight for that to be covered.
Answer: No, a payroll company isn't liable for paying tax you owe. They calculate how much should be withheld from each paycheck and direct your employer to pay it to the tax authority.
The amount withheld isn't always a perfect match to your tax liability because, because you may have other income -- like from other companies, interest income, or stock sales.
Withholding is controlled by the W-4 at the federal level, and similar form at the state level. Review your elections on the W-4 form to make sure they reflect your family tax situation.
In the highly unlikely situation that the payroll processor made a mistake, and that resulted in you owing underpayment penalties, you might have some luck in getting them to pay the penalties. But I doubt you are in that situation. And regardless, you are personally responsible for your own tax bill.
Comment: I understand I'm responsible for paying my own taxes; however, my company's payroll department, or in this case, payroll company, should be held responsible for deducting the correct percentage of taxes based on the state I live in.


Phonegap - Updating JavaScript and CSS without submitting the app to appStore

Question: Is it possible to update the content of WWW folder in phonegap without submitting the app every time you make changes to appStore?
Is there any legal issue with it?
Answer: Short answer - yes, you can - but you need to relocate www before you can write to it.
Long answer - tighten up your shorts pilgrim, this might get bumpy....
So, when you package your app, the app bundle contains your www directory and all of the various and sundry parts of your PG self contained web app.  Everything that is part of the app bundle is static - so it cannot be written to.  You can, however, write to the NSDocumentDirectory for your application - it's private sandboxed storage area.
The first step is to (upon launch) copy your www folder into the NSDocumentDirectory.
Second, you'll need to override the CDVCommandDelegateImpl pathForResource method in order to point PG at the new www location.
At this point your app should be operating as it did when contained within the app bundle.  One notable exception is that each of the files can now be modified.
My app is a base product which can have add-on content.  If I included all of the add-on content, the app would be several hundred MB in size.  So, I include the basic app with a single (sample) data package, and as users need to extend the product, they select additional data packages which are downloaded, extracted and copied into the appropriate subdirectory of the www folder as it exists in the NSDocumentDirectory.
As a bonus, if I find a bug in HTML - or want to add a feature, I can do so without resubmitting the app.  The only reason I need to resubmit the app is if there is an Objective-C bugfix.
Comment: Could you put the code that accomplishes this on github or somewhere else? I would really appreciate being able to see a working copy.
Answer: This is just adding onto Michael's answer.
1 ) Copy your www folder into the NSDocumentDirectory:
   - for phonegap ios, add this to /ProjectName/Classes/AppDelegate.m

- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions
{
    CGRect screenBounds = [[UIScreen mainScreen] bounds];

    self.window = [[[UIWindow alloc] initWithFrame:screenBounds] autorelease];
    self.window.autoresizesSubviews = YES;

    self.viewController = [[[MainViewController alloc] init] autorelease];
    //self.viewController.useSplashScreen = YES;

    // Set your app's start page by setting the  tag in config.xml.
    // If necessary, uncomment the line below to override it.
    // self.viewController.startPage = @"index.html";

    // NOTE: To customize the view's frame size (which defaults to full screen), override
    // [self.viewController viewWillAppear:] in your view controller.

    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];

    if ([[NSUserDefaults standardUserDefaults] boolForKey:@"AppFirstLaunch"])
        {
            NSLog(@"App already launched!");
        }
        else
        {
            [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"AppFirstLaunch"];
            [[NSUserDefaults standardUserDefaults] synchronize];

            NSLog(@"App launched for first time!");

            BOOL success1;
            NSError *error1;

            NSFileManager *fileManager1   = [NSFileManager defaultManager];

            fileManager1.delegate         = self;

            NSArray *paths1               = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

            NSString *documentsDirectory1 = [paths1 objectAtIndex:0];

            NSString *writableDBPath1     = [documentsDirectory1 stringByAppendingPathComponent:@"/www"];

            success1                      = [fileManager1 fileExistsAtPath:writableDBPath1];

            if ( success1 )
            {
                NSString *defaultDBPath1 = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"www"];
                NSLog(@"default SUCCESS / AppDelegate path %@",defaultDBPath1);
                success1 = [fileManager1 copyItemAtPath:defaultDBPath1 toPath:writableDBPath1 error:&error1];
            }
            else
            {
                if (![[NSFileManager defaultManager] fileExistsAtPath:writableDBPath1])
                    [[NSFileManager defaultManager] createDirectoryAtPath:writableDBPath1 withIntermediateDirectories:NO attributes:nil error:&error1];
            }
        }

    return YES;
}

2 ) To override the default path ( orig. set to www folder ), within CordovaLib/Classes/CDVCommandDelegateImpl.m, replace the body of the function:

-(NSString*) pathForResource:(NSString*)resourcepath
 with:

- (NSString*)wwwFolderName
{
    NSArray *searchPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    return [NSString stringWithFormat:@"%@/www",[searchPaths objectAtIndex:0]];
}

- (NSString*) pathForResource:(NSString*)resourcepath
{
    NSBundle* mainBundle           = [NSBundle mainBundle];
    NSMutableArray* directoryParts = [NSMutableArray arrayWithArray:[resourcepath componentsSeparatedByString:@"/"]];
    NSString* filename             = [directoryParts lastObject];

    [directoryParts removeLastObject];

    NSString* directoryPartsJoined = [directoryParts componentsJoinedByString:@"/"];
    NSString* directoryStr         = [self wwwFolderName];

    if ([directoryPartsJoined length] > 0)
    {
        directoryStr = [NSString stringWithFormat:@"%@/%@", [self wwwFolderName], [directoryParts componentsJoinedByString:@"/"]];
    }

    NSLog(@"default path %@",directoryStr);

    if (![[self wwwFolderName] isEqualToString:@"www"])
    {
        return [NSString stringWithFormat:@"%@/%@",[self wwwFolderName],@"shared/index.html"];
    }

    return [mainBundle pathForResource:filename ofType:@"" inDirectory:directoryStr];
}

