Extruder is running backwards?

Question: I have a (HIC) version of the Prusa i3. I have recently installed the E3D v6 hotend and titan extruder. After fixing some other issues, I noticed that there is no filament being extruded. In addition, the gear looked like it was going in the wrong direction. How can I fix this?
Answer: You can either flip the connector for the motor around (i.e. plug it in backwards) or (if you are using Marlin firmware) look for the following line in configuration.h:  (using the Arduino editor open the Marlin file For your 3D Printer,  one of the tabs is labelled "configuration.h" click on that tab to bring it to the front for editing.  use the Edit, Find and put E0 in the find box, click find.  When you find the line below
#define INVERT_E0_DIR false

change false to true (or vice-versa). Note that if you go for the connector-flipping route, make sure that you only do this when the printer is turned off.
Comment: Flipping the connector can be described more precise, if your connector allows it: You can flip two leads of one(!) coil, flip the whole assembly, exchange the two coil leads (without flipping them). Whatever is easiest for you.
Comment: Also, make sure everything is POWERED OFF before you start messing with stepper motor wires.
Comment: The setting it to `true` didn't work for me.
Comment: @AustinDarga You should probably turn that into a separate question. One simple thing you should at least test: what happens if you command the extruder to turn backwards? Does it reverse direction to turn "forwards"?
Comment: @AustinDarga After changing the setting, you need to Flash the firmware and do a full seeding of the settings again.
Answer: Reverse the plug for the motor on the board. Or do firmware. Doesn't matter. *** assuming you have ramps and a standard stepper..

Extruder is running backwards?


Is it possible to run a desktop GUI VM Container on linux with any linux image

Question: Looking for way to create virtual gui desktop container inside container e.g docker or LXD whichever is better
Comment: Docker/containers are not virtualization... They are just processes running in their filesystem/network "bubble". You could have a specific app in a container that uses an X-Server on the container host but that would be complicated to setup, and there are better alternatives (Snap/Flatpak/AppImage).
Comment: It's not really accurate to say that containers are not virtualisation. https://en.wikipedia.org/wiki/OS-level_virtualisation
Answer: while not really made for it something that would appear like a classic VM (as outlined by @xenoid) you can achieve "a full remote desktop in the container" via xrdp, see this reddit post for some details.
The TL;DR would be:
<code>$ sudo apt install xrdp
$ sudo apt install xorgxrdp
$ sudo apt install xrdp-pulseaudio-installer
</code>
I think depending on the ubuntu version you might need to enable the services and then connect with the RDP client of your choice.


Am I having a power supply issue with my LED lights strips in series, or have I done somethine else wrong?

Question: I bought two LED light strips and connected them together end-to-end using a solderless snap connect. The strips are each 5 meters long, "LEDMO SMD 2835 White Non-waterproof LED Light Strip - DC12V 600LEDs 16.4 Ft 6000K 15Lm/LED High CRI80". Then at one end I connected a remote control reciever "LE® Mini Remote Controller for Single Color LED Strip Lights, RF Dimmer for 12 V DC LED Light Strips, 12A". To that I then connected a power supply adapter that is "12V, 5A Max, 60 Watt Max". It works great for a couple of weeks and then the lights just get dim. It is like they are stuck at half power. I replaced the power supply once and they were bright again for a week or two and then they get dim again. I wonder if I am burning out the power supply because I have something configured wrong?
Comment: The Amazon page for that LED strip says to power one strip with one 5A power supply.  You are running two of these strips from one supply.  You are probably drawing too much current from the power supply, and at some point it just gives up and can't handle the overload any more.
Comment: Relate the power the strip needs to the power your brick can provide
Comment: Forgive my ignorance in these areas, but how would I determine the correct power supply to use?
Comment: Unless there is an absolute need for connecting two strips together, it might be better idea to power and control them individually. Parallel currents sum up. So, if you connected two strips, you need (2 x 5A) = 10A power supply. May not be a perfect idea though, as the copper traces towards the end of power supply have to carry the full 10A current. In worse case, it could lead to a fire hazard.
Comment: yes, the strips are run along the top of my cabinets, connected to one power source and one remote control, so they need to be chained
Answer: You need to choose a power supply that has the appropriate capacity to drive your LED strips.  Since your strips need 5A at 12V to operate, and you are intending to run two strips off of one power supply, you need a power supply that can supply at least 10A at 12V.
So, search for a 12V power supply that can supply at least 10A.  If you want it to last a while, find one that can supply at least 15A.
Comment: Should I be concerned with what Vasu mentioned that there could be a fire hazard with the copper traces catching fire?
Comment: If the strips are not designed to be daisy-chained, then it could be a problem.
Comment: They seem like they are designed for that, but how can one tell for sure?
Comment: Consult the documentation provided by the vendor or manufacturer.
Comment: Alternatively, if you can estimate the wire gauge of the leads contained within the strip, you can get a rough idea of how much DC current it can support by comparing against a chart like [this one](http://www.powerstream.com/Wire_Size.htm).
Answer:
you need to calculate Watts by meter and watts total per strip.
with total wattage, calculate total watts divided by voltage.
result will be the supply amp rating.

for exeample:

watt/m - Watts x meters - Total Watts /12V = Amps needed
5.76W/m = 28W/5m = 2,4A (make at least 2,50A to be safe, 3,0A is better)
14.4W/m = 72W/5m = 6,0A (make at least 6,25A to be safe, 6,5A is better)

Hope it helps.


Garage door spring replacement

Question: Does anybody have any experience with changing Garador garage springs .   I would welcome any knowledge you have .  Cheers
Comment: I have done this several times.  It is a very dangerous DIY tasks without the proper tools and precautions during the process.  It involves multiple steps that require correctly tensioning the springs(s).  This would be one that worthwhile to check on the local shops and check their price.  I recently had one done at my son's house for about $150 including the springs.
Comment: I agree with programmer I do almost everything but these springs are seriously dangerous. New springs break and after knowing an installer that was almost killed , this is one of the very few jobs I leave to them.  I have done them and I have seen them break.
Comment: Be aware that they can be/are very dangerous to the person working on them.  Can see these answers about a similar question.   https://diy.stackexchange.com/questions/12762/how-do-i-replace-a-garage-door-spring?rq=1
Comment: The one thing around the house I will not do : did once and got smart and not hurt. I recently has the torsion springs replaced , I called "the guy".  Don't even remember the cost , but well worth it.
Answer: Some doors use a torsion spring wrapped around a bar above the door. Other doors use an extension spring which might be mounted parallel to the track on each side. Procedure is entirely different for one vs the other.
The main thing to understand is that an overhead garage door is a system with a LOT of stored energy. That in itself isn't unusual; we successfully deal with high-energy storage systems every day. Think of lithium-ion batteries in a laptop computer. Gasoline in a vehicle. Compressed air. A vehicle raised on a jack to allow repairs. To work with these things safely we think about the risks and take steps to mitigate them. Don't overheat batteries. Avoid spark and flame near gasoline vapors. Don't crawl under the raised vehicle until jack stands or cribbing are securely in place.
When working with a garage door system there are likewise precautions that can be taken to minimize risks. Lower the door to the ground if possible; if it must remain overhead then block it so it can't fall. Use pry bars of appropriate length for adding or removing tension in springs. Make sure the sockets or prying surfaces are in good condition so the pry bars will remain engaged well. Stand and keep body parts clear so that if the spring should break or a pry bar slips you (and others) are clear of the danger zone. Replace springs in pairs and tension equally to avoid overload.
It's not impossible to do but good situational awareness is vital. Some people have that knack and some don't. Honestly consider whether that's one of your strengths. If it isn't, bring in somebody who does have that knack.
The answer there in a question linked by crip659 is a good read.
Comment: No!   Raise the door and anchor it in place, with the door lowered the springs have more energy.
Comment: Also there's a thrird type of door where the spring is inside the roller that supports the door,
Comment: Thank you guys .   My overhead door has two springs each side .   There is a bracket at the bottom end which holds one loop of the spring and a pin in the middle of the door to the arm for the other end .   The only instruction there is, is lift and secure the door to release tension , then put spring on bottom bracket then lift spring onto pin .   Spring though is too strong to pull up . Too dangerous and hard for me , going for a pro
Comment: @Jasen The type of door with extension-type springs along the tracks probably should be done with the door raised (I'm not entirely sure about procedures; I've only had one of this style and never really worked on it so never had to figure it out). But the type with the torsion spring mounted on a bar above the door most definitely must be done with the door closed.

Garage door spring replacement


QGIS asks for PostgreSQL credentials multiple times

Question: I have several QGIS documents that pull layers and tables from PostgreSQL / PostGIS databases.  When I open the documents QGIS asks for the the credentials several (5-8+) times.  Each document pulls its data from a single database, the credentials given have the same level of access to all layers and tables in the database.  Is there a way to get the number of requests down to one per session?
Comment: you have to save the username as well as the password (if this changes then you will have to login multiple times).
Comment: I'm trying to get by without saving the username / password permanently.  I just want to be able to only enter it once per session.
Answer: The problem seems to have been caused by adding layers at different times.  If I add a layer to an existing project I get prompted for credentials for each time layer(s) are added.  If I start a fresh project and add all the layers at once I only get one username/password prompt.
Answer: I would recommend converting user name and password into a configuration, that is stored behind masterpassword in QGIS. This also means your user name and password are not stored as plain text in QGIS project file. I recommend reading authentication section in QGIS documentation: https://docs.qgis.org/3.16/en/docs/user_manual/auth_system/auth_overview.html
One thing to note here: If you are adding data from different machines or opening your QGIS project file from different machines, your configuration ID-s should match. You can change configuration ID by clicking a padlock and unlock it.
Answer: In my case, removing the "sslmode=disable" text from each  y the .qgs file solved the issue.
Looks like new layers added in my project do not add the sslmode param and old ones (maybe added with QGIS2 some time ago) all have the param in their datasource. This param caused asking for the user/pass two times every time I opened the project.


