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From: Rich Grise on 25 Nov 2009 17:54
On Wed, 25 Nov 2009 14:09:20 -0800, whit3rd wrote:
> On Nov 24, 2:49�pm, Tim Wescott <t...(a)seemywebsite.com> wrote:
>> On Wed, 25 Nov 2009 07:51:50 +1000, Adrian Jansen wrote:
>
>> > If you consider that the relative permeability is pretty close to the
>> > ratio of total gap to total path through the magnetic material, where
>> > the total gap includes all the gaps between the magnetic particles,
>> > you quickly see that the overall permeability of any practical mix of
>> > magnetic particles and plastic is going to have a permeability of
>> > around 10-20 at most, rather than 100
>>
>> Argh.
>>
>> Need to keep thinking about this, then.
>
> Err... but packing of spheres yields packing fractions of 0.523 and up,
> and
> the 'gap' fraction would be the cube root of that, 0.803 and up. This
> isn't a killer effect.
>
> You should be able to get fine iron shot (used in some toner cartridges)
> which isn't a bad fire hazard, and mix into Bondo (auto body putty, known
> to be compatible with/bond to iron) and form some shapes easily enough.

Find a shop where they do welding and grinding and torch cutting, and drag
a magnet across the floor. (or dip a magnet into the sweepers' crud pile). ;-)

For best results, put the magnet (uWave maggie magnets work pretty good)
in a plastic bag, and retrive the shavings ("iron filings") by turning
the plastic bag inside-out.

The slag from torch-cutting is magnetic - I
think it's ferrous oxide (FeO).

Then, just mix it up with some not-too-viscous epoxy, and press it into
your form.

Good Luck!
Rich

From: Adrian Jansen on 25 Nov 2009 19:20

whit3rd wrote:
> On Nov 24, 2:49 pm, Tim Wescott <t...(a)seemywebsite.com> wrote:
>> On Wed, 25 Nov 2009 07:51:50 +1000, Adrian Jansen wrote:
>
>>> If you consider that the relative permeability is pretty close to the
>>> ratio of total gap to total path through the magnetic material, where
>>> the total gap includes all the gaps between the magnetic particles, you
>>> quickly see that the overall permeability of any practical mix of
>>> magnetic particles and plastic is going to have a permeability of around
>>> 10-20 at most, rather than 100
>> Argh.
>>
>> Need to keep thinking about this, then.
>
> Err... but packing of spheres yields packing fractions of 0.523 and
> up, and
> the 'gap' fraction would be the cube root of that, 0.803 and up. This
> isn't a killer effect.
>
> You should be able to get fine iron shot (used in some toner
> cartridges)
> which isn't a bad fire hazard, and mix into Bondo (auto body putty,
> known
> to be compatible with/bond to iron) and form some shapes easily
> enough.
>

Let Effective permeability = ue
Material permeability = u
Total length = le, the total length of the magnetic circuit
Gap length = lg, the length of the non magnetic part

Then
ue = u * le / (le + lg * (u-1))

For packing fraction of 0.8, you can say
le = 1
lg = 0.2
u = 10000 ( say for iron )

ue = 5 approx

See the problem ?

--
Regards,

Adrian Jansen adrianjansen at internode dot on dot net
Note reply address is invalid, convert address above to machine form.
From: whit3rd on 27 Nov 2009 16:47
On Nov 25, 4:20 pm, Adrian Jansen <adr...(a)qq.vv.net> wrote:
> whit3rd wro
> > Err... but packing of spheres yields packing fractions of 0.523 and
> > up, and
> > the 'gap' fraction would be the cube root of that, 0.803 and up.  This
> > isn't a killer effect.

> ue = u * le / (le + lg * (u-1))
>
> For packing fraction of 0.8, you can say
....
> ue = 5 approx

OK, I get it now. There's much higher gap sensitivity because of
the multiplier of the 'u-1' factor. It also implies that my 'average'
(arithmetic mean) on the gap is wrong, there's much more flux
at the near-contact points than predicted, so we might expect
anywhere from ue=20 to maybe ue=150.

