How do foundries prevent zinc from boiling away when alloyed with Aluminum?

Question: How do foundries prevent lower boiling point metals such as zinc from boiling away when alloyed in a furnace with higher boiling point metals such as aluminum?
Answer: When alloys are made by mixing molten metals (actually an alloy only need contain one metal and at least one other compound, metal or not) the metals only need to be heated to their melting point, not all the way to their boiling point. In the example you've given, the melting point of aluminum is $\pu{660^oC}$, which is $\pu{247^oC}$ below the boiling point of zinc, so the volatilization of zinc is negligible under these conditions.
However, the issue you bring up does present problems in other cases. For example this article states the following:

One difficulty in making alloys is that metals have different melting points. Thus copper melts at $\pu{1,083^oC}$, while zinc melts at $\pu{419^oC}$ and boils at $\pu{907^oC}$. So, in making brass, if we just put pieces of copper and zinc in a crucible and heated them above $\pu{1,083^oC}$, both the metals would certainly melt. But at that high temperature the liquid zinc would also boil away and the vapour would oxidize in the air. The method adopted in this case is to heat first the metal having the higher melting point, namely the copper. When this is molten, the solid zinc is added and is quickly dissolved in the liquid copper before very much zinc has boiled away. Even so, in the making of brass, allowance has to be made for unavoidable zinc loss which amounts to about one part in twenty of the zinc. Consequently, in weighing out the metals previous to alloying, an extra quantity of zinc has to be added.

Summary, TL;DR:
In your example of aluminum and zinc, each metal melts well below either of their boiling points so that loss via volatilization is not a problem. There are cases however, such as alloying copper and zinc, where the boiling point of one metal is lower than the melting point of the other. One way to minimize (but not eliminate) the loss of the more volatile metal is to quickly dissolve it in the high-melting metal and then cool the solution. Although this does not eliminate losses due to volatilization, it can greatly reduce the problem. And actually, since alloys are frequently composed of predominantly one metal, it is not uncommon to dissolve the lesser components into the primary component as a matter of practice anyway.
I hope the example I gave addresses your question. Please don't hesitate to ask for any clarifications in the comments below.
Comment: I assume you then have to process the (e.g.) brass alloy melt relatively quickly, to avoid continuous further loss of zinc?
Comment: @hBy2Py , yes, I'm actually impressed that they keep the losses of Zn so low (~5%, see above). I assume the addition of Zn would be about the last step of the process before cooling it down. There is probably some decrease in the vapor pressure of Zn due to solvation, but don't quote me on that.
Comment: , I also would assume the Zn vapor pressure is lower in Cu solution... but it's by no means certain!
Answer: In the real world zinc losses from brass are kept very minor by keeping temperature below the boiling point of Zn and fluxes added to make a covering of slag. When a founder screws-up and over heats a furnace it makes a " zinc boil" , it produces an exceptionally dense white "fog" of zinc oxide. I will admit to having done it once. In steel the Zn, Pb, etc. are deliberately vaporized (and collected in bag houses)  to clean the steel.
Comment: This reminds me of recycling  , at one time ( and maybe today) ; Die cast scrape was melted on one furnace hearth . Liquid would run down to a lower furnace through an air trap ( like a plumbers "P" trap ). The second furnace is enclosed and hotter, above the boiling point for zinc. Relatively pure zine is distilled and condensed .  On about a monthly basis the  residual from the second furnace is drained; it was lead, zinc , copper, etc.   and could be used at a brass/bronze smelter.


How can I enable the Insert button in Google Chrome?

Question: When I used to press the Insert in internet explorer, I was able to "type over" text.  In Google Chrome it seems the Insert has no effect.  How do I give it an effect (enable me to type-over text)?
Answer: You can't. A bug has been reported on Sept 26, 2011 and yet to be fixed. You can add your vote at http://code.google.com/p/chromium/issues/detail?id=98023
Answer: You can edit the text on a page by using right-clicking on the text, choosing "Inspect Element", find the text in the "Elements" page and double clicking on it. This will allow you to edit it and your changes will be reflected in the browser window. (Bear in mind that your changes are only temporary and will be long once you reload the page).
Comment: This doesn't seem to answer the question at all, please reread the question.


What's the difference between an Epi Junior and a Junior Special?

Question: I was recently gifted a very gently used Epiphone Junior, and was wondering  what the difference is between that and a Junior Special.  Just curious, is all.
Answer: I looked through my old Epiphone catalogue and checked the web site and I didn't find any model of the Junior other than the standard. The Les Paul Special was a popular model, so people selling the Junior may mistakenly be adding the word Special to the description, or calling it the Junior Special to indicate what model it is patterned after.
If there is a version that you have found that includes the word "special" on the head stock instead of just "Junior Model", it is possible that it is from a short run of the model. Occasionally a manufacturer will put out a short run that is for specific promotional events, or to introduce a special or new component such as a different Humbucker, electronics or finish.


Scheduling event based on an index date

Question: Our data load occurs on the 3rd Monday of the month. I want to schedule related pre and post activities (e.g., 5 days prior or 2 days after). Can I schedule using an index date (i.e., 3rd Monday, in this case) such as 3rd Monday - 5 days? Using the weekly designation works for some months but you have to manually fix it for others. Thanks.
Answer: You can use this formula for finding the 3rd Monday of the month (based on your task "Start Date" - or substitute some similar date column name):
 =DATE(YEAR([Start Date]),MONTH([Start Date]),(3*7)+1)-WEEKDAY(DATE(YEAR([Start Date]),MONTH([Start Date]),8-2))

Note that the "3" in (3*7)+1 denotes "3rd" and "Monday" is represented as "2" (as it's the second day of the week) in this part 8-2.
From there, you can create other calculated columns and use the value derived in the calculated column above to determine the dates 5 days prior and 2 days after etc.
If you need more help, let me know.

Scheduling event based on an index date


What is causing black leaves on my Aloe Vera plant?

Question: This was a perfect plant. This started happening a week ago. All the leaves have gone from bright green to black. Some of the leaves are mushy.

I water this plant once a month.
Answer: your plant can't get water from anywhere. give it water more regularly, and put wood chips under it. then it will send a long tap root down into the soil.
This is a very accurate description of what i think the problem is: https://www.ted.com/talks/allan_savory_how_to_green_the_world_s_deserts_and_reverse_climate_change
it also looks like people have been stepping all over it, and crushing the leaves.
Comment: I thought same, so I watered this 3 days ago and the problem only worsened. Then I thought this is due to over-watering, so I haven't watered it till now.
Comment: Was this plant growing well in that pot in that location prior to this? Or was it recently moved/repotted. And where are you located geographically. The only viable-looking piece I can see is the one in the bottom right.
Answer: If the leaves went mushy, then you have a one of two things that happened.  One is over-watering.  The other is a cold snap.  If its a short cold snap the roots will still be alive, but the top will be mushy.
I am guessing its a case of over-watering or poor drainage.  I believe you did not no over-water, but gave the plant poor drainage to start.  When planting aloes you want at least 50% drainage matter, e.g.; gravel, perlite, pumice, lava rock, etc..., but you are much better off with 75-80% drainage to 25% brown matter (water holding). Without the right amount of drainage matter in any potted plant the brown matter can hold water for weeks without drying out.
It is also important to make sure you DO NOT put a layer of rock in the bottom of the pot.  The same potting mix should be from the top to the bottom of the pot.  This is help with drainage.
If you are unsure if your plant needs water use a bamboo skewer or chop stick.  Insert it in the soil for 30 mins or longer.  Then pull it out and check it.  Look at it and touch it.  You should be able to tell if there is still lots of moisture in the soil.


How do to keep programs updated

Question: We all know we should keep our programs up to date, after all each of them could have an unlatched security hole that was fixed in the latest update. However the average computer easily contains 200+ programs and only few of them actually contain automatic updaters. This leaves most of them open to all kinds of attacks. So ho do you deal with this? How do you keep all your programs up to date?
Comment: I'm really tempted to say "Don't use OSes and apps that are stupid enough not to centralise and automate app updates". There's no silver bullet: either it's made convenient for you or you have to manually do it.
Answer:
apt-get update
apt-get upgrade

If you are on Windows or OSX just enable "check for updates" in any important programs. All the ones I use have that option. Also, you don't need to update those "200" programs. I would say update any text editors, PDF viewers, antivirus etc. Some antivirus clients can alert you to updates to some programs as well.
Check out this article for other suggestions. http://lifehacker.com/5384140/five-best-software-update-tools
Comment: No dilemma - solution above - install a better OS :)
Comment: Your "etc" defeats your answer. Would it not be better to upgrade everything? How do you determine the "important programs" or what the "etc." should include? Although the first part of your answer is the answer for Linux, the rest is very "hand-wavy" and not helpful.
Comment: I'm sorry, I was just trying to be helpful. Since there is no unified way to update everything in Windows or OSX.
Comment: But your dilemma highlights the opportunity. How DOES one update software that does not have active updating in Windows? There are ways to do it.
Answer: I believe that ultimately you need to resort to the vendor informing you as to when there are updates to be installed, which might arrive in a variety of ways.

Notification of an automated update via the application itself
Twitter / RSS feeds
Newsletters / E-mail campaigns

Now with that said, I would almost always prefer an automated approach for a personal user. This means using things like Automatic Updates for Windows / OSX and allowing your applications to update automatically. Personally, this is how I keep my stuff up-to-date and I believe I have been very successful in thwarting malicious software from executing on my system. This also comes part-in-parcel with being an educated user, which allows me to spot threats.

