Wednesday, July 30, 2014

Reshare for the "K&J Magnetics" Blog

Why are Magnets Shaped like Horseshoes? 

Why is the horseshoe considered the symbol for a magnet?  Why were magnets made in this shape?
Why aren’t neodymium magnets made in horseshoe shapes?  Can I get a neodymium horseshoe magnet?

Google provides a quick answer to the question, but not the whole story.

Why are magnets shaped like horseshoes?  A quick search yields a number of sources that all say basically the same thing: It provides more strength.  Because there are 2 poles right next to each other, we feel more pull force to a steel surface with this arrangement.
Comparison of horseshoe and cylinder magnets stuck to a steel plate. Notice the larger, stronger magnetic field within the steel from the horseshoe. This helps provide more pull force.
This is true.  Using two poles right next to each other like this can be a great way to get a strong hold.  We've shown a few examples using neodymium magnets with opposite poles right next to each other, though not in a complete horseshoe shape.  This includes the alternating magnets of the Magnetic Knife Holder and the alternating poles of magnets used inMagnetic Spice Jars.  Even the magnet-in-a-steel-cup design of ourMounting Magnets gets more strength using this basic idea.
This really isn’t the whole answer, though.  In fact, we’d say that more pull force is not the primary reason for the U shape.  If getting 2 poles together were the only goal, why not put two disc magnets or blocks side by side, and not waste all that extra magnet material going around a large “U” shape?
A big reason for the "U" shape is to avoid demagnetization with older magnet materials.

Coercivity: How strong does a magnetic field have to be to demagnetize a permanent magnet?

Demagnetization or "BH" curves for different magnet types.
There are really several interesting measures of a magnet’s strength, not just one.  Pull force is the obvious one, but coercivity is also important.  Coercivity is the measure of how strong a magnetic field you need to demagnetize a magnet.  (We discussed this previously in our article aboutMagnet Grades.)
Early magnets made of iron would not remain magnetized for long.  These materials have a very low coercivity.  So low, in fact, that the magnet tends to demagnetize itself with its own magnetic field.
As one looks at the history of the development of newer, more powerful magnet materials, it isn't just about greater pull force strength.  It is also a history of increasing coercivity as well.  Neodymium magnets are not only stronger than other magnet types, they also have a much higher coercivity.  That's why they don't tend to slowly demagnetize over time.

Why is a horseshoe shape good for coercivity?

Three load lines are shown for different magnet shapes in free space. Taller shapes operate "above the knee" and avoid demagnetizing themselves.
Even with the limitations of early magnetic materials, there are ways to improve coercivity: the “staying-magnetized” performance.  For example, a long cylinder shape stays magnetized better than a thin disc.  This idea is commonly used with low-coercivity magnetic materials, such as iron or Alnico magnets.  For example, the magnets used in door and window alarm sensors are usually long, cylindrical Alnico magnets.
We discussed the influence of shape on magnetization in some detail in our in-depth article about Temperature and Neodymium Magnets.
A horseshoe shape is kind of like a more extreme version of a long cylinder.  It changes the load line (or Permeance Coefficient) of the magnet, so that the magnet is not tending to demagnetize itself.  A horseshoe shape is chosen so that the magnetic material can stay magnetized.  It is a high coercivity shape, of sorts.
With an earlier magnet material like Alnico, you couldn't use a thin disc shape like we can with neodymium magnets.  It would quickly demagnetize itself.
The use of a steel keeper on a horseshoe magnet is another step in improving this kind of performance.  It helps the magnet not demagnetize itself even more than without the keeper.

How to remagnetize an old horseshoe magnet

In the video below, we show how to re-magnetize a horseshoe magnet.  We’re using the HS1 Alnico magnets available in our Horseshoe Magnets section, and magnetizing them with some strong, DAA neodymium cylinder magnets.  We could also have used the larger HS2 for the same demonstration.
The electronic pole identifier can be found here: EPID.  The red and black plastic coated magnet is the handy D68PC-RB magnet.  Find other pole identifying products here.

Can K&J provide neodymium magnets in a horseshoe shape?

