Small Arms Laser Alternatives

Question: So first to admit, I really dislike the use of laser rifles and the like to replace traditional ballistic small arms, but I still really enjoy the idea of having something that'd be able to not only introduce a significant amount of heat upon a desired target but also, optionally, add something of a kinetic force that isn't plasma. I'm thinking of taking a starwars-esque approach, something like super heated particles, perhaps even ionized but I'd hate to just rip that idea out of the lore. I've considered something akin to a heat ray but I'm not quite looking for something that'd need a concentrated continuous stream to work on something more armored than heavy leather. If it aides in the approach, I'm shooting for something of a 1920+ and fallout combination of aesthetic. Also I do have a sort of "laser" weapon concept sketched up just to aide in giving off the idea I have.
Comment: Did you know white phosphorus bullets exist in real life? Also, uranium bullets ignite on impact, at least on hard targets.
Answer: Well, there are two options that I can think of.
1. Microwave/X-Ray Laser.
As the name implies, it's basically a scaled up version of the handheld x-ray machines that dentists use.
Advantages:

Not as likely to blow up in your face as other energy weapons.
It's relatively simple (again, compared to other energy weapons), so it's more likely to appear in a post-apocalyptic scenario.
Pretty much ignores armor; the only things that can defend against it are plate metal (heavy, and the laser will still make it really hot) and Faraday Cages (impractical for wearable armor).
Provided that you have some unobtainium superconductors and super-capacitors (which are pretty much required anyway if you want energy weapons), the limiting factor on energy output is your power supply.

Downsides:

Relatively quiet (this is actually a plus from a tactical point of view, but people have come to expect "pew-pew" noises.)
Like all energy weapons, you'll need good cooling.
Backscatter. Like it or not, you're probably going to get a higher-than-optimal radiation exposure if you use this.
As @JohnO pointed out, getting x-rays to lase requires a bit of handwavium. However, this doesn't affect microwave beams, so it's still less problematic than a Star Wars-style plasma caster.

2. Magnetically contained plasma blast.
Your typical "short pulse" plasma caster, as seen on Star Wars, Stargate, and (very occasionally) Star Trek.
Advantages:

No backscatter.
The radiative heat from the plasma can leave multiple enemies with burns if they are standing close together (which is typical of mooks.)
Less time exposed when firing. While Microwave/X-Ray lasers will definitely take an enemy down, you have to hold it (relatively) on target for about a second. With an accelerated plasma weapon it's more like ballistic weapons - pull the trigger and your done.

Disadvantages:

Travel time. Unlike lasers, plasma casters don't propagate at the speed of light.
Remember what I was saying about heat? Well, it is equally effective against allies.
Extremely fiddly. Unlike lasers, the primary failure mode for a plasma caster is "violently explode in your face".
Range. Due to thermal blooming (along with several other things), plasma bolts don't go very far even when the unobtainium-based magentic containment is working.
Comment: @JohnO "X-ray almost requires a small nuke" or peeling a kilometer of stickytape in vacuum in microsecond time https://www.nature.com/articles/news.2008.1185
Comment: Might go with gamma ray lasers. X-ray almost requires a small nuke, but if you're satisfied with fringey science, hafnium might be able to do IGE (induced gamma emission), allowing for something portable enough for a rifle (or maybe more of a squad gun).
Comment: @AdrianColomitchi Yeh, now you just have to get that to lase, unless the strategy is to medical image them to death.
Answer: You actually do need a plasma weapon, but "real" plasma devices don't look or work at all like the ones in Science Fiction. There are two main threads of development - devices which create plasma at the target zone, and weapons which accelerate dense plasma "projectiles" at the target.
The first type of weapon uses high energy lasers to generate a plasma on or near the target. When lasers were first developed, it was discovered that the plasma generated by the laser heating the target material would absorb the beam, protecting the material behind it. Over the years, various techniques were developed to overcome this, until it was realized that the plasma itself could be utilised to generate effects.
Various techniques have been developed to manipulate the plasma, including ultrashort, intense applications of laser power to "explode" the plasma, or even modulating the beam to use the plasma as a sort of "speaker" to transmit messages - a sort of remote PSYOPS speaker set. There have been multiple programs to exploit these effects, you can find a survey article here: https://www.popularmechanics.com/military/research/a25091957/plasma-weapon-history/
Generally speaking, these are vehicle mounted devices, that could be carried aboard a large utility vehicle or small truck.

The more traditional device generates a plasma inside the weapon and accelerates it to the target, usually via some sort of plasma railgun. A device developed in the 1990's called MARAUDER (Magnetically accelerated ring to achieve ultrahigh directed energy and radiation) was claimed to create a plasma torid (donut shaped plasma) which on impact would release the equivalent of 5 lb of TNT. To compare, a standard hand grenade generally has 500 grams of high explosive filler. The plasma also released a lot of its energy in the form of X-rays and electromagnetic radiation.
MARAUDER was launching plasma at 3000 Km/sec, and the developed version was expected to launch plasmas at 10,000 km/sec - about 3% of the speed of light. The downside of the MARAUDER was the need for a monster capaciter bank to power the weapon - the same capacitor bank that powers the Shiva Star experimental device. This is the sort of device for defending a fortress or aboard an aircraft carrier sized warship. It isn't very clear how small such a device could be made, but with a bit of handwaving it might be possible to scale down to a 747 sized airplane.

Coaxial Plasma Railgun

Shiva Star capacitor bank
So you can develop the effects desired by using plasma devices, they just are not going to look or work like the ones you see in movies and TV.

List item
Answer: Red hot cannonballs.
source

Red hot cannonballs have a glorious history!
https://en.wikipedia.org/wiki/Heated_shot

These time-consuming methods were improved by the French, who used
specially-constructed furnaces to heat shot in their artillery
batteries at the mouth of the Rhône River in 1794. The United States
incorporated hot-shot furnaces into the design of coastal
fortifications during the construction of the Second System of
seacoast defenses just prior to the War of 1812... The chain of US
seacoast forts built between 1817 and the American Civil War, such as
Fort Macon, subsequently had one or more hot shot furnaces included as
part of their standard defenses.

Your gun shoots red hot cannonballs.  Here is the awesome thing: it is a coil gun!  You use the coils to heat the iron ball using induction as depicted above.  Then you switch the current and use the entire coil assembly to fire the hot ball!  More awesome: the gun monitors the magnetism of the iron and fires it just as it starts to become nonmagnetic (as red hot iron is wont).  This prevents damaging the gun, you know.
Benefits to red hot cannonballs.
1:  They impart kinetic energy.  Yes they do.
2:  They heat things up that they touch.
3:  You can see them flying along especially if it is dark.
4:  You can collect and reuse them.  Let them cool off a little first!
5:  If you stamp messages on your red hot cannonballs they will stay legible.  Unless they hit right on the message so best to put the same message on opposite sides of the ball.
Comment: Would it be possible to heat the projectile as it accelerated, so it left the barrel of the gun not just hot, but AS molten iron, or possibly inside an armor-piercing projectile so the molten iron would be injected into the target? Not sure how the kinetics for this would look, though, but hopefully would function like most people want plasma guns to work.
Comment: @DWKraus - I think the aerodynamics of a flying liquid would cause it to spread in flight.    Heating the interior of a shell, however, is an excellent idea.  You could easily use an induction coil to heat the lead interior of a shell to liquid while leaving the steel casing still magnetic.  Then accelerate it using the coil and steel casing.
Comment: Do you understand how MAHEM works (https://en.wikipedia.org/wiki/MAHEM and https://www.darpa.mil/program/magneto-hydrodynamic-explosive-munition ) and is it related to this effect? I THINK our weapon would maybe have a similar effect. Not sure.
Comment: I guess I was imagining the Iron in the projectile, and the head of the weapon would be a cone. When the projectile hit, the hollow cone would focus the kinetic energy of the molten iron, punch a hole, and the metal would jet in behind.
Comment: @DWKraus The problem is accelerating the red hot metal using a coil gun / solenoid type arrangement.  Red hot metal is no longer magnetic.  If you contained the molten lead in the cone tipped iron shell it would be heavier and work exactly as you describe.
Answer: SPECIALIZED AMMO FOR SHOTGUNS AND GYROJETS:
Shotguns, paintball-style guns, and gyrojet guns allow a wide variety of sizes and options for your specialty ammo.The variety of shotguns and large-barreled weapons like them are very diverse in appearance, with everything from the blunderbuss to advanced auto-shot and revolver weapons. With a clip system, you should be able to rapidly switch between ammo types for devastating results. So your guns can look super-primitive OR look like Buck Rogers swapped his pitiful beam weapon for something with real technology to it. They can be single shot to full auto.
Okay, it's not a beam weapon, but if the gun is firing a high-explosive projectile, or a really big fragmentation projectile, or even something like a paintball round filled with napalm or thermite, your battle field starts to really light up.
Poison gas can be fired in a pellet, and nerve agents are often contact agents, as are many of the nastier blistering agents like phosgene oxime.
Shotguns can fire pellets to scatter lots of projectiles, slugs to deliver heavy kinetic blows, and they even make rifled slugs to improve range and accuracy(deer hunters can often only use shotguns to hunt, but WANT high powered rifles, so the ammo is evolving to follow). Big, large-barreled guns could even load sabot depleted-uranium flechettes to deal with armored enemies, or tiny shaped charges like mini RPG projectiles can fill the same niche.
Shotgun projectiles lend themselves well to all sorts of less-lethal options like sandbags, compressed plastic rings, smoke, toxins, tear gas, etc.