Other References:

Copy Folder from main bundle to documents directory in iphone
How to detect first time app launch on an iPhone
Comment: I like your code better than mine - thanks for expanding upon my method, I learned something from you.
Comment: It was inevitable that a customer would want this feature in an android app - do you have a suggestion on where I need to start to accomplish the same thing?
Comment: I actually took your original idea and ran with it for a work related project.  This allowed us to slim down our app to a few core parts (700mb to 38mb) that was initially loaded with the app, and then we used different manifests to indicate which parts could be updated or required downloading.
Answer: Well, since Phonegap is using WebView, you can store parts of your code in localstorage and eval it, and every time the user has internet access, you can download updated parts of the code from your server and place them in localstorage again.
As for the files, you can't replace them as they are packaged.
Though this requires you to design a clever "updating" logic since it is a bad idea to keep your users uninformed about the updates and new features/fixes.
Good luck!
Comment: Do not use localstorage. iOS will recycle it if it's low on memory, it cannot be counted on
Answer: No, the www folder is packaged in your application so if you want to update those files you'll have to resubmit to the app store. Other platforms like Android and BB will allow you to host your app remotely but if you want to be in the iOS app store those files will need to be local.
Comment: I know that the files has to be local, but what if we replace the files in www via a plugin or native code?
Comment: @Ard you can't write to the www directory. It is part of your app and if you were able to modify the contents it would change the checksum of the app thereby making it invalid. It is a security feature of the OS for you not to be able to modify the contents of the www directory.


Where is the Starcraft II custom map folder?

Question: I downloaded a custom map but I don't know where to put it in order for it to appear in the Custom Game map selection menu. Does anyone know where is this custom map folder ?
I play on MacOS X but I think the only difference between the Windows and the MacOS version is only the installation path.
Comment: For people who found this thread looking for the location of the maps they downloaded in SC2: the program [StarBank](http://www.d3scene.com/forum/starcraft-2-custom-maps/67976-starbank-starcraft-ii-bank-file-editor-custom-map-saves-v1-7-a.html) *(Written by a very mysterious and handsome gentleman)* will do that for you.  However, that there currently is no Mac support...
Answer: Actually, the way Blizzard has custom games working at the moment, it is not as simple as navigating to a folder to select the map.  Many view this as a downfall in their current system, but this site is not the place for such arguments.
Rather, to answer your question, the only way for you to play this map is to either find it in the search engine for custom games online or to publish it yourself.  Ideally, you can find it in the search engine online, but there are a limited number of maps that appear in that, so if the map you want to try is unpopular, your only option is to publish it yourself.
You have to open the map in the map editor and publish it just as you would any of your own maps.  Unfortunately, this will create a copy on their server, and anyone found playing your copy will be counted differently from the original author's copy, which means that the stats for determining popularity will treat them as separate maps even though they are the same.  It is very difficult for a new map to make its way up through the popularity list with this system.
This Team Liquid forum post goes into great detail about the shortcomings of the current custom map system and the workarounds for it.
Comment: The best solution to play a custom map is to publish it oneself if the map is not part of the top 50. Too bad for the author, I hope this system will change.
Answer: The FAQ of the StarCraft 2 Map Editor (called "GalaxyEditor") gives some short information about the location and handling of custom maps:

How can I play maps i've previously downloaded? (Including the official maps)
Your downloaded maps can be found two different ways. The easiest of the two, is to go to File > Open > Battle.net Tab within GalaxyEdit. Otherwise, you need to search your Battle.net Cache for "*.s2ma" and then convert the .s2ma file to .SC2Map. However, the .s2ma filenames are just hashes of their true name, so good luck trying to find the map you need!
The Battle.net cache can be found at:
  C:\ProgramData\Blizzard Entertainment\Battle.net\Cache -- Win Vista/7
  C:\Documents and Settings\All Users\Application Data\Blizzard Entertainment\battle.net\Cache\ -- Win XP
The folder containing Maps created by GE can be found:
  %USERPROFILE%\Documents\StarCraft II\Maps

http://us.battle.net/sc2/en/forum/topic/189279023
Answer: You can open it in StarCraft II Editor and then click File/Test document.
Answer: Download the map file,
Place in a folder I name mine Starcraft2 maps,
Open new folder containing your downloaded maps
Right click on a map choose "Open With"
click browse and find your starcraft launcher file
      Mine is Here C:\StarCraft II
Once in this folder click the file StarcraftII
Click Open
"NOTE" Make sure the check box is marked that says
           "Always use the selected program to open this kind of file"
Then click OK

If the checkmark box is checked you will not need to do any of this again you will just need to go to your new maps folder and double click on the map for future play :)
The map will then open in Starcraft II and you can play it.


Is it possible for two users to mount the same Shared disk on Time Capsule? (On one Mac.)

Question: The situation is this; 1 shared Mac Mini with user switching.  If I leave the Shared disk mounted and the other user logs in, they get prompted for Administrator credentials (which disconnects me.)  We both need to be able mount and use the share without disrupting processes running under each user.
Comment: I think the problem may be that automount is trying to reuse /Volumes/Data.  Maybe I could just hard mount it for each user to their own path and stop accessing via Finder.

I'll have to try this tonight unless any one else can test/confirm.
Answer: I just tried the same thing, without any problems... Do you use user accounts to authenticate the users on the time capsule ? If yes, you should probably configure it to use the airport network. With this, both users will connect with the same "account", and should be able to use the same share concurrently (that works for me)
Here is a screen cap of the setting (sorry, it's in french) :
Comment: I do use accounts, but I use seperate accounts in order to have private folders as well as the shared.  I'm hoping I can find a solution that allows for this.
Comment: I think you will not be able to do this : the only way to allow this is to have the "shared" folder owned by a group, and the "private" folders owned by their user. But the Time capsule does not support groups management AFAIK...