Neodymium magnets are strong.  They provide more pull force.  You can find a stronger magnetic field around them, compared to other types of magnets.  They also have a much higher coercivity than other magnet types.  Unlike the Alnico magnets discussed before, they generally don’t demagnetize themselves.  It’s part of what makes them so amazing.
Except for a few cases (involving high temperatures or very thin magnet shapes), neodymium magnets generally won’t demagnetize each other.
To demagnetize a neodymium magnet, you really need a stronger magnetic field than a neo magnet can provide.  The whole motivation for making magnets in a horseshoe shape (increasing coercivity) is basically irrelevant.  You just don’t need this shape.
Neodymium magnets do not need a horseshoe shape or a keeper.  In fact, they can be stored with two neodymium magnets repelling one another.  It wouldn’t demagnetize them any more than having a single magnet sitting on the shelf.
The traditional iron horseshoe magnet, so shaped to avoid demagnetization in its own demagnetizing field, is now a museum piece.

    -- J.M.D. Coey (1996). Rare-Earth Iron Permanent Magnets. Oxford Science Publications.
If you want the improved (pull-force) strength of having two poles near each other, you don’t have to resort to a horseshoe shape.  You can put two magnets side by side, or use a steel structure like our Mounting Magnets do.  Why pay for the added expense of all that unnecessary added neodymium magnet material?
We also don’t provide “U” shape neo magnets because neodymium magnet material is so hard and brittle.  A “U” shape tends to concentrate the stress in the curved part of the U.  We would end up with a lot of broken magnets!

Please, don’t tell Joe Magneato he’s obsolete!

Tuesday, July 29, 2014

dontknowmeatall comments on You can ban one item from ever existing again, and everybody would know it was you, what would you ban?

Thys yctyylly cyyld wyrk.
YDYT: Wyll, pyyply yry yppyryntly vyry ymyzyd by thys dyscyvyry. Y tryyd ty gyygly yt byt Y dydn’t fynd ynythyng. My gyyss, thyygh, ys thys:
Y fyw yyyrs ygy Y wys rysyyrchyng spyyd ryydyng bycyysy ryysyns, ynd Y fyynd syvyryl pyssybly ryysyns yf why thys hyppyns, byt my fyvyryty thyyry ys thyt wy dyn’t lyyrn wyrds by spyllyng, byt by thy wyrd ytsylf. Yf yyy thynk ybyyt yt, myny wyrds yry cymplytyly ynyqyy; yt’s hyrd ty cynfysy “pyssybylyty” yr “rypyrcyssyyn”, byt thyry’s myry thyn thyt. Wy hyvy y syt yf wyrds thyt wy ysy myry fryqyyntly thyn ythyrs, ynd wy yry myry fymylyyr wyth thysy sy, wyth symy ybvyyys yxcyptyyns, yt’s hyrd ty cynfysy thym. Thys myyns thyt whyn wy syy thym wyth thy vywyls chyngyd, yyr bryyn mytchys thy symbyls yn thy scryyn wyth thy ymmydyytyly clysyst yn yyr mymyry (lyngyygy ys yssyntyylly ydvyncyd cryptygryphy, sy thys ys vyry yysy fyr ys hymyns whyly yt wyyld tyky myllynnyy ty y cympytyr). Thys yssymptyyn ys ysyylly ryght, ynd whyn yt ysn’t wy styp ty ynylyzy yt, byt yt’s nyt ys ysyyl ys yny myght thynk byfyry tryyng yt.
TL;DR Wy yry nytyryl cryptygryphyrs.

Adam and Jamie from Mythbusters

Cool. Very cool!

Monday, July 28, 2014

What are scabs for, and is it OK to pick them? - Science Museum

Well, now I know a bit more. :)

Frustration with Bad Design

"This is not how you handle things. When you find security issues, and they don't get fixed, it's one thing to attempt to prove a point with a PEN test. It's quite another to publicly expose information. You might find yourself in trouble, and you should be in trouble. This is a violation of the professional responsibility you undertake when working for someone.

This is the type of frustration that occurs in many IT workers. I've seen more than a few people working in technology that are sure they know how to properly configure and manage an application. They know how to set up security, and they become upset with a company that doesn't do a good job of running internal systems. They know that the architecture chosen for their application will fail when a load is applied.