At longer ranges, almost everything that can be done with shotgun shells could probably be managed with a gyrojet gun. Even the barrels of shotguns and gyrojets are similar. These are basically miniature missile launchers, and weren't developed very far because they had few advantages over conventional guns in terms of just shooting someone. But coupled to a host of specialized ammo types, and suddenly this gun becomes a super-advanced blaster, blowing up doors and firing seeker missiles that can change directions with fins mid-flight. You can have monstrous handguns if desired, firing the same projectiles as the long arms (since gyrojets have almost no recoil and velocity develops after the projectile leaves the barrel). These things LOOK like ray guns, and can bring the same intimidation factor to the field.
Scale these up, and you basically have RPG's and grenade launchers.
Comment: A Milcor grenade launcher is basically a 40mm revolver, and can be loaded with a variety of munitions, including "smart" grenades.
Answer: Highly advanced plasma pellets.
Plasma weapons in games and movies are weird. You put something at plasma levels of hot out in the open and hope it reaches its target? Even if you managed to, somehow, fire a magnetic field strong enough to keep it together along with it the contact with the air would mean it loses its deadly potential fast. So why not put it in a container instead?
To keep the "bottomless clip" idea the weapons would work as follows:

a container with pressurised gas, probably a liquid under pressure, is kept on the weapon or magazine.

The magazine stores pellets that can be filled with pressurised gas. If you really want to go far, you could claim the pellets are made from an elastic alloy (maybe a Graphenated alloy?) That swells up when filled with the (liquid)gas and forms the bullet shape. The pellets are filled just before they enter the firing chamber.

upon firing, the gas is heated to plasma hot levels. The pellet keeps the plasma together and insulates it during its travel, making sure more of the heat reaches the target. Preferably the pellet is accelerated over time in the barrel through a railgun or similar.

upon reaching the target the pellet will break on impact. Careful machining and managing of the Pellet's structure make it break almost exclusively at the impact point, this means the pressurized plasma will be released in a superheated jet. Basically it would be an alternative miniature HEAT round, which is probably one of the most appropriate names for such a plasma pellet you can imagine. HEAT rounds also use a superheated jet to basically cut through armor.

as an alternative you could use a lower-pressure plasma pellet by simply filling the pellet with less plasma. This activates a delayed-fuse mechanism in the pellet. Due to its bulletshape the pellet would get the opportunity to penetrate some armor first before the delayed impact fuse causes the pellet to rupture, causing a miniature explosion hopefully inside the target. Variations could rupture in specific ways, such as opening the nose of the pellet to create a plasmajet straight forwards, or a bunch of smaller holes could open up that would (attempt to) cut many thin lines in the flesh of the poor victim.

if you want to be really nasty, the used plasma could be a corossive/toxic/acidic/base substance once it starts cooling (or still in plasma state).
Answer: You might want to consider a railgun. With a pellet or something up the the size of a pop/soda can for a projectile moving at multiples of MACH, that's going to heat up the projectile (in atmosphere) as well as whatever it hits with a lot of friction.
Even though it would be fired "cold", as it travels through atmosphere it would heat up due to friction. By the time it got downrange a mile or more, it'd likely be very hot. There are mechanisms that happen with air turbulence that can prevent this, but regardless it's going to heat up some.
And a solid chunk of a metal hitting something else solid at MACH 3 or more is going to convert a very significant amount of that velocity into heat. Then again, with a projectile decelerating from MACH 3 in, say, 6 inches, heat is the least of your worries. The shrapnel and debris created from the impact are going to be massive.
Math
If we do some "basic" math with some "basic" numbers, we can get an idea of what I'm talking about.
If we have a 1kg slug accelerated to MACH 3 (1029 m/s), we have over 500k Joules of energy to deal with. For reference, a .357 handgun with a "standard" bore and grain load has 790 Joules of energy, which travels at 440 m/s.
https://www.calculatorsoup.com/calculators/physics/kinetic.php
https://en.wikipedia.org/wiki/Speed_of_sound
https://en.wikipedia.org/wiki/.357_Magnum
Ok, so that would be on the order of a ship or large vehicle fired weapon, so more than a soldier can easily handle. Let's scale this down a bit. Do we really need to destroy buildings with each shot? Probably not.
A 2 gram projectile at MACH 3 gives 1059 Joules, so a bit more than the .357, but is 1/4 the weight of the bullet. I'd guess that it'd be armor piercing to a pretty decent thickness, due to the tiny surface area of the projectile.
That might be too small, so let's resize it again. How about 2 ounces (56.7 grams)? That's still pretty small, but increases the power to 30k Joules. This might be the right size for a Crew Served Weapon. A mortar round can be as much as 4.14 kg or more, so the railgun rounds are significantly smaller. I can't figure out how much energy a mortar detonates with, so I don't know how that would compare. However, it would likely be enough to disable most vehicles on direct impact and would be easier to aim than a mortar.
https://fas.org/man/dod-101/sys/land/m821.htm
Answer: What about a grenade launcher, which has some kinetic force, but also releases a large chemical explosion that provides secondary kinetic energy to shrapnel upon impact?

A 40mm M32 Grenade Launcher.

Small Arms Laser Alternatives


generators of groups from exact sequence

Question: Suppose I have a middle term exact sequence of finitely generated abelian groups $G \longrightarrow H \longrightarrow K$. How do I get the generators of $H$ if I know the same for other two groups?
Comment: Take the image of the generators of $G$ and choose pullbacks of generators of $K$.
Comment: is that sufficient?
Comment: Yes. Say $g_1, g_2, \ldots, g_n \in H$ are the images of generators for $G$ and $k_1, k_2, \ldots, k_m \in H$ are pullbacks for generators for $K$. Then given $h \in H$, you can first find a word $k_{i_1} \cdots k_{i_\ell}$ so that $(k_{i_1} \cdots k_{i_\ell})^{-1} h$ is in the image of $G$ in $H$. Then you just use the generators of $G$ to knock it down to the identity.
Comment: I am assuming short exact sequence, which I just realized your question isn't assuming. I'm pretty sure in the most general case you're not going to get a finitely generated group.
Comment: how about long exact sequence $G\longrightarrow H \longrightarrow K \longrightarrow L \longrightarrow M \longrightarrow N$? Where I want to compute generators of L when I know the same for others?
Answer: The exact sequence $G \xrightarrow{f} H \xrightarrow{g} K$ gives a short exact sequence
$\DeclareMathOperator{\im}{im}$
$$0 \to \im(f) \to H \to H/\im(f) \cong \im g \to 0$$
Then $G,K$ finitely generated (f.g.) abelian groups $\implies H$ f.g. (since $\im g$ is a subgroup of $K$, hence is f.g., using only that $\mathbb{Z}$ is a Noetherian ring, and also $\im(f)$ is f.g., being a quotient of $G$. Thus $H$ is an extension of two f.g. abelian groups, hence is f.g.) Explicitly, if $\im(f) = \ker g = \langle a_1, \ldots, a_n \rangle$, $\im g = \langle b_1, \ldots, b_m \rangle$, then for any choice of lifts $c_i$ with $g(c_i) = b_i$, one has $H = \langle a_1, \ldots, a_n, c_1, \ldots, c_m \rangle$.
Indeed, for any $h \in H$, one has $g(h) = r_1g(c_1) + \ldots + r_mg(c_m)$ for some $r_i \in \mathbb{Z}$, so $g(h - r_1c_1 - \ldots - r_mc_m) = 0$, and thus $h - r_1c_1 - \ldots - r_mc_m = s_1a_1 + \ldots + s_na_n$.


Can paypal transfer to bank?

Question: When you purchase an item through PayPal that is linked to your bank account when PayPal received a refund does the refund automatically transfer from your PayPal account into your linked bank account?
Comment: Does this answer your question? [Can PayPal transfer money automatically from my bank account if I link it in PayPal?](https://money.stackexchange.com/questions/75649/can-paypal-transfer-money-automatically-from-my-bank-account-if-i-link-it-in-pay)
Comment: @MarcusD Paypal has changed their policy and practices since 2017. I have a PP account tied to a bank account, and unless I want to get a "Paypal card" I have to manually "accept" PP money into my bank account.
Answer: No it does not. A refund for a payment paid by Paypal will always go into your Paypal "Balance".
You can however then withdraw those funds back to your back account but it has to be done manually. To do this go to "Add/Withdraw Money" then "Withdraw Money" and put the amount you would like to withdraw from your Paypal balance and then select the linked bank account you want the money to go to.
Answer: Hmmm. I had a different experience with it. My purchase with PayPal was canceled and the money was refunded directly to the account via PayPal. I did not have to log into the account manually and transfer the money to the account.

Can paypal transfer to bank?


Central Administration - Should I see all sites created?

Question: When I open Central Administration am I supposed to see all the sites that have been created on my intranet?  Our Sharepoint intranet connects to the default 80 port (http://bmashpt/pages/default.aspx).  When I open the Central Administration program it opens to http://bmashpt:26272/default.aspx and I do not see any of my sites.  Is this correct and if it isn't how do I change it?
Answer: In 2007 Central Administration is broken into two main sections; Operations and Application Management.  Operations will all you to manage the farm / system level configuration.  Application management will allow you to provision and manage specific applications like your Intranet.  An application can contain one or more site collections.
If you only have one site collection then it is likely that the majority of the administration could be done at the Site Collection level on the site.  If you have 100s or 1000s of sites, then there would likely be some administration that takes place in Central Administration.
Answer: Bob - Central Admin is a "back office" area for making configuration changes for your sites -- such as search and backup to name a couple.  To see all of your sites, visit the site that is on port 80 and take the link to "View all site content".  You will have to keep drilling down to see all of your sites this way.  There is a nicer navigation pane to see all of the sites if you have MOSS 2007 and not just WSS 3.0.  After the initial configuration, you will not have to go into Central Administration very regularly.  It is normal to not see your sites from Central Admin.
Answer: Central Admin is home to administration tasks that are larger than sites. As @Mike-Oryszak said, one area (Application Management) focuses on web applications, and another (Operations) on the whole farm. It also provides navigation to your Shared Services, which may include (depending on your SharePoint edition) index and search, profiles, mysites, and more.
If you are looking in Central Administration for a list of all site collections, take a look at Application Management, and find the Site Collection List link.
Comment: He didn't mention version so I didn't want to assume MOSS w/ Search, MySites, or User profiles.  Since many companies with a simple Intranet put everything in a central site collection, there may not be much to manage in CA.
Comment: @Mike-Oryszak: Fair enough. I had given +1 for your great answer, and had only wanted to provide more information.