If an electron has 0 electric potential after passing through a resistor, how does it flow to the other terminal

Question: If an electrical circuit only contains 1 resistor, and electron's potential difference (voltage) before and after passing through a resistor is equal to the e.m.f, how does the electron have potential energy after passing through the resistor to flow to the positive terminal of the battery?
Comment: First of all an electron doesn't have a potential difference. Apart from that you are answering your own question, without a potential difference, there will be no current. Did you consider the possibility that there is no such thing as exactly 0V or +V(bat) in your circuit? In other words the conductors, the wires, are non ideal and do have an however small resistance. With your logic, not a single electron would exit the battery in the first place for the same reason. ;o)
Comment: Your entire premise is flawed. 1- An electron doesn't have a voltage, it has a charge. 2- This charge is *not* reduced in any way by having the electron pass through a resistor.
Comment: Does charge or potential difference cause the flow of current?
Comment: If a superconductive loop has fifty amperes at exactly zero potential, why do the electrons keep moving in a circle?    If you stir your coffee, and all the coffee in each circle is at the same height, how can the coffee molecules keep turning in closed loops?
Answer: In the theoretical world, wires have zero resistance - in other words they are perfect superconductors.  It requires zero potential to push an electron along a conductor of zero resistance.
In the real world, all wires have a small resistance.  That means there isn't just one resistor in the circuit, but several in series - one big one and several small ones.
Comment: And what if that portion of the circuit was superconducting?
Comment: ... and consequently, there *is* a potential difference between the "bottom" of the resistor and the negative battery terminal, equal to the voltage drop across the small resistance of that conductor.
Comment: There's no voltage drop across a superconductor.  V = IR, so if R is 0, then so is V.
Comment: So then (my point was) it's not the potential difference along that conductor that's moving the electrons. They're getting pushed along by a potential difference elsewhere in the circuit.
Answer: Firstly, remember that the current is a migration of electrons jostling and pushing each other in the general direction of the positive terminal rather than each electron shooting along the wire from negative to positive. Pushing an electron in at one end of the wire pushes one out the other end. This happens close to the speed of light even though the individual electrons are moving much, much slower than that.
Secondly, remember that the potential difference causes current to flow. Let's use another dodgy water analogy.

simulate this circuit – Schematic created using CircuitLab
Figure 1. Yet another water analogy.
Figure 1 shows a water tank with a down-pipe of resistance R1, a horizontal pipe which is relatively wide bore and has no resistance and another down-pipe of resistance R2. Water flows in the circuit due to the pressure difference between the top of the tank and the outlet (at the bottom of R2).
Question: There is no height difference (potential difference) across the horizontal pipe so how can the water have the energy to flow from left to right?
By now the answer should be fairly obvious. It's getting pushed by the potential difference in other parts of the circuit.
In the electrical circuit of your question the electrons can't all just pile up at the end of the resistor they have to continue to return to the battery. If they didn't the battery would get out of balance and refuse to supply any more out the other end.
I hope this helps.
Comment:

However if a circuit only has 1 resistor, electrons which pass through the resistor is not in between 2 points of different resistance. The electrons and the battery have no potential difference between them any more after passing through the resistor. So why will the electrons flow?

simulate this circuit
Figure 2. A single resistor water analogy.
Again, pushing the dodgy water analogy a bit further, we have two horizontal big pipes and one vertical small pipe, R1. We all know that the tank will drain despite the horizontal sections. What's driving the current is the potential difference between the top of the tank (battery +) and the open end of the pipe (battery -).
Keep asking questions if it's not clear. You are close to understanding but judging by your other question, Electric potential in a cicuit, you've got static and current slightly jumbled in your thinking.
Comment: Thanks for the help. However in your analogy above the position without potential difference is in between 2 resistors, hence the potential difference between the 2 resistors push the water in the middle area. However if a circuit only has 1 resistor, electrons which pass through the resistor is not in between 2 points of different resistance. The electrons and the battery have no potential difference between them any more after passing through the resistor. So why will the electrons flow? Thank you for your help
Comment: See update and Figure 2.
Comment: Thanks a lot! I think I've cleared up most of my misconceptions thanks to you :)


Drupal: CCK ImageField, multi-line description

Question: I'm using CCK Image field (multi-images) and for each image I have the "Description" field, where I can add the image description.
I was wondering if I can have multi-line description, instead of only one line.
(Even using some specific symbol to go next line)
thanks
Answer: If you are wanting a textarea instead of a textfield for the image description field, the only way to do this would be to create a custom module that creates a compound field. There is a really great tutorial on the state of compound fields in Drupal and how to create one here: http://poplarware.com/articles/cck_field_module.
Alternatively, if you only have one image you are uploading, you could disable the description on the image field and create an additional CCK textarea to be used as the description.
Answer: When you create CCK imagefield, there is a setting called "Title text settings", where you can set the checkbox "Enable custom title text" and select Input type: textarea instead of textfield.
So now there is nothing you must to specially to make a multiply description for your every imagefield.


Combining Swipe menu and swipe screen

Question: Is there a good way to combine a swipe menu with the ability to swipe multiple screen? Or is the idea generally bad?
The idea is to create a swipe menu to select from multiple screens(let's say 6) and as my app has 3 main screen, I would like to create a way to easily access those 3 screens without going to the menu.( just a swipe rather than a swipe and a tap).
Comment: Can we get more detail here? Low information in the question means low quality in the answers. If you can explain your specific situation we can cater the response to help that more specifically.
Comment: Would the swipe menu be swipe in one direction (i.e. from L to R) and then swipe between views be the other direction (R to L)?
Comment: Menu will come from a left to right swipe. Are you suggesting a right to left swipe for screen changes (as in round robin style - circular screen change)? Thanks.
Answer: A lot of windows phone apps have a menu that slides up from the bottom like this:

while also supporting screen swiping (used to be known as "metro style"), where the user gets a visual hint that there is something to the right

A nice description of this design pattern is here.

Combining Swipe menu and swipe screen


Using Powerpoint, how do I curve text to "bend" with the circumference of a sphere?

Question: I'm creating a powerpoint deck.  There seems to be only one kind of text box -- linear and rectangular.  How do I create a text box that "bends" with the circumference of a sphere?
Answer: Using WordArt
It's Office version specific but here's a general walkthrough:
Select your textbox, go to the Format tab at the top, look for the Text Effects pulldown menu, then to Transform where you'll see all the basic options.
Once you've selected an option you can scale the text box and change the curve to customize the look.
Comment: I wish I could attach a slide showing you the options available when I...1) click on the text box and, 2) pull down the Format tab and select "Text Box" in my version of PPT.  The option "Text Effects" or "Transform" do not show up anywhere.
Comment: On the Format tab, Word Art Styles group, pull down Text Effects, choose Transform and go to town.


Gibbs free energy for an ideal gas

Question: You know that for a generic system which during a process exchanges heat with a reservoir at a constant temperature $T_{a}$ it holds:
$$\Delta G=\Delta H-T_{a}\Delta S$$
Where:
$\star)$$\Delta G$ is the Gibbs free energy change of the system during the process.
$\star)$$\Delta H$ is the enthalpy change of the system during the process.
$\star)$$\Delta S$ is the entropy change of the system during the process.
Note that during the process (unless it is quasistatic) the temperature of the system is not defined, so it is not constant.
Said this, if I want to simplify the previous equation for a ideal gas:
$$
\left\{
\begin{array}{c}
\Delta H=n c_{p} \Delta T \\
\Delta S=n c_{p} ln(\frac{T_{2}}{T_{1}})+n R ln(\frac{p_{1}}{p_{2}})\\
\end{array}
\right.
$$
$$\Delta G=[n c_{p} ln(\frac{T_{2}}{T_{1}})+n R ln(\frac{p_{1}}{p_{2}})] T_{a}+n c_{p} \Delta T$$
Where $T_{1}, p_{1}, T_{2}, p_{2}$ are referred to the system in its inital and final state.
On my book I find written:
$$\Delta G=n R T ln(\frac{p_{1}}{p_{2}})$$
Which is the equation I got by putting $T_{1}=T_{2}$. Someone could confirm that my formula is right and the book is just considering a particular case? (The book isn't very accurate in this explanation)
Comment: Please provide the source of your initial equation.
Comment: Atkins-Jones-Lavermann Chemical principles
Comment: What exactly do they say, because this equation does not seem correct.
Comment: Indeed it is suspicious you are using incorrect equations: under isothermic process, there is an enthalpy change, yet it would be zero according to your equation. The enthalpy expression you use is the isobar expression, isn't it?
Comment: They assume temperature and pressure constant @Greg
Comment: @Landau and how do you do that? Also, fix the question because it wasn't what you asked.
Answer: It is not possible to confirm your derivation. If you describe the change in free energy of a system with the expression
$$\Delta G=\Delta H-T\Delta S$$
then you are implicitly assuming that the initial and final temperatures of the system are equal to $T$. The more general expression for $\Delta G$, from the definition $G=H-TS$, is
$$\Delta G = \Delta H - \Delta (TS)$$
From your expression
$$\Delta G=\Delta H-T_a\Delta S$$
it can be assumed that the initial and final temperatures of the system are equal to $T_a$, that of the surroundings. Given that you know that the initial and final temperatures are identical, and that for an ideal gas $V=nRT/p$, you can use a convenient reversible path to compute the change in $\Delta G$ by integrating $$dG=Vdp-SdT$$ at constant $T$, which yields the textbook expression $$\Delta G = nRT \ln \left(\frac{p_1}{p_2} \right)$$ (note here $p_1$ is the final pressure).

Gibbs free energy for an ideal gas


How can I safely exchange Bitcoins for Ethers?

Question: I would like to sell Bitcoins and buy Ethers. I know there are some exchange websites, but I cannot tell which are trustworthy. What are safest and easiest ways to sell Bitcoins and buy Ethers?
Answer: you could use poloniex or coinbase to buy ethers using your bitcoins, they are trustworty and efficient (with a high liquidity volume)
Answer: To exchange Bitcoin for Ethereum, follow some simple steps:
• Sign up with a global crypto exchange platform such as KoinBX and create an account.
• Complete the KYC verification and bank account verification.
• Once the account is created and verified, you can deposit funds into your wallet.
• Select the ETH pair that you want to exchange.
To sell Bitcoin, the user needs to place a sell order for Bitcoin. Once the order was matched with a buyer holding Ethereum and wishing to exchange Bitcoin for Ethereum, Bitcoin will be exchanged for Ethereum and deposited in your KoinBX wallet.