"However the average computer easily contains 200+ programs and only
  few of them actually contain automatic updaters"

While this statement might be true, I think it could be argued that you really need to focus on a select few that act as common attack vectors. I have found that doing the following has a great track record of keeping computers clean.

Educate users on how to spot threats
Allow automatic updates to install for your OS
Ensure common attack vectors are patched asap - includes Flash, Adobe Reader / Foxit, Web Browsers, MS Office
Allow your Anti-Virus agent to automatically update itself
Unless you absolutely need it, remove Java (note that a common misconception is you need Java installed for JavaScript to run - this is not true)

In a production environment you'd want to ensure you tested your patches before deploying company wide. For this you could WSUS / SCCM / GPO to deploy patches and software to your machines, however this often involves keeping an eye on when patches are released. I make a point of frequently checking with vendors to see when patches are updated. It might sound tedious to some, however it's much quicker than NIFO'ing a machine.
Answer: chubby_monkey posted a good answer for updating the programs.
You can also write scripts for each program, such as a curl script that checks the website and a regex parser to determine if there's an update. Then, if the download location or link is consistent enough, it can download and install the update automatically. Otherwise, it can notify you.

How do to keep programs updated


Is there a name for the pair (c, R), where c is the stoichiometric coefficient of a reactant R in some chemical reaction?

Question: I am programming a simulation, and I need a good name for a data structure that stores pairs $(c, R)$, where $c$ is the stoichiometric coefficient of a reactant $R$ in some chemical reaction. Is there a name for these pairs $(c, R)$ in chemistry?
Answer: In chemistry, often quantities get denoted by an index $i$, which then stands for some compound ($i=\text{A, B, C, ...}$).
Examples:

The stoichiometric coefficient $\nu_i$
The concentration $c_i$
The amount of substance $n_i$

The notion of grouping together the stoichiometric coefficient with the substance it uses is a novel one for me, and will most likely not have a name.
I suggest you use a name such as "coefpair" or the like and document your code accordingly.


Does Monero still use chacha for wallet encryption?

Question: With the advent of RandomX has Monero created an encryption scheme that use it for key derivation? Also how does/did chacha8 work is there a whitepaper one can read?
Answer: The wallet cache uses chacha20 for cache encryption. The KDF used is still the original Cryptonight (one round by default, overridable with --kdf-rounds).


What are some good Kubernetes training courses?

Question: I'm looking for Kubernetes training online or in person. What are some good training courses to take?
Comment: I would expect in this question to do a basic google search and explain why none of the links in the first 3 pages did not work for you. That would get people some idea how to focus the answers.
Answer: To understand kubernetes internal, it's good to have good understanding of containers, docker, etc.
Here, is the list of useful docker and kubernetes resources:
1) Play with Docker Classroom https://training.play-with-docker.com/
2) Docker Interactive Tutorials https://www.katacoda.com/
3) Play with Docker (PWD) https://labs.play-with-docker.com/
    Play with Kubernetes(PWK) https://labs.play-with-k8s.com/
4) Introduction to Kubernetes course on edX also his company, CloudYuga is a certified Kubernetes service provider and training partner
5) Blog by Docker Captain, https://collabnix.com/
    Also, search kubenetes blogs on Medium which are very useful.
6) Kubernetes The Hard Way github repo by Kelsey hightower updated with latest kubernetes 1.12.0 version.
Hope this helps.


Should you seal grout when using RedGard Backing?

Question: I did a shower in Hardieboard sealed with two layers of Redgard. Should I still seal the grout lines even though we used Redgard underneath?
Comment: I always seal grout so it will be less likely to get stained. Redgard is good but make it bullet proof by sealing the grout.
Answer: You don't have to.  It is completely up to you.  Sealing the grout is doing absolutely nothing as far as water-proofing your current setup.  I Redgard/HB many showers/tubs and here is what I do:

unsanded - gets sealant.  In my opinion it stains easily, especially below level where water constantly hits.
sanded - don't seal it.  It looks better unsealed and this grout allows you to "sand" out a stain.
epoxy - no sealant of course.
Comment: @JimmyFix-it - exactly.  Using grout sealer used to be more important as a lot of installs weren't done water tight.  Even HB without redgard if done right it would be really really hard to leak.  Add on an 1/8" of rubber and we can move past sealer as a water barrier.  I know it works if applied right and applied every x amount of months/years... but that never happens right.
Comment: Agree, one should not count on grout sealer as any form of waterproofing. The "sealant" referred to in other answer for CBP warranty is **not** the grout sealer.
Comment: @JimmyFix-it - if you can't count on it to prevent stains how can it really be sealing water...   He has HB/Redgard... if there is water getting in bad places he has bigger problems.
Comment: Yes, but his question relates the use of grout sealer to his application of Redguard, implying some sort of waterproofing value to the grout sealer, which is not correct. It should never be relied on for that purpose, even though it may give some stain resistance.
Comment: @JimmyFix-it - Then what are they referring to? Sealer is to prevent stains. I'll have to admit, I kinda stopped reading after *Should I seal grout*. I don't care what comes after that, my answer is yes. - Is it harder to sand out stains on sealed sanded grout then non-sealed, DMoore?
Answer: I always seal the grout, whether or not I'm after one of Custom Building Products' warranties:

A complete CUSTOM Shower Installation System of products must be used
  including Shower Slope, Shower Base, ANSI A118.4 Bedding Mortar, Sealant, and suitable CUSTOM RedGard Waterproofing and Crack Prevention Membrane to qualify for this limited warranty. –CBP

(I've no affiliation with CBP. If other companies offer similar warranties, I'd love to know about them.)


Can 2300 watt washing machine burn out wiring in my house?

Question: My standard voltage is 230 V and the socket is 16 A. I am asking the question because I had a 1500 watt water heating rod connected with another 15A socket which did burn out my home wires after a week of use.
Comment: What does "burn out" mean? If your home is fitted with proper circuit breakers or fuses the wiring is protected. Please revise to explain better what your specific concern is and to tell us about your wiring.
Comment: Can you provide photos of the burnout you had with the 1500W water heater? That should be *well* within the capability of a 16A/230V socket
Comment: @isherwood, When I was using the 1500 watt heating rod, I just heard some small sound of wire or socket blast from inside. I think either my socket was blown out or the wires that were connected to that socket burned out.
Answer: Your socket and wiring (if properly installed/rated) are good for 3,680 Watts (230V X 16A.) As such a 2300W device should be perfectly fine.
However:
If a 1500W device "burned out the wires" on a 15A 230V (3,450W) socket, either the wiring in question was improper/defective, or there were other things also connected to those wires. In any case, somehting was wrong if the wires burned out rather than a circuit breaker (or fuse) tripping (or blowing.)
So your wiring installation may be improper or defective - it is at least suspect, and should be checked by a qualified electrician to identify and correct any dangerous deficiencies.
Answer: Yes, easily if the house wiring is faulty or defective.
Get it all checked by a competant registered electrician.


ATOM feed + Google Analytics Javascript = validation?

Question: Would it be possible to stick my Google Analytics Javascript slug into my ATOM feed and still have it validate? I don't want to feedburn my feed, but would like the demographic info GA provides.
Answer: No it wouldn't because ATOM readers don't run javascript. So the GA snippet won't run.
You have to use other ways to find out how many people really download your atom feeds. And then there's a bigger problem that most people will read your feeds through Google Reader or some kind of web reader. That means people won't be downloading your feed, but the webreader will on server side. So it gets even more complicated. Besides tracking how many people download your feeds you have to use Google Reader API to get the number of subscribers. For that reason feedburner is still your best friend when you want feed analytics.
If you really want to track feed usage and don't want feedburner you could provide ATOM feeds with only a small part of your content and a link to your website to read the whole content. Then you track people on your site analytics.


How do empiricism, pragmatism and nominalism fit into one another?

Question: How do the previously mentioned schools or methods fit into one another? Is nominalism a type of pragmatism? Is pragmatism always a form of empiricism etc.
Comment: Can you expand a little bit the question ? Put in this "oracolar" form, the possible answers will be only a collection of **NO**.
Comment: So I know that radical empiricism was a view proposed by William James that supposes that experience rests on nothing outside of itself. Additionally I know that nominalists reject universals and state that variability exists within concepts the concepts usually described as universal such as "the truth" or "reality". Is there a link between nominalist approaches to naming convention which is at work when a pragmatist uses terms to make distinctions?
Answer: Pragmatism, Empiricism and Nominalism are different positions, that are each best understood as responding to quite different kinds of questions.

Nominalism is a metaphysical view about what kinds of things exist. According to nominalists the only things that exist are particular individuals, like Socrates. On this view although we can talk about abstract, universal ideas like "humanity" it is really only particular humans, for instance, that exist.
Empiricism is an epistemological view about how we know things. Specifically empiricists believe that all of our knowledge is acquired through sensation.
Although this is somewhat controversial, I think it's best to understand pragmatism as a view about truth. Namely, a pragmatist is a person who believes a sentence is true if and only if it is what we would all agree to, at the ultimate end of inquiry. That is, the truths are the things we'll believe when all the evidence is in, as it were.

