Are these section views correct Autodesk inventor

Question: So I used AutoDesk inventor and created this machine part for the purpose of exercise , But it is preferred to not to hatch ribs in my course so is there a way to make it look like image (5 and 6) ?
original

3D Views

image 5

Free hand sketch of what it should look like
Comment: You have asked six questions on this site and not accepted answers to any of them. Can you address this? Either accept the best answer or edit your question to improve it to attract better answers.
Comment: The [Tour] is worth spending a few minutes of your time.
Comment: Ok they are on different topics about the same question also I'm new my bad
Comment: I am afriad I am not familiar with Inventor enough to be of help. However, in Solidworks is pretty simple, just check the following [video](https://www.youtube.com/watch?v=VUvV4io27AU&ab_channel=CADx). You are bound to find similar videos for Inventor.
Comment: The "original" view is **not** a cross-section.
Answer: This is the jog that John Holtz referred to I believe.  I did the following in Inventor LT.

What I noticed and not sure if there is an option for this is the vertical line in the bottom plate where the section line jogs.  Personally I do not believe there should be a line here as there is no change in material type or dimensions at the jog, but I am not an expert in the field.
UPDATE

The above was done in Inventor.  I had to jog the section line in order to get the geometry.  I then had to add a "sketch" to the drawing.  This is where I clicked on individual lines and turned their visibility off (section jog lines).  I also had to turn off the automatic hatch in Section F-F.
I then drew in the boundary lines for the rib.  I then projected the required section lines into the sketch.  Once all the lines were in place I did a manual hatch of the area.
I did a similar thing for section E-E.  I had to project the right side line work and manually hatch.  The hatch scale did not match so I had to adjust the hatch scale so it would match.
Answer: Your hand sketch of the cross section AA (from original drawing) or HH (Inventor drawing) is technically wrong. The cross section is taken through the rib, but the rib is not hatched. However,  the hand sketch is somewhat common to ignore the hatching in the rib. I doubt apps have the intelligence to ignore accurate cuts and show "common" techniques.
To get the cross section shown in the hand sketch,  the section "line" needs to have jog around the rib. It would be in the centerline on the left side, then jog to be outside the rib for the right side of the part.
Comment: Check NMech's comment above some software like Solidworks have capabilities like this, Also the video he linked explains why you would need such a feature and why it's not considered wrong , technically I can change the section but i wanted to know if there was a better way to do it
Comment: @Youssef, I had a look at that video and I think the result of omitting the ribs from the cross-section view would cause far more confusion than the proper view with hidden lines turned on. The resultant cross-section view is false. It is not what would be seen if a cross-section cut was made in the part.
Comment: @transistor BS 8888 & BS ISO 128-44  states that ribs should not be hatched.


How does short length of transmission line approximate to a wire?

Question: Suppose I have a transmission line of length \$L\$ with characteristic impedance \$Z_0\$ and load voltage \$Z_L\$. If it is connected to a ideal sinusoidal voltage source \$V_s\$, then the voltage across the load \$V_L=V_s \frac{2Z_L}{Z_L+Z_0}\$. However, I think that when L becomes very small (compared to wavelength of the source) , the line essentially acts as a short and I should get \$V_L=V_s\$ across the load. I do not understand how this approximation can be obtained by reducing the length since \$V_L\$ got from transmission line model seems to be independent of the length (and of source frequency).
Comment: A matched loaded generator with 1V out will always be 2V with no load for short lengths \$< \lambda /10\$ Or you start with 1V no load and when loaded at any length \$< \lambda /10\$ with 50 Ohms it will be 0.5V... same thing..  We only consider waveguides when rise time approaches prop delay or using tR=0.35/f with same criteria  For lengths less than this Zo = sqrt(L/C) , the L is the dominant reactance like ground lead in 10 M probes  and C is important for high impedance  like probes load capacitance on coax.  But we dont use Return Loss.  Unless you are exceeding lambda criteria. ok!
Comment: What about Zs??
Comment: Can I not consider \$Z_s=0\$?
Comment: Sure then you always get twice the rated voltage for a short line unloaded
Comment: How is a lumped circuit model valid then at small lengths of wire? How can circuit theory be done with impunity at low frequencies?
Comment: Does considering a \$Z_s\$ solve the problem?
Comment: yes.. it also is more intuitive and 0 ohm source is 2Vo and 50 ohm source is Vo when matched with 50 ohm regardless of cable length
Comment: Do you mean, for example, that a \$50\$ Hz, \$1\$ V ac voltage source connected to a \$1\$ cm wire will measure \$2\$ V across its open circuited output? That does not sound plausible and I think we could not have lumped circuit models in that case without considering reflections and the characteristic impedance of each and every little connection we make.
Answer: Background:
The equations derived in transmission line analysis are based off of standing waves. The idea is that the various impedance in the line and load will create reflections that will add and subtract until steady state is achieved. Therefore the equation you have used is based on wave reflection and standing wave theory. The "z" component which is often lost in these simplified forms is the distance from the load (and becomes negative) towards the source. This component is often set to 0 in order to find the voltage at the load.
Problem: The equation you have suggested comes with various assumptions you must consider. The main assumptions is that the forward and reverse propagating waves exhibit the same reflection and thus can both be interchanged via a coefficient. This allows us to use a multiplier to simply calcuate the reverse wave as a fraction of the forward (this is the same theory we use for optic reflections). This factor/coefficent is called the reflection coefficient and it is found using the Zo and Zl of the system.
$$\Gamma = {{Zl - Zo} \over {Zl + Zo}}$$
Where \Gamma is the reflection coefficient
Solution: So yes you could go back to the original derivation and use length and location to show that it can be used for what I could call zero-length-transmission-lines but we can actually use what you have to get to it.
The point is to remove the idea of "reflections" from the equation you have. The way we can remove it while still holding true to the original derivations is simply to state that Zo = Zl and thus no reflection will occur at the junction. If you substitute Zl = Zo into the reflection coefficient you will see it becomes zero and thus there is no reflection. Your equation stated above will also simplify to VL = Vs.
Considerations: I would recommend looking into the theory behind the derivation of these equations to better understand how they should/shouldn't be used. Also, often we use different models for what seem to be the same thing simply because certain models provide assumptions others don't. This can be seen in the consideration of capacitance in medium-length transmission lines that is not found in short-length transmission lines.
Comment: For a short line, the load impedance doesn't rotate through a large enough angle on the Smith Chart to significantly change its value.
Comment: I do not understand where the assumptions start breaking down. I think the telegrapher's equation holds even as the line becomes shorter, and in addition, the load characteristic along with KCL gives me \$\frac{V^++V^-}{Z_L}=\frac{V^+-V^-}{Z_0}\$ where \$V^+\$ and \$V^-\$ respectively are incident and reflected waves.
Comment: Putting \$Z_L=Z_0\$ is not what I am looking for actually. In fact, I am trying to understand why we never need to bother about reflections and the characteristic impedance of the line when the length is very short.
Comment: Perhaps my wording was incorrect: you are right these equations can be used in short lengths, but we must consider that they come from a basis of reflections and standing waves. In power transmission these reflections can be ignored at distances when the line is not long enough to create significant standing waves or phase changes (as @Chu mentioned about smith charts). Even at the microchip level, we even consider looking at reflections in tiny circuits because the frequency and length of the conductor relative to the power transmitted becomes significant enough to create standing waves.


Identity involving the Möbius function and the first derivative of the Riemann zeta function

Question: Working on the derivatives of the Riemann zeta function, I noted that, for any positive integer $n>1$, the following identity holds:
$$\frac{\zeta'(n)}{\zeta^2(n)}=\sum_{x=1}^\infty \mu(x) \frac{\log{x}}{x^n}$$
where $\mu$ is the Möbius function. I googled to find a proof or at last a citation of this formula, but did not find anything. My first idea to prove it was to start from some established identities involving the logarithmic derivatives of the zeta function (e.g., that relating the first derivative to the Von Mangoldt function) or the prime zeta function (e.g., that expressing it in terms of the Möbius function and the zeta function). However, I suppose that a relatively simple demonstration of this could be obtained using other simple approaches (for example, a direct application of the Möbius inversion formula). I would be interested to have confirmation of this.
Answer: It is well known that
$$\frac1{\zeta(n)}=\sum^\infty_{x=1}\frac{\mu(x)}{x^n}$$
Now differentiate both sides and also use the formula $\left(\frac1f\right)'=-\frac{f'}{f^2}$


How to use SSHPass with WSL to autostart & login a session

Question: This might seem a little confusing, but I have a server I want to SSH into but the password is kinda long and complex, I understand for security I shouldn't save my password in plain text but for my convenience, I'm not too worried. Regardless, I'm trying to make it so I can just start up a Linux distro in WSL that automatically connects me to my SSH server and logs in but I'm having trouble. My settings.json block looks kinda like:
            {
                "guid": "{46ca431a-3a87-5fb3-83cd-11ececc031d2}",
                "hidden": false,
                "name": "SSH",
                "source": "Windows.Terminal.Wsl",
                "commandline": "/usr/bin/sshpass -p 'password' ssh -o StrictHostKeyChecking=no user@host"
            },

then when I start that distro I get:
[error 0x80070002 when launching `/usr/bin/sshpass -p 'password' ssh -o StrictHostKeyChecking=no user@host']

Is there another way to do this? And yes I have sshpass installed on literally all my distros just to be 100% sure. I googled around for an sshpass Windows version but can't find it. I've also tried just using sshpass instead of /usr/bin/sshpass but it doesn't work either.
As far as I know error 0x80070002 is a file not found error, but I don't know where the command isn't being found. Does the "commandline" setting get loaded before even the Linux Kernel? Is there a way to launch the command AFTER Linux initializes?
Answer: Like the picture below, you should add the fingerprint to the .ssh/known_hosts file first.

Then add sshpass command line to the Window Termial settings.


Is there a way to get the node's local time when a block was received?