There are some smart people in IT, but sometimes they think they're smarter than they are. Bad design, bad decisions, mistakes, even poor security practices will occur. However it's usually not your company, and it's not your place to prove that there is a flaw in a system. It's especially true that it's not your place to prove things without having been given permission to do so. Proving a point on your own is something children do, not professionals.

When you find problems in your organization, it is your responsibility to report them. I hope you think it's your job as a professional to do the best job you can, following the best practices as we know them. It's also your decision to choose to leave a job if you can't go along with, or abide by, the decisions made by your management.

If your company has chosen poorly in their technology decisions, I understand your frustration. I've often shared it, but I'd advise you to do what I've done. State your objections and either support the chosen path or find another job."

-written by Steve Jones from

Thursday, July 24, 2014

How To Make Android Faster: What Works, And What Doesn't

Be sure to read up on their ideas..

Everyone wants their devices to run faster and scammers prey on that. Recently, a scam app named Android Defrag Pro popped up on Google Play. Android doesn’t need defragmentation, but many users installed it anyway and left positive reviews. Android isn’t like Windows and doesn’t require as much maintenance — still, there are some things you can do to make your device perform faster.
You may have heard that “Android fragmentation” is a problem, but this refers to the number of devices and versions of Android in the wild – fragmentation on Android’s file system is not a problem.

Tuesday, July 22, 2014

Planck length - Wikipedia, the free encyclopedia

A very cool visualization from Wikipedia about a "planck length":
The size of the Planck length can be visualized as follows: if a particle or dot about 0.1mm in size (which is at or near the smallest the unaided human eye can see) were magnified in size to be as large as the observable universe, then inside that universe-sized "dot", the Planck length would be roughly the size of an actual 0.1mm dot. In other words, the diameter of the observable universe is to within less than an order of magnitude, larger than a 0.1 millimeter object, roughly at or near the limits of the unaided human eye, by about the same factor (1031) as that 0.1mm object or dot is larger than the Planck length. More simply – on a logarithmic scale, a dot is halfway between the Planck length and the size of the observable universe.

Saturday, July 19, 2014

My horrifying experience with Cheese Pizza on Tor.

My day started off like normal; all excited to see what new Weird Al video was going to be released today.

Hopped onto Reddit (because we love Weird Al over there).. sure enough the first link was about his new video "First World Problems".. I think that was the name of it.. still haven't watched it yet.

Anyways, that video wouldn't load.. I'm assuming due to server load. Nice! So, I clicked on another youtube video to pass the time.. In this random video, this video/blogger guy started talking about this program Tor and how you can protect your privacy on the internet.. I think I've heard about this 'Tor' before.

Now, I am big on privacy. I believe everyone has the right to say what needs to be said without fear of reprisal from people who don't want your message to be heard. You know, Illuminati, aliens, foreign governments, bigfoot.. all standard conspiracy stuff.

So I googled "Tor", and of course found this "Tor Project".. read a bit on it. I was like, "cool! a way for people to spread information!". Installed the browser bundle pack thingy, started up a relay (I think it passes encrypted packets from one computer to the next, if I understood it correctly).

Okay, so this unnormal-firefox browser is open. Now what? Well, there was a page with a list of "onion" links.. not normal internet WWW type of links. I think they can only be used inside this Tor system. Anyways. So I scroll down the list.. most sites were described as "bitcoin this! bicoin that!".. bleh. I like bitcoins, but I can do all that on the normal web.

Scrolled down to one that said something about being an online chat website. 'DarkNet', I think the name was. Okay.. spreading information is what I'm here for, so in I clicked. Some 1995ish site loads with a crap of abbreviations at the bottom. I start clicking through posts. Most are the garden variety "down with the man!" stupid kind of crap. Like 14 years who are angry at the world but don't know how to properly express themselves kind of crap and just end up hurting innocent people and ruining [their own] lives.

Skip that crap. I'm looking for Information. I want to learn more about the world. I want to know what is really going on in this Universe.

I keep scrolling, trying different links.

Until I stumble across a post that says something like "Hey guys, check out this cheese pizza!".