What can I use to convert the output wave from an inverter from a modified sine wave to a pure sine wave without much energy loss?

Question: I use an inverter (600 W) to convert from DC 12 V to AC 220 V 50 Hz, but the wave output from the inverter is a modified sine wave, which causes problems when operating some electrical appliances (high temperature, noise, etc.) I also find it difficult to obtain a current inverter that produces a pure sine wave so I am working on converting the resulting wave from a modified sine wave into a pure sine wave using (a coil or resistor) and a capacitor, but the wasted energy when using the copper coil is as large as it is greater if you use a resistor.
Comment: Actually using an inductr/capacitor filter WON'T generate heat -- it will filter, but there is nothing in it that absorbs heat. Basically, it prevents the higher harmonics from passing though the filter.
Comment: Welcome! _"I also find it difficult to obtain a current inverter that produces a pure sine wave"_ I find 158 to choose from on Amazon alone. There are many other vendors as well. If you do intend to filter out the harmonics of your existing inverter, have you hooked up your oscilloscope to the output (be aware of voltage rating on your probes and scope input) and tried to simulate it in your simulator of choice?
Comment: Please edit the question and add a list of the loads you are trying, and what are the symptoms. Modified sine wave is a problem with induction and some synchronous motors and... not much else in my limited experience.
Answer: The simplest solution is to rectify the output and wire it to a synthetic sine wave inverter.
I'm not actually kidding.
Given that this is a fair amount of circuit design (even with pre-baked (single IC) solutions available, a complete design still requires a handful of transistors, capacitors, several diodes, and a couple dozen resistors, and all must be placed and wired correctly on a PCB), perhaps you can begin to appreciate how bad a passive solution must be.
I can put it another way: if you had enough copper and iron for a passive filter network (which might still not even be compatible with the inverter as such; it might not start up into such a load, or other characteristics will be lacking as a tradeoff) -- why wouldn't you simply sell it for scrap and buy a better quality inverter?
More seriously: the most likely candidate would be a ferroresonant transformer.  It's not obvious to me whether a modified sine inverter would be at all happy driving one of these, but suffice it to say, a 600VA unit weighs more than a few kg (hence, is literally worth a modest amount as scrap).  They run hot, and are rarely used and therefore expensive to buy -- if you can find one in your market at all.
Answer: you try using sine wave circuit gs002 it only consumes 0.01a, if it's a homemade H-bridge it also consumes very little power


7 segment display

Question: i recently bought a 7 segment display for research purposes. I have connected this to the raspberry pi and i got an output. The thing is that, the segment has 4 digit display and all the displays show the same output. Is there any other alternative way where i could display different outputs in each of the display. i have posted the picture of the display and also the pin configuration. Also can i connect the 3.3v pin to gpio pin of the raspberry pi and resist the flow of voltage? i got the product from the below link https://www.amazon.in/Delson-Electronics-Digit-Segment-Anode/dp/B076HV47XF

Comment: Each segment has two sides (they are LEDs.) However, all of the LEDs for each digit are tied together on one side. Then all four of the "A" LEDs have another side tied together. This is why you get the same digit on every one of the displays. To get different values you need to "multiplex" the unit. This means that you present some setting for A-H, and then activate D1 ONLY. Do that for a while, then turn off D1, set up a different setting for A-H, then activate D2 ONLY. Etc. Once you get done with this for D4, you repeat for D1 again, and so on. Read up on multiplexing 7-seg displays.
Answer: You have to use Multiplexing.
The eye has a response time, this means if you flash the LED very fast, from your eye you will see that is on.
This LED panel is designed so that each 7 segment digit is "flashed" one after the other, from the eye view it will look like they are on.
This method is used to avoid having to use too many input / output on the controller.
To do so, you need to quickly switch on the first segment for a few milliseconds with the correct value to display. Then you switch it off, and you switch on the next one with another value and so forth for the other two.
It's basically the same way a TV or most led display works.
Here is a link that explains it

7 segment display


cocos2d Guitar strings for iPad

Question: I am starting to work with Cocos2D and so far learned a lot. But I can't find how to simulate a ccDrawLine so that it behavior like a guitar string, meaning, when touching a ccDrawLine, that it plays sound and moves the ccDrawLine where the user is touching it.
Answer: I've no experience with Cocos2D, but the process to simulate a guitar string may be something like so:

Draw your line;
Add a valid "touch area" around the string (as the small string may not be thick enough to reliably register a touch);
When you detect a touch within the bounds of the touch area, animate the line to simulate the strum, and play the sound (and fade it out, to simulate the slowing of the vibration).

Another thing to consider may be the possibility of overlapping sound. What if the user rapidly touches the same string? The previous sound should stop before the new sound starts. Or, more naturally, no sound should play whilst the user still has their finger on the string, and should instead only produce a sound once the user has "plucked" the string (ie. ended the touch).
I'm not sure if Cocos2D has its own touch event handler (I imagine it would), but perhaps this SO post might help: how can i detect the touch event of an UIImageView
EDIT: It turns out, Cocos2D does have its own touch event handler. See: How can I detect touch in cocos2d?
Answer: I would go about this by using a free and simple vector art tool such as Inkscape. It will allow you to make some realistic-looking strings of different thicknesses/textures. Import the strings into your app as different sprites. Cocos2d has a lot of options for easily detecting things like 'isTouchOnNode', which perfectly fits your scenario. Specifically, http://kobold2d.com does wonders for easy touch detection and node selection.
I don't have access to Xcode at the moment, so this may not be verbatim code:
<code>/* if you use Kobold2d */

CCSprite* Gstring = [CCSprite spriteWithFile:@"Gstring.png"];
KKInput* input = [KKInput sharedInput];
if ([input isAnyTouchOnNode:Gstring touchPhase:KKTouchPhaseAny])
{
// play a sound.
// this code will become extremely complicated
// if you want a realistic sound
}
</code>
Keep in mind that cocos2d may not be the best engine to use if you are planning on making a sound/music heavy app. It has a very basic 'SimpleAudioEngine' from CocosDenshion that is not designed to handle the many overlapping sounds a guitar can make.