Question: As in, not the miner's timestamp in the blockheader which can be +/- 2 hours, but the receiving node's local time. My concern is the real-world time that elapses between blocks.
Answer: When your bitcoin node connects to another node it requests the current timestamp from the node.  It stores this value to calculate the offset from your PC's clock.  As you may be aware the bitcoin network calculates the network time based upon the average offset of the peers that it is connected to.  This will never alter the systems clock more than 70 minutes in regards to network time calculations.
References:
Block timestamp


Does one slow node hold up contract execution in the network?

Question: As I have been reading about smart contracts, I've learned that every node on the network executes every contract.  So is a contract considered executed only after all nodes have verified it?  What if I have a node that is really slow and takes a while to execute contracts (because that node is the resurrection of that Pentium III -- "Intel Inside!" -- box I resuced from my parents basement)?  Does that adversely hold up the folks who are waiting on that contract?
Answer: It's more like that slow "Pentium III" node, won't have a the updated state of blockchain, and affects only clients connected to that node. But not the network as a whole.
Each miner will execute the transaction against the current state, computing the new updated state, before attempting to include it in a block; including invalid transactions would result in not getting the mining subsidy reward, so they are economically incentivized to make sure state changes are valid.
If they win the block, they announce the new state to the network. Each node receives that new state and verifies the state changes are correct. Once the state change has been verified, the node will respond to queries with the new updated state. Until the new state is verified, it would still respond with the previous state.
So a "slow" node only affects its own clients, not the network. The network's view of the state will update as fast as it can, and any connected peer can update only as fast as the node it is connected to.
Comment: What do you mean by "its own clients"?  I thought a client is a full node, at least according to this -- https://ethereum.stackexchange.com/questions/269/what-exactly-is-an-ethereum-client-and-what-clients-are-there
Comment: @Dave In that case, they are using the word client to refer to an Ethereum node; with P2P systems, there is lots of room for these terms to collide. By client in the above answer, I am referring to Web3/ethers.js instances or a MetaMask instance connected to the node, issuing queries. That said, other nodes that are connected to the slow node would likely also be connected to faster nodes, so they would get more up-to-date information from those neighbours, and so the slow node is only affecting itself and dapps (maybe a better word than my use of client) directly connected to it.


Differences between expression and idiom, as well as colloquial and vernacular

Question: Expression and idiom are used interchangeably, and so are colloquial and  vernacular; albeit incorrectly.  Please advise on differences in meaning and recommend a proper usage.
Answer: An expression is broader than an idiom. An idiom refers to a type of expression, and is usually not predictable by what it states e.g. Kick the bucket means "die".
An expression refers to the way we say something e.g. We say 'get up' to mean to get out of bed. It's not an idiom, but an expression.
Vernacular refers specifically to the native speech of a certain place or class of people. It's usually colloquial as well.
Colloquial refers to any language that is non-standard or informal.
So, vernacular is sometimes informal and colloquial, but colloquial is not necessarily vernacular, because colloquial can refer to slang as well, which is not vernacular.
Use idiom only when referring to an expression that is peculiar or characteristic to a language, an expression that has already been dubbed idiom.
Expression is used to refer to a particular way of phrasing an idea, and can include idioms.
Vernacular is used only specifically to refer to "dialects'.
Colloquial is used to refer to informal and non-standard in general
Comment: I would point out that "expression" and "idiom" are nouns - they refer to particular things said. "Vernacular" and "colloquial" are adjectives: they describe styles or kinds of speech.
Comment: @Colin Fine, do you mind if I put that in?
Comment: Actually, *vernacular* can be a noun as well: "I've lived here two years and still can't pick up the local *vernacular*."
Comment: @Ham and Bacon: Be my guest. @John Y: yes, vernacular can be a noun as well, but the other distinction I made (between particular utterances and styles or kinds of speech) still holds.
Comment: Many people would say that 'get up' (= 'rise') _is_ an idiom. Cowie and Mackin, in The Oxford Dictionary of Current Idiomatic English, argued that (as a 'phrasal verb') it is an idiom. It has a single-word equivalent. Though fairly transparent, it is hardly predictable in form. Its opposite isn't 'get down'.
Answer: One more thought on vernacular. It has also assumed an extended meaning.  In addition to regional speech it can also be categorized as the idiom of a particular trade or profession, which brings it closer in definition to jargon.
Answer: All those explanations seem to go around in circles to me.  Why not just say that an idiom is a combination of words having a meaning that is not apparent from the commonly understood meaning(s) of the words in that combination?  And stop right there?  That way, an idiom can be found within any vernacular, within professional jargon, or within "proper" normal usage of the language.  And no, "idiom" and "colloquialism" are not the same.  Consider the sentence "The place where old Jake kicked the bucket is a fur piece down the road."  You have an idiom ("kicked the bucket") and a colloquialism ("fur piece down the road"), but the meaning of the latter phrase can be discerned from the face of it, so it is not an idiom.
Comment: What's "fur piece down the road"? I don't think I've ever heard it said. Is it another way of saying, "far" or "fair"?
Comment: I cannot discern the meaning of "fur piece down the road" from the face of it. What fur? Why just a piece? What's with the road? I suppose an animal got run over, but then the rest of the sentence doesn't make sense. Was Jake your cat?
Answer: Ham and Bacon provides a lot of good information, and I really just want to make some refinements to his answer (but too much just to comment).
I would say that colloquial refers to having a common, spoken quality.  That is the focus of the term.  It really does not mean nonstandard at all, just informal.  It so happens that the "standards" (such as they are) for common speech often do not meet the standards for formal speech or for writing, and only in that sense might colloquial be considered nonstandard.
Vernacular, as an adjective and near-synonym of colloquial, refers specifically to regional speech.  Unlike colloquial, vernacular does carry a noticeable connotation of nonstandard or substandard.
It so happens that idiom and vernacular are also a pair.  When used more broadly, idiom can mean regional speech, or can mean the jargon of a profession or other group of people, making it synonymous with the noun form of vernacular corresponding to the adjective discussed above.
To tie it all together:  An idiom is a vernacular expression.  Some colloquial expressions are vernacular or idiomatic, but others are merely informal.  Someone who moves to a new place may take some time to learn the local idiom or vernacular.  (In this last example, it is much more common to use the term vernacular than idiom.)


Flash higher CPU usage under OS X than Ubuntu?

Question: I recently installed Ubuntu 13.10 on a 2011 late Macbook pro. With the same version chrome and pepper flash plugin and flashblock extension to block irrevalent flash. When I watch some flash video online, I found that CPU usage is much higher under OS X Mavericks than on Ubuntu. And the MBP gets hot and fan runs very quickly under OS X, while in Ubuntu it is very cool as normal when watching same flash video online. I find it unintuitive because OS X should have better drivers than linux on MBP, making it more power-efficient and usually cooler. What could be the reason?
Comment: Do you see the same behavior in OS X under Safari?
Comment: I' ve never used safari. And I hardly use OS X on this MBP now. So, I don' t know.
Answer: Since you can't make any assumptions about how Flash for Mac or either Flash for Linux are implemented or how they utilize efficient APIs of their host OS you can't make any statements about why performance behaves so differently.
As long as graphics acceleration for video playback is available on both OS's it should be Flash's task to correctly use it.
You might want to check if Hardware Acceleration is enabled in Flash on Mac OS. To do this, right-click into a Flash-Applet and select "Settings...". Then, in the first tab (Display), you should be offered a Check-Button labeled "Enable Hardware Acceleration".

Performance is also dependent on the video codec of the media file. HD content from youtube for example only takes 10% CPU-time for me, whereas Flash content from other websites may also get my fans started.
Answer: Four things come to mind immediately that would cause what you are seeing:

The server is serving higher bitrate or a file that's encoded differently on OS X versus Linux.
The flash player code itself is better optimized on Linux than on OS X.
The code on Linux is calling better API than on OS X.
Other tasks are taking CPU or adding load on OS X and not on Linux.

My guess is a combination of several would be in play.


Accessing custom block fields from a template file

Question: I have a sidebar region "Sidebar Ad" and placed in that region is the custom block "Sidebar Ad" of type "Image" which has two fields "Image" and "Link".
When I output the block on my page using {{ page.sidebar_ad }}, I get the image and the link separate from each other, which is to be expected. What I can't figure out, and I've been trying for around 5 hours now, is how to reference the fields separately so I can wrap the link around the image.
Does anyone know how to reference those fields? Am I going about this the wrong way?
I've successfully pulled the link URL by overriding the specific block template and referencing:
{% block content %}

{% endblock %}

Referencing the image URL still eludes me.
Comment: You say to put field image inside of link field?
Comment: When I do that it keeps the image header on top of the image. I could remove it with styling but I'd prefer to bypass it altogether if possible.
Answer: This was the final solution.
{% block content %}

{% endblock %}


Permission denied (publickey) Amazon Linux aws

Question: I have two instances running on my aws. I have the same keypair for both of them. I was using both instances for long time. but today I am getting an error on one instance while trying to login through terminal if I run this command.
ssh -i mypem.pem email@example.com
Permission denied (publickey).

But If I try to login to other instance with the same pem file. It works and I can successfully login to it.
I have tried all the solutions

Permission denied (publickey) when SSH Access to Amazon EC2 instance and
Trying to SSH into an Amazon Ec2 instance - permission error

but nothing works for me
If I do
ssh -i mypem.pem firstname.lastname@example.com -v

the result is:
OpenSSH_7.4p1, LibreSSL 2.5.0
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Connecting to 52.xx.xxx.xxx [52.xx.xxx.xxx] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file mypem.pem type -1
debug1: key_load_public: No such file or directory
debug1: identity file mypem.pem-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to 52.xx.xxx.xxx as 'ec2-user'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: firstname.lastname@example.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: email@example.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: mykeyhere
debug1: Host '52.xx.xxx.xxx' is known and matches the ECDSA host key.
debug1: Found key in /Users/myusername/.ssh/known_hosts:6
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/myusername/.ssh/mypem.pem
debug1: Authentications that can continue: publickey
debug1: Trying private key: mypem.pem
debug1: Authentications that can continue: publickey
debug1: No more authentication methods to try.
Permission denied (publickey).

