RoHS => tin whiskers?

Oop Doop a Poop!

I think you misunderstood the sarcasm behind that one....

However the real answer is as follows.....

All metals, irrespective of their state, liquid (molten) or solid exhibit a surface tension dependent on temperature. This surface tension will be non-linear with respect to temperature.

Tin, in its solid state has a very high surface tension but for layers exceeding some depth the relative forces within the structure reduce the effects of creep.

Also the surface is stabilised by surface oxidation. In the event that the surface oxidation is damaged and/or the layer depth is too low then the underlying tin will creep and form a wisker.

Alloying the tin with other metals will not only act to modify its melting point but also modify resulting characteristic surface tension profile over temperature.

Furthermore, selection of the alloying metal might usefully be made to 'lock' the metal structure when in its solid state and provide a more ridgid and 'active' oxidising layer.

Therefore.

i) Reduce the solid phase surface tension. ii) Provide a means of locking the crystal structure. ii) Provide a preferentially oxidising surface layer to further stabilise the structure.

It's all quite simple really.

DNA

On Thu, 08 Jun 2006 15:27:49 GMT, Rich Grise Gave us:

Before the Oklahoma event, perhaps. Now... I doubt it very seriously. That is to say "pick up" isn't as easy as you make it sound. He probably has to jump through at least ten more hoops than he had to prior to the attack. Don't think so? Just ask him. The products are controlled now.

Even basic school science experiment products which can be used for explosives are controlled now... heavily so.

On Thu, 08 Jun 2006 08:44:43 -0700, John Larkin Gave us:

As far as I am concerned, they are lucky that their heart function wasn't invaded.

On Thu, 8 Jun 2006 09:40:09 -0700, "Richard Henry" Gave us:

I would refer you all to this post and thread:

snipped-for-privacy@i40g2000cwc.googlegroups.com

"Sell chemicals, then go to jail..."

You can f****ng bet they are heavily monitored, and Greaseball's buddy CANNOT go down and buy 3 tons any time he wants.

UTTER BULLSHIT!

On 8 Jun 2006 19:35:41 +0200, David Gave us:

snip

See my link given in this thread.

The Wired article (linked from there) discusses the chilling effect on chemistry education of increasingly strict regulations on chemicals.

(For anyone not quite sure what to do with snipped-for-privacy@i40g2000cwc.googlegroups.com, go to groups.google.com, ask for an advanced search, and search by message ID.)

On Thu, 8 Jun 2006 14:50:39 -0400, Keith Gave us:

Sometimes you actually do provide a glimmer of humor to the fray.

On Thu, 8 Jun 2006 12:16:10 -0700, "Richard Henry" Gave us:

NOPE. A "blating cap" won't even explode itself. :-]

Much less anything else.

Sure. If we were discussing taking down, say, some particularly ugly art museum (I could name names) or planning to meet and mixup tons of something really noxious, I sure as hell hope the Feds wouldn't ignore us. The RCMP done good.

I don't understand this fetish with "privacy." If I do something in public that any citizen or cop could see, why not let a camera see it? And if a group has a public meeting, what's wrong with an FBI agent attending? What rights are violated, except maybe the right to be an irritable jerk?

John

privacy,

court

traffic

that

Because, given Europe's history, it is insane!!

Depends on the "authorities"; "authorities" change:

Once Europe becomes an Islamic state the laws will change accordingly to allow "the proper authorities" any access they might feel they need to rigidly enforce the proper attitude and way of thinking.

This has happened before:

The past "use case" is how the Nazi's managed to use the official records designed for another purpose entirely ("church tax" I think it was) to find and round up most of the Jews; If they did not have any official data and had to elliminate by "Jewish look" alone the holocaust would have stopped with Goebbels and maybe few thousand orthodox.

not

Very. Think "All IP network" - the sender/receiver information is in every package and must be there regardless of encryption so the legislation neatly sidesteps a nasty technical issue.

Apart from that, the really interesting information about you is in the network of people you communicate with; f.ex. how many links are incoming to you, how many outgoing and call frequencies on each decides your spot in the hierachy.

Guilt by association. Your neighbor down the street is a communist/jihadist/boogy man. Your kid talks to his kid for an hour at a time sometimes, on your phone. You've got some 'splainin to do. Cast a wide enough and loose enough net and you'll find such people with additional simultaneous inconvenient coincidences that make them look even more guilty. Maybe they lost their temper and said something that a jerk neighbor will repeat. Maybe they made an angry comment they though was anonymous in a chat room or on a blog. Maybe they were curious and went to some web sites as a result of a news report. Start with ten thousand people or a hundred thousand and you'll probably end up with a handful who are absolutely innocent but look guilty as hell.

Of course if you're afraid of that sort of thing happening, you might change your habits out of fear and to avoid suspicion. This kind of electronic monitoring could make a police state far more practical than those using humans. Part of the reason even some nominally communist countries feel more free than here is that they are still cash-based and also just don't have the technology to track every move everyone makes.

Best regards, Spehro Pefhany

You mean you wouldn't want the government to know that some of your neighbors have just purchased a ton of ammonium nitrate, are discussing strategies for terrorizing the city, and meeting with others of their ilk? Moving to more mundane matters, you wouldn't want the government to know the 24 hour whereabouts and activities of the habitually criminal, the predators, and murderers? Your so-called freedoms of privacy do not extend to your movements in public and they never have. As society becomes more complex and vulnerable to massive disruption by the few, it will be necessary to move to 100% implanted trackers.

Good points. Here are a couple of more thoughts:

I got to thinking... if they're asking this of me, then they're asking someone else -about- me. So at one time I had neighbors who were some kind of religious nuts--- church four times a week, tithed 15%, etc. I OTOH, might be out mowing the lawn on Sunday morning with a beer in my hand. If Army Intelligence asked them whether I drank to excess what do you suppose the answer would be? Whatever the subjective answer might be, it went into a database where if it was regurgitated, it came out as fact.

And you realize they could be describing your (or my) house.

GSM (and other systems probably too) has paging areas. All towers in a paging area broadcast the area number, and incoming calls for that phone are transmitted on every signaling channel on those towers.

When the phone notices better reception on a channel with a different location code, it tells the system it wants to listen to incoming calls in that paging area.

So all the network knows is the paging area. These can be pretty large:

Whenever you move to a new paging area the network obviously learns which tower is used.

There is a 'keep-alive ping' as well. Also adjustable in frequency. One operator in NL used a 30 minute interval in which the phone should say it is alive, another used a 6 hour interval. Again at this interval your location becomes known from the tower used.

Thomas

Not if it involves unacceptable levels spying on *everyone*. The police will always ask for more and more powers, and therefore will always have to be limited on a rational basis.

I'd like to see people convicted of a violent crime (armed robbery, rape, murder) or with long rap sheets of minor crimes fitted with such devices for *life*, and I think the information should be available to storekeepers, security guards, barkeeps etc. Anyone who wants to spend $100 for a receiver could know when such a lowlife was entering their place of business or home.

Best regards, Spehro Pefhany

And how should we define "unacceptable"- an extension of Learned Hand?

Haha- good one!- the catch is that many of the storekeepers, security guards, barkeeps etc. are just such lowlifes themselves:-)

The problem is not that someone sees, but that what is seen is recorded, kept forever, and correlated, and as Wes Stewart has noticed, insinuations and conclusions can be made from irrelevant or subjective data.

Never mind about laws that only apply to 'public view' - if someone decides that the secret service watching is 'public'...

Thomas