cocos2d Guitar strings for iPad


measuring resistivity of copper wire

Question: I have a power supply, multimeter, and a copper wire  with cross sectional area (A) A= 2.14*10^-3 m^2, Length L = 0.13 m and the resistivity of copper is p=1.7 × 10-8. The goal is to find the resistance of my copper wire, but I'm not sure what other instruments I need to determine the resistance, or how to setup the circuit to find out the resistance. After using the resistance equation, I found that the resistance should be about 1*10^-6 (ohms), but I cant get close to that answer.
How should the circuit be setup?
Comment: How much current can your power supply provide? Do you have a second multimeter, or does the power supply have an internal ammeter? What is the lowest voltage your multimeter can accurately measure?
Comment: You are describing testing a piece of "wire"  about the size of a soda can. Fix your figures first, or find a new piece of wire, more like 1 m long and 1 mm diameter, or 1x10^-6 m^2 area. It is possible to measure the resistivity of a piece of bulk copper, but you'd need hundreds of amps, and the calculations of the current flow are quite different to the simple formula.
Comment: @tomnexus He does not need any power supply. I think it is just a homework, and "power supply" in the question is supposed to distract students.
Comment: Measuring the resistance of very small resistances, like a copper wire with a multimeter is unreliable. I suggest using a Thomson bridge, which gives much better accuracy at low resistance values.
Comment: Well, if the OP is trying to measaure 1 uOhm, it will be rather difficult, as tonnexus points out. Even 1000 A will only produce 1mV.
Comment: To the OP, if you have this wire handy, can you please post a picture of it? I believe you must have mis-calculated the cross section area. What you describe in your question would be a very wide and short piece of "wire" that is more like a bar than a wire.
Answer: In general, you use a power supply to run a known current through the wire, and measure the voltage drop using a voltmeter accurate to the mV level. Then you use Ohm's law to calculate the resistance. V = I * R. V is the voltage on the voltmeter, I is the current, and R is what you want to know. You probe with the voltmeter at the exact location where you want to know the resistance.
Note, copper is a good conductor, but its conductivity is fairly sensitive to temperature. If you run so much current through it that it warms up, the resistance will change. So best to measure reasonably quickly, then disconnect the power.
Further reading:
Four wire resistance measurement
https://www.allaboutcircuits.com/textbook/direct-current/chpt-8/kelvin-resistance-measurement/
Copper resistance temperature coefficient
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html
Basically, for every degree of temperature increase, the resistance increases by 0.4%. So if it is 1 Ohm at 25C, ti will be 1.004 Ohms at 26C, and so-on.
In this specific question, I have my doubts that the dimensions are correct. A cross section of 0.00214 m^2 would be a very large wire, around 52mm (2") in diameter. Measuring the resistance of such a wire would require a very large current to give rise to any appreciable voltage.
Answer: As MKEITH said, copper has a temperature coefficient; its 0.4%, or 4,000 ppm, per degree Centigrade.
Copper, as with other materials has a thermal timeconstant (or, when inverted, a parameter named thermal-diffusivity).
For a cubic meter of copper, the time constant is 9,600 seconds (about 3 hours).
For 10cm cube (4" on a side), the time constant is 100X faster or 96 seconds.
For 1cm cube, the time constant is another 100X faster, or 0.96 seconds.
For 1mm cube, Tau is another 100X faster, or 0.0096 seconds.
Thus measurement has be made extremely quickly, or the temperature rise must be
very small.
Answer: In addition to my previous answer, there is a simpler way to calculate that resistance.
https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity
\$ R= ρ \times \frac{l}{A} \$
\$ R= 1.7 \times 10^{-8} \Omega.m \times \frac{0.13 m}{0.00214 m^{2}} = 1.0327 \mu\Omega \$
Comment: That seems like a high resistance for round copper bar which is 5 cm in diameter and 17 cm long.
Comment: @AndrewMorton You are right, a missed one character. Fixed. Thanks for pointing out.

measuring resistivity of copper wire


General Compressibility Of Various File Formats

Question: Has anyone come across list of which file formats generally compress well (in general algorithms)?
Generally, text files .txt compress well, and media-files (.mp3, .avi, etc) do not compress well.
I'm looking for a list (or database) of file formats so I can answer the question, "Will a general, lossless algorithm compress a <.xxx> file?".
EDIT: Of course by nature, random data, media files, and compressed data do not compress well.  That is not my question.
Question:  Where can I look up descriptions of file-formats, specifically to discover if the format already contains compression?
Examples:
AutoCAD Drawings, Various Microsoft Office formats, Oracle Database .DBF files, Adobe PDF files, Outlook PST files, etc
Comment: in general all data with lots of common patterns compress very well, data with noise does not. files which are compressed already fall into the latter category of files.
Comment: Right now, your question is asking for anecdotes, which makes it unfit for Super User. Of the most common compression formats, LZMA generally achieves the best compression, but it's also the slowest algorithm. Pseudo-random and already compressed data cannot be compressed by any of these algorithms.
Comment: In general, files that are already compressed to some degree will not compress well.  Most standard audio and image formats are compressed.  Those that aren't are not generally used for internet operations because they take so much longer to transfer.
Comment: See edit to question.
Answer: From what I can understand of your question, it sounds like you have tried to compress an already compressed file. File formats such as .png, .jpg, .avi, pdf, .mp4 and many others may already have their data in a compressed format. Attempting to compress such files will not significantly reduce their size.
Comment: See edited question.


Proof of binomial coefficient formula.