Hotpressing of iron powder would increase the contact area
significantly, which is why powdered-iron cores work well; that
wouldn't be available in the field doing onesies, because of
the powdered-iron-burns-and-oxidizes problem.
From: Rich Grise on 27 Nov 2009 18:18
On Fri, 27 Nov 2009 13:47:36 -0800, whit3rd wrote:
> On Nov 25, 4:20�pm, Adrian Jansen <adr...(a)qq.vv.net> wrote:
>> whit3rd wro
>> > Err... but packing of spheres yields packing fractions of 0.523 and
>> > up, and
>> > the 'gap' fraction would be the cube root of that, 0.803 and up.
>> > �This isn't a killer effect.
>
>> ue = u * le / (le + lg * (u-1))
>>
>> For packing fraction of 0.8, you can say
> ...
>> ue = 5 approx
>
> OK, I get it now. There's much higher gap sensitivity because of the
> multiplier of the 'u-1' factor. It also implies that my 'average'
> (arithmetic mean) on the gap is wrong, there's much more flux at the
> near-contact points than predicted, so we might expect anywhere from
> ue=20 to maybe ue=150.
>
> Hotpressing of iron powder would increase the contact area significantly,
> which is why powdered-iron cores work well; that wouldn't be available in
> the field doing onesies, because of the powdered-iron-burns-and-oxidizes
> problem.

If you're desperate, you could fab some kind of shroud around your press,
and flood it with nitrogen or argon or maybe SF6...

Cheers!
Rich

From: iman way on 29 Nov 2009 15:56
On 24 نوفمبر, 02:05, PeterD <pet...(a)hipson.net> wrote:
> On Mon, 23 Nov 2009 13:35:38 -0600, Tim Wescott <t...(a)seemywebsite.com>
> wrote:
>
> >On Mon, 23 Nov 2009 13:55:37 -0500, PeterD wrote:
>
> >> On Mon, 23 Nov 2009 12:41:46 -0600, Tim Wescott <t...(a)seemywebsite.com>
> >> wrote:
>
> >>>A long-term back-burner project just got my attention when I found out
> >>>that Home Depot sells magnetic paint.
>
> >> Interesting! What is it called, and is there a web reference?
>
> >Searching on "magnetic paint" on the Home Depot or Rust-Oleum sites
> >should get you there.
>
> http://www.rustoleum.com/CBGProduct.asp?pid=127, nothing came up with
> the suggested search terms however.

I would be thankful if you give my article 5 minute of your value
time.

THANK YOU

Merits of Islam in the Area of Creed

1- Islam has given thorough details of the concept of Allah "God",
unlike other beliefs, which make God a tribal god or a one of three
gods, it also gives thorough, and clear details of the obligations
towards Him, towards self and towards fellow beings.112: 1. Say (O
Muhammad): He is Allâh, (the) One.

**Allâh-us-Samad (The Self-Sufficient Master, Whom all creatures need,
He neither eats nor drinks).

**.He begets not, nor was He begotten;

**And there is none co-equal or comparable unto Him."29: 22. He is
Allâh, than Whom there is Lâ ilâha illa Huwa (none has the right to be
worshipped but He) the All-Knower of the unseen and the seen (open).
He is the Most Beneficent, the Most Merciful.

**He is Allâh than Whom there is Lâ ilâha illa Huwa (none has the
right to be worshipped but He) the King, the Holy, the One Free from
all defects, the Giver of security, the Watcher over His creatures,
the All-Mighty, the Compeller, the Supreme. Glory be to Allâh! (High
is He) above all that they associate as partners with Him.

**. He is Allâh, the Creator, the Inventor of all things, the Bestower
of forms. To Him belong the Best Names . All that is in the heavens
and the earth glorify Him. And He is the All-Mighty, the All-Wise.

2- Islam clearly defines the goals of our existence and duties.51:56.
And I (Allâh) created not the jinns and humans except they should
worship Me (Alone). 2: 21. O mankind! Worship your Lord (Allâh),Who
created you and those who were before you so that you may become Al-
Muttaqûn (the pious).