What I have tried
chmod 400 mypem.pem

I have also tried this
sudo ssh -i amazonec2.pem ec2-xxx-xxx-xxx-xxx.us-west 2.compute.amazonaws.com

Got this
Please login as the user "ec2-user" rather than the user "root"

then I did this
sudo ssh -i amazonec2.pem ec2-xxx-xxx-xxx-xxx.us-west-2.compute.amazonaws.com -l ec2-user

I got

Permission denied (publickey)

If I try to login to other instance with the same key. I can successfully login. Please help what actually went wrong here
Security Group on my instance is this:
Comment: try [this](https://askubuntu.com/a/1090487/2413)
Answer: If you are not running Amazon Linux, you have to change the username (ec2-user)  for specific OS.
In my case, I'm using an Ubuntu server, and I connect using email@example.com.


Upon compiling opencv, the pi is reporting that it is out of space

Question: Ok, i have an 8 gig micro SD, I've been going through the process of installing open CV on the pi, however for whatever reason, the pi runs out of space upon compiling open CV, I'm on Windows, so can anyone help me out? i understand that there is partitions that Windows cant detect, but is still need to figure this out.
Comment: Does this help? http://answers.opencv.org/question/78820/opencv-python-raspberry-pi-minimum-required-size-on-disk/
Comment: *"i understand that there is partitions that Windows cant detect"* ->
Yes, and if you expanded the root fs to fill an 8 GB card, the one it *can* detect will account for **< 1% of the total**, ~60 MB.  So if you blithely tried to compile or install openCV there it would not get you very far.  However that seems unlikely.  If Varad's answer or stevieb's comment isn't the issue, you should explain exactly what you did and what you mean by "runs out of space".
Comment: @Mike I've locked this question because your edit along the lines of "Okay, sorry silly me, just ignore this" amounts to defacing the post when in fact it's one of the comments here (the first one above, about the large amount of space required to compile openCV) that led you to this conclusion.  For future reference, if you have this kind of realization, simply add an answer of your own and it may save someone else some time in the future, whereas a question whose title has been changed to "ignore this" isn't likely to help anyone.
Answer: Execute the command disk free (df) and find the available space in root
pi@raspberrypi:~/ESP8266 $ df -lk
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/root       28353172 6080752  20809100  23% /

In this case I have a 32 Gb card which has 28 Gb of space and I have 20 Gb available. Check the same in your case as well.
If the space is less than the actual card size then you need to expand the file system.
pi@raspberrypi:~/ESP8266 $ sudo raspi-config

If your file system is already expanded you are likely to get a message like below
Comment: nope, sorry, sometimes you overlook the small things, my sd was too full, i didn't anticipate that the installation would take more than 8 gig, that's my fault
Comment: @MikePerreman Yeah but that first step whould have cleared your issue and that's why I told you to use df -lk and check the available space and used up space. Anyways I believed the answer still had your needed solution but on the very first step. :) Good Mike have a good rest of the day.


How do I seal off a cavern in Dwarf Fortress?

Question: As I was digging up/down staircases straight down the Z-level, I hit upon a cavern. I'd like to seal it off now so I don't get attacked by the underground mobs. There's only one up/down staircase that I need to seal off. How do I seal it?
Answer: As Jupotter notes, a constructed wall or floor will do the trick.
If you're in a hurry, and happen to have some spare doors or hatch covers lying nearby, you may want to build one of those first and forbid it once it's done — I believe building a door or hatch is faster than building a construction.  However, you should generally not rely on doors and hatches alone to seal off passages unless you like living dangerously, since many tougher enemies, including forgotten beasts, can destroy them.
However, there are two notable exceptions to that, one of which may be relevant here: building destroyers can't destroy artifact doors or hatches, and, for some reason (which might constitute a bug) they can't destroy hatches from below.
Answer: There are a number of ways to close a staircase, unless the mechanics have massively changed since I last played DF.
Your easiest way, that keeps your options open for the future, is to build a stone floor over the top of the hole. You could also craft and build a stone hatch and then lock it. If the up/down is part of a staircase shaft then you will have to go up a level to create a down that connects to an up on the level where your original staircase ran out. For a permanent block, you can mine out the staircase and plug it with stone.
Answer: You can put a floor on the staircase, it will prevent anything from coming trough.
Floors are build with b-C-f.
Comment: yep, but iirc you can't build on an up/down (as it occupies bottom middle and top of a block). As this is at the bottom of a shaft of up/downs he will have to mine out the one above the hole first.
Comment: Yup, you're right, i forget that. In fact, it's the Up staircase itself that block the construction, IIRC. Your solution works best.


Stopping at the original entry point in a packed file

Question: During manual unpacking, the first task is to find to original entry point. The program jumps there after the unpacking is done.
I took the bin/ls file, and checked with readelf -h that the entry point is 0x404870. I packed it with upx, and in gdb set a breakpoint at this address: b *0x404870. I expected that the program will stop there, but apparently it terminates without stopping at this address. Am I misinterpreting something?
Comment: there is no guarantee that the packer will use the same entry point it can write the unpacked stuff to any section and jump haywire over hoops and loops to trick you into failing. btw you are on wrong track when you are in the unpacking world you wont have access to original unpacked binary to set any predetermined breakpoints so read up and start unpacking manually
Comment: I know that I won't have access to the original unpacked binary. All the tutorials are for 32 bit Windows, I am on 64bit linux. I just want to get to the point when the code reaches the original entry point. Isn't the esp trick (used by the tutorials I have found) assuming that the packer uses the same entry point?
Comment: no, the esp trick is used to allow an arbitrary entrypoint value, by watching for the write to the esp, which you can then examine, and then set a breakpoint at the true entrypoint.
Comment: Another reason your approach might not work is if your target was compiled as a [position-independent executable](https://en.wikipedia.org/wiki/Position-independent_code#Position-independent_executables).
Comment: Somebody is downvoting all my questions without a comment.
Answer: Your approach doesn't make much sense, since the packer is free to move the original executable around and to map it at a different offset.
Old version of upx on Linux just wrote the file to a temporary location, then execve'd it, but I think that modern ones are now writing it in memory : You can find the OEP by breaking on stack/heap execution in GDB, like everyone is doing on Windows with OllyDBG.
Answer: My idea is to use LordPE to find what's packed with. Once you have unpacked it, ImportREC can help reconstruct your executable without the packer. I don't know what you 're dealing with, but if you check out a video of how each of them work and get the basics, you will most likely succeed.
Comment: Unfortunately as far as I see these are for Windows.


Completely Cycle Bluetooth with shell command

Question: I have a problem with Bluetooth not working at startup, in Rasbian Stretch on RPi Zero W. On the desktop toolbar, Bluetooth says it's enabled. But when I try to use it through the blueST-SDK API in a Python script, it gives me a permissions error ("Bluetooth scanning requires root privilege", even though I am running as root). If I use the GUI button to turn Bluetooth off and then on, everything works.
I would like to cycle Bluetooth on and off in this same way with a shell command, so that my program will function in automated fashion, without having to manually cycle Bluetooth first. But everything I've tried in the terminal doesn't have the same effect. I've tried:
sudo systemctl stop bluetooth (+ start)

sudo /etc/init.d/bluetooth stop (+ start)

rfkill block bluetooth (+ unblock)

All of these fail to truly enable bluetooth in the end. Only using the GUI button actually works. Any clues about what I'm missing?
Answer: I found the answer to this question in this; don't know how I missed it before.
Just use:
sudo hciconfig hci0 reset


Effectiveness of orbital railguns on ground or air-based targets?

Question: For space-based warfare,  would an orbiting satellite which was equipped with a railgun cannon be effective against a ground-based fort, or even an aeroplane, or another type of air transport? This is, of course with full data on the planet's surface, and the planet is reasonably earth-like.
Comment: For hitting moving targets, a laser would probably be better. They travel at the speed of light, and while the atmosphere would absorb some of the energy, it also takes a decent amount to deorbit a rod from God where you want it, the atmosphere will also slow kinetic weapons, and if you use a microwave or visible light laser, a decent amount of energy will get through if you have a powerful emitter.
Answer: The US and Russian governments appear to believe so, and are examining the possibility.
For serious discussion on this realm, search for the phrase "Kinetic Bombardment". For a somewhat more breathy, dramatic take, search for discussions and videos about "Rods from God".
You don't need a powerful railgun; you just need something in orbit which can fire a telephone-pole with enough force to deorbit it, and with enough accuracy to hit a target.
The missile needs to essentially be a telephone pole of metal, since it will be reentering at orbital velocities, and will be ablating. You want it to impart most of its kinetic energy into the target, rather than just burn up through the atmosphere.
Really the only major cost is getting that mass of metal up into orbit; and the only real risk is destruction or takeover of the orbiting launch platform.
Edit:
With a half-dozen or more satellites, impact time can be 12-15 minutes to pretty much anywhere on earth, and there would be little warning of a launch, since distinguishing a launch from orbital maneuvers made by the launcher would be difficult. While half the time taken by an ICBM, quarter of an hour isn't, obviously, good enough for impacting a moving target, but that's not what this is for: these are "bunker-busters", aimed at destroying nuclear missile launch sites.
A pre-emptive attack that destroyed all missile launch sides within 15 minutes would be a game-changer on the world stage, and this kind of thing is exactly why both the US and Russia have invested heavily in nuclear submarines: they are immune to such attacks, being mobile, hard to track, and protected by a large amount of water above them.
A world where kinetic bombardment was a known threat would also have similar mitigation tactics, along with just building their bunkers super deep underground.
This weapon could be used against mobile artillery emplacements, however, as these usually take more than a few minutes to set up; artillery would have to adapt to become mobile.
Temporary military encampments would also be really hard to create in a way that would protect against this form of attack. The resulting defense would be very small encampments, spread widely, or camping within civilian areas.
Answer: Yes, but ...
You are putting the railgun and projectile into orbit, at a considerable energy expenditure. Then you expend more energy to de-orbit the projectile, in a way that it impacts on the surface with several miles per second velocity and the resulting kinetic energy.