Question: How can we prove that the number of  ways choosing $k$ elements among $n$ is    $\frac{n!}{k!(n-k)!} = \binom{n}{k}$    with $k\leq n$?
This is an accepted fact in every book but i couldn't find a proof.
Answer: Well, let's first make sequences (ordered lists of distinct elements) of length $k$ from the $n$ element set.There are $n$ ways of picking the first element, $n-1$ ways of picking the second, ..., $n-k+1$ ways of picking the $k$th element. So there are $$n(n-1)\cdots (n-k+1) = \frac{n!}{(n-k)!}$$ such sequences.
But we want to count unordered lists, i.e., for each sequence, we want to identify the $k!$ permutations of its elements (each of which was counted separately above) as the same list. Hence the number of unordered lists is $$\frac{\frac{n!}{(n-k)!}}{k!} = \frac{n!}{k!(n-k)!}.$$
Comment: @usainlightning maybe try writing out all the ordered sequences for some small $n$ and $k$ and grouping them by those that have the same numbers. You will see that each group has $k!$ sequences, so dividing by $k!$ is like shrinking each group into one "element" (the set of numbers in the sequences in that group). Not sure if that makes sense
Comment: I understand where the $\frac{n!}{(n-k)!}$ and $k!$ come from I just do not understand logically speaking why you divide the two to switch from ordered to unordered. (+1)
Comment: @usainlightning another way to think about it: we have (# ordered sequences) = (#groups)(size of each group) where a group is the set of sequences with the same set of numbers. You want to count #groups and you have $\frac{n!}{(n-k)!}=$(# groups)$k!$.
Comment: Can you directly count unordered sequences? Instead of first counting ordered and then dividing out the orderings?
Comment: @user129393192 That's a good question and I'm not really sure of a good answer. The only thing I can think of right now is using induction (basically arguing that the count of $k$-subsets of an $n$-set satisfies Pascal's rule). I'm not sure that counts (no pun intended!)
Answer: Notice that given $n$ objects $\{a_i\}$ and $n$ positions, there are $n$ possible positions for $a_n$. Once we have placed $a_n$, there are $n-1$ remaining positions for $a_{n-1}$. Once we have placed $a_n$ and $a_{n-1}$, there are $n-2$ positions left for $a_{n-2}$, and so forth. Thus, there are
$$
n(n-1)(n-2)\cdots3\cdot2\cdot1=n!
$$
possible ways to arrange the $n$ items.
Suppose we divide the $n$ items into $k$ white objects and $n-k$ black objects. For each arrangement of the white and black objects that looks the same, there are $k!$ rearrangements of the white objects and $(n-k)!$ rearrangements of the black objects. Since there are $n!$ rearrangements of the $n$ objects, there must be
$$
\frac{n!}{k!(n-k)!}=\binom{n}{k}
$$
arrangements of the $k$ white and $n-k$ black objects that look different.
Answer: Perhaps it will help you go over the permutation formula first $\frac {n!}{\left( n-k \right)!}$ and then thinking about the adaptation we need if we are to disregard order. It is easier this way.
Answer: First, for $k\leq n$ we must construct a $k$-permutation from an $n$-element set. We can choose the first item in $n$ ways, the second item in $n-1$ ways, whatever the choice of the first item,..., and the $k$th item in $n-(k-1)$ ways, whatever the choice of the first $k-1$ items. By the Multiplication Principle the $k$ items can be chosen in $n(n-1)\cdots (n-k+1)$ ways. We can rewrite this as $${n(n-1)\cdots (n-k+1)(n-k)!\over (n-k)!}={n!\over (n-k)!}.$$ Thus $P(n,k)={n!\over (n-k)!}$. By a $k$-permutation from a set $S$ of $n$ elements, we have an ordered arrangement of $k$ of the $n$ elements. Since we are concerned with the number of ways we can choose $k$ of the $n$ elements we want the number of unordered arrangements (subsets). Since each arrangement has length $k$ we can permute them in $k!$ ways. So the number of unordered arrangements of the elements of S is ${n!\over k!(n-k)!}$. Thus for $k\leq n$ $$C(n,k)={n!\over k!(n-k)!}.$$
Answer: if you have $k$ number of black and $n-k$ white balls what is your change of getting 1 white then 1 black then 1 white... it is $\frac{(n-k)!k!}{n!}$ and if your change of getting $1$ combination is $\frac{(n-k)!k!}{n!}$ how many combinations are there answer is $\frac{n!}{(n-k)!k!}$.this is how i think it but it can be flawed.
Answer: Perhaps it is worth mentioning a method of solution that might appear a bit far-fetched, but which is an excellent introductory example to the theory of generating functions, for which the book generatingfunctionology by Herbert S. Wilf is highly recommended.
Write $\dbinom{n}{k}$ for the number of choosing $k$ objects out of $n$. Consider the polynomial
$$
(1 + x_{1}) (1 + x_{2}) \cdots (1 + x_{n})
$$
in the $n$ indeterminates $x_{1}, \dots, x_{n}$. It is easy to convince oneself that this polynomial has exactly $\dbinom{n}{k}$ monomials of degree $k$. If one now sets $x_{1} = \dots = x_{n} = x$, where $x$ is another indeterminate, each such monomial reduces to $x^{k}$, so that one obtains that
$$
(1 + x)^{n} = \sum_{k = 0}^{n} \dbinom{n}{k} x^{k}.
$$
Now use Taylor's theorem for polynomials to obtain the required formula.
Let me stress that this might look totally overkill in this relatively simple setting. But the method has tremendous potential.
Answer: Let $X$ be a nonempty finite set with $n$ elements. For the integer $s$ define
$$ \mathcal{P_s} (X) = \{ A \subset X \mid |A| = s\}$$
and for integer $r$ satisfying $0 \le r \lt n$ define
$$ \mathcal{B_r} (X) = \{ (A, b) \mid A \subset X \; \land \; |A| = r \; \land \; \displaystyle b \in A^{\complement }\}$$
Observe that $|\mathcal{B_r} (X)| =\, _n C _r \times (n-r)$.
Consider the function $\beta:\mathcal{B_r} (X) \to \mathcal{P_{r+1}} (X)$ defined by
$$ (A,b) \mapsto A \cup \{b\}$$
Now given any $B \in \mathcal{P_{r+1}} (X)$ we can write
$$ \beta^{-1}(B) = \{ (B\setminus\{b\},b) \mid b \in B\}$$
and so $\beta$ is a surjective function with a
$$ (r + 1) \text{ : } 1$$
mapping correspondence.
Therefore
$$\tag 1 |\mathcal{P_{r+1}} (X)| =\, _n C _{r+1} = \frac{_n C _r \times (n-r)}{r+1}$$
Since $_n C _0 = 1$, you can use induction to show that the number of subsets with $k$ elements from a set with $n$ elements $(0 \le k \le n)$ is given by this formula:
$$ _n C _k = \prod_{i=0}^{k-1} \frac{n-i}{i+1} \quad\text{(equal to } 1 \text{ when } k = 0 \text{)} $$
To complete the proof, fix $n$ and observe that
$ _n C_0 = \frac{n!}{0!(n-0)!}$
For $0 \le r \lt n$ assume that
$ _n C_r = \frac{n!}{r!(n-r)!}$
From $\text{(1)}$, all that is required to complete the (finite) induction is to show that
$$ \frac{n!}{(r+1)!\,(n-(r+1))!} = (\frac{n!}{r!\,(n-r)!})(\frac{n-r}{r+1})$$
But using the fact that $t! = t \times (t-1)!$,
$ (\frac{n!}{r!\,(n-r)!})(\frac{n-r}{r+1}) = \frac{(n-r)\,n!}{(r+1)\,r!\,(n-r)\,(n-r-1)!} = \frac{n!}{(r+1)!\,(n-(r+1))!}$
and we get the desired result.
Answer: If you have 5 people (A, B, C, D & E) but wants to build a team of three people, the most number of ways you can do is 5x4x3= 60 ways. But realize that team ABC and CBA is basically same team.
So for three people, you can have 3x2x1=6 different combinations.
Meaning that, making a team with 5 poeple with 3 positions, you can have total (5x4x3) / (1x2x3) = 10 different combinations. This number 10 is the 3rd number on 5th row of Pascal's triangle. This basically tells us the number of combination we can have.
And (5x4x3) / (1x2x3) = 5! / (3! x 2!) = C (5, 3)
Comment: Welcome to MSE. Your answer adds nothing new to the already existing answers, posted years ago.