Now how are these three positions related? Well, to my knowledge every single pragmatist is also an empiricist, although the converse doesn't hold. Nominalists tend to be empiricists and vice versa, because one of the reasons to be suspicious of universals, as nominalists are, is that it's hard to make sense of how we could ever come to know them, given that we don't experience them. Pragmatists, I would suppose, would tend to be nominalists too, since they're all empiricists, but I wouldn't be surprised if some pragmatists denied nominalism. (All you have to think is that all the evidence isn't in yet about whether we need numbers to be real for science to work, for instance.)
Comment: +1. Of course pragmatists are so-far removed from the debate in which "nominalism" is involved that they may not even know they are nominalists.
Answer: Actually, James makes the connection between pragmatism and nominalism himself. He says in the second chapter:
THEORIES THUS BECOME INSTRUMENTS, NOT ANSWERS TO ENIGMAS, IN WHICH WE CAN REST. We don't lie back upon them, we move forward, and, on occasion, make nature over again by their aid. Pragmatism unstiffens all our theories, limbers them up and sets each one at work. Being nothing essentially new, it harmonizes with many ancient philosophic tendencies. It agrees with nominalism for instance, in always appealing to particulars; with utilitarianism in emphasizing practical aspects; with positivism in its disdain for verbal solutions, useless questions, and metaphysical abstractions.


Does Mediawiki encrypt logins by default as the browser sends them to the server?

Question: Several searches only turned up questions about encrypting login info on the server side. Does Mediawiki encrypt logins after you type them in the browser and send them? (to prevent a man-in-the-middle from reading them in transit and taking over an account)
Answer: Nope, they're submitted as clear form data on the POST request. You definitely need SSL on your login page.
Answer: No serious web application encrypts logins on the server side. At most it would give you an illusion of safety, as opposed to the real safety provided by HTTPS. If the web traffic is unencrypted, the attacker can arbitrarily alter the data you send or receive (for example, inject malicious Javascript that logs the password as you type it; or wait until you log in and then copy your cookies and issue commands in your name).


How do I find Gigantimax Pokemon?

Question: Gigantimax Pokemon are pretty cool, and can be useful in battles. But the problem is, sometimes I catch them and send them to boxes, where I may forget them until I search for that specific Gigantimax Pokemon again later. After that, I may forget which pokemon are Gigantimax, and which aren't. Is there a way to have a filter that shows me all the Gigantimax Pokemon that I have?
Answer: As Wondercricket said in his answer there is no built-in way to recognize a Gigantimax  Pokemon from a regular one without checking its summary.
That said, what is worth mentioning is that marks that you apply on a Pokemon are visible while scrolling the box list.
This means that you can use marks to create your very own categorization system. While in the Sun/Moon era this was used mostly to mark perfect IV in a specific stat, now they are more often used to mark other things (since the judge feature kinda eliminates the need for specific IV markers).
For example, take in consideration this (obviously unofficial) table created by a Youtube user (link below) with some suggestions:

(source here,  )
Obviously this is not a full solution but could help you to avoid the need to check the summary every time.
Answer: There is unfortunately (as far as I can remember), no filter option to search your boxes for Pokémon that can Gigantimax. You can, however, determine if a Pokemon can Gigantimax by viewing the summary details. If it can, there will be a large X-like symbol next to it's name.

Image Source

How do I find Gigantimax Pokemon?


Example of decentralized access control?

Question: Classical server-client architectures implement classical centralised access-control. The problem with that is that administrator with root access has full control over it what may represent unacceptable risk in some scenarios.
There are multiple decentralised systems that do not have root administrators - like BitTorrent or Bitcoin (or Ethereum). However, none of them seem to have access control functionality in them. Are there systems that do (but are decentralised)?
Comment: You've named one example yourself. Bitcoin has access control. If it didn't anybody could access your wallet and take all your money. It's also decentralized in that you can create transactions from your wallet from anywhere in the world only by knowing your private key. Anybody you give your private key to also has access to the wallet. It's decentralized, because there is no key escrow service that holds all the private keys of all wallets. Does that make sense? What exactly do you understand by "decentralized access control"?
Comment: Bitcoin is a distributed system, but its access control is not decentralized. There is still the "single" root of trust - owner of the wallet. That owner has unlimited access to what he can do with that. There is no separation of privilege. Decentralized access control would have multiple root of trusts - multiple separate server/admins/users that can grant the access.
Comment: Of course, there is separation of privilege. Anyone who has a wallet can send you some coins, but only the holder of the private key can send coins to others. Multiple admins makes only sense if you want to *revoke* access, but that is an issue with distributed systems that is not solved efficiently and likely not achievable for truly decentralized systems.
Comment: Not only to revoke - but also to restore access. I see no fundamental reason why that can't be done - majority of nodes just need to agree on that. BitCoin can't do that of course - I was wondering about distributed systems that could..
Answer: Use MFA and split the authentication pieces between separate parties or several pieces of information required to generate a hash used as a password.
Someone who wants access requires the two pieces much like two keys to open a single door.
Answer: Firstly, the (partial) answer to the admin problem is Privileged Access Management (PAM). This is typically a bolt-on system that uses higher level processes (perhaps with one or more humans giving authorisation for example) to give temporary privileged access. This is increasingly common and you will certainly find it in use in any global cloud provider.
I'm not so sure about your actual question. I can't think of anything off the top of my head, perhaps others know more.
However, a second possibility that is also increasingly common is to use federated identities. In the past, implementing identity federation was a horribly complex and expensive process. However, with the advent of things like Azure Active Directory and Azure B2B, this is becoming rapidly easier. In this case, you still have central control but of a much smaller "centre" - so, for example, organisations that want to collaborate and share services may confer some level of trust to another organisation.
Answer: What you ask can easily be implemented in Ethereum smart contracts, using modifiers. Basically you can build functions in such a way that they can only be called by given addresses. The allowed addresses could be a variable themselves, which may be changed by a user with even higher privileges (with another function with modifiers).


What permission do I need to build a rocket that goes to space?

Question: I wanted to build a rocket that goes to the karman line at 340000 feet which is technically space. I know the rules and what I need to get to launch the rocket such as faa clearance and more but I wanted to know if there were any certificates or permission I needed to build the rocket itself. I wanted to build one like the traveler 4 rocket as seen here http://www.uscrpl.com/traveler-iv this rocket reached the karman line with a solid rocket engine. I wanted to build something like this with a solid rocket engine. Hope someone can help thanks! EDIT: My location is in ohio, usa
Comment: You might want to include your location as the rules could vary widely.
Answer: You'll need a level 3 certification for high power rocketry in order to get your hands on the stuff you need to build your rocket.  The industry has so far been self-regulating so this isn't an official requirement, but nobody will sell you the engines without it.
I suspect you also need a flight termination system on a rocket that goes that far as I seriously doubt you can ensure the rocket remains over property you have permission to fly over.  That's explosives which would require a blaster's license.
You're also in way beyond your depth, anyone who actually knows enough about rocketry to do this would not have asked the question.
Comment: Linking to reference citations would improve this Answer. For example, did you mean: https://www.nar.org/high-power-rocketry-info/level-3-certification/ ?
Comment: @BasilBourque Yeah--I didn't have the link at hand and since the important part was that he was way beyond his depth I didn't feel the need to hunt it down.
Comment: The links would be for the rest of us uninformed readers who are curious.


AWS/EC2 ubuntu and ssh for users other than ubuntu

Question: Ubuntu on EC2 creates a user ubuntu by default. I can set up SSH keys with PuTTY and login in just fine. I've created two more logins but cannot use same PuTTY configuration to get in.
I've dug around quite a bit and changed /etc/ssh/ssh_config files and restarted but it doesn't seem to help.
I'm guessing anyone else using AWS image may have encountered this same scenario.
Thanks,
Craig
this is ubuntu 3.13.0-48-generic
Answer: There isn't any special ssh elastic cloud compute sauce! Rather, each newly created user needs a separate ssh directory and authorized key file.
First, from you EC2 server, switch to your newly create user account ('foo' in this example):
<code>    su foo
</code>
Next, create an SSH directory for foo and set permissions:
<code>    mkdir .ssh  && chmod 700 .ssh
</code>
Then change into the newly created directory:
<code>    cd .ssh/
</code>
Here's a refresher on generating a private/public key pair on your local machine:
http://www.ece.uci.edu/~chou/ssh-key.html1
Once you have your id_rsa.pub key, you can cat and then copy the key from your local machine to your server:
<code>    echo "paste your_key_here" > ~/.ssh/authorized_keys
</code>
Set permissions on the contents of the directory:
<code>    chmod 600 ~/.ssh/*
</code>
It's not a bad idea to edit the SSH config file as a root user (with vi or your text editor of choice):
<code>sudo vi /etc/ssh/sshd_config
</code>
and add the users ubuntu foo (and any additional users you've created) to the AllowedUsers Field (you may need to create it if it isn't there):
<code>    AllowUsers ubuntu foo
</code>
(write & quit).
Lastly, restart the service:
<code>    service ssh restart
</code>
Test & confirm that you can now log in as user foo.


Canon EOS T2i 35-55 mm lens. Won't autofocus

Question: Actually it WILL autofocus if I force adjust focus by hand beyond subject.  It then adjusts itself to focus.  If the lens is focused in front of the subject, it will not autofocus.  Bad servo in the lens?
Comment: I've never heard of an EOS EF 35-55mm lens. What lens are you actually referring to?
Comment: If you are forcing manual focus on a non *FTM focus* lens when the switch is set to *AF*, you have probably damaged the focus mechanism. Maybe the servo, but more likely the linkage at some point.
Answer: If you think the motor is only working in one direction, you might try to test the theory by focusing in live mode.  If it's like mine, it will usually go back and forth to home in on the sharpest focus (using contrast rather than phase detection), so if the motor is only working in one direction it will probably not be able to focus in live mode.
Of course, if you have any access to a different camera, you could double check it on another camera to make sure the problem is in the lens.  In any case, you'll probably need to send it in for analysis/repair.


Clean classloader from timerTask connectionpool

Question: i have an application with some timertask, connectionPools. I also developpe a classloader and sometime i need to clean the classloader. The problem is that the timer task is like a daemon with refere to a class. How can i cancel the timers from the timertask and how can i close connection pools without calling to the .remove() but using a general solution.
Thanks
Answer: Once you load a class via a classloader, there is no direct method to unload the class from that classloader.
Can you describe the question in more details?