Unless you have a real lot of railguns in different orbits, you will be limited how soon and how often any one target can be engaged. Google the "ground track" of recon and Earth science sats. Same principle here.
The projectiles will probably need terminal guidance which can survive reentry, and even so it will be easier to hit a parked aircraft than a flying one.
Firing the projectile will affect the orbit of the railgun. It will need engines and fuel to compensate.

On the other hand, you get to preposition your weapon in orbit and you can overfly other countries without violating their territorial airspace. So for a few, high-value targets, it might be a good idea. As general-purpose field artillery or ADA, probably not. Unless you are arriving by starship and your ammo is in orbit to start with.
Comment: Another way to think about orbital kinetic weapons is that you are effectively trying to hit a target with a meteorite. Moving targets make that a much harder problem. We hit stationary targets all the time with capsule reentry from the ISS, but that reentry takes minutes. It's fairly easy for a plane to change direction beyond the ability of the rod to change trajectory to intercept.
Comment: @DariusArcturus, plenty of fiction got the numbers wrong, either on the railguns themselves or on the ease of lifting things into orbit. Others got the numbers right. If you **can** nail an ICBM before it hits one of your cities, the effort would have been worth it.
Comment: A quick glance at some of these comments and answers is telling me that orbit to ground fire in sci-fi is unrealistic and impractical. Have all actions scenes to date got it wrong?
Answer: "It depends", of course.
Against a static target you don't need a railgun, but merely gently de-orbit a dense projectile and let gravity do all the hard work for you (see Dewi Morgan's answer). Terminal velocity for such a weapon is about Mach 10 at sea level... a fairly respectable 3.45km/s. You might get a circular error probable as low as 10-20ft (or 3-6m in new money) which is certainly enough to take out even quite a small target, given the amount of boom the object will provide (about a tonne or so TNT equivalent).
You might think that a railgun will let you swat a target promptly without all that tedious hanging around and hit it a lot harder, but there are multiple problems here. Firstly, orbital speeds are fast (~7.8km/s for low Earth orbit) and if your railgun cannot reach those speeds then you're still just de-orbiting a projectile as if it were a rod-from-god, just slightly more briskly. And railgun limitations being what they are, your projectile will be smaller, lighter and less able to carry heat shielding and terminal guidance so your CEP will go up and your ability to hit small targets will go down.
You also have to remember though that your targets are sitting underneath ten tonnes of atmosphere. Trying to batter that out of the way of a hypervelocity projectile generates heat. A lot of heat. The rods from god are made of tungsten because it combines considerable density with a decent amount of heat resistance, but even they will be partially ablated before they hit their target. You fire a faster projectile, you'll only burn it up more quickly. Given the extreme speeds and descent angles you'd want, you can't realistically use any more ablative shielding and active cooling to help you. Save your railguns for other targets and other platforms. This isn't the place for them.
As for hitting an aircraft... dubious, depending on the aiming capabilities of your re-entry vehicle. Aircraft are small, and don't always move in an entirely predictable way, and the projectile will be going very fast so its reactions will have to be similarly quick... assuming you can fit the requisite smarts and sensors into your projectile, and have them survive launch and re-entry. You might shoot down a commercial flight this way, but probably not a hostile military flight that isn't make a pre-arranged and predictable course. Even the commercial flight won't have to manoeuver much, and there will be some lead time between you firing and the projectile entering some kind of terminal kill zone, and during that time it will be a very bright and clearly visible object. Anyone looking for such things can radio an alert. (note though that plasma is surprisingly good at absorbing radio waves and can function as a means of stealth, despite being a multi-thousand-degree brightly glowing fireball).
Finally, once you've shot your bolt, the nature of your satellite will be very obvious to pretty much everyone, and at that point is immediately vulnerable to ground launched antisatellite missiles and laser fire, or even to weapons on other killsats. You could try and shift your trajectory, but the odds of you actually escaping the notice of an angry and determined military power capable of tracking and hitting targets in space is slim. A railgun suited to hitting ground targets will very much not be suited to point defence, and after that the best you can hope for is that the debris that used to be your artillery sat hits something belonging to the other side. Bit of a gamble, that.
Answer: Even a very fast projectile has a lag time, currently railguns fire at about 7500km/hr speeds, which if my math is right is about 2km/s, which while very fast, if you're 100km up in low orbit, it's going to take somewhere between 30 seconds to a few minutes to hit something depending on where you're aiming.  Static targets, highly effective.  Moving targets, you need some type of mid-flight course correction, a smart-weapon.  Orbital railguns to smash static defenses, infrastructure, and if leading a predictable and unsuspecting target like a supply train whose speed and direction could be calculated.  Against fast-moving air targets or less-predictable ground targets, ineffective.  Think of it more like artillery than a SAM.  They're just too far away in orbit to be used that way.
Comment: It is worth noting that the speed of a satellite in low earth orbit is about 7.8km/s. A 2km/s railgun round, therefore, will provide a fairly dramatic change in orbit to its projectile, but the projectile will still descend on an obviously curved trajectory. Unless your railgun manages >8km/s, it isn't necessarily very useful in this context.
Comment: You're correct, I wasn't including the orbital velocity of the satellite in the back-of-napkin math.  The satellite would need to fire the project retrograde to ensure re-entry and not reduce its own orbit.    The satellite would need to do station-keeping after a series of launches to prevent itself from escaping planetary orbit from the recoil.  Also not included is velocity losses from re-entry.  Any way you slice it, there's a non-trivial lag time that makes hitting a moving target very problematic.
Answer: Unless you have guided projectiles, you're going to have difficulty hitting anything small, or anything moving.
Long-range anti-aircraft guns are not a thing unless you fire massive barrages (and they gave up on that a long time ago).
A hypervelocity projectile might be useful against a static target like a fort, depending on how well prepared they are for that type of attack. (ie how deeply they are dug in), and it becomes a question of how much ammo you have against how much steel and concrete they have -- or what sort of active countermeasures.


1 month baby crying since last night

Question: Our baby turned one month and some days old. He had been giving us a hard time all night. Crying and being unsettling, crying. He likes someone rocking his bouncy all the time. But we can't shake his bed
We tried everything such as turning him over, massage, tummy and back rub. My back hurts after holding him on my shoulder for a long time as I cannot stand and he won't let me sit down.
What else can we do? He sleeps in next2me crib, The closet we can get is rocking his bouncy but that too isn't enough.
What should we do?
Comment: @GendoIkari sorry, I meant to say 2.5 weeks. I will update. I guess parenting got me.
Comment: I'm confused: a month or so ago you asked about your 2.5 month old.  This is a different child?
Comment: Has he been inconsolable, or just unsettled/fussy?
Comment: @Joe yes he is my second one
Comment: You have both a 3 month old and a 1 month old?
Comment: @GendoIkari where do u think is 3 months old baby mentioned?
Comment: https://parenting.stackexchange.com/questions/39719/hungry-infant-always-ready-to-suckle-and-crying
Answer: The problem is only while sleeping or all day?
I can share with you my experience: my boy used to cry almost non-stop for 4~6 hours, then sleep for 1~2 hours (and you could see he was suffering). I complained for everybody, but everybody said: "baby crying is normal". But i knew it was not normal.
So we went to the doctor and he saw it was not normal too. So, with the help of 2 doctors we found he was allergic to milk's protein (milk allergy).
My wife had to stop eating everything that contained milk. It took around 15~40 days to make effect on her milk to the baby.
He got A LOT BETTER. But still has something wrong with him (she stoped eating eggs and soy now to try find the other factor).
We found "early"  (2 months old). Some ppl takes YEARS to find out.
Common sympthons:
* blood in feces;
* irritability;
* difficulties sleeping;
* polka dots on the skin (used google translator);
Ofc, i'm not saying your child has it. You should see a doctor. But like i said: if it happens the whole day, maybe you can have something similar to my problem. If it's only at night, maybe it's totally different. I bought a mamaroo to 'rocky' him. Works SOMETIMES hahaha.
Good luck!
edit: my son had no blood on the feces (making it harder to find out)
Answer: There are many possible reasons for a baby of that age to cry, some medical, and some 'normal'.
Possibilities include food allergy, colic (unexplained prolonged nighttime crying that is likely developmental rather than pathological), illness/pain, trapped wind, over stimulation, reflux, or a growth spurt.
If your baby is truly inconsolable (continues to cry hard even when carried, walked, taken outside, fed, whatever normally soothes him), seems unusually distressed, or shows other symptoms of illness (fever, rash, stomach illness, lethargy, etc), you should first consult a doctor.  If what you have is an unhappy baby that can be calmed but cries again soon after, with more of a 'unhappy mood' vs 'obvious distress', you can try investigate simpler causes and solutions.
If your baby is happy as long as he is held upright, it could be a sign of reflux, even in absence of excessive spitting up.  Babies with mild reflux often find the sitting position of a swing or bouncer comforting, but should not be left to sleep there, as it's not safe.  They may also feel better if held upright for a while after feeding. If you suspect reflux, food allergy, or other stomach discomforts, please get the advice of a doctor as well.
Some babies crave constant movement, and this can be exhausting for parents.  There are clip on vibrating units made for this purpose that you can add to the baby's bed or bouncy seat to give your arms a rest.  A rocking chair for you or electric swing for baby can also offer some relief from the night time pacing.  Some babies also love to be bounced in the arms of a parent sitting on a yoga ball, or pushed in the stroller in the evening to sleep.
Other soothing options are to take the baby outside for fresh air, to give a deep, warm bath, or to swaddle the baby snuggly.  Some babies respond well to soft music or white noise as well.  These are all essentially in the same family of providing pleasant sensory input that can help to improve a 'bad baby mood' or soothe an overstimulated baby's nerves.
For wind, you can do some gentle stretches like 'bicycle legs' and bringing baby's knees to tummy to help pass gas.  Don't use too much force, and try to work 'with' your baby's movements.
For a growth spurt, feed on demand, even if it seems too soon.  If you are bottle feeding consider using 'paced' bottle feeding so that the baby is able to eat more slowly.  Fussing a lot at night during a growth spurt, and poor sleep along with it, is a fact of life for many babies, and will pass.
A popular general set of techniques for unsettled infants is call 'the 5 S'.  5 S Method.  This involves swaddling, shushing, swinging (or swaying), sucking, and side or stomach position to comfort a crying baby.  You can use all 5 together, or start with one and add more as needed.  I found this was reasonably effective for my own baby, although it isn't really any less tiring than holding on your shoulder for long periods.  I sometimes used a recording of myself, or from youtube, for the shushing sounds, as I got tired or sore throat from so much shhh'ing during colic episodes!
Answer: Call a doctor.  If they are crying more than 3 hours straight or not eating every 3 hours, you need to get a doctor involved.