Cataclysm rom and Xposed

Question: First, apology if this question is already answered before, but I can't find this question after searching.
For some reason I'd like to flash Xposed but afaik most of Cataclysm update is on delta update, is there any issue if I flash Xposed and then the delta update is released and apply it?
I know I have to ask this on the rom or Xposed XDA thread, but I guess it would be convenience to ask it in here.
Thanks in advance.
Answer: It actually depends on what is being changed in the update. It may or may not affect xposed.
AFAIK Xposed works by integrating itself through patching of a framework library app_process (I am no xposed developer, so I may slightly deviate here from what actually happens).
To go in detail, every app and task is started as a "fork" (or copy in simpler words) of a base process called zygote. This is started by an /init.rc script through app_process inside /system/bin.
In other words, xposed creates an extended app_process of its own.
Ok, but what does it mean?
Simply said, unless the update provided replaces or patches out the app_process or similar to a very large extent, it will affect xposed; else it won't.
Now normally, updates have fixes to system apps and internal framework for bug fixes/new features. app_process is something which is generally not changed much by custom ROM builders and its code still highly resembles original google code (many times there isn't any change at all). So an update affecting xposed is likely rare (as its the system apps/components like systemui or framework-res that contain code for almost all extra features and are hence most common elements to get updates). Especially since its delta update, the chances of xposed being affected reduce even more.
Again, it is not a guarantee that xposed would not be affected, especially when it comes to individual modules' compatibility. As I said, it depends on what and how is being updated. Always have a backup first.

Cataclysm rom and Xposed


ContentNotes and ContentDocuments in Salesforce

Question: How can I find ParentId of ContentDocuments though I have enabled the Salesforce CRM Content?
Answer: To create a document, create a new version via the ContentVersion object without setting the ContentDocumentId. This automatically creates a parent document record. When adding a new version of the document, you must specify an existing ContentDocumentId which initiates the revision process for the document. When the latest version is published, the title, owner, and publish status fields are updated in the document.

ParentId (Object - ContentDocument) -  ID of the library that owns the
  document. Created automatically when inserting a ContentVersion via
  the API for the first time. This field is available in API version
  24.0 and later when Salesforce CRM Content is enabled.


how to : call exe from minifilter driver?

Question: I want call an exe with 2 parameters from a kernel mode driver and get back boolean (0 or 1 )result in the driver .
How to do it ?
Comment: Why do you want to do this? If we had more context on what you're trying to achieve, it might be easier to give more constructive guidance. As it is, the answer to your question is "you can't", which isn't very helpful.
Comment: @Stewart -- i have written a driver  .. which has extracted a value from IRP buffer . now based on this keyword i have to pass o fail the irp ..... so i need to communicate with the database which is not easy from kernel mode driver.............  so i am using an application or exe for doing this which will result in true or false based on which i will pass or fail the irp ......  so the linking bw the driver and the application is there to do now .............
Answer: You can't really start a user mode process from minifilter or any other kernel driver.
You may want to rethink about your design.
This thread may help you: how to create a process which will run in kernel level in windows?
Answer: To the best of my knowledge only user mode processes typically start processes. There is only one time I can think of when the Windows kernel actually starts a process entirely from kernel mode without the help of a user mode process and that is when it starts SMSS during early boot, but SMSS must be considered to be special in this context because it does not run in the context of any particular subsystem. Once CSRSS is running, all processes are started with the cooperation of a user mode process. Starting a process from kernel mode would bypass win32 and CSRSS in user mode, which would make it very unlikely that process could do anything useful. Even if it could be done, since it isn't something the kernel does by itself more than once, it seems unlikely that it would be easy to do or documented.
Answer: kernel mode - user mode communication are maintained in another way. Basically in minifilters you must use this framework for communication - FltCreateCommunicationPort/FltSendMessage/etc
read this materials
http://download.microsoft.com/download/e/b/a/eba1050f-a31d-436b-9281-92cdfeae4b45/filterdriverdeveloperguide.doc (chapter about communication)
and
http://download.microsoft.com/download/f/0/5/f05a42ce-575b-4c60-82d6-208d3754b2d6/messagesupport.ppt


What are the Legalities of Game Shows?

Question: Are game shows legal by nature or is there a catch that allows them to be legal?  Are they considered a sweepstakes?  How is one able to give away prizes without it being "gambling?"  Do the game show contestants have to agree to some sort of contract to be involved?  Is it a state by state issue?
Comment: Is this why game
Answer: Game shows are not gambling because the participants do not wager their own money. They risk the show's money only. (Also as @aroth points out in the comments, the vast majority of game shows can also use the "game of skill" defense.)
Yes. Game shows use contracts for contestants. See the following examples.

Wipeout Canada
Survivor
Comment: Also many game shows involve an element of skill, which may be another basis for a legal distinction between "game show" and "gambling".
Comment: What about tickets?  I think most game shows give away their tickets.  What if they charged for the tickets?  Would that be illegal?
Comment: @CRAIG: They can charge for tickets to attend the taping but they cannot be a means of requiring entry. Example: You cannot demand that someone buy a ticket to have a chance to enter or participate the game show. This would constitute a wager or raffle which would inherently no longer make it a game of skill. Some exceptions may be a game show held a convention which requires its own tickets. In all cases, there must be a method of free entry.
Comment: It does seem that some game shows have as at least part of their premise that those in the audience can become contestants (Let's Make a Deal, The Price is Right).  Does this mean attending must be free, or can they charge to be in the audience, and draw some number of audience members to participate?

What are the Legalities of Game Shows?


Getting Computer Specs with MS-DOS

Question: I have a laptop here that's running good old Windows 98. Instead of command prompt it has MS-DOS. Is there an equivalent to the systeminfo command for MS-DOS?
Answer: For MS-DOS msd, but it is not the full equivalent.
Comment: I agree `msd.exe` is the way to go.  It isn't the full equivalent, but it does show essentially everything that MS-DOS can see and utilize.
Answer: Create a new text file in notepad with the extension .nfo, open the file it will say it is broken ignore that, it will tell you everything about the machine.
Answer: A great system inventory tool for DOS is HWiNFO. There is also a Windows version. At one time it was a commercial program, but is now freeware.

Getting Computer Specs with MS-DOS


How do I update my Samsung Galaxy Europa?

Question: What is the latest official firmware for Samsung Galaxy Europa? I am currently on 2.2 Froyo at the moment. Can I update it using Samsung Kies, or do I need to update from somewhere else?
Answer: No, you are currently running the latest version of Android for your device without flashing a custom ROM.
If you are interested in flashing a custom ROM a port of CyanogenMod 10.1 (Android version 4.2.1 Jelly Bean) has been made for your device, all information and installation guide can be found here.


How to start/stop wind blowing at a specific frame?

Question: I am running a simulation where I have wind blowing a ball. Very simple stuff. I need the wind to stop blowing after frame 210. I did this earlier but now I can't find where I set the end frame for the wind. It was similar to the start and stop for the animation but it was specific to the wind. I am wondering now if I was seeing things. Help please! Thanks in advance.
Comment: You could keyframe *Strength* value of Wind force field making this value become 0 at some frame.
Answer: Make sure the force field is not hidden. Select the force field (wind) in the outliner or 3D view. The key frames you set will then show up in the timeline and in the Animation Editor.
Insert a keyframe with a value of zero at frame 210 to stop the wind. If you want the wind to stop abruptly set a keyframe at 209 equal to the value of the keyframe before it.


Image to a graph problem

Question: I'm trying to use MorphologicalGrpah to produce a graph, but I tried with a different graph. It does not print the exact graph. Is there a way to fix it? Is there a program where I can draw a graph by my hand and convert it to Wolfram Language?
Comment: I am commenting on the OP because this addresses comments made in the two current answers: perhaps you may consider the value that would come with learning how to produce these graphs using the Wolfram Language, rather than trying to use the methods you are currently attempting. This is, in its current state, a problem of image recognition. If you continue down this path, you may find value in training a neural network to produce your desired outcome. This too can be done with the Wolfram Language.
Answer: img = Import["https://i.stack.imgur.com/g4Z5W.png"]

We can identify the circles representing vertices and remove them and fill the spaces of removed vertices to get an image to pass to MorphologicalGraph:
img2 = Colorize @ DeleteBorderComponents @ MorphologicalComponents @ Binarize @ img

img3 = DeleteSmallComponents[img2, 500]

img4 = Binarize @ RemoveBackground @ ColorNegate @ img3

img5 = ColorNegate @ MorphologicalTransform[img4, "BoundingBoxes", Infinity]

MorphologicalGraph[img5, VertexSize -> Small]

Note: The magic number 500 in step 3 is obtained by squinting at the "Area", "Circularity"  and "Rectangularity" numbers for the 13 components of img2:
ComponentMeasurements[img2, {"Area", "Circularity", "Rectangularity"}]

Comment: Thank you. Now can I use this procedure to any graph?
Answer: If you are determined to work from the way the graph has been drawn, then you need to modify the input image to get it into a form MorphologicalGraph can work with. This is one way of doing it - the idea is to fill in the circles where the vertices are then use Thinning:
img=
Then (the value of 'r' arrived at from experiment):
With[{r = 12}, TopHatTransform[img, DiskMatrix[r]]] // Binarize // Erosion[#, 2] &;
ComponentMeasurements[%, "Mask", And[#Count > 200, .9 < #Circularity < 1.1] &, "ComponentAssociation"]//Binarize;
infill = ImageAdd[Image /@ % // Values]

Now add this back to the negation of the original image to fill in the disks:
filled = ImageAdd[ColorNegate[img] // Binarize, Dilation[infill, 3]]

Then use Thinning:
thinned = Thinning[filled]

Finally, MorphologicalGraph:
MorphologicalGraph[thinned]

Comment: @MubarakAlsaeedi no, the procedure I've shown works for the form of input image you showed, it won't generalise to "any" graph in a textbook, there are no end of ways graphs can be drawn.
Comment: Thank you. If I want to follow this procedure to other graphs, I just need to fix the "r" value? Another way to say it, can I use this procedure for any graph I see in a textbook?
Answer: As per the "Applications" section of the documentation, you can use ColorNegate:

As per your comment: if you want to get Daniel Huber's graph from your image, try
MorphologicalGraph[ColorNegate@Binarize@Erosion[i, DiskMatrix[20]]] where i is the image.
Comment: It's good, but that does not give me the desired graph. The original graph has 9 vertices, but the graph you obtained has 24 Vertex.
Comment: @MubarakAlsaeedi Why don't you draw your graph in such a way that it is compatible with `MorphologicalGraph`? Clearly, the purpose of `MorphologicalGraph` is not to recognize arbitrarily-styles hand-drawn graphs, but to extract a graph from a branching structure.
Comment: @Szabolcs I can do that, but I'm searching for a way to convert an image to a graph. I'm currently studying a textbook with lots of graphs, and I want to insert them in Mathematica so I can play with them by capturing the graph and insert it as an image and then convert them to a graph.
Answer: The circles in your drawing are recognized as branch point. Therefore, do not draw circles.
Here is an example picture:

With this pictures stored in im:
im = ColorNegate[im]
MorphologicalGraph[im]

We get the following graph:
Comment: Great, thank you. One last question, is there a way when I study graphs in mathematics textbooks, I can capture them then convert them in Mathematica without drowning them without circles?
Comment: I am using: https://duckcapture.de.softonic.com/
Comment: thank you, I'm using Mac to capture easily; what I'm searching for is software like Mathpix (a software convert equations to LaTeX), but I want a software convert image to graph.