How is adrenaline (also known as "epinephrine") a ligand?

Question: I keep reading that adrenaline is a ligand, however, from what I understand a ligand is a molecule or ion which donates a pair of electrons to a central transition metal ion in a complex. If this is the correct definition of a "ligand", then how can adrenaline be a ligand?
Comment: In biology, ligands are chemicals that attach to receptors on cell membranes, stimulating a cellular response. You're using the definition of a ligand in chemistry. :)
Comment: @lightweaver - that's sufficient for an answer when you include a link to the respective definitions.
Answer: The definition of "ligand" in the question, "a molecule or ion which donates a pair of electrons to a central transition metal ion in a complex" is clearly a more technical 'chemistry-type' of definition. Ligands in biology and medicine can be all sorts of molecules, though most of the time we think of them as molecules that bind to a particular receptor. Those receptors can be ion channels, enzymes, transmembrane receptors at the cell surface or within the cell in an organelle, nuclear proteins that control expression of genes in the cell nucleus (i.e. transcription factors), etc...the list could go on and on... In fact, more recently we have come to appreciate that compounds like bile acids - that were previously thought to be important only in fat absorption in the gastrointestinal/digestive tract - are also ligands for receptors that control gene transcription ("Farnesoid X Receptor") as well as increase energy expenditure in brown adipose tissue and skeletal muscle (through receptors like the "TGR5" receptor).
But... back to the question...
If a molecule binds to a receptor, then it's a ligand for that receptor. The ligand doesn't have to donate any electrons specifically to a transition metal. Most of the time in medicine/biology the binding of a specific ligand to its receptor is a reversible process that is dependent on the concentration of the ligand and the availability of the receptor (among other things). The specificity of ligand for the receptor is due to chemical factors like hydrogen bonding, electrostatic interactions (like positive charges attracting negative charges), as well as other chemical interactions beyond the scope of this question. As you can see from the picture below, the hydroxy groups (-OH) that are part of the serine residues on the receptor are hydrogen bonding with the hydroxy groups on the epinephrine molecule itself. Moreover, the carboxy group (-COOH) on the aspartate residue is binding to the positively charged amino (NH3+) on the epinephrine molecule.


Cave spider trap issues

Question: I have a cave spider spawner and it works great other than the area where I hit them. I've tried several designs but they can still hit me. Does anyone have any idea how to fix this?
This is my current setup:

The spiders climb to the top of that hole where they are crushed down to one hit. The problem is no matter where I am around the hole I get hit and poisoned is there a way I can stop them from hitting me? I need a design that prevents them from hitting me that is my question does anyone have a design?
Comment: can you show us what your setup looks like or something?
Comment: The best way I can describe it is a 2x2 hole with glass panes above it like over each of the different air blocks the hole is 2 blocks deep and spider will go to the top of the hole to be crushed then killed the only problem is when I get close to the glass panes I get hit I don't know why the glass panes stop normal spiders from hitting me but it isn't working with cave spiders I am trying to figure out a design that will prevent the spiders from hitting me.
Comment: which resource pack is that?
Comment: It's on Xbox one and it's the fantasy texture pack in going to try the slap design.
Answer: I have found a design that appears to work you still get hit but it's only if you want to get hit. Meaning if you purposely go into the areas where they can hit you. If you go to this link you can find the video I watched to discover this design. Thank you all for all of the help. Here is the link:
Answer: Try blocking an area so they can't touch you. But at least too be able to attack them. You can use fences for they need to climb a solid block.
Comment: Currently I have a 2x2 hole with glass panes floating over the hole. I know this works with regular spiders ,but it doesn't appear to work with cave spiders. Is what I have anything like what you are describing?
Comment: Spiders climb fences with an Yao Ming face. They climb any block that is solid in collision sense, not opaque in transparency sense. Also, "build something so they can't hit you" does not exactly help someone who asks for a "design that prevents them from hitting me".
Comment: `Spiders climb fences with an Yao Ming face` Um, I'm sure your crazy because I don't know what that is.
Comment: @JimJones So, when you don't know something and can't be bothered to copy it into Google - that means someone is crazy? Also, "you're crazy",  not "your" :-P
Answer: Today I watched this video. now saw your question and took part of that video which was useful
Use half slabs and stairs as shown in this image.
Comment: This design does not work as the spiders can escape in that design....
Comment: Normal Spiders can not fit through 0.5 meter high gap, but Cave Spiders this question is about can.
Comment: cave spiders **Can** go through 0.5 high gap **?**

Cave spider trap issues


Does your imagination become true if you say Inshallah?

Question: We want many things in our life. Sometimes we get what we want and otherwise not. So by saying Inshallah will your wish become true? Does saying Inshallah makes your every wish come true?
Comment: Seeing all your questions are about the same problem of saying wrong things, you should probably be more careful what you say.
Answer: No saying inshallah doesnt mean your wish will come true, the sentece inshallah means if god wills, so maybe god wont will you a specfic thing which you want.
And the reason we say inshallah is so that we dont make false promises like promising someone that you are going to do something but not beign able to do it later and in that case it was gods will to not happen.


Schedule of buses going from Antalya to Kumluka / Kas and back

Question: Can anyone give me an advice about schedule of buses going from Antalya to Kumluka / Kas and back? Especially in December (if it is different in off-season)
Answer: For Kumluca, based on this website, there are a lot of bus firms that you can use from Antalya (or to Antalya). Mostly used ones are Kamil Koç, Metro Turizm and Pamukkale Turizm. I choose one of these if I were you.
For Kaş, based on this website, there are Metro Turizm, Ulusoy Turizm, Kamil Koç and Pamukkale Turizm which I suggest as well.
You can check their websites and see the bus schedules. These schedules usually won't change based on seasons by the way.
Comment: But what city should I search for? There is no Antalya in the selection?!? Anamur, Ankarayol, but nothing else starting with An...
Comment: @IvanGerasimenko On Metro Turizm page, both `Antalya <--> Kumluca` and `Antalya <--> Kaş` options are available as far as I can see. But not for others weirdly. You can still call their call centers (phone numbers which you can take their websites) to get a "better" information for your vacation schedules.
Comment: Antalya is not placed in alphabetic order. It goes first like Istanbul... Thanks
Comment: @IvanGerasimenko Yeah, some websites do that. They list mostly used city names on top of the list instead of alphabetic order. In Turkey, Istanbul, Izmır and Ankara can be examples for this situation.


Keeping an object from gaining or losing altitude

Question: How can I find the thrust, $t$, needed to keep an object with $m$ mass, in the influence of an object with $g$ gravity, from gaining or losing any altitude?
Answer: Forces cause acceleration, or changes in speed. If your speed is constant, the total force on you must be 0.
Gravity is one force acting on you. The force of gravity is equal to your weight. It pulls you down.
To make the total force add up to 0, you need another force equal to your weight in the upward direction. Often this upward force is provided by the floor you are standing on. You could also get it by standing on a rocket. Either way, the same force is needed.
If the total force is 0, your speed will not change. If that speed happens to be 0, you will not gain or lose altitude.
If your mass is $m$, then your weight is $mg$. So the thrust must also be this much. $t = mg$
Answer: Take a simple example of an everyday situation where an object is kept from gaining or losing amplitude: Put the object on a shelf and let it sit there.
Now think about this situation. What is the force applied by the shelf to the object to keep it from gaining or losing amplitude?


reference request for singular Kahler space

Question: Kahler spaces are just certain singular spaces equipped with a Kahler metric in appropriate sense. I first came across it Demaily-Paun's classical paper Numercical Characterization of the Kahler cone of a compact Kahler manifold. However it seems to refer the reader to the relevant background material in another paper of Demaily which is in French. I wonder whether there is any reference that have some background materials on Kahler spaces: definition, fundamental properties etc.
Answer: For a reference  in English, you could take a look at this paper of Varouchas, which contains a definition of Kähler spaces and relatied concepts (e.g. Kähler morphisms) and some of their fundamental properties.
Comment: Thank you very much!
Answer: There is a discussion of this topic in the recent book Cycles analytiques complexes II : l'espace des cycles by Barlet and Magnússon, chapter XII.3. An English translation (to be published by Springer) is forthcoming.
You will also find a short discussion in the book Degenerate Complex Monge–Ampère Equations by Guedj and Zeriahi, chapter 16.3.
Comment: Thank you very much! By the way, since you mentioned Guedj and Zeriahi's book, is there any reference for the materials covered in their chapter 16 besides the standard references for minimal model program. Those seem to require too many prerequisites for differential geometers.


Cometd, jquery and database

Question: I would to retrieve data from DB with cometd and jquery! I can established a connection and making handshake, but I can't understand how to send a calling to a page that retrieve my data from DB. Have you any idea?
Answer: Cometd and jquery don't provide database access.cometD is just scripting and you have to make db connection and getting data and putting on jquery cometD publish() function. That is takes data and put on channel that u make. That's it.
If you have any query then go to www.cometd.org
Answer: Cometd and jquery don't provide database access by themselves. What you need to do is developping a db layer on server side (using JPA if you develop server side in java). Then you need to plug your cometd code (server side) to your db layer.
On the client side, cometdb will receive messages that you will feed in your web pages with jquery for example.
You have some examples on the cometd web site,
Answer: As @unludo already mentioned, CometD and jQuery themselves are not meant to provide any DB access functionality. You will have to implement that on the server-side yourself.
Have a look at the CometD Primer here
http://cometd.org/documentation/howtos/primer
The Maven archetype "cometd-archetype-jquery-jetty7" will generate a Maven project with CometD/Jetty + jQuery that you can immediately run with "mvn jetty:run".
The generated project uses the Spring Framework and therefore you can easily leverage the data access abstractions provided by Spring to implement your DB access requirements.
Have a look at
http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/spring-data-tier.html
Good luck!