Proof of binomial coefficient formula.


Spark Scala - How do I iterate rows in dataframe, and add calculated values as new columns of the data frame

Question: I have a dataframe with two columns "date" and "value", how do I add 2 new columns "value_mean" and "value_sd" to the dataframe where "value_mean" is the average of "value" over the last 10 days (including the current day as specified in "date") and "value_sd" is the standard deviation of the "value" over the last 10 days?
Comment: If data can be naturally partitioned by some (for example year or month) you can use a solution described in http://stackoverflow.com/q/33207164/1560062 Otherwise this problem is not a good fit for DataFrames.
Comment: Thanks! Average (mean) works beautifully over window partitions but not "stddev". Do you know how to do standard deviation on WindowSpec?
Comment: Build your own from basic expressions. See: http://stackoverflow.com/a/31791275/1560062
Answer: Spark sql provide the various dataframe function  like avg,mean,sum etc.
you just have to apply on dataframe column using spark sql column
import org.apache.spark.sql.types._
import org.apache.spark.sql.functions._
import org.apache.spark.sql.Column

Create private method for standard deviation
private def stddev(col: Column): Column = sqrt(avg(col * col) - avg(col) * avg(col))

Now you can create sql Column for average and standard deviation
val value_sd: org.apache.spark.sql.Column = stddev(df.col("value")).as("value_sd")
val value_mean: org.apache.spark.sql.Column = avg(df.col("value").as("value_mean"))

Filter your dataframe for last 10 days or as you want
val filterDF=df.filter("")//put your filter condition

Now yon can apply the aggregate function on your filterDF
filterDF.agg(stdv, value_mean).show


I am trying to run the iOS simulator

Question: I am trying to run the iOS simulator on my mac but I can't find it when i search in spotlight. I have Xcode 4.2 installed. I thought iOS simulator was bundled with Xcode.
Comment: not exactly a duplicate, but the location is covered here [iOS Simulator Hidden in Xcode 4.3.1?](http://apple.stackexchange.com/questions/43309/ios-simulator-hidden-in-xcode-4-3-1)
Answer: Open your project in XCode. Click the Run button in the upper-left hand corner of the window.
Note that you can chose which iOS device to simulate as just to the right of that button.
If you would like just the iOS simulator, you can open XCode, create an iOS app from a template, run the app, then, with the simulator running, pin it to your dock.
The app itself appears to be in
<code>/Applications/Xcode/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Applications/iOS Simulator
</code>
Comment: this doesn't do anything. I don't have a project to run either. I am just trying to run the simulator which I can run from spotlight on my other mac.
Comment: @AndersKitson see my edit

I am trying to run the iOS simulator


No gradient problem when modifying model's weights with pytorch

Question: When I was trying to add a perturbation to a model and optimize the perturbation itself but not the model parameters. I did like the following, which is very simple:
import torch
import torch.nn as nn
import torch.optim as optim

# Define a simple model
class SimpleModel(nn.Module):
    def __init__(self):
        super(SimpleModel, self).__init__()
        self.linear = nn.Linear(1, 1)

    def forward(self, x, perturbation, clean):
        self.linear.weight.data = perturbation + clean
        return self.linear(x)

# Generate clean dataset
X = torch.tensor([[1.0], [2.0], [3.0], [4.0]], dtype=torch.float32)
Y = 2 * X

# Create the model
model = SimpleModel()

# Define perturbation as a separate parameter
perturbation = torch.tensor(0.1, requires_grad=True)
clean = model.linear.weight.data
# Train the model and optimize the perturbation
criterion = nn.MSELoss()
optimizer_perturbation = optim.SGD([perturbation], lr=0.01)  # Optimize the perturbation

for epoch in range(100):
    optimizer_perturbation.zero_grad()

    outputs = model(X,clean,perturbation)
    loss = criterion(outputs, Y)
    loss.backward()
    # Update the perturbation
    optimizer_perturbation.step()