Image to a graph problem


Xcode 11 debugger crashes on breakpoint, can't find Foundation.h

Question: My macOS app compiles and runs fine, but since switching to Xcode 11, I can no longer debug from breakpoints. The debugger always crashes with a bunch of messages like this:
warning: Swift error in scratch context: /foobar/Foo-Bridging-Header.h:14:9: note: in file included from /foobar/Foo-Bridging-Header.h:14:
#import "TPPreciseTimer.h"
    ^

error: /foobar/Timer/TPPreciseTimer.h:9:9: error: 'Foundation/Foundation.h' file not found
#import <Foundation/Foundation.h>
    ^

/foobar/Timer/TPPreciseTimer.h:9:9: note: did not find header 'Foundation.h' in framework 'Foundation' (loaded from '/System/Library/Frameworks')
#import <Foundation/Foundation.h>
    ^

error: failed to import bridging header '/foobar/Foo-Bridging-Header.h'
.
Shared Swift state for Foo has developed fatal errors and is being discarded.
REPL definitions and persistent names/types will be lost.

Message from debugger: The LLDB RPC server has crashed. The crash log is located in ~/Library/Logs/DiagnosticReports and has a prefix 'lldb-rpc-server'. Please file a bug and attach the most recent crash log.

Anyone know a workaround for something like this?
My coworkers still on Xcode 10.3 are not having this issue with the same codebase.
Comment: It's not happening anymore. Maybe Apple fixed the issue?
Answer: Same here. Removing /Users/{user}/Library/Developer/Xcode/DerivedData directory helped.


Liability as a project manager

Question: I am offering project management services to a group of people wanting to buy some property.I would like to say something like this:
"Any advice I will give to the client will either be based on the best of my knowledge or based on information from a professional advisors chosen by the client, for which I personally will not take liability."
Is this acceptable to avoid liability or is there better wording?
Comment: You may look into professional liability insurance.  Such is very cheap, I think I was paying about $100/yr for 1 million in coverage.  Even perfect wording will not prevent you from being sued, but liability will normally insulate you from many of the negatives of just someone bringing a law suit.
Comment: You may be surprised to learn that the law is generally not written with an eye toward allowing people to exempt themselves from its requirements.
Comment: Where? Laws are not the same everywhere.
Answer:
Is this acceptable to avoid liability or is there better wording?

There is not nearly enough information for assessing whether the statement precludes a finding of liability.
Consider the following issues:

The nature and scope of your contract are unclear. For instance, your
client's intent to buy real estate might have no relevance to your
role of project manager, or the latter might inevitably trigger
duties no realtor can lawfully elude. It is impossible to tell which scenario applies in your matter.
The legislation in the applicable --and unspecified-- jurisdiction(s)
might void or supersede your no-liability clause.
It is doubtful that advice "based on the best on your knowledge"
and "based on information [from a third party]" will always be
mutually exclusive.
The clause seems limited to liability for detrimental advice, thereby leaving all other sorts of liability unaddressed even if they also pertain to project management.

There is no magic, one-size-fits-all wording for addressing issues of liability.
Comment: Also, waivers of liability that extent to intentional acts, willful and wanton conduct, bad faith, or gross negligence are generally not enforceable.

Liability as a project manager


How to make Facebook automatically redirect from a page to another?

Question: If you access www.facebook.com/dell you'll be redirected to the Dell page of your country.
Can I make the same thing with my page?
Like, when you access www.facebook.com/RedPurpleSecondPage to be redirected to www.facebook.com/RedPurple without having to click anywhere?
Answer: The answer to your question is that this is not possible due to the Facebook.com domain name belonging to Facebook rather than belonging to you.
If you were the owner of the domain name then you would be able to set a redirect.


How to justify Mechanical Works doesn't involve heat variations?

Question: My professor while teaching Mechanical energy said all the mechanical works are performed at at a constant temperature and said this is the main difference between the thermodynamic work and mechanical work that thermodynamic work typically involves work and heat transfer. Taking an example of motor, so far I know, we say it cannot perform at 100% efficiency some work is converted to heat. How can we justify the statement?
Comment: I think your professor is trying to explain the difference between mechanical energy, which is kinetic and potential energy of an object as a whole, and internal energy, which is kinetic and potential energy of the molecules of an object. A temperature increase when performing mechanical work would mean some mechanical energy has been lost to internal energy.
Answer: The statement: the work done by the net force on an object is equal to the change of the kinetic energy ($E_k$) is always valid.
When the force is conservative (as gravity for example), there is a well defined conserved quantity $E = E_p + E_k$, where $E_p$ is called potential energy. And there is no temperature change involved.
But in the more general case, (as an object with an initial velocity that stops after some time due to friction with the ground), there is not that conserved quantity. It is necessary to deal with the increase of temperature of object and ground due to friction, and also the heat lost to the surroundings.
Answer: Mechanics typically deals with point particles or rigid bodies, for which the internal energy is constant, and defines work as force acting through a distance causing a change in kinetic energy.  (The change in potential energy is just a simpler way to evaluate the negative of the work done by a conservative force.)
Thermodynamics considers the change in the internal energy of a system and has a broader definition of work.  See my answer to Where is (mechanical) energy conserved?.


Is expectation value of $p^2$ equivalent to this integral?

Question: Let $\psi(x)=Ne^{iax -\frac{m^2x^2}{2} -ibt}$ and I want to compute the possibility of momentum $p$. By definition : $\langle p^2\rangle=\int_{-\infty}^{\infty}\psi^*p^2\psi dx$. Is that equivalent to $\langle p^2\rangle=\int_{-\infty}^{\infty}(p\psi^*)(p\psi) dx= \int_{-\infty}^{\infty}(p\psi)^*(p\psi) dx$?
Is there any particular reason to choose one form from another ? Maybe easier computions? And is there any extra meaning/interpretation in physics for this equivalence?
Comment: See https://physics.stackexchange.com/q/57739/
Comment: @CAF so as far as I got what you replied to that old post , am I right?
Comment: yes I had replied to that older post, hope it helps!
Answer: No it's not equivalent. $p^2 \psi$ means that you apply the momentum operator twice to $\psi$. So it would be
$-i\hbar\frac{\partial}{\partial x}(-i\hbar\frac{\partial}{\partial x}\psi)=-\hbar^2\frac{\partial^2 \psi}{\partial x^2}$
Which is not the same as
$(p\psi^*)(p\psi) = (-i\hbar\frac{\partial \psi^*}{\partial x})(-i\hbar\frac{\partial \psi}{\partial x})= -\hbar^2\frac{\partial \psi^*}{\partial x}\frac{\partial \psi}{\partial x}$
$\int_{-\infty}^{\infty}\psi^*p^2\psi dx$ means
$-\hbar^2\int_{-\infty}^{\infty}\psi^*\frac{\partial^2 \psi}{\partial x^2} dx$
Comment: yes it is true  , but some how it seems that the final results after intergration lead to the same values.. check the comment I got above


Why was Socrates put on trial and executed while Diogenes wasn't?

Question: Given that Diogenes was much more disruptive in his attempts to spread philosophy, is there any reason he wasn't sentenced as Socrates was?
Comment: It was the real Socrates who was tried, not the fictional hero from Plato's texts. There is a decent wikipedia article  The Trial of Socrates  with refs.
Answer: I would suggest it is because he didn't have active followers in large numbers until after his death.
Aristotle was subject to the same charge as Socrates at the end of his life, though he was exiled rather than killed.  So the degree of disruption, the intention to be disruptive, and the actual hostility evident all seem less important in this particular charge than the number of people affected.
(Although by some accounts, Aristotle's sentence was all about racism and revenge.  Aristotle's father was Medean in origin and Athens had gone to war against Alexander the Great -- Aristotle's family's king and his own prior student.)
Athens had very active courts, but no written laws.  In the spirit of absolute democracy, elected jurors voted on everything and their decisions were bound by no precedent.  So the number of people who directly met the offending opinions and were offended probably controlled whether your case went forward toward prosecution more than any specific definition of the crime involved.
Comment: I have the understanding that Socrates' targets ware part of the elite class in Athens. He wasn't just being  a nuisance to citizens, he was going up to politicians and generals and mocking them publicly. Basically, he pissed off people who very much held the influence to make him stand trial.
Comment: That was my idea, too.  But then someone gave me Aristotle's biography in capsule form.  The later case against Aristotle makes me question the relevance.  it seems unlikely that Aristotle was going around mocking people.  Unless you buy that Aristotle's case was all racism, that undercuts the notion that Socrates' case was mostly about tweaking the wrong noses.
Comment: It's interesting I think, that Plato was part of the aristocracy, his mother was connected to Pericles for example.
Comment: Not Pericles, Solon.
Comment: I would buy that. His disdain for material reality was much higher than Aristotle's, and that is kind of a class marker in the West. It seems to me that not having to struggle for material things makes it easier to question their ultimate value.  Like an abusive parent, (cognitive-dissonance theory says) you value the world more if it causes you both pain and pleasure in good measure than if it offers you too much more of one than the other. (Much to the confusion of non-abusive parents.)
Comment: I didn't mean to imply the psychology really works differently in the East, but that religions of non-attachment spread the range of ways one can be disdainful of material reality.  Christianity is conflicted about the value of the material world in a way that Buddhism and Hinduism do not seem to be.
Answer: To add to jobermark's answer, it has at least in part to do with the historical context: the Peloponnesian War had ended only a few years earlier, and Athens had just resumed a democratic form of government after the reign of the Thirty Tyrants. Disruption of Athenian society was not a theoretical concern, and so was taken very seriously. Philip and Alexander, on the other hand, did not need to have the same concern for Diogenes.