1 month baby crying since last night


American expat living in Germany had no income in 2015, do I need to file US taxes for 2015?

Question: I'm living in Germany right now and have realized last week that I need to declare my taxes. I am married and have a wife. In 2015 I did not work and married my wife in march. she is not a citizen or resident. In 2015 I did not work but my wife worked. Do I have to Declare taxes for 2015 even though I didn't work but my wife did? At the time I married we both lived in Germany and pay German taxes.
Comment: You are a US citizen? And you are talking about US taxes?
Comment: IRS: [U.S. Citizens and Resident Aliens Abroad - Filing Requirements](https://www.irs.gov/individuals/international-taxpayers/us-citizens-and-resident-aliens-abroad-filing-requirements)
Comment: The answers here are partly correct and partly misleading or wrong. Please download publication 54 from the IRS website to find out the rules applicable to your specific situation.
Answer: U.S. citizens generally have to file taxes every year regardless of location. This is unusual - most countries don't require this.
Assuming you are a U.S. citizen talking about filing U.S. taxes, and you made enough income to require you to file, you would do well to go to the IRS website immediately to file forms to request an extension, if that's still possible. ...
Why are you asking about 2015 taxes in 2018?? If you have not even filed taxes for the past 2-3 years, you might want to seek the advice of a tax attorney. If you're a U.S. citizen, regardless where you live or who your spouse is, you need to file if the total of your income earned anywhere exceeded a certain threshold and wasn't already taxed.
Whether to file jointly or individually is best answered by a tax attorney. Filing jointly could help you establish your relationship timeline & validity if your wife decides to apply for residency in the future, but it's not mandatory. Do whatever makes the most financial sense for your situation right now.
Whether or not you have to pay taxes is a separate matter. If you earned no income (which might be difficult to prove - were you a student? Did you collect unemployment?), or if you already paid German taxes on 100% of income earned abroad, you shouldn't have to pay U.S. taxes as well. You most likely have to file every year unless you made almost nothin. Note that there may be things like unemployment, social security payout, or other benefits that could potentially be considered "income" so you should speak with a professional.
Comment: There is a minimum income threshold for the filing requirement. Below that, you don't need to file.
Comment: Seems complicated when the working spouse is not a citizen or resident, though.  If single, the income threshold is $10,400.  Married filing jointly is double that. but I've no clue how that works with a non-citizen spouse.
Comment: @OmamArmy: June >15<. (Or in years when that's a weekend or holiday, the next business day.)
Comment: @BenMiller - good point. Wasn't aware of that. Edited response accordingly. U.S. is still one of the only countries that requires expats to file taxes while living & working abroad ... and this does seem to be a bit of an odd situation.
Comment: Expats have until June 14th to Declare their taxes.
Comment: @OmamArmy - good to know. Edited accordingly.
Answer: You are required to file, but you probably don't owe any tax as your income is probably below the maximum amount of the foreign earned income exclusion. I was in a similar situation and just mailed a few years' with of tax returns together and it was no problem. I used Turbo Tax to do the current year, printed out the forms and used those to help me fill in the previous years manually.
It is of critical importance though that you do your foreign bank account reporting and catch up on previous years if you have not been doing that. The penalties for not doing this can be severe. In my case, I didn't realize I had crossed the threshold requiring reporting them so I also did a few years at one time and included a letter explaining why I was late filing. I never heard back so I assume it was acceptable since I was a small fish.
Comment: @OmamArmy I recommend you walk through Turbo Tax or a similar program that handles expats and it will give you an idea of how you need to file. It's mostly just a wasted afternoon filing in paperwork. There's no penalties for filing late if you don't owe tax.
Comment: Particularly note there are _two_ schemes for reporting foreign accounts (FBAR aka FinCen 114, and form 8938) and you may potentially have to do both, even though it seems redundant, and they apply based on asset values even if there is no related income at all.
Comment: Even if I didn't work but my wife did?


Reputable source of learning greenhouse practices, specifically for microgreens?

Question: I am allowed to use my school's greenhouse and have some space allotted to me. I want to start growing microgreens, but most of the videos and sources I read are always trying to "sell" me something. Is there any reputable site (free to access) that has this information on yielding microgreens or just general microgreen-like plant rearing in a greenhouse environment? I am a bit out of my element since I have not frequented the greenhouse much, and like to prime myself before asking friends / teachers.
Comment: Ro Siv...you could even call this guy!!  He works with greenhouses in the college environment as well as his own...community owned/education greenhouses.  Look his number up...I do have his book but have to check it out at the library as a reference (super by the way).  Think he is in the...Georgia area?  Can't remember.  Look him up on the internet and he'll probably have his email address...he'd LOVE to help you!  This is right up his 'alley' with education!!
Answer: If you're googling how to grow microgreens in a greenhouse, you will likely get a lot of sales and information of the type you're complaining about, or information aimed at large professional growers. The other problem you might have is that any 'controlled conditions' mentioned as suitable for this type of crop may not be the same conditions created for growing other people's crops in a shared greenhouse. However, I'm having the same difficulty you're having in finding out what the 'controlled conditions' in a greenhouse might be for microgreens.
Microgreens can be easily grown on a sunny kitchen windowsill or outdoors, and anyone growing in greenhouses is usually a commercial producer, or a small producer growing for sale, so that's why its difficult to find the information you want. Maybe you can adapt the methods in the links below to the greenhouse space you've been allotted:
http://www.gardeners.com/how-to/how-to-grow-microgreens/7987.html
http://www.rodalesorganiclife.com/garden/growing-microgreens-indoors
Note there is a requirement for a minimum of 4 hours filtered sunlight or very bright daylight per day, or artificial gro lights, so the space you've been allocated in the greenhouse needs to be appropriate for this.
Answer: Bamboo's answer is very good!  The best book I've got in my library that I turn to so very often is by SHANE SMITH...super for just learning about gardening in general but couldn't have found a better source.  I think the book is called 'Green House Gardening'...or close.
Comment: I was hoping for a online source that I could go to. I doubt my local library has it.  Thanks though.
Comment: Sorry...I love books.  The internet, I am on it an awful lot, doesn't take the place of books for me...SO much work, ads, misdirection!!  Look Shane Smith up on the internet!  I have read many books on greenhouses and this guy was my absolute favorite!  He is nuts and bolts and so very readable!!  My library in PODUNK, USA...has it!!  And you know that libraries are interconnected...right?  As well as on the internet!  When one reads an entire book/s on one guy you get a feel for the overall picture of the author's knowledge.  You'll love this guy...


how do you change the keyboard shortcuts in blender 2.8?

Question: I'm trying to find the search short cut and f3 isn't working on my computer so I'd like to change it to another one.
Answer: Changing the search hotkey is available, like all of the shortcuts, in the "keymap" section of the user preferences. You  can change any shortcut there.
Answer: In the setting panel,
choose keymap
and type search in the keymap searching bar
change the key for it.


Upload file into Assets using URL?

Question: Is it possible in a front end entry form to pass the URL of a file to an assets field and have it upload that way?  Specifically, I'm trying to move an image from one assets field & upload folder to another in an edit entry form.
Comment: Just to clarify: are you moving an already uploaded file (has an asset id) to another folder?
Comment: Yes, that's exactly what I'm trying to do.
Comment: Is there two Assets fields, each specified to upload to different folders? If so, you can just remove the asset id from one field and add it to the other. Also have a look at the actionMoveFile in AssetsController. You might need to make a simple plugin.
Comment: Do you want to _move_ the file (so the file no longer exists in the original location), or do you want it to be _copied_ to the new location?
Comment: Either option would be fine with me.  What's important is that the assets field in the new channel point to the file, whether the field in the original channel still points to it doesn't matter that much.
Answer: It's not currently possible to upload assets via URL, but if we're only talking about images that are already uploaded into Craft, you could have them selected by their existing asset IDs, rather than URLs, and it would work.
First, go into your Assets field settings and check the "Restrict uploads to a single folder" checkbox.
Then in your entry form, write a UI for selecting an existing asset. Something like this:

    {% for image in craft.assets.source('images') %}

                <input type="radio" name="fields[myAssetsField][]" value="{{ image.id }}">
                {% do image.setTransform({ width: 100, height: 100 }) -%}

    {% endfor %}

Comment: Were you nearby, I would hug you in a manly fashion. 'Cause your smart.

Upload file into Assets using URL?


How to understand locality and non-locality in Quantum Mechanics?