Removing a post from the results of a WP Query

Question: We have a complicated database query and we would like to exclude some posts. We've tried to do it with SQL, but it's really complicated. The simplest solution seems to loop through the results after the query's made and then exclude a few posts. The problem is, i don't know where to do it! I've tried to unset posts in $wp_query->posts, but they still show up. Is there a proper way to do this? Is there another array WordPress uses that I should unset from?
Comment: Please show your actual code (query) and explain your exact problem.
Answer: Do you know the ID of the posts? Have you passed post__not_in as part of your query?
<code>$query = new WP_Query( array( 'post_type' => 'post', 'post__not_in' => array( 2, 5, 12, 14, 20 ) ) );
</code>
From: http://codex.wordpress.org/Class_Reference/WP_Query. The above will return all posts but exclude the IDs specified.
Or do you have another way to group the posts you do not want i.e. by a category or author? A bit of context might help :)
Comment: It's a website for renting apartments. We want to only show properties that will be available in the next 3 months.
Comment: And how are you specifying when it might be available – custom fields?


Why won't my health go down after cheat mod disabled?

Question: So my question is about that I downloaded the cheat room mod because I got stuck in some cave because the bloodskal blade would not shoot its beam and I went to the room drank a health potion and now I un-download it, because its not fun with cheats, but now my health won't take damage, what do I do? I un-downloaded it and I'm on XboxOne and I do not want to go back to an old save. I got rid of other cheat items but my health won't go down when attacked.
Comment: Start over without cheats.
Comment: All what you can do is reload a previous save. IF that don't work, to be honest, it is out of our help since we don't really deal with modding much, less when we don't know which mod you are using. Edit your question to tell us the name of the mod.
Comment: One other thing: make sure if the Bloodskal blade works. You have to power attack to shoot the red beams.
Answer: You need to load from a save prior to when you had the cheat installed.
Console mods for Skyrim and Fallout 4 are often somewhat hacky, as they lack the options and script extension options that exist for PC.  Many mod authors who do console mods also are relatively new modders compared to those who place content on the Nexus, as many of the more seasoned modders refuse to participate in Bethesda's console mods.
What has probably happened is that the "mod" simply set your maximum health to a ridiculous amount, set your native damage resistance so high that you can't be effectively injured, or bypassed the lack of console commands by effectively setting "TGM" (godmode) to true and had no method of turning it off.
In any of those scenarios, all saves made after the mod was active will be permanently affected by the mod. This really only leaves you with one choice.


Can not Open Ethereum Wallet on Window 10

Question: I did trying install soft Ethereum wallet on windows 10, But I can't open the program. It looks like the picture below. Help me pls, Thank everyone.
Answer: The official Ethereum Wallet (and Mist) have been deprecated for a while, and it's not recommended to use them anymore. You can find some alternative options on the Ethereum website here. If you're looking for a desktop wallet, I recommend MyCrypto's desktop application. It's fully open-source (see GitHub), and you can download it from https://download.mycrypto.com. It works on Windows, as well as macOS and Linux-based systems.


Mapbox NSInternalInconsistencyException showing RMMapView on iPad

Question: Having a spot of trouble trying to get the native iOS Mapbox view working on an actual device (3rd gen iPad, iOS 7.1).
dprintf( "RMMapboxSource\n" );
RMMapboxSource * tileSource = [[RMMapboxSource alloc] initWithMapID:mystyle];

dprintf( "RMMapView\n" );
RMMapView * mapView = [[RMMapView alloc] initWithFrame:CGRectMake(0,0,900,450) andTilesource:tileSource];

dprintf( "addChild\n" );
// ... mapView then added to view hierarchy

dprintf( "setPage\n" );
// ... then make visible

Everything works great in the simulator. But trying to run on an actual iPad results in the following.
RMMapboxSource
RMMapView
addChild
setPage
2014-04-01 15:41:21.879 Protraak[1179:60b] *** Assertion failure in -[UIView layoutSubviews], /SourceCache/UIKit/UIKit-2935.137/UIView.m:5326
2014-04-01 15:41:21.881 Protraak[1179:60b] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'layout should have been successfully accomplished'

A Google search for "layout should have been successfully accomplished" came up blank.
Answer: Can you try the latest develop branch and see if that works for you?


Have been in new position for 2 months with nothing to do (experienced engineering position)

Question: just wondering some thoughts. I started a new job on a construction project as a project engineer. I have 8-10 years experience and the pay it very good. In the interview I was told I would be very busy. Now I have been at this job for 2 months and have nothing to do. I ask for work to do and and simply get told to sit tight. I don't like doing nothing because it feels like I am wasting company resources. I have been reading engineering standards for the past 2 months and it is very grueling and difficult.
So, is it okay to just do nothing at a company?
Comment: There are good answers in that possible duplicate. In the meantime though, speaking as someone who has run a team in an engineering firm, I can tell you - there may be legitimate reasons for there to be no active work right now. I'd had periods where I would hire desirable new staff but have nothing they could actively work on for half a year. The work tends to come in large chunks which makes it a challenge to average out and assign in a way that keeps everyone equally busy. And there may be contract negotiations or clearances or permits or other obstacles as well.
Answer: Well to the question "is it okay to just do nothing at a company", if the company is aware that you aren't busy and you've done your due diligence in appropriately regular reminders of that, then morally I don't think there's an issue. It's their money and you aren't deceiving them, you've made them aware of the situation.
However, the more important question is do you want to do nothing for months on end? As you've noticed, a job is more than just the pay. Even with good pay, doing nothing all day becomes very boring and frustrating. One option is to find things to study in all this downtime that could supplement your professional capabilities and improve your prospects, both for this job (if you ever end up doing anything) or for future jobs.
Though at the end of the day, if you're just wondering if doing nothing substantial all day for months is worth a big paycheck, that's something only you can decide.
Answer: Well, 2 month is a long enough time to gauge the work environment and I am hoping you were not blind to what's happening around you.
The reason I say this, there are times in a company work that, things get on hold for many reasons, just to be released in a torrent form, drowning every employee with excessive work. Two months of no real work, especially for a newbie (regardless of experience level, you are newbie to the company) is not unheard of.
So, If I were you, I would look around and see of there is a sense of extreme work for everybody but yourself. If everyone's work pace is kinda slow, you might be in one of those slow/lull periods of the company and it is okay to trust the words of "sit tight".
If this is not the case, I would ask the managers of other projects, that is going on around you (physically speaking) if they need any help. If they are strapped for headcount, they would take you up in your offer in a heartbeat, or at least seek upper management approval to include you in the project, if the company is structured enough.
If you show initiative and still can not get any real work to do, it is not necessarily a bad thing, as long as the wait doesn't reach to outrageous levels, like a year and no work is not good for anyone.


Why does the UK want to remove medicines from the scope of the Northern Ireland protocol?

Question: I've read on the BBC that the UK is seeking to renegotiate the NI protocol with the EU (which is part of the Brexit deal). I can understand why the UK sees some of the provisions as burdensome, but I'm not sure I see why it seeks to "remove medicines entirely from the scope of the protocol". Medicines are among the most controlled things on earth in terms of imports/exports and general paperwork involved anywhere, even internally in a country. It's also not the case that they are manufactured by a mom-and-pop business that can't afford a compliance department. So I'm not sure why the UK thinks medicines in particular are extraordinarily burdened by NI protocol provisions. Can someone explain, preferably with the UK's own talking points?
Answer: The government is concerned about the Protocol's requirements (Article 7) that manufactured goods placed on the market in Northern Ireland (including medicines) comply with both EU and UK regulations - even if they are only to be consumed within NI. In fact, it argues that because medicines are so tightly controlled and regulated, there would be little risk to the EU single market should an exception be made.
The two main arguments put forward in the government's command paper are that firstly, the link between medicines and the delivery of the national health service in Northern Ireland makes the risk of medicines destined for use in NI being transported to the Republic of Ireland minimal, and secondly, that the requirement that new medicines be approved by the EMA before they can be used in NI is disproportionate - it gives the example of new cancer drugs.
The paper also argues that there is a significant risk that businesses will not bother to export to Northern Ireland, given the extra regulation that is required, but this is more with regard to manufactured goods in general, rather than medicines.
To quote from the paper (emphasis mine):

[...] Medicines are at risk of discontinuation because the hurdles to clear
to reach the small Northern Ireland market make supply unviable.

Under the Protocol, Northern Ireland aligns with all relevant EU rules relating to the placing on the market of manufactured goods.
This requires products to meet EU rules if they are to be placed on
the market in Northern Ireland, but goods approved to these rules by
UK bodies are marked for sale only in Northern Ireland and Great
Britain. The current arrangements have already caused difficulties for
businesses trying to put goods from Great Britain onto the market.
These will be exacerbated further once the UK moves fully onto the new
UKCA product safety regime, leading to significant risks that many
businesses in Great Britain simply give up trying to produce goods for
the Northern Ireland market. The current system nevertheless enshrines
the principle that there can be parallel arrangements for different
goods in Northern Ireland, underpinned by risk-assessed regulatory
checks performed by market surveillance authorities to limit the sale
of goods beyond Northern Ireland.
We suggest that the right way forward would be to extend this principle to provide for a full dual regulatory regime in Northern
Ireland. Goods, whether manufactured or SPS goods, should be able to
circulate within Northern Ireland if they meet either UK or EU rules,
as determined by UK or EU regulators, and should be labelled
accordingly. Of course, goods destined or produced for the EU Single
Market would need to meet EU rules in full. Goods exported from Great
Britain via Northern Ireland to Ireland or beyond would, under the
arrangements set out above, need to meet full normal EU customs
processes.
It may be necessary to build into these arrangements specific provisions for medicines (and a small number of other key sectors).
Arrangements for medicines, for example, are so closely linked to the
delivery of national health services, an essential state function for
a modern state, and the associated regulation and control arrangements
are so substantial, that the risk of diversion into the Single Market
is extremely minimal.
Moreover the current arrangements are creating considerable challenges with medicine supply to patients in Northern Ireland being
put at risk for a number of products from the end of 2021. The
solution proposed by the EU in June was a welcome start, but is
potentially complex to operate because of its need to work within the
broader EU framework for regulating medicines; and furthermore it
would not satisfactorily deal with certain medicines (such as new
cancer drugs) which must be licensed by the European Medicines Agency.
Given the range and depth of these challenges, the simplest way
forward may be to remove all medicines from the scope of the Protocol
entirely.
Answer: I see Boris Johnson has been making a talking point out of cancer treatments:

Thirty medicines are no longer available in Northern Ireland because of rules enforced at the border with the Republic of Ireland following Brexit, the Prime Minister has said.
Speaking at the recent G7 summit, Boris Johnson reportedly said that the medicines and one innovative cancer treatment had been denied to patients because of the way regulations that were being phased in around the border were affecting the movement of goods, according to the Sunday Times.
"If the protocol continues to be applied in this way, then we will obviously not hesitate to invoke article 16," he reportedly said during the summit.