Why is 'sheep' the same when talking about one or more than one?

Question: I am trying to find out why sheep has the plural sheep. I have found different explanations, such as, "it is because they were seen as uncountable, as in 'a herd of sheep'", "because it comes from German, which does not have the plural 's'" and that it is because it is a neutral Old English noun which does not change in the plural. Does anyone have the right explanation?
Comment: Indeed, German does not have the plural -'s, just as English doesn't. German does have the plural -s, though.
Comment: Singular "Schaf" and plural "Schafe" in German. In Swedish both are "får".
Comment: There is the web comic [Count your sheep](http://countyoursheep.keenspot.com/), whose title is based on this fact. (It's about a single sheep which gets counted.)
Comment: Reg's criticism is based on a misreading of the OP.  It refers to "the... plural 's'" - in other words, if you look closely, it says "... 's'  " - the letter 's' is enclosed in single quotes, and the quote as a whole in double quotes.
Comment: @RegDwightѬſ道: Typically, though, as the plural of imported words, rather than home-grown ones.
Comment: I guess this is some old English declension that has been preserved in modern English. Is aircraft also an example?
Comment: No "sheepen" in German?
Answer: As the Oxford English Dictionary explains, 'The prehistoric plural *skǣpu normally lost its final vowel in Old English, so that nominative and accusative singular and plural became
identical.'
Comment: @PeterOlson: A pre-Old English plural **skǣpu* lost its vowel in Old English. (But anyway, "the prehistoric era" isn't a single thing: "prehistoric" means "before (written) history", so "the prehistoric era" ended at different times in different places.)
Comment: There was old English in the prehistoric era?
Comment: This answer is somewhat overrated.  There are lots of OE neuters with identical singular and plural forms that form regular plurals in modern English, like "land" and "thing", and in general, mod.E. treatment of plurals is far removed from OE, and the fact that something happened in OE isn't even remotely close to an adequate explanation of why it happens in mod.E.  It may of course be a *part* of the explanation.
Comment: The asterisk indicates a word or form not actually found, but of which the existence is inferred.
Comment: @PeterOlson: Something can be prehistoric if its origin is prehistoric: it can still be in use after prehistoric times. Just as a 19th-century house can still exist today.
Comment: @Kris the second +1 unupvotes the first one...
Comment: Not so long as it remains 'due'.  :-)
Answer: It is true that "sheep" comes from an Old English word that is the same in the (nominative and accusative) plural as it is in the (nominative and accusative) singular.
But this isn't the reason why "sheep" is the plural form in modern English - or if it is, it's only a small part of the explanation.
Some Old English neuters have (nom & acc) plurals identical to their (nom & acc) singulars, others don't.  For example, the OE word for "ship" is "scip" in the singular, "scipu" in the plural - whereas the word for "sheep" is "sceap" in both singular and plural.  As has been pointed out, "sceap" would originally have had a plural "sceapu", but this had been almost entirely lost in OE.
However, to that I have to say "so what?" - because "house", "land", "thing", and "tree" are all words which were identical in their OE (nom & acc) singular to their OE (nom & acc) plurals - respectively, "hus", "land", "þing", and "treow".
(And it's not as though the plural suffix of the word "ships" bears any resemblance to the "-u" of "scipu", either, does it?)
So, an invariant plural in OE rarely leads to an invariant plural in modern English.  (And yes, "hus", "land", "þing", "treow" are all neuter, too, just as "sceap" is.)
One other thing that "sheep" and "deer" have in common, apart from being OE neuters with invariant plurals, though, is that both terms describe animals, and there's a certain tendency to have invariant plurals for certain animals, especially those normally found in herds.  Of course, there are many other animals to which this doesn't apply.
We could note that "elk" is very often used as the plural of "elk" (although a regular plural "elks" exists), despite the fact "elk" was an OE masculine with a regular plural ending "-s".  "Antelope" is often (not always) used as a plural, and didn't exist in OE at all.  "Buffalo" is often (not always) used as a plural, and didn't exist in OE, and has a regular plural in Spanish and Portuguese.  Mari-Lou A points out that "fish" has long been used as a plural of itself: this usage was first attested c.1400; before then, and in OE, "fish" had had a regular plural (OE "fiscas") ("fishes" today is mainly used to denote multiple types of fish, at least in standard English).
Overall, then, the OE etymology is only a small part of the explanation.
Comment: Don't forget *fish*, for hundreds of years there was no plural form.
Comment: I have added a bit about *fish* / *fishes* (although I wanted to keep it brief).  However, I'm unsure whether "fishes" ever went out of use completely (and was revived or reinvented) or whether it was always there but became much less common (which it remains today in most contexts, although more common in AmE than in BrE, according to some sources).  "Fish" as a plural is first attested c1400.  "Fishes" appeared in the 1611 Bible.
Answer: Goose comes from an ancient Germanic word that underwent a process called "mutation" or "umlaut". When it was made plural, an /i/ or /j/ sound was added, causing the tongue to rise in preparation for making that sound, and changing the "oo" to "ee". Foot/feet and tooth/teeth show this same result. However, these changes took place thousands of years ago.
Moose is a Native American word, added to the word stock of the English language during the past four hundred years. By that time plurals were created in English simply by adding an -s or, in this case, when we are speaking of an animal used for food (deer/deer, sheep/sheep, fish/fish), no inflection at all in the plural.
Answer: This is only my assumption or theory. In German it is das Schaf (singular neuter) and die Schafe (plural). But in dialects the final e is dropped and the plural is "die Schaf". I suppose that in the dialects of Old Saxon and other dialects of Anglo-Saxon this tendency was the same. I assume that especially farmers used this kind of plural (without -s) and this habit of speaking was adopted  in the standard language. The plural without -s, i.e. singular and plural have the same form, is found with names of animals in the language of farmers, fishermen and hunters, people who use simple and often reduced language.
I can't prove this theory, but as the above posts show there is uncertainty and there are several explanations that are not very convincing. So I think it is justified to come up with another hypothesis which has some degree of plausibility.
Now, after writing this post, I've looked up what Grimm says in DWB. My view is not quite right, though I'm not far off.
Grimm says the plural of the Old High German word for sheep has the same form as the singular. Later, in Middle High German a plural with -e comes up. So it seems that English has conserved the older system, plural without any ending, so that singular and plural have the same form.


Checking if ML model is possible

Question: How can I check if a machine learning model is feasible on a given dataset? What techniques like EDA, correlation etc. can be used to judge if a model is possible i.e. data and predictor variables will give reasonably accurate forecasts or in other words there is good enough signal in predictors?
Answer: When in doubt simply build a model and test how good it is (accuracy, MSE, whatever).
If those KPIs are not up to par, think about improving the parameters, feature engineering, etc.
I find this approach to be more valuable than to spend a lot of time analyzing correlations and other classical statistical analysis.
If simple models (Regression, GLM, RandomForest, XGB) do not produce results with any sensible accuracy and you see no path to successful feature engineering then you have your answer as well.
The only downside to this approach might be a perfectly good model on the first try ;)
Comment: PCA is helpful in feature engineering and reduction. It will reduce the amount of predictors while usually improving quality. That said it doesn't tell you a lot about feasibility of the model. Cross-validating a first draft model is better for this than any other analysis. EDA will tell you whether prediction **might be possible**, validating a model will **show whether it is**.
Comment: Really helpful suggestion, agree corr analysis and EDA are time consuming. Someone suggested doing a PCA analysis which helps you quickly gauge whether model is feasible or not, what do you think of this approach?

Checking if ML model is possible


Where does the notification sound come from in OS X?

Question: I'm using El Capitan, and this happens in Yosemite as well.
Once a while I hear the notification sound, same as the sound when a new email arrive in Mail.app. But nowhere can I find where it comes from. There is no new email, or any red badge shows up in the icons in the dock or launch pad. And there is no new notification in the notification centre, and no alert appeared in the upper right corner of the screen. It appears nothing happened, except for the notification sound. How can I find what app generates it?
Comment: Do you have a web browser open to Facebook or a similar site?
Comment: @Kent Yes, but in the notifications preference of safari, I've denied all websites that asked for permission.
Comment: Since El Capitan, my Mail.app plays the mail received sound when I **send** mail :(
Comment: @Tetsujin, try uncheck "Play sounds for other mail action" in the preference.
Answer: I seems that I use filters in GMail to skip inbox, and the sound is actually come from Mail.app. As a result, no new mail arrives to the Inbox of Mail.app, but to the Archive of the Mail.app.
In the preference of Mail.app, one option is to choose "Inbox Only" for "New message notifications". But it seems that this option will not mute the new messages sound when new message arrive to other mailbox, only skip the notification alert that shows up in the upper right corner of the screen.
Answer: If you are referring to the alert sound, then it is played whenever you click or do something that is not possible. Such as a keyboard shortcut that is not available in that application. The system-wide alert sound can be changed in the System Preferences-> Sound-> Sound Effects
Comment: No. I think you mean "Funk". What I heard is called "New Messages Sound".
Comment: Do you have any Mail rules that sweep mail to trash or delete them?
Comment: Thanks. That's what I'm suspecting now. I do have some rule that automatically archive incoming mails. I just need to wait for a new one to verify that.