Question: What actually is the definition of locality and non-locality?
Does non-locality in Quantum Mechanics mean however far you separate 2 entangled atoms in space, the 2 atoms can still influence each other? Doesn't non-locality mean action at distance? If not, what's the difference between them?
Comment: Are you talking quantum field theory where there are operator valued fields defined in space and locality is about operators determined by spacelike separated regions commuting. Or nonrelativistic quantum mechanics where the wavefunction is not defined on space (it is defined on configuration space)? Please clarify.
Comment: look at http://physics.stackexchange.com/q/54792/
Answer: The short answer is yes, in quantum mechanics quantum non-locality refers to the apparent instantaneous propagation of correlations between entangled systems, irrespective of their spatial separation. In quantum field theory, the notion of locality may have a different meaning, as pointed out already in a comment.
Details:
The notions of locality and non-locality in Quantum Mechanics have been originally defined in the context of the EPR controversy between Einstein and Bohr on the phenomenon of quantum entanglement.
Basically, the general "principle of locality" (Wikipedia ref.) requires that "for an action at one point to have an influence at another point, something in the space between the points, such as a field, must mediate the action". In view of the theory of relativity, the speed at which such an action, interaction, or influence can be transmitted between distant points in space cannot exceed the speed of light. This formulation is also known as "Einstein locality" or "local relativistic causality". It is often stated as "nothing can propagate faster than light, be it energy or merely information" or simply "no spooky action-at-a-distance", as Einstein himself put it. For the past 20 years or so it has been referred to also as the "no-signaling" condition.
The phenomenon of entanglement between quantum systems raised the non-locality problem first noted in the EPR paper: A projective measurement on a quantum system at one space location instantly collapses the state of an entangled counterpart at a distant location. Quantum mechanical non-locality refers to this apparent entanglement-mediated violation of Einstein locality.
The remarkable thing about quantum non-locality, however, is that it actually does not imply violation of relativistic causality. Although entanglement correlations are affected instantaneously, they cannot be harnessed for faster-than-light communications. The reason is that the outcome of the local projective measurement is itself statistic and cannot be predicted beforehand. If the same kind of measurement is performed on multiple copies of identically prepared pairs of entangled systems, the overall statistical result is that locally both systems conform to the statistics prescribed by their respective local quantum states. The "spooky action-at-a-distance" of the distant measurement gets wiped out in the total statistics.
There is already a host of related questions on Physics.SE. See for instance Quantum entanglement and spooky action at a distance and similar.
Comment: Yes on both accounts. Entanglement correlations do seem to violate Einstein causality, this is what Einstein pointed out in the EPR paper. You can measure one particle and find that if you measure the 2nd particle the result correlates with the first measurement. This has been confirmed experimentally in a variety of settings by now. But the problem is that if you try to reproduce the situation for communication purposes, quantum statistics makes it impossible to ensure that you obtain the same result as before on the first particle. Then after accounting for statistics, the violation is gone.
Comment: So entanglement correlation is truly a violation of Einstein locality, but it cannot be harnessed for faster-than-light communication because the outcome of measuring large amount of spins are statistical. Right? But what if I just take one pair of entangled system, can I measure one particle to know the outcome of the other particle? Is this kind of communication faster than light?
Comment: @udrv could you please recommend some further reading on why nonlocality after accounting for statistics does not violate Einstein's causality?
Comment: @gen Not sure what level you prefer, but for a good textbook presentation see for instance http://www.theory.caltech.edu/~preskill/ph229/notes/chap4_01.pdf.


How can I make my sauces shelf stable, other than adding acid into it since my recipe doesn't include much of it?

Question: I would like to be able to can and sell my own sauces (brown gravy sauce, chile paste sauce). There isn't much acid in the recipe of the chile paste, and Mason Jar for pressure canning is cost prohibiting in my country. Is there any other way to preserve my food products and make it shelf stable? Can I use the jar as on the picture if I were to use boiling-water canning?
Comment: About the jars you show, I assume you want to use new jars ? not old ones ?
Comment: I suspect that the lid is more important than the jar.  (the two-part lids for canning jars allows air to escape, then seals itself as it cools)  Factory made products use one-part lids, but I don't know what's required to get them to seal.  The closest that I can think of that you can get without two-part lids at home is parifin sealing, but that's only for short-term storage (of low-sugar items), and I suspect that most health inspectors wouldn't be happy with that for commercial products.
Answer: There is no way at all to do that.
If you made up your own recipe, pressure canning is out of the question. It is only safe for recipes which have been developed and tested with pressure canning in mind.
Water bath canning is generally also only advised with recipes which have been developed and tested for canning, in order to ensure that you have both the proper acidity and proper thermal behavior. If you have the skills and tools to measure pH, you might decide to go with that and do water-bath canning of your own recipes with testing each batch before and after canning. This might do it for you personally, but 1) you will have to develop recipes that taste pretty sour (which you don't want to), 2) you will still have to use proper canning jars (as answered to your previous questions, both pressure and water bath canning require Mason or Weck style jars, jars with twist-off lids as in your picture are not safe) and 3) if you are selling, your local food safety authority might not agree that it is safe just because you say you measured it.
The only feasible storage option available to you as a home cook is freezing, which makes it almost impossible to operate as a cottage food producer - you would have to ensure that the jars stay frozen the whole time until they reach the customer and the customer would have to consume them within 3-5 days of defrosting, plus it is likely to mess with the texture of some sauces.
Answer: You would need to pasteurize it or can it to sell it safely and not have issues with bacteria or botulism ..
Answer: It is absolutely possible to do this however it is not simple. Your microorganism control toolkit consists of:

water activity
temperature
ph
salinity
oxygen levels
enzymatic activity from beneficial microorganisms
preservatives (not recommended by me)

The more types of control you use the less of any type is required, but there is no magic formula. You need to educate and test.
There is type of sous-vide bag suitable for canning called a retort bag
I would be buying (or "borrowing" from the library of genesis) a number of books ranging from home-canning, to modernist cuisine, to proper food science books targeted at manufacturers.


Huge difference between question asked time and last seen

Question: I don't know whether this question is asked before or not. If it's already there, please pardon.
I recently saw a question in Stack Overflow. In that there where a lot of comments seeking the clarification about the question, but OP didn't responded to any of them. So due to curiosity I checked his profile for checking the last seen time, it was something like:

But in question page it shows:

So my question is why Stack Overflow shows two different amount of time in both cases 1 Hour and 2 Hour ? Why such a huge difference ? (I saw similar behavior many times, but ignored) Is that a bug or status by design ?
Answer: We'll have to assume that you viewed those both sometime between 23:09 and 23:24. Anytime past 23:09, they would have been seen 2 hours ago. The question, though, isn't 2 hours old until the 23:24 mark hits.
Comment: Rounding is such fun. However you do it, it's always "wrong".
Comment: Right, but how come the user wasn't "seen" when he posted his question? Ghostwriting?


Assuming that the Sun wouldn't evolve into a red giant, how long would the Earth's atmosphere last?

Question: It's not going to last forever - Jeans Escape is going to eventually act on the atmosphere after trillions of trillions of years: see http://faculty.washington.edu/dcatling/Catling2009_SciAm.pdf
Answer: This is a quick answer, but the last paragraph of the article you linked says that the process will be important within about 1 billion years. I'm not sure if this is distinct from the fact that the Sun will be significantly hotter anyway because it is gradually expanding during its main-sequence life (i.e. before it even starts to become a giant) which will heat the Earth and thus increase the Jeans escape rate.
I think what the question is really asking is: how rapidly is the atmosphere escaping now, and how long would it take the atmosphere to escape? I tried briefly to dig around for an appropriate equation. The relevant Wiki section is mostly tagged "citation needed", which didn't really help, but claims that $O_2$ is sufficiently bound that it would take more than a trillion years to escape.
For what it's worth, one can compute the fraction of gas particles that has a vertical velocity greater than the local escape velocity from the Maxwell distribution, which is basically a normal distribution.
$\int_{v_\text{esc}}^\infty f_vdv=\int_{v_\text{esc}}^\infty\sqrt{\frac{m}{2kT}}\exp\left(-\frac{mv^2}{2kT}\right)dv$
$=\int_{v_\text{esc}}^\infty\sqrt{\frac{1}{2c_s^2}}\exp\left(-\frac{v^2}{2c_s^2}\right)$
$=\frac{\sqrt{\pi}}{2}\text{erfc}\left(\frac{v_\text{esc}}{\sqrt{2}c_s}\right)$
At the surface, you can use $v_\text{esc}\approx11.2$km.s$^{-1}$ and $c_\text{s}\approx331$m.s$^{-1}$ which, according to my computer, gives $5.02\times10^{-251}$. This is a very crude approximation. Ideally you'd average over the total mass of the atmosphere with the appropriate distributions. To get a rate you'd need the acceleration, since this just gives an unbound fraction rather than how rapidly that fraction is lost. But I hope this gives some solidity to the fact that it'd take a very long time.
Comment: Wow - good answer! By acceleration, do you mean that the escape rate would accelerate as more atmosphere is lost?
Comment: No, I mean that just because the gas is unbound at a certain point in time, it doesn't mean it will escape immediately. Basically, the little calculation I made doesn't involve time at all, but just shows that the gas is almost entirely bound to the Earth.
Comment: You took the escape velocity for escaping from the earth's surface. But the atmosphere has its thickness. For a particle at 100 km altitude a much smaller velocity is needed.
Answer: What other assumptions are you going to make? Once you make one non-physical assumption, every further extrapolation is self-inconsistent. Comets are at least speculated if not accepted to make a decent contribution to atmospheric volatiles. Does comet bombardment continue at the rate it would if the Sun stayed happily main-sequence? At the presumably higher rate as if the Sun did go red giant and perturbed every orbit in the Solar System? Life continues to survive and maintains near-present-day atmospheric composition? Life gets wiped out some five billion years from now for no reason?
I don't think this question is answerable, unless you just do
logbase2(present atmospheric pressure/criterion pressure for calling the atmosphere "gone")*(Jeans escape characteristic time scale for N2),
which I believe will be the shortest of the critical components of the atmosphere.
Comment: Well - the fact is - all models have non-physical assumptions. It's necessary when we want to study one particular process in detail. Atmospheric science is full of non-physical assumptions (slab-ocean model, aquaplanet, Lovelock's daisies, etc) because we *have* to get a physical interpretation of the dynamics
Comment: There's a difference between an approximation and a non-physical assumption. The approximation has a well-defined limit of applicability.


Bass clef changed to treble clef in the middle of the music sheet

Question: If the bass clef changes to treble clef in the music sheet, would you read the bottom treble clef as the bass clef notes or treble clef notes?
Answer: Play the notes as written. The notes on either clef are defined and fixed. They do not change.