Cometd, jquery and database


How do I get my network card's model number without opening my computer box?

Question: How do I get my network card's model number without opening my computer box?
Answer: If in Windows, open device manager and expand Network Adapters.
Answer: Linux:
use the commands lspci,  lspci -v, lshw, lshw -a

Windows:
More detailed informations than the device manager can be provided by some as colled "hardware info" programs.
Une i linke in particular is "Pc Wizard"
http://www.cpuid.com/softwares/pc-wizard.html
Is made from the same producers of the famous Cpu-z(cpu info program)


How to add block to "add/edit" content page?

Question: is there a way to add views block to add/edit content pages? I have two content types and one of them has Taxonomy term baste with unique terms (one term per node), when creating new node I want to have block with unused terms. I tried to accomplish this using Markup module but no success, and Display suite and Panels didn't worked.
Answer: Here's how to display a block on node add/edit pages in Drupal 8:
Go to Structure -> Blocks.  Select the block layout page for the theme you use to add/edit nodes. This is usually the admin theme, but it may also be the standard theme for your site if you want to display the block to non-admin users. If you want to show the block to both admin and non-admin users, you may need to configure the block settings (as described below) for both the admin theme and the standard theme.
On the block layout page, click Edit on the block you want to display.
Under Visibility, click Pages.
In the text field, enter:
/node/add/*
/node/*/edit

For Drupal 7, don't use the first slash:
node/add/*
node/*/edit

The * is a wildcard that says "any content/value can go here."
Then check the radio button for Show for the listed pages.
If you also want to limit the block to only show for certain content types, you can use the Content types option above Pages.
Comment: Might be worth mentioning that you need to do this on the blocks page for the admin theme (most people use admin theme for node add/edit and the block layout defaults to the front end theme)
Comment: @Clive Good point, that's definitely a gotcha.  Updated.
Comment: @PatrickKenny Thank You very very very much, I have created so may sites in Drupal, and never felt so dumb about "problem" like this. This is so simple and clean solution. Thank you once again.


Access Management Containerization

Question: Is it possible to create a docker container for access management instead of using dedicated machines. If possible; please share some references on this.
Comment: How you can configure this is largely general Docker knowledge. Do you have any specific questions?
Answer: That is definitely possible. As a matter of fact, we are using (Alpine Linux based) Docker Containers for both Access Management and Add-ons Service for internal testing purposes and in our RWS Cloud offerings.
Example Dockerfile for Access Management:
<code>FROM mcr.microsoft.com/dotnet/aspnet:6.0-alpine3.16

ARG source
WORKDIR /app
EXPOSE 80
COPY ${source:-obj/Docker/publish} .

RUN apk update && \
    apk upgrade && \
    apk add netcat; \
    apk add icu-libs; \
    apk add icu-data-full; \
    chmod +x ./containerBootstrap.sh

# Disable the invariant mode (set in base image)
ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT=false

ENTRYPOINT ./containerBootstrap.sh
</code>

Access Management Containerization


Orthographies that use diacritics to mark grammatical tone

Question: Are there any orthographies that use diacritics to mark grammatical tone instead of lexical tone? Or a combination of both?
Comment: Hello! Welcome to LSE! On this site, we would prefer that you try finding the answer before asking here
Comment: I don't think there are any orthographies that mark grammatical tone _differently_ from lexical tone. As far as orthography is concerned, tone is tone, regardless of its origin. How would you mark grammatical tone mutations (or just phonetic tone sandhi) on a lexical tone if you write them in separate ways?
Answer: In Lingála, the acute accent is used to mark high tone (and less commonly the grave accent for low tone), whether it's lexical or grammatical.
For example, acute accents mark the difference between násála "I might make it" (subjunctive) and nasálá "I made it and it's over and done" (ultimate). The high tone on the root -sál- "make" is lexical (every root has an inherent high or low tone) but the tones on the prefix and suffix are determined by the tense (/aspect/mood).
(Note that the prefix itself is not part of the tense marking: na- indicates first person singular subject. Only the tone of the prefix is.)


Copy UV scale within one object

Question: This problem has been addressed many times before for copying UV's from one object to another object. But I need to copy UV map scale from one face group to another within the same object. In the example I've a brick texture that I've sized 15 times on X and Y. Now when I apply the same material to the chimney the texture is much smaller because the UV map is smaller. I can scale it by hand in the UV editor, but it will be difficult to hit the same scale factor and it just seems so random to do. Is it possible to just copy the UV scale from the walls? I know it's possible in 3DS Max..
Answer: How we usually go about matching the uv is to scale all the uv which are suppose to have the same materials together after matching the scale with Ctrl+A (Match island scale operation.) If this is impossible in a particular workflow. Then try the following:
We usually end up using a checker map pattern to eyeball the sizes of the checker, to approximate the scale of every surface before applying the actual material.

Create a color checker image go for 2048x2048
Apply the checker to all the surface of the model.
Enter Edit Mode and duplicate the faces in question and move it near the faces that has the scale you want to match. (Step for easier eyeball comparison)
Select the duplicated face in the UV Editor and start scaling.
Match the sizes in the checker pattern, and take note of the scaling factor
on the bottom left hand of the uv scale before hitting LMB .
Delete the duplicated face.
Enter the scale value from step 5. to the faces you want to affect.

If these answers are not satisfactory or understood, will be glad to post some images to help explain the workflow.
Comment: It's my first model in Blender that I'm making after a Youtube tutorial and the author pointed out that it's important to mark seams all the time during the build up process. I did so but when it came to texturing it showed up in the UV editor, that my maps for the building are only partly okay. Only one wall had parallel map edges in the UV editor, the others were somehow bended and upside down etc. Thats why I did a project from view map on each wall individually and a cube projection on the chimney. This is how I ended up in this situation. What should I have done differently?
Comment: Use the method above when you can't get a fluid workflow to keep the scale of all the uv. Very often and in fact most of the time, complex models will end up with various method of unwrapping and have problems with scale. The truth is much later down the road it's a good thing, cause not all texture will appear right with one scale, hence the ability to scale them individually helps. As with seams and marking them. Try to learn how to unwrap simple objects and grasp it's concept. Just like all other things in life , the more you practise the better you get.
Answer: I hate eyeballing stuff.
My situation
I have attached a small face to an already textured object, applied the same material to the new face, ended up with completely misaligned UV-mappings:

The UV-editor:

In my situation modifying the UV-mapping of the original face (and the rest of the object) is not an option.
How-to
I can see that I need to rotate the UV-mapping of the new face by 90°. (In the very first image you can see how the texture of the new face is rotated by 90°.)
And I know the vertical scale can be matched by simply aligning the two vertical edges in the UV-editor.
Let's do that:

NOTE: Because the new face is touching the old one with its right side that's also the side its texture needs to be aligned to.
(By shifting the left edge of the UV-mapping in the UV-Editor along the horizontal axis you will be able to tell which edge is the texture aligned to. If it is not the Right one, rotate its mapping by 180°.)
The rest of the challenge is to "copy" the horizontal scale of the old face to the new one.
To achieve that you need to do following:

Calculate the ratio of widths of both faces: use Measure on both of them -> new_face_width / old_face_width;
apply the width-ratio to the width of the UV-mapping of the new face.

In my case the ratio ended up being 0.04761806754935521746299985989727
To apply the width-ratio you calculated:

Align (only!) the width of the new face's UV-mapping with the width of old face's UV-mapping (use snapping "Snap to vertices" to maintain accuracy):

Apply the width-ratio to the new face's UV-mapping by scaling it along the horizontal axis: by first dragging the red axis of the scaling gizmo (doesn't matter by how much) and then copying the previously calculated number into the Resize dialog. You will end with something like this:

Finalize
Now just move the new face's UV-mapping back to its place (use "Snapping to vertices" again):

The result

Copy UV scale within one object


Thought experiment: if an observer can travel at the speed of light

Question: What would the observer see if he could travel at the speed of light and shot a photon beam at the same time?
Comment: What would the observer see if 3+3=7?
Comment: Also, this has nothing to do with quantum-gravity.
Comment: It does not make sense to ask what the laws of physics say would happen in situations that the laws of physics say can't happen.
Comment: Also, even if you had said, "travel at half the speed of light," those words would have no meaning in the context of your question. Specifically, "speed" doesn't mean anything unless you are describing the _relative motion_ of two or more objects. In the experiment you described, there's just the observer and a laser, and neither one of them is moving relative to the other.
Comment: What exactly cannot happen, an observer traveling at the speed of light?
Answer: Short answer: Nothing
Thoughts experiments like this are always problematic because you violate physics but still want a physical explanation. So we have to make the following assumptions: Somehow, the observer and the light emitting device are all massless.
From special relativity follows, that everything that moves slower than the speed of light will always be slower than the speed of light and everything that moves at the speed of light will always move at the speed of light (unless it ceases to exist).
Imagine that you and your friend are somewhere in empty space and the distance between you is closing. From your perspective, it might very well look like you are standing still and your friend is floating towards you. However, from his perspective it can look the same, i.e. he is standing still, and you are the one floating. There is no way to tell the difference, as long as you both are moving at a constant speed. The perspective where you are standing still is called your rest frame. By means of Lorentz transformations, a slow object can always be transformed into its rest frame. Lorentz transformations do transform not only the spatial coordinates but also time. This leads to an effect called time dilation. The faster an object is going, the slower it experiences time (you might have heard of the https://en.wikipedia.org/wiki/Twin_paradox). One way to understand this, that you always move at the speed of light, but it is divided into time and spatial dimension. The following might be a bit crude, but I hope it helps in illustrating. "If you are standing still in space, all your velocity is used to move you through time. If you now accelerate, you take part of your velocity and move it to the spatial dimension. So you now move less in time and therefore age slower." (You will not notice the difference in your frame though).
That being said: You can not find a rest frame for a light-like particle, such as a photon. All its speed is located in the spatial dimensions. Thus it does not "move through time"), so light like particles do not age.
Thus, the observer would be frozen in time and not able to observe anything.
Comment: That perfectly answers the initial question. The linguistics approach that Im taking from a metaphisical perspective only aims at closing the gap between what is imagined and what is known, in the sense that from a knowledge perspective, solutions are first imagined and only then "materialized" in a corpus cognoscendi frame. Carrying on, please assume that the observers are massless, in a singularity sense and that for light quanta time goes by computationally where each step is performed instantly. Would you then say that instead of nothing, the observers could see everything?