Now, I see '/r/funny' pics on Reddit all the time, some are amusing, some are even enlightening. So, I click on the image filename. A new window pops up with nothing. The title says a 1x1 pixel image. I think.. that's weird. Maybe I did something wrong in this Tor browser. Oh well, I close the window and scroll down some more.

There are more people replying to the posts/threads like that. I in some posts, I see the words 'child', '13yo', and 'CP' in others. That's when it hits me..

CheesePizza == child porn. I realize in moments that "cheese pizza" has got to be slang for "child porn".

WTF! I almost viewed some child porn. I felt sick. The thought that people get off on that stuff. The thought about how abused the children who have this sick perversion intertwined into theirs lives.. The bottom of my stomach sank.

This is horrible. How can we stop these perverts.

My thoughts go to my children. I pray for their safety. If anyone ever does something like this to them.. I'll let Heaven and Hell decide your fate, but I will get you there faster you sick perverts.

OMFG, wtfing hell. I support Freedom, Education, and the free spread of Information. But not this crap. No, and hell No.

I nopenopenope out of there and close the browser.

Uninstalling this Tor relay thing and hoping to never to come back. You are not going to use my bandwidth to spread that evil, you sick bastards.

Tuesday, July 8, 2014

Say vs Mean

A Farewell to Orkut

After ten years of sparking conversations and forging connections, we have decided it's time for us to start saying goodbye to Orkut. Over the past decade, YouTube, Blogger and Google+ have taken off, with communities springing up in every corner of the world. Because the growth of these communities has outpaced Orkut's growth, we've decided to focus our energy and resources on making these other social platforms as amazing as possible for everyone who uses them.
We will shut down Orkut on September 30, 2014. Until then, there will be no impact on you, so you may have time to manage the transition. You can export your profile data, community posts and photos using Google Takeout (available until September 2016). We are preserving an archive of all public communities, which will be available online starting September 30, 2014. If you don't want your posts or name to be included in the community archive, you can remove Orkut permanently from your Google account. Please visit our Help Center for any further details.
It's been a great 10 years, and we apologize to those of you still actively using the service. We hope you will find other online communities to spark more conversations and build even more connections for the next decade and beyond.

Sunday, July 6, 2014

Introducing A Truly Innovative Altcoin: Huntercoin » CryptoCoinsNews

Introducing A Truly Innovative Altcoin: Huntercoin » CryptoCoinsNews:

'via Blog this'

What Is Huntercoin?
Huntercoin is a new altcoin that released at the beginning of February to little fanfare.  Huntercoin is based off of Namecoin and utilized a dual proof-of-work algorithm to process Huntercoin transactions with both SHA and Scrypt devices.  Huntercoin is meant to be merged mined with other altcoins and should be immune to fluctuations in hardware efficiency.
That isn’t even the most interesting part about Huntercoin mining.  Huntercoin blocks are 1 minute long, and every block releases 10 Huntercoins.  1 HUC goes to the miners each block, and 8.75 is distributed on the Huntercoin map.  The remaining 0.25 HUC goes to whichever Hunter has the crown.  The traditional mining scheme has been turned on its head by Huntercoin.  For the first time since the earliest days of Bitcoin, any individual can mine meaningful amounts of crypto without dedicated hardware.

iDrive Attempted To Mine Bitcoin with 3000 Servers

iDrive Attempted To Mine Bitcoin with 3000 Servers:

'via Blog this'


Cost of mining bitcoins
Although iDrive owns 3,000 servers, they decided to use 600 (each with a quad core processoroperating at 2.8 GHz) for their tests. Their study projected a year of mining at 100% processing power, 24 hours a day and 7 days a week with the difficulty of mining increasing linearly. They also assumed that there would be no additional charge for operating their servers constantly at full power for a whole year. iDrive pays a set rate for a certain amount of electricity which they use to power the servers. The servers usually run at about 5% of their capacity during non-peak times. However, while mining bitcoins, the servers would operate at 100% the entire time. If they paid more for the increase in the amount of electricity used, this increase in energy would naturally cost more. Also coming into play was the potential that additional server usage would wear out the servers faster, as they would be operating at a higher capacity for longer amounts of time. This could shorten their lifespan and require replacing servers more frequently, which is another added cost. Also, it is possible that they could eventually exceed their allowed electricity usage, which would result in their servers being shut down."