You could write any note on any clef, given enough ledger lines. Some instruments have a tradition of switching between clefs quite often, while others have a tradition of using ledger lines instead. The rules of notation say you can switch clefs or use ledger lines. It is possible for ledger lines to become inconvenient, making the clef switch more ideal.
Your question implies that there is a difference between the treble clef notes and the bass clef notes. Well yes, and no. They represent the same set of notes but they represent them on different locations of the staff.
Since this is piano notation, the switch in clefs may indicate that you left hand will be playing notes in a range that your right hand usually plays.
Answer: You would read it as treble clef. It is common to change the clef if the notes start going high. This way you can avoid adding a lot of extra lines above the bass clef, which makes it harder to read.
It is possible (and quite likely) that in some point in the song, the clef will go back to the bass one.
Comment: Those lines above the staff are called ledger lines.
Answer: To add a bit to the other answers, switching between clefs is simply a matter of notational convenience.  If lower notes--typically those taken by the left hand--are higher than usual, it may be more convenient and clearer to write them in the treble clef.  Here's a pretty clear example, from Mozart's C major sonata.  Look starting at :29, where the left hand goes higher.

If all those notes were written in the bass clef, there would be a whole lot of ledger lines as they are above the clef.  Ledger lines are harder to read, as they have fewer reference points (it's easy to confuse, say, five ledger lines with six).
Answer: In a lot of piano music, the upper staff is always in the treble clef and the lower staff is always in the bass clef. However, the point is that, regardless of the range of notes being played at the moment, the upper staff should show the part for the right hand, and the lower staff should show the part for the left hand. If the part that is to be played by one hand has to move up or down by a couple of octaves at a certain point in the music, then the sheet music can be written with a change of clef to make it easier to read.


In 1947, how many Reichsmarks would 1 U.S. dollar buy?

Question: What was the 1947 value of 7,200 Reichsmarks in U.S. dollars? What was the 1947 exchange rate of the U.S. dollar for the Reichsmark?
Comment: I have a vague memory we got a question like this before, and I was forced to answer in cigarettes.
Comment: What has your research shown so far?
Comment: @T.E.D.Oh. Perhaps you're thinking of these related questions: [How much is one 1945 German Mark to one 2016 Euro?](https://history.stackexchange.com/q/27324/26786) and [What is the equivalent buying power of one 1945 Reichsmark in 2016 Euros?](https://history.stackexchange.com/q/27343/26786)
Comment: @LangLangC - Yes, it was the latter [What is the equivalent buying power of one 1945 Reichsmark in 2016 Euros?](https://history.stackexchange.com/questions/27343/what-is-the-equivalent-buying-power-of-one-1945-reichsmark-in-2016-euros). Other than being off 2 years (which I don't think would affect answers much), and being in a different modern unit (which are directly convertible with a simple web search), these appear to be *exact duplicate* questions to me.
Comment: @T.E.D. True. Not knowing the other Qs before you identified them, they are all three quite subtle in their nuances. I am a bit uncomfortable judging on dupes in general. From 45 to 48 in both halves of G it seems not much more than one Q needs to be sign posted, the others might be still valid, but not by too much? 46/47 being the worst year all around, but not  so much focused on currency but 'money' (unsure if *I* got *these* nuances right…)
Answer: That is not really easy to answer, as the German economy was not really in orderly fashion functioning. The black market dominated many sectors of civilian life, internationla trade was "low" and most of the consumer goods were hidden away or distributed via food stamps.
Compare that to Reichsmark:

After the Second World War, the Reichsmark continued to circulate in Germany, but with new banknotes (Allied Occupation Marks) printed in the US and in the Soviet Zone, as well as with coins (without swastikas). In practice, massive inflation dating back to the latter stages of the war had rendered the Reichsmark nearly worthless. For all intents and purposes, it was supplanted by a barter economy (commonly, "cigarette currency").

One online source concludes, that any meaningful exchange rate is therefor not available for 1947:

Historical Dollar-to-Marks Currency Conversion Page
1941      – RM 2.50
1942-1949 – not available
1950      – DM 4.20

However, using an equivalent of the Big-Mac-Index you might arrive at a somewhat reasonable comparison:

Historicalstatistics.org:
Historical currency converter
  Question:
  What is the equivalent of 7200 German reichsmark [1924-1948] in year 1947 in the currency of US dollar [1791-2015] in year 1947?
7200 German reichsmark [1924-1948] in year 1947 could buy the same amount of consumer goods and services in Sweden as 50.88241517640041 US dollar [1791-2015] could buy in Sweden in year 1947. This comparison should be used if the purpose of the analysis is to compare absolute worth over time rather than relative worth.
Another way to compare the worth of money in different periods is to estimate how much labour power an amount of money could buy. 7200 German reichsmark [1924-1948] in year 1947 was the amount a male worker in Sweden received in wage for 78.3772792951862 hours work. A male worker in Sweden in 1947 received 50.88241517640041 US dollar [1791-2015] in wage for 78.3772792951862 hours worked. This comparison should be used if the purpose of the analysis is to compare relative worth over time rather than absolute worth.
7200 German reichsmark [1924-1948] in year 1947 could buy 45.99775121279953 gram gold. The price of 45.99775121279953 gram gold in year 1947 was 50.88241517640041 US dollar [1791-2015].
7200 German reichsmark [1924-1948] in year 1947 could buy 2241.470416599721 gram silver. The price of 2241.470416599721 gram silver in year 1947 was 50.88241517640041 US dollar [1791-2015].

According to helpful commentator @Snow, this would then be:

Spinning this around gives roughly 141.5 RM for the Dollar in 1947.

If another somewhat theoretical conversion rate is still desired, then Exchange Rates Between the United States Dollar and Forty-one Currencies gives an attempt at:

What Was the Exchange Rate between the U.S. Dollar and Reichsmark?
  Germany, 1947 - 1947
  1947:     269.1790 Reichsmark
Comment: Spinning this around gives roughly 141.5 RM for the Dollar in 1947
Comment: @Snow Man, you're quick. Thx.
Comment: I was using the same website to draft an answer before you got in before me.  A simple google for "historical exchange rate reichmark" go me there pretty quick and I assume the same for you.
Comment: The barter economy extended internationally, as well. In 1946-1947, George Marshall devised the 'tin toys for tinned food' program, whereby the tin toy factories were revived in the US zone of Germany, and the entire production sent to the US in return for much needed food supplies. I have a couple of live steam models from this program, marked 'Made in Germany US Zone'.
Comment: I contend that no comparison claiming 16 significant figures is "reasonable".


Is it possible to optain clips or transcripts from previous Oscar ceremonies? (38th to be speciffic)

Question: My wife's grandmother just told us that Petro Vlahos, in his Oscar acceptance speech during the 38th oscar ceremony thanked my wife's grandfather for his technical help. Is there any way to confirm this? Would the clip be online somewhere? Or are there transcripts of the Oscar ceremonies?
Comment: Disappointingly, there seems to be nothing online. I've emailed the academy - hopefully they can turn something up.
Comment: You might have to find a transcript. For time's sake they often hold the technical achievement awards at a different time and place and don't film them. This may have been different in the 60's, however.
Comment: @AndrewMartin: Thank you for doing that! I didn't think that would be possible. I hope you hear back!
Answer: The Oscars website has an Academy Awards Acceptance Speech Database with transcripts and video clips.
Unfortunately it currently only covers 1966 onwards. This page suggests other ways of viewing video from Oscar ceremonies:

Watch a video: It may be possible to view a videotaped segment of the Awards telecast at the Academy Film Archive in Hollywood. To inquire about their holdings or to set up a viewing appointment, contact the public access coordinator for the archive at (310) 247-3000, ext. 2332 or firstname.lastname@example.com. Other institutions with video coverage of the Awards ceremonies include the UCLA Film & Television Archive in Los Angeles and the Paley Center for Media, with locations in New York and Los Angeles.
Listen to audio: Audio recordings of the ceremonies, which include some of the Academy's earliest holdings, are a part of the Music and Recorded Sound Collection in the Department of Special Collections at the Margaret Herrick Library in Beverly Hills. To inquire about their holdings or to set up an appointment, contact the library's music and recorded sound specialist at (310) 247-3000, ext. 2236 or email@example.com.
Contact the National Film Information Service: NFIS, a fee-based research service of the Margaret Herrick Library, can transcribe a specific speech for you. Contact information and a description of services may be found on the library's website.
Answer: I'm not positive of your location, but if you're ever in NYC you can go to the Paley Center for Media and request a copy to view.  I'm not positive if they can actually make you a copy or not, but their library is massive and it works like any public library; you request certain clips by catalog number and you can watch them on a monitor in a cubicle.
Comment: Direct link to Oscars listings: http://www.paleycenter.org/collection/?q=academy+awards&search.x=3&search.y=10


Should a text-only ad include bold font?

Question: For designing a better ad, is it recommended to use bold font, different types of fonts, only one... Which one will be less dodged in a web site?
Comment: It depends on stuff.
Answer: If all you've got is text, then use different sizes and weights to make the most of the space.

What one or two words will grab the attention of the casual reader?  Put that in big, bold type at the optical center of your advert (i.e., slightly above the physical center).  EXCEPTION: If it's a small newspaper or magazine advert, put the grabber text at the top, because that's the convention for those media.
Arrange supporting text above and below the grabber in smaller sizes according to importance.  Don't overwhelm the reader.  Only say what's necessary.
Don't consume all the space.  Black text floating on a white background is more effective than the grey appearance of a white space (e.g. a monitor screen) filled with text.
Make sure that people know how to get what you're selling by putting that information in type that's smaller than the grabber type, but larger and bolder than the supporting type.  Put the how-to-get-it at the bottom, where people will look for it.

Good luck.


Are there any plans to migrate poker questions to poker.stackexchange.com?