3- Islam clearly defines the results of failure in doing our duties so
that we are aware of the consequences of our actions.4: 14. And
whosoever disobeys Allâh and His Messenger (Muhammad), and
transgresses His limits, He will cast him into the Fire, to abide
therein; and he shall have a disgraceful torment.

4- Islam is the only religion on earth through which the Creator is
worshipped according to His direct instructions found in His Final
Book; the Holy Qoran, unlike others who worship Him based on various
human interpretations found in so-called holy books.15: 9. Verily We:
It is We Who have sent down the Dhikr (i.e. the Qur’ân) and surely, We
will guard it (from corruption) .

5- Islam is the only religion of Allah, which He ordained on humans
since the creation of Adam until the Day of Judgment. Naturally,
having One God requires one religion only. It makes no sense to
believe in One God, and at the same time believe in a multiplicity of
religions. 3: 19. Truly, the religion with Allâh is Islâm. Those who
were given the Scripture (Jews and Christians) did not differ except,
out of mutual jealousy, after knowledge had come to them. And whoever
disbelieves in the Ayât (proofs, evidences, verses, signs,
revelations, etc.) of Allâh, then surely, Allâh is Swift in calling to
account. 16:36. And verily, We have sent among every Ummah (community,
nation) a Messenger (proclaiming): "Worship Allâh (Alone), and avoid
(or keep away from) Tâghût (all false deities, etc. i.e. do not
worship Tâghût besides Allâh). Then of them were some whom Allâh
guided and of them were some upon whom the straying was justified. So
travel through the land and see what was the end of those who denied
(the truth). 3:85.And whoever seeks a religion other than Islâm, it
will never be accepted of him, and in the Hereafter he will be one of
the losers.

6- Islam’s simplicity and clarity enables all various intellect levels
of people to understand it, and subsequently embrace it without any
hesitation or uncertainty.2: 285. The Messenger (Muhammad) believes in
what has been sent down to him from his Lord, and (so do) the
believers. Each one believes in Allâh, His Angels, His Books, and His
Messengers. They say,We make no distinction between one another of His
Messengers" – and they say, "We hear, and we obey. (We seek) Your
Forgiveness, our Lord, and to You is the return (of all)." 6:151. Say
(O Muhammad): Come, I will recite what your Lord has prohibited you
from: Join not anything in worship with Him; be good and dutiful to
your parents; kill not your children because of poverty – We provide
sustenance for you and for them; come not near to Al-Fawâhish
(shameful sins, illegal sexual intercourse, etc.) whether committed
openly or secretly, and kill not anyone whom Allâh has forbidden,
except for a just cause (according to Islâmic law). This He has
commanded you that you may understand. 152. And come not near to the
orphan’s property, except to improve it, until he (or she) attains the
age of full strength; and give full measure and full weight with
justice. We burden not any person, but that which he can bear.And
whenever you give your word (i.e. judge between men or give evidence,
etc.), say the truth even if a near relative is concerned, and fulfill
the Covenant of Allâh, This He commands you, that you may remember.
17: 32. And come not near to the unlawful sexual intercourse. Verily,
it is a Fâhishah [i.e. anything that transgresses its limits (a great
sin)], and an evil way (that leads one to Hell unless Allâh forgives
him). The evidence from the Prophet’s tradition is: Narrated ‘Ubada
bin As-Samit: I, along with a group of people, gave the pledge of
allegiance to Allah’s Apostle. He said, "I take your Pledge on the
condition that you (1) will not join partners in worship with Allah,
(2) will not steal, (3) will not commit illegal sexual intercourse,
(4) will not kill your offspring, (5) will not slander, (6) and will
not disobey me when I order you to do good. Whoever among you will
abide by his pledge, his reward will be with Allah, and whoever
commits any of those sins and receives the punishment in this world,
that punishment will be an expiation for his sins and purification;
but if Allah screens him, then it will be up to Allah to punish him if
He will or excuse Him, if He will."