A bit more searching finds a real example of a drug involved, Osimertinib (brand name: Tagrisso) from Astra Zeneca.

When asked about the issue, the MHRA confirmed that "any extension to the licence of Osimertinib (Tagrisso) in Northern Ireland must be authorised via the EMA's centralised procedure which would automatically have effect in NI".

However it's not too clear how real the barrier to access would be:

Stormont's Department of Health told the newspaper that "patients in NI may still be able to access Tagrisso for this additional indication following a discussion with their clinician, in line with extant processes for access to new medicines."

But it has become a political talking point locally as well:

But TUV leader Jim Allister said this was "a practical demonstration that in reality, the protocol is bad for your health".

For what it's worth, I see from another BBC article that the EU response has been that: "The European Commission said its solution involves the EU changing its own rules so that regulatory compliance functions for medicines authorised by the UK for the Northern Ireland market may be located in Great Britain. The Commission will put forward a legislative proposal in the early autumn in order to be able to finish the legislative process on time."


Add js in head in magento 1.9

Question: All js script are loaded in footer in magento 1.9. I want them in head.
Can Anyone let how to do this ?
Answer: Who told you that the JS files are loaded in footer ? the JS files are declared and loaded from and in head.
Here is the native way how to include a JS file:
<?xml version="1.0"?>
<layout version="0.1.0">
    <default>
        <reference name="head">
            <action method="addItem"><type>skin_js</type><name>js/script_name.js</name></action>
        </reference>
    </default>
</layout>

Comment: In default its in head. but there is an script or something that pull the js in footer
Comment: So if I decide to remove the footer from my website, there will be no JS that will be loaded ?
Comment: Do you use an extension for page-speed?
We have an extension from amasty, that provides the function to move the javascript to the footer. Its not the default behavior of magento1 (but it can be positive regarding page-speed)
Answer: To add js in the head you can edit layout xml files where you want your scripts in the head.
Example in \app\design\frontend[your-theme]\default\layout\page.xml:
<layout version="0.1.0">
    <default translate="label" module="page">
        <block type="page/html" name="root" output="toHtml" template="page/2columns-left.phtml">
            <block type="page/html_head" name="head" as="head">
                <action method="addJs"></action>
                <action method="addItem"><type>js</type><name>script2.js</name></action>
                <action method="addItem"><type>skin_js</type><name>script3.js</name></action>
            </block>
        </block>
    </default>
</layout>

This are just some examples. Hope this helps.
Edit: I think you have a modified version of Magento 1.9 because in the default version all js are in the head.

Add js in head in magento 1.9


Distance between two pairs of 48 V, 5 kW LiFePO4 battery "pairs"

Question: I am installing a large LiFePO4 battery system in my RV. I have four server rack mount 48 V, 100 Ah batteries (EG4-LifePower4). I would like to have two on each side of the RV for weight distribution. Is it OK to make 2 banks of 2 with about 3 feet between the pairs (connected in parallel)?
Comment: Which pair would you wire the load circuits to? Or, maybe you have a different plan?
Answer: The distance is fine. The parallel connection is not. These batteries have a built-in BMS that can turn off the battery at any time it needs to do so to protect the cells. If one battery is off and a second one in parallel with it is still on, the state of charge of the second one will change under use. Later, when the first battery comes back on, there will be a damaging inrush of current from the most charged battery to the least charged one. That's bad for the cells and bad for the BMS. So, do not connect Li-ion batteries in parallel.
The only safe way to increase capacity of a Li-ion battery is to connect cells directly and permanently in parallel.
Comment: @DavideAndrea I didn't downvote because it's not what I want to hear. look at their web site, they sell them interconnected. So who's right, you or the company that makes them?
Comment: Why is the parallel connection not ok?
Comment: Makes no sense at all, they cell preconfigured racks of 3 and 6 parallel connected using a bus bar
Comment: @mark1234 Just because the issue is not clear to you, or this is not the answer you want to hear, is not a good reason for you to down-vote an instructive answer. Rather, I suggest you may want to read-up on the subject. There is a difference between Li-ion cells directly in parallel (good) and protected Li-ion batteries in parallel (usually bad). Batteries controlled by a central master can be made safe. But your batteries are "dumb" (no offense) and can't protect themselves from this event.
Comment: The cells are somewhat damaged each time a BMS turns back on if the SoC of the two batteries is different. There are two possibilities: 1) that manufacturers doesn't understand that or 2) that manufacturer does understand that but hopes that the user doesn't complain when the batteries do not perform as well after some time. There are techniques to avoid the damage, but they require expensive electronics, and such battery manufacturers do not implement them.


How do I move (sweep, export) my private keys from my Electrum standard wallet to a new HD wallet using Electrum?

Question: My present  wallet which I have been using to accumulate BTC (50+ utxos) is a Electrum Standard, script type is p2pkh, with seed available and the keystore type is bip32. I assume that I should now move all private keys and history to my new hardware wallet which is a Electrum Standard wallet with script type p2wpkh with no seed (except the Satochip settings show the hd wallet is seeded) bip32 and a keystore type HD (Satochip). What are the steps to safely transition to my new hardware wallet? I received this answer from Satochip.io regarding this issue which I don't fully understand.
"Regarding your software wallet, if you have an Electrum Seed (non BIP39), you won't be able to recover your information from to SW to the HW. In this case, you should send all your Bitcoin from one adress to the Hw one. If your SW seed is BIP39, you can import it to your Satochip HW and will have access to all your wallet information."
Thanks for any clarity you can provide!
Answer: Just send your bitcoins to an address in the HW.
Answer: You can export your private keys by going to the Wallet menu and selecting "Private keys" > "Export". Then, you can import your private keys into your new HD wallet by going to the "Wallet" menu and selecting "Private keys" > "Import".
Comment: My Electrum HD wallet (standard) under "Wallet" menu the 2 choices are Sweep and Export  and Export is grayed out.


Moving Folders using iCloud

Question: Can I move ENTIRE folders (Pages documents, Numbers spreadsheets, photos) to iCloud, or do I have to move each separately...documents to Pages app, spreadsheets to Numbers app and photos to iPhoto?  I have 10.7.5 OS...can I move entire Folder on new Mountain Lion OS?  Thanks.
Answer: This isn't the "supported" procedure, but there's a good chance it will work to move a large number of documents to iCloud.
You still have to move documents kind by kind, but not within particular programs.
In the Finder, select the documents (not a folder; the Pages (for instance) that are in the folder) that you want moved to iCloud.
Select Copy from the Edit menu.
Press ⌘⇧G to Go to Folder.
Type ~/Library/Mobile Documents/
If the folder com~apple~Pages exists, double-click it; if not, create it then double-click it.
Select Paste from the Edit menu.
Repeat for the different kinds of files you want to open in their respective apps via iCloud.

Moving Folders using iCloud


Resize digital clock

Question: Is there any way to make my digital clock smaller on my T-Mobile ZTE Zinger cellphone homepage?  In the widget app, it shows 3x2.  I would like to make it 1x1.  There is a white box with dots, but I can't resize it.
Comment: Not all widgets allow resizing, if you see the dots it's probably cause of the launcher that displays them by default but they cannot be moved if the widget has a fixed size. Try installing different clock apps from the Play store, making sure in the description resizable widgets are mentioned.
Comment: Many uneven sizes, like 3x2, cannot be shrunk, only enlarged. There are exceptions, but I don't think the clock is one.
Answer: As already mentioned by others in the comment that the Clock widget can't be shrinked less than 3x2 size dimensions. You can alternatively try a third party app from the Play Store. Ony such example is,
1x1 Clock widget in which you can have clock widgets in multiple sizes with the customization options available within the app. You can find the source code of this app on this GitHub link.
Or if you want analog clock, you could try Simple Analog Clock - Widget from the Playstore to create a 1x1 clock widget.

Resize digital clock


Manual numbering of Theorems

Question: I have a setup where theorems are numbered automatically. Now I want a single theorem be numbered with special number, e.g. after Theorem 2 write Theorem 2'. Is it possible?
Answer:
I can't comment yet so if some that can change this answer to a comment sees it feel free to do so.

I believe your question is a possible duplicate of How do I make a Theorem n followed by a Theorem n' ?.
You should see if this question also answers yours
Comment: It looks good but I've thought that exists easier solution...
Comment: @VolodymyrBodenchuk From my own experience in dealing with latex the assumption is that you spend most of your effort adding content and let LaTeX take care of the typesetting part. This is by design, you're not supposed to be handling that level of layout detail, that's the whole point.  Often times I find things LaTeX does that I don't like and I seek out a way to force a different behavior.  The great thing about LaTeX is that it's flexible enough to be changed, but because LaTeX does some complicated things under the hood it is not necessarily changeable in a user friendly way.

Manual numbering of Theorems


Python PYPM Install Problems

Question: I'm trying to download modules using pypm and activestate.
PYPM is installing modules to %APPDATA%\Python on Windows. The activestate website says that if I want to install to c:\python32, it wont do it then "Unless the -g option is specified":
I have tried every combo in the terminal window. What does the -g command supposed to look like?
I have tried:
-g pypm install pycrypto
 pypm -g install pycrypto
 pypm  install -g pycrypto
 pypm  install  pycrypto -g

Unless the -g option is specified, packages are not installed into
  the ActivePython installation directory. Instead, PyPM follows the PEP
  370 specification and installs packages by default in ~/.local on
  Unix and Mac and %APPDATA%\Python on Windows; and the Python
  interpreter automatically picks up the local packages. To find where
  the package was installed, use the show or files command.