It seems like he has asked her vs. He seems to have asked her

Question: Which one is correct? And if both are, then please explain to me in which situations can I use "seems to have" and what is  the grammar term for it? Thanks in advance.
Answer: Both sentences are grammatically correct.

It seems like he asked her.

This is a comment on the situation as a whole ("it").
"What's going on? Can we go?"
-- "Well, it seems like he asked her, but I'm not sure what's happening."

He seems to have asked her.

This is a comment on the "he".
"What's going on? Can Harry come?"
-- "He seems to have asked her, but I'm not sure if he can come."
The primary difference between these sentences is that the first sentence is about it, whereas the second sentence is about he. Both are correct; it just depends on what the speaker is emphasizing.


Where on-line can I find a GIS land use .lyr that shows standard colors for each land use code?

Question: I have been looking on-line for a GIS land use layer file that shows all the standard colors that represents each land use code.  I have not been successful in finding that.  Would you please direct me to where I can find this layer file on-line?
Comment: Please don't use thanks in advance in your question, please give thanks by voting on answers.  in relation to your question, are you certain that standard colours exist for land-use (globally) or have you seen a map of land-use somewhere and would like to use those colours.  Please edit your question to add more details.
Comment: are saying there is a global standard for land use codes/colors? I have not seen this. It is important to be consistent if you're using a color schema to represent land use but for your maps only not a global standard i do not think there is one.
Answer: I did not see any standards for land use classification in general because it depends on each country's standard. You need to refer to the standards applied in Ministry of land or Land Bureau in the target country and ask them to give you the color standards applied in their organization.
For example, the American Planning Association defines its own standard, as you can see in the PDF Document: Land-Based Classification Standards. Another example in Cambodia, they also defines their own land use standard in this document: Traditional Color Coding for Land Uses. The same can be found in each country's related organization as stated earlier.


Word for being intentionally humourous and dense to misrepresent a point

Question: What's that word for when somebody in an argument is being intentionally humourous and dense to misrepresent a point ? Thank you very much
Comment: It might be "facetious"?
Answer: There's also 'flippant' which means to be intentionally humourous and dense without taking the point seriously. To be facetious you need to actually take the point seriously enough to bother making an effort to misrepresent it, so I guess being facetious is harder work than being flippant ;)
Answer: (Answer was given in a comment, so creating this as Community Wiki)
The word requested is facetious.  The definitions given by M-W are:

1 : joking or jesting often inappropriately : WAGGISH
  // just being facetious
2 : meant to be humorous or funny : not serious
  // a facetious remark


How to make rain look like snow in Minecraft?

Question: Tis' the season, and I'm making a Minecraft Christmas resource pack, and I'm trying to make the rain look like snow. I've tried renaming all the files to do with snow to "rain" and putting them in the environment folder in the textures folder. What am I doing wrong?
Comment: Can't think of the command right now, I think it's something like "setbiome"? I beleive you can change the biome to a tundra (or similar cold biome)
Answer: For Windows
Are you using Windows?
Put everything back how it was, then just change the textures in the Weather.png file to snowflakes. If you are not using Windows or need any additional help, just reply back.


Advanced OptiX denoiser settings missing in 2.91

Question: Where are the advanced OptiX denoiser settings like radius, strength, feature strength, etc. in 2.91? They were in the view layer settings in 2.83, but I can't find them any more.
Comment: You have to select one of the denoising options from the Render Properties tab (pick a denoiser and check the box), Once you've done this, the denoise settings will appear in the bottom of the View Layers tab.
Comment: I did have the denoiser selected, but if you pick OptiX or OpenImageDenoise you only get an option of input passes without further options to tweak, unfortunately.
Answer: Figured it out. These settings are only for the NLM denoiser, not for OptiX (nor OpenImageDenoise). I somehow misread the docs at https://docs.blender.org/manual/en/latest/render/layers/denoising.html.


Can wp_strip_all_tags be used as a substitute for esc_url, esc_attr & esc_html?

Question: esc_url, esc_attr & esc_html are used to escape content that is untrusted so that potentially malicious code isn't executed. Can wp_strip_all_tags be used as an alternative? If not, why?
Comment: No, escaping HTML output is not same as stripping/removing/sanitizing HTML from output. Consider e.g. if you need to display HTML code in your blog.
Answer: Not necessarily. They do different things. wp_strip_all_tags() strips HTML tags from a given string, but that's not the only reason you escape things. esc_attr(), for example, ensures that " characters are escaped so that a value doesn't break HTML attributes.
For example, if I have a variable whose value is the string my-"class, and I want to put it into an HTML attribute:
$my_class = 'my-"class';
echo '

';

The resulting HTML will be:

Which is invalid HTML, because the " in my value has closed the HTML attribute. wp_strip_all_tags() will not help you here.
Comment: Thanks. When should `wp_strip_all_tags()` be used?
Comment: When you want to strip tags from a string? I don't know really. I've never needed to use it. It might make more sense using it for sanitisation, so that tags are removed from a value on saving it, rather than on display, since this would communicate to the user that HTML tags are not allowed, while escaping just causes them to be displayed as plain text.


turning wso2 into a pep with identity server acting as the pdp

Question: I am trying to use wso2 ESB server as a PEP, I already have wso2 identity server acting as the PDP and an application hosted on wso2 Application server.  I have uploaded policies into identity server and I was wondering if there any tutorials out there that both show and explain how to make this happen. I have tried the blog http://wso2.org/library/articles/2011/08/finegrained-authorization-restful-services-xacml but it has not worked.  any direction on how to turn esb into a pep would be appreciated
Answer: You can use wso2 esb Entitlement mediator. Have a look at following guide which explains how we can add fine grained authorization to proxy services.
http://docs.wso2.org/wiki/display/IS400/Adding+Fine-grained+Authorization+for+Proxy+Services+in+ESB


Are AA battery and 18650 battery the same?

Question: I have an Antex SZ004W0 wireless soldering Iron which uses three 1.5V, AA batteries, but I don't know if it supports rechargeable batteries. I know that it supports non-rechargeable battery named "Kodak Max LR6" because I tried.
When I tried to find the best rechargeable AA battery on Amazon or Ebay I got a 18650 battery) which has dimensions: 6.5 x 1.8 cm.
Based on the dimensions being different, I think that AA battery and 18650 battery are not the same.
Which one can I use in my soldering iron?
Comment: It's obvious that the 18650 isn't the right choice due to the output voltage which is more than twice the output of the most common alkaline batteries your soldering iron needs 4,5 volts and will get 10,4 volts using the 18650 batteries.
Comment: LR6 means AA alkaline, regular Duracell or Energizer (or store brand etc) would be equivalent to the Kodak.  The Energizer L91 in your second link is intended as a drop-in replacement for alkaline which uses lithium-based chemistry instead.  The voltage is slightly higher (maybe 0.2V higher or so when brand new) but they will work fine in most, perhaps nearly all, products which can run from alkaline.  They have 2-3 times the energy storage at lower drain rates and may provide much more than that compared to alkaline in high-drain applications.  They cost more and aren't rechargeable though.
Answer: An AA cell is not the same as an 18650 cell. 18650 designates lithium-ion batteries of nominal voltage 3.6 Volts each. These typially consist of the actual lithium-ion battery and some circuitry, as shown in this image:
 (source: WikiPedia)
Primary (non-rechargeable) AA cells are typically around 1.5 Volts each, such as the classic Zinc-Carbon batteries, as well as some Alkaline batteries.
Rechargeable AA cells have nominal voltages that vary with the chemistry: Nickel-Cadmium and Nickel-Metal-Hydride ones are around 1.2 Volts each, Nickel-Zinc are around 1.6 Volts.
In brief: No, the 18650 cells can not be used in place of standard AA batteries, rechargeable or otherwise: The nominal voltage of the 18650 is significantly different from the 1.5x3=4.5V of the three AA cells, assuming those are connected in series. In case the AA cells are connected in parallel to supply sufficient current to heat the element, that's worse, as the voltage of the AAs would be 1.5 volts nominal.
Comment: The Antex SZ004W0 is designed to work with AA cells, and will kind-of work with NiCd rechargeable AA cells as well. The time to heat up will be greater, and the batteries will last a very short while before needing recharging. You might do better by using Alkaline AA (non-rechargeable) cells instead of regular Zinc batteries.
Comment: So what do you suggest? Should I buy AA battery for my Soldering Iron?
Comment: does or not it support rechargeable AA battery?
Comment: @NoBugs You have a point. Edited.
Comment: @AnindoGhosh In fact some flashlights have an adapter in case you don't use 18650, where 3 AAA can be equivalent.
Comment: Note that the original poster said it takes *three* AAAs, that would be *more* voltage than the 18650 if the AAAs were completely new.
Answer: If you have a physical adapter case, 1 X 3.6 V lithium ion battery may suffice your application although it will be weak compared to 1.5V*3=4.5V. On the other hand, it will be as strong as 3 X 1.2V AA rechargables. Also, keep in mind that a 3.6 V rechargeable lithium ion battery actually gives an output starting at 4.2 V and ends at 3.0 V, so it likely won't perform as bad as you expect. It's also rechargeable which will save you lots of money in the long run.
Also, do NOT buy any kind of UltraFire battery. They're known to have lots of copycat manufacturers which relabel batteries incorrectly. There's no such thing as a 5000mAh 18650 lithium ion battery. Anything above around 2400 or 2600 mAh should be thought of as suspect. People who've tried these 4000-5000 mAh batteries have found them to die early and have less juice than a 1000 mAh battery.