7- Islam requires belief in all the prophets of God and the former
original revealed Books.4: 136. O you who believe! Believe in Allâh,
and His Messenger (Muhammad), and the Book (the Qur’ân) which He has
sent down to His Messenger, and the Scripture which He sent down to
those before (him), and whosoever disbelieves in Allâh, His Angels,
His Books, His Messengers, and the Last Day, then indeed he has
strayed far away.

8- The Prophet of Islam (peace and blessings of Allah be upon him),
is the only prophet whose followers took great authenticity care of
even the smallest details of his biography, and recorded them in well-
known sources which are considered to be the second source of Islamic
legislation.

9- While the missions of the previous prophets of God were addressed
to specific nations at specific times, Islam is directed to all human
beings until the Last Hour. 34: 28. And We have not sent you (O
Muhammad) except as a giver of glad tidings and a warner to all
mankind, but most of men know not. 10- Islam acquits the prophets of
the horrible misdeeds, which the Bible accuses them of committing.38:
47. And they are with Us, verily, of the chosen and the best!

11- Islam ordains five prayers throughout the day and night, so the
Muslim is in touch with his Creator at all times.11:114. And perform
As-Salât (Iqâmat-as-Salât), at the two ends of the day and in some
hours of the night [i.e. the five compulsory Salât (prayers)]. Verily,
the good deeds remove the evil deeds (i.e. small sins). That is a
reminder (an advice) for the mindful (those who accept advice).

12- Ways of gaining rewards are innumerable in Islam. A Muslim is
rewarded for whatever he does to draw himself closer to Allah. 99:7.
So whosoever does good equal to the weight of an atom (or a small
ant), shall see it. The Prophet (peace and blessings of Allah be upon
him) said, "Charity is obligatory everyday on every joint of a human
being. If one helps a person in matters concerning his riding animal
by helping him to ride it or by lifting his luggage on to it, all this
will be regarded charity. A good word, and every step one takes to
offer the compulsory Congregational prayer, is regarded as charity;
and guiding somebody on the road is regarded as charity."

13- Islam encourages people to repent by leaving the door open to
them to return to the Creator at any time, who assuredly will forgive
all their previous sins.39: 53.Say: "O ‘Ibâdî (My slaves) who have
transgressed against themselves (by committing evil deeds and sins)!
Despair not of the Mercy of Allâh, verily Allâh forgives all sins..
Truly, He is Oft-Forgiving, Most Merciful.25: 70. Except those who
repent and believe (in Islâmic Monotheism), and do righteous deeds,
for those, Allâh will change their sins into good deeds, and Allâh is
Oft-Forgiving, Most Merciful.

14- Islam imposes Jihad on Muslims when oppressed, so that there will
be no worshipping of any associates with Allah.8:39. And fight them
until there is no more Fitnah (disbelief and polytheism: i.e.
worshipping others besides Allâh) and the religion (worship) will all
be for Allâh Alone [in the whole of the world ]. But if they cease
(worshipping others besides Allâh), then certainly, Allâh is All-Seer
of what they do.22: 40. Those who have been expelled from their homes
unjustly only because they said: "Our Lord is Allâh." For had it not
been that Allâh checks one set of people by means of another,
monasteries, churches, synagogues, and mosques, wherein the Name of
Allâh is mentioned much would surely have been pulled down. Verily,
Allâh will help those who help His (Cause). Truly, Allâh is All-
Strong, All-Mighty. This demonstrates the wisdom of jihad; it is meant
to establish the religion of Allah; monotheism/Islam, or preventing
the infidels from harming the believers, and paving the way to worship
Allah and apply His laws.

15- Islam prohibits adding or omitting anything to or from the Islamic
teachings to preserve and maintain it as exactly as when is was
revealed to Prophet Muhammad (peace and blessings of Allah be upon
him).The Prophet (peace and blessings of Allah be upon him) said:
“Whoever innovates something in this matter of ours [i.e., Islam] that
is not a part of it will have it rejected

——————————–
For more information about Islam

http://english.islamway.com/

http://www.islamhouse.com/

http://www.discoverislam.com/

http://www.islambasics.com/index.php

http://english.islamway.com/

http://www.islamtoday.net/english/

http://www.islamweb.net/ver2/MainPage/indexe.php

http://www.sultan.org/

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