What is the correct way? Is there an eaiser way to download modules (not manually)?
Answer: Use pip tool:
pip install pycrypto

Python PYPM Install Problems


creating image tag for my pictures

Question: I have 3 computers: One runs windows 10, another one runs Debian and the last one act like an NAS. I store my captured pictures to my NAS. What I would like to do more is to add a tag to each photo. I tried to do so from my Debian. I went on properties and added a tag, then I run over to my Windows 10 machine to check how it worked. But it seems it did not. Do I need to have a special program to add a tag for images?
Another strange thing is that, when I add a tag to a photo on Debian search it does not look for it.
Comment: ctrl-alt-delor thank you for correcting my question!
Answer: You need to get a clear concept of what data is stored where.  I assume your images are files, maybe in JPEG or a camera-specific RAW format. So where do the tags go?  There are some options:

A database (on the NAS?) stores the tags, and relates them to the images.  In that case, the DB must be accessible by all client machines (Debian and the other one), and they all must have software to interact with that database in the way you expect.
The tags are stored inside the image files as metadata.  Desktop search engines tend to scan all files and remember where they've found what metadata.  This memory is called cache, it's a kind of database which would reside on the individual machine.  Now if you change the tag on one machine, the other one would have to update its cache.
The tag database isentirely local to, e.g., the Debian machine.  The other machine would never see this information.

Other options are possible.
The take home message is this: When you create tags, or any kind of data, make sure you have a very precise concept of where this data is stored and which programs access the data.  When using multiple machines to access/modify that data, make sure you understand the synchronisation process.
Comment: Thanks stefan for an insight how this tagging works in the real world. I thought it is a bit easier to manage. I think I need to put tags only on one machine (NAS) and when I need to search a photo I need to look from a that same computer (NAS).

creating image tag for my pictures


Find the volume of solid of revolution given two curves?

Question: I am given two curves $y=2-x^2$ and $y=x^2$, from which the bounded region is to be rotated about $x=1$. I have drawn out the shape and see that the two parabolas intersect each other at $(-1,1)$ and $ (1,1) $. However, it seems like the equation for the radii will change at $y=1$, the points of intersection. Using the cylindrical shells method I would be integrating with respect to $x$, so I am not sure how I factor this change into my integral.
Answer: Drawing the region we are rotating is very useful. Draw also the vertical line $x=1$.
Because of what you pointed out, computing volume by Slicing is a nuisance, and Cylindrical Shells is (are?) the way to go.
Draw a thin vertical strip "at" $x$, and rotate the ppart of the strip between the two curves about the line $x=1$. The radius of the cylindrical shell is $1-x$.  The height of the shell  at $x$ is $(2-x^2)-x^2$. Now one can write down the appropriate integral, and compute.


Why is the symlink I created inside an application container to allow for external storage not working?

Question: I was trying to get around Vemedio's Instacast limitation on storage location by symlinking (ln -s) the Episodes folder in ~Library/Containers/com.vemedio.osx.Instacast/Data/Documents/Instacast to another location on another drive (which is actually internal in my Mac Pro for what it is worth...). I am wondering if Apple's sandboxing is preventing this to work... Once I open Instacast, none of the previously downloaded episodes are marked as available locally and if I try to redownload one, it seems to download the file in the background but never makes it available... Any idea?
Comment: what symlink command path are you using for the other drive exactly (anonymize if you must but include important stuff)?
Comment: `ln -s /Volumes/BigOne/Podcasts/Episodes` while I am in `/Users/kheldar/Library/Containers/com.vemedio.osx.Instacast/Data/Documents/Instacast`
Comment: Have you tried killing the link and simply creating an alias in finder instead?  Some programs only resolve one or the other depending on implementation.
Comment: After you make the link (but before launching Instacast), does the link work? That is, if you put a text file in the folder, can you see it in both places?
Comment: Yes the link works I can cd into the link and I can copy things from one to the other. However, Instacast does not see any of the linked files, which tells me it is looking for a specific file ID which I deleted when I changed the folder into a symlink... WHat do you think?
Answer: For some reason, symlinking a part of the folder inside of the Containers folder doesn't work. If you want to symlink, you have to symlink the whole folder, i.e. com.vemedio.osx.Instacast
On OS X versions that support sandboxed apps (beginning from Lion), it's sometimes impossible to symlink a sandboxed app application support files to other partition, at least, an inner portion of the folder structure.
https://gist.github.com/certainlyakey/e6729864ba3fe73f9cc1:

For example, Airmail is a sandboxed email client. I'd like to move its
settings and email db to another partition by symlinking it, but it
doesn't work with the app if I symlink an inner folder of its library
container:
cd ~/Library/Containers/it.bloop.airmail.beta7/Data/Library/Application\ Support/
ln -s /Volumes/doxx/sys/Airmail Airmail

The solution is to symlink the whole container:
cd ~/Library/Containers/
ln -s /Volumes/doxx/sys/Airmail/it.bloop.airmail it.bloop.airmail


What are these special strings called?

Question: Is there any specific name for strings of data that have well defined format ? For example URLS, domain names, IP Addresses, Email addresses, File Paths etc. are all having well defined delimiters and data formats. What are these special strings in general called ?
Comment: I would call an URL an URL, an IP address an IP address, and so on. Is that not possible, or why are you insisting on an umbrella term?
Comment: am designing some algorithms for these special strings. i need some word to collectively addressing them than specifically calling URLs, IPs etc.
Answer: Any set of strings is a (formal) language. That's probably not what you mean since you have quite specific restrictions in mind.
Many standardised string formates are defined by regular expressions what makes the respective sets of strings they admit regular languages. Note that some examples are actually finite languages (IPs).
In then end, it depends on what you mean by "well defined". Any set of strings is well-defined. Anything more will depend on the kind of specification you give, and then the language will (sort of) inherit the specification's "name".
Answer: These strings are called, if I may say, standard notations.
They are all defined in standard documents, some of which are
sometimes updated, replaced by newer ones. When the Internet is concerned, many of these documents are
produced by the Internet Engineering Task Force (IETF) under the
strange name of "Request for Comments" (RFC). The syntax is usually given by context-free grammars, sometimes extended with regular expressions, in some appropriate notation (even though these formats are often regular languages).
URLS are defined in RFC 1738 (complemented by RFC 3986)
URLs are actually a very complex, and somewhat open, format, described
syntactically in section 5 of RFC 1738.  The definition make use of
other standardized formats.
For example, Email addresses are defined by RFC 822, and this
definition is used in the definition of URls such as "mailto:xxx@yyy"
Regarding file paths, you have definitions, notations, and semantics
that are specific to operating systems. But there is also an internet
wide notation and semantics that is part of the definition of URLs in RFC 1738.
Regarding domain names, the oldest non obsolete RFC defining them is
RFC 1035. Their accepted syntax in URLs is defined in section 5 of RFC 1738.
Similarly IP addresses are currently standardized by RFC 1918 for IPv4
and RFC 2460 for IPv6, and the syntax is used for URLs.
When looking for such a definition, adding "RFC" to the keywords will
usually get you faster to the right place (when Internet is
concerned).
And in case you worry about electricity shortage, there is also a
standard format, and the corresponding RFC, to send mail by homing
pigeon. See RFC 1149.

What are these special strings called?


how the ether transfer in smart contract works?

Question: I'm trying to understand the transaction flow in the smart contract between a seller and a buyer. As far as I've looked, whatever transaction is made between the seller and buyer, the ether is stored in the contract's balance, and from there the seller has to withdraw. is there a way that seller can receive ether directly from the buyer without having to withdraw from the contract's balance?
Answer: There are two ways in which a seller can receive ether from the buyer.
The first one is the one you mentioned, via the smart contract. In this case, the smart contract might specify that ether should be transferred from one account to another if certain data is received or a certain event occurs.
The other way is when the buyer transfers the ether directly to the seller's wallet address within the Ethereum network.
Answer: The seller can receive ether directly without having to withdraw from the contract's balance if the buyer is sending ETH directly to the seller through an externally owned account (e.g. Metamask), not through smart contracts. If the seller can receive ether directly from the buyer, there is no need for the smart contract to store the balance. Smart contracts are digitized, self-executing agreements that take place of an intermediary or financial middleman using blockchain technology.
Comment: I have a ERC1155 smartcontract, where user sells the NFT's he minted, and the buyer can buy from the seller. when made purchase from buyer, the ether is sent to the smartcontract only. that's why I'm trying to figure out way to transfer ether directly to the seller


Triode and saturation region in mosfet

Question: What is the difference between the triode ( ohmic ) region and the saturation ( linear ) region in mosfet ?? It's confusing since both regions are linear but why does mosfet work as an amplifier in saturation not in triode ? Isn't triode equal to the active linear region in Bjt ? If it is not then what is the triode region and what is it used for ??
Comment: It doesn't stop being an "amplifier" it simply becomes extremely lousy as a linear amplifier. Triode is where it becomes more useful as a switch or a variable resistor.
Answer: The MOSFET triode region: -

Is equivalent to the BJT saturation region: -

The BJT active region is equivalent to the MOSFET saturation region.
For both devices, normal amplifier operation is the right hand side of each graph. In switching applications, both devices are "on" in the left hand half of the graph.
Comment: An example of naming-tyranny: For an oldfart like me, "triode" region implies the vacuum tube linear operating region, while "saturation" implies an anode dragged down to a low voltage. D'oh. Semiconductor physics is the root of these terms for MOSfets, apparently history is not.
Comment: The number of peeps that refer to the MOSFET triode region as the saturation region is certainly not zero and I've argued with one particular person on these boards but he refuses to accept. That's yet another concern @glen_geek !!
Comment: There are no free meals in life but the price here isn't too high!!
Comment: @ Andy Does a clean bit of math describe the bipolar SAT region, like the inverse parabolic describe that FET TRIODE region for long-channel FETs?
Comment: @analogsystemsrf dunno, never looked into it but it sounds like the basis for a good question if you want my opinion.
Comment: I'm new here so i didn't know i should formally accept the answers @Andy aka

Triode and saturation region in mosfet


Does the magnetic field produced by a current carrying wire, exert a magnetic force on the wire itself?