How to load a user field in template_preprocess_comment()

Question: I added a country field to users and want to show it below the username on comments (in the Bartik theme).
How can I load that field into the bartik_preprocess_comment() function?
Answer: Drupal already loads the user object. You can see the user object on that function:
function bartik_preprocess_comment($variables) {
  $user = $variables['user'];
  // Full load user
  $user = user_load($user->uid);
  // Now access your field
  $country = field_get_items('user', $user, 'field_country');
  if ($country) {
    $variables['author_country'] = $country[0]['safe_value'];
  }
  else {
    $variables['author_country'] = '';
  }
  // On your comment.tpl.php using $author_country
}

Comment: fantastic! Thanks so much for the detailed help!!! For future reference here are the 2 lines to get the country name and a icon of the country flag:   `$variables['user_country_name'] = $country[0]['safe'];
    $variables['user_country_flag'] = theme('countryicons_icon', array('code' =>  $country[0]['iso2'], 'iconset' =>  'shiny')); `
Comment: `$variables['user']->uid` is the user ID for the user who is viewing the comment, not the user who created the comment. This code is showing the flag of the user who is viewing the comment, not the comment author. See the other answer. It's a shame users need to read two answers, and the comments for the first answer to understand which answer is correct.
Answer: template_preprocess_comment(), the preprocess function that is called before MODULE_preprocess_HOOK() and THEME_preprocess_HOOK(), uses $variables['user'], but from the code it is using, I take that variable contains the user object for the user who is viewing the comment; differently the CSS class it is adding would not be "comment-by-viewer" ($comment->uid is the user ID for the author of the comment).
if ($comment->uid === $variables['user']->uid) {
  $variables['classes_array'][] = 'comment-by-viewer';
}

If you want to load any field associated with the user who created the comment, you can use $comment->uid, and pass it to user_load().
In fact, template_preprocess_comment() contains the following code, which means that $comment->uid is the user ID of the user who created the comment; once compared with $variables['node']->uid, the code is able to say that the comment was created by the node author.
if ($comment->uid == $variables['node']->uid) {
  $variables['classes_array'][] = 'comment-by-node-author';
}


I am having trouble installing Retroarch?

Question: This website is teaching me how to install retroarch.
http://ubuntuhandbook.org/index.php/2013/11/install-retroarch-emulator-ppa-ubuntu/
I enter the first line in the terminal, the one that installs the PPA.
"add-apt-repository ppa:hunter-kaller/ppa"
And in return, I get this:
"Error: must run as root"
I am quite confused. Help?
Answer: All the commands mentioned should be run as root, you can do this by prefixing the commands with sudo - so you need to run these instead:
sudo add-apt-repository ppa:libretro/stable
sudo apt-get update
sudo apt-get install retroarch libretro*

Sort of simple explaination of sudo here, more complicated one here
Please comment if you feel you have better examples.
Comment: For Ubuntu 14.04 and newer, it is better to use the new PPA "ppa:libretro/stable". (More info: http://www.libretro.com/forums/viewtopic.php?f=35&t=2351)


Looking for an assisted reading/translation program or some other kind of aid

Question: I am trying to read a novel in Japanese, now i have never done this before. I am fairly good with kanji and can get by with most manga as long as there isn't too many because of the pictures help lead me in the right direction to remember the translation. i am having a bit of a problem with reading a book however. its set in a fantasy type world with demons magic etc and a lot of weird kanji show up. Is there some convenient way/program to help look up certain parts of what i am trying to read quickly? i have pdf versions as well as picture versions of the book. I guess i would like some kind of assisted version of a pdf or w.e reader. i know theirs a good program for Vn's that lets u just click on individual kanji to look up there meaning etc. any such thing forbooks/managa?
Comment: I'm not trying to be sarcastic, but if you have PDF versions couldn't you just copy the kanji from the PDF into an online dictionary?
Comment: Most defiantly but this is super inconvenient especially if your unsure what the word is or you have multiple items. being able to left click on a kanji and have a program list all possible readings is well way faster than copy goto website paste read options maybe go back and get a couple more characters re-search etc.
Answer: KanjiTomo sees to work pretty well it can handle pictures as well as pdfs and other document types. basically left click on what u want to be added it will auto pick a number of characters after which u can easily reduce or increase it gives several possible translations massive time saver!


Calculate $1\times 3\times 5\times \cdots \times 2013$ last three digits.

Question: Calculate $1\times 3\times 5\times \cdots \times 2013$  last three digits.
Answer: If $N=1\times 3\times 5\times \cdots \times 2013$
we need to find $N\pmod{1000}$
Now $1000=8\cdot125$
Now, $1\cdot3\cdot5\cdot7\equiv1\pmod 8$  (Find one generalization here )
So, $(1\cdot3\cdot5\cdot7)\cdots (2001\cdot2003\cdot2005\cdot2007)\equiv1\cdot1\cdots\cdot1\cdot1\equiv1\pmod 8 $
So, $N\equiv 1\cdot2009\cdot2011\cdot2013\pmod 8\equiv9\cdot11\cdot13\equiv1\cdot3\cdot5\equiv 7\pmod 8$
Clearly, $125|N\implies N\equiv0\pmod{125}$ as $125$ is a factor of $N$
Now applying the Chinese Remainder Theorem,
$$N\equiv 0\cdot b_1\cdot\frac{1000}{125}+7\cdot b_2\cdot\frac{1000}8\pmod{1000}$$
 where  $b_1\cdot\frac{1000}{125}\equiv1\pmod{125}\text{ and } b_2\cdot\frac{1000}8\equiv1\pmod 8$
We don't need to calculate $b_1$ as it's multiplier is $0$
$125b_2\equiv1\pmod8\iff 5b_2\equiv1\pmod8$
Trying multiplication of $5$ with numbers coprime to and $<8,$ we get $b_2\equiv5\pmod 8$
So, $$N\equiv7\cdot5\cdot125\pmod{1000}\equiv(8\cdot4+3)125\equiv3\cdot125\equiv375\pmod{1000}$$
Answer: You don't have to calculate all that. What are the possible values of the last three digits given that N is odd and divisible by 125? Now use lab bhattacharjee's result that N is congruent to 7 mod 8.
Answer: you need to calculate $1\times3\times5...\times55$,then you see the pattern,you only need to calculate last 3 digits.
I think you can find the answer by your self now.
I add some interesting fact:
for last 2 digits, the circle is from 15, the pattern is 25,25,75,75.
for last 3 digits, the circle is from 25, the pattern is,625,875,375,625
for last 4 digits, the circle is from 25, the pattern is, 625,6875,9375,625,625,1875,9375,5625
for the last 5 digits, it also repeat at 16 numbers.
when you calculate last 3 digits, you must care if it is over 101, ie:$ 1\times 3\times5...\times101$,then for the 3rd digit, if it is odd number ,you have to add 500 to last 3 digits, it it is even, then it is same.
for example, 2013, the 3rd digit is 0, so you can direct calculate: 2013 same as 1013(8 times),1013 same as 1013-800=213,213 same as 213-160=53,53 is same as 53-24=27, which is 375.
if we ask 2113, then 3rd digit is 1,so for the final number ,you need to add 500. 2113 same as 113,113 same as = 113-88=25, the original number is 625, add 500 ,it is 1125, so the last number is 125.
for last 4 or 5 digits, since more number will effect the result, so you have to more complex calculation which may not so straight forward.
this method is not so "mathematical", but it can directly show the period of last some digits which may cause some interesting to the students.
And my question is :why the last 2 or 3 is repeat in such way, can anyone predict what is the circle numbers(16 numbers) for last 5 digits and from where?
Comment: I think $55$ is the smallest positive integer$\equiv7\pmod 8$ when $N$ is divisible by $5^3.$ But how you are going to calculate $1\cdot3\cdot5\cdots53\cdot55?$ Also $2013\equiv5\pmod 8\not\equiv7$
Comment: could you please share how you have identified $55?$
Comment: your method is right one. the 55 is simply the pattern repeat 3 times. the pattern is 625,625,875,375 from 31 and then repeat. when I post my result, I haven't see your answer.
Comment: yes, I calculate for last 3 digits in excel table, it is a small task. it is a "short cut".;-P.+1 for your answer.