Mysql MariaDB replication broken

Question: I have a primary DB and two replicates. replicate1 became corrupted
when the linux server was rebooted without stopping mysqld. I want to load
replicate1 with a dump I've taken from replicate2 with the command
mysqldump --master-data --single-transaction --all-databases  --compress > full_dumpfle.sql
dump was started after replication on replicate12 was stopped with
stop slave;
as soon as the dump was initiated, I restarted replication on replicate2 with
start slave;
dump file is 50G in size.
I copied the my.cnf file from replicate4 to replicate1, keeping the server-id
from replicate1's previous my.cnf file, along with the master_user and master_password
lines.
I load the DB with
mysql < full_dumpfile.sql
I find that the load exhausts the disk, which was sufficient for replicate1
before the unfortunate reboot. I've even added 100G of disk and the load threatens
to exhaust that as well.
I truncated the slow_log table which was an enormous 128G
and dropped the main database which was another 56G, after one failed load
that nearly exhausted the available disk, about 245G is free when I begin the
second load.
All I want to do is return replicate1 to service as a replicate of the master.
Obviously the method I'm using is not working. Can anyone give me directions
on how to load the dump correctly? Not wedded to the dump, can take another.
Can even initiate replication on replicate1 from scratch, if need be, but would
rather not load the master, if I can help it.
All of this takes place on our private cloud, so keeping the load down is advisable.
All of this is on ubuntu10.04LTS and MaridDB.
Server version: 5.2.12-MariaDB-mariadb115~lucid-log
Any constructive advice would be appreciated.
Raul
Answer: I've good experiences with Percona XtraBackup. See the "How to setup a slave for replication in 6 simple steps with Xtrabackup" recipe.

Mysql MariaDB replication broken


Delete Site Collection on SharePoint 2013 (On-Prem) using CSOM

Question: I want to delete Site collection with all sub-sites using CSOM on SharePoint 2013 On-Prem. I've tried with web.DeleteObject() but its works only for sub-sites not for top level site. Pls let me know if there is any other to achieve this way by using CSOM.
Comment: You can indeed delete Site Collections via csom. However, if the Site Collections have existing sub Sites, you may see an error.
Answer: you cannot delete Site Collection using CSOM and you will have to rely on either PowerShell or Web Services. you can do it in on SharePoint-Online.

The account that accesses this Web service must be a member of the
  Farm Administrators group in the Central Administration site. By
  default, the server's local Administrators group is in the Farm
  Administrators group. To access the Admin service and its methods, set
  a Web reference to http://Server_Name:Port_Number/_vti_adm/Admin.asmx.

Source: Link
Answer: This works in SharePoint 2016
var ctx = new ClientContextWrapper(targetUrl);
var tenant = new Tenant(ctx);
var spoOperation = tenant.RemoveSite(targetUrl);
ctx.Load(spoOperation);
ctx.ExecuteQuery();

If you're in 2013, you may need some extra PowerShell steps to configure your farm - https://blogs.msdn.microsoft.com/vesku/2014/06/09/provisioning-site-collections-using-sp-app-model-in-on-premises-with-just-csom/
https://stackoverflow.com/questions/29665774/remove-site-collection-in-sharepoint-2013-using-csom#30242675


Where can I get the source files of the CD label?

Question: Where can I get the source files of this CD label
https://wiki.ubuntu.com/DIYMarketing#Current%20DIYMarketing%20content:
Answer: I don't think they're available. The finalized PDF was uploaded by Canonical's Marketing Coordinator, which means the actual production of the document was probably done through channels internal to Canonical. A professional design team does not publish its source files.
With that said, I just tried importing the PDF into Inkscape (install) and it did such a good job it practically is the source file. Definitely give it a try.
Answer: Wait a few hours/days and I'm sure you will find them at http://spreadubuntu.neomenlo.org/


What is the actual album name of Justin Timberlake's The 20/20 Experience (deluxe) album?

Question: I am confused about the actual album name, is it "The 20/20 Experience" or "The 20/20 Experience (Deluxe Version)" like how it's listed on streaming services?
Answer: The Wikipedia article about the 2013 album 'The 20/20 Experience'  has "The 20/20 Experience" as the actual title.
From the same source, the Deluxe edition and the Chinese and Japanese standard editions have two additional tracks : "Dress On" and "Body Count".
Further information about the multiple formats for this release is on Discogs


Alpha nvim not starting

Question: It has something to do with my configuration, but I can't seem to display Alpha when starting nvim.
There isn't even :Alpha when I start nvim, I have to type :lua require'alpha'.setup(require'alpha.themes.startify'.config), to be able to launch it.
This leads me to believe that I messed up somewhere in my config.
If you could please take a look to help me, here is my config.
I only have this in my packer.lua for alpha in my config.
--Plug for greet screen
use {
    'goolord/alpha-nvim',
    requires = { 'nvim-tree/nvim-web-devicons' },
    config = function ()
        require'alpha'.setup(require'alpha.themes.startify'.config)
    end
}

Answer: Writing require'alpha'.setup(require'alpha.themes.startify'.config) in my init.lua fixed the problem.

Alpha nvim not starting


Are we capable of deliberatly creating DNA from inorganic compounds?

Question: Good day
The  Miller–Urey experiment showed that organic compound can naturally form from inorganic substances. What i wish to know is this: Could we as humans deliberately create a DNA molecule starting with only inorganic substances?
Comment: Yes. You can make very many different types of organic compounds from carbon monoxide and hydrogen gas (syngas) . You then need, say, N2,  NO2,  NO or nitrates and phosphates to have all the elements you need. Not an easy thing to do though. No doubt the synthetic chemists can suggest very many other ways.
Answer: Yes we could.
It wouldn't be worth the effort since all the building blocks are available from biological sources, but if you really wanted to you could have a chemist prepare nucleotides from inorganic substances.
Commercial labs routinely build long strands of DNA from individual nucleotides. You can tell them what sequence you need and they will make it for you. There's a Wikipedia article on how it works.


Is Claims-based authentication Required for Kerberos and Excel Services?

Question: I'm trying to setup Kerberos for Excel Services + SSAS. SharePoint Web Application pool using Classic Authentication. I was wondering if it's necessary to switch it to claims-based. I've found zero information on whether claims is a must in my case. Can someone, please, shed some light on it?
Answer: If i understand your question correctly, "you have setup Kerberos authentication for Excel + SSAS in SharePoint but not in IIS Pool and wondering if its necessary to set it to claim based in IIS pool or it should work with the classic mode?"
In this case i would recommend you to have a look here. . It may help you to understand.
Comment: Chillax, thank you for the link. I've read quite a lot on this topic, but still unsure whether SharePoint Application needs to use claims or not. If it's possible - could you, please provide the answer here instead of giving a link with general information?
Answer: I dont think Claims is must go for Kerberos. In SharePoint 2013 it is by default but in SharePoint 2010 their is no such restriction.
You can use both Claims as well as Classic.
In order to Configure the ECS with Kerberos, here are the steps:

Create Excel Services service account.
Configure a service principal name (SPN) on the Excel Services
service account.
Configure Kerberos constrained delegation for Excel Services.
Start the Excel Services service instance on the Excel Services
server.
Create the Excel Services service application and application proxy
to enable web applications to process Excel Services.
Configure the location of the Excel Services trusted file and the
authentication settings.
Grant the Excel Services service account permissions on the web
application content database.

Source: How to configure Excel Services in SharePoint Server 2010 for Kerberos authentication
Comment: Thank you Waqas. Do you have hands-on experienc on configuring Kerberos for Excel Services? If so - could I contact you somehow?


Netlogon is missing?

Question: By coincidence I noticed the "Netlogon" share on a Windows 2003 server is missing. Could you please explain what Netlogon is and how can I restore it?
Comment: Is the server in question a Domain Controller?
Comment: Yeah it's active directory 2003!
Answer: It's a critical part of active directory.
Per Technet
Netlogon

HKLM\SYSTEM\CurrentControlSet\Services
Description The Netlogon subkey stores information for the Net Logon
  service.
The Net Logon service verifies logon requests, and it registers,
  authenticates, and locates domain controllers. Also, to maintain
  backward compatibility, Net Logon manages replication of the user
  account database to back up domain controllers running Windows NT 4.0
  and earlier.

Restoring depends on how it became missing.
The netlogon share is different. It's a share on domain controlers for logon sripts.

The administrative share for the scripts folder on Microsoft Windows
  NT domain controllers at %SystemRoot%\system32\repl\import\scripts.
  This share is used by the NetLogon service for the following purposes:
  Storing a default user profile for users (which must be stored in a
  subdirectory called Default User). If a user without a local profile
  on his or her workstation or a server-based roaming profile logs on,
  the default user profile is used.  Storing logon scripts (for example,
  logon.bat).  Storing system policies (ntconfig.pol or config.pol
  files).  When a client logs on to a Windows NT domain and is
  authenticated, the final step in the logon process involves connecting
  to the NetLogon share and downloading or applying any of the items in
  the preceding list.

Source
http://support.microsoft.com/kb/257338
Comment: Thanks Alan for these information but my users can logon and I believe my system is running stable! I don't how I missed it. I discovered by asking a question on server fault check this page and you will understand how I discovered http://serverfault.com/questions/298047/push-new-registry-keys-via-group-policy
Comment: See my updated answer above.

Netlogon is missing?