Question: I have to calculate the pressure on a current carrying wire. Since there is a pressure on the wire, there must be a force on it, which is a magnetic force. Does the magnetic field produced by the wire, exert a magnetic force on the wire itself? If this is true, why?
Comment: Maybe you are looking for this: https://physics.stackexchange.com/a/394034/291127
Comment: Is the wire straight or curved?
Comment: @JánLalinský It is a straight wire
Answer: The answer is: no.
The 'magnetic force' on the wire is due (indirectly) to magnetic Lorentz forces acting on the moving electrons in it. It is true that there will be attractive magnetic forces between electrons moving in parallel paths at different points in the wire's cross-section (for example between electrons at opposite ends of a diameter). But these forces are equal and opposite, so there will be no resultant force on these electrons taken together, and no resultant force on the wire.
It's a different story when we apply an external magnetic field with a component at right angles to the wire. The electrons will then experience forces in a direction given by $\textbf F = -e \mathbf v \times \mathbf B$, (or by Fleming's left hand rule). [The moving electrons would be forced out of the wire, were it not for 'bonding forces'  that stop them from leaving. Strictly, it is these 'bonding' forces (or their Newton's Third Law partners) that the rest of the wire experiences, rather than the magnetic Lorentz forces directly. However the magnitude of the force on the wire can be correctly calculated as the vector sum of the Lorentz forces, which is easily shown to be equal in magnitude to $F=BIL\ \sin \theta$ with the usual notation.]
Comment: Thank you for drawing attention to my sloppy wording. I've made a small correction.
Comment: Would this also be the case if it is a cylindrical conductor with thickness t and a radius of R, where t << R?
Comment: Yes indeed. The same argument applies.
Comment: @PhilipWood It might be helpful to stress in your answer that the forces are equal and opposite only in the case of a straight wire. For curved wire or wire made of non-parallel segments, this is not so and the wire can exert net macroscopic magnetic force on itself.
Answer: If the wire is straight, then no, due to axial symmetry magnetic field is just compressing the wire a little but no net force is present.
However, if the wire isn't straight, then net magnetic force due to wire on itself may be non-zero. For example, consider wire in shape of upside-down letter J, in which current flows from bottom to top.
<code>  /
 /
/
|
|
|
|
|
|
|  I
</code>
The shorter oblique segment will experience magnetic force in north-west direction from the longer vertical segment. At the same time, the longer segment will experience force in the west direction. There forces add up to net non-zero magnetic force on the wire due to itself.
Comment: From your description, I infer that north and east are towards the top and right of the diagram, respectively. Your analysis also concludes that the wire has a net force in the west-north-west direction. This is clearly incorrect, as an object cannot exert a force on itself. Another way of looking at it is to call the shorter oblique segment 'A' and the longer vertical segment 'B'. Now the sum of the force exerted by A on B and the force exerted by B on A is nonzero, violating Newton's third law of motion.
Comment: > *"This is clearly incorrect, as an object cannot exert a force on itself."* Magnetic forces in general do not obey Newton's third law of motion.
Answer:
I have to calculate the pressure on a current carrying wire. Since there is a pressure on the wire

This is not relevant to the main question, but what do you mean by "pressure"? Pressure normally means the ratio of force to area. What area would you be using here?

Does the magnetic field produced by the wire, exert a magnetic force on the wire itself?

No.
Perhaps the concept will be easier to understand in the context of gravity. For example, consider the Earth. Does the gravitational field exerted by the Earth exert a force on the Earth itself? Of course not; it is not possible for an object to exert a force on itself. This applies to all forces, including magnetic forces.
Comment: Thank you for the answer! I would be using the outside surface of the wire (which is a cylinder) as the area.
Comment: @Pi314 If you find an answer useful, please upvote it. When you calculate pressure, you should be using the area that the force is spread over. Assuming there is *some* (not yet specified) force on the wire, does it make sense to say that this force is spread over the area of the wire's surface?
Comment: Would this also be the case if it is a cylindrical conductor with thickness t and a radius of R, where t << R?
Answer: The question asks about the force that produces "the pressure on a current carrying wire", and whether this force "exert(s) a magnetic force on the wire itself".  There is most definitely a radial magnetic force that creates the pressure on the wire, as discussed in these similar questions:

"Do charge carriers in a current carrying wire experience a magnetic force due to the net magnetic field they create"
"Magnetic force in the inside of cylindrical conductor?"
"Pressure experienced due to magnetic force?"

I would flag this question as a duplicate except that the currently accepted answer correctly states that there is no net force on the wire that would cause the wire's axis to move laterally. The fact that this answer was accepted by the Original Poster suggests that the question is unclear and that the OP might actually have been asking whether there is a net transverse magnetic force on the wire.


Magento Advance Search Exact Result For Particular Attribute Value

Question: I have a magento store where i have used magento advance search on home page. Works fine. In search form there is an attribute (caliber) which is actually a text type attribute but i m showing this attribute as dropdown in fronted (Used custom query to fetch the attribute value of all the product). It's  also working fine. I want to show the exact result with this attribute value. Example : if caliber value is 9mm then only this product should show but it rather shows other products whose attribute value is 7mmX39mm  since this has 9mm as well.
I have changed search type mode from LIKE to FULLTEXT but both of mode are giving same result for me. Any help will be highly appreciated.
Answer: I have modified prepareCondition function in advanced.php page
app/code/local/Mage/CatalogSearch/Model/Resource/Advanced.php

Replaced below code
if (strlen($value) > 0) {
if (in_array($attribute->getBackendType(), array('varchar', 'text', 'static'))) {
$condition = array('like' => '%' . $value . '%'); // text search
} else {
$condition = $value;
}
}

BY
if (strlen($value) > 0) {
$condition = $value;
}

I got desire output.Thanks
Answer: I'm not 100%, but I'm reasonably sure Magento doesn't have that functionality out of the box.  If you wanted it, you'd need to make your attribute a non-text element.
If you're comfortable with custom programming in Magento, the approach I'd take (assuming a modern Magento version) is

Setup an event observer for the catalog_product_collection_load_before
Return early in the event observer method if the full action name isn't catalogsearch_advanced_result (i.e. you're not on the search results page) or there's not a value for caliber in the request
Add an explicit = filter to the collection for the value of caliber

Re: #3, the code looks something like this
$collection->addFieldToFilter('caliber', $value);

Where $value is populated from the request post.
Comment: @monojitbanik It's good form to add your solution if you asked the question and solved it yourself.
Comment: thank you for your effort. I have fixed the issue in another way.


Shall we map opportunity field with out lead field while lead conversion

Question: I stuck in a place called field mapping in lead conversion.In my organisation while lead conversion picklist(standard) called "Type" in opportunity object.But in my lead object i don't have that picklist.I create that picklist in lead object
and try to map that picklist it is not available in mapping.what are ways to achieve thiis
Answer: It has been ages since I grappled with this, but do you have to specify it at all?
If not, then you have some options. You could add the custom field to the Lead object if it makes sense to your business use case and then map it accordingly. If you leave the mapping blank, what then? Well, again you have options:

Create a workflow rule on Opportunity that sets the type based on some other criteria.
Create a process builder process on Opportunity that does this (and whatever other generated values you want all in one go).
Use an Opportunity workflow rule to assign a task to someone to review and manually set the type

You could do the above also if you create the Lead "Type" field, too. Set the workflow on Lead instead of opportunity.
There is one final option: go with code. If you don't like the way that lead conversion works at all, there are some who have created their own lead conversion algorithms with Apex. This is always an option.


test for trend in ordinal response variable

Question: I have an ordinal response variable and multiple explanatory variables-both continuous and categorical. What I'd like to do is check for any univariate trend between the the different explanatory variables and the response variable. is it reasonable to just use a logistic ordinal model for each explanatory variable as long as the proportional odds assumption is fulfilled?
Answer: That is not unreasonable.  One always has to consider whether univariable (unadjusted) analyses are informative.  For univariable analysis it is fine to just use a rank correlation coefficient.  One of the most pertinent ones for this situation, when $X$ is continuous or binary, is Somers' $D_{xy}$, which does not penalize for ties on $Y$.  You can also use Spearman's $\rho^2$ which also handles the case when $X$ is categorical by considering multiple dummy variables and computing the ordinary $R^2$ against $rank(Y)$ to obtain a scaled version of the Kruskal-Wallis test.  The R Hmisc package spearman2 function makes these easy to calculate and chart using a dot plot.
Comment: Thx for the input - What is the advantage of using Spearman's ρ2 instead of just a regular Spearman if both X and Y are ordinal? Also-is there any difference with regards to power between these and the tetrachoric correlation coefficient?
Comment: Don't know about tetrachoric correlation but the only reason I sometimes square $\rho$ is so I can handle the Kruskal-Wallis situation of multiple groups.  $\rho^{2} = R^{2}$ where $R^2$ is the ordinary multiple $R^2$ for all the dummy variables against $rank(Y)$.  If all predictors had only one degree of freedom and I keep assuming monotonicity I'd use $\rho$.


Best way to notationally indicate that a solo phrase in an instrumental section should end

Question: After writing "solo" over a part intended for one instrumentalist in a section, what's the best way to indicate that the the entire section should again begin playing?
Answer: There are a couple of standard conventions for this, depending on the instrumentation you are writing for.
The first, is just writing the word Tutti above the music where the rest of the section is to enter.
The second can be used only if there is a specific number of players in the section. For instance, in an orchestral piece with two clarinets, when the solo ends, a2 is written above where the other player is then suppose to come in. This tells the players that now two people are suppose to play. Similarly, a3 and sometimes a4 are used.
Comment: I was staying away from "tutti" due to the fact that I thought that it generally indicates that the entire ensemble should begin playing. Just to be clear, it's safe to use it sectionally as well?
Comment: @Smovies, yes, when "tutti" is written in a part, and especially after the "solo" indication, it means for the entire section to enter.
Comment: It is also possible, for winds and brass, to specify the numbers of all the players on a given staff. So, if 1st and 2nd horns are on the same staff, you could also write (1. 2.) to indicate that a solo ends.