Question: I sort of assume that this is all in hand by TPTB, but it would be nice to have confirmation.
Answer: No.
Migrations to and from beta sites are discouraged anyway; migrations of on-topic questions to other sites where they might be on-topic are even less popular.
And as bwarner notes, doing so could unbalance a site that's already a bit... iffy.
Answer: I think we should first make sure that the Poker site can stand on its own.  Shotgunning a bunch of already answered questions over there isn't going to do them any favors, and will cause confusion if the site doesn't survive.  Once it looks to be in a stable place, it would probably make sense to migrate questions to that site.
As a corollary, it is my understanding that poker questions are still on-topic here, though it would certainly be encouraged to ask them at the Poker site instead.


Does cooking olive oil remove bacteria?

Question: I think some water got into my olive oil bottle, which can make bacteria grow. I'm thinking of using that bottle for frying or baking, would that make using it safe?
Comment: As water and oil don't mix, you should be able to see layers for anything greater than trace quantities of water.
Answer: You can't absolutely guarantee that it's safe. Botulism spores can survive to pretty high temperatures. (The botulism toxin itself is generally inactivated at cooking temperatures, but the spores are also dangerous.)
That said... the water will separate from the oil, so if you don't see a layer of water at the bottom, then it's fine. And although there is some risk if it is there, the odds are fairly low, and I personally wouldn't worry too much about it. (If the lid has been sealed, though, and you get off-gassing when you open it, then it's probably best to chuck it.)

Does cooking olive oil remove bacteria?


error accessing path: buckets/tmp

Question: Two days after installing stellar-core, when I run ./stellar-core, I had this error:
Got an exception: error accessing path: buckets/tmp [main.cpp:671]
How can i handle it?
Answer: It might be an issue with ownership/permissions - check to ensure your buckets/tmp directory is accessible & writable by the user under which you are running stellar-core - some adjustments with chown & chmod might resolve your issue.
It would help if you include more details about your stellar-core environment; e.g. is it Stellar's quickstart docker, or SatoshiPay's docker image?
Answer: Try sudo stellar-core instead.

error accessing path: buckets/tmp


What are the differences between Cognos and SPSS modeler products?

Question: My school wants to start doing some data mining, and probably go with an IBM product. I've done a fair amount of searching, but the differences between the two products seem cloudy to those of us who haven't had experience with data mining. Can anyone offer some help, or direction, as to what the differences in these products are? Although the main goal is helping with retention and graduation rates, BI features in general are also of interest to the school.
Answer: The differences between Cognos and Modeler are very large.  Cognos is mainly a summary and reporting tool.  It does not do any statistical analysis to speak of (except when you use the part of SPSS Statistics that is optionally integrated into one of the Studios).  Modeler is a full data mining tool with many modeling capabilities.  Modeler can read and write Cognos data.


How to ignore food when it's not halal

Question: I been working in a foreign country and they have meetings at hotel and dinner. But it's not halal but still chicken and beef. How can I escape such kind of food without making anyone offended or come underfire
Comment: _I'm a Muslim and I don't eat non-Halal food_ (?!)
Comment: @ozbek that will be rude. Sound rude?
Comment: Vegetarians say they don't eat meat products and no one says that's rude of them.
Comment: You can eat beef/chicken in western societies (McDonals/Burger King, etc.). It is halal since all of these establishment is owned by Christian/Jews of whom we are allowed to eat their food.
Answer: AWW,
1) tell them you are a Muslim and only eat halal meat
2) ask for vegetarian only food.
3) Go on a vegetarian dies and say you are on a vegetarian diet
4) keep a fast. Then tell them you are fasting. They cant force you to eat.

How to ignore food when it's not halal


Why when I turn the one knob kitchen Facet from running cold water to hot water does the water stop?

Question: We just got home from a weekend away.  We actually dropped the house temperature while we were away from 70 C to 58 C (outside it was actually the coldest its been all season (-30 C)
When we got home our Kitchen Facet - which is a single knob facet - wasn't working properly.
When I ran it on cold water it runs normally - when I turn the facet to hot water the water shuts off completely.  Could it be that our hot water line froze?  Every other facet in the house works properly - so it isn't the hot water tank.  Any suggestions before I call a professional?
Answer: Sounds like a frozen pipe to me. If you can, you should turn the water off to that section of plumbing. At least until you can verify the plumbing has not been damaged.


PN532 I2C read different Sectors with custom key

Question: I am using the PN532 NFC Board. It's connected via I2C to my Raspberry Pi.
I am looking for a library/Script which gives me any Sector of a Mifare Classic NFC card. I only can find the normal Tutorials, but these are only giving me the User ID and not the data of different Sectors.
Like this tutorial: https://blog.stigok.com/2017/10/12/setting-up-a-pn532-nfc-module-on-a-raspberry-pi-using-i2c.html
I would appreciate if someone got any script to read out the Sectors of the Mifare Classic NFC Card with the PN532 connected with I2C!
Many thanks in advance
Answer: Found a Library which is working for me. With this Library I can authenticate with the right key and read out the Sectors/Blocks I want to read.
https://github.com/adafruit/Adafruit_CircuitPython_PN532
It is working totally fine with a Raspberry Pi.
Just clone the repo and install all necessary requirements. Easiest way to do this is just install with the requierements.txt
<code>pip3 install -r requirements.txt
</code>
Then use the examples to create your own python script.
Offtopic:
But now I am fucked because the guys at work want me to do the same things, which I did on a Raspi, on a Banana Pi M4. There's a Raspbian Linux Image but yeah.. Nothing is supported there and nothing works.. I hate my life.
Nevertheless thanks for helping and supporting guys
Answer: The Clssic 1/2/4K card storage is a hierarchy of fixed number of blocks of sectors of bytes each of which might be of type index, key, or data.
So it is like HDD's FAT/exFAT/NTFS format.
And like the HDD, data stored, say logical files, may be scattered in different physical sectors, sequential or indexed/hashed, and might be encrypted.
So I guess it is very difficult to read what is stored in a say, train fare card, unless you know all the detailed data declaration/encryption rules.
You might like to google to know more:
(1) How to configure MIFARE card memory layout - Holly Colbert 2006
(2) Logical Structure of the MIFARE Classic Tags, Section 3, Dismantling
MIFARE Classic,  FD Garcia etal, 2008.


What is the greatest number of yellow cards a team has got without a red card?

Question: In the Chelsea vs Spurs Premier League match on 2nd May 2016, Spurs received 9 yellow cards but without getting a red card. What's the greatest number of yellow cards a professional team has ever received without getting a red card? In theory, 14 would be possible if all 11 starting players and 3 substitutes got a yellow card.
Comment: @PhilipKendall I did say professional. I don't think U-15 counts as professional.
Comment: After your update, I've been bold and flipped this question round to the "greatest number" question. If you think this is *too* radical, please roll my edit back - but I do think it makes it a better SE question :-)
Answer: After my research , I found this :
The Battle of Nuremberg (also known as Massacre of Nuremberg) is the nickname of a football match played in the Last 16 of the 2006 FIFA World Cup between Portugal and the Netherlands at the Frankenstadion in Nuremberg on 25 June 2006. Russian referee Valentin Ivanov issued a FIFA World Cup record four red cards and 16 yellow cards, setting a new record for cards shown at any FIFA-administered international tournament.
And I think we don't have any match with 14 yellow cards for a team without a single red card.
Comment: Welcome to SE.Sport, do you know any source that confirm that this is a record for a single team?
Comment: Do you mean the record i told you that was for a match ( not for a single team )?
Answer: The obvious starter here is the Chelsea vs Spurs match mentioned in the question, where Spurs received 9 yellow cards.
Comment: Community wiki answer as it contains no content over that in the question. I'll delete this answer if/when an answer is posted with 10 or more yellow cards. I'd suggest any other examples of 9 yellow cards are edited into this answer.


Why is dishwasher water backing up in my sink?

Question: water backs up into both sides of the sink when the dishwasher first starts to drain.  I do not have a disposal and I do have an airgap.  Sink drains were clogged but just had that issue fixed.  Water now drains just fine and no longer backs up.  What might the issue be with the dishwasher water backing up into the sinks.
Comment: Dishwashers normally drain to the same pipes as your sink basin (when there is no disposer). They dump a lot of water fast too. Have you filled your sink basin and then drained it to ensure it is completely unplugged? if it is still partially clogged and running slow, that could be the reason.
Comment: I am with Jimmy Fix-it, but if you just had the issue fixed call them back and have them do it again.
Answer: In addition, if you do have a waste disposal unit the dishwasher drains into it in the disposal chamber so if it has any waste in it, it will prevent the disposal from draining the  dishwasher properly.
Answer: My parents have this problem in their kitchen sink. They don't have an air gap device (though that's mainly to ensure that wastewater draining from the sink doesn't flood the dishwasher, and IME it causes more problems than it solves when you're trying to clear a blocked drain) and the drain normally runs fine, but when the dishwasher is pumping water it will outpace the drain, to the point that if that sink is stoppered with a full basin of water, it will pop the plug and push dirty dishwasher water into the basin.
It's all about relative flow rate, and exactly how the drain is designed. First of all, the fact that both basins fill when the dishwasher is draining tells me that there is a flow obstruction beyond the T-junction of the two drains. Either that, or some yahoo calling himself a plumber put the T-junction in backwards (if that's the case, filling one basin and pulling the plug will cause the other basin to fill in a similar way). I'd call in another plumber and have him scope the drain to make sure there is no remaining blockage that could slow water drainage.
Additionally, if you have a disposer, even if it's clear at the time the dishwasher is draining, I've seen designs where the way the dishwasher drain feeds into the disposer creates a backwash that slows draining (this appears to be the problem with my parents' setup). It is often possible to feed the dishwasher line into the drain in other ways; you might look into rejiggering the line to bypass the disposer (just make sure you cap the dishwasher inlet on the disposer or you'll have a huge mess the next time you drain that side of the sink or run the disposer).
While you're at it, check your tee. Some tees have a divider that separates the "direct" flow moving straight down from the flow coming in from the side. The basic idea is to prevent a backflow of water from one sink into the horizontal drain run for the other. In my opinion, however, the design has few advantages and many disadvantages. It doesn't aid venting, and it obstructs half the pipe's diameter which restricts the flow rate through each drain and causes easier clogs especially on the disposer side.