However, the gradient of perturbation was still None after executing loss.backward(). I cannot figure out why. What caused this problem and what should I do to realize the result I needed?
I think perturbation.grad shouldn't be None after executing loss.backward() but it was.
#before executing loss.backward()
model.linear.weight.grad
None
perturbation.grad
None
#after executing loss.backward()
perturbation.grad
None
model.linear.weight.grad
tensor([[-26.8524]])

Answer: Changing the .data attribute isn't tracked by autograd. You need something like return nn.functional.linear(x, perturbation + clean)
Comment: Yeah, it really helps! But it means I need to reconstruct all the layers' forward function if I need to use a bigger model. That may not be suitable in the practical situations. Waiting for better answers.
Comment: I found it's not complicated at all, at least for DNN and CNN


Do good tires lessen the chances of your innertube bursting?

Question: I have only bought my bike for a month and a half and within this time span, my innertube actually burst 4 times. The bike itself is relatively cheap so I doubt that the tires are of good quality.
I am currently considering changing my tires to better ones so as to not waste money on tubes anymore, but do tires really lessen the chances of my innertubes bursting/puncturing?
Comment: An innertube of even mediocre quality does not "just burst".  There must be a "discontinuity" in the "envelope" around it (the rim and tire) that leaves a bit of the tube without support such that it balloons out.  Sometimes this is a missing rim strip, sometimes it's a hole in the tire, sometimes it's the tire slipping off the rim.
Comment: And as Carson's question suggests, where on the tube the "burst" occurs can tell you a lot.  If it's on the part that presses against the rim them likely there's a hole in your rim strip (or the rim strip is missing entirely).  If it's in the area of the tread then likely there's a hole (cut) in the tire.  If the tube bursts near the junction between rim and tire then it's likely that the tire is slipping off the rim.
Comment: Where on the inner tube was the burst?
Comment: I had a wheel, where the tube was stretching on the 2 nipples near the valve (1 each side) and bursting (there was an isolierband on them). Tried to shape them, but it didn't help...
Answer: Its extremely unlikely for an inner tube to just burst.
It sounds like you are suffering from punctures.
There are two types of puncture; the first is an object penetrating the tire and inner tube, and the second is a 'pinch' puncture where an impact causes the inner tube to be pinched between the tire and rim.
Many bikes (even expensive ones) come with poor quality tires as standard, and yes, changing them can make a big difference to penetration punctures.
No tire is 100% puncture proof, but something like a Schwalbe Marathon Plus is very close, but is heavy and can give a harsh ride.
Continental Gatorskins are favored by many as a good compromise between puncture resistance, rolling speed and comfort.
Pinch punctures are usually caused by hitting an object (such as a pothole) with too little pressure in the tire.  Adding more air to the tire (don't go over the maximum limit) usually prevents these.
Comment: There's a third type of puncture.  One that is caused by some sharp object inside the rim.  Spoke nipples or the valve stem hole may have a rough spot that's puncturing the tube.  Inspecting the punctured tubes will help determine if this is the cause.   If they all have punctures in the same place, and that puncture is on the inside of the tube (closest to the rim), that's likely your cause.
Comment: Good catch, i've never had one of these so didn't think of it.
Comment: fwiw, I don't think you need to go all out and get Gatorskins or Marathon Plus. Sure, they'll protect against punctures, but they are also heavy and provide a harsh ride. I was due for new tires and decided to splurge on Continental GP4000S II, and I haven't had any punctures in the 2 months I've had them. They provide good protection while still being light and giving a good ride. I think that most high quality tires that aren't made super thin for racing will give decent puncture protection. The cheap ones and the stock ones from BSOs are the ones to watch out for.
Comment: Depends where you ride - if there are road hazards, I'd rather just keep a tougher tire.
Answer: Yes, absolutely. Spend an extra 20 dollars on good tires and you could save yourself 30 dollars worth of tubes. Plan on spending somewhere around 40 to 50 dollars a tire. Even if tubes were free, the money is worth saving the hours spent on the side of the road dealing with flats. Look for tires in the 'training' or 'commuting' category, for extra puncture protection.
It should go without saying, take care to stay within the rated PSI of the tire when pumping it up.
http://www.biketiresdirect.com/product/continental-gatorskin-700c-road-tire
Answer: Yes, better tires can help prevent punctures. It has already been mentioned that there are tires specifically made to enhance puncture resistance. One thing that has not been mentioned is that better tires also have stronger sidewalls to offer more tire support when going over bumps and thus better protect against pinch flats. (Once, I had a cheap tire with flimsy sidewalls on my back wheel for use on a stationary trainer. I took it out on a road ride properly inflated and got a pinch flat on the first bump I hit.)
A few tips whether you replace your tires or not:

Keep proper air pressure to avoid pinch flats (i.e., the tire
pinching the tube against the rim when hitting a pothole, curb,
etc)
If you are getting repeated flats, make sure nothing is
lodged in your tire. A piece of glass or wire that is stuck in the
tire will puncture every tube you install until you find and
remove it.
Avoid debris on the roadways. A lot of people ride in a straight path
over everything they encounter on the road (rocks, pebbles, broken
bottles). Steer around these things.
Keep proper air pressure. I know I said that once already. It can't be said enough.
Comment: Someone on this site once joked that people with Marathon Plus tires make a point of steering through debris, because (or as if) they can.
Answer: If the tube leaks out from under the wire bead it will burst.
If you had a cheap tire with a stretched bead that can happen.
If it is real easy to slide the tire on the rim that is a bad sign.
If that was how the burst happened then a new tire would help.
This can happen on even a good new tires if you over inflate too far.
If it bursts again the you need to look at the rims.
See hook bead on this page bicycle tire
Answer: By the term bursting "Inner tube bursting" is not caused by the tire but is caused by over inflating.
Please get a good quality rubber tube(rubber doesn't change its color when tube is inflated )
Yeah and also a combination of a good tube and tires significantly reduces the risk of flats(especially on a road bike) -I have got a set of tire liners and an extra layer of rim tapes as a precaution and until date it seems to be going great!! :)
Comment: Over-inflation must be quite extreme to cause "inner tube bursting", and when it occurs the tire will fail in a quite obvious fashion -- either split open or pop off the rim.