How to repair a wire in a light switch box

Question: In attempting to install a dimmer switch, I managed to snap a wire in my light switch, by not realising when I was tightening it it was pushing on the wire. What would be the best approach to fixing it be, or would I be better calling out a professional?
Comment: If you tug gently can you get more cable in the box?
Comment: Nah, I tried that, nothing came through unfortunately
Answer: I can't see the clamp on the NM cable is it plastic or metal? If metal there is probably a screw on the outside you may be able to pull the Phillips screws(s) holding the box in place and move the box to gain access. If plastic you can break It and try, replacing the clamp with a raco "insider" it is a clamp that installs from inside the box quick and easy compared to other types. It looks to short to make a splice,  sometimes you have to open a wall when this happens hopefully you can get enough slack to splice in the box.


Xbox profile question

Question: I am trying to create a profile for my Xbox 360. It says I need a USB storage device. I bought one and I'm using it but it gives me the same response each time. What does that mean?
Answer: From the Xbox 360 USB flash drive FAQ

My USB flash drive isn't showing up at all
Have you configured your device yet?

This is the first time I'm using the USB flash drive
Your USB flash drive might not be in the proper format. Plug it into your PC, open up "My computer," right-click on the USB device,
  and select "Format." Format the USB flash drive to FAT32. Make sure to
  save any files before doing this, as formatting will erase all data on
  the USB flash drive.
I've already configured it
Try plugging in your USB flash drive after the console starts up and see if it appears. This is a very uncommon issue, but we're aware
  of it and are working to correct the issue. For now, just remember to
  plug in your USB flash drive after startup

Xbox profile question


Visual Studio 2017 Graphics Debugger - No such interface supported

Question: So i have a new set up of windows 10 Home Edition on my PC and installed VS 2017 Community Edition. When i build and run the app it runes absolutely fine. But if i use the graphics debugger i get the app open and i print screen to snapshot a frame. The window opens and it shows the following

If i choose to open that frame then i get the following error - An error occurred. Playback of your application may be incomplete(HRESULT = 0x80004002) "No such interface supported"

Does anyone have any ideas what this could be as it worked fine on my laptop and for the record. Opening a brand new Directx12 app project with the spinning cube also does this.
Answer: Please have a look for the question at here. I suppose you are using Windows version 1809 or higher.
Graphics Debugging Tool does no longer support DirectX12 after 1809. Instead, you should use the PIX for Windows in future.


Verify all Stored Procedures

Question: How can I verify all stored procedures in a SQL Server database? I need to verify if all stored procedures still work, after some tables/views etc. have been deleted or changed.
Comment: Possible answer here (worked for me): https://stackoverflow.com/questions/3027399/how-to-check-all-stored-procedure-is-ok-in-sql-server
Answer: No, there is no built-in way to do this within SQL Server. As Marian stated, you could recompile all of your procedures to be sure they're still valid, but this doesn't prove they'll still work (and don't forget that deferred name resolution makes this validation less than stellar anyway). However you can use other tools such as SQL Server Data Tools (SSDT) to help facilitate unit testing.
Just like changes to your application, if you change your schema, you need to test those changes. How automated you make your unit testing depends on the complexity of your schema, the consuming application(s), and the number of permutations possible for stored procedure outcomes (including both explicit input of different parameters or different parameter values, and implicit input such as time of day, state of the system, specific data at rest, etc.). You have to keep in mind that in some cases you will expect the stored procedure output to stay the same, but in others you will actually expect it to be different.
Some potentially helpful links (a couple culled from a question on SO geared to testing a single stored procedure):

TSQLUnit for unit tests
T.S.T. the T-SQL Test Tool
Comment: Thanks for the hints/links... I'll see if any of them can be used in my setup.
Comment: We tried to script all stored procedures and run them again in the Query window - and found a few errors (= someone have made changes to a table and not verified all the stored procedures). But the best way is probably to verify the procedures during the build process. I think it can be accomplished if we create a DB solution (in Visual Studio) with all the table structures and creates a new (empty) database every time and run the procedures agains this database.
Comment: You'll need some way to keep track of all the permutations you need to test, too. For example stored procedures (especially those with optional parameters) may behave differently depending on the parameter values. I don't think just running each stored procedure once is a very valid test.
Comment: You are absolute right... Its not a full test and it depends on how your stored procedures are created. But it was a start - until we find a better an more reliable way.
Answer: I'm not sure there's any other way to verify all of them than by really executing them with proper parameters.
Even if you try to compile all procedures again you can be using dynamic sql inside the procedures and miss runtime errors.
I'd say that you need to have a good procedures' trace before and use it after to simulate a good load.
Another idea is to really have a comprehensive suite of tests for all procedures and when doing any schema changes you execute the test suite.
Answer: Visual Studio can validate the existence of objects named in your stored procedures, if you are using VS to manage your database projects. There may be other third-party tools that can do something similar, but I've not been introduced to any.
Comment: For one, Red Gate provides SQL development tools to help you manage this (versioning, comparison, unit testing, etc).
Answer: Ok, newbie answerer here.
Using sp_refreshsqlmodule you can check individual validity inside a loop.
A user of stack overflow posted a script which does exactly that: loops through sys.objects and tries to refresh the module.
I've tested it and it works perfectly. Link here:
https://stackoverflow.com/questions/3027399/how-to-check-all-stored-procedure-is-ok-in-sql-server

Verify all Stored Procedures


Is accidental, unknowing tresspassing possible?

Question: John is hunting on public land. If John accidentally crosses an unmarked property line of which he is not aware onto Joe's property, is he trespassing?
Answer: Your question goes to a person's state of mind, which gets tricky; the intention of the law is that to be guilty of trespassing a reasonable person would need to know they had entered into or were remaining in a place they are not supposed to be. Specific requirements for what that means is going to vary by jurisdiction (closed-off area, posted signs, verbal notice, etc).

Trespass is knowingly entering another owners' property or land without permission, which encroaches on the owners' privacy or property interests (Cornell Law).

In your example, John would not be trespassing unless and until Joe asked him to leave and John refused to do so.
Comment: This triggered an interesting foray into a rabbit hole. Google provides the common definition of "enter the owner's land or property without permission" - no reference to state of mind. Missouri's definition: https://revisor.mo.gov/main/OneSection.aspx?section=569.140#:~:text=A%20person%20commits%20the%20offense,structure%20or%20upon%20real%20property says in part, "A person commits the offense of trespass in the first degree if he or she knowingly enters unlawfully or knowingly remains unlawfully in a building or inhabitable structure or upon real property."
Comment: This makes me wonder if the legal def varies state by state.
Comment: Also, the OP didn't specifically ask for the legal def, but since this is _law_.stackexchange.com, I'm inferring that's what is asked.
Answer: ORS 105.700 establishes statutory liquidated damages of $1,000 for trespassing (in addition to actual damages), as long as the land is closed and the defendant entered and remained without permission. "Closing" the land is described as:

For land through which the public has no right of way, the landowner
or agent must place a notice at each outer gate and normal point of
access to the land, including both sides of a body of water that
crosses the land wherever the body of water intersects an outer
boundary line. The notice must be placed on a post, structure or
natural object in the form of a sign or a blaze of paint

(which covers the scenario that you describe, i.e. through public land). In the situation you describe, there is probably no gate near at the boundary between the public and private land, and no normal point of access (such as a driveway).
Since John is hunting, he has likely violated ORS 164.265, a Class A misdemeanor:

A person commits the crime of criminal trespass while in possession of
a firearm who, while in possession of a firearm, enters or remains
unlawfully in or upon premises.

Note that "premises" is defined in ORS 164.205 to "include[] any building and any real property, whether privately or publicly owned". If he is hunting without a firearm, it is only a Class C misdemeanor. "Enter or remain unlawfully" is defined

(a) To enter or remain in or upon premises when the premises, at the
time of such entry or remaining, are not open to the public and when
the entrant is not otherwise licensed or privileged to do so; (b) To
fail to leave premises that are open to the public after being
lawfully directed to do so by the person in charge; (c) To enter
premises that are open to the public after being lawfully directed not
to enter the premises; or (d) To enter or remain in a motor vehicle
when the entrant is not authorized to do so

Fortunately for John, they also give a definition for "Open to the public", as

premises which by their physical nature, function, custom, usage,
notice or lack thereof or other circumstances at the time would cause
a reasonable person to believe that no permission to enter or remain
is required.

Because the land owner has not adequately notified the public that the land is closed, a reasonable person would believe that no permission is required, therefore the land is "open to the public", but only w.r.t criminal trespassing.


in outlook, can you click on a task that was referring to an email to get to the containing folder

Question: i flag and categories lots of emails,  is there anyway on the todo bar to click on a task that is really just a flagged email and find the containing folder of the email ?
Answer: Right click on the "Arranged By: Due Date" column heading and select "Folder", this will group the items by where they are stored.
Answer: Simply hover the email in the todo list and it will tell you what folder it is sat in.


Why is "living room" two words, yet "bedroom" is one word?

Question: Is there an origin difference or English reason why "living room" is two words, but "bedroom" is only one?
Comment: Both of them are really one word. The space between _living_ and _room_ is present only in writing; it's an artifact of the history of printing and has nothing to do with the English language.
Comment: Open compounds resist solidification when the resulting single orthographic word would lead to a garden-path situation (there are grooms, but no drooms).
Comment: *bedroom, bathroom, storeroom* but *living room, dining room, reading room*.
Answer: "Living room" has been in the language a while; the OED's first quote for it is from 1787. I think it hasn't become a compound word due to "living" ending in "ing". Words that end in "ing" seem to only very rarely form the first part of closed compound words.
Looking at the OED, there are over a hundred entries listed that end in "ing room" or "ing-room" but none that end in "ingroom". (If you have access to the OED, you can see this by searching for *ingroom.) The same thing can be seen if you search for living*, to find all the entries that start with "living". There are very few entries that were a single word (none of which were compound words, as far as I saw). Most entries had a space and one had a hyphen ("living-in", which as an adjective is different).


Is there a way to remove a curse without going to a healer?