Implementing encryption in entity framework model classes

Question: A couple things off the top here, we're using .net core 2.0 and entity framework core, so we can't use the always encrypted columns in SQL server as it's not supported yet. I've discovered the Data Protection API for Asp.net core, and I've been trying to figure out a way to use it to encrypt a few of the fields.
I found this article on how to add encryption to selected fields (link), but it doesn't really deal with how to do the actual encryption.
So, basically, I've been trying to figure out a way to inject the Data Protection service into my model classes so I can use the Protect and Unprotect methods.
I've tried configuring our DI container (autofac) to inject it as a property, but DI doesn't seem to have anything to do with instantiating the EF objects. I also tried to set it in the OnModelCreating event of the DbContext, but that doesn't seem to work either.
Maybe someone can tell me a better way of doing this, or is my approach all wrong?
Thanks.
Answer: I know it's an old topic, but if you have migrated you solution to .NET Core 2.1 en EF Core 2.1, you can use this EntityFrameworkCore.DataEncryption library that I've developed. It is an EF Core plugin that adds support for encrypted fields in your database using built-in or custom encryption providers. For now, it only has the AesProvider for AES encryption, but more will be added soon.
To use it, it's really simple, tag your entities with the [Encrypted] attribute, and then override the OnModelCreating() method in your DbContext and call modelBuilder.UseEncryption([IEncryptionProvider]); and pass it an encryption provider.
Example:
public class UserEntity
{
    public int Id { get; set; }

    [Encrypted]
    public string Username { get; set; }

    [Encrypted]
    public string Password { get; set; }

    public int Age { get; set; }
}

public class DatabaseContext : DbContext
{
    // Get key and IV from a Base64String or any other ways.
    // You can generate a key and IV using "AesProvider.GenerateKey()"
    private readonly byte[] _encryptionKey = ...;
    private readonly byte[] _encryptionIV = ...;
    private readonly IEncryptionProvider _provider;

    public DbSet<UserEntity> Users { get; set; }

    public DatabaseContext(DbContextOptions options)
        : base(options)
    {
        this._provider = new AesProvider(this._encryptionKey, this._encryptionIV);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.UseEncryption(this._provider);
    }
}

Result when saving in database:

Then you will have encrypted fields in your database, but in your code you will be able to manipulate plain text strings.
Hope it helps.
Comment: Lets say the SYMMETRIC KEY is already on the database, and it's opened by CERTIFICATE.

How do i modify this to work with an already existing key?


what are the best Practices for developing applications using Titanium Framework targeting iPhone & Android?

Question: I am planning to develop an application using Titanium Framework for iPhone and Android. Can someone list the best practices, do's and don'ts for the development using your experience with the framework?
Answer: First of all, there's the Appcelerator guide on Titanium's best practices: https://wiki.appcelerator.org/display/guides/Mobile+Best+Practices
A working link to the Tweetanium repo is here: https://github.com/appcelerator-titans/tweetanium
Titanium is still quite a young platform and unfortunately there doesn't seem to be much of a discussion about best practices. The main reference to best practices in Titanium is Tweetanium, as @bh88 states.
http://blog.krawaller.se/ is a blog from two swedish Titanium developers who are actively thinking and discussing Titanium. They've written about Tweetanium and how it influenced their style, they also write about using Coffeescript in Titanium and they've created their own framework for Titanium: http://kraniumjs.com/
Memory Leaks: Keeping the global scope clean is important to prevent memory leaks. That's why you'll see that the tweetanium project is full of self-executing functions. Appcelerator also have a couple of videos on vimeo from their Codestrong Conference, one in which Rick Bialock explains the most common mistakes that result in Memory leaks: http://vimeo.com/29804284
Answer: this is more of a tip then anything but so far my favorite function has been the tt.os in tweetanium that handles passing of vars of functions to the correct platform.
and an example of how they use it


Clarification on Mann-Whitney-Wilcoxon Test on two to three groups

Question: Is there any way to compare two or more than three using  mann-whitney-wilcoxon test? that will also give Z and R values?
Answer: The Wilcoxon-Mann-Whitney test is for two groups. If you want to compare locations of more than two groups with a similar test, then you would usually go to the Kruskal-Wallis test.
The same thing happens with the usual tests under the normality assumption -- for a location comparison (means in that case) on two samples you have a t-test but if you have more than two samples you'd use one-way ANOVA.
The Wilcoxon-Mann-Whitney test doesn't of itself provide Z values (the Mann-Whitney statistic is $U$, while the corresponding Wilcoxon statistic is usually denoted either $W$ or $T$); one can standardize $U$ and call that $Z$, of course (and in large samples it is indeed approximately normal). Some programs will produce such a $Z$ statistic by default, but it's not inherent to the test itself.
[As I mention in comments it's not clear what you mean by "R values". Is it intended to be the proportion of times an observation from sample 1 exceeds one from sample 2?]
When you move to more than two samples, there's no longer a single comparison being made; indeed, it's not even quite the same as performing all possible pairwise comparisons (it's possible with 3 or more groups to have A>B, B>C and C>A on pairwise tests, which the K-W is not sensitive to -- See [1]).
With the Kruskal-Wallis, the usual statistic is in large samples approximately distributed as chi-squared (in the same sense that the ANOVA is F by comparison with the t-statistic in the two sample case).
So a "Z" would not normally be available. You could compute Z's for pairwise comparisons of course, but as outlined above you might have a surprising outcome in that instance (where there is a cycle of differences on pairwise comparisons; you would normally not get a significant Kruskal-Wallis in that instance).
[1] Brown, B.M. and Hettmansperger, T.P. (2002),
"Kruskal–Wallis, Multiple Comparisons and Efron Dice,"
Australian & New Zealand Journal of Statistics, Vol.44 (4), p 427-438
Comment: I think the WMW can be generalised to more than 2 classes: https://link.springer.com/content/pdf/10.1023/A:1010920819831.pdf


Is the removal of Bitcoin checkpoints considered a hard-fork?

Question: The value of DEFAULT_CHECKPOINTS_ENABLED is true and changing it will allow nodes using the default settings to accept blocks that would be currently rejected during a potential reorg. Is this change considered a hard-fork, or only changes to clearly enforced consensus rules can qualify as such?
Comment: That's a bit of a stretch. Related: https://bitcoin.stackexchange.com/a/75735/5406
Answer: A hard fork is defined as a relaxation of the consensus rules. (In contrast a soft fork is defined as a restriction of the consensus rules.) Changing the consensus rules to ignore checkpoints by default (assuming the reference client Bitcoin Core defines the consensus rules) would be a relaxation of the consensus rules and hence theoretically a hard fork. However, in reality the checkpoints that have been defined in Bitcoin Core are many years deep and the probability of a re-org back to these checkpoints is infinitesimally small (zero to a huge number of decimal places). So practically it wouldn't have any impact.
Checkpoints and assumedvalid was discussed at this London BitDevs Socratic Seminar in November 2021 on AssumeUTXO.


Missing File from Mix IDE Install Package for Windows

Question: I tried to install the Mix IDE but MSVCR120.dll is missing from the install package and it won't run. Any ideas what else I could try?
Answer: I am afraid that you have hit an issue which know about but haven't had time to fix yet.
We need to run the "Visual C++ Redistributable Packages for Visual Studio 2013" (https://www.microsoft.com/en-us/download/details.aspx?id=40784
) as part of our install process, to ensure that you get these Microsoft DLLs if you don't already have them.    We don't see this issue ourselves, because we all have Visual Studio installed.
Please can you try running this installer yourself, and report back on whether that fixed the issue?   Thanks!
Comment: I run into the same problem with missing MSVCR120.dll on a Win7-64Bit system, and Bob Summerwill answer following his link fixed my problem. (new answer, because i can't comment this)


How can one know if one's battery is damaged

Question: What are the signs of a damaged or completely drained battery for Samsung Galaxy Note II? The battery displays it is empty and yet does not charge. It does not power the phone either. Am confused
Answer: You can check the the battery status using the service menu of your android device.
You can see the current battery level there. The device suggests whether or not to change the battery.


Is a white object always white?

Question: Is a object that's white with the lights on, still white although it looks different under a different light or in total darkness?
Comment: This question is about the meaning of the word "white". It has nothing to do with actual objects. -1 and vote to close.
Answer: What makes an object white is its property to re-emit and scatter nearly all the frequencies (colours). During scattering, the directional information of the light that illuminated the object also changes; that is, the incoming light is scattered into a distribution of angles. To answer your question, an object's properties do not change if it is being illuminated by a different frequency or even if it is not illuminated at all.
While we are on the subject it is worth noting the difference between reflection and scattering. Unlike a scattering object, a reflective object preserves the incident angle. So a mirror is "white" in the sense that it re-emits nearly all the frequencies, but different from traditional white objects because it has definite scattering angles.
Comment: Just FYI, the question has been edited so as not to be a duplicate, in case you'd like to adjust your answer accordingly.
Comment: @DavidZaslavsky Thanks. I've edited it to make it suitable for the present question.
Answer: The answer depends on what you understand to be "a white object". Typically, we think an object is white if it looks white with normal illumination. Since the object doesn't change when you use a red light, or when you turn off the lights, it still is a white object. You just see it red or gray (or don't see it at all) at the moment.

Is a white object always white?


Karma for the very first birth

Question: It is explained in the Bhagavad Gita that every life is governed by deeds and actions from past life which is why some people are blessed with a silver spoon in their mouth while some suffer, which means life is pretty much predetermined. Now how will the life be determined for people in their very first birth since they have no previous birth to derive from ?
Comment: @ChinmaySarupria that is an answer to the question.
Comment: @Zanna I don't have any source so I can't post answer. But this question is already answered before but I haven't been able to find it yet.
Comment: Welcome to Hinduism SE! There is no first birth to start with. Everyone has infinite births going back in time infinitely.
Answer:
Now how will the life be determined for people in their very first birth since they have no previous birth to derive from ?

According to Vedanta, there is no first birth. The Jivatma has no beginning in the cycle of life and death.
The great Vedantic philosopher Rāmānujāchārya  has stated in his work Vedartha Sangraha, or "summary of the meaning of the Vedas," the following:

The crown of Vedas i.e., The Upanishads, which lays down the good of
the whole world, enshrines this truth: A seeker, after first acquiring
a true understanding of the individual self and the Supreme and
equipped with the performance of the duties pertaining to his station
in life, must devote himself to the meditation, worship and adoring
salutation of the blessed feet of the supreme Person. This done with
immeasurable joy leads to the attainment of the Supreme.
The
individual self is subject to beginningless nescience, which has
brought about an accumulation of karma, of the nature of both merit
and demerit. The flood of such karma causes his entry into four kinds
of bodies — heavenly, human, animal and plant beginning with that of
Brahma downwards. This ingression into bodies produces the delusion of
identity with those respective bodies (and the consequent attachments
and aversions). This delusion inevitably brings about all the fears
inherent in the state of worldly existence. The entire body of Vedanta
aims at the annihilation of these fears.......
The [Brahma Sutra] aphorisms connected with this issue are, 'Partiality and cruelty
are not to be ascribed to Brahman, because of the dependence on
karma', and 'If it be said, "There is no karma, as there was no
differentiation" we deny that supposition on the ground of
beginninglessness; it is reasonable and so found in actuality
(B.S. 2;1:35-36)'.