Stockfish evaluation of a position from PGN

Question: I am trying to get Stockfish's evaluation of a board position(which is in PGN format) using command line.I know it accepts board position in FEN format, but is there any way i can provide PGN format?
If no, how can i convert PGN format to FEN?
Is there any tool in Python which can help me out?
Comment: This is great, but is it possible to update the code for the latest version of the chess lib?
Answer: Yes there are easy ways to do this. I'm going to briefly show you one quick way of doing it in python, using the python-chess module.
If the in-code comments are not enough, feel free to ask for clarifications or possible extensions of the code:
To showcase a working example, I've taken a game between Adams and Kasparov, you can download the PGN from the hyperlink. And our engine is the latest Stockfish available taken from the official website.
Lets call it PGNeval.py:
import chess
import chess.uci
import chess.pgn
import sys

arguments = sys.argv
pgnfilename = str(arguments[1])

#Read pgn file:
with open(pgnfilename) as f:
    game = chess.pgn.read_game(f)

#Go to the end of the game and create a chess.Board() from it:
game = game.end()
board = game.board()

#So if you want, here's also your PGN to FEN conversion:
print 'FEN of the last position of the game: ', board.fen()

#or if you want to loop over all game nodes:
#while not game.is_end():
    #node = game.variations[0]
    #board = game.board() #print the board if you want, to make sure
    #game = node

#Now we have our board ready, load your engine:
handler = chess.uci.InfoHandler()
engine = chess.uci.popen_engine('...\stockfish_8_x64') #give correct address of your engine here
engine.info_handlers.append(handler)

#give your position to the engine:
engine.position(board)

#Set your evaluation time, in ms:
evaltime = 5000 #so 5 seconds
evaluation = engine.go(movetime=evaltime)

#print best move, evaluation and mainline:
print 'best move: ', board.san(evaluation[0])
print 'evaluation value: ', handler.info["score"][1].cp/100.0
print 'Corresponding line: ', board.variation_san(handler.info["pv"][1])

Lets test it with the aformentioned game PGN, our command is:
python PGNeval.py adams_kasparov_2005.pgn
And here's the output I get:
FEN of the last position of the game:  br3r2/5ppk/p2pp3/4b1BP/N3P3/q4P2/1PnQB3/1K4RR w - - 4 27
best move:  Qxc2
evaluation value:  -10.87
Corresponding line:  27. Qxc2 Rfc8
Comment: my pleasure. Have fun playing around with this module, it's well written.
Comment: yes, just loop over the nodes, I've added one way of doing this in the edit.
Comment: Is there any way i can traverse to any node of a game(not just end node)?
Comment: `variations` gives you all child nodes which you are re-assigning to `game` to traverse till end. Thanks phonon for your help.


What should I do, reinforcement learning agent gives different result on every train?

Question: I'm using PPO+LSTM to create a trading bot. The agent is trained on 3 years of data and  tested on 1 year. Every time I train the agent with same set of hyper-parameters, I get very different results on testing data (portfolio change at the end of test period). I think, its happening due random initialisation of NN parameters and solution reaching different local maxima. So, how am I to evaluate the agent if it gives anywhere from negative to positive change on every train?
Comment: Is the trading bot trained *only* on price data? If so, there is typically no usable pattern in that, and you should expect the bot to do about as well as throwing darts at a board with "buy" and "sell" written on it, even if your training was successful. Although there are other possibilities, including that something is wrong with your implementation or training approach or hyperparameters.
Answer: I suggest you should try fixing the seeds. Here's the code how to do it, if you are using torch and the environment is inherited from gym
import torch
import random
import numpy as np

env = import gymnasium as gym
env = gym.make("LunarLander-v2")

def set_global_seed(env, seed=42):
    random.seed(seed)
    os.environ["PYTHONHASHSEED"] = str(seed)
    np.random.seed(seed)
    torch.manual_seed(seed)
    torch.cuda.manual_seed(seed)
    torch.backends.cudnn.deterministic = True
    torch.backends.cudnn.benchmark = True
    env.seed(seed)
    env.action_space.seed(seed)

set_global_seed(env)

Comment: In that case should I experiment with various seeds? In some train session I got good results. Or should the whole process be agnostic of seed i.e. set the seed once and not revisit seed setting ever again. I'm asking this because what if the seed leads to a poor testing result.
Comment: The seed will always affect the result. [This paper](https://arxiv.org/abs/2109.08203) experiments with 10^4 seeds and finds it true. However, I recommend you to select about 5 seeds, e.g., 0, 1, 2, 3, 4, then tune the hyperparameters based on those seeds and never touch again. You can do 10 if you are unsure about it
Comment: What if I want to evaluate my architecture? I was thinking of training the agent multiple times and calculate average change which will give me a good idea of expected value of the change. What do you think of this approach?
Comment: That would be the same thing as I mentioned earlier. Fix the seed, do anything you want
Answer: The problem is not that the algorithm is getting inconsistent results and you need to nail it down to one of the "good" strategies.  It is instead that the algorithm is getting inconsistent results and you need to figure out how to get consistently good results.  Depending on how you've tested the good strategy the model could just be over or under-fit and will perform poorly in production.
If there is a good solution, on a long enough timescale value estimation should converge, no matter the initialization.  In supervised learning we turn to cross validation to give some indication that a model will do well on unseen data.  It is not enough to pick a well behaving initialization there and the principle holds in RL as well.  DQN was not impressive because the authors found a single initialization that played pong, they found an algorithm and data representation that could play pong.


How is dark matter meant to explain the faster than expected rotation of galaxies?

Question: The stars on the outer edges of galaxies go around faster than they should be. How is dark matter meant to account for this? if you just add more mass wont that just give it a greater gravitational force? So we would still expect the outer stars of galaxies to be going slower than the ones near the center. Whats the flaw in my reasoning?
Comment: possible duplicate of [How does dark matter halo outside a galaxy help to explain galaxy rotation curve?](http://physics.stackexchange.com/q/68955/)
Comment: It's the distribution of the mass that counts. If you bung a load of extra mass at the centre of the galaxy then it will indeed just increase the overall gravitational force. However the dark matter is spread throught the disk and extends outwards beyond it. This is explained in the question I've suggested as a duplicate.
Comment: So there is more dark matter the further away from the center? If this is the case why? why isn't it just randomly distributed?
Answer: Yes, more mass would mean a greater gravitational pull. A greater gravitational pull, in turn, means that an object would have to be going faster at a particular distance if it is moving in a circle.  Similar to an object tied to a string and going in a circle: the faster it's moving, the larger the required force (in this case tension).


In a thin-film transistor (on insulating substrate) what is the difference between putting a load on the source or drain side of the transistor?

Question: My question was incorrectly posed, because I didn't include the capacitor connecting the gate to one of the terminal. So in fact this question is regarding common source vs common drain comparison...
Comment: There is a lot of confusion here, are you talking about the bulk of the transistor as the 4th terminal?
Answer: For a planar MOSFET like this the designation of the source and drain is not determined by the physical layout of the transistor...the layout is symmetric. If it is an NMOS then at any given instant the terminal with the lower voltage is the source and the terminal with the higher voltage is the drain. So, \$V_{GS}\$ has a consistent meaning regardless of which physical "end" of the transistor you connect to.
Comment: I understand that, and yet it still matters which terminal in the circuit topology, that the load is added to. You didn't understand my question I believe. I added the text book describing the exact issue....
Comment: I'm sorry but your question remains unclear to me. You ask about connecting to source vs drain, and then you start asking about a fourth terminal. You write a long, somewhat disjointed, section of text and then ask a very vague question such as "why does this matter?" without being specific about what **this** is.
Comment: Sorry Elliot, please give me another shot. For a given current direction and given transistor channel doping, I don't understand why when a load is connected to the drain side or the source side it makes a difference to the overall current. Isn't the average electric field across the channel the same? This is the same thing as asking: for a given current direction and for given placement of the same load (drain or source side) then what difference does it make if the majority carrier is electron or hole in the channel? This is what the textbook is saying comparing circuit (a) to circuit (b)
Answer: you are confusing a lot of concepts, in my opinion. You should forget about thin film and OLED for a split second and think about how a transistor and how a diode is supposed to work, what the difference between a pnp and npn junction layout and why the current has to go in a certain direction.
You are referring to the bulk terminal of the transistor by any chance? not having a terminal to it does not mean it stops existing.
If you look at most diagrams of how a MOSFET is laid out it is essentially symmetrical, in discrete components source is shorted to the bulk, I cannot say for certain this is what is happening in your case, The real thing that controls the turn on is gate to bulk voltage, source if often shorted to that so a lot of literature says that gate to source voltage is responsible for the turn on.
The current direction of the N and P transistors is mostly due to the fact that the bulk itself is made of a different material.
your Vgd questions has been answered before so I will lead you to that for a more detailed answer here
the answer is not as detailed as it could be, but you can go on forever on this topic.
Comment: It's not an issue of terminal. A thin film transistor is on an insulating substrate. You need to read more carefully, I have read the answer you linked to, it refers again to a 4th terminal. Are you saying the glass substrate has a different fermi level from the channel, and this energy difference is different for p and n channel? Then say so clearly...I may not be as confused as you are :P
Comment: See the text book page I added to understand the issue.
Comment: You only care about the reasoning  behind the location of the OLED? the reason as far as I know is to compensate for the threshold voltage of the first transistor(T1(Vt)) by adding the second transistor voltage (T2(Vt)) to the data voltage stored in the capacitor.

besides that you are correct, there is no difference in where you place the OLED.

source for what I am saying (https://ikee.lib.auth.gr/record/292357/files/GRI-2017-19696.pdf) page 53

this is assuming T1 and T2 are identical TFTs
Comment: Hi Juan, but there is a difference, this is what the textbook pages are explaining in my post. If you keep the circuit the same (same OLED position, same current direction), and change from p type to n type transistor (assuming transistor spec are identical), then the overall current becomes sensitive to the OLED resistance in one type, but not sensitive to OLED resistance with the other ttype. We can ignore the OLED properties and assume a simple linear resistor.