Sent iMessages never get delivered

Question: I have an iPad 2 and something weird is happening with iMessage. I can send messages to my friends, but sometimes after I send the messages it doesn't say delivered at the bottom and my friend says she didn't get the message. She's moving to Hong Kong and I want to keep in touch but all she has is an iPad mini. I'm not even sure if she gets my FaceTime either.
Comment: Is it random iMessage sending failure or can you not get anything through? Also, can she receive other's iMessages?
Answer: iCloud is having some iMessage issues as of late. I've had the same problem. It does eventually work itself out as Apple is aware and addressing it. However, at the moment they're stating all their services are up.
check here if you're curious
https://www.apple.com/support/systemstatus/
I disabled iMessage/iCloud on all my devices (and my fiancé's [compare to you and your friend]) and then re enabled and it started working again. Have you tried that yet?

Sent iMessages never get delivered


In itunes, how do I view entire album of currently playing song?

Question: If I have a playlist of songs, and I want to go from a song and play the entire album, I can't see anyway to do this except manually finding album in music list.  There must be a better way.  This is using itunes 10
Answer: If you normally sort your overall library by album, you can right click on the currently playing song in a playlist and select Show In Playlist -> Music. This will take you directly to that song in your music library.
Answer: If you don't have the little arrows visible, perhaps with the new version of iTunes + Ping, you can make them re-appear:
defaults write com.apple.iTunes show-store-link-arrows 1

If you Option + click on the arrow for an album, you'll see all songs in that album. The arrow next to the artist name to links to all songs by that artist. If you don't want to press Option then you can run this command:
defaults write com.apple.iTunes invertStoreLinks -bool YES

And the normal behavior will be to show you your songs, and the meta behavior will be to link into the iTunes Store.
Comment: if you click on the arrow for an album, you'll see all songs in that album while hold Option it brings you all artist's song not all of you album song! at least it works like this for me.


Convert point layer to text in v8 design file

Question: I have a shape file point layer with field  "name" having attribute values e.g. 'city name'. I want these attribute values as text in v8 design file using FME.
Any help please.
Answer: The simplest solution is to use the LabelPointReplacer transformer, using the name field as the attribute to use to define the label.
Then writing it to DGN should give you text.
You can use the attribute idgs_justification to specify the text justification - i.e. where the text is positioned in relation to the original point. Either the Readers/Writers manual or this article on the FME Knowledgebase shows what values to use (for example 7 is centre/centre, 2 is bottom-left).
If it's multi-line text and you want text nodes then that would be more complicated. Each line of text would need to go into a separate list entry. This article gives a good example of how to do that.


Patch 8788 - Average Time to Deploy

Question: What is a reasonable amount of time to expect for the proper live deployment of a patch including testing on a dev site assuming there are no conflicts?
Comment: Every patch has a different scope, and every environment requires a different set of tests. If i'm reading your question properly, as in "how long does it take to test patch changes", its not possible to answer. If you're just asking how long it takes to run the patch, then the answer is under 1 minute.
Answer: Not really at technical question with a definite answer, but it's entirely dependent on how custom your magento build is. It sounds like your developer needs to be a bit more clear with you as to what is taking so long.
There are a bunch of things that can stop a patch from applying successfully (read: Security Patch SUPEE-8788 - Possible Problems?), these can be conflicting old patches, local overrides to core code, rewrites of core files, overrides of core templates, and anything you can really imagine.
Even if a patch successfully applies you have to go through the patch file-by-file and look for things which may extend a patched file so that they are compatible with the new changes. I've seen classes extend a class which extended a class which was patched, thus causing a breakage in a custom uploader from SUPEE-8788.
In short, there's a bunch of different ways of rewriting and modifying magneto1 that makes it difficult to verify that a patch is installed correctly. You can spend a lot of time and gain a lot of confidence by validating each file in the patch is not affected by

Local overrides (check app/code/community, app/code/local, etc)
Magento rewrites
Theme overrides (check all fallbacks, particularly needed for things with form keys. Don't forget to check mobile if you have a different theme for that!)
Classes extending a patched file. This can be nearly impossible if the patched file is core, but can be easily gauged for classes like the recent uploader changes. Or the changes in the previous patch to Mage_Core_Model_Config which invalidated the Bronto modules config tester validator thing.

That's just assuming that its "your code" you're dealing with, that's not even mentioning community modules which have varying degrees of all the above.

You installed a community module like Pimgento? Welp, you've gotta wait for them to patch their code.
You installed an old unsupported community module? You're on your own.
You installed a module encrypted with ioncube etc? May god have mercy on your soul.

You can spend as long as you need, a lot of the sites that say "We can install SUPEE-8788 in 30 minutes" may be telling the truth for your particular instance, but if your instance is heavily custom then that patch will go live and you'll have problems with the uploader or any other areas of the site patched by 8788, then you'll be going back to them pressuring them for urgent fixes.
How long is a piece of string? In my opinion, 3 or 4 days full time should let someone go in with reasonable confidence that your site will continue to function without issue. Add an extra day for each new frontend theme if there's formkeys and varnish caching to play with.
Or, if your site is vanilla, you can just run your patch and hope magento hasn't introduced any regressions.
¯\_(ツ)_/¯

Patch 8788 - Average Time to Deploy