The Brahma Sutras, written by Rishi Vedavyasa, themselves state that the Jivatma has no beginning in samsara; there was no "first birth."

2.1.34 - Not inequality and cruelty, on account of there being regard; for so (Scripture) declares.
2.1.35 - If it be said 'not so, on account of non-distinction of deeds'; we say, 'not so, on account of beginninglessness'; this is reasonable, and it is also observed.

Ramanujacharya's commentary for Sutra 2.1.35:

But before creation the individual souls do not exist; since Scripture
teaches non-distinction 'Being only this was in the beginning.' And as
then the souls do not exist, no karman can exist, and it cannot
therefore be said that the inequality of creation depends on
karman.--Of this objection the Sûtra disposes by saying 'on account of
beginninglessness,' i.e. although the individual souls and their deeds
form an eternal stream, without a beginning, yet non-distinction of
them 'is reasonable' (i.e. may reasonably be asserted) in so far as,
previous to creation, the substance of the souls abides in a very
subtle condition, destitute of names and forms, and thus incapable of
being designated as something apart from Brahman, although in reality
then also they constitute Brahman's body only. If it were not admitted
(that the distinctions in the new creation are due to karman), it
would moreover follow that souls are requited for what they have not
done, and not requited for what they have done. The fact of the souls
being without a beginning is observed, viz., to be stated in
Scripture,'The intelligent one is not born and dies not' (Ka. Up. I,
2, 18); so also the fact of the flow of creation going on from all
eternity, 'As the creator formed sun and moon formerly.' Moreover, the
text, 'Now all this was then undeveloped. It became developed by form
and name' (Bri. Up. I, 4, 7), states merely that the names and forms
of the souls were developed, and this shows that the souls themselves
existed from the beginning. Smriti also says, 'Dost thou know both
Prakriti and the soul to be without beginning?' (Bha. Gî. XIII,
19.)--As Brahman thus differs in nature from everything else, possesses all powers, has no other motive than sport, and arranges the
diversity of the creation in accordance with the different karman of
the individual souls, Brahman alone can be the universal cause.

Summary
The Jivatma is eternal (was never created), and has always been in Samsara. According to the Vedas, the Jivatma takes birth in a body according to it's karma done in previous bodies. This implies that the soul has no first birth.
Answer: You said:

Now how will the life be determined for people in their very first birth since they have no previous birth to derive from ?

Actually, your answer lies very much in the Bhagavad-Gita itself. There is no such thing as "first birth" for a Jiva. "First birth" implies souls are created but that is not the case since every Jiva has always existed just as Bhagavan has always existed. Krishna Himself states this explicitly in the Bhagavad Gita:

It is not at all that once I did not exist, nor (that) you, nor that all these kings (did not exist at anytime). And surely it is not that all of us shall not be existing hereafter. (Bhagavad-Gita 2.12)

Sripad Ramanujacharya has tried to rearrange these words to make it more easier to comprehend in his commentary on this verse:

"I, who am, as you know, the Lord of all, in beginningless time prior to this present, did not cease to exist, that is, did certainly exist. It is not that these embodied souls like you, who are subject to (My) control, did not exist, that is, I and you, "hereafter" that is, after the present time, shall not be existing. We shall (all) be certainly existing. Even as there is no doubt in regard to the fact that I, the Supreme Self and the Lord of all, am eternal in the same manner you (i.e. you, Arjuna and these) who are (all) embodied individual souls, are also seemed to be eternal"...

Later, in Bhagavad Gita 2.20, Krishna Himself again stress on the eternal nature of the soul:

Neither is this (Self) ever born, nor does (it) ever die. It cannot be that it (i.e. this Self), having been in existence (in the past), will not be in existence again (in the future). This (Self) which is unborn, eternal, constant and ancient (as well as new), is not slain when the body is slain. (Bhagavad-Gita 2.20)

So to sum it up, there is no such thing as "first birth" for any individual jiva. Souls are never created, just like Bhagavan is never created. Bhagavan and individual Jivatmas has always existed and will be also remain to do so.
Comment: @user1232138 The Jivatma is always eternal but due to eternal, we cant say it has infinite births before. Where this Jivatma was before this Samsara etc.. even if we get answer from texts we wont be satisified because we havent realized. All these answers are found only through yogic sadhana to path of Moksha. Personally I think Jiva has its first birth in Samsara but what caused it is something we ourselves have to find the answer!
Comment: @user1232138 because when you know how you came, then exit door automatically opens. This is how one gets Moksha because secret to cross over death, is there in how we took birth!
Comment: @user1232138 Without knowing how you came to this planet Samsara, it will be difficult for one to get Moksha. This is what Agastya says.
Comment: "Neither is this (Self) ever born, nor does (it) ever die. It cannot be that it (i.e. this Self), having been in existence (in the past), will not be in existence again (in the future)."     - Then what happens on attainment of moksha. Also its hard to imagine life was there without first birth.
Comment: @user1232138 The soul gets freed from the cycle of rebirth.
Comment: "Also it's hard to imagine life was there without first birth" - Think of a number line where 10 is moksha but there are infinite numbers before 10.
Comment: Thank you Surya, the concept of moksha makes better sense to me now. However I'm still finding it hard to understand how a soul incurs bad karma if it was always present and never born. Who or what ascribes it bad karma and why? Who decides its joy or misery in manifest form? Shouldn't all souls have the same nature and meet the same fate and be joyful or miserable since they were all equal and always present?
Comment: @Akshay "Personally I think Jiva has its first birth in Samsara but what caused it is something we ourselves have to find the answer!" That's a really risky assumption to invest your time and life in.
Comment: @user1232138 That's not assumption. That's path. But you should know the method from a proper Guru. You need not leave the world and invest in it. That's why Yoga is there!
Answer: According to Sri Krishna, we are born out of the Avyakta and again with death merge with the Avyakta(Gita 2/28):

O descendant of Bharata, all beings remain unmanifest in the beginning;; they become manifest in the middle. After death they certainly become unmanifest. What lamentation can there be with regard to them? (Translation by swami Gambhirananda)

This whole creation or Maya is known to be 'Anadi' ie without any beginning.
Sri Krishna says to Arjuna (Gita, 4/5)

[The Blessed Lord said O Arjuna,] many lives of Mine have passed, and so have yours. I know them all, (but) you know not, O scorcher of enemies!

He however assures all by saying (Gita, 7/14):

Since this divine Maya of Mine which is constituted by the gunas is difficult to cross over, (therefore) those who take refuge in Me alone cross over this Maya.

(All translations by Swami Gambhirananda)

Karma for the very first birth


MTG: Interaction Narset Parter of Veils with Seizan Perverter of Truth

Question: How is the interaction between Narset, Parter of Veils with Seizan, Perverter of Truth? Does the opponent lose 2 life during the upkeep without drawing the cards?
Comment: My guess is they would draw a single card during their upkeep and skip both the second draw and the draw for their turn that is after the upkeep.
Answer: At the beginning if your opponent's upkeep, they will lose 2 life and draw 1 card. Then, during their draw step, they will draw 0 cards.
The life loss and card draw are not dependent upon each other or directly related, they are simply 2 different things that both happen when the triggered ability resolves.

101.2 When a rule or effect allows or directs something to happen, and another effect states that it can't happen, the "can't" effect takes precedence.

121.2. Cards may only be drawn one at a time. If a player is instructed to draw multiple cards, that player performs that many individual card draws.

This means that the "draw 2 cards" really means "Draw a card. Draw a card." When they get to the second "Draw a card", 101.2 kicks in and prevents them from doing that. Then, when they get to their draw step, 101.2 kicks in again and prevents that draw.
Your opponent still loses 2 life because that part of the effect is not contradicted by anything:

609.3. If an effect attempts to do something impossible, it does only as much as possible.


Alternator power factor on load and its effect on output power

Question: Almost all alternator manufacturers test the alternator at 0.8 power factor. But when installed at a site for power generation, the working power factor will be around 0.9 to 0.95, due to the power factor regulators used by the users. The manufacturers provide a data sheet that specifies how much is the maximum current at different power factors. It is observed that the current decreases as power factor improves. If so, will the output power also decrease?
         In case of a 3 phase 750KVA, 415 V,50Hz alternator, rated current is 1043 A at 0.8 pf. At unity pf,  the full load current is 835 A as per the alternator manufacturer. If so, the output power at this condition is 600KVA i.e., 600KW. Is this calculation true??
If true, does it means that we can never load 750 KW load(without over loading) on a 750 KVA DG ???
Comment: In every case you get 600kW of true power, so I guess the generator is 750kVA/600kW.
Comment: Why the manufacturers are reducing the current by 20 to 25% as power factor improves to 0.9 or unity?
Answer: Yes. The ratings essentially say that the generator is rated 1043 amps maximum and the engine is rated 600 kW plus the generator losses. The engine and generator are matched for 600 kW at 0.8 pf, 1043 A. At any other operating point, either the generator or engine is working at more or less than its rated operating point.
Answer: Yes, your calculations are correct and 600 kW is all you can draw from the generator. There is, however, a simple configuration to run the generator at optimum.

simulate this circuit – Schematic created using CircuitLab
Figure 1. Power factor correction on utility line only.
The only installations I'm familiar with have generator feed into the system after the power factor correction current transformers. This way, when running on generator, there is no current in the feed being monitored by the CT and the controller switches off all the capacitors.
Other options include powering the PF controller via an auxiliary contact of the LINE breaker. When the LINE breaker is opened the PF controller will switch off, drop its contactors and switch out the capacitors.
The final, "daft" option is to short out the CT when the BACKUP breaker is closed.