Question: I really suck at removing wards so I am often cursed, usually half way through a dungeon when I can't get to a healer. Is there a way to remove the curse myself?
Comment: I need a portable Healer too... I suck at dispelling
Comment: I think the easiest way is just to quicksave before dispelling, and reload if you get a nasty curse or the loot sucks.
Answer: Sadly, no.  Curses can only be cured by Healers.  You can make a purification potion that removes most negative status effects, but it doesn't help with curses.
The manual even states:

Curse:
  A curse is a long-term negative effect that certain enemies and wards can cast on your character.
  Only a healer can remove curses


The relationship between music theory and physical phenomena

Question: The first unique overtones of a simple vibrating string form a major chord. Are there other simple physical structures that would generate other chord types?
Comment: simple physical structures that generate chord types?
Comment: The title doesn't really capture the specificity of the question, but I'm not sure how to rewrite it.  Any ideas?
Comment: @NReilingh Don't know how I missed that. :P
Answer: The vibrating string and the air column of typical instruments share the same model which will produce a major chords with the first harmonics : this is called (guess what) an "harmonic system". This means you have to look for anharmonic systems if you want something else as a major chord. Basically anything not typically used for music is anharmonic : a metal plate will have a very different harmonic structure from a vibrating string.  Percussion instruments are also a rich field in that regard (with notable exceptions such as the timbals and tablas which are built to have something close to a natural harmonic series). You generally don't get a "chord" though.
A (church) bell is an example of an anharmonic system which yet is tuned. Bells are usually tuned to have a minor third as third partial, producing a minor chord.
See for example http://members.efn.org/~qehn/global/building/bars.htm for some information about tuning aluminium bars. You'll get other sounds from different culture by researching non western instrument tuning such as the gamelan.
Comment: This is a very good answer. For completeness do you know examples of the other chord types?
Comment: essentially, any piece of metal can have its first partials tuned. Whether it is interesting or not to tune it to produce something else as a major or minor chord is probably debatable. If you have something else as a fifth for the 2nd partial you'll get somthing really weird. Ditto for the 5th partial, for which you want a major of minor third. Outside of this you have instruments with a continuous spectrum, in which by definition all chords can be heard :-) Also added info in the answer.
Answer: Not chord-related per se, but an interesting phenomenon nonetheless:
Tubular Bells (essentially metal pipes), along with some other tuned percussion such as Timpani have an interesting property in that they make our brain fill in a missing harmonic fundamental which isn't actually there.
From Wikipedia:

In tubular bells, modes 4, 5, and 6 appear to determine the strike
  tone and have frequencies in the ratios 92:112:132, or 81:121:169,
  which are close enough to the ratios 2:3:4 for the ear to consider
  them nearly harmonic and to use them as a basis for establishing a
  virtual pitch

This 'Missing' (or 'Phantom') fundamental phenomenon is an interesting effect whereby we hear an 'implied' frequency suggested by the presence of others. This is probably caused by the brain's ability to extrapolate patterns - e.g. if 200Hz, 300Hz and 400Hz tones are present then the brain may fill in the 'missing' fundamental 100Hz.
In fact, this effect is deliberately exploited in some stops of the Pipe Organ, where the effect is often referred to as a 'resultant'.  Having a physical pipe of the required length (e.g. a 64ft bass) is often impractical and to get around it we combine two frequencies and get the brain to fill in the one we actually want.
Here, the desired note is sounded along with a related frequency (often a 5th) which results in the brain hearing the fundamental which is common to both.
This doesn't sound as good as a 'true' stop would, but it's a neat trick that exploits this natural phenomenon to do the job!


Choose dll files during uninstalling a windows form application program

Question: I wrote a windows forms application using c# and created setup file.Everything works fine.
My question is; we can choose which dll and exe file should be included to setup,like that can we choose which dll should be removed or at least when we try to uninstall program, can it ask to us "if I should these ... common dll files" ?
Because when I uninstall it, it can removes common dll s with the system is currently using. So there will be a problem.
I made setup file in visual studio.
Answer: Taking this question at face value: it is very unlikely that you are actually installing DLLs that are shared by other programs.  Both the VS build system and Setup project wizards try very hard to stop you from doing this.  The only effective way to do so in .NET is to strong-name the assembly and deploy it into the GAC.  The non-GAC way is to implement the AppDomain.AssemblyResolve event.  You would have mentioned that in your question if you actually did this.
The normal deploy mode for a Winforms app is ClickOnce or an installer, like you made, or simply copying the files.  If after the install, the EXE and the DLLs it uses are in one directory then you are not sharing any DLLs.
If I guessed this wrong and you actually are sharing DLLs then by far the best solution is to stop doing this.  DLL Hell is nothing to mess with.
Answer: you may consider another packaging software like InstallShield, Visual Studio Packaging projects does not offer such kind of configuration.
Comment: actually I want programto stop me. and ask me which dll s should be removed.


WSO2 ESB- Error Handling - On Error Sequence

Question: For which are all the mediators onError Sequence works?
ex: I tried Enrich mediator it didn't work and send mediator it worked.
<inSequence onError="errorhandler" xmlns="http://ws.apache.org/ns/synapse">
<enrich>
    <source clone="true" type="custom" xpath="//Body/xs"/>
    <target action="replace" property="ORIGREQUES" type="property"/>
</enrich>

Here  given xpath is wrong. In wso2Carbon.log  got the below message.

ERROR {org.apache.synapse.mediators.elementary.EnrichMediator} -
  Specified node by xpath cannot be found.
  {org.apache.synapse.mediators.elementary.EnrichMediator}

<api xmlns="http://ws.apache.org/ns/synapse" name="addTripService" context="/trip" hostname="localhost" port="8280"> <resource methods="POST" uri-template="/add/v2" faultSequence="fault">
  <inSequence onError="errorhandler">
     <enrich>
        <source clone="true" xpath="//Body/xs"/>
        <target type="property" property="ORIGREQUES"/>
     </enrich>
     <send/>
  </inSequence>

Here getting the error message whatever I have given in Errorhandler sequence.
This means that  onError  Sequence works for send mediator and not for enrich mediator. So please let me know for which all mediators it works?
Thanks in advance.
Answer: This [1] article contains detailed description about error handling in WSO2 ESB. Go through it and you will understand how the mediators works and how to handle the errors properly.
[1] http://wso2.com/library/articles/2012/10/wso2-esb-examples-best-practises-error-handling-wso2-esb/


3d printer set up

Question: I am not very used to 3D printers and I just bought my first 3D printer today (Creality3D Ender 3). But I am unable to assemble it. The 3D printer doesn't contain instruction on how to built it which I found very weird. I searched a couple of things on the Internet and I found this website, but after some steps I couldn't read it , I didn't understand what I was reading.
Comment: What printer did you buy? Usually, the build instructions in kits are on the Micro-SD card in the parcel, if you buy a Chinese printer.
Comment: I have never linked to a Google link as this is considered very impolite, but such instructions are very easy to find, you can get them from the manufacturer website.
Answer: The website you looked at is for an entirely different printer and in general.
Your instructions are in a PDF file on the mini-SD card that came with the printer. The official Ender 3 support site is https://creality3d.cn/download/produktdatei_c0002 and it also contains the Official Assembly Instructions (to me, the lower right corner). An alternate setup instruction is in a PDF distributed by Sain Smart.

3d printer set up


Maxwell's Equations: Induction

Question: What is the reason for some writing Faraday's Induction Law as $$ \nabla \times E= -\frac{1}{c}\frac{\partial B}{\partial t} $$ versus $$ \nabla \times E= -\frac{\partial B}{\partial t} ?$$
Answer: The difference has to do with the units in which $\vec{B}$ is measured in.
In SI units Faraday's Law reads as,
$$ \nabla \times \vec{E} = - \frac{\partial \vec{B}}{\partial t} $$
In Gaussian and Heaviside-Lorentz Units it reads as,
$$ \nabla \times \vec{E} = - \frac{1}{c}\frac{\partial \vec{B}}{\partial t} $$

Basically this amounts to redifining $\vec{B}$.
$$ c\vec{B}_\text{(SI)} \equiv \vec{B}_\text{(Gaussian)}$$
Comment: Would the latter units be more formerly referred to as CGS units by chance? The particular text I have that makes reference of the latter equation typically operates in CGS units.
Answer: Argue by dimensional analysis. The force on a charged particle is usually taken to be $$\mathbf F = q(\mathbf E + \mathbf v \times \mathbf B)$$ and this defines the $\mathbf E$ and $\mathbf B$ fields. With this definition $[\mathbf E] = [c][\mathbf B]$. However you could take as definition $$\mathbf F = q(\mathbf E + \frac{\mathbf v}{c} \times \mathbf B)$$
and then since $\mathbf v/c$ is dimensionless the fields have the same dimension.
In the induction law we have a space derivative on one side and a time derivative on the other side. If the dimensions of $\mathbf E$ and $\mathbf E$ already differ by $[c] = L/T$ this is not a problem, but if you take them to have the same dimension you have to correct for it with a factor $1/c$.
Of course the adult way is to take $\mathbf E$ and $\mathbf B$ to have the same dimension and $c = 1$.

Maxwell's Equations: Induction


Mobile Redirect via ModReWrite Simple code

Question: is it possible to just use this simple code for the redirection of ALL mobile phones?
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} .*(iPad|iPhone|Mobile).*
RewriteRule .* http://website.com/ [R]

since Android and Symbian and BB have "Mobile" in their strings.
or should the UserAgents be explicitly listed out like here:
http://www.projectronin.com/blog/?p=10
thanks
Answer: If possible, redirect based on screen resolution or OS, not specific model of device. Keeping a model-specific list up to date is impossible.
Also, the above solution will always redirect them to the mobile site. Sometimes users want to use the full site on their mobile devices. For that reason, I would handle this in your site's code, not in htaccess.
Put something like this in your front controller, or a controller plug-in -- any bit of code that is executed on every page request in the non-mobile version/module of your site:
if(!isset($session->non_mobile)){ $session->non_mobile = false; }

if($_GET[non-mobile]){ $session->non_mobile = true; }

if(is_mobile_browser() && $session->non_mobile == false))
{
   header('location: http://m.yoursite.com');//redirect to mobile version
}